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Sample records for vh-mode evolution edge

  1. Beta limits in H-modes and VH-modes in JET

    Energy Technology Data Exchange (ETDEWEB)

    Smeulders, P.; Hender, T.C.; Huysmans, G.; Marcus, F.; Ali-Arshad, S.; Alper, B.; Balet, B.; Bures, M.; Deliyanakis, N.; Esch, H. de; Fshpool, G.; Jarvis, O.N.; Jones, T.T.C.; Ketner, W.; Koenig, R.; Lawson, K.; Lomas, P.; O`Brien, D.; Sadler, G.; Stok, D.; Stubberfield, P.; Thomas, P.; Thomen, K.; Wesson, J. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Nave, M.F. [Universidade Tecnica, Lisbon (Portugal). Inst. Superior Tecnico

    1994-07-01

    In Hot-ion H- and VH-modes, the highest achieved beta was about 10% below the Troyon value in the best case of discharge 26087. The operational space of the high beta discharges obtained before March 1992 has been explored as function of the parameters H{sub ITER89P}, {beta}{sub n}, q{sub 95}, I{sub p}. Also, a limiting envelope on the fusion reactivity as a function of the average plasma pressure and beta has been observed with R{sub DD} related to {beta}{sub {phi}}{sup 2}.B{sub {phi}}{sup 4}. MHD stability analysis shows that the JET VH modes at the edge are in the second region for ballooning mode stability. The dependence of ballooning stability and the n=1 external kink on the edge current density is analyzed. (authors). 6 figs., 6 refs.

  2. Confinement and stability of VH-mode discharges in the DIII-D tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, T.S.; Osborne, T.H.; Burrell, K.H.; Carlstrom, T.N.; Chan, V.S.; Chu, M.S.; DeBoo, J.C.; Doyle, E.J.; Greenfield, C.M.; Groebner, R.J.; Hsieh, C.L.; Jackson, G.L.; James, R.; Lao, L.L.; Lazarus, E.A.; Lippman, S.I.; Petrie, T.W.; Rettig, C.L.; St. John, H.; Schissel, D.P.; Stambaugh, R.D.; Strait, E.J.; Turnbull, A.D.; West, W.P.; Winter, J.; Wroblewski, D.

    1992-10-01

    A regime of very high confinement (VH-mode) has been observed in neutral beam-heated deuterium discharges in the DIII-D tokamak with thermal energy confinement times up to [approx]3.6 times that predicted by the ITER-89P L-mode scaling and 2 times that predicted by ELM-free H-mode thermal confinement scalings. This high confinement has led to increased plasma performance, n[sub D] (0)T[sub i](0)[tau][sub E] = 2 [times] 10[sup 20] m[sup [minus]3] keV sec with I[sub p] = 1.6 MA, B[sub T] = 2.1 T, Z[sub eff] [le] 2. Detailed transport analysis shows a correspondence between the large decrease in thermal diffusivity in the region 0.75 [le] [rho] [le] 0.9 and the development of a strong shear in the radial electric field in the same region. This suggests that stabilization of turbulence by sheared E [times] B flow is responsible for the improved confinement in VH-mode. A substantial fraction of the edge plasma entering the second regime of stability may also contribute to the increase in confinement. The duration of the VH-mode phase has been lengthened by feedback controlling the input power to limit plasma beta.

  3. Confinement and stability of VH-mode discharges in the DIII-D tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, T.S.; Osborne, T.H.; Burrell, K.H.; Carlstrom, T.N.; Chan, V.S.; Chu, M.S.; DeBoo, J.C.; Doyle, E.J.; Greenfield, C.M.; Groebner, R.J.; Hsieh, C.L.; Jackson, G.L.; James, R.; Lao, L.L.; Lazarus, E.A.; Lippman, S.I.; Petrie, T.W.; Rettig, C.L.; St. John, H.; Schissel, D.P.; Stambaugh, R.D.; Strait, E.J.; Turnbull, A.D.; West, W.P.; Winter, J.; Wroblewski, D.

    1992-10-01

    A regime of very high confinement (VH-mode) has been observed in neutral beam-heated deuterium discharges in the DIII-D tokamak with thermal energy confinement times up to {approx}3.6 times that predicted by the ITER-89P L-mode scaling and 2 times that predicted by ELM-free H-mode thermal confinement scalings. This high confinement has led to increased plasma performance, n{sub D} (0)T{sub i}(0){tau}{sub E} = 2 {times} 10{sup 20} m{sup {minus}3} keV sec with I{sub p} = 1.6 MA, B{sub T} = 2.1 T, Z{sub eff} {le} 2. Detailed transport analysis shows a correspondence between the large decrease in thermal diffusivity in the region 0.75 {le} {rho} {le} 0.9 and the development of a strong shear in the radial electric field in the same region. This suggests that stabilization of turbulence by sheared E {times} B flow is responsible for the improved confinement in VH-mode. A substantial fraction of the edge plasma entering the second regime of stability may also contribute to the increase in confinement. The duration of the VH-mode phase has been lengthened by feedback controlling the input power to limit plasma beta.

  4. VH mode accessibility and global H-mode properties in previous and present JET configurations

    Energy Technology Data Exchange (ETDEWEB)

    Jones, T.T.C.; Ali-Arshad, S.; Bures, M.; Christiansen, J.P.; Esch, H.P.L. de; Fishpool, G.; Jarvis, O.N.; Koenig, R.; Lawson, K.D.; Lomas, P.J.; Marcus, F.B.; Sartori, R.; Schunke, B.; Smeulders, P.; Stork, D.; Taroni, A.; Thomas, P.R.; Thomsen, K. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

    1994-07-01

    In JET VH modes, there is a distinct confinement transition following the cessation of ELMs, observed in a wide variety of tokamak operating conditions, using both NBI and ICRF heating methods. Important factors which influence VH mode accessibility such as magnetic configuration and vessel conditions have been identified. The new JET pumped divertor configuration has much improved plasma shaping control and power and particle exhaust capability and should permit exploitation of plasmas with VH confinement properties over an even wider range of operating regimes, particularly at high plasma current; first H-modes have been obtained in the 1994 JET operating period and initial results are reported. (authors). 7 refs., 6 figs.

  5. The stochastic edge in adaptive evolution

    OpenAIRE

    Brunet, Éric; Rouzine, Igor M.; Wilke, Claus O

    2007-01-01

    In a recent article, Desai and Fisher (2007) proposed that the speed of adaptation in an asexual population is determined by the dynamics of the stochastic edge of the population, that is, by the emergence and subsequent establishment of rare mutants that exceed the fitness of all sequences currently present in the population. Desai and Fisher perform an elaborate stochastic calculation of the mean time $\\tau$ until a new class of mutants has been established, and interpret $1/\\tau$ as the sp...

  6. The edge of neutral evolution in social dilemmas

    Energy Technology Data Exchange (ETDEWEB)

    Cremer, Jonas; Frey, Erwin [Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilians-Universitaet Muenchen, Theresienstrasse 37, D-80333 Muenchen (Germany); Reichenbach, Tobias [Howard Hughes Medical Institute and Laboratory of Sensory Neuroscience, Rockefeller University, 1230 York Avenue, New York, NY 10065 (United States)], E-mail: jonas.cremer@physik.uni-muenchen.de

    2009-09-15

    The functioning of animal as well as human societies fundamentally relies on cooperation. Yet, defection is often favorable for the selfish individual, and social dilemmas arise. Selection by individuals' fitness, usually the basic driving force of evolution, quickly eliminates cooperators. However, evolution is also governed by fluctuations that can be of greater importance than fitness differences, and can render evolution effectively neutral. Here, we investigate the effects of selection versus fluctuations in social dilemmas. By studying the mean extinction times of cooperators and defectors, a variable sensitive to fluctuations, we are able to identify and quantify an emerging 'edge of neutral evolution' that delineates regimes of neutral and Darwinian evolution. Our results reveal that cooperation is significantly maintained in the neutral regimes. In contrast, the classical predictions of evolutionary game theory, where defectors beat cooperators, are recovered in the Darwinian regimes. Our studies demonstrate that fluctuations can provide a surprisingly simple way to partly resolve social dilemmas. Our methods are generally applicable to estimate the role of random drift in evolutionary dynamics.

  7. Evolution to the Edge of Chaos in Imitation Game

    CERN Document Server

    Kaneko, K; Kaneko, Kunihiko; Suzuki, Junji

    1993-01-01

    Motivated by the evolution of complex bird songs, an abstract imitation game is proposed to study the increase of dynamical complexity: Artificial "birds" display a "song" time series to each other, and those that imitate the other's song better win the game. With the introduction of population dynamics according to the score of the game and the mutation of parameters for the song dynamics, the dynamics is found to evolve towards the borderline between chaos and a periodic window, after punctuated equilibria. The importance of edge of chaos with topological chaos for complexity is stressed.

  8. The non-linear evolution of edge localized modes

    Energy Technology Data Exchange (ETDEWEB)

    Wenninger, Ronald

    2013-01-09

    Edge localized modes (ELMs) are instabilities in the edge of tokamak plasmas in the high confinement regime (H-mode). Without them the edge transport in ordinary H-mode plasmas is too low to establish a stationary situation. However in a future device large unmitigated ELMs are believed to cause divertor power flux densities far in excess of tolerable material limits. Hence the size of energy loss per ELM and the resulting ELM frequency must be controlled. To proceed in understanding how the ELM size is determined and how ELM mitigation methods work it is necessary to characterize the non-linear evolution of pedestal erosion. In order to achieve this experimental data is compared to the results of ELM simulations with the code JOREK (reduced MHD, non-linear) applying a specially developed synthetic magnetic diagnostic. The experimental data are acquired by several fast sampling diagnostics at the experiments ASDEX Upgrade and TCV at a large number of toroidal/poloidal positions. A central element of the presented work is the detailed characterization of dominant magnetic perturbations during ELMs. These footprints of the instability can be observed most intensely in close temporal vicinity to the onset of pedestal erosion. Dominant magnetic perturbations are caused by current perturbations located at or inside the last closed flux surface. In ASDEX Upgrade under certain conditions dominant magnetic perturbations like other H-mode edge instabilities display a similarity to solitons. Furthermore - as expected - they are often observed to be correlated to a perturbation of electron temperature. In TCV it is possible to characterize the evolution of the toroidal structure of dominant magnetic perturbations. Between growing above the level of background fluctuations and the maximum perturbation level for all time instance a similar toroidal structure is observed. This rigid mode-structure is an indication for non-linear coupling. Most frequently the dominant toroidal

  9. Damage Evolution in Complex-Phase and Dual-Phase Steels during Edge Stretching.

    Science.gov (United States)

    Pathak, Nikky; Butcher, Cliff; Worswick, Michael James; Bellhouse, Erika; Gao, Jeff

    2017-03-27

    The role of microstructural damage in controlling the edge stretchability of Complex-Phase (CP) and Dual-Phase (DP) steels was evaluated using hole tension experiments. The experiments considered a tensile specimen with a hole at the center of specimen that is either sheared (sheared edge condition) or drilled and then reamed (reamed edge condition). The damage mechanism and accumulation in the CP and DP steels were systematically characterized by interrupting the hole tension tests at different strain levels using scanning electron microscope (SEM) analysis and optical microscopy. Martensite cracking and decohesion of ferrite-martensite interfaces are the dominant nucleation mechanisms in the DP780. The primary source of void nucleation in the CP800 is nucleation at TiN particles, with secondary void formation at martensite/bainite interfaces near the failure strain. The rate of damage evolution is considerably higher for the sheared edge in contrast with the reamed edge since the shearing process alters the microstructure in the shear affected zone (SAZ) by introducing work-hardening and initial damage behind the sheared edge. The CP microstructures were shown to be less prone to shear-induced damage than the DP materials resulting in much higher sheared edge formability. Microstructural damage in the CP and DP steels was characterized to understand the interaction between microstructure, damage evolution and edge formability during edge stretching. An analytical model for void evolution and coalescence was developed and applied to predict the damage rate in these rather diverse microstructures.

  10. Damage Evolution in Complex-Phase and Dual-Phase Steels during Edge Stretching

    Directory of Open Access Journals (Sweden)

    Nikky Pathak

    2017-03-01

    Full Text Available The role of microstructural damage in controlling the edge stretchability of Complex-Phase (CP and Dual-Phase (DP steels was evaluated using hole tension experiments. The experiments considered a tensile specimen with a hole at the center of specimen that is either sheared (sheared edge condition or drilled and then reamed (reamed edge condition. The damage mechanism and accumulation in the CP and DP steels were systematically characterized by interrupting the hole tension tests at different strain levels using scanning electron microscope (SEM analysis and optical microscopy. Martensite cracking and decohesion of ferrite-martensite interfaces are the dominant nucleation mechanisms in the DP780. The primary source of void nucleation in the CP800 is nucleation at TiN particles, with secondary void formation at martensite/bainite interfaces near the failure strain. The rate of damage evolution is considerably higher for the sheared edge in contrast with the reamed edge since the shearing process alters the microstructure in the shear affected zone (SAZ by introducing work-hardening and initial damage behind the sheared edge. The CP microstructures were shown to be less prone to shear-induced damage than the DP materials resulting in much higher sheared edge formability. Microstructural damage in the CP and DP steels was characterized to understand the interaction between microstructure, damage evolution and edge formability during edge stretching. An analytical model for void evolution and coalescence was developed and applied to predict the damage rate in these rather diverse microstructures.

  11. Role of the Edge Properties in the Hydrogen Evolution Reaction on MoS2.

    Science.gov (United States)

    Lazar, Petr; Otyepka, Michal

    2017-04-06

    Molybdenum disulfide, in particular its edges, has attracted considerable attention as possible substitute for platinum catalysts in the hydrogen evolution reaction (HER). The complex nature of the reaction complicates its detailed experimental investigations, which are mostly indirect and sample dependent. Therefore, density functional theory calculations were employed to study how the properties of the MoS2 Mo-edge influence the thermodynamics of hydrogen adsorption onto the edge. The effect of the computational model (one-dimensional nanostripe), border symmetry imposed by its length, sulfur saturation of the edge, and dimensionality of the material are discussed. Hydrogen adsorption was found to depend critically on the coverage of extra sulfur at the Mo edge. The bare Mo-edge and fully sulfur-covered Mo-edge are catalytically inactive. The most favorable hydrogen binding towards HER was found for the Mo-edge covered by sulfur monomers. This edge provides hydrogen adsorption free energies positioned around -0.25 eV at up to 50 % hydrogen coverage, close to the experimental values of overpotential needed for the HER reaction. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Identifying Major Transitions in the Evolution of Lithic Cutting Edge Production Rates.

    Directory of Open Access Journals (Sweden)

    Antoine Muller

    Full Text Available The notion that the evolution of core reduction strategies involved increasing efficiency in cutting edge production is prevalent in narratives of hominin technological evolution. Yet a number of studies comparing two different knapping technologies have found no significant differences in edge production. Using digital analysis methods we present an investigation of raw material efficiency in eight core technologies broadly representative of the long-term evolution of lithic technology. These are bipolar, multiplatform, discoidal, biface, Levallois, prismatic blade, punch blade and pressure blade production. Raw material efficiency is assessed by the ratio of cutting edge length to original core mass. We also examine which flake attributes contribute to maximising raw material efficiency, as well as compare the difference between expert and intermediate knappers in terms of cutting edge produced per gram of core. We identify a gradual increase in raw material efficiency over the broad sweep of lithic technological evolution. The results indicate that the most significant transition in efficiency likely took place with the introduction of small foliate biface, Levallois and prismatic blade knapping, all introduced in the Middle Stone Age / Middle Palaeolithic among early Homo sapiens and Neanderthals. This suggests that no difference in raw material efficiency existed between these species. With prismatic blade technology securely dated to the Middle Palaeolithic, by including the more recent punch and pressure blade technology our results dispel the notion that the transition to the Upper Palaeolithic was accompanied by an increase in efficiency. However, further increases in cutting edge efficiency are evident, with pressure blades possessing the highest efficiency in this study, indicating that late/epi-Palaeolithic and Neolithic blade technologies further increased efficiency.

  13. On the evolution of a retracting straight liquid sheet edge: experimental study

    Science.gov (United States)

    Krechetnikov, Rouslan; Mayer, Hans C.

    2011-11-01

    The evolution of the initially straight edge of a retracting liquid sheet is still a subject of debate. Theoretical and numerical studies have provided conflicting results, and experimental efforts have, to our knowledge, never been attempted owing to the difficulty in achieving a uniform edge. However, recent advances in experimental techniques, specifically those presented in detail in Poster #72 of APS-DFD 2010 (H.C. Mayer and R. Krechetnikov), have allowed us to uniformly detach a soap film from a straight edge using an impulsively heated wire frame. The detachment, retraction, and breakup of soap films (h ~ 10 μm) is analyzed using high speed photography. Owing to the Plateau border that connects the uniform film to the wire frames (wire diameter 25-250 μm) - a feature not present when rupturing films from a point - the early stages of retraction are dominated by a relatively large rim mass. We explore the phenomena at very early times (t films which may add complexity to the problem of determining what instability mechanism(s) are responsible for their breakup.

  14. Three-Dimensional Graphene Networks with Abundant Sharp Edge Sites for Efficient Electrocatalytic Hydrogen Evolution.

    Science.gov (United States)

    Yu, Gui; Wang, Huping; Li, Xu-Bing; Gao, Lei; Wu, Hao-Lin; Yang, Jie; Cai, Le; Ma, Tian-Bao; Tung, Chen-Ho; Wu, Li-Zhu

    2017-11-11

    To achieve sustainable production of hydrogen (H2) through water splitting, establishing efficient and earth-abundant electrocatalysts is of great necessity. Here, we firstly reveal that morphology engineering of graphene can modulate the electronic structure of carbon skeleton and in turn endow it with excellent ability of proton reduction. Three-dimensional (3D) graphene networks with the high density of sharp edge sites are synthesized. Electrocatalytic measurements indicate that the obtained 3D graphene networks can electrocatalyze H2 evolution with an extremely low onset potential of ~18 mV in 0.5 M H2SO4 solution, together with good stability. A combination of control experiments and density functional theory (DFT) investigations indicates that the exceptional H2 evolution performance is attributed to the abundant sharp-edge sites of the advanced frameworks, which are responsible for promoting the adsorption and reduction of protons. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Evolution patterns and parameter regimes in edge localized modes on the National Spherical Torus Experiment

    Science.gov (United States)

    Smith, D. R.; Fonck, R. J.; McKee, G. R.; Diallo, A.; Kaye, S. M.; LeBlanc, B. P.; Sabbagh, S. A.

    2016-04-01

    We implement unsupervised machine learning techniques to identify characteristic evolution patterns and associated parameter regimes in edge localized mode (ELM) events observed on the National Spherical Torus Experiment. Multi-channel, localized measurements spanning the pedestal region capture the complex evolution patterns of ELM events on Alfvén timescales. Some ELM events are active for less than 100 μs, but others persist for up to 1 ms. Also, some ELM events exhibit a single dominant perturbation, but others are oscillatory. Clustering calculations with time-series similarity metrics indicate the ELM database contains at least two and possibly three groups of ELMs with similar evolution patterns. The identified ELM groups trigger similar stored energy loss, but the groups occupy distinct parameter regimes for ELM-relevant quantities like plasma current, triangularity, and pedestal height. Notably, the pedestal electron pressure gradient is not an effective parameter for distinguishing the ELM groups, but the ELM groups segregate in terms of electron density gradient and electron temperature gradient. The ELM evolution patterns and corresponding parameter regimes can shape the formulation or validation of nonlinear ELM models. Finally, the techniques and results demonstrate an application of unsupervised machine learning at a data-rich fusion facility.

  16. Impact of sheath evolution on ion impinging energy on the target during edge localized modes

    Science.gov (United States)

    Dai, Shuyu; Wang, Dezhen

    2018-01-01

    The impact of the sheath evolution during edge localized modes (ELMs) on the ion impinging energy on the divertor target is studied by particle-in-cell simulation. A significant increase of the ion impact energy is obtained at the beginning of ELM. The arrival of the upstream bulk plasma leads to a suppression of the potential drop in front of the divertor target. The peak value of the ion impact energy emerges after the maximum potential drop in front of the divertor target. It is found that the peak value of the ion impact energy is increased by about 30% compared to the ion initial energy, which is induced by the potential drop during ELMs.

  17. EVolution: an edge-based variational method for non-rigid multi-modal image registration

    Science.gov (United States)

    de Senneville, B. Denis; Zachiu, C.; Ries, M.; Moonen, C.

    2016-10-01

    Image registration is part of a large variety of medical applications including diagnosis, monitoring disease progression and/or treatment effectiveness and, more recently, therapy guidance. Such applications usually involve several imaging modalities such as ultrasound, computed tomography, positron emission tomography, x-ray or magnetic resonance imaging, either separately or combined. In the current work, we propose a non-rigid multi-modal registration method (namely EVolution: an edge-based variational method for non-rigid multi-modal image registration) that aims at maximizing edge alignment between the images being registered. The proposed algorithm requires only contrasts between physiological tissues, preferably present in both image modalities, and assumes deformable/elastic tissues. Given both is shown to be well suitable for non-rigid co-registration across different image types/contrasts (T1/T2) as well as different modalities (CT/MRI). This is achieved using a variational scheme that provides a fast algorithm with a low number of control parameters. Results obtained on an annotated CT data set were comparable to the ones provided by state-of-the-art multi-modal image registration algorithms, for all tested experimental conditions (image pre-filtering, image intensity variation, noise perturbation). Moreover, we demonstrate that, compared to existing approaches, our method possesses increased robustness to transient structures (i.e. that are only present in some of the images).

  18. Active Edge Sites Engineering in Nickel Cobalt Selenide Solid Solutions for Highly Efficient Hydrogen Evolution

    KAUST Repository

    Xia, Chuan

    2017-01-06

    An effective multifaceted strategy is demonstrated to increase active edge site concentration in NiCoSe solid solutions prepared by in situ selenization process of nickel cobalt precursor. The simultaneous control of surface, phase, and morphology result in as-prepared ternary solid solution with extremely high electrochemically active surface area (C = 197 mF cm), suggesting significant exposure of active sites in this ternary compound. Coupled with metallic-like electrical conductivity and lower free energy for atomic hydrogen adsorption in NiCoSe, identified by temperature-dependent conductivities and density functional theory calculations, the authors have achieved unprecedented fast hydrogen evolution kinetics, approaching that of Pt. Specifically, the NiCoSe solid solutions show a low overpotential of 65 mV at -10 mV cm, with onset potential of mere 18 mV, an impressive small Tafel slope of 35 mV dec, and a large exchange current density of 184 μA cm in acidic electrolyte. Further, it is shown that the as-prepared NiCoSe solid solution not only works very well in acidic electrolyte but also delivers exceptional hydrogen evolution reaction (HER) performance in alkaline media. The outstanding HER performance makes this solid solution a promising candidate for mass hydrogen production.

  19. Pedestal and E r profile evolution during an edge localized mode cycle at ASDEX Upgrade

    Science.gov (United States)

    Cavedon, M.; Pütterich, T.; Viezzer, E.; Laggner, F. M.; Burckhart, A.; Dunne, M.; Fischer, R.; Lebschy, A.; Mink, F.; Stroth, U.; Willensdorfer, M.; Wolfrum, E.; the ASDEX Upgrade Team

    2017-10-01

    The upgrade of the edge charge exchange recombination spectroscopy diagnostic at ASDEX Upgrade has enabled highly spatially resolved measurements of the impurity ion dynamics during an edge-localized mode cycle (ELM) with unprecedented temporal resolution, i.e. 65 μs. The increase of transport during an ELM induces a relaxation of the ion, electron edge gradients in impurity density and flows. Detailed characterization of the recovery of the edge temperature gradients reveals a difference in the ion and electron channel: the maximum ion temperature gradient {{\

  20. Velocity and Drag Evolution From the Leading Edge of a Model Mangrove Forest

    Science.gov (United States)

    Maza, Maria; Adler, Katherine; Ramos, Diogo; Garcia, Adrian Mikhail; Nepf, Heidi

    2017-11-01

    An experimental study of unidirectional flow through a model mangrove forest measured both velocity and forces on individual trees. The individual trees were 1/12th scale models of mature Rhizophora, including 24 prop roots distributed in a three-dimensional layout. Thirty-two model trees were distributed in a staggered array producing a 2.5 m long forest. The velocity evolved from a boundary layer profile at the forest leading edge to a vertical profile determined by the vertical distribution of frontal area, with significantly higher velocity above the prop roots. Fully developed conditions were reached at the fifth tree row from the leading edge. Within the root zone the velocity was reduced by up to 50% and the TKE was increased by as much as fivefold, relative to the upstream conditions. TKE in the root zone was mainly produced by root and trunk wakes, and it agreed in magnitude with the estimation obtained using the Tanino and Nepf (2008) formulation. Maximum TKE occurred at the top of the roots, where a strong shear region was associated with the change in frontal area. The drag measured on individual trees decreased from the leading edge and reached a constant value at the fifth row and beyond, i.e., in the fully developed region. The drag exhibited a quadratic dependence on velocity, which justified the definition of a quadratic drag coefficient. Once the correct drag length-scale was defined, the measured drag coefficients collapsed to a single function of Reynolds number.

  1. Identification of Active Edge Sites for Electrochemical H2 Evolution from MoS2 Nanocatalysts

    DEFF Research Database (Denmark)

    Jaramillo, Thomas; Jørgensen, Kristina Pilt; Bonde, Jacob

    2007-01-01

    The identification of the active sites in heterogeneous catalysis requires a combination of surface sensitive methods and reactivity studies. We determined the active site for hydrogen evolution, a reaction catalyzed by precious metals, on nanoparticulate molybdenum disulfide (MoS2) by atomically...

  2. The double edged sword: The demographic consequences of the evolution of self-fertilization.

    Science.gov (United States)

    Abu Awad, Diala; Billiard, Sylvain

    2017-05-01

    Phylogenies indicate that the transition from outcrossing to selfing is frequent, with selfing populations being more prone to extinction. The rates of transition to selfing and extinction, acting on different timescales, could explain the observed distributions of extant selfing species among taxa. However, phylogenetic and theoretical studies consider these mechanisms independently, that is transitions do not cause extinction. Here, we theoretically explore the demographic consequences of the evolution of self-fertilization. Deleterious mutations and mutations modifying the selfing rate are recurrently introduced and the number of offspring depends on individual fitness, allowing for a demographic feedback. We show that mutational meltdowns can be triggered in populations evolving near strict selfing. Populations having survived a demographic crash are more stable than ancestral outcrossing populations once deleterious mutations are purged. The relatively rapid time-scales at which extinctions occur indicate that during evolutionary transitions the accumulation of deleterious mutations may not be the cause of extinctions observed on longer time scales, but could lead to the underestimation of transition rates from outcrossing to selfing. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  3. Sub-microsecond temporal evolution of edge density during edge localized modes in KSTAR tokamak plasmas inferred from ion cyclotron emission

    Science.gov (United States)

    Chapman, B.; Dendy, R. O.; McClements, K. G.; Chapman, S. C.; Yun, G. S.; Thatipamula, S. G.; Kim, M. H.

    2017-12-01

    During edge localised mode (ELM) crashes in KSTAR deuterium plasmas, bursts of spectrally structured ion cyclotron emission (ICE) are detected. Usually the ICE spectrum chirps downwards during an ELM crash, on sub-microsecond timescales. For KSTAR ICE where the separation of spectral peak frequencies is close to the proton cyclotron frequency Ω_cp at the outer plasma edge, we show that the driving population of energetic ions is likely to be a subset of the 3 MeV fusion protons, born centrally on deeply passing orbits which drift from the core to the edge plasma. We report first principles modelling of this scenario using a particle-in-cell code, which evolves the full orbit dynamics of large numbers of energetic protons, thermal deuterons, and electrons self-consistently with the electric and magnetic fields. The Fourier transform of the excited fields in the nonlinear saturated regime of the simulations is the theoretical counterpart to the measured ICE spectra. Multiple simulation runs for different, adjacent, values of the plasma density under KSTAR edge conditions enable us to infer the theoretical dependence of ICE spectral structure on the local electron number density. By matching this density dependence to the observed time-dependence of chirping ICE spectra in KSTAR, we obtain sub-microsecond time resolution of the evolving local electron number density during the ELM crash.

  4. Dimeric [Mo₂S₁₂]²⁻ Cluster: A Molecular Analogue of MoS₂ Edges for Superior Hydrogen-Evolution Electrocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Zhongjie; Luo, Wenjia; Ma, Lu; Yu, Mingzhe; Ren, Xiaodi; He, Mingfu; Polen, Shan; Click, Kevin; Garrett, Benjamin R.; Lu, Jun; Amine, Khalil

    2015-12-07

    Proton reduction is one of the most fundamental and important reactions in nature. MoS2 edges have been identified as the active sites for hydrogen evolution reaction (HER) electrocatalysis. Designing molecular mimics of MoS2 edge sites is an attractive strategy to understand the underlying catalytic mechanism of different edge sites and improve their activities. Herein we report a dimeric molecular analogue [Mo₂S₁₂]²⁻, as the smallest unit possessing both the terminal and bridging disulfide ligands. Our electrochemical tests show that [Mo₂S₁₂]²⁻ is a superior heterogeneous HER catalyst under acidic conditions. Computations suggest that the bridging disulfide ligand of [Mo₂S₁₂]²⁻ exhibits a hydrogen adsorption free energy near zero (-0.05eV). This work helps shed light on the rational design of HER catalysts and biomimetics of hydrogen-evolving enzymes.

  5. Evolution in the Dust Lane Fraction of Edge-on L* V Spiral Galaxies Since z = 0.8

    Science.gov (United States)

    Holwerda, B. W.; Dalcanton, J. J.; Radburn-Smith, D.; de Jong, R. S.; Guhathakurta, P.; Koekemoer, A.; Allen, R. J.; Böker, T.

    2012-07-01

    The presence of a well-defined and narrow dust lane in an edge-on spiral galaxy is the observational signature of a thin and dense molecular disk, in which gravitational collapse has overcome turbulence. Using a sample of galaxies out to z ~ 1 extracted from the COSMOS survey, we identify the fraction of massive (L* V ) disks that display a dust lane. Our goal is to explore the evolution in the stability of the molecular interstellar medium (ISM) disks in spiral galaxies over a cosmic timescale. We check the reliability of our morphological classifications against changes in rest-frame wavelength, resolution, and cosmic dimming with (artificially redshifted) images of local galaxies from the Sloan Digital Sky Survey. We find that the fraction of L* V disks with dust lanes in COSMOS is consistent with the local fraction (≈80%) out to z ~ 0.7. At z = 0.8, the dust lane fraction is only slightly lower. A somewhat lower dust lane fraction in starbursting galaxies tentatively supports the notion that a high specific star formation rate can efficiently destroy or inhibit a dense molecular disk. A small subsample of higher redshift COSMOS galaxies display low internal reddening (E[B - V]), as well as a low incidence of dust lanes. These may be disks in which the growth of the dusty ISM disk lags behind that of the stellar disk. We note that at z = 0.8, the most massive galaxies display a lower dust lane fraction than lower mass galaxies. A small contribution of recent mergers or starbursts to this most massive population may be responsible. The fact that the fraction of galaxies with dust lanes in COSMOS is consistent with little or no evolution implies that models to explain the spectral energy distribution or the host galaxy dust extinction of supernovae based on local galaxies are still applicable to higher redshift spirals. It also suggests that dust lanes are long-lived phenomena or can be reformed over very short timescales.

  6. A strategy to synergistically increase the number of active edge sites and the conductivity of MoS2 nanosheets for hydrogen evolution

    Science.gov (United States)

    Yu, Hailong; Yu, Xianbo; Chen, Yujin; Zhang, Shen; Gao, Peng; Li, Chunyan

    2015-05-01

    Nanostructured MoS2 is very promising as an electrocatalyst for hydrogen evolution due to a greater number of active edge sites. However, a very large resistance between basal planes decreases the overall efficiency of hydrogen evolution, and greatly limits its application in industry. Herein we develop a facile strategy to synergistically increase the number of active edge sites and the conductivity of MoS2. MoS2 nanosheet arrays can be grown vertically on a carbon fiber cloth (CFC) substrates by a facile strategy. On the one hand, ammonium fluoride in the reaction system could effectively etch the inert basal plane of the MoS2 nanosheets, leading to the formation of pits in the inert basal plane of the MoS2 nanosheets. Thereby the number of active edge sites is significantly increased. On the other hand, the vertical growth of MoS2 nanosheet arrays on CFCs can significantly decrease the resistance of MoS2-based electrocatalysts. As a result, the MoS2-based electrocatalysts exhibit excellent catalytic activity for hydrogen evolution reactions, with a small Tafel slope and a large cathodic current density. Moreover, the CFC can be repeatedly utilized as a template to grow ultrathin MoS2 nanosheet arrays for HERs. The excellent activity and recyclable utilization, as well as mass production, indicate that the composite has promising applications in industry.Nanostructured MoS2 is very promising as an electrocatalyst for hydrogen evolution due to a greater number of active edge sites. However, a very large resistance between basal planes decreases the overall efficiency of hydrogen evolution, and greatly limits its application in industry. Herein we develop a facile strategy to synergistically increase the number of active edge sites and the conductivity of MoS2. MoS2 nanosheet arrays can be grown vertically on a carbon fiber cloth (CFC) substrates by a facile strategy. On the one hand, ammonium fluoride in the reaction system could effectively etch the inert basal

  7. Measurements of the edge current evolution and comparison with neoclassical calculations during MAST H-modes using motional Stark effect

    NARCIS (Netherlands)

    de Bock, M. F. M.; Citrin, J.; Saarelma, S.; Temple, D.; Conway, N. J.; Kirk, A.; Meyer, H.; Michael, C. A.

    2012-01-01

    Edge localized modes (ELMs), that are present in most tokamak H-(high confinement) modes, can cause significant damage to plasma facing components in fusion reactors. Controlling ELMs is considered necessary and hence it is vital to understand the underlying physics. The stability of ELMs is

  8. Electrochemical maps and movies of the hydrogen evolution reaction on natural crystals of molybdenite (MoS2): basal vs. edge plane activity.

    Science.gov (United States)

    Bentley, Cameron L; Kang, Minkyung; Maddar, Faduma M; Li, Fengwang; Walker, Marc; Zhang, Jie; Unwin, Patrick R

    2017-09-01

    Two dimensional (2D) semiconductor materials, such as molybdenum disulfide (MoS2) have attracted considerable interest in a range of chemical and electrochemical applications, for example, as an abundant and low-cost alternative electrocatalyst to platinum for the hydrogen evolution reaction (HER). While it has been proposed that the edge plane of MoS2 possesses high catalytic activity for the HER relative to the "catalytically inert" basal plane, this conclusion has been drawn mainly from macroscale electrochemical (voltammetric) measurements, which reflect the "average" electrocatalytic behavior of complex electrode ensembles. In this work, we report the first spatially-resolved measurements of HER activity on natural crystals of molybdenite, achieved using voltammetric scanning electrochemical cell microscopy (SECCM), whereby pixel-resolved linear-sweep voltammogram (LSV) measurements have allowed the HER to be visualized at multiple different potentials to construct electrochemical flux movies with nanoscale resolution. Key features of the SECCM technique are that characteristic surface sites can be targeted and analyzed in detail and, further, that the electrocatalyst area is known with good precision (in contrast to many macroscale measurements on supported catalysts). Through correlation of the local voltammetric response with information from scanning electron microscopy (SEM) and atomic force microscopy (AFM) in a multi-microscopy approach, it is demonstrated unequivocally that while the basal plane of bulk MoS2 (2H crystal phase) possesses significant activity, the HER is greatly facilitated at the edge plane (e.g., surface defects such as steps, edges or crevices). Semi-quantitative treatment of the voltammetric data reveals that the HER at the basal plane of MoS2 has a Tafel slope and exchange current density (J0) of ∼120 mV per decade and 2.5 × 10-6 A cm-2 (comparable to polycrystalline Co, Ni, Cu and Au), respectively, while the edge plane has a

  9. Towards a physics of evolution: Critical diversity dynamics at the edges of collapse and bursts of diversification

    Science.gov (United States)

    Hanel, Rudolf; Kauffman, Stuart A.; Thurner, Stefan

    2007-09-01

    Systems governed by the standard mechanisms of biological or technological evolution are often described by catalytic evolution equations. We study the structure of these equations and find an analogy with classical thermodynamic systems. In particular, we can demonstrate the existence of several distinct phases of evolutionary dynamics: a phase of fast growing diversity, one of stationary, finite diversity, and one of rapidly decaying diversity. While the first two phases have been subject to previous work, here we focus on the destructive aspects—in particular the phase diagram—of evolutionary dynamics. The main message is that within a critical region, massive loss of diversity can be triggered by very small external fluctuations. We further propose a dynamical model of diversity which captures spontaneous creation and destruction processes fully respecting the phase diagrams of evolutionary systems. The emergent time series show rich diversity dynamics, including power laws as observed in actual economical data, e.g., firm bankruptcy data. We believe the present model presents a possibility to cast the famous qualitative picture of Schumpeterian economic evolution, into a quantifiable and testable framework.

  10. UniEdge: A first year transition program and its continued evolution through a reflective approach. A Practice Report

    Directory of Open Access Journals (Sweden)

    Ann Lefroy

    2014-03-01

    Full Text Available Phillipa Sturgess 14.00 800x600 The shift in Australian higher education policy to widen participation and ensure equity across all student cohorts has led to the need for specific, structured transition programs. The First Year Advisor Network at Murdoch University in Perth, Australia has designed and implemented a transition program for commencing students called UniEdge. The aims of the program are: (1 to help foster a sense of community for first year students; (2 to  make new students aware of the support services available; and (3 to improve the confidence and preparedness of new students. The program has received high praise from students, but rates of attendance have been problematic. By reflecting on student and staff feedback, the program has been adapted over multiple semesters, resulting in increased student attendance and therefore a greater impact on the first year experience at Murdoch University. Normal 0 false false false EN-AU X-NONE X-NONE

  11. Curling into the hole: drainage evolution at the edge of a sinking slab (Guadalhorce River, westernmost Mediterranean)

    Science.gov (United States)

    Pérez Peña, José Vicente; Booth Rea, Guillermo; Azañón, José Miguel; Morales, José; de Lis Mancilla, Flor; Stich, Daniel; Galve, Jorge Pedro

    2017-04-01

    Dynamic topography related to mantle processes is an important factor controlling landscape and drainage network evolution. Dense slabs induce an upper mantle flow that deflects the topography downward above them. Topographic anomalies caused by these mechanisms have a long-wavelength and normally remain masked by other tectonic mechanisms that deform the surface at smaller wavelengths. Therefore, the geomorphic evidence of these mantle mechanisms are not so frequent in active orogens. In the central Betics (westernmost Mediterranean), sharp differences in crustal thickness do not match with topographic gradients, thus necessitating support by mantle-related mechanisms. In this work we analyzed the topographic and drainage network evolution of the Guadalhorce drainage basin, located in the central Betics. The northern part of this basin was captured in Pleistocene times following a very distinctive radial pattern. The main channels in the north deviate into the Malaga basin depicting sharp U-turns. High-resolution crustal imaging by P-receiver functions allows us to identify a bend of the Iberian Moho at the top of the Alboran sinking slab. Different topography filters at different wavelengths show a long-scale topographic depression that lies above the Iberian Moho bend. The central and middle part of the basin lies over this depression and the drainage network flows orthogonal to the main gradient of the Iberian Moho. Therefore, the Alboran sinking slab produces a negative dynamic topography that is curling the drainage network towards it.

  12. Structural evolution of fluorinated graphene upon molten-alkali treatment probed by X-ray absorption near-edge structure spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Xianqing, E-mail: lxq@gxu.edu.cn [Guangxi Colleges and Universities Key Laboratory of Novel Energy Materials and Related Technology, College of Physics Science and Technology, Guangxi University, Nanning 530004 (China); Guangxi Collaborative Innovation Center of Structure and Property for New Energy and Materials, School of Material Science and Engineering, Guilin University of Electronic Technology, Guilin 541004 (China); Pan, Deyou; Lao, Ming; Liang, Shuiying [Guangxi Colleges and Universities Key Laboratory of Novel Energy Materials and Related Technology, College of Physics Science and Technology, Guangxi University, Nanning 530004 (China); Huang, Dan; Zhou, Wenzheng; Guo, Jin [Guangxi Colleges and Universities Key Laboratory of Novel Energy Materials and Related Technology, College of Physics Science and Technology, Guangxi University, Nanning 530004 (China); Guangxi Collaborative Innovation Center of Structure and Property for New Energy and Materials, School of Material Science and Engineering, Guilin University of Electronic Technology, Guilin 541004 (China)

    2017-05-15

    Highlights: • Structural evolution of FG during the molten-alkali treatment was studied. • XANES results reveal the transformation of surface functional groups of HFG. • The local and electronic structure of HFG can be tuned by varying the alkali-FG ratio. - Abstract: The structural evolution of fluorinated graphene (FG) nanosheets upon molten-alkali treatment has been systematically investigated utilizing X-ray absorption near-edge structure (XANES) spectroscopy. It is found that the hydroxyl groups can progressively displace fluorine atoms to form covalent bonds to the graphene sheets under designed molten-alkali condition. The XANES spectra also reveal the formation of epoxide groups through intramolecular dehydration of neighbouring hydroxyl groups after substitution reaction. At high alkali-FG weight ratio, the restoration of the π-conjugated structure in graphene sheets can be observed due to the gradual decomposition of epoxide groups. Our experimental results indicate that the surface chemistry and electronic structure of hydroxyl-functionalized FG (HFG) can be readily tuned by varying the ratio of reactants.

  13. Fault fluid evolution at the outermost edges of the southern Apennines fold-and-thrust belt, Italy

    Science.gov (United States)

    Agosta, Fabrizio; Belviso, Claudia; Cavalcante, Francesco; Vita Petrullo, Angela

    2017-04-01

    This work focuses on the structural architecture and mineralization of a high-angle, extensional fault zone that crosscuts the Middle Pleistocene tuffs and pyroclastites of the Vulture Volcano, southern Italy. This fault zone is topped by a few m-thick travertine deposit formed by precipitation, in a typical lacustrine depositional environment, from a fault fluid that included a mixed, biogenic- and mantle-derived CO2. The detailed analysis of its different mineralization can shed new lights into the shallow crustal fluid flow that took place during deformation of the outer edge of the southern Apennines fold-and-thrust belt. In fact, the study fault zone is interpreted as a shallow-seated, tear fault associated with a shallow thrust fault displacing the most inner portion of the Bradano foredeep basin infill, and was thus active during the latest stages of contractional deformation. Far from the fault zone, the fracture network is made up of three high-angle joint sets striking N-S, E-W and NW-SE, respectively. The former two sets can be interpreted as the older structural elements that pre-dated the latter one, which is likely due to the current stress state that affects the whole Italian peninsula. In the vicinity of the fault zone, a fourth joint high-angle set striking NE-SW is also present, which becomes the most dominant fracture set within the study footwall fault damage zone. Detailed X-ray diffraction analysis of the powder obtained from hand specimens representative of the multiple mineralization present within the fault zone, and in the surrounding volcanites, are consistent with circulation of a fault fluid that modified its composition with time during the latest stages of volcanic activity and contractional deformation. Specifically, veins infilled with and slickenside coated by jarosite, Opal A and/or goethite are found in the footwall fault damage zone. Based upon the relative timing of formation of the aforementioned joint sets, deciphered after

  14. Edge Bioinformatics

    Energy Technology Data Exchange (ETDEWEB)

    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

  15. Depositional architecture and evolution of inner shelf to shelf edge delta systems since the Late Oliocene and their respone to the tectonic and sea level change, Pear River Mouth Basin, northern South China Sea

    Science.gov (United States)

    Lin, Changsong; Zhang, Zhongtao; liu, Jingyan; Jiang, Jing

    2016-04-01

    The Pear River Mouth Basin is located in the northern continent margin of the South China Sea. Since the Late Oligocene, the long-term active fluvial systems (Paleo-Zhujiang) from the western basin margin bebouched into the northern continental margin of the South China Sea and formed widespread deltaic deposits in various depositional geomorphologies and tectonic settings. Based of integral analysys of abundant seismic, well logging and drilling core data, Depositional architecture and evolution of these delta systems and their respone to the tectonic and sea level change are documented in the study. There are two basic types of the delta systems which have been recognized: inner shelf delta deposited in shallow water enviroments and the outer shelf or shelf-edge delta systems occurred in deep water settings. The paleowater depths of these delta systems are around 30 to 80m (inner shelf delta) and 400-1000m (shelf-edge delta) estimated from the thickness (decompaction) of the delta front sequences. The study shows that the inner shelf delta systems are characterized by relatively thin delta forests (20-40m), numereous stacked distributary channel fills, relative coarse river mouth bar deposits and thin distal delta front or distal bar and prodelta deposits. In contrast, the outer shelf or shelf edge delta systems are characteristic of thick (300-800m) and steep (4-60) of deltaic clinoforms, which commonly display in 3D seismic profiles as "S" shape reflection. Large scale soft-sediment deformation structures, slump or debris flow deposits consisting mainly of soft-sediment deformed beds, blocks of sandstones and siltstones or mudstones widely developed in the delta front deposits. The shelf edge delta systems are typically associated with sandy turbidite fan deposits along the prodelta slopes, which may shift basinwards as the progradation of the delta systems. The delta systems underwent several regional cycles of evolution from inner shelf deltas to shelf edge

  16. Edge Detection,

    Science.gov (United States)

    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

  17. Living edge

    DEFF Research Database (Denmark)

    Earon, Ofri

    2014-01-01

    was originally introduced to enhance indoor qualities including light and view. Throughout the paper, it is argued that these ecological motives have grown to architectural and urban dimensions. The paper analyzes the characteristics and potentials of these dimensions and their interconnections. The paper...... on the ground level, but there is a lack of recognition in the significance of communicative characters as well at the higher part of the edge. The city’s planning approach is “Consider urban life before urban space. Consider urban space before buildings” This urban strategy neglects the possible architectural...... contribution to the street atmosphere and its effect on urban life. Bay balcony has been a common architectural element in Copenhagen’s residential buildings, since the end of the twenties. It is a domestic border with an architectural thickness combining window, door, windowsill and balcony. The bay balcony...

  18. Evolution

    Science.gov (United States)

    Peter, Ulmschneider

    When we are looking for intelligent life outside the Earth, there is a fundamental question: Assuming that life has formed on an extraterrestrial planet, will it also develop toward intelligence? As this is hotly debated, we will now describe the development of life on Earth in more detail in order to show that there are good reasons why evolution should culminate in intelligent beings.

  19. Evolution of phosphorus complexation and mineralogy during (hydro)thermal treatments of activated and anaerobically digested sludge: Insights from sequential extraction and P K-edge XANES.

    Science.gov (United States)

    Huang, Rixiang; Tang, Yuanzhi

    2016-09-01

    (Hydro)thermal treatments of sewage sludge is a promising option that can simultaneously target safe waste disposal, energy recovery, and nutrient recovery/recycling. The speciation of phosphorus (P) in sludge is of great relevance to P reclamation/recycling and soil application of sludge-derived products, thus it is critical to understand the effects of different treatment techniques and conditions on P speciation. This study systematically characterized P speciation (i.e. complexation and mineral forms) in chars derived from pyrolysis and hydrothermal carbonization (HTC) of municipal sewage sludges. Combined sequential extraction and P K-edge X-ray absorption near edge structure (XANES) spectroscopy analysis revealed the dependence of P transformation on treatment conditions and metal composition in the feedstocks. Pyrolysis of sludges decreased the relative abundance of phytic acid while increased the abundance of Al-associated P. HTC thoroughly homogenized and exposed P for interaction with various metals/minerals, with the final P speciation closely related to the composition/speciation of metals and their affinities to P. Results from this study revealed the mechanisms of P transformation during (hydro)thermal treatments of sewage sludges, and might be applicable to other biosolids. It also provided fundamental knowledge basis for the design and selection of waste management strategies for better P (re)cycling and reclamation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Influence of Dynamical Change of Edges on Clustering Coefficients

    Directory of Open Access Journals (Sweden)

    Yuhong Ruan

    2015-01-01

    Full Text Available Clustering coefficient is a very important measurement in complex networks, and it describes the average ratio between the actual existent edges and probable existent edges in the neighbor of one vertex in a complex network. Besides, in a complex networks, the dynamic change of edges can trigger directly the evolution of network and further affect the clustering coefficients. As a result, in this paper, we investigate the effects of the dynamic change of edge on the clustering coefficients. It is illustrated that the increase and decrease of the clustering coefficient can be effectively controlled by adding or deleting several edges of the network in the evolution of complex networks.

  1. Cascading Edge Failures: A Dynamic Network Process

    CERN Document Server

    Zhang, June

    2016-01-01

    This paper considers the dynamics of edges in a network. The Dynamic Bond Percolation (DBP) process models, through stochastic local rules, the dependence of an edge $(a,b)$ in a network on the states of its neighboring edges. Unlike previous models, DBP does not assume statistical independence between different edges. In applications, this means for example that failures of transmission lines in a power grid are not statistically independent, or alternatively, relationships between individuals (dyads) can lead to changes in other dyads in a social network. We consider the time evolution of the probability distribution of the network state, the collective states of all the edges (bonds), and show that it converges to a stationary distribution. We use this distribution to study the emergence of global behaviors like consensus (i.e., catastrophic failure or full recovery of the entire grid) or coexistence (i.e., some failed and some operating substructures in the grid). In particular, we show that, depending on...

  2. Nanoindentation near the edge

    Science.gov (United States)

    J.E. Jakes; C.R. Frihart; J.F. Beecher; R.J. Moon; P.J. Resto; Z.H. Melgarejo; O.M. Saurez; H. Baumgart; A.A. Elmustafa; D.S. Stone

    2009-01-01

    Whenever a nanoindent is placed near an edge, such as the free edge of the specimen or heterophase interface intersecting the surface, the elastic discontinuity associated with the edge produces artifacts in the load-depth data. Unless properly handled in the data analysis, the artifacts can produce spurious results that obscure any real trends in properties as...

  3. Edge colouring by total labellings

    DEFF Research Database (Denmark)

    Brandt, Stephan; Rautenbach, D.; Stiebitz, M.

    2010-01-01

    We introduce the concept of an edge-colouring total k-labelling. This is a labelling of the vertices and the edges of a graph G with labels 1, 2, ..., k such that the weights of the edges define a proper edge colouring of G. Here the weight of an edge is the sum of its label and the labels of its...

  4. Adobe Edge Quickstart Guide

    CERN Document Server

    Labrecque, Joseph

    2012-01-01

    Adobe Edge Quickstart Guide is a practical guide on creating engaging content for the Web with Adobe's newest HTML5 tool. By taking a chapter-by-chapter look at each major aspect of Adobe Edge, the book lets you digest the available features in small, easily understandable chunks, allowing you to start using Adobe Edge for your web design needs immediately. If you are interested in creating engaging motion and interactive compositions using web standards with professional tooling, then this book is for you. Those with a background in Flash Professional wanting to get started quickly with Adobe

  5. Adobe Edge Preview 3

    CERN Document Server

    Grover, Chris

    2011-01-01

    Want to use an Adobe tool to design animated web graphics that work on iPhone and iPad? You've come to the right book. Adobe Edge Preview 3: The Missing Manual shows you how to build HTML5 graphics using simple visual tools. No programming experience? No problem. Adobe Edge writes the underlying code for you. With this eBook, you'll be designing great-looking web elements in no time. Get to know the workspace. Learn how Adobe Edge Preview 3 performs its magic.Create and import graphics. Make drawings with Edge's tools, or use art you designed in other programs.Work with text. Build menus, lab

  6. Edge Simulation Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Krasheninnikov, Sergei I. [Univ. of California, San Diego, CA (United States); Angus, Justin [Univ. of California, San Diego, CA (United States); Lee, Wonjae [Univ. of California, San Diego, CA (United States)

    2018-01-05

    The goal of the Edge Simulation Laboratory (ESL) multi-institutional project is to advance scientific understanding of the edge plasma region of magnetic fusion devices via a coordinated effort utilizing modern computing resources, advanced algorithms, and ongoing theoretical development. The UCSD team was involved in the development of the COGENT code for kinetic studies across a magnetic separatrix. This work included a kinetic treatment of electrons and multiple ion species (impurities) and accurate collision operators.

  7. The Edge supersonic transport

    Science.gov (United States)

    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).

  8. EdgeCentric: Anomaly Detection in Edge-Attributed Networks

    OpenAIRE

    Shah, Neil; Beutel, Alex; Hooi, Bryan; Akoglu, Leman; Gunnemann, Stephan; Makhija, Disha; Kumar, Mohit; Faloutsos, Christos

    2015-01-01

    Given a network with attributed edges, how can we identify anomalous behavior? Networks with edge attributes are commonplace in the real world. For example, edges in e-commerce networks often indicate how users rated products and services in terms of number of stars, and edges in online social and phonecall networks contain temporal information about when friendships were formed and when users communicated with each other -- in such cases, edge attributes capture information about how the adj...

  9. Edge domination in grids

    DEFF Research Database (Denmark)

    Klostermeyer, William F.; Yeo, Anders

    2015-01-01

    It has been conjectured that the edge domination number of the m × n grid graph, denoted by γ′(Pm□Pn), is ⌊mn/3⌋, when m,n ≥ 2. Our main result gives support for this conjecture by proving that ⌊mn/3⌋ ≤ -γ′{Pm□Pn) ≤ mn/3 + n/12 + 1, when m,n ≥ 2. We furthermore show that the conjecture holds when...

  10. Off the edge

    OpenAIRE

    Stoneham, Luke

    2014-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and was awarded by Brunel University London. Work which takes from elsewhere forms an important thread in European art music. There is a long tradition of music which variously borrows, thieves, pastiches, plagiarises, ironically ‘retakes’, hoaxes, impersonates and appropriates. The music I have written for Off the edge, while seeking to honour and add to this thread, also attempts to zoom in upon and make explicit the idea o...

  11. Edge Relaxation and Boundary Continuity.

    Science.gov (United States)

    1980-05-01

    V. Measures of Performance 94 1. Fixed Points, Entropy , and Consistency 94 2. Global Measures of Uncertainty, Drift, and Inconsistency 96 VI...operators have been applied. Marr EMARR763 uses a set of edge detectors of varying size to determine the appropriate width of an edge to be asserted in his...certain edges is a fixed point. The array of probabilities has zero entropy when the probability of each edge in the array is 0 or 1. The closed-loop

  12. Pairs Of Edges As Chords And As Cut-Edges

    Directory of Open Access Journals (Sweden)

    McKee Terry A.

    2014-11-01

    Full Text Available Several authors have studied the graphs for which every edge is a chord of a cycle; among 2-connected graphs, one characterization is that the deletion of one vertex never creates a cut-edge. Two new results: among 3-connected graphs with minimum degree at least 4, every two adjacent edges are chords of a common cycle if and only if deleting two vertices never creates two adjacent cut-edges; among 4-connected graphs, every two edges are always chords of a common cycle.

  13. Edge-on!

    Science.gov (United States)

    2007-08-01

    Peering at Uranus's Rings as they Swing Edge-on to Earth for the First Time Since their Discovery in 1977 As Uranus coasts through a brief window of time when its rings are edge-on to Earth - a view of the planet we get only once every 42 years - astronomers peering at the rings with ESO's Very Large Telescope and other space or ground-based telescopes are getting an unprecedented view of the fine dust in the system, free from the glare of the bright rocky rings. They may even find a new moon or two. ESO PR Photo 37/07 ESO PR Photo 37/07 The Uranus System "ESO's VLT took data at the precise moment when the rings were edge-on to Earth," said Imke de Pater, of University of California, Berkeley who coordinated the worldwide campaign. She worked with two team members observing in Chile: Daphne Stam of the Technical University Delft in the Netherlands and Markus Hartung of ESO. The observations were done with NACO, one of the adaptive optics instruments installed at the VLT. With adaptive optics, it is possible to obtain images almost free from the blurring effect of the atmosphere. It is as if the 8.2-m telescope were observing from space. Observations were also done with the Keck telescope in Hawaii, the Hubble Space Telescope, and at the Palomar Observatory. "Using different telescopes around the world allows us to observe as much of the changes during the ring-plane crossing as possible: when Uranus sets as seen from the VLT, it can still be observed by the Keck," emphasised Stam. Uranus orbits the Sun in 84 years. Twice during a Uranian year, the rings appear edge-on to Earth for a brief period. The rings were discovered in 1977, so this is the first time for a Uranus ring-crossing to be observed from Earth. The advantage of observations at a ring-plane crossing is that it becomes possible to look at the rings from the shadowed or dark side. From that vantage point, the normally bright outer rings grow fainter because their centimetre- to metre-sized rocks obscure

  14. Cheating on the edge.

    Directory of Open Access Journals (Sweden)

    Lee Alan Dugatkin

    2008-07-01

    Full Text Available We present the results of an individual agent-based model of antibiotic resistance in bacteria. Our model examines antibiotic resistance when two strategies exist: "producers"--who secrete a substance that breaks down antibiotics--and nonproducers ("cheats" who do not secrete, or carry the machinery associated with secretion. The model allows for populations of up to 10,000, in which bacteria are affected by their nearest neighbors, and we assume cheaters die when there are no producers in their neighborhood. Each of 10,000 slots on our grid (a torus could be occupied by a producer or a nonproducer, or could (temporarily be unoccupied. The most surprising and dramatic result we uncovered is that when producers and nonproducers coexist at equilibrium, nonproducers are almost always found on the edges of clusters of producers.

  15. Edge remap for solids

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Edge conduction in vacuum glazing

    Energy Technology Data Exchange (ETDEWEB)

    Simko, T.M.; Collins, R.E. [Sydney Univ., NSW (Australia). Dept. of Applied Physics; Beck, F.A.; Arasteh, D. [Lawrence Berkeley Lab., CA (United States)

    1995-03-01

    Vacuum glazing is a form of low-conductance double glazing using in internal vacuum between the two glass sheets to eliminate heat transport by gas conduction and convection. An array of small support pillars separates the sheets; fused solder glass forms the edge seal. Heat transfer through the glazing occurs by radiation across the vacuum gap, conduction through the support pillars, and conduction through the bonded edge seal. Edge conduction is problematic because it affects stresses in the edge region, leading to possible failure of the glazing; in addition, excessive heat transfer because of thermal bridging in the edge region can lower overall window thermal performance and decrease resistance to condensation. Infrared thermography was used to analyze the thermal performance of prototype vacuum glazings, and, for comparison, atmospheric pressure superwindows. Research focused on mitigating the edge effects of vacuum glazings through the use of insulating trim, recessed edges, and framing materials. Experimentally validated finite-element and finite-difference modeling tools were used for thermal analysis of prototype vacuum glazing units and complete windows. Experimental measurements of edge conduction using infrared imaging were found to be in good agreement with finite-element modeling results for a given set of conditions. Finite-element modeling validates an analytic model developed for edge conduction.

  17. Edge Bundling in Information Visualization

    National Research Council Canada - National Science Library

    Hong Zhou Panpan Xu Xiaoru Yuan Huamin Qu

    2013-01-01

    The edge, which can encode relational data in graphs and multidimensional data in parallel coordinates plots, is an important visual primitive for encoding data in information visualization research...

  18. Cutting Edge Localisation in an Edge Profile Milling Head

    NARCIS (Netherlands)

    Fernandez Robles, Laura; Azzopardi, George; Alegre, Enrique; Petkov, Nicolai

    2015-01-01

    Wear evaluation of cutting tools is a key issue for prolonging their lifetime and ensuring high quality of products. In this paper, we present a method for the effective localisation of cutting edges of inserts in digital images of an edge profile milling head. We introduce a new image data set of

  19. The Robotic Edge Finishing Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Edge instabilities of topological superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Johannes S. [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg (Germany); Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany); Assaad, Fakher F. [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg (Germany); Schnyder, Andreas P. [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany)

    2016-07-01

    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 and a diverging density of states. 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. Here, we employ Monte Carlo simulations combined with mean-field considerations to examine the instabilities of the flat-band edge states of d{sub xy}-wave superconductors. We find that attractive interactions induce a complex s-wave pairing instability together with a density wave instability. Repulsive interactions, on the other hand, lead to ferromagnetism mixed with spin-triplet pairing at the edge. We discuss the implications of our findings for experiments on cuprate high-temperature superconductors.

  1. Status and Verification of Edge Plasma Turbulence Code BOUT

    Energy Technology Data Exchange (ETDEWEB)

    Umansky, M V; Xu, X Q; Dudson, B; LoDestro, L L; Myra, J R

    2009-01-08

    The BOUT code is a detailed numerical model of tokamak edge turbulence based on collisional plasma uid equations. BOUT solves for time evolution of plasma uid variables: plasma density N{sub i}, parallel ion velocity V{sub {parallel}i}, electron temperature T{sub e}, ion temperature T{sub i}, electric potential {phi}, parallel current j{sub {parallel}}, and parallel vector potential A{sub {parallel}}, in realistic 3D divertor tokamak geometry. The current status of the code, physics model, algorithms, and implementation is described. Results of verification testing are presented along with illustrative applications to tokamak edge turbulence.

  2. Benchmarking Tokamak edge modelling codes

    Science.gov (United States)

    Contributors To The Efda-Jet Work Programme; Coster, D. P.; Bonnin, X.; Corrigan, G.; Kirnev, G. S.; Matthews, G.; Spence, J.; Contributors to the EFDA-JET work programme

    2005-03-01

    Tokamak edge modelling codes are in widespread use to interpret and understand existing experiments, and to make predictions for future machines. Little direct benchmarking has been done between the codes, and the users of the codes have tended to concentrate on different experimental machines. An important validation step is to compare the codes for identical scenarios. In this paper, two of the major edge codes, SOLPS (B2.5-Eirene) and EDGE2D-NIMBUS are benchmarked against each other. A set of boundary conditions, transport coefficients, etc. for a JET plasma were chosen, and the two codes were run on the same grid. Initially, large differences were seen in the resulting plasmas. These differences were traced to differing physics assumptions with respect to the parallel heat flux limits. Once these were switched off in SOLPS, or implemented and switched on in EDGE2D-NIMBUS, the remaining differences were small.

  3. Edge instabilities of topological superconductors

    Science.gov (United States)

    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.

  4. Domination Edge Lift Critical Trees | Desormeaux | Quaestiones ...

    African Journals Online (AJOL)

    stract. Let uxv be an induced path with center x in a graph G. The edge lifting of uv off x is defined as the action of removing edges ux and vx from the edge set of G, while adding the edge uv to the edge set of G. We study trees for which every possible edge lift changes the domination number. We show that there are no ...

  5. Imaging of Coulomb-Driven Quantum Hall Edge States

    KAUST Repository

    Lai, Keji

    2011-10-01

    The edges of a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime are divided into alternating metallic and insulating strips, with their widths determined by the energy gaps of the QHE states and the electrostatic Coulomb interaction. Local probing of these submicrometer features, however, is challenging due to the buried 2DEG structures. Using a newly developed microwave impedance microscope, we demonstrate the real-space conductivity mapping of the edge and bulk states. The sizes, positions, and field dependence of the edge strips around the sample perimeter agree quantitatively with the self-consistent electrostatic picture. The evolution of microwave images as a function of magnetic fields provides rich microscopic information around the ν=2 QHE state. © 2011 American Physical Society.

  6. Phase dynamics of edge transport bifurcation induced by external biasing

    Science.gov (United States)

    Li, B.; Wang, X. Y.; Xie, Z. J.; Li, P. F.; Gentle, K. W.

    2018-02-01

    Edge transport bifurcation induced by external biasing is explored with self-consistent turbulence simulations in a flux-driven system with both closed and open magnetic field lines. Without bias, the nonlinear evolution of interchange turbulence produces large-scale turbulent eddies, leading to the high levels of radial transport in the edge region. With sufficiently strong biasing, a strong suppression of turbulence is found. The plasma potential structures are strongly modified with the generation of sheared mean flows at the plasma edge. Consequently, the turbulence-driven flux is decreased to a much lower level, indicating a transition to a state of reduced transport. The simulations show that the dynamics of the phase and amplitude of fluctuations play a crucial role in the mechanism of transport suppression driven by biasing.

  7. On the edge: haptic discrimination of edge sharpness.

    Directory of Open Access Journals (Sweden)

    Andy L Skinner

    Full Text Available 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.

  8. Protected Edge Modes without Symmetry

    Directory of Open Access Journals (Sweden)

    Michael Levin

    2013-05-01

    Full Text Available We discuss the question of when a gapped two-dimensional electron system without any symmetry has a protected gapless edge mode. While it is well known that systems with a nonzero thermal Hall conductance, K_{H}≠0, support such modes, here we show that robust modes can also occur when K_{H}=0—if the system has quasiparticles with fractional statistics. We show that some types of fractional statistics are compatible with a gapped edge, while others are fundamentally incompatible. More generally, we give a criterion for when an electron system with Abelian statistics and K_{H}=0 can support a gapped edge: We show that a gapped edge is possible if and only if there exists a subset of quasiparticle types M such that (1 all the quasiparticles in M have trivial mutual statistics, and (2 every quasiparticle that is not in M has nontrivial mutual statistics with at least one quasiparticle in M. We derive this criterion using three different approaches: a microscopic analysis of the edge, a general argument based on braiding statistics, and finally a conformal field theory approach that uses constraints from modular invariance. We also discuss the analogous result for two-dimensional boson systems.

  9. The advanced smart grid edge power driving sustainability

    CERN Document Server

    Carvallo, Andres

    2011-01-01

    Placing emphasis on practical ""how-to"" guidance, this cutting-edge resource provides you with a first-hand, insider's perspective on the advent and evolution of smart grids in the 21st century (smart grid 1.0). You gain a thorough understanding of the building blocks that comprise basic smart grids, including power plant, transmission substation, distribution, and meter automation. Moreover, this forward-looking volume explores the next step of this technology's evolution. It provides a detailed explanation of how an advanced smart grid incorporates demand response with smart appliances and

  10. Quantum Beats of Resonant Tunneling between Fractional Quantum Hall Edges

    Science.gov (United States)

    Maasilta, Ilari J.; Goldman, V. J.

    1997-03-01

    We report measurements of resonant tunneling between two fractional quantum Hall edges in a quantum antidot geometry (I. J. Maasilta and V. J. Goldman, to appear in Phys. Rev. B 55),(1997).. We observe beats in the conductance oscillations, whose evolution as a function of experimental parameters is discussed. Possible explanations in terms of different models (G. Kirczenow Phys. Rev. B 53), 15767 (1996), M. Geller et. al, preprint. are presented.

  11. All-graphene edge contacts

    DEFF Research Database (Denmark)

    Jacobsen, Kåre Wedel; Falkenberg, Jesper Toft; Papior, Nick Rübner

    2016-01-01

    Using ab-initio methods we investigate the possibility of three-terminalgraphene "T-junction" devices and show that these all-graphene edge contactsare energetically feasible when the 1D interface itself is free from foreignatoms. We examine the energetics of various junction structures as a func......Using ab-initio methods we investigate the possibility of three-terminalgraphene "T-junction" devices and show that these all-graphene edge contactsare energetically feasible when the 1D interface itself is free from foreignatoms. We examine the energetics of various junction structures...... to be in therange of 1-10 kΩμm which is comparable to the best contact resistance reportedfor edge-contacted graphene-metal contacts. We conclude that conductingall-carbon T-junctions should be feasible....

  12. Finding edges in noisy scenes

    Science.gov (United States)

    Machuca, R.; Gilbert, A. L.

    1981-01-01

    Edge detection in the presence of noise is a well-known problem. This paper examines an applications-motivated approach for solving the problem using novel techniques and presents a method developed by the authors that performs well on a large class of targets. ROC curves are used to compare this method with other well-known edge detection operators, with favorable results. A theoretical argument is presented that favors LMMSE filtering over median filtering in extremely noisy scenes. Simulated results of the research are presented.

  13. Edge enhanced morphology for infrared image analysis

    Science.gov (United States)

    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.

  14. Topological edge states on time-periodically strained armchair graphene nanoribbons

    Science.gov (United States)

    Roman-Taboada, Pedro; Naumis, Gerardo G.

    2017-10-01

    We report the emergence of electronic edge states in time-periodically driven strained armchair terminated graphene nanoribbons. This is done by considering a short-pulse spatial-periodic strain field. Then, the tight-binding Hamiltonian of the system is mapped into a one-dimensional ladder. The time periodicity is considered within the Floquet formalism. Thus the quasienergy spectrum is found numerically by diagonalizing the evolution operator. For some particular cases, the quasienergy spectrum is found analytically. We found that the system is able to support gapless and gapped phases. Very different edge states emerge for both the gapless and the gapful phases. In the case of the gapped phase, edge states emerge at the gap centered at zero quasienergy, although the Chern number is zero due to the chiral symmetry of the system. For the gapless phase, besides edge states at zero quasienergy, cosinelike edge states which merge and coexist with the bulk band are observed. To confirm the topological nature of these edge states, we analytically obtained the effective Hamiltonian and its spectrum for a particular case, finding that the edge states are topologically weak. Finally, we found analytically the evolution of band edges and their crossings as a function of the driven period. Topological modes arise at such crossings.

  15. Diffraction at a Straight Edge

    Indian Academy of Sciences (India)

    IAS Admin

    teaching and understanding physics. The simplest problem in diffraction – light pass- ing a straight edge – did not receive a rigorous solution till Sommerfeld's .... the English and. French nations. Around the same time, Young in England gave a dif- ferent formulation in which the original wave falling on the screen travels ...

  16. Morpho (?) phono (?) logical fuzzy edges

    African Journals Online (AJOL)

    Open Access DOWNLOAD FULL TEXT Subscription or Fee Access. Morpho (?) phono (?) logical fuzzy edges: The case of {-/}/{-/U/} semantic (?) contrast in Shona. K. G. Mkangwanwi. Abstract. (ZAMBEZIA: Journal of Humanities of the Univ of Zimbabwe, 2000 27(1): 47-54). Full Text: EMAIL FULL TEXT EMAIL FULL TEXT

  17. On the Edge of Existence

    DEFF Research Database (Denmark)

    Richter, Line

    2016-01-01

    Based on ethnographic fieldwork among Malian migrants and migration brokers in Mali, Algeria, Morocco, and France, this article investigates life in exile on the edge of Europe. Zooming in on the experiences of interlocutors in Morocco and Algeria, the article will explore the experiential...

  18. A Catalog of Edge-on Disk Galaxies: From Galaxies with a Bulge to Superthin Galaxies

    OpenAIRE

    Kautsch, S. J.; Grebel, E. K.; Barazza, F. D.; Gallagher, J. S.

    2005-01-01

    The formation and evolution of disk-dominated galaxies is difficult to explain, yet these objects exist. We therefore embarked on a study aimed at a better understanding of these enigmatic objects. We used data from the SDSS DR1 in order to identify edge-on galaxies with disks in a uniform, reproducible, automated fashion. We identified 3169 edge-on disk galaxies, which we subdivided into disk galaxies with bulge, intermediate types, and simple disk galaxies without any obvious bulge componen...

  19. Edge imaging in intense beams

    Directory of Open Access Journals (Sweden)

    S. Bernal

    2002-06-01

    Full Text Available The appearance of rings of charge observed near the edge of beams from high-perveance guns is described with a simple ray tracing technique inspired by the particle-core model. We illustrate the technique, which has no analog in light optics, with examples from experiments employing solenoid focusing of an electron beam. The rings of charge result from the combined effects of external focusing and space-charge forces acting on paraxial fringe particles with relatively large initial transverse velocities. The model is independent of the physical mechanisms responsible for the fringe particles. Furthermore, the focal length for edge imaging in a uniform focusing channel is derived using a linearized trajectory equation for the motion of fringe particles. Counterintuitively, the focal length decreases as the beam current increases.

  20. Scattering by an axisymmetric edge

    Science.gov (United States)

    Kaloshin, V. A.; Popov, A. P.

    1984-08-01

    A method of physical theory of diffraction (PTD) in an axisymmetric problem is used to obtain the first two terms of the uniform asymptotics of the radiation pattern of an edge wave with respect to inverse semiinteger powers of the wavenumber expressed through a two-term uniform asymptotics of the corresponding two-dimensional problem. As examples, calculations are made of: (1) the uniform asymptotics of the correction refining the Kirchhoff approximation for the radiation pattern of an axisymmetric reflector antenna; and (2) the asymptotics of the radiation pattern of symmetric modes from the open end of a circular flanged waveguide. An improvement of the PTD method is proposed for calculating the second term of the uniform asymptotics of an edge wave with respect to inverse powers of the wavenumber; the example of the diffraction of a toroidal wave by a bicone is considered.

  1. Edge Simulation Laboratory Project Report

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, R. H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dorf, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dorr, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rognlien, T. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2011-02-25

    In 2010 The Edge Simulation Laboratory (ESL) embarked upon the plan laid out in the renewal proposal submitted in December 2009. This proposal called for initially parallel efforts addressing the physics of the closed-flux-surface pedestal region, using existing computational tools (GYRO, BOUT++) and analytic modeling, and physics of the scrape-off layer via development of the new edge gyrokinetic code COGENT. Progress in the former area is described in a series of monthly progress reports prepared by General Atomics; these are attached as a set of appendices (describing work done in the month prior to the indicated date). Progress in the latter area, as well as associated theoretical development, is described.

  2. Red-edge position of habitable exoplanets around M-dwarfs

    OpenAIRE

    Takizawa, Kenji; Minagawa, Jun; Tamura, Motohide; Kusakabe, Nobuhiko; Narita, Norio

    2017-01-01

    One of the possible signs of life on distant habitable exoplanets is the red-edge, which is a rise in the reflectivity of planets between visible and near-infrared (NIR) wavelengths. Previous studies suggested the possibility that the red-edge position for habitable exoplanets around M-dwarfs may be shifted to a longer wavelength than that for Earth. We investigated plausible red-edge position in terms of the light environment during the course of the evolution of phototrophs. We show that ph...

  3. Environmental Dataset Gateway (EDG) REST Interface

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  4. Evaluation of edge detectors using average risk

    NARCIS (Netherlands)

    Spreeuwers, Lieuwe Jan; van der Heijden, Ferdinand

    1992-01-01

    A new method for evaluation of edge detectors, based on the average risk of a decision, is discussed. The average risk is a performance measure well-known in Bayesian decision theory. Since edge detection can be regarded as a compound decision making process, the performance of an edge detector is

  5. Edge Transfer Lithography Using Alkanethiol Inks

    NARCIS (Netherlands)

    Sharpe, R.B.A.; Titulaer, Bram J.F.; Peeters, Emiel; Burdinski, Dirk; Huskens, Jurriaan; Zandvliet, Henricus J.W.; Reinhoudt, David; Poelsema, Bene

    2006-01-01

    Edge lithographic patterning techniques are based on the utilization of the edges of micrometer-sized template features for the reproduction of submicrometer structures. Edge transfer lithography (ETL) permits local surface modification in a single step by depositing self-assembled monolayers onto a

  6. Acyclicity in edge-colored graphs

    DEFF Research Database (Denmark)

    Gutin, Gregory; Jones, Mark; Sheng, Bin

    2017-01-01

    A walk W in edge-colored graphs is called properly colored (PC) if every pair of consecutive edges in W is of different color. We introduce and study five types of PC acyclicity in edge-colored graphs such that graphs of PC acyclicity of type i is a proper superset of graphs of acyclicity of type...

  7. Hidden edge Dirac point and robust quantum edge transport in InAs/GaSb quantum wells

    Science.gov (United States)

    Li, Chang-An; Zhang, Song-Bo; Shen, Shun-Qing

    2018-01-01

    The robustness of quantum edge transport in InAs/GaSb quantum wells in the presence of magnetic fields raises an issue on the fate of topological phases of matter under time-reversal symmetry breaking. A peculiar band structure evolution in InAs/GaSb quantum wells is revealed: the electron subbands cross the heavy hole subbands but anticross the light hole subbands. The topologically protected band crossing point (Dirac point) of the helical edge states is pulled to be close to and even buried in the bulk valence bands when the system is in a deeply inverted regime, which is attributed to the existence of the light hole subbands. A sizable Zeeman energy gap verified by the effective g factors of edge states opens at the Dirac point by an in-plane or perpendicular magnetic field; however, it can also be hidden in the bulk valance bands. This provides a plausible explanation for the recent observation on the robustness of quantum edge transport in InAs/GaSb quantum wells subjected to strong magnetic fields.

  8. Edge wrinkling of a soft ridge with gradient thickness

    Science.gov (United States)

    Zhao, Yan; Shao, Zhi-Chun; Li, Guo-Yang; Zheng, Yang; Zhang, Wan-Yu; Li, Bo; Cao, Yanping; Feng, Xi-Qiao

    2017-06-01

    We investigate the edge wrinkling of a soft ridge with gradient thickness under axial compression. Our experiments show that the wrinkling wavelength undergoes a considerable increase with increasing load. Simple scaling laws are derived based on an upper-bound analysis to predict the critical buckling conditions and the evolution of wrinkling wavelength during the post-buckling stage, and the results show good accordance with our finite element simulations and experiments. We also report a pattern transformation triggered by the edge wrinkling of soft ridge arrays. The results and method not only help understand the correlation between the growth and form observed in some natural systems but also inspire a strategy to fabricate advanced functional surfaces.

  9. Towards intrinsic magnetism of graphene sheets with irregular zigzag edges.

    Science.gov (United States)

    Chen, Lianlian; Guo, Liwei; Li, Zhilin; Zhang, Han; Lin, Jingjing; Huang, Jiao; Jin, Shifeng; Chen, Xiaolong

    2013-01-01

    The magnetism of graphene has remained divergent and controversial due to absence of reliable experimental results. Here we show the intrinsic magnetism of graphene edge states revealed based on unidirectional aligned graphene sheets derived from completely carbonized SiC crystals. It is found that ferromagnetism, antiferromagnetism and diamagnetism along with a probable superconductivity exist in the graphene with irregular zigzag edges. A phase diagram is constructed to show the evolution of the magnetism. The ferromagnetic ordering curie-temperature of the fundamental magnetic order unit (FMOU) is 820 ± 80 K. The antiferromagnetic ordering Neel temperature of the FMOUs belonging to different sublattices is about 54 ± 2 K. The diamagnetism is similar to that of graphite and can be well described by the Kotosonov's equation. Our experimental results provide new evidences to clarify the controversial experimental phenomena observed in graphene and contribute to a deeper insight into the nature of magnetism in graphene based system.

  10. Instant Adobe Edge Inspect starter

    CERN Document Server

    Khan, Joseph

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. This easy-to-understand Starter guide will get you up to speed with Adobe Edge Inspect quickly and with little effort.This book is for frontend web developers and designers who are developing and testing web applications targeted for mobile browsers. It's assumed that you have a basic understanding of creating web applications using HTML, CSS, and JavaScript, as well as being familiar with running web pages from local HTTP servers. Readers are a

  11. How Forest Inhomogeneities Affect the Edge Flow

    DEFF Research Database (Denmark)

    Boudreault, Louis-Étienne; Dupont, Sylvain; Bechmann, Andreas

    2016-01-01

    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...

  12. Reflections on the knife edge.

    Science.gov (United States)

    Murphy, John Patrick Michael; Chabner, Bruce A

    2011-01-01

    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.

  13. A continuum theory of edge dislocations

    Science.gov (United States)

    Berdichevsky, V. L.

    2017-09-01

    dislocation phase space is strikingly simple. Dislocation phase space is split in a family of subspaces corresponding to constant values of dislocation polarizations; in each equipolarization subspace there are many local minima of energy; for zero external stresses the system is stuck in a local minimum of energy; for non-zero slowly changing external stress, dislocation polarization evolves, while the system moves over local energy minima of equipolarization subspaces. Such a simple picture of dislocation dynamics is due to the presence of two time scales, slow evolution of dislocation polarization and fast motion of the system over local minima of energy. The existence of two time scales is justified for a neutral system of edge dislocations.

  14. Background Modelling Using Edge-Segment Distributions

    Directory of Open Access Journals (Sweden)

    Jaemyun Kim

    2013-02-01

    Full Text Available We propose an edge-segment-based statistical background modelling algorithm to detect the moving edges for the detection of moving objects using a static camera. Traditional pixel intensity-based background modelling algorithms face difficulties in dynamic environments since they cannot handle sudden changes in illumination. They also bring out ghosts when a sudden change occurs in the scene. To cope with this issue, intensity and noise robust edge-based features have emerged. However, existing edge-pixel-based methods suffer from scattered moving edge pixels since they cannot utilize the shape. Moreover, traditional segment-based methods cannot handle edge shape variations and miss moving edges when they come close to the background edges. Unlike traditional approaches, our proposed method builds the background model from ordinary training frames that may contain moving objects. Furthermore, it does not leave any ghosts behind. Moreover, our method uses an automatic threshold for every background edge distribution for matching. This makes our approach robust to illumination change, camera movement and background motion. Experiments show that our method outperforms others and can detect moving edges efficiently despite the above mentioned difficulties.

  15. Imaging edges of nanostructured graphene

    DEFF Research Database (Denmark)

    Kling, Jens; Cagliani, Alberto; Booth, T. J.

    Graphene, as the forefather of 2D-materials, attracts much attention due to its extraordinary properties like transparency, flexibility and outstanding high conductivity, together with a thickness of only one atom. However, graphene also possesses no band gap, which makes it unsuitable for many...... electronic applications like transistors. It has been shown theoretically that by nanostructuring pristine graphene, e.g. with regular holes, the electronic properties can be tuned and a band gap introduced. The size, distance and edge termination of these “defects” influence the adaptability....... Such nanostructuring can be done experimentally, but especially characterization at atomic level is a huge challenge. High-resolution TEM (HRTEM) is used to characterize the atomic structure of graphene. We optimized the imaging conditions used for the FEI Titan ETEM. To reduce the knock-on damage of the carbon atoms...

  16. At the edge of intonation

    DEFF Research Database (Denmark)

    Niebuhr, Oliver

    2012-01-01

    The paper is concerned with the 'edge of intonation' in a twofold sense. It focuses on utterance-final F0 movements and crosses the traditional segment-prosody divide by investigating the interplay of F0 and voiceless fricatives in speech production. An experiment was performed for German with four...... types of voiceless fricatives: /f/, /s/, /ʃ/ and /x/. They were elicited with scripted dialogues in the contexts of terminal falling statement and high rising question intonations. Acoustic analyses show that fricatives concluding the high rising question intonations had higher mean centres of gravity...... (CoGs), larger CoG ranges and higher noise energy levels than fricatives concluding the terminal falling statement intonations. The different spectral-energy patterns are suitable to induce percepts of a high 'aperiodic pitch' at the end of the questions and of a low 'aperiodic pitch' at the end...

  17. Object detection using categorised 3D edges

    DEFF Research Database (Denmark)

    Kiforenko, Lilita; Buch, Anders Glent; Bodenhagen, Leon

    2015-01-01

    is made possible by the explicit use of edge categories in the feature descriptor. We quantitatively compare our approach with the state-of-the-art template based Linemod method, which also provides an effective way of dealing with texture-less objects, tests were performed on our own object dataset. Our......In this paper we present an object detection method that uses edge categorisation in combination with a local multi-modal histogram descriptor, all based on RGB-D data. Our target application is robust detection and pose estimation of known objects. We propose to apply a recently introduced edge...... categorisation algorithm for describing objects in terms of its different edge types. Relying on edge information allow our system to deal with objects with little or no texture or surface variation. We show that edge categorisation improves matching performance due to the higher level of discrimination, which...

  18. Magnetic signature of current carrying edge localized modes filaments on the Joint European Torus tokamak

    DEFF Research Database (Denmark)

    Migliucci, P.; Naulin, Volker

    2010-01-01

    Fast magnetic pickup coils are used in forward modeling to match parameters in a simple edge localized mode (ELM) filament model. This novel method allows us to determine key parameters for the evolution of the ELM filaments, as effective mode number, radial and toroidal velocities, and average...

  19. Selective Electroless Silver Deposition on Graphene Edges

    DEFF Research Database (Denmark)

    Durhuus, D.; Larsen, M. V.; Andryieuski, Andrei

    2015-01-01

    We demonstrate a method of electroless selective silver deposition on graphene edges or between graphene islands without covering the surface of graphene. Modifications of the deposition recipe allow for decoration of graphene edges with silver nanoparticles or filling holes in damaged graphene...... on silica substrate and thus potentially restoring electric connectivity with minimal influence on the overall graphene electrical and optical properties. The presented technique could find applications in graphene based transparent conductors as well as selective edge functionalization and can be extended...

  20. Topological edge states of bound photon pairs

    Science.gov (United States)

    Gorlach, Maxim A.; Poddubny, Alexander N.

    2017-05-01

    We predict the existence of interaction-driven edge states of bound two-photon quasiparticles in a dimer periodic array of nonlinear optical cavities. The energy spectrum of photon pairs is dramatically richer than in the noninteracting case or in a simple lattice, featuring collapse and revival of multiple edge and bulk modes as well as edge states in continuum. We link the edge-state existence to the two-photon quantum walk graph connectivity. Our results offer a route to control quantum entanglement and provide insights into the physics of many-body topological states.

  1. Chiral edge fluctuations of colloidal membranes

    Science.gov (United States)

    Jia, Leroy; Zakhary, Mark; Dogic, Zvonimir; Pelcovits, Robert; Powers, Thomas

    Using experiments and theory we study chiral fluctuations of the edge of a nearly flat colloidal membrane, consisting of rod-like viruses held together by the depletion interaction. Our measurements show an anomalous peak in the power spectrum around 1 inverse micron. Using an effective theory to describe the liquid crystal degrees of freedom by geometric properties of the edge, such as length, geodesic torsion, and curvature, we calculate the spectrum of out-of-plane edge fluctuations. The peak arises for sufficiently strong chirality, and corresponds to the instability of a flat membrane to a shape with helical, rippled edges.

  2. Selective edge enhancement using anisotropic vortex filter.

    Science.gov (United States)

    Sharma, Manoj Kumar; Joseph, Joby; Senthilkumaran, Paramasivam

    2011-09-20

    In optical image processing, selective edge enhancement is important when it is preferable to emphasize some edges of an object more than others. We propose a new method for selective edge enhancement of amplitude objects using the anisotropic vortex phase mask by introducing anisotropy in a conventional vortex mask with the help of the sine function. The anisotropy is capable of edge enhancement in the selective region and in the required direction by changing the power and offset angle, respectively, of the sine function.

  3. Edge passivation induced single-edge ferromagnetism of zigzag MoS{sub 2} nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rui; Sun, Hui; Ma, Ben; Hu, Jingguo, E-mail: jghu@yzu.edu.cn; Pan, Jing, E-mail: panjing_yz@163.com

    2017-01-30

    We performed density functional theory study on electronic structure, magnetic properties and stability of zigzag MoS{sub 2} nanoribbons (ZMoS{sub 2}NRs) with and without oxygen (O) passivation. The bare ZMoS{sub 2}NRs are magnetic metal with ferromagnetic edge states, edge passivation decreases their magnetism because of the decrease of edge unsaturated electrons. Obviously, the electronic structure and magnetic properties of ZMoS{sub 2}NRs greatly depend on edge states. When both edges are passivated by O atoms, ZMoS{sub 2}NRs are nonmagnetic metals. When either edge is passivated by O atoms, the systems exhibit single-edge ferromagnetism and magnetism concentrates on the non-passivated edge. Edge passivation can not only tune the magnetism of ZMoS{sub 2}NRs, but also enhance their stability by eliminating dangling bonds. These interesting findings on ZMoS{sub 2}NRs may open the possibility of their application in nanodevices and spintronics. - Highlights: • Edge passivation for tuning magnetism of zigzag MoS{sub 2} nanoribbons (ZMoS{sub 2}NRs) is proposed. • Edge passivation can tune ZMoS{sub 2}NRs from nonmagnetic metal to ferromagnetic metal. • When either edge is passivated, the systems exhibit single-edge ferromagnetic states. • These findings may inspire great interest in the community of ZMoS{sub 2}NRs and motivate numerous experimental researches.

  4. Leading-edge vortex burst on a low-aspect-ratio rotating flat plate

    Science.gov (United States)

    Medina, Albert; Jones, Anya R.

    2016-08-01

    This study experimentally investigates the phenomenon of leading-edge-vortex burst on rotating flat plate wings. An aspect-ratio-2 wing was driven in pure rotation at a Reynolds number of Re=2500 . Of primary interest is the evolution of the leading-edge vortex along the wing span over a single-revolution wing stroke. Direct force measurements of the lift produced by the wing revealed a single global lift maximum relatively early in the wing stroke. Stereoscopic particle image velocimetry was applied to several chordwise planes to quantify the structure and strength of the leading-edge vortex and its effect on lift production. This analysis revealed opposite-sign vorticity entrainment into the core of the leading-edge vortex, originating from a layer of secondary vorticity along the wing surface. Coincident with the lift peak, there emerged both a concentration of opposite vorticity in the leading-edge-vortex core, as well as axial flow stagnation within the leading-edge-vortex core. Planar control volume analysis was performed at the midspan to quantify the contributions of vorticity transport mechanisms to the leading-edge-vortex circulation. The rate of circulation annihilation by opposite-signed vorticity entrainment was found to be minimal during peak lift production, where convection balanced the flux of vorticity resulting in stagnation and eventually reversal of axial flow. Finally, vortex burst was found to be correlated with swirl number, where bursting occurs at a swirl threshold of Sw<0.6 .

  5. Signed Total Roman Edge Domination In Graphs

    Directory of Open Access Journals (Sweden)

    Asgharsharghi Leila

    2017-11-01

    Full Text Available Let G = (V,E be a simple graph with vertex set V and edge set E. A signed total Roman edge dominating function of G is a function f : Ʃ → {−1, 1, 2} satisfying the conditions that (i Ʃe′∈N(e f(e′ ≥ 1 for each e ∈ E, where N(e is the open neighborhood of e, and (ii every edge e for which f(e = −1 is adjacent to at least one edge e′ for which f(e′ = 2. The weight of a signed total Roman edge dominating function f is !(f = Ʃe∈E f(e. The signed total Roman edge domination number y′stR(G of G is the minimum weight of a signed total Roman edge dominating function of G. In this paper, we first prove that for every tree T of order n ≥ 4, y′stR(T ≥ 17−2n/5 and we characterize all extreme trees, and then we present some sharp bounds for the signed total Roman edge domination number. We also determine this parameter for some classes of graphs.

  6. Connected domination stable graphs upon edge addition ...

    African Journals Online (AJOL)

    A set S of vertices in a graph G is a connected dominating set of G if S dominates G and the subgraph induced by S is connected. We study the graphs for which adding any edge does not change the connected domination number. Keywords: Connected domination, connected domination stable, edge addition ...

  7. Automatic Edging and Trimming of Hardwood Lumber

    Science.gov (United States)

    D. Earl Kline; Eugene M. Wengert; Philip A. Araman

    1990-01-01

    Studies have shown that there is a potential to increase hardwood lumber value by more than 20 percent through optimum edging and trimming. Even a small portion of this percentage can boost the profitability of hardwood lumber manufacturers substantially. The objective of this research project is to develop an automated system which would assist in correct edging and...

  8. Leading edge gypsy moth population dynamics

    Science.gov (United States)

    M. R. Carter; F. W. Ravlin; M. L. McManus

    1991-01-01

    Leading edge gypsy moth populations have been the focus of several intervention programs (MDIPM, AIPM). Knowledge of gypsy moth population dynamics in leading edge area is crucial for effective management. Populations in these areas tend to reach outbreak levels (noticeable defoliation) within three to four years after egg masses are first detected. Pheromone traps...

  9. An overview of JET edge modelling activities

    Energy Technology Data Exchange (ETDEWEB)

    Coster, D.P. E-mail: david.coster@ipp.mpg.de; Bonnin, X.; Corrigan, G.; Dejarnac, R.; Fenstermacher, M.; Fundamenski, W.; Geier, A.; Hogan, J.; Kallenbach, A.; Kirschner, A.; Krieger, K.; Loarte, A.; Matthews, G.; Pitts, R.A.; Porter, G.; Pugno, R.; Reiser, D.; Reiter, D.; Sipila, S.; Spence, J.; Stangeby, P.C.; Tsitrone, E.; Tskhakaya, D.; Wischmeier, M

    2003-03-01

    A number of codes are in use at JET to model the edge plasma. The range of edge codes is described as is the range of physics issues being explored by these codes. The balance between focussed modelling (that looking at particular physics effects) and integrated modelling (attempting to combine codes or encapsulate the physics from some codes into other codes) is examined.

  10. Strong List Edge Coloring of Subcubic Graphs

    Directory of Open Access Journals (Sweden)

    Hongping Ma

    2013-01-01

    Full Text Available We study strong list edge coloring of subcubic graphs, and we prove that every subcubic graph with maximum average degree less than 15/7, 27/11, 13/5, and 36/13 can be strongly list edge colored with six, seven, eight, and nine colors, respectively.

  11. LES tests on airfoil trailing edge serration

    DEFF Research Database (Denmark)

    Zhu, Wei Jun; Shen, Wen Zhong

    2016-01-01

    In the present study, a large number of acoustic simulations are carried out for a low noise airfoil with different Trailing Edge Serrations (TES). The Ffowcs Williams-Hawkings (FWH) acoustic analogy is used for noise prediction at trailing edge. The acoustic solver is running on the platform...

  12. How Forest Inhomogeneities Affect the Edge Flow

    Science.gov (United States)

    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.

  13. Edge effects on water droplet condensation.

    Science.gov (United States)

    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. Partnership for Edge Physics Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kritz, Arnold H. [Lehigh Univ., Bethlehem, PA (United States). Dept. of Physics; Rafiq, Tariq [Lehigh Univ., Bethlehem, PA (United States). Dept. of Physics

    2017-07-31

    A major goal of our participation in the Edge Physics Simulation project has been to contribute to the understanding of the self-organization of tokamak turbulence fluctuations resulting in the formation of a staircase structure in the ion temperature. A second important goal is to demonstrate how small scale turbulence in plasmas self-organizes with dynamically driven quasi-stationary flow shear. These goals have been accomplished through the analyses of the statistical properties of XGC1 flux driven Gyrokinetic electrostatic ion temperature gradient (ITG) turbulence simulation data in which neutrals are included. The ITG turbulence data, and in particular fluctuation data, were obtained from a massively parallel flux-driven gyrokinetic full-f particle-in-cell simulation of a DIII-D like equilibrium. Below some the findings are summarized. It was observed that the emergence of staircase structure is related to the variations in the normalized temperature gradient length (R/LT) and the poloidal flow shear. Average turbulence intensity is found to be large in the vicinity of minima in R/LTi, where ITG growth is expected to be lower. The distributions of the occurrences of potential fluctuation are found to be Gaussian away from the staircase-step locations, but they are found to be non-Gaussian in the vicinity of staircase-step locations. The results of analytically derived expressions for the distribution of the occurrences of turbulence intensity and intensity flux were compared with the corresponding quantities computed using XGC1 simulation data and good agreement is found. The derived expressions predicts inward and outward propagation of turbulence intensity flux in an intermittent fashion. The outward propagation of turbulence intensity flux occurs at staircase-step locations and is related to the change in poloidal flow velocity shear and to the change in the ion temperature gradient. The standard deviation, skewness and kurtosis for turbulence quantities

  15. Localized Edge Vibrations and Edge Reconstruction by Joule Heating in Graphene Nanostructures

    DEFF Research Database (Denmark)

    Engelund, Mads; Fürst, Joachim Alexander; Jauho, Antti-Pekka

    2010-01-01

    Control of the edge topology of graphene nanostructures is critical to graphene-based electronics. A means of producing atomically smooth zigzag edges using electronic current has recently been demonstrated in experiments [Jia et al., Science 323, 1701 (2009)]. We develop a microscopic theory...... for current-induced edge reconstruction using density functional theory. Our calculations provide evidence for localized vibrations at edge interfaces involving unpassivated armchair edges. We demonstrate that these vibrations couple to the current, estimate their excitation by Joule heating, and argue...

  16. Red-edge position of habitable exoplanets around M-dwarfs.

    Science.gov (United States)

    Takizawa, Kenji; Minagawa, Jun; Tamura, Motohide; Kusakabe, Nobuhiko; Narita, Norio

    2017-08-08

    One of the possible signs of life on distant habitable exoplanets is the red-edge, which is a rise in the reflectivity of planets between visible and near-infrared (NIR) wavelengths. Previous studies suggested the possibility that the red-edge position for habitable exoplanets around M-dwarfs may be shifted to a longer wavelength than that for Earth. We investigated plausible red-edge position in terms of the light environment during the course of the evolution of phototrophs. We show that phototrophs on M-dwarf habitable exoplanets may use visible light when they first evolve in the ocean and when they first colonize the land. The adaptive evolution of oxygenic photosynthesis may eventually also use NIR radiation, by one of two photochemical reaction centers, with the other center continuing to use visible light. These "two-color" reaction centers can absorb more photons, but they will encounter difficulty in adapting to drastically changing light conditions at the boundary between land and water. NIR photosynthesis can be more productive on land, though its evolution would be preceded by the Earth-type vegetation. Thus, the red-edge position caused by photosynthetic organisms on habitable M-dwarf exoplanets could initially be similar to that on Earth and later move to a longer wavelength.

  17. Edge-functionalization of armchair graphene nanoribbons with pentagonal-hexagonal edge structures

    Science.gov (United States)

    Ryou, Junga; Park, Jinwoo; Kim, Gunn; Hong, Suklyun

    2017-06-01

    Using density functional theory calculations, we have studied the edge-functionalization of armchair graphene nanoribbons (AGNRs) with pentagonal-hexagonal edge structures. While the AGNRs with pentagonal-hexagonal edge structures (labeled (5,6)-AGNRs) are metallic, the edge-functionalized (5,6)-AGNRs with substitutional atoms opens a band gap. We find that the band structures of edge-functionalized (5,6)-N-AGNRs by substitution resemble those of defect-free (N-1)-AGNR at the Γ point, whereas those at the X point show the original ones of the defect-free N-AGNR. The overall electronic structures of edge-functionalized (5,6)-AGNRs depend on the number of electrons, supplied by substitutional atoms, at the edges of functionalized (5,6)-AGNRs.

  18. CFAR Edge Detector for Polarimetric SAR Images

    DEFF Research Database (Denmark)

    Schou, Jesper; Skriver, Henning; Nielsen, Allan Aasbjerg

    2003-01-01

    Finding the edges between different regions in an image is one of the fundamental steps of image analysis, and several edge detectors suitable for the special statistics of synthetic aperture radar (SAR) intensity images have previously been developed. In this paper, a new edge detector for polar......Finding the edges between different regions in an image is one of the fundamental steps of image analysis, and several edge detectors suitable for the special statistics of synthetic aperture radar (SAR) intensity images have previously been developed. In this paper, a new edge detector...... for polarimetric SAR images is presented using a newly developed test statistic in the complex Wishart distribution to test for equality of covariance matrices. The new edge detector can be applied to a wide range of SAR data from single-channel intensity data to multifrequency and/or multitemporal polarimetric...... SAR data. By simply changing the parameters characterizing the test statistic according to the applied SAR data, constant false-alarm rate detection is always obtained. An adaptive filtering scheme is presented, and the distributions of the detector are verified using simulated polarimetric SAR images...

  19. AliEn - EDG Interoperability in ALICE

    CERN Document Server

    Bagnasco, S; Buncic, P; Carminati, F; Cerello, P G; Saiz, P

    2003-01-01

    AliEn (ALICE Environment) is a GRID-like system for large scale job submission and distributed data management developed and used in the context of ALICE, the CERN LHC heavy-ion experiment. With the aim of exploiting upcoming Grid resources to run AliEn-managed jobs and store the produced data, the problem of AliEn-EDG interoperability was addressed and an in-terface was designed. One or more EDG (European Data Grid) User Interface machines run the AliEn software suite (Cluster Monitor, Storage Element and Computing Element), and act as interface nodes between the systems. An EDG Resource Broker is seen by the AliEn server as a single Computing Element, while the EDG storage is seen by AliEn as a single, large Storage Element; files produced in EDG sites are registered in both the EDG Replica Catalogue and in the AliEn Data Catalogue, thus ensuring accessibility from both worlds. In fact, both registrations are required: the AliEn one is used for the data management, the EDG one to guarantee the integrity and...

  20. Edge-Disjoint Fibonacci Trees in Hypercube

    Directory of Open Access Journals (Sweden)

    Indhumathi Raman

    2014-01-01

    Full Text Available The Fibonacci tree is a rooted binary tree whose number of vertices admit a recursive definition similar to the Fibonacci numbers. In this paper, we prove that a hypercube of dimension h admits two edge-disjoint Fibonacci trees of height h, two edge-disjoint Fibonacci trees of height h-2, two edge-disjoint Fibonacci trees of height h-4 and so on, as subgraphs. The result shows that an algorithm with Fibonacci trees as underlying data structure can be implemented concurrently on a hypercube network with no communication latency.

  1. Natural and artificial spectral edges in exoplanets

    Science.gov (United States)

    Lingam, Manasvi; Loeb, Abraham

    2017-09-01

    Technological civilizations may rely upon large-scale photovoltaic arrays to harness energy from their host star. Photovoltaic materials, such as silicon, possess distinctive spectral features, including an 'artificial edge' that is characteristically shifted in wavelength shortwards of the 'red edge' of vegetation. Future observations of reflected light from exoplanets would be able to detect both natural and artificial edges photometrically, if a significant fraction of the planet's surface is covered by vegetation or photovoltaic arrays, respectively. The stellar energy thus tapped can be utilized for terraforming activities by transferring heat and light from the day side to the night side on tidally locked exoplanets, thereby producing detectable artefacts.

  2. Adobe Edge Animate CC for dummies

    CERN Document Server

    Rohde, Michael

    2013-01-01

    The easy way to build HTML5 mobile and web apps using Adobe's new Edge Animate CC Edge Animate CC is an approachable WYSIWYG alternative for leveraging the power of languages like HTML5, CSS3, and JavaScript to design and develop for the web and mobile devices, even if you have no programming experience. Written by Michael Rohde, the book calls on this seasoned web developer's wealth of experience using Edge Animate CC, and a companion website includes all code from the book to help you apply what you learn as you go. Features an easy-to-use interface, with a propert

  3. Edge energies and shapes of nanoprecipitates.

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, John C.

    2006-01-01

    In this report we present a model to explain the size-dependent shapes of lead nano-precipitates in aluminum. Size-dependent shape transitions, frequently observed at nanolength scales, are commonly attributed to edge energy effects. This report resolves an ambiguity in the definition and calculation of edge energies and presents an atomistic calculation of edge energies for free clusters. We also present a theory for size-dependent shapes of Pb nanoprecipitates in Al, introducing the concept of ''magic-shapes'' defined as precipitate shapes having near zero elastic strains when inserted into similarly shaped voids in the Al matrix. An algorithm for constructing a complete set of magic-shapes is presented. The experimental observations are explained by elastic strain energies and interfacial energies; edge energies play a negligible role. We replicate the experimental observations by selecting precipitates having magic-shapes and interfacial energies less than a cutoff value.

  4. Overview of Curved Cutting Edge Mills

    Directory of Open Access Journals (Sweden)

    M. S. Potapova

    2014-01-01

    Full Text Available Now that there is a need to increase a processing capacity, curved cutting edge mills find ever-growing use. Also known as “rough end”, “full-side”, and “heavy-duty” mills, they provide the increased depth and width values of milling owing to the width-sized chip separation. The analysis of produced mills allowed us both to reveal their basic design components (type of a shaft or basic opening, diameter and length of the cutting part, mill length, quantity of teeth, a tilt angle of a screw flute and to make their classification. The paper presents a classification of the profile types of cutting edges, which can be divided by form (flat, round, size (small, large, super-large, and symmetry (symmetrical and asymmetrical. The profile of the cutting edge is characterized by the following parameters: profile height, pitch of crests spherical radius of crest.A review of the curved cutting edge profile types allows us to build the geometrical constructions to define a form and the sizes of the chip load made by the cutting edge from a billet. It is shown that parameters of the cutting edge profile influence the form and the sizes (thickness and width of the chip load.The chip load thickness provided by the curved cutting edge mills exceeds that of observed when using the “smooth” cutting edge mills. A thickening degree of the chip load is changed with changing form and sizes of the cutting edge mill profile. Larger thickening is observed if the chip load is limited from below and from above by the marks of a single tooth (the first or second etc., and a length of the other teeth marks is minimum. The most achievable chip load thickness is equal to feed per revolution.Studying the references allowed us to formulate some rules to choose a cutting edge profile depending on a type of the processed material and a desirable roughness of the processed surface. It is important to note the following.When choosing a profile of the cutting edge

  5. Depth from Edge and Intensity Based Stereo.

    Science.gov (United States)

    1982-09-01

    something similar for a machine (be the similarity in mechanism or effect). ,1 1.1 The Stereopsi. Process in Man .4 In the course of primate ...Dorr ain • restrictions An understanding of its domain of intended use and an analysis of its performance capabilities will give us insight into a stereo...providing for the interpretation of cei: ain edges as being spurious or obscured, is both unrealistic and unacceptable - there will always be edges which

  6. Edge subdivision and edge multisubdivision versus some domination related parameters in generalized corona graphs

    Directory of Open Access Journals (Sweden)

    Magda Dettlaff

    2016-01-01

    Full Text Available Given a graph \\(G=(V,E\\, the subdivision of an edge \\(e=uv\\in E(G\\ means the substitution of the edge \\(e\\ by a vertex \\(x\\ and the new edges \\(ux\\ and \\(xv\\. The domination subdivision number of a graph \\(G\\ is the minimum number of edges of \\(G\\ which must be subdivided (where each edge can be subdivided at most once in order to increase the domination number. Also, the domination multisubdivision number of \\(G\\ is the minimum number of subdivisions which must be done in one edge such that the domination number increases. Moreover, the concepts of paired domination and independent domination subdivision (respectively multisubdivision numbers are defined similarly. In this paper we study the domination, paired domination and independent domination (subdivision and multisubdivision numbers of the generalized corona graphs.

  7. Frontal destabilization of Stonebreen, Edgeøya, Svalbard

    Directory of Open Access Journals (Sweden)

    T. Strozzi

    2017-02-01

    and synthetic aperture radar (SAR satellite data, a number of zones of velocity increases have been observed at formerly slow-flowing calving fronts on Svalbard. Here we present the dynamic evolution of the southern lobe of Stonebreen on Edgeøya. We observe a slowly steady retreat of the glacier front from 1971 until 2011, followed by a strong increase in ice surface velocity along with a decrease of volume and frontal extension since 2012. The considerable losses in ice thickness could have made the tide-water calving glacier, which is grounded below sea level some 6 km inland from the 2014 front, more sensitive to surface meltwater reaching its bed and/or warm ocean water increasing frontal ablation with subsequent strong multi-annual ice-flow acceleration.

  8. Losing your edge: climate change and the conservation value of range-edge populations.

    Science.gov (United States)

    Rehm, Evan M; Olivas, Paulo; Stroud, James; Feeley, Kenneth J

    2015-10-01

    Populations occurring at species' range edges can be locally adapted to unique environmental conditions. From a species' perspective, range-edge environments generally have higher severity and frequency of extreme climatic events relative to the range core. Under future climates, extreme climatic events are predicted to become increasingly important in defining species' distributions. Therefore, range-edge genotypes that are better adapted to extreme climates relative to core populations may be essential to species' persistence during periods of rapid climate change. We use relatively simple conceptual models to highlight the importance of locally adapted range-edge populations (leading and trailing edges) for determining the ability of species to persist under future climates. Using trees as an example, we show how locally adapted populations at species' range edges may expand under future climate change and become more common relative to range-core populations. We also highlight how large-scale habitat destruction occurring in some geographic areas where many species range edge converge, such as biome boundaries and ecotones (e.g., the arc of deforestation along the rainforest-cerrado ecotone in the southern Amazonia), can have major implications for global biodiversity. As climate changes, range-edge populations will play key roles in helping species to maintain or expand their geographic distributions. The loss of these locally adapted range-edge populations through anthropogenic disturbance is therefore hypothesized to reduce the ability of species to persist in the face of rapid future climate change.

  9. Gyrofluid computation of magnetic perturbation effects on turbulence and edge localized bursts

    Science.gov (United States)

    Peer, J.; Kendl, A.; Ribeiro, T. T.; Scott, B. D.

    2017-08-01

    The effects of non-axisymmetric resonant magnetic perturbation fields (RMPs) on saturated drift-wave turbulence and on ballooning mode bursts in the edge pedestal of tokamak plasmas are investigated by numerical simulations with a nonlinear six-moment electromagnetic gyrofluid model including zonal profile evolution. The vacuum RMP fields are screened by plasma response currents, so that magnetic transport by perturbed parallel motion is not significantly changed. Radial transport of both particles and heat is dominated by turbulent convection even for large RMP amplitudes, where formation of quasi-stationary convective structures leads to edge profile degradation. Modelling of ideal ballooning mode unstable edge profiles for single bursts including RMP fields causes resonant mode locking and destabilization.

  10. Study of loop-loop and loop-edge dislocation interactions in bcc iron

    DEFF Research Database (Denmark)

    Osetsky, Y.N.; Bacon, D.J.; Gao, F.

    2000-01-01

    that the evolution of heterogeneities such as dislocation decoration and rafts has serious impacts on the mechanical properties on neutron-irradiated metals. In the present work, atomic-scale computer modelling (ASCM) has been applied to study the mechanisms for the formation of such microstructure in bcc iron....... It is shown that glissile clusters with parallel Burgers vectors interact strongly and can form extended immobile complexes, i.e., rafts. Similar attractive interaction exists between dislocation loops and an edge dislocation. These two mechanisms may be responsible for the formation of extended complexes...... of dislocation loops below the extra half-plane of edge dislocations. The interaction energies between loops and between an edge dislocation and loops has been calculated as a function of distance using ASCM and the results for long-range interactions are in good agreement with the results of isotropic...

  11. Chiral random matrix model at finite chemical potential: Characteristic determinant and edge universality

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yizhuang, E-mail: yizhuang.liu@stonybrook.edu [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States); Nowak, Maciej A., E-mail: maciej.a.nowak@uj.edu.pl [M. Smoluchowski Institute of Physics and Mark Kac Complex Systems Research Center, Jagiellonian University, PL-30348 Krakow (Poland); Zahed, Ismail, E-mail: ismail.zahed@stonybrook.edu [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

    2016-08-15

    We derive an exact formula for the stochastic evolution of the characteristic determinant of a class of deformed Wishart matrices following from a chiral random matrix model of QCD at finite chemical potential. In the WKB approximation, the characteristic determinant describes a sharp droplet of eigenvalues that deforms and expands at large stochastic times. Beyond the WKB limit, the edges of the droplet are fuzzy and described by universal edge functions. At the chiral point, the characteristic determinant in the microscopic limit is universal. Remarkably, the physical chiral condensate at finite chemical potential may be extracted from current and quenched lattice Dirac spectra using the universal edge scaling laws, without having to solve the QCD sign problem.

  12. Teaching Evolution

    Science.gov (United States)

    Bryner, Jeanna

    2005-01-01

    Eighty years after the famous 1925 Scopes "monkey trial," which tested a teacher's right to discuss the theory of evolution in the classroom, evolution--and its most recent counterview, called "intelligent design"--are in the headlines again, and just about everyone seems to have an opinion. This past July, President Bush weighed in, telling…

  13. Acyclicity in edge-colored graphs

    DEFF Research Database (Denmark)

    Gutin, Gregory; Jones, Mark; Sheng, Bin

    2017-01-01

    A walk W in edge-colored graphs is called properly colored (PC) if every pair of consecutive edges in W is of different color. We introduce and study five types of PC acyclicity in edge-colored graphs such that graphs of PC acyclicity of type i is a proper superset of graphs of acyclicity of type i......+1, i=1,2,3,4. The first three types are equivalent to the absence of PC cycles, PC closed trails, and PC closed walks, respectively. While graphs of types 1, 2 and 3 can be recognized in polynomial time, the problem of recognizing graphs of type 4 is, somewhat surprisingly, NP-hard even for 2-edge-colored...... graphs (i.e., when only two colors are used). The same problem with respect to type 5 is polynomial-time solvable for all edge-colored graphs. Using the five types, we investigate the border between intractability and tractability for the problems of finding the maximum number of internally vertex...

  14. Trailing edge modifications for flatback airfoils.

    Energy Technology Data Exchange (ETDEWEB)

    Kahn, Daniel L. (University of California, Davis, CA); van Dam, C.P. (University of California, Davis, CA); Berg, Dale E.

    2008-03-01

    The adoption of blunt trailing edge airfoils (also called flatback airfoils) for the inboard region of large wind turbine blades has been proposed. Blunt trailing edge airfoils would not only provide a number of structural benefits, such as increased structural volume and ease of fabrication and handling, but they have also been found to improve the lift characteristics of thick airfoils. Therefore, the incorporation of blunt trailing edge airfoils would allow blade designers to more freely address the structural demands without having to sacrifice aerodynamic performance. These airfoils do have the disadvantage of generating high levels of drag as a result of the low-pressure steady or periodic flow in the near-wake of the blunt trailing edge. Although for rotors, the drag penalty appears secondary to the lift enhancement produced by the blunt trailing edge, high drag levels are of concern in terms of the negative effect on the torque and power generated by the rotor. Hence, devices are sought that mitigate the drag of these airfoils. This report summarizes the literature on bluff body vortex shedding and bluff body drag reduction devices and proposes four devices for further study in the wind tunnel.

  15. Should We Analyze for Trace Metal Contamination at the Edge, Bevel, and Edge Exclusion of Wafers?

    Science.gov (United States)

    Beebe, Meredith; Sparks, Chris; Carpio, Ron

    2003-09-01

    The edge, bevel, and edge exclusion area of a wafer has historically been difficult to monitor for trace metals. Standard trace metal surface techniques such as total reflection x-ray fluorescence spectroscopy, time-of-flight secondary ion mass spectrometry, and vapor phase decomposition inductively coupled plasma are currently not capable or have difficulty measuring metals to the edge and bevel of the wafer. With shared metrology toolsets and new materials being introduced into semiconductor fabs, it is important to measure possible contamination in these areas of the wafer. Tools that have edge grip pins or centering and aligning pins, also are at risk to contaminate wafers at the edge and bevel. A technique had been developed known as the beveled edge analysis tool that chemically extracts contamination from the edge, bevel and edge exclusion of a wafer that is then quantified by inductively coupled plasma mass spectrometry. In this study we will show correlation of this technique to standard trace element analysis methods. We will also present data from characterizing processes and fab tools that will benefit from this measurement.

  16. Study of airfoil trailing edge bluntness noise

    DEFF Research Database (Denmark)

    Zhu, Wei Jun; Shen, Wen Zhong; Sørensen, Jens Nørkær

    2010-01-01

    This paper deals with airfoil trailing edge noise with special focus on airfoils with blunt trailing edges. Two methods are employed to calculate airfoil noise: The flow/acoustic splitting method and the semi-empirical method. The flow/acoustic splitting method is derived from compressible Navier......-Stokes equations. It provides us possibilities to study details about noise generation mechanism. The formulation of the semi-empirical model is based on acoustic analogy and then curve-fitted with experimental data. Due to its high efficiency, such empirical relation is used for purpose of low noise airfoil...... design or optimization. Calculations from both methods are compared with exist experiments. The airfoil blunt noise is found as a function of trailing edge bluntness, Reynolds number, angle of attack, etc....

  17. Edge-Matching Problems with Rotations

    DEFF Research Database (Denmark)

    Ebbesen, Martin; Fischer, Paul; Witt, Carsten

    2011-01-01

    Edge-matching problems, also called puzzles, are abstractions of placement problems with neighborhood conditions. Pieces with colored edges have to be placed on a board such that adjacent edges have the same color. The problem has gained interest recently with the (now terminated) Eternity II...... puzzle, and new complexity results. In this paper we consider a number of settings which differ in size of the puzzles and the manipulations allowed on the pieces. We investigate the effect of allowing rotations of the pieces on the complexity of the problem, an aspect that is only marginally treated so...... far. We show that some problems have polynomial time algorithms while others are NP-complete. Especially we show that allowing rotations in one-row puzzles makes the problem NP-hard. We moreover show that many commonly considered puzzles can be emulated by simple puzzles with quadratic pieces, so...

  18. Flow distortion at a dense forest edge

    DEFF Research Database (Denmark)

    Dellwik, Ebba; Bingöl, Ferhat; Mann, Jakob

    2014-01-01

    The flow near tall forest edges is complex, yet poorly described. A field experiment using two meteorological masts equipped with sonic anemometers and a horizontally staring lidar was performed upwind and downwind of the interface between an open flat farmland and a tall (hc = 24 m) beech forest...... qualitatively be explained with the concept of eddy‐blocking by the canopy top, which could also explain the observed increase in lateral variance and the decrease in the vertical variance. Despite the short distance to the edge of approximately 1.5hc, the beginning of a new internal boundary layer was visible...... at 1.04hc as a decrease in the vertical momentum flux. At this level, as well as within the forest, the results depended on the wind speed. The presented findings enhance the understanding of the forest edge flow and are useful for model verification and development....

  19. Topological edge modes in multilayer graphene systems.

    Science.gov (United States)

    Ge, Lixin; Wang, Li; Xiao, Meng; Wen, Weijia; Chan, C T; Han, Dezhuan

    2015-08-24

    Plasmons can be supported on graphene sheets as the Dirac electrons oscillate collectively. A tight-binding model for graphene plasmons is a good description as the field confinement in the normal direction is strong. With this model, the topological properties of plasmonic bands in multilayer graphene systems are investigated. The Zak phases of periodic graphene sheet arrays are obtained for different configurations. Analogous to Su-Schrieffer-Heeger (SSH) model in electronic systems, topological edge plasmon modes emerge when two periodic graphene sheet arrays with different Zak phases are connected. Interestingly, the dispersion of these topological edge modes is the same as that in the monolayer graphene and is invariant as the geometric parameters of the structure such as the separation and period change. These plasmonic edge states in multilayer graphene systems can be further tuned by electrical gating or chemical doping.

  20. Leading-edge vortex lifts swifts.

    Science.gov (United States)

    Videler, J J; Stamhuis, E J; Povel, G D E

    2004-12-10

    The current understanding of how birds fly must be revised, because birds use their hand-wings in an unconventional way to generate lift and drag. Physical models of a common swift wing in gliding posture with a 60 degrees sweep of the sharp hand-wing leading edge were tested in a water tunnel. Interactions with the flow were measured quantitatively with digital particle image velocimetry at Reynolds numbers realistic for the gliding flight of a swift between 3750 and 37,500. The results show that gliding swifts can generate stable leading-edge vortices at small (5 degrees to 10 degrees) angles of attack. We suggest that the flow around the arm-wings of most birds can remain conventionally attached, whereas the swept-back hand-wings generate lift with leading-edge vortices.

  1. Long coherence times for edge spins

    Science.gov (United States)

    Kemp, Jack; Yao, Norman Y.; Laumann, Christopher R.; Fendley, Paul

    2017-06-01

    We show that in certain one-dimensional spin chains with open boundary conditions, the edge spins retain memory of their initial state for very long times, even at infinite temperature. The long coherence times do not require disorder, only an ordered phase. In the integrable Ising and XYZ chains, the presence of a strong zero mode means the coherence time is infinite. When Ising is perturbed by interactions breaking the integrability, the coherence time remains exponentially long in the perturbing couplings. We show that this is a consequence of an edge ‘almost’ strong zero mode that almost commutes with the Hamiltonian. We compute this operator explicitly, allowing us to estimate accurately the plateau value of edge spin autocorrelator.

  2. Floquet edge states in germanene nanoribbons

    KAUST Repository

    Tahir, M.

    2016-08-23

    We theoretically demonstrate versatile electronic properties of germanene monolayers under circularly, linearly, and elliptically polarized light. We show for the high frequency regime that the edge states can be controlled by tuning the amplitude of the light and by applying a static electric field. For circularly polarized light the band gap in one valley is reduced and in the other enhanced, enabling single valley edge states. For linearly polarized light spin-split states are found for both valleys, being connected by time reversal symmetry. The effects of elliptically polarized light are similar to those of circularly polarized light. The transport properties of zigzag nanoribbons in the presence of disorder confirm a nontrivial nature of the edge states under circularly and elliptically polarized light.

  3. Topological edge modes in multilayer graphene systems

    KAUST Repository

    Ge, Lixin

    2015-08-10

    Plasmons can be supported on graphene sheets as the Dirac electrons oscillate collectively. A tight-binding model for graphene plasmons is a good description as the field confinement in the normal direction is strong. With this model, the topological properties of plasmonic bands in multilayer graphene systems are investigated. The Zak phases of periodic graphene sheet arrays are obtained for different configurations. Analogous to Su-Schrieffer-Heeger (SSH) model in electronic systems, topological edge plasmon modes emerge when two periodic graphene sheet arrays with different Zak phases are connected. Interestingly, the dispersion of these topological edge modes is the same as that in the monolayer graphene and is invariant as the geometric parameters of the structure such as the separation and period change. These plasmonic edge states in multilayer graphene systems can be further tuned by electrical gating or chemical doping. © 2015 Optical Society of America.

  4. Edge modulation of electronics and transport properties of cliff-edge phosphorene nanoribbons

    Science.gov (United States)

    Guo, Caixia; Wang, Tianxing; Xia, Congxin; Liu, Yufang

    2017-12-01

    Based on the first-principles calculations, we study the electronic structures and transport properties of cliff-like edge phosphorene nanoribbons (CPNRs), considering different types of edge passivation. The band structures of bare CPNRs possess the metallic features; while hydrogen (H), fluorine (F), chlorine (Cl) and oxygen (O) atoms-passivated CPNRs are semiconductor materials, and the band gap values monotonically decrease when the ribbon width increases. Moreover, the H and F-passivated CPNRs exhibit the direct band gap characteristics, while the Cl and O-passivated cases show the features of indirect band gap. In addition, the edge passivated CPNRs are more energetically stable than bare edge case. Meanwhile, our results also show that the transport properties of the CPNRs can be obviously influenced by the different edge passivation.

  5. Edge detection in landing budgerigars (Melopsittacus undulatus.

    Directory of Open Access Journals (Sweden)

    Partha Bhagavatula

    Full Text Available BACKGROUND: While considerable scientific effort has been devoted to studying how birds navigate over long distances, relatively little is known about how targets are detected, obstacles are avoided and smooth landings are orchestrated. Here we examine how visual features in the environment, such as contrasting edges, determine where a bird will land. METHODOLOGY/PRINCIPAL FINDINGS: Landing in budgerigars (Melopsittacus undulatus was investigated by training them to fly from a perch to a feeder, and video-filming their landings. The feeder was placed on a grey disc that produced a contrasting edge against a uniformly blue background. We found that the birds tended to land primarily at the edge of the disc and walk to the feeder, even though the feeder was in the middle of the disc. This suggests that the birds were using the visual contrast at the boundary of the disc to target their landings. When the grey level of the disc was varied systematically, whilst keeping the blue background constant, there was one intermediate grey level at which the budgerigar's preference for the disc boundary disappeared. The budgerigars then landed randomly all over the test surface. Even though this disc is (for humans clearly distinguishable from the blue background, it offers very little contrast against the background, in the red and green regions of the spectrum. CONCLUSIONS: We conclude that budgerigars use visual edges to target and guide landings. Calculations of photoreceptor excitation reveal that edge detection in landing budgerigars is performed by a color-blind luminance channel that sums the signals from the red and green photoreceptors, or, alternatively, receives input from the red double-cones. This finding has close parallels to vision in honeybees and primates, where edge detection and motion perception are also largely color-blind.

  6. Physics-based edge evaluation for improved color constancy

    NARCIS (Netherlands)

    Gijsenij, A.; Gevers, T.; van de Weijer, J.

    2009-01-01

    Edge-based color constancy makes use of image derivatives to estimate the illuminant. However, different edge types exist in real-world images such as shadow, geometry, material and highlight edges. These different edge types may have a distinctive influence on the performance of the illuminant

  7. 16 CFR 1211.12 - Requirements for edge sensors.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Requirements for edge sensors. 1211.12... Requirements for edge sensors. (a) Normal operation test. (1) When installed on a representative door edge, an edge sensor shall actuate upon the application of a 15 pounds (66.7 N) or less force in the direction...

  8. Multi-scale Regions from Edge Fragments

    DEFF Research Database (Denmark)

    Kazmi, Wajahat; Andersen, Hans Jørgen

    2014-01-01

    In this article we introduce a novel method for detecting multi-scale salient regions around edges using a graph based image compression algorithm. Images are recursively decomposed into triangles arranged into a binary tree using linear interpolation. The entropy of any local region of the image...... to estimate regions. Salient regions are thus formed as stable regions around edges. Tree hierarchy is then used to generate multi-scale regions. We evaluate our detector by performing image retrieval tests on our building database which shows that combined with Spin Images (Lazebnik et al., 2003...

  9. Flow rates for sharp-edged orifices

    Science.gov (United States)

    Groesbeck, W. A.; Manning, F. L.

    1975-01-01

    Two charts are proposed for calculating the flow coefficient and the area correction factor used in the equation for the flow rate through a sharp-edged orifice. The proposed charts account for variations in the discharge coefficient of sharp-edged orifices and can be used with any pressure ratio for both subcritical and supercritical flow conditions. They can also be used for any gas by using the appropriate gas constant and ratio of specific heats. The application of the charts is illustrated by examples.

  10. Plasma edge modelling with ICRF coupling

    Directory of Open Access Journals (Sweden)

    Zhang Wei

    2017-01-01

    Full Text Available The physics of Radio-Frequency (RF wave heating in the Ion Cyclotron Range of Frequencies (ICRF in the core plasmas of fusion devices are relatively well understood while those in the Scrape-Off Layer (SOL remain still unresolved. This paper is dedicated to study the ICRF interactions with the plasma edge, mainly from the theoretical and numerical point of view, in particular with the 3D edge plasma fluid and neutral transport code EMC3-EIRENE and various wave codes. Here emphasis is given to the improvement of ICRF coupling with local gas puffing and to the ICRF induced density convection in the SOL.

  11. Plasma edge modelling with ICRF coupling

    Science.gov (United States)

    Zhang, Wei; Coster, David; Feng, Yuhe; Lunt, Tilmann; Aguiam, Diogo; Bilato, Roberto; Bobkov, Volodymyr; Jacquot, Jonathan; Jacquet, Philippe; Lerche, Ernesto; Noterdaeme, Jean-Marie; Tierens, Wouter

    2017-10-01

    The physics of Radio-Frequency (RF) wave heating in the Ion Cyclotron Range of Frequencies (ICRF) in the core plasmas of fusion devices are relatively well understood while those in the Scrape-Off Layer (SOL) remain still unresolved. This paper is dedicated to study the ICRF interactions with the plasma edge, mainly from the theoretical and numerical point of view, in particular with the 3D edge plasma fluid and neutral transport code EMC3-EIRENE and various wave codes. Here emphasis is given to the improvement of ICRF coupling with local gas puffing and to the ICRF induced density convection in the SOL.

  12. AliEn - EDG Interoperability in ALICE

    OpenAIRE

    Bagnasco, S.; Barbera, R.; Buncic, P; Carminati, F; Cerello, P.; Saiz, P.

    2003-01-01

    AliEn (ALICE Environment) is a GRID-like system for large scale job submission and distributed data management developed and used in the context of ALICE, the CERN LHC heavy-ion experiment. With the aim of exploiting upcoming Grid resources to run AliEn-managed jobs and store the produced data, the problem of AliEn-EDG interoperability was addressed and an in-terface was designed. One or more EDG (European Data Grid) User Interface machines run the AliEn software suite (Cluster Monitor, Stora...

  13. Trinity Evolution.

    Science.gov (United States)

    Rush, Shannon M

    2010-06-01

    Trinity Evolution Cryopreserved Cell Viable Bone Matrix is a minimally manipulated, human cellular, and tissue-based allograft containing adult mesenchymal stem cells, osteoprogenitor cells, and a demineralized cortical component. The cancellous bone used to produce Trinity Evolution is derived from freshly recovered donor tissue by Food and Drug Administration-registered facilities and processed under aseptic conditions. Preclinical in vivo and in vitro testing as well as strict donor screening has demonstrated the safety of Trinity Evolution as well as its osteoinductive and osteogenic potential contained within a natural osteoconductive matrix.

  14. Stellar evolution

    CERN Document Server

    Meadows, A J

    2013-01-01

    Stellar Evolution, Second Edition covers the significant advances in the understanding of birth, life, and death of stars.This book is divided into nine chapters and begins with a description of the characteristics of stars according to their brightness, distance, size, mass, age, and chemical composition. The next chapters deal with the families, structure, and birth of stars. These topics are followed by discussions of the chemical composition and the evolution of main-sequence stars. A chapter focuses on the unique features of the sun as a star, including its evolution, magnetic fields, act

  15. High electrochemical selectivity of edge versus terrace sites in two-dimensional layered MoS2 materials.

    Science.gov (United States)

    Wang, Haotian; Zhang, Qianfan; Yao, Hongbin; Liang, Zheng; Lee, Hyun-Wook; Hsu, Po-Chun; Zheng, Guangyuan; Cui, Yi

    2014-12-10

    Exploring the chemical reactivity of different atomic sites on crystal surface and controlling their exposures are important for catalysis and renewable energy storage. Here, we use two-dimensional layered molybdenum disulfide (MoS2) to demonstrate the electrochemical selectivity of edge versus terrace sites for Li-S batteries and hydrogen evolution reaction (HER). Lithium sulfide (Li2S) nanoparticles decorates along the edges of the MoS2 nanosheet versus terrace, confirming the strong binding energies between Li2S and the edge sites and guiding the improved electrode design for Li-S batteries. We also provided clear comparison of HER activity between edge and terrace sites of MoS2 beyond the previous theoretical prediction and experimental proof.

  16. Schumpeter's Evolution

    DEFF Research Database (Denmark)

    Andersen, Esben Sloth

    This draft of a book on Schumpeter is distributed for commenting. It is a stylised intellectual biography that focus on the emergence and extension of the Schumpeterian vision and analysis of economic and social evolution. The draft provides novel interpretations of Schumpeter's six major books. He...... originally developed his evolutionary research programme in Wesen from 1908 by studying the inherent limitations of Neoclassical Economics. He presented core results on economic evolution and sketched an extension evolutionary analysis to all social sciences in Entwicklung from 1912. He made a partial...... reworking of his basic theory of economic evolution in Development from 1934, and this reworking was continued in Cycles from 1939. Here Schumpeter also tried to handle the statistical and historical evidence on the waveform evolution of the capitalist economy. Capitalism from 1942 modified the model...

  17. Edge control in CNC polishing, paper 2: simulation and validation of tool influence functions on edges.

    Science.gov (United States)

    Li, Hongyu; Walker, David; Yu, Guoyu; Sayle, Andrew; Messelink, Wilhelmus; Evans, Rob; Beaucamp, Anthony

    2013-01-14

    Edge mis-figure is regarded as one of the most difficult technical issues for manufacturing the segments of extremely large telescopes, which can dominate key aspects of performance. A novel edge-control technique has been developed, based on 'Precessions' polishing technique and for which accurate and stable edge tool influence functions (TIFs) are crucial. In the first paper in this series [D. Walker Opt. Express 20, 19787-19798 (2012)], multiple parameters were experimentally optimized using an extended set of experiments. The first purpose of this new work is to 'short circuit' this procedure through modeling. This also gives the prospect of optimizing local (as distinct from global) polishing for edge mis-figure, now under separate development. This paper presents a model that can predict edge TIFs based on surface-speed profiles and pressure distributions over the polishing spot at the edge of the part, the latter calculated by finite element analysis and verified by direct force measurement. This paper also presents a hybrid-measurement method for edge TIFs to verify the simulation results. Experimental and simulation results show good agreement.

  18. Conical shell edge disturbance : An engineer's derivation

    NARCIS (Netherlands)

    Blaauwendraad, J.; Hoefakker, JH

    2016-01-01

    Because a rigorous bending theory for thin shells of revolution is complicated, attempts have been made for reliable approximations of the edge disturbance problem under axisymmetric loading. A well-known one was published by Geckeler [1, 2], who obtained his approximation by mathematical

  19. Fermi Bubble Edges: Spectrum and Diffusion Function

    Science.gov (United States)

    Keshet, Uri; Gurwich, Ilya

    2017-05-01

    Current measurements of the γ-ray Fermi bubbles (FB) are based on model-dependent tracers, carry substantial systematic uncertainties, and contain some discrepancies between each other. We show that gradient filters pick out the FB edges, which are found to smoothly connect to the bipolar X-ray structure emanating from the Galactic center, thus supporting the interpretation of the FBs as a Galactic-scale phenomenon. The sharp edges facilitate a direct, model-free measurement of the peripheral FB spectrum. The result is strikingly similar to the full FB-integrated spectrum, softened by a power law of index η ≃ (0.2-0.3). This is naturally explained, in both hadronic and leptonic models, if cosmic rays are injected at the edge, and diffuse away preferentially at higher energies E. The inferred, averaged diffusion function in the (more plausible) leptonic model, D{(E)≃ {10}29.5(E/10{GeV})}0.48+/- 0.02 {{cm}}2 {{{s}}}-1, is consistent with estimates for Kraichnan-like turbulence. Our results, in particular the minute spatial variations in η, indicate that the FB edge is a strong, Mach ≳5, forward shock.

  20. Performance of active edge pixel sensors

    CERN Document Server

    Bomben, Marco; Bagolini, Alvise; Boscardin, Maurizio; Bosisio, Luciano; Calderini, Giovanni; D'Eramo, Louis; Giacomini, Gabriele; Marchiori, Giovanni; Zorzi, Nicola; Rummler, Andre; Weingarten, Jens

    2017-01-01

    this paper the performance of these modules are reported. In particular the lateral extension of the detection volume, beyond the pixel region, is investigated and the results show high hit efficiency also at the detector edge, even in presence of guard rings.

  1. Edge Delamination of Monolayer Transition Metal Dichalcogenides.

    Science.gov (United States)

    Ly, Thuc Hue; Yun, Seok Joon; Thi, Quoc Huy; Zhao, Jiong

    2017-07-25

    Delamination of thin films from the supportive substrates is a critical issue within the thin film industry. The emergent two-dimensional, atomic layered materials, including transition metal dichalcogenides, are highly flexible; thus buckles and wrinkles can be easily generated and play vital roles in the corresponding physical properties. Here we introduce one kind of patterned buckling behavior caused by the delamination from a substrate initiated at the edges of the chemical vapor deposition synthesized monolayer transition metal dichalcogenides, led by thermal expansion mismatch. The atomic force microscopy and optical characterizations clearly showed the puckered structures associated with the strain, whereas the transmission electron microscopy revealed the special sawtooth-shaped edges, which break the geometrical symmetry for the buckling behavior of hexagonal samples. The condition of the edge delamination is in accordance with the fracture behavior of thin film interfaces. This edge delamination and buckling process is universal for most ultrathin two-dimensional materials, which requires more attention in various future applications.

  2. Fetch requirements near a forest edge

    NARCIS (Netherlands)

    Breugel, van P.B.; Klaassen, W.; Moors, E.J.

    1999-01-01

    Measurements on forest-atmosphere exchange should be executed some distance from the forest boundaries to be representative for this forest. In this study the minimum fetch at measuring height is estimated by analysing measurements just above a mixed forest stand near the edge. The objective was to

  3. Edge maps: Representing flow with bounded error

    KAUST Repository

    Bhatia, Harsh

    2011-03-01

    Robust analysis of vector fields has been established as an important tool for deriving insights from the complex systems these fields model. Many analysis techniques rely on computing streamlines, a task often hampered by numerical instabilities. Approaches that ignore the resulting errors can lead to inconsistencies that may produce unreliable visualizations and ultimately prevent in-depth analysis. We propose a new representation for vector fields on surfaces that replaces numerical integration through triangles with linear maps defined on its boundary. This representation, called edge maps, is equivalent to computing all possible streamlines at a user defined error threshold. In spite of this error, all the streamlines computed using edge maps will be pairwise disjoint. Furthermore, our representation stores the error explicitly, and thus can be used to produce more informative visualizations. Given a piecewise-linear interpolated vector field, a recent result [15] shows that there are only 23 possible map classes for a triangle, permitting a concise description of flow behaviors. This work describes the details of computing edge maps, provides techniques to quantify and refine edge map error, and gives qualitative and visual comparisons to more traditional techniques. © 2011 IEEE.

  4. Reading Edge. What Works Clearinghouse Intervention Report

    Science.gov (United States)

    What Works Clearinghouse, 2012

    2012-01-01

    "Reading Edge" is a middle school literacy program that emphasizes cooperative learning, goal setting, feedback, classroom management techniques, and the use of metacognitive strategy, whereby students assess their own skills and learn to apply new ones. The program is a component of the "Success for All"[superscript 2]…

  5. Plasma oscillations of edge Dirac fermions

    Science.gov (United States)

    Volkov, V. A.; Zagorodnev, I. V.

    2013-06-01

    The dispersion law of one-dimensional plasmons in a quasi-one-dimensional system of massless Dirac fermions has been calculated. Two model two-dimensional systems where bands of edge states filled with such Dirac fermions appear at the edge have been considered. Edge states in the first system, topological insulator, are due to topological reasons. Edge states in the second system, system of massive Dirac fermions, have Tamm origin. It has been shown that the dispersion laws of plasmons in both systems in the long-wavelength limit differ only in the definition of the parameters (velocity and localization depth of Dirac fermions). The frequency of plasmons is formally quantum (ω ∝ ħ -1/2) and, in the case of the Coulomb interaction between electrons, depends slightly on the Fermi level E F. The dependence on E F is stronger in the case of short-range interaction. The quantum features of oscillations of massless one-dimensional Dirac fermions are removed by introducing the mass of Dirac fermions at the Fermi level and their density. Correspondence to the dispersion law of classical one-dimensional plasma oscillations in a narrow stripe of "Schrödinger" electrons has been revealed.

  6. Superconducting Metallic Glass Transition-Edge-Sensors

    Science.gov (United States)

    Hays, Charles C. (Inventor)

    2013-01-01

    A superconducting metallic glass transition-edge sensor (MGTES) and a method for fabricating the MGTES are provided. A single-layer superconducting amorphous metal alloy is deposited on a substrate. The single-layer superconducting amorphous metal alloy is an absorber for the MGTES and is electrically connected to a circuit configured for readout and biasing to sense electromagnetic radiation.

  7. MODIFIED EDGE FED SIERPINSKI CARPET MINIATURIZED ...

    African Journals Online (AJOL)

    This paper presented a modified edge fed Sierpinski carpet microstrip patch antenna for antenna miniaturization. The proposed design was etched as Sierpinski carpet to lower the antenna resonant frequency, which is used to reduce the conventional patch antenna size. After the Sierpinski carpet second iteration, the ...

  8. On A Graph Formalism for Ordered Edges

    NARCIS (Netherlands)

    de Mol, M.J.; Rensink, Arend; Küster, J.; Tuosto, E.

    2010-01-01

    Though graphs are flexible enough to model any kind of data structure in principle, for some structures this results in a rather large overhead. This is for instance true for lists, i.e., edges that are meant to point to an ordered collection of nodes. Such structures are frequently encountered, for

  9. Leading-Edge Vortex lifts swifts

    NARCIS (Netherlands)

    Videler, JJ; Stamhuis, EJ; Povel, GDE

    2004-01-01

    The current understanding of how birds fly must be revised, because birds use their hand-wings in an unconventional way to generate lift and drag. Physical models of a common swift wing in gliding posture with a 60degrees sweep of the sharp hand-wing leading edge were tested in a water tunnel.

  10. Acoustic streaming of a sharp edge.

    Science.gov (United States)

    Ovchinnikov, Mikhail; Zhou, Jianbo; Yalamanchili, Satish

    2014-07-01

    Anomalous acoustic streaming is observed emanating from sharp edges of solid bodies that are vibrating in fluids. The streaming velocities can be orders of magnitude higher than expected from the Rayleigh streaming at similar amplitudes of vibration. Acoustic velocity of fluid relative to a solid body diverges at a sharp edge, giving rise to a localized time-independent body force acting on the fluid. This force results in a formation of a localized jet. Two-dimensional numerical simulations are performed to predict acoustic streaming for low amplitude vibration using two methods: (1) Steady-state solution utilizing perturbation theory and (2) direct transient solution of the Navier-Stokes equations. Both analyses agree with each other and correctly predict the streaming of a sharp-edged vibrating blade measured experimentally. The origin of the streaming can be attributed to the centrifugal force of the acoustic fluid flow around a sharp edge. The dependence of this acoustic streaming on frequency and velocity is examined using dimensional analysis. The dependence law is devised and confirmed by numerical simulations.

  11. On dust in tokamak edge plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Krasheninnikov, S.I. [Jacobs School of Engineering, Department of Mechanical and Aerospace Engineering, University of California at San Diego, Engineering Building II, room 474, 9500 Gilman Drive, La Jolla, CA 92093-0411 (United States)]. E-mail: skrash@mae.ucsd.edu; Soboleva, T.K. [UNAM, Mexico, DF (Mexico); Kurchatov Institute, Moscow (Russian Federation); Tomita, Y. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Smirnov, R.D. [Graduate University for Advanced Studies, Toki, Gifu 509-5292 (Japan); Janev, R.K. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan)

    2005-03-01

    We study the dust particle dynamics in tokamak edge plasmas, with special emphasis on dust particle transport in the sheath and plasma recycling regions. The characteristics of this transport have been examined for both smooth and corrugated wall surfaces. The implications of dust particle transport in the divertor region on the core plasma contamination with impurities have also been examined.

  12. Shaping the edges using flowdrill technology

    Directory of Open Access Journals (Sweden)

    W. Matysiak

    2015-01-01

    Full Text Available In this paper, was presented the results of experimental studies of the edgetrimming process obtained using technology Flowdrill, shows distributions of thickness and height of recurving edging and its microhardness made of aluminum, mild steel and stainless steel.

  13. Evaluation of alternative snow plow cutting edges.

    Science.gov (United States)

    2009-05-01

    With approximately 450 snow plow trucks, the Maine Department of Transportation (MaineDOT) uses in : excess of 10,000 linear feet of plow cutting edges each winter season. Using the 2008-2009 cost per linear : foot of $48.32, the Departments total co...

  14. Biomechanical study on the edge shapes for penetrating keratoplasty.

    Science.gov (United States)

    Lee, Heow Pueh; Zhuang, Han

    2012-01-01

    A parametric study to investigate the compressive and the shear stress distributions for various edge shapes created during penetrating keratoplasty (PK) using femtosecond laser is reported. The finite element analysis has been implemented using ABAQUS to study the cornea with various edge shapes, namely the standard edge shape, the zigzag edge shape, the top hat edge shape and the mushroom edge shape for PK. The ratio of maximum compressive stress to maximum shear stress is used as the main factor to assess the relative merits of wound healing rate for different edge shapes. For the typical values of tissue mechanical properties, the zigzag edge shape has the highest ratio of maximum compressive stress to maximum shear stress (11.1 in the xy-direction and 3.7 in the yz-direction), followed by the mushroom edge shape (7.7 in the xy-direction and 3.2 in the yz-direction). The ratios for the top hat and the standard edge shapes are even lower in both directions. A sensitivity analysis of the model has been done to demonstrate that the zigzag edge shape always results in the highest ratios of stresses regardless of the difference in the tissue mechanical properties. The zigzag edge shape also gives the lowest dioptric power D = 45.4. The present results imply that the zigzag edge shape provides the best wound healing rate and optical outcome among the four edge shapes models for PK.

  15. Defects' geometric feature recognition based on infrared image edge detection

    Science.gov (United States)

    Junyan, Liu; Qingju, Tang; Yang, Wang; Yumei, Lu; Zhiping, Zhang

    2014-11-01

    Edge detection is an important technology in image segmentation, feature extraction and other digital image processing areas. Boundary contains a wealth of information in the image, so to extract defects' edges in infrared images effectively enables the identification of defects' geometric features. This paper analyzed the detection effect of classic edge detection operators, and proposed fuzzy C-means (FCM) clustering-Canny operator algorithm to achieve defects' edges in the infrared images. Results show that the proposed algorithm has better effect than the classic edge detection operators, which can identify the defects' geometric feature much more completely and clearly. The defects' diameters have been calculated based on the image edge detection results.

  16. Edge-detect interpolation for direct digital periapical images

    Energy Technology Data Exchange (ETDEWEB)

    Song, Nam Kyu; Koh, Kwang Joon [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Chonbuk National University, Chonju (Korea, Republic of)

    1998-02-15

    The purpose of this study was to aid in the use of the digital images by edge-detect interpolation for direct digital periapical images using edge-deted interpolation. This study was performed by image processing of 20 digital periapical images; pixel replication, linear non-interpolation, linear interpolation, and edge-sensitive interpolation. The obtained results were as follows: 1. Pixel replication showed blocking artifact and serious image distortion. 2. Linear interpolation showed smoothing effect on the edge. 3. Edge-sensitive interpolation overcame the smoothing effect on the edge and showed better image.

  17. Independent component analysis of edge information for face recognition

    CERN Document Server

    Karande, Kailash Jagannath

    2013-01-01

    The book presents research work on face recognition using edge information as features for face recognition with ICA algorithms. The independent components are extracted from edge information. These independent components are used with classifiers to match the facial images for recognition purpose. In their study, authors have explored Canny and LOG edge detectors as standard edge detection methods. Oriented Laplacian of Gaussian (OLOG) method is explored to extract the edge information with different orientations of Laplacian pyramid. Multiscale wavelet model for edge detection is also propos

  18. CO2 fluxes near a forest edge

    DEFF Research Database (Denmark)

    Sogachev, Andrey; Leclerc, Monique Y.; Zhang, Gensheng

    2008-01-01

    In contrast with recent advances on the dynamics of the flow at a forest edge, few studies have considered its role on scalar transport and, in particular, on CO2 transfer. The present study addresses the influence of the abrupt roughness change on forest atmosphere CO2 exchange and contrasts...... the concentration and flux fields against those of a uniform forested surface. We use an atmospheric boundary layer two-equation closure model that accounts for the flow dynamics and vertical divergence of CO2 sources/sinks within a plant canopy. This paper characterizes the spatial variation of CO2 fluxes...... as a function of both sources/sinks distribution and the vertical structure of the canopy. Results suggest that the ground source plays a major role in the formation of wave-like vertical CO2 flux behavior downwind of a forest edge, despite the fact that the contribution of foliage sources/sinks changes...

  19. Edges of Saturn's rings are fractal.

    Science.gov (United States)

    Li, Jun; Ostoja-Starzewski, Martin

    2015-01-01

    The images recently sent by the Cassini spacecraft mission (on the NASA website http://saturn.jpl.nasa.gov/photos/halloffame/) show the complex and beautiful rings of Saturn. Over the past few decades, various conjectures were advanced that Saturn's rings are Cantor-like sets, although no convincing fractal analysis of actual images has ever appeared. Here we focus on four images sent by the Cassini spacecraft mission (slide #42 "Mapping Clumps in Saturn's Rings", slide #54 "Scattered Sunshine", slide #66 taken two weeks before the planet's Augus't 200'9 equinox, and slide #68 showing edge waves raised by Daphnis on the Keeler Gap) and one image from the Voyager 2' mission in 1981. Using three box-counting methods, we determine the fractal dimension of edges of rings seen here to be consistently about 1.63 ~ 1.78. This clarifies in what sense Saturn's rings are fractal.

  20. Scattering of waves by axisymmetrical edge

    Science.gov (United States)

    Kaloshin, V. A.; Popov, A. P.

    1985-01-01

    A method of physical theory of diffraction (PTD) in an axisymmetric problem is used to obtain the first two terms of the uniform asymptotics of the radiation pattern of an edge wave with respect to inverse semiinteger powers of the wavenumber expressed through a two-term uniform asymptotics of the corresponding two-dimensional problem. As examples, calculations are made of: (1) the uniform asymptotics of the correction refining the Kirchhoff approximation for the radiation pattern of an axisymmetric reflector antenna; and (2) the asymptotics of the radiation pattern of symmetric modes from the open end of a circular flanged waveguide. An improvement of the PTD method is proposed for calculating the second term of the uniform asymptotics of an edge wave with respect to inverse powers of the wavenumber; the example of the diffraction of a toroidal wave by a bicone is considered.

  1. Quantum nature of edge magnetism in graphene.

    Science.gov (United States)

    Golor, Michael; Wessel, Stefan; Schmidt, Manuel J

    2014-01-31

    It is argued that the subtle crossover from decoherence-dominated classical magnetism to fluctuation-dominated quantum magnetism is experimentally accessible in graphene nanoribbons. We show that the width of a nanoribbon determines whether the edge magnetism is on the classical side, on the quantum side, or in between. In the classical regime, decoherence is dominant and leads to static spin polarizations at the ribbon edges, which are well described by mean-field theories. The quantum Zeno effect is identified as the basic mechanism which is responsible for the spin polarization and thereby enables the application of graphene in spintronics. On the quantum side, however, the spin polarization is destroyed by dynamical processes. The great tunability of graphene magnetism thus offers a viable route for the study of the quantum-classical crossover.

  2. A Review of Classic Edge Detectors

    Directory of Open Access Journals (Sweden)

    Haldo Spontón

    2015-06-01

    Full Text Available In this paper some of the classic alternatives for edge detection in digital images are studied. The main idea behind edge detection is to find where abrupt changes in the intensity of an image have occurred. The first family of algorithms reviewed in this work uses the first derivative to find the changes of intensity, such as Sobel, Prewitt and Roberts. In the second reviewed family it is used second derivative, for example in algorithms like Marr-Hildreth and Haralick. Results obtained from a qualitative point of view (perceptual and from a quantitative point of view (number of operations, execution time are compared, considering different ways to convolve an image with a kernel (step required in some of the algorithms.

  3. Edge-disjoint Hamiltonian cycles in hypertournaments

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2006-01-01

    We introduce a method for reducing k-tournament problems, for k >= 3, to ordinary tournaments, that is, 2-tournaments. It is applied to show that a k-tournament on n >= k + 1 + 24d vertices (when k >= 4) or on n >= 30d + 2 vertices (when k = 3) has d edge-disjoint Hamiltonian cycles if and only i......) 2005 Wiley Periodicals, Inc....

  4. Edge-on View of Saturn's Rings

    Science.gov (United States)

    1996-01-01

    TOP - This is a NASA Hubble Space Telescope snapshot of Saturn with its rings barely visible. Normally, astronomers see Saturn with its rings tilted. Earth was almost in the plane of Saturn's rings, thus the rings appear edge-on.In this view, Saturn's largest moon, Titan, is casting a shadow on Saturn. Titan's atmosphere is a dark brown haze. The other moons appear white because of their bright, icy surfaces. Four moons - from left to right, Mimas, Tethys, Janus, and Enceladus - are clustered around the edge of Saturn's rings on the right. Two other moons appear in front of the ring plane. Prometheus is on the right edge; Pandora, on the left. The rings also are casting a shadow on Saturn because the Sun was above the ring plane.BOTTOM - This photograph shows Saturn with its rings slightly tilted. The moon called Dione, on the lower right, is casting a long, thin shadow across the whole ring system due to the setting Sun on the ring plane. The moon on the upper left of Saturn is Tethys.Astronomers also are studying the unusual appearance of Saturn's rings. The bottom image displays a faint, narrow ring, the F-ring just outside the main ring, which normally is invisible from Earth. Close to the edge of Saturn's disk, the front section of rings seem brighter and more yellow than the back due to the additional lumination by yellowish Saturn.The color images were assembled from separate exposures taken August 6 (top) and November 17 (bottom), 1995 with the Wide Field Planetary Camera-2.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.This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

  5. Edge Effects in Finite Elongated Graphene Nanoribbons

    OpenAIRE

    Hod, Oded; Peralta, Juan E.; Scuseria, Gustavo E.

    2007-01-01

    We analyze the relevance of finite-size effects to the electronic structure of long graphene nanoribbons using a divide and conquer density functional approach. We find that for hydrogen terminated graphene nanoribbons most of the physical features appearing in the density of states of an infinite graphene nanoribbon are recovered at a length of 40 nm. Nevertheless, even for the longest systems considered (72 nm long) pronounced edge effects appear in the vicinity of the Fermi energy. The wei...

  6. Animal evolution

    DEFF Research Database (Denmark)

    Nielsen, Claus

    This book provides a comprehensive analysis of evolution in the animal kingdom. It reviews the classical, morphological information from structure and embryology, as well as the new data gained from studies using immune stainings of nerves and muscles and blastomere markings, which makes it possi......This book provides a comprehensive analysis of evolution in the animal kingdom. It reviews the classical, morphological information from structure and embryology, as well as the new data gained from studies using immune stainings of nerves and muscles and blastomere markings, which makes...

  7. Emergent properties of patch shapes affect edge permeability to animals.

    Directory of Open Access Journals (Sweden)

    Vilis O Nams

    Full Text Available Animal travel between habitat patches affects populations, communities and ecosystems. There are three levels of organization of edge properties, and each of these can affect animals. At the lowest level are the different habitats on each side of an edge, then there is the edge itself, and finally, at the highest level of organization, is the geometry or structure of the edge. This study used computer simulations to (1 find out whether effects of edge shapes on animal behavior can arise as emergent properties solely due to reactions to edges in general, without the animals reacting to the shapes of the edges, and to (2 generate predictions to allow field and experimental studies to test mechanisms of edge shape response. Individual animals were modeled traveling inside a habitat patch that had different kinds of edge shapes (convex, concave and straight. When animals responded edges of patches, this created an emergent property of responding to the shape of the edge. The response was mostly to absolute width of the shapes, and not the narrowness of them. When animals were attracted to edges, then they tended to collect in convexities and disperse from concavities, and the opposite happened when animals avoided edges. Most of the responses occurred within a distance of 40% of the perceptual range from the tip of the shapes. Predictions were produced for directionality at various locations and combinations of treatments, to be used for testing edge behavior mechanisms. These results suggest that edge shapes tend to either concentrate or disperse animals, simply because the animals are either attracted to or avoid edges, with an effect as great as 3 times the normal density. Thus edge shape could affect processes like pollination, seed predation and dispersal and predator abundance.

  8. Cooled gas turbine blade edge flow analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mendonca, Marcio Teixeira de [Instituto Tecnologico de Aeronautica, Divisao de Engenharia Mecanica Aeronautica ITA/IEM, Sao Jose dos Campos, SP (Brazil)], e-mail: marcio@ita.br

    2010-07-01

    The flow on the rotating blades of a turbine is unsteady due to the wake of the stator blade row upstream. This unsteadiness is a source of losses and complex flow structures on the rotor blade due to the variation on the turbulence levels and location of the boundary layer laminar to turbulent transition. Convective cooled blades often time have cooling air ejected at the trailing edge right at the blade wake. The present investigation presents an analysis of a canonical flow consistent with the flow topology found at the trailing edge of a gas turbine blade with coolant ejection. A hydrodynamic stability analysis is performed for the combined wake and jet velocity profiles given by a gaussian distribution representing the turbulent rms wake and a laminar jet superposed. The growth rate of any instability found on the flow is an indication of faster mixing, resulting in a reduction on the wake velocity defect and consequently on the complexity associated with it. The results show that increasing the Mach number or the three-dimensionality of the disturbances result in a reduction of the amplification rate. When the flow at the trailing edge is modified by a jet, the amplification rates are lower, but the range of unstable stream wise wavenumbers is larger. (author)

  9. The edge plasma and divertor in TIBER

    Energy Technology Data Exchange (ETDEWEB)

    Barr, W.L.

    1987-10-16

    An open divertor configuration has been adopted for TIBER. Most recent designs, including DIII-D, NET and CIT use open configurations and rely on a dense edge plasma to shield the plasma from the gas produced at the neutralizer plate. Experiments on ASDEX, PDX, D-III, and recently on DIII-D have shown that a dense edge plasma can be produced by re-ionizing most of the gas produced at the plate. This high recycling mode allows a large flux of particles to carry the heat to the plate, so that the mean energy per particle can be low. Erosion of the plate can be greatly reduced if the average impact energy of the ions at the plate can be reduced to near or below the threshold for sputtering of the plate material. The present configuration allows part of the flux of edge plasma ions to be neutralized at the entrance to the pumping duct so that helium is pumped as well as hydrogen. 7 refs., 3 figs.

  10. The EDGE-CALIFA Survey: Interferometric Observations of 126 Galaxies with CARMA

    Science.gov (United States)

    Bolatto, Alberto D.; Wong, Tony; Utomo, Dyas; Blitz, Leo; Vogel, Stuart N.; Sánchez, Sebastián F.; Barrera-Ballesteros, Jorge; Cao, Yixian; Colombo, Dario; Dannerbauer, Helmut; García-Benito, Rubén; Herrera-Camus, Rodrigo; Husemann, Bernd; Kalinova, Veselina; Leroy, Adam K.; Leung, Gigi; Levy, Rebecca C.; Mast, Damián; Ostriker, Eve; Rosolowsky, Erik; Sandstrom, Karin M.; Teuben, Peter; van de Ven, Glenn; Walter, Fabian

    2017-09-01

    We present interferometric CO observations, made with the Combined Array for Millimeter-wave Astronomy (CARMA) interferometer, of galaxies from the Extragalactic Database for Galaxy Evolution survey (EDGE). These galaxies are selected from the Calar Alto Legacy Integral Field Area (CALIFA) sample, mapped with optical integral field spectroscopy. EDGE provides good-quality CO data (3σ sensitivity {{{Σ }}}{mol}˜ 11 {M}⊙ {{pc}}-2 before inclination correction, resolution ˜1.4 kpc) for 126 galaxies, constituting the largest interferometric CO survey of galaxies in the nearby universe. We describe the survey and data characteristics and products, then present initial science results. We find that the exponential scale lengths of the molecular, stellar, and star-forming disks are approximately equal, and galaxies that are more compact in molecular gas than in stars tend to show signs of interaction. We characterize the molecular-to-stellar ratio as a function of Hubble type and stellar mass and present preliminary results on the resolved relations between the molecular gas, stars, and star-formation rate. We then discuss the dependence of the resolved molecular depletion time on stellar surface density, nebular extinction, and gas metallicity. EDGE provides a key data set to address outstanding topics regarding gas and its role in star formation and galaxy evolution, which will be publicly available on completion of the quality assessment.

  11. Urbanization impacts on mammals across urban-forest edges and a predictive model of edge effects.

    Science.gov (United States)

    Villaseñor, Nélida R; Driscoll, Don A; Escobar, Martín A H; Gibbons, Philip; Lindenmayer, David B

    2014-01-01

    With accelerating rates of urbanization worldwide, a better understanding of ecological processes at the wildland-urban interface is critical to conserve biodiversity. We explored the effects of high and low-density housing developments on forest-dwelling mammals. Based on habitat characteristics, we expected a gradual decline in species abundance across forest-urban edges and an increased decline rate in higher contrast edges. We surveyed arboreal mammals in sites of high and low housing density along 600 m transects that spanned urban areas and areas turn on adjacent native forest. We also surveyed forest controls to test whether edge effects extended beyond our edge transects. We fitted models describing richness, total abundance and individual species abundance. Low-density housing developments provided suitable habitat for most arboreal mammals. In contrast, high-density housing developments had lower species richness, total abundance and individual species abundance, but supported the highest abundances of an urban adapter (Trichosurus vulpecula). We did not find the predicted gradual decline in species abundance. Of four species analysed, three exhibited no response to the proximity of urban boundaries, but spilled over into adjacent urban habitat to differing extents. One species (Petaurus australis) had an extended negative response to urban boundaries, suggesting that urban development has impacts beyond 300 m into adjacent forest. Our empirical work demonstrates that high-density housing developments have negative effects on both community and species level responses, except for one urban adapter. We developed a new predictive model of edge effects based on our results and the literature. To predict animal responses across edges, our framework integrates for first time: (1) habitat quality/preference, (2) species response with the proximity to the adjacent habitat, and (3) spillover extent/sensitivity to adjacent habitat boundaries. This framework will

  12. Urbanization impacts on mammals across urban-forest edges and a predictive model of edge effects.

    Directory of Open Access Journals (Sweden)

    Nélida R Villaseñor

    Full Text Available With accelerating rates of urbanization worldwide, a better understanding of ecological processes at the wildland-urban interface is critical to conserve biodiversity. We explored the effects of high and low-density housing developments on forest-dwelling mammals. Based on habitat characteristics, we expected a gradual decline in species abundance across forest-urban edges and an increased decline rate in higher contrast edges. We surveyed arboreal mammals in sites of high and low housing density along 600 m transects that spanned urban areas and areas turn on adjacent native forest. We also surveyed forest controls to test whether edge effects extended beyond our edge transects. We fitted models describing richness, total abundance and individual species abundance. Low-density housing developments provided suitable habitat for most arboreal mammals. In contrast, high-density housing developments had lower species richness, total abundance and individual species abundance, but supported the highest abundances of an urban adapter (Trichosurus vulpecula. We did not find the predicted gradual decline in species abundance. Of four species analysed, three exhibited no response to the proximity of urban boundaries, but spilled over into adjacent urban habitat to differing extents. One species (Petaurus australis had an extended negative response to urban boundaries, suggesting that urban development has impacts beyond 300 m into adjacent forest. Our empirical work demonstrates that high-density housing developments have negative effects on both community and species level responses, except for one urban adapter. We developed a new predictive model of edge effects based on our results and the literature. To predict animal responses across edges, our framework integrates for first time: (1 habitat quality/preference, (2 species response with the proximity to the adjacent habitat, and (3 spillover extent/sensitivity to adjacent habitat boundaries. This

  13. Virulence evolution at the front line of spreading epidemics.

    Science.gov (United States)

    Griette, Quentin; Raoul, Gaël; Gandon, Sylvain

    2015-11-01

    Understanding and predicting the spatial spread of emerging pathogens is a major challenge for the public health management of infectious diseases. Theoretical epidemiology shows that the speed of an epidemic is governed by the life-history characteristics of the pathogen and its ability to disperse. Rapid evolution of these traits during the invasion may thus affect the speed of epidemics. Here we study the influence of virulence evolution on the spatial spread of an epidemic. At the edge of the invasion front, we show that more virulent and transmissible genotypes are expected to win the competition with other pathogens. Behind the front line, however, more prudent exploitation strategies outcompete virulent pathogens. Crucially, even when the presence of the virulent mutant is limited to the edge of the front, the invasion speed can be dramatically altered by pathogen evolution. We support our analysis with individual-based simulations and we discuss the additional effects of demographic stochasticity taking place at the front line on virulence evolution. We confirm that an increase of virulence can occur at the front, but only if the carrying capacity of the invading pathogen is large enough. These results are discussed in the light of recent empirical studies examining virulence evolution at the edge of spreading epidemics. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  14. Representing Evolution

    DEFF Research Database (Denmark)

    Hedin, Gry

    2012-01-01

    . This article discusses Willumsen's etching in the context of evolutionary theory, arguing that Willumsen is a rare example of an artist who not only let the theory of evolution fuel his artistic imagination, but also concerned himself with a core issue of the theory, namely to what extent it could be applied...

  15. Accepting evolution.

    Science.gov (United States)

    Chinsamy, Anusuya; Plagányi, Eva

    2008-01-01

    Poor public perceptions and understanding of evolution are not unique to the developed and more industrialized nations of the world. International resistance to the science of evolutionary biology appears to be driven by both proponents of intelligent design and perceived incompatibilities between evolution and a diversity of religious faiths. We assessed the success of a first-year evolution course at the University of Cape Town and discovered no statistically significant change in the views of students before the evolution course and thereafter, for questions that challenged religious ideologies about creation, biodiversity, and intelligent design. Given that students only appreciably changed their views when presented with "facts," we suggest that teaching approaches that focus on providing examples of experimental evolutionary studies, and a strong emphasis on the scientific method of inquiry, are likely to achieve greater success. This study also reiterates the importance of engaging with students' prior conceptions, and makes suggestions for improving an understanding and appreciation of evolutionary biology in countries such as South Africa with an inadequate secondary science education system, and a dire lack of public engagement with issues in science.

  16. Greening Evolution

    African Journals Online (AJOL)

    Administrator

    African Journal of Environmental Science and Technology Vol. ... Greening Evolution. The second week in July marks the occasion of an extraordinary conference entitled "Future Trends in Genetics and. Biotechnology for Safe Environment," sponsored by the ... For example, the information presented in Figure 2 shows.

  17. The use of edge habitats by commuting and foraging bats

    OpenAIRE

    Verboom, B.

    1998-01-01

    Travelling routes and foraging areas of many bat species are mainly along edge habitats, such as treelines, hedgerows, forest edges, and canal banks. This thesis deals with the effects of density, configuration, and structural features of edge habitats on the occurrence of bats. Four hypothetical functions of edge habitats for bats were studied: foraging areas, shelter from wind, shelter from avian predators, and acoustical landmarks.

    Both wind and food abundance we...

  18. Enabling Colloidal Synthesis of Edge-Oriented MoS2 with Expanded Interlayer Spacing for Enhanced HER Catalysis.

    Science.gov (United States)

    Sun, Yugang; Alimohammadi, Farbod; Zhang, Dongtang; Guo, Guangsheng

    2017-03-08

    By selectively promoting heterogeneous nucleation/growth of MoS2 on graphene monolayer sheets, edge-oriented (EO) MoS2 nanosheets with expanded interlayer spacing (∼9.4 Å) supported on reduced graphene oxide (rGO) sheets were successfully synthesized through colloidal chemistry, showing the promise in low-cost and large-scale production. The number and edge length of MoS2 nanosheets per area of graphene sheets were tuned by controlling the reaction time in the microwave-assisted solvothermal reduction of ammonium tetrathiomolybdate [(NH4)2MoS4] in dimethylformamide. The edge-oriented and interlayer-expanded (EO&IE) MoS2/rGO exhibited significantly improved catalytic activity toward hydrogen evolution reaction (HER) in terms of larger current density, lower Tafel slope, and lower charge transfer resistance compared to the corresponding interlayer-expanded MoS2 sheets without edge-oriented geometry, highlighting the importance of synergistic effect between edge-oriented geometry and interlayer expansion on determining HER activity of MoS2 nanosheets. Quantitative analysis clearly shows the linear dependence of current density on the edge length of MoS2 nanosheets.

  19. Canopy gap edge determination and the importance of gap edges for plant diversity

    Directory of Open Access Journals (Sweden)

    D. Salvador-Van Eysenrode

    2002-01-01

    Full Text Available Canopy gaps, i.e. openings in the forest cover caused by the fall of structural elements, are considered to be important for the maintenance of diversity and for the forest cycle. A gap can be considered as a young forest patch in the forest matrix, composed of interior surrounded by an edge, both enclosed by a perimeter. Much of the attention has been focused on the gap interior. However, at gap edges the spectrum of regeneration opportunities for plants may be larger than in the interior. Although definitions of gap are still discussed, any definition can describe it in an acceptable way, if justified, but defining edges is complicated and appropriate descriptors should be used. A method to determine gap interior and edge, using light as a descriptor, is presented with an example of gaps from a beech forest (Fagus sylvatica in Belgium. Also, the relevance and implications of gap edges for plant diversity and calculation of forest turnover is discussed.

  20. Atomic scale structures of interfaces between kaolinite edges and water

    NARCIS (Netherlands)

    Liu, X.; Lu, X.; Wang, R.; Meijer, E.J.; Zhou, H.; He, H.

    2012-01-01

    This paper reports the atomic scale structures of kaolinite edge surfaces in contact with water. The commonly occurring edge surfaces are investigated (i.e. (0 1 0) and (1 1 0)) by using first principles molecular dynamics (FPMD) technique. For (1 1 0)-type edge surface, there are two different

  1. The use of edge habitats by commuting and foraging bats

    NARCIS (Netherlands)

    Verboom, B.

    1998-01-01

    Travelling routes and foraging areas of many bat species are mainly along edge habitats, such as treelines, hedgerows, forest edges, and canal banks. This thesis deals with the effects of density, configuration, and structural features of edge habitats on the occurrence of bats. Four

  2. Roads as edges: Effects on birds in forested landscapes

    Science.gov (United States)

    Yvette K. Ortega; David E. Capen

    2002-01-01

    Numerous studies have documented that forest edges affect habitat use and reproductive success of forest birds, but few studies have considered edges created by narrow breaks in the forest canopy. We compared predation rates on artificial nests placed within forest habitat along edge transects, 10 m from unpaved roads, and along interior transects, 300 m from forest-...

  3. The effect of defocus on edge contrast sensitivity

    NARCIS (Netherlands)

    Jansonius, NM; Kooijman, AC

    The effect of optical blur (defocus) on edge contrast sensitivity was studied. Edge contrast sensitivity detoriates with fairly small amounts of blur (similar to 0.5 D) and is roughly reduced by half for each dioptre of blur. The effect of blur on edge contrast sensitivity equals the effect of blur

  4. Edge-based correlation image registration for multispectral imaging

    Science.gov (United States)

    Nandy, Prabal [Albuquerque, NM

    2009-11-17

    Registration information for images of a common target obtained from a plurality of different spectral bands can be obtained by combining edge detection and phase correlation. The images are edge-filtered, and pairs of the edge-filtered images are then phase correlated to produce phase correlation images. The registration information can be determined based on these phase correlation images.

  5. Meltwater Evolution during Defrosting on Superhydrophobic Surfaces.

    Science.gov (United States)

    Chu, Fuqiang; Wu, Xiaomin; Wang, Lingli

    2017-12-19

    Defrosting is essential for removing frost from engineering surfaces, but some fundamental issues are still unclear, especially for defrosting on superhydrophobic surfaces. Here, defrosting experiments on prepared superhydrophobic surfaces were conducted along with the investigation on meltwater evolution characteristics. According to the experiments, the typical meltwater evolution process on superhydrophobic surfaces can be divided into two stages: dewetting by edge curling and dewetting by shrinkage. The edge curling of a meltwater film is a distinct phenomenon and has been first reported in this work. Profiting from the ultralow adhesion of the superhydrophobic surface, edge curling is mainly attributed to two unbalanced forces (one at the interface between the ice slurry layer and pure water layer and the other in the triple phase line area) acting on the layered meltwater film. During the multi-meltwater evolution process, the nonbreaking of chained droplets on superhydrophobic surfaces is also an interesting phenomenon, which is controlled by the interaction between the surface tension and the retentive force because of contact angle hysteresis. An approximate criterion was then developed to explain and determine the status of chained droplets, and experimental data from various surfaces have validated the effectiveness of this criterion. This work may deepen the understanding of defrosting on superhydrophobic surfaces and promote antifrosting/icing applications in engineering.

  6. Determination of the calcium species in coal chars by Ca K-edge XANES analysis

    Science.gov (United States)

    Liu, Li-Juan; Liu, Hui-Jun; Cui, Ming-Qi; Hu, Yong-Feng; Zheng, Lei; Zhao, Yi-Dong; Ma, Chen-Yan; Xi, Shi-Bo; Yang, Dong-Liang; Guo, Zhi-Ying; Wang, Jie

    2013-02-01

    Ca-based additives have been widely used as a sulfur adsorbent during coal pyrolysis and gasification. The Ca speciation and evolution during the pyrolysis of coal with Ca additives have attracted great attention. In this paper, Ca species in the coal chars prepared from the pyrolysis of Ca(OH)2 or CaCO3-added coals are studied by using Ca K-edge X-ray absorption near-edge structural spectroscopy. The results demonstrate that Ca(OH)2, CaSO4, CaS and CaO coexist in the Ca(OH)2-added chars, while Ca(OH)2 and CaSO4 are the main species in the Ca(OH)2-added chars. Besides, a carboxyl-bound Ca is also formed during both the pyrolysis for the Ca(OH)2-added and the CaCO3-added coals. A detailed discussion about the Ca speciation is given.

  7. Ant-lepidopteran associations along African forest edges

    Science.gov (United States)

    Dejean, Alain; Azémar, Frédéric; Libert, Michel; Compin, Arthur; Hérault, Bruno; Orivel, Jérôme; Bouyer, Thierry; Corbara, Bruno

    2017-02-01

    Working along forest edges, we aimed to determine how some caterpillars can co-exist with territorially dominant arboreal ants (TDAAs) in tropical Africa. We recorded caterpillars from 22 lepidopteran species living in the presence of five TDAA species. Among the defoliator and/or nectarivorous caterpillars that live on tree foliage, the Pyralidae and Nymphalidae use their silk to protect themselves from ant attacks. The Notodontidae and lycaenid Polyommatinae and Theclinae live in direct contact with ants; the Theclinae even reward ants with abundant secretions from their Newcomer gland. Lichen feeders (lycaenid; Poritiinae), protected by long bristles, also live among ants. Some lycaenid Miletinae caterpillars feed on ant-attended membracids, including in the shelters where the ants attend them; Lachnocnema caterpillars use their forelegs to obtain trophallaxis from their host ants. Caterpillars from other species live inside weaver ant nests. Those of the genus Euliphyra (Miletinae) feed on ant prey and brood and can obtain trophallaxis, while those from an Eberidae species only prey on host ant eggs. Eublemma albifascia (Erebidae) caterpillars use their thoracic legs to obtain trophallaxis and trophic eggs from ants. Through transfer bioassays of last instars, we noted that herbivorous caterpillars living in contact with ants were always accepted by alien conspecific ants; this is likely due to an intrinsic appeasing odor. Yet, caterpillars living in ant shelters or ant nests probably acquire cues from their host colonies because they were considered aliens and killed. We conclude that co-evolution with ants occurred similarly in the Heterocera and Rhopalocera.

  8. Ant-lepidopteran associations along African forest edges.

    Science.gov (United States)

    Dejean, Alain; Azémar, Frédéric; Libert, Michel; Compin, Arthur; Hérault, Bruno; Orivel, Jérôme; Bouyer, Thierry; Corbara, Bruno

    2017-02-01

    Working along forest edges, we aimed to determine how some caterpillars can co-exist with territorially dominant arboreal ants (TDAAs) in tropical Africa. We recorded caterpillars from 22 lepidopteran species living in the presence of five TDAA species. Among the defoliator and/or nectarivorous caterpillars that live on tree foliage, the Pyralidae and Nymphalidae use their silk to protect themselves from ant attacks. The Notodontidae and lycaenid Polyommatinae and Theclinae live in direct contact with ants; the Theclinae even reward ants with abundant secretions from their Newcomer gland. Lichen feeders (lycaenid; Poritiinae), protected by long bristles, also live among ants. Some lycaenid Miletinae caterpillars feed on ant-attended membracids, including in the shelters where the ants attend them; Lachnocnema caterpillars use their forelegs to obtain trophallaxis from their host ants. Caterpillars from other species live inside weaver ant nests. Those of the genus Euliphyra (Miletinae) feed on ant prey and brood and can obtain trophallaxis, while those from an Eberidae species only prey on host ant eggs. Eublemma albifascia (Erebidae) caterpillars use their thoracic legs to obtain trophallaxis and trophic eggs from ants. Through transfer bioassays of last instars, we noted that herbivorous caterpillars living in contact with ants were always accepted by alien conspecific ants; this is likely due to an intrinsic appeasing odor. Yet, caterpillars living in ant shelters or ant nests probably acquire cues from their host colonies because they were considered aliens and killed. We conclude that co-evolution with ants occurred similarly in the Heterocera and Rhopalocera.

  9. Climate Data Homogenization Using Edge Detection Algorithms

    Science.gov (United States)

    Hammann, A. C.; Rennermalm, A. K.

    2015-12-01

    The problem of climate data homogenization has predominantly been addressed by testing the likelihood of one or more breaks inserted into a given time series and modeling the mean to be stationary in between the breaks. We recast the same problem in a slightly different form: that of detecting step-like changes in noisy data, and observe that this problem has spawned a large number of approaches to its solution as the "edge detection" problem in image processing. With respect to climate data, we ask the question: How can we optimally separate step-like from smoothly-varying low-frequency signals? We study the hypothesis that the edge-detection approach makes better use of all information contained in the time series than the "traditional" approach (e.g. Caussinus and Mestre, 2004), which we base on several observations. 1) The traditional formulation of the problem reduces the available information from the outset to that contained in the test statistic. 2) The criterion of local steepness of the low-frequency variability, while at least hypothetically useful, is ignored. 3) The practice of using monthly data corresponds, mathematically, to applying a moving average filter (to reduce noise) and subsequent subsampling of the result; this subsampling reduces the amount of available information beyond what is necessary for noise reduction. Most importantly, the tradeoff between noise reduction (better with filters with wide support in the time domain) and localization of detected changes (better with filters with narrow support) is expressed in the well-known uncertainty principle and can be addressed optimally within a time-frequency framework. Unsurprisingly, a large number of edge-detection algorithms have been proposed that make use of wavelet decompositions and similar techniques. We are developing this framework in part to be applied to a particular set of climate data from Greenland; we will present results from this application as well as from tests with

  10. Structural Stability of Functionalized Silicene Nanoribbons with Normal, Reconstructed, and Hybrid Edges

    OpenAIRE

    Sadegh Mehdi Aghaei; Ingrid Torres; Irene Calizo

    2016-01-01

    Silicene, a novel graphene-like material, has attracted a significant attention because of its potential applications for nanoelectronics. In this paper, we have theoretically investigated the structural stability of edge-hydrogenated and edge-fluorinated silicene nanoribbons (SiNRs) via first-principles calculations. Various edge forms of SiNRs including armchair edge, zigzag edge, Klein edge, reconstructed Klein edge, reconstructed pentagon-heptagon edge, and hybrid edges have been consider...

  11. Whispers from the Edge of Physics

    Science.gov (United States)

    Andersson, Nils

    2017-09-01

    Neutron stars involve extreme physics which is difficult (perhaps impossible) to explore in laboratory experiments. We have to turn to astrophysical observations, and try to extract information from the entire range of the electromagnetic spectrum. In addition, neutron stars may radiate gravitational waves through a range of scenarios. This brief summary outlines some of the main ideas, focussing on what we do and do not know, and the challenges involved in trying to catch these faint whispers from the very edge of physics are described.

  12. Refining Nodes and Edges of State Machines

    DEFF Research Database (Denmark)

    Hallerstede, Stefan; Snook, Colin

    2011-01-01

    State machines are hierarchical automata that are widely used to structure complex behavioural specifications. We develop two notions of refinement of state machines, node refinement and edge refinement. We compare the two notions by means of examples and argue that, by adopting simple convention...... refinement theory and UML-B state machine refinement influences the style of node refinement. Hence we propose a method with direct proof of state machine refinement avoiding the detour via Event-B that is needed by UML-B....

  13. The Reconstruction Conjecture and Edge Ideals

    Science.gov (United States)

    2008-01-01

    Given a monomial ideal I in R = k[x1, . . . , xn], we define the multigraded Betti numbers i,b of I in terms of a multigraded minimal free resolution...5.5]). We will use Hochster’s formula from Stanley–Reisner theory to study the multigraded Betti numbers of the edge ideal of a graph. We will prove...Chapter 5]), the multigraded Betti number i,b of R/I can be computed via the reduced simplicial homology of certain subcomplexes of : i,b = i,B := dimk

  14. Bending energy of buckled edge dislocations

    Science.gov (United States)

    Kupferman, Raz

    2017-12-01

    The study of elastic membranes carrying topological defects has a longstanding history, going back at least to the 1950s. When allowed to buckle in three-dimensional space, membranes with defects can totally relieve their in-plane strain, remaining with a bending energy, whose rigidity modulus is small compared to the stretching modulus. In this paper we study membranes with a single edge dislocation. We prove that the minimum bending energy associated with strain-free configurations diverges logarithmically with the size of the system.

  15. Laser Surface Hardening of Groove Edges

    Science.gov (United States)

    Hussain, A.; Hamdani, A. H.; Akhter, R.; Aslam, M.

    2013-06-01

    Surface hardening of groove-edges made of 3Cr13 Stainless Steel has been carried out using 500 W CO2 laser with a rectangular beam of 2.5×3 mm2. The processing speed was varied from 150-500 mm/min. It was seen that the hardened depth increases with increase in laser interaction time. A maximum hardened depth of around 1mm was achieved. The microhardness of the transformed zone was 2.5 times the hardness of base metal. The XRD's and microstructural analysis were also reported.

  16. Orientations of infinite graphs with prescribed edge-connectivity

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2016-01-01

    We prove a decomposition result for locally finite graphs which can be used to extend results on edge-connectivity from finite to infinite graphs. It implies that every 4k-edge-connected graph G contains an immersion of some finite 2k-edge-connected Eulerian graph containing any prescribed vertex...... set (while planar graphs show that G need not containa subdivision of a simple finite graph of large edge-connectivity). Also, every 8k-edge connected infinite graph has a k-arc-connected orientation, as conjectured in 1989....

  17. Three Dimensional Digital Image Processing using Edge Detectors

    Directory of Open Access Journals (Sweden)

    John Schmeelk

    2005-11-01

    Full Text Available This paper provides an introduction to three dimensional image edge detection and its relationship to partial derivatives, convolutions and wavelets. We are especially addressing the notion of edge detection because it has far reaching applications in all areas of research to include medical research. A patient can be diagnosed as having an aneurysm by studying an angiogram. An angiogram is the visual view of the blood vessels whereby the edges are highlighted through the implementation of edge detectors. This process is completed through convolution, wavelets and matrix techniques. Some illustrations included will be vertical, horizontal, Sobel and wavelet edge detectors.

  18. Magnetic edge states and magnetotransport in graphene antidot barriers

    DEFF Research Database (Denmark)

    Thomsen, M. R.; Power, Stephen; Jauho, Antti-Pekka

    2016-01-01

    for antidots smaller than the magnetic length and demonstrate the presence of magnetic edge states, which are localized states on the periphery of the antidots due to successive reflections on the antidot edge in the presence of a magnetic field. We show that these states are robust against variations...... in lattice configuration and antidot edge chirality. Moreover, we calculate the transmittance of disordered GABs and find that magnetic edge states survive a moderate degree of disorder. Due to the long phase-coherence length in graphene and the robustness of these states, we expect magnetic edge states...

  19. Graph Edge Coloring Vizing's Theorem and Goldberg's Conjecture

    CERN Document Server

    Stiebitz, Michael; Toft, Bjarne; Favrholdt, Lene M

    2012-01-01

    Features recent advances and new applications in graph edge coloring Reviewing recent advances in the Edge Coloring Problem, Graph Edge Coloring: Vizing's Theorem and Goldberg's Conjecture provides an overview of the current state of the science, explaining the interconnections among the results obtained from important graph theory studies. The authors introduce many new improved proofs of known results to identify and point to possible solutions for open problems in edge coloring. The book begins with an introduction to graph theory and the concept of edge coloring. Subsequent chapters explor

  20. Aerodynamic Analysis of Trailing Edge Enlarged Wind Turbine Airfoils

    DEFF Research Database (Denmark)

    Xu, Haoran; Shen, Wen Zhong; Zhu, Wei Jun

    2014-01-01

    The aerodynamic performance of blunt trailing edge airfoils generated from the DU- 91-W2-250, DU-97-W-300 and DU-96-W-350 airfoils by enlarging the thickness of trailing edge symmetrically from the location of maximum thickness to chord to the trailing edge were analyzed by using CFD and RFOIL...... methods at a chord Reynolds number of 3 × 106. The goal of this study is to analyze the aerodynamic performance of blunt trailing edge airfoils with different thicknesses of trailing edge and maximum thicknesses to chord. The steady results calculated by the fully turbulent k-ω SST, transitional k-ω SST...

  1. Edge-Detected Guided Morphological Filter for Image Sharpening

    Directory of Open Access Journals (Sweden)

    S. Marshall

    2009-02-01

    Full Text Available A new edge-guided morphological filter is proposed to sharpen digital images. This is done by detecting the positions of the edges and then applying a class of morphological filtering. Motivated by the success of threshold decomposition, gradient-based operators are used to detect the locations of the edges. A morphological filter is used to sharpen these detected edges. Experimental results demonstrate that the performance of these detected edge deblurring filters is superior to that of other sharpener-type filters.

  2. Aerodynamic Analysis of Trailing Edge Enlarged Wind Turbine Airfoils

    OpenAIRE

    Xu, Haoran; Shen, Wen Zhong; Zhu, Wei Jun; Yang, Hua; Liu, Chao

    2014-01-01

    The aerodynamic performance of blunt trailing edge airfoils generated from the DU- 91-W2-250, DU-97-W-300 and DU-96-W-350 airfoils by enlarging the thickness of trailing edge symmetrically from the location of maximum thickness to chord to the trailing edge were analyzed by using CFD and RFOIL methods at a chord Reynolds number of 3 × 106. The goal of this study is to analyze the aerodynamic performance of blunt trailing edge airfoils with different thicknesses of trailing edge and maximum th...

  3. Green's function asymptotics near the internal edges of spectra of periodic elliptic operators. Spectral edge case

    KAUST Repository

    Kuchment, Peter

    2012-06-21

    Precise asymptotics known for the Green\\'s function of the Laplace operator have found their analogs for periodic elliptic operators of the second order at and below the bottom of the spectrum. Due to the band-gap structure of the spectra of such operators, the question arises whether similar results can be obtained near or at the edges of spectral gaps. As the result of this work shows, this is possible at a spectral edge when the dimension d ≥ 3. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Depth Edge Filtering Using Parameterized Structured Light Imaging.

    Science.gov (United States)

    Zheng, Ziqi; Bae, Seho; Yi, Juneho

    2017-04-03

    This research features parameterized depth edge detection using structured light imaging that exploits a single color stripes pattern and an associated binary stripes pattern. By parameterized depth edge detection, we refer to the detection of all depth edges in a given range of distances with depth difference greater or equal to a specific value. While previous research has not properly dealt with shadow regions, which result in double edges, we effectively remove shadow regions using statistical learning through effective identification of color stripes in the structured light images. We also provide a much simpler control of involved parameters. We have compared the depth edge filtering performance of our method with that of the state-of-the-art method and depth edge detection from the Kinect depth map. Experimental results clearly show that our method finds the desired depth edges most correctly while the other methods cannot.

  5. Zigzag graphene nanoribbon edge reconstruction with Stone-Wales defects

    DEFF Research Database (Denmark)

    Rodrigues, J. N. B.; Gonçalves, P. A. D; Rodrigues, N. F. G.

    2011-01-01

    the edge; at the Dirac points one of these lengths diverges, whereas the other remains finite, of the order of the lattice parameter. We trace this curious effect to the doubling of the unit cell along the edge, brought about by the edge reconstruction. In the presence of a magnetic field, the zero......In this paper, we study zigzag graphene nanoribbons with edges reconstructed with Stone-Wales defects, by means of an empirical (first-neighbor) tight-binding method, with parameters determined by ab initio calculations of very narrow ribbons. We explore the characteristics of the electronic band...... structure with a focus on the nature of edge states. Edge reconstruction allows the appearance of a new type of edge states. They are dispersive, with nonzero amplitudes in both sublattices; furthermore, the amplitudes have two components that decrease with different decay lengths with the distance from...

  6. Using new edges for anomaly detection in computer networks

    Science.gov (United States)

    Neil, Joshua Charles

    2015-05-19

    Creation of new edges in a network may be used as an indication of a potential attack on the network. Historical data of a frequency with which nodes in a network create and receive new edges may be analyzed. Baseline models of behavior among the edges in the network may be established based on the analysis of the historical data. A new edge that deviates from a respective baseline model by more than a predetermined threshold during a time window may be detected. The new edge may be flagged as potentially anomalous when the deviation from the respective baseline model is detected. Probabilities for both new and existing edges may be obtained for all edges in a path or other subgraph. The probabilities may then be combined to obtain a score for the path or other subgraph. A threshold may be obtained by calculating an empirical distribution of the scores under historical conditions.

  7. Using new edges for anomaly detection in computer networks

    Energy Technology Data Exchange (ETDEWEB)

    Neil, Joshua Charles

    2017-07-04

    Creation of new edges in a network may be used as an indication of a potential attack on the network. Historical data of a frequency with which nodes in a network create and receive new edges may be analyzed. Baseline models of behavior among the edges in the network may be established based on the analysis of the historical data. A new edge that deviates from a respective baseline model by more than a predetermined threshold during a time window may be detected. The new edge may be flagged as potentially anomalous when the deviation from the respective baseline model is detected. Probabilities for both new and existing edges may be obtained for all edges in a path or other subgraph. The probabilities may then be combined to obtain a score for the path or other subgraph. A threshold may be obtained by calculating an empirical distribution of the scores under historical conditions.

  8. Spontaneous curling of graphene sheets with reconstructed edges.

    Science.gov (United States)

    Shenoy, Vivek B; Reddy, Chilla Damodara; Zhang, Yong-Wei

    2010-08-24

    Recent microscopy experiments have revealed novel reconstructions of the commonly observed zigzag and armchair edges in graphene. We show that tensile edge stresses at these reconstructed edges lead to large-scale curling of graphene sheets into cylindrical surfaces, in contrast to the warping instabilities predicted for unreconstructed edges. Using atomic-scale simulations and large deformation plate models, we have derived scaling laws for the curvature and strain of the curled sheets in terms of the edge stress, shape, and the bending and stretching moduli. For graphene nanoribbons, we show that tensile edge stress leads to periodic ripples, whose morphologies are distinct from those observed due to thermal fluctuations or thermally generated mismatch strains. Since the electronic properties of graphene can be altered by both curvatures and strain, our work provides a route for potentially fabricating nanoelectronic devices such as sensors or switches that can detect stresses induced by dopants at the edges.

  9. Converging social classes through humanized urban edges

    Science.gov (United States)

    Abuan, M. V.; Galingan, Z. D.

    2017-10-01

    Urban open spaces are created to be used by people. It is a place of convergence and social activity. However, these places have transformed into places of divergence. When spaces become dehumanized, it separates social classes. As a result, underused spaces contribute to urban decay. Particularly an urban edge, the JP Rizal Makati Waterfront Area is the center of this paper. The JP Rizal Makati Waterfront Area is a waterfront development situated along the banks of one of Metro Manila’s major water thoroughfare --- Pasig River. The park and its physical form, urban design and landscape tend to deteriorate over time --- creating a further division of social convergence. Social hostility, crime, negligent maintenance and poor urban design are contributing factors to this sprawling decay in what used to be spaces of bringing people together. Amidst attempts to beautify and renew this portion of Makati City’s edge, the urban area still remains misspent.This paper attempts to re-humanize the waterfront development. It uses the responsive environment design principles to be able to achieve this goal.

  10. Inherited thrombophilia: a double-edged sword.

    Science.gov (United States)

    Middeldorp, Saskia

    2016-12-02

    Inherited thrombophilia is a blood coagulation disorder that increases the risk for venous thromboembolism (VTE). During the last decades, the practice of testing has evolved from testing selected populations, leading to high perceived risks, to broad testing for various conditions that included VTE, arterial thrombosis, and pregnancy complications. Because results of such tests usually do not guide treatment decisions, not testing patients with VTE for inherited thrombophilia is on the "Choosing Wisely" list endorsed by multiple specialty societies, including ASH. Inherited thrombophilia can be regarded a double-edged sword, as despite the rationale not to test, it is still being performed frequently. Another way of seeing inherited thrombophilia as a double-edged sword lies in its 2-sided association with reproduction, both in men and in women. Current areas of research are whether women with inherited thrombophilia and pregnancy complications benefit from anticoagulant therapy with regard to improving the chance of a successful pregnancy. Potential effects of inherited thrombophilia, most notably factor V Leiden, on improved embryo implantation in women and sperm counts in men are intriguing, but are currently poorly understood. © 2016 by The American Society of Hematology. All rights reserved.

  11. Photon Counting Using Edge-Detection Algorithm

    Science.gov (United States)

    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

  12. Chess Evolution Visualization.

    Science.gov (United States)

    Lu, Wei-Li; Wang, Yu-Shuen; Lin, Wen-Chieh

    2014-05-01

    We present a chess visualization to convey the changes in a game over successive generations. It contains a score chart, an evolution graph and a chess board, such that users can understand a game from global to local viewpoints. Unlike current graphical chess tools, which focus only on highlighting pieces that are under attack and require sequential investigation, our visualization shows potential outcomes after a piece is moved and indicates how much tactical advantage the player can have over the opponent. Users can first glance at the score chart to roughly obtain the growth and decline of advantages from both sides, and then examine the position relations and the piece placements, to know how the pieces are controlled and how the strategy works. To achieve this visualization, we compute the decision tree using artificial intelligence to analyze a game, in which each node represents a chess position and each edge connects two positions that are one-move different. We then merge nodes representing the same chess position, and shorten branches where nodes on them contain only two neighbors, in order to achieve readability. During the graph rendering, the nodes containing events such as draws, effective checks and checkmates, are highlighted because they show how a game is ended. As a result, our visualization helps players understand a chess game so that they can efficiently learn strategies and tactics. The presented results, evaluations, and the conducted user studies demonstrate the feasibility of our visualization design.

  13. Strength on cut edge and ground edge glass beams with the failure analysis method

    Directory of Open Access Journals (Sweden)

    Stefano Agnetti

    2013-10-01

    Full Text Available The aim of this work is the study of the effect of the finishing of the edge of glass when it has a structural function. Experimental investigations carried out for glass specimens are presented. Various series of annealed glass beam were tested, with cut edge and with ground edge. The glass specimens are tested in four-point bending performing flaw detection on the tested specimens after failure, in order to determine glass strength. As a result, bending strength values are obtained for each specimen. Determining some physical parameter as the depth of the flaw and the mirror radius of the fracture, after the failure of a glass element, it could be possible to calculate the failure strength of that.The experimental results were analyzed with the LEFM theory and the glass strength was analyzed with a statistical study using two-parameter Weibull distribution fitting quite well the failure stress data. The results obtained constitute a validation of the theoretical models and show the influence of the edge processing on the failure strength of the glass. Furthermore, series with different sizes were tested in order to evaluate the size effect.

  14. Spatially resolving and energy splitting of edge state in zigzag edged triangle graphene quantum dots on Cu(111) surface

    Science.gov (United States)

    Wei, Sheng; Jin, Jing; Wang, Zhongping; Lu, Yan; Wang, Li

    2017-05-01

    The electronic structure of graphene nanoribbons (GNRs) and graphene quantum dots (GQDs) has been predicted to depend sensitively on the crystallographic orientation of their edges. However, direct observation of edge state for triangle graphene quantum dots (TGQDs) has not been verified experimentally. Here we explore, using the scanning tunneling spectroscopy (STS), the zigzag edged electronic property of varisized TGQDs. Predominantly zigzag-edged TGQDs exhibit edge-localized states with the energy splittings of about 0.2-0.3 V when its lateral dimension is less than 7 nm. The measured energy splittings agree with theoretical calculations, and show that these edge states originate from a hybridization effect of the substrate, and not from a magnetic splitting of the edge state.

  15. Experimental And Numerical Study Of CMC Leading Edges In Hypersonic Flows

    Science.gov (United States)

    Kuhn, Markus; Esser, Burkard; Gulhan, Ali; Dalenbring, Mats; Cavagna, Luca

    2011-05-01

    Future transportation concepts aim at high supersonic or hypersonic speeds, where the formerly sharp boundaries between aeronautic and aerospace applications become blurred. One of the major issues involved to high speed flight are extremely high aerothermal loads, which especially appear at the leading edges of the plane’s wings and at sharp edged air intake components of the propulsion system. As classical materials like metals or simple ceramics would thermally and structurally fail here, new materials have to be applied. In this context, lightweight ceramic matrix composites (CMC) seem to be prospective candidates as they are high-temperature resistant and offer low thermal expansion along with high specific strength at elevated temperature levels. A generic leading edge model with a ceramic wing assembly with a sweep back angle of 53° was designed, which allowed for easy leading edge sample integration of different CMC materials. The samples consisted of the materials C/C-SiC (non-oxide), OXIPOL and WHIPOX (both oxide) with a nose radius of 2 mm. In addition, a sharp edged C/C-SiC sample was prepared to investigate the nose radius influence. Overall, 13 thermocouples were installed inside the entire model to measure the temperature evolution at specific locations, whereby 5 thermocouples were placed inside the leading edge sample itself. In addition, non-intrusive techniques were applied for surface temperature measurements: An infrared camera was used to measure the surface temperature distribution and at specific spots, the surface temperature was also measured by pyrometers. Following, the model was investigated in DLR’s arc-heated facility L3K at a total enthalpy of 8.5 MJ/kg, Mach number of 7.8, different angles of attack and varying wing inclination angles. These experiments provide a sound basis for the simulation of aerothermally loaded CMC leading edge structures. Such fluid-structure coupled approaches have been performed by FOI, basing on a

  16. On the edge between tradition and innovation

    DEFF Research Database (Denmark)

    Marchetti, Emanuela; Nandhakumar, Joe

    2011-01-01

    investigate also how external pressure from a network, apparently supporting innovation, may instead create a conflicting system of values, compromising the emergence of a negotiation space and hindering the innovation process. Our study suggests that museum innovation is still unsettled, on the edge between...... tradition and innovation, because it is being negatively affected by a global network claiming to support innovation, but in reality denying a negotiation space and demanding for traditional practices to be preserved. Therefore, according to museum practitioners innovation is hindered by a conflicting...... cannot succeed, if it is not supported by a favourable global network, providing a negotiation space (Law and Callon 1992). Starting from this theory, we analyze the case of two local museums, in order to gain insights into museum innovation and the emerging interplay with traditional practices. We...

  17. Edge instability in incompressible planar active fluids

    Science.gov (United States)

    Nesbitt, David; Pruessner, Gunnar; Lee, Chiu Fan

    2017-12-01

    Interfacial instability is highly relevant to many important biological processes. A key example arises in wound healing experiments, which observe that an epithelial layer with an initially straight edge does not heal uniformly. We consider the phenomenon in the context of active fluids. Improving upon the approximation used by Zimmermann, Basan, and Levine [Eur. Phys. J.: Spec. Top. 223, 1259 (2014), 10.1140/epjst/e2014-02189-7], we perform a linear stability analysis on a two-dimensional incompressible hydrodynamic model of an active fluid with an open interface. We categorize the stability of the model and find that for experimentally relevant parameters, fingering instability is always absent in this minimal model. Our results point to the crucial role of density variation in the fingering instability in tissue regeneration.

  18. Transparent Aluminum Oxide Films by Edge Anodization

    Science.gov (United States)

    Stott, Jonathan; Greenwood, Thomas; Winn, David

    In this paper we present our recent work on manufacturing thin (3 - 5 μm) films of porous aluminum(III) oxide [PAO] using a novel edge-anodization technique. With this modified anodization process, we are able to create transparent PAO films on top of insulating substrates such as glass or plastic. By controlling the processing parameters, the index of refraction of PAO films can be engineered to match the substrate, which gives us a durable reflection-free and scratch-resistant coating over conventional optics or LCD displays. Eventually we hope to create ordered porous aluminum oxide cladding around an optical fiber core, which could have a number of interesting optical properties if the pore spacing can be matched to the wavelength of light in the fiber. This work was funded by Fairfield University startup funding.

  19. Wind turbine trailing edge aerodynamic brakes

    Energy Technology Data Exchange (ETDEWEB)

    Migliore, P G [National Renewable Energy Lab., Golden, CO (United States); Miller, L S [Wichita State Univ., KS (United States). Dept. of Aerospace Engineering; Quandt, G A

    1995-04-01

    Five trailing-edge devices were investigated to determine their potential as wind-turbine aerodynamic brakes, and for power modulation and load alleviation. Several promising configurations were identified. A new device, called the spoiler-flap, appears to be the best alternative. It is a simple device that is effective at all angles of attack. It is not structurally intrusive, and it has the potential for small actuating loads. It is shown that simultaneous achievement of a low lift/drag ratio and high drag is the determinant of device effectiveness, and that these attributes must persist up to an angle of attack of 45{degree}. It is also argued that aerodynamic brakes must be designed for a wind speed of at least 45 m/s (100 mph).

  20. Communication networks for the tactical edge

    Science.gov (United States)

    Evans, Joseph B.; Pennington, Steven G.; Ewy, Benjamin J.

    2017-04-01

    Information at the tactical level is increasingly critical in today's conflicts. The proliferation of commercial tablets and smart phones has created the ability for extensive information sharing at the tactical edge, beyond the traditional tactical voice communications and location information. This is particularly the case in Gray Zone conflicts, in which tactical decision making and actions are intertwined with information sharing and exploitation. Networking of tactical devices is the key to this information sharing. In this work, we detail and analyze two network models at different parts of the Gray Zone spectrum, and explore a number of networking options including Named Data Networking. We also compare networking approaches in a variety of realistic operating environments. Our results show that Named Data Networking is a good match for the disrupted networking environments found in many tactical situations

  1. Ascending aorta diameters measured by echocardiography using both leading edge-to-leading edge and inner edge-to-inner edge conventions in healthy volunteers.

    Science.gov (United States)

    Muraru, Denisa; Maffessanti, Francesco; Kocabay, Gonenc; Peluso, Diletta; Dal Bianco, Lucia; Piasentini, Eleonora; Jose, Seena Padayattil; Iliceto, Sabino; Badano, Luigi P

    2014-04-01

    Reference ranges of ascending aorta diameters (AAoD) for two-dimensional echocardiography (2DE) using inner edge (IE) convention are lacking, preventing the comparison of AAoD measurements by 2DE with those obtained by other imaging modalities. We used harmonic imaging 2DE to prospectively study 218 healthy volunteers (56% women, 42 ± 15 years, 18-80 years). Measurements were performed at the level of aortic root (AoR), sinotubular junction (STJ), and proximal tubular portion (TAo, 1 cm from the STJ) using both leading edge (LE) and IE conventions at end-diastole and end-systole. Feasibility of AAoD measurements between end-diastole and end-systole was similar at AoR and STJ levels, but it was significantly different at TAo level (82 vs. 96%, respectively, P measured using IE convention were similar between genders (17 ± 2, 15 ± 2, and 15 ± 2 mm/m(2), respectively). Corresponding AAoD measured using the LE convention were 18 ± 2, 16 ± 2, and 17 ± 4 mm/m(2), respectively. On average, the end-systolic AAoD measured using LE were 2 mm larger than those performed using IE or at end-diastole. Mean aortic wall thickness was 2.4 ± 0.8 mm. End-diastolic AAoD measured using IE were significantly smaller than those obtained either using LE convention or at end-systole. Gender-specific reference values for AAoD indexed for BSA should be used to identify ascending aorta pathology.

  2. The dynamics of the formation of the edge particle transport barrier at TJ-II

    Science.gov (United States)

    van Milligen, B. Ph.; Pedrosa, M. A.; Hidalgo, C.; Carreras, B. A.; Estrada, T.; Alonso, J. A.; de Pablos, J. L.; Melnikov, A.; Krupnik, L.; Eliseev, L. G.; Perfilov, S. V.

    2011-11-01

    A large set of discharges with both spontaneous and forced confinement transitions at low electron density is studied at the stellarator TJ-II in different magnetic configurations. By means of a Bayesian technique, using reflectometry and interferometry, electron density profiles are reconstructed in the outer half of the plasma. A scanning heavy ion beam probe delivers information on the global evolution of the plasma potential. Langmuir probes are used to measure long-range correlations. Together, a comprehensive picture is obtained of the evolution of various key global plasma profiles and parameters across forward and backward transitions associated with the formation of an edge sheared flow layer. The impact of low-order rationals on the transition is elucidated.

  3. Slope Edge Deformation and Permafrost Dynamics Along the Arctic Shelf Edge, Beaufort Sea, Canada

    Science.gov (United States)

    Paull, C. K.; Dallimore, S.; Caress, D. W.; Gwiazda, R.; Lundsten, E. M.; Anderson, K.; Riedel, M.; Melling, H.

    2015-12-01

    The shelf of the Canadian Beaufort Sea is underlain by relict offshore permafrost that formed in the long intervals of terrestrial exposure during glacial periods. At the shelf edge the permafrost thins rapidly and also warms. This area has a very distinct morphology that we attribute to both the formation and degradation of ice bearing permafrost. Positive relief features include circular to oval shaped topographic mounds, up to 10 m high and ~50 m in diameter which occur at a density of ~6 per km2. Intermixed are circular topographic depressions up to 20 m deep. This topography was investigated using an autonomous underwater vehicle that provides 1 m horizontal resolution bathymetry and chirp profiles, a remotely operated vehicle to document seafloor textures, and sediment cores to sample pore waters. A consistent down-core freshening at rates of 14 to 96 mM Cl- per meter was found in these pore waters near the shelf edge. Downward extrapolation of these trends indicates water with ≤335 mM Cl- should occur at 2.3 to 22.4 m sub-seafloor depths within this shelf edge deformation band. Pore water with 335 mM Cl- or less freezes at -1.4°C. As bottom water temperatures in this area are persistently (<-1.4°C) cold and ground ice was observed in some core samples, we interpret the volume changes associated with mound formation are in part due to pore water freezing. Thermal models (Taylor et al., 2014) predict brackish water along the shelf edge may be sourced in relict permafrost melting under the adjacent continental shelf. Buoyant brackish water is hypothesized to migrate along the base of the relict permafrost, to emerge at the shelf edge and then refreeze when it encounters the colder seafloor. Expansion generated by the formation of ice-bearing permafrost generates the positive relief mounds and ridges. The associated negative relief features may be related to permafrost dynamics also. Permafrost dynamics may have geohazard implications that are unique to the

  4. Modeling of Airfoil Trailing Edge Flap with Immersed Boundary Method

    DEFF Research Database (Denmark)

    Zhu, Wei Jun; Shen, Wen Zhong; Sørensen, Jens Nørkær

    2011-01-01

    The present work considers incompressible flow over a 2D airfoil with a deformable trailing edge. The aerodynamic characteristics of an airfoil with a trailing edge flap is numerically investigated using computational fluid dynamics. A novel hybrid immersed boundary (IB) technique is applied...... to simulate the moving part of the trailing edge. Over the main fixed part of the airfoil the Navier-Stokes (NS) equations are solved using a standard body-fitted finite volume technique whereas the moving trailing edge flap is simulated with the immersed boundary method on a curvilinear mesh. The obtained...... results show that the hybrid approach is an efficient and accurate method for solving turbulent flows past airfoils with a trailing edge flap and flow control using trailing edge flap is an efficient way to regulate the aerodynamic loading on airfoils....

  5. Optimal Scale Edge Detection Utilizing Noise within Images

    Directory of Open Access Journals (Sweden)

    Adnan Khashman

    2003-04-01

    Full Text Available Edge detection techniques have common problems that include poor edge detection in low contrast images, speed of recognition and high computational cost. An efficient solution to the edge detection of objects in low to high contrast images is scale space analysis. However, this approach is time consuming and computationally expensive. These expenses can be marginally reduced if an optimal scale is found in scale space edge detection. This paper presents a new approach to detecting objects within images using noise within the images. The novel idea is based on selecting one optimal scale for the entire image at which scale space edge detection can be applied. The selection of an ideal scale is based on the hypothesis that "the optimal edge detection scale (ideal scale depends on the noise within an image". This paper aims at providing the experimental evidence on the relationship between the optimal scale and the noise within images.

  6. Edge Response and NIIRS Estimates for Commercial Remote Sensing Satellites

    Science.gov (United States)

    Blonski, Slawomir; Ryan, Robert E.; Pagnutti, mary; Stanley, Thomas

    2006-01-01

    Spatial resolution of panchromatic imagery from commercial remote sensing satellites was characterized based on edge response measurements using edge targets and the tilted-edge technique. Relative Edge Response (RER) was estimated as a geometric mean of normalized edge response differences measured in two directions of image pixels at points distanced from the edge by -0.5 and 0.5 of ground sample distance. RER is one of the engineering parameters used in the General Image Quality Equation to provide predictions of imaging system performance expressed in terms of the National Imagery Interpretability Rating Scale (NIIRS). By assuming a plausible range of signal-to-noise ratio and assessing the effects of Modulation Transfer Function compensation, the NIIRS estimates were made and then compared with vendor-provided values and evaluations conducted by the National Geospatial-Intelligence Agency.

  7. Specimen edge effects on bending fatigue of carburized steel

    Science.gov (United States)

    Cohen, R. E.; Matlock, D. K.; Krauss, G.

    1992-10-01

    The effects of specimen geometry on the fatigue behavior of SAE 4320 steel carburized at 927 °C were evaluated with two sets of cantilever bend specimens, one set machined with square edges and one set machined with round edges. The specimens with square edges exhibited a 13% lower fatigue limit. In comparison to the rounded samples, the lower fatigue limit in the square-edged samples was attributed to the presence of a higher volume fraction of retained austenite in the sample corners and a lower surface residual compressive stress. As a result of the differences in residual stress, preferential crack initiation sites existed in the square-edged samples at a location approximately 200 to 900 ώm from the square edge. The implications of this study on laboratory analyses of the bending fatigue performance of carburized gear steels are discussed.

  8. Inducing superconducting correlation in quantum Hall edge states

    Science.gov (United States)

    Lee, Gil-Ho; Huang, Ko-Fan; Efetov, Dmitri K.; Wei, Di S.; Hart, Sean; Taniguchi, Takashi; Watanabe, Kenji; Yacoby, Amir; Kim, Philip

    2017-07-01

    The quantum Hall (QH) effect supports a set of chiral edge states at the boundary of a two-dimensional system. A superconductor (SC) contacting these states can provide correlations of the quasiparticles in the dissipationless edge states. Here we fabricated highly transparent and nanometre-scale SC junctions to graphene. We demonstrate that the QH edge states can couple via superconducting correlations through the SC electrode narrower than the superconducting coherence length. We observe that the chemical potential of the edge state exhibits a sign reversal across the SC electrode. This provides direct evidence of conversion of the incoming electron to the outgoing hole along the chiral edge state, termed crossed Andreev conversion (CAC). We show that CAC can successfully describe the temperature, bias and SC electrode width dependences. This hybrid SC/QH system could provide a novel route to create isolated non-Abelian anyonic zero modes, in resonance with the chiral edge states.

  9. Sensory Organ Like Response of Zigzag Edge Graphene Nanoribbons

    Science.gov (United States)

    Shenoy, Vijay; Bhowmick, Somnath

    2011-03-01

    Using a continuum Dirac theory, we study the density and spin response of zigzag edge terminated graphene ribbons subjected to edge potentials and Zeeman fields. Our analytical calculations of the density and spin responses of the closed system (fixed particle number) to the static edge fields, show a highly nonlinear Weber-Fechner type behavior where the response depends logarithmically on the edge potential. The dependence of the response on the size of the system (e.g.~width of a nanoribbon) is also uncovered. Zigzag edge graphene nanoribbons, therefore, provide a realization of response of organs such as the eye and ear that obey Weber-Fechner law. We validate our analytical results with tight binding calculations. These results are crucial in understanding important effects of electron-electron interactions in graphene nanoribbons such as edge magnetism etc., and also suggest possibilities for device applications of graphene nanoribbons. Work supported by DST, India through MONAMI and Ramanujan grants.

  10. Edge Minority Heating Experiment in Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    S.J. Zweben; J.L. Terry; P. Bonoli; R. Budny; C.S. Chang; C. Fiore; G. Schilling; S. Wukitch; J. Hughes; Y. Lin; R. Perkins; M. Porkolab; the Alcator C-Mod Team

    2005-03-25

    An attempt was made to control global plasma confinement in the Alcator C-Mod tokamak by applying ion cyclotron resonance heating (ICRH) power to the plasma edge in order to deliberately create a minority ion tail loss. In theory, an edge fast ion loss could modify the edge electric field and so stabilize the edge turbulence, which might then reduce the H-mode power threshold or improve the H-mode barrier. However, the experimental result was that edge minority heating resulted in no improvement in the edge plasma parameters or global stored energy, at least at power levels of radio-frequency power is less than or equal to 5.5 MW. A preliminary analysis of these results is presented and some ideas for improvement are discussed.

  11. An improved edge detection algorithm for depth map inpainting

    Science.gov (United States)

    Chen, Weihai; Yue, Haosong; Wang, Jianhua; Wu, Xingming

    2014-04-01

    Three-dimensional (3D) measurement technology has been widely used in many scientific and engineering areas. The emergence of Kinect sensor makes 3D measurement much easier. However the depth map captured by Kinect sensor has some invalid regions, especially at object boundaries. These missing regions should be filled firstly. This paper proposes a depth-assisted edge detection algorithm and improves existing depth map inpainting algorithm using extracted edges. In the proposed algorithm, both color image and raw depth data are used to extract initial edges. Then the edges are optimized and are utilized to assist depth map inpainting. Comparative experiments demonstrate that the proposed edge detection algorithm can extract object boundaries and inhibit non-boundary edges caused by textures on object surfaces. The proposed depth inpainting algorithm can predict missing depth values successfully and has better performance than existing algorithm around object boundaries.

  12. Palm Print Edge Extraction Using Fractional Differential Algorithm

    OpenAIRE

    Chunmei Chi; Feng Gao

    2013-01-01

    Algorithm based on fractional difference was used for the edge extraction of thenar palm print image. Based on fractional order difference function which was deduced from classical fractional differential G-L definition, three filter templates were constructed to extract thenar palm print edge. The experiment results showed that this algorithm can reduce noise and detect rich edge details and has higher SNR than traditional methods.

  13. Integral edge seals for phosphoric acid fuel cells

    Science.gov (United States)

    Granata, Jr., Samuel J. (Inventor); Woodle, Boyd M. (Inventor); Dunyak, Thomas J. (Inventor)

    1992-01-01

    A phosphoric acid fuel cell having integral edge seals formed by an elastomer permeating an outer peripheral band contiguous with the outer peripheral edges of the cathode and anode assemblies and the matrix to form an integral edge seal which is reliable, easy to manufacture and has creep characteristics similar to the anode, cathode and matrix assemblies inboard of the seals to assure good electrical contact throughout the life of the fuel cell.

  14. Terahertz radiation driven chiral edge currents in graphene

    OpenAIRE

    Karch, J.; Drexler, C.; Olbrich, P.; Fehrenbacher, M.; Hirmer, M; Glazov, M. M.; Tarasenko, S. A.; Ivchenko, E. L.; Birkner, B.; Eroms, J.; Weiss, D.; Yakimova, R; Lara-Avila, Samuel; Kubatkin, Sergey; Ostler, M.

    2011-01-01

    We observe photocurrents induced in single-layer graphene samples by illumination of the graphene edges with circularly polarized terahertz radiation at normal incidence. The photocurrent flows along the sample edges and forms a vortex. Its winding direction reverses by switching the light helicity from left to right handed. We demonstrate that the photocurrent stems from the sample edges, which reduce the spatial symmetry and result in an asymmetric scattering of carriers driven by the radia...

  15. Strain-tuning of edge magnetism in zigzag graphene nanoribbons.

    Science.gov (United States)

    Yang, Guang; Li, Baoyue; Zhang, Wei; Ye, Miao; Ma, Tianxing

    2017-09-13

    Using the determinant quantum Monte-Carlo method, we elucidate the strain tuning of edge magnetism in zigzag graphene nanoribbons. Our intensive numerical results show that a relatively weak Coulomb interaction may induce a ferromagnetic-like behaviour with a proper strain, and the edge magnetism can be enhanced greatly as the strain along the zigzag edge increases, which provides another way to control graphene magnetism even at room temperature.

  16. Edge irregular total labellings for graphs of linear size

    DEFF Research Database (Denmark)

    Brandt, Stephan; Rautenbach, D.; Miškuf, J.

    2009-01-01

    As an edge variant of the well-known irregularity strength of a graph G = (V, E) we investigate edge irregular total labellings, i.e. functions f : V ∪ E → {1, 2, ..., k} such that f (u) + f (u v) + f (v) ≠ f (u) + f (u v) + f (v) for every pair of different edges u v, u v ∈ E. The smallest possi...

  17. Design of Tunable Edge Coupled Microstrip Bandpass Filters

    OpenAIRE

    Kaveri, Srinidhi V

    2008-01-01

    This thesis is a study of tunability of edge-coupled filters. Microstrip edge-coupled bandpass filters are planar structures and have advantages such as easy design procedures and simple integration into circuits. Three tuning techniques were implemented. The first technique involved the loading of one open end of each coupled into tunable capacitors. The second technique used a tunable resonator in series with the edge-coupled blocks. The final design made use of tunable feedback sections. A...

  18. An Ultra-Low Power Edge Combining BPSK Transmitter

    Science.gov (United States)

    2013-09-01

    TECHNICAL DOCUMENT 3271 September 2013 An Ultra-Low Power Edge Combining BPSK Transmitter A. Ryu J. Rowland S. Naik...Ultra-Low Power Edge Combining BPSK Transmitter Albert Ryu #1, Jason Rowland #2, Suketu Naik #3 #1, #2 55250, Advanced Integrated Circuit Technology...locked to a ring oscillator (RO), and then multiple phase outputs are combined at the last edge combining/power amplifier (EC/PA) stage. With the

  19. Thought Evolution

    Directory of Open Access Journals (Sweden)

    Shadrikov V.D.

    2015-08-01

    Full Text Available The thought evolution is studied by historical reconstruction method that is based on the propositions of the theory of culturalhistorical determination of the psyche development, and the data of the morphological analysis and child development, and the conception of the psyche neuroontogenesis. The grounds for advisability of protothinking are presented. The protothinking is understood as the use of objective thought in cases of awareness absence. It is shown that protothinking is a form of transition from animal thinking to human speech. The particular attention is paid to the process of the word producing and thought generation in that process. The conditions of word producing as cooccurring acoustic pattern served for though expression are discussed. It is emphasized that a word is produced by a particular person. The historical development of the language and the specificity of this development are pointed out

  20. Mode decomposition evolution equations.

    Science.gov (United States)

    Wang, Yang; Wei, Guo-Wei; Yang, Siyang

    2012-03-01

    Partial differential equation (PDE) based methods have become some of the most powerful tools for exploring the fundamental problems in signal processing, image processing, computer vision, machine vision and artificial intelligence in the past two decades. The advantages of PDE based approaches are that they can be made fully automatic, robust for the analysis of images, videos and high dimensional data. A fundamental question is whether one can use PDEs to perform all the basic tasks in the image processing. If one can devise PDEs to perform full-scale mode decomposition for signals and images, the modes thus generated would be very useful for secondary processing to meet the needs in various types of signal and image processing. Despite of great progress in PDE based image analysis in the past two decades, the basic roles of PDEs in image/signal analysis are only limited to PDE based low-pass filters, and their applications to noise removal, edge detection, segmentation, etc. At present, it is not clear how to construct PDE based methods for full-scale mode decomposition. The above-mentioned limitation of most current PDE based image/signal processing methods is addressed in the proposed work, in which we introduce a family of mode decomposition evolution equations (MoDEEs) for a vast variety of applications. The MoDEEs are constructed as an extension of a PDE based high-pass filter (Europhys. Lett., 59(6): 814, 2002) by using arbitrarily high order PDE based low-pass filters introduced by Wei (IEEE Signal Process. Lett., 6(7): 165, 1999). The use of arbitrarily high order PDEs is essential to the frequency localization in the mode decomposition. Similar to the wavelet transform, the present MoDEEs have a controllable time-frequency localization and allow a perfect reconstruction of the original function. Therefore, the MoDEE operation is also called a PDE transform. However, modes generated from the present approach are in the spatial or time domain and can be

  1. Simulations of Edge Current Driven Kink Modes with BOUT + + code

    Science.gov (United States)

    Li, G. Q.; Xu, X. Q.; Snyder, P. B.; Turnbull, A. D.; Xia, T. Y.; Ma, C. H.; Xi, P. W.

    2013-10-01

    Edge kink modes (or peeling modes) play a key role in the ELMs. The edge kink modes are driven by peak edge current, which comes from the bootstrap current. We calculated sequences of equilibria with different edge current using CORSICA by keeping total current and pressure profile fixed. Based on these equilibria, with the 3-field BOUT + + code, we calculated the MHD instabilities driven by edge current. For linear low-n ideal MHD modes, BOUT + + results agree with GATO results. With the edge current increasing, the dominant modes are changed from high-n ballooning modes to low-n kink modes. The edge current provides also stabilizing effects on high-n ballooning modes. Furthermore, for edge current scan without keeping total current fixed, the increasing edge current can stabilize the high-n ballooning modes and cannot drive kink modes. The diamagnetic effect can stabilize the high-n ballooning modes, but has no effect on the low-n kink modes. Also, the nonlinear behavior of kink modes is analyzed. Work supported by China MOST grant 2013GB111000 and by China NSF grant 10975161. Also performed for USDOE by LLNL under DE-AC52-07NA27344.

  2. Edge detection in digital images using Ant Colony Optimization

    Directory of Open Access Journals (Sweden)

    Marjan Kuchaki Rafsanjani

    2015-11-01

    Full Text Available Ant Colony Optimization (ACO is an optimization algorithm inspired by the behavior of real ant colonies to approximate the solutions of difficult optimization problems. In this paper, ACO is introduced to tackle the image edge detection problem. The proposed approach is based on the distribution of ants on an image; ants try to find possible edges by using a state transition function. Experimental results show that the proposed method compared to standard edge detectors is less sensitive to Gaussian noise and gives finer details and thinner edges when compared to earlier ant-based approaches.

  3. Acoustic analog of monolayer graphene and edge states

    Science.gov (United States)

    Zhong, Wei; Zhang, Xiangdong

    2011-09-01

    Acoustic analog of monolayer graphene has been designed by using silicone rubber spheres of honeycomb lattices embedded in water. The dispersion of the structure has been studied theoretically using the rigorous multiple-scattering method. The energy spectra with the Dirac point have been verified and zigzag edge states have been found in ribbons of the structure, which are analogous to the electronic ones in graphene nanoribbons. The guided modes along the zigzag edge excited by a point source have been numerically demonstrated. The open cavity and “Z” type edge waveguide with 60° corners have also been realized by using such edge states.

  4. Spiraling Edge: Fast Surface Reconstruction from Partially Organized Sample Points

    Energy Technology Data Exchange (ETDEWEB)

    Angel, Edward; Crossno, Patricia

    1999-07-12

    Many applications produce three-dimensional points that must be further processed to generate a surface. Surface reconstruction algorithms that start with a set of unorganized points are extremely time-consuming. Sometimes, however, points are generated such that there is additional information available to the reconstruction algorithm. We present Spiraling Edge, a specialized algorithm for surface reconstruction that is three orders of magnitude faster than algorithms for the general case. In addition to sample point locations, our algorithm starts with normal information and knowledge of each point's neighbors. Our algorithm produces a localized approximation to the surface by creating a star-shaped triangulation between a point and a subset of its nearest neighbors. This surface patch is extended by locally triangulating each of the points along the edge of the patch. As each edge point is triangulated, it is removed from the edge and new edge points along the patch's edge are inserted in its place. The updated edge spirals out over the surface until the edge encounters a surface boundary and stops growing in that direction, or until the edge reduces to a small hole that is filled by the final triangle.

  5. [Edge effect and its impacts on forest ecosystem: a review].

    Science.gov (United States)

    Tian, Chao; Yang, Xin-bing; Liu, Yang

    2011-08-01

    Edge effect is an important concept in ecology and biological conservation, playing an important role in the study of ecological processes such as energy and material flow at ecosystem scale and landscape scale. This paper expatiated the connotation, features, quantitative evaluation (basis of quantitative analysis, strength, impact zone, and models, etc.), and applied aspects of edge effect, summarized the impacts of edge effect on forest ecosystem, analyzed the deficiencies in the study of edge effect, and prospected related research directions, aimed to provide references for forest and protected area management.

  6. Line Edge Detection and Characterization in SEM Images using Wavelets

    Energy Technology Data Exchange (ETDEWEB)

    Sun, W; Romagnoli, J A; Tringe, J W; L?tant, S E; Stroeve, P; Palazoglu, A

    2008-10-07

    Edge characterization has become increasingly important in nanotechnology due to the growing demand for precise nanoscale structure fabrication and assembly. Edge detection is often performed by thresholding the spatial information of a top-down image obtained by Scanning Electron Microscopy (SEM) or other surface characterization techniques. Results are highly dependent on an arbitrary threshold value, which makes it difficult to reveal the nature of the real surface and to compare results among images. In this paper, we present an alternative edge boundary detection technique based on the wavelet framework. Our results indicate that the method facilitates nano-scale edge detection and characterization, by providing a systematic threshold determination step.

  7. Anomalous edge states and the bulk-edge correspondence for periodically-driven two dimensional systems

    DEFF Research Database (Denmark)

    Rudner, Mark Spencer; Lindner, Netanel; Berg, Erez

    2013-01-01

    revealed phenomena that cannot be characterized by analogy to the topological classification framework for static systems. In particular, in driven systems in two dimensions (2D), robust chiral edge states can appear even though the Chern numbers of all the bulk Floquet bands are zero. Here, we elucidate...... the crucial distinctions between static and driven 2D systems, and construct a new topological invariant that yields the correct edge-state structure in the driven case. We provide formulations in both the time and frequency domains, which afford additional insight into the origins of the “anomalous” spectra...... that arise in driven systems. Possibilities for realizing these phenomena in solid-state and cold-atomic systems are discussed....

  8. Design of a Control System for Quality Maintenance on Cutting Edges of Files Production

    Directory of Open Access Journals (Sweden)

    E. Seabra

    2000-01-01

    Full Text Available The file cutting edges are the most important parameter that influence the performance of the filing operation. The practice shows that the most efficient way of generating these cutting edges is by penetration, by blow, of a cutting tool, which creates a plastic deformation on the file body. The penetration depth is probably the most important factor of the final quality of a file. In the existing machines of files manufacturing, this depth is manually adjusted by the operator, using specific mechanism. This means that files are manufactured on an empirical basis, relying on subjective factors, that do not allow to keep constant quality level of the production. In a research work, being developed in the University of Minho, it is intended to eliminate the subjectivity factors by the means of the evolution of the present “all-mechanical” system to a “mechatronic” one. In this paper, which is related with that research work, it presented a study of a round files production machine, regarding the identification, as well as the categorisation, of the operating parameters that affect the cutting edges production. They are, as well, defined and quantified those factors that influence the final quality of a round file.

  9. Simulation of leading edge cavitation on bulb turbine

    Directory of Open Access Journals (Sweden)

    Thaithacha Sudsuansee

    2011-02-01

    Full Text Available Cavitation caused by phases exchange between fluids of large density difference occurs in a region where thepressure of water falls below its vapor pressure. The density of water in a water-vapor contact area decreases dramatically.As a result, the flow in this region is compressible, which affects directly turbulent dissipation structures. Leading edgecavitation is naturally time dependent. Re-entrant jet generated by liquid flow over a cavity is a main actor of cavity shedding.Simulation of unsteady leading edge cavitation flows through a 4-blade runner bulb turbine was performed. Particular attentionwas given to the phenomena of re-entrant jet, cavity shedding, and cavitation vortices in the flow over turbine blade.The Reynolds-Average Navier-Stokes equations with finite volume discretization were used. The calculations were donewith pressure-based algorithms since the flow possesses a wide range of density change and high complexity turbulence.The new formula for dilatation dissipation parameter in k- model was introduced and the turbulent Mach number wascalculated from density of mixture instead. 2-D and 3-D hydrofoils based on both numerical and experimental results accomplisheda validation. The results show that re-entrant jet, shedding of cavity, and cavitation vortices can be captured. Inaddition, this paper also calculates the cycle frequency of torque generated by the runner and vapor area evolution on theblade surface. The cycle frequency varies with cavitation number. At normal operation of this turbine ( = 1 it is found thatboth of them have a frequency of 46 Hertz.

  10. Mechanical basis of morphogenesis and convergent evolution of spiny seashells

    KAUST Repository

    Chirat, R.

    2013-03-25

    Convergent evolution is a phenomenon whereby similar traits evolved independently in not closely related species, and is often interpreted in functional terms. Spines in mollusk seashells are classically interpreted as having repeatedly evolved as a defense in response to shell-crushing predators. Here we consider the morphogenetic process that shapes these structures and underlies their repeated emergence. We develop a mathematical model for spine morphogenesis based on the mechanical interaction between the secreting mantle edge and the calcified shell edge to which the mantle adheres during shell growth. It is demonstrated that a large diversity of spine structures can be accounted for through small variations in control parameters of this natural mechanical process. This physical mechanism suggests that convergent evolution of spines can be understood through a generic morphogenetic process, and provides unique perspectives in understanding the phenotypic evolution of this second largest phylum in the animal kingdom.

  11. Evolution of random catalytic networks

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, S.M. [Santa Fe Inst., NM (United States); Reidys, C.M. [Santa Fe Inst., NM (United States)]|[Los Alamos National Lab., NM (United States)

    1997-06-01

    In this paper the authors investigate the evolution of populations of sequences on a random catalytic network. Sequences are mapped into structures, between which are catalytic interactions that determine their instantaneous fitness. The catalytic network is constructed as a random directed graph. They prove that at certain parameter values, the probability of some relevant subgraphs of this graph, for example cycles without outgoing edges, is maximized. Populations evolving under point mutations realize a comparatively small induced subgraph of the complete catalytic network. They present results which show that populations reliably discover and persist on directed cycles in the catalytic graph, though these may be lost because of stochastic effects, and study the effect of population size on this behavior.

  12. Numerical simulation of flow characteristics behind the aerodynamic performances on an airfoil with leading edge protuberances

    Directory of Open Access Journals (Sweden)

    Ming Zhao

    2017-01-01

    Full Text Available This article presents a numerical investigation of the effects of leading-edge protuberances on airfoil stall and post-stall performance. An improved delayed detached eddy simulation (IDDES method was adopted. As a result, to clarify the effects of ‘bi-periodic’ phenomenon around stall region, it was found that the flow separation at troughs was the main inducement of aerodynamic lift degradation within pre-stall regime and the flow pattern where vortices diverged was predominant. It was also found that the variations in flow patterns led to the gentle stall process. Furthermore, to study the statistical characteristics of unsteady vortex shedding, corresponding spectrum characteristics were also analyzed from another perspective, suggesting that the vortex shedding frequency was higher where vortices converged. Eventually, the improved performances of tubercled airfoil within post-stall regime could be attributed to the strong streamwise vortices generated by the leading-edge protuberances. Deploying the methods of vortex dynamics, the generation and evolution of the streamwise vortices were depicted. It turned out that the primary and secondary vortices were induced by spanwise pressure gradient at airfoil surface; meanwhile, vortex stretching played a key role in primary vortex evolution, which initially enhanced the strength of vortices corresponding to the acceleration of streamwise velocity.

  13. Wisps in the outer edge of the Keeler Gap

    Science.gov (United States)

    Tiscareno, Matthew S.; Arnault, Ethan G.

    2015-11-01

    Superposed upon the relatively smooth outer edge of the Keeler Gap are a system of "wisps," which appear to be ring material protruding inward into the gap, usually with a sharp trailing edge and a smooth gradation back to the background edge location on the leading side (Porco et al. 2005, Science). The radial amplitude of wisps is usually 0.5 to 1 km, and their azimuthal extent is approximately a degree of longitude (~2400 km). Wisps are likely caused by an interplay between Daphnis (and perhaps other moons) and embedded moonlets within the ring, though the details remain unclear.Aside from the wisps, the Keeler Gap outer edge is the only one of the five sharp edges in the outer part of Saturn's A ring that is reasonably smooth in appearance (Tiscareno et al. 2005, DPS), with occultations indicating residuals less than 1 km upon a possibly non-zero eccentricity (R.G. French, personal communication, 2014). The other four (the inner and outer edges of the Encke Gap, the inner edge of the Keeler Gap, and the outer edge of the A ring itself) are characterized by wavy structure at moderate to high spatial frequencies, with amplitudes ranging from 2 to 30 km (Tiscareno et al. 2005, DPS).We will present a catalogue of wisp detections in Cassini images. We carry out repeated gaussian fits of the radial edge location in order to characterize edge structure and visually scan those fitted edges in order to detect wisps. With extensive coverage in longitude and in time, we will report on how wisps evolve and move, both within an orbit period and on longer timescales. We will also report on the frequency and interpretation of wisps that deviate from the standard morphology. We will discuss the implications of our results for the origin and nature of wisps, and for the larger picture of how masses interact within Saturn's rings.

  14. Liver support strategies: cutting-edge technologies.

    Science.gov (United States)

    Struecker, Benjamin; Raschzok, Nathanael; Sauer, Igor M

    2014-03-01

    The treatment of end-stage liver disease and acute liver failure remains a clinically relevant issue. Although orthotopic liver transplantation is a well-established procedure, whole-organ transplantation is invasive and increasingly limited by the unavailability of suitable donor organs. Artificial and bioartificial liver support systems have been developed to provide an alternative to whole organ transplantation, but despite three decades of scientific efforts, the results are still not convincing with respect to clinical outcome. In this Review, conceptual limitations of clinically available liver support therapy systems are discussed. Furthermore, alternative concepts, such as hepatocyte transplantation, and cutting-edge developments in the field of liver support strategies, including the repopulation of decellularized organs and the biofabrication of entirely new organs by printing techniques or induced organogenesis are analysed with respect to clinical relevance. Whereas hepatocyte transplantation shows promising clinical results, at least for the temporary treatment of inborn metabolic diseases, so far data regarding implantation of engineered hepatic tissue have only emerged from preclinical experiments. However, the evolving techniques presented here raise hope for bioengineered liver support therapies in the future.

  15. Edge enhancement of computed tomograms by digital unsharp masking.

    Science.gov (United States)

    Winter, J

    1980-04-01

    Edge enhanced images can be produced on existing commercial computed tomographic equipment by a method called "digital unsharp masking" without any expense or computer software development. This technique permits display of anatomic areas having an extremely wide range of densities, while making edge detail more apparent.

  16. Quantization of edge currents for continuous magnetic operators

    CERN Document Server

    Kellendonk, J

    2003-01-01

    For a magnetic Hamiltonian on a half-plane given as the sum of the Landau operator with Dirichlet boundary conditions and a random potential, a quantization theorem for the edge currents is proven. This shows that the concept of edge channels also makes sense in presence of disorder. Moreover, gaussian bounds on the heat kernel and its covariant derivatives are obtained.

  17. Shadow edge detection using geometric and photometric features

    NARCIS (Netherlands)

    Gijsenij, A.; Gevers, T.

    2009-01-01

    The detection of shadow and shading edges is a first step towards reducing the imaging effects that are caused by interactions of the light source with surfaces that are in the scene. As most of the algorithms for shadow edge detection use photometric information, geometric information have been

  18. Detecting the Edge of the Tongue: A Tutorial

    Science.gov (United States)

    Iskarous, Khalil

    2005-01-01

    The goal of this paper is to provide a tutorial introduction to the topic of edge detection of the tongue from ultrasound scans for researchers in speech science and phonetics. The method introduced here is Active Contours (also called snakes), a method for searching for an edge, assuming that it is a smooth curve in the image data. The advantage…

  19. Improvement of TNO type trailing edge noise models

    DEFF Research Database (Denmark)

    Fischer, Andreas; Bertagnolio, Franck; Aagaard Madsen, Helge

    2017-01-01

    The paper describes an improvement of the so-called TNO model to predict the noise emission from aerofoil sections due to the interaction of the boundary layer turbulence with the trailing edge. The surface pressure field close to the trailing edge acts as source of sound in the TNO model...

  20. Improvement of TNO type trailing edge noise models

    DEFF Research Database (Denmark)

    Fischer, Andreas; Bertagnolio, Franck; Aagaard Madsen, Helge

    2016-01-01

    The paper describes an improvement of the so-called TNO model to predict the noise emission from aerofoil sections due to the interaction of the boundary layer turbulence with the trailing edge. The surface pressure field close to the trailing edge acts as source of sound in the TNO model...

  1. Electron transport in edge-disordered graphene nanoribbons

    DEFF Research Database (Denmark)

    Saloriutta, Karri; Hancock, Y.; Karkkainen, Asta

    2011-01-01

    Ab initio methods are used to study the spin-resolved transport properties of graphene nanoribbons (GNRs) that have both chemical and structural edge disorder. Oxygen edge adsorbates on ideal and protruded ribbons are chosen as representative examples, with the protrusions forming the smallest...

  2. South African Identities on the Edge: Lauren Beukes's Moxyland ...

    African Journals Online (AJOL)

    This article explores the representation of identity in Lauren Beukes's dystopian novel, Moxyland (2008). We follow the work of various critics and argue that the text presents identity as fractured, riven and characterized by sharp edges. The edges in question refer to the boundaries of personal, corporeal, national and ...

  3. Observation of floating potential asymmetry in the edge plasma of ...

    Indian Academy of Sciences (India)

    Abstract. Edge plasma properties in a tokamak is an interesting subject of study from the view point of confinement and stability of tokamak plasma. The edge plasma of SINP-tokamak has been investigated using specially designed Langmuir probes. We have observed a poloidal asymmetry of floating potentials, particularly ...

  4. Edge Cover Domination in Mangoldt Graph | Madhavi | Momona ...

    African Journals Online (AJOL)

    In their recent study of arithmetic graphs associated with certain arithmetic functions, the authors have introduced a new class of arithmetic graphs associated with Mangoldt function Λ(n), n ≥ 1, an integer and studied their basic properties and vertex cover. In this paper the edge cover, edge domination set, bondage ...

  5. High-Resolution Stamp Fabrication by Edge Lithography

    NARCIS (Netherlands)

    Zhao, Yiping

    2010-01-01

    The aim of the project was to create high resolution stamps for thermal nanoimprint applications. The creation of nanoridges with sub-100 nm resolutions was explored by means of edge lithography via top-down routes, i.e. in combination with micromachining technology. Edge lithography is an add-on

  6. Processing of Superconductor-Normal-Superconductor Josephson Edge Junctions

    Science.gov (United States)

    Kleinsasser, A. W.; Barner, J. B.

    1997-01-01

    The electrical behavior of epitaxial superconductor-normal-superconductor (SNS) Josephson edge junctions is strongly affected by processing conditions. Ex-situ processes, utilizing photoresist and polyimide/photoresist mask layers, are employed for ion milling edges for junctions with Yttrium-Barium-Copper-Oxide (YBCO) electrodes and primarily Co-doped YBCO interlayers.

  7. Sliding mean edge estimation. [in digital image processing

    Science.gov (United States)

    Ford, G. E.

    1978-01-01

    A method for determining the locations of the major edges of objects in digital images is presented. The method is based on an algorithm utilizing maximum likelihood concepts. An image line-scan interval is processed to determine if an edge exists within the interval and its location. The proposed algorithm has demonstrated good results even in noisy images.

  8. Spiraling Edge: Fast Surface Reconstruction from Partially Organized Sample Points

    Energy Technology Data Exchange (ETDEWEB)

    Angel, E.; Crossno, P.

    1999-01-06

    Many applications produce three-dimensional points that must be further processed to generate a surface. Surface reconstruction algorithms that start with a set of unorganized points are extremely time-consuming. Often, however, points are generated such that there is additional information available to the reconstruction algorithm. We present a specialized algorithm for surface reconstruction that is three orders of magnitude faster than algorithms for the general case. In addition to sample point locations, our algorithm starts with normal information and knowledge of each point's neighbors. Our algorithm produces a localized approximation to the surface by creating a star-shaped triangulation between a point and a subset of its nearest neighbors. This surface patch is extended by locally triangulating each of the points along the edge of the patch. As each edge point is triangulated, it is removed from the edge and new edge points along the patch's edge are inserted in its place. The updated edge spirals out over the surface until the edge encounters a surface boundary and stops growing in that direction, or until the edge reduces to a small hole that fills itself in.

  9. Chinese Postman Problem on edge-colored multigraphs

    DEFF Research Database (Denmark)

    Gutin, Gregory; Jones, Mark; Sheng, Bin

    2017-01-01

    It is well-known that the Chinese Postman Problem on undirected and directed graphs is polynomial-time solvable. We extend this result to edge-colored multigraphs. Our result is in sharp contrast to the Chinese Postman Problem on mixed graphs, i.e., graphs with directed and undirected edges......, for which the problem is NP-hard....

  10. ON THE EDGE-BALANCED INDEX SETS OF PRODUCT GRAPHS

    Directory of Open Access Journals (Sweden)

    Elliot Krop

    2012-03-01

    Full Text Available We characterize strongly edge regular product graphs and find the edge-balanced index sets of complete bipartite graphs without a perfect matching, the direct product Kn X K2. We also prove a lemma that is helpful to determine theedge-balanced index sets of regular graphs.

  11. Subcomponent testing of trailing edge panels in wind turbine blades

    DEFF Research Database (Denmark)

    Branner, Kim; Berring, Peter; Haselbach, Philipp Ulrich

    2016-01-01

    This paper proposes a static subcomponent test method designed to check the compressive strength of the trailing edge region in wind turbine blades under a simplified loading. The paper presents numerical simulations using the proposed subcomponent test method and discusses its ability to be used...... for checking the compressive strength of the trailing edge region in wind turbine blades....

  12. Polarimetric Edge Detector Based on the Complex Wishart Distribution

    DEFF Research Database (Denmark)

    Skriver, Henning; Schou, Jesper; Nielsen, Allan Aasbjerg

    2001-01-01

    A new edge detector for polarimetric SAR data has been developed. The edge detector is based on a newly developed test statistic for equality of two complex covariance matrices following the complex Wishart distribution and an associated asymptotic probability for the test statistic. The new...... for the full polarimetric detector compared to single channel approaches....

  13. The mechanism of droplet formation in microfluidic EDGE systems

    NARCIS (Netherlands)

    Dijke, van K.C.; Ruiter, de R.; Schroën, C.G.P.H.; Boom, R.M.

    2010-01-01

    Edge-based droplet generation (EDGE) emulsification, which produces multiple, monodispersed droplets simultaneously at one droplet forming unit (introduced recently by our group), is studied in more detail with high-speed imaging, computational fluid dynamics and geometric modeling as research

  14. Precision truing of diamond wheel with sharp edge

    Science.gov (United States)

    Ge, Cheng; Guo, Bing; Zhao, QIngliang; Chen, Bing; Wang, Jinhu

    2014-08-01

    Diamond wheel with sharp edge has small contour structures, which can lead to fast wear of wheel in the grinding process. Traditional truing methods are hard to apply to this kind of wheels. Therefore, as for the difficulty of precision truing of diamond wheel with sharp edge, the novel methods for resin and metal bonded diamond wheels with sharp edge are presented, respectively. In this experiment, a conditioning procedure with rare metal alloy block Ta was used to true the resin bonded diamond grinding wheel and in the same way Nb alloy block was utilized to complete rough truing of metal bonded diamond grinding wheel. Then a CNC truing technique with rotational green carbide (GC) truing stick was applied to precise truing of metal bonded diamond grinding wheel. Methods mentioned above were measured in order to evaluate the performance of truing. Geometric features of the wheel sharp edge were duplicated on the organic glass (PMMA) in order to measure and calculate the radius of the sharp edge. The edge radius of trued resin bonded wheel and metal bonded wheel is perceived as an important assessment. The experiments results revealed that the edge radius of 12.45μm for the resin bonded wheel and the edge radius of 30.17μm for the metal bonded wheel could be achieved.

  15. First Order Statistics of Speckle around a Scatterer Volume Density Edge and Edge Detection in Ultrasound Images.

    Science.gov (United States)

    Li, Yue

    1990-01-01

    Ultrasonic imaging plays an important role in medical imaging. But the images exhibit a granular structure, commonly known as speckle. The speckle tends to mask the presence of low-contrast lesions and reduces the ability of a human observer to resolve fine details. Our interest in this research is to examine the problem of edge detection and come up with methods for improving the visualization of organ boundaries and tissue inhomogeneity edges. An edge in an image can be formed either by acoustic impedance change or by scatterer volume density change (or both). The echo produced from these two kinds of edges has different properties. In this work, it has been proved that the echo from a scatterer volume density edge is the Hilbert transform of the echo from a rough impedance boundary (except for a constant) under certain conditions. This result can be used for choosing the correct signal to transmit to optimize the performance of edge detectors and characterizing an edge. The signal to noise ratio of the echo produced by a scatterer volume density edge is also obtained. It is found that: (1) By transmitting a signal with high bandwidth ratio and low center frequency, one can obtain a higher signal to noise ratio. (2) For large area edges, the farther the transducer is from the edge, the larger is the signal to noise ratio. But for small area edges, the nearer the transducer is to the edge, the larger is the signal to noise ratio. These results enable us to maximize the signal to noise ratio by adjusting these parameters. (3) The signal to noise ratio is not only related to the ratio of scatterer volume densities at the edge, but also related to the absolute value of scatterer volume densities. Some of these results have been proved through simulation and experiment. Different edge detection methods have been used to detect simulated scatterer volume density edges to compare their performance. A so-called interlaced array method has been developed for speckle

  16. Optimizing 3D Triangulations to Recapture Sharp Edges

    DEFF Research Database (Denmark)

    Bærentzen, Jakob Andreas

    2006-01-01

    sharp edges. The energy is minimized using edge swapping, and this can be done either in a greedy fashion or using simulated annealing. The latter is more costly, but effectively avoids local minima. The method has been used on a number of models. Particularly good results have been obtained on digital......In this report, a technique for optimizing 3D triangulations is proposed. The method seeks to minimize an energy defined as a sum of energy terms for each edge in a triangle mesh. The main contribution is a novel per edge energy which strikes a balance between penalizing dihedral angle yet allowing...... terrain models. It is demonstrated how the method has been able to recapture sharp edges which are clearly present in the data but not reflected by the original triangulation of the elevation points....

  17. Living on the edge: a review of the literature.

    Science.gov (United States)

    PetersonLund, Robin R

    2013-10-01

    A comprehensive review of the literature of the universal experience of living on the edge is discussed. Literature was reviewed from biology, criminology, ecology, economics, ethics, finance, fine arts, historical biography, medicine, nursing, philosophy, physiology, psychology, sociology, and theology. Three themes emerged with this literature review: living on the edge as a sacred place one travels to or where one lives, living on the edge as a choice in taking risks and surviving danger, and living on the edge as engaging with health experiences in which persons and nurses coparticipate. Living on the edge is a visionary quest into a new frontier that holds illimitable possibilities that transform the world. The literature is discussed according to theoretical and research findings.

  18. Evolutionary Approach Based on Active Edges Detection for Images Segmentation

    Directory of Open Access Journals (Sweden)

    Slatnia Sihem

    2015-03-01

    Full Text Available There are many methods for segmentation which vary strongly in their approach to the problem of image segmentation. In this paper, We specified the study in a particular segmentation method of radiological images based on the active edges detection. The optimize solutions was chosen as the genetic algorithm optimization method, and to compare this formalism with other existing methods, we chose a greedy algorithm is criterion for its timeliness. we propose a method of genetic active edge detection in images gray level. In fact, for the convergence of the edge to the object edges, we use the classic and the greedy method. Indeed, the proposed method is based on the active edges optimization using the genetic algorithms process to minimize a sum various energies, in order to evolve a population of snakes to an individual who has the minimum energy.

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

    Science.gov (United States)

    Leonov, A O; Mostovoy, M

    2017-02-27

    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.

  20. Fuzzy Index to Evaluate Edge Detection in Digital Images

    Science.gov (United States)

    Perez-Ornelas, Felicitas; Mendoza, Olivia; Melin, Patricia; Castro, Juan R.; Rodriguez-Diaz, Antonio; Castillo, Oscar

    2015-01-01

    In literature, we can find different metrics to evaluate the detected edges in digital images, like Pratt's figure of merit (FOM), Jaccard’s index (JI) and Dice’s coefficient (DC). These metrics compare two images, the first one is the reference edges image, and the second one is the detected edges image. It is important to mention that all existing metrics must binarize images before their evaluation. Binarization step causes information to be lost because an incomplete image is being evaluated. In this paper, we propose a fuzzy index (FI) for edge evaluation that does not use a binarization step. In order to process all detected edges, images are represented in their fuzzy form and all calculations are made with fuzzy sets operators and fuzzy Euclidean distance between both images. Our proposed index is compared to the most used metrics using synthetic images, with good results. PMID:26115362

  1. Strain-activated edge reconstruction of graphene nanoribbons

    KAUST Repository

    Cheng, Yingchun

    2012-02-17

    The edge structure and width of graphene nanoribbons (GNRs) are crucial factors for the electronic properties. A combination of experiment and first-principles calculations allows us to determine the mechanism of the hexagon-hexagon to pentagon-heptagon transformation. GNRs thinner than 2 nm have been fabricated by bombardment of graphene with high-energetic Au clusters. The edges of the GNRs are modified in situ by electron irradiation. Tensile strain along the edge decreases the transformation energy barrier. Antiferromagnetism and a direct band gap are found for a zigzag GNR, while a fully reconstructed GNR shows an indirect band gap. A GNR reconstructed on only one edge exhibits ferromagnetism. We propose that strain is an effective method to tune the edge and, therefore, the electronic structure of thin GNRs for graphene-based electronics.

  2. ESIM: Edge Similarity for Screen Content Image Quality Assessment.

    Science.gov (United States)

    Ni, Zhangkai; Ma, Lin; Zeng, Huanqiang; Chen, Jing; Cai, Canhui; Ma, Kai-Kuang

    2017-10-01

    In this paper, an accurate full-reference image quality assessment (IQA) model developed for assessing screen content images (SCIs), called the edge similarity (ESIM), is proposed. It is inspired by the fact that the human visual system (HVS) is highly sensitive to edges that are often encountered in SCIs; therefore, essential edge features are extracted and exploited for conducting IQA for the SCIs. The key novelty of the proposed ESIM lies in the extraction and use of three salient edge features-i.e., edge contrast, edge width, and edge direction. The first two attributes are simultaneously generated from the input SCI based on a parametric edge model, while the last one is derived directly from the input SCI. The extraction of these three features will be performed for the reference SCI and the distorted SCI, individually. The degree of similarity measured for each above-mentioned edge attribute is then computed independently, followed by combining them together using our proposed edge-width pooling strategy to generate the final ESIM score. To conduct the performance evaluation of our proposed ESIM model, a new and the largest SCI database (denoted as SCID) is established in our work and made to the public for download. Our database contains 1800 distorted SCIs that are generated from 40 reference SCIs. For each SCI, nine distortion types are investigated, and five degradation levels are produced for each distortion type. Extensive simulation results have clearly shown that the proposed ESIM model is more consistent with the perception of the HVS on the evaluation of distorted SCIs than the multiple state-of-the-art IQA methods.

  3. Edge-to-edge percutaneous repair of severe mitral regurgitation--state-of-the-art for Mitraclip® implantation

    DEFF Research Database (Denmark)

    Alegria-Barrero, Eduardo; Chan, Pak Hei; Paulo, Manuel

    2012-01-01

    MitraClip® therapy is a percutaneous edge-to-edge plication of the mitral leaflets, mimicking the Alfieri surgical technique. MitraClip® implantation is a safe procedure, and survival outcomes in high-surgical-risk patients are superior to historical controls. Despite these results, questions...

  4. Morphological rates of angiosperm seed size evolution.

    Science.gov (United States)

    Sims, Hallie J

    2013-05-01

    The evolution of seed size among angiosperms reflects their ecological diversification in a complex fitness landscape of life-history strategies. The lineages that have evolved seeds beyond the upper and lower boundaries that defined nonflowering seed plants since the Paleozoic are more dispersed across the angiosperm phylogeny than would be expected under a neutral model of phenotypic evolution. Morphological rates of seed size evolution estimated for 40 clades based on 17,375 species ranged from 0.001 (Garryales) to 0.207 (Malvales). Comparative phylogenetic analysis indicated that morphological rates are not associated with the clade's seed size but are negatively correlated with the clade's position in the overall distribution of angiosperm seed sizes; clades with seed sizes closer to the angiosperm mean had significantly higher morphological rates than clades with extremely small or extremely large seeds. Likewise, per-clade taxonomic diversification rates are not associated with the seed size of the clade but with where the clade falls within the angiosperm seed size distribution. These results suggest that evolutionary rates (morphological and taxonomic) are elevated in densely occupied regions of the seed morphospace relative to lineages whose ecophenotypic innovations have moved them toward the edges. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  5. Evolution of Linux operating system network

    Science.gov (United States)

    Xiao, Guanping; Zheng, Zheng; Wang, Haoqin

    2017-01-01

    Linux operating system (LOS) is a sophisticated man-made system and one of the most ubiquitous operating systems. However, there is little research on the structure and functionality evolution of LOS from the prospective of networks. In this paper, we investigate the evolution of the LOS network. 62 major releases of LOS ranging from versions 1.0 to 4.1 are modeled as directed networks in which functions are denoted by nodes and function calls are denoted by edges. It is found that the size of the LOS network grows almost linearly, while clustering coefficient monotonically decays. The degree distributions are almost the same: the out-degree follows an exponential distribution while both in-degree and undirected degree follow power-law distributions. We further explore the functionality evolution of the LOS network. It is observed that the evolution of functional modules is shown as a sequence of seven events (changes) succeeding each other, including continuing, growth, contraction, birth, splitting, death and merging events. By means of a statistical analysis of these events in the top 4 largest components (i.e., arch, drivers, fs and net), it is shown that continuing, growth and contraction events occupy more than 95% events. Our work exemplifies a better understanding and describing of the dynamics of LOS evolution.

  6. Turbine Airfoil Leading Edge Film Cooling Bibliography: 1972–1998

    Directory of Open Access Journals (Sweden)

    D. M. Kercher

    2000-01-01

    Full Text Available Film cooling for turbine airfoil leading edges has been a common practice for at least 35 years as turbine inlet gas temperatures and pressures have continually increased along with cooling air temperatures for higher engine cycle efficiency. With substantial engine cycle performance improvements from higher gas temperatures, it has become increasingly necessary to film cool nozzle and rotor blade leading edges since external heat transfer coefficients and thus heat load are the highest in this airfoil region. Optimum cooling air requirements in this harsh environment has prompted a significant number of film cooling investigations and analytical studies reported over the past 25 years from academia, industry and government agencies. Substantial progress has been made in understanding the complex nature of leading edge film cooling from airfoil cascades, simulated airfoil leading edges and environment. This bibliography is a report of the open-literature references available which provide information on the complex aero–thermo interaction of leading edge gaseous film cooling with mainstream flow. From much of this investigative information has come successful operational leading edge film cooling design systems capable of sustaining airfoil leading edge durability in very hostile turbine environments.

  7. Edge-Based Defocus Blur Estimation With Adaptive Scale Selection.

    Science.gov (United States)

    Karaali, Ali; Jung, Claudio Rosito

    2018-03-01

    Objects that do not lie at the focal distance of a digital camera generate defocused regions in the captured image. This paper presents a new edge-based method for spatially varying defocus blur estimation using a single image based on reblurred gradient magnitudes. The proposed approach initially computes a scale-consistent edge map of the input image and selects a local reblurring scale aiming to cope with noise, edge mis-localization, and interfering edges. An initial blur estimate is computed at the detected scale-consistent edge points and a novel connected edge filter is proposed to smooth the sparse blur map based on pixel connectivity within detected edge contours. Finally, a fast guided filter is used to propagate the sparse blur map through the whole image. Experimental results show that the proposed approach presents a very good compromise between estimation error and running time when compared with the state-of-the-art methods. We also explore our blur estimation method in the context of image deblurring, and show that metrics typically used to evaluate blur estimation may not correlate as expected with the visual quality of the deblurred image.

  8. Tablet compression tooling - Impact of punch face edge modification.

    Science.gov (United States)

    Anbalagan, Parthiban; Heng, Paul Wan Sia; Liew, Celine Valeria

    2017-05-30

    The influence of punch face edge geometry modification on tablet compression and the properties of the resultant tablets produced on a rotary press were investigated. The results revealed that tablets produced from the punches with radius edge face geometry consistently displayed better physical quality; higher tensile strength and lower capping tendency. Modification of the angled edge of the bevel face to the curved edge of the radius face, enabled deeper punch penetration in the die cavity during the compression cycle, bringing about greater compact densification. Improved die fill packing increased interparticulate bond formation and helped to dissipate destructive elasticity within the compact, consequently reduced tablet expansion during the decompression phase. The positive impact of punch face edge modification was also more noticeable at a higher turret speed. The application of the precompression force along with dwell time extension amplified the tableting performance of radius edge punch face design to a greater extent when compared to bevel edge punch face design. This could be attributed to the enhanced packing efficiency at both precompression and main compression stages. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Edge-oriented dual-dictionary guided enrichment (EDGE) for MRI-CT image reconstruction.

    Science.gov (United States)

    Li, Liang; Wang, Bigong; Wang, Ge

    2016-01-01

    In this paper, we formulate the joint/simultaneous X-ray CT and MRI image reconstruction. In particular, a novel algorithm is proposed for MRI image reconstruction from highly under-sampled MRI data and CT images. It consists of two steps. First, a training dataset is generated from a series of well-registered MRI and CT images on the same patients. Then, an initial MRI image of a patient can be reconstructed via edge-oriented dual-dictionary guided enrichment (EDGE) based on the training dataset and a CT image of the patient. Second, an MRI image is reconstructed using the dictionary learning (DL) algorithm from highly under-sampled k-space data and the initial MRI image. Our algorithm can establish a one-to-one correspondence between the two imaging modalities, and obtain a good initial MRI estimation. Both noise-free and noisy simulation studies were performed to evaluate and validate the proposed algorithm. The results with different under-sampling factors show that the proposed algorithm performed significantly better than those reconstructed using the DL algorithm from MRI data alone.

  10. Mechanics of mitral valve edge-to-edge-repair and MitraClip procedure.

    Science.gov (United States)

    Bhattacharya, Shamik; He, Zhaoming

    2015-01-01

    The edge-to-edge repair (ETER) technique has been used as a stand-alone procedure, or as a secondary procedure with ring annuloplasty for degenerative, functional mitral regurgitation, or for mitral regurgitation of other kinds of valvular etiologies. The percutaneous MitraClip technique based on ETER has been used in patients who are inoperable or at high surgical risk. However, adverse events such as residual mitral regurgitation, and clip detachment or fracture indicate that the mechanics underlying these procedures is not well understood. Therefore, current studies on mitral valve functionality and mechanics related to the ETER and MitraClip procedures are reviewed to improve the efficacy and safety of both procedures. Extensive in vivo, in vitro, and in silico studies related to ETER and MitraClip procedures along with MitraClip clinical trial results are presented and discussed herein. The ETER suture force and the mitral valve tissue mechanics and hemodynamics of each procedure are discussed. A quantitative understanding of the interplay of mitral valve components and as to biological response to the procedures remains challenging. Based on mitral valve mechanics, ETER or MitraClip therapy can be optimized to enhance repair efficacy and durability.

  11. Aerodynamic Analysis of Trailing Edge Enlarged Wind Turbine Airfoils

    Science.gov (United States)

    Xu, Haoran; Shen, Wenzhong; Zhu, Weijun; Yang, Hua; Liu, Chao

    2014-06-01

    The aerodynamic performance of blunt trailing edge airfoils generated from the DU- 91-W2-250, DU-97-W-300 and DU-96-W-350 airfoils by enlarging the thickness of trailing edge symmetrically from the location of maximum thickness to chord to the trailing edge were analyzed by using CFD and RFOIL methods at a chord Reynolds number of 3 × 106. The goal of this study is to analyze the aerodynamic performance of blunt trailing edge airfoils with different thicknesses of trailing edge and maximum thicknesses to chord. The steady results calculated by the fully turbulent k-ω SST, transitional k-ω SST model and RFOIL all show that with the increase of thickness of trailing edge, the linear region of lift is extended and the maximum lift also increases, the increase rate and amount of lift become limited gradually at low angles of attack, while the drag increases dramatically. For thicker airfoils with larger maximum thickness to chord length, the increment of lift is larger than that of relatively thinner airfoils when the thickness of blunt trailing edge is increased from 5% to 10% chord length. But too large lift can cause abrupt stall which is profitless for power output. The transient characteristics of blunt trailing edge airfoils are caused by blunt body vortices at low angles of attack, and by the combined effect of separation and blunt body vortices at large angles of attack. With the increase of thickness of blunt trailing edge, the vibration amplitudes of lift and drag curves increase. The transient calculations over-predict the lift at large angles of attack and drag at all angles of attack than the steady calculations which is likely to be caused by the artificial restriction of the flow in two dimensions.

  12. Structural Health Monitoring Analysis for the Orbiter Wing Leading Edge

    Science.gov (United States)

    Yap, Keng C.

    2010-01-01

    This viewgraph presentation reviews Structural Health Monitoring Analysis for the Orbiter Wing Leading Edge. The Wing Leading Edge Impact Detection System (WLE IDS) and the Impact Analysis Process are also described to monitor WLE debris threats. The contents include: 1) Risk Management via SHM; 2) Hardware Overview; 3) Instrumentation; 4) Sensor Configuration; 5) Debris Hazard Monitoring; 6) Ascent Response Summary; 7) Response Signal; 8) Distribution of Flight Indications; 9) Probabilistic Risk Analysis (PRA); 10) Model Correlation; 11) Impact Tests; 12) Wing Leading Edge Modeling; 13) Ascent Debris PRA Results; and 14) MM/OD PRA Results.

  13. Colossal spin transfer torque effect on skyrmion along the edge.

    Science.gov (United States)

    Iwasaki, Junichi; Koshibae, Wataru; Nagaosa, Naoto

    2014-08-13

    We study by the micromagnetic simulations the skyrmion motion along the edge driven by the current transverse to it. We found that (i) the velocity is enhanced by the factor of ∼ 1/α (α: the Gilbert damping) with the maximum value determined only by the confining force from the edge, (ii) the inertia appear due to the confining potential with the coordinate perpendicular to the edge playing the role of the kinetic momentum, and (iii) the collision between the two skyrmions is almost elastic without causing any internal distortions.

  14. On Super Edge-Antimagic Total Labeling Of Subdivided Stars

    Directory of Open Access Journals (Sweden)

    Javaid Muhammad

    2014-11-01

    Full Text Available In 1980, Enomoto et al. proposed the conjecture that every tree is a super (a, 0-edge-antimagic total graph. In this paper, we give a partial sup- port for the correctness of this conjecture by formulating some super (a, d- edge-antimagic total labelings on a subclass of subdivided stars denoted by T(n, n + 1, 2n + 1, 4n + 2, n5, n6, . . . , nr for different values of the edge- antimagic labeling parameter d, where n ≥ 3 is odd, nm = 2m−4(4n+1+1, r ≥ 5 and 5 ≤ m ≤ r.

  15. Bryophyte responses to microclimatic edge effects across riparian buffers.

    Science.gov (United States)

    Stewart, Katherine J; Mallik, Azim U

    2006-08-01

    Although riparian buffers are an important aspect of forest management in the boreal forest of Canada, little is known about the habitat conditions within buffers, due in part to complex edge effects in response to both the upland clearcut and the stream. We investigated microclimatic conditions and bryophyte growth and vitality in seven locations between the stream edge and 60 m into the upland undisturbed conifer forests and at the clearcut sites with riparian buffer 30 km northwest of Thunder Bay, Ontario, Canada. We hypothesized that the growth and vitality of a pleurocarpous moss, Hylocomium splendens, and an acrocarpous moss, Polytrichum commune, would be directly related to the microclimatic gradients detected. We further hypothesized that sensitivity of the bryophytes to environmental factors will vary depending on their life form type, i.e., pleurocarpous moss will respond differently than the acrocarpous moss. Both bryophyte species were transplanted in pots and placed at 10-m intervals along 60-m transects perpendicular to the stream across the buffer and undisturbed sites. Bryophyte growth, cover, and vitality, as well as microclimatic parameters and plant cover, were measured over the summer in 2003. The riparian buffers were simultaneously affected by microclimatic gradients extending from both the clearcut edge and the riparian-upland ecotonal edge. Both bryophyte species responded to changes in the microclimatic conditions. However, vapor pressure deficit (VPD) was the most important factor influencing the growth of H. splendens, whereas for P. commune growth soil moisture was most important. Our study confirms earlier findings that interior forest bryophytes such as H. splendens can be used as indicators to monitor edge effects and biodiversity recovery following forest harvesting. We demonstrate that growth and vitality of these bryophytes reflect the prevailing near-ground microclimatic conditions at the forest edges. Abundance estimates of such

  16. Edge magnetism of finite graphene-like nanoribbons in the presence of intrinsic spin-orbit interaction and perpendicular electric field.

    Science.gov (United States)

    Krompiewski, S

    2016-08-05

    This paper elucidates the combined effect of intrinsic spin-orbit interaction (ISOI) and perpendicular electric field [Formula: see text] on edge states in finite graphene-like nanoribbons. It is shown that the ISOI generates magnetic anisotropy which makes the in-plane edge magnetization configuration more energetically stable than the commonly studied out-of-plane one. The anisotropy less severely suppresses the former configuration than the latter. As concerns the E z effect, the following evolution of electric transport properties is predicted: magnetic insulator, non-magnetic narrow-band semiconductor, and finally non-magnetic band insulator.

  17. Functional evolution of a morphogenetic gradient.

    Science.gov (United States)

    Kwan, Chun Wai; Gavin-Smyth, Jackie; Ferguson, Edwin L; Schmidt-Ott, Urs

    2016-12-22

    Bone Morphogenetic Proteins (BMPs) pattern the dorsal-ventral axis of bilaterian embryos; however, their roles in the evolution of body plan are largely unknown. We examined their functional evolution in fly embryos. BMP signaling specifies two extraembryonic tissues, the serosa and amnion, in basal-branching flies such as Megaselia abdita, but only one, the amnioserosa, in Drosophila melanogaster. The BMP signaling dynamics are similar in both species until the beginning of gastrulation, when BMP signaling broadens and intensifies at the edge of the germ rudiment in Megaselia, while remaining static in Drosophila. Here we show that the differences in gradient dynamics and tissue specification result from evolutionary changes in the gene regulatory network that controls the activity of a positive feedback circuit on BMP signaling, involving the tumor necrosis factor alpha homolog eiger. These data illustrate an evolutionary mechanism by which spatiotemporal changes in morphogen gradients can guide tissue complexity.

  18. Edge-Based Image Compression with Homogeneous Diffusion

    Science.gov (United States)

    Mainberger, Markus; Weickert, Joachim

    It is well-known that edges contain semantically important image information. In this paper we present a lossy compression method for cartoon-like images that exploits information at image edges. These edges are extracted with the Marr-Hildreth operator followed by hysteresis thresholding. Their locations are stored in a lossless way using JBIG. Moreover, we encode the grey or colour values at both sides of each edge by applying quantisation, subsampling and PAQ coding. In the decoding step, information outside these encoded data is recovered by solving the Laplace equation, i.e. we inpaint with the steady state of a homogeneous diffusion process. Our experiments show that the suggested method outperforms the widely-used JPEG standard and can even beat the advanced JPEG2000 standard for cartoon-like images.

  19. Amount of Future Forest Edge at a 2 Hectare Scale

    Data.gov (United States)

    U.S. Environmental Protection Agency — Forests provide economic and ecological value. High amounts of forest edge indicates a highly fragmented forest, which generally diminishes those economic and...

  20. Amount of Forest Edge at a 65 Hectare Scale

    Data.gov (United States)

    U.S. Environmental Protection Agency — Forests provide economic and ecological value. High amounts of forest edge indicates a highly fragmented forest, which generally diminishes those economic and...

  1. Edge delamination in angle-ply composite laminates, part 5

    Science.gov (United States)

    Wang, S. S.

    1981-01-01

    A theoretical method was developed for describing the edge delamination stress intensity characteristics in angle-ply composite laminates. The method is based on the theory of anisotropic elasticity. The edge delamination problem is formulated using Lekhnitskii's complex-variable stress potentials and an especially developed eigenfunction expansion method. The method predicts exact orders of the three-dimensional stress singularity in a delamination crack tip region. With the aid of boundary collocation, the method predicts the complete stress and displacement fields in a finite-dimensional, delaminated composite. Fracture mechanics parameters such as the mixed-mode stress intensity factors and associated energy release rates for edge delamination can be calculated explicity. Solutions are obtained for edge delaminated (theta/-theta theta/-theta) angle-ply composites under uniform axial extension. Effects of delamination lengths, fiber orientations, lamination and geometric variables are studied.

  2. Potential environmental effects of the leading edge hydrokinetic energy technology.

    Science.gov (United States)

    2017-05-01

    The Volpe Center evaluated potential environmental challenges and benefits of the ARPA-E funded research project, Marine Hydrokinetic Energy Harvesting Using Cyber-Physical Systems, led by Brown University. The Leading Edge research team develo...

  3. Amount of Forest Edge at a 2 Hectare Scale

    Data.gov (United States)

    U.S. Environmental Protection Agency — Forests provide economic and ecological value. High amounts of forest edge indicates a highly fragmented forest, which generally diminishes those economic and...

  4. Waters Edge Land Company, LLC - Clean Water Act Public Notice

    Science.gov (United States)

    The EPA is providing notice of an Administrative Penalty Assessment in the form of an Expedited Storm Water Settlement Agreement against Waters Edge Land Company, LLC, a business located at 10800 Farley St. Overland Park, KS, for alleged violations located

  5. Transmission Bragg edge spectroscopy measurements at ORNL Spallation Neutron Source

    Science.gov (United States)

    Tremsin, A. S.; McPhate, J. B.; Vallerga, J. V.; Siegmund, O. H. W.; Feller, W. B.; Bilheux, H. Z.; Molaison, J. J.; Tulk, C. A.; Crow, L.; Cooper, R. G.; Penumadu, D.

    2010-11-01

    Results of neutron transmission Bragg edge spectroscopic experiments performed at the SNAP beamline of the Spallation Neutron Source are presented. A high resolution neutron counting detector with a neutron sensitive microchannel plate and Timepix ASIC readout is capable of energy resolved two dimensional mapping of neutron transmission with spatial accuracy of ~55 μm, limited by the readout pixel size, and energy resolution limited by the duration of the initial neutron pulse. A two dimensional map of the Fe 110 Bragg edge position was obtained for a bent steel screw sample. Although the neutron pulse duration corresponded to ~30 mÅ energy resolution for 15.3 m flight path, the accuracy of the Bragg edge position in our measurements was improved by analytical fitting to a few mÅ level. A two dimensional strain map was calculated from measured Bragg edge values with an accuracy of ~few hundreds μistrain for 300s of data acquisition time.

  6. Surface Micromachined Arrays of Transition-Edge Detectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An innovative surface micromachining technique is described for the fabrication of closely-packed arrays of transition edge sensor (TES) x-ray microcalorimeters....

  7. Intercultural Knowledge Flows in Edge Organizations: Trust as an Enabler

    National Research Council Canada - National Science Library

    Gavrieli, Dana A; Scott, W. R

    2005-01-01

    ...., across military services and coalition partners) and knowledge flows. A major factor that emerges as an enabler of knowledge flows, especially in dynamic environments such as those in which Edge organizations operate, is trust...

  8. The Performance of Edge Organizations in a Collaborative Task

    National Research Council Canada - National Science Library

    Chang, Kok M

    2005-01-01

    .... In this thesis, the author investigates how the various characteristics of agents influence the efficiency of an edge organization in an intelligence-gathering task using an agent-based simulation...

  9. Analyzing edge detection techniques for feature extraction in dental radiographs

    Directory of Open Access Journals (Sweden)

    Kanika Lakhani

    2016-09-01

    Full Text Available Several dental problems can be detected using radiographs but the main issue with radiographs is that they are not very prominent. In this paper, two well known edge detection techniques have been implemented for a set of 20 radiographs and number of pixels in each image has been calculated. Further, Gaussian filter has been applied over the images to smoothen the images so as to highlight the defect in the tooth. If the images data are available in the form of pixels for both healthy and decayed tooth, the images can easily be compared using edge detection techniques and the diagnosis is much easier. Further, Laplacian edge detection technique is applied to sharpen the edges of the given image. The aim is to detect discontinuities in dental radiographs when compared to original healthy tooth. Future work includes the feature extraction on the images for the classification of dental problems.

  10. Shape Memory Alloys Application: Trailing Edge Shape Control

    National Research Council Canada - National Science Library

    Berton, Benoit

    2006-01-01

    .... A demonstrator of this adaptive trailing edge has been designed and manufactured. An original actuation concept has been developed based on a mixed system made of push-pull SMA (Shape Memory Alloy...

  11. Selective Formation of Zigzag Edges in Graphene Cracks.

    Science.gov (United States)

    Fujihara, Miho; Inoue, Ryosuke; Kurita, Rei; Taniuchi, Toshiyuki; Motoyui, Yoshihito; Shin, Shik; Komori, Fumio; Maniwa, Yutaka; Shinohara, Hisanori; Miyata, Yasumitsu

    2015-09-22

    We report the thermally induced unconventional cracking of graphene to generate zigzag edges. This crystallography-selective cracking was observed for as-grown graphene films immediately following the cooling process subsequent to chemical vapor deposition (CVD) on Cu foil. Results from Raman spectroscopy show that the crack-derived edges have smoother zigzag edges than the chemically formed grain edges of CVD graphene. Using these cracks as nanogaps, we were also able to demonstrate the carrier tuning of graphene through the electric field effect. Statistical analysis of visual observations indicated that the crack formation results from uniaxial tension imparted by the Cu substrates together with the stress concentration at notches in the polycrystalline graphene films. On the basis of simulation results using a simplified thermal shrinkage model, we propose that the cooling-induced tension is derived from the transient lattice expansion of narrow Cu grains imparted by the thermal shrinkage of adjacent Cu grains.

  12. A Computational Modeling Mystery Involving Airfoil Trailing Edge Treatments

    Science.gov (United States)

    Choo, Yeunun; Epps, Brenden

    2015-11-01

    In a curious result, Fairman (2002) observed that steady RANS calculations predicted larger lift than the experimentally-measured data for six different airfoils with non-traditional trailing edge treatments, whereas the time average of unsteady RANS calculations matched the experiments almost exactly. Are these results reproducible? If so, is the difference between steady and unsteady RANS calculations a numerical artifact, or is there a physical explanation? The goals of this project are to solve this thirteen year old mystery and further to model viscous/load coupling for airfoils with non-traditional trailing edges. These include cupped, beveled, and blunt trailing edges, which are common anti-singing treatments for marine propeller sections. In this talk, we present steady and unsteady RANS calculations (ANSYS Fluent) with careful attention paid to the possible effects of asymmetric unsteady vortex shedding and the modeling of turbulence anisotropy. The effects of non-traditional trailing edge treatments are visualized and explained.

  13. Improvement and implementation for Canny edge detection algorithm

    Science.gov (United States)

    Yang, Tao; Qiu, Yue-hong

    2015-07-01

    Edge detection is necessary for image segmentation and pattern recognition. In this paper, an improved Canny edge detection approach is proposed due to the defect of traditional algorithm. A modified bilateral filter with a compensation function based on pixel intensity similarity judgment was used to smooth image instead of Gaussian filter, which could preserve edge feature and remove noise effectively. In order to solve the problems of sensitivity to the noise in gradient calculating, the algorithm used 4 directions gradient templates. Finally, Otsu algorithm adaptively obtain the dual-threshold. All of the algorithm simulated with OpenCV 2.4.0 library in the environments of vs2010, and through the experimental analysis, the improved algorithm has been proved to detect edge details more effectively and with more adaptability.

  14. Variable range of the RKKY interaction in edged graphene

    DEFF Research Database (Denmark)

    Duffy, J M; Gorman, P D; Power, S R

    2014-01-01

    The indirect exchange interaction is one of the key factors in determining the overall alignment of magnetic impurities embedded in metallic host materials. In this work we examine the range of this interaction in magnetically doped graphene systems in the presence of armchair edges using...... a combination of analytical and numerical Green function approaches. We consider both a semi-infinite sheet of graphene with a single armchair edge, and also quasi-one-dimensional armchair-edged graphene nanoribbons (GNRs). While we find signals of the bulk decay rate in semi-infinite graphene and signals...... of the expected one-dimensional decay rate in GNRs, we also find an unusually rapid decay for certain instances in both, which manifests itself whenever the impurities are located at sites which are a multiple of three atoms from the edge. This decay behavior emerges from both the analytic and numerical...

  15. The effect of the band edges on the Seebeck coefficient.

    Science.gov (United States)

    Sonntag, Joachim

    2010-06-16

    The classical thermopower formulae generally applied for the calculation of the Seebeck coefficient S are argued to be incomplete. S can be separated into two different contributions, a scattering term, S(0), and a thermodynamic term, ΔS, representing the additional change of the electrochemical potential μ with temperature T caused by 'non-scattering' effects, for instance, the band edge shift with T. On the basis of this separation into S(0) and ΔS, it is shown that shifts of the band edges with T lead to an additional contribution to the classical thermopower formulae. This separation provides the basis for an interpretation of positive thermopowers measured for many metals. Positive thermopower is expected if the energy of the conduction band edge increases with T and if this effect overcompensates for the influence of the energy dependent conductivity, σ(E). Using experimental thermopower data, the band edge shifts are determined for a series of liquid normal metals.

  16. 29 CFR 1917.112 - Guarding of edges.

    Science.gov (United States)

    2010-07-01

    ... (CONTINUED) MARINE TERMINALS Terminal Facilities § 1917.112 Guarding of edges. (a) Vehicle protection. (1... structures leading to pilings or vessel mooring or berthing installations, which present a hazard of falling...

  17. A distributed Canny edge detector: algorithm and FPGA implementation.

    Science.gov (United States)

    Xu, Qian; Varadarajan, Srenivas; Chakrabarti, Chaitali; Karam, Lina J

    2014-07-01

    The Canny edge detector is one of the most widely used edge detection algorithms due to its superior performance. Unfortunately, not only is it computationally more intensive as compared with other edge detection algorithms, but it also has a higher latency because it is based on frame-level statistics. In this paper, we propose a mechanism to implement the Canny algorithm at the block level without any loss in edge detection performance compared with the original frame-level Canny algorithm. Directly applying the original Canny algorithm at the block-level leads to excessive edges in smooth regions and to loss of significant edges in high-detailed regions since the original Canny computes the high and low thresholds based on the frame-level statistics. To solve this problem, we present a distributed Canny edge detection algorithm that adaptively computes the edge detection thresholds based on the block type and the local distribution of the gradients in the image block. In addition, the new algorithm uses a nonuniform gradient magnitude histogram to compute block-based hysteresis thresholds. The resulting block-based algorithm has a significantly reduced latency and can be easily integrated with other block-based image codecs. It is capable of supporting fast edge detection of images and videos with high resolutions, including full-HD since the latency is now a function of the block size instead of the frame size. In addition, quantitative conformance evaluations and subjective tests show that the edge detection performance of the proposed algorithm is better than the original frame-based algorithm, especially when noise is present in the images. Finally, this algorithm is implemented using a 32 computing engine architecture and is synthesized on the Xilinx Virtex-5 FPGA. The synthesized architecture takes only 0.721 ms (including the SRAM READ/WRITE time and the computation time) to detect edges of 512 × 512 images in the USC SIPI database when clocked at 100

  18. Dynamic Stall Characteristics of Drooped Leading Edge Airfoils

    Science.gov (United States)

    Sankar, Lakshmi N.; Sahin, Mehmet; Gopal, Naveen

    2000-01-01

    Helicopters in high-speed forward flight usually experience large regions of dynamic stall over the retreating side of the rotor disk. The rapid variations in the lift and pitching moments associated with the stall process can result in vibratory loads, and can cause fatigue and failure of pitch links. In some instances, the large time lag between the aerodynamic forces and the blade motion can trigger stall flutter. A number of techniques for the alleviation of dynamic stall have been proposed and studied by researchers. Passive and active control techniques have both been explored. Passive techniques include the use of high solidity rotors that reduce the lift coefficients of individual blades, leading edge slots and leading edge slats. Active control techniques include steady and unsteady blowing, and dynamically deformable leading edge (DDLE) airfoils. Considerable amount of experimental and numerical data has been collected on the effectiveness of these concepts. One concept that has not received as much attention is the drooped-leading edge airfoil idea. It has been observed in wind tunnel studies and flight tests that drooped leading edge airfoils can have a milder dynamic stall, with a significantly milder load hysteresis. Drooped leading edge airfoils may not, however, be suitable at other conditions, e.g. in hover, or in transonic flow. Work needs to be done on the analysis and design of drooped leading edge airfoils for efficient operation in a variety of flight regimes (hover, dynamic stall, and transonic flow). One concept that is worthy of investigation is the dynamically drooping airfoil, where the leading edge shape is changed roughly once-per-rev to mitigate the dynamic stall.

  19. Aerothermodynamic Optimization of Aerospace Plane Airfoil Leading Edge

    OpenAIRE

    Zhou, Chen; Wang, Zhijin; Zhi, Jiaoyang; Kretov, Anatolii

    2017-01-01

    ABSTRACT: Aiming to mitigate the aerodynamic heating during hypersonic re-entry, the aerothermodynamic optimization of aerospace plane airfoil leading edge is conducted. Lift-to-drag ratio at landing condition is taken as a constraint to ensure the landing aerodynamic performance. First, airfoil profile is parametrically described to be more advantageous during the optimization process, and the Hicks-Henne type function is improved considering its application on the airfoil leading edge. Comp...

  20. Matrix model of QCD: Edge localized glueballs and phase transitions

    Science.gov (United States)

    Acharyya, Nirmalendu; Balachandran, A. P.

    2017-10-01

    In a matrix model of pure SU(2) Yang-Mills theory, boundaries emerge in the space of Mat3(R ) and the Hamiltonian requires boundary conditions. We show the existence of edge localized glueball states that can have negative energies. These edge levels can be lifted to positive energies if the gluons acquire a London-like mass. This suggests a new phase of QCD with an incompressible bulk.

  1. Flexible Edge Nodes enabled by Hybrid Software Defined Optics & Networking

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Mehmeri, Victor; Tafur Monroy, Idelfonso

    This paper presents our vision on flexible edge nodes for future networks and our efforts to combine software defined optics and software defined networking to optimize the overall performance and user experience.......This paper presents our vision on flexible edge nodes for future networks and our efforts to combine software defined optics and software defined networking to optimize the overall performance and user experience....

  2. Phosphorus K-edge XANES spectroscopy of mineral standards

    OpenAIRE

    Ingall, Ellery D.; Brandes, Jay A.; Diaz, Julia M.; de Jonge, Martin D.; Paterson, David; McNulty, Ian; Elliott, W. Crawford; Northrup, Paul

    2010-01-01

    Phosphorus K-edge X-ray absorption near-edge structure (XANES) spectroscopy was performed on phosphate mineral specimens including (a) twelve specimens from the apatite group covering a range of compositional variation and crystallinity; (b) six non-apatite calcium-rich phosphate minerals; (c) 15 aluminium-rich phosphate minerals; (d) ten phosphate minerals rich in either reduced iron or manganese; (e) four phosphate minerals rich in either oxidized iron or manganese; (f) eight phosphate mine...

  3. Study on Trailing Edge Ramp of Supercritical Airfoil

    Science.gov (United States)

    2016-03-30

    7 th Asia-Pacific International Symposium on Aerospace Technology, 25 – 27 November 2015, Cairns Study on Trailing Edge Ramp of Supercritical...separation bubble near the trailing edge. However, the present CFD result shows that it seems a pressure ramp without separation gains better...11372160). 2 Corresponding author. E-mail: chenhaixin@tsinghua.edu.cn 7 th Asia-Pacific International Symposium on Aerospace Technology, 25 – 27

  4. One-sided interval edge-colorings of bipartite graphs

    DEFF Research Database (Denmark)

    Casselgren, Carl Johan; Toft, Bjarne

    2016-01-01

    Let G be a bipartite graph with parts X and Y . An X-interval coloring of G is a proper edge coloring of G by integers such that the colors on the edges incident to any vertex in X form an interval. Denote by χ′int(G,X) the minimum k such that G has an X-interval coloring with k colors. In this p...

  5. Trailing Edge Noise Model Validation and Application to Airfoil Optimization

    DEFF Research Database (Denmark)

    Bertagnolio, Franck; Aagaard Madsen, Helge; Bak, Christian

    2010-01-01

    The aim of this article is twofold. First, an existing trailing edge noise model is validated by comparing with airfoil surface pressure fluctuations and far field sound pressure levels measured in three different experiments. The agreement is satisfactory in one case but poor in two other cases...... across the boundary layer near the trailing edge and to a lesser extent by a smaller boundary layer displacement thickness. ©2010 American Society of Mechanical Engineers...

  6. Spintronic properties of zigzag-edged triangular graphene flakes

    OpenAIRE

    Şahin, Hasan; Senger, Ramazan Tuğrul; Çıracı, Salim

    2010-01-01

    We investigate quantum transport properties of triangular graphene flakes with zigzag edges by using first principles calculations. Triangular graphene flakes have large magnetic moments which vary with the number of hydrogen atoms terminating its edge atoms and scale with its size. Electronic transmission and current-voltage characteristics of these flakes, when contacted with metallic electrodes, reveal spin valve and remarkable rectification features. The transition from ferromagnetic to a...

  7. Implementation of the new multichannel X-mode edge density profile reflectometer for the ICRF antenna on ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Aguiam, D. E., E-mail: daguiam@ipfn.tecnico.ulisboa.pt; Silva, A.; Carvalho, P. J.; Carvalho, P. F.; Fernandes, A.; Gonçalves, B.; Guimarais, L.; Meneses, L.; Pereira, R. C.; Santos, J. M. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal); Bobkov, V.; Conway, G. D.; Faugel, H.; Fünfgelder, H. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany); Cavazzana, R.; De Masi, G. [Consorzio RFX (CNR, ENEA, INFN, Universitá di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); D’Arcangelo, O.; Rocchi, G.; Tuccillo, A. A. [ENEA, Dipartimento FSN, C. R. Frascati, Via E. Fermi 45, 00044 Frascati, Roma (Italy); and others

    2016-11-15

    A new multichannel frequency modulated continuous-wave reflectometry diagnostic has been successfully installed and commissioned on ASDEX Upgrade to measure the plasma edge electron density profile evolution in front of the Ion Cyclotron Range of Frequencies (ICRF) antenna. The design of the new three-strap ICRF antenna integrates ten pairs (sending and receiving) of microwave reflectometry antennas. The multichannel reflectometer can use three of these to measure the edge electron density profiles up to 2 × 10{sup 19} m{sup −3}, at different poloidal locations, allowing the direct study of the local plasma layers in front of the ICRF antenna. ICRF power coupling, operational effects, and poloidal variations of the plasma density profile can be consistently studied for the first time. In this work the diagnostic hardware architecture is described and the obtained density profile measurements were used to track outer radial plasma position and plasma shape.

  8. Impact of interventional edge-to-edge repair on mitral valve geometry.

    Science.gov (United States)

    Schueler, Robert; Kaplan, Sarah; Melzer, Charlotte; Öztürk, Can; Weber, Marcel; Sinning, Jan-Malte; Welz, Armin; Werner, Nikos; Nickenig, Georg; Hammerstingl, Christoph

    2017-03-01

    The acute and long-term effects of interventional edge-to-edge repair on the mitral valve (MV) geometry are unclear. We sought to assess MV-annular geometry and the association of changes in MV-diameters with functional response one year after MitraClip implantation. Consecutive patients (n=84; age 81.2±8.3years, logistic EuroSCORE 21.7±17.9%) with symptomatic moderate-to-severe mitral regurgitation (MR) underwent MitraClip-procedure. MV-annular geometry was assessed with 3D TOE before, immediately and one year after clip implantation. 96.7% of secondary mitral regurgitation (SMR) patients presented with moderate-to-severe MR, 3.3% with severe SMR, respectively. 66.7% of primary MR (PMR) patients had moderate-to-severe MR, and 33.3% severe PMR respectively. When analyzing immediate effects of MitraClipC on mitral geometry, only patients with SMR (n=60, 71.4%) experienced significant reductions of the diastolic MV anterior-posterior diameters (AP: 3.9±0.5cm, 3.5±0.7cm; pgeometry were not significantly altered in patients with PMR (p>0.05). After one year of follow-up, MV annular parameters remained significantly reduced in SMR patients (p0.05). Only SMR patients experienced significant increase in 6min walking distances (p=0.004), decrease in pulmonary pressures (p=0.007) and functional NYHA-class (pgeometry in patients with SMR with stable results after 12months. Reduction of MV-annular dimensions was associated with higher rates of persisting MR reduction and better functional status in patients with SMR. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Na-Montmorillonite Edge Structure and Surface Complexes: An Atomistic Perspective

    National Research Council Canada - National Science Library

    Aric G Newton; Jin-Yong Lee; Kideok D Kwon

    2017-01-01

    The edges of montmorillonite (MMT) react strongly with metals and organic matter, but the atomic structure of the edge and its surface complexes are not unambiguous since the experimental isolation of the edge is challenging...

  10. Symmetric airfoil geometry effects on leading edge noise.

    Science.gov (United States)

    Gill, James; Zhang, X; Joseph, P

    2013-10-01

    Computational aeroacoustic methods are applied to the modeling of noise due to interactions between gusts and the leading edge of real symmetric airfoils. Single frequency harmonic gusts are interacted with various airfoil geometries at zero angle of attack. The effects of airfoil thickness and leading edge radius on noise are investigated systematically and independently for the first time, at higher frequencies than previously used in computational methods. Increases in both leading edge radius and thickness are found to reduce the predicted noise. This noise reduction effect becomes greater with increasing frequency and Mach number. The dominant noise reduction mechanism for airfoils with real geometry is found to be related to the leading edge stagnation region. It is shown that accurate leading edge noise predictions can be made when assuming an inviscid meanflow, but that it is not valid to assume a uniform meanflow. Analytic flat plate predictions are found to over-predict the noise due to a NACA 0002 airfoil by up to 3 dB at high frequencies. The accuracy of analytic flat plate solutions can be expected to decrease with increasing airfoil thickness, leading edge radius, gust frequency, and Mach number.

  11. Edge compression techniques for visualization of dense directed graphs.

    Science.gov (United States)

    Dwyer, Tim; Henry Riche, Nathalie; Marriott, Kim; Mears, Christopher

    2013-12-01

    We explore the effectiveness of visualizing dense directed graphs by replacing individual edges with edges connected to 'modules'-or groups of nodes-such that the new edges imply aggregate connectivity. We only consider techniques that offer a lossless compression: that is, where the entire graph can still be read from the compressed version. The techniques considered are: a simple grouping of nodes with identical neighbor sets; Modular Decomposition which permits internal structure in modules and allows them to be nested; and Power Graph Analysis which further allows edges to cross module boundaries. These techniques all have the same goal--to compress the set of edges that need to be rendered to fully convey connectivity--but each successive relaxation of the module definition permits fewer edges to be drawn in the rendered graph. Each successive technique also, we hypothesize, requires a higher degree of mental effort to interpret. We test this hypothetical trade-off with two studies involving human participants. For Power Graph Analysis we propose a novel optimal technique based on constraint programming. This enables us to explore the parameter space for the technique more precisely than could be achieved with a heuristic. Although applicable to many domains, we are motivated by--and discuss in particular--the application to software dependency analysis.

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

    Science.gov (United States)

    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.

  13. Multi-agent fare optimization model of two modes problem and its analysis based on edge of chaos

    Science.gov (United States)

    Li, Xue-yan; Li, Xue-mei; Li, Xue-wei; Qiu, He-ting

    2017-03-01

    This paper proposes a new framework of fare optimization & game model for studying the competition between two travel modes (high speed railway and civil aviation) in which passengers' group behavior is taken into consideration. The small-world network is introduced to construct the multi-agent model of passengers' travel mode choice. The cumulative prospect theory is adopted to depict passengers' bounded rationality, the heterogeneity of passengers' reference point is depicted using the idea of group emotion computing. The conceptions of "Langton parameter" and "evolution entropy" in the theory of "edge of chaos" are introduced to create passengers' "decision coefficient" and "evolution entropy of travel mode choice" which are used to quantify passengers' group behavior. The numerical simulation and the analysis of passengers' behavior show that (1) the new model inherits the features of traditional model well and the idea of self-organizing traffic flow evolution fully embodies passengers' bounded rationality, (2) compared with the traditional model (logit model), when passengers are in the "edge of chaos" state, the total profit of the transportation system is higher.

  14. Engineering the Edges of MoS2 (WS2) Crystals for Direct Exfoliation into Monolayers in Polar Micromolecular Solvents.

    Science.gov (United States)

    Hai, Xiao; Chang, Kun; Pang, Hong; Li, Mu; Li, Peng; Liu, Huimin; Shi, Li; Ye, Jinhua

    2016-11-16

    Synthesizing transition metal dichalcogenide (TMDC) monolayers through the liquid exfoliation of bulk crystals in low boiling point polar micromolecular solvents, such as water, is paramount for their practical application. However, the resulting hydrodynamic forces only appear on the crystal edges due to the mismatch in surface tension between the polar micromolecular solvents and the bulk crystals and are insufficient to overcome the strong van der Waals attraction between adjacent microscale layers. Herein, we present the novel strategy of engineering the lateral size of TMDC (MoS2 and WS2) crystals in the nanoscale to increase the fraction of edges, leading to their direct and ready exfoliation in polar micromolecular solvents, even in pure water, to produce monolayer MoS2 and WS2 nanosheets in high yield. To examine one of their important applications, their catalytic hydrogen evolution activities were evaluated when used as cocatalysts with a photoharvester semiconductor (cadmium sulfide, CdS) in a reaction driven by solar energy. These exfoliated MoS2 (WS2) monolayers exhibited superior cocatalytic performance in the photocatalytic hydrogen evolution reaction (HER). Notably, the cocatalytic performance of monolayer WS2 nanosheets is even higher than that of platinum (Pt), which is a state-of-the-art catalyst for catalytic hydrogen evolution. This work elucidates the importance of decreasing the lateral size of layered crystals to significantly enhance their exfoliability, providing a new strategy for the large-scale preparation of nanoscale TMDC monolayers by liquid exfoliation.

  15. Rapid adaptive evolution in novel environments acts as an architect of population range expansion.

    Science.gov (United States)

    Szűcs, M; Vahsen, M L; Melbourne, B A; Hoover, C; Weiss-Lehman, C; Hufbauer, R A

    2017-12-19

    Colonization and expansion into novel landscapes determine the distribution and abundance of species in our rapidly changing ecosystems worldwide. Colonization events are crucibles for rapid evolution, but it is not known whether evolutionary changes arise mainly after successful colonization has occurred, or if evolution plays an immediate role, governing the growth and expansion speed of colonizing populations. There is evidence that spatial evolutionary processes can speed range expansion within a few generations because dispersal tendencies may evolve upwards at range edges. Additionally, rapid adaptation to a novel environment can increase population growth rates, which also promotes spread. However, the role of adaptive evolution and the relative contributions of spatial evolution and adaptation to expansion are unclear. Using a model system, red flour beetles (Tribolium castaneum), we either allowed or constrained evolution of populations colonizing a novel environment and measured population growth and spread. At the end of the experiment we assessed the fitness and dispersal tendency of individuals originating either from the core or edge of evolving populations or from nonevolving populations in a common garden. Within six generations, evolving populations grew three times larger and spread 46% faster than populations in which evolution was constrained. Increased size and expansion speed were strongly driven by adaptation, whereas spatial evolutionary processes acting on edge subpopulations contributed less. This experimental evidence demonstrates that rapid evolution drives both population growth and expansion speed and is thus crucial to consider for managing biological invasions and successfully introducing or reintroducing species for management and conservation.

  16. A weighted network model for interpersonal relationship evolution

    Science.gov (United States)

    Hu, Bo; Jiang, Xin-Yu; Ding, Jun-Feng; Xie, Yan-Bo; Wang, Bing-Hong

    2005-08-01

    A simple model is proposed to mimic and study the evolution of interpersonal relationships in a student class. The small social group is simply assumed as an undirected and weighted graph, in which students are represented by vertices, and the depth of favor or disfavor between them are denoted by the corresponding edge weight. In our model, we find that the first impression between people has a crucial influence on the final status of student relations (i.e., the final distribution of edge weights). The system displays a phase transition in the final hostility proportion depending on the initial amity possibility. We can further define the strength of vertices to describe the individual popularity, which exhibits nonlinear evolution. Meanwhile, various nonrandom perturbations to the initial system have been investigated, and simulation results are in accord with common real-life observations.

  17. Validation of Kinetic-Turbulent-Neoclassical Theory for Edge Intrinsic Rotation in DIII-D Plasmas

    Science.gov (United States)

    Ashourvan, Arash

    2017-10-01

    Recent experiments on DIII-D with low-torque neutral beam injection (NBI) have provided a validation of a new model of momentum generation in a wide range of conditions spanning L- and H-mode with direct ion and electron heating. A challenge in predicting the bulk rotation profile for ITER has been to capture the physics of momentum transport near the separatrix and steep gradient region. A recent theory has presented a model for edge momentum transport which predicts the value and direction of the main-ion intrinsic velocity at the pedestal-top, generated by the passing orbits in the inhomogeneous turbulent field. In this study, this model-predicted velocity is tested on DIII-D for a database of 44 low-torque NBI discharges comprised of bothL- and H-mode plasmas. For moderate NBI powers (PNBInet injected torque through the edge can exceed 1 N.m in the counter-current direction. The theory model has been extended to compute the rotation degradation from this counter-current NBI torque by solving a reduced momentum evolution equation for the edge and found the revised velocity prediction to be in agreement with experiment. Projecting to the ITER baseline scenario, this model predicts a value for the pedestal-top rotation (ρ 0.9) comparable to 4 kRad/s. Using the theory modeled - and now tested - velocity to predict the bulk plasma rotation opens up a path to more confidently projecting the confinement and stability in ITER. Supported by the US DOE under DE-AC02-09CH11466 and DE-FC02-04ER54698.

  18. Oscillations of a Turbulent Jet Incident Upon an Edge

    Energy Technology Data Exchange (ETDEWEB)

    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

  19. Anomalous diffusion, clustering, and pinch of impurities in plasma edge turbulence

    DEFF Research Database (Denmark)

    Priego, M.; Garcia, O.E.; Naulin, V.

    2005-01-01

    The turbulent transport of impurity particles in plasma edge turbulence is investigated. The impurities are modeled as a passive fluid advected by the electric and polarization drifts, while the ambient plasma turbulence is modeled using the two-dimensional Hasegawa-Wakatani paradigm for resistive...... drift-wave turbulence. The features of the turbulent transport of impurities are investigated by numerical simulations using a novel code that applies semi-Lagrangian pseudospectral schemes. The diffusive character of the turbulent transport of ideal impurities is demonstrated by relative......-diffusion analysis of the evolution of impurity puffs. Additional effects appear for inertial impurities as a consequence of compressibility. First, the density of inertial impurities is found to correlate with the vorticity of the electric drift velocity, that is, impurities cluster in vortices of a precise...

  20. Interplay between bulk and edge-bound topological defects in a square micromagnet

    Science.gov (United States)

    Sloetjes, Sam D.; Digernes, Einar; Olsen, Fredrik K.; Chopdekar, Rajesh V.; Retterer, Scott T.; Folven, Erik; Grepstad, Jostein K.

    2018-01-01

    A field-driven transformation of a domain pattern in a square micromagnet, defined in a thin film of La0.7Sr0.3MnO3, is discussed in terms of creation and annihilation of bulk vortices and edge-bound topological defects with half-integer winding numbers. The evolution of the domain pattern was mapped with soft x-ray photoemission electron microscopy and magnetic force microscopy. Micromagnetic modeling, permitting detailed analysis of the spin texture, accurately reproduces the measured domain state transformation. The simulations also helped stipulate the energy barriers associated with the creation and annihilation of the topological charges and thus to assess the stability of the domain states in this magnetic microstructure.

  1. Formation of spiral structures and radial convection in the edge region of a magnetized rotating plasma

    Energy Technology Data Exchange (ETDEWEB)

    Barni, R [Dipartimento di Fisica Occhialini, Universita degli Studi di Milano-Bicocca, p.za della Scienza 3, 20126 Milan (Italy); Riccardi, C [Dipartimento di Fisica Occhialini, Universita degli Studi di Milano-Bicocca, p.za della Scienza 3, 20126 Milan (Italy); Pierre, Th [Laboratoire PIIM, UMR 6633, CNRS et Universite de Provence, 13397 Marseille Cedex 20 (France); Leclert, G [Laboratoire PIIM, UMR 6633, CNRS et Universite de Provence, 13397 Marseille Cedex 20 (France); Escarguel, A [Laboratoire PIIM, UMR 6633, CNRS et Universite de Provence, 13397 Marseille Cedex 20 (France); Guyomarc' h, D [Laboratoire PIIM, UMR 6633, CNRS et Universite de Provence, 13397 Marseille Cedex 20 (France); Quotb, K [Laboratoire PIIM, UMR 6633, CNRS et Universite de Provence, 13397 Marseille Cedex 20 (France)

    2005-10-15

    The rotation of a cylindrical plasma column in a magnetic field has been studied in the linear section of the new plasma device Mistral. Under suitable conditions we observe a transition to a turbulent regime characterized by strong, bursty fluctuations at the edge of the column. The detection and the study of the spatio-temporal evolution of structures in the turbulent regime have been performed by means of a new enhanced conditional sampling technique. We have collected evidence of the development of a bent tail emanating from the plasma column. The charged particles inside the structure move along a spiral trajectory resulting in a net radial convection of the plasma to the walls. We show experimentally that a poloidal electric field is present inside the structures leading to the observed outwards radial E x B drift, in agreement with the expectations of recent and past theoretical works.

  2. Propagation of a Dugdale crack at the edge of a half plane

    Science.gov (United States)

    Ferdjani, Hicheme; Abdelmoula, Radhi

    2018-01-01

    This work deals with the propagation of a Dugdale crack at the edge of a half plane. The corresponding singular integral equation is solved semi-analytically. The expressions of the stress intensity factor and of the crack gap are deduced. A propagation criterion deduced from the revisited Griffith theory (Ferdjani and Marigo in Eur J Mech A Solids 53:1-9, 2015) is applied. The length of the process zone is calculated and compared with the literature results. The presented results show the evolution of the applied load with the crack length for different values of the ratio of the critical length of the Dugdale model to the initial crack length. The shape of the crack gap is also presented. Finally, a comparison between the Griffith and Dugdale models is performed.

  3. Pure spin current induced by adiabatic quantum pumping in zigzag-edged graphene nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Souma, Satofumi, E-mail: ssouma@harbor.kobe-u.ac.jp; Ogawa, Matsuto [Department of Electrical and Electronic Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan)

    2014-05-05

    We show theoretically that pure spin current can be generated in zigzag edged graphene nanoribbons through the adiabatic pumping by edge selective pumping potentials. The origin of such pure spin current is the spin splitting of the edge localized states, which are oppositely spin polarized at opposite edges. In the proposed device, each edge of the ribbon is covered by two independent time-periodic local gate potentials with a definite phase difference, inducing the edge spin polarized current. When the pumping phase difference is opposite in sign between two edges, the total charge currents is zero and the pure edge spin current is generated.

  4. Origin of the pre-edge structure at the Al K-edge: The role of atomic vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Cabaret, Delphine; Brouder, Christian, E-mail: Delphine.Cabaret@impmc.jussieu.f [Institut de Mineralogie et Physique des Milieux Condenses, UMR 7590 CNRS, Universite Pierre et Marie Curie, Universite Paris Diderot, IPGP, IRD, 140 rue de Lourmel, 75015 Paris (France)

    2009-11-15

    We present a detailed analysis of the pre-edge peak present in the Al K-edge XANES spectra of corundum ({alpha}-Al{sub 2}O{sub 3}) and diaspore ({alpha}-AlOOH), as measured at room temperature. This is achieved by XANES and DOS calculations performed using the density functional theory in a pseudopotential plane-wave framework. The XANES calculations carried out for the equilibrium atomic positions do not reproduce the pre-edge of corundum and partially reproduce it in the case of diaspore. It is shown that the electronic transitions occuring in the pre-edge involves the 3s empty states of the aluminium absorbing atom. The Al 3s states can be probed in the electric dipole approximation via a p-s mixing, which is possible only if the Al site is not centrosymmetric. Although Al does not occupy an inversion center in the two minerals under study, the p-s mixing is too weak to provide a pre-edge feature in good agreement with experiment. The deviation from centrosymmetry can be enhanced by the atomic vibrations. We develop a theory that takes into account the atomic vibrations directly in the calculation of the absorption cross section, based on the Born-Oppenheimer approximation. This theory is applied to corundum and diaspore and yields satisfactory results in the pre-edge region.

  5. Tongues on the EDGE: language preservation priorities based on threat and lexical distinctiveness.

    Science.gov (United States)

    Perrault, Nicolas; Farrell, Maxwell J; Davies, T Jonathan

    2017-12-01

    Languages are being lost at rates exceeding the global loss of biodiversity. With the extinction of a language we lose irreplaceable dimensions of culture and the insight it provides on human history and the evolution of linguistic diversity. When setting conservation goals, biologists give higher priority to species likely to go extinct. Recent methods now integrate information on species evolutionary relationships to prioritize the conservation of those with a few close relatives. Advances in the construction of language trees allow us to use these methods to develop language preservation priorities that minimize loss of linguistic diversity. The evolutionarily distinct and globally endangered (EDGE) metric, used in conservation biology, accounts for a species' originality (evolutionary distinctiveness-ED) and its likelihood of extinction (global endangerment-GE). Here, we use a similar framework to inform priorities for language preservation by generating rankings for 350 Austronesian languages. Kavalan, Tanibili, Waropen and Sengseng obtained the highest EDGE scores, while Xârâcùù (Canala), Nengone and Palauan are among the most linguistically distinct, but are not currently threatened. We further provide a way of dealing with incomplete trees, a common issue for both species and language trees.

  6. Filamentary Alfvénic structures excited at the edges of equatorial plasma bubbles

    Directory of Open Access Journals (Sweden)

    R. Pottelette

    2007-11-01

    Full Text Available Recent observations performed by the French DEMETER satellite at altitudes of about 710 km suggest that the generation of equatorial plasma bubbles correlates with the presence of filamentary structures of field aligned currents carried by Alfvén waves. These localized structures are located at the bubble edges. We study the dynamics of the equatorial plasma bubbles, taking into account that their motion is dictated by gravity driven and displacement currents. Ion-polarization currents appear to be crucial for the accurate description of the evolution of plasma bubbles in the high altitude ionosphere. During their eastward/westward motion the bubbles intersect gravity driven currents flowing transversely with respect to the background magnetic field. The circulation of these currents is prohibited by large density depressions located at the bubble edges acting as perfect insulators. As a result, in these localized regions the transverse currents have to be locally closed by field aligned currents. Such a physical process generates kinetic Alfvén waves which appear to be stationary in the plasma bubble reference frame. Using a two-dimensional model and "in situ" wave measurements on board the DEMETER spacecraft, we give estimates for the magnitude of the field aligned currents and the associated Alfvén fields.

  7. The evolution of senescence in the tree of life

    DEFF Research Database (Denmark)

    Salguero-Gómez, Roberto

    The existing theories on the evolution of senescence assume that senescence is inevitable in all organisms. However, recent studies have shown that this is not necessarily true. A better understanding of senescence and its underlying mechanisms could have far-reaching consequences for conservation...... and eco-evolutionary research. This book is the first to offer interdisciplinary perspectives on the evolution of senescence in many species, setting the stage for further developments. It brings together new insights from a wide range of scientific fields and cutting-edge research done on a multitude...

  8. The evolution of cooperation on geographical networks

    Science.gov (United States)

    Li, Yixiao; Wang, Yi; Sheng, Jichuan

    2017-11-01

    We study evolutionary public goods game on geographical networks, i.e., complex networks which are located on a geographical plane. The geographical feature effects in two ways: In one way, the geographically-induced network structure influences the overall evolutionary dynamics, and, in the other way, the geographical length of an edge influences the cost when the two players at the two ends interact. For the latter effect, we design a new cost function of cooperators, which simply assumes that the longer the distance between two players, the higher cost the cooperator(s) of them have to pay. In this study, network substrates are generated by a previous spatial network model with a cost-benefit parameter controlling the network topology. Our simulations show that the greatest promotion of cooperation is achieved in the intermediate regime of the parameter, in which empirical estimates of various railway networks fall. Further, we investigate how the distribution of edges' geographical costs influences the evolutionary dynamics and consider three patterns of the distribution: an approximately-equal distribution, a diverse distribution, and a polarized distribution. For normal geographical networks which are generated using intermediate values of the cost-benefit parameter, a diverse distribution hinders the evolution of cooperation, whereas a polarized distribution lowers the threshold value of the amplification factor for cooperation in public goods game. These results are helpful for understanding the evolution of cooperation on real-world geographical networks.

  9. EDgE multi-model hydro-meteorological seasonal hindcast experiments over Europe

    Science.gov (United States)

    Samaniego, Luis; Thober, Stephan; Kumar, Rohini; Rakovec, Oldrich; Wood, Eric; Sheffield, Justin; Pan, Ming; Wanders, Niko; Prudhomme, Christel

    2017-04-01

    Extreme hydrometeorological events (e.g., floods, droughts and heat waves) caused serious damage to society and infrastructures over Europe during the past decades. Developing a seamless and skillful operational seasonal forecasting system of these extreme events is therefore a key tool for short-term decision making at local and regional scales. The EDgE project funded by the Copernicus programme (C3S) provides an unique opportunity to investigate the skill of a newly created large multi-model hydro-meteorological ensemble for predicting extreme events over the Pan-EU domain at a higher resolution 5×5 km2. Two state-of-the-art seasonal prediction systems were chosen for this project. Two models from the North American MultiModel ensemble (NMME) with 22 realizations, and two models provided by the ECMWF with 30 realizations. All models provide daily forcings (P, Ta, Tmin, Tmax) of the the Pan-EU at 1°. Downscaling has been carried out with the MTCLIM algorithm (Bohn et al. 2013) and external drift Kriging using elevation as drift to induce orographic effects. In this project, four high-resolution seamless hydrologic simulations with the mHM (www.ufz.de/mhm), Noah-MP, VIC and PCR-GLOBWB have been completed for the common hindcast period of 1993-2012 resulting in an ensemble size of 208 realizations. Key indicators are focussing on six terrestrial Essential Climate Variables (tECVs): river runoff, soil moisture, groundwater recharge, precipitation, potential evapotranspiration, and snow water equivalent. Impact Indicators have been co-designed with stakeholders in Norway (hydro-power), UK (water supply), and Spain (river basin authority) to provide an improved information for decision making. The Indicators encompass diverse information such as the occurrence of high and low streamflow percentiles (floods, and hydrological drought) and lower percentiles of top soil moisture (agricultural drought) among others. Preliminary results evaluated at study sites in Norway

  10. Oxygen and Biological Evolution.

    Science.gov (United States)

    Baugh, Mark A.

    1990-01-01

    Discussed is the evolution of aerobic organisms from anaerobic organisms and the accompanying biochemistry that developed to motivate and enable this evolution. Uses of oxygen by aerobic organisms are described. (CW)

  11. Cannabis: evolution and ethnobotany

    National Research Council Canada - National Science Library

    Clarke, Robert Connell; Merlin, Mark David

    2013-01-01

    "Cannabis: Evolution and Ethnobotany is a comprehensive, interdisciplinary exploration of the natural origins and early evolution of this famous plant, highlighting its historic role in the development of human societies...

  12. The Evolution of Design

    Science.gov (United States)

    Stebbins, G. Ledyard

    1973-01-01

    Describes the basic logic behind the modern view of evolution theory. Despite gaps in fossil records, evidence is indicative of the origin of life from nonliving molecules and evolution of higher forms of life from simpler forms. (PS)

  13. Inlet Geomorphology Evolution

    Science.gov (United States)

    2015-04-01

    APR 2015 2. REPORT TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Inlet Geomorphology Evolution 5a. CONTRACT NUMBER 5b...Std Z39-18 Coastal Inlets Research Program Inlet Geomorphology Evolution The Inlet Geomorphology Evolution work unit of the CIRP evaluates

  14. Characterizing Polar Mesospheric Summer Echo Edge Effect Formation

    Science.gov (United States)

    Yee, J.; Bahcivan, H.

    2013-12-01

    Polar Mesospheric Summer Echoes (PMSEs) form in the summer mesopause region, between altitudes of 80 and 90 km. This phenomenon occurs in this region because of the extremely cold temperatures that allow for ice particles to develop, sediment, and grow to sizes as large as ~20 nm. Because these ice particles are immersed in the plasma of the D-region, electrons can attach to the ice surfaces and charge them. There are two trains of thought when it comes to the backscatter seen in sounding rocket and radar measurements of PMSEs. The first assumes that the structure of the PMSEs is driven by turbulent velocity fields and that radar detections are due to turbulent scattering. The second theory on the scatter from PMSE structures is that the echoes result from multiple sharp small-scale ledges that produce an edge scatter. In decomposing sounding rocket data, results have indicated that both scattering mechanisms play a role in PMSE backscatter. However, whereas the turbulent scatter theory is well developed, the physics behind the sharp-edge phenomena in the edge scattering theory has not been explained to date. We investigate the formation of the sharp edges in electron density detected by sounding rockets and in backscattered power detected by ground-based radars during PMSE regions by exploring the initial process by which PMSEs form using a one dimensional (1D) particle-in-cell (PIC) simulation. The simulation, adapted from the Plasma Theory and Simulation Group at UC Berkley, starts with the ice particles immersed in a warm electron-ion plasma and allows for the charging process of the ice particles. Starting with an initial Gaussian distribution of ice particles, we show that as the ice particles charge, they increase in mass more quickly (i.e. accumulate more electrons and ions) at the edges of the PMSE structure. This increased mass decreases the diffusion rates of the edges and 'freezes' the edges of the PMSE. This result demonstrates that the reason for the

  15. Laser speckle reduction based on compressive sensing and edge detection

    Science.gov (United States)

    Wen, Dong-hai; Jiang, Yue-song; Hua, Hou-qiang; Yu, Rong; Gao, Qian; Zhang, Yan-zhong

    2013-09-01

    Polarization active imager technology obtains images encoded by parameters different than just the reflectivity and therefore provides new information on the image. So polarization active imager systems represent a very powerful observation tool. However, automatic interpretation of the information contained in the reflected intensity of the polarization active image data is extremely difficult because of the speckle phenomenon. An approach for speckle reduction of polarization active image based on the concepts of compressive sensing (CS) theory and edge detection. First, A Canny operator is first utilized to detect and remove edges from the polarization active image. Then, a dictionary learning algorithm which is applied to sparse image representation. The dictionary learning problem is expressed as a box-constrained quadratic program and a fast projected gradient method is introduced to solve it. The Gradient Projection for Square Reconstruction (GPSR) algorithm for solving bound constrained quadratic programming to reduce the speckle noise in the polarization active images. The block-matching 3-D (BM3D) algorithm is used to reduce speckle nosie, it works in two steps: The first one uses hard thresholding to build a relatively clean image for estimating statistics, while the second one performs the actual denoising through empirical Wiener filtering in the transform domain. Finally, the removed edges are added to the reconstructed image. Experimental results show that the visual quality and evaluation indexes outperform the other methods with no edge preservation. The proposed algorithm effectively realizes both despeckling and edge preservation and reaches the state-of-the-art performance.

  16. Automatic comic page image understanding based on edge segment analysis

    Science.gov (United States)

    Liu, Dong; Wang, Yongtao; Tang, Zhi; Li, Luyuan; Gao, Liangcai

    2013-12-01

    Comic page image understanding aims to analyse the layout of the comic page images by detecting the storyboards and identifying the reading order automatically. It is the key technique to produce the digital comic documents suitable for reading on mobile devices. In this paper, we propose a novel comic page image understanding method based on edge segment analysis. First, we propose an efficient edge point chaining method to extract Canny edge segments (i.e., contiguous chains of Canny edge points) from the input comic page image; second, we propose a top-down scheme to detect line segments within each obtained edge segment; third, we develop a novel method to detect the storyboards by selecting the border lines and further identify the reading order of these storyboards. The proposed method is performed on a data set consisting of 2000 comic page images from ten printed comic series. The experimental results demonstrate that the proposed method achieves satisfactory results on different comics and outperforms the existing methods.

  17. Sudden distortion of turbulence at a forest edge

    Science.gov (United States)

    Mann, J.; Dellwik, E.

    2014-06-01

    Dellwik et al. (2013) presented data from a forest edge experiment based on two meteorological towers instrumented with sonic anemometers. The experiment was performed at a dense edge of the Tromnæs Forest, which is a 24 m tall mature beech stand on the island Falster, Denmark. The topography at the site is flat. The towers were placed approximately 1.5 canopy heights upwind and downwind of the edge, respectively, and were two canopy heights tall. For near-neutral, near-perpendicular flow towards the edge, one finding concerned that although the wind speed gradients were similar before and after the edge, the momentum flux was strongly reduced above the canopy. This is contrary to the results by standard Reynolds' averaged Navier-Stokes models that predict an overshoot of the momentum flux. Further, a reduction of the vertical variance of the flow was largely compensated by an increase in the lateral variance, whereas the streamwise variance remained approximately constant. This result is in contrast to the predictions by homogeneous rapid distortion theory. We apply and develop an alternative framework based on inhomogeneous rapid distortion theory, also called blocking, in combination with the turbulence model by Mann (1994), and investigate whether this model can predict the observed changes of the flow. The presented results are relevant for understanding the rapid changes of turbulence in the heterogeneous landscape.

  18. Improvement of airfoil trailing edge bluntness noise model

    Directory of Open Access Journals (Sweden)

    Wei Jun Zhu

    2016-02-01

    Full Text Available In this article, airfoil trailing edge bluntness noise is investigated using both computational aero-acoustic and semi-empirical approach. For engineering purposes, one of the most commonly used prediction tools for trailing edge noise are based on semi-empirical approaches, for example, the Brooks, Pope, and Marcolini airfoil noise prediction model developed by Brooks, Pope, and Marcolini (NASA Reference Publication 1218, 1989. It was found in previous study that the Brooks, Pope, and Marcolini model tends to over-predict noise at high frequencies. Furthermore, it was observed that this was caused by a lack in the model to predict accurately noise from blunt trailing edges. For more physical understanding of bluntness noise generation, in this study, we also use an advanced in-house developed high-order computational aero-acoustic technique to investigate the details associated with trailing edge bluntness noise. The results from the numerical model form the basis for an improved Brooks, Pope, and Marcolini trailing edge bluntness noise model.

  19. Naegleria fowleri: contact-dependent secretion of electrondense granules (EDG).

    Science.gov (United States)

    Chávez-Munguía, Bibiana; Villatoro, Lizbeth Salazar; Omaña-Molina, Maritza; Rodríguez-Monroy, Marco Aurelio; Segovia-Gamboa, Norma; Martínez-Palomo, Adolfo

    2014-07-01

    The free living amoeba Naegleria fowleri is pathogenic to humans but also to other mammalians. These amoebae may invade the nasal mucosa and migrate into the brain causing cerebral hemorrhagic necrosis, a rapidly fatal infection. Knowledge of the cytolytic mechanism involved in the destruction of brain tissues by Naegleria trophozoites is limited. In other amoebic species, such as Entamoeba histolytica, we have previously reported the possible lytic role of small cytoplasmic components endowed with proteolytic activities, known as electrondense granules (EDG). Using transmission electron microscopy we now report that EDG, seldom found in long term cultured N. fowleri, are present in abundance in trophozoites recovered from experimental mice brain lesions. Numerous EDG were also observed in amoebae incubated with collagen substrates or cultured epithelial cells. SDS-PAGE assays of concentrated supernatants of these trophozoites, containing EDG, revealed proteolytic activities. These results suggest that EDG may have a clear role in the cytopathic mechanisms of this pathogenic amoeba. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Modeling of Edge Plasma Transport in 3D

    Science.gov (United States)

    Umansky, M. V.; Rognlien, T. D.; Fenstermacher, M. E.; Borchardt, M.; Riemann, J.; Schneider, R.

    2001-10-01

    Two-dimensional fluid codes have become standard modeling tools for scrape-off layer and divertor in tokamaks. Such 2D codes (UEDGE, B2, EDGE2D) solve a reduced set of plasma fluid equations with the assumption of toroidal symmetry. However perfect toroidal symmetry in tokamak edge never holds due to details of plasma facing components. Moreover, with the renewed interest in stellarators with several major experiments under way or planned (W7AS, W7X, LHD, NCSX) there is a demand for 3D modeling tools for the edge plasma. One such tool under development is the 3D fluid edge code BoRiS. (M.Borchardt et al., J. Nucl. Mater., 290-293 (2001) 546-550.) A focus of the present investigation is development and testing robust numerical schemes for edge plasma fluid equations in 3D. This analysis includes benchmarking of BoRiS on sample problems where an exact solution can be found, and benchmarking against a 2D code such as UEDGE for the toroidally symmetric case. We will discuss the options for parallelization of BoRiS which will be necessary for making it a practical tool. Results will be presented for application of BoRiS to the NCSX stellarator geometry, which will provide insight on the design of plasma facing components.

  1. Magnetic X-points, edge localized modes, and stochasticitya)

    Science.gov (United States)

    Sugiyama, L. E.; Strauss, H. R.

    2010-06-01

    Edge localized modes (ELMs) near the boundary of a high temperature, magnetically confined toroidal plasma represent a new type of nonlinear magnetohydrodynamic (MHD) plasma instability that grows through a coherent plasma interaction with part of a chaotic magnetic field. Under perturbation, the freely moving magnetic boundary surface with an X-point splits into two different limiting asymptotic surfaces (manifolds), similar to the behavior of a hyperbolic saddle point in Hamiltonian dynamics. Numerical simulation using the extended MHD code M3D shows that field-aligned plasma instabilities, such as ballooning modes, can couple to the "unstable" manifold that forms helical, field-following lobes around the original surface. Large type I ELMs proceed in stages. Initially, a rapidly growing ballooning outburst involves the entire outboard side. Large plasma fingers grow well off the midplane, while low density regions penetrate deeply into the plasma. The magnetic field becomes superficially stochastic. A secondary inboard edge instability causes inboard plasma loss. The plasma gradually relaxes back toward axisymmetry, with diminishing cycles of edge instability. Poloidal rotation of the interior and edge plasma may be driven. The magnetic tangle constrains the early nonlinear ballooning, but may encourage the later inward penetration. Equilibrium toroidal rotation and two-fluid diamagnetic drifts have relatively small effects on a strong MHD instability. Intrinsic magnetic stochasticity may help explain the wide range of experimentally observed ELMs and ELM-free behavior in fusion plasmas, as well as properties of the H-mode and plasma edge.

  2. Phosphorus K-edge XANES spectroscopy of mineral standards.

    Science.gov (United States)

    Ingall, Ellery D; Brandes, Jay A; Diaz, Julia M; de Jonge, Martin D; Paterson, David; McNulty, Ian; Elliott, W Crawford; Northrup, Paul

    2011-03-01

    Phosphorus K-edge X-ray absorption near-edge structure (XANES) spectroscopy was performed on phosphate mineral specimens including (a) twelve specimens from the apatite group covering a range of compositional variation and crystallinity; (b) six non-apatite calcium-rich phosphate minerals; (c) 15 aluminium-rich phosphate minerals; (d) ten phosphate minerals rich in either reduced iron or manganese; (e) four phosphate minerals rich in either oxidized iron or manganese; (f) eight phosphate minerals rich in either magnesium, copper, lead, zinc or rare-earth elements; and (g) four uranium phosphate minerals. The identity of all minerals examined in this study was independently confirmed using X-ray powder diffraction. Minerals were distinguished using XANES spectra with a combination of pre-edge features, edge position, peak shapes and post-edge features. Shared spectral features were observed in minerals with compositions dominated by the same specific cation. Analyses of apatite-group minerals indicate that XANES spectral patterns are not strongly affected by variations in composition and crystallinity typical of natural mineral specimens.

  3. Surfing the edge: using feedback control to find nonlinear solutions

    Science.gov (United States)

    Willis, A. P.; Duguet, Y.; Omel'chenko, O.; Wolfrum, M.

    2017-11-01

    Many transitional wall-bounded shear flows are characterised by the coexistence in state-space of laminar and turbulent regimes. Probing the edge boundary between the two attractors has led in the last decade to the numerical discovery of new (unstable) solutions to the incompressible Navier-Stokes equations. However, the iterative bisection method used to achieve this can become prohibitively costly for large systems. Here we suggest a simple feedback control strategy to stabilise edge states, hence accelerating their numerical identification by several orders of magnitude. The method is illustrated for several configurations of cylindrical pipe flow. Travelling waves solutions are identified as edge states, and can be isolated rapidly in only one short numerical run. A new branch of solutions is also identified. When the edge state is a periodic orbit or chaotic state, the feedback control does not converge precisely to solutions of the uncontrolled system, but nevertheless brings the dynamics very close to the original edge manifold in a single run. We discuss the opportunities offered by the speed and simplicity of this new method to probe the structure of both state space and parameter space.

  4. Prediction of noise from serrated trailing-edges

    CERN Document Server

    Lyu, B; Sinayoko, S

    2015-01-01

    A new analytical model is developed for the prediction of noise from serrated trailing-edges. The model generalizes Amiet's trailing-edge noise theory to sawtooth trailing-edges, resulting in an inhomogeneous partial differential equation. The equation is then solved by means of a Fourier expansion technique combined with an iterative procedure. The solution is validated through comparison with finite element method for a variety of serrations at different Mach numbers. Results obtained using the new model predict noise reduction of up to 10 dB at 90 degree above the trailing-edge, which is more realistic than predictions based on Howe's model and also more consistent with experimental observations. A thorough analytical and numerical analysis of the physical mechanism is carried out and suggests that the noise reduction due to serration originates primarily from interference effects near the trailing-edge. A closer inspection of the proposed mathematical model has led to the development of two criteria for t...

  5. Habitat heterogeneity hypothesis and edge effects in model metacommunities.

    Science.gov (United States)

    Hamm, Michaela; Drossel, Barbara

    2017-08-07

    Spatial heterogeneity is an inherent property of any living environment and is expected to favour biodiversity due to a broader niche space. Furthermore, edges between different habitats can provide additional possibilities for species coexistence. Using computer simulations, this study examines metacommunities consisting of several trophic levels in heterogeneous environments in order to explore the above hypotheses on a community level. We model heterogeneous landscapes by using two different sized resource pools and evaluate the combined effect of dispersal and heterogeneity on local and regional species diversity. This diversity is obtained by running population dynamics and evaluating the robustness (i.e., the fraction of surviving species). The main results for regional robustness are in agreement with the habitat heterogeneity hypothesis, as the largest robustness is found in heterogeneous systems with intermediate dispersal rates. This robustness is larger than in homogeneous systems with the same total amount of resources. We study the edge effect by arranging the two types of resources in two homogeneous blocks. Different edge responses in diversity are observed, depending on dispersal strength. Local robustness is highest for edge habitats that contain the smaller amount of resource in combination with intermediate dispersal. The results show that dispersal is relevant to correctly identify edge responses on community level. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. The Existence of Topological Edge States in Honeycomb Plasmonic Lattices

    CERN Document Server

    Wang, Li; Xiao, Meng; Han, Dezhuan; Chan, C T; Wen, Weijia

    2016-01-01

    In this paper, we investigate the band properties of 2D honeycomb plasmonic lattices consisting of metallic nanoparticles. By means of the coupled dipole method and quasi-static approximation, we theoretically analyze the band structures stemming from near-field interaction of localized surface plasmon polaritons for both the infinite lattice and ribbons. Naturally, the interaction of point dipoles decouples into independent out-of-plane and in-plane polarizations. For the out-of-plane modes, both the bulk spectrum and the range of the momentum $k_{\\parallel}$ where edge states exist in ribbons are similar to the electronic bands in graphene. Nevertheless, the in-plane polarized modes show significant differences, which do not only possess additional non-flat edge states in ribbons, but also have different distributions of the flat edge states in reciprocal space. For in-plane polarized modes, we derived the bulk-edge correspondence, namely, the relation between the number of flat edge states at a fixed $k_\\p...

  7. Cosine edge modes in a periodically driven quantum system

    Science.gov (United States)

    Satija, Indubala I.; Zhao, Erhai

    2016-12-01

    Time-periodic (Floquet) topological phases of matter exhibit bulk-edge relationships that are more complex than static topological insulators and superconductors. Finding the edge modes unique to driven systems usually requires numerics. Here we present a minimal two-band model of Floquet topological insulators and semimetals in two dimensions where all the bulk and edge properties can be obtained analytically. It is based on the extended Harper model of quantum Hall effect at flux one-half. We show that periodical driving gives rise to a series of phases characterized by a pair of integers. The model has a most striking feature: the spectrum of the edge modes is always given by a single cosine function, ω (ky) ∝cosky where ky is the wave number along the edge, as if it is freely dispersing and completely decoupled from the bulk. The cosine mode is robust against the change in driving parameters. It also persists in the semimetallic phases with Dirac points.

  8. Material Discrimination Based on K-edge Characteristics

    Directory of Open Access Journals (Sweden)

    Peng He

    2013-01-01

    Full Text Available Spectral/multienergy CT employing the state-of-the-art energy-discriminative photon-counting detector can identify absorption features in the multiple ranges of photon energies and has the potential to distinguish different materials based on K-edge characteristics. K-edge characteristics involve the sudden attenuation increase in the attenuation profile of a relatively high atomic number material. Hence, spectral CT can utilize material K-edge characteristics (sudden attenuation increase to capture images in available energy bins (levels/windows to distinguish different material components. In this paper, we propose an imaging model based on K-edge characteristics for maximum material discrimination with spectral CT. The wider the energy bin width is, the lower the noise level is, but the poorer the reconstructed image contrast is. Here, we introduce the contrast-to-noise ratio (CNR criterion to optimize the energy bin width after the K-edge jump for the maximum CNR. In the simulation, we analyze the reconstructed image quality in different energy bins and demonstrate that our proposed optimization approach can maximize CNR between target region and background region in reconstructed image.

  9. AN N-BODY INTEGRATOR FOR GRAVITATING PLANETARY RINGS, AND THE OUTER EDGE OF SATURN'S B RING

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, Joseph M. [Space Science Institute, c/o Center for Space Research, University of Texas at Austin, 3925 West Braker Lane, Suite 200, Austin, TX 78759-5378 (United States); Spitale, Joseph N., E-mail: jhahn@spacescience.org, E-mail: jnspitale@psi.edu [Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719-2395 (United States)

    2013-08-01

    A new symplectic N-body integrator is introduced, one designed to calculate the global 360 Degree-Sign evolution of a self-gravitating planetary ring that is in orbit about an oblate planet. This freely available code is called epi{sub i}nt, and it is distinct from other such codes in its use of streamlines to calculate the effects of ring self-gravity. The great advantage of this approach is that the perturbing forces arise from smooth wires of ring matter rather than discreet particles, so there is very little gravitational scattering and so only a modest number of particles are needed to simulate, say, the scalloped edge of a resonantly confined ring or the propagation of spiral density waves. The code is applied to the outer edge of Saturn's B ring, and a comparison of Cassini measurements of the ring's forced response to simulations of Mimas's resonant perturbations reveals that the B ring's surface density at its outer edge is {sigma}{sub 0} = 195 {+-} 60 g cm{sup -2}, which, if the same everywhere across the ring, would mean that the B ring's mass is about 90% of Mimas's mass. Cassini observations show that the B ring-edge has several free normal modes, which are long-lived disturbances of the ring-edge that are not driven by any known satellite resonances. Although the mechanism that excites or sustains these normal modes is unknown, we can plant such a disturbance at a simulated ring's edge and find that these modes persist without any damping for more than {approx}10{sup 5} orbits or {approx}100 yr despite the simulated ring's viscosity {nu}{sub s} = 100 cm{sup 2} s{sup -1}. These simulations also indicate that impulsive disturbances at a ring can excite long-lived normal modes, which suggests that an impact in the recent past by perhaps a cloud of cometary debris might have excited these disturbances, which are quite common to many of Saturn's sharp-edged rings.

  10. Competition and evolution of dielectric waveguide mode and plasmonic waveguide mode

    Science.gov (United States)

    Yuan, Sheng-Nan; Fang, Yun-Tuan

    2017-10-01

    In order to study the coupling and evolution law of the waveguide mode and two plasmonic surface modes, we construct a line defect waveguide based on hexagonal honeycomb plasmonic photonic crystal. Through adjusting the radius of the edge dielectric rods, the competition and evolution behaviors occur between dielectric waveguide mode and plasmonic waveguide mode. There are three status: only plasmonic waveguide modes occur for rA 0.25a; two kinds of modes coexist for 0.09a slow light.

  11. Study regarding the density evolution of messages and the characteristic functions associated of a LDPC code

    Science.gov (United States)

    Drăghici, S.; Proştean, O.; Răduca, E.; Haţiegan, C.; Hălălae, I.; Pădureanu, I.; Nedeloni, M.; (Barboni Haţiegan, L.

    2017-01-01

    In this paper a method with which a set of characteristic functions are associated to a LDPC code is shown and also functions that represent the evolution density of messages that go along the edges of a Tanner graph. Graphic representations of the density evolution are shown respectively the study and simulation of likelihood threshold that render asymptotic boundaries between which there are decodable codes were made using MathCad V14 software.

  12. Edge anisotropy and the geometric perspective on flow networks

    Science.gov (United States)

    Molkenthin, Nora; Kutza, Hannes; Tupikina, Liubov; Marwan, Norbert; Donges, Jonathan F.; Feudel, Ulrike; Kurths, Jürgen; Donner, Reik V.

    2017-03-01

    Spatial networks have recently attracted great interest in various fields of research. While the traditional network-theoretic viewpoint is commonly restricted to their topological characteristics (often disregarding the existing spatial constraints), this work takes a geometric perspective, which considers vertices and edges as objects in a metric space and quantifies the corresponding spatial distribution and alignment. For this purpose, we introduce the concept of edge anisotropy and define a class of measures characterizing the spatial directedness of connections. Specifically, we demonstrate that the local anisotropy of edges incident to a given vertex provides useful information about the local geometry of geophysical flows based on networks constructed from spatio-temporal data, which is complementary to topological characteristics of the same flow networks. Taken both structural and geometric viewpoints together can thus assist the identification of underlying flow structures from observations of scalar variables.

  13. The vehicle routing problem with edge set costs

    DEFF Research Database (Denmark)

    Reinhardt, Line Blander; Jepsen, Mads Kehlet; Pisinger, David

    . The certifications and contributions impose a cost for the company while they also give unlimited usage of a set of roads to all vehicles belonging to the company. Different versions for defining the edge sets are discussed and formulated. A MIP-formulation of the problem is presented, and a solution method based......We consider an important generalization of the vehicle routing problem with time windows in which a fixed cost must be paid for accessing a set of edges. This fixed cost could reflect payment for toll roads, investment in new facilities, the need for certifications and other costly investments...... on branch-and-price-and-cut is applied to the problem. The computational results show that instances with up to 50 customers can be solved in reasonable time, and that the branch-cut-and-price algorithm generally outperforms CPLEX. It also seems that instances get more difficult when the penalized edge sets...

  14. Radiative distortion of kinematic edges in cascade decays

    Directory of Open Access Journals (Sweden)

    M. Beneke

    2017-07-01

    Full Text Available Kinematic edges of cascade decays of new particles produced in high-energy collisions may provide important constraints on the involved particles' masses. For the exemplary case of gluino decay g˜→qq¯χ˜ into a pair of quarks and a neutralino through a squark resonance, we study the hadronic invariant mass distribution in the vicinity of the kinematic edge. We perform a next-to-leading order calculation in the strong coupling αs and the ratio of squark width and squark mass Γq˜/mq˜, based on a systematic expansion in Γq˜/mq˜. The separation into hard, collinear and soft contributions elucidates the process-dependent and universal features of distributions in the edge region, represented by on-shell decay matrix elements, universal jet functions and a soft function that depends on the resonance propagator and soft Wilson lines.

  15. The effects of leading edge roughness on dynamic stall

    Science.gov (United States)

    Hrynuk, John

    2016-11-01

    Dynamic stall is a fundamental flow phenomenon that is commonly observed for insect flight and rotorcraft. Under certain conditions a leading edge vortex forms generating large but temporary lift forces. Historically, computations studying dynamic stall on airfoil shapes have struggled to predict this vortex formation time and separation point. Reduced order models and CFD have performed well when experiments have been performed to develop separation models, but this has limited the development of robust design tools. The current study looks at the effect of leading edge surface roughness on the formation of the Dynamic Stall Vortex (DSV). Roughness elements were applied to the leading edge of a NACA 0012 airfoil and PIV data of the vortex formation process was recorded. Measurements were taken at a Reynolds number of Re = 12,000 and baseline smooth NACA 0012 data was also recorded for comparison. Surface roughness elements, below the typical scale modeled by CFD, are shown to change DSV formation angle and location.

  16. A dynamic stall model for airfoils with deformable trailing edges

    DEFF Research Database (Denmark)

    Andersen, Peter Bjørn; Gaunaa, Mac; Bak, Christian

    2009-01-01

    , lead-lag, pitch, trailing-edge flapping. In the linear region, the model reduces to the inviscid model, which includes the aerodynamic effect of a thin airfoil with a deformable camberline in inviscid flow. Therefore, the proposed model can be considered a crossover between the work of Gaunaa......The present work contains an extension of the Beddoes-Leishman-type dynamic stall model. In this work, a deformable trailing-edge flap has been added to the dynamic stall model. The model predicts the unsteady aerodynamic forces and moments on an airfoil section undergoing arbitrary motion in heave...... for the attached flow region and Hansen et al. The model is compared qualitatively to wind tunnel measurements of a Riso/ B1-18 blade section equipped with deformable trailing-edge flap devices in the form of piezoelectric devices. Copyright © 2009 John Wiley & Sons, Ltd....

  17. Heterospin Junctions in Zigzag-Edged Graphene Nanoribbons

    Directory of Open Access Journals (Sweden)

    Eduardo C. Girão

    2014-08-01

    Full Text Available We propose a graphene nanoribbon-based heterojunction, where a defect-free interface separates two zigzag graphene nanoribbons prepared in opposite antiferromagnetic spin configurations. This heterospin junction is found to allow the redirecting of low-energy electrons from one edge to the other. The basic scattering mechanisms and their relation to the system’s geometry are investigated through a combination of Landauer–Green’s function and the S-matrix and eigen-channel methods within a tight-binding + Hubbard model validated with density functional theory. The findings demonstrate the possibility of using zigzag-edged graphene nanoribbons (zGNRs in complex networks where current can be transmitted across the entire system, instead of following the shortest paths along connected edges belonging to the same sub-lattice.

  18. Canny Edge Detection in Cross-Spectral Fused Images

    Directory of Open Access Journals (Sweden)

    Patricia Suárez

    2017-02-01

    Full Text Available Considering that the images of different spectra provide an ample information that helps a lo in the process of identification and distinction of objects that have unique spectral signatures. In this paper, the use of cross-spectral images in the process of edge detection is evaluated. This study aims to assess the Canny edge detector with two variants. The first relates to the use of merged cross-spectral images and the second the inclusion of morphological filters. To ensure the quality of the data used in this study the GQM (Goal-Question- Metrics, framework, was applied to reduce noise and increase the entropy on images. The metrics obtained in the experiments confirm that the quantity and quality of the detected edges increases significantly after the inclusion of a morphological filter and a channel of near infrared spectrum in the merged images.

  19. Highly edge-connected detachments of graphs and digraphs

    DEFF Research Database (Denmark)

    Berg, Alex Rune; Jackson, Bill; Jordan, Tibor

    2003-01-01

    Let G=(V,E) be a graph or digraph and r:V \\to Z+. An r-detachment of G is a graph H obtained by `splitting' each vertex v \\in V into r(v) vertices. The vertices v1,...,vr(v) obtained by splitting v are called the pieces of v in H. Every edge uv \\in E corresponds to an edge of H connecting some...... piece of u to some piece of v. Crispin Nash-Williams gave necessary and sufficient conditions for a graph to have a k-edge-connected r-detachment. He also solved the version where the degrees of all the pieces are specified. In this paper we solve the same problems for directed graphs. We also give...

  20. Using quantum filters as edge detectors in infrared images

    Science.gov (United States)

    Bolaños Marín, Daniela

    2014-06-01

    Some new filters inspired in quantum models are used as edge detectors in infrared images. In this case, Bessel, Hermite and Morse filters will be applied to detect edges and fibrillar structures in infrared images. The edge detectors will be built by the Laplacian of the mentioned quantum filters. Furthermore, using curvature operators, curvature detectors and amplifiers of contrast will be constructed to analyze infrared images. The quantum filter prototyping will be done using computer algebra software, specifically Maple and its package, ImageTools. The quantum filters will be applied to infrared images using the technique of convolutions and blurred derivatives. It is expected that designed quantum filters will be useful for analysis and processing of infrared images. As future investigations, we propose to design plugins with the quantum filters that can be incorporated into the program ImageJ, which will facilitate the use of the quantum filters for the infrared image processing.

  1. On the Edge-Hyper-Hamiltonian Laceability of Balanced Hypercubes

    Directory of Open Access Journals (Sweden)

    Cao Jianxiang

    2016-11-01

    Full Text Available The balanced hypercube BHn, defined by Wu and Huang, is a variant of the hypercube network Qn, and has been proved to have better properties than Qn with the same number of links and processors. For a bipartite graph G = (V0 ∪ V1,E, we say G is edge-hyper-Hamiltonian laceable if it is Hamiltonian laceable, and for any vertex v ∈ Vi, i ∈ {0, 1}, any edge e ∈ E(G − v, there is a Hamiltonian path containing e in G − v between any two vertices of V1−i. In this paper, we prove that BHn is edge-hy per- Hamiltonian laceable.

  2. Edge nonlinear optics on a MoS₂ atomic monolayer.

    Science.gov (United States)

    Yin, Xiaobo; Ye, Ziliang; Chenet, Daniel A; Ye, Yu; O'Brien, Kevin; Hone, James C; Zhang, Xiang

    2014-05-02

    The translational symmetry breaking of a crystal at its surface may form two-dimensional (2D) electronic states. We observed one-dimensional nonlinear optical edge states of a single atomic membrane of molybdenum disulfide (MoS2), a transition metal dichalcogenide. The electronic structure changes at the edges of the 2D crystal result in strong resonant nonlinear optical susceptibilities, allowing direct optical imaging of the atomic edges and boundaries of a 2D material. Using the symmetry of the nonlinear optical responses, we developed a nonlinear optical imaging technique that allows rapid and all-optical determination of the crystal orientations of the 2D material at a large scale. Our technique provides a route toward understanding and making use of the emerging 2D materials and devices.

  3. A new edge detection algorithm based on Canny idea

    Science.gov (United States)

    Feng, Yingke; Zhang, Jinmin; Wang, Siming

    2017-10-01

    The traditional Canny algorithm has poor self-adaptability threshold, and it is more sensitive to noise. In order to overcome these drawbacks, this paper proposed a new edge detection method based on Canny algorithm. Firstly, the media filtering and filtering based on the method of Euclidean distance are adopted to process it; secondly using the Frei-chen algorithm to calculate gradient amplitude; finally, using the Otsu algorithm to calculate partial gradient amplitude operation to get images of thresholds value, then find the average of all thresholds that had been calculated, half of the average is high threshold value, and the half of the high threshold value is low threshold value. Experiment results show that this new method can effectively suppress noise disturbance, keep the edge information, and also improve the edge detection accuracy.

  4. Failures in Trailing Edge Bondlines of Wind Turbine Blades

    DEFF Research Database (Denmark)

    Jensen, F. M.; Sørensen, John Dalsgaard; Nielsen, P. H.

    2011-01-01

    Bonded joints in composite structures are often en object for concern. This is also true for wind turbine blades, where damage occurs in the trailing edge due to fatigue loads. Reliability of wind turbines becomes increasingly important when used offshore, where operation and maintenance costs...... constitute a significant part of the cost per kWh produced. However, the wind turbine industy is reluctant to share statistical values for damages, and this makes it more difficult to assess the reliability. Instead of analyzing the joint and reinforce the connection, research at Risø DTU has shown......, that it possible to reduce the deformation of the trailing edge panels and thereby reduce the peeling stresses in the trailing edge joint. A basic solution patented by Risø DTU is presented. The research is based on a combination of numerical analysis and full-scale testing. The research has shown the need...

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

    Science.gov (United States)

    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.

  6. Detecting Character Dependencies in Stochastic Models of Evolution.

    Science.gov (United States)

    Chakrabarty, Deeparnab; Kannan, Sampath; Tian, Kevin

    2016-03-01

    Stochastic models of biological evolution generally assume that different characters (runs of the stochastic process) are independent and identically distributed. In this article we determine the asymptotic complexity of detecting dependence for some fairly general models of evolution, but simple models of dependence. A key difference from much of the previous work is that our algorithms work without knowledge of the tree topology. Specifically, we consider various stochastic models of evolution ranging from the common ones used by biologists (such as Cavender-Farris-Neyman and Jukes-Cantor models) to very general ones where evolution of different characters can be governed by different transition matrices on each edge of the evolutionary tree (phylogeny). We also consider several models of dependence between two characters. In the most specific model, on each edge of the phylogeny the joint distribution of the dependent characters undergoes a perturbation of a fixed magnitude, in a fixed direction from what it would be if the characters were evolving independently. More general dependence models don't require such a strong "signal." Instead they only require that on each edge, the perturbation of the joint distribution has a significant component in a specific direction. Our main results are nearly tight bounds on the induced or operator norm of the transition matrices that would allow us to detect dependence efficiently for most models of evolution and dependence that we consider. We make essential use of a new concentration result for multistate random variables of a Markov random field on arbitrary trivalent trees: We show that the random variable counting the number of leaves in any particular state has variance that is subquadratic in the number of leaves.

  7. Understanding the edge crack phenomenon in ceramic laminates

    Directory of Open Access Journals (Sweden)

    O. Ševeček

    2015-10-01

    Full Text Available Layered ceramic materials (also referred to as “ceramic laminates” are becoming one of the most promising areas of materials technology aiming to improve the brittle behavior of bulk ceramics. The utilization of tailored compressive residual stresses acting as physical barriers to crack propagation has already succeeded in many ceramic systems. Relatively thick compressive layers located below the surface have proven very effective to enhance the fracture resistance and provide a minimum strength for the material. However, internal compressive stresses result in out-of plane stresses at the free surfaces, what can cause cracking of the compressive layer, forming the so-called edge cracks. Experimental observations have shown that edge cracking may be associated with the magnitude of the compressive stresses and with the thickness of the compressive layer. However, an understanding of the parameters related to the onset and extension of such edge cracks in the compressive layers is still lacking. In this work, a 2D parametric finite element model has been developed to predict the onset and propagation of an edge crack in ceramic laminates using a coupled stress-energy criterion. This approach states that a crack is originated when both stress and energy criteria are fulfilled simultaneously. Several designs with different residual stresses and a given thickness in the compressive layers have been computed. The results predict the existence of a lower bound, below no edge crack will be observed, and an upper bound, beyond which the onset of an edge crack would lead to the complete fracture of the layer

  8. Progress in the Development of Edge Scatter Control for Starshades

    Science.gov (United States)

    Casement, L. Suzanne; Warwick, Steve; Smith, Daniel

    2016-01-01

    In the field of ExoPlanet detection and characterization, the use of a Starshade, an external occulter in front of a telescope at large separations, has been identified as one of the highly promising methods to achieve the goals. In the last major review (Lawson, JPL D-72279, 2013), the control of scattered sunlight from the edges of the starshade into the telescope was identified as one of the key technology development areas in order to make the starshade feasible. Modeling of the scattered light has resulted in very different results (Casement et al., SPIE Vol. 8442, 4H, 2012, Martin et al., SPIE Vol. 8864, 88641A, 2013) so a campaign of experimentation with edge samples was undertaken to attempt to resolve the discrepancies.Here, we present our latest results from both modeling efforts and measurement of samples of materials which would be suitable for manufacturing the starshade edge. We have focused on coating metallic samples for ease of fabrication, including measuring the sharpness of an edge that can be fabricated using standard machine shop methods of a variety of materials that are suitable for space application. We then had these samples coated by two suppliers to evaluate how well these coating types would conform to the edge and provide scatter suppression. The results of scatter measurements of these coated edge samples are presented. In addition, we have subjected these samples to a limited set of environments to evaluate their durability and followed up by remeasuring a portion of these exposed samples to compare the scatter suppression before and after environmental exposure.

  9. Aerodynamic noise from rigid trailing edges with finite porous extensions

    Science.gov (United States)

    Kisil, A.; Ayton, L. J.

    2018-02-01

    This paper investigates the effects of finite flat porous extensions to semi-infinite impermeable flat plates in an attempt to control trailing-edge noise through bio-inspired adaptations. Specifically the problem of sound generated by a gust convecting in uniform mean steady flow scattering off the trailing edge and permeable-impermeable junction is considered. This setup supposes that any realistic trailing-edge adaptation to a blade would be sufficiently small so that the turbulent boundary layer encapsulates both the porous edge and the permeable-impermeable junction, and therefore the interaction of acoustics generated at these two discontinuous boundaries is important. The acoustic problem is tackled analytically through use of the Wiener-Hopf method. A two-dimensional matrix Wiener-Hopf problem arises due to the two interaction points (the trailing edge and the permeable-impermeable junction). This paper discusses a new iterative method for solving this matrix Wiener-Hopf equation which extends to further two-dimensional problems in particular those involving analytic terms that exponentially grow in the upper or lower half planes. This method is an extension of the commonly used "pole removal" technique and avoids the needs for full matrix factorisation. Convergence of this iterative method to an exact solution is shown to be particularly fast when terms neglected in the second step are formally smaller than all other terms retained. The final acoustic solution highlights the effects of the permeable-impermeable junction on the generated noise, in particular how this junction affects the far-field noise generated by high-frequency gusts by creating an interference to typical trailing-edge scattering. This effect results in partially porous plates predicting a lower noise reduction than fully porous plates when compared to fully impermeable plates.

  10. Dynamical phenomena at the inner edge of the Keeler gap

    Science.gov (United States)

    Tajeddine, Radwan; Nicholson, Philip D.; Tiscareno, Matthew S.; Hedman, Matthew M.; Burns, Joseph A.; El Moutamid, Maryame

    2017-06-01

    We analyze several thousand Cassini ISS images in order to study the inner edge of the Keeler gap in Saturn's outer A ring. We find strong evidence for an m = 32 perturbation with a mean amplitude of radial variation of 4.5 km. Phase analysis yields a pattern speed consistent with the mean motion of Prometheus, indicating that this pattern is generated by the 32:31 Inner Lindblad resonance with Prometheus. In addition, we find evidence of 18-lobed and 20-lobed patterns with amplitudes of ∼1.5 km. These patterns, whose rotation rates correspond to resonance locations ∼4 km interior to the gap edge, are believed to be normal modes. The former is probably related to the nearby 18:17 (m = 18) resonance with Pandora. In addition to these resonant and normal mode patterns, we also observe multiple localized features that appear to move at the local keplerian rate and that persist for only a few months. One hypothesis is that different groups of ring particles at the inner edge of the gap may be reacting differently to the resonance with Prometheus, with local variations in the forced eccentricity and/or pericenter; an alternative hypothesis is the existence of several unseen objects embedded at or near the inner edge of the Keeler gap, similar to those suspected to exist at the outer edges of the A and B rings. In either case, observations of the ring edge at opposite ansae demonstrate that the localized features must be on eccentric orbits.

  11. Edge-based compression of cartoon-like images with homogeneous diffusion

    DEFF Research Database (Denmark)

    Mainberger, Markus; Bruhn, Andrés; Weickert, Joachim

    2011-01-01

    Edges provide semantically important image features. In this paper a lossy compression method for cartoon-like images is presented, which is based on edge information. Edges together with some adjacent grey/colour values are extracted and encoded using a classical edge detector, binary compressio...

  12. Color Degree Sum Conditions for Rainbow Triangles in Edge-Colored Graphs

    NARCIS (Netherlands)

    Li, Ruonan; Ning, Bo; Zhang, Shenggui

    Let G be an edge-colored graph and v a vertex of G. The color degree of v is the number of colors appearing on the edges incident to v. A rainbow triangle in G is one in which all edges have distinct colors. In this paper, we first prove that an edge-colored graph on n vertices contains a rainbow

  13. Simulation Analysis of Zero Mean Flow Edge Turbulence in LAPD

    Science.gov (United States)

    Friedman, Brett Cory

    I model, simulate, and analyze the turbulence in a particular experiment on the Large Plasma Device (LAPD) at UCLA. The experiment, conducted by Schaffner et al. [D. Schaffner et al., Phys. Rev. Lett. 109, 135002 (2012)], nulls out the intrinsic mean flow in LAPD by limiter biasing. The model that I use in the simulation is an electrostatic reduced Braginskii two-fluid model that describes the time evolution of density, electron temperature, electrostatic potential, and parallel electron velocity fluctuations in the edge region of LAPD. The spatial domain is annular, encompassing the radial coordinates over which a significant equilibrium density gradient exists. My model breaks the independent variables in the equations into time-independent equilibrium parts and time-dependent fluctuating parts, and I use experimentally obtained values as input for the equilibrium parts. After an initial exponential growth period due to a linear drift wave instability, the fluctuations saturate and the frequency and azimuthal wavenumber spectra become broadband with no visible coherent peaks, at which point the fluctuations become turbulent. The turbulence develops intermittent pressure and flow filamentary structures that grow and dissipate, but look much different than the unstable linear drift waves, primarily in the extremely long axial wavelengths that the filaments possess. An energy dynamics analysis that I derive reveals the mechanism that drives these structures. The long k|| ˜ 0 intermittent potential filaments convect equilibrium density across the equilibrium density gradient, setting up local density filaments. These density filaments, also with k || ˜ 0, produce azimuthal density gradients, which drive radially propagating secondary drift waves. These finite k|| drift waves nonlinearly couple to one another and reinforce the original convective filament, allowing the process to bootstrap itself. The growth of these structures is by nonlinear instability because

  14. Improvement of airfoil trailing edge bluntness noise model

    DEFF Research Database (Denmark)

    Zhu, Wei Jun; Shen, Wen Zhong; Sørensen, Jens Nørkær

    2016-01-01

    In this article, airfoil trailing edge bluntness noise is investigated using both computational aero-acoustic and semi-empirical approach. For engineering purposes, one of the most commonly used prediction tools for trailing edge noise are based on semi-empirical approaches, for example, the Brooks......, Pope, and Marcolini airfoil noise prediction model developed by Brooks, Pope, and Marcolini (NASA Reference Publication 1218, 1989). It was found in previous study that the Brooks, Pope, and Marcolini model tends to over-predict noise at high frequencies. Furthermore, it was observed...

  15. A dynamic stall model for airfoils with deformable trailing edges

    DEFF Research Database (Denmark)

    Andersen, Peter Bjørn; Gaunaa, Mac; Bak, Dan Christian

    2007-01-01

    on an airfoil section undergoing arbitrary motion in heave, lead-lag, pitch, Trailing Edge (TE) flapping. In the linear region, the model reduces to the inviscid model of Gaunaa [4], which includes the aerodynamic effect of a thin airfoil with a deformable camberline in inviscid flow. Therefore, the proposed......The present work contains an extension of the Beddoes-Leishman (B-L) type dynamic stall model, as described by Hansen et al. [7]. In this work a Deformable Trailing Edge Geometry (DTEG) has been added to the dynamic stall model. The model predicts the unsteady aerodynamic forces and moments...

  16. Electronic transport across metal-graphene edge contact

    Science.gov (United States)

    Gong, Cheng; Zhang, Chenxi; Oh, Young Jun; Wang, Weichao; Lee, Geunsik; Shan, Bin; Wallace, Robert M.; Cho, Kyeongjae

    2017-06-01

    The electronic transport across metal-graphene edge-contact structures is studied by first principles methods. Unusual double-dip transmission as a function of Fermi level is found for a Pd electrode over varying grapheme lengths. Interface metal-carbon hybridization is shown to introduce random distribution of π-orbital local density of states at different carbon sites leading to transmission suppression. For a Ti electrode, two dips are merged into one with a ~0.2 eV transport gap opening. Our work sheds light on the origin of intrinsic contact resistance at metal-graphene edge contact.

  17. Sudden distortion of turbulence at a forest edge

    DEFF Research Database (Denmark)

    Mann, Jakob; Dellwik, Ebba

    2014-01-01

    Dellwik et al. (2013) presented data from a forest edge experiment based on two meteorological towers instrumented with sonic anemometers. The experiment was performed at a dense edge of the Tromnæs Forest, which is a 24 m tall mature beech stand on the island Falster, Denmark. The topography at ...... with the turbulence model by Mann (1994), and investigate whether this model can predict the observed changes of the flow. The presented results are relevant for understanding the rapid changes of turbulence in the heterogeneous landscape....

  18. Flexible edge seal for vacuum insulating glazing units

    Science.gov (United States)

    Bettger, Kenneth J.; Stark, David H.

    2012-12-11

    A flexible edge seal is provided for a vacuum insulating glazing unit having a first glass pane and a second glass pane spaced-apart from the first. The edge seal comprises a seal member formed of a hermetically bondable material and having a first end, a second end and a center section disposed therebetween. The first end is hermetically bondable to a first glass pane. The second end is hermetically bondable to a second glass pane. The center section comprises a plurality of convolutes.

  19. Trailing edge noise model applied to wind turbine airfoils

    Energy Technology Data Exchange (ETDEWEB)

    Bertagnolio, F.

    2008-01-15

    The aim of this work is firstly to provide a quick introduction to the theory of noise generation that are relevant to wind turbine technology with focus on trailing edge noise. Secondly, the socalled TNO trailing edge noise model developed by Parchen [1] is described in more details. The model is tested and validated by comparing with other results from the literature. Finally, this model is used in the optimization process of two reference airfoils in order to reduce their noise signature: the RISOE-B1-18 and the S809 airfoils. (au)

  20. High power singlemode edge-emitting master oscillator power amplifier

    Science.gov (United States)

    O'Brien, S.; Parke, R.; Welch, D. F.; Mehuys, D.; Scifres, D.

    1992-01-01

    An edge-emitting monolithically integrated master oscillator power amplifier (M-MOPA) has been fabricated by integrating a distributed Bragg reflector laser with a 500 microns long single mode amplifier. The M-MOPA contains a strained InGaAs quantum well in the active region and operates at about 981.5 nm in an edge-emitting fashion with maximum powers in excess of 175 mW. Single longitudinal and transverse mode operation is maintained to powers in excess of 110 mW CW.

  1. Highly Edge-Connected Detachments of Graphs and Digraphs

    DEFF Research Database (Denmark)

    Berg, Alex Rune; Jackson, Bill; Jordán, Tibor

    2003-01-01

    Let G = (V,E) be a graph or digraph and r : V → Z+. An r-detachment of G is a graph H obtained by ‘splitting’ each vertex ν ∈ V into r(ν) vertices. The vertices ν1,…,νr(ν) obtained by splitting ν are called the pieces of ν in H. Every edge uν ∈ E corresponds to an edge of H connecting some piece ...... a simple and self-contained new proof for the undirected result. This work is dedicated to the memory of Crispin Nash-Williams....

  2. Quantum pump in quantum spin Hall edge states

    Science.gov (United States)

    Cheng, Fang

    2016-09-01

    We present a theory for quantum pump in a quantum spin Hall bar with two quantum point contacts (QPCs). The pump currents can be generated by applying harmonically modulating gate voltages at QPCs. The phase difference between the gate voltages introduces an effective gauge field, which breaks the time-reversal symmetry and generates pump currents. The pump currents display very different pump frequency dependence for weak and strong e-e interaction. These unique properties are induced by the helical feature of the edge states, and therefore can be used to detect and control edge state transport.

  3. Ultrasonic System Approach to Obstacle Detection and Edge Detection

    Directory of Open Access Journals (Sweden)

    Yin Thu Win

    2011-04-01

    Full Text Available In this paper, ultrasonic system approach to obstacle detection and edge detection for industrial and rescue operations has been presented. The developed system consists of tough sonic sensor configure with personal computer for monitoring. First, the mathematical model has been presented for the object detection system. Then the numerical simulation has been performed using Matlab platform. The experiments have been conducted using ultrasonic frequency. The curtain, paper and bamboo sheet have been considered as a media during experiments. The presented system is highly accurate for object detection and edge detection behind the obstacle.

  4. Automated edge finishing using an active XY table

    Science.gov (United States)

    Loucks, Clifford S.; Starr, Gregory P.

    1993-01-01

    The disclosure is directed to an apparatus and method for automated edge finishing using hybrid position/force control of an XY table. The disclosure is particularly directed to learning the trajectory of the edge of a workpiece by "guarded moves". Machining is done by controllably moving the XY table, with the workpiece mounted thereon, along the learned trajectory with feedback from a force sensor. Other similar workpieces can be mounted, without a fixture on the XY table, located and the learned trajectory adjusted

  5. Anderson Localization of Ultracold Atoms: Where is the Mobility Edge?

    Science.gov (United States)

    Pasek, Michael; Orso, Giuliano; Delande, Dominique

    2017-04-01

    Recent experiments in noninteracting ultracold atoms in three-dimensional speckle potentials have yielded conflicting results regarding the so-called mobility edge, i.e., the energy threshold separating Anderson localized from diffusive states. At the same time, there are theoretical indications that most experimental data overestimate this critical energy, sometimes by a large amount. Using extensive numerical simulations, we show that the effect of anisotropy in the spatial correlations of realistic disorder configurations alone is not sufficient to explain the experimental data. In particular, we find that the mobility edge obeys a universal scaling behavior, independently of the speckle geometry.

  6. Phase Contrast Imaging Measurements of Edge Turbulence Across an H-mode Transition

    Science.gov (United States)

    Rost, J. C.; Marinoni, A.; Porkolab, M.; Burrell, K. H.

    2013-10-01

    The Phase Contrast Imaging (PCI) diagnostic on DIII-D provides a line-integrated measurement of density fluctuations. Analysis of previous PCI data taken during QH mode plasmas has revealed turbulence with short radial wavelengths and high frequencies which is generated by the well in the radial electric field Er. Application of these results allows us to study the rapid evolution in turbulence at an L-H transition. The dominant effect of the L-H transition on turbulence is a 70% drop in fluctuation amplitude. However high frequency fluctuations are seen to arise on the same time scale as the L-H transition (i.e. a few ms). Interpretation of the 2d spectrum S (k , f) of the PCI data of the line-integrated fluctuation, especially the Doppler shift and the ratio S (kpci / S (-kpci) , indicates that the high frequency fluctuations are located on the inner edge of the Er well. There is in addition a region of turbulence the PCI detects which is located outside the minimum of the Er well. This ongoing work will provide quantitative information on the evolution of the Er well at high time resolution across the L-H transition, important to understanding the interaction between turbulence and flow shear at the H-mode transition. Work supported by the US Department of Energy under DE-FG02-94ER54235 and DE-FC02-04ER54698.

  7. Magnetic edge states in MoS2 characterized using density-functional theory

    DEFF Research Database (Denmark)

    Vojvodic, Aleksandra; Hinnemann, B.; Nørskov, Jens Kehlet

    2009-01-01

    It is known that the edges of a two-dimensional slab of insulating MoS2 exhibit one-dimensional metallic edge states, the so-called "brim states." Here, we find from density-functional theory calculations that several edge structures, which are relevant for the hydrodesulfurization process......, are magnetic. The magnetism is an edge phenomenon associated with certain metallic edge states. Interestingly, we find that among the two low-index edges, only the S edge displays magnetism under hydrodesulfurization conditions. In addition, the implications of this on the catalytic activity are investigated...

  8. Evolution of the Freshwater Eels

    Science.gov (United States)

    Aoyama, Jun; Tsukamoto, Katsumi

    The freshwater anguillid eels have an unusual life history and world-wide distribution. Questions about the phylogenetic relationships of this group and how their long spawning migrations and larval phase may contribute to their global distribution have not been addressed. This paper is first presentation of molecular phylogeny of Anguilla species, and based on this phylogenetic tree we suggest new aspect of the evolution of this group. Namely, ancestral eels originated during the Eocene or earlier, in the western Pacific Ocean near present-day Indonesia. A group derived from this ancestor dispersed westward, probably by larval transport in the global circum-equatorial current through the northern edge of the Tethys Sea. This group split into the ancestor of the European and American eels, which entered into the Atlantic Ocean, and a second group, which dispersed southward and split into the east African species and Australian species. Thus the world-wide distribution of the eel family can be understood from knowledge of continental drift, ocean currents, a specialized larva and evolutionary forces favoring dispersal and speciation of segregated gene pool.

  9. [An improved morphological edge detection algorithm of medical image based on multi-structure element].

    Science.gov (United States)

    Luo, Xiaogang; Liu, Ting; Peng, Chenglin; Wen, Li

    2009-02-01

    An improved edge detection algorithm is proposed in this paper for the medical images with strong noises and fuzzy edges. The algorithm modified the combination of morphological operations, so that the unclear edges of the images are avoided. In this paper is also introduced the algorithm of multi-structure elements which can reserve integrated edges from different directions of the images. Furthermore, the contrast enhancement and morphological filter processing are implemented. This method can detect the edges efficiently, keep the detected edges smooth and obtain coherent image edges. Experiments demonstrate that this edge detector has a better performance of noise reduction and keeps the edges more accurate than do the traditional edge detectors; thus its practicality is enhanced.

  10. Edges in CNC polishing: from mirror-segments towards semiconductors, paper 1: edges on processing the global surface.

    Science.gov (United States)

    Walker, David; Yu, Guoyu; Li, Hongyu; Messelink, Wilhelmus; Evans, Rob; Beaucamp, Anthony

    2012-08-27

    Segment-edges for extremely large telescopes are critical for observations requiring high contrast and SNR, e.g. detecting exo-planets. In parallel, industrial requirements for edge-control are emerging in several applications. This paper reports on a new approach, where edges are controlled throughout polishing of the entire surface of a part, which has been pre-machined to its final external dimensions. The method deploys compliant bonnets delivering influence functions of variable diameter, complemented by small pitch tools sized to accommodate aspheric mis-fit. We describe results on witness hexagons in preparation for full size prototype segments for the European Extremely Large Telescope, and comment on wider applications of the technology.

  11. Effects of suture position on left ventricular fluid mechanics under mitral valve edge-to-edge repair.

    Science.gov (United States)

    Du, Dongxing; Jiang, Song; Wang, Ze; Hu, Yingying; He, Zhaoming

    2014-01-01

    Mitral valve (MV) edge-to-edge repair (ETER) is a surgical procedure for the correction of mitral valve regurgitation by suturing the free edge of the leaflets. The leaflets are often sutured at three different positions: central, lateral and commissural portions. To study the effects of position of suture on left ventricular (LV) fluid mechanics under mitral valve ETER, a parametric model of MV-LV system during diastole was developed. The distribution and development of vortex and atrio-ventricular pressure under different suture position were investigated. Results show that the MV sutured at central and lateral in ETER creates two vortex rings around two jets, compared with single vortex ring around one jet of the MV sutured at commissure. Smaller total orifices lead to a higher pressure difference across the atrio-ventricular leaflets in diastole. The central suture generates smaller wall shear stresses than the lateral suture, while the commissural suture generated the minimum wall shear stresses in ETER.

  12. Robust Anisotropic Diffusion Based Edge Enhancement for Level Set Segmentation and Asymmetry Analysis of Breast Thermograms using Zernike Moments.

    Science.gov (United States)

    Prabha, S; Sujatha, C M; Ramakrishnan, S

    2015-01-01

    Breast thermography plays a major role in early detection of breast cancer in which the thermal variations are associated with precancerous state of breast. The distribution of asymmetrical thermal patterns indicates the pathological condition in breast thermal images. In this work, asymmetry analysis of breast thermal images is carried out using level set segmentation and Zernike moments. The breast tissues are subjected to Tukey’s biweight robust anisotropic diffusion filtering (TBRAD) for the generation of edge map. Reaction diffusion level set method is employed for segmentation in which TBRAD edge map is used as stopping criterion during the level set evolution. Zernike moments are extracted from the segmented breast tissues to perform asymmetry analysis. Results show that the TBRAD filter is able to enhance the edges near infra mammary folds and lower breast boundaries effectively. It is observed that segmented breast tissues are found to be continuous and has sharper boundary. This method yields high degree of correlation (98%) between the segmented output and the ground truth images. Among the extracted Zernike features, higher order moments are found to be significant in demarcating normal and carcinoma breast tissues by 9%. It appears that, the methodology adopted here is useful in accurate segmentation and differentiation of normal and carcinoma breast tissues for automated diagnosis of breast abnormalities.

  13. Resonant soft X-ray reflectivity of ultrathin polymer films at the C-edge: A direct approach

    Directory of Open Access Journals (Sweden)

    Alain Gibaud

    2016-09-01

    Full Text Available The use of resonant soft X-ray reflectivity (RSXRR in s-polarization is presented with the aim to show how far it is possible to go in the understanding the evolution of the refractive index n(E=1−δ(E−iβ(E of a ultrathin polystyrene film when the RSXRR is measured through the C-edge. We evidence that a direct fit to the data provides a very good estimation of δ(E and β(E in a large range of energies. Nevertheless, at some specific energy close to C-edge we observe that it is not possible to obtain a satisfactory fit to the data though the same formalism is applied to calculate the reflectivity. We show that even though we take into account the energy resolution of the incident beam, we still end up with a poor fit at these energies. Incorporating the strong contribution of 2nd order photons appeared near C-edge we could not eliminate the discrepancy. Probably the data normalisations have some impacts on such discrepancies at some specific energies.

  14. Has Human Evolution Stopped?

    Directory of Open Access Journals (Sweden)

    Alan R. Templeton

    2010-07-01

    Full Text Available It has been argued that human evolution has stopped because humans now adapt to their environment via cultural evolution and not biological evolution. However, all organisms adapt to their environment, and humans are no exception. Culture defines much of the human environment, so cultural evolution has actually led to adaptive evolution in humans. Examples are given to illustrate the rapid pace of adaptive evolution in response to cultural innovations. These adaptive responses have important implications for infectious diseases, Mendelian genetic diseases, and systemic diseases in current human populations. Moreover, evolution proceeds by mechanisms other than natural selection. The recent growth in human population size has greatly increased the reservoir of mutational variants in the human gene pool, thereby enhancing the potential for human evolution. The increase in human population size coupled with our increased capacity to move across the globe has induced a rapid and ongoing evolutionary shift in how genetic variation is distributed within and among local human populations. In particular, genetic differences between human populations are rapidly diminishing and individual heterozygosity is increasing, with beneficial health effects. Finally, even when cultural evolution eliminates selection on a trait, the trait can still evolve due to natural selection on other traits. Our traits are not isolated, independent units, but rather are integrated into a functional whole, so selection on one trait can cause evolution to occur on another trait, sometimes with mildly maladaptive consequences.

  15. Visible-light-induced hydrogen evolution reaction with WSxSe2−x

    Indian Academy of Sciences (India)

    planes are catalytically active due to the low Gibbs free energy for hydrogen evolution reaction (HER) [11,12]. Var- ious strategies have been employed to improve the HER either by creating much active edge sites [13–17] or by chemical modification .... after 3 h, suggesting that it will not be an optimal choice as a long-term ...

  16. The Straight Edge Movement: It's Not What You Think.

    Science.gov (United States)

    Ralston, Kibby

    2000-01-01

    A high school senior describes the straight edge movement, a misunderstood youth-oriented group whose members are against smoking, drinking, doing drugs, and engaging in promiscuous sex. Straight edgers are often mislabeled as troublemakers because of their style of dress and taste in hardcore and punk music, and because of the violent actions of…

  17. Quantum capacitance of the armchair-edge graphene nanoribbon

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 81; Issue 2. Quantum capacitance of the ... Abstract. The quantum capacitance, an important parameter in the design of nanoscale devices, is derived for armchair-edge single-layer graphene nanoribbon with semiconducting property. The quantum capacitance ...

  18. Towards a novel design method for impact on leading edges

    NARCIS (Netherlands)

    van Houten, M.H.; Kaplan, H.

    2006-01-01

    Results of a parametric study concerning low velocity impact on leading edge profiles is presented. This work is the first part of a larger program on the development of an engineering design method for impact on Glare. In this first part, experimental tests and numerical simulations on

  19. Effects of edge roughness on optical scattering from periodic microstructures

    Science.gov (United States)

    Bergner, Brent C.

    Planar photonic crystals and other microstructured surfaces have important applications in a number of emerging technologies. However, these structures can be difficult to fabricate in a consistent manner. Rapid, precise measurements of critical parameters are needed to control the fabrication process, but current measurement techniques tend to be slow and often require that the sample be modified in order to make the measurement. Optical scattering can provide a rapid, non-destructive, and precise method for measuring these structures, and optical scatterometry is a good candidate technique for measuring micro-structured surfaces for process control. However, variations in the profile, such as those caused by edge roughness, can make significant contributions to the uncertainty in scatterometry measurements. Because of the multidimensional nature of the problem, modeling these variations can be computationally expensive. This dissertation examines the effects of edge roughness on optical scatterometry signals. Rigorous numerical simulations show that the effects of edge roughness are sensitive to the correlation length and the frequency content of the roughness as well as its amplitude. However, these rigorous calculations are computationally expensive. A less computationally expensive model based on a generalized Bruggeman effective medium approximation is developed and shown to be effective for modeling the effects of short correlation length edge roughness on optical scatterometry signals.

  20. On the size of edge chromatic 5-critical graphs

    Directory of Open Access Journals (Sweden)

    K. Kayathri

    2017-04-01

    Full Text Available In this paper, we study the size of edge chromatic 5-critical graphs in several classes of 5-critical graphs. In most of the classes of 5-critical graphs in this paper, we have obtained their exact size and in the other classes of 5-critical graphs, we give new bounds on their number of major vertices and size.

  1. Late movement of basin-edge lobate scarps on Mercury

    Science.gov (United States)

    Fegan, E. R.; Rothery, D. A.; Marchi, S.; Massironi, M.; Conway, S. J.; Anand, M.

    2017-05-01

    Basin-edge lobate scarps are a sub-type of tectonic shortening structure on the surface of Mercury that have formed at the edge of volcanic units that fill or partly fill impact basins. We have performed a global survey of these features and find that they are widespread in basins across the planet. We obtained model ages from crater size-frequency distribution analysis for a subset of our surveyed basins, for both the smooth plains infill and for the last resolvable tectonic activity on the associated basin-edge scarps. Our results indicate that some of these lobate scarps were still accumulating strain in the late Mansurian (approximately 1 Ga). From a photogeological assessment, we find that the orientations of these basin-edge lobate scarps are similar to those reported for the global population of lobate scarps in earlier studies, appearing to align ∼north-south at low latitudes and ∼east-west at higher latitudes. However, reassessing these landforms' orientation with artificially illuminated topographic data does not allow us to rule out the effect of illumination bias. We propose that these landforms, the result of crustal shortening in response to global contraction, formed along the interface between the basin floor and the smooth plains unit, which acted as a mechanical discontinuity along which shortening strains were concentrated.

  2. CRISP: Cutting Edge Reconfigurable ICs for Stream Processing

    NARCIS (Netherlands)

    Ahonen, Tapani; ter Braak, T.D.; Burgess, Stephen T.; Geißler, Richard; Heysters, P.M.; Hurskainen, Heikki; Kerkhoff, Hans G.; Kokkeler, Andre B.J.; Nurmi, Jari; Raasakka, Jussi; Rauwerda, G.K.; Smit, Gerardus Johannes Maria; Zhang, X.; Sunesen, Kim; van Zonneveld, Henk; Vermeulen, Bart; Cardoso, João M.P.; Hübner, Michael

    2011-01-01

    The Cutting edge Reconfigurable ICs for Stream Processing (CRISP) project aims to create a highly scalable and dependable reconfigurable system concept for a wide range of tomorrow’s streaming DSP applications. Within CRISP, a network-on-chip based many-core stream processor with dependability

  3. The problem of isotropic rectangular plate with four clamped edges

    Indian Academy of Sciences (India)

    This report discusses in exact solution of the governing equation of an isotropic rectangular plate with four clamped edges. A numerical method for clamped isotropic rectangular plate under distributed loads and an exact solution of the governing equation in terms of trigonometric and hyperbolic function are given. Finally ...

  4. Edge detection methods based on generalized type-2 fuzzy logic

    CERN Document Server

    Gonzalez, Claudia I; Castro, Juan R; Castillo, Oscar

    2017-01-01

    In this book four new methods are proposed. In the first method the generalized type-2 fuzzy logic is combined with the morphological gra-dient technique. The second method combines the general type-2 fuzzy systems (GT2 FSs) and the Sobel operator; in the third approach the me-thodology based on Sobel operator and GT2 FSs is improved to be applied on color images. In the fourth approach, we proposed a novel edge detec-tion method where, a digital image is converted a generalized type-2 fuzzy image. In this book it is also included a comparative study of type-1, inter-val type-2 and generalized type-2 fuzzy systems as tools to enhance edge detection in digital images when used in conjunction with the morphologi-cal gradient and the Sobel operator. The proposed generalized type-2 fuzzy edge detection methods were tested with benchmark images and synthetic images, in a grayscale and color format. Another contribution in this book is that the generalized type-2 fuzzy edge detector method is applied in the preproc...

  5. A comparative analysis of watershed and edge based segmentation ...

    African Journals Online (AJOL)

    MJP

    2015-03-17

    Mar 17, 2015 ... Background: Useful information which is helpful in the diagnosis of various disorders is obtained from the analysis of individual blood cells. Aim: To perform a comparative analysis between edge-based segmentation and watershed segmentation on images of the red blood cells. Method: The images.

  6. Exploring the Uncanny Valley to Find the Edge of Play

    Science.gov (United States)

    Eberle, Scott G.

    2009-01-01

    Play often rewards us with a thrill or a sense of wonder. But, just over the edge of play, uncanny objects like dolls, automata, robots, and realistic animations may become monstrous rather than marvelous. Drawing from diverse sources, literary evidence, psychological and psychoanalytic theory, new insights in neuroscience, marketing literature,…

  7. Tactical Cloudlets: Moving Cloud Computing to the Edge

    NARCIS (Netherlands)

    Lewis, G.A.; Echeverria, S.; Simanta, S.; Bradshaw, B.; Root, J.

    2014-01-01

    Soldiers and front-line personnel operating in tactical environments increasingly make use of handheld devices to help with tasks such as face recognition, language translation, decision-making, and mission planning. These resource constrained edge environments are characterized by dynamic context,

  8. Edge effect in charged-particle analyzing magnets

    NARCIS (Netherlands)

    Braams, C.M.

    The manner in which local saturation of pole pieces with sharp edges affects the fall-off of the magnetic induction in the fringing-field region is discussed and measured. Local saturation appears to set in at a field strength well below that at which over-all saturation of the pole pieces becomes

  9. Weighting links based on edge centrality for community detection

    Science.gov (United States)

    Sun, Peng Gang

    2014-01-01

    Link weights have the equally important position as links in complex networks, and they are closely associated with each other for the emergence of communities. How to assign link weights to make a clear distinction between internal links of communities and external links connecting communities is of vital importance for community detection. Edge centralities provide a powerful approach for distinguishing internal links from external ones. Here, we first use edge centralities such as betweenness, information centrality and edge clustering coefficient to weight links of networks respectively to transform unweighted networks into weighted ones, and then a weighted function that both considers links and link weights is adopted on the weighted networks for community detection. We evaluate the performance of our approach on random networks as well as real-world networks. Better results are achieved on weighted networks with stronger weights of internal links of communities, and the results on unweighted networks outperform that of weighted networks with weaker weights of internal links of communities. The availability of our findings is also well-supported by the study of Granovetter that the weak links maintain the global integrity of the network while the strong links maintain the communities. Especially in the Karate club network, all the nodes are correctly classified when we weight links by edge betweenness. The results also give us a more comprehensive understanding on the correlation between links and link weights for community detection.

  10. Chemical shift of UL 3 edges in different uranium compounds ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 37; Issue 3. Chemical shift of U L3 edges in different uranium compounds obtained by X-ray absorption spectroscopy with synchrotron radiation. D Joseph C Nayak P Venu Babu S N Jha D Bhattacharyya. Volume 37 Issue 3 May 2014 pp 643-647 ...

  11. Characterization of Edge Localized Modes in Tokamak Plasmas

    NARCIS (Netherlands)

    Boom, J. E.

    2012-01-01

    To mimic the fusion of hydrogen nuclei in the sun as an energy source on Earth, fusion scientists have to deal with miniature solar flares in their nuclear fusion reactor. These 'Edge Localized Modes' (ELMs) can damage the wall of the reactor. Physicist Jurrian Boom from the FOM Institute

  12. Differential Privacy for Edge Weights in Social Networks

    Directory of Open Access Journals (Sweden)

    Xiaoye Li

    2017-01-01

    Full Text Available Social networks can be analyzed to discover important social issues; however, it will cause privacy disclosure in the process. The edge weights play an important role in social graphs, which are associated with sensitive information (e.g., the price of commercial trade. In the paper, we propose the MB-CI (Merging Barrels and Consistency Inference strategy to protect weighted social graphs. By viewing the edge-weight sequence as an unattributed histogram, differential privacy for edge weights can be implemented based on the histogram. Considering that some edges have the same weight in a social network, we merge the barrels with the same count into one group to reduce the noise required. Moreover, k-indistinguishability between groups is proposed to fulfill differential privacy not to be violated, because simple merging operation may disclose some information by the magnitude of noise itself. For keeping most of the shortest paths unchanged, we do consistency inference according to original order of the sequence as an important postprocessing step. Experimental results show that the proposed approach effectively improved the accuracy and utility of the released data.

  13. Automatic Color Sorting of Hardwood Edge-Glued Panel Parts

    Science.gov (United States)

    D. Earl Kline; Richard Conners; Qiang Lu; Philip A. Araman

    1997-01-01

    This paper describes an automatic color sorting system for red oak edge-glued panel parts. The color sorting system simultaneously examines both faces of a panel part and then determines which face has the "best" color, and sorts the part into one of a number of color classes at plant production speeds. Initial test results show that the system generated over...

  14. A comparative analysis of watershed and edge based segmentation ...

    African Journals Online (AJOL)

    Background: Useful information which is helpful in the diagnosis of various disorders is obtained from the analysis of individual blood cells. Aim: To perform a comparative analysis between edge-based segmentation and watershed segmentation on images of the red blood cells. Method: The images to be used for the ...

  15. Fast Edge-Aware Processing via First Order Proximal Approximation.

    Science.gov (United States)

    Badri, Hicham; Yahia, Hussein; Aboutajdine, Driss

    2015-06-01

    We present a new framework for fast edge-aware processing of images and videos. The proposed smoothing method is based on an optimization formulation with a non-convex sparse regularization for a better smoothing behavior near strong edges. We develop mathematical tools based on first order approximation of proximal operators to accelerate the proposed method while maintaining high-quality smoothing. The first order approximation is used to estimate a solution of the proximal form in a half-quadratic solver, and also to derive a warm-start solution that can be calculated quickly when the image is loaded by the user. We extend the method to large-scale processing by estimating the smoothing operation with independent 1D convolution operations. This approach linearly scales to the size of the image and can fully take advantage of parallel processing. The method supports full color filtering and turns out to be temporally coherent for fast video processing. We demonstrate the performance of the proposed method on various applications including image smoothing, detail manipulation, HDR tone-mapping, fast edge simplification and video edge-aware processing.

  16. A Brooks type theorem for the maximum local edge connectivity

    DEFF Research Database (Denmark)

    Stiebitz, Michael; Toft, Bjarne

    2018-01-01

    For a graph $G$, let $\\cn(G)$ and $\\la(G)$ denote the chromatic number of $G$ and the maximum local edge connectivity of $G$, respectively. A result of Dirac \\cite{Dirac53} implies that every graph $G$ satisfies $\\cn(G)\\leq \\la(G)+1$. In this paper we characterize the graphs $G$ for which $\\cn(G)...

  17. Compact L-edge densitometer for uranium concentration assay

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, M.L.; Russo, P.A.; Sprinkle, J.K. Jr.

    1985-02-01

    A new L-edge densitometer has been designed around a compact, commercial x-ray generator weighing less than 5 kg. The dc generator x-ray spectrum was tailored to produce a continuum of x-ray energies from 14 to 20 keV. The x rays were transmitted through uranium reference solutions, and the measured transmissions near the uranium L/sub III/-absorption edge were used to compute the uranium concentration assay result. The range of uranium concentrations in the reference solutions included 5 to 50 g/l. In this concentration range, the assay uncertainty for short count times and the flatness of the specific assay response were better than 0.5%. Thus, the precision and accuracy of this compact densitometer are equal to those demonstrated previously for the L-edge technique. The compact dimensions and optimized transmission geometry increase the practicality, versatility, and range of the L-edge applications. 12 references, 12 figures, 4 tables.

  18. Edge detection of digital color images using information sets

    Science.gov (United States)

    Arora, Shaveta; Hanmandlu, Madasu; Gupta, Gaurav

    2016-11-01

    Most image processing and computer vision applications require edge detection for object recognition, image segmentation, and scene analysis. The traditional algorithms cannot handle the demanding requirements on the accuracy and robustness of these applications. Information set theory is utilized in this paper for defining edge strength measures which help in finding robust edges. The proposed work is originated from the smallest univalue segment assimilating nucleus concept, wherein a mask is applied on the red, green, and blue components of the color image for calculating a small area of neighboring pixels with similar brightness to center pixels. A symmetric Gaussian membership function (MF) is used to fuzzify the histogram of this area. This MF is converted into sigmoidal MF to strengthen and sharpen the weak edges. These two MFs provide the best results in comparison to other MFs used in literature. Extensive simulation results show that the proposed technique produces better results than other existing techniques in terms of the qualitative and quantitative measures, which include Pratt's figure of merit, structural similarity index, and analysis of variance. The proposed technique also works well in the presence of impulse noise.

  19. Simulated dry deposition of nitric acid near forest edges

    NARCIS (Netherlands)

    DeJong, JJM; Klaassen, W; Jong, J.J.M. de

    1997-01-01

    Dry deposition is simulated to understand and generalize observations of enhanced deposition of air pollution near forest edges. Nitric acid is taken as an example as its deposition velocity is often assumed to be determined by turbulent transport only. The simulations are based on the

  20. Subcomponent testing of trailing edge panels in wind turbine blades

    DEFF Research Database (Denmark)

    Branner, Kim; Berring, Peter; Haselbach, Philipp Ulrich

    2016-01-01

    This paper proposes a static subcomponent test method designed to check the compressive strength of the trailing edge region in wind turbine blades under a simplified loading. The paper presents numerical simulations using the proposed subcomponent test method and discusses its ability to be used...

  1. Critical shear stress produced by interaction of edge dislocation with ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. According to the Mott and Nabarro's model, the contribution to the critical shear stress of the material caused by the interaction between edge dislocations and nanoscale cylindrical inhomogeneities with interface stresses is obtained. The influence of the radius and the volume fraction of the inhomogeneity as well.

  2. Development of smart blade technology - trailing edge flaps

    DEFF Research Database (Denmark)

    Aagaard Madsen, Helge

    2014-01-01

    With blade lengths presently up to 80+ m there is a need for a supplement to the standard pitch system for control of power and loads. Distributed load control along the blade span with trailing edge flaps is a promising concept where numerical simulations have shown considerable load alleviation...

  3. On the Dynamics of Edge-core Coupling

    Energy Technology Data Exchange (ETDEWEB)

    Hahm,T.S.; Diamond, P.H.; Lin, Z.; Rewoldt, G.; Gurcan, O.; Ethier, S.

    2005-08-26

    One of the nagging, unresolved questions in fusion theory is concerned with the extent of the edge. Gyrokinetic particle simulations of toroidal ion temperature gradient (ITG) turbulence spreading using the Gyrokinetic Toroidal Code (GTC) [Z. Lin et al., Science 281, 1835 (1998)] and its related dynamical model have been extended to a system with radially varying ion temperature gradient, in order to study the inward spreading of edge turbulence toward the core plasma. Due to such spreading, the turbulence intensity in the core region is significantly enhanced over the value obtained from simulations of the core region only, and the precise boundary of the edge region is blurred. Even when the core gradient is within the Dimits shift regime (i.e., dominated by self-generated zonal flows which reduce the transport to a negligible value), a significant level of turbulence can penetrate to the core due to spreading from the edge. The scaling of the turbulent front propagation speed is closer to the prediction from a nonlinear diffusion model than from one based on linear toroidal coupling.

  4. The sensitivity of tokamak magnetohydrodynamics stability on the edge equilibrium

    Science.gov (United States)

    Zheng, L. J.; Kotschenreuther, M. T.; Valanju, P.

    2017-10-01

    Due to the X-point singularity, the safety factor tends to infinity as approaching to the last closed flux surface. The numerical treatments of the near X-point behavior become challenging both for equilibrium and stability. The usual solution is to cut off a small fraction of edge region for system stability evaluation or simply use an up-down symmetric equilibrium without X-point as an approximation. In this work, we assess the sensitivity of this type of equilibrium treatments on the stability calculation. It is found that the system stability can depend strongly on the safety factor value (qa) at the edge after the cutting-off. When the edge safety factor value falls in the vicinity of a rational mode number (referred to as the resonant gap), the system becomes quite unstable due to the excitation of the peeling type modes. Instead, when the edge safety factor is outside the resonant gaps, the system is much more stable and the predominant modes become the usual external kink (or ballooning and infernal) type. It is also found that the resonant gaps become smaller and smaller as qa increases. The ideal magnetohydrodynamic peeling ballooning stability diagram is widely used to explain the experimental observations, and the current results indicate that the conventional peeling ballooning stability diagram based on the simplified equilibrium needs to be reexamined.

  5. Living on the Future Edge: Windows on Tomorrow

    Science.gov (United States)

    Jukes, Ian; McCain, Ted; Crockett, Lee

    2010-01-01

    "Living on the Future Edge" challenges school leaders to rethink longstanding paradigms and transform pedagogy for tomorrow's learners. Apple Computer, Inc. co-founder Steve Wozniak's foreword underscores the overwhelming need to adjust traditional instruction to fit today's high-tech world. The book explores this new landscape and…

  6. Rotational accelerations stabilize leading edge vortices on revolving fly wings

    NARCIS (Netherlands)

    Lentink, D.; Dickinson, M.H.

    2009-01-01

    The aerodynamic performance of hovering insects is largely explained by the presence of a stably attached leading edge vortex (LEV) on top of their wings. Although LEVs have been visualized on real, physically modeled, and simulated insects, the physical mechanisms responsible for their stability

  7. InAs Band-Edge Exciton Fine Structure

    Science.gov (United States)

    2015-07-29

    modulated by the excitation rate of the nanocrystals, fine-structure broadening is fundamental to the photophysics of nanocrystals and most likely... CdTe ) exhibited the same effective band-edge fine structure, with similar acoustic phonon energies. These extracted relaxation rates are consistent

  8. Dirac and Majorana edge states in graphene and topological superconductors

    NARCIS (Netherlands)

    Akhmerov, Anton Roustiamovich

    2011-01-01

    This dissertation is about transport and electronic properties of two types of electronic states occuring at the edges, which are protected by symmetry between positive and negative energies. One type of these states is shown to occur universally in graphene. It is also described how another type of

  9. Edge-ratio network clustering by Variable Neighborhood Search

    Science.gov (United States)

    Cafieri, Sonia; Hansen, Pierre; Mladenović, Nenad

    2014-05-01

    The analysis of networks and in particular the identification of communities, or clusters, is a topic of active research with applications arising in many domains. Several models were proposed for this problem. In reference [S. Cafieri, P. Hansen, L. Liberti, Phys. Rev. E 81, 026105 (2010)], a criterion is proposed for a graph bipartition to be optimal: one seeks to maximize the minimum for both classes of the bipartition of the ratio of inner edges to cut edges ( edge-ratio), and it is used in a hierarchical divisive algorithm for community identification in networks. In this paper, we develop a VNS-based heuristic for hierarchical divisive edge-ratio network clustering. A k-neighborhood is defined as move of k entities, i.e., k entities change their membership from one to another cluster. A local search is based on 1-changes and k-changes are used for shaking the incumbent solution. Computational results on datasets from the literature validate the proposed approach.

  10. Information professionalism in a digital age: cutting edge ...

    African Journals Online (AJOL)

    ... that is devoted to information management in order to meet the demands of the new environment. With professional activities and institutions migrating to the Web, professionals with the appropriate skills will have a competitive edge over others lacking in skills required to operate in the emerging practice environment.

  11. Phase knife-edge laser Schlieren diffraction interferometry with ...

    Indian Academy of Sciences (India)

    581–589. Phase knife-edge laser Schlieren diffraction interferometry with boundary diffraction wave theory. RAJ KUMAR1, D MOHAN2, SUSHIL K KAURA1, D P CHHACHHIA1 and A K AGGARWAL1 ... contrast but also avoids the loss in phase information as it lets through light from all parts of the test object and its thin ...

  12. On a conjecture about edge irregular total labelings

    DEFF Research Database (Denmark)

    Brandt, Stephan; Rautenbach, D.; Miškuf, J.

    2008-01-01

    ′V. Functions with this property were recently introduced and studied by Bača et al. and were called edge irregular total labelings. Our result confirms a recent conjecture of Ivančo and Jendrol' about such labelings for dense graphs, for graphs where the maximum and minimum degree are not too different...

  13. A high-performance, low-cost, leading edge discriminator

    Indian Academy of Sciences (India)

    A high-performance, low-cost, leading edge discriminator has been designed with a timing performance comparable to state-of-the-art, commercially available ... Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India; Graduate School of Science, Osaka City University, Osaka 558-8585, Japan ...

  14. Concave serrations on broadband trailing edge noise reduction

    NARCIS (Netherlands)

    Ragni, D.; Avallone, F.; van der Velden, W.C.P.

    2017-01-01

    The far-field noise and flow field of a novel curved trailing-edge serration (i.e. iron-shaped) are investigated. Spectra of the far-field broadband noise, directivity plots and the flow-field over the iron-shaped serration are obtained from numerical computations performed using a compressible

  15. Airfoil Trailing Edge Noise Generation and Its Surface Pressure Fluctuation

    DEFF Research Database (Denmark)

    Zhu, Wei Jun; Shen, Wen Zhong

    2015-01-01

    where the time history pressure data are recorded by the surface pressure microphones. After the flow-field is stabilized, the generated noise from the airfoil Trailing Edge (TE) is predicted using the acoustic analogy solver, where the results from LES are the input. It is found that there is a strong...

  16. Flow and edge scour in current adjacent to stone covers

    DEFF Research Database (Denmark)

    Petersen, Thor U.; Sumer, B. Mutlu; Bøgelund, Jon

    2015-01-01

    This paper presents the results of an experimental investigation on edge scour adjacent to a stone cover laid on a sandy bed. The three-dimensional flow over the edge of the stone layer has been investigated by the use of particle image velocimetry. The flow measurements show a significant amount...... of turbulence in the primary flow near the junction between the stone layer and the sand bed and the formation of complex secondary-flow structures. The results show that the flow and the edge scour process in a steady current are governed by the size of the roughness elements and to some extent the side slope...... of the berm. The edge scour is caused by the combined action of the primary flow and the secondary flow. The primary flow stirs up the sediment and puts it into suspension, and the secondary flow carries it away from the junction between the stone layer and the sand bed, resulting in a scour hole forming...

  17. Edge Detector Design Based on LS-SVR

    Directory of Open Access Journals (Sweden)

    Zhongdang Yu

    2014-01-01

    Full Text Available For locating inaccurate problem of the discrete localization criterion proposed by Demigny, a new criterion expression of “good localization” is proposed. Firstly, a discrete expression of good detection and good localization criterion of two dimension edge detection operator is employed, and then an experiment to measure optimal parameters of two dimension Canny's edge detection operator is introduced after. Moreover, a detailed performance comparison and analysis of two dimension optimal filter obtained via utilizing tensor product for one dimension optimal filter are provided which can prove that least square support vector regression (LS-SVR is a smoothness filter and give the construct method of the derivate operator. This paper uses LS-SVR as the object function constructor and then realizes the approximation of two dimension optimal edge detection operator. This paper proposes the utility method of using singleness operator to realize multiscale edge detection by referencing the multiscale analysis technology of the wavelets theory. Experiment shows that the method has utility and efficiency.

  18. SciDAC-Center for Plasma Edge Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Choong Seock

    2012-06-04

    The SciDAC ProtoFSP Center for Plasma Edge Simulation (CPES) [http://www.cims.nyu.edu/cpes/] was awarded to New York University, Courant Institute of Mathematical Sciences in FY 2006. C.S. Chang was the institutional and national project PI. It's mission was 1) to build kinetic simulation code applicable to tokamak edge region including magnetic divertor geometry, 2) to build a computer science framework which can integrate the kinetic code with MHD/fluid codes in multiscale, 3) to conduct scientific research using the developed tools. CPES has built two such edge kinetic codes XGC0 and XGC1, which are still the only working kinetic edge plasma codes capable of including the diverted magnetic field geometry. CPES has also built the code coupling framework EFFIS (End-to-end Framework for Fusion Integrated Simulation), which incubated and used the Adios (www.olcf.ornl.gov/center-projects/adios/) and eSiMon (http://www.olcf.ornl.gov/center-projects/esimmon/) technologies, together with the Kepler technology.

  19. Fiction, History and Pedagogy: A Double-Edged Sword

    Science.gov (United States)

    Clark, Penney; Sears, Alan

    2017-01-01

    There are many areas of overlap between history and fiction. Teachers of history have long recognized this connection and used a range of fictional accounts in their teaching. In this article, we argue that fiction is a double-edged sword that must be handled carefully. On the one hand, it presents compelling characters and accounts that provide…

  20. Ballistic edge states in Bismuth nanowires revealed by SQUID interferometry

    Science.gov (United States)

    Murani, Anil; Kasumov, Alik; Sengupta, Shamashis; Kasumov, Yu A.; Volkov, V. T.; Khodos, I. I.; Brisset, F.; Delagrange, Raphaëlle; Chepelianskii, Alexei; Deblock, Richard; Bouchiat, Hélène; Guéron, Sophie

    2017-07-01

    The protection against backscattering provided by topology is a striking property. In two-dimensional insulators, a consequence of this topological protection is the ballistic nature of the one-dimensional helical edge states. One demonstration of ballisticity is the quantized Hall conductance. Here we provide another demonstration of ballistic transport, in the way the edge states carry a supercurrent. The system we have investigated is a micrometre-long monocrystalline bismuth nanowire with topological surfaces, that we connect to two superconducting electrodes. We have measured the relation between the Josephson current flowing through the nanowire and the superconducting phase difference at its ends, the current-phase relation. The sharp sawtooth-shaped phase-modulated current-phase relation we find demonstrates that transport occurs selectively along two ballistic edges of the nanowire. In addition, we show that a magnetic field induces 0-π transitions and ϕ0-junction behaviour, providing a way to manipulate the phase of the supercurrent-carrying edge states and generate spin supercurrents.

  1. Parallel greedy graph matching using an edge partitioning approach

    NARCIS (Netherlands)

    Patwary, M.M.A.; Bisseling, R.H.; Manne, F.

    2010-01-01

    We present a parallel version of the Karp-Sipser graph matching heuristic for the maximum cardinality problem. It is bulksynchronous, separating computation and communication, and uses an edge-based partitioning of the graph, translated from a twodimensional partitioning of the corresponding

  2. Upsetting Butt Edge Increases Weld-Joint Strength

    Science.gov (United States)

    Vesco, D.

    1964-01-01

    Mechanical upsetting /a mode of cold forging/ of butt edges to be welded is accomplished by the use of hydraulic rams and pressure rollers. The mechanical upsetting increases the thickness of the material in the heat-affected zone and compensates for the lower specific strength per unit thickness common to this area.

  3. Silicon Nanowire Fabrication Using Edge and Corner Lithography

    NARCIS (Netherlands)

    Yagubizade, H.; Berenschot, Johan W.; Jansen, Henricus V.; Elwenspoek, Michael Curt; Tas, Niels Roelof

    2010-01-01

    This paper presents a wafer scale fabrication method of single-crystalline silicon nanowires (SiNWs) bound by <111> planes using a combination of edge and corner lithography. These are methods of unconventional nanolithography for wafer scale nano-patterning which determine the size of nano-features

  4. Transfrontier Conservation Areas: people living on the edge

    NARCIS (Netherlands)

    Andersson, J.A.; Garine-Wichatitsky, de M.; Cumming, D.H.M.; Dzingirai, V.; Giller, K.E.

    2013-01-01

    This book focuses on the forgotten people displaced by, or living on the edge of, protected wildlife areas. It moves beyond the grand 'enchanting promise' of conservation and development across frontiers, and unfounded notions of TFCAs as integrated social-ecological systems. Peoples' dependency on

  5. The role of step edge diffusion in epitaxial crystal growth

    NARCIS (Netherlands)

    Schinzer, S.; Kinne, M.; Biehl, M.; Kinzel, W.

    1999-01-01

    The role of step edge diffusion (SED) in epitaxial growth is investigated. To this end we revisit and extend a recently introduced simple cubic solid-on-solid model, which exhibits the formation and coarsening of pyramid or mound-like structures. By comparing the limiting cases of absent, very fast

  6. Color edge saliency boosting using natural image statistics

    NARCIS (Netherlands)

    Rojas Vigo, D.; van de Weijer, J.; Gevers, T.

    2010-01-01

    State of the art methods for image matching, content-based retrieval and recognition use local features. Most of these still exploit only the luminance information for detection. The color saliency boosting algorithm has provided an efficient method to exploit the saliency of color edges based on

  7. Investigating environmental trends in the outer visible edges of dwarf irregular galaxies

    Science.gov (United States)

    Dunn, Jacqueline M.

    2017-03-01

    The star formation histories and evolution of 28 dwarf irregular galaxies (dIs) that reside in differing local and global environments are investigated. The shallow gravitational potentials of dwarf galaxies make these objects highly susceptible to changes in morphology or dynamics by external perturbations. Additionally, the lack of more complicated structures such as spiral arms makes environmental effects more easily discernible. Therefore, dIs are ideal candidates for a study of the role of environment in galaxy evolution. The local environment is defined by the local galaxy number density, where high indicates at least one neighbor within 200 kpc and low indicates no neighbors within 1 Mpc. The global environment is classified as either the field or a galaxy group / cluster. Absolute magnitudes, colors, central surface brightnesses, star formation rates and color profiles were compared using photometry from UBVR and Hα imaging. While some environmental trends are noted (galaxies in local high density environments have brighter central and effective surface brightnesses, while those in global high density environments have brighter absolute magnitudes, central and effective surface brightnesses, and higher star formation rates), no systematic environmental trends are seen in the shape of the color profiles or spatial distribution of recent star formation. A lack of environmental trend in star formation and galaxy color indicates that either internal processes dominate the formation and subsequent evolution of the outskirts of dIs, or there is no systematic environmental effect on such. The appearance of environmental effects should be more noticeable at the outermost edges of these systems. The lack of a trend in such implies that the exact nature of the environmental influence varies greatly depending on the exact nature of the interaction occurring.

  8. Integrated region and edge segmentation using information divergence measures

    Science.gov (United States)

    Hibbard, Lyndon S.

    2004-05-01

    Accurate models of human anatomy are obligatory for modern cancer radiotherapy. Maps of individual patient anatomies are usually drawn manually from CT images. Manual contouring is expensive and time-consuming because of the complexity of the anatomy, the low contrast of soft tissues in CT, and blurred image detail due to respiratory motion. We have developed automated contouring methods based on relative entropy and more general divergence measures from information theory and statistics that produce average minimum error inference like the traditional maximum likelihood (ML) and maximum a posteriori (MAP) classifiers. Unlike the ML/MAP classifiers that are frequently implemented assuming Gaussian models for the data, the information theoretic divergences require no data model. We have concentrated on the Jensen-Renyi divergence (JRD) by which multiple contours can be obtained simultaneously with the optimization of a single objective function. Region segmentation is accomplished by maximizing the divergence of pixel feature distributions inside and outside a flexible, closed, parametric curve. Recently we have integrated multivariate region segmentation with edge detection, also done by maximizing the JRD over sets of region-interior and region-edge pixels in edge-enhanced versions of the image. Further, region and edge detection are combined with prior shape constraints in which the combined JRD objective function is penalized if the flexible curve parameters deviate too far from those of a prior known shape. Though the performance of the JRD program is a complex function of pixel feature number and kind, edges, and shape priors, we demonstrate accurate contours computed from image data distributions and estimates of prior shape.

  9. SciDAC - Center for Plasma Edge Simulation - Project Summary

    Energy Technology Data Exchange (ETDEWEB)

    Parker, Scott [Univ. of Colorado, Boulder, CO (United States)

    2014-11-03

    Final Technical Report: Center for Plasma Edge Simulation (CPES) Principal Investigator: Scott Parker, University of Colorado, Boulder Description/Abstract First-principle simulations of edge pedestal micro-turbulence are performed with the global gyrokinetic turbulence code GEM for both low and high confinement tokamak plasmas. The high confinement plasmas show a larger growth rate, but nonlinearly a lower particle and heat flux. Numerical profiles are obtained from the XGC0 neoclassical code. XGC0/GEM code coupling is implemented under the EFFIS (“End-to-end Framework for Fusion Integrated Simulation”) framework. Investigations are underway to clearly identify the micro-instabilities in the edge pedestal using global and flux-tube gyrokinetic simulation with realistic experimental high confinement profiles. We use both experimental profiles and those obtained using the EFFIS XGC0/GEM coupled code framework. We find there are three types of instabilities at the edge: a low-n, high frequency electron mode, a high-n, low frequency ion mode, and possibly an ion mode like kinetic ballooning mode (KBM). Investigations are under way for the effects of the radial electric field. Finally, we have been investigating how plasmas dominated by ion-temperature gradient (ITG) driven turbulence, how cold Deuterium and Tritium ions near the edge will naturally pinch radially inward towards the core. We call this mechanism “natural fueling.” It is due to the quasi-neutral heat flux dominated nature of the turbulence and still applies when trapped and passing kinetic electron effects are included. To understand this mechanism, examine the situation where the electrons are adiabatic, and there is an ion heat flux. In such a case, lower energy particles move inward and higher energy particles move outward. If a trace amount of cold particles are added, they will move inward.

  10. Evaluation of the EDGE detector in small-field dosimetry

    Science.gov (United States)

    Shin, Hun-Joo; Kim, Myong-Ho; Choi, Ihl-Bohng; Kang, Young-nam; Kim, Dae-Hyun; Chio, Byung Ock; Jang, Hong Seok; Jung, Ji-Young; Son, Seok Hyun; Kay, Chul Seung

    2013-07-01

    This study evaluates a new diode detector design for small-field dosimetry. An accurate detector that has a small volume are necessary to compile data for stereotactic radiosurgery (SRS), stereotactic body radiotherapy (SBRT), and intensity-modulated radiotherapy (IMRT). Two semiconductor diode detectors and one ionization chamber were used to measure the profiles, percent depth doses (PDDs), and relative output factors (OFs) of a Novalis 6-MV SRS beam. Profiles and PDD data were collected using 5.0-, 10.0-, 15.0-, 20.0-, 30.0-, and 50.0-mm micro multileaf collimators (mMLCs) at small fields and a 98.0 × 98.0-mm2 reference field. OFs were collected for each of the mMLCs. The EDGE diode detector, the diode detector, and the ion chamber (0.007 cc) were used in the study. Detector measurements were performed using the 3D water phantom with a source-to-surface distance of 100-cm at a depth of 1.5-cm. The measurements were analyzed using the IBA OmniPro Accept 7th version software. In addition, all data were compared to Monte Carlo simulations. The semiconductor diodes had similar OFs and PDDs for each of the mMLCs used. The Dmax values of the EDGE diode detector, measured from the PDD, ranged from 8.5 to 14.0-mm with an average of 12.4-mm. The field widths of the EDGE diode detector were found to have similar values. The performance of the EDGE diode detector was comparable for all small-field measurements. Additionally, no evidence of an energy response was observed for the EDGE detectors for a field of 98 × 98-mm2. This is particularly important when measuring the relative OF for small fields or gathering larger-sized field data for the commissioning of a treatment planning system.

  11. Oxygen evolution reaction catalysis

    Science.gov (United States)

    Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.

    2016-09-06

    An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

  12. Museums teach evolution.

    Science.gov (United States)

    Diamond, Judy; Evans, E Margaret

    2007-06-01

    Natural history museums play a significant role in educating the general public about evolution. This article describes Explore Evolution, one of the largest evolution education projects funded by the National Science Foundation. A group of regional museums from the Midwestern United States worked with leading evolutionary scientists to create multiple permanent exhibit galleries and a curriculum book for youth. This program invites the public to experience current evolutionary research on organisms that range in size from HIV to whales. Learning research is being conducted on museum visitors to understand how they reason about evolution and to determine what influences the process of conceptual change.

  13. Adaptability and evolution.

    Science.gov (United States)

    Bateson, Patrick

    2017-10-06

    The capacity of organisms to respond in their own lifetimes to new challenges in their environments probably appeared early in biological evolution. At present few studies have shown how such adaptability could influence the inherited characteristics of an organism's descendants. In part, this has been because organisms have been treated as passive in evolution. Nevertheless, their effects on biological evolution are likely to have been important and, when they occurred, accelerated the pace of evolution. Ways in which this might have happened have been suggested many times since the 1870s. I review these proposals and discuss their relevance to modern thought.

  14. Leading-edge flow reattachment and the lateral static stability of low-aspect-ratio rectangular wings

    Science.gov (United States)

    Linehan, Thomas; Mohseni, Kamran

    2017-11-01

    The relationship between lateral static stability derivative, Clβ,lift coefficient, CL, and angle of attack was investigated for rectangular wings of aspect ratio A R =0.75 ,1 ,1.5 , and 3 using Stereo-Digital Particle Image Velocimetry (S-DPIV) and direct force and moment measurements. When the product Cl βA R is plotted with respect to CL, the lateral stability curves of each wing collapse to a single line for CL0.7 , the linearity and scaling of Clβwith respect to CL is lost. S-DPIV is used to elucidate the flow physics in this nonlinear regime. At α =10∘ , the leading-edge separation region emerges on the leeward portion of the sideslipped wing by means of vortex shedding. For the A R ≤1.5 wings at α >15∘ , the tip vortex downwash is sufficient to restrict the shedding of leading-edge vorticity thereby sustaining the lift of the leading-edge separation region at high angles of attack. Concurrently, the windward tip vortex grows in size and strength with increasing angle of attack, displacing the leading-edge separation region further toward the leeward wing. This reorganization of lift-generating vorticity results in the initial nonlinearities between Cl β and CL at angles of attack for which CL is still increasing. At angles of attack near that of maximum lift for the A R ≤1 wings, the windward tip vortex lifts off the wing, decreasing the lateral static stability of the wing prior to lift stall. For the A R =3 wing at α >10∘ , nonlinear trends in Cl β versus CL occur due to the spanwise evolution of stalled flow.

  15. Leading-edge flow criticality as a governing factor in leading-edge vortex initiation in unsteady airfoil flows

    Science.gov (United States)

    Ramesh, Kiran; Granlund, Kenneth; Ol, Michael V.; Gopalarathnam, Ashok; Edwards, Jack R.

    2017-08-01

    A leading-edge suction parameter (LESP) that is derived from potential flow theory as a measure of suction at the airfoil leading edge is used to study initiation of leading-edge vortex (LEV) formation in this article. The LESP hypothesis is presented, which states that LEV formation in unsteady flows for specified airfoil shape and Reynolds number occurs at a critical constant value of LESP, regardless of motion kinematics. This hypothesis is tested and validated against a large set of data from CFD and experimental studies of flows with LEV formation. The hypothesis is seen to hold except in cases with slow-rate kinematics which evince significant trailing-edge separation (which refers here to separation leading to reversed flow on the aft portion of the upper surface), thereby establishing the envelope of validity. The implication is that the critical LESP value for an airfoil-Reynolds number combination may be calibrated using CFD or experiment for just one motion and then employed to predict LEV initiation for any other (fast-rate) motion. It is also shown that the LESP concept may be used in an inverse mode to generate motion kinematics that would either prevent LEV formation or trigger the same as per aerodynamic requirements.

  16. Barlow's Mitral Valve Disease: A Comparison of Neochordal (Loop) and Edge-To-Edge (Alfieri) Minimally Invasive Repair Techniques.

    Science.gov (United States)

    da Rocha E Silva, Jaqueline G; Spampinato, Ricardo; Misfeld, Martin; Seeburger, Joerg; Pfanmüller, Bettina; Eifert, Sandra; Mohr, Friedrich W; Borger, Michael A

    2015-12-01

    Barlow's mitral valve (MV) disease remains a surgical challenge. We compared short- and medium-term outcomes of neochordal ("loop") versus edge-to-edge ("Alfieri") minimally invasive MV repair in patients with Barlow's disease. From January 2009 to April 2014, 123 consecutive patients with Barlow's disease (defined as bileaflet billowing or prolapse [or both], excessive leaflet tissue, and annular dilatation with or without calcification) underwent minimally invasive MV operations for severe mitral regurgitation (MR) at our institution. Three patients (2.4%) underwent MV replacement during the study period and were excluded from subsequent analysis. The loop MV repair technique was used in 68 patients (55.3%) and an edge-to-edge repair was performed in 44 patients (35.8%). Patients who underwent a combination of these 2 techniques (n = 8 [6.5%]) were excluded. The median age was 48 years, and 62.5% of patients were men. Concomitant procedures included closure of a patent foramen ovale or atrial septal defect (n = 19), tricuspid valve repair (n = 5), and atrial fibrillation ablation (n = 15). Follow-up was performed 24.7 ± 17 months postoperatively and was 98% complete. No deaths occurred perioperatively or during follow-up. Aortic cross-clamp time (64.1 ± 17.6 minutes versus 95.9 ± 29.5 minutes) and cardiopulmonary bypass (CPB) time (110.0 ± 24.2 minutes versus 146.4 ± 39.1 minutes) were significantly shorter (p mitral orifice area tended to be smaller in this group (2.8 ± 0.7 cm(2) versus 3.0 ± 0.7 cm(2); p = 0.06). The amount of residual MR was similar between groups (0.3 ± 0.6 versus 0.6 ± 1.0 for edge-to-edge versus loop procedures, respectively; p = 0.08). More than mild MR requiring early MV reoperation was present in 3 patients who underwent loop procedures (4.4%) and in no patients who had edge-to-edge procedures (p = 0.51). During follow-up, 2 patients (1 in each group) required MV replacement for severe MR. The 4-year freedom from MV reoperation

  17. An Interactive Procedure to Preserve the Desired Edges during the Image Processing of Noise Reduction

    Directory of Open Access Journals (Sweden)

    Huang Hsuan-Yu

    2010-01-01

    Full Text Available The paper propose a new procedure including four stages in order to preserve the desired edges during the image processing of noise reduction. A denoised image can be obtained from a noisy image at the first stage of the procedure. At the second stage, an edge map can be obtained by the Canny edge detector to find the edges of the object contours. Manual modification of an edge map at the third stage is optional to capture all the desired edges of the object contours. At the final stage, a new method called Edge Preserved Inhomogeneous Diffusion Equation (EPIDE is used to smooth the noisy images or the previously denoised image at the first stage for achieving the edge preservation. The Optical Character Recognition (OCR results in the experiments show that the proposed procedure has the best recognition result because of the capability of edge preservation.

  18. Multifunctional electrocatalytic hybrid carbon nanocables with highly active edges on their walls

    Science.gov (United States)

    Gusmão, Rui; Sofer, Zdeněk; Nováček, Michal; Luxa, Jan; Matějková, Stanislava; Pumera, Martin

    2016-03-01

    Graphene sheets exhibit fast heterogeneous electron transfer at the edges while at the basal plane the electron transfer is much slower. Carbon nanotubes (CNTs) represent fascinating quasi-1-dimensional materials due to their electronic and mechanical properties which enable the formation of (unlike graphene) robust, flexible and well defined three dimensional structures. Because CNTs are created from ``rolled up'' graphene sheets, exposing mostly inactive walls, they generally exhibit poor electrochemical properties. In contrast, graphene sheets can exhibit fast electron transfer rates but are often prone to ``restacking'' which hinders their true electrochemical potential. Here we obviate this problem by partial unzipping of CNTs, where their inner core creates nanocables with high electrical conductivity while the outer unzipped graphene layers full of edges and defects act as highly electroactive materials. Metallic nanoparticles are introduced into graphene oxide/CNT hybrid structures (GOCNT), so they do catalyze reactions which are not catalyzed by carbon. We show that in combination with trace metal doping, these nanocables act as efficient electrocatalysts towards oxidation of biomarkers and energy related applications, such as hydrogen evolution reaction. Such hybrid graphene/CNT/metallic nanoparticles present universal well-structured catalysts which should find wide applications in electrochemical devices. GOCNTs rich in oxygenated groups show much promise in pollution management, thus their adsorption behaviour was investigated to establish their ability to remove harmful heavy-metal pollutants. The results show an increasing trend in the concentration of oxygen functional groups, directly correlated with the GOCNT adsorption capacity.Graphene sheets exhibit fast heterogeneous electron transfer at the edges while at the basal plane the electron transfer is much slower. Carbon nanotubes (CNTs) represent fascinating quasi-1-dimensional materials due to

  19. Investigating the interstellar dust through the Fe K-edge

    Science.gov (United States)

    Rogantini, D.; Costantini, E.; Zeegers, S. T.; de Vries, C. P.; Bras, W.; de Groot, F.; Mutschke, H.; Waters, L. B. F. M.

    2017-12-01

    Context. The chemical and physical properties of interstellar dust in the densest regions of the Galaxy are still not well understood. X-rays provide a powerful probe since they can penetrate gas and dust over a wide range of column densities (up to 1024 cm-2). The interaction (scattering and absorption) with the medium imprints spectral signatures that reflect the individual atoms which constitute the gas, molecule, or solid. Aims: In this work we investigate the ability of high resolution X-ray spectroscopy to probe the properties of cosmic grains containing iron. Although iron is heavily depleted into interstellar dust, the nature of the Fe-bearing grains is still largely uncertain. Methods: In our analysis we use iron K-edge synchrotron data of minerals likely present in the ISM dust taken at the European Synchrotron Radiation Facility. We explore the prospects of determining the chemical composition and the size of astrophysical dust in the Galactic centre and in molecular clouds with future X-ray missions. The energy resolution and the effective area of the present X-ray telescopes are not sufficient to detect and study the Fe K-edge, even for bright X-ray sources. Results: From the analysis of the extinction cross sections of our dust models implemented in the spectral fitting program SPEX, the Fe K-edge is promising for investigating both the chemistry and the size distribution of the interstellar dust. We find that the chemical composition regulates the X-ray absorption fine structures in the post edge region, whereas the scattering feature in the pre-edge is sensitive to the mean grain size. Finally, we note that the Fe K-edge is insensitive to other dust properties, such as the porosity and the geometry of the dust. The absorption, scattering, and extinction cross sections of the compounds are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/A22

  20. Investigating the interstellar dust through the Fe K-edge

    Science.gov (United States)

    Rogantini, D.; Costantini, E.; Zeegers, S. T.; de Vries, C. P.; Bras, W.; de Groot, F.; Mutschke, H.; Waters, L. B. F. M.

    2018-01-01

    Context. The chemical and physical properties of interstellar dust in the densest regions of the Galaxy are still not well understood. X-rays provide a powerful probe since they can penetrate gas and dust over a wide range of column densities (up to 1024 cm-2). The interaction (scattering and absorption) with the medium imprints spectral signatures that reflect the individual atoms which constitute the gas, molecule, or solid. Aims: In this work we investigate the ability of high resolution X-ray spectroscopy to probe the properties of cosmic grains containing iron. Although iron is heavily depleted into interstellar dust, the nature of the Fe-bearing grains is still largely uncertain. Methods: In our analysis we use iron K-edge synchrotron data of minerals likely present in the ISM dust taken at the European Synchrotron Radiation Facility. We explore the prospects of determining the chemical composition and the size of astrophysical dust in the Galactic centre and in molecular clouds with future X-ray missions. The energy resolution and the effective area of the present X-ray telescopes are not sufficient to detect and study the Fe K-edge, even for bright X-ray sources. Results: From the analysis of the extinction cross sections of our dust models implemented in the spectral fitting program SPEX, the Fe K-edge is promising for investigating both the chemistry and the size distribution of the interstellar dust. We find that the chemical composition regulates the X-ray absorption fine structures in the post edge region, whereas the scattering feature in the pre-edge is sensitive to the mean grain size. Finally, we note that the Fe K-edge is insensitive to other dust properties, such as the porosity and the geometry of the dust. The absorption, scattering, and extinction cross sections of the compounds are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/A22