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Sample records for multiple kinematic edges

  1. Distinguishing dark matter stabilization symmetries using multiple kinematic edges and cusps

    SciTech Connect

    Agashe, Kaustubh; Kim, Doojin; Toharia, Manuel; Walker, Devin G. E.

    2010-07-01

    We emphasize that the stabilizing symmetry for dark matter (DM) particles does not have to be the commonly used parity (Z{sub 2}) symmetry. We therefore examine the potential of the colliders to distinguish models with parity stabilized DM from models in which the DM is stabilized by other symmetries. We often take the latter to be a Z{sub 3} symmetry for illustration. We focus on signatures where a single particle, charged under the DM stabilization symmetry decays into the DM and standard model (SM) particles. Such a Z{sub 3}-charged mother particle can decay into one or two DM particles along with the same SM particles. This can be contrasted with the decay of a Z{sub 2}-charged mother particle, where only one DM particle appears. Thus, if the intermediate particles in these decay chains are off-shell, then the reconstructed invariant mass of the SM particles exhibits two kinematic edges for the Z{sub 3} case but only one for the Z{sub 2} case. For the case of on-shell intermediate particles, distinguishing the two symmetries requires more than the kinematic edges. In this case, we note that certain decay chain topologies of the mother particle which are present for the Z{sub 3} case (but absent for the Z{sub 2} case) generate a cusp in the invariant mass distribution of the SM particles. We demonstrate that this cusp is generally invariant of the various spin configurations. We further apply these techniques within the context of explicit models.

  2. Edge-driven microplate kinematics

    USGS Publications Warehouse

    Schouten, Hans; Klitgord, Kim D.; Gallo, David G.

    1993-01-01

    It is known from plate tectonic reconstructions that oceanic microplates undergo rapid rotation about a vertical axis and that the instantaneous rotation axes describing the microplate's motion relative to the bounding major plates are frequently located close to its margins with those plates, close to the tips of propagating rifts. We propose a class of edge-driven block models to illustrate how slip across the microplate margins, block rotation, and propagation of rifting may be related to the relative motion of the plates on either side. An important feature of these edge-driven models is that the instantaneous rotation axes are always located on the margins between block and two bounding plates. According to those models the pseudofaults or traces of disrupted seafloor resulting from the propagation of rifting between microplate and major plates may be used independently to approximately trace the continuous kinematic evolution of the microplate back in time. Pseudofault geometries and matching rotations of the Easter microplate show that for most of its 5 m.y. history, block rotation could be driven by the drag of the Nazca and Pacific plates on the microplate's edges rather than by a shear flow of mantle underneath.

  3. Dissecting new physics models through kinematic edges

    NASA Astrophysics Data System (ADS)

    Iyer, Abhishek M.; Maitra, Ushoshi

    2017-02-01

    Kinematic edges in the invariant mass distributions of different final state particles are typically a signal of new physics. In this work we propose a scenario wherein these edges could be utilized in discriminating between different classes of models. To this effect, we consider the resonant production of a heavy Higgs like resonance (H1) as a case study. Such states are a characteristic feature of many new physics scenarios beyond the standard model (SM). In the event of a discovery, it is essential to identify the true nature of the underlying theory. In this work we propose a channel, H1→t2t , where t2 is a vectorlike gauge singlet top-partner that decays into W b , Z t , h t . Invariant mass distributions constructed out of these final states are characterized by the presence of kinematic edges, which are unique to the topology under consideration. Further, since all the final state particles are SM states, the position in the edges of these invariant mass distributions can be used to exclusively determine the masses of the resonances. Observation of these features are meant to serve as a trigger, thereby mandating a more detailed analysis in a particular direction of parameter space. The absence of these edge like features, in the specific invariant mass distributions considered here, in minimal versions of supersymmetric models (MSSM) also serves as a harbinger of such non-MSSM-like scenarios.

  4. GNSS Precise Kinematic Positioning for Multiple Kinematic Stations Based on A Priori Distance Constraints.

    PubMed

    He, Kaifei; Xu, Tianhe; Förste, Christoph; Petrovic, Svetozar; Barthelmes, Franz; Jiang, Nan; Flechtner, Frank

    2016-04-01

    When applying the Global Navigation Satellite System (GNSS) for precise kinematic positioning in airborne and shipborne gravimetry, multiple GNSS receiving equipment is often fixed mounted on the kinematic platform carrying the gravimetry instrumentation. Thus, the distances among these GNSS antennas are known and invariant. This information can be used to improve the accuracy and reliability of the state estimates. For this purpose, the known distances between the antennas are applied as a priori constraints within the state parameters adjustment. These constraints are introduced in such a way that their accuracy is taken into account. To test this approach, GNSS data of a Baltic Sea shipborne gravimetric campaign have been used. The results of our study show that an application of distance constraints improves the accuracy of the GNSS kinematic positioning, for example, by about 4 mm for the radial component.

  5. GNSS Precise Kinematic Positioning for Multiple Kinematic Stations Based on A Priori Distance Constraints

    PubMed Central

    He, Kaifei; Xu, Tianhe; Förste, Christoph; Petrovic, Svetozar; Barthelmes, Franz; Jiang, Nan; Flechtner, Frank

    2016-01-01

    When applying the Global Navigation Satellite System (GNSS) for precise kinematic positioning in airborne and shipborne gravimetry, multiple GNSS receiving equipment is often fixed mounted on the kinematic platform carrying the gravimetry instrumentation. Thus, the distances among these GNSS antennas are known and invariant. This information can be used to improve the accuracy and reliability of the state estimates. For this purpose, the known distances between the antennas are applied as a priori constraints within the state parameters adjustment. These constraints are introduced in such a way that their accuracy is taken into account. To test this approach, GNSS data of a Baltic Sea shipborne gravimetric campaign have been used. The results of our study show that an application of distance constraints improves the accuracy of the GNSS kinematic positioning, for example, by about 4 mm for the radial component. PMID:27043580

  6. Kinematically redundant arm formulations for coordinated multiple arm implementations

    NASA Technical Reports Server (NTRS)

    Bailey, Robert W.; Quiocho, Leslie J.; Cleghorn, Timothy F.

    1990-01-01

    Although control laws for kinematically redundant robotic arms were presented as early as 1969, redundant arms have only recently become recognized as viable solutions to limitations inherent to kinematically sufficient arms. The advantages of run-time control optimization and arm reconfiguration are becoming increasingly attractive as the complexity and criticality of robotic systems continues to progress. A generalized control law for a spatial arm with 7 or more degrees of freedom (DOF) based on Whitney's resolved rate formulation is given. Results from a simulation implementation utilizing this control law are presented. Furthermore, results from a two arm simulation are presented to demonstrate the coordinated control of multiple arms using this formulation.

  7. Loops and multiple edges in modularity maximization of networks

    NASA Astrophysics Data System (ADS)

    Cafieri, Sonia; Hansen, Pierre; Liberti, Leo

    2010-04-01

    The modularity maximization model proposed by Newman and Girvan for the identification of communities in networks works for general graphs possibly with loops and multiple edges. However, the applications usually correspond to simple graphs. These graphs are compared to a null model where the degree distribution is maintained but edges are placed at random. Therefore, in this null model there will be loops and possibly multiple edges. Sharp bounds on the expected number of loops, and their impact on the modularity, are derived. Then, building upon the work of Massen and Doye, but using algebra rather than simulation, we propose modified null models associated with graphs without loops but with multiple edges, graphs with loops but without multiple edges and graphs without loops nor multiple edges. We validate our models by using the exact algorithm for clique partitioning of Grötschel and Wakabayashi.

  8. TWO-DIMENSIONAL KINEMATICS OF THE EDGE-ON SPIRAL GALAXY ESO 379-006

    SciTech Connect

    Rosado, M.; Gabbasov, R. F.; Repetto, P.; Martos, M.; Fuentes-Carrera, I.; Amram, P.; Hernandez, O.

    2013-05-15

    We present a kinematical study of the nearly edge-on galaxy ESO 379-006 that shows the existence of extraplanar ionized gas. With Fabry-Perot spectroscopy at H{alpha}, we study the kinematics of ESO 379-006 using velocity maps and position-velocity diagrams parallel to the major and to the minor axis of the galaxy. We build the rotation curve of the disk and discuss the role of projection effects due to the fact of viewing this galaxy nearly edge-on. The twisting of the isovelocities in the radial velocity field of the disk of ESO 379-006 as well as the kinematical asymmetries found in some position-velocity diagrams parallel to the minor axis of the galaxy suggest the existence of deviations to circular motions in the disk that can be modeled and explained with the inclusion of a radial inflow probably generated by a bar or by spiral arms. We succeeded in detecting extraplanar diffuse ionized gas in this galaxy. At the same time, from the analysis of position-velocity diagrams, we found some evidence that the extraplanar gas could lag in rotation velocity with respect to the midplane rotation.

  9. Orbital kinematics of edge-on bars with and without supermassive black holes

    NASA Astrophysics Data System (ADS)

    Abbott, Caleb; Valluri, Monica; Shen, Juntai; Debattista, Victor P.

    2016-01-01

    Observations of external disk galaxies with bars frequently show boxy or peanut shaped bulges, which have a distinct X-shaped structure when the system is viewed edge-on. Such features are also well documented in N-body simulations, where they arise from the buckling of the bar. The precise nature of the orbits that create this structure is still uncertain. Some studies argue that the bulge/X-shape structure is formed and supported by resonant 2:1 "banana" orbit family, while other argue that they arise from 5:3 "brezel" orbits. Here we examine a set of N-body models of a barred disk galaxy (with and without a central black hole). We generate 2-D maps of projected kinematics both for specific orbit families as well as the full simulation of the bars at different orientations. By examining the line-of-sight velocities, velocity dispersions and 3rd and 4th Gauss-Hermite polynomials we attempt to deduce the type of orbits most likely to produce the X-shaped features. We also generate mock kinematics for the Milky Way bar and predict the kinematical features associated with the X-shape that will be observed with upcoming stellar surveys.

  10. Quantitative Analysis Of Sperm Motion Kinematics From Real-Time Video-Edge Images

    NASA Astrophysics Data System (ADS)

    Davis, Russell O...; Katz, David F.

    1988-02-01

    A new model of sperm swimming kinematics, which uses signal processing methods and multivariate statistical techniques to identify individual cell-motion parameters and unique cell populations, is presented. Swimming paths of individual cells are obtained using real-time, video-edge digitization. Raw paths are adaptively filtered to identify average paths, and measurements of space-time oscillations about average paths are made. Time-dependent frequency information is extracted from spatial variations about average paths using harmonic analysis. Raw-path and average-path measures such as curvature, curve length, and straight-line length, and measures of oscillations about average paths such as time-dependent amplitude and frequency variations, are used in a multivariate, cluster analysis to identify unique cell populations. The entire process, including digitization of sperm video images, is computer-automated. Preliminary results indicate that this method of tracking, digitization, and kinematic analysis accurately identifies unique cell subpopulations, including: the relative numbers of cells in each subpopulation, how subpopulations differ, and the extent and significance of such differences. With appropriate work, this approach may be useful for clinical discrimination between normal and abnormal semen specimens.

  11. Spectral CT Using Multiple Balanced K-Edge Filters

    PubMed Central

    Rakvongthai, Yothin; Worstell, William; Fakhri, Georges El; Bian, Junguo; Lorsakul, Auranuch; Ouyang, Jinsong

    2015-01-01

    Our goal is to validate a spectral CT system design that uses a conventional X-ray source with multiple balanced K-edge filters. By performing a simultaneously synthetic reconstruction in multiple energy bins, we obtained a good agreement between measurements and model expectations for a reasonably complex phantom. We performed simulation and data acquisition on a phantom containing multiple rods of different materials using a NeuroLogica CT scanner. Five balanced K-edge filters including Molybdenum, Cerium, Dysprosium, Erbium, and Tungsten were used separately proximal to the X-ray tube. For each sinogram bin, measured filtered vector can be defined as a product of a transmission matrix, which is determined by the filters and is independent of the imaging object, and energy-binned intensity vector. The energy-binned sinograms were then obtained by inverting the transmission matrix followed by a multiplication of the filter measurement vector. For each energy bin defined by two consecutive K-edges, a synthesized energy-binned attenuation image was obtained using filtered back-projection reconstruction. The reconstructed attenuation coefficients for each rod obtained from the experiment was in good agreement with the corresponding simulated results. Furthermore, the reconstructed attenuation coefficients for a given energy bin, agreed with National Institute of Standards and Technology reference values when beam hardening within the energy bin is small. The proposed cost-effective system design using multiple balanced K-edge filters can be used to perform spectral CT imaging at clinically relevant flux rates using conventional detectors and integrating electronics. PMID:25252276

  12. Geomorphic signal of active faulting at the northern edge of Lut Block: Insights on the kinematic scenario of Central Iran

    NASA Astrophysics Data System (ADS)

    Calzolari, Gabriele; Della Seta, Marta; Rossetti, Federico; Nozaem, Reza; Vignaroli, Gianluca; Cosentino, Domenico; Faccenna, Claudio

    2016-01-01

    Recent works documented Neogene to Quaternary dextral strike-slip tectonics along the Kuh-e-Sarhangi and Kuh-e-Faghan intraplate strike-slip faults at the northern edge of the Lut Block of Central Iran, previously thought to be dominated by sinistral strike-slip deformation. This work focuses on the evidence of Quaternary activity of one of these fault systems, in order to provide new spatiotemporal constraints on their role in the active regional kinematic scenario. Through geomorphological and structural investigation, integrated with optically stimulated luminescence dating of three generations of alluvial fans and fluvial terraces (at ~53, ~25, and ~6 ka), this study documents (i) the topographic inheritance of the long-term (Myr) punctuated history of fault nucleation, propagation, and exhumation along the northern edge of Lut Block; (ii) the tectonic control on drainage network evolution, pediment formation, fluvial terraces, and alluvial fan architecture; (iii) the minimum Holocene age of Quaternary dextral strike-slip faulting; and (iv) the evidence of Late Quaternary fault-related uplift localized along the different fault strands. The documented spatial and temporal constraints on the active dextral strike-slip tectonics at the northern edge of Lut Block provide new insights on the kinematic model for active faulting in Central Iran, which has been reinterpreted in an escape tectonic scenario.

  13. Evidence for edge effects on multiple levels in tallgrass prairie

    USGS Publications Warehouse

    Winter, M.; Johnson, D.H.; Faaborg, J.

    2000-01-01

    We tested how edges affect nest survival and predator distribution in a native tallgrass prairie system in southwestern Missouri using artificial nests, natural nests of Dickcissels (Spiza americana) and Henslow's Sparrows (Ammodramus henslowii), and mammal track stations. Survival of artificial nests was lower within 30 m of forest edge. Nesting success of Dickcissels and Henslow's Sparrows was lower within 50 m to a shrubby edge than at greater distances, whereas fates of nests were not related to distances to roads, agricultural fields, or forests. Evidence from clay eggs placed in artificial nests indicated that mid-sized carnivores were the major predators within 30 m of forest edges. Furthermore, mid-sized carnivores visited track stations most frequently within 50 m of forest edges. Because proximity of woody habitat explained more variation in nest survival and mammal activity than did fragment size, it appears that edge effects were more pronounced than area effects. Edge effects appeared to be caused mainly by greater exposure of nests to midsized carnivores. We argue that, based on edge avoidance behavior, 'grassland-interior' species such as the Henslow's Sparrow respond to edge effects mainly by a decrease in density, whereas habitat generalists such as the Dickcissel are affected mainly by a decrease in nesting success.

  14. Motor abundance contributes to resolving multiple kinematic task constraints

    PubMed Central

    G, Gera; SMSF, Freitas; ML, Latash; K, Monahan; G, Schöner; JP, Scholz

    2009-01-01

    This study investigated the use of motor abundance during the transport and placing of objects that required either precise or minimal orientation to the target. Analyses across repetitions of the structure of joint configuration variance relative to the position and orientation constraints were performed using the Uncontrolled Manifold (UCM) approach. Results indicated that the orientation constraint did not affect stability of the hand's spatial trajectory. Orientation was weakly stabilized during the late transport phase independent of the orientation constraint, indicating no default synergy stabilizing orientation. Stabilization of orientation for conditions most requiring it for successful insertion of the object was present primarily during the adjustment phase. The results support the hypothesis that a major advantage of a control scheme that utilizes motor abundance is the ability to resolve multiple task constraints simultaneously without undue interference among them. PMID:20237405

  15. KRISTINA: Kinematic rib-based structural system for innovative adaptive trailing edge

    NASA Astrophysics Data System (ADS)

    Pecora, R.; Amoroso, F.; Magnifico, M.; Dimino, I.; Concilio, A.

    2016-04-01

    Nature teaches that the flight of the birds succeeds perfectly since they are able to change the shape of their wings in a continuous manner. The careful observation of this phenomenon has re-introduced in the recent research topics the study of "metamorphic" wing structures; these innovative architectures allow for the controlled wing shape adaptation to different flight conditions with the ultimate goal of getting desirable improvements such as the increase of aerodynamic efficiency or load control effectiveness. In this framework, the European research project SARISTU aimed at combining morphing and smart ideas to the leading edge, the trailing edge and the winglet of a large commercial airplane (EASA CS25 category) while assessing integrated technologies validation through high-speed wind tunnel test on a true scale outer wing segment. The design process of the adaptive trailing edge (ATED) addressed by SARISTU is here outlined, from the conceptual definition of the camber-morphing architecture up to the assessment of the device executive layout. Rational design criteria were implemented in order to preliminarily define ATED structural layout and the general configuration of the embedded mechanisms enabling morphing under the action of aerodynamic loads. Advanced FE analyses were then carried out and the robustness of adopted structural arrangements was proven in compliance with applicable airworthiness requirements.

  16. Adaptive synchronised tracking control for multiple robotic manipulators with uncertain kinematics and dynamics

    NASA Astrophysics Data System (ADS)

    Zhao, Dongya; Li, Shaoyuan; Zhu, Quanmin

    2016-03-01

    In this study, a new adaptive synchronised tracking control approach is developed for the operation of multiple robotic manipulators in the presence of uncertain kinematics and dynamics. In terms of the system synchronisation and adaptive control, the proposed approach can stabilise position tracking of each robotic manipulator while coordinating its motion with the other robotic manipulators. On the other hand, the developed approach can cope with kinematic and dynamic uncertainties. The corresponding stability analysis is presented to lay a foundation for theoretical understanding of the underlying issues as well as an assurance for safely operating real systems. Illustrative examples are bench tested to validate the effectiveness of the proposed approach. In addition, to face the challenging issues, this study provides an exemplary showcase with effectively to integrate several cross boundary theoretical results to formulate an interdisciplinary solution.

  17. Effect of rhythmic auditory stimulation on gait kinematic parameters of patients with multiple sclerosis

    PubMed Central

    Shahraki, M; Sohrabi, M; Taheri Torbati, HR; Nikkhah, K; NaeimiKia, M

    2017-01-01

    Purpose: This study aimed to examine the effect of rhythmic auditory stimulation on gait kinematic parameters of patients with multiple sclerosis. Subjects and Methods: In this study, 18 subjects, comprising 4 males and 14 females with Multiple Sclerosis with expanded disability status scale of 3 to 6 were chosen. Subjects were selected by available and targeted sampling and were randomly divided into two experimental (n = 9) and control (n = 9) groups. Exercises were gait with rhythmic auditory stimulation by a metronome device, in addition to gait without stimulation for the experimental and control groups, respectively. Training was carried out for 3 weeks, with 30 min duration for each session 3 times a week. Stride length, stride time, double support time, cadence and gait speed were measured by motion analysis device. Results: There was a significant difference between stride length, stride time, double support time, cadence and gait speed in the experimental group, before and after the training. Furthermore, there was a significant difference between the experimental and control groups in the enhancement of stride length, stride time, cadence and gait speed in favor of the experimental group. While this difference was not significant for double support time. Conclusion: The results of this study showed that rhythmic auditory stimulation is an effective rehabilitation method to improve gait kinematic parameters in patients with multiple sclerosis. PMID:28255373

  18. Fast Algorithm and Application of Wavelet Multiple-scale Edge Detection Filter

    NASA Astrophysics Data System (ADS)

    Liang, Likai; Yang, Min; Tong, Qiang; Zhang, Yue

    This paper focuses on the algorithm theory of the two-dimensional wavelet transform which is used for image edge detection. To simplify the algorithm, the author propounds to turn the two-dimensional dyadic wavelet to one dimensional dyadic wavelet that can be divided into product. We can use the filter to achieve the wavelet multiple scale edge detection quickly. Simultaneously, the process that the wavelet transform used for the multiple-scale edge detection is discussed in detail. Finally, the algorithm can be applied to vehicle license image detection and. Compared with the results of the Sobel, Canny and the others, this algorithm shows great feasibility and the effectiveness.

  19. The Relative Kinematics of Galaxy Emission and Multiple Gas Phases in z~0.5 Extended Galaxy Halos

    NASA Astrophysics Data System (ADS)

    Churchill, Chris

    2014-02-01

    We request two nights to use the ESI echellette to obtain spatially resolved emission-line spectra for 20 intermediate redshift galaxies in support of our Cycle-21 NASA/HST COS program (110 orbits). We aim to understand the all-important gas cycles of galaxies by undertaking the first comprehensive campaign directly comparing the multi-phase gas kinematics, chemical enrichment, and spatial geometry of the circumgalactic medium (gaseous halos) to the kinematics, morphologies, star formation rates, and metallicities of the host galaxies. The unique, unprecedented, detailed scope of our program will provide highly sought observational constraints on cutting-edge galaxy evolution theory and hydrodynamic cosmological simulations.

  20. Execution Time Optimization Analysis on Multiple Algorithms Performance of Moving Object Edge Detection

    NASA Astrophysics Data System (ADS)

    Islam, Syed Zahurul; Islam, Syed Zahidul; Jidin, Razali; Ali, Mohd. Alauddin Mohd.

    2010-06-01

    Computer vision and digital image processing comprises varieties of applications, where some of these used in image processing include convolution, edge detection as well as contrast enhancement. This paper analyzes execution time optimization analysis between Sobel and Canny image processing algorithms in terms of moving objects edge detection. Sobel and Canny edge detection algorithms have been described with pseudo code and detailed flow chart and implemented in C and MATLAB respectively on different platforms to evaluate performance and execution time for moving cars. It is shown that Sobel algorithm is very effective in case of moving multiple cars and blurs images with efficient execution time. Moreover, convolution operation of Canny takes 94-95% time of total execution time with thin and smooth but redundant edges. This also makes more robust of Sobel to detect moving cars edges.

  1. Bore-Sight Calibration of Multiple Laser Range Finders for Kinematic 3D Laser Scanning Systems.

    PubMed

    Jung, Jaehoon; Kim, Jeonghyun; Yoon, Sanghyun; Kim, Sangmin; Cho, Hyoungsig; Kim, Changjae; Heo, Joon

    2015-05-04

    The Simultaneous Localization and Mapping (SLAM) technique has been used for autonomous navigation of mobile systems; now, its applications have been extended to 3D data acquisition of indoor environments. In order to reconstruct 3D scenes of indoor space, the kinematic 3D laser scanning system, developed herein, carries three laser range finders (LRFs): one is mounted horizontally for system-position correction and the other two are mounted vertically to collect 3D point-cloud data of the surrounding environment along the system's trajectory. However, the kinematic laser scanning results can be impaired by errors resulting from sensor misalignment. In the present study, the bore-sight calibration of multiple LRF sensors was performed using a specially designed double-deck calibration facility, which is composed of two half-circle-shaped aluminum frames. Moreover, in order to automatically achieve point-to-point correspondences between a scan point and the target center, a V-shaped target was designed as well. The bore-sight calibration parameters were estimated by a constrained least squares method, which iteratively minimizes the weighted sum of squares of residuals while constraining some highly-correlated parameters. The calibration performance was analyzed by means of a correlation matrix. After calibration, the visual inspection of mapped data and residual calculation confirmed the effectiveness of the proposed calibration approach.

  2. Multichannel surface EMG based estimation of bilateral hand kinematics during movements at multiple degrees of freedom.

    PubMed

    Muceli, Silvia; Jiang, Ning; Farina, Dario

    2010-01-01

    The paper proposes a method to estimate wrist kinematics from surface EMG signals for proportional and simultaneous control of multiple degrees of freedom (DOFs). The approach is based on the concurrent detection of surface EMG signals from forearm muscles and hand kinematics of both limbs during mirrored bilateral movements in free space which involve the simultaneous activation of wrist flexion/extension, radial/ulnar deviation and forearm pronation/supination. The estimation was based on one multilayer perceptron (MLP) neural network for each DOF. The three MLPs were trained to estimate angular displacements corresponding to the three DOFs. The average coefficient of determination between the true and the predicted angular displacement was 82.7 ± 2.9% (80.9 ± 3.4%) for flexion/extension, 75.0 ± 3.8% (72.6 ± 9.4%) for radial/ulnar deviation, 76.6 ± 11.8% (75.1 ± 11.7%) for pronation/supination for the ipsi-lateral (contra-lateral) hand. The scheme represents a step forward towards the simultaneous control of DOFs and thus a more natural prosthetic control.

  3. Bore-Sight Calibration of Multiple Laser Range Finders for Kinematic 3D Laser Scanning Systems

    PubMed Central

    Jung, Jaehoon; Kim, Jeonghyun; Yoon, Sanghyun; Kim, Sangmin; Cho, Hyoungsig; Kim, Changjae; Heo, Joon

    2015-01-01

    The Simultaneous Localization and Mapping (SLAM) technique has been used for autonomous navigation of mobile systems; now, its applications have been extended to 3D data acquisition of indoor environments. In order to reconstruct 3D scenes of indoor space, the kinematic 3D laser scanning system, developed herein, carries three laser range finders (LRFs): one is mounted horizontally for system-position correction and the other two are mounted vertically to collect 3D point-cloud data of the surrounding environment along the system’s trajectory. However, the kinematic laser scanning results can be impaired by errors resulting from sensor misalignment. In the present study, the bore-sight calibration of multiple LRF sensors was performed using a specially designed double-deck calibration facility, which is composed of two half-circle-shaped aluminum frames. Moreover, in order to automatically achieve point-to-point correspondences between a scan point and the target center, a V-shaped target was designed as well. The bore-sight calibration parameters were estimated by a constrained least squares method, which iteratively minimizes the weighted sum of squares of residuals while constraining some highly-correlated parameters. The calibration performance was analyzed by means of a correlation matrix. After calibration, the visual inspection of mapped data and residual calculation confirmed the effectiveness of the proposed calibration approach. PMID:25946627

  4. Medium to Long Range Kinematic GPS Positioning with Position-Velocity-Acceleration Model Using Multiple Reference Stations.

    PubMed

    Hong, Chang-Ki; Park, Chi Ho; Han, Joong-hee; Kwon, Jay Hyoun

    2015-07-13

    In order to obtain precise kinematic global positioning systems (GPS) in medium to large scale networks, the atmospheric effects from tropospheric and ionospheric delays need to be properly modeled and estimated. It is also preferable to use multiple reference stations to improve the reliability of the solutions. In this study, GPS kinematic positioning algorithms are developed for the medium to large-scale network based on the position-velocity-acceleration model. Hence, the algorithm can perform even in cases where the near-constant velocity assumption does not hold. In addition, the estimated kinematic accelerations can be used for the airborne gravimetry. The proposed algorithms are implemented using Kalman filter and are applied to the in situ airborne GPS data. The performance of the proposed algorithms is validated by analyzing and comparing the results with those from reference values. The results show that reliable and comparable solutions in both position and kinematic acceleration levels can be obtained using the proposed algorithms.

  5. Edge effects in graphene nanostructures: From multiple reflection expansion to density of states

    NASA Astrophysics Data System (ADS)

    Wurm, Jürgen; Richter, Klaus; Adagideli, Inanç

    2011-08-01

    We study the influence of different edge types on the electronic density of states of graphene nanostructures. To this end we develop an exact expansion for the single-particle Green’s function of ballistic graphene structures in terms of multiple reflections from the system boundary, which allows for a natural treatment of edge effects. We first apply this formalism to calculate the average density of states of graphene billiards. While the leading term in the corresponding Weyl expansion is proportional to the billiard area, we find that the contribution that usually scales with the total length of the system boundary differs significantly from what one finds in semiconductor-based, Schrödinger-type billiards: The latter term vanishes for armchair and infinite-mass edges and is proportional to the zigzag edge length, highlighting the prominent role of zigzag edges in graphene. We then compute analytical expressions for the density of states oscillations and energy levels within a trajectory-based semiclassical approach. We derive a Dirac version of Gutzwiller’s trace formula for classically chaotic graphene billiards and further obtain semiclassical trace formulas for the density of states oscillations in regular graphene cavities. We find that edge-dependent interference of pseudospins in graphene crucially affects the quantum spectrum.

  6. Design and analysis of rotor systems with multiple trailing edge flaps and resonant actuators

    NASA Astrophysics Data System (ADS)

    Kim, Jun-Sik

    The purpose of this thesis is to develop piezoelectric resonant actuation systems and new active control methods utilizing the multiple trailing-edge flaps' configuration for rotorcraft vibration suppression and blade loads control. An aeroelastic model is developed for a composite rotor blade with multiple trailing-edge flaps. The rotor blade airloads are calculated using quasi-steady blade element aerodynamics with a free wake model for rotor inflow. A compressible unsteady aerodynamics model is employed to accurately predict the incremental trailing edge flap airloads. Both the finite wing effect and actuator saturation for trailing-edge flaps are also included in an aeroelastic analysis. For a composite articulated rotor, a new active blade loads control method is developed and tested numerically. The concept involves straightening the blade by introducing dual trailing edge flaps. The objective function, which includes vibratory hub loads, bending moment harmonics and active flap control inputs, is minimized by an integrated optimal control/optimization process. A numerical simulation is performed for the steady-state forward flight of an advance ratio of 0.35. It is demonstrated that through straightening the rotor blade, which mimics the behavior of a rigid blade, both the bending moments and vibratory hub loads can be significantly reduced by 32% and 57%, respectively. An active vibration control method is developed and analyzed for a hingeless rotor. The concept involves deflecting each individual trailing-edge flap using a compact resonant actuation system. Each resonant actuation system could yield high authority, while operating at a single frequency. Parametric studies are conducted to explore the finite wing effect of trailing-edge flaps and actuator saturation. A numerical simulation has been performed for the steady-state forward flight (mu = 0.15 ˜ 0.35). It is demonstrated that multiple trailing-edge flap configuration with the resonant actuation

  7. Excitonic localization at macrostep edges in AlGaN/AlGaN multiple quantum wells

    NASA Astrophysics Data System (ADS)

    Hou, Mengjun; Qin, Zhixin; Zhang, Lisheng; Han, Tianyang; Wang, Mingxing; Xu, Fujun; Wang, Xinqiang; Yu, Tongjun; Fang, Zheyu; Shen, Bo

    2017-04-01

    Double peaks at wavelength of 276 and 290 nm are observed for AlGaN/AlGaN multiple quantum wells (MQWs). Cathodoluminescence (CL) mappings identify that the emission at 290 nm originates from the macrostep edges. Potential minima induced by local variation of QW thickness and Ga incorporation are found along the step edges, where quantum wires (QWRs) are formed. The lateral advance rate of macrostep (∼310 nm/h) is obtained by investigating the distribution of QWRs. Temperature-dependent CL spectrum suggest that thermal quenching for 290 nm emission is dramatically suppressed compared with that for conventional QWs emission, which shows excitonic localization characteristics of QWRs.

  8. Inaccuracy in the treatment of multiple-order diffraction by secondary-edge-source methods.

    PubMed

    Summers, Jason E

    2013-06-01

    Existing secondary-edge-source methods based on the Biot-Tolstoy solution for diffraction from an infinite wedge compute multiple-order diffraction by cascading the integration over secondary sources used to determine first-order diffraction from the edge. It is demonstrated here that this approach errs in some important cases because it neglects slope-diffraction contributions. This error is illustrated by considering the case of an infinite slit in a thin, hard screen. Comparisons with measurements for this case and analytical solutions for the case of a circular aperture in a thin, hard screen are used as a basis to gauge the magnitude of the error.

  9. A Study of Optical Edge Enhancement with Incoherent Light and Electronic Edge Enhancement as a Possible Visual Prothesis for Multiple Sclerosis Patients.

    DTIC Science & Technology

    The purpose of this investigation is to study the effects of multiple sclerosis on the human visual system and perform a preliminary analysis for a...electronic edge enhancement. Multiple sclerosis subjects were tested along with a controlled group for visual acuity improvement. It is hoped this

  10. Distance statistics in quadrangulations with no multiple edges and the geometry of minbus

    NASA Astrophysics Data System (ADS)

    Bouttier, J.; Guitter, E.

    2010-05-01

    We present a detailed calculation of the distance-dependent two-point function for quadrangulations with no multiple edges. Various discrete observables measuring this two-point function are computed and analyzed in the limit of large maps. For large distances and in the scaling regime, we recover the same universal scaling function as for general quadrangulations. We then explore the geometry of §§lsquo§§§minimal neck baby universes§§rsquo§§§ (minbus), which are the outgrowths to be removed from a general quadrangulation to transform it into a quadrangulation with no multiple edges, the §§lsquo§§§mother universe§§rsquo§§§. We give a number of distance-dependent characterizations of minbus, such as the two-point function inside a minbu or the law for the distance from a random point to the mother universe.

  11. Medium to Long Range Kinematic GPS Positioning with Position-Velocity-Acceleration Model Using Multiple Reference Stations

    PubMed Central

    Hong, Chang-Ki; Park, Chi Ho; Han, Joong-hee; Kwon, Jay Hyoun

    2015-01-01

    In order to obtain precise kinematic global positioning systems (GPS) in medium to large scale networks, the atmospheric effects from tropospheric and ionospheric delays need to be properly modeled and estimated. It is also preferable to use multiple reference stations to improve the reliability of the solutions. In this study, GPS kinematic positioning algorithms are developed for the medium to large-scale network based on the position-velocity-acceleration model. Hence, the algorithm can perform even in cases where the near-constant velocity assumption does not hold. In addition, the estimated kinematic accelerations can be used for the airborne gravimetry. The proposed algorithms are implemented using Kalman filter and are applied to the in situ airborne GPS data. The performance of the proposed algorithms is validated by analyzing and comparing the results with those from reference values. The results show that reliable and comparable solutions in both position and kinematic acceleration levels can be obtained using the proposed algorithms. PMID:26184215

  12. POSSIBLE STELLAR STREAMS IN THE EDGE-ON SPIRAL NGC 891 DISCOVERED FROM KINEMATICS OF PLANETARY NEBULAE

    SciTech Connect

    Shih, Hsin-Yi; Mendez, Roberto H. E-mail: mendez@ifa.hawaii.ed

    2010-12-10

    We have found 125 planetary nebulae (PNs) in NGC 891, using an [O III] {lambda}5007 on-band/off-band filter technique with the Faint Object Camera and Spectrograph (FOCAS) at the Cassegrain focus of the Subaru telescope, Mauna Kea. Radial velocities were measured for all detected sources, using a method of slitless spectroscopy which we briefly describe. The radial velocities allow us to study the motions of different stellar populations in NGC 891. The PN kinematics show rotation at large distances from the galactic plane. Of particular interest is the strong asymmetry of PN distribution at large height, which we interpret as two possible stellar streams that could be orbiting the galaxy at large angles to the main structure. These streams, if real, are probably remnants of a previous minor merging episode. This idea finds support in recent reports of clump-like, incompletely mixed structures from deep HST/ACS images of this galaxy.

  13. Development of a kinematic 3D carpal model to analyze in vivo soft-tissue interaction across multiple static postures.

    PubMed

    Marai, G; Crisco, Joseph J; Laidlaw, David H

    2009-01-01

    We developed a subject-specific kinematic model to analyze in vivo soft-tissue interaction in the carpus in static, unloaded postures. The bone geometry was extracted from a reference computed tomography volume image. The soft-tissue geometry, including cartilage and ligament tissues, was computationally modeled based on kinematic constraints; the constraints were extracted from multiple computed tomography scans corresponding to different carpal postures. The data collected in vivo was next coupled with numerical simulation in order to analyze the role of soft-tissues in different postures. The resulting model extends the state of biomechanical modeling by incorporating soft-tissue constraints across the carpus range of motion, while successfully using only physiological constraints. The model results suggest that soft-tissue wrapping constraints have substantial impact on carpus stability.

  14. Singular Values of Products of Ginibre Random Matrices, Multiple Orthogonal Polynomials and Hard Edge Scaling Limits

    NASA Astrophysics Data System (ADS)

    Kuijlaars, Arno B. J.; Zhang, Lun

    2014-12-01

    Akemann, Ipsen and Kieburg recently showed that the squared singular values of products of M rectangular random matrices with independent complex Gaussian entries are distributed according to a determinantal point process with a correlation kernel that can be expressed in terms of Meijer G-functions. We show that this point process can be interpreted as a multiple orthogonal polynomial ensemble. We give integral representations for the relevant multiple orthogonal polynomials and a new double contour integral for the correlation kernel, which allows us to find its scaling limits at the origin (hard edge). The limiting kernels generalize the classical Bessel kernels. For M = 2 they coincide with the scaling limits found by Bertola, Gekhtman, and Szmigielski in the Cauchy-Laguerre two-matrix model, which indicates that these kernels represent a new universality class in random matrix theory.

  15. Exploring the alpha cluster structure of nuclei using the thick target inverse kinematics technique for multiple alpha decays

    NASA Astrophysics Data System (ADS)

    Barbui, M.; Hagel, K.; Goldberg, V. Z.; Natowitz, J. B.; Zheng, H.; Giuliani, G.; Rapisarda, G. G.; Wuenschel, S.; Liu, X.

    2014-03-01

    We explored alpha clustering in 24Mg using the reaction 20Ne+α and the Thick Target Inverse Kinematics (TTIK) technique. 20Ne beams of energy 3.7 AMeV and 11 AMeV were delivered by the K150 cyclotron at Texas A&M University. The reaction chamber was filled with 4He gas at a pressure sufficient to stop the beam before the detectors. The energy of the light reaction products was measured by three silicon detector telescopes. The time relative to the cyclotron radiofrequency was also measured. For the first time the TTIK method was used to study both single and multiple α-particle decays. New results were obtained on elastic resonant α scattering, as well as on inelastic processes leading to high excitation energy systems decaying by multiple α-particle emission. Preliminary results will be shown on events with α-multiplicity one and two.

  16. Influence of line-edge roughness on multiple-gate tunnel field-effect transistors

    NASA Astrophysics Data System (ADS)

    Choi, Woo Young

    2017-04-01

    The influence of fin-line-edge roughness (fin-LER) and gate-LER on multiple-gate (MG) tunnel field-effect transistors (TFETs) has been investigated compared with MG MOSFETs by using full three-dimensional technology computer-aided design (TCAD) simulation. From simulation results, two interesting results have been observed. First, MG TFETs show much less severe gate-LER than MG MOSFETs, which means that only fin-LER can be considered when evaluating the total LER of MG TFETs. Second, TFETs show ∼3× more LER improvement than MOSFETs when their structures are changed from double-gate (DG) to triple-gate (TG) ones. Our findings provide the useful design guidelines of variation-tolerant TFETs.

  17. Finite element analysis of head-neck kinematics during motor vehicle accidents: analysis in multiple planes.

    PubMed

    Teo, Ee Chon; Zhang, Qing Hang; Huang, Russel C

    2007-01-01

    In this study, a detailed three-dimensional head-neck (C0-C7) finite element (FE) model developed previously based on the actual geometry of a human cadaver specimen was used. Five simulation analyses were performed to investigate the kinematic responses of the head-neck complex under rear-end, front, side, rear- and front-side impacts. Under rear-end and front impacts, it was predicted that the global and intervertebral rotations of the head-neck in the sagittal plane displayed nearly symmetric curvatures about the frontal plane. The primary sagittal rotational angles of the neck under direct front and rear-end impact conditions were higher than the primary frontal rotational angles under other side impact conditions. The analysis predicted early S-shaped and subsequent C-shaped curvatures of the head-neck complex in the sagittal plane under front and rear-end impact, and in the frontal plane under side impact. The head-neck complex flexed laterally in one direction with peak magnitude of larger than 22 degrees and a duration of about 130 ms before flexing in the opposite direction under both side and rear-side impact, compared to the corresponding values of about 15 degrees and 105 ms under front-side impact. The C0-C7 FE model has reasonably predicted the effects of impact direction in the primary sagittal and frontal segmental motion and curvatures of the head-neck complex under various impact conditions.

  18. Multiple deformation at the western edge of the Carolina slate belt, north-central North Carolina

    SciTech Connect

    Hibbard, J.P.; Shell, G.S.; Wilkins, J.K. ); Samson, S.; Wortman, G. . Dept. of Geology)

    1994-03-01

    In north-central North Carolina, volcanic-plutonic rocks of the Carolina slate belt are separated from gneisses of the Milton belt to the west by a wide, ENE-trending, polygenetic structural zone. Within a portion of this zone, the Country Line Creek complex (CLCC) forms the western edge of the slate belt. Rocks of the CLCC span a wide age range and include mafic and granitoid gneisses with subordinate pelitic schist, granitoid pegmatite, and a concordant sheet-like intrusion, the Yanceyville metagranite. The complex is heterogeneously deformed and metamorphosed. Along the SE margin of the structural zone, steeply-dipping, strongly foliated biotite granitoid and mafic gneisses of the complex appear to be intruded by the Roxboro metagranite of the Carolina slate belt. To the NW, in more interior portions of the zone, the CLCC is affected by multiphase foliations and folds that record a dextral oblique normal shear event. Here, the Yanceyville metagranite is affected by a strong foliation that is folded. A preliminary new date on the Roxboro pluton of ca. 545 Ma, indicates a Late Precambrian or older timing of deformation along the SE margin of the zone. In contrast, a preliminary, ca. 340 Ma, age on the Yanceyville metagranite indicates multiple stage Late Paleozoic deformation for interior portions of the zone. Regional structural and isotopic data hint that the Precambrian deformation may record initial interactions between the Milton and Carolina slate belts. Subsequently, this contact was reactivated during Alleghanian orogenesis.

  19. Kinematic reduction of reaction-diffusion fronts with multiplicative noise: derivation of stochastic sharp-interface equations.

    PubMed

    Rocco, A; Ramírez-Piscina, L; Casademunt, J

    2002-05-01

    We study the dynamics of generic reaction-diffusion fronts, including pulses and chemical waves, in the presence of multiplicative noise. We discuss the connection between the reaction-diffusion Langevin-like field equations and the kinematic (eikonal) description in terms of a stochastic moving-boundary or sharp-interface approximation. We find that the effective noise is additive and we relate its strength to the noise parameters in the original field equations, to first order in noise strength, but including a partial resummation to all orders which captures the singular dependence on the microscopic cutoff associated with the spatial correlation of the noise. This dependence is essential for a quantitative and qualitative understanding of fluctuating fronts, affecting both scaling properties and nonuniversal quantities. Our results predict phenomena such as the shift of the transition point between the pushed and pulled regimes of front propagation, in terms of the noise parameters, and the corresponding transition to a non-Kardar-Parisi-Zhang universality class. We assess the quantitative validity of the results in several examples including equilibrium fluctuations and kinetic roughening. We also predict and observe a noise-induced pushed-pulled transition. The analytical predictions are successfully tested against rigorous results and show excellent agreement with numerical simulations of reaction-diffusion field equations with multiplicative noise.

  20. Exploring clustering in alpha-conjugate nuclei using the thick target inverse kinematic technique for multiple alpha emission

    NASA Astrophysics Data System (ADS)

    Barbui, M.; Hagel, K.; Gauthier, J.; Wuenschel, S.; Goldberg, V. Z.; Zheng, H.; Giuliani, G.; Rapisarda, G.; Kim, E.-J.; Liu, X.; Natowitz, J. B.; Desouza, R. T.; Hudan, S.; Fang, D.

    2015-10-01

    Searching for alpha cluster states analogous to the 12C Hoyle state in heavier alpha-conjugate nuclei can provide tests of the existence of alpha condensates in nuclear matter. Such states are predicted for 16O, 20Ne, 24Mg, etc. at excitation energies slightly above the decay threshold. The Thick Target Inverse Kinematics (TTIK) technique can be successfully used to study the breakup of excited self-conjugate nuclei into many alpha particles. The reaction 20Ne + α at 11 and 13 AMeV was studied at Cyclotron Institute at Texas A&M University. Here the TTIK method was used to study both single α-particle emission and multiple α-particle decays. Due to the limited statistics, only events with alpha multiplicity up to three were analyzed. The analysis of the three α-particle emission data allowed the identification of the Hoyle state and other 12C excited states decaying into three alpha particles. The results will be shown and compared with other data available in the literature. Another experiment is planned in August 2015 to study the system 28Si + α at 15 AMeV. Preliminary results will be shown. Supported by the U.S. DOE and the Robert A. Welch Foundation, Grant No. A0330.

  1. Continued Kinematic and Photometric Investigations of Hierarchical Solar-type Multiple Star Systems

    NASA Astrophysics Data System (ADS)

    Roberts, Lewis C., Jr.; Tokovinin, Andrei; Mason, Brian D.; Marinan, Anne D.

    2017-03-01

    We observed 15 of the solar-type binaries within 67 pc of the Sun previously observed by the Robo-AO system in the visible, with the PHARO near-infrared camera and the PALM-3000 adaptive optics system on the 5 m Hale telescope. The physical status of the binaries is confirmed through common proper motion and detection of orbital motion. In the process, we detected a new candidate companion to HIP 95309. We also resolved the primary of HIP 110626 into a close binary, making that system a triple. These detections increase the completeness of the multiplicity survey of the solar-type stars within 67 pc of the Sun. Combining our observations of HIP 103455 with archival astrometric measurements and RV measurements, we are able to compute the first orbit of HIP 103455, showing that the binary has a 68 year period. We place the components on a color–magnitude diagram and discuss each multiple system individually.

  2. Multiple-scattering calculations of the uranium {ital L}{sub 3}-edge x-ray-absorption near-edge structure

    SciTech Connect

    Hudson, E.A.; Rehr, J.J.; Bucher, J.J.

    1995-11-15

    A theoretical study of the uranium {ital L}{sub 3}-edge x-ray absorption near-edge structure (XANES) is presented for several uranium compounds, including oxides, intermetallics, uranyl fluoride, and {alpha}-uranium. Calculations were performed using FEFF6, an {ital ab} {ital initio} multiple-scattering (MS) code that includes the most important features of current theories. The results, which account for both the fine structure {chi} and the atomiclike background {mu}{sub 0} of the absorption coefficient {mu}, are compared to new and previously measured experimental spectra, reavealing very good agreement for most systems. For several compounds, a more detailed theoretical analysis determined the influence of cluster size and scattering order upon the calculated spectra. Results indicate that MS paths and scattering paths that include rather distant atoms make significant contributions for UO{sub 2}, whereas XANES for crystals with lower symmetry and density can be modeled using only shorter single-scattering paths. In most cases, assumption of a screened final state in the calculation gives better agreement with experiment than use of an unscreened final state. The successful modeling of spectra for a variety of different uranium compounds, with differing spectral features, indicates that the semirelativistic treatment of XANES used here is adequate even for heavy elements. The well-known resonance, observed experimentally for uranyl (UO{sub 2}{sup 2+}) compounds {approx}15 eV above the white line, is successfully modeled here for the first time, using multiple-scattering paths within the O-U-O axial bonds. Overlapping muffin-tin spheres were required in the calculation, probably as a result of the short uranyl axial bonds.

  3. Drift paths of ions composing multiple-nose spectral structures near the inner edge of the plasma sheet

    NASA Astrophysics Data System (ADS)

    Ferradas, C. P.; Zhang, J.-C.; Spence, H. E.; Kistler, L. M.; Larsen, B. A.; Reeves, G.; Skoug, R.; Funsten, H.

    2016-11-01

    We present a case study of the H+, He+, and O+ multiple-nose structures observed by the Helium, Oxygen, Proton, and Electron instrument on board Van Allen Probe A over one complete orbit on 28 September 2013. Nose structures are observed near the inner edge of the plasma sheet and constitute the signatures of ion drift in the highly dynamic environment of the inner magnetosphere. We find that the multiple noses are intrinsically associated with variations in the solar wind. Backward ion drift path tracings show new details of the drift trajectories of these ions; i.e., multiple noses are formed by ions with a short drift time from the assumed source location to the inner region and whose trajectories (1) encircle the Earth different number of times or (2) encircle the Earth equal number of times but with different drift time, before reaching the observation site.

  4. Multiple pre-edge structures in Cu K -edge x-ray absorption spectra of high- Tc cuprates revealed by high-resolution x-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Gougoussis, C.; Rueff, J.-P.; Calandra, M.; D'Astuto, M.; Jarrige, I.; Ishii, H.; Shukla, A.; Yamada, I.; Azuma, M.; Takano, M.

    2010-06-01

    Using high-resolution x-ray absorption spectroscopy and state-of-the-art electronic structure calculations we demonstrate that the pre-edge region at the Cu K edge of high- Tc cuprates is composed of several excitations invisible in standard x-ray absorption spectra. We consider in detail the case of Ca2-xCuO2Cl2 and show that the many pre-edge excitations (two for c -axis polarization, four for in-plane polarization and out-of-plane incident x-ray momentum) are dominated by off-site transitions and intersite hybridization. This demonstrates the relevance of approaches beyond the single-site model for the description of the pre edges of correlated materials. Finally, we show the occurrence of a doubling of the main edge peak that is most visible when the polarization is along the c axis. This doubling, that has not been seen in any previous absorption data in cuprates, is not reproduced by first-principles calculations. We suggest that this peak is due to many-body charge-transfer excitations while all the other visible far-edge structures are single particle in origin. Our work indicates that previous interpretations of the Cu K -edge x-ray absorption spectra in high- Tc cuprates can be profitably reconsidered.

  5. Unconfined, melt edge electrospinning from multiple, spontaneous, self-organized polymer jets

    NASA Astrophysics Data System (ADS)

    Wang, Qingqing; Curtis, Colin K.; Muthuraman Thoppey, Nagarajan; Bochinski, Jason R.; Gorga, Russell E.; Clarke, Laura I.

    2014-12-01

    Commercial grade polyethylene is melt electrospun from a thin film of unconfined molten polymer on a heated, electrically-grounded plate. Under the influence of an applied electric field, the melt spontaneously forms fingering perturbations at the plate edge which then evolve into emitting fiber-forming jets. Jet-to-jet spacing (˜5 mm), which is dependent on the applied voltage amplitude, is in agreement with estimates from a simple theoretical treatment. The broad applicability of the approach is verified by spinning a second polymer—polycaprolactone. In both cases, the fabricated fibers are similar in quality to those obtained under needle melt electrospinning; however for this method, there are no nozzles to clog and an enhanced production rate up to 80 mg min-1 is achieved from approximately 20-25 simultaneous parallel jets. The process of jet formation, effective flow rates, cone-jet diameters, as well as limits on jet density and differences with polymer type are compared with theoretical models. This particular approach allows facile, high throughput micro- and nano-fiber formation from a wide variety of thermoplastics and other high viscosity fluids without the use of solvents or the persistent issues of clogging and pumping that hamper traditional methods, resulting in mechanically strong meso-scale fibers highly desirable for industrial applications.

  6. Historical comparisons reveal multiple drivers of decadal change of an ecosystem engineer at the range edge.

    PubMed

    Firth, Louise B; Mieszkowska, Nova; Grant, Lisa M; Bush, Laura E; Davies, Andrew J; Frost, Matthew T; Moschella, Paula S; Burrows, Michael T; Cunningham, Paul N; Dye, Stephen R; Hawkins, Stephen J

    2015-08-01

    Biogenic reefs are important for habitat provision and coastal protection. Long-term datasets on the distribution and abundance of Sabellaria alveolata (L.) are available from Britain. The aim of this study was to combine historical records and contemporary data to (1) describe spatiotemporal variation in winter temperatures, (2) document short-term and long-term changes in the distribution and abundance of S. alveolata and discuss these changes in relation to extreme weather events and recent warming, and (3) assess the potential for artificial coastal defense structures to function as habitat for S. alveolata. A semi-quantitative abundance scale (ACFOR) was used to compare broadscale, long-term and interannual abundance of S. alveolata near its range edge in NW Britain. S. alveolata disappeared from the North Wales and Wirral coastlines where it had been abundant prior to the cold winter of 1962/1963. Population declines were also observed following the recent cold winters of 2009/2010 and 2010/2011. Extensive surveys in 2004 and 2012 revealed that S. alveolata had recolonized locations from which it had previously disappeared. Furthermore, it had increased in abundance at many locations, possibly in response to recent warming. S. alveolata was recorded on the majority of artificial coastal defense structures surveyed, suggesting that the proliferation of artificial coastal defense structures along this stretch of coastline may have enabled S. alveolata to spread across stretches of unsuitable natural habitat. Long-term and broadscale contextual monitoring is essential for monitoring responses of organisms to climate change. Historical data and gray literature can be invaluable sources of information. Our results support the theory that Lusitanian species are responding positively to climate warming but also that short-term extreme weather events can have potentially devastating widespread and lasting effects on organisms. Furthermore, the proliferation of

  7. THE HUBBLE SPACE TELESCOPE UV LEGACY SURVEY OF GALACTIC GLOBULAR CLUSTERS: THE INTERNAL KINEMATICS OF THE MULTIPLE STELLAR POPULATIONS IN NGC 2808

    SciTech Connect

    Bellini, A.; Anderson, J.; Marel, R. P. van der; Vesperini, E.; Hong, J.; Piotto, G.; Milone, A. P.; Marino, A. F.; Bedin, L. R.; Renzini, A.; Cassisi, S.; D’Antona, F.

    2015-09-01

    Numerous observational studies have revealed the ubiquitous presence of multiple stellar populations in globular clusters and cast many difficult challenges for the study of the formation and dynamical history of these stellar systems. In this Letter we present the results of a study of the kinematic properties of multiple populations in NGC 2808 based on high-precision Hubble Space Telescope proper-motion measurements. In a recent study, Milone et al. identified five distinct populations (A–E) in NGC 2808. Populations D and E coincide with the helium-enhanced populations in the middle and the blue main sequences (mMS and bMS) previously discovered by Piotto et al.; populations A–C correspond to the redder main sequence that, in Piotto et al., was associated with the primordial stellar population. Our analysis shows that, in the outermost regions probed (between about 1.5 and 2 times the cluster half-light radius), the velocity distribution of populations D and E is radially anisotropic (the deviation from an isotropic distribution is significant at the ∼3.5σ level). Stars of populations D and E have a smaller tangential velocity dispersion than those of populations A–C, while no significant differences are found in the radial velocity dispersion. We present the results of a numerical simulation showing that the observed differences between the kinematics of these stellar populations are consistent with the expected kinematic fingerprint of the diffusion toward the cluster outer regions of stellar populations initially more centrally concentrated.

  8. Historical comparisons reveal multiple drivers of decadal change of an ecosystem engineer at the range edge

    PubMed Central

    Firth, Louise B; Mieszkowska, Nova; Grant, Lisa M; Bush, Laura E; Davies, Andrew J; Frost, Matthew T; Moschella, Paula S; Burrows, Michael T; Cunningham, Paul N; Dye, Stephen R; Hawkins, Stephen J

    2015-01-01

    Biogenic reefs are important for habitat provision and coastal protection. Long-term datasets on the distribution and abundance of Sabellaria alveolata (L.) are available from Britain. The aim of this study was to combine historical records and contemporary data to (1) describe spatiotemporal variation in winter temperatures, (2) document short-term and long-term changes in the distribution and abundance of S. alveolata and discuss these changes in relation to extreme weather events and recent warming, and (3) assess the potential for artificial coastal defense structures to function as habitat for S. alveolata. A semi-quantitative abundance scale (ACFOR) was used to compare broadscale, long-term and interannual abundance of S. alveolata near its range edge in NW Britain. S. alveolata disappeared from the North Wales and Wirral coastlines where it had been abundant prior to the cold winter of 1962/1963. Population declines were also observed following the recent cold winters of 2009/2010 and 2010/2011. Extensive surveys in 2004 and 2012 revealed that S. alveolata had recolonized locations from which it had previously disappeared. Furthermore, it had increased in abundance at many locations, possibly in response to recent warming. S. alveolata was recorded on the majority of artificial coastal defense structures surveyed, suggesting that the proliferation of artificial coastal defense structures along this stretch of coastline may have enabled S. alveolata to spread across stretches of unsuitable natural habitat. Long-term and broadscale contextual monitoring is essential for monitoring responses of organisms to climate change. Historical data and gray literature can be invaluable sources of information. Our results support the theory that Lusitanian species are responding positively to climate warming but also that short-term extreme weather events can have potentially devastating widespread and lasting effects on organisms. Furthermore, the proliferation of

  9. Multi-long-slit Spectroscopy For Kinematic Studies. II. Initial Results For The Edge-on Galaxies NGC891 And NGC4244

    NASA Astrophysics Data System (ADS)

    Choi, Jiehae; Cisneros, S.; Wu, C.; Patterson, M.; Walterbos, R.

    2007-12-01

    We present results of observations of the edge-on galaxies NGC891 and NGC4244 using a multi-long-slit setup on the DIS spectrograph on the ARC 3.5m telescope. In combination with a 25A H-alpha filter, 16 slits of 2" by 4.5' could be observed simultaneously over a 4' by 4.5' field of view. The spectral resolution is 4 Anstrom. In the case of NGC891 we have obtained a deep spectrum of the Northern half of the halo, while for NGC4244 we obtained spectra with the slits oriented parallel to the major axis and a second exposure with the slits perpendicular to the major axis. In the case of NGC 891, the data were obtained to test the accuracy of our velocity measurements by comparison with previous observations, although we also do expand on the spatial coverage of ionized gas in the halo. For NGC4244, deep optical imaging has not shown a very extended diffuse ionized gas halo, and here our goal is to use the spectroscopic data to improve upon the limits set in the imaging studies. We present the results of these tests and discuss other implementations of the multi-long-slit setup. One of these is the possibility to perform deep spectroscopic searches for detection of ionized gas in galaxy halos through use of up to 45 slits when using a lower resolution grating. This research was supported by an award from Research Corporation.

  10. IONIZED GAS KINEMATICS AT HIGH RESOLUTION. V. [Ne ii], MULTIPLE CLUSTERS, HIGH EFFICIENCY STAR FORMATION, AND BLUE FLOWS IN HE 2–10

    SciTech Connect

    Beck, Sara; Turner, Jean; Lacy, John; Greathouse, Thomas

    2015-11-20

    We measured the 12.8 μm [Ne ii] line in the dwarf starburst galaxy He 2–10 with the high-resolution spectrometer TEXES on the NASA IRTF. The data cube has a diffraction-limited spatial resolution of ∼1″ and a total velocity resolution, including thermal broadening, of ∼5 km s{sup −1}. This makes it possible to compare the kinematics of individual star-forming clumps and molecular clouds in the three dimensions of space and velocity, and allows us to determine star formation efficiencies. The kinematics of the ionized gas confirm that the starburst contains multiple dense clusters. From the M/R of the clusters and the ≃30%–40% star formation efficiencies, the clusters are likely to be bound and long lived, like globulars. Non-gravitational features in the line profiles show how the ionized gas flows through the ambient molecular material, as well as a narrow velocity feature, which we identify with the interface of the H ii region and a cold dense clump. These data offer an unprecedented view of the interaction of embedded H ii regions with their environment.

  11. Use of L-edge X-ray absorption spectroscopy to characterize multiple valence states of 3 d transition metals; a new probe for mineralogical and geochemical research

    NASA Astrophysics Data System (ADS)

    Cressey, G.; Henderson, C. M. B.; van der Laan, G.

    1993-07-01

    2 p ( L 2,3) X-ray absorption spectra are presented for a range of minerals to demonstrate the usefulness of L-edge spectroscopy as a symmetry- and valenceselective probe. 2 p XAS provides a sensitive fingerprint of the electronic states of 3 d transition metals and can be applied to phases containing mixtures of such elements. Calculated spectra for 3 d n → 2 p 5 3 d n+1 transitions provide a basis for the interpretation of the measured spectra. Thus, in principle, multiple valence states of a particular 3 d metal can be precisely characterized from a single L-edge spectrum. Examples of vanadium L-edge spectra are presented for a range of minerals; these complex spectra hold information concerning the presence of vanadium in multiple valence states. The Cu L-edge spectrum of sulvanite (Cu3 VS4) indicates the presence of both Cu+ and Cu2+; the V L-edge spectrum of the same sample shows that both V2+ and V5+ are present. Spectral simulations representing mixtures of Fe d 5 and Fe d 6 states are used to quantify Fe3+/ ∑Fe in a spinel, a glass, and an amphibole, all of which contain Fe as a major component. To illustrate the sensitivity of 2 p XAS in a dilute system, the Fe L-edge spectrum of amethyst ( α-SiO2: Fe) has been recorded; this spectrum shows that ˜68% of the Fe in amethyst is Fe2+, and ˜32% is Fe3+. Although previous studies on amethyst using other spectroscopic methods cite evidence for Fe4+, there is no indication in the L-edge spectrum for Fe4+ in amethyst. Comparison of theoretical and experimental spectra not only allows the valence states of 3 d ions to be recognised, but also provides site-symmetry information and crystal field parameters for each ion site.

  12. Experimental evidence of transition between dynamical and kinematical diffraction regimes in ion-implanted Si observed through X-ray multiple-beam diffraction mappings

    NASA Astrophysics Data System (ADS)

    Calligaris, Guilherme A.; Lang, Rossano; Bettini, Jefferson; dos Santos, Adenilson O.; Cardoso, Lisandro P.

    2016-10-01

    In this paper, the dependence of a Laue diffraction streak on the crystalline perfection of Xe-implanted Si(001) substrates is presented, based on the observation in the X-ray multiple diffraction (XRMD) mappings, as an experimental evidence of the transition between dynamical and kinematical diffraction regimes. A direct observation of the implanted region by transmission electron microscopy revealed an amorphous Si layer, which recrystallizes into a heavily twinned and faulted microstructure after thermal treatment at 800 °C. Besides the lattice damages, the annealing induces the formation of Xe bubbles. Both singularly affect the XRMD pattern, primarily the four-fold streaks profile of the ( 000 ) ( 002 ) ( 1 1 ¯ 1 ¯ ) ( 1 1 ¯ 3 ) four-beam simultaneous case when compared with the pristine Si pattern, highlighting the intra- and inter-block diffractions and the role played by the primary extinction effect. Such features provide information on the dominant diffraction regime. The findings are also discussed and compared to the conventional reciprocal space mappings via the asymmetric Si(113) reflection.

  13. Robust design of multiple trailing edge flaps for helicopter vibration reduction: A multi-objective bat algorithm approach

    NASA Astrophysics Data System (ADS)

    Mallick, Rajnish; Ganguli, Ranjan; Seetharama Bhat, M.

    2015-09-01

    The objective of this study is to determine an optimal trailing edge flap configuration and flap location to achieve minimum hub vibration levels and flap actuation power simultaneously. An aeroelastic analysis of a soft in-plane four-bladed rotor is performed in conjunction with optimal control. A second-order polynomial response surface based on an orthogonal array (OA) with 3-level design describes both the objectives adequately. Two new orthogonal arrays called MGB2P-OA and MGB4P-OA are proposed to generate nonlinear response surfaces with all interaction terms for two and four parameters, respectively. A multi-objective bat algorithm (MOBA) approach is used to obtain the optimal design point for the mutually conflicting objectives. MOBA is a recently developed nature-inspired metaheuristic optimization algorithm that is based on the echolocation behaviour of bats. It is found that MOBA inspired Pareto optimal trailing edge flap design reduces vibration levels by 73% and flap actuation power by 27% in comparison with the baseline design.

  14. Edge-based lightweight image encryption using chaos-based reversible hidden transform and multiple-order discrete fractional cosine transform

    NASA Astrophysics Data System (ADS)

    Zhang, Yushu; Xiao, Di; Wen, Wenying; Tian, Yuan

    2013-12-01

    In some special multimedia applications, only the regions with semantic information should be provided better protection whereas the other smooth regions can be free of encryption. However, most of the existing multimedia security schemes only consider bits and pixels rather than semantic information during their encryption. Motivated by this, we propose an edge-based lightweight image encryption scheme using chaos-based reversible hidden transform and multiple-order discrete fractional cosine transform. An image is first carried out by the edge detection based on advanced CNN structure with adaptive thresholds to assess data significance in the image. The detection output is a binary image, in which a “1” reflects the detected pixel whereas a “0” is opposite. Both the detected image and the original image are divided into non-overlapping pixel blocks in the same way, respectively. Whether each block is encrypted or not depends on the significance judged by the corresponding detected block. The significant block is performed by reversible hidden transform followed by multiple-order discrete fractional cosine transform parameters and orders of these two transforms are determined by a two dimensional cross chaotic map. Experiment results show the significant contour features of an image that have been largely hidden only by encrypting about half pixels in the average sense. The keys are extremely sensitive and the proposed scheme can resist noise attack to some extent.

  15. An application of the edge effect in measuring accessibility to multiple food retailer types in Southwestern Ontario, Canada

    PubMed Central

    2011-01-01

    Background Trends in food retailing associated with the consolidation of smaller-format retailers into fewer, larger-format supercentres have left some rural areas with fewer sources of nutritious, affordable food. Access to nutritious, affordable food is essential for good dietary habits and combating health issues such as type-2 diabetes, obesity, and cardiovascular disease. Many studies on food environments use inaccurate or incomplete methods for locating food retailers, which may be responsible for mischaracterising food deserts. This study uses databases of every residence in and every food retailer in and around Middlesex County, Ontario, Canada. Residences were geocoded to their precise address, and network analysis techniques were performed in a geographic information system (GIS) to determine distances between every residence and different types of food retailers (grocery stores, fast food, fruit and vegetable sources, grocery stores plus fruit and vegetable sources, variety stores), both when considering and neglecting facilities outside the area of study, to account for a deficiency in analysis termed the 'edge effect'. Results Analysis of household accessibility to food outlets by neighbourhood socioeconomic distress level indicated that residents in the most distressed neighbourhoods tended to have better accessibility to all types of food retailers. In the most distressed neighbourhoods, 79 percent of residences were within walking distance of a grocery store, compared to only 10 percent in the least distressed neighbourhoods. When the edge effect was neglected, 37 percent of distance estimates proved inaccurate. Average accessibility to all food retailer types improved dramatically when food outlets adjacent to the study area were considered, thereby controlling for the edge effect. Conclusion By neglecting to consider food retailers just outside study area boundaries, previous studies may significantly over-report the actual distance necessary to

  16. Ni K-Edge XANES Analyses of Residual Ni Catalyst in Carbon Nanofiber Using Full Multiple Scattering Theory

    SciTech Connect

    Ushiro, Mayuko; Ohminami, Kenryo; Nagamatsu, Shin-ichi; Fujikawa, Takashi; Asakura, Kiyotaka

    2007-02-02

    Residual Ni species after Ni removal treatment of carbon nanofibers have been investigated by use of XAFS analyses. Most of the Ni impurities are in Ni monomer which is located on defects in carbon nanofibers. The XAFS analyses combined with the multiple scattering theory give useful information on nano-structures of small amount species. Molecular orbital calculation also support the results from the XAFS analyses.

  17. Multiple mobility edges in a 1D Aubry chain with Hubbard interaction in presence of electric field: Controlled electron transport

    NASA Astrophysics Data System (ADS)

    Saha, Srilekha; Maiti, Santanu K.; Karmakar, S. N.

    2016-09-01

    Electronic behavior of a 1D Aubry chain with Hubbard interaction is critically analyzed in presence of electric field. Multiple energy bands are generated as a result of Hubbard correlation and Aubry potential, and, within these bands localized states are developed under the application of electric field. Within a tight-binding framework we compute electronic transmission probability and average density of states using Green's function approach where the interaction parameter is treated under Hartree-Fock mean field scheme. From our analysis we find that selective transmission can be obtained by tuning injecting electron energy, and thus, the present model can be utilized as a controlled switching device.

  18. Kinematic space and wormholes

    NASA Astrophysics Data System (ADS)

    Zhang, Jian-dong; Chen, Bin

    2017-01-01

    The kinematic space could play a key role in constructing the bulk geometry from dual CFT. In this paper, we study the kinematic space from geometric points of view, without resorting to differential entropy. We find that the kinematic space could be intrinsically defined in the embedding space. For each oriented geodesic in the Poincaré disk, there is a corresponding point in the kinematic space. This point is the tip of the causal diamond of the disk whose intersection with the Poincaré disk determines the geodesic. In this geometric construction, the causal structure in the kinematic space can be seen clearly. Moreover, we find that every transformation in the SL(2,R) leads to a geodesic in the kinematic space. In particular, for a hyperbolic transformation defining a BTZ black hole, it is a timelike geodesic in the kinematic space. We show that the horizon length of the static BTZ black hole could be computed by the geodesic length of corresponding points in the kinematic space. Furthermore, we discuss the fundamental regions in the kinematic space for the BTZ blackhole and multi-boundary wormholes.

  19. Edge remap for solids

    SciTech Connect

    Kamm, James R.; Love, Edward; Robinson, Allen C.; Young, Joseph G.; Ridzal, Denis

    2013-12-01

    We review the edge element formulation for describing the kinematics of hyperelastic solids. This approach is used to frame the problem of remapping the inverse deformation gradient for Arbitrary Lagrangian-Eulerian (ALE) simulations of solid dynamics. For hyperelastic materials, the stress state is completely determined by the deformation gradient, so remapping this quantity effectively updates the stress state of the material. A method, inspired by the constrained transport remap in electromagnetics, is reviewed, according to which the zero-curl constraint on the inverse deformation gradient is implicitly satisfied. Open issues related to the accuracy of this approach are identified. An optimization-based approach is implemented to enforce positivity of the determinant of the deformation gradient. The efficacy of this approach is illustrated with numerical examples.

  20. Edge Bioinformatics

    SciTech Connect

    Lo, Chien-Chi

    2015-08-03

    Edge Bioinformatics is a developmental bioinformatics and data management platform which seeks to supply laboratories with bioinformatics pipelines for analyzing data associated with common samples case goals. Edge Bioinformatics enables sequencing as a solution and forward-deployed situations where human-resources, space, bandwidth, and time are limited. The Edge bioinformatics pipeline was designed based on following USE CASES and specific to illumina sequencing reads. 1. Assay performance adjudication (PCR): Analysis of an existing PCR assay in a genomic context, and automated design of a new assay to resolve conflicting results; 2. Clinical presentation with extreme symptoms: Characterization of a known pathogen or co-infection with a. Novel emerging disease outbreak or b. Environmental surveillance

  1. The kinematic footprints of five stellar streams in Andromeda's halo

    NASA Astrophysics Data System (ADS)

    Chapman, S. C.; Ibata, R.; Irwin, M.; Koch, A.; Letarte, B.; Martin, N.; Collins, M.; Lewis, G. F.; McConnachie, A.; Peñarrubia, J.; Rich, R. M.; Trethewey, D.; Ferguson, A.; Huxor, A.; Tanvir, N.

    2008-11-01

    We present a spectroscopic analysis of five stellar streams (`A', `B', `Cr', `Cp' and `D') as well as the extended star cluster, EC4, which lies within Stream`C', all discovered in the halo of M31 from our Canada-France-Hawaii Telescope/MegaCam survey. These spectroscopic results were initially serendipitous, making use of our existing observations from the DEep Imaging Multi-Object Spectrograph mounted on the Keck II telescope, and thereby emphasizing the ubiquity of tidal streams that account for ~70 per cent of the M31 halo stars in the targeted fields. Subsequent spectroscopy was then procured in Stream`C' and Stream`D' to trace the velocity gradient along the streams. Nine metal-rich ([Fe/H] ~ -0.7) stars at vhel = -349.5kms-1,σv,corr ~ 5.1 +/- 2.5km s-1 are proposed as a serendipitous detection of Stream`Cr', with follow-up kinematic identification at a further point along the stream. Seven metal-poor ([Fe/H] ~-1.3) stars confined to a narrow, 15 km s-1 velocity bin centred at vhel = -285.6, σv,corr = 4.3+1.7-1.4 km s-1 represent a kinematic detection of Stream`Cp', again with follow-up kinematic identification further along the stream. For the cluster EC4, candidate member stars with average [Fe/H] ~-1.4, are found at vhel = -282 suggesting it could be related to Stream`Cp'. No similarly obvious cold kinematic candidate is found for Stream`D', although candidates are proposed in both of two spectroscopic pointings along the stream (both at ~ -400km s-1). Spectroscopy near the edge of Stream`B' suggests a likely kinematic detection at vhel ~ -330, σv,corr ~ 6.9km s-1, while a candidate kinematic detection of Stream`A' is found (plausibly associated to M33 rather than M31) with vhel ~ -170, σv,corr = 12.5km s-1. The low dispersion of the streams in kinematics, physical thickness and metallicity makes it hard to reconcile with a scenario whereby these stream structures as an ensemble are related to the giant southern stream. We conclude that the M31 stellar

  2. Full multiple scattering analysis of XANES at the Cd L3 and O K edges in CdO films combined with a soft-x-ray emission investigation

    SciTech Connect

    Demchenko, I. N.; Denlinger, J. D.; Chernyshova, M.; Yu, K. M.; Speaks, D. T.; Olalde-Velasco, P.; Hemmers, O.; Walukiewicz, W.; Derkachova, A.; Lawniczak-Jablonska, K.

    2010-07-05

    X-ray absorption near edge structure (XANES) at the cadmium L3 and oxygen K edges for CdO thin films grown by pulsed laser deposition method, is interpreted within the real-space multiple scattering formalism, FEFF code. The features in the experimental spectra are well reproduced by calculations for a cluster of about six and ten coordination shells around the absorber for L3 edge of Cd and K edge of O, respectively. The calculated projected electronic density of states is found to be in good agreement with unoccupied electronic states in experimental data and allows to conclude that the orbital character of the lowest energy of the conductive band is Cd-5s-O-2p. The charge transfer has been quantified and not purely ionic bonding has been found. Combined XANES and resonant inelastic x-ray scattering measurements allow us to determine the direct and indirect band gap of investigated CdO films to be {approx}2.4-eV and {approx}0.9-eV, respectively.

  3. A Novel Algorithm for the Generation of Distinct Kinematic Chain

    NASA Astrophysics Data System (ADS)

    Medapati, Sreenivasa Reddy; Kuchibhotla, Mallikarjuna Rao; Annambhotla, Balaji Srinivasa Rao

    2016-07-01

    Generation of distinct kinematic chains is an important topic in the design of mechanisms for various industrial applications i.e., robotic manipulator, tractor, crane etc. Many researchers have intently focused on this area and explained various processes of generating distinct kinematic chains which are laborious and complex. It is desirable to enumerate the kinematic chains systematically to know the inherent characteristics of a chain related to its structure so that all the distinct chains can be analyzed in depth, prior to the selection of a chain for a purpose. This paper proposes a novel and simple method with set of rules defined to eliminate isomorphic kinematic chains generating distinct kinematic chains. Also, this method simplifies the process of generating distinct kinematic chains even at higher levels i.e., 10-link, 11-link with single and multiple degree of freedom.

  4. Studies on the Structural Transformation of Pt Clusters with Adsorbed Hydrogen on α-Al2O3(0001) Using Multiple Scattering Approach to Pt L3-edge Polarized X-Ray Absorption Near Edge Structure Spectra for the Pt Cluster

    NASA Astrophysics Data System (ADS)

    Ohtani, Kunihiro

    1998-03-01

    The X-ray absorption near edge structure (XANES) or the Extended X-ray absorption fine structure (EXAFS) study with polarization dependence is useful for determining the structures of the metal clusters. We have calculated Pt L3-edge XANES spectra for various structures of Pt clusters with adsorbed hydrogen, such as the one-layer-thick raft, and the hemispherical and spherical structures on α-Al2O3(0001), using the full multiple scattering approach. Comparison of the calculated results with the experimental results have yielded important information. With an increase in the spherically symmetric character of Pt clusters, the influence of Pt-support interaction on the XANES spectra decreases, that is, the hydrogen-Pt interaction plays a dominant role in such cases. We expect that Pt clusters with the one-layer-thick raft, or hemispherical structures are on the top site of surface oxygen atoms.

  5. Edge Detection,

    DTIC Science & Technology

    1985-09-01

    PROJECT. T ASK0 Artificial Inteligence Laboratory AREA It WORK UNIT NUMBERS V 545 Technology Square ( Cambridge, HA 02139 I I* CONTOOL1LIN@4OFFICE NAME...ARD-A1t62 62 EDGE DETECTION(U) NASSACNUSETTS INST OF TECH CAMBRIDGE 1/1 ARTIFICIAL INTELLIGENCE LAB E C HILDRETH SEP 85 AI-M-8 N99SI4-8S-C-6595...used to carry out this analysis. cce~iO a N) ’.~" D LI’BL. P p ------------ Sj. t i MASSACHUSETTS INSTITUTE OF TECHNOLOGY i ARTIFICIAL INTELLIGENCE

  6. Inverse Kinematics of Concentric Tube Steerable Needles

    PubMed Central

    Sears, Patrick; Dupont, Pierre E.

    2013-01-01

    Prior papers have introduced steerable needles composed of precurved concentric tubes. The curvature and extent of these needles can be controlled by the relative rotation and translation of the individual tubes. Under certain assumptions on the geometry and design of these needles, the forward kinematics problem can be solved in closed form by means of algebraic equations. The inverse kinematics problem, however, is not as straightforward owing to the nonlinear map between relative tube displacements and needle tip configuration as well as to the multiplicity of solutions as the number of tubes increases. This paper presents a general approach to solving the inverse kinematics problem using a pseudoinverse solution together with gradients of nullspace potential functions to enforce geometric and mechanical constraints. PMID:23685532

  7. The brown dwarf kinematics project

    NASA Astrophysics Data System (ADS)

    Faherty, Jackie K.

    2010-10-01

    Brown dwarfs are a recent addition to the plethora of objects studied in Astronomy. With theoretical masses between 13 and 75 MJupiter , they lack sustained stable Hydrogen burning so they never join the stellar main sequence. They have physical properties similar to both planets and low-mass stars so studies of their population inform on both. The distances and kinematics of brown dwarfs provide key statistical constraints on their ages, moving group membership, absolute brightnesses, evolutionary trends, and multiplicity. Yet, until my thesis, fundamental measurements of parallax and proper motion were made for only a relatively small fraction of the known population. To address this deficiency, I initiated the Brown Dwarf Kinematics (BDKP). Over the past four years I have re-imaged the majority of spectroscopically confirmed field brown dwarfs (or ultracool dwarfs---UCDs) and created the largest proper motion catalog for ultracool dwarfs to date. Using new astrometric information I examined population characteristics such as ages calculated from velocity dispersions and correlations between kinematics and colors. Using proper motions, I identified several new wide co-moving companions and investigated binding energy (and hence formation) limitations as well as the frequency of hierarchical companions. Concurrently over the past four years I have been conducting a parallax survey of 84 UCDs including those showing spectral signatures of youth, metal-poor brown dwarfs, and those within 20 pc of the Sun. Using absolute magnitude relations in J,H, and K, I identified overluminous binary candidates and investigated known flux-reversal binaries. Using current evolutionary models, I compared the MK vs J-K color magnitude diagram to model predictions and found that the low-surface gravity dwarfs are significantly red-ward and underluminous of predictions and a handful of late-type T dwarfs may require thicker clouds to account for their scatter.

  8. Dislocation kinematics: a molecular dynamics study in Cu

    NASA Astrophysics Data System (ADS)

    Oren, E.; Yahel, E.; Makov, G.

    2017-02-01

    The kinematics and kinetics of edge and screw dislocations in FCC materials were studied by molecular dynamics, with Cu as a case study. It was found that with increasing stress screw dislocations enter into the transonic regime continuously and that they remain stable up to a velocity of about 2.2 km s-1. Edge dislocations are limited by the transverse sound velocity at low stresses and discontinuously cross into the transonic regime at higher stresses. For sufficiently long edge dislocations, the subsonic-transonic transition is initiated by an athermal nucleation process. Finally, an expression for the velocity dependence of the dislocation mobility was derived.

  9. Three tooth kinematic coupling

    DOEpatents

    Hale, Layton C.

    2000-01-01

    A three tooth kinematic coupling based on having three theoretical line contacts formed by mating teeth rather than six theoretical point contacts. The geometry requires one coupling half to have curved teeth and the other coupling half to have flat teeth. Each coupling half has a relieved center portion which does not effect the kinematics, but in the limit as the face width approaches zero, three line contacts become six point contacts. As a result of having line contact, a three tooth coupling has greater load capacity and stiffness. The kinematic coupling has application for use in precision fixturing for tools or workpieces, and as a registration device for a work or tool changer or for optics in various products.

  10. The effect of multiple fixed slots and a trailing-edge flap on the lift and drag of a Clark Y airfoil

    NASA Technical Reports Server (NTRS)

    Weick, Fred E; Shortal, Joseph A

    1933-01-01

    Lift and drag tests were made on a Clark Y wing equipped with four fixed slots and a trailing-edge flap in the 5-foot vertical wind tunnel of the National Advisory Committee for Aeronautics. All possible combinations of the four slots were tested with the flap neutral and the most promising combinations were tested with the flap down 45 degrees. Considering both the maximum lift coefficient and the speed-range ratio with the flap neutral no appreciable improvement was found with the use of more than the single leading-edge slot. With the flap down 45 degrees a maximum lift coefficient of 2.60 was obtained but the particular slot combination used had a rather large minimum drag coefficient with the flap neutral. With the flap down 45 degrees the optimum combination, considering both the maximum lift coefficient and the speed-range ratio, was obtained with only the two rearmost slots in use. For this arrangement the maximum lift coefficient was 2.44.

  11. The Edge

    NASA Technical Reports Server (NTRS)

    2006-01-01

    6 April 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the edge (running diagonally from the lower left to the upper right) of a trough, which is part of a large pit crater complex in Noachis Terra. This type of trough forms through the collapse of surface materials into the subsurface, and often begins as a series of individual pit craters. Over time, continued collapse increases the diameter of individual pits until finally, adjacent pits merge to form a trough such as the one captured in this image. The deep shadowed area is caused in part by an overhang; layered rock beneath this overhang is less resistant to erosion, and thus has retreated tens of meters backward, beneath the overhang. A person could walk up inside this 'cave' formed by the overhanging layered material.

    Location near: 47.0oS, 355.7oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  12. Kinematics and wing shape across flight speed in the bat, Leptonycteris yerbabuenae.

    PubMed

    Von Busse, Rhea; Hedenström, Anders; Winter, York; Johansson, L Christoffer

    2012-12-15

    The morphology and kinematics of a flying animal determines the resulting aerodynamic lift through the regulation of the speed of the air moving across the wing, the wing area and the lift coefficient. We studied the detailed three-dimensional wingbeat kinematics of the bat, Leptonycteris yerbabuenae, flying in a wind tunnel over a range of flight speeds (0-7 m/s), to determine how factors affecting the lift production vary across flight speed and within wingbeats. We found that the wing area, the angle of attack and the camber, which are determinants of the lift production, decreased with increasing speed. The camber is controlled by multiple mechanisms along the span, including the deflection of the leg relative to the body, the bending of the fifth digit, the deflection of the leading edge flap and the upward bending of the wing tip. All these measures vary throughout the wing beat suggesting active or aeroelastic control. The downstroke Strouhal number, St(d), is kept relatively constant, suggesting that favorable flow characteristics are maintained during the downstroke, across the range of speeds studied. The St(d) is kept constant through changes in the stroke plane, from a strongly inclined stroke plane at low speeds to a more vertical stroke plane at high speeds. The mean angular velocity of the wing correlates with the aerodynamic performance and shows a minimum at the speed of maximum lift to drag ratio, suggesting a simple way to determine the optimal speed from kinematics alone. Taken together our results show the high degree of adjustments that the bats employ to fine tune the aerodynamics of the wings and the correlation between kinematics and aerodynamic performance.

  13. Teaching about Kinematics

    ERIC Educational Resources Information Center

    Nelson, Jane Bray; Nelson, Jim

    2009-01-01

    Written by Jim and Jane Nelson, Teaching About Kinematics is the latest AAPT/PTRA resource book. Based on physics education research, the book provides teachers with the resources needed to introduce students to some of the fundamental building blocks of physics. It is a carefully thought-out, step-by-step laboratory-based introduction to the…

  14. Kinematically redundant robot manipulators

    NASA Technical Reports Server (NTRS)

    Baillieul, J.; Hollerbach, J.; Brockett, R.; Martin, D.; Percy, R.; Thomas, R.

    1987-01-01

    Research on control, design and programming of kinematically redundant robot manipulators (KRRM) is discussed. These are devices in which there are more joint space degrees of freedom than are required to achieve every position and orientation of the end-effector necessary for a given task in a given workspace. The technological developments described here deal with: kinematic programming techniques for automatically generating joint-space trajectories to execute prescribed tasks; control of redundant manipulators to optimize dynamic criteria (e.g., applications of forces and moments at the end-effector that optimally distribute the loading of actuators); and design of KRRMs to optimize functionality in congested work environments or to achieve other goals unattainable with non-redundant manipulators. Kinematic programming techniques are discussed, which show that some pseudo-inverse techniques that have been proposed for redundant manipulator control fail to achieve the goals of avoiding kinematic singularities and also generating closed joint-space paths corresponding to close paths of the end effector in the workspace. The extended Jacobian is proposed as an alternative to pseudo-inverse techniques.

  15. Kinematics of Tape Recording.

    ERIC Educational Resources Information Center

    Coleman, J. J.

    1982-01-01

    Describes mathematics of the nonliner relationships between a constant-speed, capstan-driven magnetic tape transport mechanism and a constant-angular-velocity take-up reel. The relationship, derived from the sum of a partial, serves in recognition of a finite tape. Thickness can serve as an example of rotational kinematics. (Author/SK)

  16. Inverse Kinematic Analysis of Human Hand Thumb Model

    NASA Astrophysics Data System (ADS)

    Toth-Tascau, Mirela; Pater, Flavius; Stoia, Dan Ioan; Menyhardt, Karoly; Rosu, Serban; Rusu, Lucian; Vigaru, Cosmina

    2011-09-01

    This paper deals with a kinematic model of the thumb of the human hand. The proposed model has 3 degrees of freedom being able to model the movements of the thumb tip with respect to the wrist joint centre. The kinematic equations are derived based on Denavit-Hartenberg Convention and solved in both direct and inverse way. Inverse kinematic analysis of human hand thumb model reveals multiple and connected solutions which are characteristic to nonlinear systems when the number of equations is greater than number of unknowns and correspond to natural movements of the finger.

  17. The Photometric and Kinematic Structure of Face-on Disk Galaxies. III. Kinematic Inclinations from Hα Velocity Fields

    NASA Astrophysics Data System (ADS)

    Andersen, David R.; Bershady, Matthew A.

    2013-05-01

    Using the integral field unit DensePak on the WIYN 3.5 m telescope we have obtained Hα velocity fields of 39 nearly face-on disks at echelle resolutions. High-quality, uniform kinematic data and a new modeling technique enabled us to derive accurate and precise kinematic inclinations with mean i kin = 23° for 90% of these galaxies. Modeling the kinematic data as single, inclined disks in circular rotation improves upon the traditional tilted-ring method. We measure kinematic inclinations with a precision in sin i of 25% at 20° and 6% at 30°. Kinematic inclinations are consistent with photometric and inverse Tully-Fisher inclinations when the sample is culled of galaxies with kinematic asymmetries, for which we give two specific prescriptions. Kinematic inclinations can therefore be used in statistical "face-on" Tully-Fisher studies. A weighted combination of multiple, independent inclination measurements yield the most precise and accurate inclination. Combining inverse Tully-Fisher inclinations with kinematic inclinations yields joint probability inclinations with a precision in sin i of 10% at 15° and 5% at 30°. This level of precision makes accurate mass decompositions of galaxies possible even at low inclination. We find scaling relations between rotation speed and disk-scale length identical to results from more inclined samples. We also observe the trend of more steeply rising rotation curves with increased rotation speed and light concentration. This trend appears to be uncorrelated with disk surface brightness.

  18. Edge location to subpixel values in digital imagery.

    PubMed

    Tabatabai, A J; Mitchell, O R

    1984-02-01

    A new method for locating edges in digital data to subpixel values and which is invariant to additive and multiplicative changes in the data is presented. For one-dimensional edge patterns an ideal edge is fit to the data by matching moments. It is shown that the edge location is related to the so-called ``Christoffel numbers.'' Also presented is the study of the effect of additive noise on edge location. The method is extended to include two-dimensional edge patterns where a line equation is derived to locate an edge. This in turn is compared with the standard Hueckel edge operator. An application of the new edge operator as an edge detector is also provided and is compared with Sobel and Hueckel edge detectors in presence and absence of noise.

  19. APOGEE Kinematics. I. Overview of the Kinematics of the Galactic Bulge as Mapped By APOGEE

    NASA Astrophysics Data System (ADS)

    Ness, M.; Zasowski, G.; Johnson, J. A.; Athanassoula, E.; Majewski, S. R.; García Pérez, A. E.; Bird, J.; Nidever, D.; Schneider, Donald P.; Sobeck, J.; Frinchaboy, P.; Pan, Kaike; Bizyaev, Dmitry; Oravetz, Daniel; Simmons, Audrey

    2016-03-01

    We present the stellar kinematics across the Galactic bulge and into the disk at positive longitudes from the SDSS-III APOGEE spectroscopic survey of the Milky Way. APOGEE includes extensive coverage of the stellar populations of the bulge along the midplane and near-plane regions. From these data, we have produced kinematic maps of 10,000 stars across longitudes of 0° < l < 65°, and primarily across latitudes of | b| < 5° in the bulge region. The APOGEE data reveal that the bulge is cylindrically rotating across all latitudes and is kinematically hottest at the very center of the bulge, with the smallest gradients in both kinematic and chemical space inside the innermost region (| l,b| ) < (5°, 5°). The results from APOGEE show good agreement with data from other surveys at higher latitudes and a remarkable similarity to the rotation and dispersion maps of barred galaxies viewed edge-on. The thin bar that is reported to be present in the inner disk within a narrow latitude range of | b| < 2° appears to have a corresponding signature in [{Fe}/{{H}}] and [α /{Fe}]. Stars with [{Fe}/{{H}}] > -0.5 have dispersion and rotation profiles that are similar to that of N-body models of boxy/peanut bulges. There is a smooth kinematic transition from the thin bar and boxy bulge (l,| b| ) < (15°, 12°) out to the disk for stars with [{Fe}/{{H}}] > -1.0, and the chemodynamics across (l, b) suggests that the stars in the inner Galaxy with [{Fe}/{{H}}] > -1.0 originate in the disk.

  20. Kinematic Downsizing at z ˜ 2

    NASA Astrophysics Data System (ADS)

    Simons, Raymond C.; Kassin, Susan A.; Trump, Jonathan R.; Weiner, Benjamin J.; Heckman, Timothy M.; Barro, Guillermo; Koo, David C.; Guo, Yicheng; Pacifici, Camilla; Koekemoer, Anton; Stephens, Andrew W.

    2016-10-01

    We present results from a survey of the internal kinematics of 49 star-forming galaxies at z˜ 2 in the CANDELS fields with the Keck/MOSFIRE spectrograph, Survey in the near-Infrared of Galaxies with Multiple position Angles (SIGMA). Kinematics (rotation velocity V rot and gas velocity dispersion {σ }g) are measured from nebular emission lines which trace the hot ionized gas surrounding star-forming regions. We find that by z˜ 2, massive star-forming galaxies ({log} {M}* /{M}⊙ ≳ 10.2) have assembled primitive disks: their kinematics are dominated by rotation, they are consistent with a marginally stable disk model, and they form a Tully-Fisher relation. These massive galaxies have values of {V}{rot}/{σ }g that are factors of 2-5 lower than local well-ordered galaxies at similar masses. Such results are consistent with findings by other studies. We find that low-mass galaxies ({log} {M}* /{M}⊙ ≲ 10.2) at this epoch are still in the early stages of disk assembly: their kinematics are often dominated by gas velocity dispersion and they fall from the Tully-Fisher relation to significantly low values of V rot. This “kinematic downsizing” implies that the process(es) responsible for disrupting disks at z˜ 2 have a stronger effect and/or are more active in low-mass systems. In conclusion, we find that the period of rapid stellar mass growth at z˜ 2 is coincident with the nascent assembly of low-mass disks and the assembly and settling of high-mass disks.

  1. Real-time edge tracking using a tactile sensor

    NASA Technical Reports Server (NTRS)

    Berger, Alan D.; Volpe, Richard; Khosla, Pradeep K.

    1989-01-01

    Object recognition through the use of input from multiple sensors is an important aspect of an autonomous manipulation system. In tactile object recognition, it is necessary to determine the location and orientation of object edges and surfaces. A controller is proposed that utilizes a tactile sensor in the feedback loop of a manipulator to track along edges. In the control system, the data from the tactile sensor is first processed to find edges. The parameters of these edges are then used to generate a control signal to a hybrid controller. Theory is presented for tactile edge detection and an edge tracking controller. In addition, experimental verification of the edge tracking controller is presented.

  2. Predicting Human Protein Subcellular Locations by the Ensemble of Multiple Predictors via Protein-Protein Interaction Network with Edge Clustering Coefficients

    PubMed Central

    Du, Pufeng; Wang, Lusheng

    2014-01-01

    One of the fundamental tasks in biology is to identify the functions of all proteins to reveal the primary machinery of a cell. Knowledge of the subcellular locations of proteins will provide key hints to reveal their functions and to understand the intricate pathways that regulate biological processes at the cellular level. Protein subcellular location prediction has been extensively studied in the past two decades. A lot of methods have been developed based on protein primary sequences as well as protein-protein interaction network. In this paper, we propose to use the protein-protein interaction network as an infrastructure to integrate existing sequence based predictors. When predicting the subcellular locations of a given protein, not only the protein itself, but also all its interacting partners were considered. Unlike existing methods, our method requires neither the comprehensive knowledge of the protein-protein interaction network nor the experimentally annotated subcellular locations of most proteins in the protein-protein interaction network. Besides, our method can be used as a framework to integrate multiple predictors. Our method achieved 56% on human proteome in absolute-true rate, which is higher than the state-of-the-art methods. PMID:24466278

  3. Decoding intentions from movement kinematics

    PubMed Central

    Cavallo, Andrea; Koul, Atesh; Ansuini, Caterina; Capozzi, Francesca; Becchio, Cristina

    2016-01-01

    How do we understand the intentions of other people? There has been a longstanding controversy over whether it is possible to understand others’ intentions by simply observing their movements. Here, we show that indeed movement kinematics can form the basis for intention detection. By combining kinematics and psychophysical methods with classification and regression tree (CART) modeling, we found that observers utilized a subset of discriminant kinematic features over the total kinematic pattern in order to detect intention from observation of simple motor acts. Intention discriminability covaried with movement kinematics on a trial-by-trial basis, and was directly related to the expression of discriminative features in the observed movements. These findings demonstrate a definable and measurable relationship between the specific features of observed movements and the ability to discriminate intention, providing quantitative evidence of the significance of movement kinematics for anticipating others’ intentional actions. PMID:27845434

  4. Edge detecting new physics the Voronoi way

    NASA Astrophysics Data System (ADS)

    Debnath, Dipsikha; Gainer, James S.; Kim, Doojin; Matchev, Konstantin T.

    2016-05-01

    Edge detection is an important tool in the search for and exploration of physics beyond the standard model. Ideally one would be able to perform edge detection in a relatively model-independent way, however most analyses rely on more detailed properties (i.e. “shapes” or likelihood distributions) of the variable(s) of interest. We therefore present a sketch of how edge detection can be accomplished using Voronoi tessellations, focusing on the case of two-dimensional distributions for simplicity. After deriving some useful properties of the Voronoi tessellations of simplified distributions containing edges, we propose several algorithms for tagging the Voronoi cells in the vicinity of kinematic edges in real data and show that the efficiency of our methods is improved by the addition of a few Voronoi relaxation steps via Lloyd's method. Our results suggest specifically that Voronoi-based methods should be useful for relatively model-independent edge detection, and, more generally, that the wider adaptation of Voronoi tessellations may be useful in collider physics.

  5. Enhancement of Kinematic Accelerations by Wavenumber Correlation Filtering

    PubMed Central

    Hong, Chang-Ki; Kwon, Jay Hyoun

    2016-01-01

    To obtain kinematic accelerations with high accuracy and reliability, multiple Global Positioning System (GPS) receivers with a single antenna can be used for airborne gravimetry. The data collected from each receiver can be processed for kinematic accelerations that may be combined using simple averaging. Here, however, uncorrelated errors from instrument errors in each receiver also will be included that degrade the final solutions. Therefore, in this study, the wavenumber correlation filter (WCF) is applied to extract only the higher positively correlated wavenumber components of the kinematic accelerations for the enhancement of the final solution. The in situ airborne GPS data from two receivers were wavenumber-correlation-filtered to show about 0.07835 Gal improvement in accuracy relative to the solution from the raw kinematic accelerations. PMID:27608026

  6. Correlation Between University Students' Kinematic Achievement and Learning Styles

    NASA Astrophysics Data System (ADS)

    Çirkinoǧlu, A. G.; Dem&ircidot, N.

    2007-04-01

    In the literature, some researches on kinematics revealed that students have many difficulties in connecting graphs and physics. Also some researches showed that the method used in classroom affects students' further learning. In this study the correlation between university students' kinematics achieve and learning style are investigated. In this purpose Kinematics Achievement Test and Learning Style Inventory were applied to 573 students enrolled in general physics 1 courses at Balikesir University in the fall semester of 2005-2006. Kinematics Test, consists of 12 multiple choose and 6 open ended questions, was developed by researchers to assess students' understanding, interpreting, and drawing graphs. Learning Style Inventory, a 24 items test including visual, auditory, and kinesthetic learning styles, was developed and used by Barsch. The data obtained from in this study were analyzed necessary statistical calculations (T-test, correlation, ANOVA, etc.) by using SPSS statistical program. Based on the research findings, the tentative recommendations are made.

  7. Randomized SUSAN edge detector

    NASA Astrophysics Data System (ADS)

    Qu, Zhi-Guo; Wang, Ping; Gao, Ying-Hui; Wang, Peng

    2011-11-01

    A speed up technique for the SUSAN edge detector based on random sampling is proposed. Instead of sliding the mask pixel by pixel on an image as the SUSAN edge detector does, the proposed scheme places the mask randomly on pixels to find edges in the image; we hereby name it randomized SUSAN edge detector (R-SUSAN). Specifically, the R-SUSAN edge detector adopts three approaches in the framework of random sampling to accelerate a SUSAN edge detector: procedure integration of response computation and nonmaxima suppression, reduction of unnecessary processing for obvious nonedge pixels, and early termination. Experimental results demonstrate the effectiveness of the proposed method.

  8. O-star kinematics

    SciTech Connect

    Karimova, D.K.; Pavlovskaya, E.D.

    1984-01-01

    Proper motions determined by the authors are utilized to study the kinematics of 79 O-type stars at distance r< or =2.5 kpc. The sample is divided into two groups, having space-velocity dispersions tau/sub I/roughly-equal10 km/sec, sigma/sub II/roughly-equal35 km/sec. Solutions for the velocity-field parameters for group I yield a galactic angular rotation speed ..omega../sub 0/ = 24.9 km sec/sup -1/ kpc/sup -1/ at the sun (for R/sub 0/ = 10.0 kpc) and an Oort constant A = 12.2 km sec/sup -1/ kpc/sup -1/. Most of the O stars exhibit a small z-velocity directed away from the galactic plane. The velocity-ellipsoid parameters and box-orbit elements are calculated.

  9. Rattlesnake strike behavior: kinematics

    PubMed

    Kardong; v

    1998-03-01

    The predatory behavior of rattlesnakes includes many distinctive preparatory phases leading to an extremely rapid strike, during which venom is injected. The rodent prey is then rapidly released, removing the snake's head from retaliation by the prey. The quick action of the venom makes possible the recovery of the dispatched prey during the ensuing poststrike period. The strike is usually completed in less than 0.5 s, placing a premium on an accurate strike that produces no significant errors in fang placement that could result in poor envenomation and subsequent loss of the prey. To clarify the basis for effective strike performance, we examined the basic kinematics of the rapid strike using high-speed film analysis. We scored numerous strike variables. Four major results were obtained. (1) Neurosensory control of the strike is based primarily upon sensory inputs via the eyes and facial pits to launch the strike, and upon tactile stimuli after contact. Correction for errors in targeting occurs not by a change in strike trajectory, but by fang repositioning after the jaws have made contact with the prey. (2) The rattlesnake strike is based upon great versatility and variation in recruitment of body segments and body postures. (3) Forces generated during acceleration of the head are transferred to posterior body sections to decelerate the head before contact with the prey, thereby reducing impact forces upon the snake's jaws. (4) Body acceleration is based on two patterns of body displacement, one in which acute sections of the body open like a gate, the other in which body segments flow around postural curves similar to movements seen during locomotion. There is one major implication of these results: recruitment of body segments, launch postures and kinematic features of the strike may be quite varied from strike to strike, but the overall predatory success of each strike by a rattlesnake is very consistent.

  10. Kinematic foot types in youth with equinovarus secondary to hemiplegia

    PubMed Central

    Krzak, Joseph J.; Corcos, Daniel M.; Damiano, Diane L.; Graf, Adam; Hedeker, Donald; Smith, Peter A.; Harris, Gerald F.

    2015-01-01

    Background Elevated kinematic variability of the foot and ankle segments exists during gait among individuals with equinovarus secondary to hemiplegic cerebral palsy (CP). Clinicians have previously addressed such variability by developing classification schemes to identify subgroups of individuals based on their kinematics. Objective To identify kinematic subgroups among youth with equinovarus secondary to CP using 3-dimensional multi-segment foot and ankle kinematics during locomotion as inputs for principal component analysis (PCA), and K-means cluster analysis. Methods In a single assessment session, multi-segment foot and ankle kinematics using the Milwaukee Foot Model (MFM) were collected in 24 children/adolescents with equinovarus and 20 typically developing children/adolescents. Results PCA was used as a data reduction technique on 40 variables. K-means cluster analysis was performed on the first six principal components (PCs) which accounted for 92% of the variance of the dataset. The PCs described the location and plane of involvement in the foot and ankle. Five distinct kinematic subgroups were identified using K-means clustering. Participants with equinovarus presented with variable involvement ranging from primary hindfoot or forefoot deviations to deformtiy that included both segments in multiple planes. Conclusion This study provides further evidence of the variability in foot characteristics associated with equinovarus secondary to hemiplegic CP. These findings would not have been detected using a single segment foot model. The identification of multiple kinematic subgroups with unique foot and ankle characteristics has the potential to improve treatment since similar patients within a subgroup are likely to benefit from the same intervention(s). PMID:25467429

  11. Failure During Sheared Edge Stretching

    NASA Astrophysics Data System (ADS)

    Levy, B. S.; van Tyne, C. J.

    2008-12-01

    Failure during sheared edge stretching of sheet steels is a serious concern, especially in advanced high-strength steel (AHSS) grades. The shearing process produces a shear face and a zone of deformation behind the shear face, which is the shear-affected zone (SAZ). A failure during sheared edge stretching depends on prior deformation in the sheet, the shearing process, and the subsequent strain path in the SAZ during stretching. Data from laboratory hole expansion tests and hole extrusion tests for multiple lots of fourteen grades of steel were analyzed. The forming limit curve (FLC), regression equations, measurement uncertainty calculations, and difference calculations were used in the analyses. From these analyses, an assessment of the primary factors that contribute to the fracture during sheared edge stretching was made. It was found that the forming limit strain with consideration of strain path in the SAZ is a major factor that contributes to the failure of a sheared edge during stretching. Although metallurgical factors are important, they appear to play a somewhat lesser role.

  12. CME Kinematics and Dynamics

    NASA Astrophysics Data System (ADS)

    Lin, C.-H.; Gallagher, P. T.

    The goal of this study is to investigate the driving mechanisms of CMEs and to infer the magnetic field properties at the onset of the instability. We use EIT 195 Å images and LASCO white-light coronagraph data of a CME event that occurred on 17 December 2006. It was a long-duration event, and was associated with an occulted C2.1 class flare. To determine the driving mechanism, we quantitatively and qualitatively compared the observationally obtained kinematic evolution with that predicted by three CME models: the breakout model (BO, see Antiochos et al. 1999; Lynch et al. 2008; DeVore and Antiochos 2008), the catastrophe model (CM, see Priest and Forbes 2000), and the toroidal instability model (TI, see Chen 1989; Kliem and Török 2006). Our results indicate that this CME is best represented by the CM model. We infer that, at the onset of the instability, the Alfvén speed is approximately 120 km s-1 and the height of the flux rope is roughly 100-200Mm. These parameter values are related to the magnetic environment and the loop geometry and can be used to infer the magnetic condition at the onset of the eruption.We intend to submit the full analysis to A&A.

  13. 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.

  14. 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.

  15. Bat flight: aerodynamics, kinematics and flight morphology.

    PubMed

    Hedenström, Anders; Johansson, L Christoffer

    2015-03-01

    Bats evolved the ability of powered flight more than 50 million years ago. The modern bat is an efficient flyer and recent research on bat flight has revealed many intriguing facts. By using particle image velocimetry to visualize wake vortices, both the magnitude and time-history of aerodynamic forces can be estimated. At most speeds the downstroke generates both lift and thrust, whereas the function of the upstroke changes with forward flight speed. At hovering and slow speed bats use a leading edge vortex to enhance the lift beyond that allowed by steady aerodynamics and an inverted wing during the upstroke to further aid weight support. The bat wing and its skeleton exhibit many features and control mechanisms that are presumed to improve flight performance. Whereas bats appear aerodynamically less efficient than birds when it comes to cruising flight, they have the edge over birds when it comes to manoeuvring. There is a direct relationship between kinematics and the aerodynamic performance, but there is still a lack of knowledge about how (and if) the bat controls the movements and shape (planform and camber) of the wing. Considering the relatively few bat species whose aerodynamic tracks have been characterized, there is scope for new discoveries and a need to study species representing more extreme positions in the bat morphospace.

  16. Tensor networks from kinematic space

    DOE PAGES

    Czech, Bartlomiej; Lamprou, Lampros; McCandlish, Samuel; ...

    2016-07-20

    We point out that the MERA network for the ground state of a 1+1-dimensional conformal field theory has the same structural features as kinematic space — the geometry of CFT intervals. In holographic theories kinematic space becomes identified with the space of bulk geodesics studied in integral geometry. We argue that in these settings MERA is best viewed as a discretization of the space of bulk geodesics rather than of the bulk geometry itself. As a test of this kinematic proposal, we compare the MERA representation of the thermofield-double state with the space of geodesics in the two-sided BTZ geometry,more » obtaining a detailed agreement which includes the entwinement sector. In conclusion, we discuss how the kinematic proposal can be extended to excited states by generalizing MERA to a broader class of compression networks.« less

  17. Tensor networks from kinematic space

    SciTech Connect

    Czech, Bartlomiej; Lamprou, Lampros; McCandlish, Samuel; Sully, James

    2016-07-20

    We point out that the MERA network for the ground state of a 1+1-dimensional conformal field theory has the same structural features as kinematic space — the geometry of CFT intervals. In holographic theories kinematic space becomes identified with the space of bulk geodesics studied in integral geometry. We argue that in these settings MERA is best viewed as a discretization of the space of bulk geodesics rather than of the bulk geometry itself. As a test of this kinematic proposal, we compare the MERA representation of the thermofield-double state with the space of geodesics in the two-sided BTZ geometry, obtaining a detailed agreement which includes the entwinement sector. In conclusion, we discuss how the kinematic proposal can be extended to excited states by generalizing MERA to a broader class of compression networks.

  18. Kinematic precision of gear trains

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1982-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory.

  19. Kinematic precision of gear trains

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1983-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory. Previously announced in STAR as N82-32733

  20. Improved kinematic options in ALEGRA.

    SciTech Connect

    Farnsworth, Grant V.; Robinson, Allen Conrad

    2003-12-01

    Algorithms for higher order accuracy modeling of kinematic behavior within the ALEGRA framework are presented. These techniques improve the behavior of the code when kinematic errors are found, ensure orthonormality of the rotation tensor at each time step, and increase the accuracy of the Lagrangian stretch and rotation tensor update algorithm. The implementation of these improvements in ALEGRA is described. A short discussion of issues related to improving the accuracy of the stress update procedures is also included.

  1. Aero-optimum hovering kinematics.

    PubMed

    Nabawy, Mostafa R A; Crowther, William J

    2015-08-07

    Hovering flight for flapping wing vehicles requires rapid and relatively complex reciprocating movement of a wing relative to a stationary surrounding fluid. This note develops a compact analytical aero-kinematic model that can be used for optimization of flapping wing kinematics against aerodynamic criteria of effectiveness (maximum lift) and efficiency (minimum power for a given amount of lift). It can also be used to make predictions of required flapping frequency for a given geometry and basic aerodynamic parameters. The kinematic treatment is based on a consolidation of an existing formulation that allows explicit derivation of flapping velocity for complex motions whereas the aerodynamic model is based on existing quasi-steady analysis. The combined aero-kinematic model provides novel explicit analytical expressions for both lift and power of a hovering wing in a compact form that enables exploration of a rich kinematic design space. Good agreement is found between model predictions of flapping frequency and observed results for a number of insects and optimal hovering kinematics identified using the model are consistent with results from studies using higher order computational models. For efficient flight, the flapping angle should vary using a triangular profile in time leading to a constant velocity flapping motion, whereas for maximum effectiveness the shape of variation should be sinusoidal. For both cases the wing pitching motion should be rectangular such that pitch change at stroke reversal is as rapid as possible.

  2. Edge enhancement improves disruptive camouflage by emphasising false edges and creating pictorial relief

    PubMed Central

    Egan, John; Sharman, Rebecca J.; Scott-Brown, Kenneth C.; Lovell, Paul George

    2016-01-01

    Disruptive colouration is a visual camouflage composed of false edges and boundaries. Many disruptively camouflaged animals feature enhanced edges; light patches are surrounded by a lighter outline and/or a dark patches are surrounded by a darker outline. This camouflage is particularly common in amphibians, reptiles and lepidopterans. We explored the role that this pattern has in creating effective camouflage. In a visual search task utilising an ultra-large display area mimicking search tasks that might be found in nature, edge enhanced disruptive camouflage increases crypsis, even on substrates that do not provide an obvious visual match. Specifically, edge enhanced camouflage is effective on backgrounds both with and without shadows; i.e. this is not solely due to background matching of the dark edge enhancement element with the shadows. Furthermore, when the dark component of the edge enhancement is omitted the camouflage still provided better crypsis than control patterns without edge enhancement. This kind of edge enhancement improved camouflage on all background types. Lastly, we show that edge enhancement can create a perception of multiple surfaces. We conclude that edge enhancement increases the effectiveness of disruptive camouflage through mechanisms that may include the improved disruption of the object outline by implying pictorial relief. PMID:27922058

  3. Edge enhancement improves disruptive camouflage by emphasising false edges and creating pictorial relief.

    PubMed

    Egan, John; Sharman, Rebecca J; Scott-Brown, Kenneth C; Lovell, Paul George

    2016-12-06

    Disruptive colouration is a visual camouflage composed of false edges and boundaries. Many disruptively camouflaged animals feature enhanced edges; light patches are surrounded by a lighter outline and/or a dark patches are surrounded by a darker outline. This camouflage is particularly common in amphibians, reptiles and lepidopterans. We explored the role that this pattern has in creating effective camouflage. In a visual search task utilising an ultra-large display area mimicking search tasks that might be found in nature, edge enhanced disruptive camouflage increases crypsis, even on substrates that do not provide an obvious visual match. Specifically, edge enhanced camouflage is effective on backgrounds both with and without shadows; i.e. this is not solely due to background matching of the dark edge enhancement element with the shadows. Furthermore, when the dark component of the edge enhancement is omitted the camouflage still provided better crypsis than control patterns without edge enhancement. This kind of edge enhancement improved camouflage on all background types. Lastly, we show that edge enhancement can create a perception of multiple surfaces. We conclude that edge enhancement increases the effectiveness of disruptive camouflage through mechanisms that may include the improved disruption of the object outline by implying pictorial relief.

  4. In vivo healthy knee kinematics during dynamic full flexion.

    PubMed

    Hamai, Satoshi; Moro-oka, Taka-aki; Dunbar, Nicholas J; Miura, Hiromasa; Iwamoto, Yukihide; Banks, Scott A

    2013-01-01

    Healthy knee kinematics during dynamic full flexion were evaluated using 3D-to-2D model registration techniques. Continuous knee motions were recorded during full flexion in a lunge from 85° to 150°. Medial and lateral tibiofemoral contacts and femoral internal-external and varus-valgus rotations were analyzed as a function of knee flexion angle. The medial tibiofemoral contact translated anteroposteriorly, but remained on the center of the medial compartment. On the other hand, the lateral tibiofemoral contact translated posteriorly to the edge of the tibial surface at 150° flexion. The femur exhibited external and valgus rotation relative to the tibia over the entire activity and reached 30° external and 5° valgus rotations at 150° flexion. Kinematics' data during dynamic full flexion may provide important insight as to the designing of high-flexion total knee prostheses.

  5. Kinematic Hardening: Characterization, Modeling and Impact on Springback Prediction

    SciTech Connect

    Alves, J. L.; Bouvier, S.; Jomaa, M.; Billardon, R.

    2007-05-17

    The constitutive modeling of the materials' mechanical behavior, usually carried out using a phenomenological constitutive model, i.e., a yield criterion associated to the isotropic and kinematic hardening laws, is of paramount importance in the FEM simulation of the sheet metal forming processes, as well as in the springback prediction. Among others, the kinematic behavior of the yield surface plays an essential role, since it is indispensable to describe the Bauschinger effect, i.e., the materials' answer to the multiple tension-compression cycles to which material points are submitted during the forming process. Several laws are usually used to model and describe the kinematic hardening, namely: a) the Prager's law, which describes a linear evolution of the kinematic hardening with the plastic strain rate tensor b) the Frederick-Armstrong non-linear kinematic hardening, basically a non-linear law with saturation; and c) a more advanced physically-based law, similar to the previous one but sensitive to the strain path changes. In the present paper a mixed kinematic hardening law (linear + non-linear behavior) is proposed and its implementation into a static fully-implicit FE code is described. The material parameters identification for sheet metals using different strategies, and the classical Bauschinger loading tests (i.e. in-plane forward and reverse monotonic loading), are addressed, and their impact on springback prediction evaluated. Some numerical results concerning the springback prediction of the Numisheet'05 Benchmark no. 3 are briefly presented to emphasize the importance of a correct modeling and identification of the kinematic hardening behavior.

  6. Are static and dynamic kinematics comparable after total knee arthroplasty?

    PubMed

    Saevarsson, Stefan K; Romeo, Carolina I; Anglin, Carolyn

    2013-04-05

    Knee kinematics provide information about how the femoral, tibial and patellar bones or prosthetic components move relative to each other. Accurate knowledge of kinematics is valuable for implant design, comparisons between designs or surgical techniques, and to identify differences between patients with good and poor outcomes. Both static and dynamic imaging techniques have been used to evaluate kinematics. In general, static imaging is used to capture better quality images or to capture views that cannot be acquired by dynamic imaging, whereas dynamic imaging is used to capture real-life movements. How well static kinematics represent dynamic kinematics is subject to frequent debate and has not been adequately addressed, especially after total knee arthroplasty (TKA). We compared the static and dynamic weightbearing kinematics of 10 female subjects after TKA. Using the same clinical scanner for both methods, static images were taken using our standard protocol, sequential-biplane radiographs at multiple flexion angles, as well as with dynamic video fluoroscopy during a step up activity. The static method can reliably measure all 12 degrees of freedom (DOF) after TKA, however only seven were compared due to the poorer out-of-plane reliability in the single-plane dynamic imaging. No differences were found between the static and dynamic kinematics for nine out of ten subjects. For one subject, however, a difference of 5-8° in internal/external tibial rotation was found. The research question, study purpose and the advantages and disadvantages of each method need to be considered when determining which imaging method to use.

  7. Study of human body: Kinematics and kinetics of a martial arts (Silat) performers using 3D-motion capture

    NASA Astrophysics Data System (ADS)

    Soh, Ahmad Afiq Sabqi Awang; Jafri, Mohd Zubir Mat; Azraai, Nur Zaidi

    2015-04-01

    The Interest in this studies of human kinematics goes back very far in human history drove by curiosity or need for the understanding the complexity of human body motion. To find new and accurate information about the human movement as the advance computing technology became available for human movement that can perform. Martial arts (silat) were chose and multiple type of movement was studied. This project has done by using cutting-edge technology which is 3D motion capture to characterize and to measure the motion done by the performers of martial arts (silat). The camera will detect the markers (infrared reflection by the marker) around the performer body (total of 24 markers) and will show as dot in the computer software. The markers detected were analyzing using kinematic kinetic approach and time as reference. A graph of velocity, acceleration and position at time,t (seconds) of each marker was plot. Then from the information obtain, more parameters were determined such as work done, momentum, center of mass of a body using mathematical approach. This data can be used for development of the effectiveness movement in martial arts which is contributed to the people in arts. More future works can be implemented from this project such as analysis of a martial arts competition.

  8. Supersonic Leading Edge Receptivity

    NASA Technical Reports Server (NTRS)

    Maslov, Anatoly A.

    1998-01-01

    This paper describes experimental studies of leading edge boundary layer receptivity for imposed stream disturbances. Studies were conducted in the supersonic T-325 facility at ITAM and include data for both sharp and blunt leading edges. The data are in agreement with existing theory and should provide guidance for the development of more complete theories and numerical computations of this phenomena.

  9. 2D kinematic signatures of boxy/peanut bulges

    NASA Astrophysics Data System (ADS)

    Iannuzzi, Francesca; Athanassoula, E.

    2015-07-01

    We study the imprints of boxy/peanut structures on the 2D line-of-sight kinematics of simulated disc galaxies. The models under study belong to a family with varying initial gas fraction and halo triaxiality, plus few other control runs with different structural parameters; the kinematic information was extracted using the Voronoi-binning technique and parametrized up to the fourth order of a Gauss-Hermite series. Building on a previous work for the long-slit case, we investigate the 2D kinematic behaviour in the edge-on projection as a function of the boxy/peanut strength and position angle; we find that for the strongest structures the highest moments show characteristic features away from the mid-plane in a range of position angles. We also discuss the masking effect of a classical bulge and the ambiguity in discriminating kinematically this spherically symmetric component from a boxy/peanut bulge seen end-on. Regarding the face-on case, we extend existing results to encompass the effect of a second buckling and find that this phenomenon spurs an additional set of even deeper minima in the fourth moment. Finally, we show how the results evolve when inclining the disc away from perfectly edge-on and face-on. The behaviour of stars born during the course of the simulations is discussed and confronted to that of the pre-existing disc. The general aim of our study is providing a handle to identify boxy/peanut structures and their properties in latest generation Integral Field Unit observations of nearby disc galaxies.

  10. Continuum Gyrokinetic Edge New Technology

    SciTech Connect

    Dorr, M. R.; Hittinger, J. A.; Dorf, M.; Cohen, R.; Ghosh, D.; Lee, W.; Reynolds, C.

    2016-05-02

    COGENT is a simulation code that models the plasma evolution in the edge region of a tokamak fusion reactor, from the open field line scrape-off layer, across the separatrix, and into the core. The model is based on the 4D gyrokinetic closure of the kinetic equations for a plasma coupled to an electrostatic potential field. The background magnetic field is prescribed either analytically or generated from experimental data, and the grid is aligned with magnetic flux surfaces. Multiple collision operator options are provided, from Krook to fully nonlinear Fokker-Planck.

  11. Kinematics of KPG 390

    NASA Astrophysics Data System (ADS)

    Repetto, P.; Rosado, M.; Gabbasov, R.; Fuentes-Carrera, I.

    2010-06-01

    In this work we present scanning Fabry-Perot Hα observations of the isolated interacting galaxy pair NGC 5278/9 obtained with the PUMA Fabry-Perot interferometer. We derived velocity fields, various kinematic parameters and rotation curves for both galaxies. Our kinematical results together with the fact that dust lanes have been detected in both galaxies, as well as the analysis of surface brightness profiles along the minor axis, allowed us to determine that both components of the interacting pair are trailing spirals.

  12. KINEMATIC AND PHOTOMETRIC EVIDENCE FOR A BAR IN NGC 2683

    SciTech Connect

    Kuzio de Naray, Rachel; Zagursky, Matthew J.; McGaugh, Stacy S. E-mail: mzagursk@umd.edu

    2009-10-15

    We present optical long-slit and SparsePak Integral Field Unit emission line spectroscopy along with optical broadband and near-IR images of the edge-on spiral galaxy NGC 2683. We find a multi-valued, figure-of-eight velocity structure in the inner 45'' of the long-slit spectrum and twisted isovelocity contours in the velocity field. We also find, regardless of wavelength, that the galaxy isophotes are boxy. We argue that taken together, these kinematic and photometric features are evidence for the presence of a bar in NGC 2683. We use our data to constrain the orientation and strength of the bar.

  13. Agile robotic edge finishing

    SciTech Connect

    Powell, M.

    1996-08-01

    Edge finishing processes have seemed like ideal candidates for automation. Most edge finishing processes are unpleasant, dangerous, tedious, expensive, not repeatable and labor intensive. Estimates place the cost of manual edge finishing processes at 12% of the total cost of fabricating precision parts. For small, high precision parts, the cost of hand finishing may be as high as 305 of the total part cost. Up to 50% of this cost could be saved through automation. This cost estimate includes the direct costs of edge finishing: the machining hours required and the 30% scrap and rework rate after manual finishing. Not included in these estimates are the indirect costs resulting from cumulative trauma disorders and retraining costs caused by the high turnover rate for finishing jobs.. Despite the apparent economic advantages, edge finishing has proven difficult to automate except in low precision and/or high volume production environments. Finishing automation systems have not been deployed successfully in Department of Energy defense programs (DOE/DP) production, A few systems have been attempted but have been subsequently abandoned for traditional edge finishing approaches: scraping, grinding, and filing the edges using modified dental tools and hand held power tools. Edge finishing automation has been an elusive but potentially lucrative production enhancement. The amount of time required for reconfiguring workcells for new parts, the time required to reprogram the workcells to finish new parts, and automation equipment to respond to fixturing errors and part tolerances are the most common reasons cited for eliminating automation as an option for DOE/DP edge finishing applications. Existing automated finishing systems have proven to be economically viable only where setup and reprogramming costs are a negligible fraction of overall production costs.

  14. Distributed electromechanical actuation system design for a morphing trailing edge wing

    NASA Astrophysics Data System (ADS)

    Dimino, I.; Diodati, G.; Concilio, A.; Volovick, A.; Zivan, L.

    2016-04-01

    Next-generation flight control actuation technology will be based on "more electric" concepts to ensure benefits in terms of efficiency, weight and maintenance. This paper is concerned with the design of an un-shafted distributed servo-electromechanical actuation system, suited for morphing trailing edge wings of large commercial aircraft. It aims at producing small wing camber variations in the range between -5° and +5° in cruise, to enable aerodynamic efficiency improvements. The deployment kinematics is based on multiple "direct-drive" actuation, each made of light-weight compact lever mechanisms, rigidly connected to compliant ribs and sustained by load-bearing motors. Navier-Stokes computations are performed to estimate the pressure distribution over the interested wing region and the resulting hinge moments. These transfer to the primary structure via the driving mechanism. An electro-mechanical Matlab/Simulink model of the distributed actuation architecture is developed and used as a design tool, to preliminary evaluate the complete system performance. Implementing a multi-shaft strategy, each actuator is sized for the torque acting on the respective adaptive rib, following the effect of both the aerodynamic pressure and the morphing skin stiffness. Elastic trailing edge rotations and power needs are evaluated in operative conditions. Focus is finally given to the key challenges of the proposed concept: targeting quantifiable performance improvements while being compliant to the demanding requirements in terms of reliability and safety.

  15. The digital step edge

    NASA Technical Reports Server (NTRS)

    Haralick, R. M.

    1982-01-01

    The facet model was used to accomplish step edge detection. The essence of the facet model is that any analysis made on the basis of the pixel values in some neighborhood has its final authoritative interpretation relative to the underlying grey tone intensity surface of which the neighborhood pixel values are observed noisy samples. Pixels which are part of regions have simple grey tone intensity surfaces over their areas. Pixels which have an edge in them have complex grey tone intensity surfaces over their areas. Specially, an edge moves through a pixel only if there is some point in the pixel's area having a zero crossing of the second directional derivative taken in the direction of a non-zero gradient at the pixel's center. To determine whether or not a pixel should be marked as a step edge pixel, its underlying grey tone intensity surface was estimated on the basis of the pixels in its neighborhood.

  16. Kinematic analysis of the ARID manipulator

    NASA Technical Reports Server (NTRS)

    Doty, Keith L

    1992-01-01

    The kinematic structure of the ARID manipulator lends itself to simple forward and inverse kinematics analysis. The purpose of this paper is to fully document and verify an existing analysis. The symbolic software package MATHEMATICA was used to produce and verify the equations presented here. In the analysis to follow, the standard Devenit-Hartenberg kinematic parameters of the ARID were employed.

  17. Deployable antenna kinematics using tensegrity structure design

    NASA Astrophysics Data System (ADS)

    Knight, Byron Franklin

    With vast changes in spacecraft development over the last decade, a new, cheaper approach was needed for deployable kinematic systems such as parabolic antenna reflectors. Historically, these mesh-surface reflectors have resembled folded umbrellas, with incremental redesigns utilized to save packaging size. These systems are typically over-constrained designs, the assumption being that high reliability necessary for space operations requires this level of conservatism. But with the rapid commercialization of space, smaller launch platforms and satellite buses have demanded much higher efficiency from all space equipment than can be achieved through this incremental approach. This work applies an approach called tensegrity to deployable antenna development. Kenneth Snelson, a student of R. Buckminster Fuller, invented Tensegrity structures in 1948. Such structures use a minimum number of compression members (struts); stability is maintain using tension members (ties). The novelty introduced in this work is that the ties are elastic, allowing the struts to extend or contract, and in this way changing the surface of the antenna. Previously, the University of Florida developed an approach to quantify the stability and motion of parallel manipulators. This approach was applied to deployable, tensegrity, antenna structures. Based on the kinematic analyses for the 3-3 (octahedron) and 4-4 (square anti-prism) structures, the 6-6 (hexagonal anti-prism) analysis was completed which establishes usable structural parameters. The primary objective for this work was to prove the stability of this class of deployable structures, and their potential application to space structures. The secondary objective is to define special motions for tensegrity antennas, to meet the subsystem design requirements, such as addressing multiple antenna-feed locations. This work combines the historical experiences of the artist (Snelson), the mathematician (Ball), and the space systems engineer

  18. The Edge supersonic transport

    NASA Technical Reports Server (NTRS)

    Agosta, Roxana; Bilbija, Dushan; Deutsch, Marc; Gallant, David; Rose, Don; Shreve, Gene; Smario, David; Suffredini, Brian

    1992-01-01

    As intercontinental business and tourism volumes continue their rapid expansion, the need to reduce travel times becomes increasingly acute. The Edge Supersonic Transport Aircraft is designed to meet this demand by the year 2015. With a maximum range of 5750 nm, a payload of 294 passengers and a cruising speed of M = 2.4, The Edge will cut current international flight durations in half, while maintaining competitive first class, business class, and economy class comfort levels. Moreover, this transport will render a minimal impact upon the environment, and will meet all Federal Aviation Administration Part 36, Stage III noise requirements. The cornerstone of The Edge's superior flight performance is its aerodynamically efficient, dual-configuration design incorporating variable-geometry wingtips. This arrangement combines the benefits of a high aspect ratio wing at takeoff and low cruising speeds with the high performance of an arrow-wing in supersonic cruise. And while the structural weight concerns relating to swinging wingtips are substantial, The Edge looks to ever-advancing material technologies to further increase its viability. Heeding well the lessons of the past, The Edge design holds economic feasibility as its primary focus. Therefore, in addition to its inherently superior aerodynamic performance, The Edge uses a lightweight, largely windowless configuration, relying on a synthetic vision system for outside viewing by both pilot and passengers. Additionally, a fly-by-light flight control system is incorporated to address aircraft supersonic cruise instability. The Edge will be produced at an estimated volume of 400 aircraft and will be offered to airlines in 2015 at $167 million per transport (1992 dollars).

  19. The kinematics of σ-drop bulges from spectral synthesis modelling of a hydrodynamical simulation

    NASA Astrophysics Data System (ADS)

    Portaluri, Elisa; Debattista, Victor P.; Fabricius, Maximillian; Cole, David R.; Corsini, Enrico M.; Drory, Niv; Rowe, Andrew; Morelli, Lorenzo; Pizzella, Alessandro; Dalla Bontà, Elena

    2017-01-01

    A minimum in stellar velocity dispersion is often observed in the central regions of disc galaxies. To investigate the origin of this feature, known as a σ-drop, we analyse the stellar kinematics of a high-resolution N-body + smooth particle hydrodynamical simulation, which models the secular evolution of an unbarred disc galaxy. We compared the intrinsic mass-weighted kinematics to the recovered luminosity-weighted ones. The latter were obtained by analysing synthetic spectra produced by a new code, SYNTRA, that generates synthetic spectra by assigning a stellar population synthesis model to each star particle based on its age and metallicity. The kinematics were derived from the synthetic spectra as in real spectra to mimic the kinematic analysis of real galaxies. We found that the recovered luminosity-weighted kinematics in the centre of the simulated galaxy are biased to higher rotation velocities and lower velocity dispersions due to the presence of young stars in a thin and kinematically cool disc, and are ultimately responsible for the σ-drop. Our procedure for building mock observations and thus recovering the luminosity-weighted kinematics of the stars in a galaxy simulation is a powerful tool that can be applied to a variety of scientific questions, such as multiple stellar populations in kinematically-decoupled cores and counter-rotating components, and galaxies with both thick and thin disc components.

  20. A Geometric Framework for the Kinematics of Crystals With Defects

    DTIC Science & Technology

    2006-02-01

    normal to a) shown in figure 4—i.e. the area of the parallelogram enclosed by uðAÞ, uðBÞ, vðAÞ, and vðCÞ, with C a third location on the deformed ...framework capable of describing the finite deformation kinematics of several classes of defects prevalent in metallic crystals. Our treatment relies upon...length scale dependent, three-term multiplicative decomposition of the deformation gradient is suggested, with terms representing recoverable

  1. Galaxy simulations: Kinematics and mock observations

    NASA Astrophysics Data System (ADS)

    Moody, Christopher E.

    2013-08-01

    There are six topics to my thesis, which are: (1) slow rotator production in varied simulation schemes and kinematically decoupled cores and twists in those simulations, (2) the change in number of clumps in radiation pressure and no-radiation pressure simulations, (3) Sunrise experiments and failures including UVJ color-color dust experiments and UVbeta slopes, (4) the Sunrise image pipeline and algorithms. Cosmological simulations of have typically produced too many stars at early times. We find that the additional radiation pressure (RP) feedback suppresses star formation globally by a factor of ~ 3. Despite this reduction, the simulation still overproduces stars by a factor of ~ 2 with respect to the predictions provided by abundance matching methods. In simulations with RP the number of clumps falls dramatically. However, only clumps with masses Mclump/Mdisk ≤ 8% are impacted by the inclusion of RP, and clump counts above this range are comparable. Above this mass, the difference between and RP and no-RP contrast ratios diminishes. If we restrict our selection to galaxies hosting at least a single clump above this mass range then clump numbers, contrast ratios, survival fractions and total clump masses show little discrepancy between RP and no-RP simulations. By creating mock Hubble Space Telescope observations we find that the number of clumps is slightly reduced in simulations with RP. We demonstrate that clumps found in any single gas, stellar, or mock observation image are not necessarily clumps found in another map, and that there are few clumps common to multiple maps. New kinematic observations from ATLAS3D have highlighted the need to understand the evolutionary mechanism leading to a spectrum of fast-rotator and slow-rotators in early-type galaxies. We address the formation of slow and fast rotators through a series of controlled, comprehensive hydrodynamic simulations sampling idealized galaxy merger formation scenarios constructed from model

  2. Contact kinematics of biomimetic scales

    SciTech Connect

    Ghosh, Ranajay; Ebrahimi, Hamid; Vaziri, Ashkan

    2014-12-08

    Dermal scales, prevalent across biological groups, considerably boost survival by providing multifunctional advantages. Here, we investigate the nonlinear mechanical effects of biomimetic scale like attachments on the behavior of an elastic substrate brought about by the contact interaction of scales in pure bending using qualitative experiments, analytical models, and detailed finite element (FE) analysis. Our results reveal the existence of three distinct kinematic phases of operation spanning linear, nonlinear, and rigid behavior driven by kinematic interactions of scales. The response of the modified elastic beam strongly depends on the size and spatial overlap of rigid scales. The nonlinearity is perceptible even in relatively small strain regime and without invoking material level complexities of either the scales or the substrate.

  3. Kinematic Fitting of Detached Vertices

    SciTech Connect

    Mattione, Paul

    2007-05-01

    The eg3 experiment at the Jefferson Lab CLAS detector aims to determine the existence of the $\\Xi_{5}$ pentaquarks and investigate the excited $\\Xi$ states. Specifically, the exotic $\\Xi_{5}^{--}$ pentaquark will be sought by first reconstructing the $\\Xi^{-}$ particle through its weak decays, $\\Xi^{-}\\to\\pi^{-}\\Lambda$ and $\\Lambda\\to\\pi^{-}$. A kinematic fitting routine was developed to reconstruct the detached vertices of these decays, where confidence level cuts on the fits are used to remove background events. Prior to fitting these decays, the exclusive reaction $\\gamma D\\rightarrow pp\\pi^{-}$ was studied in order to correct the track measurements and covariance matrices of the charged particles. The $\\Lambda\\rightarrow p\\pi^{-}$ and $\\Xi^{-}\\to\\pi^{-}\\Lambda$ decays were then investigated to demonstrate that the kinematic fitting routine reconstructs the decaying particles and their detached vertices correctly.

  4. High Speed Edge Detection

    NASA Technical Reports Server (NTRS)

    Prokop, Norman F (Inventor)

    2015-01-01

    Analog circuits for detecting edges in pixel arrays are disclosed. A comparator may be configured to receive an all pass signal and a low pass signal for a pixel intensity in an array of pixels. A latch may be configured to receive a counter signal and a latching signal from the comparator. The comparator may be configured to send the latching signal to the latch when the all pass signal is below the low pass signal minus an offset. The latch may be configured to hold a last negative edge location when the latching signal is received from the comparator.

  5. High Speed Edge Detection

    NASA Technical Reports Server (NTRS)

    Prokop, Norman F (Inventor)

    2016-01-01

    Analog circuits for detecting edges in pixel arrays are disclosed. A comparator may be configured to receive an all pass signal and a low pass signal for a pixel intensity in an array of pixels. A latch may be configured to receive a counter signal and a latching signal from the comparator. The comparator may be configured to send the latching signal to the latch when the all pass signal is below the low pass signal minus an offset. The latch may be configured to hold a last negative edge location when the latching signal is received from the comparator.

  6. Influence of kinematic parameters on result efficiency in javelin throw.

    PubMed

    Saratlija, Predrag; Zagorac, Nebojsa; Babić, Vesna

    2013-05-01

    The aim of the research was to define the influence of the kinematic parameters in the javelin throw success in the top junior athletes at the European Junior Athletics Championships in Novi Sad. A set, consisting of 17 kinematic variables, was applied on a sample of 16 athletes, and the same variables were registered at the 2009 Novi Sad European Junior Championships. The criteria variable was the achieved throw length (javelin throw). The subjects were represented by 113 successful javelin throws. The results of the chosen kinematic variables correlation analysis showed the existence of multiple significant relations between the observed variables. Based on the observed kinematic variables correlation analysis, the next conclusion can be made: the javelin release speed has the most important role, followed by the fast front support leg placing. The results are expected and logical, and can be used in kinesiology practice, especially in the process of young throwers' technique learning and in development of motor abilities relevant for this athletic discipline.

  7. Of cilium and flagellum kinematics

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, Promode R.; Hansen, Joshua C.

    2009-11-01

    The kinematics of propulsion of small animals such as paramecium and spermatozoa is considered. Larger scale models of the cilium and flagellum have been built and a four-motor apparatus has been constructed to reproduce their known periodic motions. The cilium model has transverse deformational ability in one plane only, while the flagellum model has such ability in two planes. When the flagellum model is given a push-pull in one diametral plane, instead of transverse deflection in one plane, it forms a coil. Berg & Anderson's postulation (Nature 245 1973) that a flagellum rotates, is recalled. The kinematics of cilia of paramecium, of the whipping motion of the spermatozoa flagella, and of the flapping motion (rolling and pitching) of the pectoral fins of much larger animals such penguins, have been reproduced in the same basic paramecium apparatus. The results suggest that each of the tiny individual paramecium propulsors have the intrinsic dormant kinematic and structural building blocks to optimize into higher Reynolds number propulsors. A synthetic hypothesis on how small might have become large is animated.

  8. Kinematic top analyses at CDF

    SciTech Connect

    Cobal-Grassman, M.; CDF Collaboration

    1996-01-01

    We present an update of the top quark analysis using kinematic techniques in {rho}{ovr string {rho}} collisions at {radical}s = 1.8 TeV with the Collider Detector at Fermilab (CDF). We reported before on a study which used 19.3 pb{sup -1} of data from the 1992-93 collider run, but now we use a larger data sample of 67 pb{sup -1}. First, we analyze the total transverse energy of the hard collision in W+{ge}3 jet events, showing the likely presence of a t{ovr string t} component in the event sample. Next, we compare in more detail the kinematic structure of W+{ge}3 jet events with expectations for top pair production and with background processes, predominantly direct W+ jet production. We again find W+{ge}3 jet events which cannot be explained in terms of background, but show kinematic features as expected from top. These events also show evidence for beauty quarks. The findings confirm the observation of top events made earlier in the data of the 1992-93 collider run.

  9. Lumbar spine visualisation based on kinematic analysis from videofluoroscopic imaging.

    PubMed

    Zheng, Y; Nixon, M S; Allen, R

    2003-04-01

    Low back pain is a significant problem and its cost is enormous to society. However, diagnosis of the underlying causes remains problematic despite extensive study. Reasons for this arise from the deep-rooted situation of the spine and also from its structural complexity. Clinicians have to mentally convert 2-D image information into a 3-D form to gain a better understanding of structural integrity. Therefore, visualisation and animation may be helpful for understanding, diagnosis and for guiding therapy. Some low back pain originates from mechanical disorders, and study of the spine kinematics may provide an insight into the source of the problem. Digital videofluoroscopy was used in this study to provide 2-D image sequences of the spine in motion, but the images often suffer due to noise, exacerbated by the very low radiation dosage. Thus determining vertebrae position within the image sequence presents a considerable challenge. This paper describes a combination of spine kinematic measurements with a solid model of the human lumbar spine for visualisation of spine motion. Since determination of the spine kinematics provides the foundation and vertebral extraction is at the core, this is discussed in detail. Edge detection is a key feature of segmentation and it is shown that phase congruency performs better than most established methods with the rather low-grade image sequences from fluoroscopy. The Hough transform is then applied to determine the positions of vertebrae in each frame of a motion sequence. In the Hough transform, Fourier descriptors are used to represent the vertebral shapes. The results show that the Hough transform is a very promising technique for vertebral extraction from videofluoroscopic images. A dynamic visualisation package has been developed in order to view the moving lumbar spine from any angle and viewpoint. Wire frame models of the vertebrae were built by using CT images from the Visible Human Project and these models are scaled to

  10. Spiral galaxy HI models, rotation curves and kinematic classifications

    NASA Astrophysics Data System (ADS)

    Wiegert, Theresa B. V.

    Although galaxy interactions cause dramatic changes, galaxies also continue to form stars and evolve when they are isolated. The dark matter (DM) halo may influence this evolution since it generates the rotational behaviour of galactic disks which could affect local conditions in the gas. Therefore we study neutral hydrogen kinematics of non-interacting, nearby spiral galaxies, characterising their rotation curves (RC) which probe the DM halo; delineating kinematic classes of galaxies; and investigating relations between these classes and galaxy properties such as disk size and star formation rate (SFR). To generate the RCs, we use GalAPAGOS (by J. Fiege). My role was to test and help drive the development of this software, which employs a powerful genetic algorithm, constraining 23 parameters while using the full 3D data cube as input. The RC is here simply described by a tanh-based function which adequately traces the global RC behaviour. Extensive testing on artificial galaxies show that the kinematic properties of galaxies with inclination >40 degrees, including edge-on galaxies, are found reliably. Using a hierarchical clustering algorithm on parametrised RCs from 79 galaxies culled from literature generates a preliminary scheme consisting of five classes. These are based on three parameters: maximum rotational velocity, turnover radius and outer slope of the RC. To assess the relationship between DM content and the kinematic classes, we generate mass models for 10 galaxies from the THINGS and WHISP surveys, and J. Irwin's sample. In most cases mass models using GalAPAGOS RCs were similar to those using traditional "tilted-ring'' method RCs. The kinematic classes are mainly distinguished by their rotational velocity. We confirm correlations between increasing velocity and B-magnitude, optical disk size, and find earlier type galaxies among the strong rotators. SFR also increases with maximum rotational velocity. Given our limited subsample, we cannot discern a

  11. Swords with Blunt Edges

    ERIC Educational Resources Information Center

    Popham, W. James

    2004-01-01

    Many U.S. educators now wonder whether they're teachers or targets. This mentality stems from the specter of their school being sanctioned for failing the state accountability tests mandated under No Child Left Behind (NCLB). According to this author, most of those tests are like blunt-edged swords: They function badly in two directions. While…

  12. The Inner Urban Edge

    ERIC Educational Resources Information Center

    Ferebee, Ann; Carpenter, Edward K.

    1974-01-01

    In this article, renewal of the inner urban edge is discussed. Norfolk (Virginia) is attempting to blur the difference between old and new neighbor hoods through zoning and architectural controls. Cincinnati (Ohio) is developing an environmentally sound hillside design. Reading (Pennsylvania) is utilizing old railyards for greenbelts of hiking and…

  13. A synthetic genetic edge detection program.

    PubMed

    Tabor, Jeffrey J; Salis, Howard M; Simpson, Zachary Booth; Chevalier, Aaron A; Levskaya, Anselm; Marcotte, Edward M; Voigt, Christopher A; Ellington, Andrew D

    2009-06-26

    Edge detection is a signal processing algorithm common in artificial intelligence and image recognition programs. We have constructed a genetically encoded edge detection algorithm that programs an isogenic community of E. coli to sense an image of light, communicate to identify the light-dark edges, and visually present the result of the computation. The algorithm is implemented using multiple genetic circuits. An engineered light sensor enables cells to distinguish between light and dark regions. In the dark, cells produce a diffusible chemical signal that diffuses into light regions. Genetic logic gates are used so that only cells that sense light and the diffusible signal produce a positive output. A mathematical model constructed from first principles and parameterized with experimental measurements of the component circuits predicts the performance of the complete program. Quantitatively accurate models will facilitate the engineering of more complex biological behaviors and inform bottom-up studies of natural genetic regulatory networks.

  14. A Synthetic Genetic Edge Detection Program

    PubMed Central

    Tabor, Jeffrey J.; Salis, Howard; Simpson, Zachary B.; Chevalier, Aaron A.; Levskaya, Anselm; Marcotte, Edward M.; Voigt, Christopher A.; Ellington, Andrew D.

    2009-01-01

    Summary Edge detection is a signal processing algorithm common in artificial intelligence and image recognition programs. We have constructed a genetically encoded edge detection algorithm that programs an isogenic community of E.coli to sense an image of light, communicate to identify the light-dark edges, and visually present the result of the computation. The algorithm is implemented using multiple genetic circuits. An engineered light sensor enables cells to distinguish between light and dark regions. In the dark, cells produce a diffusible chemical signal that diffuses into light regions. Genetic logic gates are used so that only cells that sense light and the diffusible signal produce a positive output. A mathematical model constructed from first principles and parameterized with experimental measurements of the component circuits predicts the performance of the complete program. Quantitatively accurate models will facilitate the engineering of more complex biological behaviors and inform bottom-up studies of natural genetic regulatory networks. PMID:19563759

  15. Superpixel edges for boundary detection

    SciTech Connect

    Moya, Mary M.; Koch, Mark W.

    2016-07-12

    Various embodiments presented herein relate to identifying one or more edges in a synthetic aperture radar (SAR) image comprising a plurality of superpixels. Superpixels sharing an edge (or boundary) can be identified and one or more properties of the shared superpixels can be compared to determine whether the superpixels form the same or two different features. Where the superpixels form the same feature the edge is identified as an internal edge. Where the superpixels form two different features, the edge is identified as an external edge. Based upon classification of the superpixels, the external edge can be further determined to form part of a roof, wall, etc. The superpixels can be formed from a speckle-reduced SAR image product formed from a registered stack of SAR images, which is further segmented into a plurality of superpixels. The edge identification process is applied to the SAR image comprising the superpixels and edges.

  16. Shape of patch edges affects edge permeability for meadow voles.

    PubMed

    Nams, Vilis O

    2012-09-01

    Human development typically fragments natural habitats into patches, affecting population and metapopulation dynamics via changes in animal behavior. Emigration from one habitat patch to another has a large effect on population and metapopulation dynamics. One factor that affects emigration is permeability of patch edges. This study looks at the effects of edge shape (convex, concave, and straight) on edge permeability for meadow voles (Microtus pennsylvanicus).. I tested five hypotheses for responses of animal movement to patch shape: (1) neutral edge response; (2) edge attraction; (3) edge avoidance; (4) time-minimizing, in which an animal attempts to minimize the time spent in inhospitable matrix, and thus travels as far as possible in the patch before crossing the edge; and (5) protection, in which an animal attempts to maximize protection while in the inhospitable matrix by keeping the patch close by. These hypotheses were tested by an experimental manipulation of meadow vole habitats. A strip was mowed with different edge shapes through an old field, and vole response was measured by tracking plates. Voles crossed edges at concave treatments twice as often compared to convex and straight shapes. Hypotheses (2) and (5) were supported. Although edge attraction causes a passive effect of a decrease in edge-crossing at concavities, this effect was eclipsed by the active effect of voles choosing to cross at concavities. The results can be generalized to edge tortuosity in general. Conservation biologists should consider edge shapes when exploring the effects of habitat fragmentation on animal populations.

  17. Edge detection by nonlinear dynamics

    SciTech Connect

    Wong, Yiu-fai

    1994-07-01

    We demonstrate how the formulation of a nonlinear scale-space filter can be used for edge detection and junction analysis. By casting edge-preserving filtering in terms of maximizing information content subject to an average cost function, the computed cost at each pixel location becomes a local measure of edgeness. This computation depends on a single scale parameter and the given image data. Unlike previous approaches which require careful tuning of the filter kernels for various types of edges, our scheme is general enough to be able to handle different edges, such as lines, step-edges, corners and junctions. Anisotropy in the data is handled automatically by the nonlinear dynamics.

  18. Kinematically complete chemical reaction dynamics

    NASA Astrophysics Data System (ADS)

    Trippel, S.; Stei, M.; Otto, R.; Hlavenka, P.; Mikosch, J.; Eichhorn, C.; Lourderaj, U.; Zhang, J. X.; Hase, W. L.; Weidemüller, M.; Wester, R.

    2009-11-01

    Kinematically complete studies of molecular reactions offer an unprecedented level of insight into the dynamics and the different mechanisms by which chemical reactions occur. We have developed a scheme to study ion-molecule reactions by velocity map imaging at very low collision energies. Results for the elementary nucleophilic substitution (SN2) reaction Cl- + CH3I → ClCH3 + I- are presented and compared to high-level direct dynamics trajectory calculations. Furthermore, an improved design of the crossed-beam imaging spectrometer with full three-dimensional measurement capabilities is discussed and characterization measurements using photoionization of NH3 and photodissociation of CH3I are presented.

  19. On steady kinematic helical dynamos

    NASA Astrophysics Data System (ADS)

    Eltayeb, I. A.; Loper, D. E.

    The equations governing steady kinematic helical dynamos are studied, using the formalism of Benton (1979), when the flow has no radial component (in cylindrical coordinates). It is shown that all solutions must decay exponentially to zero at large distances, s, from the axis of the helix. When the flow depends on s only it is shown that a necessary condition for dynamo action is that the flow possesses components along both the primary and secondary helices. It is also found that periodic motion of one mode along the primary helix cannot support dynamo action even if the field is composed of mean and periodic parts.

  20. Real-time oriented edge detection via difference of shifted image

    NASA Astrophysics Data System (ADS)

    Jeong, Kiseon; Jin, Moonyong; Hwang, Daegyu; Yoon, Sook; Park, Dong Sun

    2013-12-01

    We propose a novel oriented edge detection method called Difference of Shifted Image (DoSI) which has only subtractions between neighborhood pixels using padding-based shifting operation. Firstly, we can more quickly extract an oriented edge component in each direction from 8-neighborhoods using DoSI because there are no multiplications. Then, we can make a final edge map using all edge components by taking maximum value per each pixel. Moreover, we propose various types of oriented edge operators based on the Prewitt, Sobel and Laplacian. They are achieved by combinations of some oriented edge components obtained from DoSI. They have similar performance to existing edge operators based on convolution operations and also their procedures can be implemented in parallel. The experimental results show that the proposed edge detection methods requires less computation time than convolution-based methods and most of them are similar in edge description ability to the existing oriented edge operators.

  1. Edge turbulence in tokamaks

    NASA Astrophysics Data System (ADS)

    Nedospasov, A. V.

    1992-12-01

    Edge turbulence is of decisive importance for the distribution of particle and energy fluxes to the walls of tokamaks. Despite the availability of extensive experimental data on the turbulence properties, its nature still remains a subject for discussion. This paper contains a review of the most recent theoretical and experimental studies in the field, including mainly the studies to which Wootton (A.J. Wooton, J. Nucl. Mater. 176 & 177 (1990) 77) referred to most in his review at PSI-9 and those published later. The available theoretical models of edge turbulence with volume dissipation due to collisions fail to fully interpret the entire combination of experimental facts. In the scrape-off layer of a tokamak the dissipation prevails due to the flow of current through potential shifts near the surface of limiters of divertor plates. The different origins of turbulence at the edge and in the core plasma due to such dissipation are discussed in this paper. Recent data on the electron temperature fluctuations enabled one to evaluate the electric probe measurements of turbulent flows of particles and heat critically. The latest data on the suppression of turbulence in the case of L-H transitions are given. In doing so, the possibility of exciting current instabilities in biasing experiments (rather than only to the suppression of existing turbulence) is given some attention. Possible objectives of further studies are also discussed.

  2. Partnership for Edge Physics Simulation (EPSI)

    SciTech Connect

    Schroder, Peter

    2015-02-11

    We propose to develop advanced simulation codes, based upon an extreme parallelism, first principles kinetic approach, to address the challenges associated with the edge region of magnetically confined plasmas. This work is relevant to both existing magnetic fusion facilities and essential for next-generation burning plasma experiments, such as ITER where success is critically dependent upon H-mode operation achieving an edge pedestal of sufficient height for good core plasma performance without producing deleterious large scale edge localized instabilities. The plasma edge presents a well-known set of multi-physics, multi-scale problems involving complex 3D magnetic geometry. Perhaps the greatest computational challenge is the lack of scale separation – temporal scales for drift waves, Alfven waves, ELM dynamics for example have strong overlap. Similar overlap occurs on the spatial scales for the ion poloidal gyro-radius, drift wave and pedestal width. The traditional approach of separating fusion problems into weakly interacting spatial or temporal domains clearly breaks down in the edge. A full kinetic model (full-f model) must be solved to understand and predict the edge physics including non-equilibrium thermodynamic issues arising from the magnetic topology (the open field lines producing a spatially sensitive velocity hole), plasma wall interactions, neutral and atomic physics. The plan here is to model these phenomena within a comprehensive first principles set of equations without the need for the insurmountable multiple-codes coupling issues by building on the XGC1 code developed under the SciDAC Proto-FSP Center for Plasma Edge Simulation (CPES). This proposal includes the critical participants in the XGC1 development. We propose enhancing the capability of XGC1 by including all the important turbulence physics contained in kinetic ion and electron electromagnetic dynamics, by extending the PIC technology to incorporate several positive features found

  3. Ballistic representation for kinematic access

    NASA Astrophysics Data System (ADS)

    Alfano, Salvatore

    2011-01-01

    This work uses simple two-body orbital dynamics to initially determine the kinematic access for a ballistic vehicle. Primarily this analysis was developed to assess when a rocket body might conjunct with an orbiting satellite platform. A family of access opportunities can be represented as a volume for a specific rocket relative to its launch platform. Alternately, the opportunities can be represented as a geographical footprint relative to aircraft or satellite position that encompasses all possible launcher locations for a specific rocket. A thrusting rocket is treated as a ballistic vehicle that receives all its energy at launch and follows a coasting trajectory. To do so, the rocket's burnout energy is used to find its equivalent initial velocity for a given launcher's altitude. Three kinematic access solutions are then found that account for spherical Earth rotation. One solution finds the maximum range for an ascent-only trajectory while another solution accommodates a descending trajectory. In addition, the ascent engagement for the descending trajectory is used to depict a rapid access scenario. These preliminary solutions are formulated to address ground-, sea-, or air-launched vehicles.

  4. Artefact-reduced kinematics measurement using a geometric finger model with mixture-prior particle filtering.

    PubMed

    Chang, Cheung-Wen; Kuo, Li-Chieh; Jou, I-Ming; Su, Fong-Chin; Sun, Yung-Nien

    2013-01-01

    It is challenging to measure the finger's kinematics of underlying bones in vivo. This paper presents a new method of finger kinematics measurement, using a geometric finger model and several markers deliberately stuck on skin surface. Using a multiple-view camera system, the optimal motion parameters of finger model were estimated using the proposed mixture-prior particle filtering. This prior, consisting of model and marker information, avoids generating improper particles for achieving near real-time performance. This method was validated using a planar fluoroscopy system that worked simultaneously with photographic system. Ten male subjects with asymptomatic hands were investigated in experiments. The results showed that the kinematic parameters could be estimated more accurately by the proposed method than by using only markers. There was 20-40% reduction in skin artefacts achieved for finger flexion/extension. Thus, this profile system can be developed as a tool of reliable kinematics measurement with good applicability for hand rehabilitation.

  5. Wavelet Multiscale Edge Detection Using An ADALINE Neural Network To Match Up Edge Indicators

    DTIC Science & Technology

    2001-12-14

    the WMED is modified to use an ADALINE (ADAptive LInear NEuron) neural network that adapts to match up edge indicators across multiple wavelet levels...The ADALINE uses the least mean squared (LMS) learning rule to minimize the mean square error. The LMS algorithm is able to optimize the decision...boundaries of the network. This makes the boundaries more effective in the presence of noise. This paper will test the capability of the ADALINE to match up the edge indicators in noisy two-dimensional sidescan imagery.

  6. SHIELD: Neutral Gas Kinematics and Dynamics

    NASA Astrophysics Data System (ADS)

    McNichols, Andrew; Teich, Yaron; Cannon, John M.; SHIELD Team

    2016-01-01

    The "Survey of HI in Extremely Low-mass Dwarfs" (SHIELD) is a multiwavelength, legacy-class observational study of 12 low-mass dwarf galaxies discovered in Arecibo Legacy Fast ALFA (ALFALFA) survey data products. Here we present new results of detailed kinematic analyses of these systems using multi-configuration, high spatial (˜300 pc) and spectral (0.82 - 2.46 km s-1 ch-1) resolution HI observations from the Karl G. Jansky Very Large Array. For each source, we produce velocity fields and dispersion maps using different spatial and spectral resolution representations of the data in order to attempt derivation of an inclination-corrected rotation curve. While both two- and three-dimensional fitting techniques are employed, the comparable magnitudes of velocity dispersion and projected rotation result in degeneracies that prohibit unambiguous circular velocity solutions. We thus make multiple position-velocity cuts across each galaxy to determine the maximum circular rotation velocity (≤ 30 km-1 for the survey population). Baryonic masses are calculated using single-dish H I fluxes from Arecibo and stellar masses derived from HST and Spitzer imaging. Comparison is made with total dynamical masses estimated from the position-velocity analysis. The SHIELD galaxies are contextualized on the baryonic Tully-Fisher relation.Support for this work was provided by NSF grant AST-1211683 to JMC at Macalester College.

  7. Dust destruction and kinematics in the Galactic Center

    NASA Technical Reports Server (NTRS)

    Stolovy, Susan R.; Herter, Terry; Gull, George E.; Pirger, Bruce; Vogt, Nicole P.

    1995-01-01

    We present observations of the 34.815 micron (SiII) line and continuum emission from the inner few parsecs of the Galaxy obtained with the KAO Echelle Grating Spectrograph (KEGS) in June 1993. The SiII emission, which has been spectrally resolved at 64 km/s and spatially resolved at 10 arcsec, in kinematically consistent with the motions of ionized and neutral gas interior to the circumnuclear disk (CND). In addition, the emission in the (SiII) line as well as the continuum extends northward along the 'northern arm' past the inner edge of the CND. A peak in the (SiII) line/continuum ratio is observed at approx. 25 arcsec W and 75 arcsec N of Sgr A* with a large velocity dispersion. This may be an indication of dust destruction via cloud-cloud collisions.

  8. Photometric and kinematic studies of extragalactic globular cluster systems

    NASA Astrophysics Data System (ADS)

    Dowell, Jessica

    Globular clusters (GCs) are old, luminous, compact collections of stars found in galaxy halos that formed during the early stages of galaxy formation. Because of this, GCs serve as excellent tracers of the formation, structure, and merger history of their host galaxies. My dissertation will examine both the photometric and kinematic properties of GC systems and their relationship to their host galaxies. In the first section, I will present the analysis of the GC systems of two spiral galaxies, NGC 891 and NGC 1055. I will discuss the photometric methods used to detect GCs using wide-field BVR imaging and to quantify the global properties of the system such as the total number of GCs and their radial distribution. My results for these two GC systems were compared to those of other galaxies. I will also present the results of spectroscopic follow-up for two giant galaxies: the S0 galaxy NGC 4594 (M104), and the elliptical galaxy NGC 3379 (M105). I measured the radial velocities of GCs in these two galaxies, and combined them with published results to determine the mass distribution and mass-to-light (M/L) ratio profile for each galaxy out to large effective radius (7-9 Re). For both galaxies, I found that the M/L profiles increase with radius and do not flatten, which suggests that the dark matter halos in these galaxies extend to the edge of my data. I also looked for evidence of rotation in the GC systems, and found that neither system exhibits significant rotation around the host galaxy. I examined the velocity dispersion profile of each GC system and found kinematic differences between the red and blue GC subpopulations. Finally, I compared my results to mass estimates for these galaxies from other kinematic tracers and considered them in the context of galaxy formation models.

  9. Life on the edge: gastrointestinal parasites from the forest edge and interior primate groups.

    PubMed

    Chapman, Colin A; Speirs, Michaela L; Gillespie, Thomas R; Holland, Timothy; Austad, Kiersten M

    2006-04-01

    Humans are responsible for massive changes to primate habitats, and one unanticipated consequence of these alterations may be changes in host-parasite interactions. Edges are a ubiquitous aspect of human disturbance to forest landscapes. Here we examine how changes associated with the creation of edges in Kibale National Park, Uganda, alter the parasite community that is supported by two species of African colobines: the endangered red colobus (Piliocolobus tephrosceles) and the black-and-white colobus (Colobus guereza). An analysis of 822 fecal samples from edge and forest interior groups revealed no difference in the richness of parasite communities (i.e., the number of parasite species recovered from the host's fecal sample). However, for both species the proportion of individuals with multiple infections was greater in edge than forest interior groups. The prevalence of specific parasites also varied between edge and forest interior groups. Oesophagostomum sp., a potentially deleterious parasite, was 7.4 times more prevalent in red colobus on the edge than in those in the forest interior, and Entamoeba coli was four times more prevalent in red colobus on the edge than in animals from the forest interior. Environmental contamination with parasites (measured as parasite eggs/gm feces) by red colobus from the edge and forest interior differed in a similar fashion to prevalence for red colobus, but it did not differ for black-and-white colobus. For example, egg counts of Oesophagostomum sp. were 10 times higher in red colobus from the edge than in those from the interior. The less severe infections in the black-and-white colobus relative to the red colobus may reflect the fact that black-and-white colobus raid agricultural crops while red colobus do not. This nutritional gain may facilitate a more effective immune response to parasites by the black-and-white colobus. The fact that animals on the edge are likely not nutritionally stressed raises an intriguing

  10. Kinematics and hydrodynamics of linear acceleration in eels, Anguilla rostrata.

    PubMed

    Tytell, Eric D

    2004-12-22

    The kinematics and hydrodynamics of routine linear accelerations were studied in American eels, Anguilla rostrata, using high-speed video and particle image velocimetry. Eels were examined both during steady swimming at speeds from 0.6 to 1.9 body lengths (L) per second and during accelerations from -1.4 to 1.3 L s(-2). Multiple regression of the acceleration and steady swimming speed on the body kinematics suggests that eels primarily change their tail-tip velocity during acceleration. By contrast, the best predictor of steady swimming speed is body wave speed, keeping tail-tip velocity an approximately constant fraction of the swimming velocity. Thus, during steady swimming, Strouhal number does not vary with speed, remaining close to 0.32, but during acceleration, it deviates from the steady value. The kinematic changes during acceleration are indicated hydrodynamically by axial fluid momentum in the wake. During steady swimming, the wake consists of lateral jets of fluid and has minimal net axial momentum, which reflects a balance between thrust and drag. During acceleration, those jets rotate to point downstream, adding axial momentum to the fluid. The amount of added momentum correlates with the acceleration, but is greater than the necessary inertial force by 2.8+/-0.6 times, indicating a substantial acceleration reaction.

  11. pPXF: Penalized Pixel-Fitting stellar kinematics extraction

    NASA Astrophysics Data System (ADS)

    Cappellari, Michele

    2012-10-01

    pPXF is an IDL (and free GDL or FL) program which extracts the stellar kinematics or stellar population from absorption-line spectra of galaxies using the Penalized Pixel-Fitting method (pPXF) developed by Cappellari & Emsellem (2004, PASP, 116, 138). Additional features implemented in the pPXF routine include: Optimal template: Fitted together with the kinematics to minimize template-mismatch errors. Also useful to extract gas kinematics or derive emission-corrected line-strengths indexes. One can use synthetic templates to study the stellar population of galaxies via "Full Spectral Fitting" instead of using traditional line-strengths.Regularization of templates weights: To reduce the noise in the recovery of the stellar population parameters and attach a physical meaning to the output weights assigned to the templates in term of the star formation history (SFH) or metallicity distribution of an individual galaxy.Iterative sigma clipping: To clean the spectra from residual bad pixels or cosmic rays.Additive/multiplicative polynomials: To correct low frequency continuum variations. Also useful for calibration purposes.

  12. The effect of direction on cursor moving kinematics.

    PubMed

    Meng, Ling-Fu; Chen, Hsin-Yung; Lu, Chiu-Ping; Chen, Ming-Chung; Chu, Chi-Nung

    2012-01-01

    There have been only few studies to substantiate the kinematic characteristics of cursor movement. In this study, a quantitative experimental research method was used to explore the effect of moving direction on the kinematics of cursor movement in 24 typical young persons using our previously developed computerized measuring program. The results of multiple one way repeated measures ANOVAs and post hoc LSD tests demonstrated that the moving direction had effects on average velocity, movement time, movement unit and peak velocity. Moving leftward showed better efficiency than moving rightward, upward and downward from the kinematic evidences such as velocity, movement unit and time. Moreover, the unique pattern of the power spectral density (PSD) of velocity (strategy for power application) explained why the smoothness was still maintained while moving leftward even under an unstable situation with larger momentum. Moreover, the information from this cursor moving study can guide us to relocate the toolbars and icons in the window interface, especially for individuals with physical disabilities whose performances are easily interrupted while controlling the cursor in specific directions.

  13. Kinematics and hydrodynamics of linear acceleration in eels, Anguilla rostrata.

    PubMed Central

    Tytell, Eric D.

    2004-01-01

    The kinematics and hydrodynamics of routine linear accelerations were studied in American eels, Anguilla rostrata, using high-speed video and particle image velocimetry. Eels were examined both during steady swimming at speeds from 0.6 to 1.9 body lengths (L) per second and during accelerations from -1.4 to 1.3 L s(-2). Multiple regression of the acceleration and steady swimming speed on the body kinematics suggests that eels primarily change their tail-tip velocity during acceleration. By contrast, the best predictor of steady swimming speed is body wave speed, keeping tail-tip velocity an approximately constant fraction of the swimming velocity. Thus, during steady swimming, Strouhal number does not vary with speed, remaining close to 0.32, but during acceleration, it deviates from the steady value. The kinematic changes during acceleration are indicated hydrodynamically by axial fluid momentum in the wake. During steady swimming, the wake consists of lateral jets of fluid and has minimal net axial momentum, which reflects a balance between thrust and drag. During acceleration, those jets rotate to point downstream, adding axial momentum to the fluid. The amount of added momentum correlates with the acceleration, but is greater than the necessary inertial force by 2.8+/-0.6 times, indicating a substantial acceleration reaction. PMID:15615678

  14. Edge states and skyrmion dynamics in nanostripes of frustrated magnets

    PubMed Central

    Leonov, A. O.; Mostovoy, M.

    2017-01-01

    Magnetic skyrmions are particle-like topological excitations recently discovered in chiral magnets. Their small size, topological protection and the ease with which they can be manipulated by electric currents generated much interest in using skyrmions for information storage and processing. Recently, it was suggested that skyrmions with additional degrees of freedom can exist in magnetically frustrated materials. Here, we show that dynamics of skyrmions and antiskyrmions in nanostripes of frustrated magnets is strongly affected by complex spin states formed at the stripe edges. These states create multiple edge channels which guide the skyrmion motion. Non-trivial topology of edge states gives rise to complex current-induced dynamics, such as emission of skyrmion–antiskyrmion pairs. The edge-state topology can be controlled with an electric current through the exchange of skyrmions and antiskyrmions between the edges of a magnetic nanostructure. PMID:28240226

  15. Investigating Actinide Molecular Adducts From Absorption Edge Spectroscopy

    SciTech Connect

    Den Auwer, C.; Conradson, S.D.; Guilbaud, P.; Moisy, P.; Mustre de Leon, J.; Simoni, E.; /SLAC, SSRL

    2006-10-27

    Although Absorption Edge Spectroscopy has been widely applied to the speciation of actinide elements, specifically at the L{sub III} edge, understanding and interpretation of actinide edge spectra are not complete. In that sense, semi-quantitative analysis is scarce. In this paper, different aspects of edge simulation are presented, including semi-quantitative approaches. Comparison is made between various actinyl (U, Np) aquo or hydroxy compounds. An excursion into transition metal osmium chemistry allows us to compare the structurally related osmyl and uranyl hydroxides. The edge shape and characteristic features are discussed within the multiple scattering picture and the role of the first coordination sphere as well as contributions from the water solvent are described.

  16. Ordered kinematic endpoints for 5-body cascade decays

    NASA Astrophysics Data System (ADS)

    Klimek, Matthew D.

    2016-12-01

    We present expressions for the kinematic endpoints of 5-body cascade decay chains proceeding through all possible combinations of 2-body and 3-body decays, with one stable invisible particle in the final decay stage. When an invariant mass can be formed in multiple ways by choosing different final state particles from a common vertex, we introduce techniques for finding the sub-leading endpoints for all indistinguishable versions of the invariant mass. In contrast to short decay chains, where sub-leading endpoints are linearly related to the leading endpoints, we find that in 5-body decays, they provide additional independent constraints on the mass spectrum.

  17. Kinematic Characterization of Left Ventricular Chamber Stiffness and Relaxation

    NASA Astrophysics Data System (ADS)

    Mossahebi, Sina

    Heart failure is the most common cause of hospitalization today, and diastolic heart failure accounts for 40-50% of cases. Therefore, it is critical to identify diastolic dysfunction at a subclinical stage so that appropriate therapy can be administered before ventricular function is further, and perhaps irreversibly impaired. Basic concepts in physics such as kinematic modeling provide a unique method with which to characterize cardiovascular physiology, specifically diastolic function (DF). The advantage of an approach that is standard in physics, such as the kinematic modeling is its causal formulation that functions in contrast to correlative approaches traditionally utilized in the life sciences. Our research group has pioneered theoretical and experimental quantitative analysis of DF in humans, using both non-invasive (echocardiography, cardiac MRI) and invasive (simultaneous catheterization-echocardiography) methods. Our group developed and validated the Parametrized Diastolic Filling (PDF) formalism which is motivated by basic physiologic principles (LV is a mechanical suction pump at the mitral valve opening) that obey Newton's Laws. PDF formalism is a kinematic model of filling employing an equation of motion, the solution of which accurately predicts all E-wave contours in accordance with the rules of damped harmonic oscillatory motion. The equation's lumped parameters---ventricular stiffness, ventricular viscoelasticity/relaxation and ventricular load---are obtained by solving the 'inverse problem'. The parameters' physiologic significance and clinical utility have been repeatedly demonstrated in multiple clinical settings. In this work we apply our kinematic modeling approach to better understand how the heart works as it fills in order to advance the relationship between physiology and mathematical modeling. Through the use of this modeling, we thereby define and validate novel, causal indexes of diastolic function such as early rapid filling energy

  18. Are shrubland birds edge specialists?

    PubMed

    Schlossberg, Scott; King, David I

    2008-09-01

    In studies of forest fragmentation, birds of scrubby, early-successional habitats are considered edge specialists. Because these birds are assumed to thrive in fragmented, edge-dominated areas, their landscape ecology has received little attention from ecologists. With populations of shrubland birds declining throughout the eastern United States, the question of whether or not these birds really prefer edge habitats has important conservation implications. We used a meta-analysis to test how edges affect the abundance of shrubland birds in early-successional habitats. We analyzed data for 17 species from seven studies that compared the abundances of birds in the interiors and edges of regenerating clearcuts surrounded by mature forest. The meta-analysis clearly showed that shrubland birds avoid edges. All 17 species tested had higher abundances in patch centers than along edges, and edge effects were significant for 8 of 17 species. The key implication of this result is that small or irregular patches, dominated by edge, are unlikely to provide suitable habitat for shrubland birds. Thus, management for these declining species should involve providing large patches and minimizing edges. These findings demonstrate the importance of testing widely accepted ecological classifications and the need to view landscape ecology from the perspective of non-forest wildlife.

  19. 2D CFD Analysis of an Airfoil with Active Continuous Trailing Edge Flap

    NASA Astrophysics Data System (ADS)

    Jaksich, Dylan; Shen, Jinwei

    2014-11-01

    Efficient and quieter helicopter rotors can be achieved through on-blade control devices, such as active Continuous Trailing-Edge Flaps driven by embedded piezoelectric material. This project aims to develop a CFD simulation tool to predict the aerodynamic characteristics of an airfoil with CTEF using open source code: OpenFOAM. Airfoil meshes used by OpenFOAM are obtained with MATLAB scripts. Once created it is possible to rotate the airfoil to various angles of attack. When the airfoil is properly set up various OpenFOAM properties, such as kinematic viscosity and flow velocity, are altered to achieve the desired testing conditions. Upon completion of a simulation, the program gives the lift, drag, and moment coefficients as well as the pressure and velocity around the airfoil. The simulation is then repeated across multiple angles of attack to give full lift and drag curves. The results are then compared to previous test data and other CFD predictions. This research will lead to further work involving quasi-steady 2D simulations incorporating NASTRAN to model aeroelastic deformation and eventually to 3D aeroelastic simulations. NSF ECE Grant #1358991 supported the first author as an REU student.

  20. The discriminant capabilities of stability measures, trunk kinematics, and step kinematics in classifying successful and failed compensatory stepping responses by young adults.

    PubMed

    Crenshaw, Jeremy R; Rosenblatt, Noah J; Hurt, Christopher P; Grabiner, Mark D

    2012-01-03

    This study evaluated the discriminant capability of stability measures, trunk kinematics, and step kinematics to classify successful and failed compensatory stepping responses. In addition, the shared variance between stability measures, step kinematics, and trunk kinematics is reported. The stability measures included the anteroposterior distance (d) between the body center of mass and the stepping limb toe, the margin of stability (MOS), as well as time-to-boundary considering velocity (TTB(v)), velocity and acceleration (TTB(a)), and MOS (TTB(MOS)). Kinematic measures included trunk flexion angle and angular velocity, step length, and the time after disturbance onset of recovery step completion. Fourteen young adults stood on a treadmill that delivered surface accelerations necessitating multiple forward compensatory steps. Thirteen subjects fell from an initial disturbance, but recovered from a second, identical disturbance. Trunk flexion velocity at completion of the first recovery step and trunk flexion angle at completion of the second step had the greatest overall classification of all measures (92.3%). TTB(v) and TTB(a) at completion of both steps had the greatest classification accuracy of all stability measures (80.8%). The length of the first recovery step (r ≤ 0.70) and trunk flexion angle at completion of the second recovery step (r ≤ -0.54) had the largest correlations with stability measures. Although TTB(v) and TTB(a) demonstrated somewhat smaller discriminant capabilities than trunk kinematics, the small correlations between these stability measures and trunk kinematics (|r| ≤ 0.52) suggest that they reflect two important, yet different, aspects of a compensatory stepping response.

  1. Modulation of leading edge vorticity and aerodynamic forces in flexible flapping wings.

    PubMed

    Zhao, Liang; Deng, Xinyan; Sane, Sanjay P

    2011-09-01

    In diverse biological flight systems, the leading edge vortex has been implicated as a flow feature of key importance in the generation of flight forces. Unlike fixed wings, flapping wings can translate at higher angles of attack without stalling because their leading edge vorticity is more stable than the corresponding fixed wing case. Hence, the leading edge vorticity has often been suggested as the primary determinant of the high forces generated by flapping wings. To test this hypothesis, it is necessary to modulate the size and strength of the leading edge vorticity independently of the gross kinematics while simultaneously monitoring the forces generated by the wing. In a recent study, we observed that forces generated by wings with flexible trailing margins showed a direct dependence on the flexural stiffness of the wing. Based on that study, we hypothesized that trailing edge flexion directly influences leading edge vorticity, and thereby the magnitude of aerodynamic forces on the flexible flapping wings. To test this hypothesis, we visualized the flows on wings of varying flexural stiffness using a custom 2D digital particle image velocimetry system, while simultaneously monitoring the magnitude of the aerodynamic forces. Our data show that as flexion decreases, the magnitude of the leading edge vorticity increases and enhances aerodynamic forces, thus confirming that the leading edge vortex is indeed a key feature for aerodynamic force generation in flapping flight. The data shown here thus support the hypothesis that camber influences instantaneous aerodynamic forces through modulation of the leading edge vorticity.

  2. Anisotropic superconductivity driven by kinematic interaction

    NASA Astrophysics Data System (ADS)

    Ivanov, V. A.

    2000-11-01

    We have analysed the effect of kinematic pairing on the symmetry of superconducting order parameter for a square lattice in the frame of the strongly correlated Hubbard model. It is argued that in the first perturbation order the kinematic interaction renormalizes the Hubbard-I dispersions and provides at low doping the mixed singlet (s + s*)-wave superconductivity, giving way at higher doping to the triplet p-wave superconductivity. The obtained phase diagram depends only on the hopping integral parameter. The influence of the Coulomb repulsion on the kinematic superconducting pairing has been estimated. The (s + s*)-wave gap and the thermodynamic critical magnetic field have been derived.

  3. Kinematic determinants of human locomotion.

    PubMed Central

    Borghese, N A; Bianchi, L; Lacquaniti, F

    1996-01-01

    1. The aim of this study was to find kinematic patterns that are invariant across the normal range of locomotion speeds. Subjects walked at different, freely chosen speeds ranging from 0.9 to 2.1 m s-1, while motion and ground reaction forces on the right side of the body were recorded in three-dimensional space. 2. The time course of the anatomical angles of flexion-extension at the hip and ankle was variable not only across subjects, but even from trial to trial in the same subject. By contrast, the time course of the changes in the angles of elevation of each limb segment (pelvis, thigh, shank and foot) relative to the vertical was stereotyped across subjects. 3. To compare the waveforms across speeds, data were scaled in time relative to gait cycle duration. The pattern of ground reaction forces was highly speed dependent. Several distinct families of curves could be recognized in the flexion-extension angles at the hip and ankle. Instead, the waveforms of global length and elevation of the limb, elevation angles of all limb segments and flexion-extension at the knee were invariant with speed. 4. When gait trajectories at all speeds are plotted in the position space defined by the elevation angles of the limb segments, they describe regular loops on a plane. The statistical characteristics of these angular covariations were quantified by means of principal component analysis. The first two principal components accounted together for > 99% of the total experimental variance, and were quantitatively comparable in all subjects. 5. This constraint of planar covariation of the elevation angles is closely reminiscent of that previously described for the control of posture. The existence of laws of intersegmental co-ordination, common to the control of posture and locomotion, presumably assures the maintenance of dynamic equilibrium during forward progression, and the anticipatory adaptation to potentially destabilizing factors by means of co-ordinated kinematic

  4. Edge phonons in black phosphorus

    PubMed Central

    Ribeiro, H. B.; Villegas, C. E. P.; Bahamon, D. A.; Muraca, D.; Castro Neto, A. H.; de Souza, E. A. T.; Rocha, A. R.; Pimenta, M. A.; de Matos, C. J. S.

    2016-01-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements. PMID:27412813

  5. Edge phonons in black phosphorus

    NASA Astrophysics Data System (ADS)

    Ribeiro, H. B.; Villegas, C. E. P.; Bahamon, D. A.; Muraca, D.; Castro Neto, A. H.; de Souza, E. A. T.; Rocha, A. R.; Pimenta, M. A.; de Matos, C. J. S.

    2016-07-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements.

  6. Kinematic dynamo of inertial waves

    NASA Astrophysics Data System (ADS)

    Herreman, Wietze; Le Gal, Patrice; Le Dizes, Stephane

    2008-11-01

    Inertial waves are natural oscillatory tridimensional perturbations in rapidly rotating flows. They can be driven to high amplitudes by an external oscillatory forcing such as precession, or by a parametric instability such as in the elliptical instability. Inertial waves were observed in a MHD-flow (Gans, 1971, JFM ; Kelley et al., 2008, GAFD) and could be responsable of dynamo action. For travelling waves, a constructive alpha-effect was identified (Moffatt, 1970, JFM), but it does not apply to confined inertial wave flows. Yet, recent numerical work demonstrated that precession driven MHD flows can sustain magnetic fields (Tilgner, 2005, POF; Wu & Roberts, 2008, GAFD). This motivates us to study more precisely how inertial waves can exhibit dynamo action. Using a numerical code in cylindrical geometry, we find that standing inertial waves can generate a kinematic dynamo. We show that the dynamo-action results from a second order interaction of the diffusive eigenmodes of the magnetic field with the inertial wave. Scaling laws are obtained, which allows us to to apply the results to flows of geophysical interest.

  7. Milky Way halo gas kinematics

    NASA Technical Reports Server (NTRS)

    Danly, L.

    1986-01-01

    Measurements of high resolution, short wavelength absorption data taken by IUE toward high latitude O and B stars are presented in a discussion of the large scale kinematic properties of Milky Way Halo gas. An analysis of these data demonstrates that: (1) the obsrved absorption widths (FWHM) of Si II are very large, ranging up to 150 Km/s for the most distant halo star; this is much larger than is generally appreciated from optical data; (2) the absorption is observed to be systematically negative in radial velocity, indicating that cool material is, on the whole, flowing toward the disk of the galaxy; (3) there is some evidence for asymmetry between the northern and southern galactic hemispheres, in accordance with the HI 21 cm data toward the galactic poles; (4) low column density gas with highly negative radial LSR velocity (V less than -70 km/s) can be found toward stars beyond 1-3 kpc in the northern galactic hemisphere in all four quadrants of galactic longitude; and (5) only the profiles toward stars in the direction of known high velocity HI features show a clear two component structure.

  8. A kinematic unifying theory of microstructures in subglacial tills

    NASA Astrophysics Data System (ADS)

    Menzies, J.; van der Meer, J. J. M.; Ravier, E.

    2016-10-01

    A key aspect of all subglacial tills is the nature and form of microstructures present. Microstructures are symptomatic of repeated deformation phases prior to, during, and after emplacement. Critical to understanding microstructures in subglacial tills are the probable interrelationship that exists between all of these structures. In analyzing subglacial tills a kinematic deformation relationship can be observed existing between all microstructures. Based upon the rheological conditions at the ice basal interface, a close evolving paleo-strain link can be established that relates levels of deformation to all subglacial till microstructures. As subglacial till undergoes strain during transport and emplacement involving fluctuating conditions of porewater content, percentage of clays present, and changing thermal circumstances, a series of microstructures sequentially evolve. Initially, brittle edge-to-edge grain events occur, followed by grains stack development, often allied closely in time, with microshear formation as the sediment deforms, and is consequently followed by the development of ductile rotation structures. Likewise, deformation bands, shear zone formation, and typically "isolated" domains form. As strain and other factors vary over time so many of these microstructures may be obliterated, altered, or re-oriented. Much remains to be understood regarding paleo-strain conditions and subglacial deformation but a first step has been establishing this temporal sequence of microstructure stage development and thus achieving a theory that unifies these disparate microstructures observed in all subglacial tills.

  9. The Facilitator's Edge: Group Sessions for Edge-ucators.

    ERIC Educational Resources Information Center

    Handcock, Helen

    The Facilitator's Edge is a workshop series based on the life/work messages of The Edge magazine. The workshops are deigned to help educators, youth workers, and their career practitioners facilitate conscious career building. This manual consists of five group sessions, each focusing on a different career-building theme. "Megatrends and…

  10. Giant edge state splitting at atomically precise graphene zigzag edges

    PubMed Central

    Wang, Shiyong; Talirz, Leopold; Pignedoli, Carlo A.; Feng, Xinliang; Müllen, Klaus; Fasel, Roman; Ruffieux, Pascal

    2016-01-01

    Zigzag edges of graphene nanostructures host localized electronic states that are predicted to be spin-polarized. However, these edge states are highly susceptible to edge roughness and interaction with a supporting substrate, complicating the study of their intrinsic electronic and magnetic structure. Here, we focus on atomically precise graphene nanoribbons whose two short zigzag edges host exactly one localized electron each. Using the tip of a scanning tunnelling microscope, the graphene nanoribbons are transferred from the metallic growth substrate onto insulating islands of NaCl in order to decouple their electronic structure from the metal. The absence of charge transfer and hybridization with the substrate is confirmed by scanning tunnelling spectroscopy, which reveals a pair of occupied/unoccupied edge states. Their large energy splitting of 1.9 eV is in accordance with ab initio many-body perturbation theory calculations and reflects the dominant role of electron–electron interactions in these localized states. PMID:27181701

  11. Inverse Kinematics for a Parallel Myoelectric Elbow

    DTIC Science & Technology

    2001-10-25

    Inverse Kinematics for a Parallel Myoelectric Elbow A. Z. Escudero, Ja. Álvarez, L. Leija. Center of Research and Advanced Studies of the IPN...replacement above elbow are serial mechanisms driven by a DC motor and they include only one active articulation for the elbow [1]. Parallel mechanisms...are rather scarce [2]. The inverse kinematics model of a 3-degree of freedom parallel prosthetic elbow mechanism is reported. The mathematical

  12. Wing Leading Edge Debris Analysis

    NASA Technical Reports Server (NTRS)

    Shah, Sandeep; Jerman, Gregory

    2004-01-01

    This is a slide presentation showing the Left Wing Leading Edge (WLE) heat damage observations: Heavy "slag" deposits on select RCC panels. Eroded and knife-edged RCC rib sections. Excessive overheating and slumping of carrier panel tiles. Missing or molten attachment bolts but intact bushing. Deposit mainly on "inside" RCC panel. Deposit on some fractured RCC surface

  13. Rock Segmentation through Edge Regrouping

    NASA Technical Reports Server (NTRS)

    Burl, Michael

    2008-01-01

    Rockster is an algorithm that automatically identifies the locations and boundaries of rocks imaged by the rover hazard cameras (hazcams), navigation cameras (navcams), or panoramic cameras (pancams). The software uses edge detection and edge regrouping to identify closed contours that separate the rocks from the background.

  14. Improved Edge Performance in MRF

    NASA Technical Reports Server (NTRS)

    Shorey, Aric; Jones, Andrew; Durnas, Paul; Tricard, Marc

    2004-01-01

    The fabrication of large segmented optics requires a polishing process that can correct the figure of a surface to within a short distance from its edges-typically, a few millimeters. The work here is to develop QED's Magnetorheological Finishing (MRF) precision polishing process to minimize residual edge effects.

  15. The Robotic Edge Finishing Laboratory

    SciTech Connect

    Loucks, C.S.; Selleck, C.B.

    1990-08-01

    The Robotic Edge Finishing Laboratory at Sandia National Laboratories is developing four areas of technology required for automated deburring, chamfering, and blending of machined edges: (1) the automatic programming of robot trajectories and deburring processes using information derived from a CAD database, (2) the use of machine vision for locating the workpiece coupled with force control to ensure proper tool contact, (3) robotic deburring, blending, and machining of precision chamfered edges, and (4) in-process automated inspection of the formed edge. The Laboratory, its components, integration, and results from edge finishing experiments to date are described here. Also included is a discussion of the issues regarding implementation of the technology in a production environment. 24 refs., 17 figs.

  16. In vivo kinematic evaluation and design considerations related to high flexion in total knee arthroplasty.

    PubMed

    Argenson, Jean-Noël A; Scuderi, Giles R; Komistek, Richard D; Scott, W Norman; Kelly, Michael A; Aubaniac, Jean-Manuel

    2005-02-01

    In designing a posterior-stabilized total knee arthroplasty (TKA) it is preferable that when the cam engages the tibial spine the contact point of the cam move down the tibial spine. This provides greater stability in flexion by creating a greater jump distance and reduces the stress on the tibial spine. In order to eliminate edge loading of the femoral component on the posterior tibial articular surface, the posterior femoral condyles need to be extended. This provides an ideal femoral contact with the tibial articular surface during high flexion angles. To reduce extensor mechanism impingement in deep flexion, the anterior margin of the tibial articular component should be recessed. This provides clearance for the patella and patella tendon. An in vivo kinematic analysis that determined three dimensional motions of the femorotibial joint was performed during a deep knee bend using fluoroscopy for 20 subjects having a TKA designed for deep flexion. The average weight-bearing range-of-motion was 125 degrees . On average, TKA subjects experienced 4.9 degrees of normal axial rotation and all subjects experienced at least -4.4 mm of posterior femoral rollback. It is assumed that femorotibial kinematics can play a major role in patellofemoral kinematics. In this study, subjects implanted with a high-flexion TKA design experienced kinematic patterns that were similar to the normal knee. It can be hypothesized that forces acting on the patella were not substantially increased for TKA subjects compared with the normal subjects.

  17. Butterfly edge effects are predicted by a simple model in a complex landscape.

    PubMed

    Ries, Leslie; Sisk, Thomas D

    2008-05-01

    Edge responses have been studied for decades and form a critical component of our understanding of how organisms respond to landscape structure and habitat fragmentation. Until recently, however, the lack of a general, conceptual framework has made it difficult to make sense of the patterns and variability reported in the edge literature. We present a test of an edge effects model which predicts that organisms should avoid edges with less-preferred habitat, show increased abundance near edges with preferred habitat or habitat containing complementary resources, and show no response to edges with similar-quality habitat that offers only supplementary resources. We tested the predictions of this model against observations of the edge responses of 15 butterfly species at 12 different edge types within a complex, desert riparian landscape. Observations matched model predictions more than would be expected by chance for the 211 species/edge combinations tested over 3 years of study. In cases where positive or negative edge responses were predicted, observed responses matched those predictions 70% of the time. While the model tends to underpredict neutral results, it was rare that an observed edge response contradicted that predicted by the model. This study also supported the two primary ecological mechanisms underlying the model, although not equally. We detected a positive relationship between habitat preferences and the slope of the observed edge response, suggesting that this basic life history trait underlies edge effects and influences their magnitude. Empirical evidence also suggested the presence of complementary resources underlies positive edge responses, but only when completely confined to the adjacent habitat. This multi-species test of a general edge effects model at multiple edge types shows that resource-based mechanisms can explain many edge responses and that a modest knowledge of life history attributes and resource availability is sufficient for

  18. Edge-on Galaxy

    NASA Technical Reports Server (NTRS)

    1999-01-01

    NASA's Hubble Space Telescope has imaged an unusual edge-on galaxy, revealing remarkable details of its warped dusty disc and showing how colliding galaxies trigger the birth of new stars.

    The image, taken by Hubble's Wide Field and Planetary Camera 2 (WFPC2), is online at http://heritage.stsci.edu and http://www.jpl.nasa.gov/images/wfpc. The camera was designed and built by NASA's Jet Propulsion Laboratory, Pasadena, Calif. During observations of the galaxy, the camera passed a milestone, taking its 100,000th image since shuttle astronauts installed it in Hubble in 1993.

    The dust and spiral arms of normal spiral galaxies, like our Milky Way, look flat when seen edge- on. The new image of the galaxy ESO 510-G13 shows an unusual twisted disc structure, first seen in ground-based photographs taken at the European Southern Observatory in Chile. ESO 510-G13 lies in the southern constellation Hydra, some 150 million light-years from Earth. Details of the galaxy's structure are visible because interstellar dust clouds that trace its disc are silhouetted from behind by light from the galaxy's bright, smooth central bulge.

    The strong warping of the disc indicates that ESO 510-G13 has recently collided with a nearby galaxy and is in the process of swallowing it. Gravitational forces distort galaxies as their stars, gas, and dust merge over millions of years. When the disturbances die out, ESO 510-G13 will be a single galaxy.

    The galaxy's outer regions, especially on the right side of the image, show dark dust and bright clouds of blue stars. This indicates that hot, young stars are forming in the twisted disc. Astronomers believe star formation may be triggered when galaxies collide and their interstellar clouds are compressed.

    The Hubble Heritage Team used WFPC2 to observe ESO 510-G13 in April 2001. Pictures obtained through blue, green, and red filters were combined to make this color-composite image, which emphasizes the contrast between the dusty

  19. Measuring wing kinematics, flight trajectory and body attitude during forward flight and turning maneuvers in dragonflies.

    PubMed

    Wang, Hao; Zeng, Lijiang; Liu, Hao; Yin, Chunyong

    2003-02-01

    A robust technique for determining the wing kinematics, body position and attitude of a free-flight dragonfly is described. The new method is based on a projected comb-fringe technique combined with the natural landmarks on a dragonfly, allowing us to establish the local body-centered coordinate system with high accuracy, and to measure the body attitude at any instant. The kinematic parameters, including wingbeat frequency, flapping angle, angle of attack, torsional angle and camber deformation, required no assumptions to be made with respect to wing geometry, deformability (except the assumption of rigid leading edges) or bilateral wing symmetry. Two typical flight behaviors, forward flight and turning maneuvers, of dragonflies Polycanthagyna melanictera Selys were measured and analyzed.

  20. Kinematics of the SgrB2(N-LMH) Molecular Core

    NASA Technical Reports Server (NTRS)

    Hollis, J. M.; Pedelty, J. A.; Boboltz, D. A.; Liu, S.-Y.; Snyder, L. E.; Palmer, Patrick; Lovas, F. J.; Jewell, P. R.

    2003-01-01

    Ethyl cyanide (CH3CH2CN) emission and absorption have been imaged with the Very Large Array (VLA) toward SgrB2(N-LMH) by means of the 5(sub 15)-4(sub 14) rotational transition at 43.5 GHz (lambda approx. 7 mm). The 1.5" x 1.4" VLA beam shows two principal sources of ethyl cyanide emission: an unresolved source approx. 5" north of the LMH that is kinematically consistent with simple expansion, contraction, or small-scale turbulence, and the resolved LMH core source itself that shows kinematics indicating an edge-on rotating disk that extends 23" (approx. 0.1 pc) in the approximate east-west direction. A search for the 7(sub 07)-6(sub 06) rotational transition of the amino acid glycine (NH2CH2COOH) at 43.7 GHz toward SgrB2(N-LMH) gave negative results.

  1. Red edge measurements for remotely sensing plant chlorophyll content

    NASA Technical Reports Server (NTRS)

    Horler, D. N. H.; Dockray, M.; Barber, J.; Barringer, A. R.

    1983-01-01

    The feasibility of using the wavelength of the maximum slope of the red edge of leaf reflectance spectra, Lambda(re), as an indication of plant chlorophyll status was examined in the laboratory for single leaves of several species. Lambda(re) for each sample was determined by derivative reflectance spectroscopy. A high positive correlation was found between Lambda(re) and leaf chlorophyll content for all species, although there were some differences in the quantitative nature of the relationship for plants of different types. The position of the red edge was found to be unaffected by simulated change in ground cover, but multiple leaf layers produced a shift in its position. Appropriate spectral measurements and processing for obtaining useful information from the red edge are discussed, and the potential of the red edge in relation to other spectral measurements is considered.

  2. Kinematic parameters that influence the aesthetic perception of beauty in contemporary dance.

    PubMed

    Torrents, Carlota; Castañer, Marta; Jofre, Toni; Morey, Gaspar; Reverter, Ferran

    2013-01-01

    Some experiments have stablished that certain kinematic parameters can influence the subjective aesthetic perception of the dance audience. Neave, McCarty, Freynik, Caplan, Hönekopp, and Fink (2010, Biology Letters 7 221-224) reported eleven movement parameters in non-expert male dancers, showing a significant positive correlation with perceived dance quality. We aim to identify some of the kinematic parameters of expert dancers' movements that influence the subjective aesthetic perception of observers in relation to specific skills of contemporary dance. Four experienced contemporary dancers performed three repetitions of four dance-related motor skills. Motion was captured by a VICON-MX system. The resulting 48 animations were viewed by 108 observers. The observers judged beauty using a semantic differential. The data were then subjected to multiple factor analysis. The results suggested that there were strong associations between higher beauty scores and certain kinematic parameters, especially those related to amplitude of movement.

  3. Incremental inverse kinematics based vision servo for autonomous robotic capture of non-cooperative space debris

    NASA Astrophysics Data System (ADS)

    Dong, Gangqi; Zhu, Z. H.

    2016-04-01

    This paper proposed a new incremental inverse kinematics based vision servo approach for robotic manipulators to capture a non-cooperative target autonomously. The target's pose and motion are estimated by a vision system using integrated photogrammetry and EKF algorithm. Based on the estimated pose and motion of the target, the instantaneous desired position of the end-effector is predicted by inverse kinematics and the robotic manipulator is moved incrementally from its current configuration subject to the joint speed limits. This approach effectively eliminates the multiple solutions in the inverse kinematics and increases the robustness of the control algorithm. The proposed approach is validated by a hardware-in-the-loop simulation, where the pose and motion of the non-cooperative target is estimated by a real vision system. The simulation results demonstrate the effectiveness and robustness of the proposed estimation approach for the target and the incremental control strategy for the robotic manipulator.

  4. KINEMATIC AND SPATIAL SUBSTRUCTURE IN NGC 2264

    SciTech Connect

    Tobin, John J.; Hartmann, Lee; Hsu, Wen-Hsin; Mateo, Mario; Fűrész, Gabor

    2015-04-15

    We present an expanded kinematic study of the young cluster NGC 2264 based upon optical radial velocities measured using multi-fiber echelle spectroscopy at the 6.5 m MMT and Magellan telescopes. We report radial velocities for 695 stars, of which approximately 407 stars are confirmed or very likely members. Our results more than double the number of members with radial velocities from Fűrész et al., resulting in a much better defined kinematic relationship between the stellar population and the associated molecular gas. In particular, we find that there is a significant subset of stars that are systematically blueshifted with respect to the molecular ({sup 13}CO) gas. The detection of Lithium absorption and/or infrared excesses in this blueshifted population suggests that at least some of these stars are cluster members; we suggest some speculative scenarios to explain their kinematics. Our results also more clearly define the redshifted population of stars in the northern end of the cluster; we suggest that the stellar and gas kinematics of this region are the result of a bubble driven by the wind from O7 star S Mon. Our results emphasize the complexity of the spatial and kinematic structure of NGC 2264, important for eventually building up a comprehensive picture of cluster formation.

  5. The fish tail motion forms an attached leading edge vortex.

    PubMed

    Borazjani, Iman; Daghooghi, Mohsen

    2013-04-07

    The tail (caudal fin) is one of the most prominent characteristics of fishes, and the analysis of the flow pattern it creates is fundamental to understanding how its motion generates locomotor forces. A mechanism that is known to greatly enhance locomotor forces in insect and bird flight is the leading edge vortex (LEV) reattachment, i.e. a vortex (separation bubble) that stays attached at the leading edge of a wing. However, this mechanism has not been reported in fish-like swimming probably owing to the overemphasis on the trailing wake, and the fact that the flow does not separate along the body of undulating swimmers. We provide, to our knowledge, the first evidence of the vortex reattachment at the leading edge of the fish tail using three-dimensional high-resolution numerical simulations of self-propelled virtual swimmers with different tail shapes. We show that at Strouhal numbers (a measure of lateral velocity to the axial velocity) at which most fish swim in nature (approx. 0.25) an attached LEV is formed, whereas at a higher Strouhal number of approximately 0.6 the LEV does not reattach. We show that the evolution of the LEV drastically alters the pressure distribution on the tail and the force it generates. We also show that the tail's delta shape is not necessary for the LEV reattachment and fish-like kinematics is capable of stabilising the LEV. Our results suggest the need for a paradigm shift in fish-like swimming research to turn the focus from the trailing edge to the leading edge of the tail.

  6. Hummingbirds control turning velocity using body orientation and turning radius using asymmetrical wingbeat kinematics

    PubMed Central

    Read, Tyson J. G.; Segre, Paolo S.; Middleton, Kevin M.; Altshuler, Douglas L.

    2016-01-01

    Turning in flight requires reorientation of force, which birds, bats and insects accomplish either by shifting body position and total force in concert or by using left–right asymmetries in wingbeat kinematics. Although both mechanisms have been observed in multiple species, it is currently unknown how each is used to control changes in trajectory. We addressed this problem by measuring body and wingbeat kinematics as hummingbirds tracked a revolving feeder, and estimating aerodynamic forces using a quasi-steady model. During arcing turns, hummingbirds symmetrically banked the stroke plane of both wings, and the body, into turns, supporting a body-dependent mechanism. However, several wingbeat asymmetries were present during turning, including a higher and flatter outer wingtip path and a lower more deviated inner wingtip path. A quasi-steady analysis of arcing turns performed with different trajectories revealed that changes in radius were associated with asymmetrical kinematics and forces, and changes in velocity were associated with symmetrical kinematics and forces. Collectively, our results indicate that both body-dependent and -independent force orientation mechanisms are available to hummingbirds, and that these kinematic strategies are used to meet the separate aerodynamic challenges posed by changes in velocity and turning radius. PMID:27030042

  7. Solution of Inverse Kinematics for 6R Robot Manipulators With Offset Wrist Based on Geometric Algebra.

    PubMed

    Fu, Zhongtao; Yang, Wenyu; Yang, Zhen

    2013-08-01

    In this paper, we present an efficient method based on geometric algebra for computing the solutions to the inverse kinematics problem (IKP) of the 6R robot manipulators with offset wrist. Due to the fact that there exist some difficulties to solve the inverse kinematics problem when the kinematics equations are complex, highly nonlinear, coupled and multiple solutions in terms of these robot manipulators stated mathematically, we apply the theory of Geometric Algebra to the kinematic modeling of 6R robot manipulators simply and generate closed-form kinematics equations, reformulate the problem as a generalized eigenvalue problem with symbolic elimination technique, and then yield 16 solutions. Finally, a spray painting robot, which conforms to the type of robot manipulators, is used as an example of implementation for the effectiveness and real-time of this method. The experimental results show that this method has a large advantage over the classical methods on geometric intuition, computation and real-time, and can be directly extended to all serial robot manipulators and completely automatized, which provides a new tool on the analysis and application of general robot manipulators.

  8. A Kinematic Calibration Process for Flight Robotic Arms

    NASA Technical Reports Server (NTRS)

    Collins, Curtis L.; Robinson, Matthew L.

    2013-01-01

    The Mars Science Laboratory (MSL) robotic arm is ten times more massive than any Mars robotic arm before it, yet with similar accuracy and repeatability positioning requirements. In order to assess and validate these requirements, a higher-fidelity model and calibration processes were needed. Kinematic calibration of robotic arms is a common and necessary process to ensure good positioning performance. Most methodologies assume a rigid arm, high-accuracy data collection, and some kind of optimization of kinematic parameters. A new detailed kinematic and deflection model of the MSL robotic arm was formulated in the design phase and used to update the initial positioning and orientation accuracy and repeatability requirements. This model included a higher-fidelity link stiffness matrix representation, as well as a link level thermal expansion model. In addition, it included an actuator backlash model. Analytical results highlighted the sensitivity of the arm accuracy to its joint initialization methodology. Because of this, a new technique for initializing the arm joint encoders through hardstop calibration was developed. This involved selecting arm configurations to use in Earth-based hardstop calibration that had corresponding configurations on Mars with the same joint torque to ensure repeatability in the different gravity environment. The process used to collect calibration data for the arm included the use of multiple weight stand-in turrets with enough metrology targets to reconstruct the full six-degree-of-freedom location of the rover and tool frames. The follow-on data processing of the metrology data utilized a standard differential formulation and linear parameter optimization technique.

  9. Kinematic Origins of Motor Inconsistency in Expert Pianists

    PubMed Central

    Tominaga, Kenta; Lee, André; Altenmüller, Eckart; Miyazaki, Fumio

    2016-01-01

    For top performers, including athletes and musicians, even subtle inconsistencies in rhythm and force during movement production decrease the quality of performance. However, extensive training over many years beginning in childhood is unable to perfect dexterous motor performance so that it is without any error. To gain insight into the biological mechanisms underlying the subtle defects of motor actions, the present study sought to identify the kinematic origins of inconsistency of dexterous finger movements in musical performance. Seven highly-skilled pianists who have won prizes at international piano competitions played a short sequence of tones with the right hand at a predetermined tempo. Time-varying joint angles of the fingers were recorded using a custom-made data glove, and the timing and velocity of the individual keystrokes were recorded from a digital piano. Both ridge and stepwise multiple regression analyses demonstrated an association of the inter-trial variability of the inter-keystroke interval (i.e., rhythmic inconsistency) with both the rotational velocity of joints of the finger used for a keystroke (i.e., striking finger) and the movement independence between the striking and non-striking fingers. This indicates a relationship between rhythmic inconsistency in musical performance and the dynamic features of movements in not only the striking finger but also the non-striking fingers. In contrast, the inter-trial variability of the key-descending velocity (i.e., loudness inconsistency) was associated mostly with the kinematic features of the striking finger at the moment of the keystroke. Furthermore, there was no correlation between the rhythmic and loudness inconsistencies. The results suggest distinct kinematic origins of inconsistencies in rhythm and loudness in expert musical performance. PMID:27537686

  10. Kinematic and dynamic analysis of an anatomically based knee joint.

    PubMed

    Lee, Kok-Meng; Guo, Jiajie

    2010-05-07

    This paper presents a knee-joint model to provide a better understanding on the interaction between natural joints and artificial mechanisms for design and control of rehabilitation exoskeletons. The anatomically based knee model relaxes several commonly made assumptions that approximate a human knee as engineering pin-joint in exoskeleton design. Based on published MRI data, we formulate the kinematics of a knee-joint and compare three mathematical approximations; one model bases on two sequential circles rolling a flat plane; and the other two are mathematically differentiable ellipses-based models with and without sliding at the contact. The ellipses-based model taking sliding contact into accounts shows that the rolling-sliding ratio of a knee-joint is not a constant but has an average value consistent with published measurements. This knee-joint kinematics leads to a physically more accurate contact-point trajectory than methods based on multiple circles or lines, and provides a basis to derive a knee-joint kinetic model upon which the effects of a planar exoskeleton mechanism on the internal joint forces and torque during flexion can be numerically investigated. Two different knee-joint kinetic models (pin-joint approximation and anatomically based model) are compared against a condition with no exoskeleton. The leg and exoskeleton form a closed kinematic chain that has a significant effect on the joint forces in the knee. Human knee is more tolerant than pin-joint in negotiating around a singularity but its internal forces increase with the exoskeleton mass-to-length ratio. An oversimplifying pin-joint approximation cannot capture the finite change in the knee forces due to the singularity effect.

  11. Generic robotic kinematic generator for virtual environment interfaces

    NASA Astrophysics Data System (ADS)

    Flueckiger, Lorenzo; Piguet, Laurent; Baur, Charles

    1996-12-01

    The expansion of robotic systems' performance, as well as the need for such machines to work in complex environments (hazardous, small, distant, etc.), involves the need for user interfaces which permit efficient teleoperation. Virtual Reality based interfaces provide the user with a new method for robot task planning and control: he or she can define tasks in a very intuitive way by interacting with a 3D computer generated representation of the world, which is continuously updated thanks to multiple sensors fusion and analysis. The Swiss Federal Institute of Technology has successfully tested different kinds of teleoperations. In the early 90s, a transatlantic teleoperation of a conventional robot manipulator with a vision feedback system to update the virtual world was achieved. This approach was then extended to perform teleoperation of several mobile robots (Khepera, Koala) as well as to control microrobots used for microsystems' assembly in the micrometer range. One of the problems encountered with such an approach is the necessity to program a specific kinematic algorithm for each kind of manipulator. To provide a more general solution, we started a project aiming at the design of a 'kinematic generator' (CINEGEN) for the simulation of generic serial and parallel mechanical chains. With CINEGEN, each manipulator is defined with an ascii file description and its attached graphics files; inserting a new manipulator simply requires a new description file, and none of the existing tools require modification. To have a real time behavior, we have chosen a numerical method based on the pseudo-Jacobian method to generate the inverse kinematics of the robot. The results obtained with an object-oriented implementation on a graphic workstation are presented in this paper.

  12. Kinematic Origins of Motor Inconsistency in Expert Pianists.

    PubMed

    Tominaga, Kenta; Lee, André; Altenmüller, Eckart; Miyazaki, Fumio; Furuya, Shinichi

    2016-01-01

    For top performers, including athletes and musicians, even subtle inconsistencies in rhythm and force during movement production decrease the quality of performance. However, extensive training over many years beginning in childhood is unable to perfect dexterous motor performance so that it is without any error. To gain insight into the biological mechanisms underlying the subtle defects of motor actions, the present study sought to identify the kinematic origins of inconsistency of dexterous finger movements in musical performance. Seven highly-skilled pianists who have won prizes at international piano competitions played a short sequence of tones with the right hand at a predetermined tempo. Time-varying joint angles of the fingers were recorded using a custom-made data glove, and the timing and velocity of the individual keystrokes were recorded from a digital piano. Both ridge and stepwise multiple regression analyses demonstrated an association of the inter-trial variability of the inter-keystroke interval (i.e., rhythmic inconsistency) with both the rotational velocity of joints of the finger used for a keystroke (i.e., striking finger) and the movement independence between the striking and non-striking fingers. This indicates a relationship between rhythmic inconsistency in musical performance and the dynamic features of movements in not only the striking finger but also the non-striking fingers. In contrast, the inter-trial variability of the key-descending velocity (i.e., loudness inconsistency) was associated mostly with the kinematic features of the striking finger at the moment of the keystroke. Furthermore, there was no correlation between the rhythmic and loudness inconsistencies. The results suggest distinct kinematic origins of inconsistencies in rhythm and loudness in expert musical performance.

  13. Highly damped kinematic coupling for precision instruments

    DOEpatents

    Hale, Layton C.; Jensen, Steven A.

    2001-01-01

    A highly damped kinematic coupling for precision instruments. The kinematic coupling provides support while causing essentially no influence to its nature shape, with such influences coming, for example, from manufacturing tolerances, temperature changes, or ground motion. The coupling uses three ball-cone constraints, each combined with a released flexural degree of freedom. This arrangement enables a gain of higher load capacity and stiffness, but can also significantly reduce the friction level in proportion to the ball radius divided by the distance between the ball and the hinge axis. The blade flexures reduces somewhat the stiffness of the coupling and provides an ideal location to apply constrained-layer damping which is accomplished by attaching a viscoelastic layer and a constraining layer on opposite sides of each of the blade flexures. The three identical ball-cone flexures provide a damped coupling mechanism to kinematically support the projection optics system of the extreme ultraviolet lithography (EUVL) system, or other load-sensitive apparatus.

  14. Kinematics of the Most Efficient Cilium

    NASA Astrophysics Data System (ADS)

    Eloy, Christophe; Lauga, Eric

    2012-07-01

    In a variety of biological processes, eukaryotic cells use cilia to transport flow. Although cilia have a remarkably conserved internal molecular structure, experimental observations report very diverse kinematics. To address this diversity, we determine numerically the kinematics and energetics of the most efficient cilium. Specifically, we compute the time-periodic deformation of a wall-bound elastic filament leading to transport of a surrounding fluid at minimum energetic cost, where the cost is taken to be the positive work done by all internal molecular motors. The optimal kinematics are found to strongly depend on the cilium bending rigidity through a single dimensionless number, the Sperm number, and closely resemble the two-stroke ciliary beating pattern observed experimentally.

  15. Optimal pumping kinematics of a cilium

    NASA Astrophysics Data System (ADS)

    Eloy, Christophe; Lauga, Eric

    2012-11-01

    In a variety of biological processes, eukaryotic cells use cilia to transport flow. Although the internal molecular structure of cilia has been remarkably conserved throughout evolution, experimental observations report qualitatively diverse kinematics in different species. To address this diversity, we have determined numerically the kinematics of the most efficient cilium. Specifically, we have computed the time-periodic deformation of a wall-bound elastic filament leading to transport of a surrounding fluid at minimum energetic cost. Here, the energetic cost is taken to be the sum of positive works done by the internal torques, such that elastic energy is not conservative. The optimal kinematics are found to strongly depend on the cilium bending rigidity through a single dimensionless number, the Sperm number Sp, and closely resemble the two-stroke ciliary beating pattern observed experimentally. We acknowledge supports from the EU (fellowship PIOF-GA-2009-252542 to C.E.) and the NSF (grant CBET-0746285 to E.L.).

  16. Kinematic analysis of 7-DOF manipulators

    NASA Technical Reports Server (NTRS)

    Kreutz-Delgado, Kenneth; Long, Mark; Seraji, Homayoun

    1992-01-01

    This article presents a kinematic analysis of seven-degree-of-freedom serial link spatial manipulators with revolute joints. To uniquely determine the joint angles for a given end-effector position and orientation, the redundancy is parameterized by a scalar variable that defines the angle between the arm plane and a reference plane. The forward kinematic mappings from joint space to end-effector coordinates and arm angle and the augmented Jacobian matrix that gives end-effector and arm angle rates as functions of joint rates are presented. Conditions under which the augmented Jacobian becomes singular are also given and are shown to correspond to the arm being either at a kinematically singular configuration or at a nonsingular configuration for which the arm angle ceases to parameterize the redundancy.

  17. Kinematic analysis of 7 DOF anthropomorphic arms

    NASA Technical Reports Server (NTRS)

    Kreutz-Delgado, K.; Long, M.; Seraji, H.

    1990-01-01

    A kinematic analysis of anthropomorphic seven-degree-of-freedom serial link spatial manipulators with revolute joints is presented. To uniquely determine joint angles for a given end-effector position and orientation, the redundancy is parameterized by a scalar variable which corresponds to the angle between the arm plane and a reference plane. The forward kinematic mappings from joint-space to end-effector coordinates and arm angle and the augmented Jacobian matrix which gives end-effector and arm angle rates as functions of joint rates are given. Conditions under which the augmented Jacobian becomes singular are given and are shown to correspond to the arm being either at a kinematically singular configuration or at a nonsingular configuration for which the arm angle ceases to parameterize the redundancy.

  18. Gas Kinematics in the Multiphase Circumgalactic Medium

    NASA Astrophysics Data System (ADS)

    Nielsen, Nikole M.; Kacprzak, Glenn G.; Churchill, Christopher W.; Murphy, Michael T.; Muzahid, Sowgat; Charlton, Jane C.; Evans, Jessica L.

    2017-03-01

    We use high-resolution Keck, VLT, or Hubble Space Telescope spectra of background quasars to examine the kinematic properties of the multiphase, metal-enriched circumgalactic medium in the outskirts of galaxies at 0.08 < z gal < 1.0, focusing on the low-ionization Mgii and high-ionization Ovi doublets. The absorption kinematics of low-ionization gas in the circumgalactic medium depend strongly on the star formation activity and the location about the host galaxy, where the largest velocity dispersions are associated with blue, face-on galaxies probed along the minor axis. Conversely, high-ionization gas kinematics are independent of galaxy star formation activity and orientation.

  19. Edge equilibrium code for tokamaks

    SciTech Connect

    Li, Xujing; Drozdov, Vladimir V.

    2014-01-15

    The edge equilibrium code (EEC) described in this paper is developed for simulations of the near edge plasma using the finite element method. It solves the Grad-Shafranov equation in toroidal coordinate and uses adaptive grids aligned with magnetic field lines. Hermite finite elements are chosen for the numerical scheme. A fast Newton scheme which is the same as implemented in the equilibrium and stability code (ESC) is applied here to adjust the grids.

  20. A kinematic study of Tycho's supernova remnant

    NASA Astrophysics Data System (ADS)

    Hughes, P. J.; Sato, T.

    2016-06-01

    Thanks to its confirmed nature as the remnant of a standard Type Ia supernova from spectroscopy of its light echo, Tycho's supernova remnant is a unique object that can provide a new perspective into thermonuclear supernova explosions. More than 400 years after its discovery as a supernova in November 1572, the remnant is now spread out over an 8 arcminute diameter region in a fairly symmetric, but patchy, shell-like morphology. The remnant's thermal X-ray emission is dominated by a strong Si Kalpha line and also shows line emission from other species such as S, Ar, Ca, and Fe. Existing proper motion and X-ray line width measurements indicate that Tycho's Si-rich ejecta shell is expanding at ~4700 km/s. We have taken advantage of the huge number of Si line photons in the 750-ks Chandra ACIS observation from 2009 to make the first direct velocity measurements of ejecta in Tycho. The patchy nature of the ejecta shell allows for identification of red- and blue-shifted clumps of emission from the receding and approaching hemispheres. We use nonequilibrium ionization thermal models to jointly fit both ACIS-S and ACIS-I observations to determine the radial expansion velocity of individual clumps and associated systematic uncertainty. Red-shifted clumps have speeds of 3500-7800 km/s and blue-shifted clumps 1600--5000 km/s with a systematic uncertainty of 500-2000 km/s determined by intercomparison of the ACIS-S and ACIS-I spectral results. From our Chandra radial analysis of surface brightness, centroid energy, and line width, we have confirmed previous line width measurements from Suzaku, but are able to utilize finer radial bins that reveal additional structure in the kinematics of Tycho. In particular the Si and S line widths reach a deep minimum at the position of the peak surface brightness near the remnant's edge and where Doppler broadening from the shell expansion is minimum. From the measured line widths and assuming that Doppler and turbulent broadening can be

  1. SMACK - SMOOTHING FOR AIRCRAFT KINEMATICS

    NASA Technical Reports Server (NTRS)

    Bach, R.

    1994-01-01

    The computer program SMACK (SMoothing for AirCraft Kinematics) is designed to provide flightpath reconstruction of aircraft forces and motions from measurements that are noisy or incomplete. Additionally, SMACK provides a check on instrument accuracy and data consistency. The program can be used to analyze data from flight-test experiments prior to their use in performance, stability and control, or aerodynamic modeling calculations. It can also be used in the analysis of aircraft accidents, where the actual forces and motions may have to be determined from a very limited data set. Application of a state-estimation method for flightpath reconstruction is possible because aircraft forces and motions are related by well-known equations of motion. The task of postflight state estimation is known as a nonlinear, fixed-interval smoothing problem. SMACK utilizes a backward-filter, forward-smoother algorithm to solve the problem. The equations of motion are used to produce estimates that are compared with their corresponding measurement time histories. The procedure is iterative, providing improved state estimates until a minimum squared-error measure is achieved. In the SMACK program, the state and measurement models together represent a finite-difference approximation for the six-degree-of-freedom dynamics of a rigid body. The models are used to generate time histories which are likely to be found in a flight-test measurement set. These include onboard variables such as Euler angles, angular rates, and linear accelerations as well as tracking variables such as slant range, bearing, and elevation. Any bias or scale-factor errors associated with the state or measurement models are appended to the state vector and treated as constant but unknown parameters. The SMACK documentation covers the derivation of the solution algorithm, describes the state and measurement models, and presents several application examples that should help the analyst recognize the potential

  2. Graph Theory Roots of Spatial Operators for Kinematics and Dynamics

    NASA Technical Reports Server (NTRS)

    Jain, Abhinandan

    2011-01-01

    bodies, the indexing schemes, etc. The relationship of the underlying structure is intimately connected with efficient, recursive computational algorithms. The results provide the foundational groundwork for a much broader look at the key problems in kinematics and dynamics. The properties of general graphs and trees of nodes and edge were examined, as well as the properties of adjacency matrices that are used to describe graph connectivity. The nilpotency property of such matrices for directed trees was reviewed, and the adjacency matrices were generalized to the notion of block weighted adjacency matrices that support block matrix elements. This leads us to the development of the notion of Spatial Kernel Operator SKO kernels. These kernels provide the basis for the development of SKO resolvent operators.

  3. Photometric and Kinematic Studies of Extragalactic Globular Cluster Systems

    NASA Astrophysics Data System (ADS)

    Windschitl-Dowell, Jessica L.

    2015-01-01

    Globular clusters (GCs) are compact, luminous collections of stars created during the early stages of galaxy formation. As a result, the properties of GC systems provide important clues about the formation, merger history, and structure of their host galaxies. In particular, kinematic studies of GCs can be used to investigate the dark matter distribution in galaxy halos and provide observational evidence that can be used to constrain models of galaxy formation. I will present our study of the GC systems of two spiral galaxies, NGC 891 and NGC 1055, and show how we used wide-field BVR imaging from the WIYN 3.5-m telescope to detect the GC population and measure the global properties of the system. We quantified the radial distribution of the GC system and total number of GCs in these galaxies and compared the results to those of other galaxies.I will also present the results of spectroscopic follow-up for two giant galaxies: the S0 galaxy NGC 4594 (M104), and the elliptical galaxy NGC 3379 (M105). Using spectra taken with AAT/AAOmega, WIYN/HYDRA, and MMT/Hectospec, I measured the radial velocities of GCs, and combined them with published results to determine the mass distribution and V-band mass-to-light (M/LV) ratio profile for each galaxy out to large effective radius (7-9 Re). I compared our results to mass estimates from other kinematic tracers and also considered them in the context of galaxy formation models. For both galaxies, I found that the M/LV profiles increase with radius and do not flatten, which suggests that the dark matter halos in these galaxies extend to the edge of our data. I also looked for evidence of rotation within the GC systems, and found that neither system exhibits significant rotation around the host galaxy. Finally, I examined the velocity dispersion of each GC system as a function of radius and found kinematic differences between the red, metal-rich and blue, metal-poor GC subpopulations.

  4. Resilience of southwestern Amazon forests to anthropogenic edge effects.

    PubMed

    Phillips, Oliver L; Rose, Sam; Mendoza, Abel Monteagudo; Vargas, Percy Núñez

    2006-12-01

    Anthropogenic edge effects can compromise the conservation value of mature tropical forests. To date most edge-effect research in Amazonia has concentrated on forests in relatively seasonal locations or with poor soils in the east of the basin. We present the first evaluation from the relatively richer soils of far western Amazonia on the extent to which mature forest biomass, diversity, and composition are affected by edges. In a southwestern Amazonian landscape we surveyed woody plant diversity, species composition, and biomass in 88x0.1 ha samples of unflooded forest that spanned a wide range in soil properties and included samples as close as 50 m and as distant as >10 km from anthropogenic edges. We applied Mantel tests, multiple regression on distance matrices, and other multivariate techniques to identify anthropogenic effects before and after accounting for soil factors and spatial autocorrelation. The distance to the nearest edge, access point, and the geographical center of the nearest community ("anthropogenic-distance effects") all had no detectable effect on tree biomass or species diversity. Anthropogenic-distance effects on tree species composition were also below the limits of detection and were negligible in comparison with natural environmental and spatial factors. Analysis of the data set's capacity to detect anthropogenic effects confirmed that the forests were not severely affected by edges, although because our study had few plots within 100 m of forest edges, our confidence in patterns in the immediate vicinity of edges is limited. It therefore appears that the conservation value of most "edge" forests in this region has not yet been compromised substantially. We caution that because this is one case study it should not be overinterpreted, but one explanation for our findings may be that western Amazonian tree species are naturally faster growing and more disturbance adapted than those farther east.

  5. Edge instabilities of topological superconductors

    NASA Astrophysics Data System (ADS)

    Hofmann, Johannes S.; Assaad, Fakher F.; Schnyder, Andreas P.

    2016-05-01

    Nodal topological superconductors display zero-energy Majorana flat bands at generic edges. The flatness of these edge bands, which is protected by time-reversal and translation symmetry, gives rise to an extensive ground-state degeneracy. Therefore, even arbitrarily weak interactions lead to an instability of the flat-band edge states towards time-reversal and translation-symmetry-broken phases, which lift the ground-state degeneracy. We examine the instabilities of the flat-band edge states of dx y-wave superconductors by performing a mean-field analysis in the Majorana basis of the edge states. The leading instabilities are Majorana mass terms, which correspond to coherent superpositions of particle-particle and particle-hole channels in the fermionic language. We find that attractive interactions induce three different mass terms. One is a coherent superposition of imaginary s -wave pairing and current order, and another combines a charge-density-wave and finite-momentum singlet pairing. Repulsive interactions, on the other hand, lead to ferromagnetism together with spin-triplet pairing at the edge. Our quantum Monte Carlo simulations confirm these findings and demonstrate that these instabilities occur even in the presence of strong quantum fluctuations. We discuss the implications of our results for experiments on cuprate high-temperature superconductors.

  6. Kinematics and Control of Robot Manipulators

    NASA Astrophysics Data System (ADS)

    Paden, Bradley Evan

    This dissertation focuses on the kinematics and control of robot manipulators. The contribution to kinematics is a fundamental theorem on the design of manipulators with six revolute joints. The theorem states, roughly speaking, that manipulators which have six revolute joints and are modeled after the human arm are optimal and essentially unique. In developing the mathematical framework to prove this theorem, we define precisely the notions of length of a manipulator, well-connected-workspace, and work-volume. We contribute to control a set of analysis techniques for the design of variable structure (sliding mode) controllers for manipulators. The organization of the dissertation is the following. After introductory remarks in chapter one, the group of proper rigid motions, G, is introduced in chapter two. The tangent bundle of G is introduced and it is shown that the velocity of a rigid body can be represented by an element in the Lie algebra of G (commonly called a twist). Further, rigid motions which are exponentials of twists are used to describe four commonly occurring subproblems in robot kinematics. In chapter three, the exponentials of twists are used to write the forward kinematic map of robot manipulators and the subproblems of chapter two are used to solve the Stanford manipulator and an elbow manipulator. Chapter four focuses on manipulator singularities. Twist coordinates are used to find critical points of the forward kinematic map. The contribution to kinematics is contained in chapter five where a mathematical framework for studying the relationship between the design of 6R manipulators and their performance is developed. Chapter seven contains the contribution to control. The work of A. F. Filippov on differential equations with discontinuous right-hand-side and the work of F. H. Clarke on generalized gradients are combined to obtain a calculus for analyzing nonsmooth gradient systems. The techniques developed are applied to design a simple

  7. Kinematic problem of rigid body orientation control

    NASA Astrophysics Data System (ADS)

    Plotnikov, P. K.; Sergeev, A. N.; Chelnokov, Iu. N.

    1991-10-01

    The problem of reducing a coordinate system linked with a rigid body to a reference coordinate system rotating with a specified (programmed) angular velocity is analyzed using a kinematic formulation. The mathematic model of motion includes kinematic equations of the angular motion of a rigid body in nonnormalized quaternions; used as the controls are projections of the absolute angular velocity of body rotation to the coordinate axes. Two kinds of correction are proposed which represent quaternion analogs of the positional and integral corrections. Linear error equations for the orientation control system are obtained for the types of correction proposed here.

  8. KINEMATIC DISTANCES OF GALACTIC PLANETARY NEBULAE

    SciTech Connect

    Yang, A. Y.; Tian, W. W.; Zhu, H.; Wu, D.; Leahy, D. A. E-mail: ayyang@bao.ac.cn

    2016-03-15

    We construct H i absorption spectra for 18 planetary nebulae (PNs) and their background sources using data from the International Galactic Plane Survey. We estimate the kinematic distances of these PNs, among which 15 objects’ kinematic distances are obtained for the first time. The distance uncertainties of 13 PNs range from 10% to 50%, which is a significant improvement with uncertainties of a factor of two or three smaller than most previous distance measurements. We confirm that PN G030.2−00.1 is not a PN because of its large distance found here.

  9. Kinematic synthesis of adjustable robotic mechanisms

    NASA Astrophysics Data System (ADS)

    Chuenchom, Thatchai

    1993-01-01

    Conventional hard automation, such as a linkage-based or a cam-driven system, provides high speed capability and repeatability but not the flexibility required in many industrial applications. The conventional mechanisms, that are typically single-degree-of-freedom systems, are being increasingly replaced by multi-degree-of-freedom multi-actuators driven by logic controllers. Although this new trend in sophistication provides greatly enhanced flexibility, there are many instances where the flexibility needs are exaggerated and the associated complexity is unnecessary. Traditional mechanism-based hard automation, on the other hand, neither can fulfill multi-task requirements nor are cost-effective mainly due to lack of methods and tools to design-in flexibility. This dissertation attempts to bridge this technological gap by developing Adjustable Robotic Mechanisms (ARM's) or 'programmable mechanisms' as a middle ground between high speed hard automation and expensive serial jointed-arm robots. This research introduces the concept of adjustable robotic mechanisms towards cost-effective manufacturing automation. A generalized analytical synthesis technique has been developed to support the computational design of ARM's that lays the theoretical foundation for synthesis of adjustable mechanisms. The synthesis method developed in this dissertation, called generalized adjustable dyad and triad synthesis, advances the well-known Burmester theory in kinematics to a new level. While this method provides planar solutions, a novel patented scheme is utilized for converting prescribed three-dimensional motion specifications into sets of planar projections. This provides an analytical and a computational tool for designing adjustable mechanisms that satisfy multiple sets of three-dimensional motion specifications. Several design issues were addressed, including adjustable parameter identification, branching defect, and mechanical errors. An efficient mathematical scheme for

  10. On the Edge: Haptic Discrimination of Edge Sharpness

    PubMed Central

    Skinner, Andy L.; Kent, Christopher; Rossiter, Jonathan M.; Benton, Christopher P.; Groen, Martin G. M.; Noyes, Jan M.

    2013-01-01

    The increasing ubiquity of haptic displays (e.g., smart phones and tablets) necessitates a better understanding of the perceptual capabilities of the human haptic system. Haptic displays will soon be capable of locally deforming to create simple 3D shapes. This study investigated the sensitivity of our haptic system to a fundamental component of shapes: edges. A novel set of eight high quality shape stimuli with test edges that varied in sharpness were fabricated in a 3D printer. In a two alternative, forced choice task, blindfolded participants were presented with two of these shapes side by side (one the reference, the other selected randomly from the remaining set of seven) and after actively exploring the test edge of each shape with the tip of their index finger, reported which shape had the sharper edge. We used a model selection approach to fit optimal psychometric functions to performance data, and from these obtained just noticeable differences and Weber fractions. In Experiment 1, participants performed the task with four different references. With sharpness defined as the angle at which one surface meets the horizontal plane, the four JNDs closely followed Weber’s Law, giving a Weber fraction of 0.11. Comparisons to previously reported Weber fractions from other haptic manipulations (e.g. amplitude of vibration) suggests we are sufficiently sensitive to changes in edge sharpness for this to be of potential utility in the design of future haptic displays. In Experiment 2, two groups of participants performed the task with a single reference but different exploration strategies; one was limited to a single touch, the other unconstrained and free to explore as they wished. As predicted, the JND in the free exploration condition was lower than that in the single touch condition, indicating exploration strategy affects sensitivity to edge sharpness. PMID:24023852

  11. Detailed stellar and gaseous kinematics of M31

    NASA Astrophysics Data System (ADS)

    Opitsch, Michael; Fabricius, Maximilian; Saglia, Roberto; Bender, Ralf; Williams, Michael

    2015-02-01

    We have collected optical integral field spectroscopic data for M31 with the spectrograph VIRUS-W that result in kinematic maps of unprecedented detail. These reveal the presence of two kinematically distinct gas components.

  12. Camera-Only Kinematics for Small Lunar Rovers

    NASA Astrophysics Data System (ADS)

    Fang, E.; Suresh, S.; Whittaker, W.

    2016-11-01

    Knowledge of the kinematic state of rovers is critical. Existing methods add sensors and wiring to moving parts, which can fail and adds mass and volume. This research presents a method to optically determine kinematic state using a single camera.

  13. KINEMATIC DISTANCE ASSIGNMENTS WITH H I ABSORPTION

    SciTech Connect

    Jones, Courtney; Dickey, John M.

    2012-07-01

    Using H I absorption spectra from the International Galactic Plane Survey, a new method is implemented to resolve the kinematic distance ambiguity for 75 H II regions with known systemic velocities from radio recombination lines. A further 40 kinematic distance determinations are made for H II region candidates without known systemic velocities through an investigation of the presence of H I absorption around the terminal velocity. New kinematic distance determinations can be used to further constrain spiral arm parameters and the location and extent of other structures in the Milky Way disk. H I absorption toward continuum sources beyond the solar circle is also investigated. Follow-up studies of H I at higher resolution than the 1' to 2' of existing Galactic Plane Surveys will provide kinematic distances to many more H II regions on the far side of the Galactic center. On the basis of the velocity channel summation technique developed in this paper, a much larger sample of H II regions will be analyzed in a future paper to remove the near-far distance ambiguity.

  14. KINEMATICS OF STELLAR POPULATIONS IN POSTSTARBURST GALAXIES

    SciTech Connect

    Hiner, Kyle D.; Canalizo, Gabriela E-mail: khiner@astro-udec.cl

    2015-01-20

    Poststarburst galaxies host a population of early-type stars (A or F) but simultaneously lack indicators of ongoing star formation such as [O II] emission. Two distinct stellar populations have been identified in these systems: a young poststarburst population superimposed on an older host population. We present a study of nine poststarburst galaxies with the following objectives: (1) to investigate whether and how kinematical differences between the young and old populations of stars can be measured, and (2) to gain insight into the formation mechanism of the young population in these systems. We fit high signal-to-noise spectra with two independent populations in distinct spectral regions: the Balmer region, the Mg IB region, and the Ca triplet when available. We show that the kinematics of the two populations largely track one another if measured in the Balmer region with high signal-to-noise data. Results from examining the Faber-Jackson relation and the fundamental plane indicate that these objects are not kinematically disturbed relative to more evolved spheroids. A case study of the internal kinematics of one object in our sample shows it to be pressure supported and not rotationally dominated. Overall our results are consistent with merger-induced starburst scenarios where the young population is observed during the later stages of the merger.

  15. Compton Effect with Non-Relativistic Kinematics

    ERIC Educational Resources Information Center

    Shivalingaswamy, T.; Kagali, B. A.

    2011-01-01

    In deducing the change of wavelength of x-rays scattered by atomic electrons, one normally makes use of relativistic kinematics for electrons. However, recoiling energies of the electrons are of the order of a few keV which is less than 0.2% of their rest energies. Hence the authors may ask whether relativistic formulae are really necessary. In…

  16. Kinematics of foldable discrete space cranes

    NASA Technical Reports Server (NTRS)

    Nayfeh, A. H.

    1985-01-01

    Exact kinematic description of a NASA proposed prototype foldable-deployable discrete space crane are presented. A computer program is developed which maps the geometry of the crane once controlling parameters are specified. The program uses a building block type approach in which it calculates the local coordinates of each repeating cell and then combines them with respect to a global coordinates system.

  17. Kinematic Measurements from YouTube Videos

    ERIC Educational Resources Information Center

    Ruiz, Michael J.

    2009-01-01

    Video analysis of motion has been in use now for some time. However, some teachers may not have video equipment or may be looking for innovative ways to engage students with interesting applications at no cost. The recent advent of YouTube offers opportunities for students to measure kinematic properties of real-life events using their computers.…

  18. Stellar Archeology : Chemical Compositions and Kinematics

    NASA Astrophysics Data System (ADS)

    Stringer, Bayard; Carney, Bruce

    2011-10-01

    The λ-CDM model of cosmology predicts a hierarchical formation mechanism of galaxies, with smaller units accreting to construct larger ones. The detection of merger events in external galaxies is well known, and the detection and analysis of merger remnants in the Milky Way is a key component in piecing together the history of our home galaxy. Statistical analyses of stellar kinematics in the solar neighborhood reveal much kinematic structure in the Galactic disk, but it is not readily apparent whether this structure is extragalactic or dynamical in origin. The most prominent structures are quickly identified as well known moving groups of stars such as the Hercules, Sirius, and Hyades stellar streams. Additionally, a subset of kinematically selected stars observed at McDonald Observatory are members of a stellar stream putatively identified by Amina Helmi as part of a merger remnant. A semi-automated, high resolution spectral analysis is applied to 504 F and G dwarf stars, and the results are amenable to Kolmogorov-Smirnov membership hypothesis testing. In all four cases, the kinematic streams have chemistries roughly consistent with the Galactic disk trends, although the statistical analyses suggest some subtle differences.

  19. ANALYTIC MODELING OF THE MORETON WAVE KINEMATICS

    SciTech Connect

    Temmer, M.; Veronig, A. M.

    2009-09-10

    The issue whether Moreton waves are flare-ignited or coronal mass ejection (CME)-driven, or a combination of both, is still a matter of debate. We develop an analytical model describing the evolution of a large-amplitude coronal wave emitted by the expansion of a circular source surface in order to mimic the evolution of a Moreton wave. The model results are confronted with observations of a strong Moreton wave observed in association with the X3.8/3B flare/CME event from 2005 January 17. Using different input parameters for the expansion of the source region, either derived from the real CME observations (assuming that the upward moving CME drives the wave), or synthetically generated scenarios (expanding flare region, lateral expansion of the CME flanks), we calculate the kinematics of the associated Moreton wave signature. Those model input parameters are determined which fit the observed Moreton wave kinematics best. Using the measured kinematics of the upward moving CME as the model input, we are not able to reproduce the observed Moreton wave kinematics. The observations of the Moreton wave can be reproduced only by applying a strong and impulsive acceleration for the source region expansion acting in a piston mechanism scenario. Based on these results we propose that the expansion of the flaring region or the lateral expansion of the CME flanks is more likely the driver of the Moreton wave than the upward moving CME front.

  20. A study of slanted-edge MTF stability and repeatability

    NASA Astrophysics Data System (ADS)

    Roland, Jackson K. M.

    2015-01-01

    The slanted-edge method of measuring the spatial frequency response (SFR) as an approximation of the modulation transfer function (MTF) has become a well known and widely used image quality testing method over the last 10 years. This method has been adopted by multiple international standards including ISO and IEEE. Nearly every commercially available image quality testing software includes the slanted-edge method and there are numerous open-source algorithms available. This method is one of the most important image quality algorithms in use today. This paper explores test conditions and the impacts they have on the stability and precision of the slanted-edge method as well as details of the algorithm itself. Real world and simulated data are used to validate the characteristics of the algorithm. Details of the target such as edge angle and contrast ratio are tested to determine the impact on measurement under various conditions. The original algorithm defines a near vertical edge so that errors introduced are minor but the theory behind the algorithm requires a perfectly vertical edge. A correction factor is introduced as a way to compensate for this problem. Contrast ratio is shown to have no impact on results in an absence of noise.

  1. Advanced control schemes and kinematic analysis for a kinematically redundant 7 DOF manipulator

    NASA Technical Reports Server (NTRS)

    Nguyen, Charles C.; Zhou, Zhen-Lei

    1990-01-01

    The kinematic analysis and control of a kinematically redundant manipulator is addressed. The manipulator is the slave arm of a telerobot system recently built at Goddard Space Flight Center (GSFC) to serve as a testbed for investigating research issues in telerobotics. A forward kinematic transformation is developed in its most simplified form, suitable for real-time control applications, and the manipulator Jacobian is derived using the vector cross product method. Using the developed forward kinematic transformation and quaternion representation of orientation matrices, we perform computer simulation to evaluate the efficiency of the Jacobian in converting joint velocities into Cartesian velocities and to investigate the accuracy of Jacobian pseudo-inverse for various sampling times. The equivalence between Cartesian velocities and quaternion is also verified using computer simulation. Three control schemes are proposed and discussed for controlling the motion of the slave arm end-effector.

  2. Real time markerless motion tracking using linked kinematic chains

    DOEpatents

    Luck, Jason P.; Small, Daniel E.

    2007-08-14

    A markerless method is described for tracking the motion of subjects in a three dimensional environment using a model based on linked kinematic chains. The invention is suitable for tracking robotic, animal or human subjects in real-time using a single computer with inexpensive video equipment, and does not require the use of markers or specialized clothing. A simple model of rigid linked segments is constructed of the subject and tracked using three dimensional volumetric data collected by a multiple camera video imaging system. A physics based method is then used to compute forces to align the model with subsequent volumetric data sets in real-time. The method is able to handle occlusion of segments and accommodates joint limits, velocity constraints, and collision constraints and provides for error recovery. The method further provides for elimination of singularities in Jacobian based calculations, which has been problematic in alternative methods.

  3. Time-Dependent Kinematics of Complex Human Structures

    NASA Astrophysics Data System (ADS)

    Shaibani, Saami J.

    2013-03-01

    The human body can be arranged in numerous geometrical configurations, including many interesting scenarios from the sport of gymnastics. One particularly challenging analytical example among these is the forward flip with maximum separation from the ground at the apex of the flight. The temporal aspects of this move involve the evaluation of multiple different positions during the trajectory, which adds significantly to the effort required. When a forward flip was executed during a football game, ready access to the recording of this allowed a detailed kinematic examination to be performed. Careful application of highly intricate protocols produces results which are consistent with similar athletic environments. The emphasis in this research is to transcend standard approaches elsewhere, which are severely limited to generic athletes and/or generic circumstances. Pedagogical benefits of the rigorous methodology adopted here are explored beyond what was introduced in a recent related study.

  4. The Maiden Voyage of a Kinematics Robot

    NASA Astrophysics Data System (ADS)

    Greenwolfe, Matthew L.

    2015-04-01

    In a Montessori preschool classroom, students work independently on tasks that absorb their attention in part because the apparatus are carefully designed to make mistakes directly observable and limit exploration to one aspect or dimension. Control of error inheres in the apparatus itself, so that teacher intervention can be minimal.1 Inspired by this example, I created a robotic kinematics apparatus that also shapes the inquiry experience. Students program the robot by drawing kinematic graphs on a computer and then observe its motion. Exploration is at once limited to constant velocity and constant acceleration motion, yet open to complex multi-segment examples difficult to achieve in the lab in other ways. The robot precisely and reliably produces the motion described by the students' graphs, so that the apparatus itself provides immediate visual feedback about whether their understanding is correct as they are free to explore within the hard-coded limits. In particular, the kinematic robot enables hands-on study of multi-segment constant velocity situations, which lays a far stronger foundation for the study of accelerated motion. When correction is anonymous—just between one group of lab partners and their robot—students using the kinematic robot tend to flow right back to work because they view the correction as an integral part of the inquiry learning process. By contrast, when correction occurs by the teacher and/or in public (e.g., returning a graded assignment or pointing out student misconceptions during class), students all too often treat the event as the endpoint to inquiry. Furthermore, quantitative evidence shows a large gain from pre-test to post-test scores using the Test of Understanding Graphs in Kinematics (TUG-K).

  5. Image recovery from edge primitives

    NASA Technical Reports Server (NTRS)

    Alter-Gartenberg, Rachel; Huck, Friedrich O.; Narayanswamy, Ramkumar

    1990-01-01

    A method for extracting edge primitives from Mach-band patterns is presented together with a method for recovering image representations of features outlined by the edge boundaries. The accuracy, stability, and resolution of these representations are assessed. Since these representations are most commonly used in characterizing targets, this method of low-level processing offers new opportunities for computer vision and high data-compressing coding. Two bandpass filters are considered, the spatially invariant Laplacian of Gaussian filter and spatially variant intensity-dependent spatial (IDS) summation. It is shown that the recovery from the IDS bandpass data is particularly advantageous in applications for which robustness to local and temporal variations in illumination is important. It is concluded that the edge primitives extracted from bandpassed images can be an efficient way to store, transmit, and represent images.

  6. Upper Limb Assessment in Tetraplegia: Clinical, Functional and Kinematic Correlations

    ERIC Educational Resources Information Center

    Cacho, Enio Walker Azevedo; de Oliveira, Roberta; Ortolan, Rodrigo L.; Varoto, Renato; Cliquet, Alberto

    2011-01-01

    The aim of this study was to correlate clinical and functional evaluations with kinematic variables of upper limp reach-to-grasp movement in patients with tetraplegia. Twenty chronic patients were selected to perform reach-to-grasp kinematic assessment using a target placed at a distance equal to the arm's length. Kinematic variables (hand peak…

  7. Scattering theory for graphene plasmons near edges and interfaces

    NASA Astrophysics Data System (ADS)

    Rodin, Aleksandr; Fogler, Michael

    2012-02-01

    Motivated by recent infrared nano-imaging experiments, we study eigenmodes of graphene plasmons near sample boundaries, corners, and interfaces. Such modes can be understood as standing-wave patters formed by multiple scattering of elementary waves. We derive the rules of the corresponding scattering theory by analyzing the integro-differential equation for the plasmon dynamics. Our analytical results include the solution for the edge reflection problem in uniform graphene and a quasiclassical formalism for graphene of slowly varying density. Numerical simulations are employed for more complicated boundary geometries (wedge, constriction, etc.) and for singular density distributions that exist near the edge of a gated graphene.

  8. Investigation of acoustic streaming patterns around oscillating sharp edges

    PubMed Central

    Nama, Nitesh; Huang, Po-Hsun; Huang, Tony Jun; Costanzo, Francesco

    2014-01-01

    Oscillating sharp edges have been employed to achieve rapid and homogeneous mixing in microchannels using acoustic streaming. Here we use a perturbation approach to study the flow around oscillating sharp edges in a microchannel. This work extends prior experimental studies to numerically characterize the effect of various parameters on the acoustically induced flow. Our numerical results match well with the experimental results. We investigated multiple device parameters such as the tip angle, oscillation amplitude, and channel dimensions. Our results indicate that, due to the inherent nonlinearity of acoustic streaming, the channel dimensions could significantly impact the flow patterns and device performance. PMID:24903475

  9. Automated quantification of lumbar vertebral kinematics from dynamic fluoroscopic sequences

    NASA Astrophysics Data System (ADS)

    Camp, Jon; Zhao, Kristin; Morel, Etienne; White, Dan; Magnuson, Dixon; Gay, Ralph; An, Kai-Nan; Robb, Richard

    2009-02-01

    We hypothesize that the vertebra-to-vertebra patterns of spinal flexion and extension motion of persons with lower back pain will differ from those of persons who are pain-free. Thus, it is our goal to measure the motion of individual lumbar vertebrae noninvasively from dynamic fluoroscopic sequences. Two-dimensional normalized mutual information-based image registration was used to track frame-to-frame motion. Software was developed that required the operator to identify each vertebra on the first frame of the sequence using a four-point "caliper" placed at the posterior and anterior edges of the inferior and superior end plates of the target vertebrae. The program then resolved the individual motions of each vertebra independently throughout the entire sequence. To validate the technique, 6 cadaveric lumbar spine specimens were potted in polymethylmethacrylate and instrumented with optoelectric sensors. The specimens were then placed in a custom dynamic spine simulator and moved through flexion-extension cycles while kinematic data and fluoroscopic sequences were simultaneously acquired. We found strong correlation between the absolute flexionextension range of motion of each vertebra as recorded by the optoelectric system and as determined from the fluoroscopic sequence via registration. We conclude that this method is a viable way of noninvasively assessing twodimensional vertebral motion.

  10. The SLUGGS survey: wide-field stellar kinematics of early-type galaxies

    SciTech Connect

    Arnold, Jacob A.; Romanowsky, Aaron J.; Brodie, Jean P.; Woodley, Kristin A.; Forbes, Duncan A.; Blom, Christina; Kartha, Sreeja S.; Pastorello, Nicola; Pota, Vincenzo; Usher, Christopher; Strader, Jay; Spitler, Lee R.; Foster, Caroline

    2014-08-20

    We present stellar kinematics of 22 nearby early-type galaxies (ETGs), based on two-dimensional (2D) absorption line stellar spectroscopy out to ∼2-4 R {sub e} (effective radii), as part of the ongoing SLUGGS Survey. The galaxies span a factor of 20 in intrinsic luminosity, as well as a full range of environment and ETG morphology. Our data consist of good velocity resolution (σ{sub inst} ∼ 25 km s{sup –1}) integrated stellar-light spectra extracted from the individual slitlets of custom made Keck/DEIMOS slitmasks. We extract stellar kinematics measurements (V, σ, h {sub 3}, and h {sub 4}) for each galaxy. Combining with literature values from smaller radii, we present 2D spatially resolved maps of the large-scale kinematic structure in each galaxy. We find that the kinematic homogeneity found inside 1 R {sub e} often breaks down at larger radii, where a variety of kinematic behaviors are observed. While central slow rotators remain slowly rotating in their halos, central fast rotators show more diversity, ranging from rapidly increasing to rapidly declining specific angular momentum profiles in the outer regions. There are indications that the outer trends depend on morphological type, raising questions about the proposed unification of the elliptical and lenticular (S0) galaxy families in the ATLAS{sup 3D} survey. Several galaxies in our sample show multiple lines of evidence for distinct disk components embedded in more slowly rotating spheroids, and we suggest a joint photometric-kinematic approach for robust bulge-disk decomposition. Our observational results appear generally consistent with a picture of two-phase (in-situ plus accretion) galaxy formation.

  11. The SLUGGS Survey: Wide-field Stellar Kinematics of Early-type Galaxies

    NASA Astrophysics Data System (ADS)

    Arnold, Jacob A.; Romanowsky, Aaron J.; Brodie, Jean P.; Forbes, Duncan A.; Strader, Jay; Spitler, Lee R.; Foster, Caroline; Blom, Christina; Kartha, Sreeja S.; Pastorello, Nicola; Pota, Vincenzo; Usher, Christopher; Woodley, Kristin A.

    2014-08-01

    We present stellar kinematics of 22 nearby early-type galaxies (ETGs), based on two-dimensional (2D) absorption line stellar spectroscopy out to ~2-4 R e (effective radii), as part of the ongoing SLUGGS Survey. The galaxies span a factor of 20 in intrinsic luminosity, as well as a full range of environment and ETG morphology. Our data consist of good velocity resolution (σinst ~ 25 km s-1) integrated stellar-light spectra extracted from the individual slitlets of custom made Keck/DEIMOS slitmasks. We extract stellar kinematics measurements (V, σ, h 3, and h 4) for each galaxy. Combining with literature values from smaller radii, we present 2D spatially resolved maps of the large-scale kinematic structure in each galaxy. We find that the kinematic homogeneity found inside 1 R e often breaks down at larger radii, where a variety of kinematic behaviors are observed. While central slow rotators remain slowly rotating in their halos, central fast rotators show more diversity, ranging from rapidly increasing to rapidly declining specific angular momentum profiles in the outer regions. There are indications that the outer trends depend on morphological type, raising questions about the proposed unification of the elliptical and lenticular (S0) galaxy families in the ATLAS3D survey. Several galaxies in our sample show multiple lines of evidence for distinct disk components embedded in more slowly rotating spheroids, and we suggest a joint photometric-kinematic approach for robust bulge-disk decomposition. Our observational results appear generally consistent with a picture of two-phase (in-situ plus accretion) galaxy formation.

  12. Edge Coloring, Polyhedra and Probability

    DTIC Science & Technology

    1998-11-01

    also \\dBi{v)-\\dB*{v)\\ < i<Jand|m Al(5J)- idef (SJ)| < | . t f ll t t \\8\\ {\\ | X ^ n(J follows from (a) and ±A < |B?| < 3A. D Preparing the marking...chromatic index of G and is denoted by x ’{G). We consider the edge coloring problem in the framework of the relationship between an integer program and its...linear programming relaxation. To do this we first formulate edge coloring as an integer program and let x *(G) be the optimum of the linear

  13. Active edge control in the precessions polishing process for manufacturing large mirror segments

    NASA Astrophysics Data System (ADS)

    Li, Hongyu; Zhang, Wei; Walker, David; Yu, Gouyo

    2014-09-01

    The segmentation of the primary mirror is the only promising solution for building the next generation of ground telescopes. However, manufacturing segmented mirrors presents its own challenges. The edge mis-figure impacts directly on the telescope's scientific output. The `Edge effect' significantly dominates the polishing precision. Therefore, the edge control is regarded as one of the most difficult technical issues in the segment production that needs to be addressed urgently. This paper reports an active edge control technique for the mirror segments fabrication using the Precession's polishing technique. The strategy in this technique requires that the large spot be selected on the bulk area for fast polishing, and the small spot is used for edge figuring. This can be performed by tool lift and optimizing the dell time to compensate for non-uniform material removal at the edge zone. This requires accurate and stable edge tool influence functions. To obtain the full tool influence function at the edge, we have demonstrated in previous work a novel hybrid-measurement method which uses both simultaneous phase interferometry and profilometry. In this paper, the edge effect under `Bonnet tool' polishing is investigated. The pressure distribution is analyzed by means of finite element analysis (FEA). According to the `Preston' equation, the shape of the edge tool influence functions is predicted. With this help, the multiple process parameters at the edge zone are optimized. This is demonstrated on a 200mm crosscorners hexagonal part with a result of PV less than 200nm for entire surface.

  14. Hand kinematics of piano playing

    PubMed Central

    Flanders, Martha; Soechting, John F.

    2011-01-01

    Dexterous use of the hand represents a sophisticated sensorimotor function. In behaviors such as playing the piano, it can involve strong temporal and spatial constraints. The purpose of this study was to determine fundamental patterns of covariation of motion across joints and digits of the human hand. Joint motion was recorded while 5 expert pianists played 30 excerpts from musical pieces, which featured ∼50 different tone sequences and fingering. Principal component analysis and cluster analysis using an expectation-maximization algorithm revealed that joint velocities could be categorized into several patterns, which help to simplify the description of the movements of the multiple degrees of freedom of the hand. For the thumb keystroke, two distinct patterns of joint movement covariation emerged and they depended on the spatiotemporal patterns of the task. For example, the thumb-under maneuver was clearly separated into two clusters based on the direction of hand translation along the keyboard. While the pattern of the thumb joint velocities differed between these clusters, the motions at the metacarpo-phalangeal and proximal-phalangeal joints of the four fingers were more consistent. For a keystroke executed with one of the fingers, there were three distinct patterns of joint rotations, across which motion at the striking finger was fairly consistent, but motion of the other fingers was more variable. Furthermore, the amount of movement spillover of the striking finger to the adjacent fingers was small irrespective of the finger used for the keystroke. These findings describe an unparalleled amount of independent motion of the fingers. PMID:21880938

  15. Role of Edges in Complex Network Epidemiology

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Jiang, Zhi-Hong; Wang, Hui; Xie, Fei; Chen, Chao

    2012-09-01

    In complex network epidemiology, diseases spread along contacting edges between individuals and different edges may play different roles in epidemic outbreaks. Quantifying the efficiency of edges is an important step towards arresting epidemics. In this paper, we study the efficiency of edges in general susceptible-infected-recovered models, and introduce the transmission capability to measure the efficiency of edges. Results show that deleting edges with the highest transmission capability will greatly decrease epidemics on scale-free networks. Basing on the message passing approach, we get exact mathematical solution on configuration model networks with edge deletion in the large size limit.

  16. Supporting interactive graph exploration using edge plucking

    NASA Astrophysics Data System (ADS)

    Wong, Nelson; Carpendale, Sheelagh

    2007-01-01

    Excessive edge density in graphs can cause serious readability issues, which in turn can make the graphs difficult to understand or even misleading. Recently, we introduced the idea of providing tools that offer interactive edge bending as a method by which edge congestion can be disambiguated. We extend this direction, presenting a new tool, Edge Plucking, which offers new interactive methods to clarify node-edge relationships. Edge Plucking expands the number of situations in which interactive graph exploration tools can be used to address edge congestion.

  17. Edge enhanced morphology for infrared image analysis

    NASA Astrophysics Data System (ADS)

    Bai, Xiangzhi; Liu, Haonan

    2017-01-01

    Edge information is one of the critical information for infrared images. Morphological operators have been widely used for infrared image analysis. However, the edge information in infrared image is weak and the morphological operators could not well utilize the edge information of infrared images. To strengthen the edge information in morphological operators, the edge enhanced morphology is proposed in this paper. Firstly, the edge enhanced dilation and erosion operators are given and analyzed. Secondly, the pseudo operators which are derived from the edge enhanced dilation and erosion operators are defined. Finally, the applications for infrared image analysis are shown to verify the effectiveness of the proposed edge enhanced morphological operators. The proposed edge enhanced morphological operators are useful for the applications related to edge features, which could be extended to wide area of applications.

  18. The influence of edge and corner evolution on plasmon properties and resonant edge effect in gold nanoplatelets.

    PubMed

    Xu, Xi-Bin; Luo, Jiang-Shan; Liu, Miao; Wang, Yu-Ying; Yi, Zao; Li, Xi-Bo; Yi, You-Gen; Tang, Yong-Jian

    2015-01-28

    In this paper a simulation of the properties of surface plasmons on gold nanoplatelets with various cross-sections inscribed in a circle and an investigation of their field distributions to assign multiple SPRs are described. The manipulated propagation can be obtained through the evolution of edges and corners. Furthermore, the particle morphology and the associated spectral positions alone do not uniquely reflect the important details of the local field distribution or the resonance modes. The plasmon modes were investigated and found to be mainly excited along the edges and in the side and sloped side surfaces. The strong field distributions can generally be found around the corners and how the plasmons transmit through the corners to adjacent edges was also investigated. Besides the plasmons excited along the edges as were found for the triangular nanoplatelets, plasmons were excited in the interior region of the triangular surfaces and were also investigated. Despite this in the infrared region, plasmon modes were found to be along the edges for the hexagonal nanoplatelets. Also, it can be seen that the change of nanoplatelet thickness can support different plasmon modes ranging from dipolar resonance mode to quadrupole resonance mode. The thickness far below the skin depth can display complex plasmon modes along the edges and on the side and sloping side surfaces as well as the strong coupling between the top and bottom surfaces. The observed plasmon resonance modes in this simulation reflect the interference of all these contributions including the plasmons along the edges and on the side surfaces. This is an essential step towards a thorough understanding of plasmon modes and the effect of edge and corner evolution in polygonous nanoplatelets.

  19. Linking cranial morphology to prey capture kinematics in three cleaner wrasses: Labroides dimidiatus, Larabicus quadrilineatus, and Thalassoma lutescens.

    PubMed

    Baliga, Vikram B; Mehta, Rita S

    2015-11-01

    Cleaner fishes are well known for removing and consuming ectoparasites off other taxa. Observers have noted that cleaners continuously "pick" ectoparasites from the bodies of their respective client organisms, but little is known about the kinematics of cleaning. While a recent study described the jaw morphology of cleaners as having small jaw-closing muscles and weak bite forces, it is unknown how these traits translate into jaw movements during feeding to capture and remove ectoparasites embedded in their clients. Here, we describe cranial morphology and kinematic patterns of feeding for three species of cleaner wrasses. Through high-speed videography of cleaner fishes feeding in two experimental treatments, we document prey capture kinematic profiles for Labroides dimidiatus, Larabicus quadrilineatus, and Thalassoma lutescens. Our results indicate that cleaning in labrids may be associated with the ability to perform low-displacement, fast jaw movements that allow for rapid and multiple gape cycles on individually targeted items. Finally, while the feeding kinematics of cleaners show notable similarities to those of "picker" cyprinodontiforms, we find key differences in the timing of events. In fact, cleaners generally seem to be able to capture prey twice as fast as cyprinodontiforms. We thus suggest that the kinematic patterns exhibited by cleaners are indicative of picking behavior, but that "pickers" may be more kinematically diverse than previously thought.

  20. Edge detection and texture classification by cuttlefish.

    PubMed

    Zylinski, Sarah; Osorio, Daniel; Shohet, Adam J

    2009-12-14

    Cephalopod mollusks including octopus and cuttlefish are adept at adaptive camouflage, varying their appearance to suit the surroundings. This behavior allows unique access into the vision of a non-human species because one can ask how these animals use spatial information to control their coloration pattern. There is particular interest in factors that affect the relative levels of expression of the Mottle and the Disruptive body patterns. Broadly speaking, the Mottle is displayed on continuous patterned surfaces whereas the Disruptive is used on discrete objects such as pebbles. Recent evidence from common cuttlefish, Sepia officinalis, suggests that multiple cues are relevant, including spatial scale, contrast, and depth. We analyze the body pattern responses of juvenile cuttlefish to a range of checkerboard stimuli. Our results suggest that the choice of camouflage pattern is consistent with a simple model of how cuttlefish classify visual textures, according to whether they are Uniform or patterned, and whether the pattern includes visual edges. In particular, cuttlefish appear to detect edges by sensing the relative spatial phases of two spatial frequency components (e.g., fundamental and the third harmonic Fourier component in a square wave). We discuss the relevance of these findings to vision and camouflage in aquatic environments.

  1. Shape-dependent canny edge detector

    NASA Astrophysics Data System (ADS)

    Panetta, Karen A.; Agaian, Sos S.; Nercessian, Shahan C.; Almunstashri, Ali A.

    2011-08-01

    Edges characterize the boundaries of objects in images and are informative structural cues for computer vision and target/object detection and recognition systems. The Canny edge detector is widely regarded as the edge detection standard. It is fairly adaptable to different environments, as its parametric nature attempts to tailor the detection of edges based on image-dependent characteristics or the particular requirements of a given implementation. Though it has been used in a myriad of image processing tasks, the Canny edge detector is still vulnerable to edge losses, localization errors, and noise sensitivity. These issues are largely due to the key tradeoff made in the scale and size of the edge detection filters used by the algorithm. Small-scaled filters are sensitive to edges but also to noise, whereas large-scaled filters are robust to noise but could filter out fine details. In this paper, novel edge detection kernel generalizations and a shape-dependent edge detector are introduced to alleviate these shortcomings. While most standard edge detection algorithms are based on convolving the input image with fixed size square kernels, this paper will illustrate the benefits of different filter sizes, and more importantly, different kernel shapes for edge detection. Moreover, new edge fusion methods are introduced to more effectively combine the individual edge responses. Existing edge detectors, including the Canny edge detector, can be obtained from the generalized edge detector by specifying corresponding parameters and kernel shapes. The proposed representations and edge detector have been qualitatively and quantitatively evaluated on several different types of image data. Computer simulations demonstrate that nonsquare kernel approaches can outperform square kernel approaches such as Canny, Sobel, Prewitt, Roberts, and others, providing better tradeoffs between noise rejection, accurate edge localization, and resolution. Where possible, Pratt's figure of

  2. Laplacian operator-based edge detectors.

    PubMed

    Wang, Xin

    2007-05-01

    Laplacian operator is a second derivative operator often used in edge detection. Compared with the first derivative-based edge detectors such as Sobel operator, the Laplacian operator may yield better results in edge localization. Unfortunately, the Laplacian operator is very sensitive to noise. In this paper, based on the Laplacian operator, a model is introduced for making some edge detectors. Also, the optimal threshold is introduced for obtaining a Maximum a Posteriori (MAP) estimate of edges.

  3. Introduction to Solid Edge(TM)

    NASA Technical Reports Server (NTRS)

    Smith, John C.

    1997-01-01

    Solid Edge was conceived and developed to provide breakthrough levels of productivity for engineers and designers by providing tools focused on their daily work. This user-oriented approach led to a focus on five key areas: 1) assembly-focused design, 2) ease of use, 3) plug and play software, 4) superior part modeling, and 5) production drafting. Mechanical designers work primarily with assemblies of parts that together perform a useful function. The parts themselves are principally a consequence of the function of the assembly and the interrelationships between parts. Breakthroughs in productivity will come through a focus on making the design of assemblies easier, with enhanced part design a prerequisite to that. Enhancements already in development are part to part interaction, more assembly features applying to multiple parts, exploded assemblies, assembly playback, enhanced BOM, etc.

  4. Symmetry for Flavor-Kinematics Duality from an Action

    NASA Astrophysics Data System (ADS)

    Cheung, Clifford; Shen, Chia-Hsien

    2017-03-01

    We propose a new representation of the nonlinear sigma model that exhibits a manifest duality between flavor and kinematics. The fields couple exclusively through cubic Feynman vertices which define the structure constants of an underlying kinematic algebra. The action is invariant under a combination of internal and spacetime symmetries whose conservation equations imply flavor-kinematics duality, ensuring that all Feynman diagrams satisfy kinematic Jacobi identities. Substituting flavor for kinematics, we derive a new cubic action for the special Galileon theory. In this picture, the vanishing soft behavior of amplitudes is a by-product of the Weinberg soft theorem.

  5. The Problem of the Edge.

    ERIC Educational Resources Information Center

    Faatz, Judith A.

    1998-01-01

    Describes a field study in a local ecosystem which allows high school students to investigate the edge effect, where a meadow and a forest meet. Students measure soil moisture content, soil temperature, air temperature, relative humidity, wind intensity, and illumination level. Teachers can help students apply their findings to understand problems…

  6. Reflection symmetry detection using locally affine invariant edge correspondence.

    PubMed

    Wang, Zhaozhong; Tang, Zesheng; Zhang, Xiao

    2015-04-01

    Reflection symmetry detection receives increasing attentions in recent years. The state-of-the-art algorithms mainly use the matching of intensity-based features (such as the SIFT) within a single image to find symmetry axes. This paper proposes a novel approach by establishing the correspondence of locally affine invariant edge-based features, which are superior to the intensity based in the aspects that it is insensitive to illumination variations, and applicable to textureless objects. The locally affine invariance is achieved by simple linear algebra for efficient and robust computations, making the algorithm suitable for detections under object distortions like perspective projection. Commonly used edge detectors and a voting process are, respectively, used before and after the edge description and matching steps to form a complete reflection detection pipeline. Experiments are performed using synthetic and real-world images with both multiple and single reflection symmetry axis. The test results are compared with existing algorithms to validate the proposed method.

  7. Reduction of Flap Side Edge Noise - the Blowing Flap

    NASA Technical Reports Server (NTRS)

    Hutcheson, Florence V.; Brooks, THomas F.

    2005-01-01

    A technique to reduce the noise radiating from a wing-flap side edge is being developed. As an airplane wing with an extended flap is exposed to a subsonic airflow, air is blown outward through thin rectangular chord-wise slots at various locations along the side edges and side surface of the flap to weaken and push away the vortices that originate in that region of the flap and are responsible for important noise emissions. Air is blown through the slots at up to twice the local flow velocity. The blowing is done using one or multiple slots, where a slot is located along the top, bottom or side surface of the flap along the side edge, or also along the intersection of the bottom (or top) and side surfaces.

  8. ELNES investigations of the oxygen K-edge in spinels.

    PubMed

    Docherty, F T; Craven, A J; McComb, D W; Skakle, J

    2001-02-01

    The results of a systematic study of the oxygen K-edge electron energy-loss spectroscopy (ELNES) from a series of aluminium- and chromium-containing spinels are presented. Extra fine structure in the region up to 10 eV above the edge onset is observed for the chromium-containing compounds and is assigned to transitions to states created by mixing of oxygen 2p and metal 3d orbitals. The experimental data has been simulated using the multiple scattering code, FEFF8. Good agreement was obtained in the case of magnesium aluminate, but relatively poor agreement was obtained in the case of the chromites. The possible fingerprints in the oxygen K-edge ELNES corresponding to a high degree of inversion the spinel structure and to a tetragonal distortion of the cubic structure are discussed.

  9. Development of edge effects around experimental ecosystem hotspots is affected by edge density and matrix type

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ecological edge effects are sensitive to landscape context. In particular, edge effects can be altered by matrix type and by the presence of other nearby edges. We experimentally altered patch configurations in an African savanna to determine how edge density and matrix type influence edge effect de...

  10. Surface growth kinematics via local curve evolution.

    PubMed

    Moulton, Derek E; Goriely, Alain

    2014-01-01

    A mathematical framework is developed to model the kinematics of surface growth for objects that can be generated by evolving a curve in space, such as seashells and horns. Growth is dictated by a growth velocity vector field defined at every point on a generating curve. A local orthonormal basis is attached to each point of the generating curve and the velocity field is given in terms of the local coordinate directions, leading to a fully local and elegant mathematical structure. Several examples of increasing complexity are provided, and we demonstrate how biologically relevant structures such as logarithmic shells and horns emerge as analytical solutions of the kinematics equations with a small number of parameters that can be linked to the underlying growth process. Direct access to cell tracks and local orientation enables for connections to be made to the underlying growth process.

  11. Kinematical uniqueness of homogeneous isotropic LQC

    NASA Astrophysics Data System (ADS)

    Engle, Jonathan; Hanusch, Maximilian

    2017-01-01

    In a paper by Ashtekar and Campiglia, invariance under volume preserving residual diffeomorphisms has been used to single out the standard representation of the reduced holonomy-flux algebra in homogeneous loop quantum cosmology (LQC). In this paper, we use invariance under all residual diffeomorphisms to single out the standard kinematical Hilbert space of homogeneous isotropic LQC for both the standard configuration space {{{R}}\\text{Bohr}} , as well as for the Fleischhack one {R}\\sqcup {{{R}}\\text{Bohr}} . We first determine the scale invariant Radon measures on these spaces, and then show that the Haar measure on {{{R}}\\text{Bohr}} is the only such measure for which the momentum operator is hermitian w.r.t. the corresponding inner product. In particular, the measure is forced to be identically zero on {R} in the Fleischhack case, so that for both approaches, the standard kinematical LQC-Hilbert space is singled out.

  12. Galactic warp kinematics: model vs. observations

    NASA Astrophysics Data System (ADS)

    Abedi, H.; Figueras, F.; Aguilar, L.; Mateu, C.; Romero-Gómez, M.; López-Corredoira, M.; Garzón, F.

    2015-05-01

    We test the capability of several methods to identify and characterise the warping of the stellar disc of our Galaxy in the Gaia era. We have developed a first kinematic model for the galactic warp and derived the analytical expressions for the force field of a warped Miyamoto- Nagai potential. We have generated realistic mock catalogues of OB, A and red clump stars within the warped galactic disc, where a very complete model of Gaia observables and their expected errors are included. We use the family of Great Circle Cell Counts (GC3) methods and LonKin methods for detecting and characterising the galactic warp. As a complementary work, we look into one of the existing proper motion catalogue namely the UCAC4, and look for the kinematic signature of the warp. We demonstrate the necessity of correcting for a possible residual rotation of the Hipparcos celestial reference frame with respect to the extra galactic inertial one.

  13. Kinematics of the symbiotic system R Aqr

    NASA Astrophysics Data System (ADS)

    Navarro, S.; Corral, L. J.; Steffen, W.

    2014-04-01

    We present the results of the kinematical analysis of the symbiotic system R Aqr. We obtained high dispersion spectra with the MES spectrograph at the 2.1 m telescope of San Pedro Mártir (MEZCAL). The used filter were Ha + [NII], (λc = 6575Å, Δλ = 90Å). We analyse the [NII] λλ6583 line. When the observations are compared with previous ones by Solf (1992) we detected an important change in the projected velocities of the observed knots, supporting the idea of a precessing jet. We are working also in a 3-D kinematic model for the object using the measured velocities and the state of the model is presented.

  14. Kinematics of horizontal and vertical caterpillar crawling.

    PubMed

    van Griethuijsen, Linnea I; Trimmer, Barry A

    2009-05-01

    Unlike horizontal crawling, vertical crawling involves two counteracting forces: torque rotating the body around its center of mass and gravity resisting forward movement. The influence of these forces on kinematics has been examined in the soft-bodied larval stage of Manduca sexta. We found that crawling and climbing are accomplished using the same movements, with both segment timing and proleg lift indistinguishable in horizontal and vertical locomotion. Minor differences were detected in stride length and in the delay between crawls, which led to a lower crawling speed in the vertical orientation. Although these differences were statistically significant, they were much smaller than the variation in kinematic parameters between animals. The ability of Manduca to crawl and climb using the same movements is best explained by Manduca's relatively small size, slow speed and strong, controlled, passive grip made possible by its proleg/crochets.

  15. The kinematic advantage of electric cars

    NASA Astrophysics Data System (ADS)

    Meyn, Jan-Peter

    2015-11-01

    Acceleration of a common car with with a turbocharged diesel engine is compared to the same type with an electric motor in terms of kinematics. Starting from a state of rest, the electric car reaches a distant spot earlier than the diesel car, even though the latter has a better specification for engine power and average acceleration from 0 to 100 km h-1. A three phase model of acceleration as a function of time fits the data of the electric car accurately. The first phase is a quadratic growth of acceleration in time. It is shown that the tenfold higher coefficient for the first phase accounts for most of the kinematic advantage of the electric car.

  16. SKIRT: Stellar Kinematics Including Radiative Transfer

    NASA Astrophysics Data System (ADS)

    Baes, Maarten; Dejonghe, Herwig; Davies, Jonathan

    2011-09-01

    SKIRT is a radiative transfer code based on the Monte Carlo technique. The name SKIRT, acronym for Stellar Kinematics Including Radiative Transfer, reflects the original motivation for its creation: it has been developed to study the effects of dust absorption and scattering on the observed kinematics of dusty galaxies. In a second stage, the SKIRT code was extended with a module to self-consistently calculate the dust emission spectrum under the assumption of local thermal equilibrium. This LTE version of SKIRT has been used to model the dust extinction and emission of various types of galaxies, as well as circumstellar discs and clumpy tori around active galactic nuclei. A new, extended version of SKIRT code can perform efficient 3D radiative transfer calculations including a self-consistent calculation of the dust temperature distribution and the associated FIR/submm emission with a full incorporation of the emission of transiently heated grains and PAH molecules.

  17. Characterizing Fluoroscopy Based Kinematic Accuracy as a Function of Pulse Width and Velocity

    PubMed Central

    Ellingson, Arin M.; Mozingo, Joseph D.; Magnuson, Dixon J.; Pagnano, Mark W.; Zhao, Kristin D.

    2016-01-01

    Fluoroscopic imaging has become increasingly popular to investigate total knee arthroplasty kinematics non-invasively - 3D implant models are aligned with 2D image projections, and optimized via an edge-contour alignment technique. Previous studies have quantified the accuracy of this approach, however they do not adequately address the impact of image collection parameters. A particularly sensitive parameter is the pulse width, or exposure time per frame At longer pulse widths, a more motion is captured in a single frame; this can lead to image blur and subsequent degradation to image edge quality. Therefore, the comparative accuracy of relative joint kinematics as a function of pulse width and joint velocity needs to be defined. A limits of agreement approach was taken to define the mean differences between optoelectric kinematic measures (gold standard) and fluoroscopic methods at various pulse widths (1, 8, 16ms) and knee velocities (50, 100, 225°/s). The mean absolute differences between the optoelectric and fluoroscopic methods for 1ms pulse width was less than 1.5° and 0.9mm. Comparable rotational differences (1.3°) were observed for the 8ms pulse width but had larger translational differences (1.4mm). The 16ms pulse width yielded the greatest mean differences (2.0° and 1.6mm), which increased with knee flexion velocity. The importance of pulse width and velocity should not be overlooked for future studies - this parameter has proven to be a sensitive metric in the quantification of joint motion via fluoroscopy and must be identified and reported in future studies. PMID:27769514

  18. Rajiform locomotion: three-dimensional kinematics of the pectoral fin surface during swimming in the freshwater stingray Potamotrygon orbignyi.

    PubMed

    Blevins, Erin L; Lauder, George V

    2012-09-15

    Rajiform locomotion in fishes is dominated by distinctive undulations of expanded pectoral fins. Unlike other fishes, which typically interact with the fluid environment via multiple fins, undulating rays modulate a single control surface, the pectoral disc, to perform pelagic locomotion, maneuvering and other behaviors. Complex deformations of the broad, flexible pectoral fins occur as the undulating wave varies in three dimensions; pectoral fin kinematics and changes in waveform with swimming speed cannot be fully quantified by two-dimensional analyses of the fin margin. We present the first three-dimensional analysis of undulatory rajiform locomotion in a batoid, the freshwater stingray Potamotrygon orbignyi. Using three cameras (250 frames s(-1)), we gathered three-dimensional excursion data from 31 points on the pectoral fin during swimming at 1.5 and 2.5 disc lengths s(-1), describing the propulsive wave and contrasting waveforms between swimming speeds. Only a relatively small region of the pectoral fin (~25%) undulates with significant amplitude (>0.5 cm). Stingrays can maintain extreme lateral curvature of the distal fin margin in opposition to induced hydrodynamic loads, 'cupping' the edge of the pectoral fin into the flow, with potential implications for drag reduction. Wave amplitude increases across both anteroposterior and mediolateral fin axes. Along the anteroposterior axis, amplitude increases until the wave reaches mid-disc and then remains constant, in contrast to angulliform patterns of continuous amplitude increase. Increases in swimming speed are driven by both wave frequency and wavespeed, though multivariate analyses reveal a secondary role for amplitude.

  19. Kinematics of Hooke universal joint robot wrists

    NASA Technical Reports Server (NTRS)

    Mckinney, William S., Jr.

    1988-01-01

    The singularity problem associated with wrist mechanisms commonly found on industrial manipulators can be alleviated by redesigning the wrist so that it functions as a three-axis gimbal system. This paper discussess the kinematics of gimbal robot wrists made of one and two Hooke universal joints. Derivations of the resolved rate motion control equations for the single and double Hooke universal joint wrists are presented using the three-axis gimbal system as a theoretical wrist model.

  20. Kinematic Diversity in Rorqual Whale Feeding Mechanisms.

    PubMed

    Cade, David E; Friedlaender, Ari S; Calambokidis, John; Goldbogen, Jeremy A

    2016-10-10

    Rorqual whales exhibit an extreme lunge filter-feeding strategy characterized by acceleration to high speed and engulfment of a large volume of prey-laden water [1-4]. Although tagging studies have quantified the kinematics of lunge feeding, the timing of engulfment relative to body acceleration has been modeled conflictingly because it could never be directly measured [5-7]. The temporal coordination of these processes has a major impact on the hydrodynamics and energetics of this high-cost feeding strategy [5-9]. If engulfment and body acceleration are temporally distinct, the overall cost of this dynamic feeding event would be minimized. However, greater temporal overlap of these two phases would theoretically result in higher drag and greater energetic costs. To address this discrepancy, we used animal-borne synchronized video and 3D movement sensors to quantify the kinematics of both the skull and body during feeding events. Krill-feeding blue and humpback whales exhibited temporally distinct acceleration and engulfment phases, with humpback whales reaching maximum gape earlier than blue whales. In these whales, engulfment coincided largely with body deceleration; however, humpback whales pursuing more agile fish demonstrated highly variable coordination of skull and body kinematics in the context of complex prey-herding techniques. These data suggest that rorquals modulate the coordination of acceleration and engulfment to optimize foraging efficiency by minimizing locomotor costs and maximizing prey capture. Moreover, this newfound kinematic diversity observed among rorquals indicates that the energetic efficiency of foraging is driven both by the whale's engulfment capacity and the comparative locomotor capabilities of predator and prey. VIDEO ABSTRACT.

  1. Fracture Control for NIRSpec Kinematic Mounts

    NASA Astrophysics Data System (ADS)

    Vorel, M.; Novo, F.; Jollet, D.; Sinnema, G.; Jentsch, M.

    2014-06-01

    An ESA contribution to the JWST is the Near Infra-Red Spectrograph (NIRSpec) capable of high-resolution spectroscopy. The development of the NIRSpec was commissioned to Astrium. This contribution deals with the fracture control for the optical bench kinematic (OBK) mounts which are critical structural elements of the NIRSpec platform. A summary of the main activities is given as well as difficulties encountered throughout the process and solutions adopted.

  2. Kinematics and dynamics of sphenisciform wings

    NASA Astrophysics Data System (ADS)

    Noca, Flavio; Crisinel, Fabien; Munier, Pierre

    2011-11-01

    Three-dimensional scans of three different species of taxidermied penguins (Aptenodytes patagonicus, Pygoscelis papua, and Spheniscus magellanicus) have been performed. A three-dimensional reproduction of an African penguin (Sphenicus demersus) wing was manufactured and tested in a hydrodynamic channel. A six-degree-of-freedom robot was programmed to perform the three dimensional kinematics, obtained from actual footage. A six-component force balance was used to retrieve the dynamics of the wing motion. Results will be presented and discussed.

  3. Efficient Kinematic Computations For 7-DOF Manipulators

    NASA Technical Reports Server (NTRS)

    Seraji, Homayoun; Long, Mark K.; Kreutz-Delgado, Kenneth

    1994-01-01

    Efficient algorithms for forward kinematic mappings of seven-degree-of-freedom (7-DOF) robotic manipulator having revolute joints developed on basis of representation of redundant DOF in terms of parameter called "arm angle." Continuing effort to exploit redundancy in manipulator according to concept of basic and additional tasks. Concept also discussed in "Configuration-Control Scheme Copes With Singularities" (NPO-18556) and "Increasing the Dexterity of Redundant Robots" (NPO-17801).

  4. The kinematic component of the cosmological redshift

    NASA Astrophysics Data System (ADS)

    Chodorowski, Michał J.

    2011-05-01

    It is widely believed that the cosmological redshift is not a Doppler shift. However, Bunn & Hogg have recently pointed out that to solve this problem properly, one has to transport parallelly the velocity four-vector of a distant galaxy to the observer's position. Performing such a transport along the null geodesic of photons arriving from the galaxy, they found that the cosmological redshift is purely kinematic. Here we argue that one should rather transport the velocity four-vector along the geodesic connecting the points of intersection of the world-lines of the galaxy and the observer with the hypersurface of constant cosmic time. We find that the resulting relation between the transported velocity and the redshift of arriving photons is not given by a relativistic Doppler formula. Instead, for small redshifts it coincides with the well-known non-relativistic decomposition of the redshift into a Doppler (kinematic) component and a gravitational one. We perform such a decomposition for arbitrary large redshifts and derive a formula for the kinematic component of the cosmological redshift, valid for any Friedman-Lemaître-Robertson-Walker (FLRW) cosmology. In particular, in a universe with Ωm= 0.24 and ΩΛ= 0.76, a quasar at a redshift 6, at the time of emission of photons reaching us today had the recession velocity v= 0.997c. This can be contrasted with v= 0.96c, had the redshift been entirely kinematic. Thus, for recession velocities of such high-redshift sources, the effect of deceleration of the early Universe clearly prevails over the effect of its relatively recent acceleration. Last but not the least, we show that the so-called proper recession velocities of galaxies, commonly used in cosmology, are in fact radial components of the galaxies' four-velocity vectors. As such, they can indeed attain superluminal values, but should not be regarded as real velocities.

  5. Lower extremity kinematics of athletics curve sprinting.

    PubMed

    Alt, Tobias; Heinrich, Kai; Funken, Johannes; Potthast, Wolfgang

    2015-01-01

    Curve running requires the generation of centripetal force altering the movement pattern in comparison to the straight path run. The question arises which kinematic modulations emerge while bend sprinting at high velocities. It has been suggested that during curve sprints the legs fulfil different functions. A three-dimensional motion analysis (16 high-speed cameras) was conducted to compare the segmental kinematics of the lower extremity during the stance phases of linear and curve sprints (radius: 36.5 m) of six sprinters of national competitive level. Peak joint angles substantially differed in the frontal and transversal plane whereas sagittal plane kinematics remained unchanged. During the prolonged left stance phase (left: 107.5 ms, right: 95.7 ms, straight: 104.4 ms) the maximum values of ankle eversion (left: 12.7°, right: 2.6°, straight: 6.6°), hip adduction (left: 13.8°, right: 5.5°, straight: 8.8°) and hip external rotation (left: 21.6°, right: 12.9°, straight: 16.7°) were significantly higher. The inside leg seemed to stabilise the movement in the frontal plane (eversion-adduction strategy) whereas the outside leg provided and controlled the motion in the horizontal plane (rotation strategy). These results extend the principal understanding of the effects of curve sprinting on lower extremity kinematics. This helps to increase the understanding of nonlinear human bipedal locomotion, which in turn might lead to improvements in athletic performance and injury prevention.

  6. Kinematics in irregular galaxies: NGC 4449.

    NASA Astrophysics Data System (ADS)

    Valdez, M.; Rosado, M.

    1998-11-01

    A kinematical analysis of the irregular galaxy NGC 4449 is presented based on the Fabry-Perot interferometer PUMA observations. In NGC 4449 we analyse its global velocity field, HII regions population as well as the SNR population identified on radioastronomy studies. Our first results for NGC 4449 show that the optical velocity field, presents a decreasing gradient in velocity along the optical bar and an anticorrelation with respect to the velocity field of the HI halo.

  7. Kinematics and dynamics of the Uranian rings

    NASA Technical Reports Server (NTRS)

    French, Richard G.

    1987-01-01

    The self-gravity model of apse alignment was tested by comparing its predictions about structure within the epsilon ring with an extensive set of observed occultation profiles covering a wide range of ring longitudes. The self-gravity model as presently constructed is inconsistent with the observations. The Lindblad resonance survey and Shepherd satellite ring perturbation are discussed. The kinematic model of the Uranian ring orbit was enhanced to accommodate Voyager observations as well as ground-based occultation observations.

  8. Photon Counting Using Edge-Detection Algorithm

    NASA Technical Reports Server (NTRS)

    Gin, Jonathan W.; Nguyen, Danh H.; Farr, William H.

    2010-01-01

    New applications such as high-datarate, photon-starved, free-space optical communications require photon counting at flux rates into gigaphoton-per-second regimes coupled with subnanosecond timing accuracy. Current single-photon detectors that are capable of handling such operating conditions are designed in an array format and produce output pulses that span multiple sample times. In order to discern one pulse from another and not to overcount the number of incoming photons, a detection algorithm must be applied to the sampled detector output pulses. As flux rates increase, the ability to implement such a detection algorithm becomes difficult within a digital processor that may reside within a field-programmable gate array (FPGA). Systems have been developed and implemented to both characterize gigahertz bandwidth single-photon detectors, as well as process photon count signals at rates into gigaphotons per second in order to implement communications links at SCPPM (serial concatenated pulse position modulation) encoded data rates exceeding 100 megabits per second with efficiencies greater than two bits per detected photon. A hardware edge-detection algorithm and corresponding signal combining and deserialization hardware were developed to meet these requirements at sample rates up to 10 GHz. The photon discriminator deserializer hardware board accepts four inputs, which allows for the ability to take inputs from a quadphoton counting detector, to support requirements for optical tracking with a reduced number of hardware components. The four inputs are hardware leading-edge detected independently. After leading-edge detection, the resultant samples are ORed together prior to deserialization. The deserialization is performed to reduce the rate at which data is passed to a digital signal processor, perhaps residing within an FPGA. The hardware implements four separate analog inputs that are connected through RF connectors. Each analog input is fed to a high-speed 1

  9. Application of Machine Learning in Postural Control Kinematics for the Diagnosis of Alzheimer's Disease

    PubMed Central

    Yelshyna, Darya; Bicho, Estela

    2016-01-01

    The use of wearable devices to study gait and postural control is a growing field on neurodegenerative disorders such as Alzheimer's disease (AD). In this paper, we investigate if machine-learning classifiers offer the discriminative power for the diagnosis of AD based on postural control kinematics. We compared Support Vector Machines (SVMs), Multiple Layer Perceptrons (MLPs), Radial Basis Function Neural Networks (RBNs), and Deep Belief Networks (DBNs) on 72 participants (36 AD patients and 36 healthy subjects) exposed to seven increasingly difficult postural tasks. The decisional space was composed of 18 kinematic variables (adjusted for age, education, height, and weight), with or without neuropsychological evaluation (Montreal cognitive assessment (MoCA) score), top ranked in an error incremental analysis. Classification results were based on threefold cross validation of 50 independent and randomized runs sets: training (50%), test (40%), and validation (10%). Having a decisional space relying solely on postural kinematics, accuracy of AD diagnosis ranged from 71.7 to 86.1%. Adding the MoCA variable, the accuracy ranged between 91 and 96.6%. MLP classifier achieved top performance in both decisional spaces. Having comprehended the interdynamic interaction between postural stability and cognitive performance, our results endorse machine-learning models as a useful tool for computer-aided diagnosis of AD based on postural control kinematics. PMID:28074090

  10. Kinematic control of extreme jump angles in the red leg running frog (Kassina maculata).

    PubMed

    Richards, Christopher Thomas; Porro, Laura Beatriz; Collings, Amber Jade

    2017-03-08

    The kinematic flexibility of frog hindlimbs enables multiple locomotor modes within a single species. Prior work has extensively explored maximum performance capacity in frogs; however, the mechanisms by which anurans modulate performance within locomotor modes remain unclear. We explored how Kassina maculata, a species known for both running and jumping abilities, modulates takeoff angle from horizontal to nearly vertical. Specifically, how do 3D motions of leg segments coordinate to move the center of mass (COM) upwards and forwards? How do joint rotations modulate jump angle? High-speed video was used to quantify 3D joint angles and their respective rotation axis vectors. Inverse kinematics was used to determine how hip, knee and ankle rotations contribute to components of COM motion. Independent of takeoff angle, leg segment retraction (rearward rotation) was twofold greater than adduction (downward rotation). Additionally, the joint rotation axis vectors reoriented through time suggesting dynamic shifts in relative roles of joints. We found two hypothetical mechanisms for increasing takeoff angle: Firstly, greater knee and ankle excursion increased shank adduction, elevating the COM. Secondly, during the steepest jumps the body rotated rapidly backwards to redirect the COM velocity. This rotation was not caused by pelvic angle extension, but rather by kinematic transmission from leg segments via reorientation of the joint rotation axes. We propose that K. maculata uses proximal leg retraction as the principal kinematic drive while dynamically tuning jump trajectory by knee and ankle joint modulation.

  11. Three-dimensional trunk kinematics in golf: between-club differences and relationships to clubhead speed.

    PubMed

    Joyce, Christopher; Burnett, Angus; Cochrane, Jodie; Ball, Kevin

    2013-06-01

    The aims of this study were (i) to determine whether significant three-dimensional (3D) trunk kinematic differences existed between a driver and a five-iron during a golf swing; and (ii) to determine the anthropometric, physiological, and trunk kinematic variables associated with clubhead speed. Trunk range of motion and golf swing kinematic data were collected from 15 low-handicap male golfers (handicap = 2.5 +/- 1.9). Data were collected using a 10-camera motion capture system operating at 250 Hz. Data on clubhead speed and ball velocity were collected using a real-time launch monitor. Paired t-tests revealed nine significant (p < or = 0.0019) between-club differences for golf swing kinematics, namely trunk and lower trunk flexion/extension and lower trunk axial rotation. Multiple regression analyses explained 33.7-66.7% of the variance in clubhead speed for the driver and five-iron, respectively, with both trunk and lower trunk variables showing associations with clubhead speed. Future studies should consider the role of the upper limbs and modifiable features of the golf club in developing clubhead speed for the driver in particular.

  12. Application of Machine Learning in Postural Control Kinematics for the Diagnosis of Alzheimer's Disease.

    PubMed

    Costa, Luís; Gago, Miguel F; Yelshyna, Darya; Ferreira, Jaime; David Silva, Hélder; Rocha, Luís; Sousa, Nuno; Bicho, Estela

    2016-01-01

    The use of wearable devices to study gait and postural control is a growing field on neurodegenerative disorders such as Alzheimer's disease (AD). In this paper, we investigate if machine-learning classifiers offer the discriminative power for the diagnosis of AD based on postural control kinematics. We compared Support Vector Machines (SVMs), Multiple Layer Perceptrons (MLPs), Radial Basis Function Neural Networks (RBNs), and Deep Belief Networks (DBNs) on 72 participants (36 AD patients and 36 healthy subjects) exposed to seven increasingly difficult postural tasks. The decisional space was composed of 18 kinematic variables (adjusted for age, education, height, and weight), with or without neuropsychological evaluation (Montreal cognitive assessment (MoCA) score), top ranked in an error incremental analysis. Classification results were based on threefold cross validation of 50 independent and randomized runs sets: training (50%), test (40%), and validation (10%). Having a decisional space relying solely on postural kinematics, accuracy of AD diagnosis ranged from 71.7 to 86.1%. Adding the MoCA variable, the accuracy ranged between 91 and 96.6%. MLP classifier achieved top performance in both decisional spaces. Having comprehended the interdynamic interaction between postural stability and cognitive performance, our results endorse machine-learning models as a useful tool for computer-aided diagnosis of AD based on postural control kinematics.

  13. Predicting three-dimensional patellofemoral kinematics from static imaging-based alignment measures.

    PubMed

    Freedman, Benjamin R; Sheehan, Frances T

    2013-03-01

    Patellofemoral pain syndrome causes significant discomfort and disability among much of the general population. Despite recent breakthroughs in dynamic three-dimensional imaging technologies to assess pathological patellofemoral motion, such tools remain costly for clinical diagnostics applications. Thus, this study investigated whether three-dimensional patellofemoral kinematics could be predicted from routine two-dimensional static measures of patellofemoral joint alignment quantified from magnetic resonance imaging (MRI) data acquired in full knee extension. Twenty-six volunteers clinically diagnosed with patellofemoral pain (19 F/7 M, 25.9 ± 11.1 years) and 26 control subjects (19 F/7 M, 25.3 ± 7.7 years) were included in this IRB-approved study. Static three-dimensional sagittal T1-weighted gradient recall echo and dynamic MRI scans were acquired. For the dynamic image acquisition, subjects cyclically flexed and extended their knee (at 30 cycles/min) while a full cine-phase contrast MRI set (24 time frames of anatomic images and x-, y-, and z-velocity images) was acquired. From these data, static measures of patellofemoral alignment and three-dimensional patellofemoral kinematics were derived. Single and multiple regressions between static and kinematic variables were evaluated. Although shown reliable, the static MRI measures could only partially predict patellofemoral kinematics, with r(2) -values ranging from 16% to 77%. This makes it imperitave that the current precise, accurate, 3D, dynamic imaging techniques be translated into clinical tools.

  14. Scapula Kinematics of Youth Baseball Players

    PubMed Central

    Oliver, Gretchen; Weimar, Wendi

    2015-01-01

    Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg), with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER) and maximum humeral internal rotation (MIR) during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly. PMID:26839605

  15. Dynamic control of kinematically redundant manipulators

    NASA Astrophysics Data System (ADS)

    Lin, Zhengcheng

    1993-03-01

    A robot manipulator is said to be kinematically redundant when it has more degrees of freedom than are necessary to accomplish a particular task. Useful control strategies are designed for kinematically redundant manipulators in order to enhance their performance. Following the impedance control approach, the problem of minimizing redundant manipulator collision impacts is addressed. The configuration control approach is used to reduce impulsive forces, while a simplified impedance control scheme is formulated to minimize rebound effects. A new Cartesian control strategy for redundant flexible-joint manipulators is proposed. The main idea in this hybrid scheme is to control not only the manipulator's end-effector but also its links, so as to achieve specified positions and velocities for the end-effector and the links. Finally, a new application of kinematically redundant manipulators is proposed: using redundancy resolution to compensate for joint flexibility. This redundancy resolution scheme is incorporated in a control strategy for redundant flexible-joint manipulators. The problem of possible algorithmic singularities is considered, and a scheme is suggested which makes the controller robust with respect to such singularities.

  16. New Kinematical Constraints on Cosmic Acceleration

    SciTech Connect

    Rapetti, David; Allen, Steve W.; Amin, Mustafa A.; Blandford, Roger; /-KIPAC, Menlo Park

    2007-05-25

    We present and employ a new kinematical approach to ''dark energy'' studies. We construct models in terms of the dimensionless second and third derivatives of the scale factor a(t) with respect to cosmic time t, namely the present-day value of the deceleration parameter q{sub 0} and the cosmic jerk parameter, j(t). An elegant feature of this parameterization is that all {Lambda}CDM models have j(t)=1 (constant), which facilitates simple tests for departures from the {Lambda}CDM paradigm. Applying our model to redshift-independent distance measurements, from type Ia supernovae and X-ray cluster gas mass fraction measurements, we obtain clear statistical evidence for a late time transition from a decelerating to an accelerating phase. For a flat model with constant jerk, j(t)=j, we measure q{sub 0}=-0.81 {+-} 0.14 and j=2.16 +0.81 -0.75, results that are consistent with {Lambda}CDM at about the 1{sigma} confidence level. In comparison to dynamical analyses, the kinematical approach uses a different model set and employs a minimum of prior information, being independent of any particular gravity theory. The results obtained with this new approach therefore provide important additional information and we argue that both kinematical and dynamical techniques should be employed in future dark energy studies, where possible.

  17. Scapula Kinematics of Youth Baseball Players.

    PubMed

    Oliver, Gretchen; Weimar, Wendi

    2015-12-22

    Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg), with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER) and maximum humeral internal rotation (MIR) during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly.

  18. Nature of Graphene Edges: A Review

    NASA Astrophysics Data System (ADS)

    Acik, Muge; Chabal, Yves J.

    2011-07-01

    Graphene edges determine the optical, magnetic, electrical, and electronic properties of graphene. In particular, termination, chemical functionalization and reconstruction of graphene edges leads to crucial changes in the properties of graphene, so control of the edges is critical to the development of applications in electronics, spintronics and optoelectronics. Up to date, significant advances in studying graphene edges have directed various smart ways of controlling the edge morphology. Though, it still remains as a major challenge since even minor deviations from the ideal shape of the edges significantly deteriorate the material properties. In this review, we discuss the fundamental edge configurations together with the role of various types of edge defects and their effects on graphene properties. Indeed, we highlight major demanding challenges to find the most suitable technique to characterize graphene edges for numerous device applications such as transistors, sensors, actuators, solar cells, light-emitting displays, and batteries in graphene technology.

  19. Investigation of the mica x-ray absorption near-edge structure spectral features at the Al K-edge

    NASA Astrophysics Data System (ADS)

    Wu, Ziyu; Marcelli, A.; Cibin, G.; Mottana, A.; Della Ventura, G.

    2003-10-01

    Near-edge features of Al x-ray absorption near-edge structure (XANES) spectra in aluminosilicate compounds with mixed coordination number are usually assigned to a fourfold coordinated site contribution followed by a sixfold coordinated site contribution that is displaced towards higher energy because of the increasing ligand nucleus potentials, neglecting possible contributions due to bond distance variations and local geometrical distortion. Here we present and discuss the Al K-edge XANES spectra of synthetic micas with either fourfold coordinated Al (phlogopite), or with sixfold coordinated Al (polylithionite), as well as with mixed coordination (preiswerkite). Multiple scattering simulations of XANES spectra demonstrate that octahedral contributions may overlap the tetrahedral ones so that the lower energy structures in mixed coordination compounds may be associated with the octahedral sites. This unexpected behaviour can be described as due to the effect of a significant reduction of the ligand field strength (i.e. large local distortion and Al-O bond distances).

  20. Pelvis and torso kinematics and their relationship to shoulder kinematics in high-school baseball pitchers.

    PubMed

    Oliver, Gretchen D; Keeley, David W

    2010-12-01

    It was the purpose of our study to examine the kinematics of the pelvis and torso and determine their relationship to the kinematics of the shoulder in high-school baseball pitchers. A single group, repeated-measures design was used to collect pelvis, torso, and shoulder kinematics throughout the pitching motion. Subjects threw a series of maximal effort fastballs to a catcher located the regulation distance (18.44m) from the pitching mound, and those data from the fastest pitch passing through the strike zone were analyzed. After test trials, kinematic data were analyzed using a series of descriptive statistics to identify outliers and determine the nature of the distribution before testing for the presence of relationships between the various parameters. Results indicated that for several parameters, the actions at and about the shoulder are strongly related to the actions of the pelvis and torso throughout the pitching motion. However, although pelvis and torso kinematics throughout the pitching motion were inversely related to both shoulder elevation and the plane of shoulder elevation, only the rate of axial torso rotation was significantly related to these shoulder parameters. More importantly, the rate of axial torso rotation is significantly related to these shoulder parameters in a way that may help explain the high rate of shoulder injury in high-school pitchers. Therefore, strength training should focus on developing a strong stable core including the gluteal musculature in an attempt to control the rate of torso rotation during the pitch.

  1. Computational tool for comparison of kinematic mechanisms and commonly used kinematic models

    SciTech Connect

    Hollerbach, K.; Hollister, A.M.; Van Vorhis, R.L.

    1997-03-01

    Accurate, reliable, and reproducible methods to measure the movements of human joints have been elusive. Currently, three-dimensional recording methods are used to track the motion of one segment relative to another as the joint moves. Six parameters describe the moving segment`s location and orientation relative to the reference segment: three translations (x, y, and z) and three rotations (yaw, pitch and roll) in the reference frame. The raw data can be difficult to interpret. For this reason, several methods have been developed to measure the motion of human joints and to describe the resulting data. For example, instant helical axes or screw deviation axes (Kinzell et al., 1972), the Joint Coordinate System of Grood and Suntay (1983), and the Euler angle method have been used to describe the movements of bones relative to each other. None of these methods takes into account the physical kinematic mechanism producing the joint motion. More recently, Lupichuk (1995) has developed an algorithm to find, for an arbitrary revolute, the axis` position and orientation in three- dimensional space. Each of these methods has advantages and disadvantages in analyzing joint kinematics. The authors have developed software to provide a means of comparing these methods for arbitrary, single degree of freedom, kinematic mechanisms. Our objective is to demonstrate the software and to show how it can be used to compare the results from the different kinematic models as they are applied to specific kinematic mechanisms.

  2. The SAMI Galaxy Survey: Revisiting Galaxy Classification through High-order Stellar Kinematics

    NASA Astrophysics Data System (ADS)

    van de Sande, Jesse; Bland-Hawthorn, Joss; Fogarty, Lisa M. R.; Cortese, Luca; d’Eugenio, Francesco; Croom, Scott M.; Scott, Nicholas; Allen, James T.; Brough, Sarah; Bryant, Julia J.; Cecil, Gerald; Colless, Matthew; Couch, Warrick J.; Davies, Roger; Elahi, Pascal J.; Foster, Caroline; Goldstein, Gregory; Goodwin, Michael; Groves, Brent; Ho, I.-Ting; Jeong, Hyunjin; Jones, D. Heath; Konstantopoulos, Iraklis S.; Lawrence, Jon S.; Leslie, Sarah K.; López-Sánchez, Ángel R.; McDermid, Richard M.; McElroy, Rebecca; Medling, Anne M.; Oh, Sree; Owers, Matt S.; Richards, Samuel N.; Schaefer, Adam L.; Sharp, Rob; Sweet, Sarah M.; Taranu, Dan; Tonini, Chiara; Walcher, C. Jakob; Yi, Sukyoung K.

    2017-01-01

    Recent cosmological hydrodynamical simulations suggest that integral field spectroscopy can connect the high-order stellar kinematic moments h3 (∼skewness) and h4 (∼kurtosis) in galaxies to their cosmological assembly history. Here, we assess these results by measuring the stellar kinematics on a sample of 315 galaxies, without a morphological selection, using two-dimensional integral field data from the SAMI Galaxy Survey. Proxies for the spin parameter ({λ }{R{{e}}}) and ellipticity ({ε }{{e}}) are used to separate fast and slow rotators; there exists a good correspondence to regular and non-regular rotators, respectively, as also seen in earlier studies. We confirm that regular rotators show a strong h3 versus V/σ anti-correlation, whereas quasi-regular and non-regular rotators show a more vertical relation in h3 and V/σ . Motivated by recent cosmological simulations, we develop an alternative approach to kinematically classify galaxies from their individual h3 versus V/σ signatures. Within the SAMI Galaxy Survey, we identify five classes of high-order stellar kinematic signatures using Gaussian mixture models. Class 1 corresponds to slow rotators, whereas Classes 2–5 correspond to fast rotators. We find that galaxies with similar {λ }{R{{e}}}{--}{ε }{{e}} values can show distinctly different {h}3{--}V/σ signatures. Class 5 objects are previously unidentified fast rotators that show a weak h3 versus V/σ anti-correlation. From simulations, these objects are predicted to be disk-less galaxies formed by gas-poor mergers. From morphological examination, however, there is evidence for large stellar disks. Instead, Class 5 objects are more likely disturbed galaxies, have counter-rotating bulges, or bars in edge-on galaxies. Finally, we interpret the strong anti-correlation in h3 versus V/σ as evidence for disks in most fast rotators, suggesting a dearth of gas-poor mergers among fast rotators.

  3. Structure and kinematics of the Sumatran Fault System in North Sumatra (Indonesia)

    NASA Astrophysics Data System (ADS)

    Fernández-Blanco, David; Philippon, Melody; von Hagke, Christoph

    2016-12-01

    Lithospheric-scale faults related to oblique subduction are responsible for some of the most hazardous earthquakes reported worldwide. The mega-thrust in the Sunda sector of the Sumatran oblique subduction has been intensively studied, especially after the infamous 2004 Mw 9.1 earthquake, but its onshore kinematic complement within the Sumatran subduction, the transform Sumatran Fault System, has received considerably less attention. In this paper, we apply a combination of analysis of Digital Elevation Models (ASTER GDEM) and field evidence to resolve the kinematics of the leading edge of deformation of the northern sector of the Sumatran Fault System. To this end, we mapped the northernmost tip of Sumatra, including the islands to the northwest, between 4.5°N and 6°N. Here, major topographic highs are related to different faults. Using field evidence and our GDEM structural mapping, we can show that in the area where the fault bifurcates into two fault strands, two independent kinematic regimes evolve, both consistent with the large-scale framework of the Sumatran Fault System. Whereas the eastern branch is a classic Riedel system, the western branch features a fold-and-thrust belt. The latter contractional feature accommodated significant amounts (c. 20%) of shortening of the system in the study area. Our field observations of the tip of the NSFS match a strain pattern with a western contractional domain (Pulau Weh thrust splay) and an eastern extensional domain (Pulau Aceh Riedel system), which are together characteristic of the tip of a propagating strike-slip fault, from a mechanical viewpoint. For the first time, we describe the strain partitioning resulting from the propagation of the NSFS in Sumatra mainland. Our study helps understanding complex kinematics of an evolving strike-slip system, and stresses the importance of field studies in addition to remote sensing and geophysical studies.

  4. Ultrafast Dynamics near the M-edge in Chromium

    NASA Astrophysics Data System (ADS)

    McFarland, Brian; Zhu, Jian-Xin; Prasankumar, Rohit; Rodriguez, George; Sandberg, Richard; Taylor, Antoinette; Yarotski, Dmitry

    2015-03-01

    The exploration of element specific ultrafast spin dynamics in transition metals has been extended by recent advances in table top VUV sources based on high harmonic generation. These sources provide femtosecond time resolution at photon energies that span the magnetism sensitive 3p to 3d band absorption (M-edge) in these materials. The time scale of spin dynamics determines the fundamental limits of magnetic data recording and gives insight into magnetoelectric coupling mechanisms in complex functional materials. Though there have been multiple time-resolved studies on ferromagnetic systems, antiferromagnetic (AFM) dynamics remains largely unexplored. As an AFM test system we choose chromium and measure transient reflectivity for photon energies spanning the chromium M-edge. Picosecond dynamics are measured throughout the spectrum of the VUV probe beam after excitation by an IR laser pulse. A dramatic difference is observed in the transient magnetic linear absorption dichroism of chromium for photon energies above and below the M-edge (~ 46 eV) as temperature is varied through the AFM transition. While a decrease in reflectivity is seen below the M-edge we find an increase in reflectivity above the edge. We attribute this variation to interplay between electronic and magnetic responses and discuss its relation to ultrafast magnetic ordering dynamics.

  5. Oscillations of a Turbulent Jet Incident Upon an Edge

    SciTech Connect

    J.C. Lin; D. Rockwell

    2000-09-19

    For the case of a jet originating from a fully turbulent channel flow and impinging upon a sharp edge, the possible onset and nature of coherent oscillations has remained unexplored. In this investigation, high-image-density particle image velocimetry and surface pressure measurements are employed to determine the instantaneous, whole-field characteristics of the turbulent jet-edge interaction in relation to the loading of the edge. It is demonstrated that even in absence of acoustic resonant or fluid-elastic effects, highly coherent, self-sustained oscillations rapidly emerge above the turbulent background. Two clearly identifiable modes of instability are evident. These modes involve large-scale vortices that are phase-locked to the gross undulations of the jet and its interaction with the edge, and small-scale vortices, which are not phase-locked. Time-resolved imaging of instantaneous vorticity and velocity reveals the form, orientation, and strength of the large-scale concentrations of vorticity approaching the edge in relation to rapid agglomeration of small-scale vorticity concentrations. Such vorticity field-edge interactions exhibit rich complexity, relative to the simplified pattern of vortex-edge interaction traditionally employed for the quasi-laminar edgetone. Furthermore, these interactions yield highly nonlinear surface pressure signatures. The origin of this nonlinearity, involving coexistence of multiple frequency components, is interpreted in terms of large- and small-scale vortices embedded in distributed vorticity layers at the edge. Eruption of the surface boundary layer on the edge due to passage of the large-scale vortex does not occur; rather apparent secondary vorticity concentrations are simply due to distension of the oppositely-signed vorticity layer at the tip of the edge. The ensemble-averaged turbulent statistics of the jet quickly take on an identity that is distinct from the statistics of the turbulent boundary layer in the channel

  6. Electronic Bandgap and Edge Reconstruction in Phosphorene: An Experimental/Theoretical joint investigation

    NASA Astrophysics Data System (ADS)

    Liang, Liangbo; Wang, Jun; Lin, Wenzhi; Sumpter, Bobby G.; Pan, Minghu; Meunier, Vincent

    2015-03-01

    Phosphorene, or monolayer black phosphorus, is a new 2D layered material with high hole mobility and direct semiconducting bandgap. However, the direct bandgap of phosphorene has not been directly measured, and the properties of its edges have not been considered in detail. In a joint experimental/theoretical work, we studied the electronic properties of phosphorene and its edges [Liang et al., Nano Letters, 2014, 14, 6400]. A detailed scanning tunneling microscopy/spectroscopy (STM/S) study with first-principles calculations reveals the presence of a semiconducting 2 eV gap, the direct bandgap for phosphorene. More importantly, we were able to identify a sharp mono-step in phosphorene that allowed us to perform the first-ever investigation of edges. STS measurements across the step edge indicate nontrivial multiple edge states located inside the 2 eV gap and below the Fermi level. To understand these edge states, we have modeled a series of 1D phosphorene nanoribbons including armchair- and zigzag-edged PNRs. Extensive density functional theory calculations show that edge reconstructions are responsible for energy positions of these edge states. The reconstructions self-passivate most edge dangling bonds by switching the coordination number of phosphorus from 3 to 4 or 5. NYSTAR Program C080117 and the Office of Naval Research; Oak Ridge National Laboratory by U.S. Department of Energy.

  7. Quantifying edge significance on maintaining global connectivity

    PubMed Central

    Qian, Yuhua; Li, Yebin; Zhang, Min; Ma, Guoshuai; Lu, Furong

    2017-01-01

    Global connectivity is a quite important issue for networks. The failures of some key edges may lead to breakdown of the whole system. How to find them will provide a better understanding on system robustness. Based on topological information, we propose an approach named LE (link entropy) to quantify the edge significance on maintaining global connectivity. Then we compare the LE with the other six acknowledged indices on the edge significance: the edge betweenness centrality, degree product, bridgeness, diffusion importance, topological overlap and k-path edge centrality. Experimental results show that the LE approach outperforms in quantifying edge significance on maintaining global connectivity. PMID:28349923

  8. Saddle-node dynamics for edge detection

    SciTech Connect

    Wong, Y.F.

    1994-09-01

    The author demonstrates how the formulation of a nonlinear scale-space filter can be used for edge detection and junction analysis. By casting edge-preserving filtering in terms of maximizing information content subject to an average cost function, the computed cost at each pixel location becomes a local measure of edgeness. This computation depends on a single scale parameter and the given image data. Unlike previous approaches which require careful tuning of the filter kernels for various types of edges, this scheme is general enough to be able to handle different edges, such as lines, step edges, corners and junctions. Anisotropy in the data is handled automatically by the nonlinear dynamics.

  9. Window Spacers and Edge Seals in Insulating Glass Units: A State-of-the-Art Review and Future Perspectives

    SciTech Connect

    SINTEF Building and Infrastructure; Norwegian University of Science and Technology; Bergh, Sofie Van Den; Hart, Robert; Jelle, Bjrn Petter; Gustavsen, Arild

    2013-01-31

    Insulating glass (IG) units typically consist of multiple glass panes that are sealed and held together structurally along their perimeters. This report describes a study of edge seals in IG units. First, we summarize the components, requirements, and desired properties of edge construction in IG units, based on a survey of the available literature. Second, we review commercially available window edge seals and describe their properties, to provide an easily accessible reference for research and commercial purposes. Finally, based on the literature survey and review of current commercial edge seal systems, we identify research opportunities for future edge seal improvements and solutions.

  10. Galactic kinematics from a sample of young massive stars

    NASA Astrophysics Data System (ADS)

    Bobylev, V. V.; Bajkova, A. T.

    2013-08-01

    Based on published sources, we have created a kinematic database on 220 massive (> 10 M ⊙) young Galactic star systems located within ≤3 kpc of the Sun. Out of them, ≈100 objects are spectroscopic binary and multiple star systems whose components are massive OB stars; the remaining objects are massive Hipparcos B stars with parallax errors of no more than 10%. Based on the entire sample, we have constructed the Galactic rotation curve, determined the circular rotation velocity of the solar neighborhood around the Galactic center at R 0 = 8kpc, V 0 = 259±16 km s-1, and obtained the following spiral density wave parameters: the amplitudes of the radial and azimuthal velocity perturbations f R = -10.8 ± 1.2 km s-1 and f θ = 7.9 ± 1.3 km s-1, respectively; the pitch angle for a two-armed spiral pattern i = -6.0° ± 0.4°, with the wavelength of the spiral density wave near the Sun being λ = 2.6 ± 0.2 kpc; and the radial phase of the Sun in χ ⊙ = -120° ± 4°. We show that such peculiarities of the Gould Belt as the local expansion of the system, the velocity ellipsoid vertex deviation, and the significant additional rotation can be explained in terms of the density wave theory. All these effects decrease noticeably once the influence of the spiral density wave on the velocities of nearby stars has been taken into account. The influence of Gould Belt stars on the Galactic parameter estimates has also been revealed. Eliminating them from the kinematic equations has led to the following new values of the spiral density wave parameters: f θ = 2.9 ± 2.1 km s-1 and χ ⊙ = -104° ± 6°.

  11. Feature Extraction Without Edge Detection

    DTIC Science & Technology

    1993-09-01

    feature? A.I. Memo 1356, MIT Artificial Intellegence Lab, April 1992. [65] W. A. Richards, B. Dawson, and D. Whittington. Encoding contour shape by...AD-A279 842 . " Technical Report 1434 --Feature Extraction Without Edge Detection Ronald D. Chane MIT Artificial .Intelligencc Laboratory ",, 𔃾•d...Chaney 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER Massachusetts Institute of Technology Artificial

  12. Etching Of Semiconductor Wafer Edges

    DOEpatents

    Kardauskas, Michael J.; Piwczyk, Bernhard P.

    2003-12-09

    A novel method of etching a plurality of semiconductor wafers is provided which comprises assembling said plurality of wafers in a stack, and subjecting said stack of wafers to dry etching using a relatively high density plasma which is produced at atmospheric pressure. The plasma is focused magnetically and said stack is rotated so as to expose successive edge portions of said wafers to said plasma.

  13. Retention and the competitive edge.

    PubMed

    Lemery, L D

    2000-01-01

    I believe that retaining effective, seasoned employees enhances an organization's ability to compete in the marketplace. Though these seasoned employees seem to be more explicitly expensive, a detailed analysis of the costs involved in hiring and orienting replacement personnel may prove this assumption false. In addition, seasoned employees' intimate job knowledge actually constitutes the organization's competitive edge. Therefore, retaining seasoned personnel seems to become an important, mission- and vision-imperative institutional objective.

  14. Topological edge states in pnictides

    NASA Astrophysics Data System (ADS)

    Youmans, Cody; Ghaemi, Pouyan; Kargarian, Mehdi

    In some members of the ferro-pnictides, non-trivial topology in the bulk band-structure is related to potentially observable gapless edge states. We study these states numerically and analytically for a range of parameters, with and without superconductivity and antiferromagnetic SDW ordering, and their relation to the symmetries and topologically non-trivial aspects of our model Hamiltonian. Support was provided by the Doctoral Student Research Grant program at the Graduate Center, CUNY.

  15. Kinematic History and Tectonic Evolution of the Amerasian Basin: Investigating Palaeo-Plate Boundaries around the Chukchi Borderlands

    NASA Astrophysics Data System (ADS)

    Brumley, K.; Coakley, B.; Stone, D.; Wallace, W.

    2007-12-01

    The multi-stage opening of the Arctic Ocean's Amerasian Basin is only partially understood due to the difficulty of utilizing traditional marine geologic and geophysical techniques in ice-covered waters. While the kinematic development of the Eurasian Basin is well-understood to be the northernmost extension of the Mid-Atlantic Ridge, the history of the morphologically complex Amerasian Basin may be due to multiple events, significantly complicating interpretation of its history. Any detailed model for the opening of the Amerasian Basin must both incorporate structures that accommodate spreading as well as explain the tectonic mechanisms that drove basin development. Cretaceous-age tholeiitic flood basalts and associated radiating dike swarms of the High Arctic Large Igneous Province (HALIP), found along the basin margin, provide a tectonic mechanism and geometry to substantiate sound reconstruction. Detailed models need also consider pre-existing zones of weakness such as the deformation front of the Devonian Caledonides, which may underlie Barents Shelf sediments (Gee and Bogolepova, 2003). Reactivation of these ancient structural trends along this suture zone may explain the motion of Mendeleev Ridge as it rifted from Lomonosov Ridge and created the rectangular pull-apart basin between them. We propose a revised plate model for the development of the Amerasian Basin. A Cretaceous magmatic source localized under the Alpha Ridge accompanied the onset of rifting. This generated the HALIP radiating dike swarms and tholeiitic flood basalts found on the DeLong Islands, Svalbard, Franz Joseph Land, Greenland, Sverdrup Basin and, possibly, the Alpha and Mendeleev Ridges. New bathymetric and sub-bottom profiling data also suggests the existence of igneous dikes on Chukchi Cap. The subsequent development of a triple junction resulted in dilational opening of the Canada Basin. Spreading was accommodated by the migration of the southern edges of the northeastern Siberian

  16. Whole limb kinematics are preferentially conserved over individual joint kinematics after peripheral nerve injury.

    PubMed

    Chang, Young-Hui; Auyang, Arick G; Scholz, John P; Nichols, T Richard

    2009-11-01

    Biomechanics and neurophysiology studies suggest whole limb function to be an important locomotor control parameter. Inverted pendulum and mass-spring models greatly reduce the complexity of the legs and predict the dynamics of locomotion, but do not address how numerous limb elements are coordinated to achieve such simple behavior. As a first step, we hypothesized whole limb kinematics were of primary importance and would be preferentially conserved over individual joint kinematics after neuromuscular injury. We used a well-established peripheral nerve injury model of cat ankle extensor muscles to generate two experimental injury groups with a predictable time course of temporary paralysis followed by complete muscle self-reinnervation. Mean trajectories of individual joint kinematics were altered as a result of deficits after injury. By contrast, mean trajectories of limb orientation and limb length remained largely invariant across all animals, even with paralyzed ankle extensor muscles, suggesting changes in mean joint angles were coordinated as part of a long-term compensation strategy to minimize change in whole limb kinematics. Furthermore, at each measurement stage (pre-injury, paralytic and self-reinnervated) step-by-step variance of individual joint kinematics was always significantly greater than that of limb orientation. Our results suggest joint angle combinations are coordinated and selected to stabilize whole limb kinematics against short-term natural step-by-step deviations as well as long-term, pathological deviations created by injury. This may represent a fundamental compensation principle allowing animals to adapt to changing conditions with minimal effect on overall locomotor function.

  17. Multibody kinematics optimization with marker projection improves the accuracy of the humerus rotational kinematics.

    PubMed

    Begon, Mickaël; Bélaise, Colombe; Naaim, Alexandre; Lundberg, Arne; Chèze, Laurence

    2016-10-20

    Markers put on the arm undergo large soft tissue artefact (STA). Using markers on the forearm, multibody kinematics optimization (MKO) helps improve the accuracy of the arm kinematics especially its longitudinal rotation. However deleterious effect of STA may persist and affect other segment estimate. The objective was to present an innovative multibody kinematics optimization algorithm with projection of markers onto a requested axis of the local system of coordinates, to cancel their deleterious effect on this degree-of-freedom. Four subjects equipped with markers put on intracortical pins inserted into the humerus, on skin (scapula, arm and forearm) and subsequently on rigid cuffs (arm and forearm) performed analytic, daily-living, sports and range-of-motion tasks. Scapulohumeral kinematics was estimated using 1) pin markers (reference), 2) single-body optimization, 3) MKO, 4) MKO with projection of all arm markers and 5) MKO with projection of a selection of arm markers. Approaches 2-4 were applied to markers put on the skin and the cuff. The main findings were that multibody kinematics optimization improved the accuracy of 40-50% and the projection algorithm added an extra 20% when applied to cuff markers or a selection of skin markers (all but the medial epicondyle). Therefore, the projection algorithm performed better than multibody and single-body optimizations, especially when using markers put on a cuff. Error of humerus orientation was reduced by half to finally be less than 5°. To conclude, this innovative algorithm is a promising approach for estimating accurate upper-limb kinematics.

  18. On the Connection Between Flap Side-Edge Noise and Tip Vortex Dynamics

    NASA Technical Reports Server (NTRS)

    Casalino, D.; Hazir, A.; Fares, E.; Duda, B.; Khorrami, M. R.

    2015-01-01

    The goal of the present work is to investigate how the dynamics of the vortical flow about the flap side edge of an aircraft determine the acoustic radiation. A validated lattice- Boltzmann CFD solution of the unsteady flow about a detailed business jet configuration in approach conditions is used for the present analysis. Evidence of the connection between the noise generated by several segments of the inboard flap tip and the aerodynamic forces acting on the same segments is given, proving that the noise generation mechanism has a spatially coherent and acoustically compact character on the scale of the flap chord, and that the edge-scattering effects are of secondary importance. Subsequently, evidence of the connection between the kinematics of the tip vortex system and the aerodynamic force is provided. The kinematics of the dual vortex system are investigated via a core detection technique. Emphasis is placed on the mutual induction effects between the two main vortices rolling up from the pressure and suction sides of the flap edge. A simple heuristic formula that relates the far-field noise spectrum and the cross-spectrum of the unsteady vortical positions is developed.

  19. Aluminium K-Edge XANES Study of Mica Preiswerkite

    SciTech Connect

    Wu, Z.; Marcelli, A.; Cibin, G.; Mottana, A.; Della Ventura, G.; /SLAC, SSRl

    2006-10-27

    We present the Al K-edge XANES spectrum of synthetic mica with mixed fourfold coordinated and sixfold coordinated Al (preiswerkite). Experimental analysis and multiple scattering simulations of XANES spectra demonstrate that octahedral contributions may overlap the tetrahedral ones so that the lower energy structures in mixed coordination compounds may be associated to Al octahedral site. This unexpected behavior can be explained as due to a large local distortion of the Al octahedral site.

  20. Knife-edge seal for vacuum bagging

    NASA Technical Reports Server (NTRS)

    Rauschl, J. A.

    1980-01-01

    Cam actuated clamps pinch bagging material between long knife edge (mounted to clamps) and high temperature rubber cushion bonded to baseplate. No adhesive, tape, or sealing groove is needed to seal edge of bagging sheet against base plate.

  1. Edge and coupled core/edge transport modeling in tokamak

    SciTech Connect

    Pearlstein, L D; Casper, T A; Cohen, R H; LoDestro, L L; Mattor, N; Porter, G D; Rensink, M E; Rognlien, T D; Ryutov, D D; Scott, H A; Wan, A

    1998-10-14

    Recent advances in the theory and modelling of tokamak edge, scrape-off-layer and divertor plasmas are described. The effects of the poloidal ExB drift on inner/outer divertor-plate asymmetries within a 1D analysis are shown to be in good agreement with experimental observations; above a critical v ExB, the model predicts transitions to supersonic SOL flow at the inboard midplane. Two-dimensional simulations show the importance of ExB flow in the private-flux region and B-drift effects. A theory of rough plasma-facing surfaces is given, and interesting effects, some traveling back up the magnetic field-lines to the SOL plasma, are predicted. The parametric dependence of detached-plasma states in slab geometry has been explored; with sufficient pumping, the location of the ionization front can be controlled; otherwise only fronts at the plate or the X-point are stable. Studies with a more accurate Monte-Carlo neutrals model and a detailed non-LTE radiation-transport code indicate various effects are important for quantitative rnodelling. Long-lived oscillatory UEDGE solutions in both ITER and DIII-D are reported. Detailed simulations of the DIII-D core and edge are presented; impurity and plasma flow are shown to be well modelled with UEDGE, and the roles of impurity and neutral transport in the edge and SOL are discussed.

  2. Lower limb kinematic variability in dancers performing drop landings onto floor surfaces with varied mechanical properties.

    PubMed

    Reeve, Helen K; Hopper, Luke S; Elliott, Bruce C; Ackland, Timothy R

    2013-08-01

    Elite dancers perform highly skilled and consistent movements. These movements require effective regulation of the intrinsic and extrinsic forces acting within and on the body. Customized, compliant floors typically used in dance are assumed to enhance dance performance and reduce injury risk by dampening ground reaction forces during tasks such as landings. As floor compliance can affect the extrinsic forces applied to the body, secondary effects of floor properties may be observed in the movement consistency or kinematic variability exhibited during dance performance. The aim of this study was to investigate the effects of floor mechanical properties on lower extremity kinematic variability in dancers performing landing tasks. A vector coding technique was used to analyze sagittal plane knee and ankle joint kinematic variability, in a cohort of 12 pre-professional dancers, through discrete phases of drop landings from a height of 0.2m. No effect on kinematic variability was observed between floors, indicating that dancers could accommodate the changing extrinsic floor conditions. Future research may consider repeat analysis under more dynamic task constraints with a less experienced cohort. However, knee/ankle joint kinematic variability was observed to increase late in the landing phase which was predominantly comprised of knee flexion coupled with the terminal range of ankle dorsiflexion. These findings may be the result of greater neural input late in the landing phase as opposed to the suggested passive mechanical interaction of the foot and ankle complex at initial contact with a floor. Analysis of joint coordination in discrete movement phases may be of benefit in identifying intrinsic sources of variability in dynamic tasks that involve multiple movement phases.

  3. Kinematic Structures Description of Bionic Hand Based on VF Set

    NASA Astrophysics Data System (ADS)

    Liu, Xiancan; Bai, Pengying; Luo, Min; Gao, Meng; Zhan, Qiang

    2017-03-01

    This paper presents a method for describing kinematic structure of bionic hand based on VF (virtual finger) set. At first, a 20 DOFs (degrees of freedom) human hand kinematic model is built, which is expressed by five fingers’ kinematic chains consisting of kinematic pairs and symbols that represent geometric relationships of kinematic pairs’ axes. Based on the concept of VF, the hand fingers are divided into two types: VFAA having adduction/abduction motion and VFFE having flexion/extension motion. The concept of VF set comprising VFAAs and VFFEs is defined, human hand and six basic grasp postures are described by VF set. Then, the structures corresponding VFAA and VFFE are given according to active and passive forms of finger joints, and VFFE Structure-Base comprising 20 conventional structures is built. Based on VF set and the structures of VFAA and VFFE, VF sets and kinematic structures of several classic bionic hands are given.

  4. Reduction of Free-Edge Stress Concentration

    DTIC Science & Technology

    1985-01-01

    oscillatory type of behavior near the free edge of the capped laminate before converging to zero further inside the laminate. The length of the edge effect is...Condition," J. Comp. Materials. Vol. 14 (1980), p. 2. 13. Altus, E., Rotem, A. and Shmueli, M., "Free Edge Effect in Angle- Ply Laminates - A New

  5. Understanding and preventing the edge effect.

    PubMed

    Cheneau, Edouard; Wolfram, Roswitha; Leborgne, Laurent; Waksman, Ron

    2003-02-01

    Edge stenosis, combining neointimal proliferation and negative remodeling, remains a serious limitation of vascular brachytherapy. This review comprehensively presents terminology, definitions, mechanisms, and treatment strategies to better understand the complexities of edge narrowing. The major contributors to this phenomenon are known; understanding the practical solutions will enable us to further minimize the problem of the edge effect.

  6. Densified edge seals for fuel cell components

    DOEpatents

    DeCasperis, Anthony J.; Roethlein, Richard J.; Breault, Richard D.

    1982-01-01

    A porous fuel cell component, such as an electrode substrate, has a densified edge which forms an improved gas seal during operation when soaked with electrolyte. The edges are made from the same composition as the rest of the component and are made by compressing an increased thickness of this material along the edges during the fabrication process.

  7. Kinematics of transition during human accelerated sprinting

    PubMed Central

    Nagahara, Ryu; Matsubayashi, Takeo; Matsuo, Akifumi; Zushi, Koji

    2014-01-01

    ABSTRACT This study investigated kinematics of human accelerated sprinting through 50 m and examined whether there is transition and changes in acceleration strategies during the entire acceleration phase. Twelve male sprinters performed a 60-m sprint, during which step-to-step kinematics were captured using 60 infrared cameras. To detect the transition during the acceleration phase, the mean height of the whole-body centre of gravity (CG) during the support phase was adopted as a measure. Detection methods found two transitions during the entire acceleration phase of maximal sprinting, and the acceleration phase could thus be divided into initial, middle, and final sections. Discriminable kinematic changes were found when the sprinters crossed the detected first transition—the foot contacting the ground in front of the CG, the knee-joint starting to flex during the support phase, terminating an increase in step frequency—and second transition—the termination of changes in body postures and the start of a slight decrease in the intensity of hip-joint movements, thus validating the employed methods. In each acceleration section, different contributions of lower-extremity segments to increase in the CG forward velocity—thigh and shank for the initial section, thigh, shank, and foot for the middle section, shank and foot for the final section—were verified, establishing different acceleration strategies during the entire acceleration phase. In conclusion, there are presumably two transitions during human maximal accelerated sprinting that divide the entire acceleration phase into three sections, and different acceleration strategies represented by the contributions of the segments for running speed are employed. PMID:24996923

  8. Structure and kinematics of molecular jets

    NASA Astrophysics Data System (ADS)

    Snell, R. L.

    1986-04-01

    Observational studies of the structure and kinematics of the supersonic molecular gas in star-forming regions are reviewed. These studies have suggested that the bulk of the high-velocity gas may be ambient-cloud material swept up by a collimated stellar wind. The actual structures of these outflows, however, are poorly understood. One source that may provide a better understanding of molecular outflows is that in the nearby dark cloud LDN 1551. New observations of this outflow are presented and discussed in context of the models proposed by Snell and Schloerb.

  9. Confined kinematics of suspended rigid fibres

    NASA Astrophysics Data System (ADS)

    Scheuer, A.; Perez, M.; Abisset-Chavanne, E.; Chinesta, F.; Keunings, R.

    2016-10-01

    We address the extension of Jeffery's model, governing the orientation of rods immersed in a Newtonian fluid, to confined regimes occurring when the thickness of the flow domain is narrower than the rod length. The main modelling ingredients concern: (i) the consideration of the rod interactions with one or both gap walls and their effects on the rod orientation kinematics; (ii) the consideration of non-uniform strain rates at the scale of the rod, requiring higher-order descriptions. Such scenarios are very close to those encountered in real composites forming processes and have never been appropriately addressed from a microstructural point of view.

  10. Quantum simulation of noncausal kinematic transformations.

    PubMed

    Alvarez-Rodriguez, U; Casanova, J; Lamata, L; Solano, E

    2013-08-30

    We propose the implementation of Galileo group symmetry operations or, in general, linear coordinate transformations in a quantum simulator. With an appropriate encoding, unitary gates applied to our quantum system give rise to Galilean boosts or spatial and time parity operations in the simulated dynamics. This framework provides us with a flexible toolbox that enhances the versatility of quantum simulation theory, allowing the direct access to dynamical quantities that would otherwise require full tomography. Furthermore, this method enables the study of noncausal kinematics and phenomena beyond special relativity in a quantum controllable system.

  11. Cosmological Applications of the Gaussian Kinematic Formula

    NASA Astrophysics Data System (ADS)

    Fantaye, Yabebal T.; Marinucci, Domenico

    2014-05-01

    The Gaussian Kinematic Formula (GKF, see Adler and Taylor (2007,2011)) is an extremely powerful tool allowing for explicit analytic predictions of expected values of Minkowski functionals under realistic experimental conditions for cosmological data collections. In this paper, we implement Minkowski functionals on multipoles and needlet components of CMB fields, thus allowing a better control of cosmic variance and extraction of information on both harmonic and real domains; we then exploit the GKF to provide their expected values on spherical maps, in the presence of arbitrary sky masks, and under nonGaussian circumstances.

  12. Mapping Dark Matter Halos with Stellar Kinematics

    NASA Astrophysics Data System (ADS)

    Murphy, Jeremy; Gebhardt, K.; Greene, J. E.; Graves, G.

    2013-07-01

    Galaxies of all sizes form and evolve in the centers of dark matter halos. As these halos constitute the large majority of the total mass of a galaxy, dark matter certainly plays a central role in the galaxy's formation and evolution. Yet despite our understanding of the importance of dark matter, observations of the extent and shape of dark matter halos have been slow in coming. The paucity of data is particularly acute in elliptical galaxies. Happily, concerted effort over the past several years by a number of groups has been shedding light on the dark matter halos around galaxies over a wide range in mass. The development of new instrumentation and large surveys, coupled with the tantalizing evidence for a direct detection of dark matter from the AMS experiment, has brought on a golden age in the study of galactic scale dark matter halos. I report on results using extended stellar kinematics from integrated light to dynamically model massive elliptical galaxies in the local universe. I use the integral field power of the Mitchell Spectrograph to explore the kinematics of stars to large radii (R > 2.5 r_e). Once the line-of-sight stellar kinematics are measured, I employ orbit-based, axisymmetric dynamical modeling to explore a range of dark matter halo parameterizations. Globular cluster kinematics at even larger radii are used to further constrain the dynamical models. The dynamical models also return information on the anisotropy of the stars which help to further illuminate the primary formation mechanisms of the galaxy. Specifically, I will show dynamical modeling results for the first and second rank galaxies in the Virgo Cluster, M49 and M87. Although similar in total luminosity and ellipticity, these two galaxies show evidence for different dark matter halo shapes, baryon to dark matter fractions, and stellar anisotropy profiles. Moreover, the stellar velocity dispersion at large radii in M87 is significantly higher than the globular clusters at the same

  13. Kinematics of Low Surface Brightness Galaxies

    NASA Astrophysics Data System (ADS)

    Cardullo, A.; Pizzella, A.; Corsini, E. M.; Bertola, F.

    2008-10-01

    We analyzed the kinematic of 12 low surface-brightness (LSB) galaxies to study the correlation between the disk circular velocity V_{c} and the central velocity dispersion of the spheroidal component σ_{0}. This relation has been claimed to be either the same power-law relation tep{buy} or a different linear one tep{piz} with respect to high surface-brightness (HSB) galaxies. We confirm here that LSB and HSB galaxies follow two different linear V_{c}-σ_{0} relations.

  14. Stellar population and kinematics of NGC 404

    NASA Astrophysics Data System (ADS)

    Bouchard, A.; Prugniel, P.; Koleva, M.; Sharina, M.

    2010-04-01

    Context. NGC 404 is a nearly face-on, nearby low-luminosity lenticular galaxy. Probing its characteristics provides a wealth of information on the details of the possible evolution processes of dS0 galaxies, which may not be possible in other, more distant objects. Aims: We study the internal kinematics and the spatial distribution of the star formation history in NGC 404. Methods: We obtained long-slit spectroscopy at the OHP 1m93 telescope along the major and minor axes of NGC 404. The spectra had a resolution R = 3600 covering a wavelength range from 4600 to 5500 Å. The data were fitted against the Pegase. HR stellar population models to derive the internal stellar kinematics, ages, and metallicities simultaneously. All this was done while taking any instrumental contamination to the line-of-sight velocity distribution into account. First, the global properties of the galaxy were analysed by fitting a single model to the data and looking at the kinematic variations and SSP equivalent age and metallicities as a function of radius. Afterwards, the stellar populations were decomposed into 4 individually analysed components. Results: NGC 404 clearly shows two radial velocity inversions along its major axis. The kinematically decoupled core rotates in the same direction as the neutral hydrogen shell that surrounds the galaxy. We resolved the star formation history in the core of the galaxy into 4 events: a very young (< 150 Myr, and [Fe/H] = 0.4) component with constant ongoing star formation, a second young (430 Myr) component with [Fe/H] = 0.1, an intermediate population (1.7 Gyr) that has [Fe/H] = -0.05, and finally an old (12 Gyr) component with [Fe/H] = -1.26. The two young components fade very quickly with radius, leaving only the intermediate and old population at a radius of 25´´ (370 pc) from the centre. Conclusions: We conclude that NGC 404 had a spiral morphology about 1 Gyr ago and that one or many merger events has triggered a morphological transition

  15. Kinematics and Fluid Dynamics of Jellyfish Maneuvering

    NASA Astrophysics Data System (ADS)

    Miller, Laura; Hoover, Alex

    2014-11-01

    Jellyfish propel themselves through the water through periodic contractions of their elastic bells. Some jellyfish, such as the moon jellyfish Aurelia aurita and the upside down jellyfish Cassiopea xamachana, can perform turns via asymmetric contractions of the bell. The fluid dynamics of jellyfish forward propulsion and turning is explored here by analyzing the contraction kinematics of several species and using flow visualization to quantify the resulting flow fields. The asymmetric contraction and structure of the jellyfish generates asymmetries in the starting and stopping vortices. This creates a diagonal jet and a net torque acting on the jellyfish. Results are compared to immersed boundary simulations

  16. Changes in knee kinematics following total knee arthroplasty.

    PubMed

    Akbari Shandiz, Mohsen; Boulos, Paul; Saevarsson, Stefan Karl; Yoo, Sam; Miller, Stephen; Anglin, Carolyn

    2016-04-01

    Total knee arthroplasty (TKA) changes the knee joint in both intentional and unintentional, known and unknown, ways. Patellofemoral and tibiofemoral kinematics play an important role in postoperative pain, function, satisfaction and revision, yet are largely unknown. Preoperative kinematics, postoperative kinematics or changes in kinematics may help identify causes of poor clinical outcome. Patellofemoral kinematics are challenging to record since the patella is obscured by the metal femoral component in X-ray and moves under the skin. The purpose of this study was to determine the kinematic degrees of freedom having significant changes and to evaluate the variability in individual changes to allow future study of patients with poor clinical outcomes. We prospectively studied the 6 degrees of freedom patellofemoral and tibiofemoral weightbearing kinematics, tibiofemoral contact points and helical axes of rotation of nine subjects before and at least 1 year after total knee arthroplasty using clinically available computed tomography and radiographic imaging systems. Normal kinematics for healthy individuals were identified from the literature. Significant differences existed between pre-TKA and post-TKA kinematics, with the post-TKA kinematics being closer to normal. While on average the pre-total knee arthroplasty knees in this group displayed no pivoting (only translation), individually only five knees displayed this behaviour (of these, two showed lateral pivoting, one showed medial pivoting and one showed central pivoting). There was considerable variability postoperatively as well (five central, two lateral and two medial pivoting). Both preop and postop, flexion behaviour was more hinge-like medially and more rolling laterally. Helical axes were more consistent postop for this group. An inclusive understanding of the pre-TKA and post-TKA kinematics and changes in kinematics due to total knee arthroplasty could improve implant design, patient diagnosis and

  17. Architecture and Kinematics of the Taiwan Arc-Continent Collision

    NASA Astrophysics Data System (ADS)

    Carena, S.; Suppe, J.; Wu, Y. M.; Kanda, R. V. S.

    2014-12-01

    In Taiwan two subduction zones come together in quasi-orthogonal, kinematically stable configuration. Under Taiwan the upper crust of Eurasia is decoupled from the rest of the lithosphere by a detachment that forms the main subduction interface between Eurasia (EU) and Philippine Sea plate (PSP). This interface is visible in both seismicity and crustal tomography at shallow depths and can be followed into the mantle to depths of 450-500 km using global tomography. The plate interface between EU and PSP in the upper 100 km changes from about 60 degrees in the south to vertical (south-central Taiwan) to overturned (north-central Taiwan). The Eurasian Moho is similarly folded, but it does not overturn. Shortening across the plate boundary is accomplished by a combination of subduction of Eurasian lithosphere, folding and thrusting in the Eurasian upper crust, and a secondary subduction zone within the PSP. We hypothesize that: (1) once arc-continent collision occurs, subduction of Eurasian continental lower crust and upper mantle can continue by lithospheric delamination and by continuity with the much larger Eurasian slab to the south; (2) the upper crust of EU deforms by faulting and folding; (3) the present convergence rate of about 90 mm/yr is limited to the last 2 Ma, whereas the long-term rate is about 30 mm/yr and in Taiwan the difference is being taken up by secondary subduction within the PSP margin; (4) a margin-parallel STEP (Subduction-Transform-Edge-Propagator) fault forms the northern limit of Eurasian subduction, which allows the whole system to propagate self-similarly southwestward.

  18. RECENT EXPERIMENTAL STUDIES OF EDGE AND INTERNAL TRANSPORT BARRIERS IN THE DIII-D TOKAMAK

    SciTech Connect

    P. GOHIL; L.R. BAYLOR; K.H. BURRELL; T.A. CASPER; E.J. DOYLE; C.M. GREENFIELD; T.C. JERNIGAN; J.E. KINSEY; C.J LASNIER; R.A. MOYER; M. MURAKAMI; T.L. RHODES; D.L. RUDAKOV; G.M. STAEBLER; G. WANG; J.G. WATKINS; W.P. WEST; L.ZENG

    2002-08-01

    Results from recent experiments on the DIII-D tokamak have revealed many important details on transport barriers at the plasma edge and in the plasma core. These experiments include: (a) the formation of the H-mode edge barrier directly by pellet injection; (b) the formation of a quiescent H-mode edge barrier (QH-mode) which is free from edge localized modes (ELMs), but which still exhibits good density and radiative power control; (c) the formation of multiple transport barriers, such as the quiescent double barrier (QDB) which combines a internal transport barrier with the quiescent H-mode edge barrier. Results from the pellet-induced H-mode experiments indicate that: (a) the edge temperature (electron or ion) is not a critical parameter for the formation of the H-mode barrier, (b) pellet injection leads to an increased gradient in the radial electric field, E{sub r}, at the plasma edge; (c) the experimentally determined edge parameters at barrier transition are well below the predictions of several theories on the formation of the H-mode barrier, (d) pellet injection can lower the threshold power required to form the H-mode barrier. The quiescent H-mode barrier exhibits good density control as the result of continuous magnetohydrodynamic (MHD) activity at the plasma edge called the edge harmonic oscillation (EHO). The EHO enhances the edge particle transport while maintaining a good energy transport barrier. The ability to produce multiple barriers in the QDB regime has led to long duration, high performance plasmas with {beta}{sub NH{sub 89}} values of 7 for up to 10 times the confinement time. Density profile control in the plasma core of QDB plasmas has been demonstrated using on-axis ECH.

  19. Structural Analyses of the Kahiltna Terrane: A Kinematic Record of the Collision of the Talkeetna Superterrane

    NASA Astrophysics Data System (ADS)

    Bier, S. E.; Fisher, D.

    2002-12-01

    Macro-, meso-, and microscale structural analyses from several localities across the ~1000 km Kahiltna Terrane provide valuable kinematic insights into the late Cretaceous collision between the Talkeetna superterrane and North America. The Kahiltna Terrane, a Jurassic-Cretaceous flysch basin inboard of the Talkeetna superterrane (Wrangellia, Peninsular, and Alexander terranes), contains incremental strain indicators that record a history of oblique collision and subsequent deformation in a strike-slip regime. A comparison of structural data from localities across the Kahiltna terrane suggests a unique history not yet described in previous work on south-central Alaskan tectonics. Data was collected from the Reindeer Hills area, the northwestern Talkeetna Mountains, Denali National Park, the Peters Hills, and the Tordrillo Mountains. In the Reindeer Hills, a melange zone occurs as a series of exposures dismembered by ongoing strike slip faulting between the flysch of the Kahiltna terrane and the precollisional edge of the North American continent. This melange is characterized by fault-bounded blocks of Paleozoic limestone and sandstone within an argillite matrix with a conspicuous scaly fabric. The blocks range in size from 10 cm to tens of meters; and melange fish indicate a south-directed shear sense. The melange is overlain by a red and green (Triassic-Jurassic?) conglomerate along an unconformity that likely marks the base of a perched slope basin near the toe of an accretionary wedge. The strike of bedding and cleavage in this area trends EW. The fold axes trend NW-SE and folds verge to the south. In the northwest corner of the Talkeetna Mountains, the structure is dominated by north vergent folds and faults. The strike of bedding trends ~025°; whereas the strike of the cleavage is ~060°. Both cleavage and bedding dip to the southeast. The fold axes trend roughly NE-SW. North of the Denali Fault System, in Denali National Park, strike of bedding is ~122° and

  20. Modern Design of Resonant Edge-Slot Array Antennas

    NASA Technical Reports Server (NTRS)

    Gosselin, R. B.

    2006-01-01

    Resonant edge-slot (slotted-waveguide) array antennas can now be designed very accurately following a modern computational approach like that followed for some other microwave components. This modern approach makes it possible to design superior antennas at lower cost than was previously possible. Heretofore, the physical and engineering knowledge of resonant edge-slot array antennas had remained immature since they were introduced during World War II. This is because despite their mechanical simplicity, high reliability, and potential for operation with high efficiency, the electromagnetic behavior of resonant edge-slot antennas is very complex. Because engineering design formulas and curves for such antennas are not available in the open literature, designers have been forced to implement iterative processes of fabricating and testing multiple prototypes to derive design databases, each unique for a specific combination of operating frequency and set of waveguide tube dimensions. The expensive, time-consuming nature of these processes has inhibited the use of resonant edge-slot antennas. The present modern approach reduces costs by making it unnecessary to build and test multiple prototypes. As an additional benefit, this approach affords a capability to design an array of slots having different dimensions to taper the antenna illumination to reduce the amplitudes of unwanted side lobes. The heart of the modern approach is the use of the latest commercially available microwave-design software, which implements finite-element models of electromagnetic fields in and around waveguides, antenna elements, and similar components. Instead of building and testing prototypes, one builds a database and constructs design curves from the results of computational simulations for sets of design parameters. The figure shows a resonant edge-slot antenna designed following this approach. Intended for use as part of a radiometer operating at a frequency of 10.7 GHz, this antenna

  1. Development of a sensor coordinated kinematic model for neural network controller training

    NASA Technical Reports Server (NTRS)

    Jorgensen, Charles C.

    1990-01-01

    A robotic benchmark problem useful for evaluating alternative neural network controllers is presented. Specifically, it derives two camera models and the kinematic equations of a multiple degree of freedom manipulator whose end effector is under observation. The mapping developed include forward and inverse translations from binocular images to 3-D target position and the inverse kinematics of mapping point positions into manipulator commands in joint space. Implementation is detailed for a three degree of freedom manipulator with one revolute joint at the base and two prismatic joints on the arms. The example is restricted to operate within a unit cube with arm links of 0.6 and 0.4 units respectively. The development is presented in the context of more complex simulations and a logical path for extension of the benchmark to higher degree of freedom manipulators is presented.

  2. Origin and Kinematics of the Eruptive Flow from XZ Tau Revealed by ALMA

    NASA Astrophysics Data System (ADS)

    Zapata, Luis A.; Galván-Madrid, Roberto; Carrasco-González, Carlos; Curiel, Salvador; Palau, Aina; Rodríguez, Luis F.; Kurtz, Stan E.; Tafoya, Daniel; Loinard, Laurent

    2015-09-01

    We present high angular resolution (˜0.″94) 12CO(1-0) Atacama Large Millimeter/submillimeter Array (ALMA) observations obtained during the 2014 long baseline campaign from the eruptive bipolar flow from the multiple XZ Tau stellar system discovered by the Hubble Space Telescope (HST). These observations reveal, for the first time, the kinematics of the molecular flow. The kinematics of the different ejections close to XZ Tau reveal a rotating and expanding structure with a southeast-northwest velocity gradient. The youngest eruptive bubbles unveiled in the optical HST images are inside of this molecular expanding structure. Additionally, we report a very compact and collimated bipolar outflow emanating from XZ Tau A, which indicates that the eruptive outflow is indeed originating from this object. The mass (3 × 10-7 M⊙) and energetics (Ekin = 3 × 1037 erg) for the collimated outflow are comparable to those found in molecular outflows associated with young brown dwarfs.

  3. Study on general theory of kinematics and dynamics of wheeled mobile robots

    NASA Astrophysics Data System (ADS)

    Tsukishima, Takahiro; Sasaki, Ken; Takano, Masaharu; Inoue, Kenji

    1992-03-01

    This paper proposes a general theory of kinematics and dynamics of wheeled mobile robots (WMRs). Unlike robotic manipulators which are modeled as 3-dimensional serial link mechanism, WMRs will be modeled as planar linkage mechanism with multiple links branching out from the base and/or another link. Since this model resembles a tree with branches, it will be called 'tree-structured-link'. The end of each link corresponds to the wheel which is in contact with the floor. In dynamics of WMR, equation of motion of a WMR is derived from joint input torques incorporating wheel dynamics. The wheel dynamics determines forces and moments acting on wheels as a function of slip velocity. This slippage of wheels is essential in dynamics of WMR. It will also be shown that the dynamics of WMR reduces to kinematics when slippage of wheels is neglected. Furthermore, the equation of dynamics is rewritten in velocity input form, since most of industrial motors are velocity controlled.

  4. Kinematics and flow fields in 3D around swimming lamprey using light field PIV

    NASA Astrophysics Data System (ADS)

    Lehn, Andrea M.; Techet, Alexandra H.

    2016-11-01

    The fully time-resolved 3D kinematics and flow field velocities around freely swimming sea lamprey are derived using 3D light field imaging PIV. Lighthill's Elongated Body Theory (EBT) predicts that swimmers with anguilliform kinematics likened to lamprey, and similarly eels, will exhibit relatively poor propulsive efficiency. However, previous experimental studies of eel locomotion utilizing 2D PIV suggest disagreement with EBT estimates of wake properties; although, the thrust force generated by such swimmers has yet to be fully resolved using 3D measurements. A light field imaging array of multiple high-speed cameras is used to perform 3D synthetic aperture PIV around ammocoete sea lamprey (Petromyzon marinus). Fluid mechanics equations are used to determine thrust force generation, leading experimental studies closer to underpinning the physical mechanisms that enable aquatic locomotion of long, slender undulatory swimmers.

  5. Individual nectophore kinematics during multi-jet swimming by the siphonophore Nanomia bijuga

    NASA Astrophysics Data System (ADS)

    Sutherland, Kelly; Gemmell, Brad; Colin, Sean; Costello, John

    2016-11-01

    The siphonophore N. bijuga is a colonial marine organism comprised of multiple swimming units that coordinate forward and reverse swimming as well as maneuvering. Though colonies can be cms long, individual swimming units (nectophores) are mms in length. To better understand swimming kinematics and jet-wake properties at the scale of individual nectophores, we collected high speed microvideography and micro particle image velocimetry at the nectophore scale. Nectophores exhibited high pulse frequencies (3 Hz) and a rapid refill time that was roughly equal to the jet time. Forward and reverse swimming were achieved using a maneuverable velum with a triangular opening (jet nozzle) that directed flow forward or backward. Detailed velum kinematics can be applied to the design of multijet underwater vehicles with varying nozzle geometries and cross sectional areas for control of exit flow properties. Sloan Foundation.

  6. Geometric deviation modeling by kinematic matrix based on Lagrangian coordinate

    NASA Astrophysics Data System (ADS)

    Liu, Weidong; Hu, Yueming; Liu, Yu; Dai, Wanyi

    2015-09-01

    Typical representation of dimension and geometric accuracy is limited to the self-representation of dimension and geometric deviation based on geometry variation thinking, yet the interactivity affection of geometric variation and gesture variation of multi-rigid body is not included. In this paper, a kinematic matrix model based on Lagrangian coordinate is introduced, with the purpose of unified model for geometric variation and gesture variation and their interactive and integrated analysis. Kinematic model with joint, local base and movable base is built. The ideal feature of functional geometry is treated as the base body; the fitting feature of functional geometry is treated as the adjacent movable body; the local base of the kinematic model is fixed onto the ideal geometry, and the movable base of the kinematic model is fixed onto the fitting geometry. Furthermore, the geometric deviation is treated as relative location or rotation variation between the movable base and the local base, and it's expressed by the Lagrangian coordinate. Moreover, kinematic matrix based on Lagrangian coordinate for different types of geometry tolerance zones is constructed, and total freedom for each kinematic model is discussed. Finally, the Lagrangian coordinate library, kinematic matrix library for geometric deviation modeling is illustrated, and an example of block and piston fits is introduced. Dimension and geometric tolerances of the shaft and hole fitting feature are constructed by kinematic matrix and Lagrangian coordinate, and the results indicate that the proposed kinematic matrix is capable and robust in dimension and geometric tolerances modeling.

  7. Computational design of flapping kinematics of a flexible finite-span foil

    NASA Astrophysics Data System (ADS)

    Hong, Seungpyo; Lee, Jinmo; You, Donghyun

    2013-11-01

    While many of the effects of chordwise flexibility of a two-dimensional plate or a foil under pitching motions are revealed in recent computational and experimental research, the effects of flexibility of a three-dimensional foil on the manipulation of wing-tip vortices as well as leading-/trailing-edge vortices are rarely understood. The present study aims at identifying flow physics associated with flapping motions of flexible finite-span foils and the effects of the flapping kinematics and flexibility of the foil on the propulsive performance. The propulsive performance and fluid dynamics of wing-tip vortices leading-edge and trailing-edge vortices associated with the thrust generation are investigated in detail by conducting numerical simulations of flow over a flapping foil with different span-to-chord aspect ratios and bending stiffness using a recently developed coupled immersed boundary method and computational structural dynamics. Supported by the Office of Naval Research Grant N000141110652 and the National Research Foundation of Korea Grant NRF-2012R1A1A2003699.

  8. The shape of dark matter haloes - III. Kinematics and structure of the H I disc

    NASA Astrophysics Data System (ADS)

    Peters, S. P. C.; van der Kruit, P. C.; Allen, R. J.; Freeman, K. C.

    2017-01-01

    We present a new strategy for fitting the structure and kinematics of the H I in edge-on galaxies using a fit to the terminal-velocity channel maps of a H I data cube. The strategy can deal with self-absorbing H I gas and the presence of warps. The method is first tested on a series of models. We demonstrate that fitting optically thin models to real galaxies will lead to an overestimation of the thickness and velocity dispersion, and to a serious underestimation of the H I face-on column densities. We subsequently fit both self-absorption and optically thin models to the H I data of six edge-on galaxies. In three of these, we have also measured the velocity dispersion. On average, 27 ± 6 per cent of the total H I mass of edge-on galaxies is hidden by self-absorption. This implies that the H I mass, thickness and velocity dispersion of galaxies is typically underestimated in the literature.

  9. Results from the EDGES Survey

    NASA Astrophysics Data System (ADS)

    van Zee, Liese; EDGES Team

    2017-03-01

    Results are presented from a deep imaging survey with the Spitzer Space Telescope which was designed to identify and measure the faint stellar populations around nearby galaxies. The Extended Disk Galaxy Exploration Science (EDGES) Survey includes a sample of 92 nearby galaxies with a range of morphological types and environments. The observations include a field-of-view of at least 5 times the optical size and are deep enough to detect stellar mass surface densities of several hundredths of a solar mass per square parsec. The observations reveal extended stellar features, such as stellar disks and stellar streams, around many of the target galaxies, as expected from hierarchical galaxy formation scenarios.

  10. K-edge densitometer (KED)

    SciTech Connect

    Sprinkle, J.K.; Hansen, W.J.

    1993-02-11

    In 1979, a K-edge densitometer (KED) was installed by the Safeguards Assay group from Los Alamos National Laboratory in the PNC reprocessing plant at Tokai-mura, Japan. It uses an active nondestructive assay technique, KED, to measure the plutonium concentration of the product solution. The measurement uncertainty of an assay depends on the count time chosen, but can be 0.5% or better. The computer hardware and software were upgraded in 1992. This manual describes the operation of the instrument, with an emphasis on the user interface to the software.

  11. Environmental Dataset Gateway (EDG) Search Widget

    EPA Pesticide Factsheets

    Use the Environmental Dataset Gateway (EDG) to find and access EPA's environmental resources. Many options are available for easily reusing EDG content in other other applications. This allows individuals to provide direct access to EPA's metadata outside the EDG interface. The EDG Search Widget makes it possible to search the EDG from another web page or application. The search widget can be included on your website by simply inserting one or two lines of code. Users can type a search term or lucene search query in the search field and retrieve a pop-up list of records that match that search.

  12. Environmental Dataset Gateway (EDG) REST Interface

    EPA Pesticide Factsheets

    Use the Environmental Dataset Gateway (EDG) to find and access EPA's environmental resources. Many options are available for easily reusing EDG content in other other applications. This allows individuals to provide direct access to EPA's metadata outside the EDG interface. The EDG REST Interface allows each users to query the catalog through a URL using REST syntax. Accessing individual metadata documents through their REST URLs, or groups of documents that match specific search criteria through a REST-formatted search URL, provides powerful functionality for searching, viewing, and sharing EDG records.

  13. Fractal-based image edge detection

    NASA Astrophysics Data System (ADS)

    Luo, Huiguo; Zhu, Yaoting; Zhu, Guang-Xi; Wan, Faguang; Zhang, Ping

    1993-08-01

    Image edge is an important feature of image. Usually, we use Laplacian or Sober operator to get an image edge. In this paper, we use fractal method to get the edge. After introducing Fractal Brownian Random (FBR) field, we give the definition of Discrete Fractal Brownian Increase Random (DFBIR) field and discuss its properties, then we apply the DFBIR field to detect the edge of an image. According to the parameters H and D of DFBIR, we give a measure M equals (alpha) H + (beta) D. From the M value of each pixel, we can detect the edge of image.

  14. The SLUGGS Survey: A New Mask Design to Reconstruct the Stellar Populations and Kinematics of Both Inner and Outer Galaxy Regions

    NASA Astrophysics Data System (ADS)

    Pastorello, Nicola; Forbes, Duncan A.; Poci, Adriano; Romanowsky, Aaron J.; McDermid, Richard; Alabi, Adebusola B.; Brodie, Jean P.; Cappellari, Michele; Pota, Vincenzo; Foster, Caroline

    2016-08-01

    Integral field unit spectrographs allow the 2D exploration of the kinematics and stellar populations of galaxies, although they are generally restricted to small fields-of-view. Using the large field-of-view of the DEIMOS multislit spectrograph on Keck and our Stellar Kinematics using Multiple Slits technique, we are able to extract sky-subtracted stellar light spectra to large galactocentric radii. Here, we present a new DEIMOS mask design named SuperSKiMS that explores large spatial scales without sacrificing high spatial sampling. We simulate a set of observations with such a mask design on the nearby galaxy NGC 1023, measuring stellar kinematics and metallicities out to where the galaxy surface brightness is orders of magnitude fainter than the sky. With this technique we also reproduce the results from literature integral field spectroscopy in the innermost galaxy regions. In particular, we use the simulated NGC 1023 kinematics to model its total mass distribution to large radii, obtaining comparable results with those from published integral field unit observation. Finally, from new spectra of NGC 1023, we obtain stellar 2D kinematics and metallicity distributions that show good agreement with integral field spectroscopy results in the overlapping regions. In particular, we do not find a significant offset between our Stellar Kinematics using Multiple Slits and the ATLAS3D stellar velocity dispersion at the same spatial locations.

  15. Multiplanar breast kinematics during different exercise modalities.

    PubMed

    Risius, Deborah; Milligan, Alexandra; Mills, Chris; Scurr, Joanna

    2015-01-01

    Multiplanar breast movement reduction is crucial to increasing physical activity participation amongst women. To date, research has focused on breast movement during running, but until breast movement is understood during different exercise modalities, the breast support requirements for specific activities are unknown. To understand breast support requirements during different exercise modalities, this study aimed to determine multiplanar breast kinematics during running, jumping and agility tasks. Sixteen 32D participants had markers attached to their right nipple and torso. Relative multiplanar breast displacement was calculated during bare-breasted treadmill running (10 kph), maximum countermovement jumping and an agility t-test. Exercise modality influenced the magnitude and direction of breast displacement, velocity and acceleration (p < .05). Jumping produced greater vertical breast displacement (.09 m) but less mediolateral breast displacement (.05 m) than running or the agility task, but agility tasks produced the highest multiplanar breast velocities and acceleration. Breast movement during jumping was predominantly in the vertical direction, whereas the agility task produced a greater percentage of mediolateral breast acceleration than running or jumping. Exercise modality impacted upon the magnitude and distribution of bare-breasted multiplanar breast kinematics in this homogenous 32D cohort. Therefore, to reduce breast movement in women of a 32D bra size, manufacturers may wish to design sport-specific products, with greater vertical support for exercise modalities incorporating jumping and greater mediolateral support for agility tasks.

  16. The Kinematics of Turbulent Boundary Layer Structure

    NASA Technical Reports Server (NTRS)

    Robinson, Stephen Kern

    1991-01-01

    The long history of research into the internal structure of turbulent boundary layers has not provided a unified picture of the physics responsible for turbulence production and dissipation. The goals of the present research are to: (1) define the current state of boundary layer structure knowledge; and (2) utilize direct numerical simulation results to help close the unresolved issues identified in part A and to unify the fragmented knowledge of various coherent motions into a consistent kinematic model of boundary layer structure. The results of the current study show that all classes of coherent motion in the low Reynolds number turbulent boundary layer may be related to vortical structures, but that no single form of vortex is representative of the wide variety of vortical structures observed. In particular, ejection and sweep motions, as well as entrainment from the free-streem are shown to have strong spatial and temporal relationships with vortical structures. Disturbances of vortex size, location, and intensity show that quasi-streamwise vortices dominate the buffer region, while transverse vortices and vortical arches dominate the wake region. Both types of vortical structure are common in the log region. The interrelationships between the various structures and the population distributions of vortices are combined into a conceptual kinematic model for the boundary layer. Aspects of vortical structure dynamics are also postulated, based on time-sequence animations of the numerically simulated flow.

  17. Kinematics of Signature Writing in Healthy Aging*

    PubMed Central

    Caligiuri, Michael P.; Kim, Chi; Landy, Kelly M.

    2014-01-01

    Forensic document examiners (FDE) called upon to distinguish a genuine from a forged signature of an elderly person are often required to consider the question of age-related deterioration and whether the available exemplars reliably capture the natural effects of aging of the original writer. An understanding of the statistical relationship between advanced age and handwriting movements can reduce the uncertainty that may exist in an examiner’s approach to questioned signatures formed by elderly writers. The primary purpose of this study was to systematically examine age-related changes in signature kinematics in healthy writers. Forty-two healthy subjects between the ages of 60–91 years participated in this study. Signatures were recorded using a digitizing tablet and commercial software was used to examine the temporal and spatial stroke kinematics and pen pressure. Results indicated that vertical stroke duration and dysfluency increased with age, whereas vertical stroke amplitude and velocity decreased with age. Pen pressure decreased with age. We found that a linear model characterized the best-fit relationship between advanced age and handwriting movement parameters for signature formation. Male writers exhibited stronger age effects than female writers, especially for pen pressure and stroke dysfluency. The present study contributes to an understanding of how advanced age alters signature formation in otherwise healthy adults. PMID:24673648

  18. Nuclear Rings in Galaxies - A Kinematic Perspective

    NASA Technical Reports Server (NTRS)

    Mazzuca, Lisa M.; Swaters, Robert A.; Knapen, Johan H.; Veilleux, Sylvain

    2011-01-01

    We combine DensePak integral field unit and TAURUS Fabry-Perot observations of 13 nuclear rings to show an interconnection between the kinematic properties of the rings and their resonant origin. The nuclear rings have regular and symmetric kinematics, and lack strong non-circular motions. This symmetry, coupled with a direct relationship between the position angles and ellipticities of the rings and those of their host galaxies, indicate the rings are in the same plane as the disc and are circular. From the rotation curves derived, we have estimated the compactness (v(sup 2)/r) up to the turnover radius, which is where the nuclear rings reside. We find that there is evidence of a correlation between compactness and ring width and size. Radially wide rings are less compact, and thus have lower mass concentration. The compactness increases as the ring width decreases. We also find that the nuclear ring size is dependent on the bar strength, with weaker bars allowing rings of any size to form.

  19. Kinematically consistent models of viscoelastic stress evolution

    NASA Astrophysics Data System (ADS)

    DeVries, Phoebe M. R.; Meade, Brendan J.

    2016-05-01

    Following large earthquakes, coseismic stresses at the base of the seismogenic zone may induce rapid viscoelastic deformation in the lower crust and upper mantle. As stresses diffuse away from the primary slip surface in these lower layers, the magnitudes of stress at distant locations (>1 fault length away) may slowly increase. This stress relaxation process has been used to explain delayed earthquake triggering sequences like the 1992 Mw = 7.3 Landers and 1999 Mw = 7.1 Hector Mine earthquakes in California. However, a conceptual difficulty associated with these models is that the magnitudes of stresses asymptote to constant values over long time scales. This effect introduces persistent perturbations to the total stress field over many earthquake cycles. Here we present a kinematically consistent viscoelastic stress transfer model where the total perturbation to the stress field at the end of the earthquake cycle is zero everywhere. With kinematically consistent models, hypotheses about the potential likelihood of viscoelastically triggered earthquakes may be based on the timing of stress maxima, rather than on any arbitrary or empirically constrained stress thresholds. Based on these models, we infer that earthquakes triggered by viscoelastic earthquake cycle effects may be most likely to occur during the first 50% of the earthquake cycle regardless of the assumed long-term and transient viscosities.

  20. A Simplified Scheme for Kinematic Source Inversion

    NASA Astrophysics Data System (ADS)

    Iglesias, A.; Castro-Artola, O.; Singh, S.; Hjorleifsdottir, V.; Legrand, D.

    2013-05-01

    It is well known that different kinematic source inversion schemes lead to non-unique solutions. For this reason, a simplified scheme, which yields the main characteristics of the rupture process, rather than the details, may be desirable. In this work we propose a modification of the frequency-domain inversion scheme of Cotton & Campillo (1995) to extract kinematic parameters using simplified geometries (ellipses). The forward problem is re-parameterized by including one or two ellipses in which the displacement is smoothly distributed. For the ellipses we invert for the position of the centers within the fault plane, the major and minor semi-axes, the maximum displacements, the angles of rotation and a parameter that controls the distribution of slip. A simulated annealing scheme is used to invert near-source displacements. We first test the method on synthetic displacement records corresponding to the Guerrero-Oaxaca earthquake (20/03/2012, Mw=7.5) by comparing the results obtained from the modified technique with the original method. In the next step, we use displacements obtained by double numerical integration of recorded accelerograms. We find that, in spite of the simple geometry, the modified method leads to a good fit between observed and synthetic displacements and recovers the main rupture characteristics.

  1. Friction Stir Welding at MSFC: Kinematics

    NASA Technical Reports Server (NTRS)

    Nunes, A. C., Jr.

    2001-01-01

    In 1991 The Welding Institute of the United Kingdom patented the Friction Stir Welding (FSW) process. In FSW a rotating pin-tool is inserted into a weld seam and literally stirs the faying surfaces together as it moves up the seam. By April 2000 the American Welding Society International Welding and Fabricating Exposition featured several exhibits of commercial FSW processes and the 81st Annual Convention devoted a technical session to the process. The FSW process is of interest to Marshall Space Flight Center (MSFC) as a means of avoiding hot-cracking problems presented by the 2195 aluminum-lithium alloy, which is the primary constituent of the Lightweight Space Shuttle External Tank. The process has been under development at MSFC for External Tank applications since the early 1990's. Early development of the FSW process proceeded by cut-and-try empirical methods. A substantial and complex body of data resulted. A theoretical model was wanted to deal with the complexity and reduce the data to concepts serviceable for process diagnostics, optimization, parameter selection, etc. A first step in understanding the FSW process is to determine the kinematics, i.e., the flow field in the metal in the vicinity of the pin-tool. Given the kinematics, the dynamics, i.e., the forces, can be targeted. Given a completed model of the FSW process, attempts at rational design of tools and selection of process parameters can be made.

  2. The SPM Kinematic Catalogue of Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    López, J. A.; Richer, M.; Riesgo, H.; Steffen, W.; Meaburn, J.; García-Segura, G.; Escalante, K.

    2006-06-01

    We present a progress report on the San Pedro Mártir Kinematic Catalogue of Planetary Nebulae. Both, galactic PNe from the disk, bulge and halo populations, and PNe from galaxies in the local group from a diverse range of metallicities have been observed. Most of the observations have been made with the 2.1-m SPM telescope and the Manchester Echelle Spectrometer (Meaburn et al. 2003, RevMexAA, 39, 185). The data consists of spatially resoved long slit spectra at resolutions of ˜ 10 km s^{-1}. For most galactic targets more than one slit positions has been observed. The interpretation of the 3D structures and outflows derived from the kinematic data is being performed with the aid of SHAPE (see the contributions by Steffen, López, & Escalante, Steffen & López in this symposium). This unique database of high dispersion spectra will allow a firm characterisation of nebular shell properties in relation to progenitors from diverse stellar populations.

  3. Against relative timing invariance in movement kinematics.

    PubMed

    Burgess-Limerick, R; Neal, R J; Abernethy, B

    1992-05-01

    The kinematics of stair climbing were examined to test the assertion that relative timing is an invariant feature of human gait. Six male and four female subjects were video-recorded (at 60 Hz) while they climbed a flight of stairs 10 times at each of three speeds. Each gait cycle was divided into three segments by the maximum and minimum angular displacement of the left knee and left foot contact. Gentner's (1987) analysis methods were applied to the individual subject data to determine whether the duration of the segments remained a fixed proportion of gait cycle duration across changes in stair-climbing speed. A similar analysis was performed using knee velocity maxima to partition the gait cycle. Regardless of how the gait cycle was divided, relative timing was not found to remain strictly invariant across changes in speed. This conclusion is contrary to previous studies of relative timing that involved less conservative analysis but is consistent with the wider gait literature. Strict invariant relative timing may not be a fundamental feature of movement kinematics.

  4. Kinematic criterion for breaking of shoaling waves

    NASA Astrophysics Data System (ADS)

    Liberzon, Dan; Itay, Uri

    2016-11-01

    Validity of a kinematic criterion for breaking of shoaling waves was examined experimentally. Results obtained by simultaneous measurements of water surface velocity by PTV and of the propagation velocity of a steep crest up to the point of breaking inception during shoaling will be reported. The experiments performed in a large wave tank examining breaking behavior of gentle spillers during shoaling on three different slopes suggest a validity of the recently proposed kinematic criterion. The breaking inception was found to occur when the horizontal velocity of the water surface on the steep (local steepness of 0.41-0.6) crest reaches a threshold value of 0.85-0.95 of that of the crest propagation. The exact moment and position of breaking inception detected using a Phase Time Method (PTM), characterizing a unique shape of the local frequency fluctuations at the inception. Future implementation of the PTM method for detection of breaking events in irregular wave fields will be discussed. Supported by German-Israeli Foundation for Scientific Research and Development (GIF) Grant #2019392.

  5. THE KINEMATICS OF PRIMATE MIDFOOT FLEXIBILITY

    PubMed Central

    Greiner, Thomas M.; Ball, Kevin A.

    2015-01-01

    This study describes a unique assessment of primate intrinsic foot joint kinematics based upon bone pin rigid cluster tracking. It challenges the assumption that human evolution resulted in a reduction of midfoot flexibility, which has been identified in other primates as the “midtarsal break.” Rigid cluster pins were inserted into the foot bones of human, chimpanzee, baboon and macaque cadavers. The positions of these bone pins were monitored during a plantarflexion-dorsiflexion movement cycle. Analysis resolved flexion-extension movement patterns and the associated orientation of rotational axes for the talonavicular, calcaneocuboid and lateral cubometatarsal joints. Results show that midfoot flexibility occurs primarily at the talonavicular and cubometatarsal joints. The rotational magnitudes are roughly similar between humans and chimps. There is also a similarity among evaluated primates in the observed rotations of the lateral cubometatarsal joint, but there was much greater rotation observed for the talonavicular joint, which may serve to differentiate monkeys from the hominines. It appears that the capability for a midtarsal break is present within the human foot. A consideration of the joint axes shows that the medial and lateral joints have opposing orientations, which has been associated with a rigid locking mechanism in the human foot. However, the potential for this same mechanism also appears in the chimpanzee foot. These findings demonstrate a functional similarity within the midfoot of the hominines. Therefore, the kinematic capabilities and restrictions for the skeletal linkages of the human foot may not be as unique as has been previously suggested. PMID:25234343

  6. Evaluating Edge Detection through Boundary Detection

    NASA Astrophysics Data System (ADS)

    Wang, Song; Ge, Feng; Liu, Tiecheng

    2006-12-01

    Edge detection has been widely used in computer vision and image processing. However, the performance evaluation of the edge-detection results is still a challenging problem. A major dilemma in edge-detection evaluation is the difficulty to balance the objectivity and generality: a general-purpose edge-detection evaluation independent of specific applications is usually not well defined, while an evaluation on a specific application has weak generality. Aiming at addressing this dilemma, this paper presents new evaluation methodology and a framework in which edge detection is evaluated through boundary detection, that is, the likelihood of retrieving the full object boundaries from this edge-detection output. Such a likelihood, we believe, reflects the performance of edge detection in many applications since boundary detection is the direct and natural goal of edge detection. In this framework, we use the newly developed ratio-contour algorithm to group the detected edges into closed boundaries. We also collect a large data set ([InlineEquation not available: see fulltext.]) of real images with unambiguous ground-truth boundaries for evaluation. Five edge detectors (Sobel, LoG, Canny, Rothwell, and Edison) are evaluated in this paper and we find that the current edge-detection performance still has scope for improvement by choosing appropriate detectors and detector parameters.

  7. A novel algorithm for the edge detection and edge enhancement of medical images.

    PubMed

    Crooks, I; Fallone, B G

    1993-01-01

    A novel algorithm, histogram shifting (HS) is presented, which performs edge detection or edge enhancement with the choice of two parameters. The histogram of a region surrounding each pixel is found and translated toward the origin, resulting in the new pixel value. Images from a variety of medical imaging modalities were processed with HS to perform detection and enhancement of edges. Comparison with results obtained from conventional edge detection (e.g., Sobel) and with conventional edge-enhancement algorithms is discussed. HS appears to perform the edge-detection operation without introducing "double-edge" effects often obtained with conventional edge-detection algorithms. HS also appears to perform edge enhancement without introducing extensive noise artifacts, which may be noticeable with many edge-enhancement algorithms.

  8. Dynamical modelling of coordinated multiple robot systems

    NASA Technical Reports Server (NTRS)

    Hayati, Samad

    1987-01-01

    The state of the art in the modeling of the dynamics of coordinated multiple robot manipulators is summarized and various problems related to this subject are discussed. It is recognized that dynamics modeling is a component used in the design of controllers for multiple cooperating robots. As such, the discussion addresses some problems related to the control of multiple robots. The techniques used to date in the modeling of closed kinematic chains are summarized. Various efforts made to date for the control of coordinated multiple manipulators is summarized.

  9. Measuring edge importance to improve immunization performance

    NASA Astrophysics Data System (ADS)

    Huang, He; Yan, Zhijun; Pan, Yaohui

    2014-12-01

    The edge heterogeneity has a remarkable influence on disease spreading, but it has seldom been considered in the disease-controlling policies. Based on the gravity model, we propose the edge importance index to describe the influence of edge heterogeneity on immunization strategies. Then the edge importance and contact weight are combined to calculate the infection rates on the I-S (Infected-Susceptible) edges in the complex network, and the difference of the infection rates on strong and weak ties is analyzed. Simulation results show that edge heterogeneity has a significant influence on the performance of immunization strategies, and better immunization efficiency is derived when the vaccination rate of the nodes in the weak I-S edges is increased.

  10. Teaching and Evaluation Materials Utilizing Multiple Representations in Mechanics

    ERIC Educational Resources Information Center

    Savinainen, A.; Nieminen, P.; Makynen, A.; Viiri, J.

    2013-01-01

    In this paper, we present materials and teaching ideas utilizing multiple representations in the contexts of kinematics and the force concept. These ideas and materials are substantiated by evidence and can be readily used in teaching with no special training. In addition, we briefly discuss two multiple-choice tests based on physics education…

  11. Reflections on the Knife Edge

    PubMed Central

    Murphy, John Patrick Michael

    2011-01-01

    Introduction The accompanying article, written by John Murphy, a retired lawyer and lifelong outdoorsman from his beloved Colorado Rockies, draws the striking parallel between his experiences as a mountain climber and as a patient with metastatic melanoma facing the hope and uncertainty of experimental therapy. Both are life-threatening circumstances, demanding courage and hope, and challenging our soul in a way almost unique to human experience. Both involve a conscious choice to move forward into dangerous and uncertain territory, and require a determination to look death (John's “Reaper”) in the eye. Many remarkable books and films have been written about such experiences. I recall in particular the 2003 documentary film Touching the Void, about the incredible survival of a mountaineer who returned from a perilous fall in Peru. I highly recommend it to the reader. Another is Laura Hillenbrand's Unbroken: A World War II Story of Survival, Resilience, and Redemption (Random House, 2010), about the survival of a prisoner of war, the celebrated miler Louis Zamperini. Again, unbridled courage and undeniable hope turned futility into future. John Murphy's reflections remind us of the daily heroism of our patients who are holding tight to the lifeline offered by clinical research. Good climbing, John. All of us are with you on that Knife Edge, waiting for our turn to ascend... and hoping to be as courageous as you were then on Capitol Peak and are again now on the Knife Edge of a clinical trial. For our turn will come. PMID:21349953

  12. Haptic Edge Detection Through Shear

    NASA Astrophysics Data System (ADS)

    Platkiewicz, Jonathan; Lipson, Hod; Hayward, Vincent

    2016-03-01

    Most tactile sensors are based on the assumption that touch depends on measuring pressure. However, the pressure distribution at the surface of a tactile sensor cannot be acquired directly and must be inferred from the deformation field induced by the touched object in the sensor medium. Currently, there is no consensus as to which components of strain are most informative for tactile sensing. Here, we propose that shape-related tactile information is more suitably recovered from shear strain than normal strain. Based on a contact mechanics analysis, we demonstrate that the elastic behavior of a haptic probe provides a robust edge detection mechanism when shear strain is sensed. We used a jamming-based robot gripper as a tactile sensor to empirically validate that shear strain processing gives accurate edge information that is invariant to changes in pressure, as predicted by the contact mechanics study. This result has implications for the design of effective tactile sensors as well as for the understanding of the early somatosensory processing in mammals.

  13. Haptic Edge Detection Through Shear

    PubMed Central

    Platkiewicz, Jonathan; Lipson, Hod; Hayward, Vincent

    2016-01-01

    Most tactile sensors are based on the assumption that touch depends on measuring pressure. However, the pressure distribution at the surface of a tactile sensor cannot be acquired directly and must be inferred from the deformation field induced by the touched object in the sensor medium. Currently, there is no consensus as to which components of strain are most informative for tactile sensing. Here, we propose that shape-related tactile information is more suitably recovered from shear strain than normal strain. Based on a contact mechanics analysis, we demonstrate that the elastic behavior of a haptic probe provides a robust edge detection mechanism when shear strain is sensed. We used a jamming-based robot gripper as a tactile sensor to empirically validate that shear strain processing gives accurate edge information that is invariant to changes in pressure, as predicted by the contact mechanics study. This result has implications for the design of effective tactile sensors as well as for the understanding of the early somatosensory processing in mammals. PMID:27009331

  14. Development of an edge sensor based on polyview optics and laser triangulation principle

    NASA Astrophysics Data System (ADS)

    Li, Yinan; Bossmeyer, Hagen; Kästner, Markus; Reithmeier, Eduard

    2016-11-01

    Common 2D laser line triangulation sensors allow a 2D profile measurement in a single line. To scan samples with great curved surfaces like edges, a single laser line triangulation sensor is insufficient. To measure the entire form of such an edge, it normally requires either multiple measurements of one single sensor or a multi sensor system. For this reason, we developed an edge measurement sensor based on an in-house designed polyview optics and the well-known laser triangulation principle. The new developed edge measurement sensor is capable of measuring the object over a 180 field of view (FOV). The configuration, the calibration process and the measurement results of this edge sensor will be discussed in this paper.

  15. Dynamics of skyrmions and edge states in the resistive regime of mesoscopic p-wave superconductors

    NASA Astrophysics Data System (ADS)

    Fernández Becerra, V.; Milošević, M. V.

    2017-02-01

    In a mesoscopic sample of a chiral p-wave superconductor, novel states comprising skyrmions and edge states have been stabilized in out-of-plane applied magnetic field. Using the time-dependent Ginzburg-Landau equations we shed light on the dynamic response of such states to an external applied current. Three different regimes are obtained, namely, the superconducting (stationary), resistive (non-stationary) and normal regime, similarly to conventional s-wave superconductors. However, in the resistive regime and depending on the external current, we found that moving skyrmions and the edge state behave distinctly different from the conventional kinematic vortex, thereby providing new fingerprints for identification of p-wave superconductivity.

  16. Investigating Disk-halo Flows and Accretion: A Kinematic and Morphological Analysis of Extraplanar H I in NGC 3044 and NGC 4302

    NASA Astrophysics Data System (ADS)

    Zschaechner, Laura K.; Rand, Richard J.; Walterbos, Rene

    2015-01-01

    To further understand the origins of and physical processes operating in extra-planar gas, we present observations and kinematic models of H I in the two nearby, edge-on spiral galaxies NGC 3044 and NGC 4302. We model NGC 3044 as a single, thick disk. Substantial amounts of extra-planar H I are also detected. We detect a decrease in rotation speed with height (a lag) that shallows radially, reaching zero at approximately R 25. The large-scale kinematic asymmetry of the approaching and receding halves suggests a recent disturbance. The kinematics and morphology of NGC 4302, a Virgo Cluster member, are greatly disturbed. We model NGC 4302 as a combination of a thin disk and a second, thicker disk, the latter having a hole near the center. We detect lagging extra-planar gas, with indications of shallowing in the receding half, although its characteristics are difficult to constrain. A bridge is detected between NGC 4302 and its companion, NGC 4298. We explore trends involving the extra-planar H I kinematics of these galaxies, as well as galaxies throughout the literature, as well as possible connections between lag properties with star formation and environment. Measured lags are found to be significantly steeper than those modeled by purely ballistic effects, indicating additional factors. Radial shallowing of extra-planar lags is typical and occurs between 0.5R 25 and R 25, suggesting internal processes are important in dictating extra-planar kinematics.

  17. Edge detection in microscopy images using curvelets

    PubMed Central

    Gebäck, Tobias; Koumoutsakos, Petros

    2009-01-01

    Background Despite significant progress in imaging technologies, the efficient detection of edges and elongated features in images of intracellular and multicellular structures acquired using light or electron microscopy is a challenging and time consuming task in many laboratories. Results We present a novel method, based on the discrete curvelet transform, to extract a directional field from the image that indicates the location and direction of the edges. This directional field is then processed using the non-maximal suppression and thresholding steps of the Canny algorithm to trace along the edges and mark them. Optionally, the edges may then be extended along the directions given by the curvelets to provide a more connected edge map. We compare our scheme to the Canny edge detector and an edge detector based on Gabor filters, and show that our scheme performs better in detecting larger, elongated structures possibly composed of several step or ridge edges. Conclusion The proposed curvelet based edge detection is a novel and competitive approach for imaging problems. We expect that the methodology and the accompanying software will facilitate and improve edge detection in images available using light or electron microscopy. PMID:19257905

  18. A School Experiment in Kinematics: Shooting from a Ballistic Cart

    ERIC Educational Resources Information Center

    Kranjc, T.; Razpet, N.

    2011-01-01

    Many physics textbooks start with kinematics. In the lab, students observe the motions, describe and make predictions, and get acquainted with basic kinematics quantities and their meaning. Then they can perform calculations and compare the results with experimental findings. In this paper we describe an experiment that is not often done, but is…

  19. Lingual Kinematics during Rapid Syllable Repetition in Parkinson's Disease

    ERIC Educational Resources Information Center

    Wong, Min Ney; Murdoch, Bruce E.; Whelan, Brooke-Mai

    2012-01-01

    Background: Rapid syllable repetition tasks are commonly used in the assessment of motor speech disorders. However, little is known about the articulatory kinematics during rapid syllable repetition in individuals with Parkinson's disease (PD). Aims: To investigate and compare lingual kinematics during rapid syllable repetition in dysarthric…

  20. Zero-Inertial Recession for a Kinematic Wave Model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Kinematic-wave models of surface irrigation assume a fixed relationship between depth and discharge (typically, normal depth). When surface irrigation inflow is cut off, the calculated upstream flow depth goes to zero, since the discharge is zero. For short time steps, use of the Kinematic Wave mode...

  1. Kinematics Card Sort Activity: Insight into Students' Thinking

    ERIC Educational Resources Information Center

    Berryhill, Erin; Herrington, Deborah; Oliver, Keith

    2016-01-01

    Kinematics is a topic students are unknowingly aware of well before entering the physics classroom. Students observe motion on a daily basis. They are constantly interpreting and making sense of their observations, unintentionally building their own understanding of kinematics before receiving any formal instruction. Unfortunately, when students…

  2. Kinematic Signatures of Telic and Atelic Events in ASL Predicates

    ERIC Educational Resources Information Center

    Malaia, Evie; Wilbur, Ronnie B.

    2012-01-01

    This article presents an experimental investigation of kinematics of verb sign production in American Sign Language (ASL) using motion capture data. The results confirm that event structure differences in the meaning of the verbs are reflected in the kinematic formation: for example, in the telic verbs (throw, hit), the end-point of the event is…

  3. Aerodynamic forces and flow structures of the leading edge vortex on a flapping wing considering ground effect.

    PubMed

    Van Truong, Tien; Byun, Doyoung; Kim, Min Jun; Yoon, Kwang Joon; Park, Hoon Cheol

    2013-09-01

    The aim of this work is to provide an insight into the aerodynamic performance of the beetle during takeoff, which has been estimated in previous investigations. We employed a scaled-up electromechanical model flapping wing to measure the aerodynamic forces and the three-dimensional flow structures on the flapping wing. The ground effect on the unsteady forces and flow structures were also characterized. The dynamically scaled wing model could replicate the general stroke pattern of the beetle's hind wing kinematics during takeoff flight. Two wing kinematic models have been studied to examine the influences of wing kinematics on unsteady aerodynamic forces. In the first model, the angle of attack is asymmetric and varies during the translational motion, which is the flapping motion of the beetle's hind wing. In the second model, the angle of attack is constant during the translational motion. The instantaneous aerodynamic forces were measured for four strokes during the beetle's takeoff by the force sensor attached at the wing base. Flow visualization provided a general picture of the evolution of the three-dimensional leading edge vortex (LEV) on the beetle hind wing model. The LEV is stable during each stroke, and increases radically from the root to the tip, forming a leading-edge spiral vortex. The force measurement results show that the vertical force generated by the hind wing is large enough to lift the beetle. For the beetle hind wing kinematics, the total vertical force production increases 18.4% and 8.6% for the first and second strokes, respectively, due to the ground effect. However, for the model with a constant angle of attack during translation, the vertical force is reduced during the first stroke. During the third and fourth strokes, the ground effect is negligible for both wing kinematic patterns. This finding suggests that the beetle's flapping mechanism induces a ground effect that can efficiently lift its body from the ground during takeoff.

  4. Kinematic modeling and path planning for MIRADAS arms

    NASA Astrophysics Data System (ADS)

    Sabater, Josep; Gómez, José María.; López, Manuel; Torra, Jordi; Raines, Steven N.; Eikenberry, Stephen S.

    2014-07-01

    The Mid-resolution InfRAreD Astronomical Spectrograph (MIRADAS) is a near-infrared (NIR) multi-object spectrograph for the Gran Telescopio Canarias (GTC). It can simultaneously observe multiple targets selected by 20 identical deployable probe arms with pickoff mirror optics. The bases of the arms are fixed to the multiplexing system (MXS) plate, a circular platform, and arranged in a circular layout with minimum separation between elements of the arms. This document presents the MXS prototype P2a, a full-scale, fully operational prototype of a MIRADAS probe arm. This planar closed-loop mechanism compared to other previous designs offers some advantages specially in terms of stability and from the point of view of optics. Unfortunately, these benefits come at the expense of a more complicated kinematics and an unintuitive arm motion. Furthermore, the cryogenic motor controllers used in prototyping impose severe restrictions in path planing. They negatively impact in the slice of pie approach, a collision-avoidance patrolling strategy that can gives good results in other scenarios. This study is a starting point to define collision-free trajectory algorithms for the 20 probe arms of MIRADAS.

  5. Forward and inverse kinematics of double universal joint robot wrists

    NASA Technical Reports Server (NTRS)

    Williams, Robert L., II

    1991-01-01

    A robot wrist consisting of two universal joints can eliminate the wrist singularity problem found on many individual robots. Forward and inverse position and velocity kinematics are presented for such a wrist having three degrees of freedom. Denavit-Hartenberg parameters are derived to find the transforms required for the kinematic equations. The Omni-Wrist, a commercial double universal joint robot wrist, is studied in detail. There are four levels of kinematic parameters identified for this wrist; three forward and three inverse maps are presented for both position and velocity. These equations relate the hand coordinate frame to the wrist base frame. They are sufficient for control of the wrist standing alone. When the wrist is attached to a manipulator arm; the offset between the two universal joints complicates the solution of the overall kinematics problem. All wrist coordinate frame origins are not coincident, which prevents decoupling of position and orientation for manipulator inverse kinematics.

  6. Numerical analysis of kinematic soil—pile interaction

    NASA Astrophysics Data System (ADS)

    Castelli, Francesco; Maugeri, Michele; Mylonakis, George

    2008-07-01

    In the present study, the response of singles pile to kinematic seismic loading is investigated using the computer program SAP2000@. The objectives of the study are: (1) to develop a numerical model that can realistically simulate kinematic soil-structure interaction for piles accounting for discontinuity conditions at the pile-soil interface, energy dissipation and wave propagation; (2) to use the model for evaluating kinematic interaction effects on pile response as function of input ground motion; and (3) to present a case study in which theoretical predictions are compared with results obtained from other formulations. To evaluate the effects of kinematic loading, the responses of both the free-field soil (with no piles) and the pile were compared. Time history and static pushover analyses were conducted to estimate the displacement and kinematic pile bending under seismic loadings.

  7. Polarity control of h-BN nanoribbon edges by strain and edge termination.

    PubMed

    Yamanaka, Ayaka; Okada, Susumu

    2017-03-29

    We studied the polarity of h-BN nano-flakes in terms of their edge geometries, edge hydrogen termination, and uniaxial strain by evaluating their electrostatic potential using density functional theory. Our calculations have shown that the polarity of the nanoribbons is sensitive to their edge shape, edge termination, and uniaxial tensile strain. Polarity inversion of the ribbons can be induced by controlling the hydrogen concentration at the edges and the uniaxial tensile strain. The polarity inversion indicates that h-BN nanoribbons can exhibit non-polar properties at a particular edge hydrogen concentration and tensile strain, even though the nanoribbons essentially have polarity at the edge. We also found that the edge angle affects the polarity of nanoribbons with hydrogenated edges.

  8. Textbook Multigrid Efficiency for Leading Edge Stagnation

    NASA Technical Reports Server (NTRS)

    Diskin, Boris; Thomas, James L.; Mineck, Raymond E.

    2004-01-01

    A multigrid solver is defined as having textbook multigrid efficiency (TME) if the solutions to the governing system of equations are attained in a computational work which is a small (less than 10) multiple of the operation count in evaluating the discrete residuals. TME in solving the incompressible inviscid fluid equations is demonstrated for leading- edge stagnation flows. The contributions of this paper include (1) a special formulation of the boundary conditions near stagnation allowing convergence of the Newton iterations on coarse grids, (2) the boundary relaxation technique to facilitate relaxation and residual restriction near the boundaries, (3) a modified relaxation scheme to prevent initial error amplification, and (4) new general analysis techniques for multigrid solvers. Convergence of algebraic errors below the level of discretization errors is attained by a full multigrid (FMG) solver with one full approximation scheme (F.4S) cycle per grid. Asymptotic convergence rates of the F.4S cycles for the full system of flow equations are very fast, approaching those for scalar elliptic equations.

  9. Textbook Multigrid Efficiency for Leading Edge Stagnation

    NASA Technical Reports Server (NTRS)

    Diskin, Boris; Thomas, James L.; Mineck, Raymond E.

    2004-01-01

    A multigrid solver is defined as having textbook multigrid efficiency (TME) if the solutions to the governing system of equations are attained in a computational work which is a small (less than 10) multiple of the operation count in evaluating the discrete residuals. TME in solving the incompressible inviscid fluid equations is demonstrated for leading-edge stagnation flows. The contributions of this paper include (1) a special formulation of the boundary conditions near stagnation allowing convergence of the Newton iterations on coarse grids, (2) the boundary relaxation technique to facilitate relaxation and residual restriction near the boundaries, (3) a modified relaxation scheme to prevent initial error amplification, and (4) new general analysis techniques for multigrid solvers. Convergence of algebraic errors below the level of discretization errors is attained by a full multigrid (FMG) solver with one full approximation scheme (FAS) cycle per grid. Asymptotic convergence rates of the FAS cycles for the full system of flow equations are very fast, approaching those for scalar elliptic equations.

  10. Potential magnetic properties of nanotubes ( n, 0) with Klein and Fujita edges

    NASA Astrophysics Data System (ADS)

    Luhavaya, H. M.; Pavlov, M. V.; Ermilov, A. Yu.; Stepanov, N. F.

    2012-08-01

    Analytical solutions for localized states of zigzag-type nanotube (NT) fragments with various combinations of Klein and Fujita borders are considered using the Hückel approach. It is shown that the equations for determining molecular orbitals (MOs) in systems with two Klein edges are similar to equations for systems with two Fujita edges. An analytical formula for the energies of all π MOs is obtained for systems that have a Klein edge on one side and a Fujita edge on the other. It is established that these systems have n orbitals with energy α that are localized on the Fujita and Klein edges in dependence on the MO symmetry. The degeneracy of edge orbitals indicates that there is a tendency toward single occupancy of them and to the appearance of spin (magnetic) properties. In addition, the energies of the states of different multiplicity for NT fragments (8, 0) are calculated using the CASSCF approach. It is shown that the ground state has a multiplicity of 9, as was also indicated by estimates obtained using the density functional method (B3LYP). It is concluded that zigzag-type NTs with asymmetric edges have a tendency to exhibit spin properties. It is noted that the construction of nanoscale magnetic materials based on them is very promising.

  11. Uncertainty quantification in kinematic wave models

    SciTech Connect

    Wang, Peng; Tartakovsky, Daniel M.

    2012-10-01

    We developed a probabilistic approach to quantify parametric uncertainty in first-order hyperbolic conservation laws (kinematic wave equations). The approach relies on the derivation of a deterministic equation for the cumulative density function (CDF) of the system state, in which probabilistic descriptions (probability density functions or PDFs) of the system parameters and/or initial and boundary conditions serve as inputs. In contrast to PDF equations, which are often used in other contexts, CDF equations allow for straightforward and unambiguous determination of boundary conditions with respect to sample variables.The accuracy and robustness of solutions of the CDF equation for one such system, the Saint-Venant equations of river flows, were investigated via comparison with Monte Carlo simulations.

  12. Kinematic tests of exotic flat cosmological models

    NASA Technical Reports Server (NTRS)

    Charlton, Jane C.; Turner, Michael S.

    1987-01-01

    Theoretical prejudice and inflationary models of the very early universe strongly favor the flat, Einstein-de Sitter model of the universe. At present the observational data conflict with this prejudice. This conflict can be resolved by considering flat models of the universe which posses a smooth component of energy density. The kinematics of such models, where the smooth component is relativistic particles, a cosmological term, a network of light strings, or fast-moving, light strings is studied in detail. The observational tests which can be used to discriminate between these models are also discussed. These tests include the magnitude-redshift, lookback time-redshift, angular size-redshift, and comoving volume-redshift diagrams and the growth of density fluctuations.

  13. Kinematic tests of exotic flat cosmological models

    SciTech Connect

    Charlton, J.C.; Turner, M.S.

    1987-02-01

    Theoretical prejudice and inflationary models of the very early universe strongly favor the flat, Einstein-de Sitter model of the universe. At present the observational data conflict with this prejudice. This conflict can be resolved by considering flat models of the universe which posses a smooth component of energy density. The kinematics of such models, where the smooth component is relativistic particles, a cosmological term, a network of light strings, or fast-moving, light strings is studied in detail. The observational tests which can be used to discriminate between these models are also discussed. These tests include the magnitude-redshift, lookback time-redshift, angular size-redshift, and comoving volume-redshift diagrams and the growth of density fluctuations. 58 references.

  14. Deriving CME kinematics from multipoint space observations

    NASA Astrophysics Data System (ADS)

    Mrotzek, Niclas; Pluta, Adam; Bothmer, Volker; Davies, Jackie; Harrison, Richard

    2016-04-01

    It is commonly believed that the kinematics of CMEs consist of an early Lorentz acceleration phase near the Sun followed by a decelerating drag-force phase at distances further out. To better understand the physical processes of CME evolution, and also to predict more accurately their arrival times at other heliospheric locations, we have analysed CMEs using multipoint coronagraph observations from STEREO and SOHO. The CME speed evolution is analysed by applying time-series GCS-modelling. The analysis is extended to distances further away from the Sun through analysis of observations from the STEREO heliospheric imagers. The results are compared to those obtained from the geometrical modelling of time-elongation profiles of CMEs extracted from J-maps. We discuss the implications of our results in the context of state-of-the-art space weather predictions. The studies are carried out in the EU FP7 project HELCATS (Heliospheric Cataloguing, Analysis and Techniques Service).

  15. Unraveling L_{n,k}: Grassmannian Kinematics

    SciTech Connect

    Kaplan, Jared; /SLAC

    2010-02-15

    It was recently proposed that the leading singularities of the S-Matrix of N = 4 super Yang-Mills theory arise as the residues of a contour integral over a Grassmannian manifold, with space-time locality encoded through residue theorems generalizing Cauchy's theorem to more than one variable. We provide a method to identify the residue corresponding to any leading singularity, and we carry this out explicitly for all leading singularities at tree level and one-loop. We also give several examples at higher loops, including all generic two-loop leading singularities and an interesting four-loop object. As an example we consider a 12-pt N{sup 4}MHV leading singularity at two loops that has a kinematic structure involving double square roots. Our analysis results in a simple picture for how the topological structure of loop graphs is reflected in various substructures within the Grassmannian.

  16. A digital videofluoroscopic technique for spine kinematics.

    PubMed

    Breen, A; Allen, R; Morris, A

    1989-01-01

    The kinematic behaviour of the vertebral segments under the influence of spinal injury and other mechanical problems is difficult to quantify in patients. This paper describes the use of a calibration model and human subjects to investigate the accuracy of a method for determining lumbar intervertebral rotations using images digitized from an image intensifier. The main influences were found to be observer error in marking co-ordinates, scaling of the image presented by the computer's monitor, distortion caused by out-of-plane images and loss of image quality as a result of scattered radiation from the soft tissues. The technique may be valuable in the light of its efficiency and low X-ray exposure to patients.

  17. Shear dynamo problem: Quasilinear kinematic theory.

    PubMed

    Sridhar, S; Subramanian, Kandaswamy

    2009-04-01

    Large-scale dynamo action due to turbulence in the presence of a linear shear flow is studied. Our treatment is quasilinear and kinematic but is nonperturbative in the shear strength. We derive the integrodifferential equation for the evolution of the mean magnetic field by systematic use of the shearing coordinate transformation and the Galilean invariance of the linear shear flow. For nonhelical turbulence the time evolution of the cross-shear components of the mean field does not depend on any other components excepting themselves. This is valid for any Galilean-invariant velocity field, independent of its dynamics. Hence the shear-current assisted dynamo is essentially absent, although large-scale nonhelical dynamo action is not ruled out.

  18. Robot Calibration Using Iteration and Differential Kinematics

    NASA Astrophysics Data System (ADS)

    Ye, S. H.; Wang, Y.; Ren, Y. J.; Li, D. K.

    2006-10-01

    In the applications of seam laser tracking welding robot and general measuring robot station based on stereo vision, the robot calibration is the most difficult step during the whole system calibration progress. Many calibration methods were put forward, but the exact location of base frame has to be known no matter which method was employed. However, the accurate base frame location is hard to be known. In order to obtain the position of base coordinate, this paper presents a novel iterative algorithm which can also get parameters' deviations at the same time. It was a method of employing differential kinematics to solve link parameters' deviations and approaching real values step-by-step. In the end, experiment validation was provided.

  19. Differential Kinematics Of Contemporary Industrial Robots

    NASA Astrophysics Data System (ADS)

    Szkodny, T.

    2014-08-01

    The paper presents a simple method of avoiding singular configurations of contemporary industrial robot manipulators of such renowned companies as ABB, Fanuc, Mitsubishi, Adept, Kawasaki, COMAU and KUKA. To determine the singular configurations of these manipulators a global form of description of the end-effector kinematics was prepared, relative to the other links. On the basis of this description , the formula for the Jacobian was defined in the end-effector coordinates. Next, a closed form of the determinant of the Jacobian was derived. From the formula, singular configurations, where the determinant's value equals zero, were determined. Additionally, geometric interpretations of these configurations were given and they were illustrated. For the exemplary manipulator, small corrections of joint variables preventing the reduction of the Jacobian order were suggested. An analysis of positional errors, caused by these corrections, was presented

  20. Relativistic kinematics for motion faster than light

    NASA Technical Reports Server (NTRS)

    Jones, R. T.

    1982-01-01

    The use of conformal coordinates in relativistic kinematics is illustrated and a simple extension of the theory of motions faster than light is provided. An object traveling at a speed greater than light discloses its presence by appearing suddenly at a point, splitting into two apparent objects which then recede from each other at sublight velocities. According to the present theory motion at speeds faster than light would not benefit a space traveler, since the twin paradox becomes inverted at such speeds. In Einstein's theory travel at the velocity of light in an intertial system is equivalent to infinite velocity for the traveler. In the present theory the converse is also true; travel at infinite velocity is equivalent to the velocity of light for the traveler.

  1. Kinematic tests of exotic flat cosmological models

    SciTech Connect

    Charlton, J.C.; Turner, M.S.

    1986-05-01

    Theoretical prejudice and inflationary models of the very early Universe strongly favor the flat, Einstein-deSitter model of the Universe. At present the observational data conflict with this prejudice. This conflict can be resolved by considering flat models of the Universe which possess a smooth component by energy density. We study in detail the kinematics of such models, where the smooth component is relativistic particles, a cosmological term, a network of light strings, or fast-moving, light strings. We also discuss the observational tests which can be used to discriminate between these models. These tests include the magnitude-redshift, lookback time-redshift, angular size-redshift, and comoving volume-redshift diagrams and the growth of density fluctuations.

  2. Top quark kinematics and mass determination

    SciTech Connect

    Williams, H.H.

    1994-10-01

    An analysis is presented of 10 W + {ge} 3 jet events, each with evidence for the presence of a b quark, that were recently observed by the CDF collaboration. Seven of these events include a fourth jet and can be explicitly reconstructed as t{bar t} production. The best estimate of the top quark mass is M{sub t} = 174 {+-} 10{sub {minus}12}{sup +13} GeV/c{sup 2}. A study has also been performed to see if the kinematical properties of events with W + {ge} 3 jets gives evidence for top production. An excess of events with large jet energies, compared to that expected from direct production of W + {ge} 3 jets, is observed. A large fraction of these events also contain a b-quark and a fourth jet.

  3. Global and regional kinematics from SLR stations

    NASA Technical Reports Server (NTRS)

    Dunn, Peter J.

    1994-01-01

    The stations of the Global Laser Tracking Network have significantly contributed to the measurement of plate kinematics. The expanding network of progressively improved instruments clearly demonstrates the systems' centimeter positioning accuracy. Several satellite laser ranging (SLR) analysis groups have adopted techniques to distill geodynamic information from the Lageos-1 satellite observations using orbital arc lengths from an hour to a decade. SLR observations now provide the scale for the International Terrestrial Reference System and help to define the Earth's polar motion in this system. Agreement between positions separately determined with SLR, VLBI and GPS systems has been established at the level of a few centimeters in position and a few millimeters per year in horizontal velocity.

  4. Kinematic analysis of Toxoplasma gondii motility.

    PubMed

    Frixione, E; Mondragón, R; Meza, I

    1996-01-01

    Toxoplasma gondii tachyzoites execute a complex and little understood combination of rapid movements to reach and penetrate human or other animals cells. In the present study, computer-assisted simulation was used to quantitatively analyze the motility of these parasites in three-dimensional space with spatial and temporal resolutions in the micrometer and subsecond ranges. A digital model based on electron-micrographs of a serially sectioned tachyzoite was animated according to a videomicrographed sequence of a characteristic repetitive movement. Keyframe animation defined over 150 frames by a total of 36 kinematic parameters for specific motions, of both the whole model and particular domains, resulted in a real-time life-like simulation of the videorecorded tachyzoite movement. The kinematic values indicate that a full revolution of the model is composed of three half-turns accomplished in nearly 5 s with two phases: a relatively slow 180 degrees tilting with regard to the substratum plane, followed by fast (over 200 degrees/s) spinning almost simultaneous with pivoting around the posterior end, each clockwise and for about 180 degrees. Maximal flexing of the body, as well as bowing and retraction of its anterior end, occur at midway during the tilting phase. An estimated 70 degrees. clockwise torsion of the body seems to precede the spinning-pivoting phase. The results suggest the operation of two basic forces in the motility of T. gondii tachyzoites: (1) a clockwise torque that causes torsion, spinning, and pivoting; and (2) a longitudinal pull that contracts, bends and tilts the parasite. We discuss the possibility that both of these forces might result from the action of an actin-myosin system enveloping the twisted framework of microtubules characteristic of these organisms.

  5. Kinematics of Visually-Guided Eye Movements

    PubMed Central

    Hess, Bernhard J. M.; Thomassen, Jakob S.

    2014-01-01

    One of the hallmarks of an eye movement that follows Listing’s law is the half-angle rule that says that the angular velocity of the eye tilts by half the angle of eccentricity of the line of sight relative to primary eye position. Since all visually-guided eye movements in the regime of far viewing follow Listing’s law (with the head still and upright), the question about its origin is of considerable importance. Here, we provide theoretical and experimental evidence that Listing’s law results from a unique motor strategy that allows minimizing ocular torsion while smoothly tracking objects of interest along any path in visual space. The strategy consists in compounding conventional ocular rotations in meridian planes, that is in horizontal, vertical and oblique directions (which are all torsion-free) with small linear displacements of the eye in the frontal plane. Such compound rotation-displacements of the eye can explain the kinematic paradox that the fixation point may rotate in one plane while the eye rotates in other planes. Its unique signature is the half-angle law in the position domain, which means that the rotation plane of the eye tilts by half-the angle of gaze eccentricity. We show that this law does not readily generalize to the velocity domain of visually-guided eye movements because the angular eye velocity is the sum of two terms, one associated with rotations in meridian planes and one associated with displacements of the eye in the frontal plane. While the first term does not depend on eye position the second term does depend on eye position. We show that compounded rotation - displacements perfectly predict the average smooth kinematics of the eye during steady- state pursuit in both the position and velocity domain. PMID:24751602

  6. A kinematic study of finswimming at surface.

    PubMed

    Gautier, Jimmy; Baly, Laurent; Zanone, Pier-Giorgio; Watier, Bruno

    2004-06-01

    Finswimming is a sport of speed practiced on the surface or underwater, in which performance is based on whole-body oscillations. The present study investigated the undulatory motion performed by finswimmers at the surface. This study aiming to analyze the influence of the interaction of gender, practice level, and race distance on selected kinematic parameters. Six elite and six novices finswimmers equipped with joints markers (wrist, elbow, shoulder, hip, knee, and ankle) were recorded in the sagittal plane. The position of these anatomical marks was digitized at 50 Hz. An automated motion analysis software yielded velocity, vertical amplitude, frequency, and angular position. Results showed that stroke frequency decreased whereas the mean amplitude of all joints increased with increasing race distance (p < 0.01). Mean joint amplitude for the upper limbs (wrist, elbow and shoulder) was smaller for experts than for novices. Whereas that of the ankle was larger, so that the oscillation amplitude increased from shoulder to ankle. Elite male finswimmers were pitching more acutely than female. Moreover, elite male finswimmers showed a smaller knee bending than novices and than elite females (p < 0.01). This indicated that elite male finswimmers attempt to reduce drag forces thanks to a weak knee bending and a low upper limbs pitch. To sum up, gender, expertise, and race distance affect the performance and its kinematics in terms frontal drag. Expertise in finswimming requires taking advantage of the mechanical constraints pertaining to hydrodynamic constraints in order to optimize performance. Key PointsFinswimmers are at one and the same time a propelling and a propelled body. This study investigates the undulatory motion performed by finswimmers at the surface.Elite male finswimmers were pitching more acutely than female swimmers and showed a smaller knee bending than both novices and elite female swimmers.Finswimmers tended to perform a dolphin-like motion, which

  7. Kinematics of Hα Emitting Stars in Andromeda

    NASA Astrophysics Data System (ADS)

    Ilango, Megha; Ilango, Anita; Damon, Gabriel; Prichard, Laura; Guhathakurta, Puragra; PHAT Collaboration; SPLASH Collaboration

    2017-01-01

    Studying emission line stars helps improve our understanding of stellar evolution, types of stars, and their environments. In this study, we analyzed stars exhibiting Hα emission (Hα stars) in the Andromeda Galaxy. We used a combination of spectroscopic and photometric diagnostic methods to remove a population of foreground Milky Way (MW) star contaminants from our data set. The Hα stars were selected from a sample of 5295 spectra from the Spectroscopic and Photometric Landscape of Andromeda’s Stellar Halo (SPLASH) survey and accompanying photometric data from the Panchromatic Hubble Andromeda Treasury (PHAT) survey. Velocities of two classes of Hα stars, main sequence (MS) stars and asymptotic giant branch (AGB) stars, were analyzed through a novel Age-Velocity Difference Correlation (AVDC) method, which utilizes line-of-sight velocity differences (LOSVDs) in order to estimate the age of a rare stellar population. Histograms, weighted means, and weighted standard deviations of the LOSVDs were used to conclude that MS stars are more kinematically coherent than AGB stars, and that Hα stars are kinematically comparable and thus close in age to their non-Hα counterparts. With these results, it can definitively be inferred that mass loss is important in two stages of stellar evolution: massive MS and intermediate mass AGB. We hypothesized that this mass loss could either occur as a normal part of MS and AGB evolution, or that it could be emitted by only a subpopulation of MS and AGB stars throughout their life cycle. Our use of the novel AVDC method sets a precedent for the use of similar methods in predicting the ages of rare stellar subgroups.This research was supported by NASA and the National Science Foundation. Most of this work was carried out by high school students working under the auspices of the Science Internship Program at UC Santa Cruz.

  8. Coulomb edge effects in graphene nanoribbons

    NASA Astrophysics Data System (ADS)

    Jaskolski, W.; Ayuela, A.

    2014-10-01

    Coulomb effects in graphene nanoribbons with arbitrary edges are investigated with the use of a mean-field Hubbard model. It was recently shown that chiral ribbons with minimal edges, characterized by the translation vector (n,m), have a similar structure of bands localized around the Fermi energy as pure zigzag ribbons (n-m,0). Here we show that these flat bands in both ribbon cases differ in detail due to the perturbation induced by armchair edge nodes. For chiral ribbons the edge bands split at the zone boundary, where the corresponding bands of (n-m,0) zigzag ribbons are degenerate. Coulomb interactions enhance strongly this splitting and at the same time they bring spin into play. We modify each edge keeping global sublattice balance to find that spin degeneracy can be partially lifted. The breaking of spin-degeneracy depends on the asymmetry between the edges and in some cases leads to spin-polarized currents.

  9. Kinematics of nonlinearly interacting MHD instabilities in a plasma

    NASA Astrophysics Data System (ADS)

    Hansen, Alexander Karl

    2000-10-01

    In reversed-field pinch (RFP) plasmas several tearing instabilities (modes) are simultaneously active, and are of large amplitude. Theory predicts that in addition to interacting linearly with magnetic perturbations from outside the plasma, such as field errors or a resistive wall, the modes in the RFP can interact nonlinearly with each other through a three-wave interaction. In the current work investigations of both the linear (external) and nonlinear contributions to the kinematics of the tearing modes in the Madison Symmetric Torus (MST) RFP are reported. Theory predicts that tearing modes will respond only to magnetic perturbations that are spatially resonant with them. The results in this work verified that the theory is applicable to the RFP, in spite of its more complicated magnetic mode structure, involving perturbations of a single poloidal mode number, i.e. that affected multiple modes simultaneously. However, for perturbations of a single toroidal mode number, i.e. resonant with only one mode, it was found that multiple modes were simultaneously affected. Three pieces of evidence were found that indicated experimentally the existence of nonlinear torques in MST. It was found that when the rotation profile was shifted by an applied electric field such that these modes rotated in the opposite direction to normal, episodic accelerations in the rotation were in the same direction as in standard discharges. In addition, when one of the modes that is required for the three-wave nonlinear interaction was removed from the plasma, the large changes in the mode velocity disappeared. Finally, the correlated triple products characteristic of the nonlinear torque were measured, and they were found only to be in the right phase to produce a torque during the sawtooth events.

  10. Differences in Lower Extremity and Trunk Kinematics between Single Leg Squat and Step Down Tasks

    PubMed Central

    Lewis, Cara L.; Foch, Eric; Luko, Marc M.; Loverro, Kari L.; Khuu, Anne

    2015-01-01

    The single leg squat and single leg step down are two commonly used functional tasks to assess movement patterns. It is unknown how kinematics compare between these tasks. The purpose of this study was to identify kinematic differences in the lower extremity, pelvis and trunk between the single leg squat and the step down. Fourteen healthy individuals participated in this research and performed the functional tasks while kinematic data were collected for the trunk, pelvis, and lower extremities using a motion capture system. For the single leg squat task, the participant was instructed to squat as low as possible. For the step down task, the participant was instructed to stand on top of a box, slowly lower him/herself until the non-stance heel touched the ground, and return to standing. This was done from two different heights (16cm and 24cm). The kinematics were evaluated at peak knee flexion as well as at 60° of knee flexion. Pearson correlation coefficients (r) between the angles at those two time points were also calculated to better understand the relationship between each task. The tasks resulted in kinematics differences at the knee, hip, pelvis, and trunk at both time points. The single leg squat was performed with less hip adduction (p ≤ 0.003), but more hip external rotation and knee abduction (p ≤ 0.030), than the step down tasks at 60° of knee flexion. These differences were maintained at peak knee flexion except hip external rotation was only significant in the 24cm step down task (p ≤ 0.029). While there were multiple differences between the two step heights at peak knee flexion, the only difference at 60° of knee flexion was in trunk flexion (p < 0.001). Angles at the knee and hip had a moderate to excellent correlation (r = 0.51–0.98), but less consistently so at the pelvis and trunk (r = 0.21–0.96). The differences in movement patterns between the single leg squat and the step down should be considered when selecting a single leg task

  11. Differences in Lower Extremity and Trunk Kinematics between Single Leg Squat and Step Down Tasks.

    PubMed

    Lewis, Cara L; Foch, Eric; Luko, Marc M; Loverro, Kari L; Khuu, Anne

    2015-01-01

    The single leg squat and single leg step down are two commonly used functional tasks to assess movement patterns. It is unknown how kinematics compare between these tasks. The purpose of this study was to identify kinematic differences in the lower extremity, pelvis and trunk between the single leg squat and the step down. Fourteen healthy individuals participated in this research and performed the functional tasks while kinematic data were collected for the trunk, pelvis, and lower extremities using a motion capture system. For the single leg squat task, the participant was instructed to squat as low as possible. For the step down task, the participant was instructed to stand on top of a box, slowly lower him/herself until the non-stance heel touched the ground, and return to standing. This was done from two different heights (16 cm and 24 cm). The kinematics were evaluated at peak knee flexion as well as at 60° of knee flexion. Pearson correlation coefficients (r) between the angles at those two time points were also calculated to better understand the relationship between each task. The tasks resulted in kinematics differences at the knee, hip, pelvis, and trunk at both time points. The single leg squat was performed with less hip adduction (p ≤ 0.003), but more hip external rotation and knee abduction (p ≤ 0.030), than the step down tasks at 60° of knee flexion. These differences were maintained at peak knee flexion except hip external rotation was only significant in the 24 cm step down task (p ≤ 0.029). While there were multiple differences between the two step heights at peak knee flexion, the only difference at 60° of knee flexion was in trunk flexion (p < 0.001). Angles at the knee and hip had a moderate to excellent correlation (r = 0.51-0.98), but less consistently so at the pelvis and trunk (r = 0.21-0.96). The differences in movement patterns between the single leg squat and the step down should be considered when selecting a single leg task

  12. Kinematic models of the upper limb joints for multibody kinematics optimisation: An overview.

    PubMed

    Duprey, Sonia; Naaim, Alexandre; Moissenet, Florent; Begon, Mickaël; Chèze, Laurence

    2016-12-09

    Soft tissue artefact (STA), i.e. the motion of the skin, fat and muscles gliding on the underlying bone, may lead to a marker position error reaching up to 8.7cm for the particular case of the scapula. Multibody kinematics optimisation (MKO) is one of the most efficient approaches used to reduce STA. It consists in minimising the distance between the positions of experimental markers on a subject skin and the simulated positions of the same markers embedded on a kinematic model. However, the efficiency of MKO directly relies on the chosen kinematic model. This paper proposes an overview of the different upper limb models available in the literature and a discussion about their applicability to MKO. The advantages of each joint model with respect to its biofidelity to functional anatomy are detailed both for the shoulder and the forearm areas. Models capabilities of personalisation and of adaptation to pathological cases are also discussed. Concerning model efficiency in terms of STA reduction in MKO algorithms, a lack of quantitative assessment in the literature is noted. In priority, future studies should concern the evaluation and quantification of STA reduction depending on upper limb joint constraints.

  13. [Artificial crowns influence upon edge parodontium status].

    PubMed

    Zhulev, E N; Serov, A B

    2010-01-01

    With the aim of prosthetic treatment efficacy increase study of edge parodontium tissue reaction upon different types of artificial crowns was done and methods of chronic localized parodontitis prevention were developed. Changes of the main gingival fluid characteristics (amount, acidity, interleukine-1beta concentration) and indicators of microcirculation in edge parodontium of the teeth under the artificial crowns influence were disclosed. There were developed methods of chronic localized parodontitis prevention produced by artificial crowns edge.

  14. Constrained Kinematics of ICMEs from Multi-point in Situ and Heliospheric Imaging Data

    NASA Astrophysics Data System (ADS)

    Rollett, T.; Temmer, M.; Moestl, C.; Veronig, A. M.; Lugaz, N.; Vrsnak, B.; Farrugia, C. J.; Amerstorfer, U.

    2013-12-01

    The constrained harmonic mean (CHM) method is used to calculate the direction of motion of ICMEs and their kinematical profiles. Combining single spacecraft white-light observations from STEREO/HI with supplementary in situ data, it is possible to derive the propagation speed varying with heliocentric distance. This is a big advantage against other single-viewpoint methods, i.e. fitting methods, which assume a constant propagation speed. We show two different applications for the CHM method: first, an analysis of the interaction between the solar wind and ICMEs, and second, the interaction between two ICMEs. For analyzing interaction processes it is crucial to use a method that has the ability to investigate the corresponding effects on ICME kinematics. Additionally, we show the analysis of an outstanding fast ICME event of March 2012, which was detected in situ by Venus Express, Messenger and Wind and also observed by STEREO-A/HI. Due to these multiple in situ measurements it was possible to constrain the ICME kinematics by three different boundary values. These studies are fundamental in order to deepen the understanding of ICME evolution and to enhance existing forecasting methods. This work has received funding from the European Commission FP7 Project COMESEP (263252).

  15. Ionized gas kinematics of galaxies in the CALIFA survey. I. Velocity fields, kinematic parameters of the dominant component, and presence of kinematically distinct gaseous systems

    NASA Astrophysics Data System (ADS)

    García-Lorenzo, B.; Márquez, I.; Barrera-Ballesteros, J. K.; Masegosa, J.; Husemann, B.; Falcón-Barroso, J.; Lyubenova, M.; Sánchez, S. F.; Walcher, J.; Mast, D.; García-Benito, R.; Méndez-Abreu, J.; van de Ven, G.; Spekkens, K.; Holmes, L.; Monreal-Ibero, A.; del Olmo, A.; Ziegler, B.; Bland-Hawthorn, J.; Sánchez-Blázquez, P.; Iglesias-Páramo, J.; Aguerri, J. A. L.; Papaderos, P.; Gomes, J. M.; Marino, R. A.; González Delgado, R. M.; Cortijo-Ferrero, C.; López-Sánchez, A. R.; Bekeraitė, S.; Wisotzki, L.; Bomans, D.

    2015-01-01

    Context. Ionized gas kinematics provide important clues to the dynamical structure of galaxies and hold constraints to the processes driving their evolution. Aims: The motivation of this work is to provide an overall characterization of the kinematic behavior of the ionized gas of the galaxies included in the Calar Alto Legacy Integral field Area (CALIFA), offering kinematic clues to potential users of the CALIFA survey for including kinematical criteria in their selection of targets for specific studies. From the first 200 galaxies observed by CALIFA survey in its two configurations, we present the two-dimensional kinematic view of the 177 galaxies satisfaying a gas content/detection threshold. Methods: After removing the stellar contribution, we used the cross-correlation technique to obtain the radial velocity of the dominant gaseous component for each spectrum in the CALIFA data cubes for different emission lines (namely, [O ii] λλ3726,3729, [O iii] λλ4959,5007, Hα+[N ii] λλ6548,6584, and [SII]λλ6716,6730). The main kinematic parameters measured on the plane of the sky were directly derived from the radial velocities with no assumptions on the internal prevailing motions. Evidence of the presence of several gaseous components with different kinematics were detected by using [O iii] λλ4959,5007 emission line profiles. Results: At the velocity resolution of CALIFA, most objects in the sample show regular velocity fields, although the ionized-gas kinematics are rarely consistent with simple coplanar circular motions. Thirty-five percent of the objects present evidence of a displacement between the photometric and kinematic centers larger than the original spaxel radii. Only 17% of the objects in the sample exhibit kinematic lopsidedness when comparing receding and approaching sides of the velocity fields, but most of them are interacting galaxies exhibiting nuclear activity (AGN or LINER). Early-type (E+S0) galaxies in the sample present clear

  16. Modelling of edge localised modes and edge localised mode control

    SciTech Connect

    Huijsmans, G. T. A.; Loarte, A.; Chang, C. S.; Ferraro, N.; Sugiyama, L.; Waelbroeck, F.; Xu, X. Q.; Futatani, S.

    2015-02-15

    Edge Localised Modes (ELMs) in ITER Q = 10 H-mode plasmas are likely to lead to large transient heat loads to the divertor. To avoid an ELM induced reduction of the divertor lifetime, the large ELM energy losses need to be controlled. In ITER, ELM control is foreseen using magnetic field perturbations created by in-vessel coils and the injection of small D2 pellets. ITER plasmas are characterised by low collisionality at a high density (high fraction of the Greenwald density limit). These parameters cannot simultaneously be achieved in current experiments. Therefore, the extrapolation of the ELM properties and the requirements for ELM control in ITER relies on the development of validated physics models and numerical simulations. In this paper, we describe the modelling of ELMs and ELM control methods in ITER. The aim of this paper is not a complete review on the subject of ELM and ELM control modelling but rather to describe the current status and discuss open issues.

  17. HALOGAS: H I OBSERVATIONS AND MODELING OF THE NEARBY EDGE-ON SPIRAL GALAXY NGC 4244

    SciTech Connect

    Zschaechner, Laura K.; Rand, Richard J.; Heald, George H.; Gentile, Gianfranco; Kamphuis, Peter E-mail: rjr@phys.unm.edu E-mail: Gianfranco.Gentile@ugent.be

    2011-10-10

    We present 21 cm observations and models of the H I kinematics and distribution of NGC 4244, a nearby edge-on Scd galaxy observed as part of the Westerbork HALOGAS (Hydrogen Accretion in LOcal GAlaxieS) survey. Our models give insight into the H I kinematics and distribution with an emphasis on the potential existence of extraplanar gas as well as a negative gradient in rotational velocity with height above the plane of the disk (a lag). Our models yield strong evidence against a significantly extended halo and instead favor a warp component along the line of sight as an explanation for most of the observed thickening of the disk. Based on these models, we detect a lag of -9{sup +3}{sub -2} km s{sup -1} kpc{sup -1} in the approaching half and -9 {+-} 2 km s{sup -1} kpc{sup -1} in the receding half. This lag decreases in magnitude to -5 {+-} 2 km s{sup -1} kpc{sup -1} and -4 {+-} 2 km s{sup -1} kpc{sup -1} near a radius of 10 kpc in the approaching and receding halves, respectively. Additionally, we detect several distinct morphological and kinematic features including a shell that is probably driven by star formation within the disk.

  18. An edge index for topological insulators

    NASA Astrophysics Data System (ADS)

    Prodan, Emil

    2009-03-01

    Topological insulators display dissipationless currents flowing at the edges of the samples. These currents are associated to chiral edge modes, whose existence is intrinsically linked to the topology of the electronic states of the bulk. The edge modes can be easily investigated when the edges are smooth and have a periodicity, but as soon as the periodicity is absent, the problem becomes un-traceable by purely theoretical means. In my talk I will exemplify the use of non-commutative calculus to explore the properties, especially the stability of the edge modes. For example, using such techniques one can give a fairly elementary proof that the edge modes in Chern insulators survive even for a rough (random) edge. Similarly, for the Spin-Hall effect, one can define an observable and its associated current whose conductance remains quantized during various deformations of the Hamiltonian system. It turns out that in all cases, the edge conductance is given by the index of a Fredholm operator, which provides a new topological invariant linked directly to the edge rather than the bulk.

  19. Moveable Leading Edge Device for a Wing

    NASA Technical Reports Server (NTRS)

    Pitt, Dale M. (Inventor); Eckstein, Nicholas Stephen (Inventor)

    2013-01-01

    A method and apparatus for managing a flight control surface system. A leading edge section on a wing of an aircraft is extended into a deployed position. A deformable section connects the leading edge section to a trailing section. The deformable section changes from a deformed shape to an original shape when the leading edge section is moved into the deployed position. The leading edge section on the wing is moved from the deployed position to an undeployed position. The deformable section changes to the deformed shape inside of the wing.

  20. Edge Segment-Based Automatic Video Surveillance

    NASA Astrophysics Data System (ADS)

    Hossain, M. Julius; Dewan, M. Ali Akber; Chae, Oksam

    2007-12-01

    This paper presents a moving-object segmentation algorithm using edge information as segment. The proposed method is developed to address challenges due to variations in ambient lighting and background contents. We investigated the suitability of the proposed algorithm in comparison with the traditional-intensity-based as well as edge-pixel-based detection methods. In our method, edges are extracted from video frames and are represented as segments using an efficiently designed edge class. This representation helps to obtain the geometric information of edge in the case of edge matching and moving-object segmentation; and facilitates incorporating knowledge into edge segment during background modeling and motion tracking. An efficient approach for background initialization and robust method of edge matching is presented, to effectively reduce the risk of false alarm due to illumination change and camera motion while maintaining the high sensitivity to the presence of moving object. Detected moving edges are utilized along with watershed algorithm for extracting video object plane (VOP) with more accurate boundary. Experiment results with real image sequence reflect that the proposed method is suitable for automated video surveillance applications in various monitoring systems.

  1. Study on edge extracting in noise image

    NASA Astrophysics Data System (ADS)

    Feng, Gui; Lin, Qiwei; Fu, QingQing

    2008-03-01

    In order to reduce the influence of noise on edge extracting and improve the precision of edge localization on the image, after analyzed the principle, strong points and short points of some traditional edge detecting methods, an effective algorithm for edge extracting in noise image was proposed in this paper. Adopting thought of traditional multi-directional and multistage combinational filtering, an image detail-preserving adaptive filter is designed to remove noise, and then extract the edge in the image. On the basis of the classical Sobel operator, we introduced an algorithm with resisting noise, good real-time and locating accurate edge. The algorithm can distinguish real edge from noise in terms of the theory of successive and smooth edge and random noise. The algorithm was accomplished under visual C++ 6.0 environment and tested by several standard images. The experimental result prove that the presented method is feasible and effective when the salt-pepper pollution of image is smaller than 15%, furthermore the method can extract edges with high location precision and good continuity accurately and effectively, at the same time, it has high processing speed.

  2. Edge mode spectroscopy and imaging for film edge properties in magnetic nanostructures

    NASA Astrophysics Data System (ADS)

    McMichael, Robert

    2014-03-01

    Lithography is an act of violence. Often, films are almost entirely obliterated by patterning, leaving only nanostructures behind with film edges that have borne the brunt of the damage, edges that carry with them the scars of energetic ion bombardment, reactive ions, liftoff and exposure to ambient conditions. In this talk, I will present a variation on ferromagnetic resonance force microscopy that can provide insight into the magnetic properties of film edges in magnetic nanostructures. The method relies on the non-uniformity of the magnetic field in patterned-film nanostructures that are magnetized in-plane, specifically, the low-field regions that form near where the magnetization is directed normal to the edge. In these regions, localized precession forms as trapped spin wave modes, and the resonance condition of these modes serves as an indicator of the edge properties. I will present modeling and measurements on a 500 nm diameter, 25 nm thick Permalloy disk to illustrate the method. Micromagnetic modeling of this disk predicts a main mode that is nearly uniform across the sample and three localized edge modes with higher resonance fields. The spectra measured with various tip positions and mode imaging are consistent with the modeling results. In addition to a strong center mode, three distinct edge modes are observed when the tip is near the disk edge. For a symmetric disk, the modeling predicts that the edge mode resonances are identical on the two opposite edges. However, the measured edge mode resonances on opposite edges of the disk are detected at different resonance fields, suggesting inhomogeneity of the edge properties. By rotating the applied field, we control the position of the localized edge mode along the edge of the disk and confirm that the edge mode resonance field has a strong angular dependence, showing that edge mode properties can vary significantly in a nominally circular disk.

  3. Exploring one aspect of pedagogical content knowledge of teaching assistants using the test of understanding graphs in kinematics

    NASA Astrophysics Data System (ADS)

    Maries, Alexandru; Singh, Chandralekha

    2013-12-01

    The Test of Understanding Graphs in Kinematics (TUG-K) is a multiple-choice test developed by Beichner in 1994 to assess students’ understanding of kinematics graphs. Many of the items on the TUG-K have strong distractor choices which correspond to students’ common difficulties with kinematics graphs. Instruction is unlikely to be effective if instructors do not know the common difficulties of introductory physics students and explicitly take them into account in their instructional design. We evaluate one aspect of the pedagogical content knowledge of first-year physics graduate students enrolled in a teaching assistant training course related to topics covered in the TUG-K. In particular, for each item on the TUG-K, the graduate students were asked to identify which incorrect answer choice they thought would be most commonly selected by introductory physics students if they did not know the correct answer after instruction in relevant concepts. We used the graduate student data and the data from Beichner’s original paper for introductory physics students (which was collected from over 500 college and high school students) to assess this aspect of the pedagogical content knowledge of the graduate students, i.e., knowledge of student difficulties related to kinematics graphs as they are revealed by the TUG-K. We find that, although the graduate students, on average, performed better than random guessing at identifying introductory student difficulties on the TUG-K, they did not identify many common difficulties that introductory students have with graphs in kinematics. In addition, we find that the ability of graduate students to identify the difficulties of introductory students is context dependent and that discussions among the graduate students improved their understanding of student difficulties related to kinematics graphs. Moreover, we find that the ability of American graduate students in identifying common student difficulties is comparable with that

  4. Efficient edge-guided full-waveform inversion by Canny edge detection and bilateral filtering algorithms

    NASA Astrophysics Data System (ADS)

    Xiang, Shiming; Zhang, Haijiang

    2016-11-01

    It is known full-waveform inversion (FWI) is generally ill-conditioned and various strategies including pre-conditioning and regularizing the inversion system have been proposed to obtain a reliable estimation of the velocity model. Here, we propose a new edge-guided strategy for FWI in frequency domain to efficiently and reliably estimate velocity models with structures of the size similar to the seismic wavelength. The edges of the velocity model at the current iteration are first detected by the Canny edge detection algorithm that is widely used in image processing. Then, the detected edges are used for guiding the calculation of FWI gradient as well as enforcing edge-preserving total variation (TV) regularization for next iteration of FWI. Bilateral filtering is further applied to remove noise but keep edges of the FWI gradient. The proposed edge-guided FWI in the frequency domain with edge-guided TV regularization and bilateral filtering is designed to preserve model edges that are recovered from previous iterations as well as from lower frequency waveforms when FWI is conducted from lower to higher frequencies. The new FWI method is validated using the complex Marmousi model that contains several steeply dipping fault zones and hundreds of horizons. Compared to FWI without edge guidance, our proposed edge-guided FWI recovers velocity model anomalies and edges much better. Unlike previous image-guided FWI or edge-guided TV regularization strategies, our method does not require migrating seismic data, thus is more efficient for real applications.

  5. Saturn's Rings Edge-on

    NASA Technical Reports Server (NTRS)

    1995-01-01

    In one of nature's most dramatic examples of 'now-you see-them, now-you-don't', NASA's Hubble Space Telescope captured Saturn on May 22, 1995 as the planet's magnificent ring system turned edge-on. This ring-plane crossing occurs approximately every 15 years when the Earth passes through Saturn's ring plane.

    For comparison, the top picture was taken by Hubble on December 1, 1994 and shows the rings in a more familiar configuration for Earth observers.

    The bottom picture was taken shortly before the ring plane crossing. The rings do not disappear completely because the edge of the rings reflects sunlight. The dark band across the middle of Saturn is the shadow of the rings cast on the planet (the Sun is almost 3 degrees above the ring plane.) The bright stripe directly above the ring shadow is caused by sunlight reflected off the rings onto Saturn's atmosphere. Two of Saturn's icy moons are visible as tiny starlike objects in or near the ring plane. They are, from left to right, Tethys (slightly above the ring plane) and Dione.

    This observation will be used to determine the time of ring-plane crossing and the thickness of the main rings and to search for as yet undiscovered satellites. Knowledge of the exact time of ring-plane crossing will lead to an improved determination of the rate at which Saturn 'wobbles' about its axis (polar precession).

    Both pictures were taken with Hubble's Wide Field Planetary Camera 2. The top image was taken in visible light. Saturn's disk appears different in the bottom image because a narrowband filter (which only lets through light that is not absorbed by methane gas in Saturn's atmosphere) was used to reduce the bright glare of the planet. Though Saturn is approximately 900 million miles away, Hubble can see details as small as 450 miles across.

    The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science

  6. Kinematic and dynamic modeling and approximate analysis of a roller chain drive

    NASA Astrophysics Data System (ADS)

    Fuglede, Niels; Thomsen, Jon Juel

    2016-03-01

    A simple roller chain drive consisting of two sprockets connected by tight chain spans is investigated. First, a kinematic model is presented which include both spans and sprockets. An approach for calculating the chain wrapping length is presented, which also allows for the exact calculation of sprocket center positions for a given chain length. The kinematic analysis demonstrates that the total length of the chain wrapped around the sprockets generally varies during one tooth period. Analytical predictions for the wrapping length are compared to multibody simulation results and show very good agreement. It is thereby demonstrated that chain drives with tight chain spans must include compliant components to function. Second, a dynamic model is presented which includes the two spans and the driven sprocket. Assuming the presence of a stationary operating state, the presented dynamic model allows for analytical studies of the coupled motion of the chain spans and driven sprocket. Parametric excitation of the spans come from sprocket angular displacements, and the driven sprocket acts as a boundary which can be compliant in the axial direction. External transverse excitation of the spans comes from polygonal action, and is treated through kinematic forcing at the moving string boundaries. Perturbation analysis of the model is carried out using the method of multiple scales. Results show a multitude of internal and external resonance conditions, and some examples are presented of both decoupled and coupled motion. Together, the kinematic and dynamic model are aimed toward providing a framework for conducting and understanding both numerical, and experimental investigations of roller chain drive dynamics.

  7. The high-ion content and kinematics of low-redshift Lyman limit systems

    SciTech Connect

    Fox, Andrew J.; Tumlinson, Jason; Bordoloi, Rongmon; Lehner, Nicolas; Howk, J. Christopher; Tripp, Todd M.; Katz, Neal; Prochaska, J. Xavier; Werk, Jessica K.; Oppenheimer, Benjamin D.; Davé, Romeel

    2013-12-01

    We study the high-ion content and kinematics of the circumgalactic medium around low-redshift galaxies using a sample of 23 Lyman limit systems (LLSs) at 0.08 < z < 0.93 observed with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. In Lehner et al., we recently showed that low-z LLSs have a bimodal metallicity distribution. Here we extend that analysis to search for differences between the high-ion and kinematic properties of the metal-poor and metal-rich branches. We find that metal-rich LLSs tend to show higher O VI columns and broader O VI profiles than metal-poor LLSs. The total H I line width (Δv {sub 90} statistic) in LLSs is not correlated with metallicity, indicating that the H I kinematics alone cannot be used to distinguish inflow from outflow and gas recycling. Among the 17 LLSs with O VI detections, all but two show evidence of kinematic sub-structure, in the form of O VI-H I centroid offsets, multiple components, or both. Using various scenarios for how the metallicities in the high-ion and low-ion phases of each LLS compare, we constrain the ionized hydrogen column in the O VI phase to lie in the range log N(H II) ∼ 17.6-20. The O VI phase of LLSs is a substantial baryon reservoir, with M(high-ion) ∼ 10{sup 8.5-10.9} (r/150 kpc){sup 2} M {sub ☉}, similar to the mass in the low-ion phase. Accounting for the O VI phase approximately doubles the contribution of low-z LLSs to the cosmic baryon budget.

  8. Monitoring the kinematic of active landslides with ALOS/PALSAR DInSAR processing.

    NASA Astrophysics Data System (ADS)

    Schlögel, Romy; Doubre, Cécile; Malet, Jean-Philippe

    2014-05-01

    This study targets the analysis of the kinematics of large active landslide through the interpretation of L-band ALOS/PALSAR interferograms. In mountainous areas, landslide monitoring with radar images is often difficult to interpret because of the complex topography, important changes in vapor content in the atmosphere, and the presence of highly variable surface states (vegetation, soil humidity, snow cover, superficial mass transfer). Sliding sub-units of two large and continuously active landslides (La Valette and Poche), exhibiting displacement rates ranging from 0.1 to 4.0 cm.day-1, are used as case studies to develop and explain the methodology. The results corresponding to positive or negative difference in phase value allow for the detection of landslide sub-units characterized by different kinematic patterns (e.g. single rotational slide, translational slide, multiple rotational slides). In the upper parts of the landslides, predominance of vertical displacements (subsidence) is observed in addition to a displacement in the downslope direction; this kinematic pattern is highlighted by either positive phase values corresponding to motion far away from the satellite. In the lower parts of the landslides, accumulation is observed in addition to a displacement in the downslope direction; this kinematic pattern is highlighted by negative phase values in the interferograms corresponding to motion toward the satellite. Extension of the landslides (downhill, uphill or laterally) is discussed according to geomorphological observations and a priori knowledge on the landslides. Quantitative measurements of the displacement are projected along the slope and the vertical components according to the observed landslide patterns. The InSAR displacements are in good agreement with on-site field measurements (permanent GNSS observations, GNSS campaigns on benchmarks, and terrestrial laser scanner surveys). Peaks in displacement rates are correlated to meteorological data.

  9. Multiple Core Galaxies

    NASA Technical Reports Server (NTRS)

    Miller, R.H.; Morrison, David (Technical Monitor)

    1994-01-01

    Nuclei of galaxies often show complicated density structures and perplexing kinematic signatures. In the past we have reported numerical experiments indicating a natural tendency for galaxies to show nuclei offset with respect to nearby isophotes and for the nucleus to have a radial velocity different from the galaxy's systemic velocity. Other experiments show normal mode oscillations in galaxies with large amplitudes. These oscillations do not damp appreciably over a Hubble time. The common thread running through all these is that galaxies often show evidence of ringing, bouncing, or sloshing around in unexpected ways, even though they have not been disturbed by any external event. Recent observational evidence shows yet another phenomenon indicating the dynamical complexity of central regions of galaxies: multiple cores (M31, Markarian 315 and 463 for example). These systems can hardly be static. We noted long-lived multiple core systems in galaxies in numerical experiments some years ago, and we have more recently followed up with a series of experiments on multiple core galaxies, starting with two cores. The relevant parameters are the energy in the orbiting clumps, their relative.masses, the (local) strength of the potential well representing the parent galaxy, and the number of cores. We have studied the dependence of the merger rates and the nature of the final merger product on these parameters. Individual cores survive much longer in stronger background potentials. Cores can survive for a substantial fraction of a Hubble time if they travel on reasonable orbits.

  10. Kinematic GPS solutions for aircraft trajectories: Identifying and minimizing systematic height errors associated with atmospheric propagation delays

    USGS Publications Warehouse

    Shan, S.; Bevis, M.; Kendrick, E.; Mader, G.L.; Raleigh, D.; Hudnut, K.; Sartori, M.; Phillips, D.

    2007-01-01

    When kinematic GPS processing software is used to estimate the trajectory of an aircraft, unless the delays imposed on the GPS signals by the atmosphere are either estimated or calibrated via external observations, then vertical height errors of decimeters can occur. This problem is clearly manifested when the aircraft is positioned against multiple base stations in areas of pronounced topography because the aircraft height solutions obtained using different base stations will tend to be mutually offset, or biased, in proportion to the elevation differences between the base stations. When performing kinematic surveys in areas with significant topography it should be standard procedure to use multiple base stations, and to separate them vertically to the maximum extent possible, since it will then be much easier to detect mis-modeling of the atmosphere. Copyright 2007 by the American Geophysical Union.

  11. Wing kinematics in a hovering dronefly minimize power expenditure.

    PubMed

    Wu, J H; Sun, M

    2014-10-15

    When an insect hovers or performs constant-speed flight, its wings flap at certain amplitude, frequency, angle of attack, etc., and the flight is balanced (vertical force equals to the weight, and horizontal force and pitch moment are zero). It is possible that when some other sets of values of wing kinematical parameters are used, the force and moment balance conditions can still be satisfied. Does the wing kinematics used by a constant-speed flying insect minimize the power expenditure? In this study, whether the wing kinematics used by a freely hovering dronefly minimizes its energy expenditure was investigated. First, the power consumption using the set of values of wing kinematical parameters that was actually employed by the insect was computed. Then, the kinematical parameters were changed while keeping the equilibrium flight conditions satisfied, and the power consumption was recalculated. It was found that wing kinematical parameters used by the freely hovering dronefly are very close to that minimize its energy consumption, and they can ensure the margin of controllability from hovering to maneuvers. That is, slight change of wing kinematical parameters did not cause significant change of the specific power (maintained a relatively small value).

  12. Motor control of voluntary arm movements. Kinematic and modelling study.

    PubMed

    Corradini, M L; Gentilucci, M; Leo, T; Rizzolatti, G

    1992-01-01

    The motor control of pointing and reaching-to-grasp movements was investigated using two different approaches (kinematic and modelling) in order to establish whether the type of control varies according to modifications of arm kinematics. Kinematic analysis of arm movements was performed on subjects' hand trajectories directed to large and small stimuli located at two different distances. The subjects were required either to grasp and to point to each stimulus. The kinematics of the subsequent movement, during which subject's hand came back to the starting position, were also studied. For both movements, kinematic analysis was performed on hand linear trajectories as well as on joint angular trajectories of shoulder and elbow. The second approach consisted in the parametric identification of the black box (ARMAX) model of the controller driving the arm movement. Such controller is hypothesized to work for the correct execution of the motor act. The order of the controller ARMAX model was analyzed with respect to the different experimental conditions (distal task, stimulus size and distance). Results from kinematic analysis showed that target distance and size influenced kinematic parameters both of angular and linear displacements. Nevertheless, the structure of the motor program was found to remain constant with distance and distal task, while it varied with precision requirements due to stimulus size. The estimated model order of the controller confirmed the invariance of the control law with regard to movement amplitude, whereas it was sensitive to target size.

  13. From nearby to distant galaxies: kinematical and dynamical studies

    NASA Astrophysics Data System (ADS)

    Epinat, Benoit

    2009-09-01

    Kinematical studies of low and high redshift galaxies enables to probe galaxy formation and evolution scenarios. Integral field spectroscopy is a powerful tool to study with accuracy nearby galaxies kinematics. Recent observations also gives a new 2D vision of high redshift galaxies kinematics. This work mostly relies on the kinematical sample of galaxies GHASP. This control sample, composed of 203 local spiral and irregular galaxies in low density environments observed with Fabry-Perot techniques in the Ha line (6563 A), is by now the largest sample of Fabry-Perot data. After a revue on Fabry-Perot interferometry and a presentation of new data reduction procedures, my implications on both 3D-NTT Fabry-Perot instrument and the wide field spectrograph project (WFSpec) for galaxy evolution study with the european ELT are developed. The second section is dedicated to GHASP data. This sample have been fully reduced and analysed using new methods. The kinematical analysis of 2D kinematical maps has been undertaken with the study of the dark matter distribution, the rotation curves shape, bar signatures and the ionized gas velocity dispersion. In a third section, this local reference sample is used as a zero point for high redshift galaxies kinematical studies. The GHASP sample is projected at high redshift (z=1.7) in order to disentangle evolution effects from distance biases in high redshift galaxies kinematical data observed with SINFONI, OSIRIS and GIRAFFE. The kinematical analysis of new SINFONI high redshift observations is also presented and high redshift data found in the literature are compared with GHASP projected sample, suggesting some evolution of the galaxy dynamical support within the ages.

  14. Beyond the Kuiper Belt Edge

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott

    2012-06-01

    Of the thousands of known objects beyond Neptune, only one has a perihelion significantly beyond 50 AU, Sedna at 75 AU. Kuiper Belt surveys to date have not been optimized to survey beyond the Kuiper Belt edge at 50 AU. Most of these surveys either did not go faint enough, did not have the required long cadence to detect very slow moving objects or covered too small of an area of sky. The dynamical and physical properties of objects in this region offer key constraints on the formation and evolution of our solar system. In order to probe the Sedna like population of objects with moderate radii (100 km) we propose a deep wide-field outer solar system survey. This survey will allow us to determine if the objects beyond 50 AU are fainter than expected, if there is truly a dearth of objects, or if the Kuiper Belt continues again after some sizable gap possibly caused by a planet sized object. We will be able to examine the origin of Sedna and determine if this eccentric, distant body is unique (as once believed for Pluto) or just the first of a new class of object in the outer Solar System. We will also explore the Neptune Trojans and scattered disk populations through the survey.

  15. Beyond the Kuiper Belt Edge

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott

    2011-01-01

    Of the thousands of known objects beyond Neptune, only one has a perihelion significantly beyond 50 AU, Sedna at 75 AU. Kuiper Belt surveys to date have not been optimized to survey beyond the Kuiper Belt edge at 50 AU. Most of these surveys either did not go faint enough, did not have the required long cadence to detect very slow moving objects or covered too small of an area of sky. The dynamical and physical properties of objects in this region offer key constraints on the formation and evolution of our solar system. In order to probe the Sedna like population of objects with moderate radii (100 km) we propose a deep wide-field outer solar system survey. This survey will allow us to determine if the objects beyond 50 AU are fainter than expected, if there is truly a dearth of objects, or if the Kuiper Belt continues again after some sizable gap possibly caused by a planet sized object. We will be able to examine the origin of Sedna and determine if this eccentric, distant body is unique (as once believed for Pluto) or just the first of a new class of object in the outer Solar System. We will also explore the Neptune Trojans and scattered disk populations through the survey.

  16. Beyond the Kuiper Belt Edge

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott; Trujillo, Chad

    2012-02-01

    Of the thousands of known objects beyond Neptune, only one has a perihelion significantly beyond 50 AU, Sedna at 75 AU. Kuiper Belt surveys to date have not been optimized to survey beyond the Kuiper Belt edge at 50 AU. Most of these surveys either did not go faint enough, did not have the required long cadence to detect very slow moving objects or covered too small of an area of sky. The dynamical and physical properties of objects in this region offer key constraints on the formation and evolution of our solar system. In order to probe the Sedna like population of objects with moderate radii (100 km) we propose a medium wide-field outer solar system survey. This survey will allow us to determine if the objects beyond 50 AU are fainter than expected, if there is truly a dearth of objects, or if the Kuiper Belt continues again after some sizable gap possibly caused by a planet sized object. We will be able to examine the origin of Sedna and determine if this eccentric, distant body is unique (as once believed for Pluto) or just the first of a new class of object in the outer Solar System.

  17. Gyrokinetic Models for Edge Plasmas*

    NASA Astrophysics Data System (ADS)

    Dimits, Andris

    2010-11-01

    The use of gyrokinetic equations for the simulation of magnetic fusion edge and scrapeoff-layer plasmas requires that the equations be valid for large relative perturbation amplitudes and, possibly, large flows. The Hamiltonian gyrokinetic theory has therefore been extended to two new orderings [1,2] that are more general than the standard ones in that they allow for potential perturbations or ExB flows of order the thermal levels. These theories both generalize and show that additional terms should have been present some related prior work. Here, full (low-β) electromagnetic toroidal equation sets are presented, and he energy conservation relations are derived using Noether's theorem in a Lagrangian variational approach. Useful subsidiary and reduced orderings are also considered that result in considerable simplification, and methods for the numerical implementation of the new terms in the equations will also be discussed. *This work was performed for US DOE by LLNL under Contract DE-AC52-07NA27344 and is part of the ESL. [4pt] [1] A.M. Dimits et al., Phys. Fluids B4, 274 (1992). [0pt] [2] A.M. Dimits, Phys. Plasmas 17, 055901 (2010).

  18. Comparing object recognition from binary and bipolar edge features

    PubMed Central

    Jung, Jae-Hyun; Pu, Tian; Peli, Eli

    2017-01-01

    Edges derived from abrupt luminance changes in images carry essential information for object recognition. Typical binary edge images (black edges on white background or white edges on black background) have been used to represent features (edges and cusps) in scenes. However, the polarity of cusps and edges may contain important depth information (depth from shading) which is lost in the binary edge representation. This depth information may be restored, to some degree, using bipolar edges. We compared recognition rates of 16 binary edge images, or bipolar features, by 26 subjects. Object recognition rates were higher with bipolar edges and the improvement was significant in scenes with complex backgrounds.

  19. Computational neural learning formalisms for manipulator inverse kinematics

    NASA Technical Reports Server (NTRS)

    Gulati, Sandeep; Barhen, Jacob; Iyengar, S. Sitharama

    1989-01-01

    An efficient, adaptive neural learning paradigm for addressing the inverse kinematics of redundant manipulators is presented. The proposed methodology exploits the infinite local stability of terminal attractors - a new class of mathematical constructs which provide unique information processing capabilities to artificial neural systems. For robotic applications, synaptic elements of such networks can rapidly acquire the kinematic invariances embedded within the presented samples. Subsequently, joint-space configurations, required to follow arbitrary end-effector trajectories, can readily be computed. In a significant departure from prior neuromorphic learning algorithms, this methodology provides mechanisms for incorporating an in-training skew to handle kinematics and environmental constraints.

  20. Fault tolerant kinematic control of hyper-redundant manipulators

    NASA Technical Reports Server (NTRS)

    Bedrossian, Nazareth S.

    1994-01-01

    Hyper-redundant spatial manipulators possess fault-tolerant features because of their redundant structure. The kinematic control of these manipulators is investigated with special emphasis on fault-tolerant control. The manipulator tasks are viewed in the end-effector space while actuator commands are in joint-space, requiring an inverse kinematic algorithm to generate joint-angle commands from the end-effector ones. The rate-inverse kinematic control algorithm presented in this paper utilizes the pseudoinverse to accommodate for joint motor failures. An optimal scale factor for the robust inverse is derived.

  1. Internal Kinematics of Distant Field Galaxies

    NASA Astrophysics Data System (ADS)

    Ing, Kristine Mei Lan

    1998-08-01

    We study faint blue field galaxies in two complementary ways by targeting red-shifted, broadened emission lines: (1) a detailed study of a small but representative sample using resolved images that reveal the internal kinematics of individual galaxies, and analyzing effects like ionized gas distribution and galaxy inclination that tend to bias the results obtained from spatially unresolved galaxy spectra; and (2) a study of a spatially unresolved but statistically complete sample within our color, magnitude, and redshift cuts. In order to facilitate comparison of distant and local galaxies, we have developed a methodology to study distant galaxies in as much detail as is customary for nearby galaxies, using state-of-the-art data. The ultimate goal of such a comparison is to determine the amount of evolution of the mass-to-light ratio of individual galaxies and to thereby constrain models of galaxy formation and evolution. In a followup to our recent multifiber spectroscopic study of the linewidth-vs-luminosity relation in faint blue galaxies at < z>~ 0.25 (Rix et al. 1997, MNRAS, 285, 779), we have carried out a detailed study of the internal kinematics of 10 distant (z = 0.30[-]0.44), faint (B = 20[-]24), blue (B-R <= 1.2) field galaxies using the Rutgers Fabry-Perot (RFP) instrument on the Cerro Tololo Interamerican Observatory's 4-meter telescope. In deriving rotation speeds from fiber spectra, we had to rely on large and somewhat uncertain statistical corrections for the effects of non-uniform gas distribution, disk inclination, shape of the rotation curve, and seeing. Using fitting disk models to the RFP datacube, complemented by surface photometry and isophotal shapes derived from high angular resolution Hubble Space Telescope Wide Field/Planetary Camera-2 images in the F814W ('I') or F555W ('V') Band and deep H-Band (1.6 μm) images obtained with the Near InfraRed Camera on the Keck 10-meter telescope, the RFP study addresses these issues directly and yields

  2. Quantum gravity kinematics from extended TQFTs

    NASA Astrophysics Data System (ADS)

    Dittrich, Bianca; Geiller, Marc

    2017-01-01

    In this paper, we show how extended topological quantum field theories (TQFTs) can be used to obtain a kinematical setup for quantum gravity, i.e. a kinematical Hilbert space together with a representation of the observable algebra including operators of quantum geometry. In particular, we consider the holonomy-flux algebra of (2 + 1)-dimensional Euclidean loop quantum gravity, and construct a new representation of this algebra that incorporates a positive cosmological constant. The vacuum state underlying our representation is defined by the Turaev-Viro TQFT. This vacuum state can be thought of as being peaked on connections with homogeneous curvature. We therefore construct here a generalization, or more precisely a quantum deformation at root of unity, of the previously introduced SU(2) BF representation. The extended Turaev-Viro TQFT provides a description of the excitations on top of the vacuum. These curvature and torsion excitations are classified by the Drinfeld center category of the quantum deformation of SU(2), and are essential in order to allow for a representation of the holonomies and fluxes. The holonomies and fluxes are generalized to ribbon operators which create and interact with the excitations. These excitations agree with the ones induced by massive and spinning particles, and therefore the framework presented here allows automatically for a description of the coupling of such matter to (2+1)-dimensional gravity with a cosmological constant. The new representation constructed here presents a number of advantages over the representations which exist so far. In particular, it possesses a very useful finiteness property which guarantees the discreteness of spectra for a wide class of quantum (intrinsic and extrinsic) geometrical operators. Also, the notion of basic excitations leads to a so-called fusion basis which offers exciting possibilities for the construction of states with interesting global properties, as well as states with certain

  3. Line profiles from discrete kinematic data

    NASA Astrophysics Data System (ADS)

    Amorisco, N. C.; Evans, N. W.

    2012-08-01

    We develop a method to extract the shape information of line profiles from discrete kinematic data. The Gauss-Hermite expansion, which is widely used to describe the line-of-sight velocity distributions extracted from absorption spectra of elliptical galaxies, is not readily applicable to samples of discrete stellar velocity measurements, accompanied by individual measurement errors and probabilities of membership. These include data sets on the kinematics of globular clusters and planetary nebulae in the outer parts of elliptical galaxies, as well as giant stars in the Local Group galaxies and the stellar populations of the Milky Way. We introduce two-parameter families of probability distributions describing symmetric and asymmetric distortions of the line profiles from Gaussianity. These are used as the basis of a maximum likelihood estimator to quantify the shape of the line profiles. Tests show that the method outperforms a Gauss-Hermite expansion for discrete data, with a lower limit for the relative gain of ≈2 for sample sizes N ≈ 800. To ensure that our methods can give reliable descriptions of the shape, we develop an efficient test to assess the statistical quality of the obtained fit. As an application, we turn our attention to the discrete velocity data sets of the dwarf spheroidals (dSphs) of the Milky Way. Sculptor and Fornax have data sets of ≳1000 line-of-sight velocities of probable member stars. In Sculptor, the symmetric deviations are everywhere consistent with velocity distributions more peaked than Gaussian. In Fornax, instead, there is an evolution in the symmetric deviations of the line profile from a peakier to more flat-topped distribution on moving outwards. Although the data sets for Carina and Sextans are smaller, they still comprise several hundreds of stars. Our methods are sensitive enough to detect evidence for velocity distributions more peaked than Gaussian. These results suggest a radially biased orbital structure for the

  4. Kinematical and Dynamical Modeling of Elliptical Galaxies

    NASA Astrophysics Data System (ADS)

    Mamon, G. A.; Łokas, E.; Dekel, A.; Stoehr, F.; Cox, T. J.

    Elements of kinematical and dynamical modeling of elliptical galaxies are presented. In projection, NFW models resemble Sérsic models, but with a very narrow range of shapes (m=3±1). The total density profile of ellipticals cannot be NFW-like because the predicted local M/L and aperture velocity dispersion within an effective radius (R_e) are much lower than observed. Stars must then dominate ellipticals out to a few R_e. Fitting an NFW model to the total density profile of Sérsic+NFW (stars+dark matter [DM]) ellipticals results in very high concentration parameters, as found by X-ray observers. Kinematical modeling of ellipticals assuming an isotropic NFW DM model underestimates M/L at the virial radius by a factor of 1.6 to 2.4, because dissipationless ΛCDM halos have slightly different density profiles and slightly radial velocity anisotropy. In N-body+gas simulations of ellipticals as merger remnants of spirals embedded in DM halos, the slope of the DM density profile is steeper when the initial spiral galaxies are gas-rich. The Hansen & Moore (2006) relation between anisotropy and the slope of the density profile breaks down for gas and DM, but the stars follow an analogous relation with slightly less radial anisotropies for a given density slope. Using kurtosis (h_4) to infer anisotropy in ellipticals is dangerous, as h4 is also sensitive to small levels of rotation. The stationary Jeans equation provides accurate masses out to 8 R_e. The discrepancy between the modeling of Romanowsky et al. (2003), indicating a dearth of DM in ellipticals, and the simulations analyzed by Dekel et al. (2005), which match the spectroscopic observations of ellipticals, is partly due to radial anisotropy and to observing oblate ellipticals face-on. However, one of the 15 solutions to the orbit modeling of Romanowsky et al. is found to have an amount and concentration of DM consistent with ΛCDM predictions.

  5. Eliminating Unbonded Edges In Explosive Bonding

    NASA Technical Reports Server (NTRS)

    Bement, Laurence J.; Kushnick, Anne C.

    1991-01-01

    Explosive-bonding technique elminates sharp unbonded notch normally occurring between flyer plate and baseplate. Makes it possible to simply break away unbonded outer extremity of flyer plate; no longer necessary to grind away unbonded edge to prevent collection of corrosive contaminants in edge voids. Method not limited to flat surfaces.

  6. How Forest Inhomogeneities Affect the Edge Flow

    NASA Astrophysics Data System (ADS)

    Boudreault, Louis-Étienne; Dupont, Sylvain; Bechmann, Andreas; Dellwik, Ebba

    2017-03-01

    Most of our knowledge on forest-edge flows comes from numerical and wind-tunnel experiments where canopies are horizontally homogeneous. To investigate the impact of tree-scale heterogeneities ({>}1 m) on the edge-flow dynamics, the flow in an inhomogeneous forest edge on Falster island in Denmark is investigated using large-eddy simulation. The three-dimensional forest structure is prescribed in the model using high resolution helicopter-based lidar scans. After evaluating the simulation against wind measurements upwind and downwind of the forest leading edge, the flow dynamics are compared between the scanned forest and an equivalent homogeneous forest. The simulations reveal that forest inhomogeneities facilitate flow penetration into the canopy from the edge, inducing important dispersive fluxes in the edge region as a consequence of the flow spatial variability. Further downstream from the edge, the forest inhomogeneities accentuate the canopy-top turbulence and the skewness of the wind-velocity components while the momentum flux remains unchanged. This leads to a lower efficiency in the turbulent transport of momentum within the canopy. Dispersive fluxes are only significant in the upper canopy. Above the canopy, the mean flow is less affected by the forest inhomogeneities. The inhomogeneities induce an increase in the mean wind speed that was found to be equivalent to a decrease in the aerodynamic height of the canopy. Overall, these results highlight the importance of forest inhomogeneities when looking at canopy-atmosphere exchanges in forest-edge regions.

  7. Annotated Bibliography of EDGE2D Use

    SciTech Connect

    J.D. Strachan and G. Corrigan

    2005-06-24

    This annotated bibliography is intended to help EDGE2D users, and particularly new users, find existing published literature that has used EDGE2D. Our idea is that a person can find existing studies which may relate to his intended use, as well as gain ideas about other possible applications by scanning the attached tables.

  8. How Forest Inhomogeneities Affect the Edge Flow

    NASA Astrophysics Data System (ADS)

    Boudreault, Louis-Étienne; Dupont, Sylvain; Bechmann, Andreas; Dellwik, Ebba

    2016-09-01

    Most of our knowledge on forest-edge flows comes from numerical and wind-tunnel experiments where canopies are horizontally homogeneous. To investigate the impact of tree-scale heterogeneities ({>}1 m) on the edge-flow dynamics, the flow in an inhomogeneous forest edge on Falster island in Denmark is investigated using large-eddy simulation. The three-dimensional forest structure is prescribed in the model using high resolution helicopter-based lidar scans. After evaluating the simulation against wind measurements upwind and downwind of the forest leading edge, the flow dynamics are compared between the scanned forest and an equivalent homogeneous forest. The simulations reveal that forest inhomogeneities facilitate flow penetration into the canopy from the edge, inducing important dispersive fluxes in the edge region as a consequence of the flow spatial variability. Further downstream from the edge, the forest inhomogeneities accentuate the canopy-top turbulence and the skewness of the wind-velocity components while the momentum flux remains unchanged. This leads to a lower efficiency in the turbulent transport of momentum within the canopy. Dispersive fluxes are only significant in the upper canopy. Above the canopy, the mean flow is less affected by the forest inhomogeneities. The inhomogeneities induce an increase in the mean wind speed that was found to be equivalent to a decrease in the aerodynamic height of the canopy. Overall, these results highlight the importance of forest inhomogeneities when looking at canopy-atmosphere exchanges in forest-edge regions.

  9. Deformable wing kinematics in the desert locust: how and why do camber, twist and topography vary through the stroke?

    PubMed Central

    Walker, Simon M.; Thomas, Adrian L. R.; Taylor, Graham K.

    2009-01-01

    Here, we present a detailed analysis of the wing kinematics and wing deformations of desert locusts (Schistocerca gregaria, Forskål) flying tethered in a wind tunnel. We filmed them using four high-speed digital video cameras, and used photogrammetry to reconstruct the motion of more than 100 identified points. Whereas the hindwing motions were highly stereotyped, the forewing motions showed considerable variation, consistent with a role in flight control. Both wings were positively cambered on the downstroke. The hindwing was cambered through an ‘umbrella effect’ whereby the trailing edge tension compressed the radial veins during the downstroke. Hindwing camber was reversed on the upstroke as the wing fan corrugated, reducing the projected area by 30 per cent, and releasing the tension in the trailing edge. Both the wings were strongly twisted from the root to the tip. The linear decrease in incidence along the hindwing on the downstroke precisely counteracts the linear increase in the angle of attack that would otherwise occur in root flapping for an untwisted wing. The consequent near-constant angle of attack is reminiscent of the optimum for a propeller of constant aerofoil section, wherein a linear twist distribution allows each section to operate at the unique angle of attack maximizing the lift to drag ratio. This implies tuning of the structural, morphological and kinematic parameters of the hindwing for efficient aerodynamic force production. PMID:19091683

  10. [Gap edge effect of Castanopsis kawakamii community].

    PubMed

    Liu, Jinfu; Hong, Wei; Li, Junqing; Lin, Rongfu

    2003-09-01

    This paper reported the characters of gap edge effect of Castanopsis kawakamii community in Sanming, Fujian Province. The species diversity, ecological dominance, and edge effect strength of 38 forest gaps with different development stages in different stands of Castanopsis kawakamii community were measured, and Shannon-Wiener index, Simpson index, and index of edge effect strength were calculated. The results showed that the index of the gap edge effect of Castanopsis kawakamii community was about 0.7-1.3 (according to the species diversity index) and 0.3-1.8 (according to the ecological dominance index). The gap edge effect had the trend of increasing the species diversity of forest communities. The index of gap effect was affected by the size and development stage of the gap and the related forest type. The study provided a theoretical basis for the maintenance of species diversity and the forest management in Castanopsis kawakamii community.

  11. Edge plasmons in monolayer black phosphorus

    NASA Astrophysics Data System (ADS)

    Bao, Zhi-Wei; Wu, Hong-Wei; Zhou, Yu

    2016-12-01

    In this paper, we numerically investigate the edge plasmons in monolayer black phosphorus. It is found that the complex effective indexes of these modes depend on the molecular configuration of the edge. We have calculated the ratio of the real over the imaginary part of the mode effective index, and the results indicate that such edge modes indeed possess outstanding propagation performances in the mid-infrared. In the case of black phosphorus nanoribbon, it seems that only the anti-symmetric modes have low losses, and may be of use in applications. Compared with those at the edge of monolayer black phosphorus, the propagation performances can be further enhanced due to the mode coupling between the two edges. In the end, the effects of substrates are discussed. Our study shows that monolayer black phosphorus may be regarded as a promising candidate for plasmonic applications in the mid-infrared.

  12. Sensitivity Analysis of Automated Ice Edge Detection

    NASA Astrophysics Data System (ADS)

    Moen, Mari-Ann N.; Isaksem, Hugo; Debien, Annekatrien

    2016-08-01

    The importance of highly detailed and time sensitive ice charts has increased with the increasing interest in the Arctic for oil and gas, tourism, and shipping. Manual ice charts are prepared by national ice services of several Arctic countries. Methods are also being developed to automate this task. Kongsberg Satellite Services uses a method that detects ice edges within 15 minutes after image acquisition. This paper describes a sensitivity analysis of the ice edge, assessing to which ice concentration class from the manual ice charts it can be compared to. The ice edge is derived using the Ice Tracking from SAR Images (ITSARI) algorithm. RADARSAT-2 images of February 2011 are used, both for the manual ice charts and the automatic ice edges. The results show that the KSAT ice edge lies within ice concentration classes with very low ice concentration or open water.

  13. Edge effects on water droplet condensation

    NASA Astrophysics Data System (ADS)

    Medici, Marie-Gabrielle; Mongruel, Anne; Royon, Laurent; Beysens, Daniel

    2014-12-01

    In this study we investigate the effect of geometrical or thermal discontinuities on the growth of water droplets condensing on a cooled substrate. Edges, corners, and cooled and noncooled boundaries can have a strong effect on the vapor concentration profile and mass diffusion around the drops. In comparison to growth in a pattern where droplets have to compete to catch vapor, which results in a linear water concentration profile directed perpendicularly to the substrate, droplets near discontinuities can get more vapor (outer edges, corners), resulting in faster growth or less vapor (inner edges), giving lower growth. When the cooling heat flux limits growth instead of mass diffusion (substrate with low thermal conductivity, strong heat exchange with air), edge effects can be canceled. In certain cases, growth enhancement can reach nearly 500% on edges or corners.

  14. Living on the edge: roads and edge effects on small mammal populations.

    PubMed

    Fuentes-Montemayor, Elisa; Cuarón, Alfredo D; Vázquez-Domínguez, Ella; Benítez-Malvido, Julieta; Valenzuela-Galván, David; Andresen, Ellen

    2009-07-01

    1. Roads may affect wildlife populations through habitat loss and disturbances, as they create an abrupt linear edge, increasing the proportion of edge exposed to a different habitat. Three types of edge effects have been recognized: abiotic, direct biotic, and indirect biotic. 2. We explored the direct biotic edge effects of 3- to 4-m wide roads, and also a previously unrecognized type of edge effect: social. We live-trapped two threatened endemic rodents from Cozumel Island (Oryzomys couesi cozumelae and Reithrodontomys spectabilis) in 16 plots delimited by roads on two sides, to compare edge effects between two adjacent edges (corners), single-edge and interior forest, on life history and social variables. 3. No significant edge effects were observed on the life-history variables, with the exception of differences in body condition between males and females of O. c. cozumelae near edges. Both species showed significant and contrasting effects on their social variables. 4. O. c. cozumelae was distributed according to its age and sex: the proportion of adults and males was higher in interior than near edges, while juveniles and females were more abundant near edges. More nonreproductive females were present in corners than in single-edge and interior, while the opposite distribution was observed for nonreproductive males. 5. The distribution of R. spectabilis was related to its age and reproductive condition, but not to its sex. The proportion of adults was significantly higher in corners, while juveniles were only caught in single-edge and interior quadrants. The proportion of reproductive individuals was higher in edge than interior quadrants, while reproductive females were only present in edge quadrants. 6. We found significant differences between the quadrants with the greatest edge exposure in comparison with other quadrants. The social edge effects we identified complement the typology of edge effects recognized in ecological literature. Our study provides

  15. THE STELLAR AND GAS KINEMATICS OF THE LITTLE THINGS DWARF IRREGULAR GALAXY NGC 1569

    SciTech Connect

    Johnson, Megan; Hunter, Deidre A.; Zhang, Hong-Xin; Herrmann, Kimberly; Oh, Se-Heon; Elmegreen, Bruce; Brinks, Elias; Tollerud, Erik E-mail: dah@lowell.edu E-mail: herrmann@lowell.edu E-mail: bge@us.ibm.com E-mail: etolleru@uci.edu

    2012-11-01

    In order to understand the formation and evolution of Magellanic-type dwarf irregular (dIm) galaxies, one needs to understand their three-dimensional structure. We present measurements of the stellar velocity dispersion in NGC 1569, a nearby post-starburst dIm galaxy. The stellar vertical velocity dispersion, {sigma}{sub z}, coupled with the maximum rotational velocity derived from H I observations, V{sub max}, gives a measure of how kinematically hot the galaxy is, and, therefore, indicates its structure. We conclude that the stars in NGC 1569 are in a thick disk with a V{sub max}/{sigma}{sub z} = 2.4 {+-} 0.7. In addition to the structure, we analyze the ionized gas kinematics from O III observations along the morphological major axis. These data show evidence for outflow from the inner starburst region and a potential expanding shell near supermassive star cluster (SSC) A. When compared to the stellar kinematics, the velocity dispersion of the stars increases in the region of SSC A supporting the hypothesis of an expanding shell. The stellar kinematics closely follow the motion of the gas. Analysis of high-resolution H I data clearly reveals the presence of an H I cloud that appears to be impacting the eastern edge of NGC 1569. Also, an ultra-dense H I cloud can be seen extending to the west of the impacting H I cloud. This dense cloud is likely the remains of a dense H I bridge that extended through what is now the central starburst area. The impacting H I cloud was the catalyst for the starburst, thus turning the dense gas into stars over a short timescale, {approx}1 Gyr. We performed a careful study of the spectral energy distribution using infrared, optical, and ultraviolet photometry, producing a state-of-the-art mass model for the stellar disk. This mass modeling shows that stars dominate the gravitational potential in the inner 1 kpc. The dynamical mass of NGC 1569, derived from V{sub max}, shows that the disk may be dark matter deficient in the inner

  16. The Stellar and Gas Kinematics of the LITTLE THINGS Dwarf Irregular Galaxy NGC 1569

    NASA Astrophysics Data System (ADS)

    Johnson, Megan; Hunter, Deidre A.; Oh, Se-Heon; Zhang, Hong-Xin; Elmegreen, Bruce; Brinks, Elias; Tollerud, Erik; Herrmann, Kimberly

    2012-11-01

    In order to understand the formation and evolution of Magellanic-type dwarf irregular (dIm) galaxies, one needs to understand their three-dimensional structure. We present measurements of the stellar velocity dispersion in NGC 1569, a nearby post-starburst dIm galaxy. The stellar vertical velocity dispersion, σz, coupled with the maximum rotational velocity derived from H I observations, V max, gives a measure of how kinematically hot the galaxy is, and, therefore, indicates its structure. We conclude that the stars in NGC 1569 are in a thick disk with a V max/σz = 2.4 ± 0.7. In addition to the structure, we analyze the ionized gas kinematics from O III observations along the morphological major axis. These data show evidence for outflow from the inner starburst region and a potential expanding shell near supermassive star cluster (SSC) A. When compared to the stellar kinematics, the velocity dispersion of the stars increases in the region of SSC A supporting the hypothesis of an expanding shell. The stellar kinematics closely follow the motion of the gas. Analysis of high-resolution H I data clearly reveals the presence of an H I cloud that appears to be impacting the eastern edge of NGC 1569. Also, an ultra-dense H I cloud can be seen extending to the west of the impacting H I cloud. This dense cloud is likely the remains of a dense H I bridge that extended through what is now the central starburst area. The impacting H I cloud was the catalyst for the starburst, thus turning the dense gas into stars over a short timescale, ~1 Gyr. We performed a careful study of the spectral energy distribution using infrared, optical, and ultraviolet photometry, producing a state-of-the-art mass model for the stellar disk. This mass modeling shows that stars dominate the gravitational potential in the inner 1 kpc. The dynamical mass of NGC 1569, derived from V max, shows that the disk may be dark matter deficient in the inner region, although, when compared to the expected

  17. Large Lewis No. Edge-Flame Instabilities

    NASA Technical Reports Server (NTRS)

    Buckmaster, J.

    2001-01-01

    Edge-flames play an important role in a number of microgravity investigations, and in the general study of flames. Examples include the candle-flame experiments carried out on board both the Space Shuttle and the Mir Space Station; the flame-spread-over-liquid work carried out by H. Ross and W. Sirignano amongst others and lifted turbulent diffusion flames. In all of these configurations a local two-dimensional flame structure can be identified which looks like a flame-sheet with an edge, and these structures exhibit dynamical behavior which characterizes them and distinguishes them from ad hoc 2D flame structures. Edge-flames can exist in both a non-premixed context (edges of diffusion flames) and in a premixed context (edges of deflagrations), but the work reported here deals with the edges of diffusion flames. It is particularly relevant, we believe, to oscillations that have been seen in both the candle-flame context, and the flame-spread-over-liquid context. These oscillations are periodic edge-oscillations (in an appropriate reference frame), sans oscillation of the trailing diffusion flame. It is shown that if the Lewis number of the fuel is sufficiently large (the Lewis number of the oxidizer is taken to be 1), and the Damkohler number is sufficiently small, oscillating-edge solutions can be found. Oscillations are encouraged by an on-edge convective flow and the insertion of a cold probe, discouraged by an off-edge convective flow. In the present work, the nature of these oscillations is examined in more depth, using a variety of numerical strategies.

  18. Scapulothoracic kinematics during tennis forehand drive.

    PubMed

    Rogowski, Isabelle; Creveaux, Thomas; Chèze, Laurence; Dumas, Raphaël

    2014-06-01

    Scapular dyskinesis is recognized as an abnormality in the kinetic chain; yet, there has been little research quantifying scapular motion during sport tasks. Tennis forehand drives of eight highly skilled tennis players were studied to assess the scapulothoracic kinematics and evaluate repeatability using video-based motion analysis. Scapulothoracic downward/upward rotation, posterior/anterior tilt, and internal/external rotation were computed using an acromial marker cluster. On average, the upward rotation, anterior tilt, and internal rotation varied from 1 degrees to 26 degrees, from 7 degrees to 32 degrees, and from 42 degrees to 100 degrees, respectively, during the tennis forehand drive. During the backswing and forward swing phases of the forehand stroke, small changes were observed for the three scapular angle values, while all angles increased rapidly during the follow-through phase. This suggests that the tennis forehand drive may contribute to scapula dyskinesis, mainly due to the great amplitude in scapulothoracic anterior tilt and internal rotation observed during the follow-through phase. Knowledge of normal scapula motion during sport tasks performed at high velocity could improve the understanding of various sport-specific adaptations and pathologies.

  19. The [N II] Kinematics of R Aquarii

    NASA Technical Reports Server (NTRS)

    Hollis, J. M.; Vogel, S. N.; VanBuren, D.; Strong, J. P.; Lyon, R. G.; Dorband, J. E.

    1998-01-01

    We report a kinematic study of the symbiotic star system R Aqr derived from [N H]lambda 6584 emission observations with a Fabry-Perot imaging spectrometer. The [N II] spatial structure of the R Aqr jet, first observed circa 1977, and surrounding hourglass-shaped nebulosity, due to an explosion approximately 660 years ago, are derived from 41 velocity planes spaced at approximately 12 km/s intervals. Fabry-Perot imagery shows the elliptical nebulosity comprising the waist of the hourglass shell is consistent with a circular ring expanding radially at 55 km/s as seen at an inclination angle, i approximately 70 deg. Fabry-Perot imagery shows the two-sided R Aqr jet is collimated flow in opposite directions. The intensity-velocity structure of the strong NE jet component is shown in contrast to the amorphous SW jet component. We offer a idealized schematic model for the R Aqr jet motion which results in a small-scale helical structure forming around a larger-scale helical path. The implications of such a jet model are discussed. We present a movie showing a side-by-side comparison of the spatial structure of the model and the data as a function of the 41 velocity planes.

  20. Kinematical properties of coronal mass ejections

    NASA Astrophysics Data System (ADS)

    Temmer, M.

    2016-11-01

    Coronal mass ejections (CMEs) are the most dynamic phenomena in our solar system. They abruptly disrupt the continuous outflow of solar wind by expelling huge clouds of magnetized plasma into interplanetary space with velocities enabling to cross the Sun-Earth distance within a few days. Earth-directed CMEs may cause severe geomagnetic storms when their embedded magnetic fields and the shocks ahead compress and reconnect with the Earth's magnetic field. The transit times and impacts in detail depend on the initial CME velocity, size, and mass, as well as on the conditions and coupling processes with the ambient solar wind flow in interplanetary space. The observed CME parameters may be severely affected by projection effects and the constant changing environmental conditions are hard to derive. This makes it difficult to fully understand the physics behind CME evolution, preventing to do a reliable forecast of Earth-directed events. This short review focusing on observational data, shows recent methods which were developed to derive the CME kinematical profile for the entire Sun-Earth distance range as well as studies which were performed to shed light on the physical processes that CMEs encounter when propagating from Sun to Earth.

  1. Tibiocalcaneal kinematics of barefoot versus shod running.

    PubMed

    Stacoff, A; Nigg, B M; Reinschmidt, C; van den Bogert, A J; Lundberg, A

    2000-11-01

    Barefoot running kinematics has been described to vary considerably from shod running. However, previous investigations were typically based on externally mounted shoe and/or skin markers, which have been shown to overestimate skeletal movements. Thus, the purpose of this study was to compare calcaneal and tibial movements of barefoot versus shod running using skeletal markers. Intracortical bone pins with reflective marker triads were inserted under standard local anesthetic into the calcaneus and tibia of five healthy male subjects. The subjects ran barefoot, with a normal shoe, with three shoe soles and two orthotic modifications. The three-dimensional tibiocalcaneal rotations were determined using a joint coordinate system approach. Test variables were defined for eversion and tibial rotation. The results showed that the differences in bone movements between barefoot and shod running were small and unsystematic (mean effects being less than 2 degrees ) compared with the differences between the subjects (up to 10 degrees ). However, differences may occur during midstance when extreme shoe modifications (i.e. posterior orthosis) are used. It is concluded that calcaneal and tibial movement patterns do not differ substantially between barefoot and shod running, and that the effects of these interventions are subject specific. The result of this in vivo study contrasts with previous investigations using skin and shoe mounted markers and suggests that these discrepancies may be the result of the overestimation with externally mounted markers.

  2. Thermally Insulating, Kinematic Tensioned-Fiber Suspension

    NASA Technical Reports Server (NTRS)

    Voellmer, George M.

    2004-01-01

    A salt pill and some parts of a thermally insulating, kinematic suspension system that holds the salt pill rigidly in an adiabatic-demagnetization refrigerator (ADR) is presented. "Salt pill" in this context denotes a unit comprising a cylindrical container, a matrix of gold wires in the container, and a cylinder of ferric ammonium alum (a paramagnetic salt) that has been deposited on the wires. The structural members used in this system for both thermal insulation and positioning are aromatic polyamide fibers (Kevlar(R) or equivalent) under tension. This suspension system is designed to satisfy several special requirements to ensure the proper operation of the ADR. These requirements are to (1) maintain the salt pill at a specified position within the cylindrical bore of an electromagnet; (2) prevent vibrations, which would cause dissipation of heat in the salt pill; and (3) minimize the conduction of heat from the electromagnet bore and other neighboring objects to the salt pill; all while (4) protecting the salt pill (which is fragile) against all tensile and bending loads other than those attributable to its own weight. In addition, the system is required to consist of two subsystems -- one for the top end and one for the bottom end of the salt pill -- that can be assembled and tensioned separately from each other and from the salt pill, then later attached to the salt pill.

  3. SHIELD: Neutral Gas Kinematics and Dynamics

    NASA Astrophysics Data System (ADS)

    McNichols, Andrew T.; Teich, Yaron G.; Nims, Elise; Cannon, John M.; Adams, Elizabeth A. K.; Bernstein-Cooper, Elijah Z.; Giovanelli, Riccardo; Haynes, Martha P.; Józsa, Gyula I. G.; McQuinn, Kristen B. W.; Salzer, John J.; Skillman, Evan D.; Warren, Steven R.; Dolphin, Andrew; Elson, E. C.; Haurberg, Nathalie; Ott, Jürgen; Saintonge, Amelie; Cave, Ian; Hagen, Cedric; Huang, Shan; Janowiecki, Steven; Marshall, Melissa V.; Thomann, Clara M.; Van Sistine, Angela

    2016-11-01

    We present kinematic analyses of the 12 galaxies in the “Survey of H i in Extremely Low-mass Dwarfs” (SHIELD). We use multi-configuration interferometric observations of the H i 21 cm emission line from the Karl G. Jansky Very Large Array (VLA)22 to produce image cubes at a variety of spatial and spectral resolutions. Both two- and three-dimensional fitting techniques are employed in an attempt to derive inclination-corrected rotation curves for each galaxy. In most cases, the comparable magnitudes of velocity dispersion and projected rotation result in degeneracies that prohibit unambiguous circular velocity solutions. We thus make spatially resolved position-velocity cuts, corrected for inclination using the stellar components, to estimate the circular rotation velocities. We find {v}{circ} ≤slant 30 km s-1 for the entire survey population. Baryonic masses are calculated using single-dish H i fluxes from Arecibo and stellar masses derived from HST and Spitzer imaging. Comparison is made with total dynamical masses estimated from the position-velocity analysis. The SHIELD galaxies are then placed on the baryonic Tully-Fisher relation. There exists an empirical threshold rotational velocity, V {}{rot} < 15 km s-1, below which current observations cannot differentiate coherent rotation from pressure support. The SHIELD galaxies are representative of an important population of galaxies whose properties cannot be described by current models of rotationally dominated galaxy dynamics.

  4. Kinematic dynamo, supersymmetry breaking, and chaos

    NASA Astrophysics Data System (ADS)

    Ovchinnikov, Igor V.; Enßlin, Torsten A.

    2016-04-01

    The kinematic dynamo (KD) describes the growth of magnetic fields generated by the flow of a conducting medium in the limit of vanishing backaction of the fields onto the flow. The KD is therefore an important model system for understanding astrophysical magnetism. Here, the mathematical correspondence between the KD and a specific stochastic differential equation (SDE) viewed from the perspective of the supersymmetric theory of stochastics (STS) is discussed. The STS is a novel, approximation-free framework to investigate SDEs. The correspondence reported here permits insights from the STS to be applied to the theory of KD and vice versa. It was previously known that the fast KD in the idealistic limit of no magnetic diffusion requires chaotic flows. The KD-STS correspondence shows that this is also true for the diffusive KD. From the STS perspective, the KD possesses a topological supersymmetry, and the dynamo effect can be viewed as its spontaneous breakdown. This supersymmetry breaking can be regarded as the stochastic generalization of the concept of dynamical chaos. As this supersymmetry breaking happens in both the diffusive and the nondiffusive cases, the necessity of the underlying SDE being chaotic is given in either case. The observed exponentially growing and oscillating KD modes prove physically that dynamical spectra of the STS evolution operator that break the topological supersymmetry exist with both real and complex ground state eigenvalues. Finally, we comment on the nonexistence of dynamos for scalar quantities.

  5. GLOBAL H I KINEMATICS IN DWARF GALAXIES

    SciTech Connect

    Stilp, Adrienne M.; Dalcanton, Julianne J.; Warren, Steven R.; Skillman, Evan; Ott, Juergen; Koribalski, Baerbel

    2013-03-10

    H I line widths are typically interpreted as a measure of interstellar medium turbulence, which is potentially driven by star formation (SF). In an effort to better understand the possible connections between line widths and SF, we have characterized H I kinematics in a sample of nearby dwarf galaxies by co-adding line-of-sight spectra after removing the rotational velocity to produce average global H I line profiles. These ''superprofiles'' are composed of a central narrow peak ({approx}6-10 km s{sup -1}) with higher-velocity wings to either side that contain {approx}10%-15% of the total flux. The superprofiles are all very similar, indicating a universal global H I profile for dwarf galaxies. We compare characteristics of the superprofiles to various galaxy properties, such as mass and measures of SF, with the assumption that the superprofile represents a turbulent peak with energetic wings to either side. We use these quantities to derive average scale heights for the sample galaxies. When comparing to physical properties, we find that the velocity dispersion of the central peak is correlated with ({Sigma}{sub HI}). The fraction of mass and characteristic velocity of the high-velocity wings are correlated with measures of SF, consistent with the picture that SF drives surrounding H I to higher velocities. While gravitational instabilities provide too little energy, the SF in the sample galaxies does provide enough energy through supernovae, with realistic estimates of the coupling efficiency, to produce the observed superprofiles.

  6. Kinematic analysis of rope skipper's stability

    NASA Astrophysics Data System (ADS)

    Ab Ghani, Nor Atikah; Rambely, Azmin Sham

    2014-06-01

    There are various kinds of jumping that can be done while performing rope skipping activity. This activity was always associated with injury. But, if the rope skipper can perform the activity in a right way, it is believed that the injury might be reduced. The main purpose of this paper is to observe the stability of rope skipper from a biomechanics perspective, which are the centre of mass, angle at the ankle, knee and hip joints and also the trajectory for the ipsilateral leg between the two types of skip which is one leg and two legs. Six healthy, physically active subject, two males and four females (age: 8.00±1.25 years, weight: 17.90±6.85 kg and height: 1.22±0.08 m) participated in this study. Kinematic data of repeated five cycles of rope skipping activity was captured by using Vicon Nexus system. Based on the data collected, skipping with two legs shows more stable behavior during preparation, flight and landing phases. It is concluded that landing on the balls of the feet, lowering the trajectory positions of the feet from the ground as well as flexion of each joint which would reduce the injury while landing.

  7. On the Kinematics of Undulator Girder Motion

    SciTech Connect

    Welch, J; /SLAC

    2011-08-18

    The theory of rigid body kinematics is used to derive equations that govern the control and measurement of the position and orientation of undulator girders. The equations form the basis of the girder matlab software on the LCLS control system. The equations are linear for small motion and easily inverted as desired. For reference, some relevant girder geometrical data is also given. Equations 6-8 relate the linear potentiometer readings to the motion of the girder. Equations 9-11 relate the cam shaft angles to the motion of the girder. Both sets are easily inverted to either obtain the girder motion from the angles or readings, or, to find the angles and readings that would give a desired motion. The motion of any point on the girder can be calculated by applying either sets of equations to the two cam-planes and extrapolating in the z coordinate using equation 19. The formulation of the equations is quite general and easily coded via matrix and vector methods. They form the basis of the girder matlab software on the LCLS control system.

  8. Kinematics and trajectory generation for MIRADAS arms

    NASA Astrophysics Data System (ADS)

    Sabater, J.; Gómez, J. M.; Torra, J.; López, M.; Raines, S. N.; Eikenberry, S. S.

    2015-05-01

    The Mid-resolution InfRAreD Astronomical Spectrograph (MIRADAS) is a NIR multi-object spectrograph for the Gran Telescopio Canarias (GTC). The instrument has a multiplexing system (MXS) that enables the simultaneous observation of twenty objects located within its field of view. These user selected targets are acquired by twenty deployable robotic probe arms with pickoff mirror optics operating at cryogenic temperatures. The MIRADAS probe arm is a close-loop mechanism designed with optics simplicity in mind, presenting good stability when it is operated upside down. Calculating optimum collision-free trajectories requires a good knowledge of the MIRADAS arm behavior based on its geometry and its mechanical constraints. This study introduces a geometric model for the two degree-of-freedom (DoF) mechanism, including solutions for the forward and inverse kinematics problem. The concepts of zone-of-avoidance (ZoA), workspace and envelope of MIRADAS arm are presented and studied. Finally, the paper proposes two different patrolling approaches that can be exploited when planning trajectories.

  9. Kinematic mental simulations in abduction and deduction

    PubMed Central

    Khemlani, Sangeet Suresh; Mackiewicz, Robert; Bucciarelli, Monica; Johnson-Laird, Philip N.

    2013-01-01

    We present a theory, and its computer implementation, of how mental simulations underlie the abductions of informal algorithms and deductions from these algorithms. Three experiments tested the theory’s predictions, using an environment of a single railway track and a siding. This environment is akin to a universal Turing machine, but it is simple enough for nonprogrammers to use. Participants solved problems that required use of the siding to rearrange the order of cars in a train (experiment 1). Participants abduced and described in their own words algorithms that solved such problems for trains of any length, and, as the use of simulation predicts, they favored “while-loops” over “for-loops” in their descriptions (experiment 2). Given descriptions of loops of procedures, participants deduced the consequences for given trains of six cars, doing so without access to the railway environment (experiment 3). As the theory predicts, difficulty in rearranging trains depends on the numbers of moves and cars to be moved, whereas in formulating an algorithm and deducing its consequences, it depends on the Kolmogorov complexity of the algorithm. Overall, the results corroborated the use of a kinematic mental model in creating and testing informal algorithms and showed that individuals differ reliably in the ability to carry out these tasks. PMID:24082090

  10. Restraints and occupant kinematics in vehicular rollovers.

    PubMed

    Meyer, Steven E; Herbst, Brian; Forrest, Stephen; Syson, Stephen R; Sances, Anthony; Kumaresan, Srirangam

    2002-01-01

    Occupant kinematics and the potential for injury in vehicular rollover crashes are dramatically affected by various restraint system characteristics. This study reviews previous research that utilized various methodologies and test fixtures to evaluate restrained occupant motions, primarily in the vertical direction, during both inverted and quasi-static simulated rollover environments. Additional laboratory tests were conducted in order to understand the static and dynamic excursion of restrained humans and surrogates in typical production motor vehicles under inverted circumstances. These tests indicated that volunteer occupants restrained within a complete vehicle by typical production 3 point seat belts will move vertically towards the vehicle roof structure by approximately 50-150 mm in production vehicles, depending on occupant size and belt configuration, when inverted and subjected to a static 1 g acceleration. Dynamic inverted vehicle drop testing in 3-point belt production vehicles, resulting in 4 to 11 g impacts, resulted in surrogates moving only about an additional 23 to 55 mm beyond the static inverted 1 g excursions.

  11. Feeding underground: kinematics of feeding in caecilians.

    PubMed

    Herrel, Anthony; Measey, G John

    2012-11-01

    Caecilians are limbless amphibians that have evolved distinct cranial and postcranial specializations associated with a burrowing lifestyle. Observations on feeding behavior are rare and restricted to above-ground feeding in laboratory conditions. Here we report data on feeding in tunnels using both external video and X-ray recordings of caecilians feeding on invertebrate prey. Our data show feeding kinematics similar to those previously reported, including the pronounced neck bending observed during above-ground feeding. Our data illustrate, however, that caecilians may be much faster than previously suspected, with lunge speeds of up to 7 cm sec(-1). Although gape cycles are often slow (0.67 ± 0.29 sec), rapid jaw closure is observed during prey capture, with cycle times and jaw movement velocities similar to those observed in other terrestrial tetrapods. Finally, our data suggest that gape angles may be large (64.8 ± 18°) and that gape profiles are variable, often lacking distinct slow and fast opening and closing phases. These data illustrate the importance of recording naturalistic feeding behavior and shed light on how these animals are capable of capturing and processing prey in constrained underground environments. Additional data on species with divergent cranial morphologies would be needed to better understand the co-evolution between feeding, burrowing, and cranial design in caecilians.

  12. Manipulating the edge of instability

    PubMed Central

    Venkadesan, Madhusudhan; Guckenheimer, John; Valero-Cuevas, Francisco J.

    2009-01-01

    We investigate the integration of visual and tactile sensory input for dynamic manipulation. Our experimental data and computational modeling reveal that time-delays are as critical to task-optimal multisensory integration as sensorimotor noise. Our focus is a dynamic manipulation task “at the edge of instability.” Mathematical bifurcation theory predicts that this system will exhibit well-classified low-dimensional dynamics in this regime. The task was using the thumbpad to compress a slender spring prone to buckling as far as possible, just shy of slipping. As expected from bifurcation theory, principal components analysis gives a projection of the data onto a low dimensional subspace that captures 91-97% of its variance. In this subspace, we formulate a low-order model for the brain+hand+spring dynamics based on known mechanical and neurophysiological properties of the system. By systematically occluding vision and anesthetically blocking thumbpad sensation in 12 consenting subjects, we found that vision contributed to dynamic manipulation only when thumbpad sensation was absent. The reduced ability of the model system to compress the spring with absent sensory channels closely resembled the experimental results. Moreover, we found that the model reproduced the contextual usefulness of vision only if we took account of time-delays. Our results shed light on critical features of dynamic manipulation distinct from those of static pinch, as well as the mechanism likely responsible for loss of manual dexterity and increased reliance on vision when age or neuromuscular disease increase noisiness and/or time-delays during sensorimotor integration. PMID:17400231

  13. A Magnified View of the Kinematics and Morphology of RCSGA 032727-132609: Zooming in on a Merger at z = 1.7

    NASA Technical Reports Server (NTRS)

    Wuyts, Eva; Rigby, Jane R.; Gladders, Michael D.; Sharon, Keren

    2014-01-01

    We present a detailed analysis of multi-wavelength Hubble Space Telescope/Wide Field Camera 3 (WFC3) imaging and Keck/OSIRIS near-infrared adaptive optics-assisted integral field spectroscopy for a highly magnified lensed galaxy at z = 1.70. This young starburst is representative of ultraviolet-selected star-forming galaxies (SFGs) at z approx. 2 and contains multiple individual star-forming regions. Due to the lensing magnification, we can resolve spatial scales down to 100 pc in the source plane of the galaxy. The velocity field shows disturbed kinematics suggestive of an ongoing interaction and there is a clear signature of a tidal tail. We constrain the age, reddening, star formation rate, and stellar mass of the star-forming clumps from spectral energy distribution (SED) modeling of the WFC3 photometry and measure their H(alpha) luminosity, metallicity, and outflow properties from the OSIRIS data.With strong star-formation-driven outflows in four clumps, RCSGA0327 is the first high-redshift SFG at stellar mass <10(exp 10) Stellar Mass with spatially resolved stellar winds. We compare the H(alpha) luminosities, sizes, and dispersions of the star-forming regions with other high-z clumps as well as local giant H(II) regions and find no evidence for increased clump star formation surface densities in interacting systems, unlike in the local universe. Spatially resolved SED modeling unveils an established stellar population at the location of the largest clump and a second mass concentration near the edge of the system that is not detected in H(alpha) emission. This suggests a picture of an equal-mass mixed major merger, which has not triggered a new burst of star formation or caused a tidal tail in the gas-poor component.

  14. A Magnified View of the Kinematics and Morphology of RCSGA 032727-132609: Zooming in on a Merger at z = 1.7

    NASA Astrophysics Data System (ADS)

    Wuyts, Eva; Rigby, Jane R.; Gladders, Michael D.; Sharon, Keren

    2014-02-01

    We present a detailed analysis of multi-wavelength Hubble Space Telescope/Wide Field Camera 3 (WFC3) imaging and Keck/OSIRIS near-infrared adaptive optics-assisted integral field spectroscopy for a highly magnified lensed galaxy at z = 1.70. This young starburst is representative of ultraviolet-selected star-forming galaxies (SFGs) at z ~ 2 and contains multiple individual star-forming regions. Due to the lensing magnification, we can resolve spatial scales down to 100 pc in the source plane of the galaxy. The velocity field shows disturbed kinematics suggestive of an ongoing interaction and there is a clear signature of a tidal tail. We constrain the age, reddening, star formation rate, and stellar mass of the star-forming clumps from spectral energy distribution (SED) modeling of the WFC3 photometry and measure their Hα luminosity, metallicity, and outflow properties from the OSIRIS data. With strong star-formation-driven outflows in four clumps, RCSGA0327 is the first high-redshift SFG at stellar mass <1010 M ⊙ with spatially resolved stellar winds. We compare the Hα luminosities, sizes, and dispersions of the star-forming regions with other high-z clumps as well as local giant H II regions and find no evidence for increased clump star formation surface densities in interacting systems, unlike in the local universe. Spatially resolved SED modeling unveils an established stellar population at the location of the largest clump and a second mass concentration near the edge of the system that is not detected in Hα emission. This suggests a picture of an equal-mass mixed major merger, which has not triggered a new burst of star formation or caused a tidal tail in the gas-poor component.

  15. A magnified view of the kinematics and morphology of RCSGA 032727-132609: Zooming in on a merger at z = 1.7

    SciTech Connect

    Wuyts, Eva; Rigby, Jane R.; Gladders, Michael D.; Sharon, Keren

    2014-02-01

    We present a detailed analysis of multi-wavelength Hubble Space Telescope/Wide Field Camera 3 (WFC3) imaging and Keck/OSIRIS near-infrared adaptive optics-assisted integral field spectroscopy for a highly magnified lensed galaxy at z = 1.70. This young starburst is representative of ultraviolet-selected star-forming galaxies (SFGs) at z ∼ 2 and contains multiple individual star-forming regions. Due to the lensing magnification, we can resolve spatial scales down to 100 pc in the source plane of the galaxy. The velocity field shows disturbed kinematics suggestive of an ongoing interaction and there is a clear signature of a tidal tail. We constrain the age, reddening, star formation rate, and stellar mass of the star-forming clumps from spectral energy distribution (SED) modeling of the WFC3 photometry and measure their Hα luminosity, metallicity, and outflow properties from the OSIRIS data. With strong star-formation-driven outflows in four clumps, RCSGA0327 is the first high-redshift SFG at stellar mass <10{sup 10} M {sub ☉} with spatially resolved stellar winds. We compare the Hα luminosities, sizes, and dispersions of the star-forming regions with other high-z clumps as well as local giant H II regions and find no evidence for increased clump star formation surface densities in interacting systems, unlike in the local universe. Spatially resolved SED modeling unveils an established stellar population at the location of the largest clump and a second mass concentration near the edge of the system that is not detected in Hα emission. This suggests a picture of an equal-mass mixed major merger, which has not triggered a new burst of star formation or caused a tidal tail in the gas-poor component.

  16. Elastically Deformable Side-Edge Link for Trailing-Edge Flap Aeroacoustic Noise Reduction

    NASA Technical Reports Server (NTRS)

    Khorrami, Mehdi R. (Inventor); Lockard, David P. (Inventor); Moore, James B. (Inventor); Su, Ji (Inventor); Turner, Travis L. (Inventor); Lin, John C. (Inventor); Taminger, Karen M. (Inventor); Kahng, Seun K. (Inventor); Verden, Scott A. (Inventor)

    2014-01-01

    A system is provided for reducing aeroacoustic noise generated by an aircraft having wings equipped with trailing-edge flaps. The system includes a plurality of elastically deformable structures. Each structure is coupled to and along one of the side edges of one of the trailing-edge flaps, and is coupled to a portion of one of the wings that is adjacent to the one of the side edges. The structures elastically deform when the trailing-edge flaps are deployed away from the wings.

  17. A learning-based markerless approach for full-body kinematics estimation in-natura from a single image.

    PubMed

    Drory, Ami; Li, Hongdong; Hartley, Richard

    2017-04-11

    We present a supervised machine learning approach for markerless estimation of human full-body kinematics for a cyclist from an unconstrained colour image. This approach is motivated by the limitations of existing marker-based approaches restricted by infrastructure, environmental conditions, and obtrusive markers. By using a discriminatively learned mixture-of-parts model, we construct a probabilistic tree representation to model the configuration and appearance of human body joints. During the learning stage, a Structured Support Vector Machine (SSVM) learns body parts appearance and spatial relations. In the testing stage, the learned models are employed to recover body pose via searching in a test image over a pyramid structure. We focus on the movement modality of cycling to demonstrate the efficacy of our approach. In natura estimation of cycling kinematics using images is challenging because of human interaction with a bicycle causing frequent occlusions. We make no assumptions in relation to the kinematic constraints of the model, nor the appearance of the scene. Our technique finds multiple quality hypotheses for the pose. We evaluate the precision of our method on two new datasets using loss functions. Our method achieves a score of 91.1 and 69.3 on mean Probability of Correct Keypoint (PCK) measure and 88.7 and 66.1 on the Average Precision of Keypoints (APK) measure for the frontal and sagittal datasets respectively. We conclude that our method opens new vistas to robust user-interaction free estimation of full body kinematics, a prerequisite to motion analysis.

  18. Kinematics Around the Non-Thermal Superbubble in IC10

    NASA Astrophysics Data System (ADS)

    Bullejos, A.; Rosado, M.

    2002-02-01

    We study the kinematics around a non-thermal superbubble found by Yang & Skillman. Considering the H II and [S II] profiles, we find that between 3 and 6 supernovae are required to form this superbubble.

  19. Kinematic distributions for electron pair production by muons

    NASA Technical Reports Server (NTRS)

    Linsker, R.

    1972-01-01

    Cross sections and kinematic distributions for the trident production process plus or negative muon plus charge yields plus or minus muon plus electron plus positron plus charge (with charge = dipion moment and Fe) are given for beam energies of 100 to 300 GeV at fixed (electron positron) masses from 5 to 15 GeV. This process is interesting as a test of quantum electrodynamics at high energies, and in particular as a test of the form of the photon propagator at large timelike (four-momentum) squared. For this purpose, it is desirable to impose kinematic cuts that favor those Bethe-Heitler graphs which contain a timelike photon propagator. It is found that there are substantial differences between the kinematic distributions for the full Bethe-Heitler matrix element and the distributions for the two timelike-photon graphs alone; these differences can be exploited in the selection of appropriate kinematic cuts.

  20. The Kinematics of the Lag-Luminosity Relationship

    SciTech Connect

    Salmonson, J D

    2004-03-17

    Herein I review the argument that kinematics, i.e. relativistic motions of the emitting source in gamma-ray bursts (GRBs), are the cause of the lag-luminosity relationship observed in bursts with known redshifts.

  1. Red edge spectral measurements from sugar maple leaves

    NASA Technical Reports Server (NTRS)

    Vogelmann, J. E.; Rock, B. N.; Moss, D. M.

    1993-01-01

    Many sugar maple stands in the northeastern United States experienced extensive insect damage during the 1988 growing season. Chlorophyll data and high spectral resolution spectrometer laboratory reflectance data were acquired for multiple collections of single detached sugar maple leaves variously affected by the insect over the 1988 growing season. Reflectance data indicated consistent and diagnostic differences in the red edge portion (680-750 nm) of the spectrum among the various samples and populations of leaves. These included differences in the red edge inflection point (REIP), a ratio of reflectance at 740-720 nm (RE3/RE2), and a ratio of first derivative values at 715-705 nm (D715/D705). All three red edge parameters were highly correlated with variation in total chlorophyll content. Other spectral measures, including the Normalized Difference Vegetation Index (NDVI) and the Simple Vegetation Index Ratio (VI), also varied among populations and over the growing season, but did not correlate well with total chlorophyll content. Leaf stacking studies on light and dark backgrounds indicated REIP, RE3/RE2 and D715/D705 to be much less influenced by differences in green leaf biomass and background condition than either NDVI or VI.

  2. Kinematic analysis of platform-type robotic manipulators

    NASA Astrophysics Data System (ADS)

    Shi, Xiaolun

    New methods are developed for the kinematic analysis of serial and platform-type parallel robotic manipulators, including forward and inverse kinematic solutions, singularity identifications and workspace evaluation. Differences between serial and platform-type parallel manipulators, which can provide substantially improved end-point rigidity compared with the conventional serial robotic arms, are addressed. The problem of determining the screw parameters of rigid body motion from initial and final position data is discussed, as a basis to search for a general and efficient procedure to solve the complex forward kinematics problem of platform-type manipulators. Several Screw-Theory based approaches for solving the inverse instantaneous problem of 6 DOF serial manipulators are studied and compared in terms of their computational efficiency, accuracy, sensitivity to data error and capability of dealing with singularities. A modified Vector Decomposition method is then proposed for solving the IIK problem and for singularity analysis of serial kinematic chains, the method is especially effective when applied to the wrist partitioned serial manipulators, which are essential components to any platform-type parallel manipulators. By using the data of three point positions, velocities, and accelerations of the end effector a general method is developed for solving the forward kinematics problem, including position, velocity and acceleration kinematics, of platform-type manipulators. The solution procedure can be applied to a wide variety of platform-type manipulators such as the 6 DOF Steward Platform manipulator and other models. It is found that while the solution for the forward position kinematics of a platform-type manipulator can be obtained by solving a non-linear system of equations, the closed-form solutions for forward rate and acceleration kinematics can be found by solving a system of linear equations. Based on the proposed kinematic formulations, an algorithm

  3. Elucidation of kinematical and dynamical structure of the Galactic bulge

    NASA Astrophysics Data System (ADS)

    Yano, T.; Gouda, N.; Ueda, H.; Koyama, H.; Kan-ya, Y.; Taruya, A.

    2008-07-01

    Future space mission of astrometric satellite, GAIA and JASMINE (Japan Astrometry Satellite Mission for Infrared Exploration), will produce astrometric parameter, such as positions, parallaxes, and proper motions of stars in the Galactic bulge. Then kinematical information will be obtained in the future. Accordingly it is expected that our understanding of the dynamical structure will be greatly improved. Therefore it is important to make a method to construct a kinematical and dynamical structure of the Galactic bulge immediately.

  4. Interplanetary stream magnetism: Kinematic effects. [solar magnetic fields and wind

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Barouch, E.

    1974-01-01

    The particle density, and the magnetic field intensity and direction are calculated in corotating streams of the solar wind, assuming that the solar wind velocity is constant and radial and that its azimuthal variations are not two rapid. The effects of the radial velocity profile in corotating streams on the magnetic fields were examined using kinematic approximation and a variety of field configurations on the inner boundary. Kinematic and dynamic effects are discussed.

  5. The Relationships between Logical Thinking, Gender, and Kinematics Graph Interpretation Skills

    ERIC Educational Resources Information Center

    Bektasli, Behzat; White, Arthur L.

    2012-01-01

    Problem Statement: Kinematics is one of the topics in physics where graphs are used broadly. Kinematics includes many abstract formulas, and students usually try to solve problems with those formulas. However, using a kinematics graph instead of formulas might be a better option for problem solving in kinematics. Graphs are abstract…

  6. Automatic barcode recognition method based on adaptive edge detection and a mapping model

    NASA Astrophysics Data System (ADS)

    Yang, Hua; Chen, Lianzheng; Chen, Yifan; Lee, Yong; Yin, Zhouping

    2016-09-01

    An adaptive edge detection and mapping (AEDM) algorithm to address the challenging one-dimensional barcode recognition task with the existence of both image degradation and barcode shape deformation is presented. AEDM is an edge detection-based method that has three consecutive phases. The first phase extracts the scan lines from a cropped image. The second phase involves detecting the edge points in a scan line. The edge positions are assumed to be the intersecting points between a scan line and a corresponding well-designed reference line. The third phase involves adjusting the preliminary edge positions to more reasonable positions by employing prior information of the coding rules. Thus, a universal edge mapping model is established to obtain the coding positions of each edge in this phase, followed by a decoding procedure. The Levenberg-Marquardt method is utilized to solve this nonlinear model. The computational complexity and convergence analysis of AEDM are also provided. Several experiments were implemented to evaluate the performance of AEDM algorithm. The results indicate that the efficient AEDM algorithm outperforms state-of-the-art methods and adequately addresses multiple issues, such as out-of-focus blur, nonlinear distortion, noise, nonlinear optical illumination, and situations that involve the combinations of these issues.

  7. The multiform motor cortical output: Kinematic, predictive and response coding.

    PubMed

    Sartori, Luisa; Betti, Sonia; Chinellato, Eris; Castiello, Umberto

    2015-09-01

    Observing actions performed by others entails a subliminal activation of primary motor cortex reflecting the components encoded in the observed action. One of the most debated issues concerns the role of this output: Is it a mere replica of the incoming flow of information (kinematic coding), is it oriented to anticipate the forthcoming events (predictive coding) or is it aimed at responding in a suitable fashion to the actions of others (response coding)? The aim of the present study was to disentangle the relative contribution of these three levels and unify them into an integrated view of cortical motor coding. We combined transcranial magnetic stimulation (TMS) and electromyography recordings at different timings to probe the excitability of corticospinal projections to upper and lower limb muscles of participants observing a soccer player performing: (i) a penalty kick straight in their direction and then coming to a full stop, (ii) a penalty kick straight in their direction and then continuing to run, (iii) a penalty kick to the side and then continuing to run. The results show a modulation of the observer's corticospinal excitability in different effectors at different times reflecting a multiplicity of motor coding. The internal replica of the observed action, the predictive activation, and the adaptive integration of congruent and non-congruent responses to the actions of others can coexist in a not mutually exclusive way. Such a view offers reconciliation among different (and apparently divergent) frameworks in action observation literature, and will promote a more complete and integrated understanding of recent findings on motor simulation, motor resonance and automatic imitation.

  8. Kinematic indicators on active normal faults in Western Turkey

    NASA Astrophysics Data System (ADS)

    Hancock, P. L.; Barka, A. A.

    Quaternary normal fault zones in western Turkey comprise multiple slip planes and zone-parallel layers of fault breccia. They also contain several little-known kinematic indicators that are probably typical of many formed at shallow levels in extending terrains. The recent exhumation by contractors of about 2000 m 2 of slip planes in a SSE-dipping fault zone separating Quaternary colluvium from bedrock carbonates at Yavansu (7 km SE of Kuşadasi) permits an unusually complete inventory of the indicators to be compiled. The most spectacular indicators are metre-scale 69°W-pitching corrugations in slip planes and recemented breccia sheets underlying them. Corrugations, characterized by sinusoidal profiles normal to their long axes and, less commonly, culminations and depression along their axes possibly developed as a result of upwards-propagating slip planes seeking undemanding pathways through heterogeneous fault-precursor breccias that formed in advance of tip lines. Parallel to corrugation long axes are those of gutters, flat-floored, sleep-sided channels a few centimetres wide, probably related to the abrasion of subslip-plane breccia sheets. Centimetre-scale tool tracks scored in the uppermost subslip-plane breccia sheet by resistant colluvial clasts are irregular at their proximal ends but distally they swing into alignment with corrugation axes. Frictional-wear striae, centimetres long but only a few millimetres wide and pitching 78°W, are superimposed on the other slip-parallel lineations. Comb fractures nearly perpendicular to slip planes define an intersection lineation which is normal to corrugation axes. Fault-plane solutions of earthquakes on SSE-dipping active faults in the West Anatolian extensional province indicate that mainly normal, combined with minor dextral slip is the dominant mode, a conclusion in accord with the sense of slip inferred from the indicators exposed on the Yavansu slip planes.

  9. Determination of space use by laying hens using kinematic analysis.

    PubMed

    Mench, Joy A; Blatchford, Richard A

    2014-04-01

    Two states in the United States now have legislation requiring that laying hens be provided with sufficient space to perform particular behaviors. To provide a framework for translating these performance standards into a space requirement, kinematic analysis was used to measure the amount of space needed for White Leghorn hens to stand, turn around 180°, lie down, and wing flap. Hyline W-36 hens (n = 9) were marked on the tops of their heads and the tips of both wings and 3 toes with black livestock marker. Each hen was then placed in a floor pen (91.4 × 91.4 cm) and filmed using 2 high-speed cameras. The resulting images were processed using a software program that generated 3-dimensional space use for each behavior. Because none of the hens lay down in the test pen, the 2-dimensional space required for lying was determined by superimposing a grid over videos of the hens lying down in their home cages. On average, hens required a mean area of 563 (± 8) cm(2) to stand, 1,316 (± 23) cm(2) to turn around, 318 (± 6) cm(2) to lie down, and 1,693 (± 136) cm(2) to wing flap. The mean heights used were 34.8 (± 1.3) cm for standing, 38.6 (± 2.3) cm for turning, and 49.5 (± 1.8) cm for wing flapping. However, space requirements for hens housed in multiple-hen groups in cage or noncage systems cannot be based simply on information about the space required for local movement by a single hen. It must also incorporate consideration of the tendency of hens in a flock to synchronize their behaviors. In addition, it must include not just local movement space but also the space that hens may need to use for longer-distance movements to access resources such as food, water, perches, and nest boxes.

  10. Kinematic Chains in Ski Jumping In-run Posture.

    PubMed

    Janurová, Eva; Janura, Miroslav; Cabell, Lee; Svoboda, Zdeněk; Vařeka, Ivan; Elfmark, Milan

    2013-12-18

    The concept of kinematic chains has been systematically applied to biological systems since the 1950s. The course of a ski jump can be characterized as a change between closed and open kinematic chains. The purpose of this study was to determine a relationship between adjacent segments within the ski jumper's body's kinematic chain during the in-run phase of the ski jump. The in-run positions of 267 elite male ski jumpers who participated in the FIS World Cup events in Innsbruck, Austria, between 1992 and 2001 were analyzed (656 jumps). Two-dimensional (2-D) kinematic data were collected from the bodies of the subjects. Relationships between adjacent segments of the kinematic chain in the ski jumper's body at the in-run position are greater nearer the chain's ground contact. The coefficient of determination between the ankle and knee joint angles is 0.67. Changes in the segments' positions in the kinematic chain of the ski jumper's body are stable during longitudinal assessment. Changes in shank and thigh positions, in the sense of increase or decrease, are the same.

  11. Dynamic activity dependence of in vivo normal knee kinematics.

    PubMed

    Moro-oka, Taka-aki; Hamai, Satoshi; Miura, Hiromasa; Shimoto, Takeshi; Higaki, Hidehiko; Fregly, Benjamin J; Iwamoto, Yukihide; Banks, Scott A

    2008-04-01

    Dynamic knee kinematics were analyzed for normal knees in three activities, including two different types of maximum knee flexion. Continuous X-ray images of kneel, squat, and stair climb motions were taken using a large flat panel detector. CT-derived bone models were used for model registration-based 3D kinematic measurement. Three-dimensional joint kinematics and contact locations were determined using three methods: bone-fixed coordinate systems, interrogation of CT-based bone model surfaces, and interrogation of MR-based articular cartilage model surfaces. The femur exhibited gradual external rotation throughout the flexion range. Tibiofemoral contact exhibited external rotation, with contact locations translating posterior while maintaining 15 degrees to 20 degrees external rotation from 20 degrees to 80 degrees of flexion. From 80 degrees to maximum flexion, contact locations showed a medial pivot pattern. Kinematics based on bone-fixed coordinate systems differed from kinematics based on interrogation of CT and MR surfaces. Knee kinematics varied significantly by activity, especially in deep flexion. No posterior subluxation occurred for either femoral condyle in maximum knee flexion. Normal knees accommodate a range of motions during various activities while maintaining geometric joint congruency.

  12. A Deep Chandra Observation of the Centaurus Cluster:Bubbles, Filaments and Edges

    SciTech Connect

    Fabian, A.C.

    2005-03-14

    X-ray images and gas temperatures taken from a deep {approx}200 ks Chandra observation of the Centaurus cluster are presented. Multiple inner bubbles and outer semicircular edges are revealed, together with wispy filaments of soft X-ray emitting gas. The frothy central structure and eastern edge are likely due to the central radio source blowing bubbles in the intracluster gas. The semicircular edges to the surface brightness maps 32 kpc to the east and 17.5 kpc to the west are marked by sharp temperature increases and abundance drops. The edges could be due to sloshing motions of the central potential, or are possibly enhanced by earlier radio activity. The high abundance of the innermost gas (about 2.5 times Solar) limits the amount of diffusion and mixing taking place.

  13. Edge effects in the magnetic interference pattern of a ballistic SNS junction

    NASA Astrophysics Data System (ADS)

    Meier, Hendrik; Fal'ko, Vladimir I.; Glazman, Leonid I.

    2016-05-01

    We investigate the Josephson critical current Ic(Φ ) of a wide superconductor-normal metal-superconductor (SNS) junction as a function of the magnetic flux Φ threading it. Electronic trajectories reflected from the side edges alter the function Ic(Φ ) as compared to the conventional Fraunhofer-type dependence. At weak magnetic fields, B ≲Φ0/d2 , the edge effect lifts zeros in Ic(Φ ) and gradually shifts the minima of that function toward half-integer multiples of the flux quantum. At B >Φ0/d2 , the edge effect leads to an accelerated decay of the critical current Ic(Φ ) with increasing Φ . At larger fields, eventually, the system is expected to cross into a regime of "classical" mesoscopic fluctuations that is specific for wide ballistic SNS junctions with rough edges.

  14. Comparative Study of Edge Detectors in case of Echocardiographic Images

    NASA Astrophysics Data System (ADS)

    Saini, Kalpana; Dewal, M. L.; Rohit, Manoj Kumar

    2010-11-01

    In this paper we compare different edge detectors based on peak signal to noise ratio on Echocardiographic images. Edge detection is a critical element in image processing, since edges contain a major function of image information. The function of edge detection is to identify the boundaries of homogeneous regions in an image based on properties such as intensity and texture.We have taken Perwitt edge detector, Robarts edge detector, LoG edge detector, Canny edge detector, and Sobel edge detector for this comparison and study.

  15. Kinematical Modeling of WARPS in the H i Disks of Galaxies

    NASA Astrophysics Data System (ADS)

    Christodoulou, Dimitris M.; Tohline, Joel E.; Steiman-Cameron, Thomas Y.

    1993-10-01

    In order to gain an appreciation for the general structure of warped gas layers in galaxies, we have constructed kinematical, tilted-ring models of 21 galaxies for which detailed H I observations already exist in the literature. In this paper we present results for the 15 normal spiral galaxies of this sample that are not viewed edge-on. A comparison between our models and tilted-ring models of the same galaxies previously constructed by other authors shows that there is generally good agreement. We make an attempt to unify the notation of diff&rent authors who have published radio observations and/or kinematical models of individual galaxies in this sample. We also suggest how, in future work of this nature, model parameters should be presented and referenced in order to maintain a reasonable degree of consistency in the literature. When viewed in the perspective of dynamical models, a twisted warped gas layer can be understood as arising from orbiting gas which is in the process of settling to a preferred orientation in the nonspherical, gravitational potential well of the galaxy. Hence, detailed kinematical modeling of a specific galaxy disk can provide not only information regarding the orientation and structure of its warp but also information about the shape (whether oblate or prolate) of the dark halo in which the disk is embedded. By examining a large number of galaxies in a consistent manner, we have deduced some general characteristics of warped disks that have heretofore gone unnoticed. We have also identified uniqueness problems that can arise in this type of modeling procedure which can considerably cloud one's ability to completely decipher an individual disk's structure. For 14 out of 15 spiral galaxies modeled here, we have been able to determine the local kinematical structure of the warp. Gas layers do not appear to warp more than ˜40° out of the plane defined by the central disk of the galaxy, but they can twist through angles as large as ˜170

  16. Learning to throw on a rotating carousel: recalibration based on limb dynamics and projectile kinematics.

    PubMed

    Bruggeman, Hugo; Pick, Herbert L; Rieser, John J

    2005-05-01

    Skilled actions exhibit adjustment in calibration to bring about their goals. The sought-after calibrations change as a function of the environmental situation that stages the actions. In these experiments participants sat on one side of a rotating carousel and threw beanbags underhanded at a target fixed on the opposite side. Logically, aimed throwing in this situation involves adjustment to fit changes in limb dynamics (originating from Coriolis forces) and changes in perceived projectile kinematics (originating from the tangential velocity of thrower and target). We studied whether such adjustment involved one or multiple components of recalibration. An initial experiment showed that exposure to rotation while throwing beanbags produced a robust recalibration in the direction of underhanded throws as manifest in throwing at stationary targets from a stationary position. Following some initial decay this recalibration persisted and approached an asymptote. Subsequent experiments suggested two independent components of recalibration. One is based on limb dynamics and accounts for the initial decay. The other is based on the perceived projectile kinematics and accounts for the stable change in throwing direction. These results raised the question of how multiple components of recalibration of an action are related. We propose that movement components are independent and calibrated separately at different levels in the organization of an action.

  17. The Impact of Fatigue on the Kinematics of Collegiate Baseball Pitchers

    PubMed Central

    Grantham, W. Jeffrey; Byram, Ian R.; Meadows, Molly C.; Ahmad, Christopher S.

    2014-01-01

    Background: Many factors are believed to contribute to throwing injuries in baseball pitchers, in particular overuse and poor throwing mechanics. The impact of fatigue on pitching biomechanics in live-game situations is not well understood. Hypothesis: Pitchers will demonstrate significant deviation in their pitching motions with increasing levels of fatigue. Study Design: Descriptive laboratory study. Methods: Eleven National Collegiate Athletic Association (NCAA) Division I collegiate baseball pitchers were filmed in multiple live-game situations throughout a single season using 2 orthogonal high-speed cameras at 120 Hz. The first fastball of each inning and, when available, the fastball subsequent to the 15th and 30th pitch of each inning were recorded and analyzed for 26 kinematic parameters. Pitch count and velocity were recorded. Kinematic differences were assessed for association with pitch count and subjective fatigue measures over the course of each inning and game through the season. Results: Twenty-six games were recorded. Pitchers had a mean of 97.2 ± 16.1 pitches per start and 1079 ± 251 pitches per collegiate season. Increased hip lean at hand separation, elbow height at foot contact, and hip flexion and shoulder tilt at maximum external rotation were seen in innings lasting longer than 15 pitches. Maximum external rotation of the shoulder and elbow height at foot contact decreased over the course of a game. Hip lean at hand separation and elbow height at foot contact increased over the course of the season. Season pitch count was weakly correlated with increased shoulder external rotation and shoulder alignment at maximum external rotation and with shoulder abduction at ball release. Elbow flexion decreased with greater season pitch counts. Conclusion: Hip lean, elbow height, and shoulder external rotation were the most sensitive kinematic parameters to inning, game, and season fatigue. Pitch count and fatigue have a significant impact on live

  18. Knee Proprioception and Strength and Landing Kinematics During a Single-Leg Stop-Jump Task

    PubMed Central

    Nagai, Takashi; Sell, Timothy C; House, Anthony J; Abt, John P; Lephart, Scott M

    2013-01-01

    Context The importance of the sensorimotor system in maintaining a stable knee joint has been recognized. As individual entities, knee-joint proprioception, landing kinematics, and knee muscles play important roles in functional joint stability. Preventing knee injuries during dynamic tasks requires accurate proprioceptive information and adequate muscular strength. Few investigators have evaluated the relationship between knee proprioception and strength and landing kinematics. Objective To examine the relationship between knee proprioception and strength and landing kinematics. Design Cross-sectional study. Setting University research laboratory. Patients or Other Participants Fifty physically active men (age = 26.4 ± 5.8 years, height = 176.5 ± 8.0 cm, mass = 79.8 ± 16.6 kg). Intervention(s) Three tests were performed. Knee conscious proprioception was evaluated via threshold to detect passive motion (TTDPM). Knee strength was evaluated with a dynamometer. A 3-dimensional biomechanical analysis of a single-legged stop-jump task was used to calculate initial contact (IC) knee-flexion angle and knee-flexion excursion. Main Outcome Measure(s) The TTDPM toward knee flexion and extension, peak knee flexion and extension torque, and IC knee-flexion angle and knee flexion excursion. Linear correlation and stepwise multiple linear regression analyses were used to evaluate the relationships of both proprioception and strength against landing kinematics. The α level was set a priori at .05. Results Enhanced TTDPM and greater knee strength were positively correlated with greater IC knee-flexion angle (r range = 0.281–0.479, P range = .001–.048). The regression analysis revealed that 27.4% of the variance in IC knee-flexion angle could be accounted for by knee-flexion peak torque and TTDPM toward flexion (P = .001). Conclusions The current research highlighted the relationship between knee proprioception and strength and landing kinematics. Individuals with enhanced

  19. Image Edge Extraction via Fuzzy Reasoning

    NASA Technical Reports Server (NTRS)

    Dominquez, Jesus A. (Inventor); Klinko, Steve (Inventor)

    2008-01-01

    A computer-based technique for detecting edges in gray level digital images employs fuzzy reasoning to analyze whether each pixel in an image is likely on an edge. The image is analyzed on a pixel-by-pixel basis by analyzing gradient levels of pixels in a square window surrounding the pixel being analyzed. An edge path passing through the pixel having the greatest intensity gradient is used as input to a fuzzy membership function, which employs fuzzy singletons and inference rules to assigns a new gray level value to the pixel that is related to the pixel's edginess degree.

  20. Electrostatic analysis of the tokamak edge plasma

    SciTech Connect

    Motley, R.W.

    1981-07-01

    The intrusion of an equipotential poloidal limiter into the edge plasma of a circular tokamak discharge distorts the axisymmetry in two ways: (1) it (partially) shorts out the top-to-bottom Pfirsch-Schlueter driving potentials, and (2) it creates zones of back current flow into the limiter. The resulting boundary mismatch between the outer layers and the inner axisymmetric Pfirsch-Schlueter layer provides free energy to drive the edge plasma unstable. Special limiters are proposed to symmetrize the edge plasma and thereby reduce the electrical and MHD activity in the boundary layer.

  1. An edge preserving differential image coding scheme

    NASA Technical Reports Server (NTRS)

    Rost, Martin C.; Sayood, Khalid

    1992-01-01

    Differential encoding techniques are fast and easy to implement. However, a major problem with the use of differential encoding for images is the rapid edge degradation encountered when using such systems. This makes differential encoding techniques of limited utility, especially when coding medical or scientific images, where edge preservation is of utmost importance. A simple, easy to implement differential image coding system with excellent edge preservation properties is presented. The coding system can be used over variable rate channels, which makes it especially attractive for use in the packet network environment.

  2. An optimal scale for edge detection

    NASA Astrophysics Data System (ADS)

    Geiger, Davi; Poggio, Tomaso

    1988-09-01

    Many problems in early vision are ill posed. Edge detection is a typical example. This paper applies regularization techniques to the problem of edge detection. The authors derive an optimal filter for edge detection with a size controlled by the regularization parameter lambda and compare it to the Gaussian filter. A formula relating the signal-to-noise ratio to the parameter lambda is derived from regularization analysis for the case of small values of lambda. Also discussed is the method of Generalized Cross Validation for obtaining the optimal filter scale. Finally, the authors use their framework to explain two perceptual phenomena: coarsely quantized images becoming recognizable by either blurring or adding noise.

  3. Cavitation on hydrofoils with sinusoidal leading edge

    NASA Astrophysics Data System (ADS)

    Johari, H.

    2015-12-01

    Cavitation characteristics of hydrofoils with sinusoidal leading edge were examined experimentally at a Reynolds number of 7.2 × 105. The hydrofoils had an underlying NACA 634-021 profile and an aspect ratio of 4.3. The sinusoidal leading edge geometries included three amplitudes of 2.5%, 5%, and 12% and two wavelengths of 25% and 50% of the mean chord length. Results revealed that cavitation on the leading edge-modified hydrofoils existed in pockets behind the troughs whereas the baseline hydrofoil produced cavitation along its entire span. Moreover, cavitation on the modified hydrofoils appeared at consistently lower angles of attack than on the baseline hydrofoil.

  4. Edge current in a small chiral superconductor

    NASA Astrophysics Data System (ADS)

    Suzuki, Shu-Ichiro; Asano, Yasuhiro

    2016-10-01

    We discuss a theoretical description of the edge current in a chiral superconductor. On the basis of the quasiclassical Green function formalism, we derive a useful expression of the chiral edge current which enable us to understand how Cooper pairs contribute to the electric current. We will show that the chiral edge current is carried by the combinations of two Cooper pairs belonging to different pairing symmetries. One Cooper pair belongs to the usual even-frequency pairing symmetry class. However, the other belongs to the odd-frequency symmetry class.

  5. Ab initio x-ray absorption near-edge structure study of Ti K-edge in rutile.

    PubMed

    Chaboy, J; Nakajima, N; Tezuka, Y

    2007-07-04

    This work reports a theoretical x-ray absorption near-edge structure (XANES) spectroscopy study at the Ti K-edge in TiO(2) rutile. We present detailed ab initio computations of the Ti K-edge XANES spectrum performed within the multiple-scattering framework. An extensive discussion is presented concerning the size of the cluster needed to reproduce the experimental spectrum, especially regarding the split main absorption line. In addition, the role of the exchange and correlation potential (ECP) in reproducing all the experimental XANES features is discussed. The best agreement between experimental data and computations is obtained by using real ECP potentials, i.e. the energy-dependent Dirac-Hara exchange potential, or by using only the real part of the energy-dependent Hedin-Lundqvist complex potential, together with an additional imaginary constant to account for the core-hole lifetime and the experimental resolution. The addition of the imaginary part of the HL potential worsens the agreement between the experimental and calculated spectra, indicating the failure of the complex part of the Hedin-Lundqvist ECP in accounting for the electron damping in these systems.

  6. The complexity of South China Sea kinematics

    NASA Astrophysics Data System (ADS)

    Sibuet, Jean-Claude; Gao, Jinyao; Zhao, Minghui; Wu, Jonny; Ding, Weiwei; Yeh, Yi-Ching; Lee, Chao-Shing

    2016-04-01

    Magnetic modeling shows that the age of the youngest South China Sea (SCS) oceanic crust is controversial (e.g. 15.5 Ma, Briais et al., JGR 1993 and 20.5 Ma, Barckhausen et al., MPG 2014). Close to the rift axis of the East sub-basin, Ar-Ar age dating of oceanic crustal rocks collected during IODP Leg 349 gives ages of 15 and 15.2 +/- 0.2 Ma (Koppers, Fall AGU meeting, 2014), which seems to favor the 15.5 Ma age given by Briais et al. modeling. However, basaltic samples might belong to a sill and not to the typical oceanic crust. As post-spreading magmatic activity (~8-13 Ma) largely masks the spreading fabric, in particular near the previously identified E-W portion of the extinct ridge axis of the East sub-basin, the published locations of the axial magnetic anomaly and spreading rates are incorrect. The compilation of available swath bathymetric data shows that if post-spreading volcanics hide the seafloor spreading magnetic fabric mostly along and near the extinct spreading axis, the whole SCS is globally characterized by rift directions following three directions: N055°in the youngest portion of the SCS, N065° and N085° in the oldest portions of the SCS (Sibuet et al., Tectonophysics 2016) suggesting the extinct ridge axis is N055° trending instead of E-W. We present an updated version of the whole SCS structural sketch based on previously published swath bathymetric trends and new detailed magnetic lineations trends compiled from an extremely dense set of magnetic data. The new structural sketch shows: - The distribution of conjugate kinematic domains, - The early opening of the NW and East sub-basins, before a jump of the rift axis, - A second ridge jump in the East basin, - The different expressions of the post-spreading magmatism in the East and SW sub-basins. In the East sub-basin, crustal magmatic intrusions led to the formation of extrusive basalts associated with the presence of numerous volcanoes (Wang et al., Geological Journal 2016). In the SW

  7. Multiple Sclerosis

    MedlinePlus

    Multiple sclerosis Overview By Mayo Clinic Staff Multiple sclerosis (MS) is a potentially disabling disease of the brain and spinal cord (central nervous system). In MS, the immune system attacks the protective ...

  8. Multiple Sclerosis

    MedlinePlus

    Multiple sclerosis (MS) is a nervous system disease that affects your brain and spinal cord. It damages the ... attacks healthy cells in your body by mistake. Multiple sclerosis affects women more than men. It often begins ...

  9. Multiple myeloma

    MedlinePlus

    Plasma cell dyscrasia; Plasma cell myeloma; Malignant plasmacytoma; Plasmacytoma of bone; Myeloma - multiple ... Multiple myeloma most commonly causes: Low red blood cell count ( anemia ), which can lead to fatigue and ...

  10. On a combined adaptive tetrahedral tracing and edge diffraction model

    NASA Astrophysics Data System (ADS)

    Hart, Carl R.

    A major challenge in architectural acoustics is the unification of diffraction models and geometric acoustics. For example, geometric acoustics is insufficient to quantify the scattering characteristics of acoustic diffusors. Typically the time-independent boundary element method (BEM) is the method of choice. In contrast, time-domain computations are of interest for characterizing both the spatial and temporal scattering characteristics of acoustic diffusors. Hence, a method is sought that predicts acoustic scattering in the time-domain. A prediction method, which combines an advanced image source method and an edge diffraction model, is investigated for the prediction of time-domain scattering. Adaptive tetrahedral tracing is an advanced image source method that generates image sources through an adaptive process. Propagating tetrahedral beams adapt to ensonified geometry mapping the geometric sound field in space and along boundaries. The edge diffraction model interfaces with the adaptive tetrahedral tracing process by the transfer of edge geometry and visibility information. Scattering is quantified as the contribution of secondary sources along a single or multiple interacting edges. Accounting for a finite number of diffraction permutations approximates the scattered sound field. Superposition of the geometric and scattered sound fields results in a synthesized impulse response between a source and a receiver. Evaluation of the prediction technique involves numerical verification and numerical validation. Numerical verification is based upon a comparison with analytic and numerical (BEM) solutions for scattering geometries. Good agreement is shown for the selected scattering geometries. Numerical validation is based upon experimentally determined scattered impulse responses of acoustic diffusors. Experimental data suggests that the predictive model is appropriate for high-frequency predictions. For the experimental determination of the scattered impulse

  11. Effects of Timber Harvests and Silvicultural Edges on Terrestrial Salamanders

    PubMed Central

    MacNeil, Jami E.; Williams, Rod N.

    2014-01-01

    Balancing timber production and conservation in forest management requires an understanding of how timber harvests affect wildlife species. Terrestrial salamanders are useful indicators of mature forest ecosystem health due to their importance to ecosystem processes and sensitivity to environmental change. However, the effects of timber harvests on salamanders, though often researched, are still not well understood. To further this understanding, we used artificial cover objects to monitor the relative abundance of terrestrial salamanders for two seasons (fall and spring) pre-harvest and five seasons post-harvest in six forest management treatments, and for three seasons post-harvest across the edge gradients of six recent clearcuts. In total, we recorded 19,048 encounters representing nine species of salamanders. We observed declines in mean encounters of eastern red-backed salamanders (Plethodon cinereus) and northern slimy salamanders (P. glutinosus) from pre- to post-harvest in group selection cuts and in clearcuts. However, we found no evidence of salamander declines at shelterwoods and forested sites adjacent to harvests. Edge effects induced by recent clearcuts influenced salamanders for approximately 20 m into the forest, but edge influence varied by slope orientation. Temperature, soil moisture, and canopy cover were all correlated with salamander counts. Our results suggest silvicultural techniques that remove the forest canopy negatively affect salamander relative abundance on the local scale during the years immediately following harvest, and that the depth of edge influence of clearcuts on terrestrial salamanders is relatively shallow (<20 m). Small harvests (<4 ha) and techniques that leave the forest canopy intact may be compatible with maintaining terrestrial salamander populations across a forested landscape. Our results demonstrate the importance of examining species-specific responses and monitoring salamanders across multiple seasons and years

  12. Edge determination for polycrystalline silicon lines on gate oxide

    NASA Astrophysics Data System (ADS)

    Villarrubia, John S.; Vladar, Andras E.; Lowney, Jeremiah R.; Postek, Michael T., Jr.

    2001-08-01

    In a scanning electron microscope (SEM) top-down secondary electron image, areas within a few tens of nanometers of the line edges are characteristically brighter than the rest of the image. In general, the shape of the secondary electron signal within such edge regions depends upon the energy and spatial distribution of the electron beam and the sample composition, and it is sensitive to small variations in sample geometry. Assigning edge shape and position is done by finding a model sample that is calculated, on the basis of a mathematical model of the instrument-sample interaction, to produce an image equal to the one actually observed. Edge locations, and consequently line widths, are then assigned based upon this model sample. In previous years we have applied this strategy to lines with geometry constrained by preferential etching of single crystal silicon. With this study we test the procedure on polycrystalline silicon lines. Polycrystalline silicon lines fabricated according to usual industrial processes represent a commercially interesting albeit technically more challenging application of this method. With the sample geometry less constrained a priori, a larger set of possible sample geometries must be modeled and tested for a match to the observed line scan, and the possibility of encountering multiple acceptable matches is increased. For this study we have implemented a data analysis procedure that matches measured image line scans to a precomputed library of sample shapes and their corresponding line scans. Linewidth test patterns containing both isolated and dense lines separated form the underlying silicon substrate by a thin gate oxide have been fabricated. Line scans from test pattern images have been fitted to the library of modeled shapes.

  13. Effects of timber harvests and silvicultural edges on terrestrial salamanders.

    PubMed

    MacNeil, Jami E; Williams, Rod N

    2014-01-01

    Balancing timber production and conservation in forest management requires an understanding of how timber harvests affect wildlife species. Terrestrial salamanders are useful indicators of mature forest ecosystem health due to their importance to ecosystem processes and sensitivity to environmental change. However, the effects of timber harvests on salamanders, though often researched, are still not well understood. To further this understanding, we used artificial cover objects to monitor the relative abundance of terrestrial salamanders for two seasons (fall and spring) pre-harvest and five seasons post-harvest in six forest management treatments, and for three seasons post-harvest across the edge gradients of six recent clearcuts. In total, we recorded 19,048 encounters representing nine species of salamanders. We observed declines in mean encounters of eastern red-backed salamanders (Plethodon cinereus) and northern slimy salamanders (P. glutinosus) from pre- to post-harvest in group selection cuts and in clearcuts. However, we found no evidence of salamander declines at shelterwoods and forested sites adjacent to harvests. Edge effects induced by recent clearcuts influenced salamanders for approximately 20 m into the forest, but edge influence varied by slope orientation. Temperature, soil moisture, and canopy cover were all correlated with salamander counts. Our results suggest silvicultural techniques that remove the forest canopy negatively affect salamander relative abundance on the local scale during the years immediately following harvest, and that the depth of edge influence of clearcuts on terrestrial salamanders is relatively shallow (<20 m). Small harvests (<4 ha) and techniques that leave the forest canopy intact may be compatible with maintaining terrestrial salamander populations across a forested landscape. Our results demonstrate the importance of examining species-specific responses and monitoring salamanders across multiple seasons and years

  14. Fundamental Principles of Proper Space Kinematics

    NASA Astrophysics Data System (ADS)

    Wade, Sean

    It is desirable to understand the movement of both matter and energy in the universe based upon fundamental principles of space and time. Time dilation and length contraction are features of Special Relativity derived from the observed constancy of the speed of light. Quantum Mechanics asserts that motion in the universe is probabilistic and not deterministic. While the practicality of these dissimilar theories is well established through widespread application inconsistencies in their marriage persist, marring their utility, and preventing their full expression. After identifying an error in perspective the current theories are tested by modifying logical assumptions to eliminate paradoxical contradictions. Analysis of simultaneous frames of reference leads to a new formulation of space and time that predicts the motion of both kinds of particles. Proper Space is a real, three-dimensional space clocked by proper time that is undergoing a densification at the rate of c. Coordinate transformations to a familiar object space and a mathematical stationary space clarify the counterintuitive aspects of Special Relativity. These symmetries demonstrate that within the local universe stationary observers are a forbidden frame of reference; all is in motion. In lieu of Quantum Mechanics and Uncertainty the use of the imaginary number i is restricted for application to the labeling of mass as either material or immaterial. This material phase difference accounts for both the perceived constant velocity of light and its apparent statistical nature. The application of Proper Space Kinematics will advance more accurate representations of microscopic, oscopic, and cosmological processes and serve as a foundation for further study and reflection thereafter leading to greater insight.

  15. Stellar kinematics of elliptical galaxies in pairs

    NASA Technical Reports Server (NTRS)

    Madejsky, Rainer; Bender, Ralf

    1990-01-01

    In both galaxy pairs Arp 166 and 3C 278 the authors find radially increasing velocity dispersions indicating a perturbed, non-equilibrium state of the galaxies after the tidal interaction. In all galaxies, the increase is most pronounced in the regions which correspond to the centers of the outer isophotes. The authors suggest a scenario in which the galaxies are strongly decelerated on their orbits during the encounter. The deceleration depends on the radial position in the perturbed galaxy and vanishes in the center of the perturbed galaxy (Spitzer, 1958). In addition, the crossing time of the stars near the center is very short, implying that the tidal perturbations can be averaged over several orbital periods (e.g., Binney and Tremaine, 1987). In consequence, the central parts are not affected by the tidal interaction while the outer parts are strongly decelerated. This leads to a displacement of the central parts of the galaxies with respect to their envelopes in an anti-symmetrical way for the two components of each galaxy pair. The motions of the central parts subsequently are opposed by dynamical friction with the surrounding envelopes. Due to dynamical friction, the density of the stars increases in the wakes of the moving central parts (Mulder, 1983). The overdensity of stars in the wakes of the moving central parts efficiently decelerates the motions of the central parts. The reaction of the stars in the overdensity regions leads to an increase of the velocity dispersion mainly along the orbits of the moving central parts. The presented observations, especially the asymmetrical luminosity profiles and the radially increasing velocity dispersions support consistently the above scenario of tidal interaction between galaxies. Further spectroscopic observations are necessary in order to investigate the degree of anisotropy in the kinematically perturbed regions.

  16. Global and regional kinematics with GPS

    NASA Technical Reports Server (NTRS)

    King, Robert W.

    1994-01-01

    The inherent precision of the doubly differenced phase measurement and the low cost of instrumentation made GPS the space geodetic technique of choice for regional surveys as soon as the constellation reached acceptable geometry in the area of interest: 1985 in western North America, the early 1990's in most of the world. Instrument and site-related errors for horizontal positioning are usually less than 3 mm, so that the dominant source of error is uncertainty in the reference frame defined by the satellites orbits and the tracking stations used to determine them. Prior to about 1992, when the tracking network for most experiments was globally sparse, the number of fiducial sites or the level at which they could be tied to an SLR or VLBI reference frame usually, set the accuracy limit. Recently, with a global network of over 30 stations, the limit is set more often by deficiencies in models for non-gravitational forces acting on the satellites. For regional networks in the northern hemisphere, reference frame errors are currently about 3 parts per billion (ppb) in horizontal position, allowing centimeter-level accuracies over intercontinental distances and less than 1 mm for a 100 km baseline. The accuracy of GPS measurements for monitoring height variations is generally 2-3 times worse than for horizontal motions. As for VLBI, the primary source of error is unmodeled fluctuations in atmospheric water vapor, but both reference frame uncertainties and some instrument errors are more serious for vertical than horizontal measurements. Under good conditions, daily repeatabilities at the level of 10 mm rms were achieved. This paper will summarize the current accuracy of GPS measurements and their implication for the use of SLR to study regional kinematics.

  17. Growth Kinematics of Opening-Mode Fractures

    NASA Astrophysics Data System (ADS)

    Eichhubl, P.; Alzayer, Y.; Laubach, S.; Fall, A.

    2014-12-01

    Fracture aperture is a primary control on flow in fractured reservoirs of low matrix permeability including unconventional oil and gas reservoirs and most geothermal systems. Guided by principles of linear elastic fracture mechanics, fracture aperture is generally assumed to be a linear function of fracture length and elastic material properties. Natural opening-mode fractures with significant preserved aperture are observed in core and outcrop indicative of fracture opening strain accommodated by permanent solution-precipitation creep. Fracture opening may thus be decoupled from length growth if the material effectively weakens after initial elastic fracture growth by either non-elastic deformation processes or changes in elastic properties. To investigate the kinematics of fracture length and aperture growth, we reconstructed the opening history of three opening-mode fractures that are bridged by crack-seal quartz cement in Travis Peak Sandstone of the SFOT-1 well, East Texas. Similar crack-seal cement bridges had been interpreted to form by repeated incremental fracture opening and subsequent precipitation of quartz cement. We imaged crack-seal cement textures for bridges sampled at varying distance from the tips using scanning electron microscope cathodoluminescence, and determined the number and thickness of crack-seal cement increments as a function of position along the fracture length and height. Observed trends in increment number and thickness are consistent with an initial stage of fast fracture propagation relative to aperture growth, followed by a stage of slow propagation and pronounced aperture growth. Consistent with fluid inclusion observations indicative of fracture opening and propagation occurring over 30-40 m.y., we interpret the second phase of pronounced aperture growth to result from fracture opening strain accommodated by solution-precipitation creep and concurrent slow, possibly subcritical, fracture propagation. Similar deformation

  18. Morpho-kinematic modeling of planetary nebulae

    NASA Astrophysics Data System (ADS)

    Chan, Tsz-Pan (Henry)

    2009-11-01

    The Planetary Nebulae (PNe) are the transition phase between asymptotic giant branch (AGB) star and white dwarfs for stars with masses between 1 and 8 M⊙. They were originally thought to be well-studied and can be explained with simple models. With the advance of imaging technology especially on Space Telescope (HST), the shapes of PNe have been found to be much more complex than we assumed to be. We aimed to investigate on the basic but mysterious intrinsic three-dimensional structures using the newly developed modeling software. Astronomers usually use the morphological classification on group and classify different properties of PNe. Over the past century many attempts have been made for this classification to seek for explaining and understanding the threedimensional structure that is responsible for the observed images. There have been two beliefs in explaining the variety of shapes of PNe and among them the most amazing one is that the morphologies can be accounted by different orientations of a single structure (Khromov & Kohoutek, 1968). Motivated by the study of Ring Nebula on its intrinsic structure, we investigated the possibility that different types of morphology in PNe can be explained by a single model. We used the newly developed modeling code SHAPE (Steffen et al., 2006), which cooperates the use of spatial information as well as its kinematics, and aimed to quantitatively investigate the basic structure inside PNe. We investigated two classical nebulae: NGC 2346 and NGC 2440. We proposed a simple but adequate model for these nebulae. Stimulated optical images and the p-v arrays were derived by the modeling code SHAPE to make comparison with the observed data to seek for the correctness of the model. Hubble velocity field and inverse square law density distribution were assumed throughout the modeling process. This model provides insights in seeking further adequate intrinsic structure of PNe.

  19. Chemical abundances and kinematics of barium stars

    NASA Astrophysics Data System (ADS)

    de Castro, D. B.; Pereira, C. B.; Roig, F.; Jilinski, E.; Drake, N. A.; Chavero, C.; Sales Silva, J. V.

    2016-07-01

    In this paper, we present an homogeneous analysis of photospheric abundances based on high-resolution spectroscopy of a sample of 182 barium stars and candidates. We determined atmospheric parameters, spectroscopic distances, stellar masses, ages, luminosities and scaleheight, radial velocities, abundances of the Na, Al, α-elements, iron-peak elements, and s-process elements Y, Zr, La, Ce, and Nd. We employed the local thermodynamic equilibrium model atmospheres of Kurucz and the spectral analysis code MOOG. We found that the metallicities, the temperatures and the surface gravities for barium stars cannot be represented by a single Gaussian distribution. The abundances of α-elements and iron peak elements are similar to those of field giants with the same metallicity. Sodium presents some degree of enrichment in more evolved stars that could be attributed to the NeNa cycle. As expected, the barium stars show overabundance of the elements created by the s-process. By measuring the mean heavy-element abundance pattern as given by the ratio [s/Fe], we found that the barium stars present several degrees of enrichment. We also obtained the [hs/ls] ratio by measuring the photospheric abundances of the Ba-peak and the Zr-peak elements. Our results indicated that the [s/Fe] and the [hs/ls] ratios are strongly anticorrelated with the metallicity. Our kinematical analysis showed that 90 per cent of the barium stars belong to the thin disc population. Based on their luminosities, none of the barium stars are luminous enough to be an asymptotic giant branch star, nor to become self-enriched in the s-process elements. Finally, we determined that the barium stars also follow an age-metallicity relation.

  20. Estimating the Kinematic Viscosity of Petroleum Fractions

    NASA Astrophysics Data System (ADS)

    AlMulla, Hessa A.; Albahri, Tareq A.

    2017-04-01

    Kinematic viscosity correlation has been developed for liquid petroleum fractions at 37.78°C and 98.89°C (100 and 210°F) standard temperatures using a large variety of experimental data. The only required inputs are the specific gravity and the average boiling point temperature. The accuracy of the correlation was compared with several other correlations available in the literature. The proposed correlations proved to be more accurate in predicting the viscosity at 37.78°C and 98.89°C with average absolute deviations of 0.39 and 0.72 mm2/s, respectively. Another objective was to develop a relation for the variation of viscosity with temperature to predict the viscosity of petroleum fraction at a certain temperature from the knowledge of the viscosity for the same liquid at two other temperatures. The newly developed correlation represents a wide array of temperatures from 20°C to 150°C and viscosities from 0.14 mm2/s to 343.64 mm2/s. The results have been validated with experimental data consisting of 9558 data points, yielding an overall deviation of 0.248 mm2/s and R2 of 0.998. In addition, new formulas were developed to interconvert the viscosity of petroleum fractions from one unit of measure to another based on finding the best fit for a set of experimental data from the literature with R2 as high as 1.0 for many cases. Detailed analysis showed good agreement between the predicted values and the experimental data.