Trailing edge modifications for flatback airfoils.
Kahn, Daniel L.; van Dam, C.P.; 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.
Survey of techniques for reduction of wind turbine blade trailing edge noise.
Barone, Matthew Franklin
2011-08-01
Aerodynamic noise from wind turbine rotors leads to constraints in both rotor design and turbine siting. The primary source of aerodynamic noise on wind turbine rotors is the interaction of turbulent boundary layers on the blades with the blade trailing edges. This report surveys concepts that have been proposed for trailing edge noise reduction, with emphasis on concepts that have been tested at either sub-scale or full-scale. These concepts include trailing edge serrations, low-noise airfoil designs, trailing edge brushes, and porous trailing edges. The demonstrated noise reductions of these concepts are cited, along with their impacts on aerodynamic performance. An assessment is made of future research opportunities in trailing edge noise reduction for wind turbine rotors.
ORIGINAL ARTICLE An experimental investigation on the trailing edge cooling of
Hu, Hui
ORIGINAL ARTICLE An experimental investigation on the trailing edge cooling of turbine blades edge cooling; Wall slot jets; Turbine blades; Steroscopic particle image velocimetry (PIV) measurements characteristics of the wall jets pertinent to trailing edge cooling of turbine blades. A high
Trailing edge noise theory for rotating blades in uniform flow
Sinayoko, Samuel; Agarwal, Anurag
2013-01-01
This paper presents a new formulation for trailing edge noise radiation from rotating blades based on an analytical solution of the convective wave equation. It accounts for distributed loading and the effect of mean flow and spanwise wavenumber. A commonly used theory due to Schlinker and Amiet (1981) predicts trailing edge noise radiation from rotating blades. However, different versions of the theory exist; it is not known which version is the correct one and what the range of validity of the theory is. This paper addresses both questions by deriving Schlinker and Amiet's theory in a simple way and by comparing it to the new formulation, using model blade elements representative of a wind turbine, a cooling fan and an aircraft propeller. The correct form of Schlinker and Amiet's theory (1981) is identified. It is valid at high enough frequency, i.e. for a Helmholtz number relative to chord greater than one and a rotational frequency much smaller than the angular frequency of the noise sources.
Augmentation of Power Output of Axisymmetric Ducted Wind Turbines by Porous Trailing Edge Disks
widnall, sheila
2014-06-30
This paper presents analytical and experimental results that demonstrated that the power output from a ducted wind turbine can be dramatically increased by the addition of a trailing edge device such as a porous disk. In ...
Effects of trailing edge flap dynamic deployment on blade-vortex interactions
Nelson, Carter T.
1997-01-01
A theoretical and experimental investigation is undertaken to determine the effects of an actively deployable trailing edge flap on the disturbances created during blade-vortex interactions (BVI). The theoretical model consists of an unsteady panel...
Study of Trailing-Edge Cooling Using Pressure Sensitive Paint Technique
Hu, Hui
Study of Trailing-Edge Cooling Using Pressure Sensitive Paint Technique Zifeng Yang and Hui Hu Iowa and nitrogen as the coolant stream. The pressure sensitive paint technique was used to map the distribution
An experimental investigation of turbine blade heat transfer and turbine blade trailing edge cooling
Choi, Jungho
2005-02-17
and internal model of a gas turbine blade. It was also used to determine the film effectiveness on the trailing edge. For the internal model, Reynolds numbers based on the hydraulic diameter of iv the exit slot and exit velocity were 5,000, 10,000, 20...-1 AN EXPERIMENTAL INVESTIGATION OF TURBINE BLADE HEAT TRANSFER AND TURBINE BLADE TRAILING EDGE COOLING A Dissertation by JUNGHO CHOI Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements...
Liu, Yao-Hsien
2009-05-15
at the highest rotation number of 0.58. Heat transfer coefficients are also experimentally measured in a wedge-shaped cooling channel (Dh =2.22cm, Ac=7.62cm2) to model an internal cooling passage near the trailing edge of a gas turbine blade where the coolant...
Sun, Jing
2007-09-17
PFC stage and trailing edge modulation for the second DC/DC converter stage can significantly reduce the ripple current and ripple voltage of the DC-link capacitor. Thus, a smaller DC-link capacitance can be used, lowering the cost and size of the AC...
TREE TRAILS Tree Trails Curriculum
TREE TRAILS Tree Trails Curriculum Tree Trails curriculum was developed by Texas A&M Forest Service Trails curriculum was developed by Texas A&M Forest Service in cooperation with Texas Urban Forestry Service Leader The curriculum is aligned to Texas Essential Knowledge and Skills (TEKS) in reading
Anacostia Tributary Trail System Paint Branch Trail
Bernstein, Joseph B.
Anacostia Tributary Trail System Paint Branch Trail Under Construction Under Construction B oulevard (M D 193) To University Boulevard Paint Branch Parkway Dickinson Avenue Princeton Avenue
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired Solar FuelTechnologyTel:FebruaryEIA's Today8TopoTowardsList Trails List
Hawkins, Brian
2014-05-31
copies of the piano roll in the upper right The player piano was retrofitted with an Arduino Uno processor that utilizes an infrared sensor to monitor the time interval between a series of perforations punched along the edge of the roll. When the piano... the Arduino and adjusts the frame-rate of the animation, accordingly. In the exhibition, I purposefully obscured the presence of these processes. The only visible suggestion of the new technologies was a computer keyboard, which was placed on the wall next...
Anding, Jenna
2008-12-09
This fact sheet describes the nutritional value and safe storage of trail mix, a commodity food. It also offers food preparation ideas....
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Complex Baseline Study, Los Alamos National Laboratory, New Mexico 2010 Response to the Impact of Social Trails Use on Cultural Resources in Technical Areas 70 and 71, Los Alamos...
Trail, Tamara; Hysmith, Larry; Harmel-Garza, Denise
2001-08-03
. The content and set up of the trail are limited only by the instructor?s imagination. Objectives The hunter skills trail may be the first ?hunting trip? for beginning hunters. It gives novices a chance to practice muzzle control, loading and unloading guns.... A. (see references). Cardboard targets also are available through retail stores. Soft decoys work well for turkey and dove scenarios. Firearms: Operational firearms can be used, but only if no live ammunition is available. Guns can be simulated...
The Patrick Elvander Taxonomy Trail
California at Santa Cruz, University of
Patrick Elvander Taxonomy Trail The Patrick Elvander Taxonomy Trail at the Arboretum at UC Santa: Taxonomy is partly the study of the naming and clas- sification of plants. For this more technical to produce a preview edition of the Manual in 1989. By establishing this Taxonomy trail as a memorial, we
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired Solar FuelTechnologyTel:FebruaryEIA's Today8TopoTowardsList Trails
Boundary element simulation of oscillating foil with leading-edge separation
Dong, Xiaoxia, S.M. Massachusetts Institute of Technology
2007-01-01
In this thesis, we develop a numerical model to account for the leading-edge separation for the boundary element simulation of the oscillating foil with potential flow assumption. Similar to the trailing-edge separation, ...
TREE TRAILS Tree Scavenger Hunt
TREE TRAILS Tree Scavenger Hunt Group _______ Try to find as many items on this list as you can. Resin is a clear or translucent substance that oozes from trees and other plants. Module 5 #12;
Sandia Energy - Experiment for Improved Modeling of Trailing-Edge
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation of Fe(II) byMultidayAlumniProjectsCyberNotLEDPhase FieldEnergy andShedding
Mean Curvature Driven Ricci Flow
Victor Tapia
2009-03-11
We obtain the evolution equations for the Riemann tensor, the Ricci tensor and the scalar curvature induced by the mean curvature flow. The evolution for the scalar curvature is similar to the Ricci flow, however, negative, rather than positive, curvature is preserved. Our results are valid in any dimension.
Spatial arrangement of trail markers and visitor involvement on a self-guided interpretive trail
Marcy, Julie Benedict
1982-01-01
be presented by asking "what constitutes an effective SGT in terms of visitor involvement with t'ne trail, leaflet suggestions, and the spacing of stakes or markers on the trail?" An effecrive program or technique is one which achieves its desired... concluded with open-ended questions on suggested improvements for the trail and leaflet. Sontag (27) states rhat there are three main ccmponents of t. rail evaluation: personal objeccive evaluation, observing visitor reaction, and questionnaires...
Curvature Capillary Migration of Microspheres
Nima Sharifi-Mood; Iris B. Liu; Kathleen J. Stebe
2015-05-11
We address the question: How does capillarity propel microspheres along curvature gradients? For a particle on a fluid interface, there are two conditions that can apply at the three phase contact line: Either the contact line adopts an equilibrium contact angle, or it can be pinned by kinetic trapping, e.g. at chemical heterogeneities, asperities or other pinning sites on the particle surface. We formulate the curvature capillary energy for both scenarios for particles smaller than the capillary length and far from any pinning boundaries. The scale and range of the distortion made by the particle are set by the particle radius; we use singular perturbation methods to find the distortions and to rigorously evaluate the associated capillary energies. For particles with equilibrium contact angles, contrary to the literature, we find that the capillary energy is negligible, with the first contribution bounded to fourth order in the product of the particle radius and the deviatoric curvature. For pinned contact lines, we find curvature capillary energies that are finite, with a functional form investigated previously by us for disks and microcylinders on curved interfaces. In experiments, we show microsphere migrate along deterministic trajectories toward regions of maximum deviatoric curvature with curvature capillary energies ranging from $6 \\times10^3 - 5 \\times 10^4~k_BT$. These data agree with the curvature capillary energy for the case of pinned contact lines. The underlying physics of this migration is a coupling of the interface deviatoric curvature with the quadrupolar mode of nanometric disturbances in the interface owing to the particle's contact line undulations. This work is an example of the major implications of nanometric roughness and contact line pinning for colloidal dynamics.
Evolution of curvature invariants and lifting integrability
Kamp, Peter H. van der
Evolution of curvature invariants and lifting integrability Elizabeth L. Mansfield and Peter H. van. These define the curvature and evolution invariants that are associated to curves moving in the given geometry. The syzygy between the curvature and evolution invariants is obtained as a zero curvature relation
Food Stories Exhibition Trail Leader's Notes
Neri, Peter
Food Stories Exhibition Trail Leader's Notes 1. Take a look at the stone fragment. Where do you a story about a celebration involving food? (No answer required) 3. This is a food hook from Papua New of grass, palm leaves and bamboo. The food hook would hang from the ceiling of the hut. Why do you think
Trail Canyon Geothermal Project | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page| Open Energy Information Serbia-EnhancingEt Al., 2013)OpenEnergyTrail Canyon Geothermal Project Jump to: navigation,
LPG odorization with an audit trail
Astala, A.A.
1995-12-01
In this article I have tried to cover a very broad subject in a very limited time while only touching on a few of the ways you could odorize LPG and have an audit trail. I would recommend that if you are interested in this type of odorizing for LPG, you contact your odorant manufacturer and two or three odorant equipment manufacturers and talk to them about what you would like and get their recommendations. By talking to more then one manufacturer you may want to incorporate the ideals of two or three manufacturers into your odorant system to have a system that meets all your needs and requirements.
Automatic Search for Differential Trails in ARX Ciphers (extended version)
International Association for Cryptologic Research (IACR)
Automatic Search for Differential Trails in ARX Ciphers (extended version) Alex Biryukov {Alex.Biryukov,Vesselin.Velichkov}@uni.lu Abstract. We propose a tool 1 for automatic search. Keywords: symmetric-key, differential trail, tools for cryptanalysis, automatic search, ARX, TEA, XTEA
R:\\Groups\\ENVIRO\\Work Requests\\2010\\Misc\\100101_Eastshore Trail...
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ENVIROWork Requests2010Misc100101Eastshore Trail100101Eastshore Trail Construction CX.docx Western Area Power Administration Sierra Nevada Region CATEGORICAL...
Mirror with thermally controlled radius of curvature
Neil, George R.; Shinn, Michelle D.
2010-06-22
A radius of curvature controlled mirror for controlling precisely the focal point of a laser beam or other light beam. The radius of curvature controlled mirror provides nearly spherical distortion of the mirror in response to differential expansion between the front and rear surfaces of the mirror. The radius of curvature controlled mirror compensates for changes in other optical components due to heating or other physical changes. The radius of curvature controlled mirror includes an arrangement for adjusting the temperature of the front surface and separately adjusting the temperature of the rear surface to control the radius of curvature. The temperature adjustment arrangements can include cooling channels within the mirror body or convection of a gas upon the surface of the mirror. A control system controls the differential expansion between the front and rear surfaces to achieve the desired radius of curvature.
Timing discriminator using leading-edge extrapolation
Gottschalk, B.
1981-07-30
A discriminator circuit to recover timing information from slow-rising pulses by means of an output trailing edge, a fixed time after the starting corner of the input pulse, which is nearly independent of risetime and threshold setting is described. This apparatus comprises means for comparing pulses with a threshold voltage; a capacitor to be charged at a certain rate when the input signal is one-third threshold voltage, and at a lower rate when the input signal is two-thirds threshold voltage; current-generating means for charging the capacitor; means for comparing voltage capacitor with a bias voltage; a flip-flop to be set when the input pulse reaches threshold voltage and reset when capacitor voltage reaches the bias voltage; and a clamping means for discharging the capacitor when the input signal returns below one-third threshold voltage.
0 50 100 150 yards White Trail (3.22 miles total)
Teskey, Robert O.
Trail (3.22 miles total) White Trail (3.22 miles total) Blue Trail (0.4 miles) Green Trail (0.14 miles.17 miles total) Middle Oconee River S. Milledge Avenue Power Line Power Line Power Line Power Line Middle Headquarters (Upper) Shade Garden (Lower) Power Line Parking #12;
Ricci Curvature of the Internet Topology
Ni, Chien-Chun; Gao, Jie; Gu, Xianfeng David; Saucan, Emil
2015-01-01
Analysis of Internet topologies has shown that the Internet topology has negative curvature, measured by Gromov's "thin triangle condition", which is tightly related to core congestion and route reliability. In this work we analyze the discrete Ricci curvature of the Internet, defined by Ollivier, Lin, etc. Ricci curvature measures whether local distances diverge or converge. It is a more local measure which allows us to understand the distribution of curvatures in the network. We show by various Internet data sets that the distribution of Ricci cuvature is spread out, suggesting the network topology to be non-homogenous. We also show that the Ricci curvature has interesting connections to both local measures such as node degree and clustering coefficient, global measures such as betweenness centrality and network connectivity, as well as auxilary attributes such as geographical distances. These observations add to the richness of geometric structures in complex network theory.
Gao, Dengliang
2013-03-01
In 3D seismic interpretation, curvature is a popular attribute that depicts the geometry of seismic reflectors and has been widely used to detect faults in the subsurface; however, it provides only part of the solutions to subsurface structure analysis. This study extends the curvature algorithm to a new curvature gradient algorithm, and integrates both algorithms for fracture detection using a 3D seismic test data set over Teapot Dome (Wyoming). In fractured reservoirs at Teapot Dome known to be formed by tectonic folding and faulting, curvature helps define the crestal portion of the reservoirs that is associated with strong seismic amplitude and high oil productivity. In contrast, curvature gradient helps better define the regional northwest-trending and the cross-regional northeast-trending lineaments that are associated with weak seismic amplitude and low oil productivity. In concert with previous reports from image logs, cores, and outcrops, the current study based on an integrated seismic curvature and curvature gradient analysis suggests that curvature might help define areas of enhanced potential to form tensile fractures, whereas curvature gradient might help define zones of enhanced potential to develop shear fractures. In certain fractured reservoirs such as at Teapot Dome where faulting and fault-related folding contribute dominantly to the formation and evolution of fractures, curvature and curvature gradient attributes can be potentially applied to differentiate fracture mode, to predict fracture intensity and orientation, to detect fracture volume and connectivity, and to model fracture networks.
Wright, Lesley Mae
2009-06-02
the effect of rotation on the heat transfer enhancement within the airfoil cooling channels. Through this experimental investigation, the heat transfer enhancement has been measured in narrow, rectangular channels with various turbulators. The present...
Persistent source influences on the trailing edge of a groundwater plume,
Office of Scientific and Technical Information (OSTI)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeeding accessusers' guide. V1.0.0. Citation Details In-Document
Persistent source influences on the trailing edge of a groundwater plume,
Office of Scientific and Technical Information (OSTI)
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LANL closes road, trails for safety reasons; flooding and erosion...
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safety reasons LANL closes road, trails for safety reasons; flooding and erosion control work under way Closure is in response to the increased fire risk and danger of flash...
16 USC 1246 - Administration and Development of National Trails...
16 USC 1246 - Administration and Development of National Trails System Jump to: navigation, search OpenEI Reference LibraryAdd to library Legal Document- StatuteStatute: 16 USC...
Trails and Dead Bodies: Directly Characterizing Extrasolar Planets...
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Trails and Dead Bodies: Directly Characterizing Extrasolar Planets with Adaptive Optics October 2, 2015 11:00AM to 12:00PM Presenter Mark Ammons, Lawrence Livermore National...
Riemannian curvature of the noncommutative 3-sphere
Joakim Arnlind; Mitsuru Wilson
2015-11-18
In order to investigate to what extent the calculus of classical (pseudo-)Riemannian manifolds can be extended to a noncommutative setting, we introduce pseudo-Riemannian calculi of modules over noncommutative algebras. In this framework, it is possible to prove an analogue of Levi-Civita's theorem, stating that there exists at most one torsion-free and metric connection for a given (metric) module, satisfying the requirements of a real metric calculus. Furthermore, the corresponding curvature operator has the same symmetry properties as the classical Riemannian curvature. As our main motivating example, we consider a pseudo-Riemannian calculus over the noncommutative 3-sphere and explicitly determine the torsion-free and metric connection, as well as the curvature operator together with its scalar curvature.
Observations of Edge Turbulence
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Edge Turbulence near the X-point of Alcator C-Mod APS-2007 (1) J.L. Terry, S.J. Zweben*, B. LaBombard, I. Cziegler, O. Grulke + , D.P. Stotler* MIT - Plasma Science and Fusion...
On the Trail of the Higgs Boson (Journal Article) | SciTech Connect
Office of Scientific and Technical Information (OSTI)
On the Trail of the Higgs Boson Citation Details In-Document Search Title: On the Trail of the Higgs Boson Authors: Peskin, Michael E. ; SLAC Publication Date: 2015-06-29 OSTI...
RESEARCH PAPER Interaction of edge influence from multiple edges: examples
Macdonald, Ellen
) in harvested forest landscapes could impair, or possibly enhance, their effectiveness. When multiple edges of cutblocks (harvested areas) and water bodies were entered into the models to predict edge influence) positive interaction, observed edge influence is greater than from either edge alone; (3) negative
Space-time Curvature of Classical Electromagnetism
R. W. M. Woodside
2004-10-08
The space-time curvature carried by electromagnetic fields is discovered and a new unification of geometry and electromagnetism is found. Curvature is invariant under charge reversal symmetry. Electromagnetic field equations are examined with De Rham co homology theory. Radiative electromagnetic fields must be exact and co exact to preclude unobserved massless topological charges. Weyl's conformal tensor, here called ``the gravitational field'', is decomposed into a divergence-free non-local piece with support everywhere and a local piece with the same support as the matter. By tuning a local gravitational field to a Maxwell field the electromagnetic field's local gravitational field is discovered. This gravitational field carries the electromagnetic field's polarization or phase information, unlike Maxwell's stress-energy tensor. The unification assumes Einstein's equations and derives Maxwell's equations from curvature assumptions. Gravity forbids magnetic monopoles! This unification is stronger than the Einstein-Maxwell equations alone, as those equations must produce the electromagnetic field's local gravitational field and not just any conformal tensor. Charged black holes are examples. Curvature of radiative null electromagnetic fields is characterized.
Energy definition for quadratic curvature gravities
Ahmet Baykal
2012-12-03
A conserved current for generic quadratic curvature gravitational models is defined, and it is shown that, at the linearized level, it corresponds to the Deser-Tekin charges. An explicit expression for the charge for new massive gravity in three dimensions is given. Some implications of the linearized equations are discussed.
Curvature in Special Base Conformal Warped Products
Fernando Dobarro; Bulent Unal
2008-04-29
We introduce the concept of a base conformal warped product of two pseudo-Riemannian manifolds. We also define a subclass of this structure called as a special base conformal warped product. After, we explicitly mention many of the relevant fields where metrics of these forms and also considerations about their curvature related properties play important rolls. Among others, we cite general relativity, extra-dimension, string and super-gravity theories as physical subjects and also the study of the spectrum of Laplace-Beltrami operators on p-forms in global analysis. Then, we give expressions for the Ricci tensor and scalar curvature of a base conformal warped product in terms of Ricci tensors and scalar curvatures of its base and fiber, respectively. Furthermore, we introduce specific identities verified by particular families of, either scalar or tensorial, nonlinear differential operators on pseudo-Riemannian manifolds. The latter allow us to obtain new interesting expressions for the Ricci tensor and scalar curvature of a special base conformal warped product and it turns out that not only the expressions but also the analytical approach used are interesting from the physical, geometrical and analytical point of view. Finally, we analyze, investigate and characterize possible solutions for the conformal and warping factors of a special base conformal warped product, which guarantee that the corresponding product is Einstein. Besides, we apply these results to a generalization of the Schwarzschild metric.
Naked singularities and the Weyl Curvature Hypothesis
Sukratu Barve; T. P. Singh
1997-05-22
We examine the growth of the Weyl curvature in two examples of naked singularity formation in spherical gravitational collapse - dust and the Vaidya spacetime. We find that the Weyl scalar diverges along outgoing radial null geodesics as they meet the naked singularity in the past. The implications of this result for the Weyl curvature hypothesis are discussed. We mention the possibility that although classical general relativity admits naked singularity solutions arising from gravitational collapse, the second law of thermodynamics could forbid their occurrence in nature. The method can also be used to compare the relative importance of initial data and that of the energy-momentum tensor in deciding the metric solution in any general case.
Curvature Dependence of Hydrophobic Hydration Dynamics
R. Gregor Weiß; Matthias Heyden; Joachim Dzubiella
2015-04-08
We investigate the curvature-dependence of water dynamics in the vicinity of hydrophobic spherical solutes using molecular dynamics simulations. For both, the lateral and perpendicular diffusivity as well as for H-bond kinetics of water in the first hydration shell, we find a non-monotonic solute-size dependence, exhibiting extrema close to the well-known structural crossover length scale for hydrophobic hydration. Additionally, we find an apparently anomalous diffusion for water moving parallel to the surface of small solutes, which, however, can be explained by topology effects. The intimate connection between solute curvature, water structure and dynamics has implications for our understanding of hydration dynamics at heterogeneous biomolecular surfaces.
Tube curvature measuring probe and method
Sokol, George J. (Scotia, NY)
1990-01-01
The present invention is directed to a probe and method for measuring the radius of curvature of a bend in a section of tubing. The probe includes a member with a pair of guide means, one located at each end of the member. A strain gauge is operatively connected to the member for detecting bending stress exrted on the member as the probe is drawn through and in engagement with the inner surface of a section of tubing having a bend. The method of the present invention includes steps utilizing a probe, like the aforementioned probe, which can be made to detect bends only in a single plane when having a fixed orientation relative the section of tubing to determine the maximum radius of curvature of the bend.
General Notion of Curvature in Catastrophe Theory Terms
Nikolov, Petko; Ruseva, Gergana
2008-01-01
We introduce a new notion of a curvature of a superconnection, different from the one obtained by a purely algebraic analogy with the curvature of a linear connection. The naturalness of this new notion of a curvature of a superconnection comes from the study of singularities of smooth sections of vector bundles (Catastrophe Theory). We demonstrate that the classical examples of obstructions to a local equivalence: exterior differential for 2-forms, Riemannian tensor, Weil tensor, curvature of a linear connection and Nijenhuis tensor can be treated in terms of one general approach. This approach, applied to the superconnection leads to a new notion of a curvature (proposed in this paper) of a superconnection.
General Notion of Curvature in Catastrophe Theory Terms
Petko Nikolov; Lora Nikolova; Gergana Ruseva
2008-02-15
We introduce a new notion of a curvature of a superconnection, different from the one obtained by a purely algebraic analogy with the curvature of a linear connection. The naturalness of this new notion of a curvature of a superconnection comes from the study of singularities of smooth sections of vector bundles (Catastrophe Theory). We demonstrate that the classical examples of obstructions to a local equivalence: exterior differential for 2-forms, Riemannian tensor, Weil tensor, curvature of a linear connection and Nijenhuis tensor can be treated in terms of one general approach. This approach, applied to the superconnection leads to a new notion of a curvature (proposed in this paper) of a superconnection.
Negative Gaussian curvature from induced metric changes
Carl D. Modes; Mark Warner
2015-06-22
We revisit the light or heat-induced changes in topography of initially flat sheets of solid that elongate or contract along patterned, in-plane director fields. For radial or azimuthal directors, negative Gaussian curvature is generated -- so-called "anti-cones". We show that azimuthal material displacements are required for the distorted state to be stretch-free and bend-minimising. The resultant shapes are smooth and aster-like and can become re-entrant in the azimuthal coordinate for large deformations. We show that care is needed when considering elastomers rather than glasses, though the former offer huge deformations.
Big Thicket National Preserve: Trails to the Future
Anderson, Luke; Allen, Chris; Elrod, Leah; Forbes, Melissa; Harbin, Hannah; Stromm, Diann
2003-01-01
stream_source_info Big_Thicket.pdf.txt stream_content_type text/plain stream_size 292407 Content-Encoding ISO-8859-1 stream_name Big_Thicket.pdf.txt Content-Type text/plain; charset=ISO-8859-1 Capstone Project... The George Bush School of Government and Public Service Texas A&M University Big Thicket National Preserve: Trails to the Future By Luke Anderson Chris Allen Leah Elrod Melissa Forbes Hannah Harbin Diann Strom Big Thicket National Preserve...
Deer Trail, Colorado: Energy Resources | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTIONRobertsdale, Alabama (UtilityInstruments IncMississippi: EnergyS A Industrias deLodgeNewDeer Trail,
LA-UR-14-22379 Trails Management at LANL
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse Bergkamp Graduate student Subtask2 J.N. Shadid,1 Hany4-22379 Trails
Evolving extrinsic curvature and the cosmological constant problem
Abraao J. S. Capistrano; Luiz A. Cabral
2015-12-09
The concept of smooth deformation of Riemannian manifolds associated with the extrinsic curvature is explained and applied to the FLRW cosmology. We show that such deformation can be derived from Einstein-Hilbert-like dynamical principle producing an observable effect in the sense of Noether. As a result, we notice on how the extrinsic curvature compensates both quantitative and qualitative difference between the cosmological constant $ \\Lambda$ and the vacuum energy $\\rho_{vac}$ obtaining the observed upper bound for the cosmological constant problem at electroweak scale. The topological characteristics of the extrinsic curvature are discussed showing that the produced extrinsic scalar curvature is an evolving dynamical quantity.
Poster No.: 169 Sulci and Curvature: Detection of the Roof
Paris-Sud XI, Université de
Poster No.: 169 Sulci and Curvature: Detection of the Roof Christophe Renault, Michel Desvignes] used the superficial trace of sulci, we detect the roof of the sulci, which presents less intersection the curvature K1 et K2 are equal. Results We have presented a method to extract roof of sulci with a sub
Global Mode Analysis of Centrifugal and Curvature Driven
Columbia University
Global Mode Analysis of Centrifugal and Curvature Driven Interchange Instabilities Benjamin Joseph Reserved #12;ABSTRACT Global Mode Analysis of Centrifugal and Curvature Driven Interchange Modes Benjamin- sure and centrifugal forces created in a laboratory magnetic dipole is presented. The mode structures
Discrete curvature and the Gauss-Bonnet theorem
Joakim Arnlind; Jens Hoppe; Gerhard Huisken
2010-01-13
For matrix analogues of embedded surfaces we define discrete curvatures and Euler characteristics, and a non-commutative Gauss--Bonnet theorem is shown to follow. We derive simple expressions for the discrete Gauss curvature in terms of matrices representing the embedding coordinates, and provide a large class of explicit examples illustrating the new notions.
Global Curvature Analysis and Segmentation Volumetric Data Sets
Rivlin, Ehud
Global Curvature Analysis and Segmentation of Volumetric Data Sets Using Trivariate B and mean curvatures of an entire volumetric data set, using a trivariate B-spline volu- metric to globally segment the images into volumetric regions that contain convex or concave “ellipticµ iso
Brown, Sally
maintenance practices for existing trails and how to locate the most optimal trail sites in the future and equestrians year round. The trail runs along the eastern bank of Baker Lake (Figure 9), traversing steep River flood plains. Field Methods In the field 72 soil samples were collected from 36 transect points
Quiver on the Edge: Consistent Scalable Edge Services
Reiter, Michael
Edge Services performne of these opertions enets from the ojet hving een miE grted to nery proxyF yther worklods enet from uiver dispersing the ompute lod ross the proxies performing opertionsD nd sving
BICEP2, the curvature perturbation and supersymmetry
Lyth, David H.
2014-11-01
The tensor fraction r ? 0.16 found by BICEP2 corresponds to a Hubble parameter H ? 1.0 × 10{sup 14} GeV during inflation. This has two implications for the (single-field) slow-roll inflation hypothesis. First, the inflaton perturbation must account for much more than 10% of the curvature perturbation ?, which barring fine-tuning means that it accounts for practically all of it. It follows that a curvaton-like mechanism for generating ? requires an alternative to slow roll such as k-inflation. Second, accepting slow-roll inflation, the excursion of the inflaton field is at least of order Planck scale. As a result, the flatness of the inflaton presumably requires a shift symmetry. I point out that if such is the case, the resulting potential is likely to have at least approximately the quadratic form suggested in 1983 by Linde, which is known to be compatible with the observed r as well as the observed spectral index n{sub s}. The shift symmetry does not require supersymmetry. Also, the big H may rule out a GUT by restoring the symmetry and producing fatal cosmic strings. The absence of a GUT would correspond to the absence of superpartners for the Standard Model particles, which indeed have yet to be found at the LHC.
Analytic torsion, vortices and positive Ricci curvature
Berman, Robert J
2010-01-01
We characterize the global maximizers of a certain non-local functional defined on the space of all positively curved metrics on an ample line bundle L over a Kahler manifold X. This functional is an adjoint version, introduced by Berndtsson, of Donaldson's L-functional and generalizes the Ding-Tian functional whose critical points are Kahler-Einstein metrics of positive Ricci curvature. Applications to (1) analytic torsions on Fano manifolds (2) Chern-Simons-Higgs vortices on tori and (3) Kahler geometry are given. In particular, proofs of conjectures of (1) Gillet-Soul\\'e and Fang (concerning the regularized determinant of Dolbeault Laplacians on the two-sphere) (2) Tarantello and (3) Aubin (concerning Moser-Trudinger type inequalities) in these three settings are obtained. New proofs of some results in Kahler geometry are also obtained, including a lower bound on Mabuchi's K-energy and the uniqueness result for Kahler-Einstein metrics on Fano manifolds of Bando-Mabuchi. This paper is a substantially extend...
Curvature-driven, One-step Assembly of Reconfigurable Smectic Liquid Crystal "Compound Eye" Lenses
Francesca Serra; Mohamed A. Gharbi; Yimin Luo; Iris B. Liu; Nathan D. Bade; Randall D. Kamien; Shu Yang; Kathleen J. Stebe
2015-05-06
Confined smectic A liquid crystals (SmA LCs) form topological defects called focal conic domains (FCDs) that focus light as gradient-index lenses. Here, we exploit surface curvature to self-assemble FCDs in a single step into a hierarchical structure (coined "flower pattern") molded by the fluid interface that is pinned at the top of a micropillar. The structure resembles the compound eyes of some invertebrates, which consist of hundreds of microlenses on a curved interface, able to focus and construct images in three dimensions. Here we demonstrate that these flowers are indeed "compound eyes" with important features which have not been demonstrated previously in the literature. The eccentric FCDs gradually change in size with radial distance from the edge of the micropillar, resulting in a variable microlens focal length that ranges from a few microns to a few tens of microns within a single "flower". We show that the microlenses can construct a composite 3D image from different depth of field. Moreover, the smectic "compound eye" can be reconfigured by heating and cooling at the LC phase transition temperature; its field of view can be manipulated by tuning the curvature of the LC interface, and the lenses are sensitive to light polarization.
On the curvature of Einstein-Hermitian surfaces
Mustafa Kalafat; Caner Koca
2014-10-19
We give a mathematical exposition of the Page metric and introduce an efficient coordinate system for it. We carefully examine the submanifolds of the underlying smooth manifold and show that it does not have positive holomorphic bisectional curvature. We also reprove that a compact complex surface together with an Einstein-Hermitian metric of positive orthogonal bisectional curvature is biholomorphically isometric to the complex projective plane with its Fubini-Study metric up to rescaling. This result relaxes the K\\"ahler condition in Berger's theorem, and the positivity condition on sectional curvature in a theorem proved by Koca.
Geometry-specific scaling of detonation parameters from front curvature
Jackson, Scott I [Los Alamos National Laboratory; Short, Mark [Los Alamos National Laboratory
2011-01-20
It has previously been asserted that classical detonation curvature theory predicts that the critical diameter and the diameter-effect curve of a cylindrical high-explosive charge should scale with twice the thickness of an analogous two-dimensional explosive slab. The varied agreement of experimental results with this expectation have led some to question the ability of curvature-based concepts to predict detonation propagation in non-ideal explosives. This study addresses such claims by showing that the expected scaling relationship (hereafter referred to d = 2w) is not consistent with curvature-based Detonation Shock Dynamics (DSD) theory.
Dynamical Analysis of Scalar Field Cosmologies with Spatial Curvature
Mateja Gosenca; Peter Coles
2015-02-13
We explore the dynamical behaviour of cosmological models involving a scalar field (with an exponential potential and a canonical kinetic term) and a matter fluid with spatial curvature included in the equations of motion. Using appropriately defined parameters to describe the evolution of the scalar field energy in this situation, we find that there are two extra fixed points that are not present in the case without curvature. We also analyse the evolution of the effective equation-of-state parameter for different initial values of the curvature.
RESEARCH GIVES EDGE TO FINDING
Angenent, Lars T.
home revisited. COVER STORY Séamus Davis and the path to faculty renewal BY BILL STEELE A look at whatSÉAMUS DAVIS AND HIS FANTASTIC MACHINE RESEARCH GIVES EDGE TO FINDING NEXT GENERATION OF FACULTY 14
Classification of Certain Compact Riemannian Manifolds with Harmonic Curvature a...
Derdzinski, Andrzej
Classification of Certain Compact Riemannian Manifolds with Harmonic Curvature a... Derdzinski and University Library provides access to digitized documents strictly for noncommercial educational, research) requires prior written permission from the Goettingen State- and University Library. Each copy of any part
Nontrivial Geometries: Bounds on the Curvature of the Universe
Laura Mersini-Houghton; Yun Wang; Pia Mukherjee; Ervin Kafexhiu
2007-05-02
Probing the geometry of the universe is one of the most important endevours in cosmology. Current observational data from the Cosmic Microwave Background anisotropy (CMB), galaxy surveys and type Ia supernovae (SNe Ia) strongly constrain the curvature of the universe to be close to zero for a universe dominated by a cosmological constant or dark energy with a constant equation of state. Here we investigate the role of cosmic priors on deriving these tight bounds on geometry, by considering a landscape motivated scenario with an oscillating curvature term. We perform a likelihood analysis of current data under such a model of non-trivial geometry and find that the uncertainties on curvature, and correspondingly on parameters of the matter and dark energy sectors, are larger. Future dark energy experiments together with CMB data from experiments like Planck could dramatically improve our ability to constrain cosmic curvature under such models enabling us to probe possible imprints of quantum gravity.
An Archaeological Survey for the Lost Pines Trails Project in Central Bastrop County, Texas
Moore, William
2015-07-29
An archaeological survey for a proposed system of hike and bike trails on the north bank of the Colorado River in central Bastrop County, Texas was performed by Brazos Valley Research Associates (BVRA) on October 2, 2007 under Texas Antiquities...
An Archaeological Survey for the Turkey Creek Trail Project in Brazos County, Texas
Moore, William
2015-07-15
An archaeological survey of the proposed Turkey Creek Trail project in central Brazos County, Texas was performed by Brazos Valley Research Associates (BVRA) in July of 2004 under Archeology Permit 3474. The state agencies associated...
Chon, Jin Hyung
2005-08-29
Urban greenway trails are emerging as potential tourist attractions in cities and are well recognized for their recreation opportunities in general. The study presented an opportunity to expand the scope of aesthetic response research...
Rohrer, Deven Michelle
2001-01-01
Research shows that road and trail crossings have negative impacts on forest streams, and that off-road vehicles are detrimental to the environment. However, little information is available concerning the effects of such vehicles on stream channels...
Quantumtheory of Wavefields in a Space of Constant Curvature
Gutzwiller, Martin C.
1953-01-01
KU ScholarWorks : Quantumtheory of Wavefields in a Space of Constant Curvature 1953 by Martin C. Gutzwiller This work has been made available by the University of Kansas Libraries Office of Scholarly Communication and Copyright. http...KU ScholarWorks : Quantumtheory of Wavefields in a Space of Constant Curvature 1953 by Martin C. Gutzwiller This work has been made available by the University of Kansas Libraries Office of Scholarly Communication and Copyright. http...
Topology of codimension-one foliations of nonnegative curvature
Bolotov, Dmitry V
2013-05-31
We show that a transversely oriented C{sup 2}-foliation of codimension one with nonnegative Ricci curvature on a closed orientable manifold is a foliation with almost no holonomy. This allows us to decompose the manifold into blocks on which this foliation has a simple structure. We also show that a manifold homeomorphic to a 5-dimensional sphere does not admit a codimension-one C{sup 2}-foliation with nonnegative sectional curvature. Bibliography: 29 titles.
Anomalous radial transport in tokamak edge plasma
Bodi, Vasudeva Raghavendra Kowsik
2010-01-01
Transport in tokamak plasma . . . . . . . . . . . . . . .Numerical simulations of tokamak plasma . . . . . . . . .of blobs in tokamak edge plasmas . . . . . . . . . . . . . .
Baer, Roi
Supplementary material to "Curvature and frontier orbital energies in density functional theory: [{ }] [{ }] #12;Supplementary material to "Curvature and frontier orbital energies in density functional theory the average curvature. This relation is Eq. (8) in the paper. #12;Supplementary material to "Curvature
Magnetic Edge States in Graphene
Gabriela Murguia
2010-08-29
Magnetic confinement in graphene has been of recent and growing interest because its potential applications in nanotechnology. In particular, the observation of the so called magnetic edge states in graphene has opened the possibility to deepen into the generation of spin currents and its applications in spintronics. We study the magnetic edge states of quasi-particles arising in graphene monolayers due to an inhomogeneous magnetic field of a magnetic barrier in the formalism of the two-dimensional massless Dirac equation. We also show how the solutions of such states in each of both triangular sublattices of the graphene are related through a supersymmetric transformation in the quantum mechanical sense.
Magnetic Edge States in Graphene
Murguia, Gabriela
2010-01-01
Magnetic confinement in graphene has been of recent and growing interest because its potential applications in nanotechnology. In particular, the observation of the so called magnetic edge states in graphene has opened the possibility to deepen into the generation of spin currents and its applications in spintronics. We study the magnetic edge states of quasi-particles arising in graphene monolayers due to an inhomogeneous magnetic field of a magnetic barrier in the formalism of the two-dimensional massless Dirac equation. We also show how the solutions of such states in each of both triangular sublattices of the graphene are related through a supersymmetric transformation in the quantum mechanical sense.
Surface Curvatures and Diffraction Profiles of Sagittaly Bent Laue Crystals
Shi, X.; Takacs, P.; Ghose, S.; Zhong, Z.; Rehak, M.L.; Kaznatcheev, K.; Dooryhee, E.
2011-05-17
The performance of a bent Laue crystal monochromator crucially depends on the sagittal and meridional bending curvatures of the crystal. To optimize the design of monochromator crystals, the surface curvatures and diffraction profiles of a set of sagittally bent Laue crystals with different aspect ratios have been studied experimentally by optical metrology and X-ray measurements. The results were confirmed with finite-element analysis using large-deformation theory. The nonlinear relationship between the curvatures necessitates an experimentally determined parameter in the theoretical modeling of the diffraction profiles. By taking into account the local stress and the aspect ratio of the sagittally bent Laue crystal, the modified analytical approach successfully predicts the rocking-curve width and the integrated reflecting power. The effect of extreme sagittal bending on the rocking curve is also discussed. To retain high reflectivity, the bending curvature should not exceed its critical value for the specified crystal geometry. Furthermore, the uniformity of the bending curvatures across the crystal surface has been examined, which suggests that the minimum crystal dimension should be approximately twice the size of the beam footprint.
Borrman, Kristina
2012-01-01
intended to strengthen dedication to established leadership.Heritage Museum. 100 The dedication ceremony was attendedEnd of the Trail's dedication ceremony. 108 The placement of
Studies of the effects of curvature on dilution jet mixing
Holdeman, J.D.; Srinivasan, Ram: Reynolds, R.S.; White, C.D. Allied-Signal Aerospace Co., Phoenix, AZ )
1992-02-01
An analytical program was conducted using both three-dimensional numerical and empirical models to investigate the effects of transition liner curvature on the mixing of jets injected into a confined crossflow. The numerical code is of the TEACH type with hybrid numerics; it uses the power-law and SIMPLER algorithms, an orthogonal curvilinear coordinate system, and an algebraic Reynolds stress turbulence model. From the results of the numerical calculations, an existing empirical model for the temperature field downstream of single and multiple rows of jets injected into a straight rectangular duct was extended to model the effects of curvature. Temperature distributions, calculated with both the numerical and empirical models, are presented to show the effects of radius of curvature and inner and outer wall injection for single and opposed rows of cool dilution jets injected into a hot mainstream flow. 27 refs.
Fusion of Edge-less and Edge-based Approaches for Horizon Line Detection
Bebis, George
the horizon line. In the edge-less approach, classification is used to obtain a confidence of horizon-ness. Moreover, we propose fusing the information about the horizon-ness and edge-ness of each pixel. Our
Anisotropic Einstein data with isotropic nonnegative scalar curvature
Bernold Fiedler; Juliette Hell; Brian Smith
2012-07-11
We construct a black hole initial data for the Einstein equations with prescribed scalar curvature, or more precisely a piece of initial data contained inside the black hole. The constraints translate into a parabolic equation, with radius as "time" variable, on a metric component u that undergoes blow up. The metric itself is regular up to and including the surface at blow up radius, which is a minimal surface. By applying equivariant bifurcation theory on a self similarly rescaled equation, we show the existence of blow up profiles that are not O(3) symmetric - or anisotropic - although the curvature was isotropically prescribed.
Defining the Free-Energy Landscape of Curvature-Inducing Proteins on Membrane Bilayers
Tourdot, Richard W; Radhakrishnan, Ravi
2015-01-01
Curvature-sensing and curvature-remodeling proteins are known to reshape cell membranes, and this remodeling event is essential for key biophysical processes such as tubulation, exocytosis, and endocytosis. Curvature-inducing proteins can act as curvature sensors as well as induce curvature in cell membranes to stabilize emergent high curvature, non-spherical, structures such as tubules, discs, and caveolae. A definitive understanding of the interplay between protein recruitment and migration, the evolution of membrane curvature, and membrane morphological transitions is emerging but remains incomplete. Here, within a continuum framework and using the machinery of Monte Carlo simulations, we introduce and compare three free-energy methods to delineate the free-energy landscape of curvature-inducing proteins on bilayer membranes. We demonstrate the utility of the Widom test-particle/field insertion methodology in computing the excess chemical potentials associated with curvature-inducing proteins on the membra...
Energy Science and Technology Software Center (OSTI)
002099IBMPC00 MM-Estimator and Adjusted Super Smoother based Simultaneous Prediction Confedenc http://nature.berkeley.edu/vulpelab/loguinov/
Marcus, F A; Fuhr, G; Monnier, A; Benkadda, S
2014-01-01
With the resonant magnetic perturbations (RMPs) consolidating as an important tool to control the transport barrier relaxation, the mechanism on how they work is still a subject to be clearly understood. In this work we investigate the equilibrium states in the presence of RMPs for a reduced MHD model using 3D electromagnetic fluid numerical code (EMEDGE3D) with a single harmonic RMP (single magnetic island chain) and multiple harmonics RMPs in cylindrical and toroidal geometry. Two different equilibrium states were found in the presence of the RMPs with different characteristics for each of the geometries used. For the cylindrical geometry in the presence of a single RMP, the equilibrium state is characterized by a strong convective radial thermal flux and the generation of a mean poloidal velocity shear. In contrast, for toroidal geometry the thermal flux is dominated by the magnetic flutter. For multiple RMPs, the high amplitude of the convective flux and poloidal rotation are basically the same in cylindr...
Posters from the edge of the universe
Trimble, V
2010-01-01
from the edge of the universe Virginia Trimble Department ofimply- ing a geocentric universe. In fact, of course the
Conformally Kähler surfaces and orthogonal holomorphic bisectional curvature
Mustafa Kalafat; Caner Koca
2015-04-06
We show that a compact complex surface which admits a conformally K\\"ahler metric g of positive orthogonal holomorphic bisectional curvature is biholomorphic to the complex projective plane. In addition, if g is a Hermitian metric which is Einstein, then the biholomorphism can be chosen to be an isometry via which g becomes a multiple of the Fubini-Study metric.
Turning Maneuvers in Sharks: Predicting Body Curvature From Axial Morphology
Long Jr., John H.
for the vertebral column in providing the passive mechanical properties of the body that control, in part, body; body curvature; morphology; vertebral column INTRODUCTION During swimming in fish-like craniates, body, University of California, Irvine, California, 92697-2525 ABSTRACT Given the diversity of vertebral morpholo
Global Segmentation and Curvature Analysis of Volumetric Data Sets Using
Rivlin, Ehud
Global Segmentation and Curvature Analysis of Volumetric Data Sets Using Trivariate B presents a method to globally segment volumetric images into regions that contain convex or concave (elliptic) iso-surfaces, planar or cylindrical (parabolic) iso-surfaces, and volumetric regions with saddle
Quantum optics with edge states Bernard Plaais
Plaēais, Bernard
Quantum optics with edge states Bernard Plaēais placais@lpa.ens.fr Gwendal Fčve Jean-Marc Berroir Genčve) #12;Aalto University, Fri. April 25th. 2014, Electron Quantum Optics with Edge States, Parts 3&4, BP Summary (quantum optics with edge states) o Electron optics principles o Single electron sources o
Dai, Yao; Liu, Meilan; Tang, Wenhua; Li, Yongming; Lian, Jiqin; Lawrence, Theodore S.; Xu, Liang
2009-11-06
Background: Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising agent for human cancer therapy, prostate cancer still remains resistant to TRAIL. Both X-linked inhibitor of apoptosis (XIAP) and nuclear factor...
Covariant Perturbation Theory (IV). Third Order in the Curvature
A. O. Barvinsky; Yu. V. Gusev; V. V. Zhytnikov; G. A. Vilkovisky
2009-11-06
The trace of the heat kernel and the one-loop effective action for the generic differential operator are calculated to third order in the background curvatures: the Riemann curvature, the commutator curvature and the potential. In the case of effective action, this is equivalent to a calculation (in the covariant form) of the one-loop vertices in all models of gravitating fields. The basis of nonlocal invariants of third order in the curvature is built, and constraints arising between these invariants in low-dimensional manifolds are obtained. All third-order form factors in the heat kernel and effective action are calculated, and several integral representations for them are obtained. In the case of effective action, this includes a specially generalized spectral representation used in applications to the expectation-value equations. The results for the heat kernel are checked by deriving all the known coefficients of the Schwinger-DeWitt expansion including $a_3$ and the cubic terms of $a_4$. The results for the effective action are checked by deriving the trace anomaly in two and four dimensions. In four dimensions, this derivation is carried out by several different techniques elucidating the mechanism by which the local anomaly emerges from the nonlocal action. In two dimensions, it is shown by a direct calculation that the series for the effective action terminates at second order in the curvature. The asymptotic behaviours of the form factors are calculated including the late-time behaviour in the heat kernel and the small-$\\Box$ behaviour in the effective action. In quantum gravity, the latter behaviour contains the effects of vacuum radiation including the Hawking effect.
Yazynin, I A; Chesnokov, Yu A; 10.1134/S0021364011150161
2011-01-01
It has been shown that the use of a bent crystal with a variable curvature radius makes it possible to reduce the fraction of dechanneled particles by an order of magnitude. This effect enables the strong reduction of the particle density at the edge of a collimator or the partition of a septum upon the multiturn extraction of a beam from a ring accelerator. In particular, the beam extraction efficiency at the U-70 synchrotron and Large Hadron Collider can be increased to 95 and 99.65%, respectively.
Sprinkle, J.K.; Hansen, W.J.
1993-02-11
In 1979, a K-edge densitometer (KED) was installed by the Safeguards Assay group from Los Alamos National Laboratory in the PNC reprocessing plant at Tokai-mura, Japan. It uses an active nondestructive assay technique, KED, to measure the plutonium concentration of the product solution. The measurement uncertainty of an assay depends on the count time chosen, but can be 0.5% or better. The computer hardware and software were upgraded in 1992. This manual describes the operation of the instrument, with an emphasis on the user interface to the software.
EDG Fuels | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX E LISTStar2-0057-EA Jump to:of the NationalDynetek Europe GmbHED F Man HoldingsEDG Fuels
THE EFFECTS OF A RESTRICTIVE MANAGEMENT APPROACH ON THE CHILKOOT TRAIL VISITOR POPULATION
Committee Member: Tom Elliot Visitor and Wilderness Management Research Parks Canada - Yukon Field Unit Date would also like to thank Dr. Peter Williams and Tom Elliot for their thoughtful and constructive reviews to acknowledge previous Chilkoot Trail researchers Siobhan Jackson and Tom Elliot; their work provided the basis
Engineering students at Colorado State University blaze trails with their studies, impacting
Collett Jr., Jeffrey L.
Engineering students at Colorado State University blaze trails with their studies, impacting Human.engr.colostate.edu/academics/ student_services/. The engineering faculty at Colorado State are recognized for their dedication impact and our faculty bring that knowledge into the classroom. The Engineering Academic Village, a new
Discovering Structured Event Logs from Unstructured Audit Trails for Workflow Mining
Discovering Structured Event Logs from Unstructured Audit Trails for Workflow Mining Liqiang Geng1@ucalgary.ca, {larry.korba, hongyu.liu, yunlin.wang}@nrc.gc.ca Abstract. Workflow mining aims to find graph workflow mining techniques mainly deal with well-structured and -symbolized event logs. In most real
Meteor Trail Echo Rejection in Atmospheric Phased Array Radars Using Adaptive Sidelobe Cancellation
Sato, Toru
of power (NC-DCMP), which balances the capability of canceling the clutter and the robustness of beam February 2014, in final form 21 May 2014) ABSTRACT Strong meteor trail echoes are interferences in the wind of the signal-to-noise ratio (SNR) and inaccurate wind estimates for weak atmospheric echoes. This paper
Imaging of lithium pellet ablation trails and measurement of g profiles in TFTR
Garnier, Darren T.
Imaging of lithium pellet ablation trails and measurement of g profiles in TFTR J. L. Terry, E. S March 1992) Video images with 2 ps exposures of the Li+ emission in Li pellet ablation clouds have been obtained in a variety of Tokamak Fusion Test Reactor tokamak discharges. The pellet clouds are viewed from
Proc. of Internet Society INET `99 Electronic Commerce with Verifiable Audit Trails
Peha, Jon M.
Proc. of Internet Society INET `99 Electronic Commerce with Verifiable Audit Trails Jon M. Peha://users.ece.cmu.edu/~peha/etrans.html 1 of 16 11/8/2013 7:28 PM #12;· Section 5: Summary · References Section 1: Introduction The Internet. This limitation first became a serious problem in the telecommunications context due to the Internet pornography
Lyapunov exponents and phase diagrams reveal multi-factorial control over TRAIL-induced apoptosis
Lyapunov exponents and phase diagrams reveal multi-factorial control over TRAIL-induced apoptosis). Here, we investigate factors controlling type I versus II phenotypes by performing Lyapunov exponent-or-none control over activation of effector caspases. Thus, phase diagrams derived from Lyapunov exponent analysis
Following the invisible trail: kinematic analysis of mate-tracking in the copepod
Yen, Jeannette
Following the invisible trail: kinematic analysis of mate-tracking in the copepod Temora analysis indicates both sequential and simultaneous taxis mechanisms are used byTemora to follow the odour movements during tracking. Kinematic analysis is a powerful tool that has been used to investigate sensory
Graphene as a quantum surface with curvature-strain preserving dynamics
M. V. Karasev
2010-11-16
We discuss how the curvature and the strain density of the atomic lattice generate the quantization of graphene sheets as well as the dynamics of geometric quasiparticles propagating along the constant curvature/strain levels. The internal kinetic momentum of Riemannian oriented surface (a vector field preserving the Gaussian curvature and the area) is determined.
Facet bending in the driven crystalline curvature flow in the plane
Ikegami, Takashi
Facet bending in the driven crystalline curvature flow in the plane Yoshikazu Giga1 , Piotr Rybka2, then they begin to bend. Key words: singular energies, bending of facets, driven curvature flow, variational prin- clidean curvature. In this paper we are interested in the case when is not C1, for example
PROBING CURVATURE EFFECTS IN THE FERMI GRB 110920
Shenoy, A.; Maximon, L. C.; Dhuga, K. S.; Parke, W. C.; Maclachlan, G. A.; Eskandarian, Ali [Department of Physics, The George Washington University, Washington, DC 20052 (United States); Sonbas, E. [Department of Physics, University of Adiyaman, 02040 Adiyaman (Turkey); Dermer, C. [Space Science Division, Code 7653, Naval Research Laboratory, Washington, DC 20375 (United States); Bhat, P. N. [CSPAR, University of Alabama in Huntsville, Huntsville, AL 35805 (United States); Hakkila, J. [Department of Physics and Astronomy, College of Charleston, Charleston, SC 29424 (United States); Ukwatta, T. N., E-mail: ashwinsp469@gmail.com [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)
2013-11-20
Curvature effects in gamma-ray bursts (GRBs) have long been a source of considerable interest. In a collimated relativistic GRB jet, photons that are off-axis relative to the observer arrive at later times than on-axis photons and are also expected to be spectrally softer. In this work, we invoke a relatively simple kinematic two-shell collision model for a uniform jet profile and compare its predictions to GRB prompt-emission data for observations that have been attributed to curvature effects such as the peak-flux-peak-frequency relation, i.e., the relation between the ?F{sub ?} flux and the spectral peak, E{sub pk} in the decay phase of a GRB pulse, and spectral lags. In addition, we explore the behavior of pulse widths with energy. We present the case of the single-pulse Fermi GRB 110920 as a test for the predictions of the model against observations.
Higher curvature counter terms cause the bounce in loop cosmology
Helling, Robert C
2009-01-01
In the loop approach to the quantisation of gravity, one uses a Hilbert space which is too singular for some operators to be realised as derivatives. This is usually addressed by instead using finite difference operators at the Planck scale, a process known as ``polymerisation''. In the symmetry reduced example of loop cosmology, we study an ambiguity in the regularisation which we relate to the ambiguity of fixing the coefficients of infinitely many higher curvature counter terms augmenting the Einstein-Hilbert action. Thus the situation is comparable to he one in a naive perturbative treatment of quantum gravity with a cut-off where the necessary presence of infinitely many higher derivative terms compromises predictability. As a by-product, we demonstrate in an appendix that it is possible to have higher curvature actions for gravity which still lead to first order equations of motion like in the Friedmann case.
Higher curvature counter terms cause the bounce in loop cosmology
Robert C. Helling
2009-12-17
In the loop approach to the quantisation of gravity, one uses a Hilbert space which is too singular for some operators to be realised as derivatives. This is usually addressed by instead using finite difference operators at the Planck scale, a process known as ``polymerisation''. In the symmetry reduced example of loop cosmology, we study an ambiguity in the regularisation which we relate to the ambiguity of fixing the coefficients of infinitely many higher curvature counter terms augmenting the Einstein-Hilbert action. Thus the situation is comparable to he one in a naive perturbative treatment of quantum gravity with a cut-off where the necessary presence of infinitely many higher derivative terms compromises predictability. As a by-product, we demonstrate in an appendix that it is possible to have higher curvature actions for gravity which still lead to first order equations of motion like in the Friedmann case.
Curvature effects on carbon nanomaterials: Exohedral versus endhohedral supercapacitors
Huang, J; Sumpter, B. G.; Meunier, V.; Yushin, G.; Portet, C.; Gogotsi, Y.
2011-01-31
Capacitive energy storage mechanisms in nanoporous carbon supercapacitors hinge on endohedral interactions in carbon materials with macro-, meso-, and micropores that have negative surface curvature. In this article, we show that because of the positive curvature found in zero-dimensional carbon onions or one-dimensional carbon nanotube arrays, exohedral interactions cause the normalized capacitance to increase with decreasing particle size or tube diameter, in sharp contrast to the behavior of nanoporous carbon materials. This finding is in good agreement with the trend of recent experimental data. Our analysis suggests that electrical energy storage can be improved by exploiting the highly curved surfaces of carbon nanotube arrays with diameters on the order of 1 nm.
Curvature effects in carbon nanomaterials: Exohedral versus endohedral supercapacitors
Huang, Jingsong; Sumpter, Bobby G; Meunier, Vincent; Gogotsi, Yury G.; Yushin, Gleb; Portet, Cristelle
2010-01-01
Capacitive energy storage mechanisms in nanoporous carbon supercapacitors hinge on endohedral interactions in carbon materials with macro-, meso-, and micropores that have negative surface curvature. In this article, we show that because of the positive curvature found in zero-dimensional carbon onions or one-dimensional carbon nanotube arrays, exohedral interactions cause the normalized capacitance to increase with decreasing particle size or tube diameter, in sharp contrast to the behavior of nanoporous carbon materials. This finding is in good agreement with the trend of recent experimental data. Our analysis suggests that electrical energy storage can be improved by exploiting the highly curved surfaces of carbon nanotube arrays with diameters on the order of 1 nm.
Numerical computation of constant mean curvature surfaces using finite elements
Jan Metzger
2004-08-18
This paper presents a method for computing two-dimensional constant mean curvature surfaces. The method in question uses the variational aspect of the problem to implement an efficient algorithm. In principle it is a flow like method in that it is linked to the gradient flow for the area functional, which gives reliable convergence properties. In the background a preconditioned conjugate gradient method works, that gives the speed of a direct elliptic multigrid method.
On the curvature of dustlanes in galactic bars
Comeron, Sebastien; Knapen, Johan H; Beckman, John E
2009-01-01
We test the theoretical prediction that the straightest dust lanes in bars are found in strongly barred galaxies, or more specifically, that the degree of curvature of the dust lanes is inversely proportional to the strength of the bar. The test used archival images of barred galaxies for which a reliable non-axisymmetric torque parameter (Qb) and the radius at which Qb has been measured (r(Qb)) have been published in the literature. Our results confirm the theoretical prediction but show a large spread that cannot be accounted for by measurement errors. We simulate 238 galaxies with different bar and bulge parameters in order to investigate the origin of the spread in the dust lane curvature versus Qb relation. From these simulations, we conclude that the spread is greatly reduced when describing the bar strength as a linear combination of the bar parameters Qb and the quotient of the major and minor axis of the bar, a/b. Thus we conclude that the dust lane curvature is predominantly determined by the parame...
Simons, Jack
of a 3D structure [11,12]: the edge (surface) energy accounting for the energy cost to create an edge for the energy cost to deform an edge (surface) defines the edge (surface) mechanical stability. First-principles calculations showed that chemically the armchair edge is more stable with a lower energy, while the zigzag edge
Meisam Asgari; Aisa Biria
2015-04-05
Lipid-bilayers are the fundamental constituents of the walls of most living cells and lipid vesicles, giving them shape and compartment. The formation and growing of pores in a lipid bilayer have attracted considerable attention from an energetic point of view in recent years. Such pores permit targeted delivery of drugs and genes to the cell, and regulate the concentration of various molecules within the cell. The formation of such pores is caused by various reasons such as changes in cell environment, mechanical stress or thermal fluctuations. Understanding the energy and elastic behaviour of a lipid-bilayer edge is crucial for controlling the formation and growth of such pores. In the present work, the interactions in the molecular level are used to obtain the free energy of the edge of an open lipid bilayer. The resulted free-energy density includes terms associated with flexural and torsional energies of the edge, in addition to a line-tension contribution. The line tension, elastic moduli, and spontaneous normal and geodesic curvatures of the edge are obtained as functions of molecular distribution, molecular dimensions, cutoff distance, and the interaction strength. These parameters are further analyzed by implementing a soft-core interaction potential in the microphysical model. The dependence of the elastic free-energy of the edge to the size of the pore is reinvestigated through an illustrative example, and the results are found to be in agreement with the previous observations.
Closeness to spheres of hypersurfaces with normal curvature bounded below
Borisenko, A A; Drach, K D
2013-11-30
For a Riemannian manifold M{sup n+1} and a compact domain ?? M{sup n+1} bounded by a hypersurface ?? with normal curvature bounded below, estimates are obtained in terms of the distance from O to ?? for the angle between the geodesic line joining a fixed interior point O in ? to a point on ?? and the outward normal to the surface. Estimates for the width of a spherical shell containing such a hypersurface are also presented. Bibliography: 9 titles.
Statistical anisotropy of the curvature perturbation from vector field perturbations
Dimopoulos, Konstantinos; Karciauskas, Mindaugas; Lyth, David H.; Rodriguez, Yeinzon E-mail: m.karciauskas@lancaster.ac.uk E-mail: yeinzon.rodriguez@uan.edu.co
2009-05-15
The {delta}N formula for the primordial curvature perturbation {zeta} is extended to include vector as well as scalar fields. Formulas for the tree-level contributions to the spectrum and bispectrum of {zeta} are given, exhibiting statistical anisotropy. The one-loop contribution to the spectrum of {zeta} is also worked out. We then consider the generation of vector field perturbations from the vacuum, including the longitudinal component that will be present if there is no gauge invariance. Finally, the {delta}N formula is applied to the vector curvaton and vector inflation models with the tensor perturbation also evaluated in the latter case.
Curvature and geometric modules of noncommutative spheres and tori
Arnlind, Joakim
2014-04-15
When considered as submanifolds of Euclidean space, the Riemannian geometry of the round sphere and the Clifford torus may be formulated in terms of Poisson algebraic expressions involving the embedding coordinates, and a central object is the projection operator, projecting tangent vectors in the ambient space onto the tangent space of the submanifold. In this note, we point out that there exist noncommutative analogues of these projection operators, which implies a very natural definition of noncommutative tangent spaces as particular projective modules. These modules carry an induced connection from Euclidean space, and we compute its scalar curvature.
Curvature and geometric modules of noncommutative spheres and tori
Joakim Arnlind
2013-12-19
When considered as submanifolds of Euclidean space, the Riemannian geometry of the round sphere and the Clifford torus may be formulated in terms of Poisson algebraic expressions involving the embedding coordinates, and a central object is the projection operator, projecting tangent vectors in the ambient space onto the tangent space of the submanifold. In this note, we point out that there exist noncommutative analogues of these projection operators, which implies a very natural definition of noncommutative tangent spaces as particular projective modules. These modules carry an induced connection from Euclidean space, and we compute its scalar curvature.
Direct and alignment-insensitive measurement of cantilever curvature
Hermans, Rodolfo I.; Aeppli, Gabriel; Bailey, Joe M.
2013-07-15
We analytically derive and experimentally demonstrate a method for the simultaneous measurement of deflection for large arrays of cantilevers. The Fresnel diffraction patterns of a cantilever independently reveal tilt, curvature, cubic, and higher order bending of the cantilever. It provides a calibrated absolute measurement of the polynomial coefficients describing the cantilever shape, without careful alignment and could be applied to several cantilevers simultaneously with no added complexity. We show that the method is easily implemented, works in both liquid media and in air, for a broad range of displacements and is especially suited to the requirements for multi-marker biosensors.
Curvature effect on tearing modes in presence of neoclassical friction
Maget, Patrick; Mellet, Nicolas; Meshcheriakov, Dmytro; Garbet, Xavier [CEA, IRFM, F-13108 Saint Paul-lez-Durance (France)] [CEA, IRFM, F-13108 Saint Paul-lez-Durance (France); Lütjens, Hinrich [Centre de Physique Théorique, Ecole Polytechnique, CNRS (France)] [Centre de Physique Théorique, Ecole Polytechnique, CNRS (France)
2013-11-15
Neoclassical physics (here associated to the poloidal variation of the magnetic field strength along field lines in a tokamak) is well known for driving self-generated plasma current and nonlinear magnetic islands associated to it in high performance, ITER relevant plasma discharges. It is demonstrated that the neoclassical friction between a magnetic perturbation and plasma flow already impacts magnetic islands in the linear regime, by inducing a weakening of curvature stabilization for tearing modes. This conclusion holds in particular for regimes where convection is influencing the pressure dynamics, as shown using a simple analytical model and confirmed in full Magneto-Hydro-Dynamics simulations.
The Hidden K-edge Signal in K-edge Imaging
Bateman, Christopher J; de Ruiter, Niels J A; Butler, Anthony P; Butler, Philip H; Renaud, Peter F
2015-01-01
K-edge imaging is commonly used for viewing contrast pharmaceuticals in a variety of multi-energy x-ray imaging techniques, ranging from dual-energy and spectral computed tomography to fluoroscopy. When looking for the K-edge signal of a specific contrast, by taking measurements either side of the K-edge, it is found that the K-edge is not always observable for low concentrations. We have also observed that the ability to see the K-edge is unit dependent - a K-edge that is not observable in computed tomography (CT) reconstructed linear attenuation units can often be made visible by converting to Hounsfield units. This paper presents an investigation of this K-edge hiding phenomenon. We conclude that if a multi-energy x-ray measurement of any K-edge material contains a signal of any other material, then there will be a positive concentration of that K-edge material below which its K-edge cannot be observed without extracting the K-edge signal through means of basis decomposition. Mathematical descriptions of t...
Role of the mean curvature in the geometry of magnetic confinement configurations
Skovoroda, A. A. [Russian Research Centre Kurchatov Institute (Russian Federation); Taimanov, I. A. [Russian Academy of Sciences, Sobolev Institute of Mathematics, Siberian Branch (Russian Federation)
2010-09-15
Examples are presented of how the geometric notion of the mean curvature is applied to the vector of a general magnetic field and to magnetic surfaces. It is shown that the mean curvature is related to the variation of the absolute value of the magnetic field along its lines. Magnetic surfaces of constant mean curvature are optimum for plasma confinement in multimirror open confinement systems and rippled tori.
A comparison of edge detection operators
Lee, Juck Sik
1986-01-01
, (a. IS) where I(z, y) is the image, and & is the convolution operator. By the derivative rule for convolutions, f(z, y) = G(x, y) ~ V I(z, y) = V G(x, y) w I(x, y). (2. 16) V'zG(z, y) is given by the following expression 8 G(z, y) 8 G(z, y) '7'G... Operator 5 7 10 ll III DISCUSSION ON EDGE DETECTION OPERATORS 16 A. Transfer Function B. Filtering C. Differentiation D. Zero Crossing E. Thresholding F. Edge Length and Displacement 17 19 20 22 24 25 IV EDGE DETECTION PERFORMANCE...
Thresholds : landscape, city, and building edges
Frontiero, Wendy Ellen
1986-01-01
This thesis is a study of edges: the three-dimensional transitions between one kind of place or activity and another. We consider several scales of architecture where these transitions occur in an urban context, using the ...
Associate Research Physicist (Plasma Edge Research) | Princeton...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
boundary, has enabled high-resolution of the main-ion temperature, density and toroidal velocity. The primary research objective is to use the new main-ions in the edge of the...
Revealing Burlington : Vermont architecture on the edge
Gates, Jeremy M., 1975-
2005-01-01
This project explores building in the most urban environment of a state that identifies with its ruralness. The site, located at the top of a steep bluff in Burlington at the edge between the city's downtown core and its ...
Unbalanced edge modes and topological phase transition in gated...
Office of Scientific and Technical Information (OSTI)
Unbalanced edge modes and topological phase transition in gated trilayer graphene Prev Next Title: Unbalanced edge modes and topological phase transition in gated trilayer...
SoCal Edge: Accelerating Investments in Innovative Building Technologi...
Office of Environmental Management (EM)
SoCal Edge: Accelerating Investments in Innovative Building Technologies SoCal Edge: Accelerating Investments in Innovative Building Technologies October 26, 2015 - 2:53pm Addthis...
Positive curvature property for some hypoelliptic heat kernels
Qian, Bin
2010-01-01
In this note, we look at some hypoelliptic operators arising from nilpotent rank 2 Lie algebras. In particular, we concentrate on the diffusion generated by three Brownian motions and their three L\\'evy areas, which is the simplest extension of the Laplacian on the Heisenberg group $\\mathbb{H}$. In order to study contraction properties of the heat kernel, we show that, as in the case of the Heisenberg group, the restriction of the sub-Laplace operator acting on radial functions (which are defined in some precise way in the core of the paper) satisfies a non negative Ricci curvature condition (more precisely a $CD(0, \\infty)$ inequality), whereas the operator itself does not satisfy any $CD(r,\\infty)$ inequality. From this we may deduce some useful, sharp gradient bounds for the associated heat kernel.
Jacobi Fields on Statistical Manifolds of Negative Curvature
Carlo Cafaro; S. A. Ali
2007-02-14
Two entropic dynamical models are considered. The geometric structure of the statistical manifolds underlying these models is studied. It is found that in both cases, the resulting metric manifolds are negatively curved. Moreover, the geodesics on each manifold are described by hyperbolic trajectories. A detailed analysis based on the Jacobi equation for geodesic spread is used to show that the hyperbolicity of the manifolds leads to chaotic exponential instability. A comparison between the two models leads to a relation among statistical curvature, stability of geodesics and relative entropy-like quantities. Finally, the Jacobi vector field intensity and the entropy-like quantity are suggested as possible indicators of chaoticity in the ED models due to their similarity to the conventional chaos indicators based on the Riemannian geometric approach and the Zurek-Paz criterion of linear entropy growth, respectively.
On the Possibility of Anisotropic Curvature in Cosmology
Tomi S. Koivisto; David F. Mota; Miguel Quartin; Tom G. Zlosnik
2010-11-22
In addition to shear and vorticity a homogeneous background may also exhibit anisotropic curvature. Here a class of spacetimes is shown to exist where the anisotropy is solely of the latter type, and the shear-free condition is supported by a canonical, massless 2-form field. Such spacetimes possess a preferred direction in the sky and at the same time a CMB which is isotropic at the background level. A distortion of the luminosity distances is derived and used to test the model against the CMB and supernovae (using the Union catalog), and it is concluded that the latter exhibit a higher-than-expected dependence on angular position. It is shown that future surveys could detect a possible preferred direction by observing ~ 20 / (\\Omega_{k0}^2) supernovae over the whole sky.
Implications on the cosmic coincidence by a dynamical extrinsic curvature
A. J. S Capistrano; L. A. Cabral
2015-12-09
In this work, we apply the smooth deformation concept in order to obtain a modification of Friedmann equations. It is shown that the cosmic coincidence can be at least alleviated using the dynamical properties of the extrinsic curvature. We investigate the transition from nucleosynthesis to the coincidence era obtaining a very small variation of the ratio $r=\\frac{\\rho_{m}}{\\rho_{ext}}$, that compares the matter energy density to extrinsic energy density, compatible with the known behavior of the deceleration parameter. We also show that the calculated "equivalence" redshift matches the transition redshift from a deceleration to accelerated phase and the coincidence ceases to be. The dynamics on $r$ is also studied based on Hubble parameter observations as the latest Baryons Acoustic Oscillations/Cosmic Microwave Background Radiation (BAO/CMBR) + SNIa.
De Santo, Robert James William
1972-01-01
Santo, Jr. , B. S. , United States Air Force Academy Directed by: Dr. Balusu M. Rao A method is developed to predict the changes in the aerodynamic forces and moments on an aircraft as it passes through the trailing vortex system of another aircraft.... The method is based on a liftinq surface theory developed by Jones and Rao and on a modified lifting line theory developed by Glauert. The aerodynamic forces and moments, in the horizontal and vertical planes, are computed using the De- Havilland Beaver...
Los Alamos science sleuth on the trail of a martian mystery
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse BergkampCentermillion to local UnitedtoHOPE forceramics for reactorTrail
Curvature-based energy for simulation and variational modeling Denis Zorin
Mohri, Mehryar
Curvature-based energy for simulation and variational modeling Denis Zorin New York University 719 Broadway, 12th floor New York, New York, 10012 dzorin@mrl.nyu.edu Abstract Curvature-based energy to their simplicity and low computational cost. Both types of approaches have found applications in geometric modeling
Caselles, Vicent
Crystalline mean curvature flow of convex sets G. Bellettini # , V. Caselles + , A. Chambolle # , M. Novaga Ā§ 29th October 2004 Abstract We prove a local existence and uniqueness result of crystalline mean a compact convex set is unique. Key words: crystalline mean curvature, #Āregular flows, flat flows, convex
Curvature-Mediated Interactions Between Membrane Proteins K. S. Kim,* John Neu,#
Oster, George
their pairwise repulsions. GLOSSARY a Annulus surrounding a protein a Mean curvature bending modulus b Gaussian curvature bending modulus a1 Dipole coefficient c Projection of S onto the base plane C Protein and by the membrane's elastic properties. In this paper, we examine the deformation field generated by proteins
Unknown
2011-09-05
Dataset includes 23 GPS files that describe fishing trips made by Dominican fishers to fish aggregating devices. Files are in RData file format.
Unknown
2011-09-05
Adults associate their childhood with playing outdoors, often in natural settings. This type of free play is valuable to child development. Children tend to use outdoor play areas in physically active ways, and time spent outdoors relates...
Unknown
2011-09-05
As discussed in the World Report on Disabilities, disasters and war not only cause disabilities but also create additional physical or communicational barriers in the environment. For example, fallen trees, torn up roads, or collapsed buildings make negotiating... rehabilitation can be provided even in developing countries. Although rehabilitation is usually considered for individuals with physical disabilities, individuals with intellectual disabilities are may also require rehabilitation services. Some estimates (e...
Edge states in polariton honeycomb lattices
Milicevic, M; Andreakou, P; Carusotto, I; Jacqmin, T; Galopin, E; Lemaītre, A; Gratiet, L Le; Sagnes, I; Bloch, J; Amo, A
2015-01-01
The experimental study of edge states in atomically-thin layered materials remains a challenge due to the difficult control of the geometry of the sample terminations, the stability of dangling bonds and the need to measure local properties. In the case of graphene, localised edge modes have been predicted in zig-zag and bearded edges, characterised by flat dispersions connecting the Dirac points. Polaritons in semiconductor microcavities have recently emerged as an extraordinary photonic platform to emulate 1D and 2D Hamiltonians, allowing the direct visualization of the wavefunctions in both real- and momentum-space as well as of the energy dispersion of eigenstates via photoluminescence experiments. Here we report on the observation of edge states in a honeycomb lattice of coupled micropillars. The lowest two bands of this structure arise from the coupling of the lowest energy modes of the micropillars, and emulate the {\\pi} and {\\pi}* bands of graphene. We show the momentum space dispersion of the edge st...
Practical Edge Finding with a Robust Estimator Margaret M. Fleck
Fleck, Margaret M.
classified pixels. The algorithm is made as fast as a MarrHildreth edge finder by restructuring the esti mator textured regions (figure 1), at the same speed as a MarrHildreth edge finder. A scalar image can; Figure 1: A textured image, the output of a Marr Hildreth edge finder (top), edges and smoothed values
Huynh, Long Quang
1994-01-01
An empirical model has been developed to predict the mean-velocity profile of a turbulent boundary layer under the influence of surface curvature. The model proposed is able to determine the profiles for both a convex and concave curvature...
Linear response to long wavelength fluctuations using curvature simulations
Tobias Baldauf; Uro Seljak; Leonardo Senatore; Matias Zaldarriaga
2015-11-04
We study the local response to long wavelength fluctuations in cosmological $N$-body simulations, focusing on the matter and halo power spectra, halo abundance and non-linear transformations of the density field. The long wavelength mode is implemented using an effective curved cosmology and a mapping of time and distances. The method provides an alternative, most probably more precise, way to measure the isotropic halo biases. Limiting ourselves to the linear case, we find generally good agreement between the biases obtained from the curvature method and the traditional power spectrum method at the level of a few percent. We also study the response of halo counts to changes in the variance of the field and find that the slope of the relation between the responses to density and variance differs from the naive derivation assuming a universal mass function by 18%. This has implications for measurements of the amplitude of local non-Gaussianity using scale dependent bias. We also analyze the halo power spectrum and halo-dark matter cross-spectrum response to long wavelength fluctuations and derive second order halo bias from it, as well as the super-sample variance contribution to the galaxy power spectrum covariance matrix.
Curvature fluctuations and the Lyapunov exponent at melting
Mehra, V.; Ramaswamy, R. [School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067 (India)] [School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067 (India)
1997-09-01
We calculate the maximal Lyapunov exponent in constant-energy molecular-dynamics simulations at the melting transition for finite clusters of 6{endash}13 particles (model rare-gas and metallic systems) as well as for bulk rare-gas solids. For clusters, the Lyapunov exponent generally varies linearly with the total energy, but the {ital slope} changes sharply at the melting transition. In the bulk system, melting corresponds to a jump in the Lyapunov exponent, and this corresponds to a singularity in the variance of the curvature of the potential-energy surface. In these systems there are two mechanisms of chaos{emdash}local instability and parametric instability. We calculate the contribution of the parametric instability toward the chaoticity of these systems using a recently proposed formalism. The contribution of parametric instability is a continuous function of energy in small clusters but not in the bulk where the melting corresponds to a decrease in this quantity. This implies that the melting in small clusters does not lead to enhanced local instability. {copyright} {ital 1997} {ital The American Physical Society}
PICK-UP ION DISTRIBUTIONS AND THEIR INFLUENCE ON ENERGETIC NEUTRAL ATOM SPECTRAL CURVATURE
Livadiotis, G.; McComas, D. J.; Randol, B. M.; Schwadron, N. A.; Dayeh, M. A.; Funsten, H. O.; Moebius, E. S.; Zank, G. P.; Frisch, P. C.
2012-05-20
This paper focuses on the analysis and significance of the spectral curvature of energetic neutral atoms (ENAs) detected by the Interstellar Boundary Explorer. The flux versus energy spectrum is analytically expressed in terms of the source proton distributions, namely: (1) the solar wind kappa distribution of protons and (2) the coexisting filled spherical shell distribution of pick-up ions (PUIs). The influence of PUIs on the spectral index and curvature is modeled and investigated in detail. It is analytically shown that (1) the PUI speed upper limit is restricted by the Earthward PUI velocity vector, (2) the PUI distribution causes a positive spectral curvature, and (3) the exact expressions of the spectral index and curvature can be used to extract information about the governing parameters of the parent proton distributions. The sky maps of the spectral curvature reveal a possible band-like configuration of positive spectral curvature that is missing in the original flux sky maps. This band can be roughly separated into the north/south polar regions and two ecliptic meridional 'columns' located around the ecliptic longitudes {approx}5 Degree-Sign and {approx}150 Degree-Sign . The geometric locus between the two cones with noseward axis, and apertures {approx}60 Degree-Sign and {approx}120 Degree-Sign , configures the band-like region of (1) the positive curvature and (2) the maximum values of PUI distribution. Indeed, the observed curvature band is highly correlated with PUI distributions, and is possibly caused by the influence of PUIs on bending the spectrum from linear (log-log scale) to concave upward, thus increasing its spectral curvature.
Topology of codimension-one foliations of nonnegative curvature. II
Bolotov, D V
2014-10-31
We prove that a 3-connected closed manifold M of dimension n?5 does not admit a codimension-one C{sup 2}-foliation of nonnegative curvature. In particular, this gives a complete answer to a question of Stuck on the existence of codimension-one foliations of nonnegative curvature on spheres. We also consider codimension-one C{sup 2}-foliations of nonnegative Ricci curvature on a closed manifold M with leaves having finitely generated fundamental group, and show that such a foliation is flat if and only if M is a K(?,1)-manifold. Bibliography: 13 titles.
Afonin, A G; Bulgakov, M K; Chesnokov, Yu A; Chirkov, P N; Lobanova, E V; Lobanov, I S; Lunkov, A N; Maisheev, V A; Poluektov, I V; Sandomirskiy, Yu E; Yazynin, I A
2012-01-01
Recently it was proposed to apply a bent single crystal with decreasing curvature instead of uniform bending for improvement of extraction and collimation of a circulating beam in particle accelerators. In the given paper created crystal devices with a variable curvature, realizing this idea are described. Results of measurement of curvature along a crystal plate are informed. It is shown, that with the help of the developed devices it is possible to carry out also high energy beam focusing. The mathematical description of this process is proposed.
Curvature aided long range propagation of short laser pulses in the atmosphere
Yedierler, Burak [Department of Physics, Middle East Technical University, 06800 Ankara (Turkey)
2013-03-15
The pre-filamentation regime of propagation of a short and intense laser pulse in the atmosphere is considered. Spatiotemporal self-focusing dynamics of the laser beam are investigated by calculating the coupled differential equations for spot size, pulse length, phase, curvature, and chirp functions of a Gaussian laser pulse via a variational technique. The effect of initial curvature parameter on the propagation of the laser pulse is taken into consideration. A method relying on the adjustment of the initial curvature parameter can expand the filamentation distance of a laser beam of given power and chirp is proposed.
Leading Edge Bacterial Genomics and Pathogen Evolution
Mekalanos, John
Leading Edge Review Bacterial Genomics and Pathogen Evolution David M. Raskin,1 Rekha Seshadri,2 Medical School, Boston, MA 02115, USA 2 The Institute for Genomic Research, 9712 Medical Center Drive.02.002 The availability of hundreds of bacterial genome sequences has altered the study of bacte- rial pathogenesis
Strip edge cracking simulation in cold rolling
Hubert, C.; Dubar, L.; Dubar, M.; Dubois, A.
2011-01-17
This research work focuses on a specific defect which occurs during cold rolling of steel strips: edge-serration. Investigations on the industrial processes have led to the conclusion that this defect is the result of the edge-trimming and cold rolling sequences. The aim of this research work is to analyze the effect of the cutting process and the cold rolling on cracks occurrence, especially on strip edges.This study is performed using an experimental testing stand called Upsetting Rolling Test (URT). It allows to reproduce cold rolling contact parameters such as forward slip, reduction ratio and friction coefficients. Specimens sampled near trimmed industrial strip edges are deformed using the URT stand. Two sets of specimens with different stress states, obtained by annealing, are submitted to two reduction passes with extreme forward slips.Scanning electron microscopy observations added to 3D optical surface profiler topographies show that on one hand, forward slip has a major effect on cracks opening. On the other hand, cracks opening decreases according to high roll strip speed gradient. Concerning the heat-treated specimens, no crack appeared after all reduction passes, showing a large influence of the cutting process and consequently of the local stress state in the vicinity of the burnish and fracture regions.
Byrne, Mike
of the federal Voluntary Voting System Guidelines (2007) contains recommendations regarding the manual audit audits of election ballots, comparing the auditability of different types of ballot systems has become Electronic (DRE) voting systems equipped with Voter Verified Paper Audit Trail (VVPAT) modules or optical
) select and use appropriate units and formulas to measure length, perimeter, area, and volume. Science: 5 standard units of measure. Point out that not all of the display measuring instruments have the same1 TREE TRAILS Tree measurement is fundamental to the practice of forestry. Foresters count trees
Li, Xiaolin "Andy"
battery life, energy saving is of paramount importance in the design of sensor network protocols. Recent transmission path is greatly shortened and energy consumption for relaying is reduced. However, data gatheringTrailing Mobile Sinks: A Proactive Data Reporting Protocol for Wireless Sensor Networks Xinxin Liu
Three-dimensional metrics as deformations of a constant curvature metric
B. Coll; J. Llosa; D. Soler
2001-04-23
Any three-dimensional Riemannian metric can be locally obtained by deforming a constant curvature metric along one direction. The general interest of this result, both in geometry and physics, and related open problems are stressed.
Estimation of the curvature of an interface from a digital 2D image
Frette, O.I.; Virnovsky, G.; Silin, D.
2008-10-15
In this paper a method for the estimation of the curvature along a condensed phase interface is presented. In a previous paper in this journal [1] a mathematical relationship was established between this curvature and a template disk located at a given point along the interface. The portion of the computed area of the template disk covering one of the phases was shown to be asymptotically linear in the mean curvature. Instead of utilizing this relationship, an empirical approach was proposed in [1] in order to compensate for discrete uncertainties. In this paper, we show that this linear relationship can be used directly along the interface avoiding the empirical approach proposed earlier. Modifications of the algorithm are however needed, and with good data smoothing techniques, our method provides good quantitative curvature estimates.
A New Force-Directed Graph Drawing Method Based on Edge-Edge Repulsion$
Yen, Hsu-Chun
-vertex repulsion model in which vertices are replaced with charged steel rings and edges with springs to form the paradigm of simulated annealing, suited for combinatorial optimization problems, to draw graphs
Space-time curvature due to quantum vacuum fluctuations: An alternative to dark energy?
Santos, Emilio
2010-01-01
It is pointed out that quantum vacuum fluctuations may give rise to a curvature of space-time equivalent to the curvature currently attributed to dark energy. A simple calculation is made, which suggests that the value of the dark energy density is roughly given by the product of Newton constant time the quantity m^6 c^4 h^-4, m being a typical mass of elementary particles. The estimate is compatible with observations.
Space-time curvature due to quantum vacuum fluctuations: An alternative to dark energy?
Emilio Santos
2009-12-30
It is pointed out that quantum vacuum fluctuations may give rise to a curvature of space-time equivalent to the curvature currently attributed to dark energy. A simple calculation is made, which suggests that the value of the dark energy density is roughly given by the product of Newton constant time the quantity m^6 c^4 h^-4, m being a typical mass of elementary particles. The estimate is compatible with observations.
Synchro-curvature radiation of charged particles in the strong curved magnetic fields
Kelner, S. R.; Prosekin, A. Yu.; Aharonian, F. A., E-mail: Stanislav.Kelner@mpi-hd.mpg.de, E-mail: Anton.Prosekin@mpi-hd.mpg.de, E-mail: Felix.Aharonian@mpi-hd.mpg.de [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)
2015-01-01
It is generally believed that the radiation of relativistic particles in a curved magnetic field proceeds in either the synchrotron or the curvature radiation modes. In this paper we show that in strong curved magnetic fields a significant fraction of the energy of relativistic electrons can be radiated away in the intermediate, the so-called synchro-curvature regime. Because of the persistent change of the trajectory curvature, the radiation varies with the frequency of particle gyration. While this effect can be ignored in the synchrotron and curvature regimes, the variability plays a key role in the formation of the synchro-curvature radiation. Using the Hamiltonian formalism, we find that the particle trajectory has the form of a helix wound around the drift trajectory. This allows us to calculate analytically the intensity and energy distribution of prompt radiation in the general case of magnetic bremsstrahlung in the curved magnetic field. We show that the transition to the limit of the synchrotron and curvature radiation regimes is determined by the relation between the drift velocity and the component of the particle velocity perpendicular to the drift trajectory. The detailed numerical calculations, which take into account the energy losses of particles, confirm the principal conclusions based on the simplified analytical treatment of the problem, and allow us to analyze quantitatively the transition between different radiation regimes for a broad range of initial pitch angles. These calculations demonstrate that even very small pitch angles may lead to significant deviations from the spectrum of the standard curvature radiation when it is formally assumed that a charged particle moves strictly along the magnetic line. We argue that in the case of realization of specific configurations of the electric and magnetic fields, the gamma-ray emission of the pulsar magnetospheres can be dominated by the component radiated in the synchro-curvature regime.
Geometric Design of Spherical Serial Chains with Curvature Constraints in the Environment
Tolety, Anurag Bharadwaj
2012-10-19
2011 Major Subject: Electrical Engineering GEOMETRIC DESIGN OF SPHERICAL SERIAL CHAINS WITH CURVATURE CONSTRAINTS IN THE ENVIRONMENT A Thesis by ANURAG BHARADWAJ TOLETY Submitted to the O ce of Graduate Studies of Texas A&M University in partial... Georghiades August 2011 Major Subject: Electrical Engineering iii ABSTRACT Geometric Design of Spherical Serial Chains with Curvature Constraints in the Environment. (August 2011) Anurag Bharadwaj Tolety, B. Tech., Indian Institute of Technology...
Dean, J.; Gu, T.; Clyne, T. W.
2014-11-09
of the residual substrate was obtained, via SEM microscopy of polished cross-sections. 2.3. Curvature measurement Residual stress in coatings formed on such thin strips will tend to give rise to curvature, which can be measured in order to obtain information about... plasma channels through to the substrate, combination of themetalwith oxygen in the vapour phase and melting of surrounding regions, followed by rapid condensation and solidification, and the creation of porosity and micro-cracks. Furthermore, even...
On the Dependence of Charge Density on Surface Curvature of an Isolated Conductor
Bhattacharya, Kolahal
2015-01-01
A study of the relation between the electrostatic charge density at a point on a conducting surface and the curvature of the surface (at that point) is presented. Two major scientific literature on this topic are reviewed and the apparent discrepancy between them is resolved. Hence, a step is taken towards obtaining a general analytic formula for relating the charge density with surface curvature of conductors. The merit of this formula and its limitations are discussed.
Imaging topological edge states in silicon photonics
M. Hafezi; S. Mittal; J. Fan; A. Migdall; J. Taylor
2015-04-03
Topological features - global properties not discernible locally - emerge in systems from liquid crystals to magnets to fractional quantum Hall systems. Deeper understanding of the role of topology in physics has led to a new class of matter: topologically - ordered systems. The best known examples are quantum Hall effects, where insensitivity to local properties manifests itself as conductance through edge states that is insensitive to defects and disorder. Current research in engineering topological order primarily focuses on analogies to quantum Hall systems, where the required magnetic field is synthesized in non-magnetic systems. Here, we realize synthetic magnetic fields for photons at room temperature, using linear Silicon photonics. We observe, for the first time, topological edge states of light in a two - dimensional system and show their robustness against intrinsic and introduced disorder. Our experiment demonstrates the feasibility of using photonics to realize topological order in both the non-interacting and many-body regimes.
Permanent magnet edge-field quadrupole
Tatchyn, Roman O. (Mountain View, CA)
1997-01-01
Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis.
Rimmed and edge thickened Stodola shaped flywheel
Kulkarni, S.V.; Stone, R.G.
1983-10-11
A flywheel is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel has a body composed of essentially planar isotropic high strength material. The flywheel body is enclosed by a rim of circumferentially wound fiber embedded in resin. The rim promotes flywheel safety and survivability. The flywheel has a truncated and edge thickened Stodola shape designed to optimize system mass and energy storage capability. 6 figs.
Leading Edge Technologies Inc | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History View NewTexas:Montezuma, Arizona: Energy ResourcesProjectMississippi: EnergyLawrieEdge Technologies
Tracking Objects Using 3D Edge Detectors February 2013
O'Leary, Dianne P.
Tracking Objects Using 3D Edge Detectors February 2013 SIAM CSE 2013 Dianne P. O'Leary c 2013 1 #12;Tracking Objects Using 3D Edge Detectors Dianne P. O'Leary Computer Science Dept. and Institute
Ames, Forrest; Bons, Jeffrey
2014-09-30
The Department of Energy has goals to move land based gas turbine systems to alternate fuels including coal derived synthetic gas and hydrogen. Coal is the most abundant energy resource in the US and in the world and it is economically advantageous to develop power systems which can use coal. Integrated gasification combined cycles are (IGCC) expected to allow the clean use of coal derived fuels while improving the ability to capture and sequester carbon dioxide. These cycles will need to maintain or increase turbine entry temperatures to develop competitive efficiencies. The use of coal derived syngas introduces a range of potential contaminants into the hot section of the gas turbine including sulfur, iron, calcium, and various alkali metals. Depending on the effectiveness of the gas clean up processes, there exists significant likelihood that the remaining materials will become molten in the combustion process and potentially deposit on downstream turbine surfaces. Past evidence suggests that deposition will be a strong function of increasing temperature. Currently, even with the best gas cleanup processes a small level of particulate matter in the syngas is expected. Consequently, particulate deposition is expected to be an important consideration in the design of turbine components. The leading edge region of first stage vanes most often have higher deposition rates than other areas due to strong fluid acceleration and streamline curvature in the vicinity of the surface. This region remains one of the most difficult areas in a turbine nozzle to cool due to high inlet temperatures and only a small pressure ratio for cooling. The leading edge of a vane often has relatively high heat transfer coefficients and is often cooled using showerhead film cooling arrays. The throat of the first stage nozzle is another area where deposition potentially has a strongly adverse effect on turbine performance as this region meters the turbine inlet flow. Based on roughness levels found on in service vanes (Bons, et al., 2001, up to 300 microns) flow blockage in first stage turbine nozzles can easily reach 1 to 2 percent in conventional turbines. Deposition levels in syngas fueled gas turbines are expected to be even more problematic. The likelihood of significant deposition to the leading edge of vanes in a syngas environment indicates the need to examine this effect on the leading edge cooling problem. It is critical to understand the influence of leading edge geometry and turbulence on deposition rates for both internally and showerhead cooled leading edge regions. The expected level of deposition in a vane stagnation region not only significantly changes the heat transfer problem but also suggests that cooling arrays may clog. Addressing the cooling issue suggests a need to better understand stagnation region heat transfer with realistic roughness as well as the other variables affecting transport near the leading edge. Also, the question of whether leading edge regions can be cooled internally with modern cooling approaches should also be raised, thus avoiding the clogging issue. Addressing deposition in the pressure side throat region of the nozzle is another critical issue for this environment. Issues such as examining the protective effect of slot and full coverage discrete-hole film cooling on limiting deposition as well as the influence of roughness and turbulence on effectiveness should be raised. The objective of this present study is to address these technical challenges to help enable the development of high efficiency syngas tolerant gas turbine engines.
Edge-based correlation image registration for multispectral imaging
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.
Walker, Thad G.
DAMOP BICYCLE EXCURSION Wisconsin led in the Rail to Trail conversion are invited on a bicycle excursion organized by Thad Walker and Jim Lawler. Directions & Costs: The excursion will depart from Machinery Row Bicycles (0.4 mi
Coaxial connector for use with printed circuit board edge connector
Howard, Donald R. (Danville, CA); MacGill, Robert A. (Richmond, CA)
1989-01-01
A coaxial cable connector for interfacing with an edge connector for a printed circuit board whereby a coaxial cable can be interconnected with a printed circuit board through the edge connector. The coaxial connector includes a body having two leg portions extending from one side for receiving the edge connector therebetween, and a tubular portion extending from an opposing side for receiving a coaxial cable. A cavity within the body receives a lug of the edge connector and the center conductor of the coaxial cable. Adjacent lugs of the edge connector can be bend around the edge connector housing to function as spring-loaded contacts for receiving the coaxial connector. The lugs also function to facilitate shielding of the center conductor where fastened to the edge connector lug.
K-edge densitometer (KED). User manual
Sprinkle, J.K.; Hansen, W.J.
1993-02-11
In 1979, a K-edge densitometer (KED) was installed by the Safeguards Assay group from Los Alamos National Laboratory in the PNC reprocessing plant at Tokai-mura, Japan. It uses an active nondestructive assay technique, KED, to measure the plutonium concentration of the product solution. The measurement uncertainty of an assay depends on the count time chosen, but can be 0.5% or better. The computer hardware and software were upgraded in 1992. This manual describes the operation of the instrument, with an emphasis on the user interface to the software.
Rimmed and edge thickened Stodola shaped flywheel
Kulkarni, Satish V. (San Ramon, CA); Stone, Richard G. (Oakland, CA)
1983-01-01
A flywheel (10) is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel (10) has a body (15) composed of essentially planar isotropic high strength material. The flywheel (10) body (15) is enclosed by a rim (50) of circumferentially wound fiber (2) embedded in resin (3). The rim (50) promotes flywheel (10) safety and survivability. The flywheel (10) has a truncated and edge thickened Stodola shape designed to optimize system mass and energy storage capability.
EDGE Energy LLC | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX E LIST OFAMERICA'SHeavy Electricals Ltd BHELEuropeLagePowerTimo JV JumpEDGE Energy LLC
Superintegrable potentials on 3D Riemannian and Lorentzian spaces with nonconstant curvature
Ballesteros, A., E-mail: angelb@ubu.e [Universidad de Burgos, Departamento de Fisica, Facultad de Ciencias (Spain); Enciso, A., E-mail: aenciso@fis.ucm.e [Universidad Complutense, Departamento de Fisica Teorica II (Spain); Herranz, F. J., E-mail: fjherranz@ubu.e [Universidad de Burgos, Departamento de Fisica, Escuela Politecnica Superior (Spain); Ragnisco, O., E-mail: ragnisco@fis.uniroma3.i [Universita di Roma Tre and Istituto Nazionale di Fisica Nucleare sezione di Roma Tre, Dipartimento di Fisica (Italy)
2010-02-15
A quantum sl(2,R) coalgebra (with deformation parameter z) is shown to underly the construction of a large class of superintegrable potentials on 3D curved spaces, that include the nonconstant curvature analog of the spherical, hyperbolic, and (anti-)de Sitter spaces. The connection and curvature tensors for these 'deformed' spaces are fully studied by working on two different phase spaces. The former directly comes from a 3D symplectic realization of the deformed coalgebra, while the latter is obtained through a map leading to a spherical-type phase space. In this framework, the nondeformed limit z {yields} 0 is identified with the flat contraction leading to the Euclidean and Minkowskian spaces/potentials. The resulting Hamiltonians always admit, at least, three functionally independent constants of motion coming from the coalgebra structure. Furthermore, the intrinsic oscillator and Kepler potentials on such Riemannian and Lorentzian spaces of nonconstant curvature are identified, and several examples of them are explicitly presented.
Null test of the cosmic curvature using $H(z)$ and supernovae data
Cai, Rong-Gen; Yang, Tao
2015-01-01
We introduce a model-independent approach to the null test of the cosmic curvature which is geometrically related to the Hubble parameter $H(z)$ and luminosity distance $d_L(z)$. Combining the independent observations of $H(z)$ and $d_L(z)$, we use the model-independent smoothing technique, Gaussian processes, to reconstruct them and determine the cosmic curvature $\\Omega_K^{(0)}$ in the null test relation. The null test is totally geometrical and without assuming any cosmological model. We show that the cosmic curvature $\\Omega_K^{(0)}=0$ is consistent with current observational data sets, falling within the $1\\sigma$ limit. To demonstrate the effect on the precision of the null test, we produce a series of simulated data of the models with different $\\Omega_K^{(0)}$. Future observations in better quality can provide a greater improvement to constrain or refute the flat universe with $\\Omega_K^{(0)}=0$.
The Sound Edge of the Quenching Jets
Edward Shuryak; Pilar Staig
2013-07-19
When quenching jets deposit certain amount of energy and momentum into ambient matter, part of it propagates in the form of shocks/sounds. The "sound surface", separating disturbed and undisturbed parts of the fireball, makes what we call the sound edge of jets. In this work we semi-analytically study its shape, in various geometries. We further argue that since hadrons with in the kinematical range of $p_\\perp\\sim 2\\, GeV$ originate mostly from the "rim" of the fireball, near the maximum of the radial flow at the freezeout surface, only the intersection of the "sound surface" with this "rim" would be observable. The resulting "jet edge" has a form of extra matter at the elliptic curve, in $\\Delta \\phi, \\Delta \\eta$ coordinates, with radius $|\\Delta \\phi| \\sim |\\Delta \\eta |\\sim 1$. In the case of large energy/momentum deposition $\\sim 100 \\, GeV$ we argue that the event should be considered as two sub-events, with interior of the "sound surface" having modified radial and directed flow. We further argue that in the kinematical range of $p_\\perp\\sim 3\\, GeV$ the effect of that can be large enough to be seen on event-by-event basis. If so, this effect has a potential to become a valuable tool to address geometry of jet production and quenching.
Volume Reflection Dependence of 400 GeV/c Protons on the Bent Crystal Curvature
Scandale, W.; Vomiero, A.; Baricordi, S.; Dalpiaz, P.; Fiorini, M.; Guidi, V.; Mazzolari, A.; Milan, R.; Della Mea, Gianantonio; Ambrosi, G.; Zuccon, P.; Bertucci, B.; Burger, W. J.; Duranti, M.; Cavoto, G.; Santacesaria, R.; Valente, P.; Iacoangeli, F.; Pisano, S.; Luci, C.
2008-12-05
The trend of volume reflection parameters (deflection angle and efficiency) in a bent (110) silicon crystal has been investigated as a function of the crystal curvature with 400 GeV/c protons on the H8 beam line at the CERN Super Proton Synchrotron. This Letter describes the analysis performed at six different curvatures showing that the optimal radius for volume reflection is approximately 10 times greater than the critical radius for channeling. A strong scattering of the beam by the planar potential is also observed for a bend radius close to the critical one.
Rodrigo Alonso; Elizabeth E. Jenkins; Aneesh V. Manohar
2015-11-02
A geometric formulation of Higgs Effective Field Theory (HEFT) is presented. Experimental observables are given in terms of geometric invariants of the scalar sigma model sector such as the curvature of the scalar field manifold $\\mathcal M$. We show how the curvature can be measured experimentally via Higgs cross-sections, $W_L$ scattering, and the $S$ parameter. The one-loop action of HEFT is given in terms of geometric invariants of $\\mathcal M$. The distinction between the Standard Model (SM) and HEFT is whether $\\mathcal M$ is flat or curved, not whether the scalars transform linearly or non-linearly under the electroweak group.
Microchannel Cooled Edge Cladding to Establish an Adiabatic Boundary Condition in a Slab Laser
Albrecht, Georg F.; Beach, Raymond J.; Solarz, Richard W.
2004-05-18
The present invention provides an edge cladding for a slab laser, the edge cladding comprising a cooling channel system therein.
Time-Resonant Tokamak Plasma Edge Instabilities?
Webster, A J; Calderon, F A; Chapman, S C; Delabie, E; Dodt, D; Felton, R; Todd, T N; Maviglia, F; Morris, J; Riccardo, V; Alper, B; Brezinsek, S; Coad, P; Likonen, J; Rubel, M; Contributors, JET EFDA
2013-01-01
For a two week period during the Joint European Torus (JET) 2012 experimental campaign, the same high confinement plasma was repeated 151 times. The dataset was analysed to produce a probability density function (pdf) for the waiting times between edge-localised plasma instabilities ("ELMS"). The result was entirely unexpected. Instead of a smooth single peaked pdf, a succession of 4-5 sharp maxima and minima uniformly separated by 7-8 millisecond intervals was found. Here we explore the causes of this newly observed phenomenon, and conclude that it is either due to a self-organised plasma phenomenon or an interaction between the plasma and a real-time control system. If the maxima are a result of "resonant" frequencies at which ELMs can be triggered more easily, then future ELM control techniques can, and probably will, use them. Either way, these results demand a deeper understanding of the ELMing process.
Casimir force at a knife's edge
Graham, Noah [Department of Physics, Middlebury College, Middlebury, Vermont 05753 (United States); Shpunt, Alexander; Rahi, Sahand Jamal; Kardar, Mehran [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Emig, Thorsten [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Institut fuer Theoretische Physik, Universitaet zu Koeln, Zuelpicher Strasse 77, 50937 Koeln (Germany); Laboratoire de Physique Theorique et Modeles Statistiques, CNRS UMR 8626, Batiment 100, Universite Paris-Sud, 91405 Orsay cedex (France); Jaffe, Robert L. [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Center for Theoretical Physics and Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
2010-03-15
The Casimir force has been computed exactly for only a few simple geometries, such as infinite plates, cylinders, and spheres. We show that a parabolic cylinder, for which analytic solutions to the Helmholtz equation are available, is another case where such a calculation is possible. We compute the interaction energy of a parabolic cylinder and an infinite plate (both perfect mirrors), as a function of their separation and inclination, H and {theta}, and the cylinder's parabolic radius R. As H/R{yields}0, the proximity force approximation becomes exact. The opposite limit of R/H{yields}0 corresponds to a semi-infinite plate, where the effects of edge and inclination can be probed.
Integral edge seals for phosphoric acid fuel cells
Granata, Jr., Samuel J. (South Greensburg, PA); Woodle, Boyd M. (North Huntingdon Township, Westmoreland County, PA); Dunyak, Thomas J. (Blacksburg, VA)
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.
Edge Transport in 2D Cold Atom Optical Lattices
V. W. Scarola; S. Das Sarma
2007-05-24
We theoretically study the observable response of edge currents in two dimensional cold atom optical lattices. As an example we use Gutzwiller mean-field theory to relate persistent edge currents surrounding a Mott insulator in a slowly rotating trapped Bose-Hubbard system to time of flight measurements. We briefly discuss an application, the detection of Chern number using edge currents of a topologically ordered optical lattice insulator.
Relativistic static thin dust disks with an inner edge: An infinite family of new exact solutions
Gonzalez, Guillermo A.; Gutierrez-Pineres, Antonio C.; Vina-Cervantes, Viviana M.
2009-06-15
An infinite family of new exact solutions of the vacuum Einstein equations is presented. The solutions are static and axially symmetric and correspond to an infinite family of thin dust disks with a central inner edge. The metric functions of all the solutions can be explicitly computed, and can be expressed in a simple manner in terms of oblate spheroidal coordinates. The energy density of all the disks of the family is positive everywhere and well behaved, so that the corresponding energy-momentum tensor is in full agreement with all the energy conditions. Moreover, although the total mass of the disks is infinite, the solutions are asymptotically flat and the Riemann tensor is regular everywhere, as it is shown by computing the curvature scalars. Now, besides its importance as a new family of exact solutions of the vacuum Einstein equations, the main importance of this family of solutions is that it can be easily superposed with the Schwarzschild solution in order to describe thin disks surrounding a central black hole. Accordingly, a detailed analysis of this superposition will be presented in a subsequent paper.
Edge Plasma Boundary Layer Generated By Kink Modes in Tokamaks
L.E. Zakharov
2010-11-22
This paper describes the structure of the electric current generated by external kink modes at the plasma edge using the ideally conducting plasma model. It is found that the edge current layer is created by both wall touching and free boundary kink modes. Near marginal stability, the total edge current has a universal expression as a result of partial compensation of the ?-functional surface current by the bulk current at the edge. The resolution of an apparent paradox with the pressure balance across the plasma boundary in the presence of the surface currents is provided.
Electron spin magnetism of zigzag graphene nanoribbon edge states
Xu, Kun Ye, Peide D.
2014-04-21
The electron spin states of zigzag graphene nanoribbon (ZGNR) edge play a pivotal role in the applications of graphene nanoribbons. However, the exact arrangements of the electron spins remain unclear to date. In this report, the electronic spin states of the ZGNR edge have been elucidated through a combination of quantum chemical investigation and previous electron spin resonance experiment observations. An alternating ? and ? spin configuration of the unpaired electrons along the ZGNR edge is established in ambient condition without any external magnetic field, and the origin of the spin magnetism of the ZGNR edge is revealed. It paves a pathway for the understanding and design of graphene based electronic and spintronic devices.
Edge Turbulence Velocity Changes with Lithium Coating on NSTX
Cao, A.; Zweben, S. J.; Stotler, D. P.; Bell, M.; Diallo, A.; Kaye, S. M.; LeBlanc, B.
2012-08-10
Lithium coating improves energy confinement and eliminates edge localized modes in NSTX, but the mechanism of this improvement is not yet well understood. We used the gas-puff-imaging (GPI) diagnostic on NSTX to measure the changes in edge turbulence which occurred during a scan with variable lithium wall coating, in order to help understand the reason for the confinement improvement with lithium. There was a small increase in the edge turbulence poloidal velocity and a decrease in the poloidal velocity fluctuation level with increased lithium. The possible effect of varying edge neutral density on turbulence damping was evaluated for these cases in NSTX. __________________________________________________
The Inverting Effect of Curvature in Winter Terrain Park Jump Takeoffs J. A. McNeil
a significantly greater head/neck injury risk to resort patrons than normal skiing activities [14]. One intentionally, curvature in the takeoff can lead to involuntary inversion. In this work we lay out the basic a potential injury risk. A mitigating takeoff design criterion adopted by the US Terrain Park Council based
Hubert L. Bray
2009-02-18
In this thesis we describe how minimal surface techniques can be used to prove the Penrose inequality in general relativity for two classes of 3-manifolds. We also describe how a new volume comparison theorem involving scalar curvature for 3-manifolds follows from these same techniques.
Abbeel, Pieter
Brachytherapy Sachin Patil, Jia Pan, Pieter Abbeel, Ken Goldberg University of California, Berkeley Abstract for intracavitary brachytherapy treatment. Constraints on the curvature and torsion avoid disconti- nuities (kinks application of intracavitary brachytherapy where radioactive doses have to be delivered to cancerous tumors
Abbeel, Pieter
brachytherapy dose delivery or channels for cooling turbine blades, and path planning for unmanned aerial implants for intracavitary brachytherapy. I. INTRODUCTION The need for curvature-constrained motion a radioactive source is guided for delivering radiation doses for high dose rate brachytherapy (HDR-BT) (Fig. 1
THE GEOMETRY OF EMBEDDED CONSTANT MEAN CURVATURE TORI IN THE 3-SPHERE VIA INTEGRABLE SYSTEMS
Hauswirth, Laurent
THE GEOMETRY OF EMBEDDED CONSTANT MEAN CURVATURE TORI IN THE 3-SPHERE VIA INTEGRABLE SYSTEMS L Alexandrov embedded cylinders is explicitly determined. We prove that all embedded cmc tori in the 3-sphere are surfaces of revolution using a combination of integrable systems methods and geometric analysis techniques
Glasser, Adrian
Changes in crystalline lens radii of curvature and lens tilt and decentration during dynamic of Houston, College of Optometry, Houston, TX, USAAdrian Glasser Dynamic changes in crystalline lens radii accommodation, phakometry, tilt, decentration, crystalline, presbyopia Citation: Rosales, P., Wendt, M., Marcos
REAL TIME, IN-SITU CURVATURE MEASUREMENTS OF EPITAXIAL YBCO FILMS ON MGO
Rosakis, Ares J.
even the most robust electron based diagnostics. Optical methods are preferable and typically have been of the Ælm are desirable for diagnostics. Based on beam shearing methods, Coherent Gradient Sensing is a full gradient sensing (CGS) as an in-situ diagnostic in an MOCVD reactor to measure curvature and changes
Electrostatic Operation and Curvature Modeling for a MEMS Flexible Film Actuator
Electrostatic Operation and Curvature Modeling for a MEMS Flexible Film Actuator B. Edmonds, Jr.1 Introduction and Motivation The electrostatic flexible film actuator, also known as an "Artificial Eyelid," is a unique MEMS (MicroElectronic Mechanical System) actuator fabricated from polyimide and thin metal films
Mechanics Systems on Para-Kaehlerian Manifolds of Constant J-Sectional Curvature
Mehmet Tekkoyun
2009-02-20
The goal of this paper is to present Euler-Lagrange and Hamiltonian equations on R2n which is a model of para-Kaehlerian manifolds of constant J-sectional curvature. In conclusion, some differential geometrical and physical results on the related mechanic systems have been given.
The Smooth Curvature Flexure Model: An Accurate, Low-Dimensional Approach for Robot Analysis
Haller, Gary L.
The Smooth Curvature Flexure Model: An Accurate, Low-Dimensional Approach for Robot Analysis Lael presents a new and comprehensive method of modeling robots having highly flexible members such as flexure of robotic hardware. A number of studies into the behavior of flexible link robots have been conducted, often
Ben-Shaul, Avinoam
described""2). In this paper, we argue that when a bending energy of the rim, namely a curvature dependent. A lattice Hamiltonian is used to describe the bending energy of the rim: An occupied lattice site corresponds to a minimum, disklike, micelle, and a bending energy penalty is associated with corners
Lyapunov spectra in fast dynamo Ricci flows of negative sectional curvature
Garcia de Andrade
2008-11-25
Previously Chicone, Latushkin and Montgomery-Smith [\\textbf{Comm. Math. Phys. \\textbf{173},(1995)}] have investigated the spectrum of the dynamo operator for an ideally conducting fluid. More recently, Tang and Boozer [{\\textbf{Phys. Plasmas (2000)}}], have investigated the anisotropies in magnetic field dynamo evolution, from finite-time, Lyapunov exponents, giving rise to a Riemann metric tensor, in the Alfven twist in magnetic flux tubes (MFTs). In this paper one investigate the role of Perelman Ricci flows constraints in twisted magnetic flux tubes, where the Lyapunov eigenvalue spectra for the Ricci tensor associated with the Ricci flow equation in MFTs leads to a finite-time Lyapunov exponential stretching along the toroidal direction of the tube and a contraction along the radial direction of the tube. It is shown that in the case of MFTs, the sectional Ricci curvature of the flow, is negative as happens in geodesic flows of Anosov type. Ricci flows constraints in MFTs substitute the Thiffeault and Boozer [\\textbf{Chaos}(2001)] have vanishing of Riemann curvature constraint on the Lyapunov exponential stretching of chaotic flows. Gauss curvature of the twisted MFT is also computed and the contraints on a negative Gauss curvature are obtained.
Yoshida, Kenji; Takagi, Toshimi
1999-07-01
Experimental and numerical studies are made of transient H{sub 2}/N{sub 2}--air counterflow diffusion flames unsteadily strained by an impinging micro jet. Two-dimensional temperature measurements by laser Rayleigh scattering method and numerical computations taking into account detailed chemical kinetics are conducted paying attention to transient local extinction and reignition in relation to the unsteadiness, flame curvature and preferential diffusion effects. The results are as follows. (1) Transient local flame extinction is observed where the micro jet impinges. But, the transient flame can survive instantaneously in spite of quite high stretch rate where the steady flame cannot exist. (2) Reignition is observed after the local extinction due to the micro air jet impingement. The temperature after reignition becomes significantly higher than that of the original flame. This high temperature is induced by the concentration of H{sub 2} species due to the preferential diffusion in relation to the concave curvature. The predicted behaviors of the local transient extinction and reignition are well confirmed by the experiments. (3) The reignition is induced after the formation of combustible premixed gas mixture and the consequent flame propagation. (4) The reignition is hardly observed after the extinction by micro fuel jet impingement. This is due to the dilution of H{sub 2} species induced by the preferential diffusion in relation to the convex curvature. (5) The maximum flame temperature cannot be rationalized by the stretch rate but changes widely depending on the unsteadiness and the flame curvature in relation with preferential diffusion.
Heat transfer in soft nanoscale interfaces: the influence of interface curvature
Kjelstrup, Signe
Heat transfer in soft nanoscale interfaces: the influence of interface curvature Anders Lervik transient non-equilibrium molecular-dynamics simulations, heat-transfer through nanometer-scale interfaces processes. We show that the modeling of heat transfer across a nanodroplet/fluid interface requires
Sandia Energy - Offshore Wind RD&D: Large Offshore Rotor Development
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
utilized balsa in critical buckling areas (Trailing Edge Panel: Inboard) and PET foam in the non-critical buckling areas (Trailing Edge Panel: Outboard), as shown in the...
Basin boundary, edge of chaos, and edge state in a two-dimensional model
J. Vollmer; T. M. Schneider; B. Eckhardt
2008-08-19
In shear flows like pipe flow and plane Couette flow there is an extended range of parameters where linearly stable laminar flow coexists with a transient turbulent dynamics. When increasing the amplitude of a perturbation on top of the laminar flow, one notes a a qualitative change in its lifetime, from smoothly varying and short one on the laminar side to sensitively dependent on initial conditions and long on the turbulent side. The point of transition defines a point on the edge of chaos. Since it is defined via the lifetimes, the edge of chaos can also be used in situations when the turbulence is not persistent. It then generalises the concept of basin boundaries, which separate two coexisting attractors, to cases where the dynamics on one side shows transient chaos and almost all trajectories eventually end up on the other side. In this paper we analyse a two-dimensional map which captures many of the features identified in laboratory experiments and direct numerical simulations of hydrodynamic flows. The analysis of the map shows that different dynamical situations in the edge of chaos can be combined with different dynamical situations in the turbulent region. Consequently, the model can be used to develop and test further characterisations that are also applicable to realistic flows.
Blazing trails: Microquasars as head-tail sources and the seeding of magnetized plasma into the ISM
S. Heinz; H. J. Grimm; R. A. Sunyaev; R. P. Fender
2008-08-14
We discuss the dynamics of microquasar jets in the interstellar medium, with specific focus on the effects of the X-ray binaries' space velocity with respect to the local Galactic standard of rest. We argue that, during late stages in the evolution of large scale radio nebulae around microquasars, the ram pressure of the interstellar medium due to the microquasar's space velocity becomes important and that microquasars with high velocities form the Galactic equivalent of extragalactic head-tail sources, i.e., that they leave behind trails of stripped radio plasma. Because of their higher space velocities, low-mass X-ray binaries are more likely to leave trails than high-mass X-ray binaries. We show that the volume of radio plasma released by microquasars over the history of the Galaxy is comparable to the disk volume and argue that a fraction of a few percent of the radio plasma left behind by the X-ray binary is likely mixed with the neutral phases of the ISM before the plasma is removed from the disk by buoyancy. Because the formation of microquasars is an unavoidable by-product of star formation, and because they can travel far from their birth places, their activity likely has important consequences for the evolution of magnetic fields in forming galaxies. We show that radio emission from the plasma inside the trail should be detectable at low frequencies. We suggest that LMXBs with high detected proper motions like XTE J1118+480 will be the best candidates for such a search.
Enhanced Half-Metallicity in Edge-Oxidized Zigzag Graphene
Hod, Oded
Enhanced Half-Metallicity in Edge-Oxidized Zigzag Graphene Nanoribbons Oded Hod,* Vero“nica Barone theoretical study of the electronic properties and relative stabilities of edge-oxidized zigzag graphene with nanometer scale dimen- sions. Recently, a new type of graphene-based material was experimentally realized.12
Sparsification of Motion-Planning Roadmaps by Edge Contraction
Agarwal, Pankaj K.
Sparsification of Motion-Planning Roadmaps by Edge Contraction Doron Shaharabani, Oren Salzman Department of Computer Science, Duke University, USA Abstract--We present Roadmap Sparsification by Edge Con- traction (RSEC), a simple and effective algorithm for reducing the size of a motion-planning roadmap
Active Control of Plasma Boundaries Using Edge Currents
Budny, Robert
response and low power levels. - independent of vessel magnetic penetration time scales. · Useful boundaries using edge currents has been demonstrated in numerous experiments to produce edge conditions fields on a faster time scale and with less power than external magnetic field coils. - fast time
Edge profile measurements using Thomson scattering on the KSTAR tokamak
Lee, J. H. Ko, W. H.; Oh, S.; Lee, W. R.; Kim, K. P.; Lee, K. D.; Jeon, Y. M.; Yoon, S. W.; Cho, K. W.; Narihara, K.; Yamada, I.; Yasuhara, R.; Hatae, T.; Yatsuka, E.; Ono, T.; Hong, J. H.
2014-11-15
In the KSTAR Tokamak, a Tangential Thomson Scattering (TTS) diagnostic system has been designed and installed to measure electron density and temperature profiles. In the edge system, TTS has 12 optical fiber bundles to measure the edge profiles with 1015 mm spatial resolution. These 12 optical fibers and their spatial resolution are not enough to measure the pedestal width with a high accuracy but allow observations of L-H transition or H-L transitions at the edge. For these measurements, the prototype ITER edge Thomson Nd:YAG laser system manufactured by JAEA in Japan is installed. In this paper, the KSTAR TTS system is briefly described and some TTS edge profiles are presented and compared against the KSTAR Charge Exchange Spectroscopy and other diagnostics. The future upgrade plan of the system is also discussed in this paper.
Multiscale Edge Detection in the Corona
C. Alex Young; Peter T. Gallagher
2008-04-11
Coronal Mass Ejections (CMEs) are challenging objects to detect using automated techniques, due to their high velocity and diffuse, irregular morphology. A necessary step to automating the detection process is to first remove the subjectivity introduced by the observer used in the current, standard, CME detection and tracking method. Here we describe and demonstrate a multiscale edge detection technique that addresses this step and could serve as one part of an automated CME detection system. This method provides a way to objectively define a CME front with associated error estimates. These fronts can then be used to extract CME morphology and kinematics. We apply this technique to a CME observed on 18 April 2000 by the Large Angle Solar COronagraph experiment (LASCO) C2/C3 and a CME observed on 21 April 2002 by LASCO C2/C3 and the Transition Region and Coronal Explorer (TRACE). For the two examples in this work, the heights determined by the standard manual method are larger than those determined with the multiscale method by approximately 10% using LASCO data and approximately 20% using TRACE data.
Edge-localized-modes in tokamaks
Leonard, A. W.
2014-09-15
Edge-localized-modes (ELMs) are a ubiquitous feature of H-mode in tokamaks. When gradients in the H-mode transport barrier grow to exceed the MHD stability limit the ELM instability grows explosively, rapidly transporting energy and particles onto open field lines and material surfaces. Though ELMs provide additional particle and impurity transport through the H-mode transport barrier, enabling steady operation, the resulting heat flux transients to plasma facing surfaces project to large amplitude in future low collisionality burning plasma tokamaks. Measurements of the ELM heat flux deposition onto material surfaces in the divertor and main chamber indicate significant broadening compared to inter-ELM heat flux, with a timescale for energy deposition that is consistent with sonic ion flow and numerical simulation. Comprehensive ELM simulation is highlighting the important physics processes of ELM transport including parallel transport due to magnetic reconnection and turbulence resulting from collapse of the H-mode transport barrier. Encouraging prospects for ELM control and/or suppression in future tokamaks include intrinsic modes of ELM free operation, ELM triggering with frequent small pellet injection and the application of 3D magnetic fields.
RING EDGE WAVES AND THE MASSES OF NEARBY SATELLITES
Weiss, John W.; Porco, Carolyn C. [CICLOPS/Space Science Institute, Boulder, CO 80301 (United States); Tiscareno, Matthew S. [Cornell University, Ithaca, NY 14853 (United States)
2009-07-15
Moons embedded in gaps within Saturn's main rings generate waves on the gap edges due to their gravitational disturbances. These edge waves can serve as diagnostics for the masses and, in some cases, orbital characteristics of the embedded moons. Although N-body simulations of the edges are far better in inferring masses from edge morphology, the long run-times of this technique often make it impractical. In this paper, we describe a faster approach to narrow the range of masses to explore with N-body simulations, to explore the multidimensional parameter space of edge/moon interactions, and to guide the planning of spacecraft observations. Using numerical, test-particle models and neglecting particle-particle interactions, we demonstrate that the simple analytic theory of the edge waves applies well to Pan in the Encke Gap but breaks down for smaller moons/gaps like Daphnis in the Keeler Gap. Fitting an analytic model to our simulation results allows us to suggest an improved relationship between moon-mass and edge wave amplitude. Numerical methods also grant freedom to explore a wider range of moon and ring orbits than the circular, coplanar case considered by analytic theory. We examine how pre-encounter inclinations and eccentricities affect the properties of the edge waves. In the case where the moon or ring-edge particle orbits initially have eccentric radial variations that are large compared to the gap width, there is considerable variation in edge wave amplitude depending on the orbital phase of the encounter. Inclined moons also affect the edge wave amplitude, potentially significantly, as well as generate vertical waves on the gap-edges. Recent Cassini images acquired as Saturn approaches equinox and the Sun's elevation on the ringplane is extremely low have revealed long shadows associated with the Keeler gap edge waves created by the embedded moon Daphnis. We interpret these as being cast by {approx}1 km high vertical structure in the waves created by Daphnis' out-of-plane perturbations on the ring particles.
Stability of the Horizontal Curvature of the LHC Cryodipoles During Cold Tests
Cano, E D Fernandez; Garcķa-Pérez, J; Jeanneret, Jean Bernard; Poncet, A; Seyvet, F; Tovar-Gonzalez, A; Wildner, E; IEEE Trans. Nucl. Sci.
2006-01-01
The LHC will be composed of 1232 horizontally curved, 15 meter long, superconducting dipole magnets cooled at 1.9 K. They are supported within their vacuum vessel by three Glass Fiber Reinforced Epoxy (GFRE) support posts. Each cryodipole is individually cold tested at CERN before its installation and interconnection in the LHC 27 km circumference tunnel. As the magnet geometry under cryogenic operation is extremely important for the LHC machine aperture, a new method has been developed at CERN in order to monitor the magnet curvature change between warm and cold states. It enabled us to conclude that there is no permanent horizontal curvature change of the LHC dipole magnet between warm and cold states, although a systematic horizontal transient deformation during cool-down was detected. This deformation generates loads in the dipole supporting system; further investigation permitted us to infer this behavior to the asymmetric thermal contraction of the rigid magnet thermal shield during cool-down. Controlli...
Optics design for J-TEXT ECE imaging with field curvature adjustment lens
Zhu, Y.; Zhao, Z.; Liu, W. D.; Xie, J., E-mail: jlxie@ustc.edu.cn [School of Physics, University of Science and Technology of China, Anhui 230026 (China); Hu, X.; Muscatello, C. M.; Domier, C. W.; Luhmann, N. C.; Chen, M.; Ren, X. [University of California at Davis, Davis, California 95616 (United States); Tobias, B. J. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Zhuang, G.; Yang, Z. [College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)
2014-11-15
Significant progress has been made in the imaging and visualization of magnetohydrodynamic and microturbulence phenomena in magnetic fusion plasmas. Of particular importance has been microwave electron cyclotron emission imaging (ECEI) for imaging T{sub e} fluctuations. Key to the success of ECEI is a large Gaussian optics system constituting a major portion of the focusing of the microwave radiation from the plasma to the detector array. Both the spatial resolution and observation range are dependent upon the imaging optics system performance. In particular, it is critical that the field curvature on the image plane is reduced to decrease crosstalk between vertical channels. The receiver optics systems for two ECEI on the J-TEXT device have been designed to ameliorate these problems and provide good performance with additional field curvature adjustment lenses with a meniscus shape to correct the aberrations from several spherical surfaces.
The intrinsic curvature of thermodynamic potentials for black holes with critical points
Dolan, Brian P
2015-01-01
The geometry of thermodynamic state space is studied for asymptotically anti-de Sitter black holes in D-dimensional space times. Convexity of thermodynamic potentials and the analytic structure of the response functions is analysed. The thermodynamic potentials can be used to define a metric on the space of thermodynamic variables and two commonly used such metrics are the Weinhold metric, derived from the internal energy, and the Ruppeiner metric, derived from the entropy. The intrinsic curvature of these metrics is calculated for charged and for rotating black holes and it is shown that the curvature diverges when heat capacities diverge but, contrary to general expectations, the singularities in the Ricci scalars do not reflect the critical behaviour. When a cosmological constant is included as a state space variable it can be interpreted as a pressure and the thermodynamically conjugate variable as a thermodynamic volume. The geometry of the resulting extended thermodynamic state space is also studied, in...
Influence of curvature on the device physics of thin film transistors on flexible substrates
Amalraj, Rex; Sambandan, Sanjiv
2014-10-28
Thin film transistors (TFTs) on elastomers promise flexible electronics with stretching and bending. Recently, there have been several experimental studies reporting the behavior of TFTs under bending and buckling. In the presence of stress, the insulator capacitance is influenced due to two reasons. The first is the variation in insulator thickness depending on the Poisson ratio and strain. The second is the geometric influence of the curvature of the insulator-semiconductor interface during bending or buckling. This paper models the role of curvature on TFT performance and brings to light an elegant result wherein the TFT characteristics is dependent on the area under the capacitance-distance curve. The paper compares models with simulations and explains several experimental findings reported in literature.
Efficiency of the centrifugally induced curvature drift instability in AGN winds
Z. Osmanov
2008-05-09
For studying how the field lines are twisting nearby the light cylinder surface, which provides the free motion of AGN winds through the mentioned area, the investigation of the centrifugally driven curvature drift instability is presented. Studying the dynamics of the relativistic MHD flow close to the light cylinder surface, by applying a single particle approach based on the centrifugal acceleration, the dispersion relation of the instability is derived and analytically solved. Considering the typical values of AGN winds, it is shown that the time scale of the curvature drift instability is much less than the accretion process time scale, indicating that the present instability is very efficient and might strongly influence processes in AGN plasmas.
Quantization of a particle on a two-dimensional manifold of constant curvature
Bracken, Paul [Department of Mathematics, University of Texas, Edinburg, Texas 78540 (United States)
2014-10-15
The formulation of quantum mechanics on spaces of constant curvature is studied. It is shown how a transition from a classical system to the quantum case can be accomplished by the quantization of the Noether momenta. These can be determined by means of Lie differentiation of the metric which defines the manifold. For the metric examined here, it is found that the resulting Schrödinger equation is separable and the spectrum and eigenfunctions can be investigated in detail.
Quantum mechanics on spaces of nonconstant curvature: The oscillator problem and superintegrability
Ballesteros, Angel, E-mail: angelb@ubu.es [Departamento de Fisica, Universidad de Burgos, 09001 Burgos (Spain); Enciso, Alberto, E-mail: aenciso@fis.ucm.es [Departamento de Fisica Teorica II, Universidad Complutense, 28040 Madrid (Spain); Herranz, Francisco J., E-mail: fjherranz@ubu.es [Departamento de Fisica, Universidad de Burgos, 09001 Burgos (Spain); Ragnisco, Orlando, E-mail: ragnisco@fis.uniroma3.it [Dipartimento di Fisica, Universita di Roma Tre and Istituto Nazionale di Fisica Nucleare sezione di Roma Tre, Via Vasca Navale 84, 00146 Roma (Italy); Riglioni, Danilo, E-mail: riglioni@fis.uniroma3.it [Dipartimento di Fisica, Universita di Roma Tre and Istituto Nazionale di Fisica Nucleare sezione di Roma Tre, Via Vasca Navale 84, 00146 Roma (Italy)
2011-08-15
Highlights: > Quantization of Hamiltonians on spaces of nonconstant curvature is addressed. > Our approach is based on superintegrability requirements. > The procedure is applied to a nonlinear classical superintegrable oscillator. > Schroedinger, Laplace-Beltrami and PDM quantizations are worked out. > The quantum system is solved by obtaining the spectrum and the eigenfunctions. - Abstract: The full spectrum and eigenfunctions of the quantum version of a nonlinear oscillator defined on an N-dimensional space with nonconstant curvature are rigorously found. Since the underlying curved space generates a position-dependent kinetic energy, three different quantization prescriptions are worked out by imposing that the maximal superintegrability of the system has to be preserved after quantization. The relationships among these three Schroedinger problems are described in detail through appropriate similarity transformations. These three approaches are used to illustrate different features of the quantization problem on N-dimensional curved spaces or, alternatively, of position-dependent mass quantum Hamiltonians. This quantum oscillator is, to the best of our knowledge, the first example of a maximally superintegrable quantum system on an N-dimensional space with nonconstant curvature.
Measurement of the curvature of a surface using parallel light beams
Chason, E.H.; Floro, J.A.; Seager, C.H.; Sinclair, M.B.
1999-06-15
Apparatus is disclosed for measuring curvature of a surface wherein a beam of collimated light is passed through a means for producing a plurality of parallel light beams each separated by a common distance which then reflect off the surface to fall upon a detector that measures the separation of the reflected beams of light. This means can be an etalon and the combination of a diffractive element and a converging lens. The curvature of the surface along the line onto which the multiple beams fall can be calculated from this information. A two-dimensional map of the curvature can be obtained by adding a second etalon (or a second combination of a diffractive element and a converging lens) which is rotated 90[degree] about the optical axis relative to the first etalon and inclined at the same angle. The second etalon creates an individual set of parallel light beams from each of the individual beams created by the first etalon with the sets of parallel light beams from the second etalon rotated 90[degree] relative to the line onto which the single set of parallel beams from the first etalon would have fallen. 5 figs.
The intrinsic curvature of thermodynamic potentials for black holes with critical points
Brian P. Dolan
2015-04-12
The geometry of thermodynamic state space is studied for asymptotically anti-de Sitter black holes in D-dimensional space times. Convexity of thermodynamic potentials and the analytic structure of the response functions is analysed. The thermodynamic potentials can be used to define a metric on the space of thermodynamic variables and two commonly used such metrics are the Weinhold metric, derived from the internal energy, and the Ruppeiner metric, derived from the entropy. The intrinsic curvature of these metrics is calculated for charged and for rotating black holes and it is shown that the curvature diverges when heat capacities diverge but, contrary to general expectations, the singularities in the Ricci scalars do not reflect the critical behaviour. When a cosmological constant is included as a state space variable it can be interpreted as a pressure and the thermodynamically conjugate variable as a thermodynamic volume. The geometry of the resulting extended thermodynamic state space is also studied, in the context of rotating black holes, and there are curvature singularities when the heat capacity at constant angular velocity diverges and when the black hole is incompressible. Again the critical behaviour is not visible in the singularities of the thermodynamic Ricci scalar.
Stability of bicontinuous cubic phases in ternary amphiphilic systems with spontaneous curvature
U. S. Schwarz; G. Gompper
1999-11-17
We study the phase behavior of ternary amphiphilic systems in the framework of a curvature model with non-vanishing spontaneous curvature. The amphiphilic monolayers can arrange in different ways to form micellar, hexagonal, lamellar and various bicontinuous cubic phases. For the latter case we consider both single structures (one monolayer) and double structures (two monolayers). Their interfaces are modeled by the triply periodic surfaces of constant mean curvature of the families G, D, P, C(P), I-WP and F-RD. The stability of the different bicontinuous cubic phases can be explained by the way in which their universal geometrical properties conspire with the concentration constraints. For vanishing saddle-splay modulus $\\bar \\kappa$, almost every phase considered has some region of stability in the Gibbs triangle. Although bicontinuous cubic phases are suppressed by sufficiently negative values of the saddle-splay modulus $\\bar \\kappa$, we find that they can exist for considerably lower values than obtained previously. The most stable bicontinuous cubic phases with decreasing $\\bar \\kappa < 0$ are the single and double gyroid structures since they combine favorable topological properties with extreme volume fractions.
SciDAC Center for Plasma Edge Simulation
Lin, Zhihong
2013-12-17
This project with a total funding of $592,998 for six years has partially supported four postdoctoral researchers at the University of California, Irvine (UCI). The UCI team has formulated electrostatic and electromagnetic global gyrokinetic particle simulation models with kinetic electrons, implemented these models in the edge code XGC1, performed benchmark between GTC and XGC1, developed computational tools for gyrokinetic particle simulation in tokamak edge geometry, and initiated preparatory study of edge turbulence using GTC code. The research results has been published in 12 papers and presented at many international and national conferences.
Li, Allen
2014-08-10
Seismic attribute analysis in recent decades has been an instrumental tool in improving the quality of reservoir characterization for hydrocarbon identification. Coherency and curvature are geometric seismic attributes which measure seismic...
Choi, Woonjung
2005-08-29
My dissertation focuses on the existence of metrics of non-positive curvature for the simplicial complexes constructed recently by Tom Brady and Daan Krammer for the braid groups and other Artin groups of ?nite type. In particular, for each...
Yannouleas, Constantine
Graphene flakes with defective edge terminations: Universal and topological aspects, and one graphene nanoflakes with reconstructed zigzag edges, where a succes- sion of pentagons and heptagons these spectra. The electronic spectra of trigonal graphene nanoflakes with reczag edge terminations exhibit
Moisture and temperature effects on curvature of anti-symmetric cross-ply graphite/epoxy laminates
Lott, Randall Stephen
1980-01-01
MOISTURE AND TEMPERATURE EFFECTS ON CURVATURE OF ANTI-SYMMETRIC CROSS-PLY GRAPHITE/EPOXY LAMINATES A Thesis by RANDALL STEPHEN LOTT Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE December 1980 Major Subject: Mechanical Engineering MOISTURE AND TEMPERATURE EFFECTS ON CURVATURE OF ANTI-SYMMETRIC CROSS-PLY GRAPHITE/EPOXY LAMINATES A Thesis by RANDALL STEPHEN LOTT Approved as to style and content...
3.3 Construction of vector edge elements
2011-10-05
Figure 3.1: Linear tetrahedral element. 3.3 Construction of vector edge elements. Let us first consider the linear tetrahedral element, as seen in Figure 3.1. Within.
Topological p-n junctions in helical edge states
Disha Wadhawan; Poonam Mehta; Sourin Das
2015-10-08
Quantum spin Hall effect is endowed with topologically protected edge modes with gapless Dirac spectrum. Applying a magnetic field locally along the edge leads to a gapped edge spectrum with opposite parity for winding of spin texture for conduction and valence band. Using Pancharatnam's prescription for geometric phase it is shown that mismatch of this parity across a $p$-$n$ junction, which could be engineered into the edge by electrical gate induced doping, leads to a phase dependence in the two-terminal conductance which is purely topological (0 or $\\pi$). This fact results in a ${\\mathbb{Z}}_2$ classification of such junctions with an associated duality. Current asymmetry measurements which are shown to be robust against electron-electron interactions are proposed to infer this topology.
Evolution of Landau levels into edge states in graphene
Li, Guohong
Two-dimensional electron systems in the presence of a magnetic field support topologically ordered states, in which the coexistence of an insulating bulk with conducting one-dimensional chiral edge states gives rise to the ...
SUPERCONDUCTING TRANSITION EDGE BOLOMETER AND NOISE IN THIN FILMS
Yeh, Nan-Hsiung
2011-01-01
and calculated (---) NEP of transition edge bolometer.performance are described. NEP (noise-equivalent-power)electrical x Io- 15 WHz-1/2 This NEP is within The effective
Longfellow Middle School Edges Out Gildersleeve to Win 2011 Virginia...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Edges Out Gildersleeve to Win 2011 Virginia Middle School Science Bowl 1stplaceLongfellow.jpg The team from Longfellow Middle School, Falls Church, won the 2011 Virginia Regional...
Theory of Edge Detection D. Marr; E. Hildreth
Fiete, Ila
Theory of Edge Detection D. Marr; E. Hildreth Proceedings of the Royal Society of London. Series B on the image forms the basis for a physiological model of simple cells (see Marr & Ullman 1979
Edge-Based Image Compression with Homogeneous Diffusion
with the MarrHildreth operator followed by hys- teresis thresholding. Their locations are stored in a lossless of potential interest for image compression. One of the classical edge detectors is based on the Marr
TOWARD THE MINIMUM INNER EDGE DISTANCE OF THE HABITABLE ZONE
Zsom, Andras
We explore the minimum distance from a host star where an exoplanet could potentially be habitable in order not to discard close-in rocky exoplanets for follow-up observations. We find that the inner edge of the Habitable ...
Hong Kong : city of edges : South East Kowloon development
Chan, Wai-Kuen, 1968-
1997-01-01
Many extraordinary cities are developed along the edges of water into different directions. Yet, the city of Hong Kong has been formed along narrow strips of scarce flat-land around the harbor and from reclamations of ...
Leading Edge Spinning the Web of Cell Fate
Corces, Victor G.
Leading Edge Minireview Spinning the Web of Cell Fate Kevin Van Bortle1 and Victor G. Corces1,* 1 involved in spinning the web of cell fate. Chromatin at the Nuclear Lamina The nuclear lamina is a thin
Retail/commercial edges in the contemporary urban context
O'Neill, Brian Charles
1982-01-01
This thesis ascertains what morphological and functional characteristics are germane to retail edges. The work is structured around and supportive of an attitude that views social interaction as a vital and necessary ...
ORIGINAL PAPER Asymmetrical responses of forest and ``beyond edge''
Gratton, Claudio
, which were assumed representative of the respective communities. Logistic models of indicator species the forest edge and into the grassland more than the reverse, i.e. the effect was asymmetric. From these data
Highly dispersive photonic band-gap-edge optofluidic biosensors
Xiao, S; Xiao, Sanshui; Mortensen, Niels Asger
2006-01-01
Highly dispersive photonic band-gap-edge optofluidic biosensors are studied theoretically. We demonstrate that these structures are strongly sensitive to the refractive index of the liquid, which is used to tune dispersion of the photonic crystal. The upper frequency band-gap edge shifts about 1.8 nm for dn=0.002, which is quite sensitive. Results from transmission spectra agree well with those obtained from the band structure theory.
1 How (Not) to Protect Genomic Data Privacy in a Distributed Network: Using Trail Re-specific genomic data into clinical practice and research raises serious privacy concerns. Various systems have being disclosed, they lack formal proofs. In this paper, we study the erosion of privacy when genomic
Edge magnetotransport in graphene: A combined analytical and numerical study
Thomas Stegmann; Axel Lorke
2015-11-12
The current flow along the boundary of graphene stripes in a perpendicular magnetic field is studied theoretically by the nonequilibrium Green's function method. In the case of specular reflections at the boundary, the Hall resistance shows equidistant peaks, which are due to classical cyclotron motion. When the strength of the magnetic field is increased, anomalous resistance oscillations are observed, similar to those found in a nonrelativistic 2D electron gas [New. J. Phys. 15:113047 (2013)]. Using a simplified model, which allows to solve the Dirac equation analytically, the oscillations are explained by the interference between the occupied edge states causing beatings in the Hall resistance. A rule of thumb is given for the experimental observability. Furthermore, the local current flow in graphene is affected significantly by the boundary geometry. A finite edge current flows on armchair edges, while the current on zigzag edges vanishes completely. The quantum Hall staircase can be observed in the case of diffusive boundary scattering. The number of spatially separated edge channels in the local current equals the number of occupied Landau levels. The edge channels in the local density of states are smeared out but can be made visible if only a subset of the carbon atoms is taken into account.
Edge Temperature Gradient as Intrinsic Rotation Drive in AlcatorC...
Office of Scientific and Technical Information (OSTI)
Edge Temperature Gradient as Intrinsic Rotation Drive in AlcatorC-Mod Tokamak Plasmas Citation Details In-Document Search Title: Edge Temperature Gradient as Intrinsic Rotation...
Kuiper, James A; Krummel, John R; Hlava, Kevin J; Moore, H Robert; Orr, Andrew B; Schlueter, Scott O; Sullivan, Robert G; Zvolanek, Emily A
2014-03-25
As has been noted in many reports and publications, acquiring new or expanded rights-of-way for transmission is a challenging process, because numerous land use and land ownership constraints must be overcome to develop pathways suitable for energy transmission infrastructure. In the eastern U.S., more than twenty federally protected national trails (some of which are thousands of miles long, and cross many states) pose a potential obstacle to the development of new or expanded electricity transmission capacity. However, the scope of this potential problem is not well-documented, and there is no baseline information available that could allow all stakeholders to study routing scenarios that could mitigate impacts on national trails. This report, Electricity Transmission, Pipelines, and National Trails: An Analysis of Current and Potential Intersections on Federal Lands in the Eastern United States, was prepared by the Environmental Science Division of Argonne National Laboratory (Argonne). Argonne was tasked by DOE to analyze the footprint of the current network of National Historic and Scenic Trails and the electricity transmission system in the 37 eastern contiguous states, Alaska, and Hawaii; assess the extent to which national trails are affected by electrical transmission; and investigate the extent to which national trails and other sensitive land use types may be affected in the near future by planned transmission lines. Pipelines are secondary to transmission lines for analysis, but are also within the analysis scope in connection with the overall directives of Section 368 of the Energy Policy Act of 2005, and because of the potential for electrical transmission lines being collocated with pipelines. Based on Platts electrical transmission line data, a total of 101 existing intersections with national trails on federal land were found, and 20 proposed intersections. Transmission lines and pipelines are proposed in Alaska; however there are no locations that intersect national trails. Source data did not indicate any planned transmission lines or pipelines in Hawaii. A map atlas provides more detailed mapping of the topics investigated in this study, and the accompanying GIS database provides the baseline information for further investigating locations of interest. In many cases the locations of proposed transmission lines are not accurately mapped (or a specific route may not yet be determined), and accordingly the specific crossing locations are speculative. However since both national trails and electrical transmission lines are long linear systems, the characteristics of the crossings reported in this study are expected to be similar to both observed characteristics of the existing infrastructure provided in this report, and of the new infrastructure if these proposed projects are built. More focused study of these siting challenges is expected to mitigate some of potential impacts by choosing routes that minimize or eliminate them. The current study primarily addresses a set of screening-level characterizations that provide insights into how the National Trail System may influence the siting of energy transport facilities in the states identified under Section 368(b) of the Energy Policy Act of 2005. As such, it initializes gathering and beginning analysis of the primary environmental and energy data, and maps the contextual relationships between an important national environmental asset and how this asset intersects with energy planning activities. Thus the current study sets the stage for more in-depth analyses and data development activities that begin to solve key transmission siting constraints. Our recommendations for future work incorporate two major areas: (1) database development and analytics and (2) modeling and scenario analysis for energy planning. These recommendations provide a path forward to address key issues originally developed under the Energy Policy Act of 2005 that are now being carried forward under the Presidents Climate Action Plan.
of Chemical Engineering and Materials Science, UniVersity of Minnesota, Minneapolis, Minnesota 55455 Recei hydrated zirconia particles that decorate the edges of the sheets. The reaction does not go to completion
Oscillations of a Turbulent Jet Incident Upon an Edge
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. Large increases in Reynolds stress occur due to onset of the small-scale concentrations of vorticity immediately downstream of separation; substantial increases at locations further downstream arise from development of the large-scale vorticity concentrations.
Curvature of the QCD critical line with 2+1 HISQ fermions
Paolo Cea; Leonardo Cosmai; Alessandro Papa
2014-10-09
We present results on the curvature of the critical line of QCD with 2+1 HISQ fermions at nonzero temperature and quark density obtained by analytic continuation from imaginary chemical potentials. Monte Carlo simulations are performed by means of the MILC code, suitably modified to include a nonzero imaginary baryon chemical potential. We set the chemical potential at the same value for the three quark species and work on the line of constant physics with a light to strange mass ratio of 1/20 as determined in Ref.~\\cite{Bazavov:2011nk}.
Information content in $F(R)$ brane models with non-constant curvature
Correa, R A C; Dutra, A de Souza; da Rocha, Roldao; Menezes, R
2015-01-01
In this work we investigate the entropic information-measure in the context of braneworlds with non-constant curvature. The braneworld entropic information is studied for gravity modified by the squared of the Ricci scalar, besides the usual Einstein-Hilbert term. We showed that the minimum value of the brane configurational entropy provides a stricter bound on the parameter that is responsible for the $F(R)$ model to differ from the Einstein-Hilbert standard one. Our results are moreover consistent to a negative bulk cosmological constant.
Tungsten dust impact on ITER-like plasma edge
Smirnov, R. D. Krasheninnikov, S. I.; Pigarov, A. Yu.; Rognlien, T. D.
2015-01-15
The impact of tungsten dust originating from divertor plates on the performance of edge plasma in ITER-like discharge is evaluated using computer modeling with the coupled dust-plasma transport code DUSTT-UEDGE. Different dust injection parameters, including dust size and mass injection rates, are surveyed. It is found that tungsten dust injection with rates as low as a few mg/s can lead to dangerously high tungsten impurity concentrations in the plasma core. Dust injections with rates of a few tens of mg/s are shown to have a significant effect on edge plasma parameters and dynamics in ITER scale tokamaks. The large impact of certain phenomena, such as dust shielding by an ablation cloud and the thermal force on tungsten ions, on dust/impurity transport in edge plasma and consequently on core tungsten contamination level is demonstrated. It is also found that high-Z impurities provided by dust can induce macroscopic self-sustained plasma oscillations in plasma edge leading to large temporal variations of edge plasma parameters and heat load to divertor target plates.
Carbon K-edge Spectra of Carbonate Minerals
Brandes, J.; Wirick, S; Jacobsen, C
2010-01-01
Carbon K-edge X-ray spectroscopy has been applied to the study of a wide range of organic samples, from polymers and coals to interstellar dust particles. Identification of carbonaceous materials within these samples is accomplished by the pattern of resonances in the 280-320 eV energy region. Carbonate minerals are often encountered in the study of natural samples, and have been identified by a distinctive resonance at 290.3 eV. Here C K-edge and Ca L-edge spectra from a range of carbonate minerals are presented. Although all carbonates exhibit a sharp 290 eV resonance, both the precise position of this resonance and the positions of other resonances vary among minerals. The relative strengths of the different carbonate resonances also vary with crystal orientation to the linearly polarized X-ray beam. Intriguingly, several carbonate minerals also exhibit a strong 288.6 eV resonance, consistent with the position of a carbonyl resonance rather than carbonate. Calcite and aragonite, although indistinguishable spectrally at the C K-edge, exhibited significantly different spectra at the Ca L-edge. The distinctive spectral fingerprints of carbonates provide an identification tool, allowing for the examination of such processes as carbon sequestration in minerals, Mn substitution in marine calcium carbonates (dolomitization) and serpentinization of basalts.
Phosphorus K-edge XANES Spectroscopy of Mineral Standards
E Ingall; J Brandes; J Diaz; M de Jonge; D Paterson; I McNulty; C Elliott; P Northrup
2011-12-31
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.
Nano Res. 2011, 4(12): 124212471242 Chemical Versus Thermal Folding of Graphene Edges
Simons, Jack
Nano Res. 2011, 4(12): 124212471242 Chemical Versus Thermal Folding of Graphene Edges Ninghai Su dynamics (MD) simulations, we have investigated the kinetics of the graphene edge folding processV/Å (or about 120 meV per edge atom) for folding the edges of intrinsic clean single-layer graphene (SLG
Approximating Minimum-Power Edge-Covers and 2, 3-Connectivity Guy Kortsarz
Kortsarz, Guy
than edge-connectivity, as it models stations failures. Such power minimization problems were vastlyApproximating Minimum-Power Edge-Covers and 2, 3-Connectivity Guy Kortsarz Rutgers University a graph with edge costs, the power of a node is the maximum cost of an edge leaving it, and the power
Core Microturbulence and Edge MHD Interplay and Stabilization by Fast Ions in Tokamak Confined Plasmas
Curvature pressure in a cosmology with a tired-light redshift
David F. Crawford
1999-09-06
A hypothesis of curvature pressure is used to derive a static and stable cosmology with a tired-light redshift. The idea is that the high energy particles in the inter-galactic medium do not travel along geodesics because of the strong electrostatic forces. The result is a reaction back on the medium that is seen as an additional pressure. Combined with the explanation of the Hubble redshift as a gravitational interaction results in a static and stable cosmology. The predicted Hubble constant is 60.2 km/s/Mpc, the predicted background microwave temperature is 3 degrees and quasar luminosity functions and angular size distributions are shown to be consistent with the model. Since most observations that imply dark matter rely on redshift data it is argued that there is no dark matter. Observations of quasar absorption lines, supernovae light curves and the Butcher-Oemler effect are discussed. The curvature pressure is important for stellar structure and may explain the solar neutrino deficiency.
Composite polymer: Glass edge cladding for laser disks
Powell, H.T.; Wolfe, C.A.; Campbell, J.H.; Murray, J.E.; Riley, M.O.; Lyon, R.E.; Jessop, E.S.
1987-11-02
Large neodymium glass laser disks for disk amplifiers such as those used in the Nova laser require an edge cladding which absorbs at 1 micrometer. This cladding prevents edge reflections from causing parasitic oscillations which would otherwise deplete the gain. Nova now utilizes volume-absorbing monolithic-glass claddings which are fused at high temperature to the disks. These perform quite well but are expensive to produce. Absorbing glass strips are adhesively bonded to the edges of polygonal disks using a bonding agent whose index of refraction matches that of both the laser and absorbing glass. Optical finishing occurs after the strips are attached. Laser disks constructed with such claddings have shown identical gain performance to the previous Nova disks and have been tested for hundreds of shots without significant degradation. 18 figs.
Composite polymer-glass edge cladding for laser disks
Powell, Howard T. (Livermore, CA); Riley, Michael O. (San Ramon, CA); Wolfe, Charles R. (Palo Alto, CA); Lyon, Richard E. (Livermore, CA); Campbell, John H. (Livermore, CA); Jessop, Edward S. (Tracy, CA); Murray, James E. (Livermore, CA)
1989-01-01
Large neodymium glass laser disks for disk amplifiers such as those used in the Nova laser require an edge cladding which absorbs at 1 micrometer. This cladding prevents edge reflections from causing parasitic oscillations which would otherwise deplete the gain. Nova now utilizes volume-absorbing monolithic-glass claddings which are fused at high temperature to the disks. These perform quite well but are expensive to produce. Absorbing glass strips are adhesively bonded to the edges of polygonal disks using a bonding agent whose index of refraction matches that of both the laser and absorbing glass. Optical finishing occurs after the strips are attached. Laser disks constructed with such claddings have shown identical gain performance to the previous Nova disks and have been tested for hundreds of shots without significant degradation.
A survey of problems in divertor and edge plasma theory
Boozer, A. ); Braams, B.; Weitzner, H. . Courant Inst. of Mathematical Sciences); Cohen, R. ); Hazeltine, R. . Inst. for Fusion Studies); Hinton, F. ); Houlberg, W. (Oak
1992-12-22
Theoretical physics problems related to divertor design are presented, organized by the region in which they occur. Some of the open questions in edge physics are presented from a theoretician's point of view. After a cursory sketch of the fluid models of the edge plasma and their numerical realization, the following topics are taken up: time-dependent problems, non-axisymmetric effects, anomalous transport in the scrape-off layer, edge kinetic theory, sheath effects and boundary conditions in divertors, electric field effects, atomic and molecular data issues, impurity transport in the divertor region, poloidally localized power dissipation (MARFEs and dense gas targets), helium ash removal, and neutral transport. The report ends with a summary of selected problems of particular significance and a brief bibliography of survey articles and related conference proceedings.
A survey of problems in divertor and edge plasma theory
Boozer, A.; Braams, B.; Weitzner, H.; Cohen, R.; Hazeltine, R.; Hinton, F.; Houlberg, W.; Oktay, E.; Sadowski, W.; Post, D.; Sigmar, D.; Wootton, A.
1992-12-22
Theoretical physics problems related to divertor design are presented, organized by the region in which they occur. Some of the open questions in edge physics are presented from a theoretician`s point of view. After a cursory sketch of the fluid models of the edge plasma and their numerical realization, the following topics are taken up: time-dependent problems, non-axisymmetric effects, anomalous transport in the scrape-off layer, edge kinetic theory, sheath effects and boundary conditions in divertors, electric field effects, atomic and molecular data issues, impurity transport in the divertor region, poloidally localized power dissipation (MARFEs and dense gas targets), helium ash removal, and neutral transport. The report ends with a summary of selected problems of particular significance and a brief bibliography of survey articles and related conference proceedings.
Role of chemical termination in edge contact to graphene
Gao, Qun; Guo, Jing, E-mail: guoj@ufl.edu [Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida 32611 (United States)
2014-05-01
Edge contacts to graphene can offer excellent contact properties. Role of different chemical terminations is examined by using ab initio density functional theory and quantum transport simulations. It is found that edge termination by group VI elements O and S offers considerably lower contact resistance compared to H and group VII element F. The results can be understood by significantly larger binding energy and shorter binding distance between the metal contact and these group VI elements, which results in considerably lower interface potential barrier and larger transmission. The qualitative conclusion applies to a variety of contact metal materials.
Predicting the Performance of Edge Seal Materials for PV (Presentation)
Kempe, M.; Panchagade, D.; Dameron, A.; Reese, M.
2012-03-01
Edge seal materials were evaluated using a 100-nm film of Ca deposited on glass and laminated to another glass substrate. As moisture penetrates the package it converts the Ca metal to transparent CaOH2 giving a clear indication of the depth to which moisture has entered. Using this method, we have exposed test samples to a variety of temperature and humidity conditions ranging from 45C and 10% RH up to 85C and 85% RH, to ultraviolet radiation and to mechanical stress. We are able to show that edge seal materials are capable of keeping moisture away from sensitive cell materials for the life of a module.
Flexible edge seal for vacuum insulating glazing units
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.
Industries of the Future: Creating a Sustainable Technology Edge
Glatt, S. L.
2000-01-01
OF THE FUTURE: Creating A Sustainable Technology Edge Sandra L. Glatt Office of Industrial Technologies Energy Efficiency and Renewable Energy U. S. Department of Energy 55 ESL-IE-00-04-10 Proceedings from the Twenty-second National Industrial Energy....S, Department of Energy Industries of the Future: Creating a Sustainable Technology Edge . cUn' OFwlOd CCooI .. LPG .Eleclric~ CNI!hnIG. AgriclAtll'e Mining A1uminu",J Totll1* kldutb't.1 Conllomption: :W, 111 TrtIlion 8tus Forest E"~ ?'913 1976...
Wobbrock, Jacob O.
EdgeWrite: A New Text Entry Technique Designed for Stability Page 1 EdgeWrite: A New Text Entry of cost, complexity, and maintenance (2). If we had a text entry technique that could be used that benefits one group may therefore benefit the other. #12;EdgeWrite: A New Text Entry Technique Designed
Journey to the edge of time: The GREAT mission
Neil J. Cornish; David N. Spergel; Charles L. Bennett
2002-01-31
We are surrounded by radiation that originated from the big bang. It has traveled to us from the farthest reaches of the Universe, carrying with it an unaltered record of the beginning of time and space. The radiation is in the form of gravitational waves - propagating ripples in the curvature of spacetime. We describe a mission to detect these Gravitational Echos Across Time (GREAT) that would open up a new window on the very early universe. By studying the gravitational echoes of the big bang we will gain insight into the fundamental structure of matter, gravity, and how the Universe formed.
Stachowiak, Jeanne C.; Hayden, Carl C.; Negrete, Oscar A.; Davis, Ryan Wesley; Sasaki, Darryl Yoshio
2013-10-01
Pathogenic viruses are a primary threat to our national security and to the health and economy of our world. Effective defense strategies to combat viral infection and spread require the development of understanding of the mechanisms that these pathogens use to invade the host cell. We present in this report results of our research into viral particle recognition and fusion to cell membranes and the role that protein affinity and confinement in lipid domains plays in membrane curvature in cellular fusion and fission events. Herein, we describe 1) the assembly of the G attachment protein of Nipah virus using point mutation studies to define its role in viral particle fusion to the cell membrane, 2) how lateral pressure of membrane bound proteins induce curvature in model membrane systems, and 3) the role of membrane curvature in the selective partitioning of molecular receptors and specific affinity of associated proteins.
Shimada, Hiroyuki Minami, Hirotake; Okuizumi, Naoto; Sakuma, Ichiro; Ukai, Masatoshi; Fujii, Kentaro; Yokoya, Akinari; Fukuda, Yoshihiro; Saitoh, Yuji
2015-05-07
X-ray absorption near edge structure (XANES) was measured at energies around the N K-edge of the pyrimidine-containing nucleotides, cytidine 5?-monophosphate (CMP), 2?-deoxythymidine 5?-monophosphate (dTMP), and uridine 5?-monophosphate (UMP), in aqueous solutions and in dried films under various pH conditions. The features of resonant excitations below the N K-edge in the XANES spectra for CMP, dTMP, and UMP changed depending on the pH of the solutions. The spectral change thus observed is systematically explained by the chemical shift of the core-levels of N atoms in the nucleobase moieties caused by structural changes due to protonation or deprotonation at different proton concentrations. This interpretation is supported by the results of theoretical calculations using density functional theory for the corresponding nucleobases in the neutral and protonated or deprotonated forms.
Leading Edge Antiviral Strategies: Building a Better Defense
Ferguson, Andrew
Leading Edge Select Antiviral Strategies: Building a Better Defense Viruses are a widespread demand. In this Select, we look at recent papers that are helping to advance antiviral research that are surrounded by a lipid bilayer that is needed for cellular entry and infec- tivity (enveloped), and those
RESEARCH ARTICLE Living on the edge: quantifying the structure
Malhi, Yadvinder
House, Abingdon Road, Tubney, Abingdon OX13 5QL, UK E. M. Slade Spatial Foodweb Ecology Group microclimatic and biological changes at the forest edge. If we are to rigorously assess the ecological impacts estimates can be combined with ecological response functions, to allow us to generate biologically
Poster Abstract: Towards Active Measurements of Edge Network Outages
Heidemann, John
Poster Abstract: Towards Active Measurements of Edge Network Outages Lin Quan John Heidemann Yuri-to-end reachability is a fundamental service of the Internet. We study net- work outages caused by natural disasters [2,5], and political upheavals [8]. We propose a new approach to outage detection using active
Fluctuations from edge defects in superconducting resonators A. Megrant,1
Martinis, John M.
Fluctuations from edge defects in superconducting resonators C. Neill,1 A. Megrant,1 R. Barends,1 August 2013) Superconducting resonators, used in astronomy and quantum computation, couple strongly to microscopic two-level defects. We monitor the microwave response of superconducting resonators and observe
SciDAC-Center for Plasma Edge Simulation
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. ItĆ¢Ā?Ā?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.
FACETS: Framework Application for Core-Edge Transport Simulations
-institutional main project: Tech-X (Physics, CS/AM); LLNL (Physics, CS/AM); PPPL (Physics); ANL (CS/AM); UCSD (Physics); CSU (AM); ORNL (CS, perf); ParaTools (CS, perf) · Appended SAP: GA, ORNL · Advisory: Columbia transitions · Core is a collisionless, 1D transport system with local, only-cross-surface fluxes · Edge
On Plane Bipartite Graphs without Fixed Edges Khaled Salem*
Klavzar, Sandi
cycle. Randi [12, 13] used alternating cycles (or conjugated circuits) to estimate resonance energies face is an alternating cycle. Moreover, a polyhex fragment has no fixed edges if and only if the boundaries of its infinite face and the non-hexagonal finite faces are alternating cycles. These results
Edge stability and transport control with resonant magnetic perturbations in
Loss, Daniel
ARTICLES Edge stability and transport control with resonant magnetic perturbations in collisionless, California 92186-5608, USA 2 University of California, San Diego, California 92093-0417, USA 3 Lawrence Livermore National Laboratory, Livermore, California 94551-0808, USA 4 Association EURATOM-CEA, CEA
SciDAC - Center for Plasma Edge Simulation - Project Summary
Parker, Scott
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.
The rheology and processing of edge sheared colloidal polymer opals
Wong, Hon Sum; Mackley, Malcolm Butler, Simon; Baumberg, Jeremy; Snoswell, David; Finlayson, Chris; Zhao, Qibin
2014-03-15
This paper is concerned with the rheology and processing of solvent-free core shell polymer opals that consist of a soft outer shell grafted to hard colloidal polymer core particles. Strong iridescent colors can be produced by shearing the material in a certain way that causes the initially disordered spheres to rearrange into ordered crystalline structures and produce colors by diffraction and interference of multiple light scattering, similar to gemstone opals. The basic linear viscoelastic rheology of a polymer opal sample was determined as a function of temperature, and the material was found to be highly viscoelastic at all tested temperatures. A Cambridge multipass rheometer was specifically modified in order to make controlled mechanical measurements of initially disordered polymer opal tapes that were sandwiched between protective polyethylene terephthalate sheets. Axial extension, simple shear, and a novel edge shearing geometry were all evaluated, and multiple successive experiments of the edge shearing test were carried out at different temperatures. The optical development of colloidal ordering, measured as optical opalescence, was quantified by spectroscopy using visible backscattered light. The development of opalescence was found to be sensitive to the geometry of deformation and a number of process variables suggesting a complex interaction of parameters that caused the opalescence. In order to identify aspects of the deformation mechanism of the edge shearing experiment, a separate series of in situ optical experiments were carried out and this helped indicate the extent of simple shear generated with each edge shear deformation. The results show that strong ordering can be induced by successive edge shearing deformation. The results are relevant to polymer opal rheology, processing, and mechanisms relating to ordering within complex viscoelastic fluids.
Curvature-Induced Bunch Self-Interaction for an Energy-Chirped Bunch in Magnetic Bends
Rui Li
2006-01-04
The curvature-induced bunch collective interaction in magnetic bends can be studied using effective forces in the canonical formulation of the coherent synchrotron radiation (CSR) effect. In this paper, for an electron distribution moving ultrarelativistically in a bending system, the dynamics of a particle in the electron distribution is derived from the Hamiltonian of the particle in terms of the bunch internal coordinates. The consequent Vlasov equation manifests explicitly how the phase space distribution is perturbed by the effective CSR forces. In particular, we study the impact of an initial linear energy chirp of the bunch on the behavior of the effective longitudinal CSR force, which arises due to the modification of the retardation relation as a result of the energy-chirping-induced longitudinal-horizontal correlation of the bunch distribution (bunch tilt) in dispersive regions.
The importance of ion size and electrode curvature on electrical double layers in ionic liquids
Feng, G.; Qiao, R.; Huang, J; Dai, S.; Sumpter, B. G.; Meunier, V.
2011-01-01
Room-temperature ionic liquids (ILs) are an emerging class of electrolytes for supercapacitors. We investigate the effects of ion size and electrode curvature on the electrical double layers (EDLs) in two ILs 1-butyl-3-methylimidazolium chloride [BMIM][Cl] and 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF{sub 6}], using a combination of molecular dynamics (MD) and quantum density functional theory (DFT) simulations. The sizes of the counter-ion and co-ion affect the ion distribution and orientational structure of EDLs. The EDL capacitances near both planar and cylindrical electrodes were found to follow the order: [BMIM][Cl] (near the positive electrode) > [BMIM][PF{sub 6}] (near the positive electrode) ? [BMIM][Cl] (near the negative electrode) ? [BMIM][PF{sub 6}] (near the negative electrode). The EDL capacitance was also found to increase as the electrode curvature increases. These capacitance data can be fit to the Helmholtz model and the recently proposed exohedral electrical double-cylinder capacitor (xEDCC) model when the EDL thickness is properly parameterized, even though key features of the EDLs in ILs are not accounted for in these models. To remedy the shortcomings of existing models, we propose a Multiple Ion Layers with Overscreening (MILO) model for the EDLs in ILs that takes into account two critical features of such EDLs, i.e., alternating layering of counter-ions and co-ions and charge overscreening. The capacitance computed from the MILO model agrees well with the MD prediction. Although some input parameters of the MILO model must be obtained from MD simulations, the MILO model may provide a new framework for understanding many important aspects of EDLs in ILs (e.g., the variation of EDL capacitance with the electrode potential) that are difficult to interpret using classical EDL models and experiments.
The Importance of Ion Size and Electrode Curvature on Electrical Double Layers in Ionic Liquids
Feng, Guang; Qiao, Rui; Huang, Jingsong; Dai, Sheng; Sumpter, Bobby G; Meunier, Vincent
2010-01-01
Room-temperature ionic liquids (ILs) are an emerging class of electrolytes for supercapacitors. We investigate the effects of ion size and electrode curvature on the electrical double layers (EDLs) in two ILs 1-butyl-3-methylimidazolium chloride [BMIM][Cl] and 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF(6)], using a combination of molecular dynamics (MD) and quantum density functional theory (DFT) simulations. The sizes of the counter-ion and co-ion affect the ion distribution and orientational structure of EDLs. The EDL capacitances near both planar and cylindrical electrodes were found to follow the order: [BMIM][Cl] (near the positive electrode) > [BMIM][PF(6)] (near the positive electrode) {approx} [BMIM][Cl] (near the negative electrode) {approx} [BMIM][PF(6)] (near the negative electrode). The EDL capacitance was also found to increase as the electrode curvature increases. These capacitance data can be fit to the Helmholtz model and the recently proposed exohedral electrical double-cylinder capacitor (xEDCC) model when the EDL thickness is properly parameterized, even though key features of the EDLs in ILs are not accounted for in these models. To remedy the shortcomings of existing models, we propose a 'Multiple Ion Layers with Overscreening' (MILO) model for the EDLs in ILs that takes into account two critical features of such EDLs, i.e., alternating layering of counter-ions and co-ions and charge overscreening. The capacitance computed from the MILO model agrees well with the MD prediction. Although some input parameters of the MILO model must be obtained from MD simulations, the MILO model may provide a new framework for understanding many important aspects of EDLs in ILs (e.g., the variation of EDL capacitance with the electrode potential) that are difficult to interpret using classical EDL models and experiments.
Chung, Moo K.
smoothing. A similar approach has been taken in [6]. Methods A group of 2D mid sagittal cross section images of predefined Witelson par- tition [5] as a morphometric measure but other shape metrics have not been splines to estimate the first and second derivatives to compute the curvature: min g 1 n n j=1 [Yj - g
Haller, Gary L.
IEEE TRANSACTIONS ON ROBOTICS, VOL. 28, NO. 4, AUGUST 2012 761 The Smooth Curvature Model: An Efficient Representation of EulerBernoulli Flexures as Robot Joints Lael U. Odhner, Member, IEEE, and Aaron M. Dollar, Member, IEEE Abstract--This paper presents a new method to produce compu- tationally
David F. Crawford
1998-03-02
A hypothesis is presented that electromagnetic forces that prevent ions from following geodesics results in a curvature pressure that is very important in astrophysics. It may partly explain the solar neutrino deficiency and it may be the engine that drives astrophysical jets. However its most important consequence is that it leads to a static and stable cosmology using general relativity without a cosmological constant.
Taylor, Stuart Glynn
2013-01-01
included a carbon fiber spar cap, with a fiberglass shellInner WASP No Trailing Edge Spar Cap Low- pressure side A;0leading edge, trailing edge, spar cap, and root area of the
Edge-states ferromagnetism of WS{sub 2} nanosheets
Huo, Nengjie; Li, Yan; Kang, Jun; Li, Renxiong; Xia, Qinglin; Li, Jingbo
2014-05-19
The multilayer WS{sub 2} nanosheets prepared from WO{sub 3} nanowires exhibit strong ferromagnetic behavior with saturation magnetization (M{sub S}) of 0.0058?emu/g and coercive field (H{sub C}) of 92?Oe at room temperature. By decreasing the temperature down to 3?K the H{sub c} is increased up to 1115 Oe, revealing the existence of long-range magnetic ordering. Density functional theory spin-polarized calculations predict that strong ferromagnetic moments in WS{sub 2} nanosheets are attributed to the zigzag edge sulphur S and tungsten W atoms. Our findings also suggest that the WS{sub 2} nanosheets with a high density of edge spins could be used to fabricate spintronics devices, which are circuits utilizing the spin of the electron to process and store information.
The rate of entropy increase at the edge of chaos
V. Latora; M. Baranger; A. Rapisarda; C. Tsallis
2000-07-07
Under certain conditions, the rate of increase of the statistical entropy of a simple, fully chaotic, conservative system is known to be given by a single number, characteristic of this system, the Kolmogorov-Sinai entropy rate. This connection is here generalized to a simple dissipative system, the logistic map, and especially to the chaos threshold of the latter, the edge of chaos. It is found that, in the edge-of-chaos case, the usual Boltzmann-Gibbs-Shannon entropy is not appropriate. Instead, the non-extensive entropy $S_q\\equiv \\frac{1-\\sum_{i=1}^W p_i^q}{q-1}$, must be used. The latter contains a parameter q, the entropic index which must be given a special value $q^*\
Nuclear Star Clusters in Edge-on Galaxies
Anil C. Seth; Julianne J. Dalcanton; Paul W. Hodge; Victor P. Debattista
2006-06-02
From observations of edge-on, late-type galaxies, we present morphological evidence that some nuclear star clusters have experienced in situ star formation. We find three nuclear clusters that, viewed from the edge-on perspective, have both a compact disk-like component and a spheroidal component. In each cluster, the disk components are closely aligned with the major axis of the host galaxy and have bluer colors than the spheroidal components. We spectroscopically verify that one of the observed multiple component clusters has multiple generations of stars. These observations lead us to suggest a formation mechanism for nuclear star clusters, in which stars episodically form in compact nuclear disks, and then lose angular momentum, eventually forming an older spheroid.
Hot compression process for making edge seals for fuel cells
Dunyak, Thomas J. (Blacksburg, VA); Granata, Jr., Samuel J. (South Greensburg, PA)
1994-01-01
A hot compression process for forming integral edge seals in anode and cade assemblies wherein the assemblies are made to a nominal size larger than a finished size, beads of AFLAS are applied to a band adjacent the peripheral margins on both sides of the assemblies, the assemblies are placed in a hot press and compressed for about five minutes with a force sufficient to permeate the peripheral margins with the AFLAS, cooled and cut to finished size.
Rimmed and edge thickened stodola shaped flywheel. [Patent application
Kulkarni, S.V.; Stone, R.G.
1980-09-24
A flywheel is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel has a body composed of essentially planar isotropic high strength material. The flywheel body is enclosed by a rim of circumferentially wound fiber embedded in resin. The rim promotes flywheel safety and survivability. The flywheel has a truncated and edge thickened Stodola shape designed to optimize system mass and energy storage capability.
River Edge, New Jersey: Energy Resources | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onRAPID/Geothermal/Exploration/ColoradoRemsenburg-Speonk, New York:Virginia:Riva, Maryland: Energy Resources Jump to:Edge,
Loop formation in graphitic nanoribbon edges using furnace heating or Joule heating
Jia, Xiaoting
Here the authors report the use of either furnace heating or Joule heating to pacify the exposed graphene edges by loop formation in a novel graphitic nanoribbonmaterial, grown by chemical vapor deposition. The edge energy ...
López-Barrera, Fabiola
Forest edges created by scattered-patch clear-cutting have become a common landscape feature in tropical montane forests, including pine-oak and evergreen cloud forests. Forest-edge-pasture gradients were characterised ...
Waveguiding at the Edge of a Three-Dimensional Photonic Crystal
Joannopoulos, John D.
We find that electromagnetic waves can be guided at the edge of a three-dimensional photonic crystal in air. When the waveguide is defined by the intersection of two surface planes, the edge modes are associated with the ...
Statistical control and experimental design for edge bead reduction in laminating process
Fan, Huangjia (Francis Huangjia)
2010-01-01
Edge bead formation is a well-known phenomenon typically happening in the lamination due to the physics of this process. It causes the defect of high edge observed in the carton roll after the laminated carton sheets are ...
Theory of nitrogen doping of carbon nanoribbons: Edge effects
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Jiang, Jie; Turnbull, Joseph; Lu, Wenchang; Oak Ridge National Lab.; Boguslawski, Piotr; Univ. of Warsaw; Bernholc, J.; Oak Ridge National Lab.
2012-01-01
Nitrogen doping of a carbon nanoribbon is profoundly affected by its one-dimensional character, symmetry, and interaction with edge states. Using state-of-the-art ab initio calculations, including hybrid exact-exchange density functional theory, we find that, for N-doped zigzag ribbons, the electronic properties are strongly dependent upon sublattice effects due to the non-equivalence of the two sublattices. For armchair ribbons, N-doping effects are different depending upon the ribbon family: for families 2 and 0, the N-induced levels are in the conduction band, while for family 1 the N levels are in the gap. In zigzag nanoribbons, nitrogen close to the edge is amore »deep center, while in armchair nanoribbons its behavior is close to an effective-mass-like donor with the ionization energy dependent on the value of the band gap. In chiral nanoribbons, we find strong dependence of the impurity level and formation energy upon the edge position of the dopant, while such site-specificity is not manifested in the magnitude of the magnetization.« less
A knife-edge array field emission cathode
Lee, B.
1994-08-01
many cathode applications require a new type of cathode that is able to produce short pulsed electron beams at high emission current. Gated field emitter arrays of micrometer size are recognized as candidates to meet this need and have become the research focus of vacuum microelectronics. Existing fabrication methods produce emitters that are limited either in frequency response or in current emission. One reason is that the structure of these emitters are not sufficiently optimized. In this study, the author investigated the factors that affect the performance of field emitters. An optimum emitter structure, the knife-edge field emitter array, was developed from the analysis. Large field enhancement factor, large effective emission area, and small emitter capacitance are the advantages of the structure. The author next explored various options of fabricating the knife-edge emitter structure. He proposed a unique thin film process procedure and developed the fabrication techniques to build the emitters on (110) silicon wafers. Data from the initial cathode tests showed very low onset voltages and Fowler-Nordheim type emission. Emission simulation based on the fabricated emitter structure indicated that the knife-edge emitter arrays have the potential to produce high performance in modulation frequency and current emission. Several fabrication issues that await further development are discussed and possible solutions are suggested.
van Vliet, Lucas J.
L.J. van Vliet and P.W. Verbeek, Curvature and bending energy in digitized 2D and 3D images, in-1410. Curvature and Bending Energy in Digitized 2D and 3D Images Lucas J. van Vliet and Piet W. Verbeek Pattern. In this paper we estimate object curvature directly from a properly sampled gray- scale image using 2D isotropic
van Vliet, Lucas J.
L.J. van Vliet and P.W. Verbeek, Curvature and bending energy in digitized 2D and 3D images, in1410. Curvature and Bending Energy in Digitized 2D and 3D Images Lucas J. van Vliet and Piet W. Verbeek Pattern. In this paper we estimate object curvature directly from a properly sampled gray scale image using 2D isotropic
Curvature-induced cross-hatched order in two-dimensional semiflexible polymer networks
Cyril Vrusch; Cornelis Storm
2015-07-14
A recurring motif in the organization of biological tissues are networks of long, fibrillar protein strands effectively confined to cylindrical surfaces. Often, the fibers in such curved, quasi-2D geometries adopt a characteristic order: the fibers wrap around the central axis at an angle which varies with radius and, in several cases, is strongly bimodally distributed. In this Letter, we investigate the general problem of a 2D crosslinked network of semiflexible fibers confined to a cylindrical substrate, and demonstrate that in such systems the trade-off between bending and stretching energies, very generically, gives rise to cross-hatched order. We discuss its general dependency on the radius of the confining cylinder, and present an intuitive model that illustrates the basic physical principle of curvature-induced order. Our findings shed new light on the potential origin of some curiously universal fiber orientational distributions in tissue biology, and suggests novel ways in which synthetic polymeric soft materials may be instructed or programmed to exhibit preselected macromolecular ordering.
Feynman-like rules for calculating n-point correlators of the primordial curvature perturbation
Valenzuela-Toledo, César A.; Rodrķguez, Yeinzon; Almeida, Juan P. Beltrįn E-mail: yeinzon.rodriguez@uan.edu.co
2011-10-01
A diagrammatic approach to calculate n-point correlators of the primordial curvature perturbation ? was developed a few years ago following the spirit of the Feynman rules in Quantum Field Theory. The methodology is very useful and time-saving, as it is for the case of the Feynman rules in the particle physics context, but, unfortunately, is not very well known by the cosmology community. In the present work, we extend such an approach in order to include not only scalar field perturbations as the generators of ?, but also vector field perturbations. The purpose is twofold: first, we would like the diagrammatic approach (which we would call the Feynman-like rules) to become widespread among the cosmology community; second, we intend to give an easy tool to formulate any correlator of ? for those cases that involve vector field perturbations and that, therefore, may generate prolonged stages of anisotropic expansion and/or important levels of statistical anisotropy. Indeed, the usual way of formulating such correlators, using the Wick's theorem, may become very clutter and time-consuming.
Giuseppe Congedo
2015-04-24
The measurement of frequency shifts for light beams exchanged between two test masses nearly in free fall is at the heart of gravitational wave detection. It is envisaged that the derivative of the frequency shift is in fact limited by differential forces acting on those test masses. We calculate the derivative of the frequency shift with a fully covariant, gauge-independent and coordinate-free method. This method is general and does not require a congruence of nearby beams' null geodesics as done in previous work. We show that the derivative of the parallel transport is the only means by which gravitational effects shows up in the frequency shift. This contribution is given as an integral of the Riemann tensor --the only physical observable of curvature-- along the beam's geodesic. The remaining contributions are: the difference of velocities, the difference of non-gravitational forces, and finally fictitious forces, either locally at the test masses or non-locally integrated along the beam's geodesic. As an application relevant to gravitational wave detection, we work out the frequency shift in the local Lorentz frame of nearby geodesics.
RNA regulatory networks diversified through curvature of the PUF protein scaffold
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Wilinski, Daniel; Qiu, Chen; Lapointe, Christopher P.; Nevil, Markus; Campbell, Zachary T.; Tanaka Hall, Traci M.; Wickens, Marvin
2015-09-14
Proteins bind and control mRNAs, directing their localization, translation and stability. Members of the PUF family of RNA-binding proteins control multiple mRNAs in a single cell, and play key roles in development, stem cell maintenance and memory formation. Here we identified the mRNA targets of a S. cerevisiae PUF protein, Puf5p, by ultraviolet-crosslinking-affinity purification and high-throughput sequencing (HITS-CLIP). The binding sites recognized by Puf5p are diverse, with variable spacer lengths between two specific sequences. Each length of site correlates with a distinct biological function. Crystal structures of Puf5pRNA complexes reveal that the protein scaffold presents an exceptionally flat and extendedmore »interaction surface relative to other PUF proteins. In complexes with RNAs of different lengths, the protein is unchanged. A single PUF protein repeat is sufficient to induce broadening of specificity. Changes in protein architecture, such as alterations in curvature, may lead to evolution of mRNA regulatory networks.« less
Strong transmission and reflection of edge modes in bounded photonic graphene
Ablowitz, Mark J
2015-01-01
The propagation of linear and nonlinear edge modes in bounded photonic honeycomb lattices formed by an array of rapidly varying helical waveguides is studied. These edge modes are found to exhibit strong transmission (reflection) around sharp corners when the dispersion relation is topologically nontrivial (trivial), and can also remain stationary. An asymptotic theory is developed that establishes the presence (absence) of edge states on all four sides, including in particular armchair edge states, in the topologically nontrivial (trivial) case. In the presence of topological protection, nonlinear edge solitons can persist over very long distances.
Kelley, Edward Madison
1969-01-01
A SURVEY OF IDEAL FLUID PRO~ THEORIES AND A STUIE OP THE EFFECTS OF AERODYNAMIC PRO~ LOADING ON TRAILING VORTEX INDUCED VELOCITY AND THRUST A Thesis EDWARD MADISON ~ Suhmitted to the Graduate College of Texas A&M University in Partial... VELOCITY AND THRUST A Thesis by EDWARD MADISON HELLEY Approsed as to sty1e and content 'by: Head of epartment i%. mbe August 1969 111 ABSTRACT A Survey of Ideal Fluid Propeller Theories and a Study of the Ei'fects of Aerodynamic Propeller...
Long Du; Yong-Long Wang; Guang-Zhen Kang; Xiao-Jun Liu; Hong-Shi Zong
2014-11-26
We derive the curvature induced quantum-mechanical potential of a neutral spinless particle constrained to move on a surface of revolution. Using the thin-layer quantization scheme, we decompose the tangent component of the Schr\\"odinger equation from the transverse component. The tangent Schr\\"odinger equation is separated into angular and axial direction in cylindrical coordinate. The exactly solvable model with the shape of truncated cone is investigated and its geometrical induced states are given analytically. With hard wall boundary condition, we find that energy levels and energy differences decrease monotonically with raising the height and generatrix slope of the geometry. Moreover, particles possessing higher kinetic energy tends to occupy the place with greater curvature. These results do good favor to concerned nano-structure experiment.
Krishan Rajaratnam; Raymond G. McLenaghan
2014-12-11
We study concircular tensors in spaces of constant curvature and then apply the results obtained to the problem of the orthogonal separation of the Hamilton-Jacobi equation on these spaces. Any coordinates which separate the geodesic Hamilton-Jacobi equation are called separable. Specifically for spaces of constant curvature, we obtain canonical forms of concircular tensors modulo the action of the isometry group, we obtain the separable coordinates induced by irreducible concircular tensors, and we obtain warped products adapted to reducible concircular tensors. Using these results, we show how to enumerate the isometrically inequivalent orthogonal separable coordinates, construct the transformation from separable to Cartesian coordinates, and execute the Benenti-Eisenhart-Kalnins-Miller (BEKM) separation algorithm for separating natural Hamilton-Jacobi equations.
Tourdot, Richard W; Baumgart, Tobias; Radhakrishnan, Ravi
2015-01-01
We investigate the phenomenon of protein induced tubulation of lipid bilayer membranes within a continuum framework using Monte Carlo simulations coupled with the Widom insertion technique to compute excess chemical potentials. Tubular morphologies are spontaneously formed when the density and the curvature-field strength of the membrane bound proteins exceed their respective thresholds and this transition is marked by a sharp drop in the excess chemical potential. We find that the planar to tubular transition can be described by a micellar model and that the corresponding free energy barrier increases with increase in the curvature-field strength, (i.e. of protein-membrane interactions), and also with increase in membrane tension.
Feng, Guang; Jiang, Deen; Cummings, Peter T
2012-01-01
Recent experiments have revealed that onion-like carbons (OLCs) offer high energy density and charging/discharging rates when used as the electrodes in supercapacitors. To understand the physical origin of this phenomenon, molecular dynamics simulations were performed for a room-temperature ionic liquid near idealized spherical OLCs with radii ranging from 0.356 to 1.223 nm. We find that the surface charge density increases almost linearly with the potential applied on electric double layers (EDLs) near OLCs. This leads to a nearly flat shape of the differential capacitance versus the potential, unlike the bell or camel shape observed on planar electrodes. Moreover, our simulations reveal that the capacitance of EDLs on OLCs increases with the curvature or as the OLC size decreases, in agreement with experimental observations. The curvature effect is explained by dominance of charge overscreening over a wide potential range and increased ion density per unit area of electrode surface as the OLC becomes smaller.
Edge coating apparatus with movable roller applicator for solar cell substrates
Pavani, Luca; Abas, Emmanuel
2012-12-04
A non-contact edge coating apparatus includes an applicator for applying a coating material on an edge of a solar cell substrate and a control system configured to drive the applicator. The control system may drive the applicator along an axis to maintain a distance with an edge of the substrate as the substrate is rotated to have the edge coated with a coating material. The applicator may include a recessed portion into which the edge of the substrate is received for edge coating. For example, the applicator may be a roller with a groove. Coating material may be introduced into the groove for application onto the edge of the substrate. A variety of coating materials may be employed with the apparatus including hot melt ink and UV curable plating resist.
Interacting spins and holes in zigzag edge nanographene
Dutta, Sudipta; Wakabayashi, Katsunori
2013-12-04
We have investigated charge and spin gap properties of zigzag edge graphene nanoribbons (ZGNRs) modeled within Hubbard Hamiltonian with onsite electron-electron interaction using semi-empirical many-body configuration interaction (CI) method. The charge gap behavior resembles the mean-field results, showing minima near Dirac point. We have observed unprecedented gap-less spin excitations over the flat band region. Moreover, doping the ZGNRs with holes reduces both the charge and spin gaps, inducing metallic and magnetic behavior, which can be exploited to fabricate spintronic devices.
Growing Cutting-edge X-ray Optics
Ray Conley
2013-07-17
Ever imagined that an Xbox controller could help open a window into a world spanning just one billionth of a meter? Brookhaven Lab's Ray Conley grows cutting-edge optics called multilayer Laue lenses (MLL) one atomic layer at a time to focus high-energy x-rays to within a single nanometer. To achieve this focusing feat, Ray uses a massive, custom-built atomic deposition device, an array of computers, and a trusty Xbox controller. These lenses will be deployed at the Lab's National Synchrotron Light Source II, due to begin shining super-bright light on pressing scientific puzzles in 2015
Low-temperature random matrix theory at the soft edge
Edelman, Alan; Persson, Per-Olof; Sutton, Brian D.
2014-06-15
Low temperature random matrix theory is the study of random eigenvalues as energy is removed. In standard notation, ? is identified with inverse temperature, and low temperatures are achieved through the limit ? ? ?. In this paper, we derive statistics for low-temperature random matrices at the soft edge, which describes the extreme eigenvalues for many random matrix distributions. Specifically, new asymptotics are found for the expected value and standard deviation of the general-? Tracy-Widom distribution. The new techniques utilize beta ensembles, stochastic differential operators, and Riccati diffusions. The asymptotics fit known high-temperature statistics curiously well and contribute to the larger program of general-? random matrix theory.
The edge of supersymmetry: Stability walls in heterotic theory
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Anderson, Lara B.; Gray, James; Lukas, Andre; Ovrut, Burt
2009-05-15
We explicitly describe, in the language of four-dimensional N = 1 supersymmetric field theory, what happens when the moduli of a heterotic Calabi-Yau compactification change so as to make the internal non-Abelian gauge fields non-supersymmetric. At the edge of the region in Kähler moduli space where supersymmetry can be preserved, an additional anomalous U(1) gauge symmetry appears in the four-dimensional theory. The D-term contribution to the scalar potential associated to this U(1) attempts to force the system back into a supersymmetric configuration and provides a consistent low-energy description of gauge bundle stability.
Scaling laws governing the roughness of the swash edge line
Ed. Bormashenko; A. Musin; R. Grynuov
2014-02-23
The physics of swash i.e. a layer of water that washes up on the beach after an incoming wave has broken is complicated and intriguing. It includes perplexed hydrodynamic and sediment transport events. In our paper we address to the roughness of the moving swash boundary at which a beach, water and air meet. We treat the behavior of this boundary as an interfacial phenomenon, without going into details of formation of edge waves and beach cusps, covered broadly in literature. This "crude" approach turns out to be productive and revealing the resemblance of the swash line with a broad diversity of effects arising from the random pinning of moving boundaries.
Scaling laws governing the roughness of the swash edge line
Bormashenko, Ed; Grynuov, R
2014-01-01
The physics of swash i.e. a layer of water that washes up on the beach after an incoming wave has broken is complicated and intriguing. It includes perplexed hydrodynamic and sediment transport events. In our paper we address to the roughness of the moving swash boundary at which a beach, water and air meet. We treat the behavior of this boundary as an interfacial phenomenon, without going into details of formation of edge waves and beach cusps, covered broadly in literature. This "crude" approach turns out to be productive and revealing the resemblance of the swash line with a broad diversity of effects arising from the random pinning of moving boundaries.
Edge Detection, Cosmic Strings and the South Pole Telescope
Andrew Stewart; Robert Brandenberger
2009-01-07
We develop a method of constraining the cosmic string tension $G\\mu$ which uses the Canny edge detection algorithm as a means of searching CMB temperature maps for the signature of the Kaiser-Stebbins effect. We test the potential of this method using high resolution, simulated CMB temperature maps. By modeling the future output from the South Pole Telescope project (including anticipated instrumental noise), we find that cosmic strings with $G\\mu > 5.5\\times10^{-8}$ could be detected.
SolarEdge Technologies Inc | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page| Open Energy Information Serbia-Enhancing Capacity forSilicium deEnergyCompany LimitedSolar/WindSolarCraftSolarEdge
Sujan Sengupta
1998-01-29
The ohmic decay of magnetic fields confined within the crust of neutron stars is considered by incorporating both the effect of neutron star cooling and the effect of space-time curvature produced by the intense gravitational field of the star. For this purpose a stationary and static gravitational field has been considered with the standard as well as the accelerated cooling models of neutron stars. It is shown that general relativistic effect reduces the magnetic field decay rate substantially. At the late stage of evolution when the field decay is mainly determined by the impurity-electron scattering, the effect of space-time curvature suppresses the role of the impurity content significantly and reduces the decay rate by more than an order of magnitude. Even with a high impurity content the decay rate is too low to be of observational interest if the accelerated cooling model along with the effect of space-time curvature is taken into account. It is, therefore, pointed out that if a decrease in the magnetic field strength by more than two orders of magnitude from its initial value is detected by observation then the existence of quark in the core of the neutron star would possibly be ruled out.
Lotze, Heike K.
mini farmers market where several family vendors, All Sauced Up, Creative Artistry, Tucan Olive Oil or stuffed animal for some medical attention and enjoy the busy crafts table. Learn about how to keep your pets safe. Plant Oil for Fish Food? This interactive exhibit explores using camelina in fish diets
Spinning particles in vacuum space-times of different curvature types -- I
O. Semerįk; M. rįmek
2015-05-05
We consider the motion of spinning test particles with non-zero rest mass in the "pole-dipole" approximation, as described by the Mathisson--Papapetrou--Dixon (MPD) equations, and examine its properties in dependence on the spin supplementary condition added to close the system and on algebraic type of curvature. The MPD equation of motion is first decomposed in the orthonormal tetrad whose time-like vector is given by the four-velocity $V^\\mu$ fixing the spin condition (the "reference observer") and the first spatial vector by the corresponding spin $s^\\mu$; such MPD-equation projections do not contain the Weyl scalars $\\Psi_0$ and $\\Psi_4$ obtained in the related Newman--Penrose null tetrad. One natural option how to choose the remaining two spatial basis vectors, is shown to follow "intrinsically" whenever the reference observer $V^\\mu$ has been chosen; it is realizable if the particle's four-velocity and four-momentum are not parallel. In order to discuss the problem in dependence on space-time Petrov type, it is natural to align the real vectors of the Newman--Penrose tetrad with the Weyl-tensor principal null directions (and thus to set $V^\\mu$ and $s^\\mu$ accordingly). In space-times of any algebraic type but III, it is moreover possible to rotate the tetrad so as to become "transverse", namely so that $\\Psi_1$ and $\\Psi_3$ vanish; the spinning-particle motion is then fully determined by $\\Psi_2$ and the cosmological constant. Besides focusing on specific Petrov types, we derive several sets of useful relations valid generally and check whether/how the exercise simplifies for some particular types of motion. The option of having four-velocity parallel to four-momentum is treated in some detail and a natural resolution of non-uniqueness of the corresponding reference observer $V^\\mu$ is suggested.
Using the Comoving Maximum of the Galaxy Power Spectrum to Measure Cosmological Curvature
Tom Broadhurst; Andrew H. Jaffe
1999-04-26
The large-scale maximum at k~0.05 identified in the power-spectrum of galaxy fluctuations provides a co-moving scale for measuring cosmological curvature. In shallow 3D surveys the peak is broad, but appears to be well resolved in 1D, at ~130 Mpc (k=0.048), comprising evenly spaced peaks and troughs. Surprisingly similar behaviour is evident at z=3 in the distribution of Lyman-break galaxies, for which we find a 5 sigma excess of pairs separated by Delta z=0.22pm0.02, equivalent to 85Mpc for Omega=1, increasing to 170 Mpc for Omega=0, with a number density contrast of 30% averaged over 5 independent fields. The combination, 3.2\\Omega_m -\\Omega_{\\Lambda}=0.7, matches the local scale of 130 Mpc, i.e. Omega=0.2\\pm0.1 or Omega_{m}=0.4\\pm0.1 for the matter-dominated and flat models respectively, with an uncertainty given by the width of the excess correlation. The consistency here of the flat model with SNIa based claims is encouraging, but overshadowed by the high degree of coherence observed in 1D compared with conventional Gaussian models of structure formation. The appearance of this scale at high redshift and its local prominence in the distribution of Abell clusters lends support to claims that the high-z `spikes' represent young clusters. Finally we show that a spike in the primordial power spectrum of delta\\rho/\\rho=0.3 at k=0.05 has little effect on the CMB, except to exaggerate the first Doppler peak in flat matter-dominated models, consistent with recent observations. \\\\effect on the CMB, except to exaggerate the first Doppler peak in flat matter-dominated models, consistent with recent observations.
Reconstruction of the primordial power spectrum of curvature perturbations using multiple data sets
Hunt, Paul; Sarkar, Subir E-mail: s.sarkar@physics.ox.ac.uk
2014-01-01
Detailed knowledge of the primordial power spectrum of curvature perturbations is essential both in order to elucidate the physical mechanism ('inflation') which generated it, and for estimating the cosmological parameters from observations of the cosmic microwave background and large-scale structure. Hence it ought to be extracted from such data in a model-independent manner, however this is difficult because relevant cosmological observables are given by a convolution of the primordial perturbations with some smoothing kernel which depends on both the assumed world model and the matter content of the universe. Moreover the deconvolution problem is ill-conditioned so a regularisation scheme must be employed to control error propagation. We demonstrate that 'Tikhonov regularisation' can robustly reconstruct the primordial spectrum from multiple cosmological data sets, a significant advantage being that both its uncertainty and resolution are then quantified. Using Monte Carlo simulations we investigate several regularisation parameter selection methods and find that generalised cross-validation and Mallow's C{sub p} method give optimal results. We apply our inversion procedure to data from the Wilkinson Microwave Anisotropy Probe, other ground-based small angular scale CMB experiments, and the Sloan Digital Sky Survey. The reconstructed spectrum (assuming the standard ?CDM cosmology) is not scale-free but has an infrared cutoff at k?<5 × 10{sup ?4} Mpc{sup ?1} (due to the anomalously low CMB quadrupole) and several features with ? 2? significance at k/Mpc{sup ?1} ? 0.00130.0025, 0.03620.0402 and 0.0510.056, reflecting the 'WMAP glitches'. To test whether these are indeed real will require more accurate data, such as from the Planck satellite and new ground-based experiments.
ALTERNATIVE MATERIALS FOR RAMP-EDGE SNS JUNCTIONS
Jia, Q.; Fan, Y.
1999-06-01
We report on the processing optimization and fabrication of ramp-edge high-temperature superconducting junctions by using alternative materials for both superconductor electrodes and normal-metal barrier. By using Ag-doped YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} (Ag:YBCO) as electrodes and a cation-modified compound of (Pr{sub y}Gd{sub 0.6{minus}y})Ca{sub 0.4}Ba{sub 1.6}La{sub 0.4}Cu{sub 3}O{sub 7} (y = 0.4, 0.5, and 0.6) as a normal-metal barrier, high-temperature superconducting Josephson junctions have been fabricated in a ramp-edge superconductor/normal-metal/superconductor (SNS) configuration. By using Ag:YBCO as electrodes, we have found that the processing controllability /reproducibility and the stability of the SNS junctions are improved substantially. The junctions fabricated with these alternative materials show well-defined RSJ-like current vs voltage characteristics at liquid nitrogen temperature.
Edge states for the Kalmeyer-Laughlin wave function
Benedikt Herwerth; Germįn Sierra; Hong-Hao Tu; J. Ignacio Cirac; Anne E. B. Nielsen
2015-09-07
We study lattice wave functions obtained from the SU(2)$_1$ Wess-Zumino-Witten conformal field theory. Following Moore and Read's construction, the Kalmeyer-Laughlin fractional quantum Hall state is defined as a correlation function of primary fields. By an additional insertion of Kac-Moody currents, we associate a wave function to each state of the conformal field theory. These wave functions span the complete Hilbert space of the lattice system. On the cylinder, we study global properties of the lattice states analytically and correlation functions numerically using a quantum Monte Carlo method. By comparing short-range bulk correlations, numerical evidence is provided that the states with one current operator represent edge states in the thermodynamical limit. We show that the edge states with one Kac-Moody current of lowest order have a good overlap with low-energy excited states of a local Hamiltonian, for which the Kalmeyer-Laughlin state approximates the ground state. For some states, exact parent Hamiltonians are derived on the cylinder. These Hamiltonians are SU(2) invariant and nonlocal with up to four-body interactions.
Freezing of parallel hard cubes with rounded edges
Matthieu Marechal; Urs Zimmermann; Hartmut Löwen
2012-02-09
The freezing transition in a classical three-dimensional system of parallel hard cubes with rounded edges is studied by computer simulation and fundamental-measure density functional theory. By switching the rounding parameter s from zero to one, one can smoothly interpolate between cubes with sharp edges and hard spheres. The equilibrium phase diagram of rounded parallel hard cubes is computed as a function of their volume fraction and the rounding parameter s. The second order freezing transition known for oriented cubes at s = 0 is found to be persistent up to s = 0.65. The fluid freezes into a simple-cubic crystal which exhibits a large vacancy concentration. Upon a further increase of s, the continuous freezing is replaced by a first-order transition into either a sheared simple cubic lattice or a deformed face-centered cubic lattice with two possible unit cells: body-centered orthorhombic or base-centered monoclinic. In principle, a system of parallel cubes could be realized in experiments on colloids using advanced synthesis techniques and a combination of external fields.
Framework Application for Core Edge Transport Simulation (FACETS)
Krasheninnikov, Sergei; Pigarov, Alexander
2011-10-15
The FACETS (Framework Application for Core-Edge Transport Simulations) project of Scientific Discovery through Advanced Computing (SciDAC) Program was aimed at providing a high-fidelity whole-tokamak modeling for the U.S. magnetic fusion energy program and ITER through coupling separate components for each of the core region, edge region, and wall, with realistic plasma particles and power sources and turbulent transport simulation. The project also aimed at developing advanced numerical algorithms, efficient implicit coupling methods, and software tools utilizing the leadership class computing facilities under Advanced Scientific Computing Research (ASCR). The FACETS project was conducted by a multi-discipline, multi-institutional teams, the Lead PI was J.R. Cary (Tech-X Corp.). In the FACETS project, the Applied Plasma Theory Group at the MAE Department of UCSD developed the Wall and Plasma-Surface Interaction (WALLPSI) module, performed its validation against experimental data, and integrated it into the developed framework. WALLPSI is a one-dimensional, coarse grained, reaction/advection/diffusion code applied to each material boundary cell in the common modeling domain for a tokamak. It incorporates an advanced model for plasma particle transport and retention in the solid matter of plasma facing components, simulation of plasma heat power load handling, calculation of erosion/deposition, and simulation of synergistic effects in strong plasma-wall coupling.
Nakamura, Masanori [Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Garofalo, David; Meier, David L., E-mail: nakamura@stsci.ed, E-mail: david.a.garofalo@jpl.nasa.go, E-mail: david.l.meier@jpl.nasa.go [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
2010-10-01
This is the first in a series of papers that introduces a new paradigm for understanding the jet in M87: a collimated relativistic flow in which strong magnetic fields play a dominant dynamical role. Here, we focus on the flow downstream of HST-1-an essentially stationary flaring feature that ejects trails of superluminal components. We propose that these components are quad relativistic magnetohydrodynamic shock fronts (forward/reverse fast and slow modes) in a narrow jet with a helically twisted magnetic structure. And we demonstrate the properties of such shocks with simple one-dimensional numerical simulations. Quasi-periodic ejections of similar component trails may be responsible for the M87 jet substructures observed further downstream on 10{sup 2}-10{sup 3} pc scales. This new paradigm requires the assimilation of some new concepts into the astrophysical jet community, particularly the behavior of slow/fast-mode waves/shocks and of current-driven helical kink instabilities. However, the prospects of these ideas applying to a large number of other jet systems may make this worth the effort.
Liang, Weifa
THE MOST VITAL EDGE FOR GRAPH MINIMIZATION PROBLEMS ON MESHES AND HYPERCUBES Weifa Liang, Xiaojun Shen be a minimization problem in G. Edge e E is called the most vital edge if its removal from G maximizes the value of P in G(V, E - {e}, w). This paper considers the most vital edge with respect to the minimum spanning
Effect of Deuterium Gas Puff On The Edge Plasma In NSTX
Zweben, S. J.
2014-02-20
This paper describes a detailed examination of the effects of a relatively small pulsed deuterium gas puff on the edge plasma and edge turbulence in NSTX. This gas puff caused little or no change in the line-averaged plasma density or total stored energy, or in the edge density and electron temperature up to the time of the peak of the gas puff. The radial profile of the D? light emission and the edge turbulence within this gas puff did not vary significantly over its rise and fall, implying that these gas puffs did not significantly perturb the local edge plasma or edge turbulence. These measurements are compared with modeling by DEGAS 2, UEDGE, and with simplified estimates for the expected effects of this gas puff.
Simultaneous laser cutting and welding of metal foil to edge of a plate
Pernicka, John C. (Fort Collins, CO); Benson, David K. (Golden, CO); Tracy, C. Edwin (Golden, CO)
1996-01-01
A method of welding an ultra-thin foil to the edge of a thicker sheet to form a vacuum insulation panel comprising the steps of providing an ultra-thin foil having a thickness less than 0.002, providing a top plate having an edge and a bottom plate having an edge, clamping the foil to the edge of the plate wherein the clamps act as heat sinks to distribute heat through the foil, providing a laser, moving the laser relative to the foil and the plate edges to form overlapping weld beads to weld the foil to the plate edges while simultaneously cutting the foil along the weld line formed by the overlapping beads.
Simultaneous laser cutting and welding of metal foil to edge of a plate
Pernicka, J.C.; Benson, D.K.; Tracy, C.E.
1996-03-19
A method is described for welding an ultra-thin foil to the edge of a thicker sheet to form a vacuum insulation panel comprising the steps of providing an ultra-thin foil having a thickness less than 0.002, providing a top plate having an edge and a bottom plate having an edge, clamping the foil to the edge of the plate wherein the clamps act as heat sinks to distribute heat through the foil, providing a laser, moving the laser relative to the foil and the plate edges to form overlapping weld beads to weld the foil to the plate edges while simultaneously cutting the foil along the weld line formed by the overlapping beads. 7 figs.
Zhang, Huizhen; Yang, Haifang; Li, Lin; Fu, Huixia; Ma, Wei; Niu, Chunyao; Sun, Jiatao; Meng, Sheng; Gu, Changzhi
2015-03-21
The electronic properties and relative stability of zigzag graphene nanoribbons are studied by varying the percentage of hydroxyl radicals for edge saturation using first principle calculations. The passivated structures of zigzag graphene nanoribbon have spin-polarized ground state with antiferromagnetic exchange coupling across the edge and ferromagnetic coupling along the edges. When the edges are specially passivated by hydroxyl, the potentials of spin exchange interaction across the two edges shift accordingly, resulting into a spin-semiconductor. Varying the concentration of hydroxyl groups can alter the maximum magnetization splitting. When the percentage of asymmetrically adsorbed hydroxyl reaches 50%, the magnetization splitting can reach a value as high as 275?meV due to the asymmetrical potential across the nanoribbon edges. These results would favor spintronic device applications based on zigzag graphene nanoribbons.
Center for Plasma Edge Simulation (CPES): Final Technical Report
Cummings, Julian C.
2013-02-19
The Center for Plasma Edge Simulation (CPES) project was a multi-institutional research effort funded jointly by the Office of Advanced Scientific Computing Research (OASCR) and the Office of Fusion Energy Sciences (OFES) within the Department of EnergyĆ?Ā¢Ć?Ā?Ć?Ā?s Office of Science. The effort was led by our Principal Investigator, CS Chang, at the Courant Institute for Mathematical Sciences at New York University. The Center included participants from Oak Ridge National Laboratory, Princeton Plasma Physics Laboratory, Lawrence Berkeley National Laboratory, California Institute of Technology, Columbia University, Lehigh University, Rutgers University, University of Colorado, Massachusetts Institute of Technology, University of California at Davis, University of California at Irvine, North Carolina State University, and Georgia Institute of Technology. This report concerns the work performed by Dr. Julian C. Cummings, who was the institutional Principal Investigator for the CPES project at Caltech.
Electrically pumped edge-emitting photonic bandgap semiconductor laser
Lin, Shawn-Yu; Zubrzycki, Walter J.
2004-01-06
A highly efficient, electrically pumped edge-emitting semiconductor laser based on a one- or two-dimensional photonic bandgap (PBG) structure is described. The laser optical cavity is formed using a pair of PBG mirrors operating in the photonic band gap regime. Transverse confinement is achieved by surrounding an active semiconductor layer of high refractive index with lower-index cladding layers. The cladding layers can be electrically insulating in the passive PBG mirror and waveguide regions with a small conducting aperture for efficient channeling of the injection pump current into the active region. The active layer can comprise a quantum well structure. The quantum well structure can be relaxed in the passive regions to provide efficient extraction of laser light from the active region.
Magnetic edge states in Aharonov-Bohm graphene quantum rings
Farghadan, R., E-mail: rfarghadan@kashanu.ac.ir; Heidari Semiromi, E. [Department of Physics, University of Kashan, Kashan (Iran, Islamic Republic of); Saffarzadeh, A. [Department of Physics, Payame Noor University, P.O. Box 19395-3697 Tehran (Iran, Islamic Republic of); Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada)
2013-12-07
The effect of electron-electron interaction on the electronic structure of Aharonov-Bohm (AB) graphene quantum rings (GQRs) is explored theoretically using the single-band tight-binding Hamiltonian and the mean-field Hubbard model. The electronic states and magnetic properties of hexagonal, triangular, and circular GQRs with different sizes and zigzag edge terminations are studied. The results show that, although the AB oscillations in the all types of nanoring are affected by the interaction, the spin splitting in the AB oscillations strongly depends on the geometry and the size of graphene nanorings. We found that the total spin of hexagonal and circular rings is zero and therefore, no spin splitting can be observed in the AB oscillations. However, the non-zero magnetization of the triangular rings breaks the degeneracy between spin-up and spin-down electrons, which produces spin-polarized AB oscillations.
Conductance matrix of multiterminal semiconductor devices with edge channels
Danilovskii, E. Yu. Bagraev, N. T.
2014-12-15
A method for determining the conductance matrix of multiterminal semiconductor structures with edge channels is proposed. The method is based on the solution of a system of linear algebraic equations based on Kirchhoff equations, made up of potential differences U{sub ij} measured at stabilized currents I{sub kl}, where i, j, k, l are terminal numbers. The matrix obtained by solving the system of equations completely describes the structure under study, reflecting its configuration and homogeneity. This method can find wide application when using the known Landauer-Buttiker formalism to analyze carrier transport in the quantum Hall effect and quantum spin Hall effect modes. Within the proposed method, the contribution of the contact area resistances R{sub c} to the formation of conductance matrix elements is taken into account. The possibilities of practical application of the results obtained in developing analog cryptographic devices are considered.
Geometric entropy and edge modes of the electromagnetic field
William Donnelly; Aron C. Wall
2015-06-18
We calculate the vacuum entanglement entropy of Maxwell theory in a class of curved spacetimes by Kaluza-Klein reduction of the theory onto a two-dimensional base manifold. Using two-dimensional duality, we express the geometric entropy of the electromagnetic field as the entropy of a tower of scalar fields, constant electric and magnetic fluxes, and a contact term, whose leading order divergence was discovered by Kabat. The complete contact term takes the form of one negative scalar degree of freedom confined to the entangling surface. We show that the geometric entropy agrees with a statistical definition of entanglement entropy that includes edge modes: classical solutions determined by their boundary values on the entangling surface. This resolves a longstanding puzzle about the statistical interpretation of the contact term in the entanglement entropy. We discuss the implications of this negative term for black hole thermodynamics and the renormalization of Newton's constant.
Gain media edge treatment to suppress amplified spontaneous emission in a high power laser
Hackel, Lloyd A. (Livermore, CA); Soules, Thomas F. (Livermore, CA); Fochs, Scott N. (Livermore, CA); Rotter, Mark D. (San Ramon, CA); Letts, Stephan A. (San Ramon, CA)
2011-02-22
A novel method and apparatus for suppressing ASE and/or parasitic oscillation modes in a laser is introduced. By roughening one or more peripheral edges of a solid-state crystal or ceramic laser gain media and by bonding such edges to a predetermined electromagnetic absorbing material arranged adjacent to the entire outer surface of the peripheral edges of the roughened laser gain media, ASE, parasitic oscillation modes and/or residual pump energy can be effectively suppressed.
Gain media edge treatment to suppress amplified spontaneous emission in a high power laser
Hackel, Lloyd A. (Livermore, CA); Soules, Thomas F. (Livermore, CA); Fochs, Scott N. (Livermore, CA); Rotter, Mark D. (San Ramon, CA); Letts, Stephan A. (San Ramon, CA)
2008-12-09
A novel method and apparatus for suppressing ASE and parasitic oscillation modes in a high average power laser is introduced. By roughening one or more peripheral edges of a solid-state crystal or ceramic laser gain media and by bonding such edges using a substantially high index bonding elastomer or epoxy to a predetermined electromagnetic absorbing arranged adjacent to the entire outer surface of the peripheral edges of the roughened laser gain media, ASE and parasitic oscillation modes can be effectively suppressed.
Boedo, J. A. Rudakov, D. L.; Myra, J. R.; D'Ippolito, D. A.; Zweben, S.; Maingi, R.; Maqueda, R. J.; Bell, R.; Kugel, H.; Leblanc, B.; Roquemore, L. A.; Soukhanovskii, V. A.; Ahn, J. W.; Canik, J.; Crocker, N.
2014-04-15
Transport and turbulence profiles were directly evaluated using probes for the first time in the edge and scrape-off layer (SOL) of NSTX [Ono et al., Nucl. Fusion 40, 557 (2000)] in low (L) and high (H) confinement, low power (P{sub in}? 1.3?MW), beam-heated, lower single-null discharges. Radial turbulent particle fluxes peak near the last closed flux surface (LCFS) at ?4×10{sup 21}?s{sup ?1} in L-mode and are suppressed to ?0.2×10{sup 21}?s{sup ?1} in H mode (80%90% lower) mostly due to a reduction in density fluctuation amplitude and of the phase between density and radial velocity fluctuations. The radial particle fluxes are consistent with particle inventory based on SOLPS fluid modeling. A strong intermittent component is identified. Hot, dense plasma filaments 410?cm in diameter, appear first ?2?cm inside the LCFS at a rate of ?1×10{sup 21}?s{sup ?1} and leave that region with radial speeds of ?35?km/s, decaying as they travel through the SOL, while voids travel inward toward the core. Profiles of normalized fluctuations feature levels of 10% inside LCFS to ?150% at the LCFS and SOL. Once properly normalized, the intermittency in NSTX falls in similar electrostatic instability regimes as seen in other devices. The L-H transition causes a drop in the intermittent filaments velocity, amplitude and number in the SOL, resulting in reduced outward transport away from the edge and a less dense SOL.
Thomas Laetsch
2013-05-17
This paper gives a rigorous interpretation of a Feynman path integral on a Riemannian manifold M with non-positive sectional curvature. A $L^2$ Riemannian metric $G_P$ is given on the space of piecewise geodesic paths $H_P(M)$ adapted to the partition $P$ of $[0,1]$, whence a finite-dimensional approximation of Wiener measure is developed. It is proved that, as $mesh(P) \\to 0$, the approximate Wiener measure converges in a $L^1$ sense to the measure $e^{-\\frac{2 + \\sqrt{3}}{20\\sqrt{3}} \\int_0^1 Scal(\\sigma(s)) ds} d\
Tew, M. W.; Miller, J. T.; van Bokhoven, J. A.
2009-08-01
The particle size effect on the formation of palladium hydride and on surface hydrogen adsorption was studied at room temperature using in situ X-ray absorption spectroscopy at the Pd K and L{sub 3} edges. Hydride formation was indirectly observed by lattice expansion in Pd K edge XANES spectra and by EXAFS analysis. Hydride formation was directly detected in the L{sub 3} edge spectra. A characteristic spectral feature caused by the formation of a Pd-H antibonding state showed strong particle size dependence. The L{sub 3} edge spectra were reproduced using full multiple scattering analysis and density of state calculations, and the contributions of bulk absorbed and surface hydrogen to the XANES spectra could be distinguished. The ratio of hydrogen on the surface versus that in the bulk increased with decreasing particle size, and smaller particles dissolved less hydrogen.
Designing soft-edge flip-flop-based linear pipelines operating in multiple supply voltage regimes$
Pedram, Massoud
Designing soft-edge flip-flop-based linear pipelines operating in multiple supply voltage regimes-flop Pipelined circuits design Near-threshold computing Process variation a b s t r a c t Soft-edge flip-flop (SEFF) based pipelines can improve the performance and energy efficiency of circuits operating
Regularized Laplacian Zero Crossings as Optimal Edge Integrators R. KIMMEL A.M. BRUCKSTEIN
Kimmel, Ron
as suggested by Marr and Hildreth, inherently provides optimal edgeintegration with regard to a very natural] = (rI) exceeds some threshold value. The more advanced edge detectors such as those pro posed by Marr and Hildreth [8] attempt to locate points or curves defined by local maxima of the image gradient. The Marr
Joint spatio-spectral based edge detection for multispectral infrared imagery.
Krishna, Sanjay; Hayat, Majeed M.; Bender, Steven C.; Sharma, Yagya D.; Jang, Woo-Yong; Paskalva, Biliana S.
2010-06-01
Image segmentation is one of the most important and difficult tasks in digital image processing. It represents a key stage of automated image analysis and interpretation. Segmentation algorithms for gray-scale images utilize basic properties of intensity values such as discontinuity and similarity. However, it is possible to enhance edge-detection capability by means of using spectral information provided by multispectral (MS) or hyperspectral (HS) imagery. In this paper we consider image segmentation algorithms for multispectral images with particular emphasis on detection of multi-color or multispectral edges. More specifically, we report on an algorithm for joint spatio-spectral (JSS) edge detection. By joint we mean simultaneous utilization of spatial and spectral characteristics of a given MS or HS image. The JSS-based edge-detection approach, termed Spectral Ratio Contrast (SRC) edge-detection algorithm, utilizes the novel concept of matching edge signatures. The edge signature represents a combination of spectral ratios calculated using bands that enhance the spectral contrast between the two materials. In conjunction with a spatial mask, the edge signature give rise to a multispectral operator that can be viewed as a three-dimensional extension of the mask. In the extended mask, the third (spectral) dimension of each hyper-pixel can be chosen independently. The SRC is verified using MS and HS imagery from a quantum-dot in a well infrared (IR) focal plane array, and the Airborne Hyperspectral Imager.
Fast 2-D Camera Control, Data Acquisition, and Database Techniques for Edge Studies on NSTX
Princeton Plasma Physics Laboratory
Fast 2-D Camera Control, Data Acquisition, and Database Techniques for Edge Studies on NSTX NSTX;NSTX-U 9th IAEA TM Fast 2-D Camera Plasma Edge Studies (W. Davis) May 6-10, 2013 Abstract 2 Fast 2-D. This paper describes image analysis, database techniques, and visualization methods used to organize the fast
The Zak phase and the existence of edge states in graphene
P. Delplace; D. Ullmo; G. Montambaux
2011-09-21
We develop a method to predict the existence of edge states in graphene ribbons for a large class of boundaries. This approach is based on the bulk-edge correspondence between the quantized value of the Zak phase Z(k), which is a Berry phase across an appropriately chosen one-dimensional Brillouin zone, and the existence of a localized state of momentum k at the boundary of the ribbon. This bulk-edge correspondence is rigorously demonstrated for a one dimensional toy model as well as for graphene ribbons with zigzag edges. The range of k for which edge states exist in a graphene ribbon is then calculated for arbitrary orientations of the edges. Finally, we show that the introduction of an anisotropy leads to a topological transition in terms of the Zak phase, which modifies the localization properties at the edges. Our approach gives a new geometrical understanding of edge states, it con?firms and generalizes the results of several previous works.
Light Edges in Degree-Constrained Graphs Prosenjit Bose Michiel Smid David R. Wood
Wismath, Stephen
Light Edges in Degree-Constrained Graphs #3; Prosenjit Bose Michiel Smid David R. Wood School of a graph with bounded degree end-points is said to be light. The primary result of this paper is that ev- ery degree-constrained graph has a light edge, where the degree bound depends on the minimum and aver
Decay to equilibrium of the filament end density along the leading edge of the lamellipodium
Schmeiser, Christian
Decay to equilibrium of the filament end density along the leading edge of the lamellipodium for the dynamics of actin filament ends along the leading edge of the lamellipodium is analyzed. It contains-dimensional meshwork of protein filaments, created by polymerization of actin [6]. In steadily protruding lamellipodia
Modeling of hard part machining: effect of insert edge preparation in CBN cutting tools
Ozel, Tugrul
of advanced cutting tool materials such coated carbides and polycrystalline cubic boron nitrite (CBN). CBNModeling of hard part machining: effect of insert edge preparation in CBN cutting tools Tugrul O the influence of edge preparation in cubic boron nitrite (CBN) cutting tools on process parameters and tool
Diamond, Richard
Over the Energy Edge: Results from a Seven Year New Commercial Buildings Research and Demonstration is that the actual, installed energy-efficiency measures and building characteristics changed from the design practice rather than assumptions based on the regional building code. For example, the Energy Edge small
Matched interface and boundary (MIB) method for elliptic problems with sharp-edged interfaces
Zhou, Yongcheng
Matched interface and boundary (MIB) method for elliptic problems with sharp-edged interfaces with sharp-edged interfaces, thin-layered interfaces and interfaces that intersect with geometric boundary. This work generalizes the matched interface and boundary (MIB) method previously designed for solving
Chevron beam dump for ITER edge Thomson scattering system
Yatsuka, E.; Hatae, T.; Bassan, M.; Itami, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan)] [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Vayakis, G. [ITER Organization, 13115 St Paul Lez Durance Cedex (France)] [ITER Organization, 13115 St Paul Lez Durance Cedex (France)
2013-10-15
This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.
Cutting-edge issues of core-collapse supernova theory
Kotake, Kei [Department of Applied Physics, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180 (Japan); Nakamura, Ko [Faculty of Science and Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo, 169-8555 (Japan); Kuroda, Takami [Department Physik, Universität Basel, Klingelbergstrasse 82, 4056 Basel (Switzerland); Takiwaki, Tomoya [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588 (Japan)
2014-05-02
Based on multi-dimensional neutrino-radiation hydrodynamic simulations, we report several cutting-edge issues about the long-veiled explosion mechanism of core-collapse supernovae (CCSNe). In this contribution, we pay particular attention to whether three-dimensional (3D) hydrodynamics and/or general relativity (GR) would or would not help the onset of explosions. By performing 3D simulations with spectral neutrino transport, we show that it is more difficult to obtain an explosion in 3D than in 2D. In addition, our results from the first generation of full general relativistic 3D simulations including approximate neutrino transport indicate that GR can foster the onset of neutrino-driven explosions. Based on our recent parametric studies using a light-bulb scheme, we discuss impacts of nuclear energy deposition behind the supernova shock and stellar rotation on the neutrino-driven mechanism, both of which have yet to be included in the self-consistent 3D supernova models. Finally we give an outlook with a summary of the most urgent tasks to extract the information about the explosion mechanisms from multi-messenger CCSN observables.
Low Thermal Conductance Transition Edge Sensor (TES) for SPICA
Khosropanah, P.; Dirks, B.; Kuur, J. van der; Ridder, M.; Bruijn, M.; Popescu, M.; Hoevers, H. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrech (Netherlands); Gao, J. R. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrech (Netherlands); Kavil Institute of NanoScience, Faculty of Applied Sciences, Delft University of Technology, Delft (Netherlands); Morozov, D.; Mauskopf, P. [School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff, CF24 3AA (United Kingdom)
2009-12-16
We fabricated and characterized low thermal conductance transition edge sensors (TES) for SAFARI instrument on SPICA. The device is based on a superconducting Ti/Au bilayer deposited on suspended SiN membrane. The critical temperature of the device is 113 mK. The low thermal conductance is realized by using long and narrow SiN supporting legs. All measurements were performed having the device in a light-tight box, which to a great extent eliminates the loading of the background radiation. We measured the current-voltage (IV) characteristics of the device in different bath temperatures and determine the thermal conductance (G) to be equal to 320 fW/K. This value corresponds to a noise equivalent power (NEP) of 3x10{sup -19} W/{radical}(Hz). The current noise and complex impedance is also measured at different bias points at 55 mK bath temperature. The measured electrical (dark) NEP is 1x10{sup -18} W/{radical}(Hz), which is about a factor of 3 higher than what we expect from the thermal conductance that comes out of the IV curves. Despite using a light-tight box, the photon noise might still be the source of this excess noise. We also measured the complex impedance of the same device at several bias points. Fitting a simple first order thermal-electrical model to the measured data, we find an effective time constant of about 2.7 ms and a thermal capacity of 13 fJ/K in the middle of the transition.
Spence, Rodney Brian
1995-01-01
Experiments are conducted to study the effects of channel geometry and asymmetric heating on the heat transfer and friction characteristics of turbulent flows in leading edge cooling channels in stator blades of gas turbines. The leading edge...
Zhao, Weiwei
The quantum anomalous Hall (QAH) effect is predicted to possess, at a zero magnetic field, chiral edge channels that conduct a spin polarized current without dissipation. While edge channels have been observed in previous ...
Sun, P.; Schofield, A. J
2012-01-01
Vision Research, 36, 23512367. Marr, D. (1982). Vision: Asuch as shadows and highlights (Marr, 1982). Edges caused byRusinkiewicz, 2004; Malik, 1987; Marr, 1982). Edges due to
McDermott, Rachael Marie
2009-01-01
It is commonly accepted that ExB velocity shear is responsible for the suppression of edge turbulence, which reduces the losses of both energy and particles across magnetic field lines and results in the formation of edge ...
The Generation of Edge Toroidal Momentum due to Ion Orbit Losses and its Effect on the Scrape-Off Layer
Shimada, Hiroyuki; Fukao, Taishi; Minami, Hirotake; Ukai, Masatoshi; Fujii, Kentaro; Yokoya, Akinari; Fukuda, Yoshihiro; Saitoh, Yuji
2014-08-07
The N K-edge X-ray absorption near edge structure (XANES) spectra of the purine-containing nucleotide, guanosine 5{sup ?}-monophosphate (GMP), in aqueous solution are measured under various pH conditions. The spectra show characteristic peaks, which originate from resonant excitations of N 1s electrons to ?* orbitals inside the guanine moiety of GMP. The relative intensities of these peaks depend on the pH values of the solution. The pH dependence is explained by the core-level shift of N atoms at specific sites caused by protonation and deprotonation. The experimental spectra are compared with theoretical spectra calculated by using density functional theory for GMP and the other purine-containing nucleotides, adenosine 5{sup ?}-monophosphate, and adenosine 5{sup ?}-triphosphate. The N K-edge XANES spectra for all of these nucleotides are classified by the numbers of N atoms with particular chemical bonding characteristics in the purine moiety.
Competition between spin and charge polarized states in nanographene ribbons with zigzag edges
Atsushi Yamashiro; Yukihiro Shimoi; Kikuo Harigaya; Katsunori Wakabayashi
2003-09-26
Effects of the nearest neighbor Coulomb interaction on nanographene ribbons with zigzag edges are investigated using the extended Hubbard model within the unrestricted Hartree-Fock approximation. The nearest Coulomb interaction stabilizes a novel electronic state with the opposite electric charges separated and localized along both edges, resulting in a finite electric dipole moment pointing from one edge to the other. This charge-polarized state competes with the peculiar spin-polarized state caused by the on-site Coulomb interaction and is stabilized by an external electric field.
Snizhko, K.
In a recent experimental paper [Bid et al., Nature 466, 585 (2010)] a qualitative confirmation of the existence of upstream neutral modes at the ? = 2/3 quantum Hall edge was reported. Using the chiral Luttinger liquid ...
CAES Grants on the Edge Research Proposal Resubmission Grants -Announcement for FY 2016
Arnold, Jonathan
CAES Grants on the Edge Research Proposal Resubmission Grants - Announcement for FY 2016 The CAES The proposals will be reviewed by staff from the CAES Associate Deans' offices and the Office of the Vice
Turbulence and transport phenomena in edge and scrape-off-layer plasmas
Cziegler, Istvįn
2011-01-01
This thesis reports recent experimental studies of edge turbulence structure using gas-puff-imaging at high time resolution in a radially broad zone at the low-field-side of Alcator C-Mod[1], and highlights the connections ...
Building the water edge : a public event for art and artists at Fort Point Channel
Godwin, Audrey
1996-01-01
The thesis deals with building the water edge at Fort Point Channel, between Congress Street and Summer Street Bridges. It serves as a public event that intends to establish continuity of movement along the waterfront. The ...
Investigations of flow and film cooling on turbine blade edge regions
Yang, Huitao
2006-10-30
the stagnation line from the pressure side, to the leading edge and the suction side, while film cooling protection moves in the reverse direction with decreasing cooling effectiveness. Film cooling brings a high unsteady intensity of the heat transfer...
Leading Edge Flow Structure of a Dynamically Pitching NACA 0012 Airfoil
Pruski, Brandon
2012-11-27
oscillations. The formation and complex evolution of the leading edge vortex is observed. This vortex is seen to grow, interact with surrounding vorticity, detach from the surface, and convect downstream. A statistical analysis coupled with instantaneous...
Quality Evaluation of Motion-Compensated Edge Artifacts in Compressed Video
Leontaris, Athanasios; Cosman, Pamela C; Reibman, Amy R
2007-01-01
at block boundaries (off grid). Fractional-pixel MC andand noisier refers to off-grid edge artifacts (MCEA).DC values. Since MC causes off-grid blocking artifacts, most
TCAT to Receive Ithaca's First 'Cutting-Edge' Fuel Cell Bus ...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
TCAT to Receive Ithaca's First 'Cutting-Edge' Fuel Cell Bus September 6th, 2013 By Kerry Close Within two years, TCAT riders may be able to make their commute on a "clean,...
Edge transport barrier studies on the Alcator C-Mod tokamak
Hughes, Jerry W. (Jerry Wayne), 1975-
2005-01-01
Edge transport barriers (ETBs) in tokamak plasmas accompany transitions from low confinement (L-mode) to high confinement (H-mode) and exhibit large density and temperature gradients in a narrow pedestal region near the ...
Electric field control of spin-resolved edge states in graphene quantum nanorings
Farghadan, R.; Saffarzadeh, A.
2014-05-07
The electric-field effect on the electronic and magnetic properties of triangular and hexagonal graphene quantum rings with zigzag edge termination is investigated by means of the single-band tight-binding Hamiltonian and the mean-field Hubbard model. It is shown how the electron and spin states in the nanoring structures can be manipulated by applying an electric field. We find different spin-depolarization behaviors with variation of electric field strength due to the dependence of spin densities on the shapes and edges of this kind of nanorings. In the case of triangular quantum rings, the magnetization on the inner and outer edges can be selectively tuned and the spin states depolarize gradually as the field strength is increased, while in the case of hexagonal nanorings, the transverse electric field reduces the magnetic moments on both inner and outer edges symmetrically and rapidly.
O'Brien, James F.
system to minimize some "cost" or "energy" functional associated with the surface. The resulting smoothComputer-Aided Design & Applications, Vol. 4, Nos. 1-4, 2007, pp xxx-yyy 1 Energy Minimizers@eecs.berkeley.edu CS Division, University of California, Berkeley ABSTRACT We compare curvature-based surface
E. A. Pashitskii; V. I. Pentegov
2015-10-09
We suggest that the "Big Bang" may be a result of the first-order phase transition driven by changing scalar curvature of the 4D space-time in expanding cold Universe, filled with nonlinear scalar field $\\phi $ and neutral matter with equation of state $p=\
Pashitskii, E A
2015-01-01
We suggest that the "Big Bang" may be a result of the first-order phase transition driven by changing scalar curvature of the 4D space-time in expanding cold Universe, filled with nonlinear scalar field $\\phi $ and neutral matter with equation of state $p=\
Dynamics and generation mechanisms of mesoscale structures in tokamak edge plasmas
Krasheninnikov, S. I. [University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093 (United States); Smolyakov, A. I. [University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5E2 (Canada)
2008-05-15
Intermittent convective-like plasma transport associated with mesoscale coherent structures extended along the magnetic field lines (''blobs'') is often dominant at the edge of tokamaks, stellarators, and linear devices. Blobs can travel a large distance toward the wall ({approx}10 cm and larger) and strongly enhance both edge plasma energy and particle transport and plasma-wall interactions. The dynamics of blobs and blob generation mechanisms are discussed in this paper.
Cummings, Julian C.
2013-05-15
This project was a collaboration between researchers at the California Institute of Technology and the University of California, Irvine to investigate the utility of a global field-aligned mesh and gyrokinetic field solver for simulations of the tokamak plasma edge region. Mesh generation software from UC Irvine was tested with specific tokamak edge magnetic geometry scenarios and the quality of the meshes and the solutions to the gyrokinetic Poisson equation were evaluated.
SINTEF Building and Infrastructure; Norwegian University of Science and Technology; Bergh, Sofie Van Den; Hart, Robert; Jelle, Bjrn Petter; Gustavsen, Arild
2013-01-31
Insulating glass (IG) units typically consist of multiple glass panes that are sealed and held together structurally along their perimeters. This report describes a study of edge seals in IG units. First, we summarize the components, requirements, and desired properties of edge construction in IG units, based on a survey of the available literature. Second, we review commercially available window edge seals and describe their properties, to provide an easily accessible reference for research and commercial purposes. Finally, based on the literature survey and review of current commercial edge seal systems, we identify research opportunities for future edge seal improvements and solutions.
Edge effects in graphene nanostructures: I. From multiple reflection expansion to density of states
J. Wurm; K. Richter; I. Adagideli
2011-08-06
We study the influence of different edge types on the electronic density of states of graphene nanostructures. To this end we develop an exact expansion for the single particle Green's function of ballistic graphene structures in terms of multiple reflections from the system boundary, that allows for a natural treatment of edge effects. We first apply this formalism to calculate the average density of states of graphene billiards. While the leading term in the corresponding Weyl expansion is proportional to the billiard area, we find that the contribution that usually scales with the total length of the system boundary differs significantly from what one finds in semiconductor-based, Schr\\"odinger type billiards: The latter term vanishes for armchair and infinite mass edges and is proportional to the zigzag edge length, highlighting the prominent role of zigzag edges in graphene. We then compute analytical expressions for the density of states oscillations and energy levels within a trajectory based semiclassical approach. We derive a Dirac version of Gutzwiller's trace formula for classically chaotic graphene billiards and further obtain semiclassical trace formulae for the density of states oscillations in regular graphene cavities. We find that edge dependent interference of pseudospins in graphene crucially affects the quantum spectrum.
Bootstrap Current for the Edge Pedestal Plasma in a Diverted Tokamak Geometry
Koh, S.; Chang, C. S.; Ku, S.; Menard, J. E.; Weitzner, H.; Choe, W.
2012-08-10
The edge bootstrap current plays a critical role in the equilibrium and stability of the steep edge pedestal plasma. The pedestal plasma has an unconventional and difficult neoclassical property, as compared with the core plasma. It has a narrow passing particle region in velocity space that can be easily modified or destroyed by Coulomb collisions. At the same time, the edge pedestal plasma has steep pressure and electrostatic potential gradients whose scale-lengths are comparable with the ion banana width, and includes a magnetic separatrix surface, across which the topological properties of the magnetic field and particle orbits change abruptly. A driftkinetic particle code XGC0, equipped with a mass-momentum-energy conserving collision operator, is used to study the edge bootstrap current in a realistic diverted magnetic field geometry with a self-consistent radial electric field. When the edge electrons are in the weakly collisional banana regime, surprisingly, the present kinetic simulation confirms that the existing analytic expressions [represented by O. Sauter et al. , Phys. Plasmas 6 , 2834 (1999)] are still valid in this unconventional region, except in a thin radial layer in contact with the magnetic separatrix. The agreement arises from the dominance of the electron contribution to the bootstrap current compared with ion contribution and from a reasonable separation of the trapped-passing dynamics without a strong collisional mixing. However, when the pedestal electrons are in plateau-collisional regime, there is significant deviation of numerical results from the existing analytic formulas, mainly due to large effective collisionality of the passing and the boundary layer trapped particles in edge region. In a conventional aspect ratio tokamak, the edge bootstrap current from kinetic simulation can be significantly less than that from the Sauter formula if the electron collisionality is high. On the other hand, when the aspect ratio is close to unity, the collisional edge bootstrap current can be significantly greater than that from the Sauter formula. Rapid toroidal rotation of the magnetic field lines at the high field side of a tight aspect-ratio tokamak is believed to be the cause of the different behavior. A new analytic fitting formula, as a simple modification to the Sauter formula, is obtained to bring the analytic expression to a better agreement with the edge kinetic simulation results
Superintegrability on N-dimensional spaces of constant curvature from so(N + 1) and its contractions
Herranz, F. J., E-mail: fjherranz@ubu.e [Universidad de Burgos, Departamento de Fisica, Escuela Politecnica Superior (Spain); Ballesteros, A., E-mail: angelb@ubu.e [Universidad de Burgos, Departamento de Fisica, Facultad de Ciencias (Spain)
2008-05-15
The Lie-Poisson algebra so(N + 1) and some of its contractions are used to construct a family of superintegrable Hamiltonians on the N-dimensional spherical, Euclidean, hyperbolic, Minkowskian, and (anti-)de Sitter spaces. We firstly present a Hamiltonian which is a superposition of an arbitrary central potential with N arbitrary centrifugal terms. Such a system is quasi-maximally superintegrable since this is endowed with 2N - 3 functionally independent constants of motion (plus the Hamiltonian). Secondly, we identify two maximally superintegrable Hamiltonians by choosing a specific central potential and finding at the same time the remaining integral. The former is the generalization of the Smorodinsky-Winternitz system to the above six spaces, while the latter is a generalization of the Kepler-Coulomb potential, for which the Laplace-Runge-Lenz N vector is also given. All the systems and constants of motion are explicitly expressed in a unified form in terms of ambient and polar coordinates as they are parametrized by two contraction parameters (curvature and signature of the metric).
On the low carrier lifetime edge zone in multicrystalline silicon ingots
Jiang, Tingting; Yu, Xuegong; Wang, Lei; Gu, Xin; Yang, Deren, E-mail: mseyang@zju.edu.cn [State Key Laboratory of Silicon Materials and Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)
2014-01-07
We have demonstrated the cause of low minority carrier lifetime corresponding to the edge zone of casting multicrystalline silicon ingots and its influence on the performance of solar cells. It is found that the concentration of substitutional carbon, interstitial oxygen, and dislocation density have no direct correlation with the low minority carrier lifetime in the edge zone. However, the distribution of interstitial iron exactly coincides with the minority carrier lifetime, indicating that iron contamination is mainly responsible for the lifetime degradation. After phosphorus diffusion gettering process, the low carrier lifetime region became narrower, and the concentration of interstitial iron is reduced by almost one order of magnitude. However, the carrier lifetime in the edge zone cannot be raised to average level. After celling process, the internal quantum efficiency map of the edge zone has a lower response to the long wavelength light, in accordance with the minority carrier lifetime distribution in this region. Therefore, the solar cells based on edge zones exhibit slightly lower efficiency than those conventional ones.
J. Wurm; K. Richter; I. Adagideli
2011-11-14
We investigate the effect of different edge types on the statistical properties of both the energy spectrum of closed graphene billiards and the conductance of open graphene cavities in the semiclassical limit. To this end, we use the semiclassical Green's function for ballistic graphene flakes that we have derived in Reference 1. First we study the spectral two point correlation function, or more precisely its Fourier transform the spectral form factor, starting from the graphene version of Gutzwiller's trace formula for the oscillating part of the density of states. We calculate the two leading order contributions to the spectral form factor, paying particular attention to the influence of the edge characteristics of the system. Then we consider transport properties of open graphene cavities. We derive generic analytical expressions for the classical conductance, the weak localization correction, the size of the universal conductance fluctuations and the shot noise power of a ballistic graphene cavity. Again we focus on the effects of the edge structure. For both, the conductance and the spectral form factor, we find that edge induced pseudospin interference affects the results significantly. In particular intervalley coupling mediated through scattering from armchair edges is the key mechanism that governs the coherent quantum interference effects in ballistic graphene cavities.
Localization and topology protected quantum coherence at the edge of 'hot' matter
Yasaman Bahri; Ronen Vosk; Ehud Altman; Ashvin Vishwanath
2013-10-04
Topological phases are often characterized by special edge states confined near the boundaries by an energy gap in the bulk. On raising temperature, these edge states are lost in a clean system due to mobile thermal excitations. Recently however, it has been established that disorder can localize an isolated many body system, potentially allowing for a sharply defined topological phase even in a highly excited state. Here we show this to be the case for the topological phase of a one dimensional magnet with quenched disorder, which features spin one-half excitations at the edges. The time evolution of a simple, highly excited, initial state is used to reveal quantum coherent edge spins. In particular, we demonstrate, using theoretical arguments and numerical simulation, the coherent revival of an edge spin over a time scale that grows exponentially bigger with system size. This is in sharp contrast to the general expectation that quantum bits strongly coupled to a 'hot' many body system will rapidly lose coherence.
Gas turbine bucket wall thickness control
Stathopoulos, Dimitrios (Glenmont, NY); Xu, Liming (Greenville, SC); Lewis, Doyle C. (Greer, SC)
2002-01-01
A core for use in casting a turbine bucket including serpentine cooling passages is divided into two pieces including a leading edge core section and a trailing edge core section. Wall thicknesses at the leading edge and the trailing edge of the turbine bucket can be controlled independent of each other by separately positioning the leading edge core section and the trailing edge core section in the casting die. The controlled leading and trailing edge thicknesses can thus be optimized for efficient cooling, resulting in more efficient turbine operation.
Peeling-off of the external kink modes at tokamak plasma edge
Zheng, L J
2014-01-01
It is pointed that there is a current jump between the edge plasma inside the last closed magnetic surface and the scrape-off layer and the current jump can lead the external kink modes to convert to the tearing modes, due to the current interchange effects [L. J. Zheng and M. Furukawa, Phys. Plasmas 17, 052508 (2010)]. The magnetic reconnection in the presence of tearing modes subsequently causes the tokamak edge plasma to be peeled off to link to the diverters. In particular, the peeling or peeling-ballooning modes can become the "peeling-off" modes in this sense. This phenomenon indicates that the tokamak edge confinement can be worse than the expectation based on the conventional kink mode picture.
Observation of phononic helical edge states in a mechanical 'topological insulator'
Süsstrunk, Roman
2015-01-01
A topological insulator is characterized by a dichotomy between the interior and the edge of a finite system: While the bulk has a non-zero energy gap, the edges are forced to sustain excitations traversing these gaps. Originally proposed for electrons governed by quantum mechanics, it has remained an important open question if the same physics can be observed for systems obeying Newton's equations of motion. Here, we report on measurements that characterize the collective behavior of mechanical oscillators exhibiting the phenomenology of the quantum spin hall effect. The phononic edge modes are shown to be helical and we demonstrate their topological protection via the stability against imperfections. Our results open the door to the design of topological acoustic meta-materials that can capitalize on the stability of the surfaces phonons as reliable wave guides.
The effect of spin-orbit coupling in band structure and edge states of bilayer graphene
Sahdan, Muhammad Fauzi; Darma, Yudi
2015-04-16
Topological insulators are predicted to be useful ranging from spintronics to quantum computation. Graphene was first predicted to be the precursor of topological insulator by Kane-Mele. They developed a Hamiltonian model to describe the gap opening in graphene. In this work, we investigate the band structure of bilayer grapheme and also its edge states by using this model with analytical approach. The results of our calculation show that the gap opening occurs at K and K point in bilayer graphene.In addition, a pair of gapless edge modes occurs both in the zigzag and arm-chair configurations are no longer exist. There are gap created at the edge even though thery are very small.
Peeling-off of the external kink modes at tokamak plasma edge
Zheng, L. J. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States); Furukawa, M. [Graduate School of Engineering, Tottori University, Tottori 680-8552 (Japan)
2014-08-15
It is pointed out that there is a current jump between the edge plasma inside the last closed flux surface and the scrape-off layer and that the current jump can lead the external kink modes to convert to the tearing modes, due to the current interchange effects [L. J. Zheng and M. Furukawa, Phys. Plasmas 17, 052508 (2010)]. The magnetic reconnection in the presence of tearing modes subsequently causes the tokamak edge plasma to be peeled off to link to the divertors. In particular, the peeling or peeling-ballooning modes can become the peeling-off modes in this sense. This phenomenon indicates that the tokamak edge confinement can be worse than the expectation based on the conventional kink mode picture.
Visualizing edge states with an atomic Bose gas in the quantum Hall regime
B. K. Stuhl; H. -I Lu; L. M. Aycock; D. Genkina; I. B. Spielman
2015-02-09
We engineered a two-dimensional magnetic lattice in an elongated strip geometry, with effective per-plaquette flux ~4/3 times the flux quanta. We imaged the localized edge and bulk states of atomic Bose-Einstein condensates in this strip, with single lattice-site resolution along the narrow direction. Further, we observed both the skipping orbits of excited atoms traveling down our system's edges, analogues to edge magnetoplasmons in 2-D electron systems, and a dynamical Hall effect for bulk excitations. Our lattice's long direction consisted of the sites of an optical lattice and its narrow direction consisted of the internal atomic spin states. Our technique has minimal heating, a feature that will be important for spectroscopic measurements of the Hofstadter butterfly and realizations of Laughlin's charge pump.
X-ray K-edge analysis of drain lines in Wilhelm Hall, Ames Laboratory
Jensen, T.; Whitmore, C. |
1999-01-05
From August 12--27, 1998 X-ray K-edge measurements were made on drain lines in seven rooms in Wilhelm Hall, Ames Laboratory. The purpose of these measurements was to determine the extent of thorium (and other heavy metal) contamination inside these pipes. The K-edge method is a noninvasive inspection technique that can provide accurate quantification of heavy metal contamination interior to an object. Of the seven drain lines inspected, one was found to have no significant contamination, three showed significant thorium deposits, two showed mercury contamination, and one line was found to contain mercury, thorium and uranium. The K-edge measurements were found to be consistent with readings from hand-held survey meters, and provided much greater detail on the location and amount of heavy metal contamination.
Roman G. Smirnov; Jin Yue
2004-08-03
The invariant theory of Killing tensors (ITKT) is extended by introducing the new concepts of covariants and joint invariants of (product) vector spaces of Killing tensors defined in pseudo-Riemannian spaces of constant curvature. The covariants are employed to solve the problem of classification of the orthogonal coordinate webs generated by non-trivial Killing tensors of valence two defined in the Euclidean and Minkowski planes. Illustrative examples are provided.
Igor Romanovsky; Constantine Yannouleas; Uzi Landman
2012-10-17
Systematic tight-binding investigations of the electronic spectra (as a function of the magnetic field) are presented for trigonal graphene nanoflakes with reconstructed zigzag edges, where a succession of pentagons and heptagons, that is 5-7 defects, replaces the hexagons at the zigzag edge. For nanoflakes with such reczag defective edges, emphasis is placed on topological aspects and connections underlying the patterns dominating these spectra. The electronic spectra of trigonal graphene nanoflakes with reczag edge terminations exhibit certain unique features, in addition to those that are well known to appear for graphene dots with zigzag edge termination. These unique features include breaking of the particle-hole symmetry, and they are associated with nonlinear dispersion of the energy as a function of momentum, which may be interpreted as nonrelativistic behavior. The general topological features shared with the zigzag flakes include the appearance of energy gaps at zero and low magnetic fields due to finite size, the formation of relativistic Landau levels at high magnetic fields, and the presence between the Landau levels of edge states (the socalled Halperin states) associated with the integer quantum Hall effect. Topological regimes, unique to the reczag nanoflakes, appear within a stripe of negative energies E_b < E < 0, and along a separate feature forming a constant-energy line outside this stripe. The lower bound (E_b) specifying the energy stripe is independent of size. A main finding concerns the limited applicability of the continuous Dirac-Weyl equation, since the latter does not reproduce the special reczag features. (See also the extended abstract in the paper.)
Topological edge states in two-gap unitary systems: A transfer matrix approach
Clément Tauber; Pierre Delplace
2015-09-17
We construct and investigate a family of two-band unitary systems living on a cylinder geometry and presenting localized edge states. Using the transfer matrix formalism, we solve and investigate in details such states in the thermodynamic limit. Analitycity considerations then suggest the construction of a family of Riemman surfaces associated to the band structure of the system. In this picture, the corresponding edge states naturally wind around non contractile loops, defining by the way a topological invariant associated to each gap of the system.
Using LGI experiments to achieve better understanding of pedestal-edge coupling in NSTX-U
Wang, Zhehui
2015-02-23
PowerPoint presentation. Latest advances in granule or dust injection technologies, fast and high-resolution imaging, together with micro-/nano-structured material fabrication, provide new opportunities to examine plasma-material interaction (PMI) in magnetic fusion environment. Some of our previous work in these areas is summarized. The upcoming LGI experiments in NSTX-U will shed new light on granular matter transport in the pedestal-edge region. In addition to particle control, these results can also be used for code validation and achieving better understanding of pedestal-edge coupling in fusion plasmas in both NSTX-U and others.
Oxidation of step edges on vicinal 4H-SiC(0001) surfaces
Li, Wenbo; Zhu, Qiaozhi; Wang, Dejun, E-mail: dwang121@dlut.edu.cn [School of Electronic Science and Technology, Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 (China)] [School of Electronic Science and Technology, Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 (China); Zhao, Jijun [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), College of Advanced Science and Technology, Ministry of Education, Dalian 116024 (China)] [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), College of Advanced Science and Technology, Ministry of Education, Dalian 116024 (China)
2013-11-18
The oxidation processes of stepped SiC(0001) surfaces are studied within the ab initio atomistic thermodynamics approach. Our calculations show that a one-dimensional -Si-O- chain structure as a precursor for oxide growth on stepped SiC surfaces is formed along the step edge, promoting further oxidation of the step edges. Following the modified Deal-Grove oxidation model, we also find that the oxidation rate at steps is higher than that at terraces by three orders of magnitude. These findings give a reasonable explanation for the oxide thickness fluctuation between the step and the terrace observed in the previous experiments.
TEMPEST Simulations of Collisionless Damping of Geodesic-Acoustic Mode in Edge Plasma Pedestal
Xu, X Q; Xiong, Z; Nevins, W M; McKee, G R
2007-05-30
The fully nonlinear (full-f) 4D TEMPEST gyrokinetic continuum code produces frequency, collisionless damping of GAM and zonal flow with fully nonlinear Boltzmann electrons for the inverse aspect ratio {epsilon}-scan and the tokamak safety factor q-scan in homogeneous plasmas. The TEMPEST simulation shows that GAM exists in edge plasma pedestal for steep density and temperature gradients, and an initial GAM relaxes to the standard neoclassical residual, rather than Rosenbluth-Hinton residual due to the presence of ion-ion collisions. The enhanced GAM damping explains experimental BES measurements on the edge q scaling of the GAM amplitude.
Topological edge states in two-gap unitary systems: A transfer matrix approach
Clément Tauber; Pierre Delplace
2015-10-23
We construct and investigate a family of two-band unitary systems living on a cylinder geometry and presenting localized edge states. Using the transfer matrix formalism, we solve and investigate in details such states in the thermodynamic limit. Analitycity considerations then suggest the construction of a family of Riemman surfaces associated to the band structure of the system. In this picture, the corresponding edge states naturally wind around non contractile loops, defining by the way a topological invariant associated to each gap of the system.
Estimating Dual-scale Properties of Glossy Surfaces from Step-edge Lighting Chun-Po Wang
Keinan, Alon
-edge illumination from a pla- nar sample of a surface to estimate both the BRDF and the statistics of meso-scale
Ammar H Hakim
2011-10-20
In this Phase I project we have extended the BOUT++ code to solve edge fluid equations. We added a simple neutral fluid model, created a mesh generator as well as collected a set of difficult test problems for benchmarking edge codes. The work in this project should be useful as a starting point to build a complete set of edge fluid equations in BOUT++ that would enhance its ability to not only perform edge turbulence calculations, but also allow the coupled transport-turbulence equations evolved in an efficient manner.
MyRED Registration Audit Trail Registration Audit Trail
Farritor, Shane
ID and indicate the term you wish to view. Click Search. If you don't indicate the term before you click Search, a list of applicable terms to select from will appear below. September 15, 2011 a particular course, enter the Subject Area and/or Catalog Nbr into the Filter and click Search. 1 #12;My
PPPL-3464 PPPL-3464 Visible Imaging of Edge Turbulence in NSTX
in Calendar Year 2000. The home page for PPPL Reports and Publications is: http://www.pppl.gov/pub_report/ DOE have shown that the visible light emission from the plasma edge as measured on a microsecond timescale-10 cm). These light fluctuations are thought to be due to the rapid excitation of the neutral atoms
Plasma Interface Issues and Edge Modeling APEX Interim Report November, 1999
California at Los Angeles, University of
of the entire first-wall, the response of liquid divertor plates for tokamaks (studied under the ALPS project a complete evaluation of the interactions just described involving core plasma, edge plasma and liquid walls First-Wall Evaporation (T.D Rognlien and M.E. Rensink) 12.4 Impurities from High Heat-Load Divertor
Under consideration for publication in J. Fluid Mech. 1 Edges in Models of Shear Flow
Lebovitz, Norman
Under consideration for publication in J. Fluid Mech. 1 Edges in Models of Shear Flow Norman)). The latter problem is ap- proached theoretically by considering first a laminar shear flow (plane Couette of the laminar flow. This places particular importance on understanding the nature of the boundary of the basin
Edge-spin accumulation in semiconductor two-dimensional hole gases RID E-5081-2010
Nomura, K.; Wunderlich, J.; Sinova, Jairo; Kaestner, B.; MacDonald, AH; Jungwirth, T.
2005-01-01
The controlled generation of localized spin densities is a key enabler of semiconductor spintronics In this work, we study spin Hall effect induced edge-spin accumulation in a two-dimensional hole gas with strong spin orbit interactions. We argue...
Learn more: ece.duke.edu Our department is on the cutting edge
Business & management consulting Construction, manufacturing, energy/mining, utilities EngineeringLearn more: ece.duke.edu Our department is on the cutting edge of technology. Duke ECE conducts processing and live art: performance and technology · Redesigning wireless Internet with software radios
Retinal Vessel Extraction Using Multiscale Matched Filters, Confidence and Edge Measures
Bystroff, Chris
Retinal Vessel Extraction Using Multiscale Matched Filters, Confidence and Edge Measures Michal of improving detection of low-contrast and narrow vessels and eliminating false detections at non-vascular structures, a new technique is presented for extracting vessels in retinal images. The core of the technique
Self-similarity of the plasma edge fluctuations B. A. Carreras
van Milligen, Boudewijn
long-range dependence in plasma edge fluctuations Mandelbrot and Wallis, Water Resources Res. 4, 909 1969 . This technology has been applied to data from several confinement devices such as tokamaks, stellarators, and reversed-field pinch. The results reveal the self-similar character of the electrostatic
A FLASH-FLOODING STORM AT THE STEEP EDGE OF HIGH
Houze Jr., Robert A.
A FLASH-FLOODING STORM AT THE STEEP EDGE OF HIGH TERRAIN Disaster in the Himalayas by Kristen L. rasmussen and robert a. Houze Jr. A lethal flash flood inundated a town when moist airflow from the lowlands the catastrophic slow-rise flooding of the Indus River in Pakistan in late July 2010 (Houze et al. 2011), flooding
Edge preserving orientation adaptive filtering P. Bakker, L.J. van Vliet, P.W. Verbeek
van Vliet, Lucas J.
Introduction Noise, which is present in every real world image, hampers manual interpretation by human experts able filters [2]. Edges between domains are important features for the interpretation of images images. The natural images are seismic im ages, which are narrow banded and contain layered structures
Edge preserving orientation adaptive filtering P. Bakker, L.J. van Vliet, P.W. Verbeek
van Vliet, Lucas J.
Introduction Noise, which is present in every real world image, hampers manual interpretation by human experts- able filters [2]. Edges between domains are important features for the interpretation of images images. The natural images are seismic im- ages, which are narrow banded and contain layered structures
Critical gradients and plasma flows in the edge plasma of Alcator C-Mod
LaBombard, B.; Hughes, J. W.; Smick, N.; Marr, K.; McDermott, R.; Reinke, M.; Greenwald, M.; Lipschultz, B.; Terry, J. L.; Whyte, D. G.; Graf, A.; Zweben, S. J.
2008-05-15
Recent experiments have led to a fundamental shift in our view of edge transport physics; transport near the last-closed flux surface may be more appropriately described in terms of a critical gradient phenomenon rather than a diffusive and/or convective paradigm. Edge pressure gradients, normalized by the square of the poloidal magnetic field strength, appear invariant in plasmas with the same normalized collisionality, despite vastly different currents and magnetic fields--a behavior that connects with first-principles electromagnetic plasma turbulence simulations. Near-sonic scrape-off layer (SOL) flows impose a cocurrent rotation boundary condition on the confined plasma when Bx{nabla}B points toward the active x-point, suggesting a link to the concomitant reduction in input power needed to attain high-confinement modes. Indeed, low-confinement mode plasmas are found to attain higher edge pressure gradients in this configuration, independent of the direction of B, evidence that SOL flows may affect transport and 'critical gradient' values in the edge plasma.
Investigation of ELM [edge localized mode] Dynamics with the Resonant Magnetic Perturbation Effects
Pankin, Alexei Y.; Kritz, Arnold H.
2011-07-19
Topics covered are: anomalous transport and E x B flow shear effects in the H-mode pedestal; RMP (resonant magnetic perturbation) effects in NSTX discharges; development of a scaling of H-mode pedestal in tokamak plasmas with type I ELMs (edge localized modes); and divertor heat load studies.
NONAXISYMMETRIC ENDWALL CONTOURING AND LEADING EDGE MODIFICATIONS ON TURBINE NOZZLE GUIDE VANES
Guiltinan, Mark
of the nozzle guide vane (NGV) and the hub endwall. It forms a smooth transition from the NGV leading edge facilities with no rotor influence or isolated annular NGV cascades. The procedure was to evaluate the new having a diameter of 91.66 cm. It has a stationary NGV assembly with 23 vanes and a High Pressure (HP
École Normale Supérieure
Extraction of coherent bursts from turbulent edge plasma in magnetic fusion devices using, as they determine the confinement properties of the overall plasma in the bulk region and the energy density to be handled by the limiter or divertor components in the shadowed region of the plasma, where the magnetic
Fast 2-D camera control, data acquisition, and database techniques for edge studies on NSTX
Princeton Plasma Physics Laboratory
Fast 2-D camera control, data acquisition, and database techniques for edge studies on NSTX W Nova Photonics, Princeton, NJ, 08543, USA Abstract Fast 2-D cameras examine a variety of important methods used to organize the fast camera data and to facilitate physics insights from it. An example
Vertical quantum wire realized with double cleaved-edge overgrowth S. F. Roth,a
Grayson, Matthew
-point measurements. The density on the first facet is modulated by the substrate potential, depleting a 2 m wide-dimensional electron states at the corner. © 2006 American Institute of Physics. DOI: 10.1063/1.2222347 An elegant technique for fabricating clean one- dimensional 1D quantum wires is cleaved-edge overgrowth CEO ,1 where
Edge-Enriched Graphitic Anodes by KOH Activation for Higher Rate Capability Lithium Ion Batteries
Lithium Ion Batteries D. Zakhidov,1,2 R. Sugamata,3 T. Yasue,3 T. Hayashi,3 Y. A. Kim,3 and M. Endo4 1 successful anode for lithium ion batteries due to its low cost, safety, and ease of fabrication, but higher are expected to surpass conventional graphite anodes due to larger number of edges for lithium ion
Seedbed variation from the interior through the edge of a large wildfire in Alberta
Macdonald, Ellen
Seedbed variation from the interior through the edge of a large wildfire in Alberta David F. Greene of a very large (>100 000 ha) 2001 wildfire in the mixedwood boreal region of Alberta, we examined forźt mixte boréale de l'Alberta. De faēon ą minimiser les effets de station et de composition
Evolution of Landau Levels into Edge States in Graphene Guohong Li1
Andrei, Eva Y.
field), as is the case in typical graphene devices then, similar to the case in semiconductor-based 2DES,1 Evolution of Landau Levels into Edge States in Graphene Guohong Li1 , Adina Luican-Mayer1 semiconductor based two-dimensional electron systems these elegant concepts were difficult to realize because
Paris-Sud XI, Université de
1 EX/P4-1 Hydrocarbon Characteristics in Fusion Edge Plasmas from Electron- Molecule and Ion proceeding in the volume before and at the wall. Surface processes involving hydrocarbons and their ions, which are probable vacuum contaminants in plasma devices, and the role of hydrocarbon chemistry
EdgeMiner: Automatically Detecting Implicit Control Flow Transitions through the Android Framework
Chen, Yan
EdgeMiner: Automatically Detecting Implicit Control Flow Transitions through the Android Framework of Android applications. One of the building blocks that these analysis systems rely upon is the computation of a precise control flow graph. The callback mechanism provided and orchestrated by the Android framework
Banerjee, Soumya Jyoti; Roy, Soumen
2014-01-01
There have been many studies on malicious targeting of network nodes using degree, betweenness etc. We propose a new network metric, edge proximity, ${\\cal P}_e$, which demonstrates the importance of specific edges in a network, hitherto not captured by existing network metrics. Effects of removing edges with high ${\\cal P}_e$ might initially seem inconspicuous but is eventually shown to be very harmful for the network. When compared to existing strategies, removal of edges by ${\\cal P}_e$, leads to remarkable increase of diameter and average path length in real and random networks till the first disconnection and beyond. ${\\cal P}_e$ can be consistently used to rupture the network into two nearly equal parts, thus presenting a very potent strategy to greatly harm a network. Targeting by ${\\cal P}_e$ causes notable efficiency loss in US and European power grid. ${\\cal P}_e$ identifies proteins with essential cellular functions in protein-protein interaction networks. It pinpoints regulatory neural connections...
u:\\designs\\edge_detector\\documentation\\ How ED and ED48 Work-Rev2.doc
and each can hold four 8-bit words. Eight-bits limits the leading edges to 255 and less for transitions in three groups. The first group (A) looks for a specific pattern starting in bits 9-6, the second group (B) looks at bits 5-2 and the third group (C) looks at bits 1-0. The exact pattern
CUTTING-EDGE TECHNOLOGY The new Faculty of Engineering and IT building is home to world-
University of Technology, Sydney
CUTTING-EDGE TECHNOLOGY The new Faculty of Engineering and IT building is home to world- leading university in the world to offer this program in collaboration with Alcatel-Lucent. The Centre for Real collection of environmental and biometric sensors. WORLD-LEADING RESEARCH The Australian Research Council
Low Velocity Boron Micro-Pellet Injector For Edge And Core Impurity Transport Measurements
1 Low Velocity Boron Micro-Pellet Injector For Edge And Core Impurity Transport Measurements H. W, Baltimore, Maryland 21218 Abstract A simple Low Velocity Boron Micro-Pellet Injector has been under High velocity, pneumatic, pellet injection systems are applied routinely for injecting frozen pellets
The dynamic response of edge clamped plates loaded by spherically expanding sand shellsq
Wadley, Haydn
The dynamic response of edge clamped plates loaded by spherically expanding sand shellsq Kumar P and water saturated sand has been investigated, both experimentally and via a particle based simulation methodology. The spherically expanding sand shell is generated by detonating a sphere of explosive surrounded
OCTOBER1997 THE LEADING EDGE 1429 Tight, low-porosity reservoirs can produce significant
Tsvankin, Ilya
reservoirs using surface seismic data is an important exploration problem that has attracted much attention impor- tant to obtain more information about fractured reser- voirs from 3-D P-wave data. AmpliOCTOBER1997 THE LEADING EDGE 1429 Tight, low-porosity reservoirs can produce significant amounts
H e a v y o i l 1116 The Leading Edge September 2008
H e a v y o i l 1116 The Leading Edge September 2008 Modeling studies of heavy oil--in between solid and fluid properties Rocks filled with heavy oil do not comply with established theories for porous media. Heavy oils demonstrate a blend of both purely viscous and purely elastic properties, also
Tiree Energy Pulse: Exploring Renewable Energy Forecasts on the Edge of the Grid
MacDonald, Mark
Tiree Energy Pulse: Exploring Renewable Energy Forecasts on the Edge of the Grid Will Simm1 , Maria energy consumption with supply, and together built a prototype renewable energy forecast display. A num local renewable energy was expected to be available, despite having no financial in- centive to do so
Imaging Inter-Edge State Scattering Centers in the Quantum Hall Regime Michael T. Woodside,1
McEuen, Paul L.
, University of California and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 2 Materials Department, University of California, Santa Barbara, California 93106 (February of the spatial structure in a 2DEG on electron transport by examining the nature of the scattering between edge
On the non-stiffness of edge transport in L-mode tokamak plasmas
Sauter, O.; Brunner, S.; Kim, D.; Merlo, G.; Behn, R.; Coda, S.; Duval, B. P.; Federspiel, L.; Goodman, T. P.; Karpushov, A.; Merle, A.; Team, TCV, E-mail: olivier.sauter@epfl.ch [Centre de Recherches en Physique des Plasmas, Association EURATOM-Confédération Suisse, EPFL, PPB-Ecublens, 1015 Lausanne (Switzerland); Camenen, Y. [CNRS, UMR 7345, Aix-Marseille Université, Marseille (France)
2014-05-15
Transport analyses using first-principle turbulence codes and 11/2 -D transport codes usually study radial transport properties between the tokamak plasma magnetic axis and a normalized minor radius around 0.8. In this region, heat transport shows significantly stiff properties resulting in temperature scalelength values (R?L{sub T}) that are relatively independent of the level of the radial heat flux. We have studied experimentally in the tokamak ą configuration variable [F. Hofmann et al., Plasma Phys. Controlled Fusion 36, B277 (1994)] the radial electron transport properties of the edge region, close to the last closed flux surface, namely, between ?{sub V}=?(V/V{sub edge})=0.8 to 1. It is shown that electron transport is not stiff in this region and high R?L{sub Te} values (?2040) can be attained even for L-mode confinement. We can define a pedestal location, already in L-mode regimes, where the transport characteristics change from constant logarithmic gradient, inside ?{sub V}?=?0.8, to constant gradient between 0.8 and 1.0. In particular, we demonstrate, with well resolved T{sub e} and n{sub e} profiles, that the confinement improvement with plasma current I{sub p}, with or without auxiliary heating, is due to this non-stiff edge region. This new result is used to explain the significant confinement improvement observed with negative triangularity, which could not be explained by theory to date. Preliminary local gyrokinetic simulations are now consistent with an edge, less stiff, region that is more sensitive to triangularity than further inside. We also show that increasing the electron cyclotron heating power increases the edge temperature inverse scalelength, in contrast to the value in the main plasma region. The dependence of confinement on density in ohmic plasmas is also studied and brings new insight in the understanding of the transition between linear and saturated confinement regimes, as well as of the density limit and appearance of a 2/1 tearing mode. The results presented in this paper provide an important new perspective with regards to radial transport in tokamak plasmas which goes beyond L-mode plasmas and explains some previous puzzling results. It is proposed that understanding the transport properties in this edge non-stiff region will also help in understanding the improved and high confinement edge properties.
Spectrally narrowed leaky waveguide edge emission and transient electrluminescent dynamics of OLEDs
Zhengqing, Gan
2010-05-16
In summary, there are two major research works presented in this dissertation. The first research project (Chapter 4) is spectrally narrowed edge emission from Organic Light Emitting Diodes. The second project (Chapter 5) is about transient electroluminescent dynamics in OLEDs. Chapter 1 is a general introduction of OLEDs. Chapter 2 is a general introduction of organic semiconductor lasers. Chapter 3 is a description of the thermal evaporation method for OLED fabrication. The detail of the first project was presented in Chapter 4. Extremely narrowed spectrum was observed from the edge of OLED devices. A threshold thickness exists, above which the spectrum is narrow, and below which the spectrum is broad. The FWHM of spectrum depends on the material of the organic thin films, the thickness of the organic layers, and length of the OLED device. A superlinear relationship between the output intensity of the edge emission and the length of the device was observed, which is probably due to the misalignment of the device edge and the optical fiber detector. The original motivation of this research is for organic semiconductor laser that hasn't been realized due to the extremely high photon absorption in OLED devices. Although we didn't succeed in fabricating an electrically pumped organic laser diode, we made a comprehensive research in edge emission of OLEDs which provides valuable results in understanding light distribution and propagation in OLED devices. Chapter 5 focuses on the second project. A strong spike was observed at the falling edge of a pulse, and a long tail followed. The spike was due to the recombination of correlated charge pair (CCP) created by trapped carriers in guest molecules of the recombination zone. When the bias was turned off, along with the decreasing of electric field in the device, the electric field induced quenching decreases and the recombination rate of the CCP increases which result in the spike. This research project provides a profound understanding of the EL dynamics of OLED, and the theoretical model can fit and explain the experiment data quite well. For the edge emission, we focused on the spectrum and the relative intensity of the edge emission. In the future, more research can be done on the comparison of the intensity between the total edge emission and the surface emission which will give us a sense what fraction of light was trapped in the device. Micro structures can be integrated into the OLED such as DFB and DBR, the character of edge emission should be very interesting. For the transient spike, the CCP model can give a good explanation. But in the model, the effect of the electric field change is not included, because from the start point (t=0), we assume the mobility of carriers is a constant. If we consider the details of the change of the electric field, then when turning of the bias, the decrease of the electric field results in decrease of the carrier mobility and the dissociation rate. If we can add the electric field effect into the model, the whole theory will be more convincing.
Measurement of Molecular Deuterium Fluxes in the DIII-D Edge
Hollmann, E; Brezinsek, S; Brooks, N; Groth, M; Lisgo, S; McLean, A; Pigarov, A Y; Rudakov, D
2005-06-24
In hydrogen-fueled tokamak discharges, the distribution of molecular hydrogen (or deuterium) in the plasma edge region plays a central role in edge fueling, affecting pedestal shape and core density control [1]. In addition to its role in edge fueling, molecular hydrogen is important for plasma edge atomic physics. An example of this is the enhancement of plasma volume recombination known to occur in the presence of vibrationally-excited hydrogen molecules via conversion of H{sup +} ions into molecular ions such as H{sub 2}{sup +} and H{sub 3}{sup +} [2]. Here, measurements of the D{sub 2} molecule flux into the far edge/scrape-off layer (SOL) of the DIII-D tokamak are made using passive visible spectroscopy of the D{sub 2} diagonal Fulcher band (3p-2s triplet Q-branch) line emission over the range {lambda} = 600.640 nm [3]. L-mode, lower-single-null discharges are studied. A multi-chord visible spectrometer with views of both lower divertor legs and the main chamber is used [4]. A schematic of the spectrometer view chords used here, as well as typical magnetic flux surfaces, midplane probe location, and Thomson scattering view locations, are shown in Fig. 1. As a convenient variable to describe the location of each view chord, the poloidal angle {theta} of the corresponding emission volume is used (Fig. 1). Each view chord crosses the SOL twice; in the case of the upper view chords and lower view chords, the emission from the SOL closer to the lower divertor is expected to dominate the measured signal. In the case of the midplane view chord, lineshape (Zeeman splitting) analysis of the D{sub {alpha}} line indicates that the received emission is typically dominated by the inner wall SOL (over the outer wall SOL by {approx} 2-8x).
Ghosh, Sandip
Edge-emission electroluminescence study of as-grown vertical-cavity surface-emitting laser 22 April 2000 We report polarized edge- and front-emission electroluminescence studies on red on pieces of as-grown wafers using indiumtinoxide-coated glass electrodes. The front-emission spectra
Zuschin, Martin
Effects of a high-risk environment on edge-drilling behavior: inference from Recent bivalves from the Red Sea Devapriya Chattopadhyay, Martin Zuschin, and Adam Tomasov“ych Abstract.--Edge-drilling is an unusual predation pattern in which a predatory gastropod drills a hole on the commissure between
Paxton, Anthony T.
-stabilized zirconia S. Ostanin,1,2, * A. J. Craven,1 D. W. McComb,2 D. Vlachos,1,2, A. Alavi,3 A. T. Paxton,4 and M. W-edge structure ELNES at the O K edge has been studied in yttria-stabilized zirconia YSZ . The electronic
Cooking with Trail Mix (Spanish)
Anding, Jenna
2008-12-09
de az?car ? taza de pur? de manzana 2 cucharadas de aceite vegetal 1 huevo ? cantidad necesaria de leche 1 taza de harina de uso general ? cucharadita de bicarbonato de sodio ? cucharadita de polvo para hornear ? de cucharadita de canela (si gusta...) ? de taza de mezcla de frutos secos Ingredientes ? taza de harina de uso general ? taza de polvo para hornear ? cucharadita de sal 2 huevos ? taza de az?car ? cucharadita de vainilla 1? taza de mezcla de...
Unknown
2011-09-05
The objective of this study was to investigate the relationship between the attitudes of parents toward outdoor environments and their children spending time outdoors, and how these attitudes related to their children's overall health. The sample...
TREE TRAILS Annual Benefits Breakdown
side of a building can warm inside spaces. Trees slow down winds around buildings and help decrease heat loss. Find an animated model showing trees around a house at 1. http://treebenefits.com/calculator/ USDA Forest Service Center for Urban Forest Research http://www.fs.fed.us/psw/programs/uesd/uep/ Arbor
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Settler's Trail | Open Energy Information
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Pioneer Trail | Open Energy Information
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TWP Island Cloud Trail Studies
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With LivermoreSustainableDEPARTMENT OFEnergy-8,nTWIST tours TWIST
Prediction of PFC Plasma Fluxes by Improved Edge/Scrape-off-layer Simulations
Rognlien, T
2009-02-26
Large, localized plasma heat exhaust, subsequent inward transport of eroded impurities, and distribution of tritium to walls comprise one of the most critical class of problems for the development of tokamak fusion reactors. The magnitude and temporal duration of the heat fluxes is controlled by two factors: (1) the plasma power coming into the edge from the core, and (2), the physics processes in the edge/scrape-off-layer (SOL) that distribute the power to Plasma Facing Components (PFCs), both in space and in time. Given that the plasma power is largely determined by the fusion power desired, here I address model development needs for item (2), the distribution of power to PFCs, which naturally carries with it the capability for transport of impurities and tritium. Another key issue not addressed here is the impact of edge plasma transport on the plasma pedestal parameters. The nature of plasma transport in the edge/SOL region has long be differentiated from that in the bulk core, initially because of the larger fluctuation amplitudes that are observed, with density fluctuations relative to the time-average sometimes approaching as high as unity in the SOL. More recent measurements have shown addition effects such as strong intermittency, filamentation, toroidal asymmetry, and large flows [1]. These characteristics have a direct impact on plasma energy and particle fluxes to PFCs and on the flow of impurities in the edge. The theory of the edge/SOL is complicated by the steep gradients, multi-dimensional nature of plasma/neutral variations, and as mentioned above, the strong relative fluctuation levels compared to the core region. Furthermore, the strong interaction of the plasma with neutrals and the associated radiative effects for partially ionized plasma are important, Consequently, theoretical models typically need to be, or should be, more complicated, which may be one reason model development has lagged that in the core (funding being another reason). Simulation models of the edge/SOL can be divided into transport codes, which give the slow evolution of the plasma profiles and fluxes in a complex environment, and turbulence codes, which model the unstable, strongly fluctuating plasma state and thus (ideally) provide transport coefficients to the transport codes; this latter connect has only been made for a very limited set of simulations. The edge transport codes are either 2D fluid or now emerging 4D (2r,2v) kinetic. The turbulence codes are 2D and 3D fluid (only one U.S. 3D code spans the separatrix), and emerging 5D gyrokinetic codes. Many of the transport simulations to model plasma fluxes use ad hoc radial transport coefficients, rendering them more in the class of 'interpretive' simulations, not predictive; this limitation makes fundamental prediction for heat-flux widths and edge/SOL transport in general unobtainable at present. Even if there was a strong connection made between transport and turbulence codes, there is not yet a clear consensus in the community concerning the controlling instabilities and turbulence features, even for fixed plasma profiles. In comparison, the core turbulence simulations/theory/experiment have standard benchmarks (e.g., the Cyclone case), agree on many aspects of the big picture of the dominant ion transport, and have made good progress on electron transport. Again this core/edge difference can at least partially be traced to both the inherent difficulty of the edge problem and the stronger historical support for core simulation development; as the edge issue for high-power devices increases in importance, the funding prior should be change. No theory/simulation can be trusted without substantial experimental validation. The edge/SOL area is physically more accessible, but also more complex (2D-3D variations) and also different plasma parameters than for core diagnostics. Among the valuable diagnostics for transport are IRTV, thermocouples, Langmuir probes (but with maximum incident plasma power limitations), Thomson scattering, and visible. For turbulence diagnostics, we h
Plot/SurfW: Plotting Utility for EDGE2D Output
W.M. Davis and J.D. Strachan
2012-06-22
This report describes a utility that was developed to display EDGE2D results. The utility is focused on results that relate to impurity density, velocity, and particle fluxes in the SOL and divertor. Due to the complicated nature of 2D impurity sources, the concentration of the thermal force near the separatrix and near the divertor entrance, the impurity flow pattern and impurity densities are not necessarily easy to visualize. Thus, we wanted a utility that allowed simple and quick visualization of the impurity behavior. In order to achieve this we overlaid the divertor hardware for plots inside the divertor and we expanded the appearance of the main chamber SOL by plotting distance along the field lines vs. SOL depth with the density (or velocity or flux or other quantity) the false colour. Also, we allowed for the plotted variable to be a function of the other EDGE2D result variables. __________________________________________________
Leung, Kevin
2015-01-01
The applied potential governs lithium-intercalation and electrode passivation reactions in lithium ion batteries, but are challenging to calibrate in condensed phase DFT calculations. In this work, the "anode potential" of charge-neutral lithium-intercalated graphite (LiC(6)) with oxidized edge planes is computed as a function of Li-content n(Li)) at edge planes, using ab initio molecular dynamics (AIMD), a previously introduced Li+ transfer free energy method, and the experimental Li+/Li(s) value as reference. The voltage assignments are corroborated using explicit electron transfer from fluoroethylene carbonate radical anion markers. PF6- is shown to decompose electrochemically (i.e., not just thermally) at low potentials imposed by our voltage calibration technique. We demonstrate that excess electrons reside in localized states-in-the-gap in the organic carbonate liquid region, which is not semiconductor-like (band-state-like) as widely assumed in the literature.
SXR-XUV Diagnostics for Edge and Core of Magnetically Confined Plasmas
Stutman, Dan
2014-09-10
The present report summarizes the results obtained during a one-year extension of DoE grant SXR-XUV Diagnostics for Edge and Core of Magnetically Confined Plasmas, at Johns Hopkins University, aimed at completing the development of a new type of magnetic fusion plasma diagnostic, the XUV Transmission Grating Imaging Radiometer (TGIR). The TGIR enables simultaneous spatially and spectrally resolved measurements of the XUV/VUV radiated power from impurities in fusion plasmas, with high speed. The instrument was successfully developed and qualified in the laboratory and in experiments on a tokamak. Its future applications will be diagnostic of the impurity content and transport in the divertor and edge of advanced magnetic fusion experiments, such as NSTX Upgrade.
Effect of non-diffusive processes on transport and its interpretation in the tokamak plasma edge
Stacey, Weston M. [Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)] [Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)
2013-11-15
An interpretive methodology improved to account for two non-diffusive transport mechanismsparticle pinch and ion orbit losswas applied to interpret the difference in transport (i) between a discharge with Resonance Magnetic Perturbations and a High confinement mode discharge with otherwise identical operating parameters and (ii) between the Low confinement and High confinement phases of a discharge free of Edge Localized Modes. Differences in particle and energy diffusion coefficients and in the particle pinch were inferred from the experimental data, and the inferred experiment thermal diffusion coefficients were compared with various theoretical predictions. The effect of taking ion orbit loss into account in the interpretation was quantified, and the possible relation of ion orbit loss to the observed transport edge shortfall is discussed.
Nonlinear three-mode interaction and drift-wave turbulence in a tokamak edge plasma
Batista, A.M.; Caldas, I.L.; Lopes, S.R.; Viana, R.L.; Horton, W.; Morrison, P.J. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970, Sao Paulo, SP (Brazil); Departamento de Fisica, Universidade Federal do Parana, 81531-990, Curitiba, Parana (Brazil); Department of Physics and Institute for Fusion Studies, University of Texas at Austin, Austin, Texas, 78712 (United States)
2006-04-15
A three-wave interaction model with quadratic nonlinearities and linear growth/decay rates is used to investigate the occurrence of drift-wave turbulence driven by pressure gradients in the edge plasma of a tokamak. Model parameters are taken from a typical set of measurements of the floating electrostatic potential in the tokamak edge region. Some aspects of the temporal dynamics exhibited by the three-wave interaction model are investigated, with special emphasis on a chaotic regime found for a wide range of the wave decay rate. An intermittent transition from periodic to chaotic behavior is observed and some statistical properties, such as the interburst and laminar length interval durations, are explored.
Krepel, Dana
2013-01-01
The effects of edge chemistry on the relative stability and electronic properties of zigzag boron nitride nanoribbons (ZBNNRs) are investigated. Among all functional groups considered, fully hydroxylated ZBNNRs are found to be the most energetically stable. When an in-plane external electric field is applied perpendicular to the axis of both hydrogenated and hydroxylated ZBNNRs, a spin-polarized half-metallic state is induced, whose character is different than that predicted for ZGNRs. The onset field for achieving the half-metallic state is found to mainly depend on the width of the ribbon. Our results indicate that edge functionalization of ZBNNRs may open the way for the design of new nano-electronic and nano-spintronic devices.
Topological Massive Dirac Edge Modes and Long-Range Superconducting Hamiltonians
O. Viyuela; D. Vodola; G. Pupillo; M. A. Martin-Delgado
2015-11-16
We discover novel topological effects in the one-dimensional Kitaev chain modified by long-range Hamiltonian deformations in the hopping and pairing terms. This class of models display symmetry-protected topological order measured by the Berry phase of the ground state and the winding number of the Hamiltonians. For exponentially-decaying hopping amplitudes, the topological sector can be significantly augmented as the penetration length increases, something experimentally achievable. For power-law decaying superconducting pairings, the massless Majorana modes at the edges get paired together into a massive non-local Dirac fermion localised at both edges of the chain: a new topological quasiparticle that we call topological massive Dirac fermion. This topological phase has fractional topological numbers as a consequence of the long-range couplings. Possible applications to current experimental setups and topological quantum computation are also discussed.
Shape-controlled orientation and assembly of colloids with sharp edges in nematic liquid crystals
Daniel A. Beller; Mohamed A. Gharbi; Iris B. Liu
2014-12-12
The assembly of colloids in nematic liquid crystals via topological defects has been extensively studied for spherical particles, and investigations of other colloid shapes have revealed a wide array of new assembly behaviors. We show, using Landau-de Gennes numerical modeling, that nematic defect configurations and colloidal assembly can be strongly influenced by fine details of colloid shape, in particular the presence of sharp edges. For cylinder, microbullet, and cube colloid geometries, we obtain the particles' equilibrium alignment directions and effective pair interaction potentials as a function of simple shape parameters. We find that defects pin at sharp edges, and that the colloid consequently orients at an oblique angle relative to the far-field nematic director that depends on the colloid's shape. This shape-dependent alignment, which we confirm in experimental measurements, raises the possibility of selecting self-assembly outcomes for colloids in liquid crystals by tuning particle geometry.
Chang, C C; Cheng, C Z
2013-01-01
Particle and heat transport in tokamak edge is investigated by guiding center orbit following calculation. The guiding center equation is solved for both electrons and ions in the presence of magnetic perturbation. It is suggested that the remnants of the magnetic islands play a role in characterizing the radial transport. The transport coefficient is estimated which also demonstrate local structure in the vicinity of magnetic islands.
Shot-noise at a Fermi-edge singularity: Non-Markovian dynamics
Ubbelohde, N.; Maire, N.; Haug, R. J.; Roszak, K.; Hohls, F.; Novotnż, T.
2013-12-04
For an InAs quantum dot we study the current shot noise at a Fermi-edge singularity in low temperature cross-correlation measurements. In the regime of the interaction effect the strong suppression of noise observed at zero magnetic field and the sequence of enhancement and suppression in magnetic field go beyond a Markovian master equation model. Qualitative and quantitative agreement can however be achieved by a generalized master equation model taking non-Markovian dynamics into account.
LIGHT SUBGRAPHS IN PLANAR GRAPHS OF MINIMUM DEGREE 4 AND EDGE-DEGREE 9
Mohar, Bojan
LIGHT SUBGRAPHS IN PLANAR GRAPHS OF MINIMUM DEGREE 4 AND EDGE-DEGREE 9 B. MOHAR , R. SKREKOVSKI vertices of degree 4 are adjacent. A graph H is light in G if there is a constant w such that every graph is w. Then we also write w(H) w. It is proved that the cycle Cs is light if and only if 3 s 6, where
On gas desorption from the tokamak first wall during edge localized modes
Marenkov, E. D., E-mail: edmarenkov@gmail.com [National Nuclear Research University Moscow Engineering and Physics Institute (Russian Federation); Smirnov, R. D.; Krasheninnikov, S. I. [University of California, San Diego (United States)] [University of California, San Diego (United States)
2013-11-15
The effect of gas desorption from the tokamak first wall on the pedestal recovery in the H-mode after an edge-localized-mode burst is considered. Results of FACE code simulations of hydrogen desorption from a beryllium wall are presented. It is found that the wall has a significant effect on plasma processes only at sufficiently low temperatures (of about 400 K), which agrees with qualitative estimates obtained earlier in the zero-dimensional approximation.
McCaulley, J.A. (Hoechst Celanese Research Division, Robert L. Mitchell Technical Center, 86 Morris Avenue, Summit, New Jersey 07901 (United States))
1993-03-01
Pd [ital K]-edge extended x-ray-absorption fine-structure (EXAFS) and x-ray-absorption near-edge-structure (XANES) measurements were performed on a Pd carbide phase, PdC[sub [ital x
The pinch of cold ions from recycling in the tokamak edge pedestal
Wan Weigang; Parker, Scott E.; Chen Yang; Park, Gun-Young; Chang, Choong-Seock; Stotler, Daren
2011-05-15
We apply the ''natural fueling mechanism'' [W. Wan, S. E. Parker, Y. Chen, and F. W. Perkins, Phys. Plasmas 17, 040701 (2010)] to the edge pedestal. The natural fueling mechanism is where cold ions naturally pinch radially inward for a heat-flux dominated plasma. It is shown from neoclassical-neutral transport coupled simulations that the recycling neutrals and the associated source ions are colder than the main ions in the edge pedestal. These recycling source ions will pinch radially inward due to microturbulence. Gyrokinetic turbulence simulations indicate that near the top of the pedestal, the pinch velocity of the recycling source ions is much higher than the main ion outgoing flow velocity. The turbulent pinch of the recycling source ions may play a role in the edge pedestal transport and dynamics. The cold ion temperature significantly enhances the pinch velocity of the recycling source ions near to the pedestal top. Neoclassical calculations show a cold ion pinch in the pedestal as well.
Fully Nonlinear Edge Gyrokinetic Simulations of Kinetic Geodesic-Acoustic Modes and Boundary Flows
Xu, X Q; Belli, E; Bodi, K; Candy, J; Chang, C S; Cohen, B I; Cohen, R H; Colella, P; Dimits, A M; Dorr, M R; Gao, Z; Hittinger, J A; Ko, S; Krasheninnikov, S; McKee, G R; Nevins, W M; Rognlien, T D; Snyder, P B; Suh, J; Umansky, M V
2008-09-18
We present edge gyrokinetic neoclassical simulations of tokamak plasmas using the fully nonlinear (full-f) continuum code TEMPEST. A nonlinear Boltzmann model is used for the electrons. The electric field is obtained by solving the 2D gyrokinetic Poisson Equation. We demonstrate the following: (1) High harmonic resonances (n > 2) significantly enhance geodesic-acoustic mode (GAM) damping at high-q (tokamak safety factor), and are necessary to explain both the damping observed in our TEMPEST q-scans and experimental measurements of the scaling of the GAM amplitude with edge q{sub 95} in the absence of obvious evidence that there is a strong q dependence of the turbulent drive and damping of the GAM. (2) The kinetic GAM exists in the edge for steep density and temperature gradients in the form of outgoing waves, its radial scale is set by the ion temperature profile, and ion temperature inhomogeneity is necessary for GAM radial propagation. (3) The development of the neoclassical electric field evolves through different phases of relaxation, including GAMs, their radial propagation, and their long-time collisional decay. (4) Natural consequences of orbits in the pedestal and scrape-off layer region in divertor geometry are substantial non-Maxwellian ion distributions and flow characteristics qualitatively like those observed in experiments.
Alexander Carmele; Markus Heyl; Christina Kraus; Marcello Dalmonte
2015-07-22
We investigate the resilience of symmetry-protected topological edge states at the boundaries of Kitaev chains in the presence of a bath which explicitly introduces symmetry-breaking terms. Specifically, we focus on single-particle losses and gains, violating the protecting parity symmetry, which could generically occur in realistic scenarios. In homogeneous systems, we show that the Majorana mode decays exponentially fast. However, we find that it is possible to substantially increase its life-time by eliminating the dissipative dynamics close to the edges. Most importantly, we demonstrate that the Majorana mode can be further stabilized by the inclusion of disorder where the decay of the Majorana converts into a stretched exponential form implying an exponential gain in stability compared to the homogeneous case. In particular, for pure loss dynamics we find a universal exponent $\\alpha \\simeq 2/3$. We show that this holds both in the Anderson and many-body localized regimes. Our results thus provide a concrete recipe to stabilize edge states even in the presence of symmetry-breaking environments.
Zhang, Xi; Wang, Chao; Diao, Dongfeng; Sun, Chang Q
2014-07-28
In this paper, we clarified a robust mechanism of magnetism generated by excess electrons captured by edge-quantum well of diamagnetic armchair edges. Consistency between density functional theory calculations and electron cyclotron resonance experiments verified that: (1) Multi-layer armchair nanoribbons are stable with proper amounts of excess electrons which can provide net spin; (2) Since under-coordination induces lattice relaxation and potential well modulation, electrons tend to be trapped at edges; and (3) Neither large amount of excess electrons nor positive charges can induce magnetism. This work shed light on the development of graphene devices in its magnetic applications.
Disruption avoidance in the SINP-Tokamak by means of electrode-biasing at the plasma edge
Basu, Debjyoti [Saha Institute of Nuclear Physics, 1/AF-Bidhannagar, Kolkata 700064, WB (India) [Saha Institute of Nuclear Physics, 1/AF-Bidhannagar, Kolkata 700064, WB (India); Instituto de Ciencias Nucleares-UNAM, Mexico D.F. 04510 (Mexico); Pal, Rabindranath [Saha Institute of Nuclear Physics, 1/AF-Bidhannagar, Kolkata 700064, WB (India)] [Saha Institute of Nuclear Physics, 1/AF-Bidhannagar, Kolkata 700064, WB (India); Martinell, Julio J. [Instituto de Ciencias Nucleares-UNAM, Mexico D.F. 04510 (Mexico)] [Instituto de Ciencias Nucleares-UNAM, Mexico D.F. 04510 (Mexico); Ghosh, Joydeep; Chattopadhyay, Prabal K. [Institute for Plasma Research, Gandhinagar (India)] [Institute for Plasma Research, Gandhinagar (India)
2013-05-15
Control of plasma disruption by a biased edge electrode is reported in SINP-Tokamak. The features that characterize a plasma disruption are reduced with increasing bias potential. The disruption can be completely suppressed with the concomitant stabilization of observed MHD modes that are allegedly precursors of the disruption. An m = 3/n = 1 tearing mode, which apparently causes disruption can be stabilized when a negative biasing potential is applied near the edge. These changes in the disruptive behavior with edge biasing are hypothesized to be due to changes in the current density profile.
Sheldon, Nathan D.
"The Dangerous Edge of Things": John Webster's Bosola in Context & Performance © John F Buckingham May 2011 #12;"The Dangerous Edge of Things": John Webster's Bosola in Context & Performance © John F, this is always clearly stated. Signed: ______________________ Date: 18th May 2011 #12;"The Dangerous Edge
Crate, Frances Margaret
1997-01-01
This study examined the development of Clear Lake-NASA Area, Texas into an edge city and challenged the Garreau edge city model by addressing the question, Do all edge cities follow the Garreau model of development? ...
Zhang, Guangyu
Graphene Edge Lithography Guibai Xie, Zhiwen Shi, Rong Yang, Donghua Liu, Wei Yang, Meng Cheng: Fabrication of graphene nanostructures is of importance for both investigating their intrinsic physical approach for graphene nanostructures. Compared with conventional lithographic fabrication techniques
Development of a gamma-ray detector with iridium transition edge sensor coupled to a Pb absorber
Leman, Steven W.
We have recently started to develop a high-resolution gamma-ray spectrometer for material defect analysis. Our gamma-ray detector is a microcalorimeter consisting of an iridium/gold bilayer transition edge sensor (TES) ...
Igor Romanovsky; Constantine Yannouleas; Uzi Landman
2009-01-15
We investigate the way that the degenerate manifold of midgap edge states in quasicircular graphene quantum dots with zig-zag boundaries supports, under free-magnetic-field conditions, strongly correlated many-body behavior analogous to the fractional quantum Hall effect (FQHE), familiar from the case of semiconductor heterostructures in high magnetic fields. Systematic exact-diagonalization (EXD) numerical studies are presented for the first time for 5 graphene REMs exhibit in all instances a single (0,N) polygonal-ring molecular (crystalline) structure, with all the electrons localized on the edge. Disruptions in the zig-zag boundary condition along the circular edge act effectively as impurities that pin the electron molecule, yielding single-particle densities with broken rotational symmetry that portray directly the azimuthal localization of the edge electrons.
Gangadhara, Sanjay, 1972-
2003-01-01
A unique system has been developed for studying impurity transport in the edge plasma of Alcator C-Mod. Impurity gas (which for these experiments is deuterated ethylene, C?D?) is injected locally into the scrape-off layer ...
Yeary, Mark Bradley
1994-01-01
The purpose of this research was to design a spatial domain convolution filter capable of directional edge detection which has a specific relationship to a pre-defined filter in the frequency domain. Nobody has designed a directional filter...
Probing single magnon excitations in Sr?IrO? using O K-edge resonant inelastic x-ray scattering
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Liu, X. [Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics (BNLCP-CAS); Brookhaven National Lab. (BNL), Upton, NY (United States); Collaborative Innovation Center of Quantum Matter, Beijing (China); Dean, M. P. M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Liu, J. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chiuzbaian, S. G. [Sorbonne Univ., Paris (France); Synchrotron SOLEIL, Saint-Aubin (France); Jaouen, N. [Synchrotron SOLEIL, Saint-Aubin (France); Nicolaou, A. [Synchrotron SOLEIL, Saint-Aubin (France); Yin, W. G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Rayan Serrao, C. [Univ. of California, Berkeley, CA (United States); Ramesh, R. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ding, H. [Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics (BNLCP-CAS); Collaborative Innovation Center of Quantum Matter, Beijing (China); Hill, J. P. [Brookhaven National Lab. (BNL), Upton, NY (United States)
2015-05-27
Resonant inelastic X-ray scattering (RIXS) at the L-edge of transition metal elements is now commonly used to probe single magnon excitations. Here we show that single magnon excitations can also be measured with RIXS at the K-edge of the surrounding ligand atoms when the center heavy metal elements have strong spin-orbit coupling. This is demonstrated with oxygen K-edge RIXS experiments on the perovskite Sr?IrO?, where low energy peaks from single magnon excitations were observed. This new application of RIXS has excellent potential to be applied to a wide range of magnetic systems based on heavy elements, for which the L-edge RIXS energy resolutions in the hard X-ray region is usually poor.
Mukherjee, Souvik
2010-10-12
in both subsurface conductivity ? and relative permeability ?r. In this dissertation, I present a new three dimensional edgebased finite element (FE) algorithm capable of modeling the CSEM response of buried conductive and permeable targets. A coupled...
Access to a New Plasma Edge State with High Density and Pressures using Quiescent H-mode
Solomon, Wayne M.; Snyder, P. B.; Burrell, K. H.; Fenstermacher, M. E.; Garofalo, A. M.; Grierson, B. A.; Loarte, A.; McKee, G. R.; Nazikian, R; Osborne, T. H.
2014-07-01
A path to a new high performance regime has been discovered in tokamaks that could improve the attractiveness of a fusion reactor. Experiments on DIII-D using a quiescent H-mode edge have navigated a valley of improved edge peeling-ballooning stability that opens up with strong plasma shaping at high density, leading to a doubling of the edge pressure over standard edge localized mode (ELM)ing H-mode at these parameters. The thermal energy confinement time increases both as a result of the increased pedestal height and improvements in the core transport and reduced low-k turbulence. Calculations of the pedestal height and width as a function of density using constraints imposed by peeling-ballooning and kinetic-ballooning theory are in quantitative agreement with the measurements.
Seo, Janghoon; Choe, W.; Chang, C. S.; Ku, S.; Kwon, J. M.; Müller, Stefan H.
2014-09-15
Fluid Reynolds stress from turbulence has usually been considered to be responsible for the anomalous toroidal momentum transport in tokamak plasma. Experiment by Müller et al. [Phys. Rev. Lett. 106, 115001 (2011)], however, reported that neither the observed edge rotation profile nor the inward momentum transport phenomenon at the edge region of an H-mode plasma could be explained by the fluid Reynolds stress measured with reciprocating Langmuir-probe. The full-function gyrokinetic code XGC1 is used to explain, for the first time, Müller et al.'s experimental observations. It is discovered that, unlike in the plasma core, the fluid Reynolds stress from turbulence is not sufficient for momentum transport physics in plasma edge. The turbulent neoclassical physics arising from the interaction between kinetic neoclassical orbit dynamics and plasma turbulence is key in the tokamak edge region across the plasma pedestal into core.
Many body localization and quantum non-ergodicity in a model with a single-particle mobility edge
Xiaopeng Li; Sriram Ganeshan; J. H. Pixley; S. Das Sarma
2015-08-18
We investigate many body localization in the presence of a single particle mobility edge. By considering an interacting deterministic model with an incommensurate potential in one dimension we find that the single particle mobility edge in the noninteracting system leads to a many body mobility edge in the corresponding interacting system for certain parameter regimes. Using exact diagonalization, we probe the mobility edge via energy resolved entanglement entropy (EE) and study the energy resolved applicability (or failure) of the eigenstate thermalization hypothesis (ETH). Our numerical results indicate that the transition separating area and volume law scaling of the EE does not coincide with the non-thermal to thermal transition. Consequently, there exists an extended non-ergodic phase for an intermediate energy window where the many body eigenstates violate the ETH while manifesting volume law EE scaling. We also establish that the model possesses an infinite temperature many body localization transition despite the existence of a single particle mobility edge. We propose a practical scheme to test our predictions in atomic optical lattice experiments which can directly probe the effects of the mobility edge.
DEEP CHANDRA OBSERVATIONS OF EDGES AND BUBBLES IN THE NGC 5846 GALAXY GROUP
Machacek, Marie E.; Jerius, Diab; Kraft, Ralph; Forman, William R.; Jones, Christine; Randall, Scott [Harvard-Smithsonian Center for Astrophysics 60 Garden Street, Cambridge, MA 02138 (United States); Giacintucci, Simona [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Sun Ming, E-mail: mmachacek@cfa.harvard.edu [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22901 (United States)
2011-12-10
We use a combined 120 ks Chandra exposure to analyze X-ray edges produced by non-hydrostatic gas motions (sloshing) from galaxy collisions, and cavities formed by active galactic nucleus (AGN) activity. Evidence for gas sloshing is seen in the spiral morphology and multiple cold front edges in NGC 5846's X-ray surface brightness distribution, while the lack of spiral structure in the temperature map suggests that the perturbing interaction was not in the plane of the sky. Density and spectral modeling across the edges indicate that the relative motion of gas in the cold fronts is at most transonic. Evidence for AGN activity is seen in two inner bubbles at 0.6 kpc, filled with 5 GHz and 1.5 GHz radio plasma and coincident with H{alpha} emission, and in a ghost bubble at 5.2 kpc west of NGC 5846's nucleus. The outburst energy and ages for the inner (ghost) bubbles are {approx}10{sup 55} erg and {approx}2 Myr ({approx}5 Multiplication-Sign 10{sup 55} erg and 12 Myr), respectively, implying an AGN duty cycle of 10 Myr. The inner bubble rims are threaded with nine knots, whose total 0.5-2 keV X-ray luminosity is 0.3 Multiplication-Sign 10{sup 40} erg s{sup -1}, a factor {approx}2-3 less than that of the surrounding rims, and 0.7 keV mean temperature is indistinguishable from that of the rims. We suggest that the knots may be transient clouds heated by the recent passage of a shock from the last AGN outburst. We also observe gas stripping from a cE galaxy, NGC 5846A, in a 0.5 kpc long ({approx}10{sup 5} M{sub Sun }) hot gas tail, as it falls toward NGC 5846.
The Network Completion Problem: Inferring Missing Nodes and Edges in Networks
Kim, M; Leskovec, J
2011-11-14
Network structures, such as social networks, web graphs and networks from systems biology, play important roles in many areas of science and our everyday lives. In order to study the networks one needs to first collect reliable large scale network data. While the social and information networks have become ubiquitous, the challenge of collecting complete network data still persists. Many times the collected network data is incomplete with nodes and edges missing. Commonly, only a part of the network can be observed and we would like to infer the unobserved part of the network. We address this issue by studying the Network Completion Problem: Given a network with missing nodes and edges, can we complete the missing part? We cast the problem in the Expectation Maximization (EM) framework where we use the observed part of the network to fit a model of network structure, and then we estimate the missing part of the network using the model, re-estimate the parameters and so on. We combine the EM with the Kronecker graphs model and design a scalable Metropolized Gibbs sampling approach that allows for the estimation of the model parameters as well as the inference about missing nodes and edges of the network. Experiments on synthetic and several real-world networks show that our approach can effectively recover the network even when about half of the nodes in the network are missing. Our algorithm outperforms not only classical link-prediction approaches but also the state of the art Stochastic block modeling approach. Furthermore, our algorithm easily scales to networks with tens of thousands of nodes.
Orbital dynamics of three-dimensional bars: III. Boxy/Peanut edge-on profiles
P. A. Patis; Ch. Skokos; E. Athanassoula
2002-09-02
We present families, and sets of families, of periodic orbits that provide building blocks for boxy and peanut (hereafter b/p) edge-on profiles. We find cases where the b/p profile is confined to the central parts of the model and cases where a major fraction of the bar participates in this morphology. A b/p feature can be built either by 3D families associated with 3D bifurcations of the x1 family, or, in some models, even by families related with the z-axis orbits and existing over large energy intervals. The {\\sf `X'} feature observed inside the boxy bulges of several edge-on galaxies can be attributed to the peaks of successive x1v1 orbits (Skokos et al. 2002a, hereafter paper I), provided their stability allows it. However in general, the x1v1 family has to overcome the obstacle of a S\\ar\\D\\ar S transition in order to support the structure of a b/p feature. Other families that can be the backbones of b/p features are x1v4 and z3.1s. The morphology and the size of the boxy or peanut-shaped structures we find in our models is determined by the presence and stability of the families that support b/p features. The present study favours the idea that the observed edge-on profiles are the imprints of families of periodic orbits that can be found in appropriately chosen Hamiltonian systems, describing the potential of the bar.
Little, Mark P.; Stovall, Marilyn; Smith, Susan A.; Kleinerman, Ruth A.
2013-02-01
Purpose: To assess the shape of the dose response for various cancer endpoints and modifiers by age and time. Methods and Materials: Reanalysis of the US peptic ulcer data testing for heterogeneity of radiogenic risk by cancer endpoint (stomach, pancreas, lung, leukemia, all other). Results: There are statistically significant (P<.05) excess risks for all cancer and for lung cancer and borderline statistically significant risks for stomach cancer (P=.07), and leukemia (P=.06), with excess relative risks Gy{sup -1} of 0.024 (95% confidence interval [CI] 0.011, 0.039), 0.559 (95% CI 0.221, 1.021), 0.042 (95% CI -0.002, 0.119), and 1.087 (95% CI -0.018, 4.925), respectively. There is statistically significant (P=.007) excess risk of pancreatic cancer when adjusted for dose-response curvature. General downward curvature is apparent in the dose response, statistically significant (P<.05) for all cancers, pancreatic cancer, and all other cancers (ie, other than stomach, pancreas, lung, leukemia). There are indications of reduction in relative risk with increasing age at exposure (for all cancers, pancreatic cancer), but no evidence for quadratic variations in relative risk with age at exposure. If a linear-exponential dose response is used, there is no significant heterogeneity in the dose response among the 5 endpoints considered or in the speed of variation of relative risk with age at exposure. The risks are generally consistent with those observed in the Japanese atomic bomb survivors and in groups of nuclear workers. Conclusions: There are excess risks for various malignancies in this data set. Generally there is a marked downward curvature in the dose response and significant reduction in relative risk with increasing age at exposure. The consistency of risks with those observed in the Japanese atomic bomb survivors and in groups of nuclear workers implies that there may be little sparing effect of fractionation of dose or low-dose-rate exposure.
Plant Succession at the Edges of Two Abandoned Cultivated Fields on the Arid Lands Ecology Reserve
Simmons, Sally A. (OFFICE OF FELLOWSHIP PROG); Rickard, William H. (OFFICE OF FELLOWSHIP PROG)
2002-12-01
How vegetation recovers from disturbances is an important question for land managers. We examined 500 m2 plots to determine the progress made by native herbaceous plant species in colonizing the edges of abandoned cultivated fields at different elevations and microclimates, but with similar soils in a big sagebrush/bluebunch wheatgrass steppe. Alien species, especially cheatgrass and cereal rye, were the major competitors to the natives. The native species with best potential for restoring steppe habitats were sulphur lupine, hawksbeard, bottlebrush squirreltail, needle-and-thread grass, Sandberg's bluegrass, and several lomatiums.
In situ tomography of femtosecond optical beams with a holographic knife-edge
Strohaber, James; Kaya, G; N, Kay; Hart, Nathan; Kolomenskii, Alexander; Paulus, Gerhard; Schuessler, Hans
2011-07-18
? that are mechanically difficult or impossible to reproduce. We test our method by holographically knife-edging and tomographically reconstructing both continuous wave and broadband radiation in transverse optical modes. ?2011 Optical Society of America OCIS codes..., and C. J. G. J. Uiterwaal, ?Ultrashort intense-field optical vortices produced with laser-etched mirrors,? Appl. Opt. 46(36), 8583?8590 (2007). #146202 - $15.00 USD Received 19 Apr 2011; revised 2 Jul 2011; accepted 2 Jul 2011; published 12 Jul 2011...
Tree metrics and edge-disjoint S-paths Hiroshi Hirai (U. Tokyo)
Hirai, Hiroshi
: terminal set Āµ : (S 2 ) Z+: terminal weight a : E Z+: edge-cost G = (V, E)S P sP tP Āµ(sP , tP ) Def: S is a tree metric def tree , {ps}sS V , > 0 s.t. Āµ(s, t) = d (ps, pt) (s, t S). ps pt pu pv d (ps, pt: approx. algorithm for "near" tree metrics Problem: Āµ-EDP (cost-less version of Āµ-C
Final Report for the "Fusion Application for Core-Edge Transport Simulations (FACETS)"
Cary, John R; Kruger, Scott
2014-10-02
The FACETS project over its lifetime developed the first self-consistent core-edge coupled capabilities, a new transport solver for modeling core transport in tokamak cores, developed a new code for modeling wall physics over long time scales, and significantly improved the capabilities and performance of legacy components, UEDGE, NUBEAM, GLF23, GYRO, and BOUT++. These improved capabilities leveraged the teams expertise in applied mathematics (solvers and algorithms) and computer science (performance improvements and language interoperability). The project pioneered new methods for tackling the complexity of simulating the concomitant complexity of tokamak experiments.
High-resolution kaonic-atom x-ray spectroscopy with transition-edge-sensor microcalorimeters
S. Okada; D. A. Bennett; W. B. Doriese; J. W. Fowler; K. D. Irwin; S. Ishimoto; M. Sato; D. R. Schmidt; D. S. Swetz; H. Tatsuno; J. N. Ullom; S. Yamada
2014-02-19
We are preparing for an ultra-high resolution x-ray spectroscopy of kaonic atoms using an x-ray spectrometer based on an array of superconducting transition-edge-sensor microcalorimeters developed by NIST. The instrument has excellent energy resolutions of 2 - 3 eV (FWHM) at 6 keV and a large collecting area of about 20 mm^2. This will open new door to investigate kaon-nucleus strong interaction and provide new accurate charged-kaon mass value.
High-resolution kaonic-atom x-ray spectroscopy with transition-edge-sensor microcalorimeters
Okada, S; Doriese, W B; Fowler, J W; Irwin, K D; Ishimoto, S; Sato, M; Schmidt, D R; Swetz, D S; Tatsuno, H; Ullom, J N; Yamada, S
2014-01-01
We are preparing for an ultra-high resolution x-ray spectroscopy of kaonic atoms using an x-ray spectrometer based on an array of superconducting transition-edge-sensor microcalorimeters developed by NIST. The instrument has excellent energy resolutions of 2 - 3 eV (FWHM) at 6 keV and a large collecting area of about 20 mm^2. This will open new door to investigate kaon-nucleus strong interaction and provide new accurate charged-kaon mass value.
Nelson, G.J.; Chu, Y.; Harris, W.M.; Izzo, J.R.; Grew, K.N., Chiu, W.K.S.; Yi, J.; Andrews, J.C.; Liu, Y., Pierro, P.
2011-04-28
The reduction-oxidation cycling of the nickel-based oxides in composite solid oxide fuel cells and battery electrodes is directly related to cell performance. A greater understanding of nickel redox mechanisms at the microstructural level can be achieved in part using transmission x-ray microscopy (TXM) to explore material oxidation states. X-ray nanotomography combined with x-ray absorption near edge structure (XANES) spectroscopy has been applied to study samples containing distinct regions of nickel and nickel oxide (NiO) compositions. Digitally processed images obtained using TXM demonstrate the three-dimensional chemical mapping and microstructural distribution capabilities of full-field XANES nanotomography.
Development of a Leave-in-Place Slab Edge Insulating Form System
Marc Hoeschele; Eric Lee
2009-08-31
Concrete slabs represent the primary foundation type in residential buildings in the fast-growing markets throughout the southern and southwestern United States. Nearly 75% of the 2005 U.S. population growth occurred in these southern tier states. Virtually all of these homes have uninsulated slab perimeters that transfer a small, but steady, flow of heat from conditioned space to outdoors during the heating season. It is estimated that new home foundations constructed each year add 0.016 quads annually to U.S. national energy consumption; we project that roughly one quarter of this amount can be attributed to heat loss through the slab edge and the remaining three quarters to deep ground transfers, depending upon climate. With rising concern over national energy use and the impact of greenhouse gas emissions, it is becoming increasingly imperative that all cost-effective efforts to improve building energy efficiency be implemented. Unlike other building envelope components that have experienced efficiency improvements over the years, slab edge heat loss has largely been overlooked. From our vantage point, a marketable slab edge insulation system would offer significant benefits to homeowners, builders, and the society as a whole. Conventional slab forming involves the process of digging foundation trenches and setting forms prior to the concrete pour. Conventional wood form boards (usually 2 x 10's) are supported by vertical stakes on the outer form board surface, and by supporting 'kickers' driven diagonally from the top of the form board into soil outside the trench. Typically, 2 x 10's can be used only twice before they become waste material, contributing to an additional 400 pounds of construction waste per house. Removal of the form boards and stakes also requires a follow-up trip to the jobsite by the concrete subcontractor and handling (storage/disposal) of the used boards. In the rare cases where the slab is insulated (typically custom homes with radiant floor heating), the most practical insulation strategy is to secure rigid foam insulation, such as Dow Styrofoam{trademark}, to the inside of the wooden slab edge forms. An alternative is to clad insulation to the perimeter of the slab after the slab has been poured and cured. In either case, the foam must have a 'termite strip' that prevents termites from creating hidden tunnels through or behind the foam on their way to the wall framing above. Frequently this termite strip is a piece of sheet metal that must be fabricated for each project. The above-grade portion of the insulation also needs to be coated for appearance and to prevent damage from construction and UV degradation. All these steps add time, complexity, and expense to the insulating process.
The use of bulk states to accelerate the band edge statecalculation of a semiconductor quantum dot
Vomel, Christof; Tomov, Stanimire Z.; Wang, Lin-Wang; Marques,Osni A.; Dongarra, Jack J.
2006-05-10
We present a new technique to accelerate the convergence of the folded spectrum method in empirical pseudopotential band edge state calculations for colloidal quantum dots. We use bulk band states of the materials constituent of the quantum dot to construct initial vectors and a preconditioner. We apply these to accelerate the convergence of the folded spectrum method for the interior states at the top of the valence and the bottom of the conduction band. For large CdSe quantum dots, the number of iteration steps until convergence decreases by about a factor of 4 compared to previous calculations.
Pellet fuelling with edge-localised modes controlled by external magnetic perturbations in MAST
Valovic, M; Gurl, C; Kirk, A; Dunai, D; Field, A R; Lupelli, I; Naylor, G; Thornton, A
2014-01-01
The fuelling of plasmas by shallow frozen pellets with simultaneous mitigation of edge localised modes (ELM) by external magnetic perturbation is demonstrated on the MAST tokamak. Post-pellet particle loss is dominated by ELMs and inter-ELM gas fuelling. It is shown that the size of post-pellet ELMs can be controlled by external magnetic perturbations. Post-pellet ELMs remove particles from the large part of pellet deposition zone including the area with positive density gradient. The mechanism explaining this peculiarity of particle loss is suggested.
Turbulent electron transport in edge pedestal by electron temperature gradient turbulence
Singh, R.; Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 ; Jhang, Hogun; Diamond, P. H.; CMTFO and CASS, University of California, San Diego 92093-0424, California
2013-11-15
We present a model for turbulent electron thermal transport at the edge pedestal in high (H)-mode plasmas based on electron temperature gradient (ETG) turbulence. A quasi-linear analysis of electrostatic toroidal ETG modes shows that both turbulent electron thermal diffusivity and hyper-resistivity exhibits the Ohkawa scaling in which the radial correlation length of turbulence becomes the order of electron skin depth. Combination of the Ohkawa scales and the plasma current dependence results in a novel confinement scaling inside the pedestal region. It is also shown that ETG turbulence induces a thermoelectric pinch, which may accelerate the density pedestal formation.
Measurement of quasiparticle transport in aluminum films using tungsten transition-edge sensors
Yen, J. J. Shank, B.; Cabrera, B.; Moffatt, R.; Redl, P.; Young, B. A.; Tortorici, E. C.; Brink, P. L.; Cherry, M.; Tomada, A.; Kreikebaum, J. M.
2014-10-20
We report on experimental studies of phonon sensors which utilize quasiparticle diffusion in thin aluminum films connected to tungsten transition-edge-sensors (TESs) operated at 35 mK. We show that basic TES physics and a simple physical model of the overlap region between the W and Al films in our devices enables us to accurately reproduce the experimentally observed pulse shapes from x-rays absorbed in the Al films. We further estimate quasiparticle loss in Al films using a simple diffusion equation approach. These studies allow the design of phonon sensors with improved performance.
Ji, Y., E-mail: yji@spaceweather.ac.cn [State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China); College of Earth Science, University of Chinese Academy of Sciences, Beijing 100049 (China); Shen, C. [State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China)] [State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China)
2014-03-15
With consideration of magnetic field line curvature (FLC) pitch angle scattering and charge exchange reactions, the O{sup +} (>300?keV) in the inner magnetosphere loss rates are investigated by using an eigenfunction analysis. The FLC scattering provides a mechanism for the ring current O{sup +} to enter the loss cone and influence the loss rates caused by charge exchange reactions. Assuming that the pitch angle change is small for each scattering event, the diffusion equation including a charge exchange term is constructed and solved; the eigenvalues of the equation are identified. The resultant loss rates of O{sup +} are approximately equal to the linear superposition of the loss rate without considering the charge exchange reactions and the loss rate associated with charge exchange reactions alone. The loss time is consistent with the observations from the early recovery phases of magnetic storms.