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Sample records for 3-d velocity fields

  1. Visualizing 3D velocity fields near contour surfaces

    SciTech Connect

    Max, N.; Crawfis, R.; Grant, C.

    1994-03-01

    Vector field rendering is difficult in 3D because the vector icons overlap and hide each other. We propose four different techniques for visualizing vector fields only near surfaces. The first uses motion blurred particles in a thickened region around the surface. The second uses a voxel grid to contain integral curves of the vector field. The third uses many antialiased lines through the surface, and the fourth uses hairs sprouting from the surface and then bending in the direction of the vector field. All the methods use the graphite pipeline, allowing real time rotation and interaction, and the first two methods can animate the texture to move in the flow determined by the velocity field.

  2. Bayesian 3D velocity field reconstruction with VIRBIUS

    NASA Astrophysics Data System (ADS)

    Lavaux, Guilhem

    2016-03-01

    I describe a new Bayesian-based algorithm to infer the full three dimensional velocity field from observed distances and spectroscopic galaxy catalogues. In addition to the velocity field itself, the algorithm reconstructs true distances, some cosmological parameters and specific non-linearities in the velocity field. The algorithm takes care of selection effects, miscalibration issues and can be easily extended to handle direct fitting of e.g. the inverse Tully-Fisher relation. I first describe the algorithm in details alongside its performances. This algorithm is implemented in the VIRBIUS (VelocIty Reconstruction using Bayesian Inference Software) software package. I then test it on different mock distance catalogues with a varying complexity of observational issues. The model proved to give robust measurement of velocities for mock catalogues of 3000 galaxies. I expect the core of the algorithm to scale to tens of thousands galaxies. It holds the promises of giving a better handle on future large and deep distance surveys for which individual errors on distance would impede velocity field inference.

  3. 3-D seismic velocity and attenuation structures in the geothermal field

    SciTech Connect

    Nugraha, Andri Dian; Syahputra, Ahmad; Fatkhan,; Sule, Rachmat

    2013-09-09

    We conducted delay time tomography to determine 3-D seismic velocity structures (Vp, Vs, and Vp/Vs ratio) using micro-seismic events in the geothermal field. The P-and S-wave arrival times of these micro-seismic events have been used as input for the tomographic inversion. Our preliminary seismic velocity results show that the subsurface condition of geothermal field can be fairly delineated the characteristic of reservoir. We then extended our understanding of the subsurface physical properties through determining of attenuation structures (Qp, Qs, and Qs/Qp ratio) using micro-seismic waveform. We combined seismic velocities and attenuation structures to get much better interpretation of the reservoir characteristic. Our preliminary attanuation structures results show reservoir characterization can be more clearly by using the 3-D attenuation model of Qp, Qs, and Qs/Qp ratio combined with 3-D seismic velocity model of Vp, Vs, and Vp/Vs ratio.

  4. Simultaneous measurement of 3D zooplankton trajectories and surrounding fluid velocity field in complex flows.

    PubMed

    Adhikari, Deepak; Gemmell, Brad J; Hallberg, Michael P; Longmire, Ellen K; Buskey, Edward J

    2015-11-01

    We describe an automated, volumetric particle image velocimetry (PIV) and tracking method that measures time-resolved, 3D zooplankton trajectories and surrounding volumetric fluid velocity fields simultaneously and non-intrusively. The method is demonstrated for groups of copepods flowing past a wall-mounted cylinder. We show that copepods execute escape responses when subjected to a strain rate threshold upstream of a cylinder, but the same threshold range elicits no escape responses in the turbulent wake downstream. The method was also used to document the instantaneous slip velocity of zooplankton and the resulting differences in trajectory between zooplankton and non-inertial fluid particles in the unsteady wake flow, showing the method's capability to quantify drift for both passive and motile organisms in turbulent environments. Applications of the method extend to any group of organisms interacting with the surrounding fluid environment, where organism location, larger-scale eddies and smaller-scale fluid deformation rates can all be tracked and analyzed. PMID:26486364

  5. A hybrid experimental-numerical technique for determining 3D velocity fields from planar 2D PIV data

    NASA Astrophysics Data System (ADS)

    Eden, A.; Sigurdson, M.; Mezić, I.; Meinhart, C. D.

    2016-09-01

    Knowledge of 3D, three component velocity fields is central to the understanding and development of effective microfluidic devices for lab-on-chip mixing applications. In this paper we present a hybrid experimental-numerical method for the generation of 3D flow information from 2D particle image velocimetry (PIV) experimental data and finite element simulations of an alternating current electrothermal (ACET) micromixer. A numerical least-squares optimization algorithm is applied to a theory-based 3D multiphysics simulation in conjunction with 2D PIV data to generate an improved estimation of the steady state velocity field. This 3D velocity field can be used to assess mixing phenomena more accurately than would be possible through simulation alone. Our technique can also be used to estimate uncertain quantities in experimental situations by fitting the gathered field data to a simulated physical model. The optimization algorithm reduced the root-mean-squared difference between the experimental and simulated velocity fields in the target region by more than a factor of 4, resulting in an average error less than 12% of the average velocity magnitude.

  6. Retrieving 3D Velocity Fields of Glaciers from X-band SAR Data and Comparison with GPS Observations

    NASA Astrophysics Data System (ADS)

    Magnússon, E.; Nagler, T.; Hetzenecker, M.; Palsson, F.; Scharrer, K.; Floricioiu, D.; Berthier, E.; Gudmundsson, S.; Rott, H.

    2013-12-01

    We present 3D velocity fields obtained from time series of TerraSAR-X and TanDEM-X images acquired over the ablation area of the Breidamerkurjökull outlet glacier of Vatnjökull Ice Cap (Iceland) in 2008-2012. Coherent and incoherent offset tracking is applied to repeat pass X-Band data to obtain ice displacement in cross and along track direction. Three methods are tested and compared to extract fields of the 3D ice velocity. First, the conventional surface parallel approach, which we consider as an approximation for deriving the horizontal motion rate, but does not reveal a realistic vertical motion. Second, the combination of offset tracking results from almost simultaneous observations from ascending and descending orbits measuring the glacier motion in four different directions, allowing calculation of the 3D velocity fields without any additional approximations. Third, deriving full 3D velocity fields by using the horizontal flow direction, derived from the ascending-descending combination, as constrain on offset tracking results from a single pair of SAR images. The latter two methods reveal a measurement of the vertical ice motion plus ablation, hence equivalent to the vertical motion component measured by GPS station fixed on a platform laying on the ice surface. The results from all methods are compared with such GPS measurements recorded by permanent stations on the glacier in 2008-2012 and the errors of the different methods are calculated. Additionally, we approximate the contribution of these 3D flow fields to elevation changes (emergence/submergence velocity plus net balance) and compare it with elevation changes from surface DEMs obtained in 2008 (SPIRIT), 2010 (airborne LIDAR) and 2012 (TanDEM-X).

  7. On the Velocity Field and the 3D Structure of the Galactic Soccer Ball Abell 43

    NASA Astrophysics Data System (ADS)

    Rauch, Thomas; Werner, Klaus; Ercolano, Barbara; Köppen, Joachim

    2005-11-01

    Planetary nebulae (PNe) and their central stars (CSs) are ideal tools to test evolutionary theory: photospheric properties of their exciting stars give stringent constraints for theoretical predictions of stellar evolution. The nebular abundances display the star's photosphere chemical composition at the time of the nebula's ejection which allows to look back into the history of stellar evolution. More importantly, they even provide a possibility to investigate on the chemical evolution of our Galaxy because most of the nuclear processed material goes back into the interstellar medium via PNe. The recent developments in observation techniques and the new three-dimensional photoionization code MOCASSIN (Ercolano et al. 2003) enable us to analyze PNe properties accurately by the construction of consistent models of PNe and CSs. In addition to PNe imaging and spectroscopy, detailed information about the velocity field within the PNe is a pre-requisite to employ de-projection techniques in modeling the physical structure of the PNe.

  8. Present-Day 3D Velocity Field of Eastern North America Based on Continuous GPS Observations

    NASA Astrophysics Data System (ADS)

    Goudarzi, Mohammad Ali; Cocard, Marc; Santerre, Rock

    2016-07-01

    The Saint Lawrence River valley in eastern Canada was studied using observations of continuously operating GPS (CGPS) stations. The area is one of the most seismically active regions in eastern North America characterized by many earthquakes, which is also subject to an ongoing glacial isostatic adjustment. We present the current three-dimensional velocity field of eastern North America obtained from more than 14 years (9 years on average) of data at 112 CGPS stations. Bernese GNSS and GITSA software were used for CGPS data processing and position time series analysis, respectively. The results show the counterclockwise rotation of the North American plate in the No-Net-Rotation model with the average of 16.8 ± 0.7 mm/year constrained to ITRF 2008. We also present an ongoing uplift model for the study region based on the present-day CGPS observations. The model shows uplift all over eastern Canada with the maximum rate of 13.7 ± 1.2 mm/year and subsidence to the south mainly over northern USA with a typical rate of -1 to -2 mm/year and the minimum value of -2.7 ± 1.4 mm/year. We compared our model with the rate of radial displacements from the ICE-5G model. Both models agree within 0.02 mm/year at the best stations; however, our model shows a systematic spatial tilt compared to ICE-5G. The misfits between two models amount to the maximum relative subsidence of -6.1 ± 1.1 mm/year to the east and maximum relative uplift of 5.9 ± 2.7 mm/year to the west. The intraplate horizontal velocities are radially outward from the centers of maximum uplift and are inward to the centers of maximum subsidence with the typical velocity of 1-1.6 ± 0.4 mm/year that is in agreement with the ICE-5G model to the first order.

  9. Present-Day 3D Velocity Field of Eastern North America Based on Continuous GPS Observations

    NASA Astrophysics Data System (ADS)

    Goudarzi, Mohammad Ali; Cocard, Marc; Santerre, Rock

    2016-03-01

    The Saint Lawrence River valley in eastern Canada was studied using observations of continuously operating GPS (CGPS) stations. The area is one of the most seismically active regions in eastern North America characterized by many earthquakes, which is also subject to an ongoing glacial isostatic adjustment. We present the current three-dimensional velocity field of eastern North America obtained from more than 14 years (9 years on average) of data at 112 CGPS stations. Bernese GNSS and GITSA software were used for CGPS data processing and position time series analysis, respectively. The results show the counterclockwise rotation of the North American plate in the No-Net-Rotation model with the average of 16.8 ± 0.7 mm/year constrained to ITRF 2008. We also present an ongoing uplift model for the study region based on the present-day CGPS observations. The model shows uplift all over eastern Canada with the maximum rate of 13.7 ± 1.2 mm/year and subsidence to the south mainly over northern USA with a typical rate of -1 to -2 mm/year and the minimum value of -2.7 ± 1.4 mm/year. We compared our model with the rate of radial displacements from the ICE-5G model. Both models agree within 0.02 mm/year at the best stations; however, our model shows a systematic spatial tilt compared to ICE-5G. The misfits between two models amount to the maximum relative subsidence of -6.1 ± 1.1 mm/year to the east and maximum relative uplift of 5.9 ± 2.7 mm/year to the west. The intraplate horizontal velocities are radially outward from the centers of maximum uplift and are inward to the centers of maximum subsidence with the typical velocity of 1-1.6 ± 0.4 mm/year that is in agreement with the ICE-5G model to the first order.

  10. 3D tomographic reconstruction of the internal velocity field of an immiscible drop in a shear flow

    NASA Astrophysics Data System (ADS)

    Kerdraon, Paul; Dalziel, Stuart B.; Goldstein, Raymond E.; Landel, Julien R.; Peaudecerf, Francois J.

    2015-11-01

    We study experimentally the internal flow of a drop attached to a flat substrate and immersed in an immiscible shear flow. Transport inside the drop can play a crucial role in cleaning applications. Internal advection can enhance the mass transfer across the drop surface, thus increasing the cleaning rate. We used microlitre water-glycerol drops on a hydrophobic substrate. The drops were spherical and did not deform significantly under the shear flow. An oil phase of relative viscosity 0.01 to 1 was flowed over the drop. Typical Reynolds numbers inside the drops were of the order of 0.1 to 10. Using confocal microscopy, we performed 3D tomographic reconstruction of the flow field in the drop. The in-plane velocity field was measured using micro-PIV, and the third velocity component was computed from incompressibility. To our knowledge, this study gives the first experimental measurement of the three-dimensional internal velocity field of a drop in a shear flow. Numerical simulations and theoretical models published in the past 30 years predict a toroidal internal recirculation flow, for which the entire surface flows streamwise. However, our measurements reveal a qualitatively different picture with a two-lobed recirculation, featuring two stagnation points at the surface and a reverse surface flow closer to the substrate. This finding appears to be independent of Reynolds number and viscosity ratio in the ranges studied; we conjecture that the observed flow is due to the effect of surfactants at the drop surface.

  11. The 3-D strain patterns in Turkey using geodetic velocity fields from the RTK-CORS (TR) network

    NASA Astrophysics Data System (ADS)

    Kutoglu, Hakan Senol; Toker, Mustafa; Mekik, Cetin

    2016-03-01

    This study presents our use of GPS data to obtain and quantify the full continuous strain tensor using a 3-D velocity field in Turkey. In this study, GPS velocities improve the estimation of short-term strain tensor fields for determining the seismic hazard of Turkey. The tensorial analysis presents different aspects of deformation, such as the normal and shear strains, including their directions, the compressional and extensional strains. This analysis is appropriate for the characterizing the state of the current seismic deformation. GPS velocity data from continuous measurements (2009-2012) to estimate deformations were processed using the GAMIT/GLOBK software. Using high-rate GPS data from permanent 146 GNSS stations (RTK-CORS-TR network), the strain distribution was determined and interpolated using a biharmonic spline technique. We show the strain field patterns within axial and plane form at several critical locations, and discuss these results within the context of the seismic and tectonic deformation of Turkey. We conclude that the knowledge of the crustal strain patterns provides important information on the location of the main faults and strain accumulation for the hazard assessment. The results show an agreement between the seismic and tectonic strains confirming that there are active crustal deformations in Turkey.

  12. 3D field harmonics

    SciTech Connect

    Caspi, S.; Helm, M.; Laslett, L.J.

    1991-03-30

    We have developed an harmonic representation for the three dimensional field components within the windings of accelerator magnets. The form by which the field is presented is suitable for interfacing with other codes that make use of the 3D field components (particle tracking and stability). The field components can be calculated with high precision and reduced cup time at any location (r,{theta},z) inside the magnet bore. The same conductor geometry which is used to simulate line currents is also used in CAD with modifications more readily available. It is our hope that the format used here for magnetic fields can be used not only as a means of delivering fields but also as a way by which beam dynamics can suggest correction to the conductor geometry. 5 refs., 70 figs.

  13. Azimuthally Anisotropic 3D Velocity Continuation

    DOE PAGESBeta

    Burnett, William; Fomel, Sergey

    2011-01-01

    We extend time-domain velocity continuation to the zero-offset 3D azimuthally anisotropic case. Velocity continuation describes how a seismic image changes given a change in migration velocity. This description turns out to be of a wave propagation process, in which images change along a velocity axis. In the anisotropic case, the velocity model is multiparameter. Therefore, anisotropic image propagation is multidimensional. We use a three-parameter slowness model, which is related to azimuthal variations in velocity, as well as their principal directions. This information is useful for fracture and reservoir characterization from seismic data. We provide synthetic diffraction imaging examples to illustratemore » the concept and potential applications of azimuthal velocity continuation and to analyze the impulse response of the 3D velocity continuation operator.« less

  14. Simultaneous measurement of the geometry and the internal 3D velocity field of a micron sized droplet confined in a channel using Astigmatism-PTV

    NASA Astrophysics Data System (ADS)

    Mack, Tobias; Cierpka, Christian; Kähler, Christian J.

    2012-11-01

    Astigmatism-PTV is a method that allows to measure with a single camera the fully three-dimensional, three-component velocity field. The technique is ideally suited for microfluidic velocity measurements without errors due to in-plane and out-of-plane averaging (Cierpka et al. Meas Scie Tech 21, 2010). Recently it was shown, that the interface between two fluids or the surrounding fluid and droplets or bubbles can be estimated as well with the technique (Rossi et al., Meas Scie Tech 22, 2010). In this contribution the advantages of both techniques are combined to measure the shape of a droplet inside a micro channel along with the internal 3D flow field of the droplet induced by the surrounding fluid. For the current investigation, particles were only distributed within oil-droplets. Therefore the shape of the droplet could be later reconstructed by the volumetric particle positions and the velocity can be estimated tracking the same particles in consecutive frames of the same dataset. The procedure allows the simultaneous determination of the shape and the droplet velocity as well as the inner flow field and offers a great potential for current research.

  15. Split view Time-resolved PIV with a CW laser for 3-D measurements of planar velocity field

    NASA Astrophysics Data System (ADS)

    Elzawawy, Amir; Andreopoulos, Yiannis

    2011-11-01

    The demand to increase the temporal resolution of Stereo-PIV systems used in the measurement of highly unsteady flow fields is limited by the low repetition rate of the pulsed lasers and cameras. The availability of high-frame-rate digital cameras and CW lasers opens new possibilities in the development of continuous PIV systems with increased temporal resolution. The present setup consists of a single high-frame-rate camera which can accommodate two simultaneous stereo view images of the deforming fluid on its CMOS sensor obtained by using four different planar mirrors, appropriately positioned This approach offers several advantages over traditional systems with two different cameras. First, it provides identical system parameters for the two views which minimize their differences and thus facilitating robust stereo matching. Second, it eliminates any need of synchronization between both cameras and the laser. And third its cost is substantially lower than the cost of a system with two cameras. The development of the technique will be described and the results of qualification tests in several wind tunnel flows will be presented and discussed. Sponsored by NSF Grant #1033117.

  16. A free software for pore-scale modelling: solving Stokes equation for velocity fields and permeability values in 3D pore geometries

    NASA Astrophysics Data System (ADS)

    Gerke, Kirill; Vasilyev, Roman; Khirevich, Siarhei; Karsanina, Marina; Collins, Daniel; Korost, Dmitry; Mallants, Dirk

    2015-04-01

    In this contribution we introduce a novel free software which solves the Stokes equation to obtain velocity fields for low Reynolds-number flows within externally generated 3D pore geometries. Provided with velocity fields, one can calculate permeability for known pressure gradient boundary conditions via Darcy's equation. Finite-difference schemes of 2nd and 4th order of accuracy are used together with an artificial compressibility method to iteratively converge to a steady-state solution of Stokes' equation. This numerical approach is much faster and less computationally demanding than the majority of open-source or commercial softwares employing other algorithms (finite elements/volumes, lattice Boltzmann, etc.) The software consists of two parts: 1) a pre and post-processing graphical interface, and 2) a solver. The latter is efficiently parallelized to use any number of available cores (the speedup on 16 threads was up to 10-12 depending on hardware). Due to parallelization and memory optimization our software can be used to obtain solutions for 300x300x300 voxels geometries on modern desktop PCs. The software was successfully verified by testing it against lattice Boltzmann simulations and analytical solutions. To illustrate the software's applicability for numerous problems in Earth Sciences, a number of case studies have been developed: 1) identifying the representative elementary volume for permeability determination within a sandstone sample, 2) derivation of permeability/hydraulic conductivity values for rock and soil samples and comparing those with experimentally obtained values, 3) revealing the influence of the amount of fine-textured material such as clay on filtration properties of sandy soil. This work was partially supported by RSF grant 14-17-00658 (pore-scale modelling) and RFBR grants 13-04-00409-a and 13-05-01176-a.

  17. Constructing 3D isotropic and azimuthally anisotropic crustal models across USArray using Rayleigh wave phase velocity and ellipticity: inferring continental stress field

    NASA Astrophysics Data System (ADS)

    Lin, F. C.; Schmandt, B.; Tsai, V. C.

    2014-12-01

    The EarthScope USArray Transportable Array (TA) has provided a great opportunity for imaging the detailed lithospheric structure beneath the continental US. In this presentation, we will report our recent progress on constructing detailed 3D isotropic and anisotropic crustal models of the contiguous US using Rayleigh wave phase velocity and ellipticity measurements across TA. In particular, we will discuss our recent methodology development of extracting short period Rayleigh wave ellipticity, or Rayleigh-wave H/V (horizontal to vertical) amplitude ratios, using multicomponent noise cross-correlations. To retain the amplitude ratio information between vertical and horizontal components, for each station, we perform daily noise pre-processing (temporal normalization and spectrum whitening) simultaneously for all three components. For each station pair, amplitude measurements between cross-correlations of different components (radial-radial, radial-vertical, vertical-radial and vertical-vertical) are then used to determine the Rayleigh-wave H/V ratios at the two station locations. Measurements from all available station pairs are used to determine isotropic and directionally dependent Rayleigh-wave H/V ratios at each location between 8- and 24-second period. The isotropic H/V ratio maps, combined with previous longer period Rayleigh-wave H/V ratio maps from earthquakes and Rayleigh-wave phase velocity maps from both ambient noise and earthquakes, are used to invert for a new 3-D isotropic crustal and upper-mantle model in the western United States. The new model has an outstanding vertical resolution in the upper crust and tradeoffs between different parameters are mitigated. A clear 180-degree periodicity is observed in the directionally dependent H/V ratio measurements for many locations where upper crustal anisotropy is likely strong. Across the US, good correlation is observed between the inferred fast directions in the upper crust and documented maximum

  18. Shear wave velocity for the upper 30 m: Combining a 3D voxel model and seismic CPTS for the Groningen gas field, the Netherlands.

    NASA Astrophysics Data System (ADS)

    Dambrink, Roula; Gunnink, Jan; Stafleu, Jan; de Lange, Ger; Kruiver, Pauline

    2016-04-01

    The Groningen gas field in the Netherlands is one of the largest gas fields of Europe and has been in production since the 1960's. Due to the progressive depletion of the reservoir, induced seismic activity has increased in recent years. In 2012, an earthquake of magnitude 3.6 initiated further research in prediction and management of risks related to man-induced earthquakes. Last year the government decided to reduce the gas extraction for this reason. One of the topics of concern is the large difference in earthquake-related damage to buildings which, in addition to the distance to the epicenter, appears to be also related to the composition of the shallow subsurface. To improve the spatial distribution of Shear Wave Velocities (Vs) in the shallow subsurface, used for hazard prediction, the Geological Survey of the Netherlands and Deltares constructed a Vs30 map of the upper 30 m of the gas field. In this map a high-resolution geological model (GeoTOP) is combined with seismic cone penetration tests (SCPT) from the area. The GeoTOP model is a 3D voxel model of the upper 50 m, in which each voxel (100x100x0.5 m) is attributed with lithostratigraphy and the most likely lithological class (peat, clay, fine sand, etc.). To obtain statistical distributions (with mean and standard deviation) of Vs for each combination of lithostratigraphical unit and lithoclass, 60 SCPTs were analyzed. In this way, it was possible to assign a specific Vs to each voxel in the model. For each voxel in the stack of voxels that covers the upper 30 m (i.e. 60 voxels), a Vs value was randomly drawn from the statistical distribution of the lithostratigraphical - lithoclass combination it belongs to. The Vs30 for each voxelstack is then calculated using the harmonic mean of the Vs of the 60 voxels. By repeating this procedure 100 times, an (average) Vs30 map and the uncertainty in Vs30 has been constructed. Using the procedure described above we were able to delineate zones with distinct Vs30

  19. Palacios field: A 3-D case history

    SciTech Connect

    McWhorter, R.; Torguson, B.

    1994-12-31

    In late 1992, Mitchell Energy Corporation acquired a 7.75 sq mi (20.0 km{sup 2}) 3-D seismic survey over Palacios field. Matagorda County, Texas. The company shot the survey to help evaluate the field for further development by delineating the fault pattern of the producing Middle Oligocene Frio interval. They compare the mapping of the field before and after the 3-D survey. This comparison shows that the 3-D volume yields superior fault imaging and interpretability compared to the dense 2-D data set. The problems with the 2-D data set are improper imaging of small and oblique faults and insufficient coverage over a complex fault pattern. Whereas the 2-D data set validated a simple fault model, the 3-D volume revealed a more complex history of faulting that includes three different fault systems. This discovery enabled them to reconstruct the depositional and structural history of Palacios field.

  20. Measurements of 3D slip velocities and plasma column lengths of a gliding arc discharge

    SciTech Connect

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas; Aldén, Marcus; Li, Zhongshan E-mail: alpers@ma.tum.de; Moseev, Dmitry; Kusano, Yukihiro; Salewski, Mirko; Alpers, Andreas E-mail: alpers@ma.tum.de; Gritzmann, Peter; Schwenk, Martin

    2015-01-26

    A non-thermal gliding arc discharge was generated at atmospheric pressure in an air flow. The dynamics of the plasma column and tracer particles were recorded using two synchronized high-speed cameras. Whereas the data analysis for such systems has previously been performed in 2D (analyzing the single camera image), we provide here a 3D data analysis that includes 3D reconstructions of the plasma column and 3D particle tracking velocimetry based on discrete tomography methods. The 3D analysis, in particular, the determination of the 3D slip velocity between the plasma column and the gas flow, gives more realistic insight into the convection cooling process. Additionally, with the determination of the 3D slip velocity and the 3D length of the plasma column, we give more accurate estimates for the drag force, the electric field strength, the power per unit length, and the radius of the conducting zone of the plasma column.

  1. 3D finite element simulations of high velocity projectile impact

    NASA Astrophysics Data System (ADS)

    Ožbolt, Joško; İrhan, Barış; Ruta, Daniela

    2015-09-01

    An explicit three-dimensional (3D) finite element (FE) code is developed for the simulation of high velocity impact and fragmentation events. The rate sensitive microplane material model, which accounts for large deformations and rate effects, is used as a constitutive law. In the code large deformation frictional contact is treated by forward incremental Lagrange multiplier method. To handle highly distorted and damaged elements the approach based on the element deletion is employed. The code is then used in 3D FE simulations of high velocity projectile impact. The results of the numerical simulations are evaluated and compared with experimental results. It is shown that it realistically predicts failure mode and exit velocities for different geometries of plain concrete slab. Moreover, the importance of some relevant parameters, such as contact friction, rate sensitivity, bulk viscosity and deletion criteria are addressed.

  2. Structured light field 3D imaging.

    PubMed

    Cai, Zewei; Liu, Xiaoli; Peng, Xiang; Yin, Yongkai; Li, Ameng; Wu, Jiachen; Gao, Bruce Z

    2016-09-01

    In this paper, we propose a method by means of light field imaging under structured illumination to deal with high dynamic range 3D imaging. Fringe patterns are projected onto a scene and modulated by the scene depth then a structured light field is detected using light field recording devices. The structured light field contains information about ray direction and phase-encoded depth, via which the scene depth can be estimated from different directions. The multidirectional depth estimation can achieve high dynamic 3D imaging effectively. We analyzed and derived the phase-depth mapping in the structured light field and then proposed a flexible ray-based calibration approach to determine the independent mapping coefficients for each ray. Experimental results demonstrated the validity of the proposed method to perform high-quality 3D imaging for highly and lowly reflective surfaces. PMID:27607639

  3. Current plate boundary deformation of the Afar rift from a 3-D velocity field inversion of InSAR and GPS

    NASA Astrophysics Data System (ADS)

    Pagli, Carolina; Wang, Hua; Wright, Tim J.; Calais, Eric; Lewi, Elias

    2014-11-01

    Extension, faulting, and magmatism are the main controls on the magnitude and localization of strain at mid-ocean ridges. However, the temporal and spatial patterns of such processes are not clear since the strain distribution has not been resolved in the past at sufficient spatial resolution and over extended areas. Interferometric synthetic aperture radar (InSAR) and GPS data with unprecedented resolution are now available to us from the Afar rift of Ethiopia. Here we use a velocity field method to combine InSAR and GPS to form the first high-resolution continuous three-dimensional velocity field of Afar. We study an area that is 500 km wide and 700 km long, covering three branches of the Afar continental rift and their triple junctions. Our velocity field shows that plate spreading is currently achieved in Afar in contrasting modes. A transient postdiking deformation is focused at the Dabbahu rift segment, while in central Afar, spreading is distributed over several overlapping segments and southern Afar exhibits an interdiking deformation pattern focused at the Asal-Ghoubbet segment. We find that current spreading rates at Dabbahu, following the 2005-2010 intrusions, are up to 110 mm/yr, 6 times larger than the long-term plate divergence. A segment-centered uplift of up to 80 mm/yr also occurs, indicating that magma flow is still a primary mechanism of deformation during postdiking. On the other hand, no vertical displacements are currently observed in central and southern Afar, suggesting lack of significant magmatic activity at shallow levels.

  4. Measuring the Stellar Halo Velocity Anisotropy With 3D Kinematics

    NASA Astrophysics Data System (ADS)

    Cunningham, Emily C.; Deason, Alis J.; Guhathakurta, Puragra; Rockosi, Constance M.; van der Marel, Roeland P.; Sohn, S. Tony

    2016-08-01

    We present the first measurement of the anisotropy parameter β using 3D kinematic information outside of the solar neighborhood. Our sample consists of 13 Milky Way halo stars with measured proper motions and radial velocities in the line of sight of M31. Proper motions were measured using deep, multi-epoch HST imaging, and radial velocities were measured from Keck II/DEIMOS spectra. We measure β = -0.3-0.9 +0.4, which is consistent with isotropy, and inconsistent with measurements in the solar neighborhood. We suggest that this may be the kinematic signature of a relatively early, massive accretion event, or perhaps several such events.

  5. 3-D Flow Visualization with a Light-field Camera

    NASA Astrophysics Data System (ADS)

    Thurow, B.

    2012-12-01

    Light-field cameras have received attention recently due to their ability to acquire photographs that can be computationally refocused after they have been acquired. In this work, we describe the development of a light-field camera system for 3D visualization of turbulent flows. The camera developed in our lab, also known as a plenoptic camera, uses an array of microlenses mounted next to an image sensor to resolve both the position and angle of light rays incident upon the camera. For flow visualization, the flow field is seeded with small particles that follow the fluid's motion and are imaged using the camera and a pulsed light source. The tomographic MART algorithm is then applied to the light-field data in order to reconstruct a 3D volume of the instantaneous particle field. 3D, 3C velocity vectors are then determined from a pair of 3D particle fields using conventional cross-correlation algorithms. As an illustration of the concept, 3D/3C velocity measurements of a turbulent boundary layer produced on the wall of a conventional wind tunnel are presented. Future experiments are planned to use the camera to study the influence of wall permeability on the 3-D structure of the turbulent boundary layer.Schematic illustrating the concept of a plenoptic camera where each pixel represents both the position and angle of light rays entering the camera. This information can be used to computationally refocus an image after it has been acquired. Instantaneous 3D velocity field of a turbulent boundary layer determined using light-field data captured by a plenoptic camera.

  6. Pore-scale intermittent velocity structure underpinning anomalous transport through 3-D porous media

    NASA Astrophysics Data System (ADS)

    Kang, Peter K.; Anna, Pietro; Nunes, Joao P.; Bijeljic, Branko; Blunt, Martin J.; Juanes, Ruben

    2014-09-01

    We study the nature of non-Fickian particle transport in 3-D porous media by simulating fluid flow in the intricate pore space of real rock. We solve the full Navier-Stokes equations at the same resolution as the 3-D micro-CT (computed tomography) image of the rock sample and simulate particle transport along the streamlines of the velocity field. We find that transport at the pore scale is markedly anomalous: longitudinal spreading is superdiffusive, while transverse spreading is subdiffusive. We demonstrate that this anomalous behavior originates from the intermittent structure of the velocity field at the pore scale, which in turn emanates from the interplay between velocity heterogeneity and velocity correlation. Finally, we propose a continuous time random walk model that honors this intermittent structure at the pore scale and captures the anomalous 3-D transport behavior at the macroscale.

  7. The USGS 3D Seismic Velocity Model for Northern California

    NASA Astrophysics Data System (ADS)

    Brocher, T. M.; Aagaard, B.; Simpson, R. W.; Jachens, R. C.

    2006-12-01

    We present a new regional 3D seismic velocity model for Northern California for use in strong motion simulations of the 1906 San Francisco and other earthquakes. The model includes compressional-wave velocity (Vp), shear-wave velocity (Vs), density, and intrinsic attenuation (Qp, Qs). These properties were assigned for each rock type in a 3D geologic model derived from surface outcrops, boreholes, gravity and magnetic data, and seismic reflection, refraction, and tomography studies. A detailed description of the model, USGS Bay Area Velocity Model 05.1.0, is available online [http://www.sf06simulation.org/geology/velocitymodel]. For ground motion simulations Vs and Qs are more important parameters than Vp and Qp because the strongest ground motions are generated chiefly by shear and surface wave arrivals. Because Vp data are more common than Vs data, however, we first developed Vp versus depth relations for each rock type and then converted these to Vs versus depth relations. For the most important rock types in Northern California we compiled measurements of Vp versus depth using borehole logs, laboratory measurements on hand samples, seismic refraction profiles, and tomography models. These rock types include Salinian and Sierran granitic rocks, metagraywackes and greenstones of the Franciscan Complex, Tertiary and Mesozoic sedimentary and volcanic rocks, and Quaternary and Holocene deposits (Brocher, USGS OFR 05-1317, 2005). Vp versus depth curves were converted to Vs versus depth curves using new empirical nonlinear relations between Vs and Vp (Brocher, BSSA, 2005). These relations, showing that Poisson's ratio is a nonlinear function of Vp, were similarly based on compilations of diverse Vs and Vp measurements on a large suite of rock types, mainly from California and the Pacific Northwest. The model is distributed in a discretized form with routines to query the model using C++, C, and Fortran 77 programming languages. The geologic model was discretized at

  8. Visualization of 3-D tensor fields

    NASA Technical Reports Server (NTRS)

    Hesselink, L.

    1996-01-01

    Second-order tensor fields have applications in many different areas of physics, such as general relativity and fluid mechanics. The wealth of multivariate information in tensor fields makes them more complex and abstract than scalar and vector fields. Visualization is a good technique for scientists to gain new insights from them. Visualizing a 3-D continuous tensor field is equivalent to simultaneously visualizing its three eigenvector fields. In the past, research has been conducted in the area of two-dimensional tensor fields. It was shown that degenerate points, defined as points where eigenvalues are equal to each other, are the basic singularities underlying the topology of tensor fields. Moreover, it was shown that eigenvectors never cross each other except at degenerate points. Since we live in a three-dimensional world, it is important for us to understand the underlying physics of this world. In this report, we describe a new method for locating degenerate points along with the conditions for classifying them in three-dimensional space. Finally, we discuss some topological features of three-dimensional tensor fields, and interpret topological patterns in terms of physical properties.

  9. Uncertainty assessment of 3D instantaneous velocity model from stack velocities

    NASA Astrophysics Data System (ADS)

    Emanuele Maesano, Francesco; D'Ambrogi, Chiara

    2015-04-01

    3D modelling is a powerful tool that is experiencing increasing applications in data analysis and dissemination. At the same time the need of quantitative uncertainty evaluation is strongly requested in many aspects of the geological sciences and by the stakeholders. In many cases the starting point for 3D model building is the interpretation of seismic profiles that provide indirect information about the geology of the subsurface in the domain of time. The most problematic step in the 3D modelling construction is the conversion of the horizons and faults interpreted in time domain to the depth domain. In this step the dominant variable that could lead to significantly different results is the velocity. The knowledge of the subsurface velocities is related mainly to punctual data (sonic logs) that are often sparsely distributed in the areas covered by the seismic interpretation. The extrapolation of velocity information to wide extended horizons is thus a critical step to obtain a 3D model in depth that can be used for predictive purpose. In the EU-funded GeoMol Project, the availability of a dense network of seismic lines (confidentially provided by ENI S.p.A.) in the Central Po Plain, is paired with the presence of 136 well logs, but few of them have sonic logs and in some portion of the area the wells are very widely spaced. The depth conversion of the 3D model in time domain has been performed testing different strategies for the use and the interpolation of velocity data. The final model has been obtained using a 4 layer cake 3D instantaneous velocity model that considers both the initial velocity (v0) in every reference horizon and the gradient of velocity variation with depth (k). Using this method it is possible to consider the geological constraint given by the geometries of the horizons and the geo-statistical approach to the interpolation of velocities and gradient. Here we present an experiment based on the use of set of pseudo-wells obtained from the

  10. Integrating Mach-Zehnder interferometry with TPIV to measure the time-resolved deformation of a compliant wall along with the 3D velocity field in a turbulent channel flow

    NASA Astrophysics Data System (ADS)

    Zhang, Cao; Miorini, Rinaldo; Katz, Joseph

    2015-11-01

    A system combining tomographic PIV (TPIV) and Mach-Zehnder interferometry (MZI) simultaneously measures the time- resolved 3D flow field and 2D distribution of wall-normal deformation in a turbulent channel flow over a transparent compliant surface. This paper focuses on the experimental techniques and data analysis procedures, but includes sample results. Standard TPIV analysis resolves the log layer of the mean velocity and the linear decrease in total shear stress with distance from the wall. Single-pixel ensemble correlations reveal the buffer layer and top of the viscous sublayer. Analysis of the MZI data consists of two steps, namely critical spatial filtering of interferograms to remove noise and phase demodulation to calculate the surface shape. A new technique to improve the filtration of noise from interferograms based on spatial correlations of small windows is introduced and optimized. Taking advantage of this enhancement, the phase/deformation distribution is calculated directly from arccosines of the intensity, which avoids edge artifacts affecting spectral calculations. Validations using synthetic noisy interferograms indicate that errors associated with correlation-based enhancement are consistently lower and much less sensitive to fringe shape than spectral band-pass filtering. The experimental wavenumber-frequency spectra show that the deformation consists of patterns that are larger than the field of view, surface waves and small-scale patterns. Some of the latter are advected at the freestream velocity, but mostly at 70 % of the freestream, the mean speed at 10 % of the channel half height. Indeed, spatial correlations of the deformation with velocity components peak at this elevation.

  11. Towards an Anisotropic Whole Mantle 3D Elastic Velocity Model

    NASA Astrophysics Data System (ADS)

    Panning, M. P.; Romanowicz, B.; Gung, Y.

    2001-12-01

    Many studies have documented the existence of anisotropy in the earth's upper mantle, concentrated in the top 200 km. This evidence comes from the study of surface waves as well as shear wave splitting. There is also evidence for shear wave splitting in D", at least in well sampled regions. There are some hints of anisotropy at the base of the transition zone. Tomographic models of the upper mantle have been developed with simplifying assumptions about the nature of the anisotropy, in order to minimize the number of free parameters in the inversions. Some assume transverse isotropy (e.g Ekström and Dziewonski, 1997), others include additional degrees of freedom with some realistic constraints on mineralogy (e.g. Montagner and Tanimoto, 1991). Our goal is to investigate anisotropy in the whole mantle, using the framework of waveform inversion, and the nonlinear asymptotic mode coupling theory (NACT), previously developed and applied to the construction of whole-mantle SH velocity models (Li and Romanowicz, 1996; Mégnin and Romanowicz, 2000). For this we require a 3 component dataset, and we have extended our automatic transverse (T) component wavepicking procedures to the vertical (Z) and longitudinal (L) component - a non-trivial task given the large number of phases present in the coupled P-SV system. A useful initial assumption, for which the theory has been readily adapted, is that of transverse isotropy. As a first step towards this, we have been investigating inversions using T component and Z,L component data separately. In particular, this allows us to explore the sampling that can be achieved with Z,L component data alone in the deepest part of the mantle. Indeed, D" is in general much better sampled in SH than in SV, owing to the availability of SHdiff at large distances, while SVdiff decays more rapidly due to mantle-core coupling. We present the results of our resolution experiments and discuss the differences between the 3D SV model obtained in well

  12. Light field display and 3D image reconstruction

    NASA Astrophysics Data System (ADS)

    Iwane, Toru

    2016-06-01

    Light field optics and its applications become rather popular in these days. With light field optics or light field thesis, real 3D space can be described in 2D plane as 4D data, which we call as light field data. This process can be divided in two procedures. First, real3D scene is optically reduced with imaging lens. Second, this optically reduced 3D image is encoded into light field data. In later procedure we can say that 3D information is encoded onto a plane as 2D data by lens array plate. This transformation is reversible and acquired light field data can be decoded again into 3D image with the arrayed lens plate. "Refocusing" (focusing image on your favorite point after taking a picture), light-field camera's most popular function, is some kind of sectioning process from encoded 3D data (light field data) to 2D image. In this paper at first I show our actual light field camera and our 3D display using acquired and computer-simulated light field data, on which real 3D image is reconstructed. In second I explain our data processing method whose arithmetic operation is performed not in Fourier domain but in real domain. Then our 3D display system is characterized by a few features; reconstructed image is of finer resolutions than density of arrayed lenses and it is not necessary to adjust lens array plate to flat display on which light field data is displayed.

  13. Determining 3D Flow Fields via Multi-camera Light Field Imaging

    PubMed Central

    Truscott, Tadd T.; Belden, Jesse; Nielson, Joseph R.; Daily, David J.; Thomson, Scott L.

    2013-01-01

    In the field of fluid mechanics, the resolution of computational schemes has outpaced experimental methods and widened the gap between predicted and observed phenomena in fluid flows. Thus, a need exists for an accessible method capable of resolving three-dimensional (3D) data sets for a range of problems. We present a novel technique for performing quantitative 3D imaging of many types of flow fields. The 3D technique enables investigation of complicated velocity fields and bubbly flows. Measurements of these types present a variety of challenges to the instrument. For instance, optically dense bubbly multiphase flows cannot be readily imaged by traditional, non-invasive flow measurement techniques due to the bubbles occluding optical access to the interior regions of the volume of interest. By using Light Field Imaging we are able to reparameterize images captured by an array of cameras to reconstruct a 3D volumetric map for every time instance, despite partial occlusions in the volume. The technique makes use of an algorithm known as synthetic aperture (SA) refocusing, whereby a 3D focal stack is generated by combining images from several cameras post-capture 1. Light Field Imaging allows for the capture of angular as well as spatial information about the light rays, and hence enables 3D scene reconstruction. Quantitative information can then be extracted from the 3D reconstructions using a variety of processing algorithms. In particular, we have developed measurement methods based on Light Field Imaging for performing 3D particle image velocimetry (PIV), extracting bubbles in a 3D field and tracking the boundary of a flickering flame. We present the fundamentals of the Light Field Imaging methodology in the context of our setup for performing 3DPIV of the airflow passing over a set of synthetic vocal folds, and show representative results from application of the technique to a bubble-entraining plunging jet. PMID:23486112

  14. 3D touchable holographic light-field display.

    PubMed

    Yamaguchi, Masahiro; Higashida, Ryo

    2016-01-20

    We propose a new type of 3D user interface: interaction with a light field reproduced by a 3D display. The 3D display used in this work reproduces a 3D light field, and a real image can be reproduced in midair between the display and the user. When using a finger to touch the real image, the light field from the display will scatter. Then, the 3D touch sensing is realized by detecting the scattered light by a color camera. In the experiment, the light-field display is constructed with a holographic screen and a projector; thus, a preliminary implementation of a 3D touch is demonstrated. PMID:26835952

  15. 3D velocity measurements in a premixed flame by tomographic PIV

    NASA Astrophysics Data System (ADS)

    Tokarev, M. P.; Sharaborin, D. K.; Lobasov, A. S.; Chikishev, L. M.; Dulin, V. M.; Markovich, D. M.

    2015-06-01

    Tomographic particle image velocimetry (PIV) has become a standard tool for 3D velocity measurements in non-reacting flows. However, the majority of the measurements in flows with combustion are limited to small resolved depth compared to the size of the field of view (typically 1 : 10). The limitations are associated with inhomogeneity of the volume illumination and the non-uniform flow seeding, the optical distortions and errors in the 3D calibration, and the unwanted flame luminosity. In the present work, the above constraints were overcome for the tomographic PIV experiment in a laminar axisymmetric premixed flame. The measurements were conducted for a 1 : 1 depth-to-size ratio using a system of eight CCD cameras and a 200 mJ pulsed laser. The results show that camera calibration based on the triangulation of the tracer particles in the non-reacting conditions provided reliable accuracy for the 3D image reconstruction in the flame. The modification of the tomographic reconstruction allowed a posteriori removal of unwanted bright objects, which were located outside of the region of interest but affected the reconstruction quality. This study reports on a novel experience for the instantaneous 3D velocimetry in laboratory-scale flames by using tomographic PIV.

  16. Congruence of 3-D Whole Mantle Models of Shear Velocity

    NASA Astrophysics Data System (ADS)

    Dziewonski, A. M.; Lekic, V.; Romanowicz, B. A.

    2012-12-01

    The range of shear velocity anomalies in published whole mantle models is considerable. This impedes drawing conclusions of importance for geodynamic modeling and for interpretation of mineral physics results. However, if one considers only the models that were built using data that are sensitive to mantle structure at all depths, these models show robust features in their power spectra as a function of depth. On this basis we propose that there are five depth intervals with distinct spectral characteristics. 1. Heterosphere (Moho - 300 km) is characterized by strong power spectrum relatively flat up to degree 6. With lateral shear wavespeed variations as large as 15%, this zone accounts for more than 50% of the entire heterogeneity in the mantle. Differences among models for different tectonic regions decrease rapidly below 300 km depth. 2. Upper mantle buffer zone (300- 500 km) has a flat spectrum and the overall power of heterogeneity drops by an order of magnitude compared to the region above. There may be still weak difference between continents and oceans, but the oceanic regions lose their age dependence. The spectral characteristics do not change across the 410 km discontinuity. 3. Transition zone (500 - 650 km) The degree 2 anomaly becomes dominant. There are long wavelength anomalies in regions of the fastest plate subduction during the last 15-20 Ma, suggesting slab ponding above the 650 km discontinuity. Several slower-than-average anomalies of unknown origin are present in this depth range. 4. Lower mantle buffer zone (650 - 2300 km) has a weak, flat spectrum without long wavelength velocity anomalies that could be interpreted as unfragmented subducted slabs. However, there are three relatively narrow and short high velocity anomalies under Peru, Tonga and Indonesia that may indicate limited slab penetration. 5 Abyssal layer (2300 - CMB) Strong spectrum dominated by degrees 2 and 3. The amplitude is the largest at the CMB and decreases rapidly up to

  17. Direct ambient noise tomography for 3-D near surface shear velocity structure: methodology and applications

    NASA Astrophysics Data System (ADS)

    Yao, H.; Fang, H.; Li, C.; Liu, Y.; Zhang, H.; van der Hilst, R. D.; Huang, Y. C.

    2014-12-01

    Ambient noise tomography has provided essential constraints on crustal and uppermost mantle shear velocity structure in global seismology. Recent studies demonstrate that high frequency (e.g., ~ 1 Hz) surface waves between receivers at short distances can be successfully retrieved from ambient noise cross-correlation and then be used for imaging near surface or shallow crustal shear velocity structures. This approach provides important information for strong ground motion prediction in seismically active area and overburden structure characterization in oil and gas fields. Here we propose a new tomographic method to invert all surface wave dispersion data for 3-D variations of shear wavespeed without the intermediate step of phase or group velocity maps.The method uses frequency-dependent propagation paths and a wavelet-based sparsity-constrained tomographic inversion. A fast marching method is used to compute, at each period, surface wave traveltimes and ray paths between sources and receivers. This avoids the assumption of great-circle propagation that is used in most surface wave tomographic studies, but which is not appropriate in complex media. The wavelet coefficients of the velocity model are estimated with an iteratively reweighted least squares (IRLS) algorithm, and upon iterations the surface wave ray paths and the data sensitivity matrix are updated from the newly obtained velocity model. We apply this new method to determine the 3-D near surface wavespeed variations in the Taipei basin of Taiwan, Hefei urban area and a shale and gas production field in China using the high-frequency interstation Rayleigh wave dispersion data extracted from ambient noisecross-correlation. The results reveal strong effects of off-great-circle propagation of high-frequency surface waves in these regions with above 30% shear wavespeed variations. The proposed approach is more efficient and robust than the traditional two-step surface wave tomography for imaging complex

  18. Simulation of 3D infrared scenes using random fields model

    NASA Astrophysics Data System (ADS)

    Shao, Xiaopeng; Zhang, Jianqi

    2001-09-01

    Analysis and simulation of smart munitions requires imagery for the munition's sensor to view. The traditional infrared background simulations are always limited in the plane scene studies. A new method is described to synthesize the images in 3D view and with various terrains texture. We develop the random fields model and temperature fields to simulate 3D infrared scenes. Generalized long-correlation (GLC) model, one of random field models, will generate both the 3D terrains skeleton data and the terrains texture in this work. To build the terrain mesh with the random fields, digital elevation models (DEM) are introduced in the paper. And texture mapping technology will perform the task of pasting the texture in the concavo-convex surfaces of the 3D scene. The simulation using random fields model is a very available method to produce 3D infrared scene with great randomicity and reality.

  19. Application of Plenoptic PIV for 3D Velocity Measurements Over Roughness Elements in a Refractive Index Matched Facility

    NASA Astrophysics Data System (ADS)

    Thurow, Brian; Johnson, Kyle; Kim, Taehoon; Blois, Gianluca; Best, Jim; Christensen, Ken

    2014-11-01

    The application of Plenoptic PIV in a Refractive Index Matched (RIM) facility housed at Illinois is presented. Plenoptic PIV is an emerging 3D diagnostic that exploits the light-field imaging capabilities of a plenoptic camera. Plenoptic cameras utilize a microlens array to measure the position and angle of light rays captured by the camera. 3D/3C velocity fields are determined through application of the MART algorithm for volume reconstruction and a conventional 3D cross-correlation PIV algorithm. The RIM facility is a recirculating tunnel with a 62.5% aqueous solution of sodium iodide used as the working fluid. Its resulting index of 1.49 is equal to that of acrylic. Plenoptic PIV was used to measure the 3D velocity field of a turbulent boundary layer flow over a smooth wall, a single wall-mounted hemisphere and a full array of hemispheres (i.e. a rough wall) with a k/ δ ~ 4.6. Preliminary time averaged and instantaneous 3D velocity fields will be presented. This material is based upon work supported by the National Science Foundation under Grant No. 1235726.

  20. Imaging 3D seismic velocity along the seismogenic zone of Algarve region (southern Portugal)

    NASA Astrophysics Data System (ADS)

    Rocha, João.; Bezzeghoud, Mourad; Caldeira, Bento; Dias, Nuno; Borges, José; Matias, Luís.; Dorbath, Catherine; Carrilho, Fernando

    2010-05-01

    The present seismic tomographic study is focused around Algarve region, in South of Portugal. To locate the seismic events and find the local velocity structure of epicentral area, the P and S arrival times at 38 stations are used. The data used in this study were obtained during the Algarve campaign which worked from January/2006 to July/2007. The preliminary estimate of origin times and hypocentral coordinates are determined by the Hypoinverse program. Linearized inversion procedure was applied to comprise the following two steps: 1) finding the minimum 1D velocity model using Velest and 2) simultaneous relocation of hypocenters and determination of local velocity structure. The velocity model we have reached is a 10 layer model which gave the lowest RMS, after several runnings of eight different velocity models that we used "a priori". The model parameterization assumes a continuous velocity field between 4.5 km/s and 7.0 km/s until 30 km depth. The earth structure is represented in 3D by velocity at discrete points, and velocity at any intervening point is determined by linear interpolation among the surrounding eight grid points. A preliminary analysis of the resolution capabilities of the dataset, based on the Derivative Weight Sum (DWS) distribution, shows that the velocity structure is better resolved in the West part of the region between the surface to15 km. The resulting tomographic image has a prominent low-velocity anomaly that shows a maximum decrease in P-wave velocity in the first 12 kms in the studied region. We also identified the occurrence of local seismic events of reduced magnitude not catalogued, in the neighbourhood of Almodôvar (low Alentejo). The spatial distribution of epicentres defines a NE-SW direction that coincides with the strike of the mapped geological faults of the region and issued from photo-interpretation. Is still expectable to refine the seismicity of the region of Almodôvar and establish more rigorously its role in the

  1. Effects of 3D random correlated velocity perturbations on predicted ground motions

    USGS Publications Warehouse

    Hartzell, S.; Harmsen, S.; Frankel, A.

    2010-01-01

    Three-dimensional, finite-difference simulations of a realistic finite-fault rupture on the southern Hayward fault are used to evaluate the effects of random, correlated velocity perturbations on predicted ground motions. Velocity perturbations are added to a three-dimensional (3D) regional seismic velocity model of the San Francisco Bay Area using a 3D von Karman random medium. Velocity correlation lengths of 5 and 10 km and standard deviations in the velocity of 5% and 10% are considered. The results show that significant deviations in predicted ground velocities are seen in the calculated frequency range (≤1 Hz) for standard deviations in velocity of 5% to 10%. These results have implications for the practical limits on the accuracy of scenario ground-motion calculations and on retrieval of source parameters using higher-frequency, strong-motion data.

  2. The use of harmonics in 3-D magnetic fields

    SciTech Connect

    Caspi, S.; Helm, M.; Laslett, L.J.

    1993-09-01

    Motivated by the need for new means for specification and determination of 3-D fields that are produced by electromagnetic lens elements in the region interior to coil windings and seeking to obtain techniques that will be convenient for accurate conductor placement and dynamical study of particle motion, the authors have generalized the representation of a 2-D magnetic field to 3-D. They have shown that the 3-D magnetic field components of a multipole magnet in the curl-free divergence-free region near the axis r = 0 can be derived from one dimensional functions A{sub n}(z) and their derivatives. In this report they apply both methods to the ``end`` region of a 40 mm bore SSC quadrupole, calculating first the field harmonics and then reconstructing the field comparing both results with direct Biot-Savart calculation.

  3. Texture splats for 3D vector and scalar field visualization

    SciTech Connect

    Crawfis, R.A.; Max, N.

    1993-04-06

    Volume Visualization is becoming an important tool for understanding large 3D datasets. A popular technique for volume rendering is known as splatting. With new hardware architectures offering substantial improvements in the performance of rendering texture mapped objects, we present textured splats. An ideal reconstruction function for 3D signals is developed which can be used as a texture map for a splat. Extensions to the basic splatting technique are then developed to additionally represent vector fields.

  4. Using Adjoint Methods to Improve 3-D Velocity Models of Southern California

    NASA Astrophysics Data System (ADS)

    Liu, Q.; Tape, C.; Maggi, A.; Tromp, J.

    2006-12-01

    We use adjoint methods popular in climate and ocean dynamics to calculate Fréchet derivatives for tomographic inversions in southern California. The Fréchet derivative of an objective function χ(m), where m denotes the Earth model, may be written in the generic form δχ=int Km(x) δln m(x) d3x, where δln m=δ m/m denotes the relative model perturbation. For illustrative purposes, we construct the 3-D finite-frequency banana-doughnut kernel Km, corresponding to the misfit of a single traveltime measurement, by simultaneously computing the 'adjoint' wave field s† forward in time and reconstructing the regular wave field s backward in time. The adjoint wave field is produced by using the time-reversed velocity at the receiver as a fictitious source, while the regular wave field is reconstructed on the fly by propagating the last frame of the wave field saved by a previous forward simulation backward in time. The approach is based upon the spectral-element method, and only two simulations are needed to produce density, shear-wave, and compressional-wave sensitivity kernels. This method is applied to the SCEC southern California velocity model. Various density, shear-wave, and compressional-wave sensitivity kernels are presented for different phases in the seismograms. We also generate 'event' kernels for Pnl, S and surface waves, which are the Fréchet kernels of misfit functions that measure the P, S or surface wave traveltime residuals at all the receivers simultaneously for one particular event. Effectively, an event kernel is a sum of weighted Fréchet kernels, with weights determined by the associated traveltime anomalies. By the nature of the 3-D simulation, every event kernel is also computed based upon just two simulations, i.e., its construction costs the same amount of computation time as an individual banana-doughnut kernel. One can think of the sum of the event kernels for all available earthquakes, called the 'misfit' kernel, as a graphical

  5. Imaging 3D strain field monitoring during hydraulic fracturing processes

    NASA Astrophysics Data System (ADS)

    Chen, Rongzhang; Zaghloul, Mohamed A. S.; Yan, Aidong; Li, Shuo; Lu, Guanyi; Ames, Brandon C.; Zolfaghari, Navid; Bunger, Andrew P.; Li, Ming-Jun; Chen, Kevin P.

    2016-05-01

    In this paper, we present a distributed fiber optic sensing scheme to study 3D strain fields inside concrete cubes during hydraulic fracturing process. Optical fibers embedded in concrete were used to monitor 3D strain field build-up with external hydraulic pressures. High spatial resolution strain fields were interrogated by the in-fiber Rayleigh backscattering with 1-cm spatial resolution using optical frequency domain reflectometry. The fiber optics sensor scheme presented in this paper provides scientists and engineers a unique laboratory tool to understand the hydraulic fracturing processes in various rock formations and its impacts to environments.

  6. 3D Magnetotelluic characterization of the Coso GeothermalField

    SciTech Connect

    Newman, Gregory A.; Hoversten, G. Michael; Wannamaker, Philip E.; Gasperikova, Erika

    2007-04-23

    -dimensional conductivitymodel. Initial analysis of the Coso MT data was carried out using 2D MTimaging. An initial 3D conductivity model was constructed from a seriesof 2D resistivity images obtained using the inline electric fieldmeasurements (Zyx impedance elements) along several measurementtransects. This model was then refined through a 3D inversion process.This model shows the controlling geological structures possiblyinfluencing well production at Coso and correlations with mapped surfacefeatures such as faults and regional geoelectric strike. The 3D modelalso illustrates the refinement in positioning of conductivity contactswhen compared to isolated 2D inversion transects. The conductivity modelhas also been correlated with microearthquake locations, well fluidproduction intervals and most importantly with an acoustic and shearvelocity model derived by Wu and Lees (1999). This later correlationshows the near-vertical high conductivity structure on the eastern flankof the producing field is also a zone of increased acoustic velocity andincreased Vp/Vs ratio bounded by mapped fault traces. South of theDevil's Kitchen is an area of high geothermal well density, where highlyconductive near surface material is interpreted as a clay cap alterationzone manifested from the subsurface geothermal fluids and relatedgeochemistry. Beneath the clay cap, however, the conductivity isnondescript, whereas the Vp/Vs ratio is enhanced over the productionintervals. It is recommended that more MT data sites be acquired to thesouthwest of the Devil's Kitchen area to better refine the conductivitymodel in that area.

  7. 3D Magnetotelluric characterization of the COSO GeothermalField

    SciTech Connect

    Newman, Gregory A.; Hoversten, Michael; Gasperikova, Erika; Wannamaker, Philip E.

    2005-01-01

    Knowledge of the subsurface electrical resistivity/conductivity can contribute to a better understanding of complex hydrothermal systems, typified by Coso geothermal field, through mapping the geometry (bounds and controlling structures) over existing production. Three-dimensional magnetotelluric (MT) inversion is now an emerging technology for characterizing the resistivity structures of complex geothermal systems. The method appears to hold great promise, but histories exploiting truly 3D inversion that demonstrate the advantages that can be gained by acquiring and analyzing MT data in three dimensions are still few in number. This project will address said issue, by applying 3D MT forward modeling and inversion to a MT data set acquired over the Coso geothermal field. The goal of the project is to provide the capability to image large geothermal reservoirs in a single self-consistent model. Initial analysis of the Coso MT data has been carried out using 2D MT imaging technology to construct an initial 3D resistivity model from a series of 2D resistivity images obtained using the inline electric field measurements (Zxy impedance elements) along different measurement transects. This model will be subsequently refined through a 3D inversion process. The initial 3D resistivity model clearly shows the controlling geological structures possibly influencing well production at Coso. The field data however, also show clear three dimensionality below 1 Hz, demonstrating the limitations of 2D resistivity imaging. The 3D MT predicted data arising from this starting model show good correspondence in dominant components of the impedance tensor (Zxy and Zyx) above 1Hz. Below 1 Hz there is significant differences between the field data and the 2D model data.

  8. Electric field in 3D gravity with torsion

    SciTech Connect

    Blagojevic, M.; Cvetkovic, B.

    2008-08-15

    It is shown that in static and spherically symmetric configurations of the system of Maxwell field coupled to 3D gravity with torsion, at least one of the Maxwell field components has to vanish. Restricting our attention to the electric sector of the theory, we find an interesting exact solution, corresponding to the azimuthal electric field. Its geometric structure is to a large extent influenced by the values of two different central charges, associated to the asymptotic AdS structure of spacetime.

  9. 3D P-Wave Velocity Structure of the Deep Galicia Rifted Margin

    NASA Astrophysics Data System (ADS)

    Bayrakci, Gaye; Minshull, Timothy; Davy, Richard; Sawyer, Dale; Klaeschen, Dirk; Papenberg, Cord; Reston, Timothy; Shillington, Donna; Ranero, Cesar

    2015-04-01

    The combined wide-angle reflection-refraction and multi-channel seismic (MCS) experiment, Galicia 3D, was carried out in 2013 at the Galicia rifted margin in the northeast Atlantic Ocean, west of Spain. The main geological features within the 64 by 20 km (1280 km²) 3D box investigated by the survey are the peridotite ridge (PR), the fault bounded, rotated basement blocks and the S reflector, which has been interpreted to be a low angle detachment fault. 44 short period four-component ocean bottom seismometers and 28 ocean bottom hydrophones were deployed in the 3D box. 3D MCS profiles sampling the whole box were acquired with two airgun arrays of 3300 cu.in. fired alternately every 37.5 m. We present the results from 3D first-arrival time tomography that constrains the P-wave velocity in the 3D box, for the entire depth sampled by reflection data. Results are validated by synthetic tests and by the comparison with Galicia 3D MCS lines. The main outcomes are as follows: 1- The 3.5 km/s iso-velocity contour mimics the top of the acoustic basement observed on MCS profiles. Block bounding faults are imaged as velocity contrasts and basement blocks exhibit 3D topographic variations. 2- On the southern profiles, the top of the PR rises up to 5.5 km depth whereas, 20 km northward, its basement expression (at 6.5 km depth) nearly disappears. 3- The 6.5 km/s iso-velocity contour matches the topography of the S reflector where the latter is visible on MCS profiles. Within a depth interval of 0.6 km (in average), velocities beneath the S reflector increase from 6.5 km/s to 7 km/s, which would correspond to a decrease in the degree of serpentinization from ~45 % to ~30 % if these velocity variations are caused solely by variations in hydration. At the intersections between the block bounding normal faults and the S reflector, this decrease happens over a larger depth interval (> 1 km), suggesting that faults act as conduit for the water flow in the upper mantle.

  10. 3D Hole Inspection Using Lens with High Field Curvature

    NASA Astrophysics Data System (ADS)

    Zavyalov, Petr

    2015-02-01

    One of the actual 3D measurement problems is the optical inspection of various holes. In this respect, the task of plane image formation of holes as extended 3D objects using optical methods turns out to be of primary importance. We have developed specialized lenses that perform such transformations due to specially increased aberrations (field curvature, astigmatism) for the formation of extended objects plane images. The calculations of the lens parameters are presented. The detail analysis of the imaging properties was carried out. The presented hole inspection lens has been designed, constructed and used for inspection of the fuel assembly spacer grids.

  11. A 3-D measurement of biomagnetic field and its application

    NASA Astrophysics Data System (ADS)

    Uchikawa, Yoshinori; Kim, Bong-Soo; Kobayashi, Koichiro

    2006-09-01

    This review paper focuses in the usefulness of three-dimensional (3-D) biomagnetic field measurement for discriminating multiple sources closely located and overlapped in time. We have developed a 3-D second-order gradiometer connected to 39-channel SQUIDs for vector measurement of magnetoencephalogram (MEG), which can simultaneously detect magnetic field components perpendicular and tangential to the scalp. To assess discrimination and separation of multiple sources overlapping in time, we showed both simulation study and 3-D vector measurement of MEG as following; (a) mixed auditory evoked field (AEF) and somatosensory evoked field (SEF), (b) separating second somatosensory (SII) activity from primary somatosensory (SI) activity in SEF. The magnetic field distribution perpendicular to the scalp was not helpful for estimating the location and number of sources, owing to the lack of a dipole pattern, but the magnetic field distribution tangential to the scalp can provide information about new constraint conditions by visual inspection and singular value decomposition (SVD) method. We estimated multiple sources of mixed AEF and SEF from the MEG data of the magnetic field tangential to the scalp, and also estimated multiple sources of SI and SII activity. These results were confirmed by comparison with superimposed source locations in MRI of subject's head.

  12. 3-D Numerical Field Calculations of CESR's Upgraded Superconducting Magnets

    NASA Astrophysics Data System (ADS)

    Greenwald, Zipi; Greenwald, Shlomo

    1997-05-01

    A 3-D numerical code( Z. Greenwald, ``BST.c 3-D Magnetic Field Calculation Numerical Code'', Cornell University Note 96-09) was used to calculate the spatial magnetic fields generated by a current carrying wire. In particular, the code calculates the fields of wire loops wrapped on a pipe similar to superconductive magnet structures. The arrangement and dimensions of the loops can be easily modified to create dipoles, quadrupoles, skew magnets etc., and combinations of the above. In this paper we show the calculated 3-D fields of ironless superconducting quadrupole dipole combination designed for CESR phase III upgrade (which will be manufactured by TESLA). Since the magnet poles are made of loops, the fields at the edges are not only distorted but have a component, B_z, in the z direction as well. This Bz field can cause X-Y coupling of the beam. In order to calculate the coupling, the particle trajectories through the whole magnet were computed. The code is also used to calculate local fields errors due to possible manufacturing imperfections. An example of a rotational error of one pole, and an example of an error in the winding width are shown.

  13. 3-D P Wave Velocity Structure of Marmara Region Using Local Earthquake Tomography

    NASA Astrophysics Data System (ADS)

    Işık, S. E.; Gurbuz, C.

    2014-12-01

    The 3D P wave velocity model of upper and lower crust of the Marmara Region between 40.200- 41.200N and 26.500- 30.500E is obtained by tomographic inversion (Simulps) of 47034 P wave arrivals of local earthquakes recorded at 90 land stations between October 2009 and December 2012 and 30 OBO stations and 14162 shot arrivals recorded at 35 OBO stations (Seismarmara Survey, 2001). We first obtained a 1D minimum model with Velest code in order to obtain an initial model for 3D inversion with 648 well located earthquakes located within the study area. After several 3D inversion trials we decided to create a more adequate initial model for 3D inversion. Choosing the initial model we estimated the 3D P wave velocity model representing the whole region both for land and sea. The results are tested by making Checkerboard , Restoring Resolution and Characteristic Tests, and the reliable areas of the resulting model is defined in terms of RDE, DWS, SF and Hit count distributions. By taking cross sections from the resulting model we observed the vertical velocity change along profiles crossing both land and sea. All the profiles crossing the basins showed that the high velocities of lower crust make extensions towards the basin area which looks like the force that gives a shape to the basins. These extensions of lower crust towards the basins appeared with an average velocity of 6.3 km/s which might be the result of the deformation due the shearing in the region. It is also interpreted that the development of these high velocities coincide with the development of the basins. Thus, both the basins and the high velocity zones around them might be resulted from the entrance of the NAF into the Marmara Sea and at the same time a shear regime was dominated due to the resistance of the northern Marmara Region (Yılmaz, 2010). The seismicity is observed between 5 km and 15 km after the 3D location of the earthquakes. The locations of the earthquakes improved and the seismogenic zone

  14. Effect of postural changes on 3D joint angular velocity during starting block phase.

    PubMed

    Slawinski, Jean; Dumas, Raphaël; Cheze, Laurence; Ontanon, Guy; Miller, Christian; Mazure-Bonnefoy, Alice

    2013-01-01

    Few studies have focused on the effect of posture during sprint start. The aim of this study was to measure the effect of the modification of horizontal distance between the blocks during sprint start on three dimensional (3D) joint angular velocity. Nine trained sprinters started using three different starting positions (bunched, medium and elongated). They were equipped with 63 passive reflective markers, and an opto-electronic Motion Analysis system was used to collect the 3D marker trajectories. During the pushing phase on the blocks, norm of the joint angular velocity (NJAV), 3D Euler angular velocity (EAV) and pushing time on the blocks were calculated. The results demonstrated that the decrease of the block spacing induces an opposite effect on the angular velocity of joints of the lower and the upper limbs. The NJAV of the upper limbs is greater in the bunched start, whereas the NJAV of the lower limbs is smaller. The modifications of NJAV were due to a combination of the movement of the joints in the different degrees of freedom. The medium start seems to be the best compromise because it leads, in a short pushing time, to a combination of optimal joint velocities for upper and lower segments. PMID:23062070

  15. UCVM: Open Source Software for Understanding and Delivering 3D Velocity Models

    NASA Astrophysics Data System (ADS)

    Gill, D.; Small, P.; Maechling, P. J.; Jordan, T. H.; Shaw, J. H.; Plesch, A.; Chen, P.; Lee, E. J.; Taborda, R.; Olsen, K. B.; Callaghan, S.

    2014-12-01

    Physics-based ground motion simulations can calculate the propagation of earthquake waves through 3D velocity models of the Earth. The Southern California Earthquake Center (SCEC) has developed the Unified Community Velocity Model (UCVM) framework to help researchers build structured or unstructured velocity meshes from 3D velocity models for use in wave propagation simulations. The UCVM software framework makes it easy to extract P and S wave propagation speeds and other material properties from 3D velocity models by providing a common interface through which researchers can query earth models for a given location and depth. Currently, the platform supports multiple California models, including SCEC CVM-S4 and CVM-H 11.9.1, and has been designed to support models from any region on earth. UCVM is currently being use to generate velocity meshes for many SCEC wave propagation codes, including AWP-ODC-SGT and Hercules. In this presentation, we describe improvements to the UCVM software. The current version, UCVM 14.3.0, released in March of 2014, supports the newest Southern California velocity model, CVM-S4.26, which was derived from 26 full-3D tomographic iterations using CVM-S4 as the starting model (Lee et al., this meeting), and the Broadband 1D velocity model used in the CyberShake 14.2 study. We have ported UCVM to multiple Linux distributions and OS X. Also included in this release is the ability to add small-scale stochastic heterogeneities to extract Cartesian meshes for use in high-frequency ground motion simulations. This tool was built using the C language open-source FFT library, FFTW. The stochastic parameters (Hurst exponent, correlation length, and the horizontal/vertical aspect ratio) can be customized by the user. UCVM v14.3.0 also provides visualization scripts for constructing cross-sections, horizontal slices, basin depths, and Vs30 maps. The interface allows researchers to visually review velocity models . Also, UCVM v14.3.0 can extract

  16. UCVM: An Open Source Software Package for Querying and Visualizing 3D Velocity Models

    NASA Astrophysics Data System (ADS)

    Gill, D.; Small, P.; Maechling, P. J.; Jordan, T. H.; Shaw, J. H.; Plesch, A.; Chen, P.; Lee, E. J.; Taborda, R.; Olsen, K. B.; Callaghan, S.

    2015-12-01

    Three-dimensional (3D) seismic velocity models provide foundational data for ground motion simulations that calculate the propagation of earthquake waves through the Earth. The Southern California Earthquake Center (SCEC) has developed the Unified Community Velocity Model (UCVM) package for both Linux and OS X. This unique framework provides a cohesive way for querying and visualizing 3D models. UCVM v14.3.0, supports many Southern California velocity models including CVM-S4, CVM-H 11.9.1, and CVM-S4.26. The last model was derived from 26 full-3D tomographic iterations on CVM-S4. Recently, UCVM has been used to deliver a prototype of a new 3D model of central California (CCA) also based on full-3D tomographic inversions. UCVM was used to provide initial plots of this model and will be used to deliver CCA to users when the model is publicly released. Visualizing models is also possible with UCVM. Integrated within the platform are plotting utilities that can generate 2D cross-sections, horizontal slices, and basin depth maps. UCVM can also export models in NetCDF format for easy import into IDV and ParaView. UCVM has also been prototyped to export models that are compatible with IRIS' new Earth Model Collaboration (EMC) visualization utility. This capability allows for user-specified horizontal slices and cross-sections to be plotted in the same 3D Earth space. UCVM was designed to help a wide variety of researchers. It is currently being use to generate velocity meshes for many SCEC wave propagation codes, including AWP-ODC-SGT and Hercules. It is also used to provide the initial input to SCEC's CyberShake platform. For those interested in specific data points, the software framework makes it easy to extract P and S wave propagation speeds and other material properties from 3D velocity models by providing a common interface through which researchers can query earth models for a given location and depth. Also included in the last release was the ability to add small

  17. Effects of 3D Velocity and Attenuation in the Tonga-Fiji Subduction Zone

    NASA Astrophysics Data System (ADS)

    Savage, B.; Wiens, D. A.; Tromp, J.

    2005-12-01

    The current understanding of a subduction zone's temperature and composition is limited. Much of our recent knowledge of subduction zones comes from earthquake locations, geochemical measurements, and lab based experiments. Recently, two studies of the Tonga-Fiji subduction zone have presented tomographic images of velocity and attenuation (Roth et al., 1999; Zhao et al., 1997). Roth et al. (2000) then combined these two tomographic models of the Tonga-Fiji subduction zone to derive an empirical relationship between changes in velocity and attenuation. This relationship agrees well with two independent, experimental data sets (Jackson et al., 1992; Sato et al., 1989). Using the tomographic velocity model and the empirical relationship between velocity and attenuation we create synthetic seismograms for the Tonga-Fiji subduction zone to test whether a simple increase in velocity accurately depicts this subduction zone. To construct the model we use the tomographic model of Zhao et al. (1997) to create a shear velocity model using a simple Vs/Vp ratio. Following Roth et al. (2000) these tomographic models are combined with the empirical relation between velocity and attenuation to create an attenuation model. The resulting synthetics are compared to recorded data to validate the tomographic velocity model and the empirical relation between velocity and attenuation. Any mismatch in this comparison will provide a basis for further refinement of the tomographic models and the velocity-attenuation relation. The synthetics are created using the SPECFEM3D global code (Komatitsch et al., 2002) with the new addition of a three-dimensional attenuation operator. Attenuation is simulated by a set of standard linear solids over the desired frequency range as described in Liu et al. (1976). Our initial results at a minimum period of 3.3 seconds suggest that the attenuation structure plays a minor role for the present source-receiver geometry. The addition of the 3D attenuation

  18. 3D temperature field reconstruction using ultrasound sensing system

    NASA Astrophysics Data System (ADS)

    Liu, Yuqian; Ma, Tong; Cao, Chengyu; Wang, Xingwei

    2016-04-01

    3D temperature field reconstruction is of practical interest to the power, transportation and aviation industries and it also opens up opportunities for real time control or optimization of high temperature fluid or combustion process. In our paper, a new distributed optical fiber sensing system consisting of a series of elements will be used to generate and receive acoustic signals. This system is the first active temperature field sensing system that features the advantages of the optical fiber sensors (distributed sensing capability) and the acoustic sensors (non-contact measurement). Signals along multiple paths will be measured simultaneously enabled by a code division multiple access (CDMA) technique. Then a proposed Gaussian Radial Basis Functions (GRBF)-based approach can approximate the temperature field as a finite summation of space-dependent basis functions and time-dependent coefficients. The travel time of the acoustic signals depends on the temperature of the media. On this basis, the Gaussian functions are integrated along a number of paths which are determined by the number and distribution of sensors. The inversion problem to estimate the unknown parameters of the Gaussian functions can be solved with the measured times-of-flight (ToF) of acoustic waves and the length of propagation paths using the recursive least square method (RLS). The simulation results show an approximation error less than 2% in 2D and 5% in 3D respectively. It demonstrates the availability and efficiency of our proposed 3D temperature field reconstruction mechanism.

  19. Numerical Optimization Strategy for Determining 3D Flow Fields in Microfluidics

    NASA Astrophysics Data System (ADS)

    Eden, Alex; Sigurdson, Marin; Mezic, Igor; Meinhart, Carl

    2015-11-01

    We present a hybrid experimental-numerical method for generating 3D flow fields from 2D PIV experimental data. An optimization algorithm is applied to a theory-based simulation of an alternating current electrothermal (ACET) micromixer in conjunction with 2D PIV data to generate an improved representation of 3D steady state flow conditions. These results can be used to investigate mixing phenomena. Experimental conditions were simulated using COMSOL Multiphysics to solve the temperature and velocity fields, as well as the quasi-static electric fields. The governing equations were based on a theoretical model for ac electrothermal flows. A Nelder-Mead optimization algorithm was used to achieve a better fit by minimizing the error between 2D PIV experimental velocity data and numerical simulation results at the measurement plane. By applying this hybrid method, the normalized RMS velocity error between the simulation and experimental results was reduced by more than an order of magnitude. The optimization algorithm altered 3D fluid circulation patterns considerably, providing a more accurate representation of the 3D experimental flow field. This method can be generalized to a wide variety of flow problems. This research was supported by the Institute for Collaborative Biotechnologies through grant W911NF-09-0001 from the U.S. Army Research Office.

  20. Advancing the field of 3D biomaterial printing.

    PubMed

    Jakus, Adam E; Rutz, Alexandra L; Shah, Ramille N

    2016-02-01

    3D biomaterial printing has emerged as a potentially revolutionary technology, promising to transform both research and medical therapeutics. Although there has been recent progress in the field, on-demand fabrication of functional and transplantable tissues and organs is still a distant reality. To advance to this point, there are two major technical challenges that must be overcome. The first is expanding upon the limited variety of available 3D printable biomaterials (biomaterial inks), which currently do not adequately represent the physical, chemical, and biological complexity and diversity of tissues and organs within the human body. Newly developed biomaterial inks and the resulting 3D printed constructs must meet numerous interdependent requirements, including those that lead to optimal printing, structural, and biological outcomes. The second challenge is developing and implementing comprehensive biomaterial ink and printed structure characterization combined with in vitro and in vivo tissue- and organ-specific evaluation. This perspective outlines considerations for addressing these technical hurdles that, once overcome, will facilitate rapid advancement of 3D biomaterial printing as an indispensable tool for both investigating complex tissue and organ morphogenesis and for developing functional devices for a variety of diagnostic and regenerative medicine applications. PMID:26752507

  1. Analysis of the rupture process of the 1995 Kobe earthquake using a 3D velocity structure

    NASA Astrophysics Data System (ADS)

    Guo, Yujia; Koketsu, Kazuki; Ohno, Taichi

    2013-12-01

    A notable feature of the 1995 Kobe (Hyogo-ken Nanbu) earthquake is that violent ground motions occurred in a narrow zone. Previous studies have shown that the origin of such motions can be explained by the 3D velocity structure in this zone. This indicates not only that the 3D velocity structure significantly affects strong ground motions, but also that we should consider its effects in order to determine accurately the rupture process of the earthquake. Therefore, we have performed a joint source inversion of strong-motion, geodetic, and teleseismic data, where 3D Green's functions were calculated for strong-motion and geodetic data in the Osaka basin. Our source model estimates the total seismic moment to be about 2.1 × 1019 N m and the maximum slip reaches 2.9 m near the hypocenter. Although the locations of large slips are similar to those reported by Yoshida et al. (1996), there are quantitative differences between our results and their results due to the differences between the 3D and 1D Green's functions. We have also confirmed that our source model realized a better fit to the strong motion observations, and a similar fit as Yoshida et al. (1996) to the observed static displacements.

  2. Effect of catheter placement on 3-D velocity profiles in curved tubes resembling the human coronary system.

    PubMed

    Krams, R; Wentzel, J J; Cespedes, I; Vinke, R; Carlier, S; van der Steen, A F; Lancee, C T; Slager, C J

    1999-06-01

    Novel measurement techniques based on intravenous ultrasound (IVUS) technology ('IVUS-Flowmetry') require the location of a catheter inside the coronary bed. The present study quantifies disturbances in the 3-D velocity profile induced by catheter placement inside a tube, applying computational fluid dynamics. Two curved, circular meshes (radius K = 0.025 m and K = 0.035 m) with and without a catheter inside the lumen were applied. The catheter was located at the inner curve, the outer curve and at the top position. Boundary conditions were: no slip on the wall, zero stress at the outlet, uniform inflow with entrance velocities of 0.1, 0.2 and 0.4 m/s. Curvature-associated centrifugal forces shifted the maximal velocity to the outer curve and introduced two symmetrical vortices. Additional catheter placement redistributed the 3-D axial velocity field away from the catheter, which was accompanied by the appearance of multiple low-strength vortices. In addition, peak axial velocity increased, peak secondary velocities decreased, axial pressure drop increased and shear stress increased. Flow calculations simulated to resemble IVUS-based flowmetry changed by only 1% after considering secondary velocity. In conclusion, placement of a catheter inside a curved tube resembling the human coronary system changes the velocity field and reduces secondary patterns. The present study supports the usefulness of catheter-based flowmetry during resting flow conditions. During hyperemic flow conditions, flow measurements might be accompanied by large axial pressure drops because the catheter, itself, might act as a significant stenosis. PMID:10414897

  3. 3D Simulation of Velocity Profile of Turbulent Flow in Open Channel with Complex Geometry

    NASA Astrophysics Data System (ADS)

    Kamel, Benoumessad; Ilhem, Kriba; Ali, Fourar; Abdelbaki, Djebaili

    Simulation of open channel flow or river flow presents unique challenge to numerical simulators, which is widely used in the applications of computational fluid dynamics. The prediction is extremely difficult because the flow in open channel is usually transient and turbulent, the geometry is irregular and curved, and the free-surface elevation is varying with time. The results from a 3D non-linear k- ɛ turbulence model are presented to investigate the flow structure, the velocity distribution and mass transport process in a meandering compound open channel and a straight open channel. The 3D numerical model for calculating flow is set up in cylinder coordinates in order to calculate the complex boundary channel. The finite volume method is used to disperse the governing equations and the SIMPLE algorithm is applied to acquire the coupling of velocity and pressure. The non-linear k- ɛ turbulent model has good useful value because of taking into account the anisotropy and not increasing the computational time. The main contributions of this study are developing a numerical method that can be applied to predict the flow in river bends with various bend curvatures and different width-depth ratios. This study demonstrates that the 3D non-linear k- ɛ turbulence model can be used for analyzing flow structures, the velocity distribution and pollutant transport in the complex boundary open channel, this model is applicable for real river and wetland problem.

  4. R3D: Reduction Package for Integral Field Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sánchez, Sebastián. F.

    2011-06-01

    R3D was developed to reduce fiber-based integral field spectroscopy (IFS) data. The package comprises a set of command-line routines adapted for each of these steps, suitable for creating pipelines. The routines have been tested against simulations, and against real data from various integral field spectrographs (PMAS, PPAK, GMOS, VIMOS and INTEGRAL). Particular attention is paid to the treatment of cross-talk. R3D unifies the reduction techniques for the different IFS instruments to a single one, in order to allow the general public to reduce different instruments data in an homogeneus, consistent and simple way. Although still in its prototyping phase, it has been proved to be useful to reduce PMAS (both in the Larr and the PPAK modes), VIMOS and INTEGRAL data. The current version has been coded in Perl, using PDL, in order to speed-up the algorithm testing phase. Most of the time critical algorithms have been translated to C[float=][/float], and it is our intention to translate all of them. However, even in this phase R3D is fast enough to produce valuable science frames in reasonable time.

  5. Widespread 3D seismic survey covers mature field in Gabon

    SciTech Connect

    Riley, D.; Fleming, M. ); Delvaux, J. )

    1993-12-06

    The exploration potential of the Port Gentil region, characterized by some of the earliest petroleum discoveries in Gabon, continues to be of important interest today. Available seismic data are of an older vintage (1974--82), recorded with low common mid-point (CMP) fold. They are critically void of coverage through the transition zone. The geology is highly complex, characterized by salt structures and strong tectonic activity. An intensive joint exploration and reservoir definition campaign is crucial to full evaluation of this area. This article describes the 3D survey conducted during 1992 and early 1993 over a mature oil field in an around Port Gentil and incorporating elements of land, transition zone, and shallow marine data acquisition -- the 3D Mandji program.

  6. 3D deformation field throughout the interior of materials.

    SciTech Connect

    Jin, Huiqing; Lu, Wei-Yang

    2013-09-01

    This report contains the one-year feasibility study for our three-year LDRD proposal that is aimed to develop an experimental technique to measure the 3D deformation fields inside a material body. In this feasibility study, we first apply Digital Volume Correlation (DVC) algorithm to pre-existing in-situ Xray Computed Tomography (XCT) image sets with pure rigid body translation. The calculated displacement field has very large random errors and low precision that are unacceptable. Then we enhance these tomography images by setting threshold of the intensity of each slice. DVC algorithm is able to obtain accurate deformation fields from these enhanced image sets and the deformation fields are consistent with the global mechanical loading that is applied to the specimen. Through this study, we prove that the internal markers inside the pre-existing tomography images of aluminum alloy can be enhanced and are suitable for DVC to calculate the deformation field throughout the material body.

  7. Targeted infill drilling at Stratton field using 3-D seismic

    SciTech Connect

    Suydam, J.R.; Reitz, D.T.

    1994-12-31

    Stratton field is located on the Vicksburg flexure trend in Nueces and Kleberg Counties, South Texas. It has produced more than 2.8 Tcf of gas since 1937 from Frio fluvial/deltaic sandstones and Vicksburg shallow-marine sandstones. The field is a combination stratigraphic and faulted structural trap, and contains numerous highly compartmentalized sandstone reservoirs. Continuous infield drilling is required to keep the field producing, and 3-D seismic data have been used to select the best locations for these wells. In 1992, an 8-mi{sup 2} seismic survey was completed in the southern end of the field, and the resulting structural interpretation presented many more fault traps than were apparent in the 2-D seismic interpretation. So far, all of the new wells drilled within the survey have encountered untapped compartments enclosed by fault traps. Furthermore, fault cuts in the new wells have always been within 20 ft of the position predicted by seismic data.

  8. Targeted infill drilling at Stratton Field using 3-D seismic

    SciTech Connect

    Suydam, J.; Reitz, D.

    1994-09-01

    Stratton field is located on the Vicksburg flexure trend in Nueces and Kleberg counties, south Texas. It has produced over 2.8 tcf of gas since 1937 from Frio fluvial/deltaic sandstones and Vicksburg shallow marine sandstones. The field is a combination stratigraphic and faulted structural trap, and contains numerous highly compartmentalized sandstone reservoirs. Continuous infield drilling is required to keep the field producing, and 3-D seismic data have been used to select the best locations for these wells. In 1992, the Bureau of Economic Geology shot an 8-mi{sup 2} survey in the southern end of the field, and the resulting structural interpretation presented many more fault traps that were not apparent in the 2-D seismic interpretation. So far, all of the new wells drilled within the survey have encountered untapped compartments enclosed by fault traps. Furthermore, fault cuts in the new wells have always been within 20 ft of the position predicted by seismic data.

  9. The 3D Flow Field Around an Embedded Planet

    NASA Astrophysics Data System (ADS)

    Fung, Jeffrey; Artymowicz, Pawel; Wu, Yanqin

    2015-10-01

    3D modifications to the well-studied 2D flow topology around an embedded planet have the potential to resolve long-standing problems in planet formation theory. We present a detailed analysis of the 3D isothermal flow field around a 5 Earth-mass planet on a fixed circular orbit, simulated using our graphics processing unit hydrodynamics code PEnGUIn. We find that, overall, the horseshoe region has a columnar structure extending vertically much beyond the Hill sphere of the planet. This columnar structure is only broken for some of the widest horseshoe streamlines, along which high altitude fluid descends rapidly into the planet’s Bondi sphere, performs one horseshoe turn, and exits the Bondi sphere radially in the midplane. A portion of this flow exits the horseshoe region altogether, which we refer to as the “transient” horseshoe flow. The flow continues as it rolls up into a pair of up-down symmetric horizontal vortex lines shed into the wake of the planet. This flow, unique to 3D, affects both planet accretion and migration. It prevents the planet from sustaining a hydrostatic atmosphere due to its intrusion into the Bondi sphere, and leads to a significant corotation torque on the planet, unanticipated by 2D analysis. In the reported simulation, starting with a {{Σ }}˜ {r}-3/2 radial surface density profile, this torque is positive and partially cancels with the negative differential Lindblad torque, resulting in a factor of three slower planet migration rate. Finally, we report 3D effects can be suppressed by a sufficiently large disk viscosity, leading to results similar to 2D.

  10. Probabilistic Seismic Hazard Maps of Seattle, Washington, Including 3D Sedimentary Basin Effects and Rupture Directivity: Implications of 3D Random Velocity Variations (Invited)

    NASA Astrophysics Data System (ADS)

    Frankel, A. D.; Stephenson, W. J.; Carver, D.; Odum, J.; Williams, R. A.; Rhea, S.

    2010-12-01

    We have produced probabilistic seismic hazard maps of Seattle for 1 Hz spectral acceleration, using over five hundred 3D finite-difference simulations of earthquakes on the Seattle fault, Southern Whidbey Island fault, and Cascadia subduction zone, as well as for random deep and shallow earthquakes at various locations. The 3D velocity model was validated by modeling the observed waveforms for the 2001 M6.8 Nisqually earthquake and several smaller events in the region. At these longer periods (≥ 1 sec) that are especially important to the response of buildings of ten stories or higher, seismic waves are strongly influenced by sedimentary basins and rupture directivity. We are investigating how random spatial variations in the 3D velocity model affect the simulated ground motions for M6.7 earthquakes on the Seattle fault. A fractal random variation of shear-wave velocity with a Von Karman correlation function produces spatial variations of peak ground velocity with multiple scale lengths. We find that a 3D velocity model with a 10% standard deviation in shear-wave velocity in the top 1.5 km and 5% standard deviation from 1.5-10 km depth produces variations in peak ground velocities of as much as a factor of two, relative to the case with no random variations. The model with random variations generally reduces the peak ground velocity of the forward rupture directivity pulse for sites near the fault where basin-edge focusing of S-waves occurs. It also tends to reduce the peak velocity of localized areas where basin surface waves are focused. However, the medium with random variations also causes small-scale amplification of ground motions over distances of a few kilometers. We are also evaluating alternative methods of characterizing the aleatory uncertainty in the probabilistic hazard calculations.

  11. 3-D flame temperature field reconstruction with multiobjective neural network

    NASA Astrophysics Data System (ADS)

    Wan, Xiong; Gao, Yiqing; Wang, Yuanmei

    2003-02-01

    A novel 3-D temperature field reconstruction method is proposed in this paper, which is based on multiwavelength thermometry and Hopfield neural network computed tomography. A mathematical model of multi-wavelength thermometry is founded, and a neural network algorithm based on multiobjective optimization is developed. Through computer simulation and comparison with the algebraic reconstruction technique (ART) and the filter back-projection algorithm (FBP), the reconstruction result of the new method is discussed in detail. The study shows that the new method always gives the best reconstruction results. At last, temperature distribution of a section of four peaks candle flame is reconstructed with this novel method.

  12. A full field, 3-D velocimeter for microgravity crystallization experiments

    NASA Technical Reports Server (NTRS)

    Brodkey, Robert S.; Russ, Keith M.

    1991-01-01

    The programming and algorithms needed for implementing a full-field, 3-D velocimeter for laminar flow systems and the appropriate hardware to fully implement this ultimate system are discussed. It appears that imaging using a synched pair of video cameras and digitizer boards with synched rails for camera motion will provide a viable solution to the laminar tracking problem. The algorithms given here are simple, which should speed processing. On a heavily loaded VAXstation 3100 the particle identification can take 15 to 30 seconds, with the tracking taking less than one second. It seeems reasonable to assume that four image pairs can thus be acquired and analyzed in under one minute.

  13. Probabilistic earthquake location and 3-D velocity models in routine earthquake location

    NASA Astrophysics Data System (ADS)

    Lomax, A.; Husen, S.

    2003-12-01

    Earthquake monitoring agencies, such as local networks or CTBTO, are faced with the dilemma of providing routine earthquake locations in near real-time with high precision and meaningful uncertainty information. Traditionally, routine earthquake locations are obtained from linearized inversion using layered seismic velocity models. This approach is fast and simple. However, uncertainties derived from a linear approximation to a set of non-linear equations can be imprecise, unreliable, or even misleading. In addition, 1-D velocity models are a poor approximation to real Earth structure in tectonically complex regions. In this paper, we discuss the routine location of earthquakes in near real-time with high precision using non-linear, probabilistic location methods and 3-D velocity models. The combination of non-linear, global search algorithms with probabilistic earthquake location provides a fast and reliable tool for earthquake location that can be used with any kind of velocity model. The probabilistic solution to the earthquake location includes a complete description of location uncertainties, which may be irregular and multimodal. We present applications of this approach to determine seismicity in Switzerland and in Yellowstone National Park, WY. Comparing our earthquake locations to earthquake locations obtained using linearized inversion and 1-D velocity models clearly demonstrates the advantages of probabilistic earthquake location and 3-D velocity models. For example, the more complete and reliable uncertainty information of non-linear, probabilistic earthquake location greatly facilitates the identification of poorly constrained hypocenters. Such events are often not identified in linearized earthquake location, since the location uncertainties are determined with a simplified, localized and approximate Gaussian statistic.

  14. 3D velocity structure of upper crust beneath NW Bohemia/Vogtland

    NASA Astrophysics Data System (ADS)

    Javad Fallahi, Mohammad; Mousavi, Sima; Korn, Michael; Sens-Schönfelder, Christoph; Bauer, Klaus; Rößler, Dirk

    2013-04-01

    The 3D structure of the upper crust beneath west Bohemia/Vogtland region, analyzed with travel time tomography and ambient noise surface wave tomography using existing data. This region is characterized by a series of phenomena like occurrence of repeated earthquake swarms, surface exhalation, CO2 enriched fluids, mofettes, mineral springs and enhanced heat flow, and has been proposed as an excellent location for an ICDP drilling project targeted to a better understanding of the crust in an active magmatic environment. We performed a 3D tomography using P-and S-wave travel times of local earthquakes and explosions. The data set were taken from permanent and temporary seismic networks in Germany and Czech Republic from 2000 to 2010, as well as active seismic experiments like Celebration 2000 and quarry blasts. After picking P and S wave arrival times, 399 events which were recorded by 9 or more stations and azimuthal gap<160° were selected for inversion. A simultaneous inversion of P and S wave 1D velocity models together with relocations of hypocenters and station corrections was performed. The obtained minimum 1D velocity model was used as starting model for the 3D Vp and Vp/Vs velocity models. P and S wave travel time tomography employs damped least-square method and ray tracing by pseudo-bending algorithm. For model parametrization different cell node spacings have been tested to evaluate the resolution in each node. Synthetic checkerboard tests have been done to check the structural resolution. Then Vp and Vp/Vs in the preferred 3D grid model have been determined. Earthquakes locations in iteration process change till the hypocenter adjustments and travel time residuals become smaller than the defined threshold criteria. Finally the analysis of the resolution depicts the well resolved features for interpretation. We observed lower Vp/Vs ratio in depth of 5-10 km close to the foci of earthquake swarms and higher Vp/Vs ratio is observed in Saxoturingian zone and

  15. 3-D magnetic field calculations for wiggglers using MAGNUS-3D

    SciTech Connect

    Pissanetzky, S.; Tompkins, P.

    1988-01-01

    The recent but steady trend toward increased magnetic and geometric complexity in the design of wigglers and undulators, of which tapered wigglers, hybrid structures, laced electromagnetic wigglers, magnetic cladding, twisters and magic structures are examples, has caused a need for reliable 3-D computer models and a better understanding of the behavior of magnetic systems in three dimensions. The capabilities of the MAGNUS-3D Group of Programs are ideally suited to solve this class of problems and provide insight into 3-D effects. MAGNUS-3D can solve any problem of Magnetostatics involving permanent magnets, linear or nonlinear ferromagnetic materials and electric conductors of any shape in space. The magnetic properties of permanent magnets are described by the complete nonlinear demagnetization curve as provided by the manufacturer, or, at the user's choice, by a simpler approximation involving the coercive force, the residual induction and the direction of magnetization. The ferromagnetic materials are described by a magnetization table and an accurate interpolation relation. An internal library with properties of common industrial steels is available. The conductors are independent of the mesh and are described in terms of conductor elements from an internal library.

  16. 3-D crustal velocity model for Lithuania and its application to local event studies

    NASA Astrophysics Data System (ADS)

    Budraitis, M.; Kozlovskaya, E.; Janutyte, I.; Motuza, G.

    2009-12-01

    PASSEQ 2006-2008 project (PASsive Seismic Experiment in TESZ) aimed at studying the lithosphere-asthenosphere system around the TransEuropean Suture Zone (TESZ)- the transition between old Proterozoic platform of north and east Europe and younger Phanerozoic platform in central and western Europe. The experiment was a seismic array research aiming to retrieve the structure of the crust and Earth's mantle down to the mantle transition zone, including mapping of upper mantle seismic velocity variations and discontinuities (Moho, lithosphere-asthenosphere boundary, mantle transition zone) using all available techniques. During the experiment 26 seismic stations (including four broadband stations) were installed in Lithuania and operated since June, 2006 till January, 2008. One of the main reasons of PASSEQ deployment in Lithuania is identification and characterisation of the local seismic activity. During the data acquisition period a number of local seismic events was identified and preliminary event location was made using LocSat and VELEST algorithms and 1-D velocity models. These standard procedures is not enough precise for Lithuania, however, because the thickness of the crust varies significantly in the region (from 45 to 55 km). Another problem was low quality of S-wave arrivals due to thick (up to 2 km) sediments in most part of Lithuania. In order to improve event location, we compiled a 3-D seismic velocity model of the crust down to a depth of 60 km. The model, consisting of four major layers (sediments, upper crust, middle crust, lower crust and uppermost mantle) was interpolated from 2-D velocity models along previous wide-angle reflection and refraction profiles into a regular grid. The quality of the approximation was analysed using comparison of travel times of P-waves recorded by controlled source experiments and calculated travel times through the 3-D velocity model. The model was converted into a density model using a special procedure, in which

  17. On the Quality of Velocity Interpolation Schemes for Marker-In-Cell Methods on 3-D Staggered Grids

    NASA Astrophysics Data System (ADS)

    Kaus, B.; Pusok, A. E.; Popov, A.

    2015-12-01

    The marker-in-cell method is generally considered to be a flexible and robust method to model advection of heterogenous non-diffusive properties (i.e. rock type or composition) in geodynamic problems or incompressible Stokes problems. In this method, Lagrangian points carrying compositional information are advected with the ambient velocity field on an immobile, Eulerian grid. However, velocity interpolation from grid points to marker locations is often performed without preserving the zero divergence of the velocity field at the interpolated locations (i.e. non-conservative). Such interpolation schemes can induce non-physical clustering of markers when strong velocity gradients are present (Jenny et al., 2001) and this may, eventually, result in empty grid cells, a serious numerical violation of the marker-in-cell method. Solutions to this problem include: using larger mesh resolutions and/or marker densities, or repeatedly controlling the marker distribution (i.e. inject/delete), but which does not have an established physical background. To remedy this at low computational costs, Jenny et al. (2001) and Meyer and Jenny (2004) proposed a simple, conservative velocity interpolation (CVI) scheme for 2-D staggered grid, while Wang et al. (2015) extended the formulation to 3-D finite element methods. Here, we follow up with these studies and report on the quality of velocity interpolation methods for 2-D and 3-D staggered grids. We adapt the formulations from both Jenny et al. (2001) and Wang et al. (2015) for use on 3-D staggered grids, where the velocity components have different node locations as compared to finite element, where they share the same node location. We test the different interpolation schemes (CVI and non-CVI) in combination with different advection schemes (Euler, RK2 and RK4) and with/out marker control on Stokes problems with strong velocity gradients, which are discretized using a finite difference method. We show that a conservative formulation

  18. Reconstruction of the 3D flow field in a differentially heated rotating annulus laboratory experiment

    NASA Astrophysics Data System (ADS)

    Harlander, U.; Wright, G. B.; Egbers, C.

    2012-04-01

    In the earth's atmosphere baroclinic instability is responsible for the heat and momentum transport from low to high latitudes. In the fifties, Raymond Hide used a rather simple laboratory experiment to study such vortices in the lab. The experiment is comprised by a cooled inner and heated outer cylinder mounted on a rotating platform, which mimics the heated tropical and cooled polar regions of the earth's atmosphere. The experiment shows rich dynamics that have been studied by varying the radial temperature difference and the rate of annulus revolution. At the Brandenburg University of Technology (BTU) Cottbus the differentially heated rotating annulus is a reference experiment of the DFG priority program 'MetStröm'. The 3D structure of the annulus flow field has been numerically simulated but, to our knowledge, has not been measured in the laboratory. In the present paper we use novel interpolation techniques to reconstruct the 3D annulus flow field from synchronous Particle Image Velocimetry (PIV) and Infrared Thermography (IRT) measurements. The PIV system is used to measure the horizontal velocity components at 40, 60, 80, 100, and 120 mm above the bottom. The uppermost level is thus 15 mm below the fluid's surface. The surface temperature is simultaneously measured by an infrared (IR) camera. The PIV and infrared cameras have been mounted above the annulus and they co-rotate with the annulus. From the PIV observations alone a coherent 3D picture of the flow cannot be constructed since the PIV measurements have been taken at different instants of time. Therefore a corresponding IR image has been recorded for each PIV measurement. These IR images can be used to reconstruct the correct phase of the measured velocity fields. Each IR and PIV image for which t>0 is rotated back to the position at t=0. Then all surface waves have the same phase. In contrast, the PIV velocity fields generally have different phases since they have been taken at different vertical

  19. 3d Velocity Tomography of The Kos - Nisyros Volcanic Area - East Aegean Sea

    NASA Astrophysics Data System (ADS)

    Nikolova, S.; Ilinski, D.; Makris, J.; Chonia, T.; Stavrakakis, J.

    Since June 2000, active and passive seismic observations have been carried out by IfG, GeoPro GmbH, Hamburg and Institute of Geodynamics, Athens within the frame of the project GEOWARN (Geo-Spacial Warning Systems Nisyros Volcano, Greece: An Emergency Case Study of the Volcanic Area of Nisyros) supported by the European Community. In the active experiment 48 recording seismic units were deployed and recorded more than 7000 shots in 3D array. The Nisyros volcano has been identified as an apophytic intrusion of much larger volcanic structure with a caldera of 35 km diameter, extending between the southern coasts of the islands of Kos and Nisyros. To obtain 3-D velocity structure of the area a tomographic inversion was made using 6800 rays which probed the area with a very high ray density. The method applied and the high accuracy of active tomographic data allowed to resolve the high velocity bodies in the caldera. The complex volcanic structure is identified by high velocity rocks in- truding through the upper crust and penetrating the volcanic cone to depth of approx. 1.0 km to 1.8 km below the surface. Particularly high velocity bodies were identified below the islands of Yali and the central caldera of Nisyros. The high velocity bodies at shallow depth were interpreted as high-density cumulates of solidified magma intru- sion in the caldera. These intrusions explain very high temperature of 300C observed in the lower aquifer in the caldera at 1.5 km depth as confirmed by drilling. The vol- canic edifices of Kos, Yali, Nisyros and Strongily are part of a major volcanic caldera nearly 35 km in diameter. This size of the volcanic caldera explains the large volume of ignimbrites erupted 160 000 years ago. By combining geodetic, geophysical, geo- chemical and geological observations it is intended to correlate magma movements and associated changes of physical and chemical parameters of the recent volcanism.

  20. A 3-D crustal velocity structure across the southeastern Carpathians of Romania

    NASA Astrophysics Data System (ADS)

    Landes, M.; Hauser, F.; Ritter, J. R. R.; Fielitz, W.; Popa, M.

    2003-04-01

    The Vrancea zone in the southeastern Carpathians is one of the most active seismic regions in Europe. In order to study the crustal and upper-mantle structure in this region, two seismic refraction experiments were carried out in 1999 and 2001. The 1999 campaign comprised a 320 km long N-S profile and a 80 km long transverse profile. All shots were recorded simultaneously on both profiles. The profile conducted in 2001 extended in E-W direction from the Hungarian border across the Vrancea zone to the Black Sea. A first ever 3-D crustal velocity model of the south-eastern Carpathians within a 115 x 235 km wide region around the Vrancea zone is presented. This model was generated by application of a 3-D refraction and reflection tomography algorithm (Hole 1992, 1995). In order to enhance the model resolution, first arrival data from local earthquakes were also included. The results indicate a high-velocity structure above the Vrancea zone extending from shallow levels to depths of about 11 km. A possible relation to the Trotus and Capidava-Ovidiu faults, which converge to the north of it, is deemed unlikely. However,the existence of the outstanding high velocities may be explained by crystalline basement thrust onto the sub-Carpathian nappes. The high-velocity region is surrounded by the lower velocity Focsani and Brasov basins. The sedimentary succession beneath the southern part of the model area extends to 18 km depth, while in the north sediment thickness varies between 10 and 15 km. Further results of the interface modelling of prominent reflections show that the mid-crustal and Moho interfaces shallow northwards from 30 km to 22 km and from 42 km to 38 km, respectively.

  1. Comparative velocity structure of active Hawaiian volcanoes from 3-D onshore-offshore seismic tomography

    USGS Publications Warehouse

    Park, J.; Morgan, J.K.; Zelt, C.A.; Okubo, P.G.; Peters, L.; Benesh, N.

    2007-01-01

    We present a 3-D P-wave velocity model of the combined subaerial and submarine portions of the southeastern part of the Island of Hawaii, based on first-arrival seismic tomography of marine airgun shots recorded by the onland seismic network. Our model shows that high-velocity materials (6.5-7.0??km/s) lie beneath Kilauea's summit, Koae fault zone, and the upper Southwest Rift Zone (SWRZ) and upper and middle East Rift Zone (ERZ), indicative of magma cumulates within the volcanic edifice. A separate high-velocity body of 6.5-6.9??km/s within Kilauea's lower ERZ and upper Puna Ridge suggests a distinct body of magma cumulates, possibly connected to the summit magma cumulates at depth. The two cumulate bodies within Kilauea's ERZ may have undergone separate ductile flow seaward, influencing the submarine morphology of Kilauea's south flank. Low velocities (5.0-6.3??km/s) seaward of Kilauea's Hilina fault zone, and along Mauna Loa's seaward facing Kao'iki fault zone, are attributed to thick piles of volcaniclastic sediments deposited on the submarine flanks. Loihi seamount shows high-velocity anomalies beneath the summit and along the rift zones, similar to the interpreted magma cumulates below Mauna Loa and Kilauea volcanoes, and a low-velocity anomaly beneath the oceanic crust, probably indicative of melt within the upper mantle. Around Kilauea's submarine flank, a high-velocity anomaly beneath the outer bench suggests the presence of an ancient seamount that may obstruct outward spreading of the flank. Mauna Loa's southeast flank is also marked by a large, anomalously high-velocity feature (7.0-7.4??km/s), interpreted to define an inactive, buried volcanic rift zone, which might provide a new explanation for the westward migration of Mauna Loa's current SWRZ and the growth of Kilauea's SWRZ. ?? 2007 Elsevier B.V. All rights reserved.

  2. View-dependent streamlines for 3D vector fields.

    PubMed

    Marchesin, Stéphane; Chen, Cheng-Kai; Ho, Chris; Ma, Kwan-Liu

    2010-01-01

    This paper introduces a new streamline placement and selection algorithm for 3D vector fields. Instead of considering the problem as a simple feature search in data space, we base our work on the observation that most streamline fields generate a lot of self-occlusion which prevents proper visualization. In order to avoid this issue, we approach the problem in a view-dependent fashion and dynamically determine a set of streamlines which contributes to data understanding without cluttering the view. Since our technique couples flow characteristic criteria and view-dependent streamline selection we are able achieve the best of both worlds: relevant flow description and intelligible, uncluttered pictures. We detail an efficient GPU implementation of our algorithm, show comprehensive visual results on multiple datasets and compare our method with existing flow depiction techniques. Our results show that our technique greatly improves the readability of streamline visualizations on different datasets without requiring user intervention. PMID:20975200

  3. Loads and pressure evaluation of the flow around a flapping wing from instantaneous 3D velocity measurements

    NASA Astrophysics Data System (ADS)

    Tronchin, Thibaut; David, Laurent; Farcy, Alain

    2015-01-01

    The flow around a flapping wing is characterized by an unsteady evolution of three-dimensional vortices, which are one of the main sources of loads. The difficulty in directly measuring such low forces by means of sensors and the need of the characterization of the evolution of the flow have lead to the evaluation of loads using the integral form of the momentum equation. This paper describes methods for evaluating instantaneous loads and three-dimensional pressure fields using 3D3C velocity fields only. An evaluation of the accuracy of these methods using DNS velocity fields is presented. Loads and pressure fields are then calculated using scanning tomography PIV velocity fields, around a NACA 0012 airfoil for a flapping motion in a water tank at a Reynolds number of 1,000. The results suggest a sufficient accuracy of calculated pressure fields for a global analysis of the topology of the flow and for the evaluation of loads by integrating the calculated pressure field over the surface of the wing.

  4. Tuning the 3D plasmon field of nanohole arrays

    NASA Astrophysics Data System (ADS)

    Couture, Maxime; Liang, Yuzhang; Poirier Richard, Hugo-Pierre; Faid, Rita; Peng, Wei; Masson, Jean-Francois

    2013-11-01

    Modern photonics is being revolutionized through the use of nanostructured plasmonic materials, which confine light to sub-diffraction limit resolution providing universal, sensitive, and simple transducers for molecular sensors. Understanding the mechanisms by which light interacts with plasmonic crystals is essential for developing application-focussed devices. The strong influence of grating coupling on electromagnetic field distribution, frequency and degeneracy of plasmon bands has now been characterized using hexagonal nanohole arrays. An equation for nanohole arrays was derived to demonstrate the strong influence of incidence and rotation angle on optical properties of 2D plasmonic crystals such as nanohole arrays. Consequently, we report experimental data that are in strong agreement with finite difference time-domain (FDTD) simulations that clearly demonstrate the influence of the grating coupling conditions on the optical properties (such as plasmon degeneracy and bandwidth), and on the distribution of the plasmon field around nanohole arrays (including tuneable penetration depths and highly localized fields). The tuneable 3D plasmon field allowed for controlled sensing properties and by increasing the angle of incidence to 30 degrees, the resonance wavelength was tuned from 1000 to 600 nm, and the sensitivity was enhanced by nearly 300% for a protein assay using surface plasmon resonance (SPR) and by 40% with surface-enhanced Raman scattering (SERS) sensors.Modern photonics is being revolutionized through the use of nanostructured plasmonic materials, which confine light to sub-diffraction limit resolution providing universal, sensitive, and simple transducers for molecular sensors. Understanding the mechanisms by which light interacts with plasmonic crystals is essential for developing application-focussed devices. The strong influence of grating coupling on electromagnetic field distribution, frequency and degeneracy of plasmon bands has now been

  5. 3-D Velocity Model of the Coachella Valley, Southern California Based on Explosive Shots from the Salton Seismic Imaging Project

    NASA Astrophysics Data System (ADS)

    Persaud, P.; Stock, J. M.; Fuis, G. S.; Hole, J. A.; Goldman, M.; Scheirer, D. S.

    2014-12-01

    We have analyzed explosive shot data from the 2011 Salton Seismic Imaging Project (SSIP) across a 2-D seismic array and 5 profiles in the Coachella Valley to produce a 3-D P-wave velocity model that will be used in calculations of strong ground shaking. Accurate maps of seismicity and active faults rely both on detailed geological field mapping and a suitable velocity model to accurately locate earthquakes. Adjoint tomography of an older version of the SCEC 3-D velocity model shows that crustal heterogeneities strongly influence seismic wave propagation from moderate earthquakes (Tape et al., 2010). These authors improve the crustal model and subsequently simulate the details of ground motion at periods of 2 s and longer for hundreds of ray paths. Even with improvements such as the above, the current SCEC velocity model for the Salton Trough does not provide a match of the timing or waveforms of the horizontal S-wave motions, which Wei et al. (2013) interpret as caused by inaccuracies in the shallow velocity structure. They effectively demonstrate that the inclusion of shallow basin structure improves the fit in both travel times and waveforms. Our velocity model benefits from the inclusion of known location and times of a subset of 126 shots detonated over a 3-week period during the SSIP. This results in an improved velocity model particularly in the shallow crust. In addition, one of the main challenges in developing 3-D velocity models is an uneven stations-source distribution. To better overcome this challenge, we also include the first arrival times of the SSIP shots at the more widely spaced Southern California Seismic Network (SCSN) in our inversion, since the layout of the SSIP is complementary to the SCSN. References: Tape, C., et al., 2010, Seismic tomography of the Southern California crust based on spectral-element and adjoint methods: Geophysical Journal International, v. 180, no. 1, p. 433-462. Wei, S., et al., 2013, Complementary slip distributions

  6. A 3-D crustal velocity structure across the Variscides of southwest Ireland

    NASA Astrophysics Data System (ADS)

    Landes, M.; Readman, P. W.; O'Reilly, B. M.; Shannon, P. M.

    2003-04-01

    In the VARNET-96 experiment three seismic refraction profiles were acquired to examine the crustal structure in the south-west of Ireland. The shotpoint geometry allowed for both in-line and off-line fan shot recordings on the three profiles. Results of 3-D inversion modelling illustrate that there is pervasive lateral heterogeneity of the sedimentary and crustal velocity structure south of the Shannon Estuary. Palaeozoic strata at the south coast are about 5-6 km thick associated with the sedimentary infill of the Munster and South Munster Basins. To the north, shallow upper crust in the vicinity of the Killarney-Mallow Fault Zone is followed by a 3-4 km thick sedimentary succession in the Dingle-Shannon Basin. A zone of high-velocity upper crust (6.4-6.6 km/s) beneath the South Munster Basin correlates with a gravity high between the Kenmare-Killarney and the Leinster Granite gravity lows. Other high-velocity zones beneath Dingle Bay and the Kenmare River region may be associated with the deep traces of the Killarney-Mallow Fault Zone and the Cork-Kenmare Line. The 3-D velocity model was taken as a basis for the computation of PmP reflected arrivals from the crust-mantle boundary. The Moho depth varies from 28-29 km at the south coast to 32-33 km beneath the Dingle-Shannon Basin. Pervasive Variscan deformation appears to be confined to the sedimentary and upper crustal structure thus supporting a thin-skinned tectonic model for Variscan deformation. Deep-crustal variations only occur where they can be correlated with major tectonic features such as the Caledonian Iapetus Suture near the Shannon Estuary. The shallowing of the Moho towards the coast may result from Mesozoic crustal extension in the adjacent offshore sedimentary basins.

  7. Development of a Regional Velocity Model Using 3D Broadband Waveform Sensitivity

    NASA Astrophysics Data System (ADS)

    Panning, M. P.; Romanowicz, B. A.; Kim, A.

    2005-12-01

    We are developing a new approach which relies on a cascade of increasingly accurate theoretical approximations for computation of the seismic wavefield to develop a model of regional seismic velocity structure for eastern Eurasia using full seismic waveforms. The selected area is particularly suitable for the purpose of this experiment, as it is highly heterogeneous, presenting a challenge for standard modeling techniques, but it is well surrounded by earthquake sources and a significant number of high quality broadband digital stations exist, for which data are readily accessible through IRIS (Incorporated Research Institutions for Seismology) and the FDSN (Federation of Digital Seismic Networks). The initial model is derived from a large database of teleseismic long period waveforms (surface waves and overtone wavepackets) using well-developed theoretical approximations, the Path Average Approximation (PAVA) and Nonlinear Asymptotic Coupling Theory (NACT). These approaches assume waveforms are only sensitive to the 1D (PAVA) and 2D (NACT) structure in the vertical plane between source and receiver, which is adequate for the development of a smooth initial 3D velocity model. We refine this model using a more accurate theoretical approach. We utilize an implementation of a 3D Born approximation, which takes into account the contribution to the waveform from single scattering throughout the model, giving full 3D waveform sensitivity kernels. We perform verification tests of this approach for synthetic models, and show that it can accurately represent the wavefield as predicted by numerical approaches in several situations where approximations such as PAVA and NACT are insufficient. The Born 3D waveform sensitivity kernels are used to perform a higher resolution inversion of regional waveforms for a smaller subregion between longitudes 90 and 150 degrees E, and latitudes 15 and 40 degrees N. To further increase the accuracy of this model, we intend to utilize a very

  8. Exploration 3-D Seismic Field Test/Native Tribes Initiative

    SciTech Connect

    Carroll, Herbert B.; Chen, K.C.; Guo, Genliang; Johnson, W.I.; Reeves,T.K.; Sharma,Bijon

    1999-04-27

    To determine current acquisition procedures and costs and to further the goals of the President's Initiative for Native Tribes, a seismic-survey project is to be conducted on Osage tribal lands. The goals of the program are to demonstrate the capabilities, costs, and effectiveness of 3-D seismic work in a small-operator setting and to determine the economics of such a survey. For these purposes, typical small-scale independent-operator practices are being followed and a shallow target chose in an area with a high concentration of independent operators. The results will be analyzed in detail to determine if there are improvements and/or innovations which can be easily introduced in field-acquisition procedures, in processing, or in data manipulation and interpretation to further reduce operating costs and to make the system still more active to the small-scale operator.

  9. Spatial parallelism of a 3D finite difference, velocity-stress elastic wave propagation code

    SciTech Connect

    Minkoff, S.E.

    1999-12-01

    Finite difference methods for solving the wave equation more accurately capture the physics of waves propagating through the earth than asymptotic solution methods. Unfortunately, finite difference simulations for 3D elastic wave propagation are expensive. The authors model waves in a 3D isotropic elastic earth. The wave equation solution consists of three velocity components and six stresses. The partial derivatives are discretized using 2nd-order in time and 4th-order in space staggered finite difference operators. Staggered schemes allow one to obtain additional accuracy (via centered finite differences) without requiring additional storage. The serial code is most unique in its ability to model a number of different types of seismic sources. The parallel implementation uses the MPI library, thus allowing for portability between platforms. Spatial parallelism provides a highly efficient strategy for parallelizing finite difference simulations. In this implementation, one can decompose the global problem domain into one-, two-, and three-dimensional processor decompositions with 3D decompositions generally producing the best parallel speedup. Because I/O is handled largely outside of the time-step loop (the most expensive part of the simulation) the authors have opted for straight-forward broadcast and reduce operations to handle I/O. The majority of the communication in the code consists of passing subdomain face information to neighboring processors for use as ghost cells. When this communication is balanced against computation by allocating subdomains of reasonable size, they observe excellent scaled speedup. Allocating subdomains of size 25 x 25 x 25 on each node, they achieve efficiencies of 94% on 128 processors. Numerical examples for both a layered earth model and a homogeneous medium with a high-velocity blocky inclusion illustrate the accuracy of the parallel code.

  10. Spatial Parallelism of a 3D Finite Difference, Velocity-Stress Elastic Wave Propagation Code

    SciTech Connect

    MINKOFF,SUSAN E.

    1999-12-09

    Finite difference methods for solving the wave equation more accurately capture the physics of waves propagating through the earth than asymptotic solution methods. Unfortunately. finite difference simulations for 3D elastic wave propagation are expensive. We model waves in a 3D isotropic elastic earth. The wave equation solution consists of three velocity components and six stresses. The partial derivatives are discretized using 2nd-order in time and 4th-order in space staggered finite difference operators. Staggered schemes allow one to obtain additional accuracy (via centered finite differences) without requiring additional storage. The serial code is most unique in its ability to model a number of different types of seismic sources. The parallel implementation uses the MP1 library, thus allowing for portability between platforms. Spatial parallelism provides a highly efficient strategy for parallelizing finite difference simulations. In this implementation, one can decompose the global problem domain into one-, two-, and three-dimensional processor decompositions with 3D decompositions generally producing the best parallel speed up. Because i/o is handled largely outside of the time-step loop (the most expensive part of the simulation) we have opted for straight-forward broadcast and reduce operations to handle i/o. The majority of the communication in the code consists of passing subdomain face information to neighboring processors for use as ''ghost cells''. When this communication is balanced against computation by allocating subdomains of reasonable size, we observe excellent scaled speed up. Allocating subdomains of size 25 x 25 x 25 on each node, we achieve efficiencies of 94% on 128 processors. Numerical examples for both a layered earth model and a homogeneous medium with a high-velocity blocky inclusion illustrate the accuracy of the parallel code.

  11. 3D Droplet velocities and sizes in the Ranque-Hilsch vortex tube

    NASA Astrophysics Data System (ADS)

    Liew, R.; Zeegers, J. C. H.; Kuerten, J. G. M.; Michalek, W. R.

    2012-11-01

    The Ranque-Hilsch vortex tube is a known device that is used to generate spot cooling. In this study, we experimentally investigate the behavior of small water droplets in the vortex tube by means of Phase Doppler Particle Analysis. In an experimental vortex tube, droplets were injected together with a carrier gas to form a fast rotating (up to 80.000 rpm) droplet-gas mixture. Droplet sizes, 3D velocity components, and turbulent properties were measured, showing high intensity isotropic turbulence in the core region. To investigate the cause of the high intensity turbulence, a frequency analysis was applied on the measured velocity. The frequency spectrum of the velocity is presented and indicates that wobbling of the vortex axis is the cause of the high turbulence intensity. It was expected that larger droplets have a higher radial velocity because of the larger centrifugal force. Results show, however, that small and lager droplets behave similar. This research is supported by the Dutch Technology Foundation STW, which is the applied science division of NWO, and the Technology Programme of the Ministry of Economic Affairs.

  12. Advanced prior modeling for 3D bright field electron tomography

    NASA Astrophysics Data System (ADS)

    Sreehari, Suhas; Venkatakrishnan, S. V.; Drummy, Lawrence F.; Simmons, Jeffrey P.; Bouman, Charles A.

    2015-03-01

    Many important imaging problems in material science involve reconstruction of images containing repetitive non-local structures. Model-based iterative reconstruction (MBIR) could in principle exploit such redundancies through the selection of a log prior probability term. However, in practice, determining such a log prior term that accounts for the similarity between distant structures in the image is quite challenging. Much progress has been made in the development of denoising algorithms like non-local means and BM3D, and these are known to successfully capture non-local redundancies in images. But the fact that these denoising operations are not explicitly formulated as cost functions makes it unclear as to how to incorporate them in the MBIR framework. In this paper, we formulate a solution to bright field electron tomography by augmenting the existing bright field MBIR method to incorporate any non-local denoising operator as a prior model. We accomplish this using a framework we call plug-and-play priors that decouples the log likelihood and the log prior probability terms in the MBIR cost function. We specifically use 3D non-local means (NLM) as the prior model in the plug-and-play framework, and showcase high quality tomographic reconstructions of a simulated aluminum spheres dataset, and two real datasets of aluminum spheres and ferritin structures. We observe that streak and smear artifacts are visibly suppressed, and that edges are preserved. Also, we report lower RMSE values compared to the conventional MBIR reconstruction using qGGMRF as the prior model.

  13. Pipe3D, a pipeline to analyze Integral Field Spectroscopy Data: I. New fitting philosophy of FIT3D

    NASA Astrophysics Data System (ADS)

    Sánchez, S. F.; Pérez, E.; Sánchez-Blázquez, P.; González, J. J.; Rosález-Ortega, F. F.; Cano-Dí az, M.; López-Cobá, C.; Marino, R. A.; Gil de Paz, A.; Mollá, M.; López-Sánchez, A. R.; Ascasibar, Y.; Barrera-Ballesteros, J.

    2016-04-01

    We present an improved version of FIT3D, a fitting tool for the analysis of the spectroscopic properties of the stellar populations and the ionized gas derived from moderate resolution spectra of galaxies. This tool was developed to analyze integral field spectroscopy data and it is the basis of Pipe3D, a pipeline used in the analysis of CALIFA, MaNGA, and SAMI data. We describe the philosophy and each step of the fitting procedure. We present an extensive set of simulations in order to estimate the precision and accuracy of the derived parameters for the stellar populations and the ionized gas. We report on the results of those simulations. Finally, we compare the results of the analysis using FIT3D with those provided by other widely used packages, and we find that the parameters derived by FIT3D are fully compatible with those derived using these other tools.

  14. 3-D crustal velocity model for Lithuania and its application to local event studies

    NASA Astrophysics Data System (ADS)

    Kozlovskaya, Elena; Budraitis, Mantas; Janutyte, Ilma; Motuza, Gediminas; Lazauskiene, Jurga; Passeq-Working Group

    2010-05-01

    PASSEQ 2006-2008 project (PASsive Seismic Experiment in TESZ) aimed at studying the lithosphere-asthenosphere system around the TransEuropean Suture Zone (TESZ)- the transition between old Proterozoic platform of north and east Europe and younger Phanerozoic platform in central and western Europe. The experiment was a seismic array research aiming to retrieve the structure of the crust and Earth's mantle down to the mantle transition zone, including mapping of upper mantle seismic velocity variations and discontinuities (Moho, lithosphere-asthenosphere boundary, mantle transition zone) using all available techniques. During the experiment 26 seismic stations (including four broadband stations) were installed in Lithuania. One of the main targets of PASSEQ deployment in Lithuania was identification and characterization of the local seismic activity. The PASSEQ stations in Lithuania were in operation since June, 2006 till January, 2008. During this period a number of local seismic events was recorded and preliminary event location was made using the LocSat algorithm and 1-D velocity model. This standard procedure is not enough precise for Lithuania, however, because the thickness of the crust varies significantly in the region (from 45 to 55 km). In order to improve event location, we separated the events into several groups and located each group separately using a VELEST algorithms and own 1-D velocity model for each group. We also compiled a 3-D seismic velocity of the crust down to a depth of 60 km. The model, consisting of four major layers (sediments, upper crust, middle crust, lower crust and uppermost mantle) was interpolated from 2-D velocity models along previous wide-angle reflection and refraction profiles into a regular grid. The quality of the approximation was analysed using comparison of travel times of P-waves recorded along previous controlled source profiles and synthetic travel times calculated using the 3-D velocity model. The model was converted

  15. Imaging of 3-D seismic velocity structure of Southern Sumatra region using double difference tomographic method

    SciTech Connect

    Lestari, Titik; Nugraha, Andri Dian

    2015-04-24

    Southern Sumatra region has a high level of seismicity due to the influence of the subduction system, Sumatra fault, Mentawai fault and stretching zone activities. The seismic activities of Southern Sumatra region are recorded by Meteorological Climatological and Geophysical Agency (MCGA’s) Seismograph network. In this study, we used earthquake data catalog compiled by MCGA for 3013 events from 10 seismic stations around Southern Sumatra region for time periods of April 2009 – April 2014 in order to invert for the 3-D seismic velocities structure (Vp, Vs, and Vp/Vs ratio). We applied double-difference seismic tomography method (tomoDD) to determine Vp, Vs and Vp/Vs ratio with hypocenter adjustment. For the inversion procedure, we started from the initial 1-D seismic velocity model of AK135 and constant Vp/Vs of 1.73. The synthetic travel time from source to receiver was calculated using ray pseudo-bending technique, while the main tomographic inversion was applied using LSQR method. The resolution model was evaluated using checkerboard test and Derivative Weigh Sum (DWS). Our preliminary results show low Vp and Vs anomalies region along Bukit Barisan which is may be associated with weak zone of Sumatran fault and migration of partial melted material. Low velocity anomalies at 30-50 km depth in the fore arc region may indicated the hydrous material circulation because the slab dehydration. We detected low seismic seismicity in the fore arc region that may be indicated as seismic gap. It is coincides contact zone of high and low velocity anomalies. And two large earthquakes (Jambi and Mentawai) also occurred at the contact of contrast velocity.

  16. Imaging of 3-D seismic velocity structure of Southern Sumatra region using double difference tomographic method

    NASA Astrophysics Data System (ADS)

    Lestari, Titik; Nugraha, Andri Dian

    2015-04-01

    Southern Sumatra region has a high level of seismicity due to the influence of the subduction system, Sumatra fault, Mentawai fault and stretching zone activities. The seismic activities of Southern Sumatra region are recorded by Meteorological Climatological and Geophysical Agency (MCGA's) Seismograph network. In this study, we used earthquake data catalog compiled by MCGA for 3013 events from 10 seismic stations around Southern Sumatra region for time periods of April 2009 - April 2014 in order to invert for the 3-D seismic velocities structure (Vp, Vs, and Vp/Vs ratio). We applied double-difference seismic tomography method (tomoDD) to determine Vp, Vs and Vp/Vs ratio with hypocenter adjustment. For the inversion procedure, we started from the initial 1-D seismic velocity model of AK135 and constant Vp/Vs of 1.73. The synthetic travel time from source to receiver was calculated using ray pseudo-bending technique, while the main tomographic inversion was applied using LSQR method. The resolution model was evaluated using checkerboard test and Derivative Weigh Sum (DWS). Our preliminary results show low Vp and Vs anomalies region along Bukit Barisan which is may be associated with weak zone of Sumatran fault and migration of partial melted material. Low velocity anomalies at 30-50 km depth in the fore arc region may indicated the hydrous material circulation because the slab dehydration. We detected low seismic seismicity in the fore arc region that may be indicated as seismic gap. It is coincides contact zone of high and low velocity anomalies. And two large earthquakes (Jambi and Mentawai) also occurred at the contact of contrast velocity.

  17. 3D crack tip fields for FCC single crystals

    SciTech Connect

    Cuitino, A.M.; Ortiz, M.

    1995-12-31

    Cracks in single crystals are of concern in a number of structural and non-structural applications, ranging form single-crystal turbine blades and rotors to metal interconnect lines in microcircuits. In this paper we present 3D numerical simulations of the crack-tip fields of a Cu single crystal, including stress, strain and slip activity patterns. The orientation of the crack tip is along the crystallographic orientation (101), while the crack plane is (010). A material model based on dislocation mechanics is used in these simulations. This model correctly predicts the observed behavior of Cu, including the basic hardening characteristics of single crystals, orientation dependence and stage I-II-III structure of the stress-strain curves, the observed levels of latent hardening and their variation with orientation and deformation in the primary system and slip activities and dislocation densities. We use the FEM within the context of finite deformation plasticity. In the figure below, we show the finite element mesh composed by 12-noded tetrahedrons with 6-noded triangular faces. The model simulates half of a beam, which is subjected to a concentrated load at 1/8 of total length from the support. Detailed results of the stress, deformation and slip activity are presented at different radii from crack tip and at different depths from the surface. In general, the results show a strong difference in the slip activity pattern form the interior to the exterior, while smaller differences are encountered in the stress and strain fields.

  18. 3-D Finite Element Analyses of the Egan Cavern Field

    SciTech Connect

    Klamerus, E.W.; Ehgartner, B.L.

    1999-02-01

    Three-dimensional finite element analyses were performed for the two gas-filled storage caverns at the Egan field, Jennings dome, Louisiana. The effects of cavern enlargement on surface subsidence, storage loss, and cavern stability were investigated. The finite element model simulated the leaching of caverns to 6 and 8 billion cubic feet (BCF) and examined their performance at various operating conditions. Operating pressures varied from 0.15 psi/ft to 0.9 psi/ft at the bottom of the lowest cemented casing. The analysis also examined the stability of the web or pillar of salt between the caverns under differential pressure loadings. The 50-year simulations were performed using JAC3D, a three dimensional finite element analysis code for nonlinear quasistatic solids. A damage criterion based on onset of dilatancy was used to evaluate cavern instability. Dilation results from the development of microfractures in salt and, hence, potential increases in permeability onset occurs well before large scale failure. The analyses predicted stable caverns throughout the 50-year period for the range of pressures investigated. Some localized salt damage was predicted near the bottom walls of the caverns if the caverns are operated at minimum pressure for long periods of time. Volumetric cavern closures over time due to creep were moderate to excessive depending on the salt creep properties and operating pressures. However, subsidence above the cavern field was small and should pose no problem, to surface facilities.

  19. New techniques in 3D scalar and vector field visualization

    SciTech Connect

    Max, N.; Crawfis, R.; Becker, B.

    1993-05-05

    At Lawrence Livermore National Laboratory (LLNL) we have recently developed several techniques for volume visualization of scalar and vector fields, all of which use back-to-front compositing. The first renders volume density clouds by compositing polyhedral volume cells or their faces. The second is a ``splatting`` scheme which composites textures used to reconstruct the scalar or vector fields. One version calculates the necessary texture values in software, and another takes advantage of hardware texture mapping. The next technique renders contour surface polygons using semi-transparent textures, which adjust appropriately when the surfaces deform in a flow, or change topology. The final one renders the ``flow volume`` of smoke or dye tracer swept out by a fluid flowing through a small generating polygon. All of these techniques are applied to a climate model data set, to visualize cloud density and wind velocity.

  20. The 3D Space and Spin Velocities of a Gamma-ray Pulsar

    NASA Astrophysics Data System (ADS)

    Romani, Roger W.

    2016-04-01

    PSR J2030+4415 is a LAT-discovered 0.5My-old gamma-ray pulsar with an X-ray synchrotron trail and a rare Halpha bowshock. We have obtained GMOS IFU spectroscopic imaging of this shell, and show a sweep through the remarkable Halpha structure, comparing with the high energy emission. These data provide a unique 3D map of the momentum distribution of the relativistic pulsar wind. This shows that the pulsar is moving nearly in the plane of the sky and that the pulsar wind has a polar component misaligned with the space velocity. The spin axis is shown to be inclined some 95degrees to the Earth line of sight, explaining why this is a radio-quiet, gamma-only pulsar. Intriguingly, the shell also shows multiple bubbles that suggest that the pulsar wind power has varied substantially over the past 500 years.

  1. Velocity and Density Models Incorporating the Cascadia Subduction Zone for 3D Earthquake Ground Motion Simulations

    USGS Publications Warehouse

    Stephenson, William J.

    2007-01-01

    INTRODUCTION In support of earthquake hazards and ground motion studies in the Pacific Northwest, three-dimensional P- and S-wave velocity (3D Vp and Vs) and density (3D rho) models incorporating the Cascadia subduction zone have been developed for the region encompassed from about 40.2?N to 50?N latitude, and from about -122?W to -129?W longitude. The model volume includes elevations from 0 km to 60 km (elevation is opposite of depth in model coordinates). Stephenson and Frankel (2003) presented preliminary ground motion simulations valid up to 0.1 Hz using an earlier version of these models. The version of the model volume described here includes more structural and geophysical detail, particularly in the Puget Lowland as required for scenario earthquake simulations in the development of the Seattle Urban Hazards Maps (Frankel and others, 2007). Olsen and others (in press) used the model volume discussed here to perform a Cascadia simulation up to 0.5 Hz using a Sumatra-Andaman Islands rupture history. As research from the EarthScope Program (http://www.earthscope.org) is published, a wealth of important detail can be added to these model volumes, particularly to depths of the upper-mantle. However, at the time of development for this model version, no EarthScope-specific results were incorporated. This report is intended to be a reference for colleagues and associates who have used or are planning to use this preliminary model in their research. To this end, it is intended that these models will be considered a beginning template for a community velocity model of the Cascadia region as more data and results become available.

  2. 3D P and S Wave Velocity Structure and Tremor Locations in the Parkfield Region

    NASA Astrophysics Data System (ADS)

    Zeng, X.; Thurber, C. H.; Shelly, D. R.; Bennington, N. L.; Cochran, E. S.; Harrington, R. M.

    2014-12-01

    We have assembled a new dataset to refine the 3D seismic velocity model in the Parkfield region. The S arrivals from 184 earthquakes recorded by the Parkfield Experiment to Record MIcroseismicity and Tremor array (PERMIT) during 2010-2011 were picked by a new S wave picker, which is based on machine learning. 74 blasts have been assigned to four quarries, whose locations were identified with Google Earth. About 1000 P and S wave arrivals from these blasts at permanent seismic network were also incorporated. Low frequency earthquakes (LFEs) occurring within non-volcanic tremor (NVT) are valuable for improving the precision of NVT location and the seismic velocity model at greater depths. Based on previous work (Shelley and Hardebeck, 2010), waveforms of hundreds of LFEs in same family were stacked to improve signal qualify. In a previous study (McClement et al., 2013), stacked traces of more than 30 LFE families at the Parkfileld Array Seismic Observatory (PASO) have been picked. We expanded our work to include LFEs recorded by the PERMIT array. The time-frequency Phase Weight Stacking (tf-PWS) method was introduced to improve the stack quality, as direct stacking does not produce clear S-wave arrivals on the PERMIT stations. This technique uses the coherence of the instantaneous phase among the stacked signals to enhance the signal-to-noise ratio (SNR) of the stack. We found that it is extremely effective for picking LFE arrivals (Thurber et al., 2014). More than 500 P and about 1000 S arrivals from 58 LFE families were picked at the PERMIT and PASO arrays. Since the depths of LFEs are much deeper than earthquakes, we are able to extend model resolution to lower crustal depths. Both P and S wave velocity structure have been obtained with the tomoDD method. The result suggests that there is a low velocity zone (LVZ) in the lower crust and the location of the LVZ is consistent with the high conductivity zone beneath the southern segment of the Rinconada fault that

  3. Near-wall 3D velocity measurements above biomimetic shark skin denticles using Digital In-line Holographic Microscopy

    NASA Astrophysics Data System (ADS)

    Toloui, Mostafa; Brajkovic, David; Hong, Jiarong

    2014-11-01

    Digital In-line Holography is employed to image 3D flow structures in the vicinity of a transparent rough surface consisting of closely packed biomimetic shark skin denticles as roughness elements. The 3D printed surface replicates the morphological features of real shark skin, and the denticles have a geometrical scale of 2 mm, i.e. 10 times of the real ones. In order to minimize optical aberrations near the fluid-roughness interface and enable flow measurements around denticles, the optical refractive index of the fluid medium is maintained the same as that of the denticle model in an index-matched flow facility using NaI solution as the working fluid. The experiment is conducted in a 1.2 m long test section with 50 mm × 50 mm cross section. The sampling volume is located in the downstream region of a shark skin replica of 12'' stretch where the turbulent flow is fully-developed and the transitional effect from smooth to the rough surface becomes negligible. Several instantaneous realizations of the 3D velocity field are obtained and are used to illustrate turbulent coherent structures induced by shark-skin denticles. This information will provide insights on the hydrodynamic function of shark's unique surface ornamentation.

  4. The crustal and mantle velocity structure in central Asia from 3D traveltime tomography

    NASA Astrophysics Data System (ADS)

    Sun, Y.; Martin, R. V.; Toksoz, M. N.; Pei, S.

    2010-12-01

    The lithospheric structure in central Asia features large blocks such as the Indian plate, the Afghan block, the Turan plate, and the Tarim block. This geologically and tectonically complicated area is also one of the most seismically active regions in the world. We developed P- and S- wave velocity structures of the central Asia in the crust using the traveltime data from Kyrgyzstan, Tajikistan, Kazakhstan, and Uzbek. We chose the events and stations between 32N65E and 45N85E and focused on the areas of Pamir and western Tianshan. In this data set, there are more than 6000 P and S arrivals received at 80 stations from about 300 events. The double difference tomography is applied to relocate events and to invert for seismic structures simultaneously. Our results provide accurate locations of earthquakes and high resolution crustal structure in this region. To extend the model deeper into the mantle through the upper mantle transition zone, ISC/EHB data for P and PP phases are combined with the ABCE data. To counteract the “smearing effect,” the crust and upper mantle velocity structure, derived from regional travel-times, is used. An adaptive grid method based on ray density is used in the inversion. A P-wave velocity model extending down to a depth of 2000 km is obtained. regional-teleseismic tomography provides a high-resolution, 3-D P-wave velocity model for the crust, upper mantle, and the transition zone. The crustal models correlate well with geologic and tectonic features. The upper mantle tomograms show the images of Tian Shan. The slab geometry is quite complex, reflecting the history of the changes in the plate motions and collision processes. Vp/Vs tomography was also determined in the study region, and an attenuation tomography was obtained as well.

  5. 3-D Crustal Velocity Structure Across the Vrancea Zone in Romania, Derived From Seismic Data

    NASA Astrophysics Data System (ADS)

    Landes, M.; Hauser, F.; Popa, M.

    2002-12-01

    The Vrancea zone in the south-eastern Carpathians is one of the most active seismic zones in Europe. In order to study the crustal and upper-mantle structure in this region, two seismic refraction/wide-angle reflection experiments were carried out in 1999 and 2001. The 1999 campaign comprised a 320 km long N-S profile and a 80 km long transverse profile (E-W). All shots were recorded simultaneously on both profiles. The profile conducted in 2001 extended in E-W direction from the Hungarian border across the Vrancea zone to the Black Sea. We present an application of a 3-D refraction and reflection tomography algorithm (Hole 1992, 1995), elaborating the crustal velocity and interface structure within a 115 x 235 km wide region around the Vrancea zone. In order to enhance the model resolution, first arrival data from local earthquakes of the CALIXTO-99 teleseismic project were also included. The results indicate a high-velocity structure beneath the northern part of the Vrancea zone extending from shallow levels to depths of about 11 km. This structure may be related to the Trotus and Capidava-Ovidiu faults, which converge to the north of it. The high-velocity region is surrounded by the lower velocity Focsani and Brasov basins. The sedimentary succession beneath the southern part of the model extends to 18 km depth, while in the north sediment thickness varies between 10 and 15 km. Further results of the interface modelling of prominent reflections show that the mid-crustal and Moho interfaces shallow northwards from 30 km to 22 km and from 42 km to 38 km, respectively. This correlates well with previous results of Hauser et al. (2001).

  6. 3-D Isotropic and Anisotropic S-velocity Structure in the North American Upper Mantle

    NASA Astrophysics Data System (ADS)

    Yuan, H.; Marone, F.; Romanowicz, B.; Abt, D.; Fischer, K.

    2008-12-01

    The tectonic diversity of the North American continent has led to a number of geological, tectonic and geodynamical models, many of which can be better tested with high resolution 3-d tomographic models of the isotropic and anisotropic mantle structure of the continent. In the framework of non-linear asymptotic coupling theory (NACT), we recently developed tools to invert long period seismic waveforms combined with SKS splitting data, for both isotropic and radial and azimuthal anisotropic S-wave velocity structure in the upper mantle at the continental scale (Marone et al., 2007; Marone and Romanowicz, 2007). Striking differences in both isotropic and anisotropic velocity structure were observed: beneath the high velocity stable cratonic region a distinct two-layer anisotropic domain is present, with the bottom layer fast axis direction aligned with the absolute plate motion, and a shallower lithospheric layer with north pointing fast axis most likely showing records of past tectonic history; under the active western US the direction of tomographically inferred anisotropy is stable with depth and compatible with the absolute plate motion direction. Here we present an updated model which includes nearly five more years of data, including data from newly operative USArray stations, and a somewhat more extended frequency band. Our new model confirms our previous results, and reveals greater yet complex details of the anisotropic velocity structure beneath the western U.S.. We also show initial results of incorporating constraints on the depth to the lithosphere-asthenosphere boundary (LAB) using teleseismic receiver functions. We discuss the different anisotropic domains resolved both laterally and in depth, in the context of tectonic history of the north American continent.

  7. RV functional imaging: 3-D echo-derived dynamic geometry and flow field simulations.

    PubMed

    Pasipoularides, Ares D; Shu, Ming; Womack, Michael S; Shah, Ashish; Von Ramm, Olaf; Glower, Donald D

    2003-01-01

    We describe a novel functional imaging approach for quantitative analysis of right ventricular (RV) blood flow patterns in specific experimental animals (or humans) using real-time, three-dimensional (3-D) echocardiography (RT3D). The method is independent of the digital imaging modality used. It comprises three parts. First, a semiautomated segmentation aided by intraluminal contrast medium locates the RV endocardial surface. Second, a geometric scheme for dynamic RV chamber reconstruction applies a time interpolation procedure to the RT3D data to quantify wall geometry and motion at 400 Hz. A volumetric prism method validated the dynamic geometric reconstruction against simultaneous sonomicrometric canine measurements. Finally, the RV endocardial border motion information is used for mesh generation on a computational fluid dynamics solver to simulate development of the early RV diastolic inflow field. Boundary conditions (tessellated endocardial surface nodal velocities) for the solver are directly derived from the endocardial geometry and motion information. The new functional imaging approach may yield important kinematic information on the distribution of instantaneous velocities in the RV diastolic flow field of specific normal or diseased hearts. PMID:12388220

  8. Imaging 3D anisotropic upper mantle shear velocity structure of Southeast Asia using seismic waveform inversion

    NASA Astrophysics Data System (ADS)

    Chong, J.; Yuan, H.; French, S. W.; Romanowicz, B. A.; Ni, S.

    2011-12-01

    Southeast Asia as a special region in the world which is seismically active and is surrounded by active tectonic belts, such as the Himalaya collision zone, western Pacific subduction zones and the Tianshan- Baikal tectonic belt. Seismic anisotropic tomography can shade light on the complex crust and upper mantle dynamics of this region, which is the subject of much debate. In this study, we applied full waveform time domain tomography to image 3D isotropic and anisotropic upper mantle shear velocity structure of Southeast Asia. Three component waveforms of teleseismic and far regional events (15 degree ≤ Δ≤ 165 degree) with magnitude ranges from Mw6.0 to Mw7.0 are collected from 91 permanent and 438 temporary broadband seismic stations in SE Asia. Wavepackets of both fundamental and overtone modes, filtered between 60 and 400 sec, are selected automatically according to the similarity between data and synthetic waveforms (Panning & Romanowicz, 2006). Wavepackets corresponding to event-station paths that sample the region considered are weighted according to path redundancy and signal to noise ratio. Higher modes and fundamental mode wavepackets are weighted separately in order to enhance the contribution of higher modes which are more sensitive to deeper structure compared to the fundamental mode. Synthetic waveforms and broadband sensitivity kernels are computed using normal mode asymptotic coupling theory (NACT, Li & Romanowicz, 1995). As a starting model, we consider a global anisotropic upper mantle shear velocity model based on waveform inversion using the Spectral Element Method (Lekic & Romanowicz, 2011), updated for more realistic crustal thickness (French et al., 2011) as our starting model, we correct waveforms for the effects of 3D structure outside of the region, and invert them for perturbations in the 3D structure of the target region only. We start with waveform inversion down to 60sec and after several iterations, we include shorter period

  9. Coronal Outflow Velocities in a 3D Coronal Model Determined from UVCS Doppler Dimming Observations

    NASA Astrophysics Data System (ADS)

    Strachan, L.; Panasyuk, A. V.; Dobrzycka, D.; Gibson, S.; Biesecker, D. A.; Ko, Y.-K.; Galvin, A. B.; Romoli, M.; Kohn, J. L.

    1998-04-01

    We constrain coronal outflow velocity solutions, resolved along the line-of-sight, by using Doppler dimming models of H I Lyman alpha and O VI 1032/1037 Angstrom emissivities obtained with data from the Ultraviolet Coronagraph Spectrometer (UVCS) on SOHO. The local emissivities, from heliocentric heights of 1.5 to 3.0 radii, were determined from 3-D reconstructions of line-of-sight intensities obtained during the Whole Sun Month Campaign (10 Aug. -- 8 Sep. 1996). The models use electron densities derived from polarized brightness measurements made with the visible light coronagraphs on UVCS and LASCO, supplemented with data from Mark III at NCAR/MLSO. Electron temperature profiles are derived from `freezing-in' temperatures obtained from an analysis of charge state data from SWICS/Ulysses. The work concentrates on O5+ outflow velocities which are determined from an analysis of the the O VI line ratios. This analysis is less sensitive to the uncertainties in the electron density and independent of the ionization balance and elemental abundance than the analyses which use individual spectral lines. This work is supported in part by NASA under grant NAG-3192 to the Smithsonian Astrophysical Observatory, by the Italian Space Agency and by Swiss funding agencies.

  10. Validating 3D Seismic Velocity Models Using the Spectral Element Method

    NASA Astrophysics Data System (ADS)

    Maceira, M.; Rowe, C. A.; Allen, R. M.; Obrebski, M. J.

    2010-12-01

    As seismic instrumentation, data storage and dissemination and computational power improve, seismic velocity models attempt to resolve smaller structures and cover larger areas. However, it is unclear how accurate these velocity models are and, while the best models available are used for event determination, it is difficult to put uncertainties on seismic event parameters. Model validation is typically done using resolution tests that assume the imaging theory used is accurate and thus only considers the impact of the data coverage on resolution. We present the results of a more rigorous approach to model validation via full three-dimensional waveform propagation using Spectral Element Methods (SEM). This approach makes no assumptions about the theory used to generate the models but require substantial computational resources. We first validate 3D tomographic models for the Western USA generated using both ray-theoretical and finite-frequency methods. The Dynamic North America (DNA) Models of P- and S- velocity structure (DNA09-P and DNA09-S) use teleseismic body-wave traveltime residuals recorded at over 800 seismic stations provided by the Earthscope USArray and regional seismic networks. We performed systematic computations of synthetics for the dataset used to generate the DNA models. Direct comparison of these synthetic seismograms to the actual observations allows us to accurately assess and validate the models. Implementation of the method for a densely instrumented region such as that covered by the DNA model provides a useful testbed for the validation methods that we will subsequently apply to other, more challenging study areas.

  11. Poloidal structure of the plasma edge with 3D magnetic fields

    NASA Astrophysics Data System (ADS)

    Agostini, Matteo; Scarin, Paolo; Carraro, Lorella; Spizzo, Gianluca; Spolaore, Monica; Vianello, Nicola

    2015-11-01

    In the RFX-mod reversed-field pinch, when the magnetic field spontaneously develops a non axi-symmetric structure, also the plasma edge assumes a three dimensional shape. In previous RFX works, it has been shown that kinetic properties of the plasma (electron pressure, connection lengths, floating potential, influx, plasma flow) closely follow the symmetry of the 3D field, both in amplitude and phase, along the toroidal angle (i.e, the RFP perpendicular direction in the edge). Using a set of poloidally distributed diagnostics, it is shown that these same properties follow the poloidal periodicity (m =1) of the field. However, the behavior of the phase is more difficult to understand. In particular, the 3D modulation of the plasma potential can rotate in the poloidal direction with the typical velocity of 100m/s, similar in value with the phase velocity of the m =1 magnetic mode; or it can jump between inboard and outboard equatorial midplane. Moreover, when the floating potential structure rotates, there are preliminary indications that its direction depends on the plasma density: it follows the m =1 mode at higher density, and rotates in the opposite direction at lower density.

  12. SALSA3D: Validating a Global 3D P-Velocity Model of the Earth's Crust and Mantle for Improved Event Location

    NASA Astrophysics Data System (ADS)

    Begnaud, M. L.; Ballard, S.; Young, C. J.; Hipp, J. R.; Encarnacao, A.; Phillips, W. S.; Chael, E. P.; Rowe, C. A.

    2012-12-01

    We are developing a global 3D P wave velocity model of the Earth's crust and mantle using seismic tomography to assess improvement to seismic event locations obtained using high quality 3D Earth models in lieu of 1D and 2/2.5D models. We present the most recent version of SALSA3D (SAndia LoS Alamos 3D) version 1.9, and demonstrate its ability to reduce mislocations for a large set of realizations derived from a carefully chosen set of globally-distributed ground truth (GT) events. Our model is derived from the latest version of the GT catalog of P/Pn travel-time picks assembled by Los Alamos National Laboratory. For this current version, we employ more robust data quality control measures than previously used, as well as additional global GT data sources. To prevent over-weighting due to ray path redundancy and to reduce the computational burden, we cluster rays into representative rays. The model is represented using the triangular tessellation system described by Ballard et al. (2009), which incorporates variable resolution in both the geographic and radial dimensions. For our starting model, we use a simplified layer crustal model derived from the NNSA Unified model in Eurasia and Crust 2.0 model everywhere else, overlying a uniform ak135 mantle. Sufficient damping is used to reduce velocity adjustments so that ray path changes between iterations are small. We obtain proper model smoothness by using progressive grid refinement, refining the grid only in areas where the data warrant such a refinement. In previous versions, we based this refinement on velocity changes from previous model iterations. For the current version, we utilize the diagonal of the model resolution matrix to control where grid refinement occurs, resulting in more consistent and continuous areas of refinement than before. In addition to the changes in grid refinement, we also employ a more robust convergence criterion between successive grid refinements, allowing a better fit to first broader

  13. Measurement of surface velocity fields

    NASA Technical Reports Server (NTRS)

    Mann, J. A., Jr.

    1979-01-01

    A new technique for measuring surface velocity fields is briefly described. It determines the surface velocity vector as a function of location and time by the analysis of thermal fluctuations of the surface profile in a small domain around the point of interest. The apparatus now being constructed will be used in a series of experiments involving flow fields established by temperature gradients imposed along a surface.

  14. 3D Seismic Velocity Structure Around Philippine Sea Slab Subducting Beneath Kii Peninsula, Japan

    NASA Astrophysics Data System (ADS)

    Shibutani, T.; Imai, M.; Hirahara, K.; Nakao, S.

    2013-12-01

    Kii Peninsula is a part of the source area of Nankai Trough megaquakes and the region through which the strong seismic waves propagate to big cities in Kansai such as Osaka, Kyoto, Nara, Kobe, and so on. Moreover, the rupture starting point is thought to be possibly at off the peninsula. Therefore, it is important for simulations of the megaquakes and the strong motions to estimate accurately the configuration of the Philippine Sea slab and the seismic velocity structure around the slab and to investigate properties and conditions of the plate boundary surface. Deep low frequency events (DLFEs) are widely distributed from western Shikoku to central Tokai at 30 - 40 km depths on the plate boundary (Obara, 2002). Results from seismic tomography and receiver function analyses revealed that the oceanic crust of the Philippine Sea plate had a low velocity and a high Vp/Vs ratio (Hirose et al., 2007; Ueno et al., 2008). Hot springs with high 3He/4He ratios are found in an area between central Kinki and Kii Peninsula despite in the forearc region (Sano and Wakita, 1985). These phenomena suggest the process that H2O subducting with the oceanic crust dehydrates at the depths, causes the DLFEs, and moves to shallower depths. We carried out linear array seismic observations in the Kii Peninsula since 2004 in order to estimate the structure of the Philippine Sea slab and the surrounding area. We have performed receiver function analyses for four profile lines in the dipping direction of the slab and two lines in the perpendicular direction so far. We estimated three dimensional shapes of seismic velocity discontinuities such as the continental Moho, the upper surface of the oceanic crust and the oceanic Moho (Imai et al., 2013, this session). In addition, we performed seismic tomography with a velocity model embedded the discontinuities and observed travel times at stations in the linear arrays, and successfully estimated 3D seismic velocity structure around the Philippine Sea

  15. SALSA3D - Improving Event Locations Using a Global 3D P-Velocity Model of the Earth's Crust and Mantle

    NASA Astrophysics Data System (ADS)

    Begnaud, M. L.; Ballard, S.; Young, C. J.; Hipp, J. R.; Chang, M.; Encarnacao, A.; Rowe, C. A.; Phillips, W. S.; Steck, L.

    2011-12-01

    To test the hypothesis that high quality 3D Earth models will produce seismic event locations that are more accurate and more precise than currently used 1D and 2/2.5D models, we are developing a global 3D P wave velocity model of the Earth's crust and mantle using seismic tomography. In this paper, we present the most recent version of our model, SALSA3D (SAndia LoS Alamos 3D) version 1.7, and demonstrate its ability to reduce mislocations for a large set of realizations derived from a carefully chosen set of globally-distributed ground truth (GT) events, compared to existing models and/or systems. Our model is derived from the latest version of the GT catalog of P and Pn travel time picks assembled by Los Alamos National Laboratory. To prevent over-weighting due to ray path redundancy and to reduce the computational burden, we cluster rays to produce representative rays. Reduction in the total number of ray paths is ~50%. The model is represented using the triangular tessellation system described by Ballard et al. (2009), which incorporates variable resolution in both the geographic and radial dimensions. For our starting model, we use a simplified layer crustal model derived from the NNSA Unified model in Eurasia and Crust 2.0 model elsewhere, over a uniform ak135 mantle. Sufficient damping is used to reduce velocity adjustments so that ray path changes between iterations are small. We obtain proper model smoothness by using progressive grid refinement, refining the grid only in areas where the data warrant it. In previous versions of SALSA3D, we based this refinement on velocity changes from previous model iterations. For version 1.7, we utilize the diagonal of the model resolution matrix to control where grid refinement occurs, resulting in more consistent and continuous areas of refinement than before. Our approach produces a smooth, multi-resolution model with node density appropriate to both ray coverage and the velocity gradients required by the data. We

  16. Energy cost and body centre of mass' 3D intracycle velocity variation in swimming.

    PubMed

    Figueiredo, Pedro; Barbosa, Tiago M; Vilas-Boas, João Paulo; Fernandes, Ricardo J

    2012-09-01

    The purpose of this study was to examine the relationship between the energy cost (C) and the 3D intracycle velocity variation (IVV; swimming direction--x, vertical--y and lateral--z axes) throughout the 200 m front crawl event. Ten international level swimmers performed a maximal 200 m front crawl swim followed by 50, 100 and 150 m bouts at the same pace as in the 200 m splits. Oxygen consumption was measured during the bouts and blood samples were collected before and after each one. The C was calculated for each 50 m lap as the ratio of the total energy expenditure (three energy pathways) to the distance. A respiratory snorkel and valve system with low hydrodynamic resistance was used to measure pulmonary ventilation and to collect breathing air samples. Two above water and four underwater cameras videotaped the swim bouts and thereafter APAS was used to assess the centre of mass IVV (x, y and z components). The increase in the C was significantly associated with the increase in the IVV in x for the first 50 m lap (R = -0.83, P < 0.01). It is concluded that the IVV relationship with C in a competitive event does not present the direct relationship found in the literature, revealing a great specificity, which suggests that the relation between these two parameters could not be used as a performance predictor in competitive events. PMID:22262010

  17. 3D visualization of endocardial peak velocities during systole and diastole

    NASA Astrophysics Data System (ADS)

    Eusemann, Christian D.; Ritman, Erik L.; Robb, Richard A.

    2002-04-01

    Quantitative assessment of regional heart motion has the potential to provide diagnostic data for assessment of cardiac malfunction. Local heart motion may be obtained with various medical imaging scanners, so the goal is to provide an imaging modality-independent display/analysis technique. In this study, 3D reconstructions of a canine heart before and after infarction were obtained from the Dynamic Spatial Reconstructor (DSR) at 15 time points throughout one cardiac cycle. Deformable models of each time point were created. Through this process regional excursions and velocities in the mesh can be assigned to represent a piece of endocardium, which can be calculated for each time-point interval. These calculations are based on the distance change between a single vertex of the mesh and the model centerline from LV apex to aortic/mitral valve separation. This allows computation of color maps corresponding to regional values of contraction or dilation motion of the endocardium relative to the LV long axis (centerline) during systole and/or diastole. These color maps can be illustrated through model animations and multi view static images. Using functional parametric mappings of disturbances in regional contractility and relaxation facilitates appreciation of the effect of altered structure-to-function relationships in the myocardium.

  18. A Reconstruction Approach for Imaging in 3D Cone Beam Vector Field Tomography

    PubMed Central

    Schuster, T.; Theis, D.; Louis, A. K.

    2008-01-01

    3D cone beam vector field tomography (VFT) aims for reconstructing and visualizing the velocity field of a moving fluid by measuring line integrals of projections of the vector field. The data are obtained by ultrasound measurements along a scanning curve which surrounds the object. From a mathematical point of view, we have to deal with the inversion of the vectorial cone beam transform. Since the vectorial cone beam transform of any gradient vector field with compact support is identically equal to zero, we can only hope to reconstruct the solenoidal part of an arbitrary vector field. In this paper we will at first summarize important properties of the cone beam transform for three-dimensional solenoidal vector fields and then propose a solution approach based on the method of approximate inverse. In this context, we intensively make use of results from scalar 3D computerized tomography. The findings presented in the paper will continuously be illustrated by pictures from first numerical experiments done with exact, simulated data. PMID:19197391

  19. A compact single-camera system for high-speed, simultaneous 3-D velocity and temperature measurements.

    SciTech Connect

    Lu, Louise; Sick, Volker; Frank, Jonathan H.

    2013-09-01

    The University of Michigan and Sandia National Laboratories collaborated on the initial development of a compact single-camera approach for simultaneously measuring 3-D gasphase velocity and temperature fields at high frame rates. A compact diagnostic tool is desired to enable investigations of flows with limited optical access, such as near-wall flows in an internal combustion engine. These in-cylinder flows play a crucial role in improving engine performance. Thermographic phosphors were proposed as flow and temperature tracers to extend the capabilities of a novel, compact 3D velocimetry diagnostic to include high-speed thermometry. Ratiometric measurements were performed using two spectral bands of laser-induced phosphorescence emission from BaMg2Al10O17:Eu (BAM) phosphors in a heated air flow to determine the optimal optical configuration for accurate temperature measurements. The originally planned multi-year research project ended prematurely after the first year due to the Sandia-sponsored student leaving the research group at the University of Michigan.

  20. Velocity Measurement in Carotid Artery: Quantitative Comparison of Time-Resolved 3D Phase-Contrast MRI and Image-based Computational Fluid Dynamics

    PubMed Central

    Sarrami-Foroushani, Ali; Nasr Esfahany, Mohsen; Nasiraei Moghaddam, Abbas; Saligheh Rad, Hamidreza; Firouznia, Kavous; Shakiba, Madjid; Ghanaati, Hossein; Wilkinson, Iain David; Frangi, Alejandro Federico

    2015-01-01

    Background: Understanding hemodynamic environment in vessels is important for realizing the mechanisms leading to vascular pathologies. Objectives: Three-dimensional velocity vector field in carotid bifurcation is visualized using TR 3D phase-contrast magnetic resonance imaging (TR 3D PC MRI) and computational fluid dynamics (CFD). This study aimed to present a qualitative and quantitative comparison of the velocity vector field obtained by each technique. Subjects and Methods: MR imaging was performed on a 30-year old male normal subject. TR 3D PC MRI was performed on a 3 T scanner to measure velocity in carotid bifurcation. 3D anatomical model for CFD was created using images obtained from time-of-flight MR angiography. Velocity vector field in carotid bifurcation was predicted using CFD and PC MRI techniques. A statistical analysis was performed to assess the agreement between the two methods. Results: Although the main flow patterns were the same for the both techniques, CFD showed a greater resolution in mapping the secondary and circulating flows. Overall root mean square (RMS) errors for all the corresponding data points in PC MRI and CFD were 14.27% in peak systole and 12.91% in end diastole relative to maximum velocity measured at each cardiac phase. Bland-Altman plots showed a very good agreement between the two techniques. However, this study was not aimed to validate any of methods, instead, the consistency was assessed to accentuate the similarities and differences between Time-resolved PC MRI and CFD. Conclusion: Both techniques provided quantitatively consistent results of in vivo velocity vector fields in right internal carotid artery (RCA). PC MRI represented a good estimation of main flow patterns inside the vasculature, which seems to be acceptable for clinical use. However, limitations of each technique should be considered while interpreting results. PMID:26793288

  1. Analysis of non linear partially standing waves from 3D velocity measurements

    NASA Astrophysics Data System (ADS)

    Drevard, D.; Rey, V.; Svendsen, Ib; Fraunie, P.

    2003-04-01

    Surface gravity waves in the ocean exhibit an energy spectrum distributed in both frequency and direction of propagation. Wave data collection is of great importance in coastal zones for engineering and scientific studies. In particular, partially standing waves measurements near coastal structures and steep or barred beaches may be a requirement, for instance for morphodynamic studies. The aim of the present study is the analysis of partially standing surface waves icluding non-linear effects. According to 1st order Stokes theory, synchronous measurements of horizontal and vertical velocity components allow calculation of rate of standing waves (Drevard et al, 2003). In the present study, it is demonstrated that for deep water conditions, partially standing 2nd order Stokes waves induced velocity field is still represented by the 1st order solution for the velocity potential contrary to the surface elevation which exhibits harmonic components. For intermediate water depth, harmonic components appear not only in the surface elevation but also in the velocity fields, but their weight remains much smaller, because of the vertical decreasing wave induced motion. For irregular waves, the influence of the spectrum width on the non-linear effects in the analysis is discussed. Keywords: Wave measurements ; reflection ; non-linear effects Acknowledgements: This work was initiated during the stay of Prof. Ib Svendsen, as invited Professor, at LSEET in autumn 2002. This study is carried out in the framework of the Scientific French National Programmes PNEC ART7 and PATOM. Their financial supports are acknowledged References: Drevard, D., Meuret, A., Rey, V. Piazzola, J. And Dolle, A.. (2002). "Partially reflected waves measurements using Acoustic Doppler Velocimeter (ADV)", Submitted to ISOPE 03, Honolulu, Hawaii, May 2003.

  2. 3D P-wave velocity structure of the deep Galicia rifted margin: A first analysis of the Galicia 3D wide-angle seismic dataset

    NASA Astrophysics Data System (ADS)

    Bayrakci, Gaye; Minshull, Timothy A.; Davy, Richard G.; Karplus, Marianne S.; Kaeschen, Dirk; Papenberg, Cord; Krabbenhoeft, Anne; Sawyer, Dale; Reston, Timothy J.; Shillington, Donna J.; Ranero, César R.

    2014-05-01

    Galicia 3D, a reflection-refraction and long offset seismic experiment was carried out from May through September 2013, at the Galicia rifted margin (in the northeast Atlantic Ocean, west of Spain) as a collaboration between US, UK, German and Spanish groups. The 3D multichannel seismic acquisition conducted by R/V Marcus Langseth covered a 64 km by 20 km (1280 km2) zone where the main geological features are the Peridotite Ridge (PR), composed of serpentinized peridotite and thought be upper mantle exhumed to the seafloor during rifting, and the S reflector which has been interpreted to be a low angle detachment fault overlain by fault bounded, rotated, continental crustal blocks. In the 3D box, two airgun arrays of 3300 cu.in. were fired alternately (in flip-flop configuration) every 37.5 m. All shots are recorded by 44 short period four component ocean bottom seismometers (OBS) and 26 ocean bottom hydrophones (OBH) deployed and recovered by R/V Poseidon, as well as four 6 km hydrophone streamers with 12.5 m channel spacing towed by R/V Marcus Langseth. We present the preliminary results of the first arrival time tomography study which is carried out with a subset of the wide-angle dataset, in order to generate a 3D P-wave velocity volume for the entire depth sampled by the reflection data. After the relocation of OBSs and OBHs, an automatic first-arrival time picking approach is applied to a subset of the dataset, which comprises more than 5.5 million source-receiver pairs. Then, the first-arrival times are checked visually, in 3-dimensions. The a priori model used for the first-arrival time tomography is built up using information from previous seismic surveys carried out at the Galicia margin (e.g. ISE, 1997). The FAST algorithm of Zelt and Barton (1998) is used for the first-arrival time inversion. The 3D P-wave velocity volume can be used in interpreting the reflection dataset, as a starting point for migration, to quantify the thinning of the crustal layers

  3. Resolving stellar populations with crowded field 3D spectroscopy

    NASA Astrophysics Data System (ADS)

    Kamann, S.; Wisotzki, L.; Roth, M. M.

    2013-01-01

    We describe a new method of extracting the spectra of stars from observations of crowded stellar fields with integral field spectroscopy (IFS). Our approach extends the well-established concept of crowded field photometry in images into the domain of 3-dimensional spectroscopic datacubes. The main features of our algorithm follow. (1) We assume that a high-fidelity input source catalogue already exists, e.g. from HST data, and that it is not needed to perform sophisticated source detection in the IFS data. (2) Source positions and properties of the point spread function (PSF) vary smoothly between spectral layers of the datacube, and these variations can be described by simple fitting functions. (3) The shape of the PSF can be adequately described by an analytical function. Even without isolated PSF calibrator stars we can therefore estimate the PSF by a model fit to the full ensemble of stars visible within the field of view. (4) By using sparse matrices to describe the sources, the problem of extracting the spectra of many stars simultaneously becomes computationally tractable. We present extensive performance and validation tests of our algorithm using realistic simulated datacubes that closely reproduce actual IFS observations of the central regions of Galactic globular clusters. We investigate the quality of the extracted spectra under the effects of crowding with respect to the resulting signal-to-noise ratios (S/N) and any possible changes in the continuum level, as well as with respect to absorption line spectral parameters, radial velocities, and equivalent widths. The main effect of blending between two nearby stars is a decrease in the S/N in their spectra. The effect increases with the crowding in the field in a way that the maximum number of stars with useful spectra is always ~0.2 per spatial resolution element. This balance breaks down when exceeding a total source density of one significantly detected star per resolution element. We also explore the

  4. Dynamic scattering theory for dark-field electron holography of 3D strain fields.

    PubMed

    Lubk, Axel; Javon, Elsa; Cherkashin, Nikolay; Reboh, Shay; Gatel, Christophe; Hÿtch, Martin

    2014-01-01

    Dark-field electron holography maps strain in crystal lattices into reconstructed phases over large fields of view. Here we investigate the details of the lattice strain-reconstructed phase relationship by applying dynamic scattering theory both analytically and numerically. We develop efficient analytic linear projection rules for 3D strain fields, facilitating a straight-forward calculation of reconstructed phases from 3D strained materials. They are used in the following to quantify the influence of various experimental parameters like strain magnitude, specimen thickness, excitation error and surface relaxation. PMID:24012934

  5. Lateral Crustal Velocity Variations across the Andean Foreland in San Juan, Argentina from the JHD Analysis and 3D P and S Velocity inversion

    NASA Astrophysics Data System (ADS)

    Asmerom, B. B.; Chiu, J.; Pujol, J.; Smalley, R.

    2010-12-01

    Lateral crustal velocity variations across the Andean Foreland in San Juan Argentina are explored by joint hypocentral determination (JHD) analysis and 3D velocity inversion. JHD results show consistent positive station corrections beneath Precordillera and negative station corrections beneath Pie de Palo, corresponding to regions of low and high velocity, respectively. These observations are supported by the results from the 3D velocity inversion. A 20% increase in velocity is observed from the Precordilleras in the west to Pie de Palo in the east. The tomography result also reveals a narrow east dipping and NNE trending high velocity anomalous zone bisecting the southern half of Pie de Palo. This anomalous zone was previously identified by a magnetic study and was interpreted to represent the structure corresponding to the Grenvillian Precordillera-Pie de Palo tectonic boundary zone. Finally, P and S station corrections are calculated from the synthetic travel time obtained by using the resultant 3D P- and S- wave velocity model. The observed pattern and magnitude of the P- and S-wave station corrections are recovered successfully from the synthetic calculation, indicating that the resultant 3D velocity model is close to the real earth structure in the Andean Foreland region. Relocation of all intermediate events from the flat subducting slab using this newly acquired 3D velocity model shows a significant change in the slab geometry. The relocated hypocenter distribution is more clustered than previous studies obtained using a 1D model. The slab is simply flat and it resumes a normal subduction angle towards the east of the study area.

  6. SALSA3D - A Global 3D P-Velocity Model of the Earth's Crust and Mantle for Improved Event Location

    NASA Astrophysics Data System (ADS)

    Ballard, S.; Begnaud, M. L.; Young, C. J.; Hipp, J. R.; Chang, M.; Encarnacao, A. V.; Rowe, C. A.; Phillips, W. S.; Steck, L.

    2010-12-01

    To test the hypothesis that high quality 3D Earth models will produce seismic event locations which are more accurate and more precise, we are developing a global 3D P wave velocity model of the Earth’s crust and mantle using seismic tomography. In this paper, we present the most recent version of our model, SALSA3D version 1.5, and demonstrate its ability to reduce mislocations for a large set of realizations derived from a carefully chosen set of globally-distributed ground truth events. Our model is derived from the latest version of the Ground Truth (GT) catalog of P and Pn travel time picks assembled by Los Alamos National Laboratory. To prevent over-weighting due to ray path redundancy and to reduce the computational burden, we cluster rays to produce representative rays. Reduction in the total number of ray paths is ~50%. The model is represented using the triangular tessellation system described by Ballard et al. (2009), which incorporates variable resolution in both the geographic and radial dimensions.. For our starting model, we use a simplified two layer crustal model derived from the Crust 2.0 model over a uniform AK135 mantle. Sufficient damping is used to reduce velocity adjustments so that ray path changes between iterations are small. We obtain proper model smoothness by using progressive grid refinement, refining the grid only around areas with significant velocity changes from the starting model. At each grid refinement level except the last one we limit the number of iterations to prevent convergence thereby preserving aspects of broad features resolved at coarser resolutions. Our approach produces a smooth, multi-resolution model with node density appropriate to both ray coverage and the velocity gradients required by the data. This scheme is computationally expensive, so we use a distributed computing framework based on the Java Parallel Processing Framework, providing us with ~400 processors. Resolution of our model is assessed using a

  7. Automated objective characterization of visual field defects in 3D

    NASA Technical Reports Server (NTRS)

    Fink, Wolfgang (Inventor)

    2006-01-01

    A method and apparatus for electronically performing a visual field test for a patient. A visual field test pattern is displayed to the patient on an electronic display device and the patient's responses to the visual field test pattern are recorded. A visual field representation is generated from the patient's responses. The visual field representation is then used as an input into a variety of automated diagnostic processes. In one process, the visual field representation is used to generate a statistical description of the rapidity of change of a patient's visual field at the boundary of a visual field defect. In another process, the area of a visual field defect is calculated using the visual field representation. In another process, the visual field representation is used to generate a statistical description of the volume of a patient's visual field defect.

  8. Preflare magnetic and velocity fields

    NASA Technical Reports Server (NTRS)

    Hagyard, M. J.; Gaizauskas, V.; Chapman, G. A.; Deloach, A. C.; Gary, G. A.; Jones, H. P.; Karpen, J. T.; Martres, M.-J.; Porter, J. G.; Schmeider, B.

    1986-01-01

    A characterization is given of the preflare magnetic field, using theoretical models of force free fields together with observed field structure to determine the general morphology. Direct observational evidence for sheared magnetic fields is presented. The role of this magnetic shear in the flare process is considered within the context of a MHD model that describes the buildup of magnetic energy, and the concept of a critical value of shear is explored. The related subject of electric currents in the preflare state is discussed next, with emphasis on new insights provided by direct calculations of the vertical electric current density from vector magnetograph data and on the role of these currents in producing preflare brightenings. Results from investigations concerning velocity fields in flaring active regions, describing observations and analyses of preflare ejecta, sheared velocities, and vortical motions near flaring sites are given. This is followed by a critical review of prevalent concepts concerning the association of flux emergence with flares

  9. Integration of real-time 3D capture, reconstruction, and light-field display

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaoxing; Geng, Zheng; Li, Tuotuo; Pei, Renjing; Liu, Yongchun; Zhang, Xiao

    2015-03-01

    Effective integration of 3D acquisition, reconstruction (modeling) and display technologies into a seamless systems provides augmented experience of visualizing and analyzing real objects and scenes with realistic 3D sensation. Applications can be found in medical imaging, gaming, virtual or augmented reality and hybrid simulations. Although 3D acquisition, reconstruction, and display technologies have gained significant momentum in recent years, there seems a lack of attention on synergistically combining these components into a "end-to-end" 3D visualization system. We designed, built and tested an integrated 3D visualization system that is able to capture in real-time 3D light-field images, perform 3D reconstruction to build 3D model of the objects, and display the 3D model on a large autostereoscopic screen. In this article, we will present our system architecture and component designs, hardware/software implementations, and experimental results. We will elaborate on our recent progress on sparse camera array light-field 3D acquisition, real-time dense 3D reconstruction, and autostereoscopic multi-view 3D display. A prototype is finally presented with test results to illustrate the effectiveness of our proposed integrated 3D visualization system.

  10. Applications of detailed 3D P-wave velocity crustal model in Poland for local, regional and global seismic tomography

    NASA Astrophysics Data System (ADS)

    Polkowski, Marcin; Grad, Marek

    2015-04-01

    The 3D P-wave seismic velocity model was obtained by combining data from multiple studies during past 50 years. Data sources included refraction seismology, reflection seismology, geological boreholes, vertical seismic profiling, magnetotellurics and gravimetry. Use of many data sources allowed creation of detailed 3D P-wave velocity model that reaches to depth of 60 km and includes 6-layers of sediments and 3-layers of the crust. Purpose of this study is to analyze how 3D model influences local (accuracy of location and source time estimation for local events), regional (identification of wide-angle seismic phases) and global (teleseismic tomography) seismic travel times. Additionally we compare results of forward seismic wave propagation with signals observed on short period and broadband stations. National Science Centre Poland provided financial support for this work by NCN grant DEC-2011/02/A/ST10/00284.

  11. 3-D Waveguide Effects of Topographical Structural Variation on Full Waveform Propagation: 3-D Finite Difference Modeling Comparisons with Field Data From Yuma Proving Ground, Arizona

    NASA Astrophysics Data System (ADS)

    Anderson, T. S.; Miller, R.; Greenfield, R.; Fisk, D.

    2002-12-01

    The propagation of seismic waves through regions of complex topography is not thoroughly understood. Surface waves, are of particular interest, as they are large in amplitude and can characterize the source depth, magnitude, and frequency content. The amplitude and frequency content of seismic waves that propagate in regions with large topographical variations are affected by both the scattering and blockage of the wave energy. The ability to predict the 3-d scattering due to topography will improve the understanding of both regional scale surface wave magnitudes, and refine surface wave discriminants as well as at the local scale (<2 km ) where it will aid in the development of rule of thumb guide lines for array sensor placement for real time sensing technologies. Ideally, when validating the numerical accuracy of a propagation model against field data, the input geologic parameters would be known and thus eliminates geology as a source of error in the calculation. In March of 2001, Kansas Geological Survey (KGS) performed a detailed seismic site characterization at the Smart Weapons Test Range, Yuma Proving Ground, Arizona. The result of the KGS characterization study is a high-resolution 3-d model that is used in our seismic simulations. The velocities Vs, Vp are calculated by tomography and refraction, attenuation coefficients estimated from the surface wave and from p-waves and are provided in a model with attributes resolved in 3-d to 0.5 meters. In the present work, we present comparisons of synthetic data with seismic data collected at the Smart Weapons Test Range to benchmark the accuracy achieved in simulating 3-d wave propagation in the vicinity of a topographical anomaly (trench). Synthetic seismograms are generated using a 3-d 8th order staggered grid visco-elastic finite difference code that accounts for topography. The geologic model is based on the Yuma site characterization. The size of these calculations required use of the DoD High Performance

  12. Kriging interpolating cosmic velocity field

    NASA Astrophysics Data System (ADS)

    Yu, Yu; Zhang, Jun; Jing, Yipeng; Zhang, Pengjie

    2015-10-01

    Volume-weighted statistics of large-scale peculiar velocity is preferred by peculiar velocity cosmology, since it is free of the uncertainties of galaxy density bias entangled in observed number density-weighted statistics. However, measuring the volume-weighted velocity statistics from galaxy (halo/simulation particle) velocity data is challenging. Therefore, the exploration of velocity assignment methods with well-controlled sampling artifacts is of great importance. For the first time, we apply the Kriging interpolation to obtain the volume-weighted velocity field. Kriging is a minimum variance estimator. It predicts the most likely velocity for each place based on the velocity at other places. We test the performance of Kriging quantified by the E-mode velocity power spectrum from simulations. Dependences on the variogram prior used in Kriging, the number nk of the nearby particles to interpolate, and the density nP of the observed sample are investigated. First, we find that Kriging induces 1% and 3% systematics at k ˜0.1 h Mpc-1 when nP˜6 ×1 0-2(h-1 Mpc )-3 and nP˜6 ×1 0-3(h-1 Mpc )-3 , respectively. The deviation increases for decreasing nP and increasing k . When nP≲6 ×1 0-4(h-1 Mpc )-3 , a smoothing effect dominates small scales, causing significant underestimation of the velocity power spectrum. Second, increasing nk helps to recover small-scale power. However, for nP≲6 ×1 0-4(h-1 Mpc )-3 cases, the recovery is limited. Finally, Kriging is more sensitive to the variogram prior for a lower sample density. The most straightforward application of Kriging on the cosmic velocity field does not show obvious advantages over the nearest-particle method [Y. Zheng, P. Zhang, Y. Jing, W. Lin, and J. Pan, Phys. Rev. D 88, 103510 (2013)] and could not be directly applied to cosmology so far. However, whether potential improvements may be achieved by more delicate versions of Kriging is worth further investigation.

  13. A New Regional 3-D Velocity Model of the India-Pakistan Region for Improved Event Location Accuracy

    NASA Astrophysics Data System (ADS)

    Reiter, D.; Vincent, C.; Johnson, M.

    2001-05-01

    A 3-D velocity model for the crust and upper mantle (WINPAK3D) has been developed to improve regional event location in the India-Pakistan region. Results of extensive testing demonstrate that the model improves location accuracy for this region, specifically for the case of small regionally recorded events, for which teleseismic data may not be available. The model was developed by integrating the results of more than sixty previous studies related to crustal velocity structure in the region. We evaluated the validity of the 3-D model using the following methods: (1) cross validation analysis for a variety of events, (2) comparison of model determined hypocenters with known event location, and (3) comparison of model-derived and empirically-derived source-specific station corrections (SSSC) generated for the International Monitoring System (IMS) auxiliary seismic station located at Nilore. The 3-D model provides significant improvement in regional location compared to both global and regional 1-D models in this area of complex structural variability. For example, the epicenter mislocation for an event with a well known location was only 6.4 km using the 3-D model, compared with a mislocation of 13.0 km using an average regional 1-D model and 15.1 km for the IASPEI91 model. We will present these and other results to demonstrate that 3-D velocity models are essential to improving event location accuracy in regions with complicated crustal geology and structures. Such 3-D models will be a prerequisite for achieving improved location accuracies for regions of high monitoring interest.

  14. 3D Numerical simulation of high current vacuum arc in realistic magnetic fields considering anode evaporation

    NASA Astrophysics Data System (ADS)

    Wang, Lijun; Huang, Xiaolong; Jia, Shenli; Deng, Jie; Qian, Zhonghao; Shi, Zongqian; Schellenkens, H.; Godechot, X.

    2015-06-01

    A time-dependent 3D numerical model considering anode evaporation is developed for the high current vacuum arc (VA) under a realistic spatial magnetic field. The simulation work contains steady state 3D numerical simulation of high current VA considering anode evaporation at nine discrete moments of first half wave of 50 Hz AC current, transient numerical simulation of anode activity, and realistic spatial magnetic field calculation of commercial cup-shaped electrodes. In the simulation, contact opening and arc diffusion processes are also considered. Due to the effect of electrode slots, the simulation results of magnetic field and temperature of anode plate exhibit six leaves shape (SLS). During 6-8 ms, the strong evaporation of anode surface seriously influence the parameter distributions of VA. Ions emitted from anode penetrate into arc column and the axial velocity distribution on the anode side exhibits SLS. The ions emitted from anode surface have the same temperature with anode surface, which cool the arc plasma and lead to a relative low temperature area formed. The seriously evaporation of anode leads to the accumulation of ions near the anode, and then the current density is more uniform.

  15. Temporal Evolution of the 3-D Flow Field In a Mixing Tank with a Two-Bladed Impeller

    NASA Astrophysics Data System (ADS)

    Choi, Woong-Chul; Guezennec, Yann G.

    1998-11-01

    The evolution of the 3-D flow field inside a cylindrical mixing vessel was measured using 3-D Cinematic Particle Tracking Velocimetry. The mixing vessel consisted of a cylindrical chamber with a two-bladed impeller axially centered in the vessel. The impeller was a simple paddle wheel-type and its height in the vessel could be externally adjusted. The fluid inside the chamber was seeded by small neutrally buoyant particles. The entire vessel volume was illuminated by a high-power, collimated strobe light located under the vessel and the particle motion was imaged by a pair of synchronized high-speed (up to 500 fps) digital cameras. Prior to the actual experiments, an in situ calibration of the cameras was performed to automatically account for the optical distortion resulting from the curved vessel boundaries and index of refraction mismatch. The long, high-speed video sequences were analyzed using the FloDyne(tm) 3-D Particle Tracking software. This typically resulted in 500-600 instantaneous 3-D velocity vectors over the entire vessel. The image sequences were then processed for a large number of impeller rotations (50, typically). The resulting velocity fields were then post-processed to obtain the evolution of the phase-averaged 3-D velocity field as well as estimates of the intrinsic turbulence intensities. Animation of the reconstructed 3-D flow fields will be shown. Under some geometrical configurations of the impeller at low Reynolds numbers, the results show the presence of quasi-stable recirculating regions inhibiting the overall mixing.

  16. Microseismic monitoring of soft-rock landslide: contribution of a 3D velocity model for the location of seismic sources.

    NASA Astrophysics Data System (ADS)

    Floriane, Provost; Jean-Philippe, Malet; Cécile, Doubre; Julien, Gance; Alessia, Maggi; Agnès, Helmstetter

    2015-04-01

    Characterizing the micro-seismic activity of landslides is an important parameter for a better understanding of the physical processes controlling landslide behaviour. However, the location of the seismic sources on landslides is a challenging task mostly because of (a) the recording system geometry, (b) the lack of clear P-wave arrivals and clear wave differentiation, (c) the heterogeneous velocities of the ground. The objective of this work is therefore to test whether the integration of a 3D velocity model in probabilistic seismic source location codes improves the quality of the determination especially in depth. We studied the clay-rich landslide of Super-Sauze (French Alps). Most of the seismic events (rockfalls, slidequakes, tremors...) are generated in the upper part of the landslide near the main scarp. The seismic recording system is composed of two antennas with four vertical seismometers each located on the east and west sides of the seismically active part of the landslide. A refraction seismic campaign was conducted in August 2014 and a 3D P-wave model has been estimated using the Quasi-Newton tomography inversion algorithm. The shots of the seismic campaign are used as calibration shots to test the performance of the different location methods and to further update the 3D velocity model. Natural seismic events are detected with a semi-automatic technique using a frequency threshold. The first arrivals are picked using a kurtosis-based method and compared to the manual picking. Several location methods were finally tested. We compared a non-linear probabilistic method coupled with the 3D P-wave model and a beam-forming method inverted for an apparent velocity. We found that the Quasi-Newton tomography inversion algorithm provides results coherent with the original underlaying topography. The velocity ranges from 500 m.s-1 at the surface to 3000 m.s-1 in the bedrock. For the majority of the calibration shots, the use of a 3D velocity model

  17. 3D fingerprint imaging system based on full-field fringe projection profilometry

    NASA Astrophysics Data System (ADS)

    Huang, Shujun; Zhang, Zonghua; Zhao, Yan; Dai, Jie; Chen, Chao; Xu, Yongjia; Zhang, E.; Xie, Lili

    2014-01-01

    As an unique, unchangeable and easily acquired biometrics, fingerprint has been widely studied in academics and applied in many fields over the years. The traditional fingerprint recognition methods are based on the obtained 2D feature of fingerprint. However, fingerprint is a 3D biological characteristic. The mapping from 3D to 2D loses 1D information and causes nonlinear distortion of the captured fingerprint. Therefore, it is becoming more and more important to obtain 3D fingerprint information for recognition. In this paper, a novel 3D fingerprint imaging system is presented based on fringe projection technique to obtain 3D features and the corresponding color texture information. A series of color sinusoidal fringe patterns with optimum three-fringe numbers are projected onto a finger surface. From another viewpoint, the fringe patterns are deformed by the finger surface and captured by a CCD camera. 3D shape data of the finger can be obtained from the captured fringe pattern images. This paper studies the prototype of the 3D fingerprint imaging system, including principle of 3D fingerprint acquisition, hardware design of the 3D imaging system, 3D calibration of the system, and software development. Some experiments are carried out by acquiring several 3D fingerprint data. The experimental results demonstrate the feasibility of the proposed 3D fingerprint imaging system.

  18. Mapping Faults from 3-D Tomographic Velocity Model using Image Processing / Computer Vision Algorithms: Application to Northern Cascadia

    NASA Astrophysics Data System (ADS)

    Ramachandran, K.

    2011-12-01

    Three dimensional velocity models constructed through seismic tomography are seldom digitally processed further for imaging structural features. A study conducted to evaluate the potential for imaging subsurface discontinuities in horizontal and vertical direction from three dimensional velocity models using image processing/computer vision techniques has provided significant results. Three-dimensional velocity models constructed through tomographic inversion of active source and/or earthquake traveltime data are generally built from an initial 1-D velocity model that varies only with depth. Regularized tomographic inversion algorithms impose constraints on the roughness of the model that help to stabilize the inversion process. Final velocity models obtained from regularized tomographic inversions have smooth three-dimensional structures that are required by the data. Final velocity models are usually analyzed and interpreted either as a perturbation velocity model or as an absolute velocity model. Compared to perturbation velocity model, absolute velocity model has an advantage of providing constraints on lithology. Both velocity models lack the ability to provide sharp constraints on subsurface faults. However, results from the analysis of the 3-D velocity model from northern Cascadia using Roberts, Prewitt, Sobel, and Canny operators show that subsurface faults that are not clearly interpretable from velocity model plots can be identified through this approach. This analysis resulted in inferring the locations of Tacoma Fault, Seattle Fault, Southern Whidbey Island Fault, and Darrington Devils Mountain fault much clearly. The Coast Range Boundary Fault, previously hypothesized on the basis of sedimentological and tectonic observations is inferred clearly from processed images. Many of the fault locations so imaged correlate with earthquake hypocenters indicating their seismogenic nature.

  19. Segment-interaction in sprint start: Analysis of 3D angular velocity and kinetic energy in elite sprinters.

    PubMed

    Slawinski, J; Bonnefoy, A; Ontanon, G; Leveque, J M; Miller, C; Riquet, A; Chèze, L; Dumas, R

    2010-05-28

    The aim of the present study was to measure during a sprint start the joint angular velocity and the kinetic energy of the different segments in elite sprinters. This was performed using a 3D kinematic analysis of the whole body. Eight elite sprinters (10.30+/-0.14s 100 m time), equipped with 63 passive reflective markers, realised four maximal 10 m sprints start on an indoor track. An opto-electronic Motion Analysis system consisting of 12 digital cameras (250 Hz) was used to collect the 3D marker trajectories. During the pushing phase on the blocks, the 3D angular velocity vector and its norm were calculated for each joint. The kinetic energy of 16 segments of the lower and upper limbs and of the total body was calculated. The 3D kinematic analysis of the whole body demonstrated that joints such as shoulders, thoracic or hips did not reach their maximal angular velocity with a movement of flexion-extension, but with a combination of flexion-extension, abduction-adduction and internal-external rotation. The maximal kinetic energy of the total body was reached before clearing block (respectively, 537+/-59.3 J vs. 514.9+/-66.0 J; p< or =0.01). These results suggested that a better synchronization between the upper and lower limbs could increase the efficiency of pushing phase on the blocks. Besides, to understand low interindividual variances in the sprint start performance in elite athletes, a 3D complete body kinematic analysis shall be used. PMID:20226465

  20. Increasing the depth of field in Multiview 3D images

    NASA Astrophysics Data System (ADS)

    Lee, Beom-Ryeol; Son, Jung-Young; Yano, Sumio; Jung, Ilkwon

    2016-06-01

    A super-multiview condition simulator which can project up to four different view images to each eye is introduced. This simulator with the image having both disparity and perspective informs that the depth of field (DOF) will be extended to more than the default DOF values as the number of simultaneously but separately projected different view images to each eye increase. The DOF range can be extended to near 2 diopters with the four simultaneous view images. However, the DOF value increments are not prominent as the image with both disparity and perspective with the image with disparity only.

  1. Heat pulse propagation is 3-D chaotic magnetic fields

    NASA Astrophysics Data System (ADS)

    Del-Castillo-Negrete, D.; Blazevski, D.

    2013-10-01

    Perturbative transport studies provide valuable time dependent information to construct and test transport models in magnetically confined plasmas. In these studies, the transient response of the plasma to externally applied small perturbations is followed in time. Here we present a numerical study of the radial propagation of edge heat pulse perturbations in the presence of 3-dimensional chaotic magnetic fields in cylindrical geometry. Based on the strong transport anisotropy encountered in magnetized plasmas (χ∥ /χ⊥ ~1010 in fusion plasmas, where χ∥ and χ⊥ are the parallel and perpendicular conductivities) we limit attention to the extreme anisotropic, purely parallel, χ⊥ = 0 , case. Using the Lagrangian-Green's function method we study the dependence of the pulse speed and radial penetration on the level of stochasticity of the magnetic field in regular, and reversed magnetic shear configurations. Of particular interest is the slowing down of the heat pulse due to weak chaos, islands, and shearless cantori. Work supported by the USA Department of Energy.

  2. On the critical one-component velocity regularity criteria to 3-D incompressible MHD system

    NASA Astrophysics Data System (ADS)

    Liu, Yanlin

    2016-05-01

    Let (u , b) be a smooth enough solution of 3-D incompressible MHD system. We prove that if (u , b) blows up at a finite time T*, then for any p ∈ ] 4 , ∞ [, there holds ∫0T* (‖u3(t‧) ‖ H ˙ 1/2 +2/p p + ‖b(t‧) ‖ H ˙ 1/2 +2/p p) dt‧ = ∞. We remark that all these quantities are in the critical regularity of the MHD system.

  3. 3-D explosions: a meditation on rotation (and magnetic fields)

    NASA Astrophysics Data System (ADS)

    Wheeler, J. C.

    This is the text of an introduction to a workshop on asymmetric explosions held in Austin in June, 2003. The great progress in supernova research over thirty-odd years is briefly reviewed. The context in which the meeting was called is then summarized. The theoretical success of the intrinsically multidimensional delayed detonation paradigm in explaining the nature of Type Ia supernovae coupled with new techniques of observations in the near IR and with spectropolarimetry promise great advances in understanding binary progenitors, the explosion physics, and the ever more accurate application to cosmology. Spectropolarimetry has also revealed the strongly asymmetric nature of core collapse and given valuable perspectives on the supernova - gamma-ray burst connection. The capability of the magneto-rotational instability to rapidly create strong toroidal magnetic fields in the core collapse ambiance is outlined. This physics may be the precursor to driving MHD jets that play a role in asymmetric supernovae. Welcome to the brave new world of three-dimensional explosions!

  4. 3D P-Wave Velocity Structure of the Crust and Relocation of Earthquakes in 21 the Lushan Source Area

    NASA Astrophysics Data System (ADS)

    Yu, X.; Wang, X.; Zhang, W.

    2014-12-01

    The double difference seismic tomography method is applied to the absolute first arrival P wave arrival times and high quality relative P arrival times of the Lushan seismic sequence to determine the detailed crustal 3D P wave velocity structure and the hypocenter parameters in the Lushan seismic area. The results show that the Lushan mainshock locates at 30.28 N, 103.98 E, with the depth of 16.38 km. The leading edge of aftershock in the northeast of mainshock present a spade with a steep dip angle, the aftershocks' extended length is about 12 km. In the southwest of the Lushan mainshock, the leading edge of aftershock in low velocity zone slope gently, the aftershocks' extended length is about 23 km. The P wave velocity structure of the Lushan seismic area shows obviously lateral heterogeneity. The P wave velocity anomalies represent close relationship with topographic relief and geological structure. In Baoxing area the complex rocks correspond obvious high-velocity anomalies extending down to 15 km depth,while the Cenozoic rocks are correlated with low-velocity anomalies. Our high-resolution tomographic model not only displays the general features contained in the previous models, but also reveals some new features. An obvious high-velocity anomaly is visible in Daxing area. The high-velocity anomalies beneath Baoxing and Daxing connect each other in 10 km depth, which makes the contrast between high and low velocity anomalies more sharp. Above 20 km depth the velocity structure in southwest and northeast segment of the mainshock shows a big difference: low-velocity anomalies are dominated the southwest segment, while high-velocity anomalies rule the northeast segment. The Lushan mainshock locates at the leading edge of a low-velocity anomaly surrounded by the Baoxing and Daxing high-velocity anomalies. The Lushan aftershocks in southwest are distributed in low-velocity anomalies or the transition belt: the footwall represents low-velocity anomalies, while

  5. 3D defect detection using optical wide-field microscopy

    NASA Astrophysics Data System (ADS)

    Tympel, Volker; Schaaf, Marko; Srocka, Bernd

    2007-06-01

    We report a method to detect signed differences in two similar data sets representing 3-dimensional intensity profiles recorded by optical wide-field microscopes. The signed differences describe missing or unexpected intensity values, defined as defects. In technical applications like wafer and mask inspection, data sets often represent surfaces. The reported method is able to describe the size and position especially in relation to the neighboring surface and is called Three-Dimension-Aberration (TDA)-Technology. To increase the tool performance and to handle different sizes of defects a scaled bottom-up method is implemented and started with high reduced data sets for the search of large defects. Each analysis contains three steps. The first step is a correlation to calculate the displacement vector between the similar data sets. In the second step a new data set is created. The new data set consists of intensity differences. Extreme values in the data set represent the position of defects. By the use of linear and non-linear filters the stability of detection can be improved. If all differences are below a threshold the bottom-up method starts with the next larger scaled data set. In the other case it is assumed that the defect is detected and step three starts with the detection of the convex hull of the defect and the search of the neighboring surface. As a result the defect is described by a parameter set including the relative position. Because of the layered structure of the data set and the bottom-up technique the method is suitable for multi-core processor architectures.

  6. Coloring 3D line fields using Boy's real projective plane immersion.

    PubMed

    Demiralp, Cağatay; Hughes, John F; Laidlaw, David H

    2009-01-01

    We introduce a new method for coloring 3D line fields and show results from its application in visualizing orientation in DTI brain data sets. The method uses Boy's surface, an immersion of RP2 in 3D. This coloring method is smooth and one-to-one except on a set of measure zero, the double curve of Boy's surface. PMID:19834221

  7. 3-D Velocity Structure of Southwestern British Columbia and Northern Washington

    NASA Astrophysics Data System (ADS)

    Ramachandran, K.; Ramachandran, K.; Spence, G. D.; Dosso, S.; Hyndman, R. D.; Hyndman, R. D.; Brocher, T. M.; Fisher, M. M.

    2001-12-01

    A seismic tomography analysis in S.W. British Columbia and N. Washington has been used to define the velocity structure of the forearc crust and underlying subducting Juan de Fuca plate, and to obtain precise earthquake locations. First arrival travel-times from earthquakes and from the large airgun array used in the `Seismic Hazards Investigation of Puget Sound' (SHIPS) 1998 experiment, were simultaneously inverted for hypocentral parameters and velocity structure. Approximately 16,000 picks from 1,400 earthquakes recorded at 46 permanent stations, and 35,000 picks from the SHIPS experiment were used in the inversion. The velocity model was parameterized in the forward/inverse step by a node/cell spacing of 3 X 3 X 3 km over a volume of 360 X 450 X 93 km depth. The starting and final RMS travel time misfits were 479 ms and 120 ms respectively. Checkerboard tests conducted on the final velocity model imply good lateral resolution ranging from 30 to 50 km. The SHIPS airgun data mainly constrained the upper ~12 km and the earthquake data the deeper structure. The high velocity mafic Crescent Terrane that dips beneath the margin is well mapped in the velocity model on a regional scale. Its thickness beneath southern Vancouver Island is interpreted to reach ~20 km. Three high velocity structures above the subducting Juan de Fuca plate, having mafic to ultramafic velocities of 7.25-7.5 km/s, occur beneath southern Vancouver Island and Puget Sound at a depth of ~25 km. They may be associated with deeper parts of the Crescent Terrane, or with structures such as seamounts on the subducting Juan de Fuca plate. At the southern tip of Vancouver Islands, the Leech River Fault, Southern Whidbey Island Fault, and the Devils Mountain Fault appear to correlate with mapped seismicity. The subducting Juan de Fuca plate is well mapped beneath southern Vancouver Island, Olympic Peninsula, Strait of Georgia, and Puget Sound. The velocity model identifies the steepening dip in the

  8. A 3-D shear velocity model of the southern North American and Caribbean plates from ambient noise and earthquake tomography

    NASA Astrophysics Data System (ADS)

    Gaite, B.; Villaseñor, A.; Iglesias, A.; Herraiz, M.; Jiménez-Munt, I.

    2015-02-01

    We use group velocities from earthquake tomography together with group and phase velocities from ambient noise tomography (ANT) of Rayleigh waves to invert for the 3-D shear-wave velocity structure (5-70 km) of the Caribbean (CAR) and southern North American (NAM) plates. The lithospheric model proposed offers a complete image of the crust and uppermost-mantle with imprints of the tectonic evolution. One of the most striking features inferred is the main role of the Ouachita-Marathon-Sonora orogeny front on the crustal seismic structure of the NAM plate. A new imaged feature is the low crustal velocities along the USA-Mexico border. The model also shows a break of the east-west mantle velocity dichotomy of the NAM and CAR plates beneath the Isthmus of the Tehuantepec and the Yucatan Block. High upper-mantle velocities along the Mesoamerican Subduction Zone coincide with inactive volcanic areas while the lowest velocities correspond to active volcanic arcs and thin lithospheric mantle regions.

  9. Modeling and validation of a 3D velocity structure for the Santa Clara Valley, California, for seismic-wave simulations

    USGS Publications Warehouse

    Hartzell, S.; Harmsen, S.; Williams, R.A.; Carver, D.; Frankel, A.; Choy, G.; Liu, P.-C.; Jachens, R.C.; Brocher, T.M.; Wentworth, C.M.

    2006-01-01

    A 3D seismic velocity and attenuation model is developed for Santa Clara Valley, California, and its surrounding uplands to predict ground motions from scenario earthquakes. The model is developed using a variety of geologic and geophysical data. Our starting point is a 3D geologic model developed primarily from geologic mapping and gravity and magnetic surveys. An initial velocity model is constructed by using seismic velocities from boreholes, reflection/refraction lines, and spatial autocorrelation microtremor surveys. This model is further refined and the seismic attenuation is estimated through waveform modeling of weak motions from small local events and strong-ground motion from the 1989 Loma Prieta earthquake. Waveforms are calculated to an upper frequency of 1 Hz using a parallelized finite-difference code that utilizes two regions with a factor of 3 difference in grid spacing to reduce memory requirements. Cenozoic basins trap and strongly amplify ground motions. This effect is particularly strong in the Evergreen Basin on the northeastern side of the Santa Clara Valley, where the steeply dipping Silver Creek fault forms the southwestern boundary of the basin. In comparison, the Cupertino Basin on the southwestern side of the valley has a more moderate response, which is attributed to a greater age and velocity of the Cenozoic fill. Surface waves play a major role in the ground motion of sedimentary basins, and they are seen to strongly develop along the western margins of the Santa Clara Valley for our simulation of the Loma Prieta earthquake.

  10. The effect of sliding velocity on chondrocytes activity in 3D scaffolds.

    PubMed

    Wimmer, Markus A; Alini, Mauro; Grad, Sibylle

    2009-03-11

    Sliding motion and shear are important mediators for the synthesis of cartilage matrix and surface molecules. This study investigated the effects of velocity magnitude and motion path on the response of bovine chondrocytes cultured in polyurethane scaffolds and subjected to oscillation against a ceramic ball. In order to vary velocity magnitude, the ball oscillated +/-25 degrees at 0.01, 0.1, and 1Hz to generate 0.28, 2.8, and 28mm/s, respectively. The median velocity of these 'open' motion trajectories was tested against 'closed' motion trajectories in that the scaffold oscillated +/-20 degrees against the ball at 1Hz, reaching 2.8mm/s. Constructs were loaded twice a day for 1h over 5 days. Gene expression of cartilage oligomeric matrix protein (COMP), proteoglycan 4 (PRG4, lubricin), and hyaluronan synthase 1 (HAS1) and release of COMP, PRG4, and hyaluronan (HA) were analyzed. Velocity magnitude determined both gene expression and release of target molecules. Using regression analysis, there was a positive and significant relationship with all outcome variables. However, only COMP reacted significantly at 0.28mm/s, while all other measured variables were considerably up-regulated at 28mm/s. Motion path characteristics affected COMP, but not PRG4 and HAS1/HA. To conclude, velocity magnitude is a critical determinant for cellular responses in tissue engineered cartilage constructs. The motion type also plays a role. However, different molecules are affected in different ways. A molecule specific velocity threshold appears necessary to induce a significant response. This should be considered in further studies investigating the effects of continuous or intermittent motion. PMID:19152917

  11. 3D Seismic Velocity Structure in the Rupture Area of the 2010 Maule Mw=8.8 Earthquake

    NASA Astrophysics Data System (ADS)

    Hicks, S. P.; Rietbrock, A.; Ryder, I. M.; Nippress, S.; Haberland, C. A.

    2011-12-01

    The 2010 Mw=8.8 Maule, Chile earthquake is one of the largest subduction zone earthquakes ever recorded. Up to now numerous co-seismic and some post-seismic slip models have been published based entirely on seismological, geodetic, or tsunami run-up heights, or combinations of these data. Most of these models use a simplified megathrust geometry derived mainly from global earthquake catalogues, and also simplified models of seismic parameters (e.g. shear modulus). By using arrival times for a vast number of aftershocks that have been recorded on a temporary seismic array, we present a new model for the slab geometry based on earthquake locations together with a new 3D seismic velocity model of the region, for both vp and vp/vs. We analyzed 3552 aftershocks that occurred between 18 March and 24 May 2011, recorded by the International Maule Aftershock Dataset (IMAD) seismic network. Event selection from a catalogue of automatically-determined events was based on 20 or more arrival times, from which at least 10 are S-wave observations. In total over 170,000 arrival times (~125,000 and 45,000 P and S wave arrival times respectively) are used for the tomographic reconstructions. Initially, events were relocated in a 2D velocity model based on a previously published model for the southern end of the rupture area (Haberland et al., 2009). Afterwards a staggered inversion scheme is implemented, starting with a 2D inversion followed by a coarse 3D and a subsequent fine 3D inversion. Based on our preliminary inversions we conclude that aftershock seismicity is mainly concentrated between 20 and 35 km depth along the subduction interface. A second band of seismicity between 40 and 50 km depth is also observed. Low seismic velocities and an increased vp/vs ratio characterize the marine forearc. The obtained velocity model will be discussed.

  12. 3D P-wave velocity structure of the crust and relocation of earthquakes in the Lushan, China, source area

    NASA Astrophysics Data System (ADS)

    Yu, Xiangwei; Wang, Xiaona; Zhang, Wenbo

    2016-04-01

    Many researchers have investigated the Lushan source area with geological and geophysical approaches since the 2013 Lushan, China, earthquake happened. Compared with the previous tomographic studies, we have used a much large data set and an updated tomographic method to determine a small scale three-dimensional P wave velocity structure with spatial resolution less than 5km, which plays the important role for understanding the deep structure and the genetic mechanism beneath the Lushan area. The double difference seismic tomography method is applied to 50,711 absolute first arrival P wave arrival times and 7,294,691 high quality relative P arrival times of 5,285 events of Lushan seismic sequence to simultaneously determine the detailed crustal 3D P wave velocity structure and the hypocenter parameters in the Lushan seismic area. This method takes account of the path anomaly biases explicitly by making full use of valuable information of seismic wave propagation jointly with absolute and relative arrival time data. Our results show that the Lushan mainshock locates at 30.28N, 103.98E, with the depth of 16.38km. The front edge of aftershock in the northeast of mainshock present a spade with a steep dip angle, the aftershocks' extended length is about 12km. In the southwest of Lushan mainshock, the front edge of aftershock in low velocity zone slope gently, the aftershocks' extended length is about 23km. Our high-resolution tomographic model not only displays the general features contained in the previous models, but also reveals some new features. The Tianquan, Shuangshi and Daguan line lies in the transition zone between high velocity anomalies to the southeast and low velocity anomalies to the northwest at the ground surface. An obvious high-velocity anomaly is visible in Daxing area. With the depth increasing, Baoxing high velocity anomaly extends to Lingguan, while the southeast of the Tianquan, Shuangshi and Daguan line still shows low velocity. The high-velocity

  13. A cross-platform solution for light field based 3D telemedicine.

    PubMed

    Wang, Gengkun; Xiang, Wei; Pickering, Mark

    2016-03-01

    Current telehealth services are dominated by conventional 2D video conferencing systems, which are limited in their capabilities in providing a satisfactory communication experience due to the lack of realism. The "immersiveness" provided by 3D technologies has the potential to promote telehealth services to a wider range of applications. However, conventional stereoscopic 3D technologies are deficient in many aspects, including low resolution and the requirement for complicated multi-camera setup and calibration, and special glasses. The advent of light field (LF) photography enables us to record light rays in a single shot and provide glasses-free 3D display with continuous motion parallax in a wide viewing zone, which is ideally suited for 3D telehealth applications. As far as our literature review suggests, there have been no reports of 3D telemedicine systems using LF technology. In this paper, we propose a cross-platform solution for a LF-based 3D telemedicine system. Firstly, a novel system architecture based on LF technology is established, which is able to capture the LF of a patient, and provide an immersive 3D display at the doctor site. For 3D modeling, we further propose an algorithm which is able to convert the captured LF to a 3D model with a high level of detail. For the software implementation on different platforms (i.e., desktop, web-based and mobile phone platforms), a cross-platform solution is proposed. Demo applications have been developed for 2D/3D video conferencing, 3D model display and edit, blood pressure and heart rate monitoring, and patient data viewing functions. The demo software can be extended to multi-discipline telehealth applications, such as tele-dentistry, tele-wound and tele-psychiatry. The proposed 3D telemedicine solution has the potential to revolutionize next-generation telemedicine technologies by providing a high quality immersive tele-consultation experience. PMID:26689324

  14. 3D Coronal Magnetic Field Reconstruction Based on Infrared Polarimetric Observations

    NASA Astrophysics Data System (ADS)

    Kramar, M.; Lin, H.; Tomczyk, S.

    2014-12-01

    Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal phenomena at all scales. A significant progress has been recently achieved here with deployment of the Coronal Multichannel Polarimeter (CoMP) of the High Altitude Observatory (HAO). The instrument provides polarization measurements of Fe xiii 10747 A forbidden line emission. The observed polarization are the result of a line-of-sight (LOS) integration through a nonuniform temperature, density and magnetic field distribution. In order resolve the LOS problem and utilize this type of data, the vector tomography method has been developed for 3D reconstruction of the coronal magnetic field. The 3D electron density and temperature, needed as additional input, have been reconstructed by tomography method based on STEREO/EUVI data. We will present the 3D coronal magnetic field and associated 3D curl B, density, and temperature resulted from these inversions.

  15. Research and implementation of visualization techniques for 3D explosion fields

    NASA Astrophysics Data System (ADS)

    Ning, Jianguo; Xu, Xiangzhao; Ma, Tianbao; Yu, Wen

    2015-12-01

    The visualization of scalar data in 3D explosion fields was devised to solve the problems of the complex physical and the huge data in numerical simulation of explosion mechanics problems. For enhancing the explosion effects and reducing the impacts of image analysis, the adjustment coefficient was added into original Phong illumination model. A variety of accelerated volume rendering algorithm and multithread technique were used to realize the fast rendering and real-time interactive control of 3D explosion fields. Cutaway view was implemented, so arbitrary section of 3D explosion fields can be seen conveniently. Slice can be extracted along three axes of 3D explosion fields, and the value at an arbitrary point on the slice can be gained. The experiment results show that the volume rendering acceleration algorithm can generate high quality images and can increase the speed of image generating, while achieve interactive control quickly.

  16. Development of a State-Wide 3-D Seismic Tomography Velocity Model for California

    NASA Astrophysics Data System (ADS)

    Thurber, C. H.; Lin, G.; Zhang, H.; Hauksson, E.; Shearer, P.; Waldhauser, F.; Hardebeck, J.; Brocher, T.

    2007-12-01

    We report on progress towards the development of a state-wide tomographic model of the P-wave velocity for the crust and uppermost mantle of California. The dataset combines first arrival times from earthquakes and quarry blasts recorded on regional network stations and travel times of first arrivals from explosions and airguns recorded on profile receivers and network stations. The principal active-source datasets are Geysers-San Pablo Bay, Imperial Valley, Livermore, W. Mojave, Gilroy-Coyote Lake, Shasta region, Great Valley, Morro Bay, Mono Craters-Long Valley, PACE, S. Sierras, LARSE 1 and 2, Loma Prieta, BASIX, San Francisco Peninsula and Parkfield. Our beta-version model is coarse (uniform 30 km horizontal and variable vertical gridding) but is able to image the principal features in previous separate regional models for northern and southern California, such as the high-velocity subducting Gorda Plate, upper to middle crustal velocity highs beneath the Sierra Nevada and much of the Coast Ranges, the deep low-velocity basins of the Great Valley, Ventura, and Los Angeles, and a high- velocity body in the lower crust underlying the Great Valley. The new state-wide model has improved areal coverage compared to the previous models, and extends to greater depth due to the data at large epicentral distances. We plan a series of steps to improve the model. We are enlarging and calibrating the active-source dataset as we obtain additional picks from investigators and perform quality control analyses on the existing and new picks. We will also be adding data from more quarry blasts, mainly in northern California, following an identification and calibration procedure similar to Lin et al. (2006). Composite event construction (Lin et al., in press) will be carried out for northern California for use in conventional tomography. A major contribution of the state-wide model is the identification of earthquakes yielding arrival times at both the Northern California Seismic

  17. Investigating particle phase velocity in a 3D spouted bed by a novel fiber high speed photography method

    NASA Astrophysics Data System (ADS)

    Qian, Long; Lu, Yong; Zhong, Wenqi; Chen, Xi; Ren, Bing; Jin, Baosheng

    2013-07-01

    A novel fiber high speed photography method has been developed to measure particle phase velocity in a dense gas-solid flow. The measurement system mainly includes a fiber-optic endoscope, a high speed video camera, a metal halide light source and a powerful computer with large memory. The endoscope which could be inserted into the reactors is used to form motion images of particles within the measurement window illuminated by the metal halide lamp. These images are captured by the high speed video camera and processed through a series of digital image processing algorithms, such as calibration, denoising, enhancement and binarization in order to improve the image quality. Then particles' instantaneous velocity is figured out by tracking each particle in consecutive frames. Particle phase velocity is statistically calculated according to the probability of particle velocity in each frame within a time period. This system has been applied to the investigation of particles fluidization characteristics in a 3D spouted bed. The experimental results indicate that the particle fluidization feature in the region investigated could be roughly classified into three sections by particle phase vertical velocity and the boundary between the first section and the second is the surface where particle phase velocity tends to be 0, which is in good agreement with the results published in other literature.

  18. Lapse-time dependent coda-wave depth sensitivity to local velocity perturbations in 3-D heterogeneous elastic media

    NASA Astrophysics Data System (ADS)

    Obermann, Anne; Planès, Thomas; Hadziioannou, Céline; Campillo, Michel

    2016-07-01

    In the context of seismic monitoring, recent studies made successful use of seismic coda waves to locate medium changes on the horizontal plane. Locating the depth of the changes, however, remains a challenge. In this paper, we use 3-D wavefield simulations to address two problems: firstly, we evaluate the contribution of surface and body wave sensitivity to a change at depth. We introduce a thin layer with a perturbed velocity at different depths and measure the apparent relative velocity changes due to this layer at different times in the coda and for different degrees of heterogeneity of the model. We show that the depth sensitivity can be modelled as a linear combination of body- and surface-wave sensitivity. The lapse-time dependent sensitivity ratio of body waves and surface waves can be used to build 3-D sensitivity kernels for imaging purposes. Secondly, we compare the lapse-time behavior in the presence of a perturbation in horizontal and vertical slabs to address, for instance, the origin of the velocity changes detected after large earthquakes.

  19. 3D strain measurement in electronic devices using through-focal annular dark-field imaging.

    PubMed

    Kim, Suhyun; Jung, Younheum; Lee, Sungho; Jung Kim, Joong; Byun, Gwangseon; Lee, Sunyoung; Lee, Haebum

    2014-11-01

    Spherical aberration correction in high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) allows us to form an electron probe with reduced depth of field. Using through-focal HAADF imaging, we experimentally demonstrated 3D strain measurement in a strained-channel transistor. The strain field distribution in the channel region was obtained by scanning an electron beam over a plan-view specimen. Furthermore, the decrease in the strain fields toward the silicon substrate was revealed at different focal planes with a 5-nm focal step. These results demonstrate that it is possible to reconstruct the 3D strain field in electronic devices. PMID:24859824

  20. A 360-degree floating 3D display based on light field regeneration.

    PubMed

    Xia, Xinxing; Liu, Xu; Li, Haifeng; Zheng, Zhenrong; Wang, Han; Peng, Yifan; Shen, Weidong

    2013-05-01

    Using light field reconstruction technique, we can display a floating 3D scene in the air, which is 360-degree surrounding viewable with correct occlusion effect. A high-frame-rate color projector and flat light field scanning screen are used in the system to create the light field of real 3D scene in the air above the spinning screen. The principle and display performance of this approach are investigated in this paper. The image synthesis method for all the surrounding viewpoints is analyzed, and the 3D spatial resolution and angular resolution of the common display zone are employed to evaluate display performance. The prototype is achieved and the real 3D color animation image has been presented vividly. The experimental results verified the representability of this method. PMID:23669981

  1. Full-field drift Hamiltonian particle orbits in 3D geometry

    NASA Astrophysics Data System (ADS)

    Cooper, W. A.; Graves, J. P.; Brunner, S.; Isaev, M. Yu

    2011-02-01

    A Hamiltonian/Lagrangian theory to describe guiding centre orbit drift motion which is canonical in the Boozer coordinate frame has been extended to include full electromagnetic perturbed fields in anisotropic pressure 3D equilibria with nested magnetic flux surfaces. A redefinition of the guiding centre velocity to eliminate the motion due to finite equilibrium radial magnetic fields and the choice of a gauge condition that sets the radial component of the electromagnetic vector potential to zero are invoked to guarantee that the Boozer angular coordinates retain the canonical structure. The canonical momenta are identified and the guiding centre particle radial drift motion and parallel gyroradius evolution are derived. The particle coordinate position is linearly modified by wave-particle interactions. All the nonlinear wave-wave interactions appear explicitly only in the evolution of the parallel gyroradius. The radial variation of the electrostatic potential is related to the binormal component of the displacement vector for MHD-type perturbations. The electromagnetic vector potential projections can then be determined from the electrostatic potential and the radial component of the MHD displacement vector.

  2. Study on 3-D velocity structure of crust and upper mantle in Sichuan-yunnan region, China

    USGS Publications Warehouse

    Wang, C.; Mooney, W.D.; Wang, X.; Wu, J.; Lou, H.; Wang, F.

    2002-01-01

    Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is determined, incorporating with previous deep geophysical data. In the upper crust, a positive anomaly velocity zone exists in the Sichuan basin, whereas a negative anomaly velocity zone exists in the western Sichuan plateau. The boundary between the positive and negative anomaly zones is the Longmenshan fault zone. The images of lower crust and upper mantle in the Longmenshan fault, Xianshuihe fault, Honghe fault and others appear the characteristic of tectonic boundary, indicating that the faults litely penetrate the Moho discontinuity. The negative velocity anomalies at the depth of 50 km in the Tengchong volcanic area and the Panxi tectonic zone appear to be associated with the temperature and composition variations in the upper mantle. The overall features of the crustal and the upper mantle structures in the Sichuan-Yunnan region are the lower average velocity in both crust and uppermost mantle, the large crustal thickness variations, and the existence of high conductivity layer in the crust or/and upper mantle, and higher geothermal value. All these features are closely related to the collision between the Indian and the Asian plates. The crustal velocity in the Sichuan-Yunnan rhombic block generally shows normal.value or positive anomaly, while the negative anomaly exists in the area along the large strike-slip faults as the block boundary. It is conducive to the crustal block side-pressing out along the faults. In the major seismic zones, the seismicity is relative to the negative anomaly velocity. Most strong earthquakes occurred in the upper-mid crust with positive anomaly or normal velocity, where the negative anomaly zone generally exists below.

  3. On the location of microseismic sources in instable rock slope areas: heterogeneous vs. homogenous 3D velocity models

    NASA Astrophysics Data System (ADS)

    Coviello, Velio; Manconi, Andrea; Occhiena, Cristina; Arattano, Massimo; Scavia, Claudio

    2013-04-01

    Rock-falls are one of the most common and hazardous phenomena occurring in mountainous areas. The formation of cracks in rocks is often accompanied by a sudden release of energy, which propagates in form of elastic waves and can be detected by a suitable transducer array. Therefore, geophones are among the most effective monitoring devices to investigate eventual precursors of rock-fall phenomena. However, the identification of an efficient procedure to forecast rock-fall occurrence in space and time is still an open challenge. In this study, we aim at developing an efficient procedure to locate microseismic sources relevant to cracking mechanisms, and thus gather indications on eventual precursors of rock-fall phenomena. Common seismic location tools usually implement homogeneous or multilayered velocity models but, in case of high slope gradients and heavily fractured rock masses, these simplifications may lead to errors on the correct estimation of the source location. Thus, we analyzed how the consideration of 3D material properties on the propagation medium may influence the location. In the framework of the Alcotra 2007-2013 Project MASSA (Medium And Small Size rock-fall hazard Assessment), a monitoring system composed by 8 triaxial geophones was installed in 2010 at the J.A. Carrel hut (3829 m a.s.l., Matterhorn, NW Italian Alps) and during the first year of operation the network recorded more than 600 natural events that exceeded a fixed threshold [1]. Despite the harsh environmental conditions of the study area, eighteen points distributed as uniformly as possible in space were selected for hammering. The artificial source dataset of known coordinates was used to constrain a 3D heterogeneous velocity model through a Simultaneous Iterative Reconstructive Technique. In order to mitigate the intrinsic uncertainties of the inversion procedure, bootstrapping was performed to extend the dataset and a statistical analysis was issued to improve the model

  4. Using Ambient Noise Data from the ALBACORE OBS Array to Determine a 3D Seismic Velocity Model Offshore Southern California

    NASA Astrophysics Data System (ADS)

    Kohler, M. D.; Bowden, D. C.; Tsai, V. C.; Weeraratne, D. S.

    2014-12-01

    The Pacific-North America plate boundary in Southern California extends far west of the coastline, and a 12-month ocean bottom seismometer (OBS) array spanned the western side of the plate boundary in order to image seismic velocities in the lithosphere. Velocities are modeled through stacked cross correlations of ambient noise data. The offshore data come primarily from the OBS array that collected 12 months of continuous data during 2010-2011, combined with Southern California Seismic Network (SCSN) station data. The cross correlations were stacked for noise correlation functions and examined using standard time- and frequency-domain methods to determine phase velocity and group velocity dispersion curves. Signals between the vertical-component OBS and co-located horizontal-component OBS observations associated with tilt noise, and pressure gauge observations associated with infragravity waves, were examined to further improve signals. The non-elastic noise was estimated by calculating the transfer functions between the vertical-to-horizontal and vertical-to-pressure components, and subtracting the coherent signal between the two from the vertical-component time series. We find that these effects are small in our dataset. We are simultaneously inverting all measureable dispersion curves to solve for 3D crustal velocity structure. Shear-wave velocities comprise the direct solution, and Vp/Vs ratios are constrained as much as the data allow. Calculations on data from 780 OBS-OBS, SCSN-SCSN, and OBS-SCSN pairs filtered around multiple narrow bands between 5 and 50 s show clear propagating waves traveling at group velocities between 1.2 and 3.5 km/s. The longer-term outcome of this work will comprise a 3D crustal and uppermost mantle velocity model with areal coverage not attainable before the deployment of the ocean bottom seismometers. The results define the transition in three dimensions from continental lithospheric structure in the near-shore region to oceanic

  5. 3D Velocity and Hypocentre Distribution About a Cone-Volcano: Mt Taranaki, New Zealand

    NASA Astrophysics Data System (ADS)

    Sherburn, S.; White, R.

    2003-12-01

    Mt Taranaki is a 2518 m andesite cone-volcano (last eruption AD1755) within an oil-bearing sedimentary basin approximately 50 km west of the deepest part of the Benioff zone beneath the North Island of New Zealand. It is the most recent of a series of volcanoes that have erupted in the Taranaki region in the last 1.7 million years. Although a permanent six-station seismic network monitors Mt Taranaki for signs of unrest, little is known of the structure at the depths earthquakes occur and magma maybe stored. This information is vital for interpreting precursors to any future eruption. For nine months in 2001-2002, a temporary network of 75 three-component, broadband (0.03 - 50 Hz) seismographs (area c. 100 km by 100 km) was used to collect data to image crustal structure and accurately locate earthquakes in the Taranaki region. Three hundred and eighty-nine earthquakes were located using more than 15,000 phase picks (55% P and 45% S). A joint inversion for 1D Vp, Vs and hypocentres was undertaken using Velest followed by a 3D inversion for Vp, Vp/Vs ratio and hypocentres using Simul2000. The base of the seismogenic zone increases gradually from a depth of 20 km immediately west of Mt Taranaki to 35 km deep 100 km to the east, corresponding to a previously observed increase in crustal thickness. The area close to Mt Taranaki is anomalous in that there are few earthquakes and all are shallower than 10 km. Within the upper 5-10 km of the crust Vp is closely related to surface geology, being high beneath Mt Taranaki, low beneath the surrounding sedimentary basin, and very high to the east of the basin. We present the Vp and Vp/Vs structure and hypocentre distribution of the Taranaki region and discuss features that can be attributed to volcanism at Mt Taranaki and older volcanic centres.

  6. A Robust Method to Detect Zero Velocity for Improved 3D Personal Navigation Using Inertial Sensors

    PubMed Central

    Xu, Zhengyi; Wei, Jianming; Zhang, Bo; Yang, Weijun

    2015-01-01

    This paper proposes a robust zero velocity (ZV) detector algorithm to accurately calculate stationary periods in a gait cycle. The proposed algorithm adopts an effective gait cycle segmentation method and introduces a Bayesian network (BN) model based on the measurements of inertial sensors and kinesiology knowledge to infer the ZV period. During the detected ZV period, an Extended Kalman Filter (EKF) is used to estimate the error states and calibrate the position error. The experiments reveal that the removal rate of ZV false detections by the proposed method increases 80% compared with traditional method at high walking speed. Furthermore, based on the detected ZV, the Personal Inertial Navigation System (PINS) algorithm aided by EKF performs better, especially in the altitude aspect. PMID:25831086

  7. A robust method to detect zero velocity for improved 3D personal navigation using inertial sensors.

    PubMed

    Xu, Zhengyi; Wei, Jianming; Zhang, Bo; Yang, Weijun

    2015-01-01

    This paper proposes a robust zero velocity (ZV) detector algorithm to accurately calculate stationary periods in a gait cycle. The proposed algorithm adopts an effective gait cycle segmentation method and introduces a Bayesian network (BN) model based on the measurements of inertial sensors and kinesiology knowledge to infer the ZV period. During the detected ZV period, an Extended Kalman Filter (EKF) is used to estimate the error states and calibrate the position error. The experiments reveal that the removal rate of ZV false detections by the proposed method increases 80% compared with traditional method at high walking speed. Furthermore, based on the detected ZV, the Personal Inertial Navigation System (PINS) algorithm aided by EKF performs better, especially in the altitude aspect. PMID:25831086

  8. Quantitative 3D electromagnetic field determination of 1D nanostructures from single projection.

    PubMed

    Phatak, C; de Knoop, L; Houdellier, F; Gatel, C; Hÿtch, M J; Masseboeuf, A

    2016-05-01

    One-dimensional (1D) nanostructures have been regarded as the most promising building blocks for nanoelectronics and nanocomposite material systems as well as for alternative energy applications. Although they result in confinement of a material, their properties and interactions with other nanostructures are still very much three-dimensional (3D) in nature. In this work, we present a novel method for quantitative determination of the 3D electromagnetic fields in and around 1D nanostructures using a single electron wave phase image, thereby eliminating the cumbersome acquisition of tomographic data. Using symmetry arguments, we have reconstructed the 3D magnetic field of a nickel nanowire as well as the 3D electric field around a carbon nanotube field emitter, from one single projection. The accuracy of quantitative values determined here is shown to be a better fit to the physics at play than the value obtained by conventional analysis. Moreover the 3D reconstructions can then directly be visualized and used in the design of functional 3D architectures built using 1D nanostructures. PMID:26998702

  9. Generation of nearly 3D-unpolarized evanescent optical near fields using total internal reflection.

    PubMed

    Hassinen, Timo; Popov, Sergei; Friberg, Ari T; Setälä, Tero

    2016-07-01

    We analyze the time-domain partial polarization of optical fields composed of two evanescent waves created in total internal reflection by random electromagnetic beams with orthogonal planes of incidence. We show that such a two-beam configuration enables to generate nearly unpolarized, genuine three-component (3D) near fields. This result complements earlier studies on spectral polarization, which state that at least three symmetrically propagating beams are required to produce a 3D-unpolarized near field. The degree of polarization of the near field can be controlled by adjusting the polarization states and mutual correlation of the incident beams. PMID:27367071

  10. 3-D velocity structure around tehri region of the garhwal lesser himalaya: constraints on geometry of the underthrusting indian plate

    NASA Astrophysics Data System (ADS)

    Kanaujia, Jyotima; Kumar, Ashwani; Gupta, S. C.

    2016-02-01

    We investigate the upper crustal velocity structure beneath the Tehri region of the Garhwal Himalaya. The investigated region is situated within the 700-km-long central seismic gap of the Himalaya that has experienced three gap-filling earthquakes since 1991 including the recent 2015 Nepal earthquake (Mw 7.8). The local tomographic inversion is based on a dataset of 1365 events collected from January 2008 to December 2012 by a 12-station local network that covers an area of about 100 × 80 km around Tehri Dam. We perform a simultaneous inversion for P- and S-wave velocity anomalies. Tomograms are interpreted in the backdrop of the regional geological and tectonic framework of the region. The spatial distribution of relocated events from the 3- D velocity model has shed new light on the pattern of seismicity in the vicinity of the Main Central thrust (MCT), and has elucidated the structure of the underthrusting Indian plate. Our model exhibits a significant negative velocity anomaly up to ˜5 per cent beneath the central part of the Garhwal Inner Lesser Himalaya, and a P-wave low velocity anomaly near the Chamoli region. The seismicity zone around the Chamoli region may be attributed to the presence of fluid filled rocks. Furthermore, an area with˜3-4 per cent positive velocity anomaly is delineated to the northwest of the Uttarkashi thrust in the vicinity of the MCT. Significant findings of the study include: a flat-ramp-flat type sub-surface geometry of the underthrusting Indian plate below the Garhwal Himalaya, high velocity images representing the trend and configuration of Delhi-Haridwar-ridge below the Sub Himalaya and Lesser Himalaya, and a seismically active zone representing geometrical asperity on the basement thrust in the vicinity of the MCT.

  11. Numerical Modeling of seismic wave propagation on Etna Volcano (Italy): Construction of 3D realistic velocity structures

    NASA Astrophysics Data System (ADS)

    Trovato, Claudio; Aochi, Hideo; De Martin, Florent

    2014-05-01

    Understanding the source mechanism of long-period (LP) seismic signals on volcanoes is an important key point in volcanology and for the hazard forecasting. In the last decades, moment tensor inversions have led to various descriptions of the kinematic source mechanism. These inversions suppose a relatively simple structure of the medium. However, the seismic wave propagation in a realistic 3-D volcano model should be taken into account for understanding the complicated physical processes of magma and gas behaviors at depth. We are studying Etna volcano, Italy, to understand the volcanic processes during different stages of activity. We adopt a spectral element method (SEM), a code EFISPEC3D (De Martin, BSSA, 2011), which shows a good accuracy and numerical stability in the simulations of seismic wave propagation. First we construct the geometrical model. We use a digital elevation model (DEM) to generate finite element meshes with a spacing of 50 m on the ground surface. We aim to calculate the ground motions until 3 Hz for the shallowest layer with Vs = ~500 m/s. The minimal size of the hexahedral elements is required to be around 100 m, with a total number of elements n = ~2 10 ^ 6 for the whole model. We compare different velocity structure configurations. We start with a homogeneous medium and add complexities taking in account the shallow low velocity structure. We also introduce a velocity gradient towards depth. Simulations performed in the homogeneous medium turn in approximately 20 hours for calculations parallelized on 16 CPUs. Complex velocity models should take approximately the same time of computation. We then try to simulate the ground motion from the LP sources (0.1-1.5 Hz) obtained by the inversion for the Etna volcano in 2008 (De Barros, GRL, 2009 and De Barros, JGR, 2011). Some vertical and horizontal structures can be added to reproduce injected dikes or sills respectively.

  12. Three-Dimensional (3-D) Reconstructions of EISCAT IPS Velocity Data in the Declining Phase of Solar Cycle 23

    NASA Astrophysics Data System (ADS)

    Bisi, M. M.; Jackson, B. V.; Breen, A. R.; Dorrian, G. D.; Fallows, R. A.; Clover, J. M.; Hick, P. P.

    2010-08-01

    The European Incoherent SCATter (EISCAT) radar has been used for remote-sensing observations of interplanetary scintillation (IPS) for a quarter of a century. During the April/May 2007 observing campaign, a large number of observations of IPS using EISCAT took place to give a reasonable spatial and temporal coverage of solar wind velocity structure throughout this time during the declining phase of Solar Cycle 23. Many co-rotating and transient features were observed during this period. Using the University of California, San Diego three-dimensional (3-D) time-dependent computer assisted tomography (C.A.T.) solar-wind reconstruction analysis, we show the velocity structure of the inner heliosphere in three dimensions throughout the time interval of 20 April through 20 May 2007. We also compare to white-light remote-sensing observations of an interplanetary coronal mass ejection (ICME) seen by the STEREO Ahead spacecraft inner Heliospheric Imager on 16 May 2007, as well as to in-situ solar-wind measurements taken with near-Earth spacebourne instrumentation throughout this interval. The reconstructions show clear co-rotating regions during this period, and the time-series extraction at spacecraft locations compares well with measurements made by the STEREO, Wind, and ACE spacecraft. This is the first time such clear structures have been revealed using this 3-D technique with EISCAT IPS data as input.

  13. Fully automated measurement of field-dependent AMS using MFK1-FA Kappabridge equipped with 3D rotator

    NASA Astrophysics Data System (ADS)

    Chadima, Martin; Studynka, Jan

    2013-04-01

    Low-field magnetic susceptibility of paramagnetic and diamagnetic minerals is field-independent by definition being also field-independent in pure magnetite. On the other hand, in pyrrhotite, hematite and high-Ti titanomagnetite it may be clearly field-dependent. Consequently, the field-dependent AMS enables the magnetic fabric of the latter group of minerals to be separated from the whole-rock AMS. The methods for the determination of the field-dependent AMS consist of separate measurements of each specimen in several fields within the Rayleigh Law range and subsequent processing in which the field-independent and field-dependent AMS components are calculated. The disadvantage of this technique is that each specimen must be measured several times, which is relatively laborious and time consuming. Recently, a new 3D rotator was developed for the MFK1-FA Kappabridge, which rotates the specimen simultaneously about two axes with different velocities. The measurement is fully automated in such a way that, once the specimen is inserted into the rotator, it requires no additional manipulation to measure the full AMS tensor. Consequently, the 3D rotator enables to measure the AMS tensors in the pre-set field intensities without any operator interference. Whole procedure is controlled by newly developed Safyr5 software; once the measurements are finished, the acquired data are immediately processed and can be visualized in a standard way.

  14. Transient 3D elastodynamic field in an embedded multilayered anisotropic plate.

    PubMed

    Mora, Pierric; Ducasse, Eric; Deschamps, Marc

    2016-07-01

    The aim of this paper is to study the ultrasonic response to a transient source that radiates ultrasonic waves in a 3D embedded multilayered anisotropic and dissipative plate. The source can be inside the plate or outside, in a fluid loading the plate for example. In the context of Non-Destructive Testing applied to composite materials, our goal is to create a robust algorithm to calculate ultrasonic field, irrespective of the source and receiver positions. The principle of the method described in this paper is well-established. This method is based on time analysis using the Laplace transform. In the present work, it has been customized for computing ultrasonic source interactions with multilayered dissipative anisotropic plates. The fields are transformed in the 2D Fourier wave-vector domain for the space variables related to the plate surface, and they are expressed in the partial-wave basis. Surprisingly, this method has been very little used in the ultrasonic community, while it is a useful tool which complements the much used technique based on generalized Lamb wave decomposition. By avoiding mode analysis - which can be problematic in some cases - exact numerical calculations (i.e., approximations by truncating infinite series that may be poorly convergent are not needed) can be made in a relatively short time for immersed plates and viscoelastic layers. Even for 3D cases, numerical costs are relatively low. Special attention is given to separate up- and down-going waves, which is a simple matter when using the Laplace transform. Numerical results show the effectiveness of this method. Three examples are presented here to investigate the quality of the model and the robustness of the algorithm: first, a comparison of experiment and simulation for a monolayer carbon-epoxy plate, where the diffracted field is due to a source located on the first free surface of the sample, for both dissipative and non-dissipative cases; second, the basic configuration of an

  15. 3D model of small-scale density cavities in the auroral magnetosphere with field-aligned current

    NASA Astrophysics Data System (ADS)

    Bespalov, P. A.; Misonova, V. G.; Savina, O. N.

    2016-09-01

    We propose a 3D model of small-scale density cavities stimulated by an auroral field-aligned current and an oscillating field-aligned current of kinetic Alfvén waves. It is shown that when the field-aligned current increases so that the electron drift velocity exceeds a value of the order of the electron thermal velocity, the plasma becomes unstable to the formation of cavities with low density and strong electric field. The condition of instability is associated with the value of the background magnetic field. In the case of a relatively weak magnetic field (where the electron gyro-radius is greater than the ion acoustic wavelength), the current instability can lead to the formation of one-dimensional cavities along the magnetic field. In the case of a stronger magnetic field (where the ion acoustic wavelength is greater than the electron gyro-radius, but still is less than the ion gyro-radius), the instability can lead to the formation of 3D density cavities. In this case, the spatial scales of the cavity, both along and across the background magnetic field, can be comparable, and at the earlier stage of the cavity formation they are of the order of the ion acoustic wavelength. Rarefactions of the cavity density are accompanied by an increase in the electric field and are limited by the pressure of bipolar electric fields that occur within them. The estimates of typical density cavity characteristics and the results of numerical solutions agree with known experimental data: small-scale structures with a sufficiently strong electric field are observed in the auroral regions with strong field-aligned current.

  16. 3D Anisotropic Velocity Tomography of a Water Saturated Rock under True-Triaxial Stress in the Laboratory

    NASA Astrophysics Data System (ADS)

    Ghofrani Tabari, M.; Goodfellow, S. D.; Nasseri, M. B.; Young, R.

    2013-12-01

    A cubic specimen of water saturated Fontainebleau Sandstone is tested in the laboratory under true-triaxial loading where three different principal stresses are applied under drained conditions. Due to the loading arrangement, closure and opening of the pre-existing cracks in the rock, as well as creation and growth of the aligned cracks cause elliptical anisotropy and distributed heterogeneities. A Geophysical Imaging Cell equipped with an Acoustic Emission monitoring system is employed to image velocity structure of the sample during the experiment through repeated transducer to transducer non-destructive ultrasonic surveys. Apparent P-wave velocities along the rock body are calculated in different directions and shown in stereonet plots which demonstrate an overall anisotropy of the sample. The apparent velocities in the main three orthogonal cubic directions are used as raw data for building a mean spatial distribution model of anisotropy ratios. This approach is based on the concept of semi-principal axes in an elliptical anisotropic model and appointing two ratios between the three orthogonal velocities in each of the cubic grid cells. The spatial distribution model of anisotropy ratios are used to calculate the anisotropic ray-path segment matrix elements (Gij). These contain segment lengths of the ith ray in the jth cell in three dimensions where, length of each ray in each cell is computed for one principal direction based on the dip and strike of the ray and these lengths differ from the ones in an isotropic G Matrix. 3D strain of the squeezed rock and the consequent geometrical deformation is also included in the ray-path segment matrix. A Singular Value Decomposition (SVD) method is used for inversion from the data space of apparent velocities to the model space of P-wave propagation velocities in the three principal directions. Finally, spatial variation and temporal evolution of induced damages in the rock, representing uniformly distributed or

  17. 3D airflow dynamics over transverse ridges Mpekweni, South Africa: implications for dune field migration behaviour

    NASA Astrophysics Data System (ADS)

    Jackson, Derek; Cooper, Andrew; Green, Andrew; Beyers, Meiring; Wiles, Errol; Benallack, Keegan

    2016-04-01

    Un-vegetated dune fields provide excellent opportunities to examine airflow dynamics over various types and scales of dune landforms. The three dimensional surface over which lower boundary layers travel, help adjust surface airflow and consequently the aeolian response of the dunes themselves. The use of computational fluid dynamic (CFD) modelling in recent studies now enables investigation of the 3D behaviour of airflow over complex terrain, providing new insights into heterogeneous surface flow and aeolian response of dune surfaces on a large (dunefield) scale. Using a largely un-vegetated coastal dune field site at Mpekweni, Eastern Cape, South Africa, a detailed (0.1m gridded) terrestrial laser scanning survey was conducted to create a high resolution topographical surface. Using local wind flow measurements and local met station records as input, CFD modelling was performed for a number of scenarios involving variable direction and magnitude to examine surface flow patterns across multiple dune forms. Near surface acceleration, expansion and separation of airflow inducing convergence and divergence (steering) of flow velocity streamlines are investigated. Flow acceleration over dune crests/brink lines is a key parameter in driving dune migration and slip face dynamics. Dune aspect ratio (height to length) is also important in determining the degree of crestal flow acceleration, with an increase in flow associated with increasing aspect ratios. Variations in dune height appear to be the most important parameter in driving general flow acceleration. The results from the study provide new insights into dune migration behaviour at this site as well as surface flow behaviour across multiple dune configurations and length scales within un-vegetated dune fields.

  18. Slip versus Field-Line Mapping in Describing 3D Reconnection of Coronal Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Titov, V. S.; Mikic, Z.; Torok, T.; Downs, C.; Lionello, R.; Linker, J.

    2015-12-01

    We demonstrate two techniques for describing the structure of the coronal magnetic field and its evolution due to reconnection in numerical 3D simulations of the solar corona and CMEs. These techniques employ two types of mapping of the boundary of the computational domain on itself. One of them is defined at a given time moment via connections of the magnetic field lines to their opposite endpoints. The other mapping, called slip mapping, relates field line endpoints at two different time moments and allows one to identify the slippage of plasma elements due to resistivity across field lines for a given time interval (Titov et al. 2009). The distortion of each of these mappings can be measured by using the so-called squashing factor Q (Titov 2007). The high-Q layers computed for the first and second mappings define, respectively, (quasi-)separatrix surfaces and reconnection fronts in evolving magnetic configurations. Analyzing these structural features, we are able to reveal topologically different domains and reconnected flux systems in the configurations, in particular, open, closed and disconnected magnetic flux tubes, as well as quantify the related magnetic flux transfer. Comparison with observations makes it possible also to relate these features to observed morphological elements such as flare loops and ribbons, and EUV dimmings. We illustrate these general techniques by applying them to particular data-driven MHD simulations. *Research supported by NASA's HSR and LWS Programs, and NSF/SHINE and NSF/FESD.

  19. 3-D velocity heterogeneity in earthquake swarm area of NW Bohemia/Vogtland (German-Czech border region)

    NASA Astrophysics Data System (ADS)

    Mousavi, Sima; Bauer, Klaus; Korn, Michael

    2014-05-01

    3-D Vp and Vp/Vs structure of the geodynamically active NW Bohemia/Vogtland area, located at the border region between Germany and Czech republic, has been determined from local earthquake tomography using 543 earthquakes which have been recorded during 2000 to 2010. This region is known for the occurrence of earthquake swarms that are supposed to be triggered by fluid upwelling in the crust, although fluid behaviour and migration paths in the subsurface of NW Bohemia is still poorly known. The events used in this study were selected based on a minimum 12 P and S phase observations and an azimuthal gap less than 160º. This data set is employed to derive a minimum 1-D velocity model and to relocate the hypocenters. The minimum 1-D velocity model is then used as an initial model in non-linear inversion to derive 3-D P-velocity and Vp/Vs ratio. Using synthetic tests, it can be shown that a high resolution is obtained in the central part of the studied region with the given source and receiver configuration. Two branches of high Vp/Vs ratio anomalies have been detected above the swarm quakes' focal zone. These anomalies support the existence of two main fluid passages toward Bad Brambach and Bublak moffette. Another interesting result is a high Vp/Vs line-like anomaly along Mariánské Lázně fault where most of the swarm quakes occur, which could be due to a fluid saturated area around the cracked zone of the fault plain. Hypocenters in the swarm region are located in a low Vp and Vp/Vs anomaly. The correlation between the detected Vp and Vp/Vs anomalies and the location of earthquake swarm suggests a model in which CO2 as part of magmatic fluids exist in a vast area beneath NW Bohemia and frequently migrate up to the surface.

  20. Models Ion Trajectories in 2D and 3D Electrostatic and Magnetic Fields

    2000-02-21

    SIMION3D7.0REV is a C based ion optics simulation program that can model complex problems using Laplace equation solutions for potential fields. The program uses an ion optics workbench that can hold up to 200 2D and/or 3D electrostatic/magnetic potential arrays. Arrays can have up to 50,000,000 points. SIMION3D7.0''s 32 bit virtual Graphics User Interface provides a highly interactive advanced user environment. All potential arrays are visualized as 3D objects that the user can cut awaymore » to inspect ion trajectories and potential energy surfaces. User programs allow the user to customize the program for specific simulations. A geometry file option supports the definition of highly complex array geometry. Algorithm modifications have improved this version''s computational speed and accuracy.« less

  1. Models Ion Trajectories in 2D and 3D Electrostatic and Magnetic Fields

    SciTech Connect

    Dahl, David

    2000-02-21

    SIMION3D7.0REV is a C based ion optics simulation program that can model complex problems using Laplace equation solutions for potential fields. The program uses an ion optics workbench that can hold up to 200 2D and/or 3D electrostatic/magnetic potential arrays. Arrays can have up to 50,000,000 points. SIMION3D7.0''s 32 bit virtual Graphics User Interface provides a highly interactive advanced user environment. All potential arrays are visualized as 3D objects that the user can cut away to inspect ion trajectories and potential energy surfaces. User programs allow the user to customize the program for specific simulations. A geometry file option supports the definition of highly complex array geometry. Algorithm modifications have improved this version''s computational speed and accuracy.

  2. A 3D Seismic Velocity Model Offshore Southern California from Ambient Noise Tomography of the ALBACORE OBS Array

    NASA Astrophysics Data System (ADS)

    Kohler, M. D.; Bowden, D. C.; Tsai, V. C.; Weeraratne, D. S.

    2015-12-01

    The Pacific-North America plate boundary in Southern California extends far west of the coastline, and a 12-month ocean bottom seismometer (OBS) array spanned the western side of the plate boundary to image lithospheric seismic velocities. Velocities are modeled through stacked cross correlations of ambient noise data. Twelve months of continuous data were used from 22 OBS stations and ~30 coastal and island Southern California Seismic Network stations. Particular attention has been paid to improving signal-to-noise ratios in the noise correlations with OBS stations by removing the effects of instrument tilt and infragravity waves. Different applications of preprocessing techniques allow us to distinguish the fundamental and first higher order Rayleigh modes, especially in deep water OBS pairs where the water layer dominates crustal sensitivity of the fundamental mode. Standard time domain and frequency domain methods are used to examine surface wave dispersion curves for group and phase velocities between 5 and 50 second periods, and these are inverted for 3D velocity structure. The results define the transition in three dimensions from continental lithospheric structure in the near-shore region to oceanic structure west of the continental borderland. While the most prominent features of the model relate to thinning of the crust west of the Patton Escarpment, other notable anomalies are present north-to-south throughout the continental borderland and along the coast from the Los Angeles Basin to the Peninsular Ranges. The velocity model will help describe the region's tectonic history, as well as provide new constraints for determination of earthquake relocations and rupture styles.

  3. Direct Detection of the Helical Magnetic Field Geometry from 3D Reconstruction of Prominence Knot Trajectories

    NASA Astrophysics Data System (ADS)

    Zapiór, Maciej; Martínez-Gómez, David

    2016-02-01

    Based on the data collected by the Vacuum Tower Telescope located in the Teide Observatory in the Canary Islands, we analyzed the three-dimensional (3D) motion of so-called knots in a solar prominence of 2014 June 9. Trajectories of seven knots were reconstructed, giving information of the 3D geometry of the magnetic field. Helical motion was detected. From the equipartition principle, we estimated the lower limit of the magnetic field in the prominence to ≈1-3 G and from the Ampère’s law the lower limit of the electric current to ≈1.2 × 109 A.

  4. On Animating 2D Velocity Fields

    NASA Technical Reports Server (NTRS)

    Kao, David; Pang, Alex; Yan, Jerry (Technical Monitor)

    2001-01-01

    A velocity field, even one that represents a steady state flow, implies a dynamical system. Animated velocity fields is an important tool in understanding such complex phenomena. This paper looks at a number of techniques that animate velocity fields and propose two new alternatives. These are texture advection and streamline cycling. The common theme among these techniques is the use of advection on some texture to generate a realistic animation of the velocity field. Texture synthesis and selection for these methods are presented. Strengths and weaknesses of the techniques are also discussed in conjunctions with several examples.

  5. On Animating 2D Velocity Fields

    NASA Technical Reports Server (NTRS)

    Kao, David; Pang, Alex

    2000-01-01

    A velocity field. even one that represents a steady state flow implies a dynamical system. Animated velocity fields is an important tool in understanding such complex phenomena. This paper looks at a number of techniques that animate velocity fields and propose two new alternatives, These are texture advection and streamline cycling. The common theme among these techniques is the use of advection on some texture to generate a realistic animation of the velocity field. Texture synthesis and selection for these methods are presented. Strengths and weaknesses of the techniques are also discussed in conjunction with several examples.

  6. Synthesis of 3D Model of a Magnetic Field-Influenced Body from a Single Image

    NASA Technical Reports Server (NTRS)

    Wang, Cuilan; Newman, Timothy; Gallagher, Dennis

    2006-01-01

    A method for recovery of a 3D model of a cloud-like structure that is in motion and deforming but approximately governed by magnetic field properties is described. The method allows recovery of the model from a single intensity image in which the structure's silhouette can be observed. The method exploits envelope theory and a magnetic field model. Given one intensity image and the segmented silhouette in the image, the method proceeds without human intervention to produce the 3D model. In addition to allowing 3D model synthesis, the method's capability to yield a very compact description offers further utility. Application of the method to several real-world images is demonstrated.

  7. Identification of source velocities on 3D structures in non-anechoic environments: Theoretical background and experimental validation of the inverse patch transfer functions method

    NASA Astrophysics Data System (ADS)

    Aucejo, M.; Totaro, N.; Guyader, J.-L.

    2010-08-01

    In noise control, identification of the source velocity field remains a major problem open to investigation. Consequently, methods such as nearfield acoustical holography (NAH), principal source projection, the inverse frequency response function and hybrid NAH have been developed. However, these methods require free field conditions that are often difficult to achieve in practice. This article presents an alternative method known as inverse patch transfer functions, designed to identify source velocities and developed in the framework of the European SILENCE project. This method is based on the definition of a virtual cavity, the double measurement of the pressure and particle velocity fields on the aperture surfaces of this volume, divided into elementary areas called patches and the inversion of impedances matrices, numerically computed from a modal basis obtained by FEM. Theoretically, the method is applicable to sources with complex 3D geometries and measurements can be carried out in a non-anechoic environment even in the presence of other stationary sources outside the virtual cavity. In the present paper, the theoretical background of the iPTF method is described and the results (numerical and experimental) for a source with simple geometry (two baffled pistons driven in antiphase) are presented and discussed.

  8. Qualitative and quantitative comparative analyses of 3D lidar landslide displacement field measurements

    NASA Astrophysics Data System (ADS)

    Haugen, Benjamin D.

    Landslide ground surface displacements vary at all spatial scales and are an essential component of kinematic and hazards analyses. Unfortunately, survey-based displacement measurements require personnel to enter unsafe terrain and have limited spatial resolution. And while recent advancements in LiDAR technology provide the ability remotely measure 3D landslide displacements at high spatial resolution, no single method is widely accepted. A series of qualitative metrics for comparing 3D landslide displacement field measurement methods were developed. The metrics were then applied to nine existing LiDAR techniques, and the top-ranking methods --Iterative Closest Point (ICP) matching and 3D Particle Image Velocimetry (3DPIV) -- were quantitatively compared using synthetic displacement and control survey data from a slow-moving translational landslide in north-central Colorado. 3DPIV was shown to be the most accurate and reliable point cloud-based 3D landslide displacement field measurement method, and the viability of LiDAR-based techniques for measuring 3D motion on landslides was demonstrated.

  9. New GNSS velocity field and preliminary velocity model for Ecuador

    NASA Astrophysics Data System (ADS)

    Luna-Ludeña, Marco P.; Staller, Alejandra; Gaspar-Escribano, Jorge M.; Belén Benito, M.

    2016-04-01

    In this work, we present a new preliminary velocity model of Ecuador based on the GNSS data of the REGME network (continuous monitoring GNSS network). To date, there is no velocity model available for the country. The only existing model in the zone is the regional model VEMOS2009 for South America and Caribbean (Drewes and Heidbach, 2012). This model was developed from the SIRGAS station positions, the velocities of the SIRGAS-CON stations, and several geodynamics projects performed in the region. Just two continuous GNSS (cGNSS) stations of Ecuador were taking into account in the VEMOS2009 model. The first continuous station of the REGME network was established in 2008. At present, it is composed by 32 continuous GNSS stations, covering the country. All the stations provided data during at least two years. We processed the data of the 32 GNSS stations of REGME for the 2008-2014 period, as well as 20 IGS stations in order to link to the global reference frame IGb08 (ITRF2008). GPS data were processed using Bernese 5.0 software (Dach et al., 2007). We obtained and analyzed the GNSS coordinate time series of the 32 REGME stations and we calculated the GPS-derived horizontal velocity field of the country. Velocities in ITRF2008 were transformed into a South American fixed reference frame, using the Euler pole calculated from 8 cGNSS stations throughout this plate. Our velocity field is consistent with the tectonics of the country and contributes to a better understanding of it. From the horizontal velocity field, we determined a preliminary model using the kriging geostatistical technique. To check the results we use the cross-validation method. The differences between the observed and estimated values range from ± 5 mm. This is a new velocity model obtained from GNSS data for Ecuador.

  10. Motion field estimation for a dynamic scene using a 3D LiDAR.

    PubMed

    Li, Qingquan; Zhang, Liang; Mao, Qingzhou; Zou, Qin; Zhang, Pin; Feng, Shaojun; Ochieng, Washington

    2014-01-01

    This paper proposes a novel motion field estimation method based on a 3D light detection and ranging (LiDAR) sensor for motion sensing for intelligent driverless vehicles and active collision avoidance systems. Unlike multiple target tracking methods, which estimate the motion state of detected targets, such as cars and pedestrians, motion field estimation regards the whole scene as a motion field in which each little element has its own motion state. Compared to multiple target tracking, segmentation errors and data association errors have much less significance in motion field estimation, making it more accurate and robust. This paper presents an intact 3D LiDAR-based motion field estimation method, including pre-processing, a theoretical framework for the motion field estimation problem and practical solutions. The 3D LiDAR measurements are first projected to small-scale polar grids, and then, after data association and Kalman filtering, the motion state of every moving grid is estimated. To reduce computing time, a fast data association algorithm is proposed. Furthermore, considering the spatial correlation of motion among neighboring grids, a novel spatial-smoothing algorithm is also presented to optimize the motion field. The experimental results using several data sets captured in different cities indicate that the proposed motion field estimation is able to run in real-time and performs robustly and effectively. PMID:25207868

  11. Motion Field Estimation for a Dynamic Scene Using a 3D LiDAR

    PubMed Central

    Li, Qingquan; Zhang, Liang; Mao, Qingzhou; Zou, Qin; Zhang, Pin; Feng, Shaojun; Ochieng, Washington

    2014-01-01

    This paper proposes a novel motion field estimation method based on a 3D light detection and ranging (LiDAR) sensor for motion sensing for intelligent driverless vehicles and active collision avoidance systems. Unlike multiple target tracking methods, which estimate the motion state of detected targets, such as cars and pedestrians, motion field estimation regards the whole scene as a motion field in which each little element has its own motion state. Compared to multiple target tracking, segmentation errors and data association errors have much less significance in motion field estimation, making it more accurate and robust. This paper presents an intact 3D LiDAR-based motion field estimation method, including pre-processing, a theoretical framework for the motion field estimation problem and practical solutions. The 3D LiDAR measurements are first projected to small-scale polar grids, and then, after data association and Kalman filtering, the motion state of every moving grid is estimated. To reduce computing time, a fast data association algorithm is proposed. Furthermore, considering the spatial correlation of motion among neighboring grids, a novel spatial-smoothing algorithm is also presented to optimize the motion field. The experimental results using several data sets captured in different cities indicate that the proposed motion field estimation is able to run in real-time and performs robustly and effectively. PMID:25207868

  12. 3-D field computation: The near-triumph of commerical codes

    SciTech Connect

    Turner, L.R.

    1995-07-01

    In recent years, more and more of those who design and analyze magnets and other devices are using commercial codes rather than developing their own. This paper considers the commercial codes and the features available with them. Other recent trends with 3-D field computation include parallel computation and visualization methods such as virtual reality systems.

  13. Investigation of the 3-D actinic flux field in mountainous terrain

    NASA Astrophysics Data System (ADS)

    Wagner, J. E.; Angelini, F.; Blumthaler, M.; Fitzka, M.; Gobbi, G. P.; Kift, R.; Kreuter, A.; Rieder, H. E.; Simic, S.; Webb, A.; Weihs, P.

    2011-11-01

    During three field campaigns spectral actinic flux was measured from 290-500 nm under clear sky conditions in Alpine terrain and the associated O3- and NO2-photolysis frequencies were calculated and the measurement products were then compared with 1-D- and 3-D-model calculations. To do this 3-D-radiative transfer model was adapted for actinic flux calculations in mountainous terrain and the maps of the actinic flux field at the surface, calculated with the 3-D-radiative transfer model, are given. The differences between the 3-D- and 1-D-model results for selected days during the campaigns are shown, together with the ratios of the modeled actinic flux values to the measurements. In many cases the 1-D-model overestimates actinic flux by more than the measurement uncertainty of 10%. The results of using a 3-D-model generally show significantly lower values, and can underestimate the actinic flux by up to 30%. This case study attempts to quantify the impact of snow cover in combination with topography on spectral actinic flux. The impact of snow cover on the actinic flux was ~ 25% in narrow snow covered valleys, but for snow free areas there were no significant changes due snow cover in the surrounding area and it is found that the effect snow-cover at distances over 5 km from the point of interest was below 5%. Overall the 3-D-model can calculate actinic flux to the same accuracy as the 1-D-model for single points, but gives a much more realistic view of the surface actinic flux field in mountains as topography and obstruction of the horizon are taken into account.

  14. Investigation of the 3-D actinic flux field in mountainous terrain

    PubMed Central

    Wagner, J.E.; Angelini, F.; Blumthaler, M.; Fitzka, M.; Gobbi, G.P.; Kift, R.; Kreuter, A.; Rieder, H.E.; Simic, S.; Webb, A.; Weihs, P.

    2011-01-01

    During three field campaigns spectral actinic flux was measured from 290–500 nm under clear sky conditions in Alpine terrain and the associated O3- and NO2-photolysis frequencies were calculated and the measurement products were then compared with 1-D- and 3-D-model calculations. To do this 3-D-radiative transfer model was adapted for actinic flux calculations in mountainous terrain and the maps of the actinic flux field at the surface, calculated with the 3-D-radiative transfer model, are given. The differences between the 3-D- and 1-D-model results for selected days during the campaigns are shown, together with the ratios of the modeled actinic flux values to the measurements. In many cases the 1-D-model overestimates actinic flux by more than the measurement uncertainty of 10%. The results of using a 3-D-model generally show significantly lower values, and can underestimate the actinic flux by up to 30%. This case study attempts to quantify the impact of snow cover in combination with topography on spectral actinic flux. The impact of snow cover on the actinic flux was ~ 25% in narrow snow covered valleys, but for snow free areas there were no significant changes due snow cover in the surrounding area and it is found that the effect snow-cover at distances over 5 km from the point of interest was below 5%. Overall the 3-D-model can calculate actinic flux to the same accuracy as the 1-D-model for single points, but gives a much more realistic view of the surface actinic flux field in mountains as topography and obstruction of the horizon are taken into account. PMID:26412915

  15. Seismicity patterns along the Ecuadorian subduction zone: new constraints from earthquake location in a 3-D a priori velocity model

    NASA Astrophysics Data System (ADS)

    Font, Yvonne; Segovia, Monica; Vaca, Sandro; Theunissen, Thomas

    2013-04-01

    To improve earthquake location, we create a 3-D a priori P-wave velocity model (3-DVM) that approximates the large velocity variations of the Ecuadorian subduction system. The 3-DVM is constructed from the integration of geophysical and geological data that depend on the structural geometry and velocity properties of the crust and the upper mantle. In addition, specific station selection is carried out to compensate for the high station density on the Andean Chain. 3-D synthetic experiments are then designed to evaluate the network capacity to recover the event position using only P arrivals and the MAXI technique. Three synthetic earthquake location experiments are proposed: (1) noise-free and (2) noisy arrivals used in the 3-DVM, and (3) noise-free arrivals used in a 1-DVM. Synthetic results indicate that, under the best conditions (exact arrival data set and 3-DVM), the spatiotemporal configuration of the Ecuadorian network can accurately locate 70 per cent of events in the frontal part of the subduction zone (average azimuthal gap is 289° ± 44°). Noisy P arrivals (up to ± 0.3 s) can accurately located 50 per cent of earthquakes. Processing earthquake location within a 1-DVM almost never allows accurate hypocentre position for offshore earthquakes (15 per cent), which highlights the role of using a 3-DVM in subduction zone. For the application to real data, the seismicity distribution from the 3-D-MAXI catalogue is also compared to the determinations obtained in a 1-D-layered VM. In addition to good-quality location uncertainties, the clustering and the depth distribution confirm the 3-D-MAXI catalogue reliability. The pattern of the seismicity distribution (a 13 yr record during the inter-seismic period of the seismic cycle) is compared to the pattern of rupture zone and asperity of the Mw = 7.9 1942 and the Mw = 7.7 1958 events (the Mw = 8.8 1906 asperity patch is not defined). We observe that the nucleation of 1942, 1958 and 1906 events coincides with

  16. 3-D FEM field analysis in controlled-PM LSM for Maglev vehicle

    SciTech Connect

    Yoshida, Kinjiro; Lee, J.; Kim, Y.J.

    1997-03-01

    The magnetic fields in the controlled-PM LSM for Maglev vehicle, of which the width is not only finite with lateral edges, but also an effective electric-airgap is very large, are accurately analyzed by using 3-D FEM. The lateral airgap-flux due to lateral edges of the machine is made clear and its effects on thrust and lift forces are evaluated quantitatively from the comparison with 2-D FEA. The accuracy of 3-D FEA is verified by comparing the calculated results with the measured values.

  17. 3-D P- and S-wave velocity structure and low-frequency earthquake locations in the Parkfield, California region

    NASA Astrophysics Data System (ADS)

    Zeng, Xiangfang; Thurber, Clifford H.; Shelly, David R.; Harrington, Rebecca M.; Cochran, Elizabeth S.; Bennington, Ninfa L.; Peterson, Dana; Guo, Bin; McClement, Kara

    2016-09-01

    To refine the 3-D seismic velocity model in the greater Parkfield, California region, a new data set including regular earthquakes, shots, quarry blasts and low-frequency earthquakes (LFEs) was assembled. Hundreds of traces of each LFE family at two temporary arrays were stacked with time-frequency domain phase weighted stacking method to improve signal-to-noise ratio. We extend our model resolution to lower crustal depth with LFE data. Our result images not only previously identified features but also low velocity zones (LVZs) in the area around the LFEs and the lower crust beneath the southern Rinconada Fault. The former LVZ is consistent with high fluid pressure that can account for several aspects of LFE behaviour. The latter LVZ is consistent with a high conductivity zone in magnetotelluric studies. A new Vs model was developed with S picks that were obtained with a new autopicker. At shallow depth, the low Vs areas underlie the strongest shaking areas in the 2004 Parkfield earthquake. We relocate LFE families and analyse the location uncertainties with the NonLinLoc and tomoDD codes. The two methods yield similar results.

  18. Hypocenter relocation using a fast grid search method and a 3-D seismic velocity model for the Sumatra region

    SciTech Connect

    Nugroho, Hendro; Widiyantoro, Sri; Nugraha, Andri Dian

    2013-09-09

    Determination of earthquake hypocenter in Indonesia conducted by the Meteorological, Climatological, and Geophysical Agency (MCGA) has still used a 1-D seismic velocity model. In this research, we have applied a Fast Grid Search (FGM) method and a 3-D velocity model resulting from tomographic imaging to relocate earthquakes in the Sumatran region. The data were taken from the MCGA data catalog from 2009 to 2011 comprising of subduction zone and on land fault earthquakes with magnitude greater than 4 Mw. Our preliminary results show some significant changes in the depths of the relocated earthquakes which are in general deeper than the depths of hypocenters from the MCGA data catalog. The residual times resulting from the relocation process are smaller than those prior to the relocation. Encouraged by these results, we will continue to conduct hypocenter relocation for all events from the MCGA data catalog periodically in order to produce a new data catalog with good quality. We hope that the new data catalog will be useful for further studies.

  19. Moving from Batch to Field Using the RT3D Reactive Transport Modeling System

    NASA Astrophysics Data System (ADS)

    Clement, T. P.; Gautam, T. R.

    2002-12-01

    The public domain reactive transport code RT3D (Clement, 1997) is a general-purpose numerical code for solving coupled, multi-species reactive transport in saturated groundwater systems. The code uses MODFLOW to simulate flow and several modules of MT3DMS to simulate the advection and dispersion processes. RT3D employs the operator-split strategy which allows the code solve the coupled reactive transport problem in a modular fashion. The coupling between reaction and transport is defined through a separate module where the reaction equations are specified. The code supports a versatile user-defined reaction option that allows users to define their own reaction system through a Fortran-90 subroutine, known as the RT3D-reaction package. Further a utility code, known as BATCHRXN, allows the users to independently test and debug their reaction package. To analyze a new reaction system at a batch scale, users should first run BATCHRXN to test the ability of their reaction package to model the batch data. After testing, the reaction package can simply be ported to the RT3D environment to study the model response under 1-, 2-, or 3-dimensional transport conditions. This paper presents example problems that demonstrate the methods for moving from batch to field-scale simulations using BATCHRXN and RT3D codes. The first example describes a simple first-order reaction system for simulating the sequential degradation of Tetrachloroethene (PCE) and its daughter products. The second example uses a relatively complex reaction system for describing the multiple degradation pathways of Tetrachloroethane (PCA) and its daughter products. References 1) Clement, T.P, RT3D - A modular computer code for simulating reactive multi-species transport in 3-Dimensional groundwater aquifers, Battelle Pacific Northwest National Laboratory Research Report, PNNL-SA-28967, September, 1997. Available at: http://bioprocess.pnl.gov/rt3d.htm.

  20. HOSVD-Based 3D Active Appearance Model: Segmentation of Lung Fields in CT Images.

    PubMed

    Wang, Qingzhu; Kang, Wanjun; Hu, Haihui; Wang, Bin

    2016-07-01

    An Active Appearance Model (AAM) is a computer vision model which can be used to effectively segment lung fields in CT images. However, the fitting result is often inadequate when the lungs are affected by high-density pathologies. To overcome this problem, we propose a Higher-order Singular Value Decomposition (HOSVD)-based Three-dimensional (3D) AAM. An evaluation was performed on 310 diseased lungs form the Lung Image Database Consortium Image Collection. Other contemporary AAMs operate directly on patterns represented by vectors, i.e., before applying the AAM to a 3D lung volume,it has to be vectorized first into a vector pattern by some technique like concatenation. However, some implicit structural or local contextual information may be lost in this transformation. According to the nature of the 3D lung volume, HOSVD is introduced to represent and process the lung in tensor space. Our method can not only directly operate on the original 3D tensor patterns, but also efficiently reduce the computer memory usage. The evaluation resulted in an average Dice coefficient of 97.0 % ± 0.59 %, a mean absolute surface distance error of 1.0403 ± 0.5716 mm, a mean border positioning errors of 0.9187 ± 0.5381 pixel, and a Hausdorff Distance of 20.4064 ± 4.3855, respectively. Experimental results showed that our methods delivered significant and better segmentation results, compared with the three other model-based lung segmentation approaches, namely 3D Snake, 3D ASM and 3D AAM. PMID:27277277

  1. Fast 3D Spatial EPR Imaging Using Spiral Magnetic Field Gradient

    PubMed Central

    Deng, Yuanmu; Petryakov, Sergy; He, Guanglong; Kesselring, Eric; Kuppusamy, Periannan; Zweier, Jay L.

    2007-01-01

    Electron paramagnetic resonance imaging (EPRI) provides direct detection and mapping of free radicals. The continuous wave (CW) EPRI technique, in particular, has been widely used in a variety of applications in the fields of biology and medicine due to its high sensitivity and applicability to a wide range of free radicals and paramagnetic species. However, the technique requires long image acquisition periods, and this limits its use for many in vivo applications where relatively rapid changes occur in the magnitude and distribution of spins. Therefore, there has been a great need to develop fast EPRI techniques. We report the development of a fast 3D CW EPRI technique using spiral magnetic field gradient. By spiraling the magnetic field gradient and stepping the main magnetic field, this approach acquires a 3D image in one sweep of the main magnetic field, enabling significant reduction of the imaging time. A direct one-stage 3D image reconstruction algorithm, modified for reconstruction of the EPR images from the projections acquired with the spiral magnetic field gradient, was used. We demonstrated using a home-built L-band EPR system that the spiral magnetic field gradient technique enabled a 4 to 7-fold accelerated acquisition of projections. This technique has great potential for in vivo studies of free radicals and their metabolism. PMID:17267252

  2. 3D Simultaneous Traveltime Inversion for Velocity Structure, Hypocenter Locations, and Reflector Geometry Using Multiple Classes of Arrivals

    NASA Astrophysics Data System (ADS)

    Bai, Chao-ying; Huang, Guo-jiao; Li, Xing-wang; Greenhalgh, Stewart

    2015-10-01

    Traditionally, traveltime tomography entails inversion of either the velocity field and the reflector geometry sequentially, or the velocity field and the hypocenter locations simultaneously or in a cascaded fashion, but seldom are all three types (velocities, geometry of reflectors, and source locations) updated simultaneously because of the compromise between the different classes of model variable and the lack of different seismic phases to constrain these variables. By using a state-of-the-art ray-tracing algorithm for the first and later arrivals combined with a popular linearized inversion solver, it is possible to simultaneously recover the three classes of model variables. In the work discussed in this paper we combined the multistage irregular shortest-path ray-tracing algorithm with a subspace inversion solver to achieve simultaneous inversion of multi-class variables, using arrival times for different phases to concurrently obtain the velocity field, the reflector shapes, and the hypocenter locations. Simulation and comparison tests for two sets of source-receiver arrangements (one the ideal case and the other an approximated real case) indicate that the combined triple-class inversion algorithm is capable of obtaining nearly the same results as the double-class affect inversion scheme (velocity and reflector geometry, or velocity and source locations) even if a lower ray density and irregular source-receiver geometry are used to simulate the real situation. In addition, the new simultaneous inversion method is not sensitive to a modest amount of picking error in the traveltime data and reasonable uncertainty in earthquake hypocenter locations, which shows it to be a feasible and promising approach in real applications.

  3. Calculation of three-dimensional (3-D) internal flow by means of the velocity-vorticity formulation on a staggered grid

    NASA Technical Reports Server (NTRS)

    Stremel, Paul M.

    1995-01-01

    A method has been developed to accurately compute the viscous flow in three-dimensional (3-D) enclosures. This method is the 3-D extension of a two-dimensional (2-D) method developed for the calculation of flow over airfoils. The 2-D method has been tested extensively and has been shown to accurately reproduce experimental results. As in the 2-D method, the 3-D method provides for the non-iterative solution of the incompressible Navier-Stokes equations by means of a fully coupled implicit technique. The solution is calculated on a body fitted computational mesh incorporating a staggered grid methodology. In the staggered grid method, the three components of vorticity are defined at the centers of the computational cell sides, while the velocity components are defined as normal vectors at the centers of the computational cell faces. The staggered grid orientation provides for the accurate definition of the vorticity components at the vorticity locations, the divergence of vorticity at the mesh cell nodes and the conservation of mass at the mesh cell centers. The solution is obtained by utilizing a fractional step solution technique in the three coordinate directions. The boundary conditions for the vorticity and velocity are calculated implicitly as part of the solution. The method provides for the non-iterative solution of the flow field and satisfies the conservation of mass and divergence of vorticity to machine zero at each time step. To test the method, the calculation of simple driven cavity flows have been computed. The driven cavity flow is defined as the flow in an enclosure driven by a moving upper plate at the top of the enclosure. To demonstrate the ability of the method to predict the flow in arbitrary cavities, results will he shown for both cubic and curved cavities.

  4. Zemmouri earthquake rupture zone (Mw 6.8, Algeria): Aftershocks sequence relocation and 3D velocity model

    NASA Astrophysics Data System (ADS)

    Ayadi, A.; Dorbath, C.; Ousadou, F.; Maouche, S.; Chikh, M.; Bounif, M. A.; Meghraoui, M.

    2008-09-01

    We analyze the aftershocks sequence of the Zemmouri thrust faulting earthquake (21 May 2003, Mw 6.8) located east of Algiers in the Tell Atlas. The seismic sequence located during ˜2 months following the mainshock is made of more than 1500 earthquakes and extends NE-SW along a ˜60-km fault rupture zone crossing the coastline. The earthquake relocation was performed using handpicked P and S phases located with the tomoDD in a detailed 3D velocity structure of the epicentral area. Contrasts between velocity patches seem to correlate with contacts between granitic-volcanic basement rocks and the sedimentary formation of the eastern Mitidja basin. The aftershock sequence exhibits at least three seismic clouds and a well-defined SE-dipping main fault geometry that reflects the complex rupture. The distribution of seismic events presents a clear contrast between a dense SW zone and a NE zone with scattered aftershocks. We observe that the mainshock locates between the SW and NE seismic zones; it also lies at the NNS-SSE contact that separates a basement block to the east and sedimentary formations to the west. The aftershock distribution also suggests fault bifurcation at the SW end of the fault rupture, with a 20-km-long ˜N 100° trending seismic cluster, with a vertical fault geometry parallel to the coastline juxtaposed. Another aftershock cloud may correspond to 75° SE dipping fault. The fault geometry and related SW branches may illustrate the interference between pre-existing fault structures and the SW rupture propagation. The rupture zone, related kinematics, and velocity contrasts obtained from the aftershocks distribution are in agreement with the coastal uplift and reflect the characteristics of an active zone controlled by convergent movements at a plate boundary.

  5. Wave optics theory and 3-D deconvolution for the light field microscope

    PubMed Central

    Broxton, Michael; Grosenick, Logan; Yang, Samuel; Cohen, Noy; Andalman, Aaron; Deisseroth, Karl; Levoy, Marc

    2013-01-01

    Light field microscopy is a new technique for high-speed volumetric imaging of weakly scattering or fluorescent specimens. It employs an array of microlenses to trade off spatial resolution against angular resolution, thereby allowing a 4-D light field to be captured using a single photographic exposure without the need for scanning. The recorded light field can then be used to computationally reconstruct a full volume. In this paper, we present an optical model for light field microscopy based on wave optics, instead of previously reported ray optics models. We also present a 3-D deconvolution method for light field microscopy that is able to reconstruct volumes at higher spatial resolution, and with better optical sectioning, than previously reported. To accomplish this, we take advantage of the dense spatio-angular sampling provided by a microlens array at axial positions away from the native object plane. This dense sampling permits us to decode aliasing present in the light field to reconstruct high-frequency information. We formulate our method as an inverse problem for reconstructing the 3-D volume, which we solve using a GPU-accelerated iterative algorithm. Theoretical limits on the depth-dependent lateral resolution of the reconstructed volumes are derived. We show that these limits are in good agreement with experimental results on a standard USAF 1951 resolution target. Finally, we present 3-D reconstructions of pollen grains that demonstrate the improvements in fidelity made possible by our method. PMID:24150383

  6. 3D Extended Logging for Geothermal Resources: Field Trials with the Geo-Bilt System

    SciTech Connect

    Mallan, R; Wilt, M; Kirkendall, B; Kasameyer, P

    2002-05-29

    Geo-BILT (Geothermal Borehole Induction Logging Tool) is an extended induction logging tool designed for 3D resistivity imaging around a single borehole. The tool was developed for deployment in high temperature geothermal wells under a joint program funded by the California Energy Commission, Electromagnetic Instruments (EMI) and the U.S. Department of Energy. EM1 was responsible for tool design and manufacture, and numerical modeling efforts were being addressed at Lawrence Livermore Laboratory (LLNL) and other contractors. The field deployment was done by EM1 and LLNL. The tool operates at frequencies from 2 to 42 kHz, and its design features a series of three-component magnetic sensors offset at 2 and 5 meters from a three-component magnetic source. The combined package makes it possible to do 3D resistivity imaging, deep into the formation, from a single well. The manufacture and testing of the tool was completed in spring of 2001, and the initial deployment of Geo-BILT occurred in May 2001 at the Lost Hills oil field in southern California at leases operated by Chevron USA. This site was chosen for the initial field test because of the favorable geological conditions and the availability of a number of wells suitable for tool deployment. The second deployment occurred in April 2002 at the Dixie Valley geothermal field, operated by Caithness Power LLC, in central Nevada. This constituted the first test in a high temperature environment. The Chevron site features a fiberglass-cased observation well in the vicinity of a water injector. The injected water, which is used for pressure maintenance and for secondary sweep of the heavy oil formation, has a much lower resistivity than the oil bearing formation. This, in addition to the non-uniform flow of this water, creates a 3D resistivity structure, which is analogous to conditions produced from flowing fractures adjacent to geothermal boreholes. Therefore, it is an excellent site for testing the 3D capability of

  7. Interval velocity analysis using wave field continuation

    SciTech Connect

    Zhusheng, Z. )

    1992-01-01

    In this paper, the author proposes a new interval velocity inversion method which, based on wave field continuation theory and fuzzy decision theory, uses CMP seismic gathers to automatically estimate interval velocity and two-way travel time in layered medium. The interval velocity calculated directly from wave field continuation is not well consistent with that derived from VSP data, the former is usually higher than the latter. Three major factors which influence the accuracy of interval velocity from wave field continuation are corrected, so that the two kinds of interval velocity are well consistent. This method brings better interval velocity, adapts weak reflection waves and resists noise well. It is a feasible method.

  8. Reconstruction of lava fields based on 3D and conventional images. Arenal volcano, Costa Rica.

    NASA Astrophysics Data System (ADS)

    Horvath, S.; Duarte, E.; Fernandez, E.

    2007-05-01

    , chemical composition, type of lava, velocity, etc. With all this information and photographs; real, visual and topographic images of the position and characters of the 1990s and 2000s lava flows, were obtained . An illustrative poster will be presented along with this abstract to show the construction process of such tool. Moreover, 3D animations will be present in the mentioned poster.

  9. Self-dual Maxwell field in 3D gravity with torsion

    SciTech Connect

    Blagojevic, M.; Cvetkovic, B.

    2008-08-15

    We study the system of a self-dual Maxwell field coupled to 3D gravity with torsion, with the Maxwell field modified by a topological mass term. General structure of the field equations reveals a new, dynamical role of the classical central charges, and gives a simple correspondence between self-dual solutions with torsion and their Riemannian counterparts. We construct two exact self-dual solutions, corresponding to the sectors with a massless and massive Maxwell field, and calculate their conserved charges.

  10. Decoding 3D search coil signals in a non-homogeneous magnetic field.

    PubMed

    Thomassen, Jakob S; Benedetto, Giacomo Di; Hess, Bernhard J M

    2010-06-18

    We present a method for recording eye-head movements with the magnetic search coil technique in a small external magnetic field. Since magnetic fields are typically non-linear, except in a relative small region in the center small field frames have not been used for head-unrestrained experiments in oculomotor studies. Here we present a method for recording 3D eye movements by accounting for the magnetic non-linearities using the Biot-Savart law. We show that the recording errors can be significantly reduced by monitoring current head position and thereby taking the location of the eye in the external magnetic field into account. PMID:20359490

  11. Using the CAVE virtual-reality environment as an aid to 3-D electromagnetic field computation

    SciTech Connect

    Turner, L.R.; Levine, D.; Huang, M.; Papka, M; Kettunen, L.

    1995-08-01

    One of the major problems in three-dimensional (3-D) field computation is visualizing the resulting 3-D field distributions. A virtual-reality environment, such as the CAVE, (CAVE Automatic Virtual Environment) is helping to overcome this problem, thus making the results of computation more usable for designers and users of magnets and other electromagnetic devices. As a demonstration of the capabilities of the CAVE, the elliptical multipole wiggler (EMW), an insertion device being designed for the Advanced Photon Source (APS) now being commissioned at Argonne National Laboratory (ANL), wa made visible, along with its fields and beam orbits. Other uses of the CAVE in preprocessing and postprocessing computation for electromagnetic applications are also discussed.

  12. Radial electric field 3D modeling for wire arrays driving dynamic hohlraums on Z.

    SciTech Connect

    Mock, Raymond Cecil

    2007-06-01

    The anode-cathode structure of the Z-machine wire array results in a higher negative radial electric field (Er) on the wires near the cathode relative to the anode. The magnitude of this field has been shown to anti-correlate with the axial radiation top/bottom symmetry in the DH (Dynamic Hohlraum). Using 3D modeling, the structure of this field is revealed for different wire-array configurations and for progressive mechanical alterations, providing insight for minimizing the negative Er on the wire array in the anode-to-cathode region of the DH. Also, the 3D model is compared to Sasorov's approximation, which describes Er at the surface of the wire in terms of wire-array parameters.

  13. Exploring Direct 3D Interaction for Full Horizontal Parallax Light Field Displays Using Leap Motion Controller

    PubMed Central

    Adhikarla, Vamsi Kiran; Sodnik, Jaka; Szolgay, Peter; Jakus, Grega

    2015-01-01

    This paper reports on the design and evaluation of direct 3D gesture interaction with a full horizontal parallax light field display. A light field display defines a visual scene using directional light beams emitted from multiple light sources as if they are emitted from scene points. Each scene point is rendered individually resulting in more realistic and accurate 3D visualization compared to other 3D displaying technologies. We propose an interaction setup combining the visualization of objects within the Field Of View (FOV) of a light field display and their selection through freehand gesture tracked by the Leap Motion Controller. The accuracy and usefulness of the proposed interaction setup was also evaluated in a user study with test subjects. The results of the study revealed high user preference for free hand interaction with light field display as well as relatively low cognitive demand of this technique. Further, our results also revealed some limitations and adjustments of the proposed setup to be addressed in future work. PMID:25875189

  14. Exploring direct 3D interaction for full horizontal parallax light field displays using leap motion controller.

    PubMed

    Adhikarla, Vamsi Kiran; Sodnik, Jaka; Szolgay, Peter; Jakus, Grega

    2015-01-01

    This paper reports on the design and evaluation of direct 3D gesture interaction with a full horizontal parallax light field display. A light field display defines a visual scene using directional light beams emitted from multiple light sources as if they are emitted from scene points. Each scene point is rendered individually resulting in more realistic and accurate 3D visualization compared to other 3D displaying technologies. We propose an interaction setup combining the visualization of objects within the Field Of View (FOV) of a light field display and their selection through freehand gesture tracked by the Leap Motion Controller. The accuracy and usefulness of the proposed interaction setup was also evaluated in a user study with test subjects. The results of the study revealed high user preference for free hand interaction with light field display as well as relatively low cognitive demand of this technique. Further, our results also revealed some limitations and adjustments of the proposed setup to be addressed in future work. PMID:25875189

  15. Constructing a 3D Crustal Model Across the Entire Contiguous US Using Broadband Rayleigh Wave Phase Velocity and Ellipticity Measurements

    NASA Astrophysics Data System (ADS)

    Lin, F. C.; Schmandt, B.

    2015-12-01

    Imaging the crust and lithosphere structure beneath North America is one of the primary targets for the NSF-funded EarthScope project. In this study, we apply the recently developed ambient noise and surface wave tomography methods to construct a detailed 3D crustal model across the entire contiguous US using USArray data between January 2007 and May 2015. By using both Rayleigh wave phase velocity and ellipticity measurements between 8 and 100 sec period, the shear velocity structure can be well resolved within the five crustal layers we modeled: three upper crust, one middle crust, and one lower crust. Clear correlations are observed between the resolved velocity anomalies and known geological features at all depths. In the uppermost crust, slow Vs anomalies are observed within major sedimentary environments such as the Williston Basin, Denver Basin, and Mississippi embayment, and fast Vs anomalies are observed in environments with deeply exhumed bedrock outcrops at the surface including the Laurentian Highlands, Ouachita-Ozark Interior Highlands, and Appalachian Highlands. In the deeper upper crust, slow anomalies are observed in deep sedimentary basins such as the Green River Basin, Appalachian Basin, Southern Oklahoma Aulacogen, and areas surrounding the Gulf of Mexico. Fast anomalies, on the other hand, are observed in the Colorado Plateau, within the Great Plains between the Front Ranges and Midcontinental Rift, and east of the Appalachian Mountains. At this depth, the Midcontinental Rift and Grenville Front clearly correlate well with various velocity structure boundaries. In the middle crust, slow anomalies are mostly observed in the tectonically active areas in the western US, but relatively slow anomalies are also observed southeast of the Precambrian Rift Margins. At this depth, fast anomalies are observed beneath various deep sedimentary basins such as the Southern Oklahoma Aulacogen, Appalachian Basin, and Central Valley. In the lower crust, a clear

  16. Next-generation seismic experiments - II: wide-angle, multi-azimuth, 3-D, full-waveform inversion of sparse field data

    NASA Astrophysics Data System (ADS)

    Morgan, Joanna; Warner, Michael; Arnoux, Gillean; Hooft, Emilie; Toomey, Douglas; VanderBeek, Brandon; Wilcock, William

    2016-02-01

    3-D full-waveform inversion (FWI) is an advanced seismic imaging technique that has been widely adopted by the oil and gas industry to obtain high-fidelity models of P-wave velocity that lead to improvements in migrated images of the reservoir. Most industrial applications of 3-D FWI model the acoustic wavefield, often account for the kinematic effect of anisotropy, and focus on matching the low-frequency component of the early arriving refractions that are most sensitive to P-wave velocity structure. Here, we have adopted the same approach in an application of 3-D acoustic, anisotropic FWI to an ocean-bottom-seismometer (OBS) field data set acquired across the Endeavour oceanic spreading centre in the northeastern Pacific. Starting models for P-wave velocity and anisotropy were obtained from traveltime tomography; during FWI, velocity is updated whereas anisotropy is kept fixed. We demonstrate that, for the Endeavour field data set, 3-D FWI is able to recover fine-scale velocity structure with a resolution that is 2-4 times better than conventional traveltime tomography. Quality assurance procedures have been employed to monitor each step of the workflow; these are time consuming but critical to the development of a successful inversion strategy. Finally, a suite of checkerboard tests has been performed which shows that the full potential resolution of FWI can be obtained if we acquire a 3-D survey with a slightly denser shot and receiver spacing than is usual for an academic experiment. We anticipate that this exciting development will encourage future seismic investigations of earth science targets that would benefit from the superior resolution offered by 3-D FWI.

  17. Decoding 3-D Reach and Grasp Kinematics from High-Frequency Local Field Potentials in Primate Primary Motor Cortex

    PubMed Central

    Zhuang, Jun; Vargas-Irwin, Carlos; Donoghue, John P.

    2011-01-01

    Intracortical microelectrode array recordings generate a variety of neural signals with potential application as control signals in neural interface systems. Previous studies have focused on single and multiunit activity, as well as low frequency local field potentials (LFPs), but have not explored higher frequency (>200 Hz) LFPs. In addition, the potential to decode three dimensional (3-D) reach and grasp kinematics based on LFPs has not been demonstrated. Here, we use mutual information and decoding analyses to probe the information content about 3-D reaching and grasping of 7 different LFP frequency bands in the range of 0.3 Hz – 400 Hz. LFPs were recorded via 96-microelectrode arrays in primary motor cortex (M1) of two monkeys performing free reaching to grasp moving objects. Mutual information analyses revealed that higher frequency bands (e.g. 100 – 200 Hz and 200 – 400 Hz) carried the most information about the examined kinematics. Furthermore, Kalman filter decoding revealed that broadband high frequency LFPs, likely reflecting multiunit activity, provided the best decoding performance as well as substantial accuracy in reconstructing reach kinematics, grasp aperture and aperture velocity. These results indicate that LFPs, especially high frequency bands, could be useful signals for neural interfaces controlling 3-D reach and grasp kinematics. PMID:20403782

  18. Surface strain-field determination of tympanic membrane using 3D-digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Hernandez-Montes, María del S.; Mendoza Santoyo, Fernando; Muñoz, Silvino; Perez, Carlos; de la Torre, Manuel; Flores, Mauricio; Alvarez, Luis

    2015-08-01

    In order to increase the understanding of soft tissues mechanical properties, 3D Digital Holographic Interferometry (3D-DHI) was used to quantify the strain-field on a cat tympanic membrane (TM) surface. The experiments were carried out applying a constant sound-stimuli pressure of 90 dB SPL (0.632 Pa) on the TM at 1.2 kHz. The technique allows the accurate acquisition of the micro-displacement data along the x, y and z directions, which is a must for a full characterization of the tissue mechanical behavior under load, and for the calculation of the strain-field in situ. The displacements repeatability in z direction shows a standard deviation of 0.062 μm at 95% confidence level. In order to realize the full 3D characterization correctly the contour of the TM surface was measured employing the optically non-contact two-illumination positions contouring method. The x, y and z displacements combined with the TM contour data allow the evaluation its strain-field by spatially differentiating the u(m,n), v(m,n), and w(m,n) deformation components. The accurate and correct determination of the TM strain-field leads to describing its elasticity, which is an important parameter needed to improve ear biomechanics studies, audition processes and TM mobility in both experimental measurements and theoretical analysis of ear functionality and its modeling.

  19. Solar Wind Halo Formation by the Scattering of the Strahl via Direct Cluster/PEACE Observations of the 3D Velocity Distribution Function

    NASA Technical Reports Server (NTRS)

    Figueroa-Vinas, Adolfo; Gurgiolo, Chris A.; Nieves-Chinchilla, Teresa; Goldstein, Melvyn L.

    2010-01-01

    It has been suggested by a number of authors that the solar wind electron halo can be formed by the scattering of the strahl. On frequent occasions we have observed in electron angular skymaps (Phi/Theta-plots) of the electron 3D velocity distribution functions) a bursty-filament of particles connecting the strahl to the solar wind core-halo. These are seen over a very limited energy range. When the magnetic field is well off the nominal solar wind flow direction such filaments are inconsistent with any local forces and are probably the result of strong scattering. Furthermore, observations indicates that the strahl component is frequently and significantly anisotropic (Tper/Tpal approx.2). This provides a possible free energy source for the excitation of whistler waves as a possible scattering mechanism. The empirical observational evidence between the halo and the strahl suggests that the strahl population may be, at least in part, the source of the halo component.

  20. Background and pickup ion velocity distribution dynamics in Titan's plasma environment: 3D hybrid simulation and comparison with CAPS T9 observations

    NASA Astrophysics Data System (ADS)

    Lipatov, A. S.; Sittler, E. C.; Hartle, R. E.; Cooper, J. F.; Simpson, D. G.

    2011-09-01

    In this report we discuss the ion velocity distribution dynamics from the 3D hybrid simulation. In our model the background, pickup, and ionospheric ions are considered as a particles, whereas the electrons are described as a fluid. Inhomogeneous photoionization, electron-impact ionization and charge exchange are included in our model. We also take into account the collisions between the ions and neutrals. The current simulation shows that mass loading by pickup ions H,H2+, CH4+ and N2+ is stronger than in the previous simulations when O + ions are introduced into the background plasma. In our hybrid simulations we use Chamberlain profiles for the atmospheric components. We also include a simple ionosphere model with average mass M = 28 amu ions that were generated inside the ionosphere. The moon is considered as a weakly conducting body. Special attention will be paid to comparing the simulated pickup ion velocity distribution with CAPS T9 observations. Our simulation shows an asymmetry of the ion density distribution and the magnetic field, including the formation of the Alfvén wing-like structures. The simulation also shows that the ring-like velocity distribution for pickup ions relaxes to a Maxwellian core and a shell-like halo.

  1. Background and Pickup Ion Velocity Distribution Dynamics in Titan's Plasma Environment: 3D Hybrid Simulation and Comparison with CAPS T9 Observations

    NASA Technical Reports Server (NTRS)

    Lipatov, A. S.; Sittler, E. C., Jr.; Hartle, R. E.; Cooper, J. F.; Simpson, D. G.

    2011-01-01

    In this report we discuss the ion velocity distribution dynamics from the 3D hybrid simulation. In our model the background, pickup, and ionospheric ions are considered as a particles, whereas the electrons are described as a fluid. Inhomogeneous photoionization, electron-impact ionization and charge exchange are included in our model. We also take into account the collisions between the ions and neutrals. The current simulation shows that mass loading by pickup ions H(+); H2(+), CH4(+) and N2(+) is stronger than in the previous simulations when O+ ions are introduced into the background plasma. In our hybrid simulations we use Chamberlain profiles for the atmospheric components. We also include a simple ionosphere model with average mass M = 28 amu ions that were generated inside the ionosphere. The moon is considered as a weakly conducting body. Special attention will be paid to comparing the simulated pickup ion velocity distribution with CAPS T9 observations. Our simulation shows an asymmetry of the ion density distribution and the magnetic field, including the formation of the Alfve n wing-like structures. The simulation also shows that the ring-like velocity distribution for pickup ions relaxes to a Maxwellian core and a shell-like halo.

  2. Results From a Borehole Seismometer Array II: 3-D Mapping of an Active Geothermal Field at the Kilauea Lower Rift Zone

    NASA Astrophysics Data System (ADS)

    Shalev, E.; Kenedi, C. L.; Malin, P.

    2008-12-01

    The geothermal power plant in Puna, in southeastern Hawaii, is located in a section of the Kilauea Lower East Rift Zone that was resurfaced by lava flows as recently as 1955, 1960, and 1972. In 2006 a seismic array consisting of eight 3-component stations was installed around the geothermal field in Puna. The instrument depths range from 24 to 210 m. The shallower instruments have 2 Hz geophones and the deeper have 4.5 Hz geophones. 3-D tomographic analyses of P-wave velocity, S-wave velocity, and the Vp/Vs ratio show an area of very fast P-wave velocity at the relatively shallow depth of 2.5 km in the southern section of the field. The same area shows moderate S-wave velocity. This high P-wave velocity anomaly at the southern part of the geothermal field may indicate the presence of dense rock material usually found at greater depths.

  3. Field structure of collapsing wave packets in 3D strong Langmuir turbulence

    NASA Technical Reports Server (NTRS)

    Newman, D. L.; Robinson, P. A.; Goldman, M. V.

    1989-01-01

    A simple model is constructed for the electric fields in the collapsing wave packets found in 3D simulations of driven and damped isotropic strong Langmuir turbulence. This model, based on a spherical-harmonic decomposition of the electrostatic potential, accounts for the distribution of wave-packet shapes observed in the simulations, particularly the predominance of oblate wave packets. In contrast with predictions for undamped and undriven subsonic collapse of scalar fields, oblate vector-field wave packets do not flatten during collapse but, instead, remain approximately self-similar and rigid.

  4. Kinetic turbulence in 3D collisionless magnetic reconnection with a guide magnetic field

    NASA Astrophysics Data System (ADS)

    Alejandro Munoz Sepulveda, Patricio; Kilian, Patrick; Jain, Neeraj; Büchner, Jörg

    2016-04-01

    The features of kinetic plasma turbulence developed during non-relativistic 3D collisionless magnetic reconnection are still not fully understood. This is specially true under the influence of a strong magnetic guide field, a scenario common in space plasmas such as in the solar corona and also in laboratory experiments such as MRX or VINETA II. Therefore, we study the mechanisms and micro-instabilities leading to the development of turbulence during 3D magnetic reconnection with a fully kinetic PIC code, emphasizing the role of the guide field with an initial setup suitable for the aforementioned environments. We also clarify the relations between these processes and the generation of non-thermal populations and particle acceleration.

  5. 3D Kinetic Simulations of Topography-Induced Electric Fields at Itokawa Asteroid

    NASA Astrophysics Data System (ADS)

    Zimmerman, M. I.

    2015-12-01

    Results from a new 3D kinetic simulation code will be presented, showing how Itokawa's interaction with the solar wind plasma creates an ever-evolving electric field structure as the asteroid rotates. The simulations combine (1) a realistic surface shape model of Itokawa, (2) a careful and self-consistent accounting of surface charging processes, and (3) the freely-available FMMLib3d code library implementing the fast multipole method for electric field calculations. Fine details of the surface potential and electric grounding conditions, as revealed by this new code, could provide critical inputs into planning for a future asteroid retrieval mission in which extended, direct contact with the asteroid could occur.

  6. Global well-posedness to the 3-D incompressible inhomogeneous Navier-Stokes equations with a class of large velocity

    NASA Astrophysics Data System (ADS)

    Zhai, Cuili; Zhang, Ting

    2015-09-01

    In this article, we consider the global well-posedness to the 3-D incompressible inhomogeneous Navier-Stokes equations with a class of large velocity. More precisely, assuming a 0 ∈ B˙ q , 1 /3 q ( R 3 ) and u 0 = ( u0 h , u0 3 ) ∈ B˙ p , 1 - 1 + /3 p ( R 3 ) for p, q ∈ (1, 6) with sup ( /1 p , /1 q ) ≤ /1 3 + inf ( /1 p , /1 q ) , we prove that if C a↑0↑ B˙q1/3 q α (↑u0 3↑ B˙ p , 1 - 1 + /3 p/μ + 1 ) ≤ 1 , /C μ (↑u0 h↑ B˙ p , 1 - 1 + /3 p + ↑u03↑ B˙ p , 1 - 1 + /3 p 1 - α ↑u0h↑ B˙ p , 1 - 1 + /3 p α) ≤ 1 , then the system has a unique global solution a ∈ C ˜ ( [ 0 , ∞ ) ; B˙ q , 1 /3 q ( R 3 ) ) , u ∈ C ˜ ( [ 0 , ∞ ) ; B˙ p , 1 - 1 + /3 p ( R 3 ) ) ∩ L 1 ( R + ; B˙ p , 1 1 + /3 p ( R 3 ) ) . It improves the recent result of M. Paicu and P. Zhang [J. Funct. Anal. 262, 3556-3584 (2012)], where the exponent form of the initial smallness condition is replaced by a polynomial form.

  7. Blind Depth-variant Deconvolution of 3D Data in Wide-field Fluorescence Microscopy.

    PubMed

    Kim, Boyoung; Naemura, Takeshi

    2015-01-01

    This paper proposes a new deconvolution method for 3D fluorescence wide-field microscopy. Most previous methods are insufficient in terms of restoring a 3D cell structure, since a point spread function (PSF) is simply assumed as depth-invariant, whereas a PSF of microscopy changes significantly along the optical axis. A few methods that consider a depth-variant PSF have been proposed; however, they are impractical, since they are non-blind approaches that use a known PSF in a pre-measuring condition, whereas an imaging condition of a target image is different from that of the pre-measuring. To solve these problems, this paper proposes a blind approach to estimate depth-variant specimen-dependent PSF and restore 3D cell structure. It is shown by experiments on that the proposed method outperforms the previous ones in terms of suppressing axial blur. The proposed method is composed of the following three steps: First, a non-parametric averaged PSF is estimated by the Richardson Lucy algorithm, whose initial parameter is given by the central depth prediction from intensity analysis. Second, the estimated PSF is fitted to Gibson's parametric PSF model via optimization, and depth-variant PSFs are generated. Third, a 3D cell structure is restored by using a depth-variant version of a generalized expectation-maximization. PMID:25950821

  8. ARCHAEO-SCAN: Portable 3D shape measurement system for archaeological field work

    NASA Astrophysics Data System (ADS)

    Knopf, George K.; Nelson, Andrew J.

    2004-10-01

    Accurate measurement and thorough documentation of excavated artifacts are the essential tasks of archaeological fieldwork. The on-site recording and long-term preservation of fragile evidence can be improved using 3D spatial data acquisition and computer-aided modeling technologies. Once the artifact is digitized and geometry created in a virtual environment, the scientist can manipulate the pieces in a virtual reality environment to develop a "realistic" reconstruction of the object without physically handling or gluing the fragments. The ARCHAEO-SCAN system is a flexible, affordable 3D coordinate data acquisition and geometric modeling system for acquiring surface and shape information of small to medium sized artifacts and bone fragments. The shape measurement system is being developed to enable the field archaeologist to manually sweep the non-contact sensor head across the relic or artifact surface. A series of unique data acquisition, processing, registration and surface reconstruction algorithms are then used to integrate 3D coordinate information from multiple views into a single reference frame. A novel technique for automatically creating a hexahedral mesh of the recovered fragments is presented. The 3D model acquisition system is designed to operate from a standard laptop with minimal additional hardware and proprietary software support. The captured shape data can be pre-processed and displayed on site, stored digitally on a CD, or transmitted via the Internet to the researcher's home institution.

  9. Rigorous analysis of an electric-field-driven liquid crystal lens for 3D displays

    NASA Astrophysics Data System (ADS)

    Kim, Bong-Sik; Lee, Seung-Chul; Park, Woo-Sang

    2014-08-01

    We numerically analyzed the optical performance of an electric field driven liquid crystal (ELC) lens adopted for 3-dimensional liquid crystal displays (3D-LCDs) through rigorous ray tracing. For the calculation, we first obtain the director distribution profile of the liquid crystals by using the Erickson-Leslie motional equation; then, we calculate the transmission of light through the ELC lens by using the extended Jones matrix method. The simulation was carried out for a 9view 3D-LCD with a diagonal of 17.1 inches, where the ELC lens was slanted to achieve natural stereoscopic images. The results show that each view exists separately according to the viewing position at an optimum viewing distance of 80 cm. In addition, our simulation results provide a quantitative explanation for the ghost or blurred images between views observed from a 3D-LCD with an ELC lens. The numerical simulations are also shown to be in good agreement with the experimental results. The present simulation method is expected to provide optimum design conditions for obtaining natural 3D images by rigorously analyzing the optical functionalities of an ELC lens.

  10. Direct measurement of particle size and 3D velocity of a gas-solid pipe flow with digital holographic particle tracking velocimetry.

    PubMed

    Wu, Yingchun; Wu, Xuecheng; Yao, Longchao; Gréhan, Gérard; Cen, Kefa

    2015-03-20

    The 3D measurement of the particles in a gas-solid pipe flow is of great interest, but remains challenging due to curved pipe walls in various engineering applications. Because of the astigmatism induced by the pipe, concentric ellipse fringes in the hologram of spherical particles are observed in the experiments. With a theoretical analysis of the particle holography by an ABCD matrix, the in-focus particle image can be reconstructed by the modified convolution method and fractional Fourier transform. Thereafter, the particle size, 3D position, and velocity are simultaneously measured by digital holographic particle tracking velocimetry (DHPTV). The successful application of DHPTV to the particle size and 3D velocity measurement in a glass pipe's flow can facilitate its 3D diagnostics. PMID:25968543

  11. The structure of Nevada`s Grant Canyon and Bacon Flat oil fields from 3-D seismic data

    SciTech Connect

    Johnson, E.H.; Zwart, D.W.

    1995-06-01

    The 20 million barrel Grant Canyon structure and its satellite feature, the one million barrel Bacon Flat field, are located at the eastern edge of Railroad Valley, Nevada. Utilizing an eleven square mile 3-D seismic survey, we have unraveled the complicated structure of the field area. The seismic data were calibrated to known geology with 21 wells drilled prior to the 1993 3-D survey, and 4 recent wells. The 3-D data cube provided vertical 2-D seismic lines every 60 feet. Horizontal slices of the data cube rendered {open_quotes}map views{close_quotes} of the structural trends. Still, the interpretation of this complex area was difficult, hampered by extreme velocity variations in the valley fill sediments that degraded data resolution and skewed the imaged structures. The Grant Canyon and Bacon Flat reservoirs are shown to be remnants of detached Devonian rocks that rest upon a northwest-trending salient of younger Paleozoic rocks. The Paleozoic rocks that form the salient are truncated to the southeast against the Troy Intrusive. Beneath the salient, the flank of the intrusive dips about 30 degrees northwest. We show Bacon Flat to be an isolated closure northwest of Grant Canyon field. However, on the south flank of the Grant Canyon reservoir, a significant oil accumulation was trapped on the down side of a normal fault, 400 feet low to the oil column of the field. This appears to be anomalous for a carbonate reservoir with extraordinary permeability, but suggests that more oil may be trapped in the area, on the flanks of producing structures.

  12. 3-D velocity structures, seismicity patterns, and their tectonic implications across the Andean Foreland of San Juan Argentina

    NASA Astrophysics Data System (ADS)

    Asmerom, Biniam Beyene

    Three-dimensional velocity structures and seismicity patterns have been studied across the Andean Foreland of San Juan Argentina using data acquired by PANDA deployment. Distinct velocity variations are revealed between Precordillera in the west and Pie de Palo in the east. The low velocity anomaly beneath Precordillera is associated with the presence of thick sedimentary rocks and thick sediment cover of Matagusanos valley. Similarly, the high velocity anomaly east of Eastern Precordillera is correlated with the presence of basement rocks. These anomalies are observed from the station corrections of Joint Hypocentral Determination (JHD) analysis. A northeast trending west dipping high velocity anomaly is imaged beneath the southern half of Pie de Palo. This anomaly represents a Grenvillian suture zone formed when Pie de Palo collided with the Precordillera. Relocated seismicity using 3-D Vp and Vs models obtained in this study revealed crustal scale buried faults beneath the Eastern Precordillera and Sierra Pie de Palo. The fault defined by the seismicity extend down to a depth of ˜ 40 km and ~35 km beneath Precordillera and Pie de Palo, respectively, defining the lower bound of the brittle to ductile transition of the crust. These results confirm that present day active crustal thickening involves the entire crust in the tectonic process and results in thick-skinned deformation beneath both the Eastern Precordillera and Pie de Palo. Based on the seismicity pattern, geomorphology, and velocity structures, Sierra Pie de Palo, a basement uplift block, can be divided into two separate semi-blocks separated by a northeast trending fracture zone. The northern block is characterized by a well-defined west dipping fault and low Vp/Vs ratio particularly at a depth of 12 to 16 km, while the southern block shows a poorly-defined east dipping fault with high Vp/Vs ratio at a depth of 20 to 26 km. Spatial distribution of the well-relocated crustal earthquakes along these

  13. Full-field strain measurements on turbomachinery components using 3D SLDV technology

    NASA Astrophysics Data System (ADS)

    Maguire, Martyn; Sever, Ibrahim

    2016-06-01

    This paper focuses on measurements of 3D Operating Deflection Shapes (ODSs), and subsequently, construction of full-field surface strain maps of a number of turbomachinery components. For this purpose a 3D Scanning Laser Doppler Vibrometer (SLDV) is used. The ODS measurements are performed for a large number of modes and results obtained are compared with the 1-D shapes that are most commonly measured. It is demonstrated that the 3D measurements are a significant improvement over the 1-D case in terms of independent amount of extra information they provide. This is confirmed through comparisons with FE results. Special tests are carried out to recover the full-field strain on scanned faces of the components used. Visual comparison of these measurements with FE counterparts reveal that strain maps can be successfully measured, not only for low frequency modes but also for highly complex high frequency ones. These maps are measured with different levels of input force to assess the linearity of strain results to varying response amplitudes. Lessons learnt and observations made are summarised in concluding remarks and the scope of future work to take this study into the production environment is discussed. This study constitutes a unique comprehensive investigation into full-field strain measurements using real application hardware and a large frequency range.

  14. Progressive attenuation fields: Fast 2D-3D image registration without precomputation

    SciTech Connect

    Rohlfing, Torsten; Russakoff, Daniel B.; Denzler, Joachim; Mori, Kensaku; Maurer, Calvin R. Jr.

    2005-09-15

    Computation of digitally reconstructed radiograph (DRR) images is the rate-limiting step in most current intensity-based algorithms for the registration of three-dimensional (3D) images to two-dimensional (2D) projection images. This paper introduces and evaluates the progressive attenuation field (PAF), which is a new method to speed up DRR computation. A PAF is closely related to an attenuation field (AF). A major difference is that a PAF is constructed on the fly as the registration proceeds; it does not require any precomputation time, nor does it make any prior assumptions of the patient pose or limit the permissible range of patient motion. A PAF effectively acts as a cache memory for projection values once they are computed, rather than as a lookup table for precomputed projections like standard AFs. We use a cylindrical attenuation field parametrization, which is better suited for many medical applications of 2D-3D registration than the usual two-plane parametrization. The computed attenuation values are stored in a hash table for time-efficient storage and access. Using clinical gold-standard spine image data sets from five patients, we demonstrate consistent speedups of intensity-based 2D-3D image registration using PAF DRRs by a factor of 10 over conventional ray casting DRRs with no decrease of registration accuracy or robustness.

  15. Commissioning a small-field biological irradiator using point, 2D, and 3D dosimetry techniques

    PubMed Central

    Newton, Joseph; Oldham, Mark; Thomas, Andrew; Li, Yifan; Adamovics, John; Kirsch, David G.; Das, Shiva

    2011-01-01

    Purpose: To commission a small-field biological irradiator, the XRad225Cx from Precision x-Ray, Inc., for research use. The system produces a 225 kVp x-ray beam and is equipped with collimating cones that produce both square and circular radiation fields ranging in size from 1 to 40 mm. This work incorporates point, 2D, and 3D measurements to determine output factors (OF), percent-depth-dose (PDD) and dose profiles at multiple depths. Methods: Three independent dosimetry systems were used: ion-chambers (a farmer chamber and a micro-ionisation chamber), 2D EBT2 radiochromic film, and a novel 3D dosimetry system (DLOS/PRESAGE®). Reference point dose rates and output factors were determined from in-air ionization chamber measurements for fields down to ∼13 mm using the formalism of TG61. PDD, profiles, and output factors at three separate depths (0, 0.5, and 2 cm), were determined for all field sizes from EBT2 film measurements in solid water. Several film PDD curves required a scaling correction, reflecting the challenge of accurate film alignment in very small fields. PDDs, profiles, and output factors were also determined with the 3D DLOS/PRESAGE® system which generated isotropic 0.2 mm data, in scan times of 20 min. Results: Surface output factors determined by ion-chamber were observed to gradually drop by ∼9% when the field size was reduced from 40 to 13 mm. More dramatic drops were observed for the smallest fields as determined by EBT∼18% and ∼42% for the 2.5 mm and 1 mm fields, respectively. PRESAGE® and film output factors agreed well for fields <20 mm (where 3D data were available) with mean deviation of 2.2% (range 1%–4%). PDD values at 2 cm depth varied from ∼72% for the 40 mm field, down to ∼55% for the 1 mm field. EBT and PRESAGE® PDDs agreed within ∼3% in the typical therapy region (1–4 cm). At deeper depths the EBT curves were slightly steeper (2.5% at 5 cm). These results indicate good overall consistency between ion-chamber, EBT

  16. Commissioning a small-field biological irradiator using point, 2D, and 3D dosimetry techniques

    SciTech Connect

    Newton, Joseph; Oldham, Mark; Thomas, Andrew; Li Yifan; Adamovics, John; Kirsch, David G.; Das, Shiva

    2011-12-15

    Purpose: To commission a small-field biological irradiator, the XRad225Cx from Precision x-Ray, Inc., for research use. The system produces a 225 kVp x-ray beam and is equipped with collimating cones that produce both square and circular radiation fields ranging in size from 1 to 40 mm. This work incorporates point, 2D, and 3D measurements to determine output factors (OF), percent-depth-dose (PDD) and dose profiles at multiple depths. Methods: Three independent dosimetry systems were used: ion-chambers (a farmer chamber and a micro-ionisation chamber), 2D EBT2 radiochromic film, and a novel 3D dosimetry system (DLOS/PRESAGE registered ). Reference point dose rates and output factors were determined from in-air ionization chamber measurements for fields down to {approx}13 mm using the formalism of TG61. PDD, profiles, and output factors at three separate depths (0, 0.5, and 2 cm), were determined for all field sizes from EBT2 film measurements in solid water. Several film PDD curves required a scaling correction, reflecting the challenge of accurate film alignment in very small fields. PDDs, profiles, and output factors were also determined with the 3D DLOS/PRESAGE registered system which generated isotropic 0.2 mm data, in scan times of 20 min. Results: Surface output factors determined by ion-chamber were observed to gradually drop by {approx}9% when the field size was reduced from 40 to 13 mm. More dramatic drops were observed for the smallest fields as determined by EBT{approx}18% and {approx}42% for the 2.5 mm and 1 mm fields, respectively. PRESAGE registered and film output factors agreed well for fields <20 mm (where 3D data were available) with mean deviation of 2.2% (range 1%-4%). PDD values at 2 cm depth varied from {approx}72% for the 40 mm field, down to {approx}55% for the 1 mm field. EBT and PRESAGE registered PDDs agreed within {approx}3% in the typical therapy region (1-4 cm). At deeper depths the EBT curves were slightly steeper (2.5% at 5 cm

  17. 3D-HST WFC3-SELECTED PHOTOMETRIC CATALOGS IN THE FIVE CANDELS/3D-HST FIELDS: PHOTOMETRY, PHOTOMETRIC REDSHIFTS, AND STELLAR MASSES

    SciTech Connect

    Skelton, Rosalind E.; Whitaker, Katherine E.; Momcheva, Ivelina G.; Van Dokkum, Pieter G.; Bezanson, Rachel; Leja, Joel; Nelson, Erica J.; Oesch, Pascal; Brammer, Gabriel B.; Labbé, Ivo; Franx, Marijn; Fumagalli, Mattia; Van der Wel, Arjen; Da Cunha, Elisabete; Maseda, Michael V.; Förster Schreiber, Natascha; Kriek, Mariska; Lundgren, Britt F.; Magee, Daniel; Marchesini, Danilo; and others

    2014-10-01

    The 3D-HST and CANDELS programs have provided WFC3 and ACS spectroscopy and photometry over ≈900 arcmin{sup 2} in five fields: AEGIS, COSMOS, GOODS-North, GOODS-South, and the UKIDSS UDS field. All these fields have a wealth of publicly available imaging data sets in addition to the Hubble Space Telescope (HST) data, which makes it possible to construct the spectral energy distributions (SEDs) of objects over a wide wavelength range. In this paper we describe a photometric analysis of the CANDELS and 3D-HST HST imaging and the ancillary imaging data at wavelengths 0.3-8 μm. Objects were selected in the WFC3 near-IR bands, and their SEDs were determined by carefully taking the effects of the point-spread function in each observation into account. A total of 147 distinct imaging data sets were used in the analysis. The photometry is made available in the form of six catalogs: one for each field, as well as a master catalog containing all objects in the entire survey. We also provide derived data products: photometric redshifts, determined with the EAZY code, and stellar population parameters determined with the FAST code. We make all the imaging data that were used in the analysis available, including our reductions of the WFC3 imaging in all five fields. 3D-HST is a spectroscopic survey with the WFC3 and ACS grisms, and the photometric catalogs presented here constitute a necessary first step in the analysis of these grism data. All the data presented in this paper are available through the 3D-HST Web site (http://3dhst.research.yale.edu)

  18. An approach to 3D magnetic field calculation using numerical and differential algebra methods

    SciTech Connect

    Caspi, S.; Helm, M.; Laslett, L.J.; Brady, V.O.

    1992-07-17

    Motivated by the need for new means for specification and determination of 3D fields that are produced by electromagnetic lens elements in the region interior to coil windings and seeking to obtain techniques that will be convenient for accurate conductor placement and dynamical study of particle motion, we have conveniently gene the representation of a 2D magnetic field to 3D. We have shown that the 3 dimensioal magnetic field components of a multipole magnet in the curl-fire divergence-fire region near the axis r=0 can be derived from one dimensional functions A{sub n}(z) and their derivatives (part 1). In the region interior to coil windings of accelerator magnets the three spatial components of magnet fields can be expressed in terms of harmonic components'' proportional to functions sin (n{theta}) or cos (n{theta}) of the azimuthal angle. The r,z dependence of any such component can then be expressed in terms of powers of r times functions A{sub n}(z) and their derivatives. For twodimensional configurations B{sub z} of course is identically zero, the derivatives of A{sub n}(z) vanish, and the harmonic components of the transverse field then acquire a simple proportionality B{sub r,n} {proportional to} r{sup n-1} sin (n{theta}),B{sub {theta},n} {proportional to} r{sup n-1} cos (n{theta}), whereas in a 3-D configuration the more complex nature of the field gives rise to additional so-called psuedomultipole'' components as judged by additional powers of r required in the development of the field. Computation of the 3-D magnetic field arising at a sequence of field points, as a direct result of a specified current configuration or coil geometry, can be calculated explicitly through use of the Biot-Savart law and from such data the coefficients can then be derived for a general development of the type indicated above. We indicate, discuss, and illustrate two means by which this development may be performed.

  19. A high-resolution 3D seismic velocity model of the 2010 Mw 8.8 Maule, Chile earthquake rupture zone using land & OBS networks

    NASA Astrophysics Data System (ADS)

    Hicks, S. P.; Rietbrock, A.; Ryder, I. M.; Miller, M.; Lee, C.

    2013-12-01

    American forearc that are also expressed in the forearc Bouguer gravity field. One of these (vp ~ 7.5 km/s) is located in the north of the rupture zone and is associated with a region of intense crustal seismicity in the Pichilemu region. Another anomaly (vp ~ 8.0 km/s) lies along the plate interface, close to the nucleation point of the 2010 mainshock. Values of vp/vs appear to be related to aftershock seismicity at both the up- and down-dip limits of the seismogenic zone. We speculate that fluid saturated sediments in the marine forearc (vp/vs > 1.95) act as the up-dip limit to aftershock seismicity, and dehydration of oceanic crust (vp/vs ~ 1.88), starting at 45 km depth, terminates the rupture at the lower end. By defining a new plate interface model for the central Chile megathrust, we show how the structure of the forearc may have influenced nucleation and rupture of the Maule earthquake, and explore the implications for aftershock seismicity and afterslip. Using our new 3D velocity tomography model and the spectral element method, we will generate full waveform simulations for large aftershocks, forming the basis of an adjoint inversion in the near future.

  20. Development of a 3D Potential Field Forward Modelling System in Python

    NASA Astrophysics Data System (ADS)

    Cole, P.

    2012-12-01

    The collection of potential field data has long been a standard part of geophysical exploration. Specifically, airborne magnetic data is collected routinely in any brown-fields area, because of the low cost and fast acquisition rate compared to other geophysical techniques. However, the interpretation of such data can be a daunting task, especially when 3D models are becoming more necessary. The current trend in modelling software is to follow either the modelling of individual profiles, which are then "joined" up into 3D sections, or to model in a full 3D using polygonal based models (Singh and Guptasarma, 2001). Unfortunately, both techniques have disadvantages. When modelling in 2.5D the impact of other profiles is not truly available on your current profile being modelled, and vice versa. The problem is not present in 3D, but 3D polygonal models, while being easy to construct the initial model, are not as easy to make fast changes to. In some cases, the entire model must be recreated from scratch. The ability to easily change a model is the very basis of forward modelling. With this is mind, the objective of the project was to: 1) Develop software which was truly modelling in 3D 2) Create a system which would allow the rapid changing of the 3D model, without the need to recreate the model. The solution was to adopt a voxel based approach, rather than a polygonal approach. The solution for a cube (Blakely 1996) was used to calculate potential field for each voxel. The voxels are then summed over the entire volume. The language used was python, because of its huge capacity for scientific development. It enables full 3D visualisation as well as complex mathematical routines. Some properties worth noting are: 1) Although 200 rows by 200 columns by 200 layers would imply 8 million calculations, in reality, since the calculation for adjacent voxels produces the same result, only 200 calculations are necessary. 2) Changes to susceptibility and density do not affect

  1. 3-D Numerical Modeling of MHD Flows in Variable Magnetic Field

    NASA Astrophysics Data System (ADS)

    Abdullina, K. I.; Bogovalov, S. V.

    3-D numerical simulation of the liquid metal flow affected by the electromagnetic field in the magnetohydrodynamic (MHD) devices is performed. Software package ANSYS has been used for the numerical calculations. The non-stationary problem has been solved taking into account the influence of the metal flow on the electromagnetic field and nonlinear magnetic permeability of the ferromagnetic cores. Simplified calculations with constant magnetic permeability of the ferromagnetic cores have been performed as well. Comparison of these calculations shows that the simulation of the MHD pump can be performed in the linear approximation. The pump performance curve has been derived in this approximation.

  2. 3D structure and conductive thermal field of the Upper Rhine Graben

    NASA Astrophysics Data System (ADS)

    Freymark, Jessica; Sippel, Judith; Scheck-Wenderoth, Magdalena; Bär, Kristian; Stiller, Manfred; Fritsche, Johann-Gerhard; Kracht, Matthias

    2016-04-01

    The Upper Rhine Graben (URG) was formed as part of the European Cenozoic Rift System in a complex extensional setting. At present-day, it has a large socioeconomic relevance as it provides a great potential for geothermal energy production in Germany and France. For the utilisation of this energy resource it is crucial to understand the structure and the observed temperature anomalies in the rift basin. In the framework of the EU-funded "IMAGE" project (Integrated Methods for Advanced Geothermal Exploration), we apply a data-driven numerical modelling approach to quantify the processes and properties controlling the spatial distribution of subsurface temperatures. Typically, reservoir-scale numerical models are developed for predictions on the subsurface hydrothermal conditions and for reducing the risk of drilling non-productive geothermal wells. One major problem related to such models is setting appropriate boundary conditions that define, for instance, how much heat enters the reservoir from greater depths. Therefore, we first build a regional lithospheric-scale 3D structural model, which covers not only the entire URG but also adjacent geological features like the Black Forest and the Vosges Mountains. In particular, we use a multidisciplinary dataset (e.g. well data, seismic reflection data, existing structural models, gravity) to construct the geometries of the sediments, the crust and the lithospheric mantle that control the spatial distribution of thermal conductivity and radiogenic heat production and hence temperatures. By applying a data-based and lithology-dependent parameterisation of this lithospheric-scale 3D structural model and a 3D finite element method, we calculate the steady-state conductive thermal field for the entire region. Available measured temperatures (down to depths of up to 5 km) are considered to validate the 3D thermal model. We present major characteristics of the lithospheric-scale 3D structural model and results of the 3D

  3. Correlations of Surface Deformation and 3D Flow Field in a Compliant Wall Turbulent Channel Flow.

    NASA Astrophysics Data System (ADS)

    Wang, Jin; Zhang, Cao; Katz, Joseph

    2015-11-01

    This study focuses on the correlations between surface deformation and flow features, including velocity, vorticity and pressure, in a turbulent channel flow over a flat, compliant Polydimethylsiloxane (PDMS) wall. The channel centerline velocity is 2.5 m/s, and the friction Reynolds number is 2.3x103. Analysis is based on simultaneous measurements of the time resolved 3D velocity and surface deformation using tomographic PIV and Mach-Zehnder Interferometry. The volumetric pressure distribution is calculated plane by plane by spatially integrating the material acceleration using virtual boundary, omni-directional method. Conditional sampling based on local high/low pressure and deformation events reveals the primary flow structures causing the deformation. High pressure peaks appear at the interface between sweep and ejection, whereas the negative deformations peaks (dent) appear upstream, under the sweeps. The persistent phase lag between flow and deformations are presumably caused by internal damping within the PDMS. Some of the low pressure peaks and strong ejections are located under the head of hairpin vortices, and accordingly, are associated with positive deformation (bump). Others bumps and dents are correlated with some spanwise offset large inclined quasi-streamwise vortices that are not necessarily associated with hairpins. Sponsored by ONR.

  4. Global 3-D Hybrid Simulations of Mars and the Effect of Crustal Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Brecht, S. H.; Ledvina, S. A.; Luhmann, J. G.

    2001-12-01

    Mars is not protected from the solar wind by a strong intrinsic magnetic field. Further, Mars is a very small planet. These two aspects of Mars mean that the solar wind interaction with the planet is both direct and kinetic in behavior. The large gyroradius of the incoming solar wind and the large gyroradius of the pick up ions make the solar wind interaction with Mars very unique. Over the years the authors using a 3-D kinetic hybrid particle code have studied this planet. Mars Global Surveyor has produced many exciting discoveries. Probably the most significant and unexpected was the presence of the crustal magnetic fields on the surface of the planet. The presence of these strong crustal fields suggests that the solar wind interaction with Mars will be altered. In fact, it suggests that the loss rate of pick up ions and the shape of the Martian magnetosphere will be substantially changed. Results will be presented from our latest 3-D hybrid particle code simulations of Mars where models for the crustal magnetic field have been inserted into the simulations. Particular emphasis will be placed on changes to the magnetic field topology and the change in the rate of pick up ions.

  5. A Global 3D P-Velocity Model of the Earth's Crust and Mantle for Improved Event Location

    NASA Astrophysics Data System (ADS)

    Ballard, S.; Young, C. J.; Hipp, J. R.; Chang, M.; Lewis, J.; Begnaud, M. L.; Rowe, C. A.

    2009-12-01

    further refinement takes place around adjusted nodes to form a new model, and the process is repeated until no more improvement can be obtained. We thus produce a smooth, multi-resolution model with node density appropriate to both ray coverage and the velocity gradients required by the data. This scheme is computationally expensive, so we use a Java-based distributed computing framework developed by Sandia National Laboratories (SNL), providing us with 300+ processors having an efficiency of better than 90% for the calculations. We evaluate our model both in terms of travel time residual variance reduction and in location improvement for GT events. For the latter, we use a new multi-threaded version of the SNL-developed LocOO code modified to use 3D velocity models.

  6. A Parallelized 3D Particle-In-Cell Method With Magnetostatic Field Solver And Its Applications

    NASA Astrophysics Data System (ADS)

    Hsu, Kuo-Hsien; Chen, Yen-Sen; Wu, Men-Zan Bill; Wu, Jong-Shinn

    2008-10-01

    A parallelized 3D self-consistent electrostatic particle-in-cell finite element (PIC-FEM) code using an unstructured tetrahedral mesh was developed. For simulating some applications with external permanent magnet set, the distribution of the magnetostatic field usually also need to be considered and determined accurately. In this paper, we will firstly present the development of a 3D magnetostatic field solver with an unstructured mesh for the flexibility of modeling objects with complex geometry. The vector Poisson equation for magnetostatic field is formulated using the Galerkin nodal finite element method and the resulting matrix is solved by parallel conjugate gradient method. A parallel adaptive mesh refinement module is coupled to this solver for better resolution. Completed solver is then verified by simulating a permanent magnet array with results comparable to previous experimental observations and simulations. By taking the advantage of the same unstructured grid format of this solver, the developed PIC-FEM code could directly and easily read the magnetostatic field for particle simulation. In the upcoming conference, magnetron is simulated and presented for demonstrating the capability of this code.

  7. The role of plasma response in divertor footprint modification by 3D fields in NSTX

    NASA Astrophysics Data System (ADS)

    Ahn, Joonwook; Kim, Kimin; Canal, Gustavo; Gan, Kaifu; Gray, Travis; McLean, Adam; Park, Jong-Kyu; Scotti, Filippo

    2015-11-01

    In NSTX, the divertor footprints of both heat and particle fluxes are found to be significantly modified by externally applied 3D magnetic perturbations. Striations on the divertor surface, indicating separatrix splitting and formation of magnetic lobes, are observed for both n = 1 and n = 3 perturbation fields. These striations can lead to localized heating of the divertor plates and to the re-attachment of detached plasmas, both of which have to be avoided in ITER for successful heat flux management. In this work, the role of plasma response on the formation of separatrix splitting has been investigated in the ideal framework by comparing measured heat and particle flux footprints with field line tracing calculations with and without contributions from the plasma response calculated by the ideal code IPEC. Simulations show that, n = 3 fields are slightly shielded by the plasma, with the measured helical pattern of striations in good agreement with the results from the vacuum approximation. The n = 1 fields are, however, significantly amplified by the plasma response, which provides a better agreement with the measurements. Resistive plasma response calculations by M3D-C1 are also in progress and the results will be compared with those from the ideal code IPEC. This work was supported by DoE Contracts: DE-AC05-00OR22725, DE-AC52-07NA27344 and DE-AC02-09CH11466.

  8. The distribution of 3D superconductivity near the second critical field

    NASA Astrophysics Data System (ADS)

    Kachmar, Ayman; Nasrallah, Marwa

    2016-09-01

    We study the minimizers of the Ginzburg–Landau energy functional with a uniform magnetic field in a three dimensional bounded domain. The functional depends on two positive parameters, the Ginzburg–Landau parameter and the intensity of the applied magnetic field, and acts on complex-valued functions and vector fields. We establish a formula for the distribution of the L 2-norm of the minimizing complex-valued function (order parameter). The formula is valid in the regime where the Ginzburg–Landau parameter is large and the applied magnetic field is close to and strictly below the second critical field—the threshold value corresponding to the transition from the superconducting to the normal phase in the bulk of the sample. Earlier results are valid in 2D domains and for the L 4-norm in 3D domains.

  9. 3-D Monarch reservoir modelling as a development tool: West Salym field, Western Siberia, Russia

    SciTech Connect

    Ainsworth, R.B.; Van Kuyk, A.; Van Lieshout, J.

    1996-12-31

    The Salym fields are located in the central part of the West Siberia basin. The basin developed during the Triassic and contains an almost complete stratigraphic succession from the Jurassic to the Quaternary. The main oil reserves in the Salym fields are located in the Lower Cretaceous proprading deltaic complex. The principal reservoir section in the West Salym field is interpreted as marginal marine. Shoreface, mouthbar, fluvial channel and crevasse-splay subenvironments are recognised. Due to this range of depositional environments and average (exploration) well spacing of 5 km, 3-D modelling of depositional geometries is essential to determine the reservoir architecture and reservoir property trends prior to full-scale field development.

  10. 3-D Monarch reservoir modelling as a development tool: West Salym field, Western Siberia, Russia

    SciTech Connect

    Ainsworth, R.B.; Van Kuyk, A.; Van Lieshout, J. )

    1996-01-01

    The Salym fields are located in the central part of the West Siberia basin. The basin developed during the Triassic and contains an almost complete stratigraphic succession from the Jurassic to the Quaternary. The main oil reserves in the Salym fields are located in the Lower Cretaceous proprading deltaic complex. The principal reservoir section in the West Salym field is interpreted as marginal marine. Shoreface, mouthbar, fluvial channel and crevasse-splay subenvironments are recognised. Due to this range of depositional environments and average (exploration) well spacing of 5 km, 3-D modelling of depositional geometries is essential to determine the reservoir architecture and reservoir property trends prior to full-scale field development.

  11. Effects of 3D Toroidally Asymmetric Magnetic Field on Tokamak Magnetic Surfaces

    NASA Astrophysics Data System (ADS)

    Lao, L. L.

    2005-10-01

    The effects of 3D error magnetic field on magnetic surfaces are investigated using the DIII-D internal coils (I-Coils). Slowly rotating n=1 traveling waves at 5 Hz and various amplitudes were applied to systematically perturb the edge surfaces by programming the I-Coil currents. The vertical separatrix location difference between EFIT magnetic reconstructions that assumes toroidal symmetry and Thomson scattering Te measurements responds in phase to the applied perturbed field. The oscillation amplitudes increase with the strength of the applied field but are much smaller than those expected from the applied field alone. The results indicate that plasma response is important. Various plasma response models based on results from the MHD codes MARS and GATO are being developed and compared to the experimental observations. To more accurately evaluate the effects of magnetic measurement errors, a new form of the magnetic uncertainty matrix is also being implemented into EFIT. Details will be presented.

  12. Velocity fields in a collectively migrating epithelium.

    PubMed

    Petitjean, L; Reffay, M; Grasland-Mongrain, E; Poujade, M; Ladoux, B; Buguin, A; Silberzan, P

    2010-05-19

    We report quantitative measurements of the velocity field of collectively migrating cells in a motile epithelium. The migration is triggered by presenting free surface to an initially confluent monolayer by using a microstencil technique that does not damage the cells. To avoid the technical difficulties inherent in the tracking of single cells, the field is mapped using the technique of particle image velocimetry. The main relevant parameters, such as the velocity module, the order parameter, and the velocity correlation function, are then extracted from this cartography. These quantities are dynamically measured on two types of cells (collectively migrating Madin-Darby canine kidney (MDCK) cells and fibroblastlike normal rat kidney (NRK) cells), first as they approach confluence, and then when the geometrical constraints are released. In particular, for MDCK cells filling up the patterns, we observe a sharp decrease in the average velocity after the point of confluence, whereas the densification of the monolayer is much more regular. After the peeling off of the stencil, a velocity correlation length of approximately 200 microm is measured for MDCK cells versus only approximately 40 microm for the more independent NRK cells. Our conclusions are supported by parallel single-cell tracking experiments. By using the biorthogonal decomposition of the velocity field, we conclude that the velocity field of MDCK cells is very coherent in contrast with the NRK cells. The displacements in the fingers arising from the border of MDCK epithelia are very oriented along their main direction. They influence the velocity field in the epithelium over a distance of approximately 200 microm. PMID:20441742

  13. Massively parallel regularized 3D inversion of potential fields on CPUs and GPUs

    NASA Astrophysics Data System (ADS)

    Čuma, Martin; Zhdanov, Michael S.

    2014-01-01

    We have recently introduced a massively parallel regularized 3D inversion of potential fields data. This program takes as an input gravity or magnetic vector, tensor and Total Magnetic Intensity (TMI) measurements and produces 3D volume of density, susceptibility, or three dimensional magnetization vector, the latest also including magnetic remanence information. The code uses combined MPI and OpenMP approach that maps well onto current multiprocessor multicore clusters and exhibits nearly linear strong and weak parallel scaling. It has been used to invert regional to continental size data sets with up to billion cells of the 3D Earth's volume on large clusters for interpretation of large airborne gravity and magnetics surveys. In this paper we explain the features that made this massive parallelization feasible and extend the code to add GPU support in the form of the OpenACC directives. This implementation resulted in up to a 22x speedup as compared to the scalar multithreaded implementation on a 12 core Intel CPU based computer node. Furthermore, we also introduce a mixed single-double precision approach, which allows us to perform most of the calculation at a single floating point number precision while keeping the result as precise as if the double precision had been used. This approach provides an additional 40% speedup on the GPUs, as compared to the pure double precision implementation. It also has about half of the memory footprint of the fully double precision version.

  14. Effects of electromagnetic field frequencies on chondrocytes in 3D cell-printed composite constructs.

    PubMed

    Yi, Hee-Gyeong; Kang, Kyung Shin; Hong, Jung Min; Jang, Jinah; Park, Moon Nyeo; Jeong, Young Hun; Cho, Dong-Woo

    2016-07-01

    In cartilage tissue engineering, electromagnetic field (EMF) therapy has been reported to have a modest effect on promoting cartilage regeneration. However, these studies were conducted using different frequencies of EMF to stimulate chondrocytes. Thus, it is necessary to investigate the effect of EMF frequency on cartilage formation. In addition to the stimulation, a scaffold is required to satisfy the characteristics of cartilage such as its hydrated and dense extracellular matrix, and a mechanical resilience to applied loads. Therefore, we 3D-printed a composite construct composed of a polymeric framework and a chondrocyte-laden hydrogel. Here, we observed frequency-dependent positive and negative effects on chondrogenesis using a 3D cell-printed cartilage tissue. We found that a frequency of 45 Hz promoted gene expression and secretion of extracellular matrix molecules of chondrocytes. In contrast, a frequency of 7.5 Hz suppressed chondrogenic differentiation in vitro. Additionally, the EMF-treated composite constructs prior to implantation showed consistent results with those of in vitro, suggesting that in vitro pre-treatment with different EMF frequencies provides different capabilities for the enhancement of cartilage formation in vivo. This correlation between EMF frequency and 3D-printed chondrocytes suggests the necessity for optimization of EMF parameters when this physical stimulus is applied to engineered cartilage. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1797-1804, 2016. PMID:26991030

  15. Numerical parameter studies of 3D melt flow and interface shape for directional solidification of silicon in a traveling magnetic field

    NASA Astrophysics Data System (ADS)

    Vizman, D.; Dadzis, K.; Friedrich, J.

    2013-10-01

    The role of various growth and process conditions (Lorentz force, temperature gradients in the melt and the crystal, steady-state crystallization velocity) in directional solidification of multicrystalline silicon in a traveling magnetic field is analyzed for a research-scale furnace (melt size of 22×22×11 cm3). The influence on the melt flow pattern, the typical melt flow velocity, the oscillation amplitude of the velocity and the temperature, the shape of the crystallization interface is determined using three-dimensional (3D) numerical calculations with the STHAMAS3D software and a local quasi steady-state model. It was found that both the interface shape and the melt flow are sensitive to the variation of the considered growth and process parameters.

  16. Unified system for 3D holographic displacement and velocity measurements in fluid and solid mechanics: design and construction of the recording camera and interrogation assembly

    NASA Astrophysics Data System (ADS)

    Barnhart, Donald H.; Chan, Victor S. S.; Halliwell, Neil A.; Coupland, Jeremy M.

    1999-10-01

    This paper introduces a new approach to 3D displacement and velocity measurements that unifies the disciplines of holographic interferometry and holographic particle image velocimetry (HPIV). Equally applicable to fluid and solid mechanics, the overall system enables quantitative displacement measurements between two holographically recorded events from either particle or surface scattering sites, working with both pulsed and continuous-wave laser systems. The resulting measurements exhibit an accuracy corresponding to interferometric system, but with a dynamic range found with PIV systems. Most importantly, this paper introduces the novel use of an optical fiber to specify the measurement points, remove optical aberrations of windows, and eliminate directional ambiguity. An optical fiber is used to probe the recorded holographic image space at each 3D measurement point in order to extract the 3D displacement vectors. This fiber system also employs a novel optical image shifting method to eliminate the problem of directional ambiguity. In addition, the reported system uses 3D complex optical correlation rather than 2D real digital correlation. It is therefore a simple matter to directly obtain 3D displacement and velocity measurements at precisely known 3D locations in the object space. By correlating both the amplitude and phase information in the holographic image, this system can measure spatial distributions of displacements even when the presence of severe aberrations preclude the detection of sharp images.

  17. Coupling Magnetic Fields and ALE Hydrodynamics for 3D Simulations of MFCG's

    SciTech Connect

    White, D; Rieben, R; Wallin, B

    2006-09-20

    We review the development of a full 3D multiphysics code for the simulation of explosively driven Magnetic Flux Compression Generators (MFCG) and related pulse power devices. In a typical MFCG the device is seeded with an initial electric current and the device is then detonated. The detonation compresses the magnetic field and amplifies the current. This is a multiphysics problem in that detonation kinetics, electromagnetic diffusion and induction, material deformation, and thermal effects are all important. This is a tightly coupled problem in that the different physical quantities have comparable spatial and temporal variation, and hence should be solved simultaneously on the same computational mesh.

  18. Magnetic field penetration into a 3D ordered Josephson medium and applicability of the bean model

    NASA Astrophysics Data System (ADS)

    Zelikman, M. A.

    2014-11-01

    The results of calculation of penetration of an external magnetic field into a 3D ordered Josephson medium, based on analysis of modification of the configuration in the direction of the decrease in its Gibbs potential, are reported. When the external field slightly exceeds the stability threshold, the Meissner configuration is transformed into a periodic sequence of linear vortices, which are parallel to the boundary of the medium and are located at a certain distance from it. There exists a critical value I C separating two possible regimes of penetration of the external magnetic field into the medium. For I > I C, for any value of the external field, a finite-length boundary current configuration appears, which completely compensates the external field in the bulk of the sample. At the sample boundary, the field decreases with increasing depth almost linearly. The values of the slope of the magnetic field dependence are rational fractions, which remain constant in finite intervals of I. When the value of I exceeds the upper boundary of such an interval, the slope increases and assumes the value of another rational fraction. If, however, I < I C, such a situation takes place only up to a certain value of external field H max. For higher values, the field penetrates into the medium to an infinite depth. These results lead to the conclusion that the Bean assumptions are violated and that Bean's model is inapplicable for analyzing the processes considered here.

  19. The continuous molecular fields approach to building 3D-QSAR models.

    PubMed

    Baskin, Igor I; Zhokhova, Nelly I

    2013-05-01

    The continuous molecular fields (CMF) approach is based on the application of continuous functions for the description of molecular fields instead of finite sets of molecular descriptors (such as interaction energies computed at grid nodes) commonly used for this purpose. These functions can be encapsulated into kernels and combined with kernel-based machine learning algorithms to provide a variety of novel methods for building classification and regression structure-activity models, visualizing chemical datasets and conducting virtual screening. In this article, the CMF approach is applied to building 3D-QSAR models for 8 datasets through the use of five types of molecular fields (the electrostatic, steric, hydrophobic, hydrogen-bond acceptor and donor ones), the linear convolution molecular kernel with the contribution of each atom approximated with a single isotropic Gaussian function, and the kernel ridge regression data analysis technique. It is shown that the CMF approach even in this simplest form provides either comparable or enhanced predictive performance in comparison with state-of-the-art 3D-QSAR methods. PMID:23719959

  20. Noise analysis for near field 3-D FM-CW radar imaging systems

    SciTech Connect

    Sheen, David M.

    2015-06-19

    Near field radar imaging systems are used for several applications including concealed weapon detection in airports and other high-security venues. Despite the near-field operation, phase noise and thermal noise can limit the performance in several ways including reduction in system sensitivity and reduction of image dynamic range. In this paper, the effects of thermal noise, phase noise, and processing gain are analyzed in the context of a near field 3-D FM-CW imaging radar as might be used for concealed weapon detection. In addition to traditional frequency domain analysis, a time-domain simulation is employed to graphically demonstrate the effect of these noise sources on a fast-chirping FM-CW system.

  1. TE/TM alternating direction scheme for wake field calculation in 3D

    NASA Astrophysics Data System (ADS)

    Zagorodnov, Igor; Weiland, Thomas

    2006-03-01

    In the future, accelerators with very short bunches will be used. It demands developing new numerical approaches for long-time calculation of electromagnetic fields in the vicinity of relativistic bunches. The conventional FDTD scheme, used in MAFIA, ABCI and other wake and PIC codes, suffers from numerical grid dispersion and staircase approximation problem. As an effective cure of the dispersion problem, a numerical scheme without dispersion in longitudinal direction can be used as it was shown by Novokhatski et al. [Transition dynamics of the wake fields of ultrashort bunches, TESLA Report 2000-03, DESY, 2000] and Zagorodnov et al. [J. Comput. Phys. 191 (2003) 525]. In this paper, a new economical conservative scheme for short-range wake field calculation in 3D is presented. As numerical examples show, the new scheme is much more accurate on long-time scale than the conventional FDTD approach.

  2. Effect of high magnetic field on a quasi-3D silver dendrite growing system

    NASA Astrophysics Data System (ADS)

    Tang, Fengzhi; Katsuki, Akio; Tanimoto, Yoshifumi

    2006-05-01

    The Ag+/Cu liquid-solid redox reaction was investigated in a vertical and inhomogeneous high magnetic field (up to 15 T). According to a comparison between the morphologies of quasi-3D silver dendrites generated under different magnetic flux densities, the imposition of a high magnetic field strongly affected the aggregation process of the silver dendrites. The present experiment used four kinds of liquid-solid boundaries, which are affected by the reaction direction and solution condition, as bases for the diffusion limited aggregation (DLA)-like dendritic growth of silver deposition. Results are interpreted in terms of convections of the aqueous solution and a tentative quantitative analysis of forces acting on particles arising from the magnetic field. A new force is predicted theoretically and is discussed in detail.

  3. Rotating field mass and velocity analyzer

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

  4. Flow properties along field lines in a 3-D tilted-dipole geometry

    NASA Technical Reports Server (NTRS)

    Pizzo, V. J.

    1995-01-01

    A 3-D MHD simulation of a global, tilted-dipole solar wind flow pattern is analyzed to determine flow properties along individual magnetic field lines. In the model, flow conditions near the Sun are chosen to provide a reasonable match to the interplanetary configuration prevailing during the recent south polar passage by Ulysses, i.e., a streamer belt inclined approximately 30 deg to the solar equator and speeds ranging from 325-800 km/s. Field lines all across the stream pattern are traced from 1 to 10 AU by following the motion of marker particles embedded in the flow. It is found that those field lines threading the core of the interaction region are subject to significant latitudinal and relative longitudinal displacement over this range of heliocentric distance. Thus, observations taken at a fixed latitude in the inner solar system sample, over the course of a solar rotation, field lines which connect to a range of latitudes in the outer heliosphere. Maps of the field line displacements are presented to help visualize these connections. In addition, it is found that depending upon the location relative to the CIR structure, the radial evolution of fluid elements frozen to different field lines can deviate considerably from that of the canonical solar wind. That is, for selected subsets of field lines, large speed changes (not just at shocks) can be experienced; the density variation can be far from 1/r(exp 2), and the magnetic field intensity need not decay monotonically with distance.

  5. Three-dimensional reconstruction of cardiac flows based on multi-planar velocity fields

    NASA Astrophysics Data System (ADS)

    Falahatpisheh, Ahmad; Pedrizzetti, Gianni; Kheradvar, Arash

    2014-11-01

    Measurement of the three-dimensional flow field inside the cardiac chambers has proven to be a challenging task. This is mainly due to the fact that generalized full-volume velocimetry techniques cannot be easily implemented to the heart chambers. In addition, the rapid pace of the events in the heart does not allow for accurate real-time flow measurements in 3D using imaging modalities such as magnetic resonance imaging, which neglects the transient variations of the flow due to averaging of the flow over multiple heartbeats. In order to overcome these current limitations, we introduce a multi-planar velocity reconstruction approach that can characterize 3D incompressible flows based on the reconstruction of 2D velocity fields. Here, two-dimensional, two-component velocity fields acquired on multiple perpendicular planes are reconstructed into a 3D velocity field through Kriging interpolation and by imposing the incompressibility constraint. Subsequently, the scattered experimental data are projected into a divergence-free vector field space using a fractional step approach. We validate the method in exemplary 3D flows, including the Hill's spherical vortex and a numerically simulated flow downstream of a 3D orifice. During the process of validation, different signal-to-noise ratios are introduced to the flow field, and the method's performance is assessed accordingly. The results show that as the signal-to-noise ratio decreases, the corrected velocity field significantly improves. The method is also applied to the experimental flow inside a mock model of the heart's right ventricle. Taking advantage of the periodicity of the flow, multiple 2D velocity fields in multiple perpendicular planes at different locations of the mock model are measured while being phase-locked for the 3D reconstruction. The results suggest the metamorphosis of the original transvalvular vortex, which forms downstream of the inlet valve during the early filling phase of the right

  6. Segmentation of Hypocenters and 3-D Velocity Structure around the Kii Peninsula Revealed by Onshore and Offshore Seismic Observations

    NASA Astrophysics Data System (ADS)

    Akuhara, T.; Mochizuki, K.; Nakahigashi, K.; Yamada, T.; Shinohara, M.; Sakai, S.; Kanazawa, T.; Uehira, K.; Shimizu, H.

    2013-12-01

    The Philippine Sea Plate subducts beneath the Eurasian Plate at a rate of ~4 cm/year along the Nankai Trough, southwest of Japan. Around the Kii Peninsula, the rupture boundary of the historical Tonankai and Nankai large earthquakes is located, and previous researches have revealed along-strike segmentation of hypocenters [Mochizuki et al., 2010], P-wave anisotropy [Ishise et al., 2009], low frequency earthquake (LFE) distribution [e.g., Obara, 2010] and subduction depth of the Philippine Sea (PHS) Plate, or there may exist a split in the PHS Plate [Ide et al., 2010]. To investigate such segmentation, in our previous work we determined 3-D velocity structure and hypocenters using P- and S-wave arrival times of earthquakes recorded by both ocean bottom seismometers (OBSs) that were deployed from 2003 to 2007 and on-land stations [Akuhara et al., 2013]. As a result, it was discovered that Vp/Vs ratio is also segmented within the oceanic crust and at the bottom of the overriding plate, which coincides with the LFE distribution: segment A is located along the Kii Channel, segment B around the western Kii Peninsula, and segment C around the eastern Kii Peninsula. In segment B, Vp/Vs ratio is low within the oceanic crust and LFE cluster characterized by an anomalously small amount of cumulative slip, compared to the other LFE clusters around the Kii Peninsula, is located [Obara, 2010]. The difference of Vp/Vs ratio and LFE activity among segments were interpreted as difference of pore fluid pressure. In fact, similar segmentation can be seen in hypocenters: Segment A with concentrated seismicity in the oceanic mantle, segment B with that in the oceanic crust, and segment C with little seismicity. To derive characteristic patterns of the hypocenters, we conducted a cluster analysis of earthquakes based on waveform similarity represented by cross-correlation coefficients (CCs) [e.g., Cattaneo, 1999], in which we took varying structural site effects among the OBS stations

  7. LDA measurement of the passage flow field in a 3-D airfoil cascade

    NASA Technical Reports Server (NTRS)

    Stauter, R. C.; Fleeter, S.

    1986-01-01

    Three-dimensional internal flow computational models are currently being developed to predict the flow through turbomachinery blade rows. For these codes to be of quantitative value, they must be verified with data obtained in experiments which model the fundamental flow phenomena. In this paper, the complete three-dimensional flow field through a subsonic annular cascade of cambered airfoils is experimentally quantified. In particular, detailed three-dimensional data are obtained to quantify the inlet velocity profile, the cascade passage velocity field, and the exit region flow field. The primary instrumentation for acquiring these data is a single-channel Laser Doppler Anemometer operating in the backscatter mode, with chordwise distributions of airfoil surface static pressure taps also utilized. Appropriate data are correlated with predictions from the MERIDL/TSONIC codes.

  8. Fast and Memory-Efficient Topological Denoising of 2D and 3D Scalar Fields.

    PubMed

    Günther, David; Jacobson, Alec; Reininghaus, Jan; Seidel, Hans-Peter; Sorkine-Hornung, Olga; Weinkauf, Tino

    2014-12-01

    Data acquisition, numerical inaccuracies, and sampling often introduce noise in measurements and simulations. Removing this noise is often necessary for efficient analysis and visualization of this data, yet many denoising techniques change the minima and maxima of a scalar field. For example, the extrema can appear or disappear, spatially move, and change their value. This can lead to wrong interpretations of the data, e.g., when the maximum temperature over an area is falsely reported being a few degrees cooler because the denoising method is unaware of these features. Recently, a topological denoising technique based on a global energy optimization was proposed, which allows the topology-controlled denoising of 2D scalar fields. While this method preserves the minima and maxima, it is constrained by the size of the data. We extend this work to large 2D data and medium-sized 3D data by introducing a novel domain decomposition approach. It allows processing small patches of the domain independently while still avoiding the introduction of new critical points. Furthermore, we propose an iterative refinement of the solution, which decreases the optimization energy compared to the previous approach and therefore gives smoother results that are closer to the input. We illustrate our technique on synthetic and real-world 2D and 3D data sets that highlight potential applications. PMID:26356972

  9. 3D Magnetic Field Configuration of the 2006 December 13 Flare Extrapolated with the Optimization Method

    NASA Astrophysics Data System (ADS)

    Guo, Y.; Ding, M. D.; Wiegelmann, T.; Li, H.

    2008-06-01

    The photospheric vector magnetic field of the active region NOAA 10930 was obtained with the Solar Optical Telescope (SOT) on board the Hinode satellite with a very high spatial resolution (about 0.3''). Observations of the two-ribbon flare on 2006 December 13 in this active region provide us a good sample to study the magnetic field configuration related to the occurrence of the flare. Using the optimization method for nonlinear force-free field (NLFFF) extrapolation proposed by Wheatland et al. and recently developed by Wiegelmann, we derive the three-dimensional (3D) vector magnetic field configuration associated with this flare. The general topology can be described as a highly sheared core field and a quasi-potential envelope arch field. The core field clearly shows some dips supposed to sustain a filament. Free energy release in the flare, calculated by subtracting the energy contained in the NLFFF and the corresponding potential field, is 2.4 × 1031 ergs, which is ~2% of the preflare potential field energy. We also calculate the shear angles, defined as the angles between the NLFFF and potential field, and find that they become larger at some particular sites in the lower atmosphere, while they become significantly smaller in most places, implying that the whole configuration gets closer to the potential field after the flare. The Ca II H line images obtained with the Broadband Filter Imager (BFI) of the SOT and the 1600 Å images with the Transition Region and Coronal Explorer (TRACE) show that the preflare heating occurs mainly in the core field. These results provide evidence in support of the tether-cutting model of solar flares.

  10. 3-D reservoir characterization of the House Creek oil field, Powder River Basin, Wyoming

    USGS Publications Warehouse

    Higley, Debra K.; Pantea, Michael P.; Slatt, Roger M.

    1997-01-01

    This CD-ROM is intended to serve a broad audience. An important purpose is to explain geologic and geochemical factors that control petroleum production from the House Creek Field. This information may serve as an analog for other marine-ridge sandstone reservoirs. The 3-D slide and movie images are tied to explanations and 2-D geologic and geochemical images to visualize geologic structures in three dimensions, explain the geologic significance of porosity/permeability distribution across the sandstone bodies, and tie this to petroleum production characteristics in the oil field. Movies, text, images including scanning electron photomicrographs (SEM), thin-section photomicrographs, and data files can be copied from the CD-ROM for use in external mapping, statistical, and other applications.

  11. 3D-NTT: a versatile integral field spectro-imager for the NTT

    NASA Astrophysics Data System (ADS)

    Marcelin, M.; Amram, P.; Balard, P.; Balkowski, C.; Boissin, O.; Boulesteix, J.; Carignan, C.; Daigle, O.; de Denus Baillargeon, M.-M.; Epinat, B.; Gach, J.-L.; Hernandez, O.; Rigaud, F.; Vallée, P.

    2008-07-01

    The 3D-NTT is a visible integral field spectro-imager offering two modes. A low resolution mode (R ~ 300 to 6 000) with a large field of view Tunable Filter (17'x17') and a high resolution mode (R ~ 10 000 to 40 000) with a scanning Fabry-Perot (7'x7'). It will be operated as a visitor instrument on the NTT from 2009. Two large programmes will be led: "Characterizing the interstellar medium of nearby galaxies with 2D maps of extinction and abundances" (PI M. Marcelin) and "Gas accretion and radiative feedback in the early universe" (PI J. Bland Hawthorn). Both will be mainly based on the Tunable Filter mode. This instrument is being built as a collaborative effort between LAM (Marseille), GEPI (Paris) and LAE (Montreal). The website adress of the instrument is : http://www.astro.umontreal.ca/3DNTT

  12. 3D stochastic inversion of potential field data using structural geologic constraints

    NASA Astrophysics Data System (ADS)

    Shamsipour, Pejman; Schetselaar, Ernst; Bellefleur, Gilles; Marcotte, Denis

    2014-12-01

    We introduce a new method to include structural orientation constraints into potential field inversion using a stochastic framework. The method considers known geological interfaces and planar orientation data such as stratification estimated from seismic surveys or drill hole information. Integrating prior geological information into inversion methods can effectively reduce ambiguity and improve inversion results. The presented approach uses cokriging prediction with derivatives. The method is applied to two synthetic models to demonstrate its suitability for 3D inversion of potential field data. The method is also applied to the inversion of gravity data collected over the Lalor volcanogenic massive sulfide deposit at Snow Lake, Central Manitoba, Canada. The results show that using a structurally-constrained inversion leads to a better-resolved solution.

  13. Parameter modeling for nanopore lonic field effect transistors in 3-D device simulation.

    PubMed

    Park, Jun-Mo; Chun, Honggu; Park, Y Eugene; Park, Byung-Gook; Lee, Jong-Ho

    2014-11-01

    An Ion Field Effect Transistor (IFET) with nanopore structure was modeled in a conventional 3-dimensional (3-D) device simulator to understand current-voltage (I-V) characteristics and underlying physics of the device. Since the nanopore was filled with positive ions (K+) ions due to the negative interface charge on the insulator surface and negative gate bias condition, we could successfully simulate the IFET structure using modified p-type silicon to mimic KCl solution. We used p-type silicon with a doping concentration of 6.022 x 10(16) cm(-3) which has the same concentration of positive carriers (hole) as in 10(-4) M KCl. By controlling gate electric field effect on the mobility, the I-V curves obtained by the parameter modeling matched very well with the measured data. In addition, the decrease of [V(th)] with increasing V(DS) was physically analyzed. PMID:25958494

  14. High resolution 3D P wave velocity structure beneath Tenerife Island (Canary Islands, Spain) based on tomographic inversion of active-source data

    NASA Astrophysics Data System (ADS)

    GarcíA-Yeguas, Araceli; Koulakov, Ivan; IbáñEz, Jesús M.; Rietbrock, A.

    2012-09-01

    We present a high resolution 3 dimensional (3D) P wave velocity model for Tenerife Island, Canaries, covering the top of Teide volcano (3,718 m a.s.l.) down to around 8 km below sea level (b.s.l). The tomographic inversion is based on a large data set of travel times obtained from a 3D active seismic experiment using offshore shots (air guns) recorded at more than 100 onshore seismic stations. The obtained seismic velocity structure is strongly heterogeneous with significant (up to 40%) lateral variations. The main volcanic structure of the Las Cañadas-Teide-Pico Viejo Complex (CTPVC) is characterized by a high P wave velocity body, similar to many other stratovolcanoes. The presence of different high P wave velocity regions inside the CTPVC may be related to the geological and volcanological evolution of the system. The presence of high P wave velocities at the center of the island is interpreted as evidence for a single central volcanic source for the formation of Tenerife. Furthermore, reduced P wave velocities are found in a small confined region in CTPVC and are more likely related to hydrothermal alteration, as indicated by the existence of fumaroles, than to the presence of a magma chamber beneath the system. In the external regions, surrounding CTPVC a few lower P wave velocity regions can be interpreted as fractured zones, hydrothermal alterations, porous materials and thick volcaniclastic deposits.

  15. Analysis of the repeatability of time-lapse 3d vsp multicomponent surveys, delhi field

    NASA Astrophysics Data System (ADS)

    Carvalho, Mariana Fernandes de

    Delhi Field is a producing oil field located in northeastern Louisiana. In order to monitor the CO2 sweep efficiency, time-lapse 3D seismic data have been acquired in this area. Time-lapse studies are increasingly used to evaluate changes in the seismic response induced by the production of hydrocarbons or the injection of water, CO2 or steam into a reservoir. A 4D seismic signal is generated by a combination of production and injection effects within the reservoir as well as non-repeatability effects. In order to get reliable results from time-lapse seismic methods, it is important to distinguish the production and injection effects from the non-repeatability effects in the 4D seismic signal. Repeatability of 4D land seismic data is affected by several factors. The most significant of them are: source and receiver geometry inaccuracies, differences in seismic sources signatures, variations in the immediate near surface and ambient non-repeatable noise. In this project, two 3D multicomponent VSP surveys acquired in Delhi Field were used to quantify the relative contribution of each factor that can affect the repeatability in land seismic data. The factors analyzed in this study were: source and receiver geometry inaccura- cies, variations in the immediate near surface and ambient non-repeatable noise. This study showed that all these factors had a significant impact on the repeatability of the successive multicomponent VSP surveys in Delhi Field. This project also shows the advantages and disadvantages in the use of different repeata- bility metrics, normalized-root-mean-square (NRMS) difference and signal-to-distortion ratio (SDR) attribute, to evaluate the level of seismic repeatability between successive time-lapse seismic surveys. It is observed that NRMS difference is greatly influenced by time-shifts and that SDR attribute combined with the time-shift may give more distinct and representative repeatability information than the NRMS difference.

  16. Holographic display system for dynamic synthesis of 3D light fields with increased space bandwidth product.

    PubMed

    Agour, Mostafa; Falldorf, Claas; Bergmann, Ralf B

    2016-06-27

    We present a new method for the generation of a dynamic wave field with high space bandwidth product (SBP). The dynamic wave field is generated from several wave fields diffracted by a display which comprises multiple spatial light modulators (SLMs) each having a comparably low SBP. In contrast to similar approaches in stereoscopy, we describe how the independently generated wave fields can be coherently superposed. A major benefit of the scheme is that the display system may be extended to provide an even larger display. A compact experimental configuration which is composed of four phase-only SLMs to realize the coherent combination of independent wave fields is presented. Effects of important technical parameters of the display system on the wave field generated across the observation plane are investigated. These effects include, e.g., the tilt of the individual SLM and the gap between the active areas of multiple SLMs. As an example of application, holographic reconstruction of a 3D object with parallax effects is demonstrated. PMID:27410593

  17. Electric fields and field-aligned currents in polar regions of the solar corona: 3-D MHD consideration

    NASA Technical Reports Server (NTRS)

    Pisanko, Yu. V.

    1995-01-01

    The calculation of the solar rotation electro-dynamical effects in the near-the-Sun solar wind seems more convenient from the non-inertial corotating reference frame. This implies some modification of the 3-D MHD equations generally on the base of the General Theory of Relativity. The paper deals with the search of stationary (in corotating non-inertial reference frame) solutions of the modified 3-D MHD equations for the in near-the-Sun high latitude sub-alfvenic solar wind. The solution is obtained requiring electric fields and field-aligned electric currents in the high latitude near-the-Sun solar wind. Various scenario are explored self-consistently via a number of numerical experiments. The analogy with the high latitude Earth's magnetosphere is used for the interpretation of the results. Possible observational manifestations are discussed.

  18. a Multiple Data Set Joint Inversion Global 3d P-Velocity Model of the Earth's Crust and Mantle for Improved Seismic Event Location

    NASA Astrophysics Data System (ADS)

    Ballard, S.; Begnaud, M. L.; Hipp, J. R.; Chael, E. P.; Encarnacao, A.; Maceira, M.; Yang, X.; Young, C. J.; Phillips, W.

    2013-12-01

    SALSA3D is a global 3D P wave velocity model of the Earth's crust and mantle developed specifically to provide seismic event locations that are more accurate and more precise than are locations from 1D and 2.5D models. In this paper, we present the most recent version of our model, for the first time jointly derived from multiple types of data: body wave travel times, surface wave group velocities, and gravity. The latter two are added to provide information in areas with poor body wave coverage, and are down-weighted in areas where body wave coverage is good. To constrain the inversions, we invoked empirical relations among the density, S velocity, and P velocity. We demonstrate the ability of the new SALSA3D model to reduce mislocations and generate statistically robust uncertainty estimates for a large set of realizations derived from a carefully chosen set of globally-distributed ground truth events. We obtain path-dependent travel time prediction uncertainties for our model by computing the full 3D model covariance matrix of our tomographic system and integrating the model slowness variance and covariance along paths of interest. This approach yields very low travel time prediction uncertainties for well-sampled paths through the Earth and higher uncertainties for paths that are poorly represented in the data set used to develop the model. While the calculation of path-dependent prediction uncertainties with this approach is computationally expensive, uncertainties can be pre-computed for a network of stations and stored in 3D lookup tables that can be quickly and efficiently interrogated using GeoTess software.

  19. The evolving velocity field around protostars

    NASA Astrophysics Data System (ADS)

    Brinch, Christian

    2008-10-01

    Using a hydrodynamical simulation of a gravitational collapse and subsequent disk formation, we calculate a time-resolved synthetic data set with a sophisticated molecular excitation and radiation transfer code. These synthetic data consist of a number of molecular gas emission lines that contains information about the density, temperature, and the velocity field. We use this simulated data set to asses how accurately we can extract information about the underlying velocity field from the lines with a simple parameterized velocity model. This model has only two free parameters, the central stellar mass and a geometric angle that describes the ratio of infall to rotation. We find that, by modeling the spectral lines, we can reliably and uniquely describe the underlying velocity field as given by the hydrodynamical simulation and we then assume that by applying the same parameterized model to real data, we can equally well determine the velocity field of observed young stellar objects. We observe two young sources, L1489 IRS in the Taurus star forming region and IRAS2A in NGC-1333. Both sources are observed with single dish telescopes (JCMT, OSO) and with the Submilimeter Array. For L1489~IRS, the interferometric observations reveal a kinematically distinct region on a scale of a few hundred AUs, dominated by rotation, which is still surrounded by some envelope material. Contrary to this, IRAS2A shows no sign of rotation despite the fact that a compact (disk) component is needed in order to interpret the continuum measurements. We do not detect this component in the velocity field and we conclude that IRAS2A is a considerably younger source than L1489 IRS. While this result is based on the gas flow alone, it is entirely consistent with the current classification of IRAS2A as a Class 0 object and L1489~IRS as a Class I object. This thesis also contains a treatment of CO depletion in the disk and envelope. Under certain temperature and density conditions, CO may freeze

  20. Fine resolution 3D temperature fields off Kerguelen from instrumented penguins

    NASA Astrophysics Data System (ADS)

    Charrassin, Jean-Benoît; Park, Young-Hyang; Le Maho, Yvon; Bost, Charles-André

    2004-12-01

    The use of diving animals as autonomous vectors of oceanographic instruments is rapidly increasing, because this approach yields cost-efficient new information and can be used in previously poorly sampled areas. However, methods for analyzing the collected data are still under development. In particular, difficulties may arise from the heterogeneous data distribution linked to animals' behavior. Here we show how raw temperature data collected by penguin-borne loggers were transformed to a regular gridded dataset that provided new information on the local circulation off Kerguelen. A total of 16 king penguins ( Aptenodytes patagonicus) were equipped with satellite-positioning transmitters and with temperature-time-depth recorders (TTDRs) to record dive depth and sea temperature. The penguins' foraging trips recorded during five summers ranged from 140 to 600 km from the colony and 11,000 dives >100 m were recorded. Temperature measurements recorded during diving were used to produce detailed 3D temperature fields of the area (0-200 m). The data treatment included dive location, determination of the vertical profile for each dive, averaging and gridding of those profiles onto 0.1°×0.1° cells, and optimal interpolation in both the horizontal and vertical using an objective analysis. Horizontal fields of temperature at the surface and 100 m are presented, as well as a vertical section along the main foraging direction of the penguins. Compared to conventional temperature databases (Levitus World Ocean Atlas and historical stations available in the area), the 3D temperature fields collected from penguins are extremely finely resolved, by one order finer. Although TTDRs were less accurate than conventional instruments, such a high spatial resolution of penguin-derived data provided unprecedented detailed information on the upper level circulation pattern east of Kerguelen, as well as the iron-enrichment mechanism leading to a high primary production over the Kerguelen

  1. Torque-consistent 3D force balance and optimization of non-resonant fields in tokamaks

    NASA Astrophysics Data System (ADS)

    Park, Jong-Kyu

    2015-11-01

    A non-axisymmetric magnetic perturbation in tokamaks breaks the toroidal symmetry and produces toroidal torque, which is well known as neoclassical toroidal viscosity (NTV) effects. Although NTV torque is second order, it is the first-order change in the pressure anisotropy that drives currents associated with local torques and thereby modifies the field penetration in force balance. The force operator becomes non-Hermitian, but can be directly solved using parallel, toroidal, and radial force balance, leading to a modified Euler-Lagrange equation. The general perturbed equilibrium code (GPEC), which has been successfully developed to solve the modified Euler-Lagrange equation, gives the torque-consistent 3D force balance as well as self-consistent NTV torque. The self-shielding of the torque becomes apparent in the solutions in high β, which was implied in recent MARS-K applications. Furthermore, the full response matrix including the torque in GPEC provides a new and systematic way of optimizing torque and non-resonant fields. Recently the optimization of 3D fields for torque has been actively studied using the stellarator optimizing tools, but the efficiency and accuracy can be greatly improved by directly incorporating the torque response matrix. There are salient features uncovered by response with the torque, as the response can become invisible in amplitudes but only significant in toroidal phase shift. A perturbation in backward helicity is an example, in which NTV can be induced substantially but quietly without measurable response in amplitudes. A number of other GPEC applications will also be discussed, including the multi-mode responses in high- β tokamak plasmas and the new non-axisymmetric control coil (NCC) design in NSTX-U. This work was supported by DOE Contract DE-AC02-09CH11466.

  2. Engineering a 3D microfluidic culture platform for tumor-treating field application

    PubMed Central

    Pavesi, Andrea; Adriani, Giulia; Tay, Andy; Warkiani, Majid Ebrahimi; Yeap, Wei Hseun; Wong, Siew Cheng; Kamm, Roger D.

    2016-01-01

    The limitations of current cancer therapies highlight the urgent need for a more effective therapeutic strategy. One promising approach uses an alternating electric field; however, the mechanisms involved in the disruption of the cancer cell cycle as well as the potential adverse effects on non-cancerous cells must be clarified. In this study, we present a novel microfluidic device with embedded electrodes that enables the application of an alternating electric field therapy to cancer cells in a 3D extracellular matrix. To demonstrate the potential of our system to aid in designing and testing new therapeutic approaches, cancer cells and cancer cell aggregates were cultured individually or co-cultured with endothelial cells. The metastatic potential of the cancer cells was reduced after electric field treatment. Moreover, the proliferation rate of the treated cancer cells was lower compared with that of the untreated cells, whereas the morphologies and proliferative capacities of the endothelial cells were not significantly affected. These results demonstrate that our novel system can be used to rapidly screen the effect of an alternating electric field on cancer and normal cells within an in vivo-like microenvironment with the potential to optimize treatment protocols and evaluate synergies between tumor-treating field treatment and chemotherapy. PMID:27215466

  3. Engineering a 3D microfluidic culture platform for tumor-treating field application.

    PubMed

    Pavesi, Andrea; Adriani, Giulia; Tay, Andy; Warkiani, Majid Ebrahimi; Yeap, Wei Hseun; Wong, Siew Cheng; Kamm, Roger D

    2016-01-01

    The limitations of current cancer therapies highlight the urgent need for a more effective therapeutic strategy. One promising approach uses an alternating electric field; however, the mechanisms involved in the disruption of the cancer cell cycle as well as the potential adverse effects on non-cancerous cells must be clarified. In this study, we present a novel microfluidic device with embedded electrodes that enables the application of an alternating electric field therapy to cancer cells in a 3D extracellular matrix. To demonstrate the potential of our system to aid in designing and testing new therapeutic approaches, cancer cells and cancer cell aggregates were cultured individually or co-cultured with endothelial cells. The metastatic potential of the cancer cells was reduced after electric field treatment. Moreover, the proliferation rate of the treated cancer cells was lower compared with that of the untreated cells, whereas the morphologies and proliferative capacities of the endothelial cells were not significantly affected. These results demonstrate that our novel system can be used to rapidly screen the effect of an alternating electric field on cancer and normal cells within an in vivo-like microenvironment with the potential to optimize treatment protocols and evaluate synergies between tumor-treating field treatment and chemotherapy. PMID:27215466

  4. Engineering a 3D microfluidic culture platform for tumor-treating field application

    NASA Astrophysics Data System (ADS)

    Pavesi, Andrea; Adriani, Giulia; Tay, Andy; Warkiani, Majid Ebrahimi; Yeap, Wei Hseun; Wong, Siew Cheng; Kamm, Roger D.

    2016-05-01

    The limitations of current cancer therapies highlight the urgent need for a more effective therapeutic strategy. One promising approach uses an alternating electric field; however, the mechanisms involved in the disruption of the cancer cell cycle as well as the potential adverse effects on non-cancerous cells must be clarified. In this study, we present a novel microfluidic device with embedded electrodes that enables the application of an alternating electric field therapy to cancer cells in a 3D extracellular matrix. To demonstrate the potential of our system to aid in designing and testing new therapeutic approaches, cancer cells and cancer cell aggregates were cultured individually or co-cultured with endothelial cells. The metastatic potential of the cancer cells was reduced after electric field treatment. Moreover, the proliferation rate of the treated cancer cells was lower compared with that of the untreated cells, whereas the morphologies and proliferative capacities of the endothelial cells were not significantly affected. These results demonstrate that our novel system can be used to rapidly screen the effect of an alternating electric field on cancer and normal cells within an in vivo-like microenvironment with the potential to optimize treatment protocols and evaluate synergies between tumor-treating field treatment and chemotherapy.

  5. 3D stochastic inversion and joint inversion of potential fields for multi scale parameters

    NASA Astrophysics Data System (ADS)

    Shamsipour, Pejman

    In this thesis we present the development of new techniques for the interpretation of potential field (gravity and magnetic data), which are the most widespread economic geophysical methods used for oil and mineral exploration. These new techniques help to address the long-standing issue with the interpretation of potential fields, namely the intrinsic non-uniqueness inversion of these types of data. The thesis takes the form of three papers (four including Appendix), which have been published, or soon to be published, in respected international journals. The purpose of the thesis is to introduce new methods based on 3D stochastical approaches for: 1) Inversion of potential field data (magnetic), 2) Multiscale Inversion using surface and borehole data and 3) Joint inversion of geophysical potential field data. We first present a stochastic inversion method based on a geostatistical approach to recover 3D susceptibility models from magnetic data. The aim of applying geostatistics is to provide quantitative descriptions of natural variables distributed in space or in time and space. We evaluate the uncertainty on the parameter model by using geostatistical unconditional simulations. The realizations are post-conditioned by cokriging to observation data. In order to avoid the natural tendency of the estimated structure to lay near the surface, depth weighting is included in the cokriging system. Then, we introduce algorithm for multiscale inversion, the presented algorithm has the capability of inverting data on multiple supports. The method involves four main steps: i. upscaling of borehole parameters (It could be density or susceptibility) to block parameters, ii. selection of block to use as constraints based on a threshold on kriging variance, iii. inversion of observation data with selected block densities as constraints, and iv. downscaling of inverted parameters to small prisms. Two modes of application are presented: estimation and simulation. Finally, a novel

  6. 3D Coincidence Imaging Disentangles Intense Field Double Detachment of SF6(–).

    PubMed

    Kandhasamy, Durai Murugan; Albeck, Yishai; Jagtap, Krishna; Strasser, Daniel

    2015-07-23

    The efficient intense field double detachment of molecular anions observed in SF6(–) is studied by 3D coincidence imaging of the dissociation products. The dissociation anisotropy and kinetic energy release distributions are determined for the energetically lowest double detachment channel by virtue of disentangling the SF5(+) + F fragmentation products. The observed nearly isotropic dissociation with respect to the linear laser polarization and surprisingly high kinetic energy release events suggest that the dissociation occurs on a highly excited state. Rydberg (SF6(+))* states composed of a highly repulsive dication core and a Rydberg electron are proposed to explain the observed kinetic energy release, accounting also for the efficient production of all possible cationic fragments at equivalent laser intensities. PMID:26098224

  7. Calibration of Panoramic Cameras with Coded Targets and a 3d Calibration Field

    NASA Astrophysics Data System (ADS)

    Tommaselli, A. M. G.; Marcato, J., Jr.; Moraes, M. V. A.; Silva, S. L. A.; Artero, A. O.

    2014-03-01

    The aim of this paper is to present results achieved with a 3D terrestrial calibration field, designed for calibrating digital cameras and omnidirectional sensors. This terrestrial calibration field is composed of 139 ARUCO coded targets. Some experiments were performed using a Nikon D3100 digital camera with 8mm Samyang Bower fisheye lens. The camera was calibrated in this terrestrial test field using a conventional bundle adjustment with the Collinearity and mathematical models specially designed for fisheye lenses. The CMC software (Calibration with Multiple Cameras), developed in-house, was used for the calibration trials. This software was modified to use fisheye models to which the Conrady-Brown distortion equations were added. The target identification and image measurements of its four corners were performed automatically with a public software. Several experiments were performed with 16 images and the results were presented and compared. Besides the calibration of fish-eye cameras, the field was designed for calibration of a catadrioptic system and brief informations on the calibration of this unit will be provided in the paper.

  8. 3D Printed Scintillators For Use in Field Emission Detection and Other Nuclear Physics Experiments

    NASA Astrophysics Data System (ADS)

    Ficenec, Karen

    2015-10-01

    In accelerator cavities, field emission electrons - electrons that get stripped away from the cavity walls due to the high electromagnetic field necessary to accelerate the main beam - are partially accelerated and can crash into the cavity walls, adding to the heat-load of the cryogenic system. Because these field electrons emit gamma rays when bent by the electromagnetic field, a scintillator, if made to fit the cavity enclosure, can detect their presence. Eliminating the waste of subtractive manufacturing techniques and allowing for the production of unique, varied shapes, 3D printing of scintillators may allow for an efficient detection system. UV light is used to start a chemical polymerization process that links the monomers of the liquid resin together into larger, intertwined molecules, forming the solid structure. Each shape requires slightly different calibration of its optimal printing parameters, such as slice thickness and exposure time to UV light. Thus far, calibration parameters have been optimized for cylinders of 20 mm diameter, cones of 30 mm diameter and 30 mm height, rectangular prisms 30 by 40 by 10 mm, and square pyramids 20 mm across. Calibration continues on creating holes in the prints (for optical fibers), as well as shapes with overhangs. Scintill This work was supported in part by the National Science Foundation under Grant No. PHY-1405857.

  9. Terahertz 3D printed diffractive lens matrices for field-effect transistor detector focal plane arrays.

    PubMed

    Szkudlarek, Krzesimir; Sypek, Maciej; Cywiński, Grzegorz; Suszek, Jarosław; Zagrajek, Przemysław; Feduniewicz-Żmuda, Anna; Yahniuk, Ivan; Yatsunenko, Sergey; Nowakowska-Siwińska, Anna; Coquillat, Dominique; But, Dmytro B; Rachoń, Martyna; Węgrzyńska, Karolina; Skierbiszewski, Czesław; Knap, Wojciech

    2016-09-01

    We present the concept, the fabrication processes and the experimental results for materials and optics that can be used for terahertz field-effect transistor detector focal plane arrays. More specifically, we propose 3D printed arrays of a new type - diffractive multi-zone lenses of which the performance is superior to that of previously used mono-zone diffractive or refractive elements and evaluate them with GaN/AlGaN field-effect transistor terahertz detectors. Experiments performed in the 300-GHz atmospheric window show that the lens arrays offer both a good efficiency and good uniformity, and may improve the signal-to-noise ratio of the terahertz field-effect transistor detectors by more than one order of magnitude. In practice, we tested 3 × 12 lens linear arrays with printed circuit board THz detector arrays used in postal security scanners and observed significant signal-to-noise improvements. Our results clearly show that the proposed technology provides a way to produce cost-effective, reproducible, flat optics for large-size field-effect transistor THz-detector focal plane arrays. PMID:27607620

  10. Surface velocity fields from tidal interactions

    NASA Astrophysics Data System (ADS)

    Koenigsberger, Gloria; Moreno, Edmundo; Harrington, David

    2009-09-01

    Binary stars in eccentric orbits are the clearest example of stars whose equatorial rotation velocity is not synchronized with orbital motion. Under these conditions, the surface velocity field is perturbed from its purely rotational nature, thus modifying the shape of the observationally-detectable photospheric absorption lines on a variety of timescales. Absorption lines are used to derive basic stellar parameters and gain a better physical understanding of the star. Although their variability is often interpreted in terms of non-radial pulsation theory, it is important to understand the nature of the surface velocity fields that are induced by the tidal interactions alone, especially under conditions of rapid rotation and large orbital eccentricity, where the perturbations become highly non-linear. We use a time-marching numerical calculation from first principles to model the surface velocity field due to the tidal interaction (Moreno & Koenigsberger 1999; Toledano et al. 2007). This velocity field is then projected along the line-of-sight to the observer to predict the orbital phase-dependent line-profile variability (Moreno et al. 2005). We compare our model results with very high quality observational data of the B-type binary system α Vir (Spica, HD 116658, P = 4d, e = 0.1), whose variability has in the past been modeled in the context of non-radial pulsations (Smith 1985). Our model reproduces the general features of the observations (Harrington et al. 2009). It is interesting to note that because tidal flows are associated with viscous shear energy dissipation, the question arises as to whether the atmospheric structure of an asynchronously rotating binary star may be reliably modeled using techniques that disregard the dynamical effects on the stellar surface of the tidal interactions.

  11. Field calibration of binocular stereo vision based on fast reconstruction of 3D control field

    NASA Astrophysics Data System (ADS)

    Zhang, Haijun; Liu, Changjie; Fu, Luhua; Guo, Yin

    2015-08-01

    Construction of high-speed railway in China has entered a period of rapid growth. To accurately and quickly obtain the dynamic envelope curve of high-speed vehicle is an important guarantee for safe driving. The measuring system is based on binocular stereo vision. Considering the difficulties in field calibration such as environmental changes and time limits, carried out a field calibration method based on fast reconstruction of three-dimensional control field. With the rapid assembly of pre-calibrated three-dimensional control field, whose coordinate accuracy is guaranteed by manufacture accuracy and calibrated by V-STARS, two cameras take a quick shot of it at the same time. The field calibration parameters are then solved by the method combining linear solution with nonlinear optimization. Experimental results showed that the measurement accuracy can reach up to +/- 0.5mm, and more importantly, in the premise of guaranteeing accuracy, the speed of the calibration and the portability of the devices have been improved considerably.

  12. 3D crustal seismic velocity model for the Gulf of Cadiz and adjacent areas (SW Iberia margin) based on seismic reflection and refraction profiles

    NASA Astrophysics Data System (ADS)

    Lozano, Lucía; Cantavella, Juan Vicente; Barco, Jaime; Carranza, Marta; Burforn, Elisa

    2016-04-01

    The Atlantic margin of the SW Iberian Peninsula and northern Morocco has been subject of study during the last 30 years. Many seismic reflection and refraction profiles have been carried out offshore, providing detailed information about the crustal structure of the main seafloor tectonic domains in the region, from the South Portuguese Zone and the Gulf of Cadiz to the Abyssal Plains and the Josephine Seamount. The interest to obtain a detailed and realistic velocity model for this area, integrating the available data from these studies, is clear, mainly to improve real-time earthquake hypocentral location and for tsunami and earthquake early warning. Since currently real-time seismic location tools allow the implementation of 3D velocity models, we aim to generate a full 3D crustal model. For this purpose we have reviewed more than 50 profiles obtained in different seismic surveys, from 1980 to 2008. Data from the most relevant and reliable 2D seismic velocity published profiles were retrieved. We first generated a Moho depth map of the studied area (latitude 32°N - 41°N and longitude 15°W - 5°W) by extracting Moho depths along each digitized profile with a 10 km spacing, and then interpolating this dataset using ordinary kriging method and generating the contour isodepth map. Then, a 3D crustal velocity model has been obtained. Selected vertical sections at different distances along each profile were considered to retrieve P-wave velocity values at each interface in order to reproduce the geometry and the velocity gradient within each layer. A double linear interpolation, both in distance and depth, with sampling rates of 10 km and 1 km respectively, was carried out to generate a (latitude, longitude, depth, velocity) matrix. This database of all the profiles was interpolated to obtain the P-wave velocity distribution map every kilometer of depth. The new 3D velocity model has been integrated in NonLinLoc location program to relocate several representative

  13. 3-D analysis and interpretation of magnetotelluric data from the Aluto-Langano geothermal field, Ethiopia

    NASA Astrophysics Data System (ADS)

    Samrock, F.; Kuvshinov, A.; Bakker, J.; Jackson, A.; Fisseha, S.

    2015-09-01

    The Main Ethiopian Rift Valley encompasses a number of volcanoes, which are known to be actively deforming with reoccurring periods of uplift and setting. One of the regions where temporal changes take place is the Aluto volcanic complex. It hosts a productive geothermal field and the only currently operating geothermal power plant of Ethiopia. We carried out magnetotelluric (MT) measurements in early 2012 in order to identify the source of unrest. Broad-band MT data (0.001-1000 s) have been acquired at 46 sites covering the expanse of the Aluto volcanic complex with an average site spacing of 1 km. Based on this MT data it is possible to map the bulk electrical resistivity of the subsurface down to depths of several kilometres. Resistivity is a crucial geophysical parameter in geothermal exploration as hydrothermal and magmatic reservoirs are typically related to low resistive zones, which can be easily sensed by MT. Thus by mapping the electrical conductivity one can identify and analyse geothermal systems with respect to their temperature, extent and potential for production of energy. 3-D inversions of the observed MT data from Aluto reveal the typical electrical conductivity distribution of a high-enthalpy geothermal system, which is mainly governed by the hydrothermal alteration mineralogy. The recovered 3-D conductivity models provide no evidence for an active deep magmatic system under Aluto. Forward modelling of the tippers rather suggest that occurrence of melt is predominantly at lower crustal depths along an off-axis fault zone a few tens of kilometres west of the central rift axis. The absence of an active magmatic system implies that the deforming source is most likely situated within the shallow hydrothermal system of the Aluto-Langano geothermal field.

  14. 3-D seismic data for field development: Landslide field case study

    SciTech Connect

    Raeuchle, S.K.; Carr, T.R.; Tucker, R.D. )

    1990-05-01

    The Landslide field is located on the extreme southern flank of the San Joaquin basin, approximately 25 mi south of Bakersfield, California. The field, discovered in 1985, has produced in excess 9 million bbl of oil with an estimated ultimate recovery of more than 13 MMBO. The Miocene Stevens sands, which form the reservoir units at Landslide field, are interpreted as a series of constructional submarine fan deposits. Deposition of the fans was controlled by paleotopography with an abrupt updip pinch-out of the sands to the southwest. The three-dimensional seismic data over the field was used to locate the bottom hole of the landslide 22X-30 development well as close to this abrupt updip pinchout as possible in order to maximize oil recovery. A location was selected two traces (330 ft) from the updip pinch-out as mapped on the seismic data. The well was successfully drilled during 1989, encountering 150 ft of net sand with initial production in excess of 1,500 bbl of oil/day. A pressure buildup test indicates the presence of a boundary approximately 200 ft from the well bore. This boundary is interpreted as the updip pinchout of the Stevens sands against the paleohigh. Based on examination of changes in amplitude, the absence or presence of reservoir-quality sand can be mapped across the paleohighs. Application of three-dimensional seismic data, integration with well data, and in particular reconstruction cuts tied closely to existing wells can be used to map the ultimate extent of the field and contribute to efficient development.

  15. Analysis of the 3D magnetic field and its errors for undulators with iron poles

    SciTech Connect

    Ingold, G.; Bahrdt, J.; Gaupp, A.

    1995-12-31

    The attainable field strength and field quality, such as the optical phase error, the electron beam displacement within the undulator and higher order multipoles of the magnetic field, are discussed. These issues are critical to the design and construction of short period undulators for use in short wavelength FEL or for operation in third generation light sources. We discuss two approaches: (i) For superferric undulators the construction of a full length device would rely on the optimum sorting of precision machined undulator segments. Magnetic data on segments with 20 periods (period length 8.80mm) will be presented. (ii) For hybrid undulators the sorting has to be done on individual poles and magnets. For this approach typical error sources such as machining tolerances, magnetization errors of the permanent magnet material and assembly errors are modeled in 3D and compared to induced errors on an existing hybrid undulator segment. In case of undulators having a full length of hundred periods at least five times as many individual parts have to be characterized. This should be done automatically where both the mechanical and magnetic data before and after the assembly of the magnetic structure are recorded in one step. A CNC programmable measuring device suitable for this task will shortly be presented.

  16. An analytical algorithm for 3D magnetic field mapping of a watt balance magnet

    NASA Astrophysics Data System (ADS)

    Fu, Zhuang; Zhang, Zhonghua; Li, Zhengkun; Zhao, Wei; Han, Bing; Lu, Yunfeng; Li, Shisong

    2016-04-01

    A yoke-based permanent magnet, which has been employed in many watt balances at national metrology institutes, is supposed to generate strong and uniform magnetic field in an air gap in the radial direction. However, in reality the fringe effect due to the finite height of the air gap will introduce an undesired vertical magnetic component to the air gap, which should either be measured or modeled towards some optimizations of the watt balance. A recent publication, i.e. Li et al (2015 Metrologia 52 445), presented a full field mapping method, which in theory will supply useful information for profile characterization and misalignment analysis. This article is an additional material of Li et al (2015 Metrologia 52 445), which develops a different analytical algorithm to represent the 3D magnetic field of a watt balance magnet based on only one measurement for the radial magnetic flux density along the vertical direction, B r (z). The new algorithm is based on the electromagnetic nature of the magnet, which has a much better accuracy.

  17. Adaptive multi-GPU Exchange Monte Carlo for the 3D Random Field Ising Model

    NASA Astrophysics Data System (ADS)

    Navarro, Cristóbal A.; Huang, Wei; Deng, Youjin

    2016-08-01

    This work presents an adaptive multi-GPU Exchange Monte Carlo approach for the simulation of the 3D Random Field Ising Model (RFIM). The design is based on a two-level parallelization. The first level, spin-level parallelism, maps the parallel computation as optimal 3D thread-blocks that simulate blocks of spins in shared memory with minimal halo surface, assuming a constant block volume. The second level, replica-level parallelism, uses multi-GPU computation to handle the simulation of an ensemble of replicas. CUDA's concurrent kernel execution feature is used in order to fill the occupancy of each GPU with many replicas, providing a performance boost that is more notorious at the smallest values of L. In addition to the two-level parallel design, the work proposes an adaptive multi-GPU approach that dynamically builds a proper temperature set free of exchange bottlenecks. The strategy is based on mid-point insertions at the temperature gaps where the exchange rate is most compromised. The extra work generated by the insertions is balanced across the GPUs independently of where the mid-point insertions were performed. Performance results show that spin-level performance is approximately two orders of magnitude faster than a single-core CPU version and one order of magnitude faster than a parallel multi-core CPU version running on 16-cores. Multi-GPU performance is highly convenient under a weak scaling setting, reaching up to 99 % efficiency as long as the number of GPUs and L increase together. The combination of the adaptive approach with the parallel multi-GPU design has extended our possibilities of simulation to sizes of L = 32 , 64 for a workstation with two GPUs. Sizes beyond L = 64 can eventually be studied using larger multi-GPU systems.

  18. Test-particle Orbit Simulations in Fields from a Realistic 3D MHD Simulation

    NASA Astrophysics Data System (ADS)

    Decker, R. B.; Opher, M.; Hill, M. E.

    2007-05-01

    Models designed to explore the global structure of the heliosphere have become increasing sophisticated. Incentives to increase and to further explore the predictive capabilities of such models include the entry of the Voyager spacecraft into the foreshock region of the termination shock (TS), Voyager 1 in mid-2002 and Voyager 2 in late 2004, and the crossing of the TS and passage into the heliosheath (HSH) of Voyager 1 in 2004 day 351. Using the electric and magnetic fields generated by a MHD model of a 3D, asymmetric heliosphere [Opher et al., Ap. J. L., 640, 2006], we have developed full-particle and adiabatic-orbit codes to simulate the motion of test particles in the solar wind, TS, and HSH environments. The full-particle orbits are necessary to investigate energetic ion (e.g., anomalous and galactic cosmic ray) motion at the TS and within the heliospheric current sheet that is included in the MHD model. Adiabatic orbits are used to study particle motion in the much larger volume of the HSH where the non-homogeneous model fields produce complex guiding center motions, including mirroring in local field compressions. We will present results from these orbit computations, which are intended to provide an initial, albeit simplified, look at the propagation of high-energy charged particles, in the scatter-free limit, in the best model of the TS/HSH field configurations currently available. We will also display drift paths of high-energy ions in the HSH fields using the guiding center drift equations that are applicable in the limit of diffusive propagation.

  19. A package for 3-D unstructured grid generation, finite-element flow solution and flow field visualization

    NASA Technical Reports Server (NTRS)

    Parikh, Paresh; Pirzadeh, Shahyar; Loehner, Rainald

    1990-01-01

    A set of computer programs for 3-D unstructured grid generation, fluid flow calculations, and flow field visualization was developed. The grid generation program, called VGRID3D, generates grids over complex configurations using the advancing front method. In this method, the point and element generation is accomplished simultaneously, VPLOT3D is an interactive, menudriven pre- and post-processor graphics program for interpolation and display of unstructured grid data. The flow solver, VFLOW3D, is an Euler equation solver based on an explicit, two-step, Taylor-Galerkin algorithm which uses the Flux Corrected Transport (FCT) concept for a wriggle-free solution. Using these programs, increasingly complex 3-D configurations of interest to aerospace community were gridded including a complete Space Transportation System comprised of the space-shuttle orbitor, the solid-rocket boosters, and the external tank. Flow solutions were obtained on various configurations in subsonic, transonic, and supersonic flow regimes.

  20. Construction of Extended 3D Field of Views of the Internal Bladder Wall Surface: A Proof of Concept

    NASA Astrophysics Data System (ADS)

    Ben-Hamadou, Achraf; Daul, Christian; Soussen, Charles

    2016-09-01

    3D extended field of views (FOVs) of the internal bladder wall facilitate lesion diagnosis, patient follow-up and treatment traceability. In this paper, we propose a 3D image mosaicing algorithm guided by 2D cystoscopic video-image registration for obtaining textured FOV mosaics. In this feasibility study, the registration makes use of data from a 3D cystoscope prototype providing, in addition to each small FOV image, some 3D points located on the surface. This proof of concept shows that textured surfaces can be constructed with minimally modified cystoscopes. The potential of the method is demonstrated on numerical and real phantoms reproducing various surface shapes. Pig and human bladder textures are superimposed on phantoms with known shape and dimensions. These data allow for quantitative assessment of the 3D mosaicing algorithm based on the registration of images simulating bladder textures.

  1. Earthquake relocation using a 3D a-priori geological velocity model from the western Alps to Corsica: Implication for seismic hazard

    NASA Astrophysics Data System (ADS)

    Béthoux, Nicole; Theunissen, Thomas; Beslier, Marie-Odile; Font, Yvonne; Thouvenot, François; Dessa, Jean-Xavier; Simon, Soazig; Courrioux, Gabriel; Guillen, Antonio

    2016-02-01

    The region between the inner zones of the Alps and Corsica juxtaposes an overthickened crust to an oceanic domain, which makes difficult to ascertain the focal depth of seismic events using routine location codes and average 1D velocity models. The aim of this article is to show that, even with a rather lose monitoring network, accurate routine locations can be achieved by using realistic 3D modelling and advanced location techniques. Previous earthquake tomography studies cover the whole region with spatial resolutions of several tens of kilometres on land, but they fail to resolve the marine domain due to the absence of station coverage and sparse seismicity. To overcome these limitations, we first construct a 3D a-priori P and S velocity model integrating known geophysical and geological information. Significant progress has been achieved in the 3D numerical modelling of complex geological structures by the development of dedicated softwares (e.g. 3D GeoModeller), capable at once of elaborating a 3D structural model from geological and geophysical constraints and, possibly, of refining it by inversion processes (Calcagno et al., 2008). Then, we build an arrival-time catalogue of 1500 events recorded from 2000 to 2011. Hypocentres are then located in this model using a numerical code based on the maximum intersection method (Font et al., 2004), updated by Theunissen et al. (2012), as well as another 3D location technique, the NonLinLoc software (Lomax and Curtis, 2001). The reduction of arrival-time residuals and uncertainties (dh, dz) with respect to classical 1D locations demonstrates the improved accuracy allowed by our approach and confirms the coherence of the 3D geological model built and used in this study. Our results are also compared with previous works that benefitted from the installation of dense temporary networks surrounding the studied epicentre area. The resulting 3D location catalogue allows us to improve the regional seismic hazard assessment

  2. CFD Simulation of 3D Flow field in a Gas Centrifuge

    SciTech Connect

    Dongjun Jiang; Shi Zeng

    2006-07-01

    A CFD method was used to study the whole flow field in a gas centrifuge. In this paper, the VSM (Vector Splitting Method) of the FVM (Finite Volume Method) was used to solve the 3D Navier-Stokes equations. An implicit second-order upwind scheme was adopted. The numerical simulation was successfully performed on a parallel cluster computer and a convergence result was obtained. The simulation shows that: in the withdrawal chamber, a strong detached shock wave is formed in front of the scoop; as the radial position increases, the shock becomes stronger and the distance to scoop front surface is smaller. An oblique shock forms in the clearance between the scoop and the centrifuge wall; behind the shock-wave, the radially-inward motion of gas is induced because of the imbalance of the pressure gradient and the centrifugal force. In the separation chamber, a countercurrent is introduced. This indicates that CFD method can be used to study the complex three-dimensional flow field of gas centrifuges. (authors)

  3. Observations of 3-D Electric Fields and Waves Associated With Reconnection at the Dayside Magnetopause

    NASA Astrophysics Data System (ADS)

    Wilder, F. D.; Ergun, R.; Goodrich, K.; Malaspina, D.; Eriksson, S.; Stawarz, J. E.; Sturner, A. P.; Holmes, J.; Burch, J. L.; Torbert, R. B.; Phan, T.; Le Contel, O.; Goldman, M. V.; Newman, D. L.; Lindqvist, P. A.; Khotyaintsev, Y. V.; Strangeway, R. J.; Russell, C. T.; Giles, B. L.; Pollock, C. J.

    2015-12-01

    The phenomenon of magnetic reconnection, especially at electron scales, is still poorly understood. One process that warrants further investigation is the role of wave phenomenon in mediating magnetic reconnection. Previous observations have shown the presence of electrostatic solitary waves (ESWs) as well as whistler mode waves near the dayside reconnection site. Additionally, recent simulations have suggested that whistler waves might be generated by electron phase space holes associated with ESWs as they propagate along the magnetic separatrix towards the diffusion region. Other observations have shown ESWs with distinct speeds and time scales, suggesting that different instabilities generate the ESWs. NASA's recently launched Magnetospheric Multiscale (MMS) mission presents a unique opportunity to investigate the roles of wave phenomena, such as ESWs and whistlers, in asymmetric reconnection at the dayside magnetopause. We will present 3-D electric and magnetic field data from magnetopause crossings by MMS during its first dayside science phase. Burst mode wave data and electron distributions from all four spacecraft will be analyzed to investigate the origin of these wave phenomena, as well as their impact on the reconnection electric field.

  4. pynoddy 1.0: an experimental platform for automated 3-D kinematic and potential field modelling

    NASA Astrophysics Data System (ADS)

    Florian Wellmann, J.; Thiele, Sam T.; Lindsay, Mark D.; Jessell, Mark W.

    2016-03-01

    We present a novel methodology for performing experiments with subsurface structural models using a set of flexible and extensible Python modules. We utilize the ability of kinematic modelling techniques to describe major deformational, tectonic, and magmatic events at low computational cost to develop experiments testing the interactions between multiple kinematic events, effect of uncertainty regarding event timing, and kinematic properties. These tests are simple to implement and perform, as they are automated within the Python scripting language, allowing the encapsulation of entire kinematic experiments within high-level class definitions and fully reproducible results. In addition, we provide a link to geophysical potential-field simulations to evaluate the effect of parameter uncertainties on maps of gravity and magnetics. We provide relevant fundamental information on kinematic modelling and our implementation, and showcase the application of our novel methods to investigate the interaction of multiple tectonic events on a pre-defined stratigraphy, the effect of changing kinematic parameters on simulated geophysical potential fields, and the distribution of uncertain areas in a full 3-D kinematic model, based on estimated uncertainties in kinematic input parameters. Additional possibilities for linking kinematic modelling to subsequent process simulations are discussed, as well as additional aspects of future research. Our modules are freely available on github, including documentation and tutorial examples, and we encourage the contribution to this project.

  5. pynoddy 1.0: an experimental platform for automated 3-D kinematic and potential field modelling

    NASA Astrophysics Data System (ADS)

    Wellmann, J. F.; Thiele, S. T.; Lindsay, M. D.; Jessell, M. W.

    2015-11-01

    We present a novel methodology for performing experiments with subsurface structural models using a set of flexible and extensible Python modules. We utilise the ability of kinematic modelling techniques to describe major deformational, tectonic, and magmatic events at low computational cost to develop experiments testing the interactions between multiple kinematic events, effect of uncertainty regarding event timing, and kinematic properties. These tests are simple to implement and perform, as they are automated within the Python scripting language, allowing the encapsulation of entire kinematic experiments within high-level class definitions and fully reproducible results. In addition, we provide a~link to geophysical potential-field simulations to evaluate the effect of parameter uncertainties on maps of gravity and magnetics. We provide relevant fundamental information on kinematic modelling and our implementation, and showcase the application of our novel methods to investigate the interaction of multiple tectonic events on a pre-defined stratigraphy, the effect of changing kinematic parameters on simulated geophysical potential-fields, and the distribution of uncertain areas in a full 3-D kinematic model, based on estimated uncertainties in kinematic input parameters. Additional possibilities for linking kinematic modelling to subsequent process simulations are discussed, as well as additional aspects of future research. Our modules are freely available on github, including documentation and tutorial examples, and we encourage the contribution to this project.

  6. 3D Loops Evolutions (Twists And Expansions) And Magnetic Fields Interactions Studied With SOHO/EIT

    NASA Astrophysics Data System (ADS)

    Portier-Fozzani, Fabrice

    1999-10-01

    I will present some results from my PHD/Thesis. With SOHO/EIT, 3D Technics such as stereovision and "vision by shape" were developped to study coronal structures evolution. To discribe loops morphology, we adapted with M. Aschwanden a torus fit which include twist evolution. On a quick magnetic flux emergence (August 5th 1997), the twist were decreasing while the loop expand. During a long time evolution (July - August 1996), flaring activities were well correlated with sudden decrease in the twist. These 2 results correspond to the evolution expected with the Parker's formula (1977). Magnetic field lines interactions were also analyzed. From multi-wavelengths observations, we had studied some morphological and topological changes which can be interpreted as interactions between open and closed field lines (ie between Coronal Holes and Active Region Loops). Then, relationship between CME/Flares formation and our different instabilities studied were analyzed in the aim to find, in the futur, good criteria concerning space weather.

  7. Experimental pencil beam kernels derivation for 3D dose calculation in flattening filter free modulated fields.

    PubMed

    Azcona, Juan Diego; Barbés, Benigno; Wang, Lilie; Burguete, Javier

    2016-01-01

    This paper presents a method to obtain the pencil-beam kernels that characterize a megavoltage photon beam generated in a flattening filter free (FFF) linear accelerator (linac) by deconvolution from experimental measurements at different depths. The formalism is applied to perform independent dose calculations in modulated fields. In our previous work a formalism was developed for ideal flat fluences exiting the linac's head. That framework could not deal with spatially varying energy fluences, so any deviation from the ideal flat fluence was treated as a perturbation. The present work addresses the necessity of implementing an exact analysis where any spatially varying fluence can be used such as those encountered in FFF beams. A major improvement introduced here is to handle the actual fluence in the deconvolution procedure. We studied the uncertainties associated to the kernel derivation with this method. Several Kodak EDR2 radiographic films were irradiated with a 10 MV FFF photon beam from two linacs from different vendors, at the depths of 5, 10, 15, and 20cm in polystyrene (RW3 water-equivalent phantom, PTW Freiburg, Germany). The irradiation field was a 50mm diameter circular field, collimated with a lead block. The 3D kernel for a FFF beam was obtained by deconvolution using the Hankel transform. A correction on the low dose part of the kernel was performed to reproduce accurately the experimental output factors. Error uncertainty in the kernel derivation procedure was estimated to be within 0.2%. Eighteen modulated fields used clinically in different treatment localizations were irradiated at four measurement depths (total of fifty-four film measurements). Comparison through the gamma-index to their corresponding calculated absolute dose distributions showed a number of passing points (3%, 3mm) mostly above 99%. This new procedure is more reliable and robust than the previous one. Its ability to perform accurate independent dose calculations was

  8. Experimental pencil beam kernels derivation for 3D dose calculation in flattening filter free modulated fields

    NASA Astrophysics Data System (ADS)

    Diego Azcona, Juan; Barbés, Benigno; Wang, Lilie; Burguete, Javier

    2016-01-01

    This paper presents a method to obtain the pencil-beam kernels that characterize a megavoltage photon beam generated in a flattening filter free (FFF) linear accelerator (linac) by deconvolution from experimental measurements at different depths. The formalism is applied to perform independent dose calculations in modulated fields. In our previous work a formalism was developed for ideal flat fluences exiting the linac’s head. That framework could not deal with spatially varying energy fluences, so any deviation from the ideal flat fluence was treated as a perturbation. The present work addresses the necessity of implementing an exact analysis where any spatially varying fluence can be used such as those encountered in FFF beams. A major improvement introduced here is to handle the actual fluence in the deconvolution procedure. We studied the uncertainties associated to the kernel derivation with this method. Several Kodak EDR2 radiographic films were irradiated with a 10 MV FFF photon beam from two linacs from different vendors, at the depths of 5, 10, 15, and 20cm in polystyrene (RW3 water-equivalent phantom, PTW Freiburg, Germany). The irradiation field was a 50mm diameter circular field, collimated with a lead block. The 3D kernel for a FFF beam was obtained by deconvolution using the Hankel transform. A correction on the low dose part of the kernel was performed to reproduce accurately the experimental output factors. Error uncertainty in the kernel derivation procedure was estimated to be within 0.2%. Eighteen modulated fields used clinically in different treatment localizations were irradiated at four measurement depths (total of fifty-four film measurements). Comparison through the gamma-index to their corresponding calculated absolute dose distributions showed a number of passing points (3%, 3mm) mostly above 99%. This new procedure is more reliable and robust than the previous one. Its ability to perform accurate independent dose calculations was

  9. 2D and 3D Shear-Wave Velocity Structure to >1 Km Depth from Ambient and Active Surface Waves: Three "Deep Remi" Case Studies

    NASA Astrophysics Data System (ADS)

    Louie, J. N.; Pancha, A.; Pullammanappallil, S. K.

    2014-12-01

    Refraction microtermor routinely assesses 1D and 2D velocity-depth profiles to shallow depths of approximately 100 m primarily for engineering applications. Estimation of both shallow and deep (>100 m) shear-velocity structure are key elements in the assessment of urban areas for potential earthquake ground shaking, damage, and the calibration of recorded ground motions. Three independent studies investigated the ability of the refraction microtremor technology to image deep velocity structure, to depths exceeding 1 km (Deep ReMi). In the first study, we were able to delineate basin thicknesses of up to 900 m and the deep-basin velocity structure beneath the Reno-area basin. Constraints on lateral velocity changes in 3D as well as on velocity profiles extended down to 1500 m, and show a possible fault offset. This deployment used 30 stand-alone wireless instruments mated to 4.5 Hz geophones, along each of five arrays 2.9 to 5.8 km long. Rayleigh-wave dispersion was clear at frequencies as low as 0.5 Hz using 120 sec ambient urban noise records. The results allowed construction of a 3D velocity model, vetted by agreement with gravity studies. In a second test, a 5.8 km array delimited the southern edge of the Tahoe Basin, with constraints from gravity. There, bedrock depth increased by 250 m in thickness over a distance of 1600 m, with definition of the velocity of the deeper basin sediments. The third study delineated the collapse region of an underground nuclear explosion within a thick sequence of volcanic extrusives, using a shear-wave minivibe in a radial direction, and horizontal geophones. Analysis showed the cavity extends to 620 m depth, with a width of 180 m and a height of 220 m. Our results demonstrate that deep velocity structure can be recovered using ambient noise. This technique offers the ability to define 2D and 3D structural representations essential for seismic hazard evaluation.

  10. Crustal high-velocity anomaly at the East European Craton margin in SE Poland (TESZ) modelled by 3-D seismic tomography of refracted and reflected arrivals

    NASA Astrophysics Data System (ADS)

    Środa, Piotr; Dec, Monika

    2016-04-01

    The area of Trans-European Suture Zone in SE Poland represents a contact of major tectonic units of different consolidation age - from the Precambrian East European Craton, through Palaeozoic West European Platform to Cenozoic Carpathian orogen. The region was built by several phases of crustal accretion, which resulted in a complex collage of tectonic blocks. In 2000, this region was studied by several seismic wide-angle profiles of CELEBRATION 2000 experiment, providing a dense coverage of seismic data in SE Poland and allowing for detailed investigations of the crustal structure and properties in this area. Beneath the marginal part of the EEC, the 2-D modelling of in-line data form several CELEBRATION profiles revealed a prominent high P-wave velocity anomaly in the upper crust, with Vp of 6.7-7.1 km/s, starting at 10-16 km depth (e.g., Środa et al., 2006). Anomalously high velocities are observed in the area located approximately beneath Lublin trough, to the NE of Teisseyre-Tornquist Zone. Based on 3-D tomography of first arrivals of in- and off-line CELEBRATION 2000 recordings (Malinowski et al., 2008), elevated velocities are also reported in the same area and seem to continue to the SW, off the craton margin. Gravimetric modelling also revealed anomalously high density in the same region at similar depths. High seismic velocities and densities are interpreted as indicative for a pronounced mafic intrusion, possibly related to extensional processes at the EEC margin. Previous 3-D models of the high-velocity intrusion were based on first arrivals (crustal refractions) only. In this study, also off-line reflections (not modelled up to now) are used, in order to enlarge the data set and to better constrain the geometry and properties of the velocity anomaly. A code for 3-D joint tomographic inversion of refracted and reflected arrivals, with model parametrization allowing for velocity discontinuities was used (Rawlinson, 2007). With this approach, besides the

  11. An updated GPS velocity field for Canada

    NASA Astrophysics Data System (ADS)

    Craymer, M. R.; Henton, J. A.; Piraszewski, M.; Lapelle, E.

    2011-12-01

    In an effort to improve previous continental-scale GPS velocity fields for North America and Canada in particular, we have reprocessed data from nearly all continuous GPS sites in Canada, the northern portions of the US including Alaska, Greenland as well as a set of global sites used to define the reference frame. In addition, repeated high accuracy campaign surveys of the Canadian Base Network were included. Previous velocity fields were derived from coordinate time series of somewhat inhomogeneous GPS results due to: (1) the use of relative antenna calibrations that did not include satellite antennas or account for the presence of antenna radomes, (2) the use of different reference frames, (3) the use of IGS precise orbits based on these calibrations and reference frames, and (4) the use of different (evolving) versions of GPS processing software and procedures. This reprocessing effort of all previous data since 2000 is based on more consistent and accurate absolute antenna calibrations of both station and satellite antennas, the ITRF2005 reference frame and the latest versions of the Bernese GPS Software and IGS processing procedures with their so-called "repro1" reprocessed orbits. Also, more than four additional years of continuous data and a new CBN survey campaign have been included in this velocity field estimation. Furthermore, we have processed all the continuous data with NRCan's Precise Point Positioning (PPP) software using the same IGS repro1 orbits, precise clocks and absolute antenna calibrations together with the Vienna Mapping Function (VMF1) for the tropospheric model. The PPP software has proven to be highly efficient for processing such large networks and the additional solutions have provided much needed redundancy for some regions. The new time series and velocity results from both the Bernese and PPP solutions are compared with each other and with our previous solution. Comparisons are also made with solutions from other GPS analysis

  12. A 3-D shear velocity model of the southern North America and the Caribbean plates from ambient noise and earthquake tomography

    NASA Astrophysics Data System (ADS)

    Gaite, B.; Villaseñor, A.; Iglesias, A.; Herraiz, M.; Jiménez-Munt, I.

    2014-10-01

    We use group velocities from earthquake tomography together with group and phase velocities from ambient noise tomography (ANT) of Rayleigh-waves to invert for the 3-D shear-wave velocity structure (5-70 km) of the Caribbean (CAR) and southern North American (NAM) plates. The lithospheric model proposed offers a complete image of the crust and uppermost-mantle with imprints of the tectonic evolution. One of the most striking features inferred is the main role of the Ouachita-Marathon-Sonora orogeny front on the crustal seismic structure of NAM plate. A new imaged feature is the low crustal velocities along USA-Mexico border. The model also shows a break of the E-W mantle velocity dichotomy of the NAM and CAR plates beneath the Isthmus of Tehuantepec and Yucatan Block. High upper-mantle velocities along the Mesoamerican Subduction Zone coincide with inactive volcanic areas while the lowest velocities correspond to active volcanic arcs and thin lithospheric mantle regions.

  13. 3-D water vapor field in the atmospheric boundary layer observed with scanning differential absorption lidar

    NASA Astrophysics Data System (ADS)

    Späth, Florian; Behrendt, Andreas; Muppa, Shravan Kumar; Metzendorf, Simon; Riede, Andrea; Wulfmeyer, Volker

    2016-04-01

    High-resolution three-dimensional (3-D) water vapor data of the atmospheric boundary layer (ABL) are required to improve our understanding of land-atmosphere exchange processes. For this purpose, the scanning differential absorption lidar (DIAL) of the University of Hohenheim (UHOH) was developed as well as new analysis tools and visualization methods. The instrument determines 3-D fields of the atmospheric water vapor number density with a temporal resolution of a few seconds and a spatial resolution of up to a few tens of meters. We present three case studies from two field campaigns. In spring 2013, the UHOH DIAL was operated within the scope of the HD(CP)2 Observational Prototype Experiment (HOPE) in western Germany. HD(CP)2 stands for High Definition of Clouds and Precipitation for advancing Climate Prediction and is a German research initiative. Range-height indicator (RHI) scans of the UHOH DIAL show the water vapor heterogeneity within a range of a few kilometers up to an altitude of 2 km and its impact on the formation of clouds at the top of the ABL. The uncertainty of the measured data was assessed for the first time by extending a technique to scanning data, which was formerly applied to vertical time series. Typically, the accuracy of the DIAL measurements is between 0.5 and 0.8 g m-3 (or < 6 %) within the ABL even during daytime. This allows for performing a RHI scan from the surface to an elevation angle of 90° within 10 min. In summer 2014, the UHOH DIAL participated in the Surface Atmosphere Boundary Layer Exchange (SABLE) campaign in southwestern Germany. Conical volume scans were made which reveal multiple water vapor layers in three dimensions. Differences in their heights in different directions can be attributed to different surface elevation. With low-elevation scans in the surface layer, the humidity profiles and gradients can be related to different land cover such as maize, grassland, and forest as well as different surface layer

  14. 3D Photo Mosaicing of Tagiri Shallow Vent Field by an Autonomous Underwater Vehicle

    NASA Astrophysics Data System (ADS)

    Maki, Toshihiro; Kondo, Hayato; Ura, Tamaki; Sakamaki, Takashi; Mizushima, Hayato; Yanagisawa, Masao

    Although underwater visual observation is an ideal method for detailed survey of seafloors, it is currently a costly process that requires the use of Remotely Operated Vehicles (ROVs) or Human Occupied Vehicles (HOVs), and can cover only a limited area. This paper proposes an innovative method to navigate an autonomous underwater vehicle (AUV) to create both 2D and 3D photo mosaics of seafloors with high positioning accuracy without using any vision-based matching. The vehicle finds vertical pole-like acoustic reflectors to use as positioning landmarks using a profiling sonar based on a SLAM (Simultaneous Localization And Mapping) technique. These reflectors can be either artificial or natural objects, and so the method can be applied to shallow vent fields where conventional acoustic positioning is difficult, since bubble plumes can also be used as landmarks as well as artificial reflectors. Path-planning is performed in real-time based on the positions and types of landmarks so as to navigate safely and stably using landmarks of different types (artificial reflector or bubble plume) found at arbitrary times and locations. Terrain tracker switches control reference between depth and altitude from the seafloor based on a local map of hazardous area created in real-time using onboard perceptual sensors, in order to follow rugged terrains at an altitude of 1 to 2 meters, as this range is ideal for visual observation. The method was implemented in the AUV Tri-Dog 1 and experiments were carried out at Tagiri vent field, Kagoshima Bay in Japan. The AUV succeeded in fully autonomous observation for more than 160 minutes to create a photo mosaic with an area larger than 600 square meters, which revealed the spatial distribution of detailed features such as tube-worm colonies, bubble plumes and bacteria mats. A fine bathymetry of the same area was also created using a light-section ranging system mounted on the vehicle. Finally a 3 D representation of the environment was

  15. A Mean Field Analysis of the Exchange Coupling (J) For 2- and 3-D Structured Tetracyanoethylenide (TCNE -)-based Magnets

    SciTech Connect

    McConnell, Amber C.; Fishman, Randy Scott; Miller, Joel S.

    2012-01-01

    Mean field expressions based on the simple Heisenberg model were derived to correlate the inter- and intralayer exchange coupling to the critical temperatures, Tc, for several TCNE (tetracyanoethylene) based magnets with extended 2- and 3-D structure types. These expressions were used to estimate the exchange coupling, J, for 2-D ferrimagnetic [MII(TCNE)(NCMe)2]+ (M = Mn, Fe), 3-D antiferromagnetic MnII(TCNE)[C4(CN)8]1/2, and 3-D ferrimagnetic MnII(TCNE)3/2(I3)1/2. The sign and magnitude of the exchange coupling are in accord with previously reported magnetic data.

  16. ORBXYZ: a 3D single-particle orbit code for following charged-particle trajectories in equilibrium magnetic fields

    SciTech Connect

    Anderson, D.V.; Cohen, R.H.; Ferguson, J.R.; Johnston, B.M.; Sharp, C.B.; Willmann, P.A.

    1981-06-30

    The single particle orbit code, TIBRO, has been modified extensively to improve the interpolation methods used and to allow use of vector potential fields in the simulation of charged particle orbits on a 3D domain. A 3D cubic B-spline algorithm is used to generate spline coefficients used in the interpolation. Smooth and accurate field representations are obtained. When vector potential fields are used, the 3D cubic spline interpolation formula analytically generates the magnetic field used to push the particles. This field has del.BETA = 0 to computer roundoff. When magnetic induction is used the interpolation allows del.BETA does not equal 0, which can lead to significant nonphysical results. Presently the code assumes quadrupole symmetry, but this is not an essential feature of the code and could be easily removed for other applications. Many details pertaining to this code are given on microfiche accompanying this report.

  17. Modification of divertor heat and article flux profiles with applied 3D fields in NSTX H-mode plasmas

    SciTech Connect

    Ahn, Joon-Wook; Canik, John; Soukhanovskii, V. A.; Maingi, Rajesh; Battaglia, D. J.

    2010-04-01

    Externally imposed non-axisymmetric magnetic perurbations are observed to alter divertor heat and particle flux profiles in the National Spherical Torus Experiment (NSTX). The divertor profiles are foud to have a modust level of multiple local peaks, characteristic of strike poimt splitting or the "magnetis lob" structure, even before the application of the 3D fields in some (but not all) NSTX discharges. This is thought to be due to the intrinsic error fields. The applied 3D fields augmented the intrinsic strike point splitting, making the ampliture of local peaks, and valleys larger in the divertor profile and striations at the divertor surface brighter. The measured heat flux profile shows that the radial location and spacing of the strations are qualitativel consistent witth a vacuum field tracing calcultion. 3D field application did not change the peak divertor heat and particle fluxes at the toroidal location of measurement. Spatial characteristics of the observed patterns are also reported in the paper.

  18. Non-Ideal ELM Stability and Non-Axisymmetric Field Penetration Calculations with M3D-C1

    NASA Astrophysics Data System (ADS)

    Ferraro, N. M.; Chu, M. S.; Snyder, P. B.; Jardin, S. C.; Luo, X.

    2009-11-01

    Numerical studies of ELM stability and non-axisymmetric field penetration in diverted DIII-D and NSTX equilibria are presented, with resistive and finite Larmor radius effects included. These results are obtained with the nonlinear two-fluid code M3D-C1, which has recently been extended to allow linear non-axisymmetric calculations. Benchmarks of M3D-C1 with ideal codes ELITE and GATO show good agreement for the linear stability of peeling-ballooning modes in the ideal limit. New calculations of the resistive stability of ideally stable DIII-D equilibria are presented. M3D-C1 has also been used to calculate the linear response to non-axisymmetric external fields; these calculations are benchmarked with Surfmn and MARS-F. New numerical methods implemented in M3D-C1 are presented, including the treatment of boundary conditions with C^1 elements in a non-rectangular mesh.

  19. 3-D Crustal Velocity Structure of Central Idaho/ Eastern Oregon from Joint Inversion of Rayleigh Wave Group and Phase Velocities Derived from Ambient Seismic Noise: Newest Results from the IDOR Project

    NASA Astrophysics Data System (ADS)

    Bremner, P. M.; Panning, M. P.; Russo, R. M.; Mocanu, V. I.; Stanciu, A. C.; Torpey, M. E.; Hongsresawat, S.; VanDecar, J. C.

    2014-12-01

    We present the latest 3-D isotropic crustal velocity model beneath central Idaho and eastern Oregon. We produced the velocity model from vertical component Rayleigh wave group and phase velocity measurements on data from the IDaho/ORegon (IDOR) Passive seismic network, 86 broadband seismic stations, using ambient noise tomography and the methods of Gallego et. al (2010) and Lin et. al (2008). We calculated inter-station group/phase velocities in narrow frequency bands from travel-time measurements of the stacked cross-correlations (bandpass filtered between 2 and 30 seconds), which we used to invert for velocity structure beneath the network. Goals of our work include refining models of crustal structure in the accreted Blue Mountain terranes in the western study area; determining the depth extent of the Salmon River Suture/West Idaho Shear Zone (WISZ), which crosses north-south through the middle of the network; determining the architecture of the Idaho batholith, an extensive largely crustal-derived pluton; and examining the nature of the autochthonous (?) North American crust and lithosphere beneath and east of the batholith. We derived Rayleigh wave group and phase velocity maps for each frequency band using the damped least-squares inversion method of Tarantola (2005), and then jointly inverted for velocity with depth. Moho depths are prescribed in the joint inversions based on receiver functions, also from the IDOR seismic data, and provides a starting crustal velocity model. 3-D checkerboard resolution tests indicate lateral resolution of better than 40 km. Preliminary results show higher S wave velocities in the western study area, and lower velocities in the lower crust on the east side of the network, consistent with Basin-and-Range style extension there. A tabular velocity anomaly juxtaposing higher above lower seismic velocities dips shallow west in the midcrust on the west side of the network.

  20. Noise analysis for near-field 3D FM-CW radar imaging systems

    NASA Astrophysics Data System (ADS)

    Sheen, David M.

    2015-05-01

    Near field radar imaging systems are used for demanding security applications including concealed weapon detection in airports and other high-security venues. Despite the near-field operation, phase noise and thermal noise can limit performance in several ways. Practical imaging systems can employ arrays with low gain antennas and relatively large signal distribution networks that have substantial losses which limit transmit power and increase the effective noise figure of the receiver chain, resulting in substantial thermal noise. Phase noise can also limit system performance. The signal coupled from transmitter to receiver is much larger than expected target signals. Phase noise from this coupled signal can set the system noise floor if the oscillator is too noisy. Frequency modulated continuous wave (FM-CW) radar transceivers used in short range systems are relatively immune to the effects of the coupled phase noise due to range correlation effects. This effect can reduce the phase-noise floor such that it is below the thermal noise floor for moderate performance oscillators. Phase noise is also manifested in the range response around bright targets, and can cause smaller targets to be obscured. Noise in synthetic aperture imaging systems is mitigated by the processing gain of the system. In this paper, the effects of thermal noise, phase noise, and processing gain are analyzed in the context of a near field 3-D FM-CW imaging radar as might be used for concealed weapon detection. In addition to traditional frequency domain analysis, a time-domain simulation is employed to graphically demonstrate the effect of these noise sources on a fast-chirping FM-CW system.

  1. THE VELOCITY FIELD AROUND GROUPS OF GALAXIES

    SciTech Connect

    Hartwick, F. D. A.

    2011-06-15

    A statistical method is presented for determining the velocity field in the immediate vicinity of groups of galaxies using only positional and redshift information with the goal of studying the perturbation of the Hubble flow around groups more distant than the Local Group. The velocities are assumed to obey a Hubble-like expansion law, i.e., V = H{sub exp} R, where the expansion rate H{sub exp} is to be determined. The method is applied to a large, representative group catalog and evidence is found for a sub-Hubble expansion rate within two well-defined radii beyond the virial radii of the groups. This result is consistent with that of Teerikorpi et al. who found a similar expansion law around three nearby groups and extends it to a more representative volume of space.

  2. Axonal Velocity Distributions in Neural Field Equations

    PubMed Central

    Bojak, Ingo; Liley, David T. J.

    2010-01-01

    By modelling the average activity of large neuronal populations, continuum mean field models (MFMs) have become an increasingly important theoretical tool for understanding the emergent activity of cortical tissue. In order to be computationally tractable, long-range propagation of activity in MFMs is often approximated with partial differential equations (PDEs). However, PDE approximations in current use correspond to underlying axonal velocity distributions incompatible with experimental measurements. In order to rectify this deficiency, we here introduce novel propagation PDEs that give rise to smooth unimodal distributions of axonal conduction velocities. We also argue that velocities estimated from fibre diameters in slice and from latency measurements, respectively, relate quite differently to such distributions, a significant point for any phenomenological description. Our PDEs are then successfully fit to fibre diameter data from human corpus callosum and rat subcortical white matter. This allows for the first time to simulate long-range conduction in the mammalian brain with realistic, convenient PDEs. Furthermore, the obtained results suggest that the propagation of activity in rat and human differs significantly beyond mere scaling. The dynamical consequences of our new formulation are investigated in the context of a well known neural field model. On the basis of Turing instability analyses, we conclude that pattern formation is more easily initiated using our more realistic propagator. By increasing characteristic conduction velocities, a smooth transition can occur from self-sustaining bulk oscillations to travelling waves of various wavelengths, which may influence axonal growth during development. Our analytic results are also corroborated numerically using simulations on a large spatial grid. Thus we provide here a comprehensive analysis of empirically constrained activity propagation in the context of MFMs, which will allow more realistic studies

  3. Configuration and Evaluation of a Dual-Doppler 3-D Wind Field System

    NASA Technical Reports Server (NTRS)

    Crawford, Winifred C.

    2014-01-01

    . Because of issues with de-aliasing the WSR velocity field, the AMU did not use data from this radar in this study and only analyzed the 12 February case. Merging the data to create the dual-Doppler analysis involved several steps. The AMU used instructions from the WDSS-II website and discussion forum to determine the correct tools to use for the analysis, and was successful in creating a merged reflectivity field, which was critical to the success of creating a merged velocity field. However, the AMU was unable to create a merged velocity field. The AMU researched the WDSS-II forum for discussions on similar issues, asked questions on the forum, and tested different options and values in the merger tool with no success. Developing a dual-Doppler wind field was the main goal of this task, but that was not accomplished. It could be an issue of not using the correct options or the correct value for the options used, or there could be issues with the radar data. There is a follow-on AMU task to install the operational version of WDSS-II in the NWS MLB office. This will provide more opportunities to try different options and input values in order to create a merged wind field from KMCO and KMLB.

  4. Quantifying the 3D Odorant Concentration Field Used by Actively Tracking Blue Crabs

    NASA Astrophysics Data System (ADS)

    Webster, D. R.; Dickman, B. D.; Jackson, J. L.; Weissburg, M. J.

    2007-11-01

    Blue crabs and other aquatic organisms locate food and mates by tracking turbulent odorant plumes. The odorant concentration fluctuates unpredictably due to turbulent transport, and many characteristics of the fluctuation pattern have been hypothesized as useful cues for orienting to the odorant source. To make a direct linkage between tracking behavior and the odorant concentration signal, we developed a measurement system based the laser induced fluorescence technique to quantify the instantaneous 3D concentration field surrounding actively tracking blue crabs. The data suggest a correlation between upstream walking speed and the concentration of the odorant signal arriving at the antennule chemosensors, which are located near the mouth region. More specifically, we note an increase in upstream walking speed when high concentration bursts arrive at the antennules location. We also test hypotheses regarding the ability of blue crabs to steer relative to the plume centerline based on the signal contrast between the chemosensors located on their leg appendages. These chemosensors are located much closer to the substrate compared to the antennules and are separated by the width of the blue crab. In this case, it appears that blue crabs use the bilateral signal comparison to track along the edge of the plume.

  5. Broadband Near-Field Ground Motion Simulations in 3D Scattering Media

    NASA Astrophysics Data System (ADS)

    Imperatori, Walter; Mai, Martin

    2013-04-01

    The heterogeneous nature of Earth's crust is manifested in the scattering of propagating seismic waves. In recent years, different techniques have been developed to include such phenomenon in broadband ground-motion calculations, either considering scattering as a semi-stochastic or pure stochastic process. In this study, we simulate broadband (0-10 Hz) ground motions using a 3D finite-difference wave propagation solver using several 3D media characterized by Von Karman correlation functions with different correlation lengths and standard deviation values. Our goal is to investigate scattering characteristics and its influence on the seismic wave-field at short and intermediate distances from the source in terms of ground motion parameters. We also examine other relevant scattering-related phenomena, such as the loss of radiation pattern and the directivity breakdown. We first simulate broadband ground motions for a point-source characterized by a classic omega-squared spectrum model. Fault finiteness is then introduced by means of a Haskell-type source model presenting both sub-shear and super-shear rupture speed. Results indicate that scattering plays an important role in ground motion even at short distances from the source, where source effects are thought to be dominating. In particular, peak ground motion parameters can be affected even at relatively low frequencies, implying that earthquake ground-motion simulations should include scattering also for PGV calculations. At the same time, we find a gradual loss of the source signature in the 2-5 Hz frequency range, together with a distortion of the Mach cones in case of super-shear rupture. For more complex source models and truly heterogeneous Earth, these effects may occur even at lower frequencies. Our simulations suggest that Von Karman correlation functions with correlation length between several hundred meters and few kilometers, Hurst exponent around 0.3 and standard deviation in the 5-10% range

  6. Present-day stress field in subduction zones: Insights from 3D viscoelastic models and data

    NASA Astrophysics Data System (ADS)

    Petricca, Patrizio; Carminati, Eugenio

    2016-01-01

    3D viscoelastic FE models were performed to investigate the impact of geometry and kinematics on the lithospheric stress in convergent margins. Generic geometries were designed in order to resemble natural subduction. Our model predictions mirror the results of previous 2D models concerning the effects of lithosphere-mantle relative flow on stress regimes, and allow a better understanding of the lateral variability of the stress field. In particular, in both upper and lower plates, stress axes orientations depend on the adopted geometry and axes rotations occur following the trench shape. Generally stress axes are oriented perpendicular or parallel to the trench, with the exception of the slab lateral tips where rotations occur. Overall compression results in the upper plate when convergence rate is faster than mantle flow rate, suggesting a major role for convergence. In the slab, along-strike tension occurs at intermediate and deeper depths (> 100 km) in case of mantle flow sustaining the sinking lithosphere and slab convex geometry facing mantle flow or in case of opposing mantle flow and slab concave geometry facing mantle flow. Along-strike compression is predicted in case of sustaining mantle flow and concave slabs or in case of opposing mantle flow and convex slabs. The slab stress field is thus controlled by the direction of impact of mantle flow onto the slab and by slab longitudinal curvature. Slab pull produces not only tension in the bending region of subducted plate but also compression where upper and lower plates are coupled. A qualitative comparison between results and data in selected subductions indicates good match for South America, Mariana and Tonga-Kermadec subductions. Discrepancies, as for Sumatra-Java, emerge due to missing geometric (e.g., occurrence of fault systems and local changes in the orientation of plate boundaries) and rheological (e.g., plasticity associated with slab bending, anisotropy) complexities in the models.

  7. Velocity field of isolated turbulent puffs

    NASA Astrophysics Data System (ADS)

    Ghaem-Maghami, E.; Johari, H.

    2010-11-01

    The velocity field of isolated turbulent puffs was measured using the particle image velocimetry technique and was compared with the steady jet flow field. Puffs were generated by injecting air through a 5 mm diameter nozzle into a flow chamber with a weak coflow. Isolated puffs with a Reynolds number of 5000 were examined in the range of 40-75 diameters downstream of the nozzle. The injection time was varied in order to assess the effects of injection volume and equivalent stroke ratio on the puff structure. The results from phase-locked measurements indicate that as the injection volume increased, puffs elongated in the axial direction and became similar to starting jets in the range considered. The largest scaled fluctuating velocities and turbulent shear stress within the puffs were twice the steady jet values. Inspection of the vorticity field revealed the presence of vorticity throughout the puff volume. Entrainment takes place on the portion of the puff closest to the nozzle and the entrainment rate is greater for the puffs with the smaller injection volume. This is consistent with the observations of rapid mixing and combustion of puffs in previous studies.

  8. Calibrating Phase Delay Measurements and Comparison of 3-D Waveform Kernels with and without Near-field Terms

    NASA Astrophysics Data System (ADS)

    Bremner, P. M.; Panning, M. P.

    2012-12-01

    We present the calibration of an automated scheme to properly window the fundamental surface wave mode of an event record. Multi-taper fundamental mode phase delay measurements were made on a synthetic dataset. Measurement errors are reduced when minimal over tone energy is included in the window. The time window is calibrated by simply varying the minimum and maximum surface wave velocities used to determine the beginning and ending window times with source-receiver distance, as opposed to constant velocities. We compare phase delay measurements with and without calibration against measurements made manually. Manual window setting of a small representative subset of event seismograms are used to adjust these minimum and maximum surface wave velocities. The orthogonal 2.5π-prolate spheroidal wave function eigentapers (Slepian tapers) used in multi-taper methods reduce noise biasing, and can provide error estimates in phase delay measurements. Additionally, we examine the effects of excluding near-field terms in the calculation of 3-D finite-frequency waveform kernels for Rayleigh and Love waves on a synthetic dataset. Two methods of kernel calculation based on the single scatterer Born approximation are compared, that of Panning and Nolet (2008) and Zhao and Chevrot (2011). The Panning and Nolet (2008) method calculates the strain Green's tensors for the source-scatterer and scatterer-receiver paths by the summation of asymptotic surface wave modes, which is an inherently far-field approximation. Waveform kernels are then found by convolution (in the time domain) of these strain Green's tensors. The kernels are formulated based on a hexagonal symmetry with an arbitrary orientation. The Zhao and Chevrot (2011) method creates a database of the set of strain Green's tensors for the source-scatterer (two-sided strain Green's tensor) and scatterer-receiver (one-sided strain Green's tensor) paths, and is calculated by normal mode summation. The full-wave waveform

  9. A 3D photographic capsule endoscope system with full field of view

    NASA Astrophysics Data System (ADS)

    Ou-Yang, Mang; Jeng, Wei-De; Lai, Chien-Cheng; Kung, Yi-Chinn; Tao, Kuan-Heng

    2013-09-01

    Current capsule endoscope uses one camera to capture the surface image in the intestine. It can only observe the abnormal point, but cannot know the exact information of this abnormal point. Using two cameras can generate 3D images, but the visual plane changes while capsule endoscope rotates. It causes that two cameras can't capture the images information completely. To solve this question, this research provides a new kind of capsule endoscope to capture 3D images, which is 'A 3D photographic capsule endoscope system'. The system uses three cameras to capture images in real time. The advantage is increasing the viewing range up to 2.99 times respect to the two camera system. The system can accompany 3D monitor provides the exact information of symptom points, helping doctors diagnose the disease.

  10. SERAPIS project - 3D imaging of the Campi Flegrei caldera (southern Italy) : high resolution P-wave velocity tomography

    NASA Astrophysics Data System (ADS)

    Judenherc, S.; Zollo, A.; Auger, E.; Boschi, L.; Satriano, C.; Serapis Working Group

    2003-04-01

    In September 2001, the SERAPIS project was carried out as an extended active seismic survey in the gulfs of Naples and Pozzuoli. A dense array of 60 three-component on-land stations and 72 sea bottom seismographs (OBS) have been deployed to record more than 5000 air gun shots at a spacing of about 125~m. As a preliminary analysis, the first P-arrival times of a the small offset data in the central part of the region has been inverted using the codes of H.M. Benz. The linearized iterative inversion of 38000 arrival times provided a >80% variance reduction with a node spacing of 250m. At the first order, our model shows a 2-layer structure : low velocity volcanic sediments (2.5-3.5km/s) lying on an inclined high velocity limestone platform (>6km/s). The caldera itself is very well identified, the rim is characterized by a 500-1000m upward shift of the velocity isolines. The whole dataset is expected to provide a wider image with the same resolution (250m). It includes the detailed shape of the refractor beneath the caldera as well as its irregularities out of the bay which have been observered in the seismic sections.

  11. SHANK DESIGNS AND SOIL SURFACE TREATMENTS ON 1,3-D EMISSIONS IN A NURSERY FIELD TRIAL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In California, tree and grapevine field nurseries must meet the CDFA requirements for nematode-free planting stock. Telone II (1,3-D) is the only methyl bromide alternative accepted by CDFA’s Nursery Stock Nematode Certification program, but its use is subject to environmental regulations. A field t...

  12. 3-D visualization of ensemble weather forecasts - Part 2: Forecasting warm conveyor belt situations for aircraft-based field campaigns

    NASA Astrophysics Data System (ADS)

    Rautenhaus, M.; Grams, C. M.; Schäfler, A.; Westermann, R.

    2015-02-01

    We present the application of interactive 3-D visualization of ensemble weather predictions to forecasting warm conveyor belt situations during aircraft-based atmospheric research campaigns. Motivated by forecast requirements of the T-NAWDEX-Falcon 2012 campaign, a method to predict 3-D probabilities of the spatial occurrence of warm conveyor belts has been developed. Probabilities are derived from Lagrangian particle trajectories computed on the forecast wind fields of the ECMWF ensemble prediction system. Integration of the method into the 3-D ensemble visualization tool Met.3D, introduced in the first part of this study, facilitates interactive visualization of WCB features and derived probabilities in the context of the ECMWF ensemble forecast. We investigate the sensitivity of the method with respect to trajectory seeding and forecast wind field resolution. Furthermore, we propose a visual analysis method to quantitatively analyse the contribution of ensemble members to a probability region and, thus, to assist the forecaster in interpreting the obtained probabilities. A case study, revisiting a forecast case from T-NAWDEX-Falcon, illustrates the practical application of Met.3D and demonstrates the use of 3-D and uncertainty visualization for weather forecasting and for planning flight routes in the medium forecast range (three to seven days before take-off).

  13. 3D Tomographic Imaging of the Crustal Velocity Structure beneath the Marmara Sea using Air-gun and Earthquake Data

    NASA Astrophysics Data System (ADS)

    Tarancioglu, Adil; Kocaoglu, Argun H.; Ozalaybey, Serdar

    2014-05-01

    The objective of this study is to investigate the local seismicity and obtain a detailed three-dimensional crustal velocity structure beneath the Marmara Sea in an area surrounding the North Anatolian Fault Zone (NAFZ) by tomographic inversion using both controlled-source (air-gun) and earthquake data. The tomographic inversion is carried out by using the local earthquake tomography code SIMUL2000. Two sets of seismological data, collected in 2006 (EOSMARMARA experiment) and 2001 (SEISMARMARA experiment), are re-processed and used in this study. A total of 441 high quality earthquakes and 452 air-gun shots recorded by a total of 53 Ocean Bottom Seismometers (OBS) are selected for the simultaneous inversion for velocity and hypocentral parameters. The OBS location and time-drift errors are identified from air-gun shot records by a grid search method and required corrections are made on the travel time data. The initial (reference) velocity model and earthquake locations required for the three dimensional tomographic inversion are derived from the one-dimensional velocity model obtained by using the VELEST algorithm in which a subset of earthquakes are selected such that phase readings were made by at least five stations and maximum azimuthal gap was 180o. The inversion results are checked for initial model dependence and the effect of damping factor. The reliability of the results is also evaluated in terms of derivative-weighted-sum, resolution-diagonal-elements values and checkerboard tests. The hypocenter locations of the local earthquakes have been remarkably improved by the three-dimensional velocity model obtained from the tomographic inversion. The three-dimensional velocity model shows that the Tekirdag, Central and Cinarcik Basins are characterized generally by lower Vp (3.0 - 3.5 km/s) values and most of the earthquakes across these regions are located at the depths of 10 to 17 km, about 5 km deeper than those obtained from the one-dimensional reference

  14. 3D seismic velocity structure in the rupture area of the 2014 M8.2 Iquique earthquake in Northern Chile

    NASA Astrophysics Data System (ADS)

    Woollam, Jack; Fuenzallida, Amaya; Garth, Tom; Rietbrock, Andreas; Ruiz, Sergio; Tavera, Hernando

    2016-04-01

    Seismic velocity tomography is one of the key tools in Earth sciences to image the physical properties of the subsurface. In recent years significant advances have been made to image the Chilean subductions zone, especially in the area of the 2010 M8.8 Maule earthquake (e.g. Hicks et al., 2014), providing much needed physical constraints for earthquakes source inversions and rupture models. In 2014 the M8.2 Iquique earthquake struck the northern part of the Chilean subduction zone in close proximity to the Peruvian boarder. The pre- and aftershock sequence of this major earthquake was recorded by a densified seismological network in Northern Chile and Southern Peru, which provides an excellent data set to study in depth the 3D velocity structure along the subduction megathrust. Based on an automatic event catalogue of nearly 10,000 events spanning the time period March to May 2014 we selected approximately 450 events for a staggered 3D inversion approach. Events are selected to guarantee an even ray coverage through the inversion volume. We only select events with a minimum GAP of 200 to improve depth estimates and therefore increase resolution in the marine forearc. Additionally, we investigate secondary arrivals between the P- and S-wave arrival to improve depth location. Up to now we have processed about 450 events, from which about 150 with at least 30 P- and S-wave observations have been selected for the subsequent 3D tomography. Overall the data quality is very high, which allows arrival time estimates better than 0.05s on average. We will show results from the 1D, 2D, and preliminary 3D inversions and discuss the results together with the obtained seismicity distribution.

  15. Velocity Field of Isolated Turbulent Puffs

    NASA Astrophysics Data System (ADS)

    Ghaem-Maghami, Elham; Johari, Hamid

    2006-11-01

    The velocity field of isolated turbulent puffs was investigated by the PIV technique. Particular attention was paid to the entrainment pattern of isolated puffs. Puffs were generated by injecting seeded air through a 5 mm diameter nozzle into a flow chamber with a weak co-flow. Puffs with a Reynolds number of 5,000 were examined in the range of 35 -- 75 diameters downstream of the nozzle. The injection time was varied in order to assess the effect of injection volume and impulse on the puff structure. The results indicate that as the injection volume increased, puffs elongated in the axial direction. The largest mean and fluctuating velocities were within the central portion of the puff. The maximum turbulent shear stress within the puff was as much as 2.5 times the steady jet value. The vorticity field showed the presence of vorticity throughout the puff volume. The ratio of volume flow rate at the puff center to the steady jet volume flux at the same location was largest for the smallest injection volume. The majority of entrainment into the puff occurs below the puff center while the puff cap pushes out into surrounding fluid.

  16. The velocity field in MOND cosmology

    NASA Astrophysics Data System (ADS)

    Candlish, G. N.

    2016-08-01

    The recently developed code for N-body/hydrodynamics simulations in Modified Newtonian Dynamics (MOND), known as RAYMOND, is used to investigate the consequences of MOND on structure formation in a cosmological context, with a particular focus on the velocity field. This preliminary study investigates the results obtained with the two formulations of MOND implemented in RAYMOND, as well as considering the effects of changing the choice of MOND interpolation function, and the cosmological evolution of the MOND acceleration scale. The simulations are contrived such that structure forms in a background cosmology that is similar to Λcold dark matter, but with a significantly lower matter content. Given this, and the fact that a fully consistent MOND cosmology is still lacking, we compare our results with a standard ΛCDM simulation, rather than observations. As well as demonstrating the effectiveness of using RAYMOND for cosmological simulations, it is shown that a significant enhancement of the velocity field is likely an unavoidable consequence of the gravitational modification implemented in MOND, and may represent a clear observational signature of such a modification. It is further suggested that such a signal may be clearest in intermediate-density regions such as cluster outskirts and filaments.

  17. The velocity field in MOND cosmology

    NASA Astrophysics Data System (ADS)

    Candlish, G. N.

    2016-08-01

    The recently developed code for N-body/hydrodynamics simulations in Modified Newtonian Dynamics (MOND), known as RAyMOND, is used to investigate the consequences of MOND on structure formation in a cosmological context, with a particular focus on the velocity field. This preliminary study investigates the results obtained with the two formulations of MOND implemented in RAyMOND, as well as considering the effects of changing the choice of MOND interpolation function, and the cosmological evolution of the MOND acceleration scale. The simulations are contrived such that structure forms in a background cosmology that is similar to $\\Lambda$CDM, but with a significantly lower matter content. Given this, and the fact that a fully consistent MOND cosmology is still lacking, we compare our results with a standard $\\Lambda$CDM simulation, rather than observations. As well as demonstrating the effectiveness of using RAyMOND for cosmological simulations, it is shown that a significant enhancement of the velocity field is likely an unavoidable consequence of the gravitational modification implemented in MOND, and may represent a clear observational signature of such a modification. It is further suggested that such a signal may be clearest in intermediate density regions such as cluster outskirts and filaments.

  18. A high resolution 3D velocity model beneath the Tokyo Metropolitan area by MeSO-net

    NASA Astrophysics Data System (ADS)

    Nakagawa, S.; Sakai, S.; Honda, R.; Kimura, H.; Hirata, N.

    2015-12-01

    Beneath the Tokyo metropolitan area, the Philippine Sea Plate (PSP) subducts and causes devastating mega-thrust earthquakes, such as the 1703 Genroku earthquake (M8.0) and the 1923 Kanto earthquake (M7.9). An M7 or greater (M7+) earthquake in this area at present has high potential to produce devastating serious loss of life and property with even greater global economic repercussions. The Central Disaster Management Council of Japan estimates that an M7+ earthquake will cause 23,000 fatalities and 95 trillion yen (about 1 trillion US$) economic loss. We have launched the Special Project for Reducing Vulnerability for Urban Mega Earthquake Disasters in collaboration with scientists, engineers, and social-scientists in nationwide institutions since 2012. We analyze data from the dense seismic array called Metropolitan Seismic Observation network (MeSO-net), which has 296 seismic stations with spacing of 5 km (Sakai and Hirata, 2009; Kasahara et al., 2009). We applied the double-difference tomography method (Zhang and Thurber, 2003) and estimated the velocity structure and the upper boundary of PSP (Nakagawa et al., 2010). The 2011 Tohoku-oki earthquake (M9.0) has activated seismicity also in Kanto region, providing better coverage of ray paths for tomographic analysis. We obtain much higher resolution velocity models from whole dataset observed by MeSO-net between 2008 and 2015. A detailed image of tomograms shows that PSP contacts Pacific plate at a depth of 50 km beneath northern Tokyo bay. A variation of velocity along the oceanic crust suggests dehydration reaction to produce seismicity in a slab, which may related to the M7+ earthquake. Acknowledgement: This study was supported by the Special Project for Reducing Vulnerability for Urban Mega Earthquake Disasters of MEXT, Japan and the Earthquake Research Institute cooperative research program.

  19. Closed formulae to determine the angular velocity of a body-segment based on 3D measurements.

    PubMed

    Kocsis, L; Béda, G

    2001-01-01

    This paper suggests a simple method to determine the global coordinates of the angular velocity and the angular acceleration of a body segment determined by the coordinates of minimum three markers. There are commonly used calculations for the angular quantities basing on the "hypothesis" of planar motion. The usage of approximate methods can result in quantitative and qualitative errors that may completely disort the reality. The method mentioned here is theoretically absolutely correct and can be well used for smoothing noisy data. PMID:11811842

  20. 4-D stratigraphic architecture and 3-D reservoir zonation of the Mirado Formation, Cusiana Field, Colombia

    SciTech Connect

    Fajardo, A.A.; Cross, T.A.

    1996-12-31

    A high-resolution sequence stratigraphic study using 2300 feet of core calibrated with geophysical logs from 14 wells and 1800 measurements of porosity and permeability established the 4-D stratigraphy and 3-D reservoir zonation of the Mirador. Virtually all reservoir-quality facies are through cross-stratified sandstones which occur in channel facies successions in the lower Mirador, but in bay-head delta and estuarine channel facies successions in the upper Mirador. Petrophysical properties and the geometry, continuity and volume of reservoir-quality sandstones change regularly as function of their stratigraphic position. These vertical facies successions reflect increasing accommodation-to-sediment supply (A/S) ratio through each intermediate-term cycle. The upper long-term cycle comprises four intermediate-term, landward-stepping, symmetrical base-level cycles. These cycles consist of estuarine channel, bay-head to bay-fill facies successions. The transition from channel to bay-head to bay-fill facies successions represents an increase in A/S ratio, and the reverse transition indicates a decrease in A/S ratio. Sixteen reservoir zones were defined within the Cusiana field. Reservoirs within the upper and lower long-term cycles are separated by a continuous middle Mirador mudstone which creates two large reservoir divisions. At the second level of zonation, the reservoir compartments and fluid-flow retardants coincide with the intermediate-term stratigraphic cycles. A third level of reservoir compartmentalization follows the distribution of facies successions within the intermediate-term cycles. A strong stratigraphic control on reservoir properties occurs at the three scales of stratigraphic cyclicity. In all cases as A/S ratio increases, porosity and permeability decrease.

  1. 4-D stratigraphic architecture and 3-D reservoir zonation of the Mirado Formation, Cusiana Field, Colombia

    SciTech Connect

    Fajardo, A.A. ); Cross, T.A. )

    1996-01-01

    A high-resolution sequence stratigraphic study using 2300 feet of core calibrated with geophysical logs from 14 wells and 1800 measurements of porosity and permeability established the 4-D stratigraphy and 3-D reservoir zonation of the Mirador. Virtually all reservoir-quality facies are through cross-stratified sandstones which occur in channel facies successions in the lower Mirador, but in bay-head delta and estuarine channel facies successions in the upper Mirador. Petrophysical properties and the geometry, continuity and volume of reservoir-quality sandstones change regularly as function of their stratigraphic position. These vertical facies successions reflect increasing accommodation-to-sediment supply (A/S) ratio through each intermediate-term cycle. The upper long-term cycle comprises four intermediate-term, landward-stepping, symmetrical base-level cycles. These cycles consist of estuarine channel, bay-head to bay-fill facies successions. The transition from channel to bay-head to bay-fill facies successions represents an increase in A/S ratio, and the reverse transition indicates a decrease in A/S ratio. Sixteen reservoir zones were defined within the Cusiana field. Reservoirs within the upper and lower long-term cycles are separated by a continuous middle Mirador mudstone which creates two large reservoir divisions. At the second level of zonation, the reservoir compartments and fluid-flow retardants coincide with the intermediate-term stratigraphic cycles. A third level of reservoir compartmentalization follows the distribution of facies successions within the intermediate-term cycles. A strong stratigraphic control on reservoir properties occurs at the three scales of stratigraphic cyclicity. In all cases as A/S ratio increases, porosity and permeability decrease.

  2. Comparison of Phase-Based 3D Near-Field Source Localization Techniques for UHF RFID.

    PubMed

    Parr, Andreas; Miesen, Robert; Vossiek, Martin

    2016-01-01

    In this paper, we present multiple techniques for phase-based narrowband backscatter tag localization in three-dimensional space with planar antenna arrays or synthetic apertures. Beamformer and MUSIC localization algorithms, known from near-field source localization and direction-of-arrival estimation, are applied to the 3D backscatter scenario and their performance in terms of localization accuracy is evaluated. We discuss the impact of different transceiver modes known from the literature, which evaluate different send and receive antenna path combinations for a single localization, as in multiple input multiple output (MIMO) systems. Furthermore, we propose a new Singledimensional-MIMO (S-MIMO) transceiver mode, which is especially suited for use with mobile robot systems. Monte-Carlo simulations based on a realistic multipath error model ensure spatial correlation of the simulated signals, and serve to critically appraise the accuracies of the different localization approaches. A synthetic uniform rectangular array created by a robotic arm is used to evaluate selected localization techniques. We use an Ultra High Frequency (UHF) Radiofrequency Identification (RFID) setup to compare measurements with the theory and simulation. The results show how a mean localization accuracy of less than 30 cm can be reached in an indoor environment. Further simulations demonstrate how the distance between aperture and tag affects the localization accuracy and how the size and grid spacing of the rectangular array need to be adapted to improve the localization accuracy down to orders of magnitude in the centimeter range, and to maximize array efficiency in terms of localization accuracy per number of elements. PMID:27347976

  3. Comparison of Phase-Based 3D Near-Field Source Localization Techniques for UHF RFID

    PubMed Central

    Parr, Andreas; Miesen, Robert; Vossiek, Martin

    2016-01-01

    In this paper, we present multiple techniques for phase-based narrowband backscatter tag localization in three-dimensional space with planar antenna arrays or synthetic apertures. Beamformer and MUSIC localization algorithms, known from near-field source localization and direction-of-arrival estimation, are applied to the 3D backscatter scenario and their performance in terms of localization accuracy is evaluated. We discuss the impact of different transceiver modes known from the literature, which evaluate different send and receive antenna path combinations for a single localization, as in multiple input multiple output (MIMO) systems. Furthermore, we propose a new Singledimensional-MIMO (S-MIMO) transceiver mode, which is especially suited for use with mobile robot systems. Monte-Carlo simulations based on a realistic multipath error model ensure spatial correlation of the simulated signals, and serve to critically appraise the accuracies of the different localization approaches. A synthetic uniform rectangular array created by a robotic arm is used to evaluate selected localization techniques. We use an Ultra High Frequency (UHF) Radiofrequency Identification (RFID) setup to compare measurements with the theory and simulation. The results show how a mean localization accuracy of less than 30 cm can be reached in an indoor environment. Further simulations demonstrate how the distance between aperture and tag affects the localization accuracy and how the size and grid spacing of the rectangular array need to be adapted to improve the localization accuracy down to orders of magnitude in the centimeter range, and to maximize array efficiency in terms of localization accuracy per number of elements. PMID:27347976

  4. Using Global Plate Velocity Boundary Conditions for Embedded Regional Geodynamic Models: Application to 3-D Modeling of the Early Rifting of the South Atlantic

    NASA Astrophysics Data System (ADS)

    Taramón, Jorge M.; Morgan, Jason P.; Pérez-Gussinyé, Marta

    2016-04-01

    The treatment of far-field boundary conditions is one of the most poorly resolved issues for regional modeling of geodynamic processes. In viscous flow, the choice of far-field boundary conditions often strongly shapes the large-scale structure of a geosimulation. The mantle velocity field along the sidewalls and base of a modeling region is typically much more poorly known than the geometry of past global motions of the surface plates as constrained by global plate motion reconstructions. For regional rifting models it has become routine to apply highly simplified 'plate spreading' or 'uniform rifting' boundary conditions to a 3-D model that limits its ability to simulate the geodynamic evolution of a specific rifted margin. One way researchers are exploring the sensitivity of regional models to uncertain boundary conditions is to use a nested modeling approach in which a global model is used to determine a large-scale flow pattern that is imposed as a constraint along the boundaries of the region to be modeled. Here we explore the utility of a different approach that takes advantage of the ability of finite element models to use unstructured meshes than can embed much higher resolution sub-regions. Here we demonstrate the workflow and code tools that we created to generate this unstructured mesh: solver based on springs, guide-mesh and routines to improve the quality, e.g., closeness to a regular tetrahedron, of the tetrahedral elements of the mesh. Note that the same routines are used to generate a new mesh in the remeshing of a distorted Lagrangian mesh. In our initial project to validate this approach, we create a global spherical shell mesh in which a higher resolution sub-region is created around the nascent South Atlantic Rifting Margin. Global Plate motion BCs and plate boundaries are applied for the time of the onset of rifting, continuing through several 10s of Ma of rifting. Thermal, compositional, and melt-related buoyancy forces are only non

  5. 3D velocity distribution of P- and S-waves in a biotite gneiss, measured in oil as the pressure medium: Comparison with velocity measurements in a multi-anvil pressure apparatus and with texture-based calculated data

    NASA Astrophysics Data System (ADS)

    Lokajíček, T.; Kern, H.; Svitek, T.; Ivankina, T.

    2014-06-01

    Ultrasonic measurements of the 3D velocity distribution of P- and S-waves were performed on a spherical sample of a biotite gneiss from the Outokumpu scientific drill hole. Measurements were done at room temperature and pressures up to 400 and 70 MPa, respectively, in a pressure vessel with oil as a pressure medium. A modified transducer/sample assembly and the installation of a new mechanical system allowed simultaneous measurements of P- and S-wave velocities in 132 independent directions of the sphere on a net in steps of 15°. Proper signals for P- and S-waves could be recorded by coating the sample surface with a high-viscosity shear wave gel and by temporal point contacting of the transmitter and receiver transducers with the sample surface during the measurements. The 3D seismic measurements revealed a strong foliation-related directional dependence (anisotropy) of P- and S-wave velocities, which is confirmed by measurements in a multi-anvil apparatus on a cube-shaped specimen of the same rock. Both experimental approaches show a marked pressure sensitivity of P- and S-wave velocities and velocity anisotropies. With increasing pressure, P- and S-wave velocities increase non-linearly due to progressive closure of micro-cracks. The reverse is true for velocity anisotropy. 3D velocity calculations based on neutron diffraction measurements of crystallographic preferred orientation (CPO) of major minerals show that the intrinsic bulk anisotropy is basically caused by the CPO of biotite constituting about 23 vol.% of the rock. Including the shape of biotite grains and oriented low-aspect ratio microcracks into the modelling increases bulk anisotropy. An important finding from this study is that the measurements on the sample sphere and on the sample cube displayed distinct differences, particularly in shear wave velocities. It is assumed that the differences are due to the different geometries of the samples and the configuration of the transducer-sample assembly

  6. Processing, inversion, and interpretation of 9C-3D seismic data for characterizing the Morrow A sandstone, Postle Field, Oklahoma

    NASA Astrophysics Data System (ADS)

    Singh, Paritosh

    Detection of Morrow A sandstones is a major problem in the exploration of new fields and the characterization of existing fields because they are very thin and laterally discontinuous. The present research shows the advantages of S-wave data in detecting and characterizing the Morrow A sandstone. Full-waveform modeling is done to understand the sandstone signature in P-, PS- and S-wave gathers. The sandstone shows a distinct high-amplitude event in pure S-wave reflections as compared to the weaker P- and PS-wave events. Modeling also helps in understanding the effect of changing sandstone thickness, interbed multiples (generated by shallow high-velocity anhydrite layers) and sidelobe interference effect (due to Morrow shale) at the Morrow A level. Multicomponent data need proper care while processing, especially the S-wave data which are aected by the near-surface complexity. Cross-spread geometry and 3D FK filtering are effective in removing the low-velocity noise trends. The S-wave data obtained after stripping the S-wave splitting in the overburden show improvement for imaging and reservoir property determination. Individual P- and S-wave attributes as well as their combinations have been analyzed to predict the A sandstone thickness. A multi-attribute map and collocated cokriging procedure is used to derive the seismic-guided isopach of the A sandstone. Postle Field is undergoing CO2 flooding and it is important to understand the characteristics of the reservoir for successful flood management. Density can play an important role in finding and monitoring high-quality reservoirs, and to predict reservoir porosity. prestack P- and S-wave AVO inversion and joint P- and S-wave inversion provide density estimates along with the P- and S-impedance for better characterization of the Morrow A sandstone. The research provides a detailed multicomponent processing, inversion and interpretation work flow for reservoir characterization, which can be used for exploration in

  7. The Utility of 3D Left Atrial Volume and Mitral Flow Velocities as Guides for Acute Volume Resuscitation

    PubMed Central

    Santosa, Claudia M.; Rose, David D.; Fleming, Neal W.

    2015-01-01

    Left ventricular end-diastolic pressure (LVEDP) is the foundation of cardiac function assessment. Because of difficulties and risks associated with its direct measurement, correlates of LVEDP derived by pulmonary artery (PA) catheterization or transesophageal echocardiography (TEE) are commonly adopted. TEE has the advantage of being less invasive; however TEE-based estimation of LVEDP using correlates such as left ventricular end-diastolic volume (LVEDV) has technical difficulties that limit its clinical usefulness. Using intraoperative acute normovolemic hemodilution (ANH) as a controlled hemorrhagic model, we examined various mitral flow parameters and three-dimensional reconstructions of left atrial volume as surrogates of LVEDP. Our results demonstrate that peak E wave velocity and left atrial end-diastolic volume (LAEDV) correlated with known changes in intravascular volume associated with ANH. Although left atrial volumetric analysis was done offline in our study, recent advances in echocardiographic software may allow for continuous display and real-time calculation of LAEDV. Along with the ease and reproducibility of acquiring Doppler images of flow across the mitral valve, these two correlates of LVEDP may justify a more widespread use of TEE to optimize intraoperative fluid management. The clinical applicability of peak E wave velocity and LAEDV still needs to be validated during uncontrolled resuscitation. PMID:26236733

  8. 3D FEM analyses on flow field characteristics of the valveless piezoelectric pump

    NASA Astrophysics Data System (ADS)

    Huang, Jun; Zhang, Jianhui; Shi, Weidong; Wang, Yuan

    2016-06-01

    Due to the special transportation and heat transfer characteristics, the fractal-like Y-shape branching tube is used in valveless piezoelectric pumps as a no-moving-part valve. However, there have been little analyses on the flow resistance of the valveless piezoelectric pump, which is critical to the performance of the valveless piezoelectric pump with fractal-like Y-shape branching tubes. Flow field of the piezoelectric pump is analyzed by the finite element method, and the pattern of the velocity streamlines is revealed, which can well explain the difference of total flow resistances of the piezoelectric pump. Besides, simplified numerical method is employed to calculate the export flow rate of piezoelectric pump, and the flow field of the piezoelectric pump is presented. The FEM computation shows that the maximum flow rate is 16.4 mL/min. Compared with experimental result, the difference between them is just 55.5%, which verifies the FEM method. The reasons of the difference between dividing and merging flow resistance of the valveless piezoelectric pump with fractal-like Y-shape branching tubes are also investigated in this method. The proposed research provides the instruction to design of novel piezoelectric pump and a rapid method to analyse the pump flow rate.

  9. Time-lapse 3D VSP monitoring of a carbon dioxide injection project at Delhi Field, Louisiana

    NASA Astrophysics Data System (ADS)

    Lubis, Muhammad Husni Mubarak

    Delhi Field is a producing oil field located in northeastern Louisiana. The estimated original oil in place (OOIP) is 357 mmbo and approximately 54% of OOIP has been produced through the primary production and water-flooding. A CO2-EOR program has been implemented since November 2009 to recover an additional 17% of OOIP. Reservoir surveillance using time-lapse 3D seismic data has been conducted to monitor the CO2 sweep efficiency. The goal of this study is to monitor the CO2 flow-path in the area around the injector using time-lapse 3D VSP data. For this purpose, two 3D VSPs acquired in June 2010 and again in August 2011 were processed together. Fluid substitution and VSP modeling were performed to understand the influence of pore-fluid saturation change on VSP records. A cross-equalization was performed to improve the similarity of the datasets. This step is important to reduce the ambiguity in time-lapse observation. The splice of a 3D VSP image into the surface seismic data becomes the key point in determining the reflector of the reservoir. By integrating the observation from the modeling and the splice of 3D VSP image to surface seismic, the CO2 flow-path from injector 164-3 can be identified from 3D time-lapse VSP data. The CO2 was not radially distributed around the injector, but moved toward southwest direction. This finding is also consistent with the flow-path interpreted from surface seismic. This consistency implies that time-lapse 3D VSP surveys at Delhi Field confirm and augment the time-lapse interpretation from surface seismic data.

  10. Simulation of bootstrap current in 2D and 3D ideal magnetic fields in tokamaks

    NASA Astrophysics Data System (ADS)

    Raghunathan, M.; Graves, J. P.; Cooper, W. A.; Pedro, M.; Sauter, O.

    2016-09-01

    We aim to simulate the bootstrap current for a MAST-like spherical tokamak using two approaches for magnetic equilibria including externally caused 3D effects such as resonant magnetic perturbations (RMPs), the effect of toroidal ripple, and intrinsic 3D effects such as non-resonant internal kink modes. The first approach relies on known neoclassical coefficients in ideal MHD equilibria, using the Sauter (Sauter et al 1999 Phys. Plasmas 6 2834) expression valid for all collisionalities in axisymmetry, and the second approach being the quasi-analytic Shaing–Callen (Shaing and Callen 1983 Phys. Fluids 26 3315) model in the collisionless regime for 3D. Using the ideal free-boundary magnetohydrodynamic code VMEC, we compute the flux-surface averaged bootstrap current density, with the Sauter and Shaing–Callen expressions for 2D and 3D ideal MHD equilibria including an edge pressure barrier with the application of resonant magnetic perturbations, and equilibria possessing a saturated non-resonant 1/1 internal kink mode with a weak internal pressure barrier. We compare the applicability of the self-consistent iterative model on the 3D applications and discuss the limitations and advantages of each bootstrap current model for each type of equilibrium.

  11. Constraints on Crustal Shear Wave Velocity Structure beneath Central Tibet from 3-D Multi-scale Finite-frequency Rayleigh Wave Travel-time Tomography

    NASA Astrophysics Data System (ADS)

    Jheng, Y.; Hung, S.; Zhou, Y.; Chang, Y.

    2012-12-01

    Surface wave travel-time tomography has been widely used as a powerful strategy to image shear wave velocity structure of the Earth's crust and upper mantle, providing comparable information other than body wave tomography. Traditionally, lateral variations of dispersive phase velocities are first obtained at multiple frequencies and then used to invert for shear wave velocity with 1-D depth-dependent sensitivity kernels. However, this approach runs short on considering the directional- and depth-dependence of scattering while surface wave propagating through laterally heterogeneous Earth. To refrain from these shortcomings, we here provide a fully 3-D finite-frequency method based on the Born scattering theory formulated with surface wave mode summation, and apply it to regional fundamental Rayleigh wave travel-time tomography in central Tibet. Our data were collected from Project Hi-CLIMB, which deployed an N-S trending linear array of over 100 broadband seismic stations with a large aperture of 800 km and very dense spacing of ~3-8 km across the Lhasa and Qiangtang terranes during 2004-2005. We follow a standard procedure of ambient noise cross correlation to extract empirical Green's functions of fundamental Rayleigh waves at 10-33 s between station pairs. A multi-taper method is employed to measure the phase differences as a function of period between observed and synthetic Rayleigh waves as well as the corresponding sensitivity kernels for the measured phase delays to 3-D shear wave velocity perturbations in a spherically-symmetric model suitable for central Tibet. A wavelet-based, multi-scale parameterization is invoked in the tomographic inversion to deal with the intrinsically multi-scale nature of unevenly distributed data and resolve the structure with data-adaptive spectral and spatial resolutions. The preliminary result shows that to the north of the Banggong-Nujiang suture (BNS), the crustal shear wave velocity beneath the Qiangtang terrane is

  12. Non-linear dynamics of viscous bilayers subjected to an electric field: 3D phase field simulations

    NASA Astrophysics Data System (ADS)

    Dritselis, Christos; Karapetsas, George; Bontozoglou, Vasilis

    2014-11-01

    The scope of this work is to investigate the non-linear dynamics of the electro-hydrodynamic instability of a bilayer of immiscible liquids. We consider the case of two viscous films which is separated from the top electrode by air. We assume that the liquids are perfect dielectrics and consider the case of both flat and patterned electrodes. We develop a computational model using the diffuse interface method and carry out 3D numerical simulations fully accounting for the flow and electric field in all phases. We perform a parametric study and investigate the influence of the electric properties of fluids, applied voltage and various geometrical characteristics of the mask. The authors acknowledge the support by the General Secretariat of Research and Technology of Greece under the action ``Supporting Postdoctoral Researchers'' (Grant Number PE8/906), co-funded by the European Social Fund and National Resources.

  13. Segmentation of Image Data from Complex Organotypic 3D Models of Cancer Tissues with Markov Random Fields

    PubMed Central

    Robinson, Sean; Guyon, Laurent; Nevalainen, Jaakko; Toriseva, Mervi

    2015-01-01

    Organotypic, three dimensional (3D) cell culture models of epithelial tumour types such as prostate cancer recapitulate key aspects of the architecture and histology of solid cancers. Morphometric analysis of multicellular 3D organoids is particularly important when additional components such as the extracellular matrix and tumour microenvironment are included in the model. The complexity of such models has so far limited their successful implementation. There is a great need for automatic, accurate and robust image segmentation tools to facilitate the analysis of such biologically relevant 3D cell culture models. We present a segmentation method based on Markov random fields (MRFs) and illustrate our method using 3D stack image data from an organotypic 3D model of prostate cancer cells co-cultured with cancer-associated fibroblasts (CAFs). The 3D segmentation output suggests that these cell types are in physical contact with each other within the model, which has important implications for tumour biology. Segmentation performance is quantified using ground truth labels and we show how each step of our method increases segmentation accuracy. We provide the ground truth labels along with the image data and code. Using independent image data we show that our segmentation method is also more generally applicable to other types of cellular microscopy and not only limited to fluorescence microscopy. PMID:26630674

  14. Potential Geophysical Field Transformations and Combined 3D Modelling for Estimation the Seismic Site Effects on Example of Israel

    NASA Astrophysics Data System (ADS)

    Eppelbaum, Lev; Meirova, Tatiana

    2015-04-01

    It is well-known that the local seismic site effects may have a significant contribution to the intensity of damage and destruction (e.g., Hough et al., 1990; Regnier et al., 2000; Bonnefoy-Claudet et al., 2006; Haase et al., 2010). The thicknesses of sediments, which play a large role in amplification, usually are derived from seismic velocities. At the same time, thickness of sediments may be determined (or defined) on the basis of 3D combined gravity-magnetic modeling joined with available geological materials, seismic data and borehole section examination. Final result of such investigation is a 3D physical-geological model (PGM) reflecting main geological peculiarities of the area under study. Such a combined study needs in application of a reliable 3D mathematical algorithm of computation together with advanced methodology of 3D modeling. For this analysis the developed GSFC software was selected. The GSFC (Geological Space Field Calculation) program was developed for solving a direct 3-D gravity and magnetic prospecting problem under complex geological conditions (Khesin et al., 1996; Eppelbaum and Khesin, 2004). This program has been designed for computing the field of Δg (Bouguer, free-air or observed value anomalies), ΔZ, ΔX, ΔY , ΔT , as well as second derivatives of the gravitational potential under conditions of rugged relief and inclined magnetization. The geological space can be approximated by (1) three-dimensional, (2) semi-infinite bodies and (3) those infinite along the strike closed, L.H. non-closed, R.H. on-closed and open). Geological bodies are approximated by horizontal polygonal prisms. The program has the following main advantages (besides abovementioned ones): (1) Simultaneous computing of gravity and magnetic fields; (2) Description of the terrain relief by irregularly placed characteristic points; (3) Computation of the effect of the earth-air boundary by the method of selection directly in the process of interpretation; (4

  15. 9C-3D seismic interpretation of the Bakken Formation, Banner Field, North Dakota

    NASA Astrophysics Data System (ADS)

    Comegys, Lillian R.

    The Bakken Petroleum System is a multi-reservoir play with estimated total undiscovered resources of 3.649 BBO oil and 1.85 TCF natural gas in the United States portion of the Williston Basin (Pollastro 2008). The presence of natural fractures in all three members of the Bakken Formation have been linked to high initial production (IP) and cumulative production from the Antelope Field and better reservoir potential in the Elm Coulee Field and Sanish Fields (Sturm and Gomez 2009; Honsberger 2012; Theloy 2011). Therefore, the ability of seismic data to determine the presence, orientation, and density of natural fractures is an important achievement for petroleum exploration and exploitation. The STAMPEDE 9-component seismic survey is located in Mountrail County, North Dakota, in the Banner Field, southeast of the Parshall and Sanish Fields. It is the goal of the Reservoir Characterization Project to analyze the structural influences on reservoir properties in the STAMPEDE survey area using the compressional and pure shear seismic volumes supplemented by the public well information available on the North Dakota Industrial Commission website. Fracturing induced by basement faulting and lithology changes is detectable using multicomponent seismic data in the Stampede seismic survey. Shear wave splitting analysis delineates zones of different fracture orientation and density. These areas correlate to interpreted fault intersections and the predicted area of increased fracture frequency based on facies changes in the Middle Bakken Member and its mechanical stratigraphy. Wrench fault mechanics are at work in the study area, creating isolated convergent and divergent stress regimes in the separate fault blocks. Main fault interpretations are based on shear wave isochron mapping, wireline log mapping, seismic panel observations. Fracture interpretations were made on the analysis of shear time and amplitude anisotropy maps and the correlation of a P-wave Velocity Variation

  16. Extended field-of-view and increased-signal 3D holographic illumination with time-division multiplexing

    PubMed Central

    Yang, Samuel J.; Allen, William E.; Kauvar, Isaac; Andalman, Aaron S.; Young, Noah P.; Kim, Christina K.; Marshel, James H.; Wetzstein, Gordon; Deisseroth, Karl

    2016-01-01

    Phase spatial light modulators (SLMs) are widely used for generating multifocal three-dimensional (3D) illumination patterns, but these are limited to a field of view constrained by the pixel count or size of the SLM. Further, with two-photon SLM-based excitation, increasing the number of focal spots penalizes the total signal linearly—requiring more laser power than is available or can be tolerated by the sample. Here we analyze and demonstrate a method of using galvanometer mirrors to time-sequentially reposition multiple 3D holograms, both extending the field of view and increasing the total time-averaged two-photon signal. We apply our approach to 3D two-photon in vivo neuronal calcium imaging. PMID:26699047

  17. Extended field-of-view and increased-signal 3D holographic illumination with time-division multiplexing.

    PubMed

    Yang, Samuel J; Allen, William E; Kauvar, Isaac; Andalman, Aaron S; Young, Noah P; Kim, Christina K; Marshel, James H; Wetzstein, Gordon; Deisseroth, Karl

    2015-12-14

    Phase spatial light modulators (SLMs) are widely used for generating multifocal three-dimensional (3D) illumination patterns, but these are limited to a field of view constrained by the pixel count or size of the SLM. Further, with two-photon SLM-based excitation, increasing the number of focal spots penalizes the total signal linearly--requiring more laser power than is available or can be tolerated by the sample. Here we analyze and demonstrate a method of using galvanometer mirrors to time-sequentially reposition multiple 3D holograms, both extending the field of view and increasing the total time-averaged two-photon signal. We apply our approach to 3D two-photon in vivo neuronal calcium imaging. PMID:26699047

  18. Fast 3D dark-field reflection-mode photoacoustic microscopy in vivo with a 30-MHz ultrasound linear array

    PubMed Central

    Song, Liang; Maslov, Konstantin; Bitton, Rachel; Shung, K. Kirk; Wang, Lihong V.

    2009-01-01

    We present an in vivo dark-field reflection-mode photoacoustic microscopy system that performs cross-sectional (B-scan) imaging at 50 Hz with realtime beamforming and 3D imaging consisting of 166 B-scan frames at 1 Hz with post-beamforming. To our knowledge, this speed is currently the fastest in photoacoustic imaging. A custom-designed light delivery system is integrated with a 30-MHz ultrasound linear array to realize dark-field reflection-mode imaging. Linear mechanical scanning of the array produces 3D images. The system has axial, lateral, and elevational resolutions of 25, 70, and 200 μm, respectively, and can image 3 mm deep in scattering biological tissues. Volumetric images of subcutaneous vasculature in rats are demonstrated in vivo. Fast 3D photoacoustic microscopy is anticipated to facilitate applications of photoacoustic imaging in biomedical studies that involve dynamics and clinical procedures that demand immediate diagnosis. PMID:19021408

  19. Near field 3D displacement of El Mayor-Cupapah Earthquake: A hybrid approach. (Invited)

    NASA Astrophysics Data System (ADS)

    Hinojosa-Corona, A.; Limon, F. J.; Nissen, E.; Glennie, C. L.; Krishnan, A.; Oskin, M. E.; Arrowsmith, R.; Leprince, S.; Saripalli, S.; Arregui, S. M.; Borsa, A. A.; Kreylos, O.; Banesh, D.; Fletcher, J. M.

    2013-12-01

    The surface rupture produced on April 4th of 2010 by the M 7.2 El Mayor-Cucapah Earthquake is an ideal target to be analyzed by remote sensing techniques. It produced over 100 km of scarps, with vertical and horizontal slip on the order of 2 to 3 m in scarcely vegetated, rugged terrain underlain by mostly igneous rocks. A 3D displacement field (DF) was calculated by matching pre- to post-event airborne LiDAR point clouds through the Iterative Closest Point (ICP) algorithm, which first segments the point clouds into discrete windows, and for each, iteratively converges on a rigid body transformation comprising a translation and a rotation that best aligns the pre- to post-event point clouds. After testing different window sizes, we used a square window 100m a side. The El Mayor-Cucapah LiDAR data sets present special challenges for the ICP technique. The point clouds differ considerably in point density, by ~1:700. This, and the lower precision of the pre-earthquake data, limit the accuracy of the DF results. Despite these issues, the vertical and East-West (E-W) components of the DF from ICP very clearly delineate the trace of the surface rupture, showing east-side down dextral-normal motion in agreement with field measurements and the focal mechanism reported for this event. A systematic error in the LiDAR instrument used for the pre-event survey caused severe distortion of the North-South (N-S) component of the LiDAR returns. After reprocessing the source pre-event point cloud in various ways to correct for the systematic error, a more plausible pattern for the N-S component was obtained for the DF. To have another perspective for the horizontal DF, a subpixel correlation analysis of optical satellite images (SPOT 2.5 m panchromatic images) before and after the earthquake, was performed using the COSI-Corr software. We combined the N-S component from this analysis with the E-W and vertical components of the ICP results, and present the analysis of the resulting

  20. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITH TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    five groups: 1) Grid Functions for grids, grid-checking, etc.; 2) Scalar Functions for contour or carpet plots of density, pressure, temperature, Mach number, vorticity magnitude, helicity, etc.; 3) Vector Functions for vector plots of velocity, vorticity, momentum, and density gradient, etc.; 4) Particle Trace Functions for rake-like plots of particle flow or vortex lines; and 5) Shock locations based on pressure gradient. TURB3D is a modification of PLOT3D which is used for viewing CFD simulations of incompressible turbulent flow. Input flow data consists of pressure, velocity and vorticity. Typical quantities to plot include local fluctuations in flow quantities and turbulent production terms, plotted in physical or wall units. PLOT3D/TURB3D includes both TURB3D and PLOT3D because the operation of TURB3D is identical to PLOT3D, and there is no additional sample data or printed documentation for TURB3D. Graphical capabilities of PLOT3D version 3.6b+ vary among the implementations available through COSMIC. Customers are encouraged to purchase and carefully review the PLOT3D manual before ordering the program for a specific computer and graphics library. There is only one manual for use with all implementations of PLOT3D, and although this manual generally assumes that the Silicon Graphics Iris implementation is being used, informative comments concerning other implementations appear throughout the text. With all implementations, the visual representation of the object and flow field created by PLOT3D consists of points, lines, and polygons. Points can be represented with dots or symbols, color can be used to denote data values, and perspective is used to show depth. Differences among implementations impact the program's ability to use graphical features that are based on 3D polygons, the user's ability to manipulate the graphical displays, and the user's ability to obtain alternate forms of output. The Apollo implementation of PLOT3D uses some of the capabilities of

  1. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITHOUT TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    five groups: 1) Grid Functions for grids, grid-checking, etc.; 2) Scalar Functions for contour or carpet plots of density, pressure, temperature, Mach number, vorticity magnitude, helicity, etc.; 3) Vector Functions for vector plots of velocity, vorticity, momentum, and density gradient, etc.; 4) Particle Trace Functions for rake-like plots of particle flow or vortex lines; and 5) Shock locations based on pressure gradient. TURB3D is a modification of PLOT3D which is used for viewing CFD simulations of incompressible turbulent flow. Input flow data consists of pressure, velocity and vorticity. Typical quantities to plot include local fluctuations in flow quantities and turbulent production terms, plotted in physical or wall units. PLOT3D/TURB3D includes both TURB3D and PLOT3D because the operation of TURB3D is identical to PLOT3D, and there is no additional sample data or printed documentation for TURB3D. Graphical capabilities of PLOT3D version 3.6b+ vary among the implementations available through COSMIC. Customers are encouraged to purchase and carefully review the PLOT3D manual before ordering the program for a specific computer and graphics library. There is only one manual for use with all implementations of PLOT3D, and although this manual generally assumes that the Silicon Graphics Iris implementation is being used, informative comments concerning other implementations appear throughout the text. With all implementations, the visual representation of the object and flow field created by PLOT3D consists of points, lines, and polygons. Points can be represented with dots or symbols, color can be used to denote data values, and perspective is used to show depth. Differences among implementations impact the program's ability to use graphical features that are based on 3D polygons, the user's ability to manipulate the graphical displays, and the user's ability to obtain alternate forms of output. The Apollo implementation of PLOT3D uses some of the capabilities of

  2. Online Stereo 3D Simulation in Studying the Spherical Pendulum in Conservative Force Field

    ERIC Educational Resources Information Center

    Zabunov, Svetoslav S.

    2013-01-01

    The current paper aims at presenting a modern e-learning method and tool that is utilized in teaching physics in the universities. An online stereo 3D simulation is used for e-learning mechanics and specifically the teaching of spherical pendulum as part of the General Physics course for students in the universities. This approach was realized on…

  3. Anisotropic 3-D Crustal Velocity Structure of Idaho/ Oregon from a Joint Inversion of Group and Phase Velocities of Love and Rayleigh Waves from Ambient Seismic Noise: Results from the IDOR Project

    NASA Astrophysics Data System (ADS)

    Bremner, P. M.; Panning, M. P.; Russo, R.; Mocanu, V. I.; Stanciu, A. C.; Torpey, M. E.; Hongsresawat, S.; VanDecar, J. C.

    2015-12-01

    We present new 3-D radially anisotropic and isotropic crustal velocity models beneath central Idaho and eastern Oregon. We produced the velocity models from Love and horizontal component Rayleigh wave group and phase velocity measurements on the IDaho/ORegon (IDOR) Passive seismic network, 86 broadband seismic stations, dataset using ambient noise tomography and the methods of Gallego et. al (2010) and Lin et. al (2008). We calculated inter-station group/phase velocities in narrow frequency bands from travel-time measurements of the rotated stacked horizontal component cross-correlations (bandpass filtered between 2 and 30 seconds), which we used to invert for velocity structure beneath the network. We derived group and phase velocity maps for each frequency band using the damped least-squares inversion method of Tarantola (2005), and then jointly inverted for velocity with depth. Moho depths are prescribed in the joint inversions based on receiver functions, also from the IDOR seismic data, and provides a starting crustal velocity model. Goals of our work include refining models of crustal structure in the accreted Blue Mountain terranes in the western study area; determining the depth extent of the Salmon River Suture/West Idaho Shear Zone (WISZ), which crosses north-south through the middle of the network; determining the architecture of the Idaho batholith, an extensive largely crustal-derived pluton; and examining the nature of the autochthonous (?) North American crust and lithosphere beneath and east of the batholith.

  4. Preliminary result of teleseismic double-difference relocation of earthquakes in the Molucca collision zone with a 3D velocity model

    NASA Astrophysics Data System (ADS)

    Shiddiqi, Hasbi Ash; Widiyantoro, Sri; Nugraha, Andri Dian; Ramdhan, Mohamad; Wandono, Sutiyono, Handayani, Titi; Nugroho, Hendro

    2015-04-01

    We have relocated hypocenters of earthquakes occurring in the Molucca collision zone and surrounding region taken from the BMKG catalog using teleseismic double-difference relocation algorithm (teletomoDD). We used P-wave arrival times of local, regional, and teleseismic events recorded at 304 recording stations. Over 7,000 earthquakes were recorded by the BMKG seismographicnetworkin the study region from April, 2009 toJune, 2014. We used a 3D regional-global nested velocity modelresulting fromprevious global tomographystudy. In this study, the3D seismic velocity model was appliedto theIndonesian region, whilethe1D seismicvelocity model (ak135)wasused for regions outside of Indonesia. Our relocation results show a better improvement in travel-time RMS residuals comparedto those of the BMKG catalog.Ourresultsalso show that relocation shifts were dominated intheeast-west direction, whichmaybeinfluenced by theexistingvelocity anomaly related to the reversed V-shaped slabbeneaththestudy region. Our eventrelocation results refine the geometry of slabs beneath the Halmahera and Sangihe arcs.

  5. Preliminary result of teleseismic double-difference relocation of earthquakes in the Molucca collision zone with a 3D velocity model

    SciTech Connect

    Shiddiqi, Hasbi Ash E-mail: h.a.shiddiqi@gmail.com; Widiyantoro, Sri; Nugraha, Andri Dian; Ramdhan, Mohamad; Wandono,; Sutiyono,; Handayani, Titi; Nugroho, Hendro

    2015-04-24

    We have relocated hypocenters of earthquakes occurring in the Molucca collision zone and surrounding region taken from the BMKG catalog using teleseismic double-difference relocation algorithm (teletomoDD). We used P-wave arrival times of local, regional, and teleseismic events recorded at 304 recording stations. Over 7,000 earthquakes were recorded by the BMKG seismographicnetworkin the study region from April, 2009 toJune, 2014. We used a 3D regional-global nested velocity modelresulting fromprevious global tomographystudy. In this study, the3D seismic velocity model was appliedto theIndonesian region, whilethe1D seismicvelocity model (ak135)wasused for regions outside of Indonesia. Our relocation results show a better improvement in travel-time RMS residuals comparedto those of the BMKG catalog.Ourresultsalso show that relocation shifts were dominated intheeast-west direction, whichmaybeinfluenced by theexistingvelocity anomaly related to the reversed V-shaped slabbeneaththestudy region. Our eventrelocation results refine the geometry of slabs beneath the Halmahera and Sangihe arcs.

  6. Relationship of P-wave seismic attributes, azimuthal anisotropy, and commercial gas pay in 3-D P-wave multiazimuth data, Rulison field, Piceance Basin, Colorado

    SciTech Connect

    Lynn, H.B.; Campagna, D.; Simon, K.M.; Beckham, W.E.

    1999-08-01

    This case history is one of three field projects funded by the US Department of Energy a part of its ongoing research effort aimed to expand current levels of drilling and production efficiency in naturally-fractured tight-gas reservoirs. The original states goal for the 3-D P-wave seismic survey was to evaluate and map fracture azimuth and relative fracture density throughout a naturally-fractured gas reservoir interval. At Rulison field, this interval is the Cretaceous Mesaverde, approximately 2,500 ft (760 m) of lenticular sands, silts, and shales. Three-dimensional full-azimuth P-wave data were acquired for the evaluation of azimuthal anisotropy and the relationship of the anisotropy to commercial pay in the target interval. The methodology is based on the evaluation of two restricted-azimuth orthogonal (source receiver azimuth) 3-D P-wave volumes aligned with the natural principal axes of the azimuthal anisotropy, as estimated from velocity analysis of multiazimuth prestack gathers. The Dix interval velocity, as well as the interval amplitude variation with offset (AVO) gradient, was calculated for both azimuths for the gas-saturated Mesaverde interval. The two seismic attributes best correlated with commercial gas pay (at a 21-well control set) were (1) values greater than 4% azimuthal variation in the interval velocity ratio (source-receiver azimuth N60E/N30W) of the target interval (the gas-saturated Mesaverde), and (2) the sum of the interval AVO gradients (N60E + N30W). The sum of the interval AVO gradients is an attribute sensitive to the presence of gas, but not diagnostic of an azimuthal variation in the amplitude. The two-azimuth interval velocity anisotropy mapped over the survey area suggests spatial variations in the orientation of the maximum horizontal stress field and the open (to flow) fracture system.

  7. Validation of a CFD Model by Using 3D Sonic Anemometers to Analyse the Air Velocity Generated by an Air-Assisted Sprayer Equipped with Two Axial Fans

    PubMed Central

    García-Ramos, F. Javier; Malón, Hugo; Aguirre, A. Javier; Boné, Antonio; Puyuelo, Javier; Vidal, Mariano

    2015-01-01

    A computational fluid dynamics (CFD) model of the air flow generated by an air-assisted sprayer equipped with two axial fans was developed and validated by practical experiments in the laboratory. The CFD model was developed by considering the total air flow supplied by the sprayer fan to be the main parameter, rather than the outlet air velocity. The model was developed for three air flows corresponding to three fan blade settings and assuming that the sprayer is stationary. Actual measurements of the air velocity near the sprayer were taken using 3D sonic anemometers. The workspace sprayer was divided into three sections, and the air velocity was measured in each section on both sides of the machine at a horizontal distance of 1.5, 2.5, and 3.5 m from the machine, and at heights of 1, 2, 3, and 4 m above the ground The coefficient of determination (R2) between the simulated and measured values was 0.859, which demonstrates a good correlation between the simulated and measured data. Considering the overall data, the air velocity values produced by the CFD model were not significantly different from the measured values. PMID:25621611

  8. The LLNL-G3D global P-wave velocity model and the significance of the BayesLoc multiple-event location procedure

    NASA Astrophysics Data System (ADS)

    Simmons, N. A.; Myers, S. C.; Johannesson, G.; Matzel, E.

    2011-12-01

    LLNL-G3D is a global-scale model of P-wave velocity designed to accurately predict seismic travel times at regional and teleseismic distances simultaneously. The underlying goal of the model is to provide enhanced seismic event location capabilities. Previous versions of LLNL-G3D (versions 1 and 2) provide substantial improvements in event location accuracy via 3-D ray tracing. The latest models are based on ~2.7 million P and Pn arrivals that are re-processed using our global multi-event locator known as BayesLoc. Bayesloc is a formulation of the joint probability distribution across multiple-event location parameters, including hypocenters, travel time corrections, pick precision, and phase labels. Modeling the whole multiple-event system results in accurate locations and an internally consistent data set that is ideal for tomography. Our recently developed inversion approach (called Progressive Multi-level Tessellation Inversion or PMTI) captures regional trends and fine details where data warrant. Using PMTI, we model multiple heterogeneity scale lengths without defining parameter grids with variable densities based on some ad hoc criteria. LLNL-G3Dv3 (version 3) is produced with data generated with the BayesLoc procedure, recently modified to account for localized travel time trends via a multiple event clustering technique. We demonstrate the significance of BayesLoc processing, the impact on the resulting tomographic images, and the application of LLNL-G3D to seismic event location. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-491805.

  9. How Students and Field Geologists Reason in Integrating Spatial Observations from Outcrops to Visualize a 3-D Geological Structure

    ERIC Educational Resources Information Center

    Kastens, Kim A.; Agrawal, Shruti; Liben, Lynn S.

    2009-01-01

    Geologists and undergraduate students observed eight artificial "rock outcrops" in a realistically scaled field area, and then tried to envision a geological structure that might plausibly be formed by the layered rocks in the set of outcrops. Students were videotaped as they selected which of fourteen 3-D models they thought best represented the…

  10. Properties of the prominence magnetic field and plasma distributions as obtained from 3D whole-prominence fine structure modeling

    NASA Astrophysics Data System (ADS)

    Gunár, S.; Mackay, D. H.

    2016-07-01

    Aims: We analyze distributions of the magnetic field strength and prominence plasma (temperature, pressure, plasma β, and mass) using the 3D whole-prominence fine structure model. Methods: The model combines a 3D magnetic field configuration of an entire prominence, obtained from non-linear force-free field simulations, with a detailed semi-empirically derived description of the prominence plasma. The plasma is located in magnetic dips in hydrostatic equilibrium and is distributed along multiple fine structures within the 3D magnetic model. Results: We show that in the modeled prominence, the variations of the magnetic field strength and its orientation are insignificant on scales comparable to the smallest dimensions of the observed prominence fine structures. We also show the ability of the 3D whole-prominence fine structure model to reveal the distribution of the prominence plasma with respect to its temperature within the prominence volume. This provides new insights into the composition of the prominence-corona transition region. We further demonstrate that the values of the plasma β are small throughout the majority of the modeled prominences when realistic photospheric magnetic flux distributions and prominence plasma parameters are assumed. While this is generally true, we also find that in the region with the deepest magnetic dips, the plasma β may increase towards unity. Finally, we show that the mass of the modeled prominence plasma is in good agreement with the mass of observed non-eruptive prominences.

  11. The 3-D distribution of random velocity inhomogeneities in southwestern Japan and the western part of the Nankai subduction zone

    NASA Astrophysics Data System (ADS)

    Takahashi, Tsutomu; Obana, Koichiro; Yamamoto, Yojiro; Nakanishi, Ayako; Kodaira, Shuichi; Kaneda, Yoshiyuki

    2013-05-01

    waves at high frequencies (>1 Hz) show collapsed and broadened wave trains caused by multiple scattering in the lithosphere. This study analyzed the envelopes of direct S waves in southwestern Japan and on the western side of the Nankai trough and estimated the spatial distribution of random inhomogeneities by assuming a von Kármán type power spectral density function (PSDF). Strongly inhomogeneous media have been mostly imaged at shallow depth (0-20 km depth) in the onshore area of southwestern Japan, and their PSDF is represented as P(m) ≈ 0.05m-3.7 km3, with m being the spatial wave number, whereas most of the other area shows weak inhomogeneities of which PSDF is P(m) ≈ 0.005m-4.5 km3. At Hyuga-nada in Nankai trough, there is an anomaly of inhomogeneity of which PSDF is estimated as P(m) ≈ 0.01m-4.5 km3. This PSDF has the similar spectral gradient with the weakly inhomogeneous media, but has larger power spectral density than other offshore areas. This anomalous region is broadly located in the subducted Kyushu Palau ridge, which was identified by using velocity structures and bathymetry, and it shows no clear correlation with the fault zones of large earthquakes in past decades. These spatial correlations suggest that possible origins of inhomogeneities at Hyuga-nada are ancient volcanic activity in the oceanic plate or deformed structures due to the subduction of the Kyushu Palau ridge.

  12. Toward real-time endoscopically-guided robotic navigation based on a 3D virtual surgical field model

    NASA Astrophysics Data System (ADS)

    Gong, Yuanzheng; Hu, Danying; Hannaford, Blake; Seibel, Eric J.

    2015-03-01

    The challenge is to accurately guide the surgical tool within the three-dimensional (3D) surgical field for roboticallyassisted operations such as tumor margin removal from a debulked brain tumor cavity. The proposed technique is 3D image-guided surgical navigation based on matching intraoperative video frames to a 3D virtual model of the surgical field. A small laser-scanning endoscopic camera was attached to a mock minimally-invasive surgical tool that was manipulated toward a region of interest (residual tumor) within a phantom of a debulked brain tumor. Video frames from the endoscope provided features that were matched to the 3D virtual model, which were reconstructed earlier by raster scanning over the surgical field. Camera pose (position and orientation) is recovered by implementing a constrained bundle adjustment algorithm. Navigational error during the approach to fluorescence target (residual tumor) is determined by comparing the calculated camera pose to the measured camera pose using a micro-positioning stage. From these preliminary results, computation efficiency of the algorithm in MATLAB code is near real-time (2.5 sec for each estimation of pose), which can be improved by implementation in C++. Error analysis produced 3-mm distance error and 2.5 degree of orientation error on average. The sources of these errors come from 1) inaccuracy of the 3D virtual model, generated on a calibrated RAVEN robotic platform with stereo tracking; 2) inaccuracy of endoscope intrinsic parameters, such as focal length; and 3) any endoscopic image distortion from scanning irregularities. This work demonstrates feasibility of micro-camera 3D guidance of a robotic surgical tool.

  13. Modeling of 3d Space-time Surface of Potential Fields and Hydrogeologic Modeling of Nuclear Waste Disposal Sites

    NASA Astrophysics Data System (ADS)

    Shestopalov, V.; Bondarenko, Y.; Zayonts, I.; Rudenko, Y.

    Introduction After the Chernobyl Nuclear Power Plant (CNPP) disaster (04.26.1986) a huge amount (over 2000 sq. km) of nuclear wastes appeared within so-called "Cher- nobyl Exclusion Zone" (CEZ). At present there are not enough storage facilities in the Ukraine for safe disposal of nuclear wastes and hazardous chemical wastes. The urgent problem now is safe isolation of these dangerous wastes. According to the developed state program of radioactive waste management, the construction of a na- tional storage facility of nuclear wastes is planned. It is also possible to create regional storage facilities for hazardous chemical wastes. The region of our exploration cov- ers the eastern part of the Korosten Plutone and its slope, reaching the CNPP. 3D Space-Time Surface Imaging of Geophysical Fields. There are only three direct meth- ods of stress field reconstruction in present practice, namely the field investigations based on the large-scale fracturing tests, petrotectonic and optical polarization meth- ods. Unfortunately, all these methods are extremely laborious and need the regular field tests, which is difficult to conduct in the areas of anisotropic rock outcrops. A compilation of magnetic and gravity data covering the CNPP area was carried out as a prelude to an interpretation study. More than thirty map products were generated from magnetic, gravity and geodesy data to prepare the 3D Space-Time Surface Images (3D STSI). Multi-layer topography and geophysic surfaces included: total magnetic intensity, isostatically-corrected Bouguer gravity, aspect and slope, first and second derivatives, vertical and horizontal curvature, histogram characteristics and space cor- relation coefficients between the gradient fields. Many maps shows the first and sec- ond derivatives of the potential fields, with the results of lineament (edge) structure detection superimposed. The lineament or edges of the potential fields are located from maximal gradient in many directions

  14. Test of high-resolution 3D P-wave velocity model of Poland by back-azimuthal sections of teleseismic receiver function

    NASA Astrophysics Data System (ADS)

    Wilde-Piorko, Monika; Polkowski, Marcin; Grad, Marek

    2015-04-01

    Geological and seismic structure under area of Poland is well studied by over one hundred thousand boreholes, over thirty deep seismic refraction and wide angle reflection profiles and by vertical seismic profiling, magnetic, gravity, magnetotelluric and thermal methods. Compilation of these studies allowed to create a high-resolution 3D P-wave velocity model down to 60 km depth in the area of Poland (Polkowski et al. 2014). Model also provides details about the geometry of main layers of sediments (Tertiary and Quaternary, Cretaceous, Jurassic, Triassic, Permian, old Paleozoic), consolidated/crystalline crust (upper, middle and lower) and uppermost mantle. This model gives an unique opportunity for calculation synthetic receiver function and compering it with observed receiver function calculated for permanent and temporary seismic stations. Modified ray-tracing method (Langston, 1977) can be used directly to calculate the response of the structure with dipping interfaces to the incoming plane wave with fixed slowness and back-azimuth. So, 3D P-wave velocity model has been interpolated to 2.5D P-wave velocity model beneath each seismic station and back-azimuthal sections of components of receiver function have been calculated. Vp/Vs ratio is assumed to be 1.8, 1.67, 1.73, 1.77 and 1.8 in the sediments, upper/middle/lower consolidated/crystalline crust and uppermost mantle, respectively. Densities were calculated with combined formulas of Berteussen (1977) and Gardner et al. (1974). Additionally, to test a visibility of the lithosphere-asthenosphere boundary phases at receiver function sections models have been extended to 250 km depth based on P4-mantle model (Wilde-Piórko et al., 2010). National Science Centre Poland provided financial support for this work by NCN grant DEC-2011/02/A/ST10/00284 and by NCN grant UMO-2011/01/B/ST10/06653.

  15. Numerical simulation of internal and external inviscid and viscous 3-D flow fields

    NASA Astrophysics Data System (ADS)

    Leicher, Stefan

    1986-11-01

    A numerical method for solving the 3-D Euler equations in geometrical complex domains was developed. The approach divides the computational space into multiple blocks whose structure follows the natural lines of the conficuration. A systematic, multi-block grid generation scheme is used to produce the grid. The flow solutions are obtained by solving the Euler equations by a finite volume discretization and a Runge-Kutta time stepping scheme. The main advantage of this method is the applicability to complex geometries, for example complete aircraft configurations including wing, fuselage, canard and tail. The coupling with a 3-D boundary layer method allows to account for viscous effects. Another application for the method was the simulation of flows in the presence of a propeller.

  16. Wide-field hyperspectral 3D imaging of functionalized gold nanoparticles targeting cancer cells by reflected light microscopy.

    PubMed

    Patskovsky, Sergiy; Bergeron, Eric; Rioux, David; Meunier, Michel

    2015-05-01

    We present a new hyperspectral reflected light microscopy system with a scanned broadband supercontinuum light source. This wide-field and low phototoxic hyperspectral imaging system has been successful for performing spectral three-dimensional (3D) localization and spectroscopic identification of CD44-targeted PEGylated AuNPs in fixed cell preparations. Such spatial and spectral information is essential for the improvement of nanoplasmonic-based imaging, disease detection and treatment in complex biological environment. The presented system can be used for real-time 3D NP tracking as spectral sensors, thus providing new avenues in the spatio-temporal characterization and detection of bioanalytes. 3D image of the distribution of functionalized AuNPs attached to CD44-expressing MDA-MB-231 human cancer cells. PMID:24961507

  17. The ATLAS3D project - XXI. Correlations between gradients of local escape velocity and stellar populations in early-type galaxies

    NASA Astrophysics Data System (ADS)

    Scott, Nicholas; Cappellari, Michele; Davies, Roger L.; Kleijn, Gijs Verdoes; Bois, Maxime; Alatalo, Katherine; Blitz, Leo; Bournaud, Frédéric; Bureau, Martin; Crocker, Alison; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; McDermid, Richard M.; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    2013-07-01

    We explore the connection between the local escape velocity, Vesc, and the stellar population properties in the ATLAS3D survey, a complete, volume-limited sample of nearby early-type galaxies. We make use of ugriz photometry to construct Multi-Gaussian Expansion models of the surface brightnesses of our galaxies. We are able to fit the full range of surface brightness profiles found in our sample, and in addition we reproduce the results of state-of-the-art photometry in the literature with residuals of 0.04 mag. We utilize these photometric models and SAURON integral-field spectroscopy, combined with Jeans dynamical modelling, to determine the local Vesc derived from the surface brightness. We find that the local Vesc is tightly correlated with the Mg b and Fe5015 line strengths and optical colours, and anti-correlated with the Hβ line strength. In the case of the Mg b and colour-Vesc relations we find that the relation within individual galaxies follows the global relation between different galaxies. We intentionally ignored any uncertain contribution due to dark matter since we are seeking an empirical description of stellar population gradients in early-type galaxies that is ideal for quantitative comparison with model predictions. We also make use of single stellar population (SSP) modelling to transform our line strength index measurements into the SSP-equivalent parameters age (t), metallicity ([Z/H]) and α-enhancement [α/Fe]. The residuals from the relation are correlated with age, [α/Fe], molecular gas mass and local environmental density. We identify a population of galaxies that occur only at low Vesc that exhibit negative gradients in the Mg b- and Colour-Vesc relations. These galaxies typically have young central stellar populations and contain significant amounts of molecular gas and dust. Combining these results with N-body simulations of binary mergers we use the Mg b-Vesc relation to constrain the possible number of dry mergers experienced by

  18. Relocation of the Waldkirch seismic event, December 5, 2004, with regional 1D- and 3D-velocity models in the presence of upper mantle anisotropy

    NASA Astrophysics Data System (ADS)

    Muench, Thomas; Koch, Manfred; Schlittenhard, Jörg

    2010-05-01

    On December 5, 2004 a strong earthquake occurred near the city of Waldkirch, about 30 km's north of Freiburg, with a local magnitude of ML = 5.4. This seismic event was one of the strongest observed since the ML = 5.7 'Schwäbische Alb' event of September 3, 1978, 30 years before. In the aftermath of the event several institutions (Bens, BGR, LGBR, LED, SED and NEIC) have attempted to relocate this earthquake that came up with a hypocentral depth range of 9 - 12 km which. In fact, as the exact hypocentral location of the Waldkirch - and other events in the area - namely, the seismic depths, are of utmost importance for the further understanding of the seismotectonics as well as of the seismic hazard in the upper Rhinegraben area, one cannot over stress the necessity for a hypocenter relocation as best as possible. This requires a careful analysis of all factors that may impede an unbiased relocation of such an event. In the present talk we put forward the question whether the Waldkirch seismic event can be relocated with sufficient accuracy by a regional network when, additionally, improved regional 1D- and 3D seismic velocity models for the crust and upper mantle that take into consideration Pn-anisotropy of the upper mantle beneath Germany are employed in the hypocentral determination process. The seismological work starts with a comprehensive analysis of the dataset available for the relocation of the event. By means of traveltime curves a reevaluation of the observed phases is done and it is shown that some of the big observed traveltime residuals are most likely the consequence of wrongly associated phases as well as of the neglect of the anisotropic Pn traveltime correction for the region. Then hypcocenter relocations are done for 1D vertically inhomogeneous and 3D laterally inhomogeneous seismic velocity models, without and with the anisotropic Pn-traveltime correction included. The effects of the - often not well-known - Moho depth and of the VP

  19. Magnetic field induced controllable self-assembly of maghemite nanocrystals: From 3D arrays to 1D nanochains

    NASA Astrophysics Data System (ADS)

    Tang, Yan; Chen, Qianwang; Chen, Rongsheng

    2015-08-01

    A hydrothermal process has been used to synthesize walnut-like maghemite superstructures which can be further self-assembled in a controllable manner into ordered three-dimensional (3D) architectures and one-dimensional (1D) nanochains in the presence of different external magnetic field. The assembly behavior of the maghemite nanoparticles isclosely related to the van der Waals interactions and external-field-induced magnetic dipole interactions. The magnetic properties of these nanostructures are also investigated.

  20. 3D real-time visualization of blood flow in cerebral aneurysms by light field particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Carlsohn, Matthias F.; Kemmling, André; Petersen, Arne; Wietzke, Lennart

    2016-04-01

    Cerebral aneurysms require endovascular treatment to eliminate potentially lethal hemorrhagic rupture by hemostasis of blood flow within the aneurysm. Devices (e.g. coils and flow diverters) promote homeostasis, however, measurement of blood flow within an aneurysm or cerebral vessel before and after device placement on a microscopic level has not been possible so far. This would allow better individualized treatment planning and improve manufacture design of devices. For experimental analysis, direct measurement of real-time microscopic cerebrovascular flow in micro-structures may be an alternative to computed flow simulations. An application of microscopic aneurysm flow measurement on a regular basis to empirically assess a high number of different anatomic shapes and the corresponding effect of different devices would require a fast and reliable method at low cost with high throughout assessment. Transparent three dimensional 3D models of brain vessels and aneurysms may be used for microscopic flow measurements by particle image velocimetry (PIV), however, up to now the size of structures has set the limits for conventional 3D-imaging camera set-ups. On line flow assessment requires additional computational power to cope with the processing large amounts of data generated by sequences of multi-view stereo images, e.g. generated by a light field camera capturing the 3D information by plenoptic imaging of complex flow processes. Recently, a fast and low cost workflow for producing patient specific three dimensional models of cerebral arteries has been established by stereo-lithographic (SLA) 3D printing. These 3D arterial models are transparent an exhibit a replication precision within a submillimeter range required for accurate flow measurements under physiological conditions. We therefore test the feasibility of microscopic flow measurements by PIV analysis using a plenoptic camera system capturing light field image sequences. Averaging across a sequence of

  1. 3-D P-wave velocity structure and seismicity in Central Costa Rica from Local Earthquake Tomography using an amphibic network

    NASA Astrophysics Data System (ADS)

    Arroyo, I.; Husen, S.; Flueh, E.; Alvarado, G. E.

    2008-12-01

    The Central Pacific sector of the erosional margin in Costa Rica shows a high seismicity rate, coincident with the subduction of rough-relief ocean floor, and generates earthquakes up to Mw 7. Precise earthquake locations and detailed knowledge of the 3-D velocity structure provide key insights into the dynamics of subduction zones. To this end, we performed a 3-D Local Earthquake Tomography using P-wave traveltimes from 595 selected events recorded by a seismological network of off- and onshore stations, deployed for 6 months in the area. The results reflect the complexity associated to subduction of bathymetric highs and the transition from normal to thickened oceanic crust (Cocos Ridge). The slab is imaged as a high-velocity anomaly with a band of low velocities (LVB) on top enclosing the intraslab events deeper than ~30 km. Below the margin slope, the LVB is locally thickened by at least two seamounts. We observe an abrupt, eastward widening of the LVB, preceded by a low-velocity anomaly under the continental shelf, which we interpret as a big seamount. The thickening coincides with an inverted basin at the inner forearc and a low-velocity anomaly under it. The latter appears in a sector where blocks of inner forearc are uplifted, possibly by underplating of eroded material against the base of the crust. The anomaly promotes seismicity by high-friction with the upper plate, and could be linked to a Mw 6.4 earthquake in 2004. In the west part of the area, the interplate seismicity forms a cluster beneath the continental shelf. Its updip limit coincides with the 150° C isotherm and an increase in Vp along the plate boundary. This further supports a proposed model in which the seismicity onset along the plate interface is mainly due to a decrease in the abundance of the fluids released by subducted sediments. Higher seismicity rates locally concur with seamounts present at the seismogenic zone, while seamounts under the margin slope may shallow the onset of

  2. Dynamics of pickup ion velocity distribution function in Titan's plasma environment (TA encounter): 3D hybrid kinetic modeling and comparison with CAPS observations

    NASA Astrophysics Data System (ADS)

    Simpson, D. G.; Lipatov, A. S.; Sittler, E. C.; Hartle, R. E.; Cooper, J. F.

    2013-12-01

    Wave-particle interactions play a very important role in the plasma dynamics near Titan: mass loading, excitation of the low-frequency waves and the formation of the particle velocity distribution function, e.g. ring/shell-like distributions, etc. The kinetic approach is important for estimation of the collision processes e.g. a charge exchange. The particle velocity distribution function also plays a key role for understanding the observed particle fluxes. In this report we discuss the ion velocity distribution function dynamics from 3D hybrid modeling. The modeling is based on recent analysis of the Cassini Plasma Spectrometer (CAPS) ion measurements during the TA flyby. In our model the background ions, all pickup ions, and ionospheric ions are considered as particles, whereas the electrons are described as a fluid. Inhomogeneous photoionization, electron-impact ionization and charge exchange are included in our model. The temperatures of the background electrons and pickup electrons were also included into the generalized Ohm's law. We also take into account the collisions between the ions and neutrals. We use Chamberlain profiles for the exosphere's components and include a simple ionosphere model with M=28 ions that were generated inside the ionosphere. The moon is considered as a weakly conducting body. Our modeling shows that interaction between background plasma and pickup ions H+, H2+, CH4+ and N2+ has a more complicated structure than was observed in the T9 flyby and modeling due to the large gyroradius of the background O+ ions [1,2,3,4]. Special attention will be paid to comparing the simulated pickup ion velocity distribution with CAPS TA observations. We also compare our kinetic modeling with other hybrid and MHD modeling of Titan's environment. References [1] Sittler, E.C., et al., Energy Deposition Processes in Titan's Upper Atmosphere and Its Induced Magnetosphere. In: Titan from Cassini-Huygens, Brown, R.H., Lebreton J.P., Waite, J.H., Eds

  3. Characteristics of divertor heat and particle deposition with intrinsic and applied 3-D fields in NSTX H-mode plasmas

    SciTech Connect

    Ahn, J.W.; Canik, John; Maingi, Rajesh; Gray, Travis K; Lore, Jeremy D; McLean, Adam G; Park, J.-K.; Roquemore, A. L.; Soukhanovskii, V. A.

    2011-01-01

    Divertor heat and particle flux profiles are modified by externally imposed non-axisymmetric magnetic perturbations in the National Spherical Torus Experiment. The applied 3-D field causes strike point splitting that is represented as local peaks and valleys in the divertor profiles. The plasma response in an ideal perturbed equilibrium approach was included in the field line tracing by taking account of the B-field generated by the plasma current up to a certain fraction of normalized flux inside the separatrix and being superposed to the vacuum field. The inclusion of this type of plasma response does not significantly affect the location and spacing of the split strike points at the divertor surface. A modest level of divertor profile modification is found to occur even without the application of 3-D fields in certain high triangularity (delta = 0.65-0.8) discharges, with the location of local peaks and valleys same before and after the application. The intrinsic error field from the non-circularity of PF5 coil is known to have primarily n = 3 component in NSTX and was modeled to be included in the vacuum field line tracing. The produced puncture plot of the field line along with the connection length profile shows that the radial location of local peaks agrees well with the measurement, identifying intrinsic error field as a possible source of intrinsic strike point splitting. The radial location of local peaks in the profiles during the triggered ELM by the applied n = 3 field is the same before and after the 3-D field application. This shows that the heat flux from the triggered ELMs appears to follow the imposed n = 3 field structure.

  4. First steps toward 3D high resolution imaging using adaptive optics and full-field optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Blanco, Leonardo; Blavier, Marie; Glanc, Marie; Pouplard, Florence; Tick, Sarah; Maksimovic, Ivan; Chenegros, Guillaume; Mugnier, Laurent; Lacombe, Francois; Rousset, Gérard; Paques, Michel; Le Gargasson, Jean-François; Sahel, Jose-Alain

    2008-09-01

    We describe here two parts of our future 3D fundus camera coupling Adaptive Optics and full-field Optical Coherence Tomography. The first part is an Adaptive Optics flood imager installed at the Quinze-Vingts Hospital, regularly used on healthy and pathological eyes. A posteriori image reconstruction is performed, increasing the final image quality and field of view. The instrument lateral resolution is better than 2 microns. The second part is a full-field Optical Coherence Tomograph, which has demonstrated capability of performing a simple kind of "4 phases" image reconstruction of non biological samples and ex situ retinas. Final aim is to couple both parts in order to achieve 3D high resolution mapping of in vivo retinas.

  5. First MMS Observations of High Time Resolution 3D Electric and Magnetic fields at the Dayside Magnetopause.

    NASA Astrophysics Data System (ADS)

    Torbert, R. B.; Burch, J. L.; Russell, C. T.; Magnes, W.; Ergun, R. E.; Lindqvist, P. A.; Le Contel, O.; Vaith, H.; Macri, J.; Myers, S.; Rau, D.; Needell, J.; King, B.; Granoff, M.; Chutter, M.; Dors, I.; Argall, M. R.; Shuster, J. R.; Olsson, G.; Marklund, G. T.; Khotyaintsev, Y. V.; Eriksson, A. I.; Kletzing, C.; Bounds, S. R.; Anderson, B. J.; Baumjohann, W.; Steller, M.; Bromund, K. R.; Le, G.; Nakamura, R.; Strangeway, R. J.; Leinweber, H. K.; Tucker, S.; Westfall, J.; Fischer, D.; Plaschke, F.; Pollock, C. J.; Giles, B. L.; Moore, T. E.; Mauk, B.; Fuselier, S. A.

    2015-12-01

    The electrodynamics at the magnetopause is key to our understanding of ion and electron acceleration within reconnection regions. The Magnetospheric Multiscale (MMS) fleet of four spacecraft was launched into its Phase-1 equatorial orbit of 12 Re apogee specifically to investigate these regions at the Earth's magnetopause. In addition to a comprehensive suite of particle measurements, MMS makes very high time resolution 3D electric and magnetic field measurements of high accuracy using flux-gate, search coil, 3-axis double probe, and electron drift sensors. In September 2015, the MMS fleet will begin to encounter the dusk-side magnetopause in its initial configuration of approximately 160 km separation, allowing investigation of the spatial and temporal characteristics of important electrodynamics during reconnection. Using these field and particle measurements, we present first observations of 3D magnetic and electric fields (including their parallel component), and inferred current sheets, during active magnetopause crossings using the highest time resolution data available on MMS.

  6. 3D Reservoir Modeling of Semutang Gas Field: A lonely Gas field in Chittagong-Tripura Fold Belt, with Integrated Well Log, 2D Seismic Reflectivity and Attributes.

    NASA Astrophysics Data System (ADS)

    Salehin, Z.; Woobaidullah, A. S. M.; Snigdha, S. S.

    2015-12-01

    Bengal Basin with its prolific gas rich province provides needed energy to Bangladesh. Present energy situation demands more Hydrocarbon explorations. Only 'Semutang' is discovered in the high amplitude structures, where rest of are in the gentle to moderate structures of western part of Chittagong-Tripura Fold Belt. But it has some major thrust faults which have strongly breached the reservoir zone. The major objectives of this research are interpretation of gas horizons and faults, then to perform velocity model, structural and property modeling to obtain reservoir properties. It is needed to properly identify the faults and reservoir heterogeneities. 3D modeling is widely used to reveal the subsurface structure in faulted zone where planning and development drilling is major challenge. Thirteen 2D seismic and six well logs have been used to identify six gas bearing horizons and a network of faults and to map the structure at reservoir level. Variance attributes were used to identify faults. Velocity model is performed for domain conversion. Synthetics were prepared from two wells where sonic and density logs are available. Well to seismic tie at reservoir zone shows good match with Direct Hydrocarbon Indicator on seismic section. Vsh, porosity, water saturation and permeability have been calculated and various cross plots among porosity logs have been shown. Structural modeling is used to make zone and layering accordance with minimum sand thickness. Fault model shows the possible fault network, those liable for several dry wells. Facies model have been constrained with Sequential Indicator Simulation method to show the facies distribution along the depth surfaces. Petrophysical models have been prepared with Sequential Gaussian Simulation to estimate petrophysical parameters away from the existing wells to other parts of the field and to observe heterogeneities in reservoir. Average porosity map for each gas zone were constructed. The outcomes of the research

  7. Mechanisms of clay smear formation in 3D - a field study

    NASA Astrophysics Data System (ADS)

    Kettermann, Michael; Tronberens, Sebastian; Urai, Janos; Asmus, Sven

    2016-04-01

    Clay smears in sedimentary basins are important factors defining the sealing properties of faults. However, as clay smears are highly complex 3D structures, processes involved in the formation and deformation of clay smears are not well identified and understood. To enhance the prediction of sealing properties of clay smears extensive studies of these structures are necessary including the 3D information. We present extraordinary outcrop data from an open cast lignite mine (Hambach) in the Lower Rhine Embayment, Germany. The faults formed at a depth of 150 m, and have Shale Gouge Ratios between 0.1 and 0.3. Material in the fault zones is layered, with sheared sand, sheared clay and tectonically mixed sand-clay gouge. We studied the 3D thickness distribution of clay smear from a series of thin-spaced incremental cross-sections and several cross-sections in larger distances along the fault. Additionally, we excavated two large clay smear surfaces. Our observations show that clay smears are strongly affected by R- and R'-shears, mostly at the footwall side of our outcrops. These shears can locally cross and offset clay smears, forming holes. Thinnest parts of the clay smears are often located close to source layer cutoffs. Investigating the 3D thickness of the clay smears shows a heterogeneous distribution, rather than a continuous thinning of the smear with increasing distance to the source layers. We found two types of layered clay smears: one with continuous sheared sand between two clay smears providing vertical pathways for fluid flow, and one which consists of overlapping clay patches separated by sheared sand that provide a tortuous pathway across the clay smear. On smaller scale we identified grain-scale mixing as an important process for the formation of clay smears. Sand can be entrained into the clay smear by mixing from the surrounding host rock as well as due to intense shearing of sand lenses that were incorporated into the smear. This causes clay smears

  8. 3D-HST: A WIDE-FIELD GRISM SPECTROSCOPIC SURVEY WITH THE HUBBLE SPACE TELESCOPE

    SciTech Connect

    Brammer, Gabriel B.; Van Dokkum, Pieter G.; Skelton, Rosalind E.; Nelson, Erica; Bezanson, Rachel; Leja, Joel; Lundgren, Britt; Franx, Marijn; Fumagalli, Mattia; Patel, Shannon; Labbe, Ivo; Rix, Hans-Walter; Schmidt, Kasper B.; Da Cunha, Elisabete; Kriek, Mariska; Erb, Dawn K.; Fan, Xiaohui; Foerster Schreiber, Natascha; Illingworth, Garth D.; Magee, Dan; and others

    2012-06-01

    We present 3D-HST, a near-infrared spectroscopic Treasury program with the Hubble Space Telescope for studying the physical processes that shape galaxies in the distant universe. 3D-HST provides rest-frame optical spectra for a sample of {approx}7000 galaxies at 1 < z < 3.5, the epoch when {approx}60% of all star formation took place, the number density of quasars peaked, the first galaxies stopped forming stars, and the structural regularity that we see in galaxies today must have emerged. 3D-HST will cover three quarters (625 arcmin{sup 2}) of the CANDELS Treasury survey area with two orbits of primary WFC3/G141 grism coverage and two to four orbits with the ACS/G800L grism in parallel. In the IR, these exposure times yield a continuum signal-to-noise ratio of {approx}5 per resolution element at H{sub 140} {approx} 23.1 and a 5{sigma} emission-line sensitivity of {approx}5 Multiplication-Sign 10{sup -17} erg s{sup -1} cm{sup -2} for typical objects, improving by a factor of {approx}2 for compact sources in images with low sky background levels. The WFC3/G141 spectra provide continuous wavelength coverage from 1.1 to 1.6 {mu}m at a spatial resolution of {approx}0.''13, which, combined with their depth, makes them a unique resource for studying galaxy evolution. We present an overview of the preliminary reduction and analysis of the grism observations, including emission-line and redshift measurements from combined fits to the extracted grism spectra and photometry from ancillary multi-wavelength catalogs. The present analysis yields redshift estimates with a precision of {sigma}(z) = 0.0034(1 + z), or {sigma}(v) Almost-Equal-To 1000 km s{sup -1}. We illustrate how the generalized nature of the survey yields near-infrared spectra of remarkable quality for many different types of objects, including a quasar at z = 4.7, quiescent galaxies at z {approx} 2, and the most distant T-type brown dwarf star known. The combination of the CANDELS and 3D-HST surveys will

  9. Unraveling near-field and far-field relationships for 3D SERS substrates--a combined experimental and theoretical analysis.

    PubMed

    Kurouski, Dmitry; Large, Nicolas; Chiang, Naihao; Greeneltch, Nathan; Carron, Keith T; Seideman, Tamar; Schatz, George C; Van Duyne, Richard P

    2016-03-01

    Simplicity and low cost has positioned inkjet paper- and fabric-based 3D substrates as two of the most commonly used surface-enhanced Raman spectroscopy (SERS) platforms for the detection and the identification of chemical and biological analytes down to the nanogram and femtogram levels. The relationship between far-field and near-field properties of these 3D SERS platforms remains poorly understood and warrants more detailed characterization. Here, we investigate the extremely weak optical scattering observed from commercial and home-fabricated paper-, as well as fabric-based 3D SERS substrates. Using wavelength scanned surface-enhanced Raman excitation spectroscopy (WS-SERES) and finite-difference time-domain (FDTD) calculations we were able to determine their near-field SERS properties and correlate them with morphological and far-field properties. It was found that nanoparticle dimers, trimers, and higher order nanoparticle clusters primarily determine the near-field properties of these substrates. At the same time, the far-field response of 3D SERS substrates either originates primarily from the monomers or cannot be clearly defined. Using FDTD we demonstrate that LSPR bands of nanoparticle aggregates near perfectly overlap with the maxima of the near-field surface-enhanced Raman scattering responses of the 3D SERS substrates. This behaviour of far-field spectroscopic properties and near-field surface-enhanced Raman scattering has not been previously observed for 2D SERS substrates, known as nanorod arrays. The combination of these analytical approaches provides a full spectroscopic characterization of 3D SERS substrates, while FDTD simulation can be used to design new 3D SERS substrates with tailored spectral characteristics. PMID:26858996

  10. Variance Anisotropy of Solar Wind Velocity and Magnetic Field Fluctuations

    NASA Astrophysics Data System (ADS)

    Oughton, S.; Matthaeus, W. H.; Wan, M.

    2015-12-01

    At MHD scales in the solar wind, velocity and magnetic fieldfluctuations are typically observed to have much more energy in thecomponents transverse to the mean magnetic field, relative to theparallel components [eg, 1,2]. This is often referred to asvariance anisotropy. Various explanations for it have been suggested,including that the fluctuations are predominantly shear Alfvén waves[1] and that turbulent dynamics leads to such states [eg, 3].Here we investigate the origin and strength of such varianceanisotropies, using spectral method simulations of thecompressible (polytropic) 3D MHD equations. We report on results from runs with several different classes ofinitial conditions. These classes include(i) fluctuations polarized only in the same sense as shear Alfvénwaves (aka toroidal polarization),(ii) randomly polarized fluctuations, and(iii) fluctuations restricted so that most of the energy is inmodes which have their wavevectors perpendicular, or nearly so, to thebackground magnetic field: quasi-2D modes. The plasma beta and Mach number dependence [4] of quantities like the variance anisotropy, Alfven ratio, and fraction of the energy in the toroidal fluctuations will be examined, along with the timescales for the development of any systematic features.Implications for solar wind fluctuations will be discussed. References:[1] Belcher & Davis 1971, J. Geophys. Res, 76, 3534.[2] Oughton et al 2015, Phil Trans Roy Soc A, 373, 20140152.[3] Matthaeus et al 1996, J. Geophys. Res, 101, 7619.[4] Smith et al 2006, J. Geophys. Res, 111, A09111.

  11. New constraints on the 3D shear wave velocity structure of the upper mantle underneath Southern Scandinavia revealed from non-linear tomography

    NASA Astrophysics Data System (ADS)

    Wawerzinek, B.; Ritter, J. R. R.; Roy, C.

    2013-08-01

    We analyse travel times of shear waves, which were recorded at the MAGNUS network, to determine the 3D shear wave velocity (vS) structure underneath Southern Scandinavia. The travel time residuals are corrected for the known crustal structure of Southern Norway and weighted to account for data quality and pick uncertainties. The resulting residual pattern of subvertically incident waves is very uniform and simple. It shows delayed arrivals underneath Southern Norway compared to fast arrivals underneath the Oslo Graben and the Baltic Shield. The 3D upper mantle vS structure underneath the station network is determined by performing non-linear travel time tomography. As expected from the residual pattern the resulting tomographic model shows a simple and continuous vS perturbation pattern: a negative vS anomaly is visible underneath Southern Norway relative to the Baltic Shield in the east with a contrast of up to 4% vS and a sharp W-E dipping transition zone. Reconstruction tests reveal besides vertical smearing a good lateral reconstruction of the dipping vS transition zone and suggest that a deep-seated anomaly at 330-410 km depth is real and not an inversion artefact. The upper part of the reduced vS anomaly underneath Southern Norway (down to 250 km depth) might be due to an increase in lithospheric thickness from the Caledonian Southern Scandes in the west towards the Proterozoic Baltic Shield in Sweden in the east. The deeper-seated negative vS anomaly (330-410 km depth) could be caused by a temperature anomaly possibly combined with effects due to fluids or hydrous minerals. The determined simple 3D vS structure underneath Southern Scandinavia indicates that mantle processes might influence and contribute to a Neogene uplift of Southern Norway.

  12. Reinterpretation of nappe structures in the Central Alps Evidence from 3D foliation field modelling

    NASA Astrophysics Data System (ADS)

    Maxelon, M.; Mancktelow, N. S.

    2003-04-01

    The Lepontine Alps represent the classic region for both, fold nappe development at mid-crustal levels and fold interference patterns from outcrop to regional scale. They have also been proposed as models for rapid burial and exhumation. However, before such models can be applied or critically assessed, the geometry of the units involved must be accurately known in three dimensions and this is a challenging task in this complex region. The three-dimensional geometry of the Lepontine nappes is not established unequivocally, as the integration and visualisation of structural data reflecting at least five different deformation phases has not yet been achieved satisfactorily. The present study focusses on a combination of new structural mapping in critical and/or contradictory areas, existing observations and their geostatistical assessment with modern computer-based tools (Editeur Géologique, Gocad) in order to develop a testable three-dimensional model of the geometry of the Lepontine Nappes in the Central Alps. Here we present a regional-scale three dimensional model of the southern central part of the Lepontine Region, bordered by the Swiss-Italian frontier in the east and Valle Leventina to the west and by Biasca and Locarno to the north and south. The model visualises a geostatistical calculation of the dominant foliation field in three dimensions, based on field measurements. The present day tectonostratigraphy and nappe geometry are mainly influenced by the three earliest recognisable Alpine deformation phases D_1 to D_3. D_1 structures are associated with first-time crustal nappe emplacement. Lithologies that are interpreted as nappe separators - mainly Mesozoic sediments such as "Bündnerschiefer" - have mostly been interleaved between the nappes during D_1, which entails strong isoclinal folding and pronounced boudinage of the infolded lithologies, with the development of a penetrative foliation S_1. S_1 and the infolded Mesozoic have been intensely

  13. Potential Geophysical Field Transformations and Combined 3D Modelling for Estimation the Seismic Site Effects on Example of Israel

    NASA Astrophysics Data System (ADS)

    Eppelbaum, Lev; Meirova, Tatiana

    2015-04-01

    It is well-known that the local seismic site effects may have a significant contribution to the intensity of damage and destruction (e.g., Hough et al., 1990; Regnier et al., 2000; Bonnefoy-Claudet et al., 2006; Haase et al., 2010). The thicknesses of sediments, which play a large role in amplification, usually are derived from seismic velocities. At the same time, thickness of sediments may be determined (or defined) on the basis of 3D combined gravity-magnetic modeling joined with available geological materials, seismic data and borehole section examination. Final result of such investigation is a 3D physical-geological model (PGM) reflecting main geological peculiarities of the area under study. Such a combined study needs in application of a reliable 3D mathematical algorithm of computation together with advanced methodology of 3D modeling. For this analysis the developed GSFC software was selected. The GSFC (Geological Space Field Calculation) program was developed for solving a direct 3-D gravity and magnetic prospecting problem under complex geological conditions (Khesin et al., 1996; Eppelbaum and Khesin, 2004). This program has been designed for computing the field of Δg (Bouguer, free-air or observed value anomalies), ΔZ, ΔX, ΔY , ΔT , as well as second derivatives of the gravitational potential under conditions of rugged relief and inclined magnetization. The geological space can be approximated by (1) three-dimensional, (2) semi-infinite bodies and (3) those infinite along the strike closed, L.H. non-closed, R.H. on-closed and open). Geological bodies are approximated by horizontal polygonal prisms. The program has the following main advantages (besides abovementioned ones): (1) Simultaneous computing of gravity and magnetic fields; (2) Description of the terrain relief by irregularly placed characteristic points; (3) Computation of the effect of the earth-air boundary by the method of selection directly in the process of interpretation; (4

  14. A 3-D velocity structure in and around the Miura peninsula, Japan, using a 3-component off-line seismographic array.

    NASA Astrophysics Data System (ADS)

    Kawamura, T.; Hirata, N.; Sato, H.; Onishi, M.; Noda, K.; Saito, H.

    2004-12-01

    A deep seismic profiling around the Metropolitan Tokyo region, the Kanto district, started in 2002 under the project titled as the Regional Characterization of the Crust in Metropolitan Areas for Prediction of Strong Ground Motion. The deep seismic profiling, Tokyo Bay 2003, was performed along the major axis of the Tokyo Bay. Because the seismic line in the Miura peninsula passes through a densely populated area, we have a low signal-to-noise ratio data due to the cultural noise. Thus, in addition to the conventional reflection profiling, we deployed 51 off-line recorders with a 3-compornent geophone of 4.5 Hz at carefully selected, quiet receiver points. During 90 days, we had continuous records including many shot signals produced by vibrators on land and air-guns at the bay area. These data provided far-offset first arrival signals and wide angle reflections. We focus on the common receiver gather records of the Tokyo Bay 2003 off-line stations data to identify first arrival and wide angle phases. We applied the first arrival tomography method using a finite difference travel time solver (Hole, 1992) to those data to obtain a 3-D P-wave velocity structure of the uppermost crust along the profile. We obtained a velocity model in and around the Miura peninsula as follows: Across the Tokyo Bay, near surface is a layer with velocities of 2.0-2.5 km/s. A low velocity area corresponds to the fore-arc basin sediment (post Early Miocene) which extends to a depth of approximately 4 km. High velocity patches are located at a depth of approximately 6 km under the Miura peninsula, which we interpreted as Pre-Neogene basement rocks. Finally, the velocity structure obtained by the tomography analysis is used to improve the processing of the reflection profiling data to clarify the deeper structure in the peninsula, including a good velocity constraint for a pre-stack migration of the reflection profiling data.

  15. Measurements of stress fields near a grain boundary: Exploring blocked arrays of dislocations in 3D

    DOE PAGESBeta

    Guo, Y.; Collins, D. M.; Tarleton, E.; Hofmann, F.; Tischler, J.; Liu, W.; Xu, R.; Wilkinson, A. J.; Britton, T. B.

    2015-06-24

    The interaction between dislocation pile-ups and grain boundaries gives rise to heterogeneous stress distributions when a structural metal is subjected to mechanical loading. Such stress heterogeneity leads to preferential sites for damage nucleation and therefore is intrinsically linked to the strength and ductility of polycrystalline metals. To date the majority of conclusions have been drawn from 2D experimental investigations at the sample surface, allowing only incomplete observations. Our purpose here is to significantly advance the understanding of such problems by providing quantitative measurements of the effects of dislocation pile up and grain boundary interactions in 3D. This is accomplished throughmore » the application of differential aperture X-ray Laue micro-diffraction (DAXM) and high angular resolution electron backscatter diffraction (HR-EBSD) techniques. Our analysis demonstrates a similar strain characterization capability between DAXM and HR-EBSD and the variation of stress intensity in 3D reveals that different parts of the same grain boundary may have different strengths in resisting slip transfer, likely due to the local grain boundary curvature.« less

  16. Measurements of stress fields near a grain boundary: Exploring blocked arrays of dislocations in 3D

    SciTech Connect

    Guo, Y.; Collins, D. M.; Tarleton, E.; Hofmann, F.; Tischler, J.; Liu, W.; Xu, R.; Wilkinson, A. J.; Britton, T. B.

    2015-06-24

    The interaction between dislocation pile-ups and grain boundaries gives rise to heterogeneous stress distributions when a structural metal is subjected to mechanical loading. Such stress heterogeneity leads to preferential sites for damage nucleation and therefore is intrinsically linked to the strength and ductility of polycrystalline metals. To date the majority of conclusions have been drawn from 2D experimental investigations at the sample surface, allowing only incomplete observations. Our purpose here is to significantly advance the understanding of such problems by providing quantitative measurements of the effects of dislocation pile up and grain boundary interactions in 3D. This is accomplished through the application of differential aperture X-ray Laue micro-diffraction (DAXM) and high angular resolution electron backscatter diffraction (HR-EBSD) techniques. Our analysis demonstrates a similar strain characterization capability between DAXM and HR-EBSD and the variation of stress intensity in 3D reveals that different parts of the same grain boundary may have different strengths in resisting slip transfer, likely due to the local grain boundary curvature.

  17. Constructing a starting 3D shear velocity model with sharp interfaces for SEM-based upper mantle tomography in North America

    NASA Astrophysics Data System (ADS)

    Calo, M.; Bodin, T.; Yuan, H.; Romanowicz, B. A.; Larmat, C. S.; Maceira, M.

    2013-12-01

    this work we propose instead to directly tackle the non-linearity of the inverse problem by using stochastic methods to construct a 3D starting model with a good estimate of the depths of the main layering interfaces. We present preliminary results of the construction of such a starting 3D model based on: (1) Regionalizing the study area to define provinces within which lateral variations are smooth; (2) Applying trans-dimensional stochastic inversion (Bodin et al., 2012) to obtain accurate 1D models in each province as well as the corresponding error distribution, constrained by receiver function and surface wave dispersion data as well as the previously constructed 3D model (name), and (3) connecting these models laterally using data-driven smoothing operators to obtain a starting 3D model with errors. References Bodin, T.,et al. 2012, Transdimensional inversion of receiver functions and surface wave dispersion, J. Geophys. Res., 117, B02301, doi:10.1029/2011JB008560. Yuan and Romanowicz, 2013, in revison. Yuan, H., et al. 2011, 3-D shear wave radially and azimuthally anisotropic velocity model of the North American upper mantle. Geophysical Journal International, 184: 1237-1260. doi: 10.1111/j.1365-246X.2010.04901.x Yuan, H. & Romanowicz, B., 2010. Lithospheric layering in the North American Craton, Nature, 466, 1063-1068.

  18. Contribution of a 3D velocity model and of beam forming method for the location of microseismic sources generated in soft rock landslides

    NASA Astrophysics Data System (ADS)

    Provost, Floriane; Malet, Jean-Philippe; Helmstetter, Agnès; Doubre, Cécile; Gance, Julien

    2016-04-01

    Microseismicity monitoring has proven to be an important tool for a better understanding of the deformation occurring in slow-sliding landslides. However locating the seismic sources generated by a landslide remains a challenging problem due to (1) the small sizes of the landslide, (b) the heterogenous and time-changing petro-physical properties of the landslide material, (c) the complexity of the recorded signals with unclear discriminations of the wave onsets, and (d) the difficulties to install and maintain a dense seismological network on-site close to the seismic sources. We studied the seismic sources generated by the deformation of the clay-rich Super-Sauze landslide (South French Alps). Previous studies show that the most active zone is the uphill part of the landslide within a zone of 300x300m2. Two seismic antennas have been installed on the sides of this zone and a seismic campaign was conducted to build a 3D velocity model of the area. Calibration shots were performed to test the performance of the location method. We show that the use of a 3D velocity model integrated in a beam forming location method slightly improves the accuracy of the shot location epicenter. However, this approach does not help to interpret with confidence the location of the natural events because the horizontal error remains larger than 50m for more than 50% of the shots. Nevertheless, adding station corrections and constraining the grid search area with additional informations based on the signal and the landslide behavior such as SNR, seismic event typology, and surface kinematics of the landslide allow obtaining reliable results. More than 70% of the calibration shots could be located with a horizontal error of less than 40m. The lack of sensor installed in depth as well as the the lack of calibration shots realized at different depths does not permit us to identify the depth of the sources.

  19. Multi-scale Finite-Frequency Travel-time Tomography Applied to Imaging 3-D Velocity Structure of the Upper Mantle Beneath the Southwest United States

    NASA Astrophysics Data System (ADS)

    Yin, Y.; Hung, S.

    2007-12-01

    Seismic tomographic imaging has played a key component to unravel the deep processes that caused the surface morphology and rift magmatism in the southwest United States. Several studies used teleseismic body- wave arrivals recorded by the La Ristra experiment, a dense broadband array of 950-km in length deployed during 1999-2001 and run through the Great Plains, the Rio Grande Rift, and the Colorado Plateau, to construct a 2-D tomographic image of the upper mantle structure beneath this linear array (e.g., Gao et al., 2004). However, because of the inevitable smoothing and damping imposed in the tomographic model, the resulting velocity contrast is too weak to explain distinct P and S waveform changes across the array (Song and Helmberger, 2007). In this study, we include all the data from the La Ristra and available nearby arrays and reexamine finite- frequency travel time delays measured by inter-station cross correlation of waveforms at both high- (0.3-2 Hz for P and 0.1-0.5 Hz for S) and low-frequencies (0.03-0.125 Hz for P and 0.03-0.1 Hz for S). Differing from the previous models that rely on classical ray theory and simple grid parameterization, our inversion considers more realistic 3-D sensitivity kernels for relative travel-time delays and a wavelet-based, multi-scale parameterization that enables to yield robust features with spatially-varying resolutions. Our preliminary P-wave model reveals a prominent low-velocity zone extending from near surface to the depth of 300 km beneath the Rio Grande Rift, while the upper mantle which underlies the Great Plains and the Colorado Plateau is seismically fast. We will demonstrate the difference and improvement of 3-D tomographic models through the use of finite-frequency kernels and multi-scale parameterization.

  20. Using twelve years of USGS refraction lines to calibrate the Brocher and others (1997) 3D velocity model of the Bay Area

    USGS Publications Warehouse

    Boatwright, John; Blair, Luke; Catchings, Rufus; Goldman, Mark; Perosi, Fabio; Steedman, Clare

    2004-01-01

    Campbell (1983) demonstrated that site amplification correlates with depths to the 1.0, 1.5, and 2.5 km/s S-wave velocity horizons. To estimate these depths for the Bay Area stations in the PEER/NGA database, we compare the depths to the 3.2 and 4.4 km/s P-wave velocities in the Brocher and others (1997) 3D velocity model with the depths to these horizons determined from 6 refraction lines shot in the Bay Area from 1991 to 2003. These refraction lines range from two recent 20 km lines that extend from Los Gatos to downtown San Jose, and from downtown San Jose into Alum Rock Park, to two older 200 km lines than run axially from Hollister up the San Francisco Peninsula to Inverness and from Hollister up the East Bay across San Pablo Bay to Santa Rosa. Comparison of these cross-sections with the Brocher and others (1997) model indicates that the 1.5 km/s S-wave horizon, which we correlate with the 3.2 km/s P-wave horizon, is the most reliable horizon that can be extracted from the Brocher and others (1997) velocity model. We determine simple adjustments to bring the Brocher and others (1997) 3.2 and 4.4 km/s P-wave horizons into an average agreement with the refraction results. Then we apply these adjustments to estimate depths to the 1.5 and 2.5 km/s S-wave horizons beneath the strong motion stations in the PEER/NGA database.

  1. 3D galaxy clustering with future wide-field surveys: Advantages of a spherical Fourier-Bessel analysis

    NASA Astrophysics Data System (ADS)

    Lanusse, F.; Rassat, A.; Starck, J.-L.

    2015-06-01

    Context. Upcoming spectroscopic galaxy surveys are extremely promising to help in addressing the major challenges of cosmology, in particular in understanding the nature of the dark universe. The strength of these surveys, naturally described in spherical geometry, comes from their unprecedented depth and width, but an optimal extraction of their three-dimensional information is of utmost importance to best constrain the properties of the dark universe. Aims: Although there is theoretical motivation and novel tools to explore these surveys using the 3D spherical Fourier-Bessel (SFB) power spectrum of galaxy number counts Cℓ(k,k'), most survey optimisations and forecasts are based on the tomographic spherical harmonics power spectrum C(ij)_ℓ. The goal of this paper is to perform a new investigation of the information that can be extracted from these two analyses in the context of planned stage IV wide-field galaxy surveys. Methods: We compared tomographic and 3D SFB techniques by comparing the forecast cosmological parameter constraints obtained from a Fisher analysis. The comparison was made possible by careful and coherent treatment of non-linear scales in the two analyses, which makes this study the first to compare 3D SFB and tomographic constraints on an equal footing. Nuisance parameters related to a scale- and redshift-dependent galaxy bias were also included in the computation of the 3D SFB and tomographic power spectra for the first time. Results: Tomographic and 3D SFB methods can recover similar constraints in the absence of systematics. This requires choosing an optimal number of redshift bins for the tomographic analysis, which we computed to be N = 26 for zmed ≃ 0.4, N = 30 for zmed ≃ 1.0, and N = 42 for zmed ≃ 1.7. When marginalising over nuisance parameters related to the galaxy bias, the forecast 3D SFB constraints are less affected by this source of systematics than the tomographic constraints. In addition, the rate of increase of the

  2. 3D palmprint and hand imaging system based on full-field composite color sinusoidal fringe projection technique.

    PubMed

    Zhang, Zonghua; Huang, Shujun; Xu, Yongjia; Chen, Chao; Zhao, Yan; Gao, Nan; Xiao, Yanjun

    2013-09-01

    Palmprint and hand shape, as two kinds of important biometric characteristics, have been widely studied and applied to human identity recognition. The existing research is based mainly on 2D images, which lose the third-dimensional information. The biological features extracted from 2D images are distorted by pressure and rolling, so the subsequent feature matching and recognition are inaccurate. This paper presents a method to acquire accurate 3D shapes of palmprint and hand by projecting full-field composite color sinusoidal fringe patterns and the corresponding color texture information. A 3D imaging system is designed to capture and process the full-field composite color fringe patterns on hand surface. Composite color fringe patterns having the optimum three fringe numbers are generated by software and projected onto the surface of human hand by a digital light processing projector. From another viewpoint, a color CCD camera captures the deformed fringe patterns and saves them for postprocessing. After compensating for the cross talk and chromatic aberration between color channels, three fringe patterns are extracted from three color channels of a captured composite color image. Wrapped phase information can be calculated from the sinusoidal fringe patterns with high precision. At the same time, the absolute phase of each pixel is determined by the optimum three-fringe selection method. After building up the relationship between absolute phase map and 3D shape data, the 3D palmprint and hand are obtained. Color texture information can be directly captured or demodulated from the captured composite fringe pattern images. Experimental results show that the proposed method and system can yield accurate 3D shape and color texture information of the palmprint and hand shape. PMID:24085070

  3. Field observations of swash zone flow patterns and 3D morphodynamics

    USGS Publications Warehouse

    Puelo, Jack A.; Holland, K. Todd; Kooney, Timothy N.; Sallenger,, Asbury H., Jr.

    2001-01-01

    Rapid video measurements of foreshore morphology and velocity were collected at Duck, NC in 1997 to investigate sediment transport processes in the swash zone. Estimates of foreshore evolution over a roughly 30 m cross-shore by 80 m alongshore study area were determined using a stereogrammetric technique. During the passage of a small storm (offshore wave heights increased from 1.4 to 2.5 m), the foreshore eroded nearly 40 cm in less than 4 hours. Dense, horizontal surface velocities were measured over a sub-region (roughly 30 m by 40 m) of the study area using a new particle image velocimetry technique. This technique was able to quantify velocities across the bore front approaching 5 m s–1 as well as the rapid velocities in the very shallow backwash flows. The velocity and foreshore topography measurements were used to test a three-dimensional energetics-based sediment transport model. Even though these data represent the most extensive and highly resolved swash measurements to date, the results showed that while the model could predict some of the qualitative trends in the observed foreshore change, it was a poor predictor of the observed magnitudes of foreshore change. Model — data comparisons differed by roughly an order of magnitude with observed foreshore changes on the order of 10's of centimeters and model predictions on the order of meters. This poor comparison suggests that future models of swash-zone sediment transport may require the inclusion of other physical processes such as bore turbulence, fluid accelerations and skewness, infiltration/exfiltration, water depth variations, and variable friction factors (to name a few).

  4. Tangible 3D printouts of scientific data volumes with FOSS - an emerging field for research

    NASA Astrophysics Data System (ADS)

    Löwe, Peter; Klump, Jens; Wickert, Jens; Ludwig, Marcel; Frigeri, Alessandro

    2013-04-01

    Humans are very good in using both hands and eyes for tactile pattern recognition: The german verb for understanding, "begreifen" literally means "getting a (tactile) grip on a matter". This proven and time honoured concept has been in use since prehistoric times. While the amount of scientific data continues to grow, researchers still need all the support to help them visualize the data content before their inner eye. Immersive data-visualisations are helpful, yet fail to provide tactile feedback as provided from tangible objects. The need for tangible representations of geospatial information to solve real world problems eventually led to the advent of 3d-globes by M. Behaim in the 15th century and has continued since. The production of a tangible representation of a scientific data set with some fidelity is just the final step of an arc, leading from the physical world into scientific reasoning and back: The process starts with a physical observation, or a model, by a sensor which produces a data stream which is turned into a geo-referenced data set. This data is turned into a volume representation which is converted into command sequences for the printing device, leading to the creation of a 3d-printout. Finally, the new specimen has to be linked to its metadata to ensure its scientific meaning and context. On the technical side, the production of a tangible data-print has been realized as a pilot workflow based on the Free and Open Source Geoinformatics tools GRASS GIS and Paraview to convert scientific data volume into stereolithography datasets (stl) for printing on a RepRap printer. The initial motivation to use tangible representations of complex data was the task of quality assessments on tsunami simulation data sets in the FP7 TRIDEC project (www.tridec-online.eu). For this, 3d-prints of space time cubes of tsunami wave spreading patterns were produced. This was followed by print-outs of volume data derived from radar sounders (MARSIS, SHARAD) imaging

  5. 3-D solid modeling of sandstone reservoirs using NURBS: A case study of Noonen Ranch Field, Denver Basin, Colorado

    SciTech Connect

    Fisher, T.R. ); Wales, R.Q. )

    1990-02-01

    In this paper, the authors describe an experimental attempt to represent sandstone petroleum reservoirs as 3-D solids using Intergraphs object-oriented NURBS (non-uniform rational B-splines) based engineering modeling system. Initial data interpretation, well log correlation, map preparation and combination were done using GIPSE geological interpretation software. The modeling efforts were concentrated on Noonen Ranch, a small producing field in the Denver Basin of Colorado.

  6. Dynamic complex optical fields for optical manipulation, 3D microscopy, and photostimulation of neurotransmitters

    NASA Astrophysics Data System (ADS)

    Daria, Vincent R.; Stricker, Christian; Bekkers, John; Redman, Steve; Bachor, Hans

    2010-08-01

    We demonstrate a multi-functional system capable of multiple-site two-photon excitation of photo-sensitive compounds as well as transfer of optical mechanical properties on an array of mesoscopic particles. We use holographic projection of a single Ti:Sapphire laser operating in femtosecond pulse mode to show that the projected three-dimensional light patterns have sufficient spatiotemporal photon density for multi-site two-photon excitation of biological fluorescent markers and caged neurotransmitters. Using the same laser operating in continuous-wave mode, we can use the same light patterns for non-invasive transfer of both linear and orbital angular momentum on a variety of mesoscopic particles. The system also incorporates high-speed scanning using acousto-optic modulators to rapidly render 3D images of neuron samples via two-photon microscopy.

  7. Lessons in modern digital field geology: Open source software, 3D techniques, and the new world of digital mapping

    NASA Astrophysics Data System (ADS)

    Pavlis, Terry; Hurtado, Jose; Langford, Richard; Serpa, Laura

    2014-05-01

    Although many geologists refuse to admit it, it is time to put paper-based geologic mapping into the historical archives and move to the full potential of digital mapping techniques. For our group, flat map digital geologic mapping is now a routine operation in both research and instruction. Several software options are available, and basic proficiency with the software can be learned in a few hours of instruction and practice. The first practical field GIS software, ArcPad, remains a viable, stable option on Windows-based systems. However, the vendor seems to be moving away from ArcPad in favor of mobile software solutions that are difficult to implement without GIS specialists. Thus, we have pursued a second software option based on the open source program QGIS. Our QGIS system uses the same shapefile-centric data structure as our ArcPad system, including similar pop-up data entry forms and generic graphics for easy data management in the field. The advantage of QGIS is that the same software runs on virtually all common platforms except iOS, although the Android version remains unstable as of this writing. A third software option we are experimenting with for flat map-based field work is Fieldmove, a derivative of the 3D-capable program Move developed by Midland Valley. Our initial experiments with Fieldmove are positive, particularly with the new, inexpensive (<300Euros) Windows tablets. However, the lack of flexibility in data structure makes for cumbersome workflows when trying to interface our existing shapefile-centric data structures to Move. Nonetheless, in spring 2014 we will experiment with full-3D immersion in the field using the full Move software package in combination with ground based LiDAR and photogrammetry. One new workflow suggested by our initial experiments is that field geologists should consider using photogrammetry software to capture 3D visualizations of key outcrops. This process is now straightforward in several software packages, and

  8. 3D velocity structure of the outer forearc of the Colombia-Ecuador subduction zone; implications for the 1958 megathrust earthquake rupture zone

    NASA Astrophysics Data System (ADS)

    Galve, A.; Charvis, P.; Garcia Cano, L.; Marcaillou, B.

    2013-12-01

    In 2005, we conducted an onshore-offshore 3D refraction and wide-angle reflection seismic experiment over the rupture zone of the 1958 subduction earthquake that occurred near the border between Colombia and Ecuador. This earthquake was part of a sequence of 3 large ruptures (1942, Mw=7.8; 1958, Mw=7.7; 1979, Mw=8.2), which successively broke from south to north the segments of the megathrust that had been ruptured in 1906 by a single, very large magnitude (8.8) earthquake. Using first arrival traveltime inversion, we constructed a well-defined Vp velocity model of the plate boundary and of the upper and lower plates, down to 25 km depth. The model reveals a 5-km thick, low velocity zone in the upper plate, located immediately above the interplate contact. Because similar low-velocity zones are commonly observed along margins made of oceanic or island-arc accreted terranes, we suggest that the low-velocity zone might result from the alteration and hydration of mafic and ultramafic rocks in the upper plate basement, rather than from hydrofracturing alone. Sediments underplated beneath the inner wedge might contribute to the low-velocity zone but it is unlikely that they are several kilometers thick. Nevertheless, fluids expelled by the compaction and dehydration of those underplated sediments possibly favor the alteration of the overlying rocks. The low-velocity zone is spatially coincident with the 1958 rupture area. Near the toe of the margin, the model shows a low velocity gradient in the outer wedge that we interpret as a zone of highly faulted and fractured rocks or of poorly consolidated sediments. This low velocity/low gradient region forms the oceanward limit of the rupture zones of both the 1958 and the 1979 earthquakes. We suggest that the two earthquake ruptures were arrested by the low velocity zone because its low rigidity contributed to dissipate most of the seismic energy and of the coseismic strain/stress. This might be the reason why the 1958

  9. Handling and quantifying uncertainty in geological 3D models: A methodological approach based on remote-sensing and field work.

    NASA Astrophysics Data System (ADS)

    Baumberger, Roland; Wehrens, Philip; Herwegh, Marco

    2013-04-01

    Geological 3D models are always just an approximation of a complex natural situation. This is especially true in regions, where hard underground data (e.g. bore holes, tunnel mappings and seismic data) is lacking. One of the key problems while developing valid geological 3D models is the three-dimensional spatial distribution of geological structures, particularly with increasing distance from the surface. In our study, we investigate the Alpine 3D Deformation of the crystalline rocks of the Aar massif (Haslital valley, Central Switzerland). Deformation in this area is dominated by different sets of large-scale shear zones, which acted under both ductile and brittle deformation conditions. The goal of our study is the prediction of the geometry and the evolution of the structures in 3D space and time. A key point in our project is the generation of a reliable 3D model of today's structures. In this sense, estimation of the reliability of the surface information for the extrapolation to depth is mandatory. Based on our data, a method will be presented that contributes to a possible solution of the questions addressed above. The basic idea consists of the fact that (i) mechanical anisotropies as shear zones and faults show prominent three-dimensional information in the landscape, (ii) these geometries can be used as input data for a geological 3D model and (iii) that the 3D information mentioned allows a projection to depth. As a great advantage of the study area, a large number of underground tunnels exist, which allow to evaluate the quality of the aforementioned extrapolations. The method is based on a combined remote-sensing and field work approach: morphological incisions recognized on digital elevation models as well as on aerial photos on the computer screen were evaluated, described and attributed in detail in the field. Our approach is based on a six step workflow: (1) Elaboration of a large-scale structural map of geological structures by means of remote

  10. Calculation of the potentials and 3D electric fields in a proton decay detector

    SciTech Connect

    Lari, R.J.; Dawson, J.W.; Turner, L.R.

    1987-01-01

    An electrostatic detector for measuring the lifetime of the proton has been modeled in three dimensions. Linear hexahedral finite elements were used and the potential obtained at all nodes. The three components of the electric field were calculated and used to determine field lines, calculate drift fields and drift times. Effective aperture calculations agreed with the measurements.

  11. Can we trace the eastern Gondwanan margin in Australia? New perspectives from transdimensional inversion of ambient noise for 3D shear velocity structure

    NASA Astrophysics Data System (ADS)

    Pilia, S.; Rawlinson, N.; Direen, N. G.

    2013-12-01

    Although the notion of Rodinia is quite well accepted in the geoscience community, the location and nature of the eastern continental margin of the Gondwana fragment in Australia is still vague and remains one of the most hotly debated topics in Australian geology. Moreover, most post-Rodinian reconstructions models choose not to tackle the ';Tasmanian challenge', and focus only on the tectonic evolution of mainland southeast Australia, thereby conveniently ignoring the wider tectonic implications of Tasmania's complex geological history. One of the chief limitations of the tectonic reconstructions in this region is a lack of information on Paleozoic (possibly Proterozoic) basement structures. Vast Mesozoic-Cainozoic sedimentary and volcanic cover sequences obscure older outcrops and limit the power of direct observational techniques. In response to these challenges, our effort is focused on ambient seismic noise for imaging 3D crustal shear velocity structure using surface waves, which is capable of illuminating basement structure beneath younger cover. The data used in this study is sourced from the WOMBAT transportable seismic array, which is compounded by around 650 stations spanning the majority of southeastern Australia, including Tasmania and several islands in Bass Strait. To produce the highest quality Green's functions, careful processing of the data has been performed, after which group velocity dispersion measurements have been carried out using a frequency-time analysis method on the symmetric component of the empirical Green's functions (EGFs). Group dispersion measurements from the EGFs have been inverted using a novel hierarchical, transdimensional, Bayesian algorithm to obtain Rayleigh-wave group velocity maps at different periods from 2 to 30 s. The new approach has several advantages in that the number and distribution of model parameters are implicitly controlled by the data, in which the noise is treated as unknown in the inversion. This

  12. Quantification of gully volume using very high resolution DSM generated through 3D reconstruction from airborne and field digital imagery

    NASA Astrophysics Data System (ADS)

    Castillo, Carlos; Zarco-Tejada, Pablo; Laredo, Mario; Gómez, Jose Alfonso

    2013-04-01

    Major advances have been made recently in automatic 3D photo-reconstruction techniques using uncalibrated and non-metric cameras (James and Robson, 2012). However, its application on soil conservation studies and landscape feature identification is currently at the outset. The aim of this work is to compare the performance of a remote sensing technique using a digital camera mounted on an airborne platform, with 3D photo-reconstruction, a method already validated for gully erosion assessment purposes (Castillo et al., 2012). A field survey was conducted in November 2012 in a 250 m-long gully located in field crops on a Vertisol in Cordoba (Spain). The airborne campaign was conducted with a 4000x3000 digital camera installed onboard an aircraft flying at 300 m above ground level to acquire 6 cm resolution imagery. A total of 990 images were acquired over the area ensuring a large overlap in the across- and along-track direction of the aircraft. An ortho-mosaic and the digital surface model (DSM) were obtained through automatic aerial triangulation and camera calibration methods. For the field-level photo-reconstruction technique, the gully was divided in several reaches to allow appropriate reconstruction (about 150 pictures taken per reach) and, finally, the resulting point clouds were merged into a unique mesh. A centimetric-accuracy GPS provided a benchmark dataset for gully perimeter and distinguishable reference points in order to allow the assessment of measurement errors of the airborne technique and the georeferenciation of the photo-reconstruction 3D model. The uncertainty on the gully limits definition was explicitly addressed by comparison of several criteria obtained by 3D models (slope and second derivative) with the outer perimeter obtained by the GPS operator identifying visually the change in slope at the top of the gully walls. In this study we discussed the magnitude of planimetric and altimetric errors and the differences observed between the

  13. Automated bone segmentation from large field of view 3D MR images of the hip joint.

    PubMed

    Xia, Ying; Fripp, Jurgen; Chandra, Shekhar S; Schwarz, Raphael; Engstrom, Craig; Crozier, Stuart

    2013-10-21

    Accurate bone segmentation in the hip joint region from magnetic resonance (MR) images can provide quantitative data for examining pathoanatomical conditions such as femoroacetabular impingement through to varying stages of osteoarthritis to monitor bone and associated cartilage morphometry. We evaluate two state-of-the-art methods (multi-atlas and active shape model (ASM) approaches) on bilateral MR images for automatic 3D bone segmentation in the hip region (proximal femur and innominate bone). Bilateral MR images of the hip joints were acquired at 3T from 30 volunteers. Image sequences included water-excitation dual echo stead state (FOV 38.6 × 24.1 cm, matrix 576 × 360, thickness 0.61 mm) in all subjects and multi-echo data image combination (FOV 37.6 × 23.5 cm, matrix 576 × 360, thickness 0.70 mm) for a subset of eight subjects. Following manual segmentation of femoral (head-neck, proximal-shaft) and innominate (ilium+ischium+pubis) bone, automated bone segmentation proceeded via two approaches: (1) multi-atlas segmentation incorporating non-rigid registration and (2) an advanced ASM-based scheme. Mean inter- and intra-rater reliability Dice's similarity coefficients (DSC) for manual segmentation of femoral and innominate bone were (0.970, 0.963) and (0.971, 0.965). Compared with manual data, mean DSC values for femoral and innominate bone volumes using automated multi-atlas and ASM-based methods were (0.950, 0.922) and (0.946, 0.917), respectively. Both approaches delivered accurate (high DSC values) segmentation results; notably, ASM data were generated in substantially less computational time (12 min versus 10 h). Both automated algorithms provided accurate 3D bone volumetric descriptions for MR-based measures in the hip region. The highly computational efficient ASM-based approach is more likely suitable for future clinical applications such as extracting bone-cartilage interfaces for potential cartilage segmentation. PMID:24077264

  14. Automated bone segmentation from large field of view 3D MR images of the hip joint

    NASA Astrophysics Data System (ADS)

    Xia, Ying; Fripp, Jurgen; Chandra, Shekhar S.; Schwarz, Raphael; Engstrom, Craig; Crozier, Stuart

    2013-10-01

    Accurate bone segmentation in the hip joint region from magnetic resonance (MR) images can provide quantitative data for examining pathoanatomical conditions such as femoroacetabular impingement through to varying stages of osteoarthritis to monitor bone and associated cartilage morphometry. We evaluate two state-of-the-art methods (multi-atlas and active shape model (ASM) approaches) on bilateral MR images for automatic 3D bone segmentation in the hip region (proximal femur and innominate bone). Bilateral MR images of the hip joints were acquired at 3T from 30 volunteers. Image sequences included water-excitation dual echo stead state (FOV 38.6 × 24.1 cm, matrix 576 × 360, thickness 0.61 mm) in all subjects and multi-echo data image combination (FOV 37.6 × 23.5 cm, matrix 576 × 360, thickness 0.70 mm) for a subset of eight subjects. Following manual segmentation of femoral (head-neck, proximal-shaft) and innominate (ilium+ischium+pubis) bone, automated bone segmentation proceeded via two approaches: (1) multi-atlas segmentation incorporating non-rigid registration and (2) an advanced ASM-based scheme. Mean inter- and intra-rater reliability Dice's similarity coefficients (DSC) for manual segmentation of femoral and innominate bone were (0.970, 0.963) and (0.971, 0.965). Compared with manual data, mean DSC values for femoral and innominate bone volumes using automated multi-atlas and ASM-based methods were (0.950, 0.922) and (0.946, 0.917), respectively. Both approaches delivered accurate (high DSC values) segmentation results; notably, ASM data were generated in substantially less computational time (12 min versus 10 h). Both automated algorithms provided accurate 3D bone volumetric descriptions for MR-based measures in the hip region. The highly computational efficient ASM-based approach is more likely suitable for future clinical applications such as extracting bone-cartilage interfaces for potential cartilage segmentation.

  15. Modeling Recent Large Earthquakes Using the 3-D Global Wave Field

    NASA Astrophysics Data System (ADS)

    Hjörleifsdóttir, V.; Kanamori, H.; Tromp, J.

    2003-04-01

    We use the spectral-element method (SEM) to accurately compute waveforms at periods of 40 s and longer for three recent large earthquakes using 3D Earth models and finite source models. The M_w~7.6, Jan~26, 2001, Bhuj, India event had a small rupture area and is well modeled at long periods with a point source. We use this event as a calibration event to investigate the effects of 3-D Earth models on the waveforms. The M_w~7.9, Nov~11, 2001, Kunlun, China, event exhibits a large directivity (an asymmetry in the radiation pattern) even at periods longer than 200~s. We used the source time function determined by Kikuchi and Yamanaka (2001) and the overall pattern of slip distribution determined by Lin et al. to guide the wave-form modeling. The large directivity is consistent with a long fault, at least 300 km, and an average rupture speed of 3±0.3~km/s. The directivity at long periods is not sensitive to variations in the rupture speed along strike as long as the average rupture speed is constant. Thus, local variations in rupture speed cannot be ruled out. The rupture speed is a key parameter for estimating the fracture energy of earthquakes. The M_w~8.1, March~25, 1998, event near the Balleny Islands on the Antarctic Plate exhibits large directivity in long period surface waves, similar to the Kunlun event. Many slip models have been obtained from body waves for this earthquake (Kuge et al. (1999), Nettles et al. (1999), Antolik et al. (2000), Henry et al. (2000) and Tsuboi et al. (2000)). We used the slip model from Henry et al. to compute SEM waveforms for this event. The synthetic waveforms show a good fit to the data at periods from 40-200~s, but the amplitude and directivity at longer periods are significantly smaller than observed. Henry et al. suggest that this event comprised two subevents with one triggering the other at a distance of 100 km. To explain the observed directivity however, a significant amount of slip is required between the two subevents

  16. Precise Animated 3-D Displays Of The Heart Constructed From X-Ray Scatter Fields

    NASA Astrophysics Data System (ADS)

    McInerney, J. J.; Herr, M. D.; Copenhaver, G. L.

    1986-01-01

    A technique, based upon the interrogation of x-ray scatter, has been used to construct precise animated displays of the three-dimensional surface of the heart throughout the cardiac cycle. With the selection of motion amplification, viewing orientation, beat rate, and repetitive playbacks of isolated segments of the cardiac cycle, these displays are used to directly visualize epicardial surface velocity and displacement patterns, to construct regional maps of old or new myocardial infarction, and to visualize diastolic stiffening of the ventricle associated with acute ischemia. The procedure is non-invasive. Cut-downs or injections are not required.

  17. Tomographic reconstruction of circularly polarized high-harmonic fields: 3D attosecond metrology

    PubMed Central

    Chen, Cong; Tao, Zhensheng; Hernández-García, Carlos; Matyba, Piotr; Carr, Adra; Knut, Ronny; Kfir, Ofer; Zusin, Dimitry; Gentry, Christian; Grychtol, Patrik; Cohen, Oren; Plaja, Luis; Becker, Andreas; Jaron-Becker, Agnieszka; Kapteyn, Henry; Murnane, Margaret

    2016-01-01

    Bright, circularly polarized, extreme ultraviolet (EUV) and soft x-ray high-harmonic beams can now be produced using counter-rotating circularly polarized driving laser fields. Although the resulting circularly polarized harmonics consist of relatively simple pairs of peaks in the spectral domain, in the time domain, the field is predicted to emerge as a complex series of rotating linearly polarized bursts, varying rapidly in amplitude, frequency, and polarization. We extend attosecond metrology techniques to circularly polarized light by simultaneously irradiating a copper surface with circularly polarized high-harmonic and linearly polarized infrared laser fields. The resulting temporal modulation of the photoelectron spectra carries essential phase information about the EUV field. Utilizing the polarization selectivity of the solid surface and by rotating the circularly polarized EUV field in space, we fully retrieve the amplitude and phase of the circularly polarized harmonics, allowing us to reconstruct one of the most complex coherent light fields produced to date. PMID:26989782

  18. Tomographic Reconstruction of Circularly Polarized High Harmonic Fields: 3D Attosecond Metrology

    NASA Astrophysics Data System (ADS)

    Chen, Cong; Tao, Zhensheng; Hernández-García, Carlos; Matyba, Piotr; Carr, Adra; Knut, Ronny; Kfir, Ofer; Zusin, Dimitry; Gentry, Christian; Grychtol, Patrick; Cohen, Oren; Plaja, Lius; Becker, Andreas; Jaron-Becker, Agnieszka; Kapteyn, Henry; Murnane, Margaret

    Bright, circularly polarized, extreme ultraviolet (EUV) and soft X-ray high harmonic beams can now be produced using counter-rotating circularly polarized driving laser fields. In the time domain, the field is predicted to emerge as a complex series of rotating linearly polarized bursts, varying rapidly in amplitude, frequency and polarization. Here, we extend attosecond metrology techniques to circularly polarized light for the first time by simultaneously irradiating a copper surface with circularly polarized high harmonic and linearly polarized infrared laser fields. The resulting temporal modulation of the photoelectron spectra carries essential phase information about the EUV field. Utilizing the polarization selectivity of the solid surface and by rotating the circularly polarized EUV field in space, we fully retrieve the amplitude and phase of the circularly polarized harmonics, allowing us to reconstruct one of the most complex coherent light fields produced to date.

  19. Can symmetry transitions of complex fields enable 3-d control of fluid vorticity?

    SciTech Connect

    Martin, James E.; Solis, Kyle Jameson

    2015-08-01

    Methods of inducing vigorous noncontact fluid flow are important to technologies involving heat and mass transfer and fluid mixing, since they eliminate the need for moving parts, pipes and seals, all of which compromise system reliability. Unfortunately, traditional noncontact flow methods are few, and have limitations of their own. We have discovered two classes of fields that can induce fluid vorticity without requiring either gravity or a thermal gradient. The first class we call Symmetry-Breaking Rational Fields. These are triaxial fields comprised of three orthogonal components, two ac and one dc. The second class is Rational Triad Fields, which differ in that all three components are alternating. In this report we quantify the induced vorticity for a wide variety of fields and consider symmetry transitions between these field types. These transitions give rise to orbiting vorticity vectors, a technology for non-contact, non-stationary fluid mixing.

  20. Assessing soil water storage distribution under sprinkler irrigation by coupling 3D simulations and field observations

    NASA Astrophysics Data System (ADS)

    Taha, Uday; Shabeeb, Ahmed; dragonetti, giovanna; Lamaddalena, Nicola; Coppola, Antonio

    2016-04-01

    This work analyzed the variability of sprinkler irrigation application over a bare soil, both in terms of water application efficiency and uniformity, by integrating and comparing the information on the irrigation depth data (ID), as measured by catch cans, soil water storage in the upper root zone, as measured by TDR probes, and a 3D simulations of water flow in soils. Three irrigation tests were performed at three different pressures (2, 3 and 4 bar). A lateral water redistribution was observed and simulated after each irrigation event by comparing spatial distributions of site-specific water application efficiency (AEs), as well as ratios of site-specific actual water storage increase (SWEs) and irrigation depth (IDs) to the water content before irrigation. Because of soil water redistribution processes, distribution uniformity based on soil storages was systematically higher than the catch can uniformity. The obvious consequence of lateral water redistribution processes was that the soil smoothing action on non-uniformity observed at the surface increased both with depth and over time. At a given depth the uniformity of soil water storages always attained the same value, whatever the pressure considered and the catch can-based uniformity coefficient. It was concluded that, for the case of random distribution of ID, the uniformity of water storages is driven by the soil behavior rather than by the irrigation system.

  1. Self-Sensing, Ultralight, and Conductive 3D Graphene/Iron Oxide Aerogel Elastomer Deformable in a Magnetic Field.

    PubMed

    Xu, Xiang; Li, Hui; Zhang, Qiangqiang; Hu, Han; Zhao, Zongbin; Li, Jihao; Li, Jingye; Qiao, Yu; Gogotsi, Yury

    2015-04-28

    Three-dimensional (3D) graphene aerogels (GA) show promise for applications in supercapacitors, electrode materials, gas sensors, and oil absorption due to their high porosity, mechanical strength, and electrical conductivity. However, the control, actuation, and response properties of graphene aerogels have not been well studied. In this paper, we synthesized 3D graphene aerogels decorated with Fe3O4 nanoparticles (Fe3O4/GA) by self-assembly of graphene with simultaneous decoration by Fe3O4 nanoparticles using a modified hydrothermal reduction process. The aerogels exhibit up to 52% reversible magnetic field-induced strain and strain-dependent electrical resistance that can be used to monitor the degree of compression/stretching of the material. The density of Fe3O4/GA is only about 5.8 mg cm(-3), making it an ultralight magnetic elastomer with potential applications in self-sensing soft actuators, microsensors, microswitches, and environmental remediation. PMID:25792130

  2. 3D-resolved fluorescence and phosphorescence lifetime imaging using temporal focusing wide-field two-photon excitation

    PubMed Central

    Choi, Heejin; Tzeranis, Dimitrios S.; Cha, Jae Won; Clémenceau, Philippe; de Jong, Sander J. G.; van Geest, Lambertus K.; Moon, Joong Ho; Yannas, Ioannis V.; So, Peter T. C.

    2012-01-01

    Fluorescence and phosphorescence lifetime imaging are powerful techniques for studying intracellular protein interactions and for diagnosing tissue pathophysiology. While lifetime-resolved microscopy has long been in the repertoire of the biophotonics community, current implementations fall short in terms of simultaneously providing 3D resolution, high throughput, and good tissue penetration. This report describes a new highly efficient lifetime-resolved imaging method that combines temporal focusing wide-field multiphoton excitation and simultaneous acquisition of lifetime information in frequency domain using a nanosecond gated imager from a 3D-resolved plane. This approach is scalable allowing fast volumetric imaging limited only by the available laser peak power. The accuracy and performance of the proposed method is demonstrated in several imaging studies important for understanding peripheral nerve regeneration processes. Most importantly, the parallelism of this approach may enhance the imaging speed of long lifetime processes such as phosphorescence by several orders of magnitude. PMID:23187477

  3. The global velocity field of the filament in NGC 6334

    NASA Astrophysics Data System (ADS)

    Zernickel, A.; Schilke, P.; Smith, R. J.

    2013-06-01

    Aims: Star formation involves the collapse of gas from the scale of giant molecular clouds down to dense cores. Our aim is to trace the velocities in the filamentary, massive star-forming region NGC 6334 and to explain its dynamics. Methods: The main filament was mapped with the single-dish telescope APEX in HCO+ (J = 3-2) at 267.6 GHz to trace the dense gas. In order to reproduce the position-velocity diagram, we use a 3D radiative transfer code and create a model of a cylinder that undergoes a gravitational collapse toward its center. Results: We find a velocity gradient in the filament from the end toward its center, with the highest masses being found at both ends. Similar velocities have been predicted by recent calculations of the gravitational collapse of a sheet or cylinder of gas, and the observed velocities are consistent with these predictions. The 3D structure is revealed by taking the inclination and curvature of the filament into account. The free-fall collapse timescale of the filamentary molecular cloud is estimated to be ~1 Myr. This publication is based on data acquired with the Atacama Pathfinder Experiment (APEX). APEX is a collaboration between the Max-Planck-Institut für Radioastronomie, the European Southern Observatory, and the Onsala Space Observatory.

  4. 3D Analysis of Wake Field Excitation in a Dielectric Loaded Rectangular Resonator

    SciTech Connect

    Sotnikov, Gennadij V.; Onishchenko, Ivan N.; Marshall, Thomas C.

    2006-11-27

    The results of a three-dimensional analysis of wake field excitation in a slab-symmetric dielectric-loaded resonator by rigid electron bunches are presented. The complete set of solutions, including the solenoidal and potential parts of the electromagnetic field, consists of LSM and LSE modes. Each of the LSM and LSE modes contains odd and even waves. A numerical analysis of wake field excitation by symmetric electron bunches is carried out. The three-dimensional spatial structure of the longitudinal electric field is investigated. The influence of the drift vacuum channel on the wake field amplitude and on the coherent summation of wakefields for a regular sequence of bunches is studied.

  5. A Detailed 3D Seismic Velocity Structure of the Subducting Pacific Slab Beneath Hokkaido, Tohoku and Kanto, Japan, by Double-Difference Tomography

    NASA Astrophysics Data System (ADS)

    Tsuji, Y.; Nakajima, J.; Kita, S.; Okada, T.; Matsuzawa, T.; Hasegawa, A.

    2007-12-01

    Three-dimensional heterogeneous structure beneath northeastern (NE) Japan has been investigated by previous studies and an inclined seismic low-velocity zone is imaged in the mantle wedge sub-parallel to the down-dip direction of the subducting slab (Zhao et al., 1992, Nakajima et al., 2001). However, the heterogeneous structure within the slab has not been well studied even though it is very important to understand the whole process of water transportation from the slab to the surface. Here we show a detailed 3D seismic velocity structure within the subducted Pacific slab around Japan and propose a water-transportation path from the slab to the mantle wedge. In this study, we estimated 3D velocity structure within the Pacific slab by the double-difference tomography (Zhang and Thurber, 2003). We divided the study area, from Hokkaido to Kanto, into 6 areas due to the limitation of memory and computation time. In each area, arrival-time data of 7,500-17,000 events recorded at 70-170 stations were used in the analysis. The total number of absolute travel-time data was about 140,000-312,000 for P wave and 123,000-268,000 for S wave, and differential data were about 736,000-1,920,000 for P wave and 644,000-1,488,000 for S wave. Horizontal and vertical grid separations are 10-25 km and 6.5 km, respectively. RMS residuals of travel times for P wave decreased from 0.23s to 0.09s and for S wave from 0.35s to 0.13s. The obtained results are as follows: (1) a remarkable low-Vs zone exists in the uppermost part of the subducting slab, (2) it extends down to a depth of about 80 km, (3) the termination of this low-Vs zone almost corresponds to the "seismic belt" recently detected in the upper plane of the double seismic zone (Kita et al.,2006; Hasegawa et al., 2007), (4) at depths deeper than 80 km, a low-Vs and high-Vp/Vs zone is apparently distributed in the mantle wedge, immediately above the slab crust. We consider that these features reflect water-transportation processes

  6. Wave Phase-Sensitive Transformation of 3d-Straining of Mechanical Fields

    NASA Astrophysics Data System (ADS)

    Smirnov, I. N.; Speranskiy, A. A.

    2015-11-01

    It is the area of research of oscillatory processes in elastic mechanical systems. Technical result of innovation is creation of spectral set of multidimensional images which reflect time-correlated three-dimensional vector parameters of metrological, and\\or estimated, and\\or design parameters of oscillations in mechanical systems. Reconstructed images of different dimensionality integrated in various combinations depending on their objective function can be used as homeostatic profile or cybernetic image of oscillatory processes in mechanical systems for an objective estimation of current operational conditions in real time. The innovation can be widely used to enhance the efficiency of monitoring and research of oscillation processes in mechanical systems (objects) in construction, mechanical engineering, acoustics, etc. Concept method of vector vibrometry based on application of vector 3D phase- sensitive vibro-transducers permits unique evaluation of real stressed-strained states of power aggregates and loaded constructions and opens fundamental innovation opportunities: conduct of continuous (on-line regime) reliable monitoring of turboagregates of electrical machines, compressor installations, bases, supports, pipe-lines and other objects subjected to damaging effect of vibrations; control of operational safety of technical systems at all the stages of life cycle including design, test production, tuning, testing, operational use, repairs and resource enlargement; creation of vibro-diagnostic systems of authentic non-destructive control of anisotropic characteristics of materials resistance of power aggregates and loaded constructions under outer effects and operational flaws. The described technology is revolutionary, universal and common for all branches of engineering industry and construction building objects.

  7. Slipher, Galaxies, and Cosmological Velocity Fields

    NASA Astrophysics Data System (ADS)

    Peacock, J. A.

    2013-04-01

    By 1917, V. M. Slipher had singlehandedly established a general tendency for ‘spiral nebulae’ to be redshifted (21 out of 25 cases). From a modern perspective, it could seem surprising that the discovery of the expansion of the universe was not announced at this point. Examination of the data and arguments contained in Slipher's papers shows that he reached a more subtle conclusion: the identification of cosmological peculiar velocities, including the bulk motion of the Milky Way, leading to a beautiful argument in favor of spiral nebulae as distant stellar systems. Nevertheless, Slipher's data actually contain evidence at >8σ for a positive mean velocity, even after subtracting the best-fitting dipole pattern owing to motion of the observer. In 1929, Hubble provided distance estimates for a sample of no greater depth, using redshifts due almost entirely to Slipher. Hubble's distances turned out to be flawed in two distinct ways: in addition to an incorrect absolute calibration, the largest distances were systematically under-estimated. Nevertheless, he claimed the detection of a linear distance-redshift relation. Statistically, the evidence for such a correlation is less strong than the simple evidence for a positive mean velocity in Hubble's sample. Comparison with modern data shows that a sample of more than twice Hubble's depth would generally be required in order to reveal clearly the global linear expansion in the face of the ‘noise’ from peculiar velocities. When the theoretical context of the time is examined, the role of the de Sitter model and its prediction of a linear distance-redshift relation looms large. A number of searches for this relation were performed prior to Hubble over the period 1924-1928, with a similar degree of success. All were based on the velocities measured by Slipher, whose work from a Century ago stands out both for the precision of his measurements and for the subtle clarity of the arguments he employed to draw correct

  8. 3-D modeling of water balance and soil erosion in a clayey subsurface drained agricultural field in boreal climate

    NASA Astrophysics Data System (ADS)

    Turunen, M.; Warsta, L.; Koivusalo, H. J.; Paasonen-Kivekäs, M.; Nurminen, J.; Myllys, M.; Alakukku, L.; Äijö, H.; Puustinen, M.

    2012-12-01

    Fluxes of nutrients and other substances from cultivated fields cause eutrophication and deterioration of water quality in aquatic ecosystems worldwide. In order to develop effective strategies to control the environmental impacts of crop cultivation, it is crucial to identify the main transport pathways and the effects of different water management methods on the loads. Reduction of sediment loads is essential since sediment particles typically carry nutrients (especially sorbed phosphorus) and other potentially harmful substances, e.g. pesticides, from the fields to the adjacent surface waters. The novel part of this study was the investigation of suspended sediment transport in soil macropores to the subsurface drains and to the deep groundwater. We applied a 3-D distributed dual-permeability model (FLUSH) using a dataset collected from a subsurface drained, clayey agricultural field (15 ha) to holistically assess water balance, soil erosion and sediment transport from the field to an adjacent stream. The data set included five years of hydrological and water quality measurements from four intensively monitored field sections with different soil properties, topography, drainage systems (drain spacing and drain depth), drain installation methods (trenchless and trench drainage) and drain envelope materials (gravel and fiber). The 3-D model allowed us to quantify how soil erosion and sediment transport differed between the field sections within the field area. The simulations were conducted during snow- and frost-free periods. The simulation results include closure of water balance of the cultivated field, distribution of soil erosion and sediment transport within the field area and the effects of different subsurface drainage systems on sediment loads. The 3-D dual-permeability subsurface flow model was able to reproduce the measured drainflows and sediment fluxes in the clayey field and according to the simulations over 90% of drainflow waters were conveyed to

  9. 3-D RPIC Simulations of Relativistic Jets: Particle Acceleration, Magnetic Field Generation, and Emission

    NASA Technical Reports Server (NTRS)

    Nishikawa, K.-I.; Mizuno, Y.; Hardee, P.; Hededal, C. B.; Fishman, G. J.

    2006-01-01

    Recent PIC simulations using injected relativistic electron-ion (electro-positron) jets into ambient plasmas show that acceleration occurs in relativistic shocks. The Weibel instability created in shocks is responsible for particle acceleration, and generation and amplification of highly inhomogeneous, small-scale magnetic fields. These magnetic fields contribute to the electron's transverse deflection in relativistic jets. The "jitter" radiation from deflected electrons has different properties than the synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understand the complex time evolution and spectral structure in relativistic jets and gamma-ray bursts. We will present recent PIC simulations which show particle acceleration and magnetic field generation. We will also calculate associated self-consistent emission from relativistic shocks.

  10. 3-D Magnetic Field Analysis of Permanent Magnet Motor Considering Magnetizing, Demagnetizing and Eddy Current Loss

    NASA Astrophysics Data System (ADS)

    Miyata, Koji; Aoyama, Yasuaki; Yokoyama, Tomonori; Ohashi, Ken; Kondo, Minoru; Matsuoka, Koichi

    Rare-earth magnets, which have high energy product, have been widely used in several industrial applications such as voice coil motors for hard disk drives, MRI for medical devices and motors for electric vehicle. In order to realize a small and high performance device, the magnetic field analysis techniques are required. In this paper, we applied the magnetic field analysis to design the permanent magnet synchronous motors into the rail traction system. In the inverter fed motor drive, the eddy current loss in the permanent magnet increased. We simulated the effect that eddy current was decreased by using a divided permanent magnet. Furthermore, the permanent magnet tends to be demagnetized due to the effect of a demagnetizing field formed at high temperatures. However, according to our analysis, demagnetization does not occur within the range of our design specifications. Also, we performed magnetic field analysis assuming a pulse-type magnetization process and designed an optimal magnetizing coil.

  11. Rapid 3-D forward modeling of gravity and gravity gradient tensor fields

    NASA Astrophysics Data System (ADS)

    Longwei, C.; Dai, S.; Zhang, Q.

    2014-12-01

    Three-dimensional inversion are the key process in gravity exploration. In the commonly used scheme of inversion, the subsurface of the earth is usually divided into many small prism blocks (or grids) with variable density values. A key task in gravity inversion is to calculate the composite fields (gravity and gravity gradient tensor) generated by all these grids, this is known as forward modeling. In general forward modeling is memory-demanding and time-consuming. One scheme to rapidly calculate the fields is to implement it in Fourier domain and use fast Fourier transform algorithm. The advantage of the Fourier domain method is, obviously, much faster. However, the intrinsic edge effect of the Fourier domain method degrades the precision of the calculated fields. We have developed an innovative scheme to directly calculate the fields in spatial domain. There are two key points in this scheme. One key point is spatial discretization. Spatial convolution formula is discretized using an approach similar to normal difference method. A key idea during discretization is to use the analytical formula of a cubic prism, and this makes the resultant discrete formula have clear physical meaning: it embodies the superposition principle of the fields and is the exact formula to calculate the fields generated by all grids. The discretization only requires the grids have the same dimension in horizontal directions, and grids in different layers may have different dimension in vertical direction, and this offers more flexibility for inversion. Another key point is discrete convolution calculation. We invoke a high efficient two-dimensional discrete convolution algorithm, and it guarantees both time-saving and memory-saving. Its memory cost has the same order as the number of grids. Numerical test result shows that for a model with a dimension of 1000x1000x201 grids, it takes about 300s to calculate the fields on 1000x1000 field points in a personal computer with 3.4-GHz CPU

  12. Binary 3-D Markov Chain Random Fields: Finite-size Scaling Analysis of Percolation Properties

    NASA Astrophysics Data System (ADS)

    Harter, T.

    2004-12-01

    Percolation phenomena in random media have been extensively studied in a wide variety of fields in physics, chemistry, engineering, bio-, earth-, and environmental sciences. Most work has focused on uncorrelated random fields. The critical behavior in media with short-range correlations is thought to be identical to that in uncorrelated systems. However, the percolation threshold, pc, which is 0.3116 in uncorrelated media, has been observed to vary with the correlation scale and also with the random field type. Here, we present percolation properties and finite-size scaling effects in three-dimensional binary cubic lattices represented by correlated Markov-chain random fields and compare them to those in sequential Gaussian and sequential indicator random fields. We find that the computed percolation threshold in correlated random fields is significantly lower than in the uncorrelated lattice and decreases with increasing correlation scale. The rate of decrease rapidly flattens out for correlation lengths larger than 2-3 grid-blocks. At correlation scales of 5-6 grid blocks, pc is found to be 0.126 for the Markov chain random fields and slightly higher for sequential Gaussian and indicator random fields. The universal scaling constants for mean cluster size, backbone fraction, and connectivity are found to be consistent with results on uncorrelated lattices. For numerical studies, it is critical to understand finite-size effects on the percolation and associated phase connectivity properties of lattices. We present detailed statistical results on the percolation properties in finite sized lattice and their dependence on correlation scale. We show that appropriate grid resolution and choice of simulation boundaries is critical to properly simulate correlated natural geologic systems, which may display significant finite-size effects.

  13. Dynamically Self-consistent Simulations of the 3D Gravity and Magnetic Fields to be Measured by Juno at Jupiter

    NASA Astrophysics Data System (ADS)

    Glatzmaier, G.

    2013-12-01

    In 2016 NASA's Juno spacecraft will begin making high fidelity gravity and magnetic measurements near the surface of Jupiter that will provide clues to Jupiter's internal structure and dynamics. To prepare for the interpretation of these data, we are producing 3D dynamo simulations that self-consistently solve for the gravity and magnetic fields throughout the interior and exterior of our simulated gas giant. Knowing the trajectories of the 34 11-day polar orbits Juno will make around Jupiter as Jupiter rotates, we calculate the three components of the gravity and magnetic fields that Juno would measure as a function of time for two different simulated giant planet dynamos: one having latitudinally banded zonal winds that exist only in a shallow surface layer and one with banded zonal winds that extend deep below the surface. The different dynamo solutions are obtained by making different specifications for poorly known quantities, like the amplitude and radial dependence of the effective viscous diffusivity within Jupiter. By identifying fundamental differences in the 3D data that Juno would collect for these two scenarios, we will provide a dynamically self-consistent test for inferring the structure and amplitude of the zonal winds in Jupiter's interior. For example, a latitudinally banded pattern of magnetic field measured by Juno would suggest that strong zonal winds extend well below the surface to where the electrical conductivity is high enough for the generation of Jupiter's magnetic field.

  14. Magnetic fields end-face effect investigation of HTS bulk over PMG with 3D-modeling numerical method

    NASA Astrophysics Data System (ADS)

    Qin, Yujie; Lu, Yiyun

    2015-09-01

    In this paper, the magnetic fields end-face effect of high temperature superconducting (HTS) bulk over a permanent magnetic guideway (PMG) is researched with 3D-modeling numerical method. The electromagnetic behavior of the bulk is simulated using finite element method (FEM). The framework is formulated by the magnetic field vector method (H-method). A superconducting levitation system composed of one rectangular HTS bulk and one infinite long PMG is successfully investigated using the proposed method. The simulation results show that for finite geometrical HTS bulk, even the applied magnetic field is only distributed in x-y plane, the magnetic field component Hz which is along the z-axis can be observed interior the HTS bulk.

  15. 3-D seismic over the Fausse Pointe Field: A case history of acquisition in a harsh environment

    SciTech Connect

    Duncan, P.M.; Nester, D.C.; Martin, J.A.; Moles, J.R.

    1995-12-31

    A 50 square mile 3D seismic survey was successfully acquired over Fausse Point Field in the latter half of 1994. The geophysical and logistical challenges of this project were immense. The steep dips and extensive range of target depths required a large shoot area with a relatively fine sampling interval. The surface, while essentially flat, included areas of cane field, crawfish ponds, thick brush, swamp, open lakes and deep canals -- all typical of southern Louisiana. Planning and permitting of the survey began in late 1993. Field operations began in June 1994 and were complete in January 1995. Field personnel numbered 150 at the peak of operations. More than 19,000 crew hours were required to complete the job at a cost of over 5,000,000. The project was complete on time and on budget. The resulting images of the salt dome and surrounding rocks are not only beautiful but are revealing many opportunities for new hydrocarbon development.

  16. Dosimetric Comparison Between Intensity-Modulated with Coplanar Field and 3D Conformal Radiotherapy with Noncoplanar Field for Postocular Invasion Tumor

    SciTech Connect

    Tu Wenyong; Liu Lu Zeng Jun; Yin Weidong; Li Yun

    2010-07-01

    This study presents a dosimetric optimization effort aiming to compare noncoplanar field (NCF) on 3 dimensions conformal radiotherapy (3D-CRT) and coplanar field (CF) on intensity-modulated radiotherapy (IMRT) planning for postocular invasion tumor. We performed a planning study on the computed tomography data of 8 consecutive patients with localized postocular invasion tumor. Four fields NCF 3D-CRT in the transverse plane with gantry angles of 0-10 deg., 30-45 deg., 240-270 deg., and 310-335 deg. degrees were isocentered at the center of gravity of the target volume. The geometry of the beams was determined by beam's eye view. The same constraints were prepared with between CF IMRT optimization and NCF 3D-CRT treatment. The maximum point doses (D max) for the different optic pathway structures (OPS) with NCF 3D-CRT treatment should differ in no more than 3% from those with the NCF IMRT plan. Dose-volume histograms (DVHs) were obtained for all targets and organ at risk (OAR) with both treatment techniques. Plans with NCF 3D-CRT and CF IMRT constraints on target dose in homogeneity were computed, as well as the conformity index (CI) and homogeneity index (HI) in the target volume. The PTV coverage was optimal with both NCF 3D-CRT and CF IMRT plans in the 8 tumor sites. No difference was noted between the two techniques for the average D{sub max} and D{sub min} dose. NCF 3D-CRT and CF IMRT will yield similar results on CI. However, HI was a significant difference between NCF 3D-CRT and CF IMRT plan (p < 0.001). Physical endpoints for target showed the mean target dose to be low in the CF IMRT plan, caused by a large target dose in homogeneity (p < 0.001). The impact of NCF 3D-CRT versus CF IMRT set-up is very slight. NCF3D-CRT is one of the treatment options for postocular invasion tumor. However, constraints for OARs are needed.

  17. Pipe3D, a pipeline to analyze Integral Field Spectroscopy Data: II. Analysis sequence and CALIFA dataproducts

    NASA Astrophysics Data System (ADS)

    Sánchez, S. F.; Pérez, E.; Sánchez-Blázquez, P.; García-Benito, R.; Ibar