National Library of Energy BETA

Sample records for trailing edge curvatures

  1. Trailing edge modifications for flatback airfoils.

    SciTech Connect (OSTI)

    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.

  2. Persistent source influences on the trailing edge of a groundwater...

    Office of Scientific and Technical Information (OSTI)

    Persistent source influences on the trailing edge of a groundwater plume, and natural attenuation timeframes: The F-Area Savannah River Site Citation Details In-Document Search ...

  3. Partially turbulated trailing edge cooling passages for gas turbine nozzles

    DOE Patents [OSTI]

    Thatcher, Jonathan Carl (Schenectady, NY); Burdgick, Steven Sebastian (Schenectady, NY)

    2001-01-01

    A plurality of passages are spaced one from the other along the length of a trailing edge of a nozzle vane in a gas turbine. The passages lie in communication with a cavity in the vane for flowing cooling air from the cavity through the passages through the tip of the trailing edge into the hot gas path. Each passage is partially turbulated and includes ribs in an aft portion thereof to provide enhanced cooling effects adjacent the tip of the trailing edge. The major portions of the passages are smooth bore. By this arrangement, reduced temperature gradients across the trailing edge metal are provided. Additionally, the inlets to each of the passages have a restriction whereby a reduced magnitude of compressor bleed discharge air is utilized for trailing edge cooling purposes.

  4. Survey of techniques for reduction of wind turbine blade trailing edge noise.

    SciTech Connect (OSTI)

    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.

  5. Atmospheric testing of wind turbine trailing edge aerodynamic brakes

    SciTech Connect (OSTI)

    Miller, L.S.; Migliore, P.G.; Quandt, G.A.

    1997-12-31

    An experimental investigation was conducted using an instrumented horizontal-axis wind turbine that incorporated variable span trailing-edge aerodynamic brakes. A primary goal was to directly compare study results with (infinite-span) wind tunnel data and to provide information on how to account for device span effects during turbine design or analysis. Comprehensive measurements were utilized to define effective changes in the aerodynamic coefficients, as a function of angle of attack and control deflection, for three device spans and configurations. Differences in the lift and drag behavior are most pronounced near stall and for device spans of less than 15%. Drag performance is affected only minimally (<70%) for 15% or larger span devices. Interestingly, aerodynamic controls with characteristic vents or openings appear most affected by span reductions and three-dimensional flow.

  6. Trailing edge cooling using angled impingement on surface enhanced with cast chevron arrangements

    DOE Patents [OSTI]

    Lee, Ching-Pang; Heneveld, Benjamin E.; Brown, Glenn E.; Klinger, Jill

    2015-05-26

    A gas turbine engine component, including: a pressure side (12) having an interior surface (34); a suction side (14) having an interior surface (36); a trailing edge portion (30); and a plurality of suction side and pressure side impingement orifices (24) disposed in the trailing edge portion (30). Each suction side impingement orifice is configured to direct an impingement jet (48) at an acute angle (52) onto a target area (60) that encompasses a tip (140) of a chevron (122) within a chevron arrangement (120) formed in the suction side interior surface. Each pressure side impingement orifice is configured to direct an impingement jet at an acute angle onto an elongated target area that encompasses a tip of a chevron within a chevron arrangement formed in the pressure side interior surface.

  7. Trailing edge devices to improve performance and increase lifetime of wind-electric water pumping systems

    SciTech Connect (OSTI)

    Vick, B.D.; Clark, R.N.

    1996-12-31

    Trailing edge flaps were applied to the blades of a 10 kW wind turbine used for water pumping to try to improve the performance and decrease the structural fatigue on the wind turbine. Most small wind turbines (10 kW and below) use furling (rotor turns out of wind similar to a mechanical windmill) to protect the wind turbine from overspeed during high winds. Some small wind turbines, however, do not furl soon enough to keep the wind turbine from being off line part of the time in moderately high wind speeds (10 - 16 m/s). As a result, the load is disconnected and no water is pumped at moderately high wind speeds. When the turbine is offline, the frequency increases rapidly often causing excessive vibration of the wind turbine and tower components. The furling wind speed could possibly be decreased by increasing the offset between the tower centerline and the rotor centerline, but would be a major and potentially expensive retrofit. Trailing edge flaps (TEF) were used as a quick inexpensive method to try to reduce the furling wind speed and increase the on time by reducing the rotor RPM. One TEF configuration improved the water pumping performance at moderately high wind speeds, but degraded the pumping performance at low wind speeds which resulted in little change in daily water volume. The other TEF configuration differed very little from the no flap configuration. Both TEF configurations however, reduced the rotor RPM in high wind conditions. The TEF, did not reduce the rotor RPM by lowering the furling wind speed as hoped, but apparently did so by increasing the drag which also reduced the volume of water pumped at the lower wind speeds. 6 refs., 9 figs.

  8. Trails List

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Allowed: hiking, walking, running, biking, horseback riding, photography Bicycles must stay on established trails. Bicycles yield to pedestrians and horses. Anniversary Trail...

  9. Trails List

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    List Trails List Trail-specific access information and rules. It is your responsibility to understand the rules of a particular trail. Contact Environmental Communication & Public Involvement P.O. Box 1663 MS M996 Los Alamos, NM 87545 (505) 667-0216 Email A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z Ancho Canyon Trail Closed Ancho Springs Trail Access: Open to the public Length: 1.78 miles Elevation change: 1027 feet Connecting trails:

  10. Sandia Energy - Experiment for Improved Modeling of Trailing...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Experiment for Improved Modeling of Trailing-Edge Shedding Noise Home Renewable Energy Energy Water Power Partnership News News & Events Computational Modeling & Simulation...

  11. Trails Working Group

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and Recreational Trails Use at Los Alamos National Laboratory, Los Alamos, New Mexico: Education and Mitigation An Assessment of the Impact of Social Trails Use on Cultural...

  12. Trails Working Group

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Working Group Trails Working Group Our mission is to inventory, map, and prepare historical reports on the many trails used at LANL. Contact Environmental Communication & Public Involvement P.O. Box 1663 MS M996 Los Alamos, NM 87545 (505) 667-0216 Email The LANL Trails Working Group inventories, maps, and prepares historical reports on the many trails used at LANL. Some of these trails are ancient pueblo footpaths that continue to be used for recreational hiking today. Some serve as quiet

  13. Taking Care of our Trails

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Trails Taking Care of our Trails Continued access and use of Los Alamos National Laboratory trails is contingent upon being good stewards of these federal lands. Contact Environmental Communication & Public Involvement P.O. Box 1663 MS M996 Los Alamos, NM 87545 (505) 667-0216 Email View in Google Maps Most Laboratory hiking trails reopened Due to a significant drop in the number of bear sightings and encounters the Laboratory has reopened most trails on its property. Several trails on

  14. Taking Care of our Trails

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of weather conditions, hazards, and wildlife. Please leave no trace and pack out your trash. Trail Monitoring LANL trails in the White Rock area (TAs 7071) are actively...

  15. DRBE comet trails

    SciTech Connect (OSTI)

    Arendt, Richard G.

    2014-12-01

    Re-examination of the Cosmic Background Explorer Diffuse Infrared Background Experiment (DIRBE) data reveals the thermal emission of several comet dust trails. The dust trails of 1P/Halley, 169P/NEAT, and 3200 Phaethon have not been previously reported. The known trails of 2P/Encke and 73P/Schwassmann–Wachmann 3 are also seen. The dust trails have 12 and 25 μm surface brightnesses of <0.1 and <0.15 MJy sr{sup −1}, respectively, which is <1% of the zodiacal light intensity. The trails are very difficult to see in any single daily image of the sky, but are evident as rapidly moving linear features in movies of the DIRBE data. Some trails are clearest when crossing through the orbital plane of the parent comet, but others are best seen at high ecliptic latitudes as the Earth passes over or under the dust trail. All these comets have known associations with meteor showers. This re-examination also reveals 1 additional comet and 13 additional asteroids that had not previously been recognized in the DIRBE data.

  16. Kinetic information from detonation front curvature

    SciTech Connect (OSTI)

    Souers, P. C., LLNL

    1998-06-15

    The time constants for time-dependent modeling may be estimated from reaction zone lengths, which are obtained from two sources One is detonation front curvature, where the edge lag is close to being a direct measure The other is the Size Effect, where the detonation velocity decreases with decreasing radius as energy is lost to the cylinder edge A simple theory that interlocks the two effects is given A differential equation for energy flow in the front is used, the front is described by quadratic and sixth-power radius terms The quadratic curvature comes from a constant power source of energy moving sideways to the walls Near the walls, the this energy rises to the total energy of detonation and produces the sixth-power term The presence of defects acting on a short reaction zone can eliminate the quadratic part while leaving the wall portion of the cuvature A collection of TNT data shows that the reaction zone increases with both the radius and the void fraction

  17. National Trail Biodiesel | Open Energy Information

    Open Energy Info (EERE)

    Trail Biodiesel Jump to: navigation, search Name: National Trail Biodiesel Place: Newton, Illinois Zip: 62448 Product: Owner of a planned 30m gallon per year biodiesel plant in...

  18. TWP Island Cloud Trail Studies

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    These island cloud trails have been observed from both the islands of Nauru and Manus, Papua New Guinea. Figure 2 shows an island cloud at Manus observed from MTI and from the ...

  19. Persistent source influences on the trailing edge of a groundwater...

    Office of Scientific and Technical Information (OSTI)

    Sponsoring Org: USDOE Office of Science (SC) Country of Publication: United States Language: English Subject: 54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES Word Cloud More Like This ...

  20. Wind turbine trailing-edge aerodynamic brake design

    SciTech Connect (OSTI)

    Quandt, G.

    1996-01-01

    This report describes the design of a centrifugally actuated aerodynamic-overspeed device for a horizontal-axis wind turbine. The device will meet the following criteria; (1) It will be effective for airfoil angles of attack 0{degrees} to 45{degrees}. (2) It will be stowed inside the blade profile prior to deployment. (3) It will be capable of offsetting the positive torque produced by the overall blade. (4) Hinge moments will be minimized to lower actuator loads and cost. (5) It will be evaluated as a potential power modulating active rotor-control system. A literature review of aerodynamic braking devices was conducted. Information from the literature review was used to conceptualize the most effective devices for subsequent testing and design. Wind-tunnel test data for several braking devices are presented in this report. Using the data for the most promising configuration, a preliminary design was developed for a MICON 65/13 wind turbine with Phoenix 7.9-m rotor blades.

  1. Edge Bioinformatics

    SciTech Connect (OSTI)

    Lo, Chien-Chi

    2015-08-03

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

  2. Edge Bioinformatics

    Energy Science and Technology Software Center (OSTI)

    2015-08-03

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

  3. Oregon Trail Mushrooms Industrial Low Temperature Geothermal...

    Open Energy Info (EERE)

    Mushrooms Industrial Low Temperature Geothermal Facility Jump to: navigation, search Name Oregon Trail Mushrooms Industrial Low Temperature Geothermal Facility Facility Oregon...

  4. Beam Trail Tracking at Fermilab

    SciTech Connect (OSTI)

    Nicklaus, Dennis J.; Carmichael, Linden Ralph; Neswold, Richard; Yuan, Zongwei

    2015-01-01

    We present a system for acquiring and sorting data from select devices depending on the destination of each particular beam pulse in the Fermilab accelerator chain. The 15 Hz beam that begins in the Fermilab ion source can be directed to a variety of additional accelerators, beam lines, beam dumps, and experiments. We have implemented a data acquisition system that senses the destination of each pulse and reads the appropriate beam intensity devices so that profiles of the beam can be stored and analysed for each type of beam trail. We envision utilizing this data long term to identify trends in the performance of the accelerators

  5. Mirror with thermally controlled radius of curvature

    DOE Patents [OSTI]

    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.

  6. Radius of curvature controlled mirror

    DOE Patents [OSTI]

    Neil, George R.; Rathke, John Wickham; Schultheiss, Thomas John; Shinn, Michelle D.; Dillon-Townes, Lawrence A.

    2006-01-17

    A controlled radius of curvature mirror assembly comprising: a distortable mirror having a reflective surface and a rear surface; and in descending order from the rear surface; a counter-distortion plate; a flow diverter having a flow diverter aperture at the center thereof; a flow return plate having a flow return aperture at the center thereof; a thermal isolation plate having a thermal isolation plate aperture at the center thereof and a flexible heater having a rear surface and a flexible heater aperture at the center thereof; a double walled tube defining a coolant feed chamber and a coolant return chamber; said coolant feed chamber extending to and through the flow diverter aperture and terminating at the counter-distortion plate and the coolant return chamber extending to and through the thermal isolation backplate and terminating at the flow diverter; and a coolant feed and a coolant return exit at the rear of said flexible heater.

  7. Integrating 3D seismic curvature and curvature gradient attributes for fracture characterization: Methodologies and interpretational implications

    SciTech Connect (OSTI)

    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.

  8. Unified EDGE

    Energy Science and Technology Software Center (OSTI)

    2007-06-18

    UEDGE is an interactive suite of physics packages using the Python or BASIS scripting systems. The plasma is described by time-dependent 2D plasma fluid equations that include equations for density, velocity, ion temperature, electron temperature, electrostatic potential, and gas density in the edge region of a magnetic fusion energy confinement device. Slab, cylindrical, and toroidal geometries are allowed, and closed and open magnetic field-line regions are included. Classical transport is assumed along magnetic field lines,more » and anomalous transport is assumed across field lines. Multi-charge state impurities can be included with the corresponding line-radiation energy loss. Although UEDGE is written in Fortran, for efficient execution and analysis of results, it utilizes either Python or BASIS scripting shells. Python is easily available for many platforms (http://www.Python.org/). The features and availability of BASIS are described in “Basis Manual Set” by P.F. Dubois, Z.C. Motteler, et al., Lawrence Livermore National Laboratory report UCRL-MA-1 18541, June, 2002 and http://basis.llnl.gov. BASIS has been reviewed and released by LLNL for unlimited distribution. The Python version utilizes PYBASIS scripts developed by D.P. Grote, LLNL. The Python version also uses MPPL code and MAC Perl script, available from the public-domain BASIS source above. The Forthon version of UEDGE uses the same source files, but utilizes Forthon to produce a Python-compatible source. Forthon has been developed by D.P. Grote at LBL (see http://hifweb.lbl.gov/Forthon/ and Grote et al. in the references below), and it is freely available. The graphics can be performed by any package importable to Python, such as PYGIST.« less

  9. Curvature constraints from the causal entropic principle

    SciTech Connect (OSTI)

    Bozek, Brandon; Albrecht, Andreas; Phillips, Daniel

    2009-07-15

    Current cosmological observations indicate a preference for a cosmological constant that is drastically smaller than what can be explained by conventional particle physics. The causal entropic principle (Bousso et al.) provides an alternative approach to anthropic attempts to predict our observed value of the cosmological constant by calculating the entropy created within a causal diamond. We have extended this work to use the causal entropic principle to predict the preferred curvature within the 'multiverse'. We have found that values larger than {rho}{sub k}=40{rho}{sub m} are disfavored by more than 99.99% peak value at {rho}{sub {lambda}}=7.9x10{sup -123} and {rho}{sub k}=4.3{rho}{sub m} for open universes. For universes that allow only positive curvature or both positive and negative curvature, we find a correlation between curvature and dark energy that leads to an extended region of preferred values. Our universe is found to be disfavored to an extent depending on the priors on curvature. We also provide a comparison to previous anthropic constraints on open universes and discuss future directions for this work.

  10. LA-UR-14-22379 Trails Management at LANL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    areas not open for recreational use. In addition, some trails are open to the public LA-UR-14-22379 while others are only open to LANL badge holders; thus, trail use and access...

  11. On the edge energy of lipid membranes and the thermodynamic stability of pores

    SciTech Connect (OSTI)

    Pera, H.; Kleijn, J. M.; Leermakers, F. A. M.

    2015-01-21

    To perform its barrier function, the lipid bilayer membrane requires a robust resistance against pore formation. Using a self-consistent field (SCF) theory and a molecularly detailed model for membranes composed of charged or zwitterionic lipids, it is possible to predict structural, mechanical, and thermodynamical parameters for relevant lipid bilayer membranes. We argue that the edge energy in membranes is a function of the spontaneous lipid monolayer curvature, the mean bending modulus, and the membrane thickness. An analytical Helfrich-like model suggests that most bilayers should have a positive edge energy. This means that there is a natural resistance against pore formation. Edge energies evaluated explicitly in a two-gradient SCF model are consistent with this. Remarkably, the edge energy can become negative for phosphatidylglycerol (e.g., dioleoylphosphoglycerol) bilayers at a sufficiently low ionic strength. Such bilayers become unstable against the formation of pores or the formation of lipid disks. In the weakly curved limit, we study the curvature dependence of the edge energy and evaluate the preferred edge curvature and the edge bending modulus. The latter is always positive, and the former increases with increasing ionic strength. These results point to a small window of ionic strengths for which stable pores can form as too low ionic strengths give rise to lipid disks. Higher order curvature terms are necessary to accurately predict relevant pore sizes in bilayers. The electric double layer overlap across a small pore widens the window of ionic strengths for which pores are stable.

  12. Tube curvature measuring probe and method

    DOE Patents [OSTI]

    Sokol, George J.

    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.

  13. LA-UR-14-22379 Trails Management at LANL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    4-22379 Trails Management at LANL New informational kiosk and gates installed at the Potrillo Canyon Loop trailhead in TA-71 near Pajarito Acres. Background Recreational trails use at Los Alamos National Laboratory (LANL) has been considered one of the benefits of working and living in Los Alamos County (LAC). However, there was never an explicit Department of Energy (DOE)/National Nuclear Security Administration (NNSA) or Los Alamos National Security, LLC policy or mechanism to balance trails

  14. LANL closes road, trails for safety reasons; flooding and erosion...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    closed for 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...

  15. Microsoft Word - Trails FONSI for LANL Library.doc

    National Nuclear Security Administration (NNSA)

    the Los Alamos National Laboratory Proposed Trails Management Program, Los Alamos, New Mexico U. S. Department of Energy National Nuclear Security Administration Los Alamos Site...

  16. LPG odorization with an audit trail

    SciTech Connect (OSTI)

    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.

  17. Timing discriminator using leading-edge extrapolation

    DOE Patents [OSTI]

    Gottschalk, Bernard

    1983-01-01

    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. 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.

  18. Timing discriminator using leading-edge extrapolation

    DOE Patents [OSTI]

    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.

  19. BICEP2, the curvature perturbation and supersymmetry

    SciTech Connect (OSTI)

    Lyth, David H.

    2014-11-01

    The tensor fraction r?0.16 found by BICEP2 corresponds to a Hubble parameter H?1.0נ10{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.

  20. ClearEdge Power

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    From This To This To This ClearEdge5 - Delivering Smart Energy Today Combined heat and power 5kWh distributed power system CE5 converts natural gas into power and heat without ...

  1. Observations of Edge Turbulence

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    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...

  2. Russel Edge | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Russel Edge About Us Russel Edge Team Leader, Uranium Mine Team Russel Edge became an LM staff member on November 2, 2014, as a Business Management Specialist in the Westminster, ...

  3. 16 USC 1246 - Administration and Development of National Trails...

    Open Energy Info (EERE)

    1246 - Administration and Development of National Trails System Jump to: navigation, search OpenEI Reference LibraryAdd to library Legal Document- StatuteStatute: 16 USC 1246 -...

  4. Oregon Trail El Cons Coop, Inc | Open Energy Information

    Open Energy Info (EERE)

    El Cons Coop, Inc Jump to: navigation, search Name: Oregon Trail El Cons Coop, Inc Place: Oregon Phone Number: Baker County: 541-523-3616; Harney: 541-573-2666; Grant:...

  5. Trails and Dead Bodies: Directly Characterizing Extrasolar Planets...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    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...

  6. Airfoil

    DOE Patents [OSTI]

    Ristau, Neil; Siden, Gunnar Leif

    2015-07-21

    An airfoil includes a leading edge, a trailing edge downstream from the leading edge, a pressure surface between the leading and trailing edges, and a suction surface between the leading and trailing edges and opposite the pressure surface. A first convex section on the suction surface decreases in curvature downstream from the leading edge, and a throat on the suction surface is downstream from the first convex section. A second convex section is on the suction surface downstream from the throat, and a first convex segment of the second convex section increases in curvature.

  7. Pressure-Responsive Curvature Change of a "Rigid" Geodesic Ligand...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Pressure-Responsive Curvature Change of a "Rigid" Geodesic Ligand in a (3,24)-Connected Mesoporous Metal-Organic Framework Previous Next List Daqiang Yuan, Dan Zhao, and Hong-Cai ...

  8. Layered devices having surface curvature and method of constructing same

    DOE Patents [OSTI]

    Woodbury, Richard C.; Perkins, Raymond T.; Thorne, James M.

    1989-01-01

    A method of treating a substrate having first and second sides with corresponding oppositely facing first and second surfaces, to produce curvature in the first surface. The method includes the steps of removing material, according to a predetermined pattern, from the second side of the substrate, and applying a stress-producing film of material to at least one surface of the substrate to thereby cause the substrate to bend to produce the desired curvature in the first surface.

  9. Topology of codimension-one foliations of nonnegative curvature

    SciTech Connect (OSTI)

    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.

  10. Trails Management at LANL - A Presentation to the Los Alamos County Parks and Recreation Board

    SciTech Connect (OSTI)

    Pava, Daniel Seth

    2015-05-12

    Los Alamos National Laboratorys (LANL) trail management program goals include reduce risk of damage and injury to property, human life, and health, and sensitive natural and cultural resources from social trail use at LANL, facilitate the establishment of a safe viable network of linked trails, maintain security of LANL operations, and many more, respect the wishes of local Pueblos, adapt trail use to changing conditions in a responsive manner, and maintain the recreational functionality of the DOE lands. There are approximately 30 miles of LANL trails. Some are open to the public and allow bicycles, horses, hikers, and runners. Know the rules of the trails to stay safe.

  11. Surface Curvatures and Diffraction Profiles of Sagittaly Bent Laue Crystals

    SciTech Connect (OSTI)

    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.

  12. Studies of the effects of curvature on dilution jet mixing

    SciTech Connect (OSTI)

    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.

  13. 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...

  14. EDG Fuels | Open Energy Information

    Open Energy Info (EERE)

    search Name: EDG Fuels Place: Silver City, Arizona Zip: 88062 Product: Arizona-based biodiesel producer. References: EDG Fuels1 This article is a stub. You can help OpenEI...

  15. DNA Origami with Complex Curvatures in Three-Dimensional Space

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    DNA Origami with Complex Curvatures in Three-Dimensional Space Authors: Han, D., Pal, S., Nangreave, J., Deng, Z., Liu, Y., and Yan, H. Title: DNA Origami with Complex Curvatures in Three-Dimensional Space Source: Science Year: 2011 Volume: 332 Pages: 342-346 ABSTRACT: We present a strategy to design and construct self-assembling DNA nanostructures that define intricate curved surfaces in three-dimensional (3D) space using the DNA origami folding technique. Double-helical DNA is bent to follow

  16. Clean Edge Inc | Open Energy Information

    Open Energy Info (EERE)

    Edge Inc Jump to: navigation, search Logo: Clean Edge Inc Name: Clean Edge Inc Place: Portland, Oregon Zip: 97213 Region: Pacific Northwest Area Website: www.cleanedge.com...

  17. Fiscal Year 2013 Trails Management Program Mitigation Action Plan Annual Report, October 2013

    SciTech Connect (OSTI)

    Pava, Daniel S.

    2015-03-25

    This Trails Management Program Mitigation Action Plan Annual Report (Trails MAPAR) has been prepared for the Department of Energy (DOE)/National Nuclear Security Administration (NNSA) as part of implementing the 2003 Final Environmental Assessment for the Proposed Los Alamos National Laboratory Trails Management Program (DOE 2003). The Trails Mitigation Action Plan (MAP) is now a part of the Site-Wide Environmental Impact Statement for the Continued Operation of Los Alamos National Laboratory (DOE/EIS 0380) Mitigation Action Plan (2008 SWEIS MAP) (DOE 2008). The MAP provides guidance for the continued implementation of the Trails Management Program at Los Alamos National Laboratory (LANL) and integration of future mitigation actions into the 2008 SWEIS MAP to decrease impacts associated with recreational trails use at LANL. This eighth MAPAR includes a summary of Trails Management Program activities and actions during Fiscal Year (FY) 2013, from October 2012 through September 2013.

  18. Edge remap for solids

    SciTech Connect (OSTI)

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

    2013-12-01

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

  19. Curvature effects on carbon nanomaterials: Exohedral versus endhohedral supercapacitors

    SciTech Connect (OSTI)

    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.

  20. Curvature effects in carbon nanomaterials: Exohedral versus endohedral supercapacitors

    SciTech Connect (OSTI)

    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.

  1. CURVATURE-DRIFT INSTABILITY FAILS TO GENERATE PULSAR RADIO EMISSION

    SciTech Connect (OSTI)

    Kaganovich, Alexander; Lyubarsky, Yuri

    2010-10-01

    The curvature-drift instability has long been considered as a viable mechanism for pulsar radio emission. We reconsidered this mechanism by finding an explicit solution describing the propagation of short electromagnetic waves in a plasma flow along curved magnetic field lines. We show that even though the waves could be amplified, the amplification factor remains very close to unity; therefore, this mechanism is unable to generate high brightness temperature emission from initial weak fluctuations.

  2. Method of and apparatus for collecting solar radiation utilizing variable curvature cylindrical reflectors

    DOE Patents [OSTI]

    Treytl, William J.; Slemmons, Arthur J.; Andeen, Gerry B.

    1979-01-01

    A heliostat apparatus includes a frame which is rotatable about an axis which is parallel to the aperture plane of an elongate receiver. A plurality of flat flexible mirror elements are mounted to the frame between several parallel, uniformly spaced resilient beams which are pivotally connected at their ends to the frame. Channels are mounted to the sides of the beams for supporting the edges of the mirror elements. Each of the beams has a longitudinally varying configuration designed to bow into predetermined, generally circular curvatures of varying radii when the center of the beam is deflected relative to the pivotally connected ends of the beams. All of the parallel resilient beams are simultaneously deflected by a cam shaft assembly extending through openings in the centers of the beams, whereby the mirror elements together form an upwardly concave, cylindrical reflecting surface. The heliostat is rotated about its axis to track the apparent diurnal movement of the sun, while the reflecting surface is substantially simultaneously bowed into a cylindrical trough having a radius adapted to focus incident light at the plane of the receiver aperture.

  3. Curvature effect on tearing modes in presence of neoclassical friction

    SciTech Connect (OSTI)

    Maget, Patrick; Mellet, Nicolas; Meshcheriakov, Dmytro; Garbet, Xavier; Lütjens, Hinrich

    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.

  4. Direct and alignment-insensitive measurement of cantilever curvature

    SciTech Connect (OSTI)

    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.

  5. Statistical anisotropy of the curvature perturbation from vector field perturbations

    SciTech Connect (OSTI)

    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.

  6. Curvature and geometric modules of noncommutative spheres and tori

    SciTech Connect (OSTI)

    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.

  7. Closeness to spheres of hypersurfaces with normal curvature bounded below

    SciTech Connect (OSTI)

    Borisenko, A A; Drach, K D

    2013-11-30

    For aRiemannian manifold M{sup n+1} and acompact domain ??M{sup n+1} bounded by ahypersurface ?? with normal curvature bounded below, estimates are obtained in terms of the distance from O to ?? for the angle between the geodesic line joining afixed interior point O in ? to apoint on ?? and the outward normal to the surface. Estimates for the width of aspherical shell containing such ahypersurface are also presented. Bibliography: 9 titles.

  8. Edge equilibrium code for tokamaks

    SciTech Connect (OSTI)

    Li, Xujing; Drozdov, Vladimir V.

    2014-01-15

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

  9. EDGE Energy LLC | Open Energy Information

    Open Energy Info (EERE)

    EDGE Energy LLC Jump to: navigation, search Name: EDGE Energy LLC Place: Phoenix, Arizona Zip: 85018 Sector: Solar Product: Arizona-based solar developer focused on building...

  10. Region and edge-adaptive sampling and boundary completion for segmentation

    SciTech Connect (OSTI)

    Dillard, Scott E; Prasad, Lakshman; Grazzini, Jacopo A

    2010-01-01

    Edge detection produces a set of points that are likely to lie on discontinuities between objects within an image. We consider faces of the Gabriel graph of these points, a sub-graph of the Delaunay triangulation. Features are extracted by merging these faces using size, shape and color cues. We measure regional properties of faces using a novel shape-dependant sampling method that overcomes undesirable sampling bias of the Delaunay triangles. Instead, sampling is biased so as to smooth regional statistics within the detected object boundaries, and this smoothing adapts to local geometric features of the shape such as curvature, thickness and straightness.

  11. EDGE

    Energy Science and Technology Software Center (OSTI)

    002099IBMPC00 MM-Estimator and Adjusted Super Smoother based Simultaneous Prediction Confedenc http://nature.berkeley.edu/vulpelab/loguinov/

  12. Dual curvature acoustically damped concentrating collector. Final technical report

    SciTech Connect (OSTI)

    Smith, G.A.; Rausch, R.A.

    1980-05-01

    A development program was conducted to investigate the design and performance parameters of a novel, dual curvature, concentrating solar collector. The reflector of the solar collector is achieved with a stretched-film reflective surface that approximates a hyperbolic paraboloid and is capable of line-focusing at concentration ratios ranging from 10 to 20X. A prototype collector was designed based on analytical and experimental component trade-off activities as well as economic analyses of solar thermal heating and cooling systems incorporating this type of collector. A prototype collector incorporating six 0.66 x 1.22 m (2 x 4 ft) was fabricated and subjected to a limited thermal efficiency test program. A peak efficiency of 36% at 121/sup 0/C (250/sup 0/F) was achieved based upon the gross aperture area. Commercialization activities were conducted, including estimated production costs of $134.44/m/sup 2/ ($12.49/ft/sup 2/) for the collector assembly (including a local suntracker and controls) and $24.33/m/sup 2/ ($2.26/ft/sup 2/) for the reflector subassembly.

  13. Etching Of Semiconductor Wafer Edges

    DOE Patents [OSTI]

    Kardauskas, Michael J. (Billerica, MA); Piwczyk, Bernhard P. (Dunbarton, NH)

    2003-12-09

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

  14. Glenn Seaborg Trail | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    ... A bench in the woods Benches along the midpoint of the trail provide a tranquil spot to rest and enjoy the forest. Bridge The southern bridge links the eastern and western slopes ...

  15. Emerging Edge Capital EEC | Open Energy Information

    Open Energy Info (EERE)

    Edge Capital EEC Jump to: navigation, search Name: Emerging Edge Capital (EEC) Place: London, United Kingdom Zip: SW1Y 4RS Sector: Renewable Energy Product: London-based company...

  16. PICK-UP ION DISTRIBUTIONS AND THEIR INFLUENCE ON ENERGETIC NEUTRAL ATOM SPECTRAL CURVATURE

    SciTech Connect (OSTI)

    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.

  17. Topology of codimension-one foliations of nonnegative curvature.II

    SciTech Connect (OSTI)

    Bolotov, D V

    2014-10-31

    We prove that a3-connected closed manifold M of dimension n?5 does not admit acodimension-one C{sup 2}-foliation of nonnegative curvature. In particular, this gives acomplete answer to aquestion 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 manifoldM with leaves having finitely generated fundamental group, and show that such afoliation is flat if and only if M is aK(?,1)-manifold. Bibliography: 13 titles.

  18. Densified edge seals for fuel cell components

    DOE Patents [OSTI]

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

    1982-01-01

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

  19. K-edge densitometer (KED)

    SciTech Connect (OSTI)

    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.

  20. Estimation of the curvature of an interface from a digital 2D image

    SciTech Connect (OSTI)

    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.

  1. All bulk and boundary unitary cubic curvature theories in three dimensions

    SciTech Connect (OSTI)

    Guellue, Ibrahim; Sisman, Tahsin Cagri; Tekin, Bayram

    2011-01-15

    We construct all the bulk and boundary unitary cubic curvature parity invariant gravity theories in three dimensions in (anti)-de Sitter spaces. For bulk unitarity, our construction is based on the principle that the free theory of the cubic curvature theory reduces to one of the three known unitary theories which are the cosmological Einstein-Hilbert theory, the quadratic theory of the scalar curvature, or the new massive gravity (NMG). Bulk and boundary unitarity in NMG is in conflict; therefore, cubic theories that are unitary both in the bulk and on the boundary have free theories that reduce to the other two alternatives. We also study the unitarity of the Born-Infeld extensions of NMG to all orders in curvature.

  2. Synchro-curvature radiation of charged particles in the strong curved magnetic fields

    SciTech Connect (OSTI)

    Kelner, S. R.; Prosekin, A. Yu.; Aharonian, F. A. E-mail: Anton.Prosekin@mpi-hd.mpg.de

    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.

  3. Interferon-α and cyclooxygenase-2 inhibitor cooperatively mediates TRAIL-induced apoptosis in hepatocellular carcinoma

    SciTech Connect (OSTI)

    Zuo, Chaohui; Qiu, Xiaoxin; Liu, Nianli; Yang, Darong; Xia, Man; Liu, Jingshi; Wang, Xiaohong; and others

    2015-05-01

    Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide. Interferon-alpha (IFN-α) has recently been recognized to harbor therapeutic potential in the prevention and treatment of HCC, but it remains controversial as to whether IFN-α exerts direct cytotoxicity against HCC. Cyclooxygenase-2 (COX-2) is overexpressed in HCC and is considered to play a role in hepatocarcinogenesis. Therefore, we aimed to elucidate the combined effect of a COX-2 inhibitor, celecoxib, and IFN-α on in vitro growth suppression of HCC using the hepatoma cell line HLCZ01 and the in vivo nude mouse xenotransplantation model using HLCZ01 cells. Treatment with celecoxib and IFN-α synergistically inhibited cell proliferation in a dose- and time-dependent manner. Apoptosis was identified by 4',6-diamidino-2-phenylindole dihydrochloride and fluorescent staining. IFN-α upregulated the expression of TRAIL, while celecoxib increased the expression of TRAIL receptors. The combined regimen with celecoxib and IFN-α reduced the growth of xenotransplanted HCCs in nude mice. The regulation of IFN-α- and COX-2 inhibitor-induced cell death is impaired in a subset of TRAIL-resistant cells. The molecular mechanisms of HCC cells resistant to TRAIL-induced apoptosis were explored using molecular biological and immunological methods. Interferon-α and the COX-2 inhibitor celecoxib synergistically increased TRAIL-induced apoptosis in hepatocellular carcinoma. These data suggest that IFN-α and celecoxib may offer a novel role with important implications in designing new therapeutics for TRAIL-resistant tumors. - Highlights: ●The cytotoxic effect of TRAIL on a developed HCC HLCZ01 cells infected with HBV. ●IFN-α and celecoxib induced apoptosis in HLCZ01 cells infected with HBV. ●The combined regime reduced the growth of xenotransplanted HCCs in nude mice model.

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

    SciTech Connect (OSTI)

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

    2015-02-15

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

  5. Leading Edge Technologies Inc | Open Energy Information

    Open Energy Info (EERE)

    Edge Technologies Inc Place: Lakeland, Florida Product: Profitable manufacturer of lithium ion batteries for consumer electronics makers that merged with Skylab Technologies...

  6. Visible imaging of edge turbulence in NSTX

    SciTech Connect (OSTI)

    S. Zweben; R. Maqueda; K. Hill; D. Johnson; et al

    2000-06-13

    Edge plasma turbulence in tokamaks and stellarators is believed to cause the radical heat and particle flux across the separatrix and into the scrape-off-layers of these devices. This paper describes initial measurements of 2-D space-time structure of the edge density turbulence made using a visible imaging diagnostic in the National Spherical Torus Experiment (NSTX). The structure of the edge turbulence is most clearly visible using a method of gas puff imaging to locally illuminate the edge density turbulence.

  7. Los Alamos science sleuth on the trail of a martian mystery

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Trail of a martian mystery Los Alamos science sleuth on the trail of a martian mystery When it comes to examining the surface of rocks on Mars with a high-powered laser, five is a magic number for LANL postdoctoral researcher Nina Lanza. March 19, 2013 This dual image of a Martian rock taken by the ChemCam instrument aboard the Curiosity rover shows a rock at the "Rocknest" area on Mars before it was interrogated with ChemCam's high-powered laser (left) and after interrogation by 600

  8. LANL closes road, trails for safety reasons; flooding and erosion control

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    work under way Road, trails closed for 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 flooding. July 8, 2011 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma physics and new

  9. Curvature of the freeze-out line in heavy ion collisions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bazavov, A.; Ding, H. -T.; Hegde, P.; Kaczmarek, O.; Karsch, F.; Laermann, E.; Mukherjee, Swagato; Ohno, H.; Petreczky, P.; Schmidt, C.; et al

    2016-01-28

    Here, we calculate the mean and variance of net-baryon number and net-electric charge distributions from quantum chromodynamics (QCD) using a next-to-leading order Taylor expansion in terms of temperature and chemical potentials. Moreover, these expansions with experimental data from STAR and PHENIX are compared, we determine the freeze-out temperature in the limit of vanishing baryon chemical potential, and, for the first time, constrain the curvature of the freeze-out line through a direct comparison between experimental data on net-charge fluctuations and a QCD calculation. We obtain a bound on the curvature coefficient, κmore » $^f$$_2$<0.011, that is compatible with lattice QCD results on the curvature of the QCD transition line.« less

  10. Volume Reflection Dependence of 400 GeV/c Protons on the Bent Crystal Curvature

    SciTech Connect (OSTI)

    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.

  11. Unsteady behavior of locally strained diffusion flames affected by curvature and preferential diffusion

    SciTech Connect (OSTI)

    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.

  12. Flight path-driven mitigation of wavefront curvature effects in SAR images

    DOE Patents [OSTI]

    Doerry, Armin W.

    2009-06-23

    A wavefront curvature effect associated with a complex image produced by a synthetic aperture radar (SAR) can be mitigated based on which of a plurality of possible flight paths is taken by the SAR when capturing the image. The mitigation can be performed differently for different ones of the flight paths.

  13. The Layzer-Irvine equation in theories with non-minimal coupling between matter and curvature

    SciTech Connect (OSTI)

    Bertolami, O.; Gomes, C. E-mail: claudio.gomes@fc.up.pt

    2014-09-01

    We derive the Layzer-Irvine equation for alternative gravitational theories with non-minimal coupling between curvature and matter for an homogeneous and isotropic Universe. As an application, we study the case of Abell 586, a relaxed and spherically symmetric galaxy cluster, assuming some matter density profiles.

  14. Folded membrane dialyzer with mechanically sealed edges

    DOE Patents [OSTI]

    Markley, Finley W.

    1976-01-01

    A semipermeable membrane is folded in accordion fashion to form a stack of pleats and the edges are sealed so as to isolate the opposite surfaces of the membrane. The stack is contained within a case that provides ports for flow of blood in contact with one surface of the membrane through channels formed by the pleats and also provides ports for flow of a dialysate through channels formed by the pleats in contact with the other surface of the membrane. The serpentine side edges of the membrane are sealed by a solidified plastic material, whereas effective mechanical means are provided to seal the end edges of the folded membrane. The mechanical means include a clamping strip which biases case sealing flanges into a sealed relationship with end portions of the membrane near the end edges, which portions extend from the stack and between the sealing flanges.

  15. Beyond Pluto: The Search for the Edge

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    LOS ALAMOS, N.M., July 30, 2015-Los Alamos National Laboratory Fellow and physicist Herb Funsten will explore the edge of the solar system and anticipate its future as it moves ...

  16. Edge Equilibrium Code (EEC) For Tokamaks

    SciTech Connect (OSTI)

    Li, Xujling

    2014-02-24

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

  17. ClearEdge Power | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    ClearEdge Power ClearEdge Power Presented at the Clean Energy States Alliance and U.S. Department of Energy Webinar: Financing Fuel Cell Installations, August 30, 2011. webinaraug30_graham.pdf (788 KB) More Documents & Publications CX-013631: Categorical Exclusion Determination Comments of Tendril Networks Inc Questions and Answers for the Smart Grid Investment Grant Program: Applicability of Buy American Provision of Section 1605 of the Recovery Act to Projects Under the Smart Grid

  18. Breakthrough Time and Mechanical Properties of Edge Sealing in...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Breakthrough Time and Mechanical Properties of Edge Sealing in Different Environmental Conditions Breakthrough Time and Mechanical Properties of Edge Sealing in Different ...

  19. 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 Title: Unbalanced edge modes and topological phase transition in gated trilayer graphene Authors: ...

  20. Stability of edge states in strained graphene (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    Stability of edge states in strained graphene Title: Stability of edge states in strained graphene Authors: Ghaemi, Pouyan ; Gopalakrishnan, Sarang ; Ryu, Shinsei Publication Date: ...

  1. Frozen Bullets Tame Unruly Edge Plasmas in Fusion Experiment...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Frozen Bullets Tame Unruly Edge Plasmas in Fusion Experiment American Fusion News Category: General Atomics (GA) Link: Frozen Bullets Tame Unruly Edge Plasmas in Fusion Experiment...

  2. Subangstrom Edge Relaxations Probed by Electron Microscopy in...

    Office of Scientific and Technical Information (OSTI)

    Subangstrom Edge Relaxations Probed by Electron Microscopy in Hexagonal Boron Nitride Title: Subangstrom Edge Relaxations Probed by Electron Microscopy in Hexagonal Boron Nitride ...

  3. Partnership for Edge Physics Simulation (EPSI)

    SciTech Connect (OSTI)

    Schroder, Peter

    2015-02-11

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

  4. Glenn Seaborg Trail | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    Glenn Seaborg Trail Basic Energy Sciences (BES) BES Home About Organization Chart .pdf file (132KB) Staff BES Budget BES Committees of Visitors Directions Jobs Organizational History Germantown Natural History President Kennedy's AEC Briefings Research Facilities Science Highlights Benefits of BES Funding Opportunities Basic Energy Sciences Advisory Committee (BESAC) Community Resources Contact Information Basic Energy Sciences U.S. Department of Energy SC-22/Germantown Building 1000

  5. Influence of curvature on the device physics of thin film transistors on flexible substrates

    SciTech Connect (OSTI)

    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.

  6. Quantization of a particle on a two-dimensional manifold of constant curvature

    SciTech Connect (OSTI)

    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 Schrdinger equation is separable and the spectrum and eigenfunctions can be investigated in detail.

  7. Effects of bending stresses and tube curvature on remote field eddy current signals

    SciTech Connect (OSTI)

    Sutherland, J.; Atherton, D.L.

    1997-01-01

    The effects of bending stresses and tube curvature on remote field eddy current signals were investigated. This technique is a recognized method for the nondestructive evaluation of ferromagnetic tubing, as used in heat exchangers and boiler systems. Different stress states were examined (elastic stress, plastic deformation, and residual stress) and found to give distinctive behavior. Elastic and residual stresses can appear as wall loss, depending on the operating frequency and baseline used for inspection and interpretation.

  8. Measurement of the curvature of a surface using parallel light beams

    DOE Patents [OSTI]

    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.

  9. Measurement of the curvature of a surface using parallel light beams

    DOE Patents [OSTI]

    Chason, Eric H.; Floro, Jerrold A.; Seager, Carleton H.; Sinclair, Michael B.

    1999-01-01

    Apparatus for measuring curvature of a surface wherein a beam of collimated light is passed through 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.

  10. The effect of ion orbit loss and X-loss on the interpretation of ion energy and particle transport in the DIII-D edge plasma

    SciTech Connect (OSTI)

    Stacey, Weston M.

    2011-10-15

    Calculation models are presented for treating ion orbit loss effects in interpretive fluid transport calculations for the tokamak edge pedestal. Both standard ion orbit loss of particles following trapped or passing orbits across the separatrix and the X-loss of particles that are poloidally trapped in a narrow null-B{sub {theta}} region extending inward from the X-point, where they gradB and curvature drift outward, are considered. Calculations are presented for a representative DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] shot which indicate that ion orbit loss effects are significant and should be taken into account in calculations of present and future experiments.

  11. Strip edge cracking simulation in cold rolling

    SciTech Connect (OSTI)

    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.

  12. The curvature of sensitometric curves for Kodak XV-2 film irradiated with photon and electron beams

    SciTech Connect (OSTI)

    Battum, L. J. van; Huizenga, H.

    2006-07-15

    Sensitometric curves of Kodak XV-2 film, obtained in a time period of ten years with various types of equipment, have been analyzed both for photon and electron beams. The sensitometric slope in the dataset varies more than a factor of 2, which is attributed mainly to variations in developer conditions. In the literature, the single hit equation has been proposed as a model for the sensitometric curve, as with the parameters of the sensitivity and maximum optical density. In this work, the single hit equation has been translated into a polynomial like function as with the parameters of the sensitometric slope and curvature. The model has been applied to fit the sensitometric data. If the dataset is fitted for each single sensitometric curve separately, a large variation is observed for both fit parameters. When sensitometric curves are fitted simultaneously it appears that all curves can be fitted adequately with a sensitometric curvature that is related to the sensitometric slope. When fitting each curve separately, apparently measurement uncertainty hides this relation. This relation appears to be dependent only on the type of densitometer used. No significant differences between beam energies or beam modalities are observed. Using the intrinsic relation between slope and curvature in fitting sensitometric data, e.g., for pretreatment verification of intensity-modulated radiotherapy, will increase the accuracy of the sensitometric curve. A calibration at a single dose point, together with a predetermined densitometer-dependent parameter OD{sub max} will be adequate to find the actual relation between optical density and dose.

  13. Edge rotational magnons in magnonic crystals

    SciTech Connect (OSTI)

    Lisenkov, Ivan Kalyabin, Dmitry; Moscow Institute of Physics and Technology, 9 Instituskij per., Dolgoprudny, 141700 Moscow Region ; Nikitov, Sergey; Moscow Institute of Physics and Technology, 9 Instituskij per., Dolgoprudny, 141700 Moscow Region; Saratov State University, 112 Bol'shaya Kazach'ya, Saratov 410012

    2013-11-11

    It is predicted that in 2D magnonic crystals the edge rotational magnons of forward volume magnetostatic spin waves can exist. Under certain conditions, locally bounded magnons may appear within the crystal consisting of the ferromagnetic matrix and periodically inserted magnetic/non-magnetic inclusions. It is also shown that interplay of different resonances in 2D magnonic crystal may provide conditions for spin wave modes existence with negative group velocity.

  14. Permanent magnet edge-field quadrupole

    DOE Patents [OSTI]

    Tatchyn, R.O.

    1997-01-21

    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. 10 figs.

  15. Permanent magnet edge-field quadrupole

    DOE Patents [OSTI]

    Tatchyn, Roman O.

    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.

  16. Rimmed and edge thickened Stodola shaped flywheel

    DOE Patents [OSTI]

    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.

  17. Cooling Strategies for Vane Leading Edges in a Syngas Environment Including Effects of Deposition and Turbulence

    SciTech Connect (OSTI)

    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

  18. Method for encapsulating the edge of a flexible sheet

    DOE Patents [OSTI]

    Keenihan, James R; Clarey, Todd M

    2013-02-19

    The present invention is premised upon an inventive method of producing an over-molded edge portion on a flexible substrate, wherein the edge portion is void of open areas due to support devices in the mold cavity.

  19. The Bleeding 'Edge' of Fusion Research | Princeton Plasma Physics...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    inward from the plasma edge. To watch the visualization, click the link at the end of the article. Part of a visualization of turbulence spreading inward from the plasma edge. ...

  20. Phantomlike behavior in a brane-world model with curvature effects

    SciTech Connect (OSTI)

    Bouhmadi-Lopez, Mariam; Moniz, Paulo Vargas

    2008-10-15

    Recent observational evidence seems to allow the possibility that our Universe may currently be under a dark energy effect of a phantom nature. A suitable effective phantom fluid behavior can emerge in brane cosmology; in particular, within the normal non-self-accelerating Dvali-Gabadadze-Porrati branch, without any exotic matter and due to curvature effects from induced gravity. The phantomlike behavior is based in defining an effective energy density that grows as the brane expands. This effective description breaks down at some point in the past when the effective energy density becomes negative and the effective equation of state parameter blows up. In this paper we investigate if the phantomlike regime can be enlarged by the inclusion of a Gauss-Bonnet (GB) term into the bulk. The motivation is that such a GB component would model additional curvature effects on the brane setting. More precisely, our aim is to determine if the GB term, dominating and modifying the early behavior of the brane universe, may eventually extend the regime of validity of the phantom mimicry on the brane. However, we show that the opposite occurs: the GB effect seems instead to induce a breakdown of the phantomlike behavior at an even smaller redshift.

  1. Caterpillar and Cummins Gain Edge Through Argonnne's Rare Computer...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Caterpillar and Cummins Gain Edge Through Argonnne's Rare Computer Modeling and Analysis Resources PDF icon catcumminscomputingsuccessstorydec2015...

  2. Edge-based correlation image registration for multispectral imaging

    DOE Patents [OSTI]

    Nandy, Prabal

    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.

  3. Method of forming densified edge seals for fuel cell components

    DOE Patents [OSTI]

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

    1981-01-01

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

  4. Rimmed and edge thickened Stodola shaped flywheel

    DOE Patents [OSTI]

    Kulkarni, Satish V.; Stone, Richard G.

    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.

  5. Towards understanding of Nipah virus attachment protein assembly and the role of protein affinity and crowding for membrane curvature events.

    SciTech Connect (OSTI)

    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.

  6. Using new edges for anomaly detection in computer networks

    DOE Patents [OSTI]

    Neil, Joshua Charles

    2015-05-19

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

  7. Coaxial connector for use with printed circuit board edge connector

    DOE Patents [OSTI]

    Howard, Donald R.; MacGill, Robert A.

    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.

  8. Study The Effect Of Curvature On Spring Back Of Double Curved Steel Sheet Using New Method

    SciTech Connect (OSTI)

    Parsa, M. H.; Kazemi, M.; Pishbin, H.

    2007-05-17

    Spring back is one of main reason for inaccuracy of sheet press formed product. Therefore; prediction of spring back is very important for production of precise products. To calculate the amount of spring back many successful attempts have been done, but unfortunately; most of them belong to the simple cases such as single curved U or V, bending of sheet metals. In this study, an improved yield criterion proposed by Yoshida, have been incorporated in a new formulation for prediction of the spring back in a double curved sheet metal. This criterion is capable to reveal the influence of transient Baushinger effect and work hardening stagnation on spring back analysis. Finally; the effect of some geometrical parameters such as thickness, and curvatures radius will be discussed.

  9. Higher order statistics of curvature perturbations in IFF model and its Planck constraints

    SciTech Connect (OSTI)

    Fujita, Tomohiro; Yokoyama, Shuichiro E-mail: shu@icrr.u-tokyo.ac.jp

    2013-09-01

    We compute the power spectrum P{sub ζ} and non-linear parameters f{sub NL} and τ{sub NL} of the curvature perturbation induced during inflation by the electromagnetic fields in the kinetic coupling model (IFF model). By using the observational result of P{sub ζ},f{sub NL} and τ{sub NL} reported by the Planck collaboration, we study the constraint on the model comprehensively. Interestingly, if the single slow-rolling inflaton is responsible for the observed P{sub ζ}, the constraint from τ{sub NL} is most stringent. We also find a general relationship between f{sub NL} and τ{sub NL} generated in this model. Even if f{sub NL} ∼ O(1), a detectable τ{sub NL} can be produced.

  10. Curvature-Induced Bunch Self-Interaction for an Energy-Chirped Bunch in Magnetic Bends

    SciTech Connect (OSTI)

    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.

  11. Non-Gaussian density fluctuations from entropically generated curvature perturbations in ekpyrotic models

    SciTech Connect (OSTI)

    Lehners, Jean-Luc; Steinhardt, Paul J.

    2008-03-15

    We analyze the non-Gaussian density perturbations generated in ekpyrotic/cyclic models based on heterotic M theory. In this picture, two scalar fields produce nearly scale-invariant entropic perturbations during an ekpyrotic phase that are converted into curvature modes after the ekpyrotic phase is complete and just before the big bang. Both intrinsic nonlinearity in the entropy perturbation and the conversion process contribute to non-Gaussianity. The range of the non-Gaussianity parameter f{sub NL} depends on how gradual the conversion process is and the steepness of the scalar field potential during the ekpyrotic phase. Although a wider range is possible, in principle, natural values of the ekpyrotic parameters combined with a gradual conversion process lead to values of -50 < or approx. f{sub NL} < or approx. +200, typically much greater than slow-roll inflation but within the current observational bounds.

  12. Relativistic static thin dust disks with an inner edge: An infinite family of new exact solutions

    SciTech Connect (OSTI)

    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.

  13. The importance of ion size and electrode curvature on electrical double layers in ionic liquids

    SciTech Connect (OSTI)

    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.

  14. The Importance of Ion Size and Electrode Curvature on Electrical Double Layers in Ionic Liquids

    SciTech Connect (OSTI)

    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.

  15. Edge effects on the electronic properties of phosphorene nanoribbons

    SciTech Connect (OSTI)

    Peng, Xihong; Copple, Andrew; Wei, Qun

    2014-10-14

    Two dimensional few-layer black phosphorus crystal structures have recently been fabricated and have demonstrated great potential in electronic applications. In this work, we employed first principles density functional theory calculations to study the edge and quantum confinement effects on the electronic properties of the phosphorene nanoribbons (PNR). Different edge functionalization groups, such as H, F, Cl, OH, O, S, and Se, in addition to a pristine case were studied for a series of ribbon widths up to 3.5 nm. It was found that the armchair-PNRs (APNRs) are semiconductors for all edge groups considered in this work. However, the zigzag-PNRs (ZPNRs) show either semiconductor or metallic behavior in dependence on their edge chemical species. Family 1 edges (i.e., H, F, Cl, OH) form saturated bonds with P atoms in the APNRs and ZPNRs, and the edge states keep far away from the band gap. However, Family 2 edges (pristine, O, S, Se) form weak unsaturated bonds with the p{sub z} orbital of the phosphorus atoms and bring edge states within the band gap of the ribbons. For the ZPNRs, the edge states of Family 2 are present around the Fermi level within the band gap, which close up the band gap of the ZPNRs. For the APNRs, these edge states are located at the bottom of the conduction band and result in a reduced band gap.

  16. Microchannel Cooled Edge Cladding to Establish an Adiabatic Boundary Condition in a Slab Laser

    DOE Patents [OSTI]

    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.

  17. Space-Variant Post-Filtering for Wavefront Curvature Correction in Polar-Formatted Spotlight-Mode SAR Imagery

    SciTech Connect (OSTI)

    DOREN,NEALL E.

    1999-10-01

    Wavefront curvature defocus effects occur in spotlight-mode SAR imagery when reconstructed via the well-known polar-formatting algorithm (PFA) under certain imaging scenarios. These include imaging at close range, using a very low radar center frequency, utilizing high resolution, and/or imaging very large scenes. Wavefront curvature effects arise from the unrealistic assumption of strictly planar wavefronts illuminating the imaged scene. This dissertation presents a method for the correction of wavefront curvature defocus effects under these scenarios, concentrating on the generalized: squint-mode imaging scenario and its computational aspects. This correction is accomplished through an efficient one-dimensional, image domain filter applied as a post-processing step to PF.4. This post-filter, referred to as SVPF, is precalculated from a theoretical derivation of the wavefront curvature effect and varies as a function of scene location. Prior to SVPF, severe restrictions were placed on the imaged scene size in order to avoid defocus effects under these scenarios when using PFA. The SVPF algorithm eliminates the need for scene size restrictions when wavefront curvature effects are present, correcting for wavefront curvature in broadside as well as squinted collection modes while imposing little additional computational penalty for squinted images. This dissertation covers the theoretical development, implementation and analysis of the generalized, squint-mode SVPF algorithm (of which broadside-mode is a special case) and provides examples of its capabilities and limitations as well as offering guidelines for maximizing its computational efficiency. Tradeoffs between the PFA/SVPF combination and other spotlight-mode SAR image formation techniques are discussed with regard to computational burden, image quality, and imaging geometry constraints. It is demonstrated that other methods fail to exhibit a clear computational advantage over polar-formatting in conjunction

  18. Lab Enhances Scientific Data Sharing with Cutting-Edge Connection |

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jefferson Lab Enhances Scientific Data Sharing with Cutting-Edge Connection Lab Enhances Scientific Data Sharing with Cutting-Edge Connections September 21, 2006 Cutting-Edge Andy Kowalski holds a 10 Gigabit fiber-optic cable. Newport News, Va. - Scientists who conduct research at the Department of Energy's (DOE's) Thomas Jefferson National Accelerator Facility can now access and share research data faster than ever before, thanks to an upgraded Internet connection that provides data

  19. Integral edge seals for phosphoric acid fuel cells

    DOE Patents [OSTI]

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

    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.

  20. NNSA's Cutting Edge Science and Research on Display at Annual...

    National Nuclear Security Administration (NNSA)

    NNSA's Cutting Edge Science and Research on Display at Annual AAAS Meeting February 17, ... newly elected fellows at the American Association for the Advancement of Science (AAAS). ...

  1. PPPL researchers present cutting edge results at APS Plasma Physics...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    PPPL researchers present cutting edge results at APS Plasma Physics Conference November ... Gallery: Fast-camera image showing plasma during magnetic reconnection. Fast-camera image ...

  2. SolarEdge Technologies Inc | Open Energy Information

    Open Energy Info (EERE)

    search Name: SolarEdge Technologies Inc Place: Hod Hasharon, Israel Zip: 45240 Sector: Solar Product: Israel-based startup developing a power control system for solar systems,...

  3. Research Led by Sandia Reveals Leading-Edge Erosion Significantly...

    Broader source: Energy.gov (indexed) [DOE]

    Laboratories revealed that leading-edge erosion on wind turbine blades can have a detrimental effect on wind turbine aerodynamic performance within the second year of operation. ...

  4. Session #1: Cutting Edge Methodologies--Beyond Current DFT

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Session 1: Cutting Edge Methodologies (beyond Current DFT) Moderator: Shengbai Zhang (RPI REL) Topics to be addressed: Benchmarking state-of-the-art approaches, accurate energy ...

  5. Edge Plasma Boundary Layer Generated By Kink Modes in Tokamaks

    SciTech Connect (OSTI)

    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.

  6. Edge Turbulence Velocity Changes with Lithium Coating on NSTX

    SciTech Connect (OSTI)

    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. __________________________________________________

  7. Edge-localized-modes in tokamaks

    SciTech Connect (OSTI)

    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.

  8. Feynman-like rules for calculating n-point correlators of the primordial curvature perturbation

    SciTech Connect (OSTI)

    Valenzuela-Toledo, Csar A.; Rodrguez, Yeinzon; Almeida, Juan P. Beltrn 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.

  9. 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 Puf5p–RNA 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

  10. RNA regulatory networks diversified through curvature of the PUF protein scaffold

    SciTech Connect (OSTI)

    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 Puf5p–RNA complexes reveal that the protein scaffold presents an exceptionally flat and extended 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.

  11. Edge profile measurements using Thomson scattering on the KSTAR tokamak

    SciTech Connect (OSTI)

    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.

  12. Edge states and phase diagram for graphene under polarized light

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wang, Yi -Xiang; Li, Fuxiang

    2016-03-22

    In this paper, we investigate the topological phase transitions in graphene under the modulation of circularly polarized light, by analyzing the changes of edge states and its topological structures. A full phase diagram, with several different topological phases, is presented in the parameter space spanned by the driving frequency and light strength. We find that the high-Chern number behavior is very common in the driven system. While the one-photon resonance can create the chiral edge states in the π-gap, the two-photon resonance will induce the counter-propagating edge modes in the zero-energy gap. When the driving light strength is strong, themore » number and even the chirality of the edge states may change in the π-gap. The robustness of the edge states to disorder potential is also examined. We close by discussing the feasibility of experimental proposals.« less

  13. Aerodynamic analysis of propeller-type windmills with helical trailing vortices

    SciTech Connect (OSTI)

    Shiao, T.C.

    1980-01-01

    To improve the strip theory for computing the performance of a propeller-type windmill, a more realistic analysis is formulated to include the wake effect. In this dissertation, the finite-wing theory is applied to a rotor blade to find its circulation distribution with the downwash determined from a direct integration of Biot-Savart's law based on the entire helical trailing vortex system. Since no simple analytical solutions can be found for the circulation and the interference factors along a windmill blade, an iterative procedure has been developed to determine the sectional properties at some selected stations. A computer program is constructed for the computation, in which the empirical lift and drag data of the blade airfoil section are programmed. The torque, thrust and power output of the windmill are then obtained by integrating the sectional aerodynamic properties from hub to tip along the blades. Two windmills, one with twisted and tapered blades and the other with uniform blades, are used as examples in predicting the performances. The power computed for the latter windmill agrees well with the measured data. It has been found, according to the computations for the first windmill, that the helical wake may cause a reduction up to 30% in power output of the windmill. The problems of finding the optimum pitch angle for a uniform blade and the optimum distribution of twist angle for a blade of constant chord are considered as some applications of the method derived in this dissertation.

  14. Geometric Gyrokinetic Theory for Edge Plasma

    SciTech Connect (OSTI)

    Qin, H; Cohen, R H; Nevins, W M; Xu, X Q

    2007-01-18

    It turns out that gyrokinetic theory can be geometrically formulated as special cases of a geometrically generalized Vlasov-Maxwell system. It is proposed that the phase space of the spacetime is a 7-dimensional fiber bundle P over the 4-dimensional spacetime M, and that a Poincare-Cartan-Einstein 1-form {gamma} on the 7-dimensional phase space determines particles worldlines in the phase space. Through Liouville 6-form {Omega} and fiber integral, the 1-form {gamma} also uniquely defines a geometrically generalized Vlasov-Maxwell system as a field theory for the collective electromagnetic field. The geometric gyrokinetic theory is then developed as a special case of the geometrically generalized Vlasov-Maxwell system. In its most general form, gyrokinetic theory is about a symmetry, called gyro-symmetry, for magnetized plasmas, and the 1-form {gamma} again uniquely defines the gyro-symmetry. The objective is to decouple the gyro-phase dynamics from the rest of particle dynamics by finding the gyro-symmetry in {gamma}. Compared with other methods of deriving the gyrokinetic equations, the advantage of the geometric approach is that it allows any approximation based on mathematical simplification or physical intuition to be made at the 1-form level, and yet the field theories still have the desirable exact conservation properties such as phase space volume conservation and energy-momentum conservation if the 1-form does not depend on the spacetime coordinate explicitly. A set of generalized gyrokinetic equations valid for the edge plasmas is then derived using this geometric method. This formalism allows large-amplitude, time-dependent background electromagnetic fields to be developed fully nonlinearly in addition to small-amplitude, short-wavelength electromagnetic perturbations. The fact that we adopted the geometric method in the present study does not necessarily imply that the major results reported here can not be achieved using classical methods. What the

  15. Curvature Effect on the Capacitance of Electric Double Layers at Ionic Liquid/Onion-Like Carbon Interfaces

    SciTech Connect (OSTI)

    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.

  16. Automatic meshing of curved three-dimensional domains: Curving finite elements and curvature-based mesh control

    SciTech Connect (OSTI)

    Shephard, M.S.; Dey, S.; Georges, M.K.

    1995-12-31

    Specific issues associated with the automatic generation of finite element meshes for curved geometric domains axe considered. A review of the definition of when a triangulation is a valid mesh, a geometric triangulation, for curved geometric domains is given. Consideration is then given to the additional operations necessary to maintain the validity of a mesh when curved finite elements are employed. A procedure to control the mesh gradations based on the curvature of the geometric model faces is also given.

  17. Curvature and ionization-induced reversible hydrogen storage in metalized hexagonal B{sub 36}

    SciTech Connect (OSTI)

    Liu, Chun-Sheng Wang, Xiangfu; Yan, Xiaohong; Ye, Xiao-Juan; Zeng, Zhi

    2014-11-21

    The synthesis of quasiplanar boron clusters (B{sub 36}) with a central hexagonal hole provides the first experimental evidence that a single-atomic-layer borophene with hexagonal vacancies is potentially viable [Z. Piazza, H. Hu, W. Li, Y. Zhao, J. Li, and L. S. Wang, Nat. Commun. 5, 3113 (2014)]. However, owing to the hexagonal holes, tunning the electronic and physical properties of B{sub 36} through chemical modifications is not fully understood. Based on (van der Waals corrected-) density functional theory, we show that Li adsorbed on B{sub 36} and B{sub 36}{sup ?} clusters can serve as reversible hydrogen storage media. The present results indicate that the curvature and ionization of substrates can enhance the bond strength of Li due to the energetically favorable B 2p-Li 2p orbitals hybridization. Both the polarization mechanism and the orbital hybridization between H-s orbitals and Li-2s2p orbitals contribute to the adsorption of H{sub 2} molecules and the resulting adsorption energy lies between the physisorbed and chemisorbed states. Interestingly, the number of H{sub 2} in the hydrogen storage medium can be measured by the appearance of the negative differential resistance behavior at different bias voltage regions. Furthermore, the cluster-assembled hydrogen storage materials constructed by metalized B{sub 36} clusters do not cause a decrease in the number of adsorbed hydrogen molecules per Li. The system reported here is favorable for the reversible hydrogen adsorption/desorption at ambient conditions.

  18. Reconstruction of the primordial power spectrum of curvature perturbations using multiple data sets

    SciTech Connect (OSTI)

    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.

  19. Improvement of the edge rotation diagnostic spectrum analysis via simulation

    SciTech Connect (OSTI)

    Luo, J.; Zhuang, G. Cheng, Z. F.; Zhang, X. L.; Hou, S. Y.; Cheng, C.

    2014-11-15

    The edge rotation diagnostic (ERD) system has been developed on the Joint Texas Experimental Tokamak to measure the edge toroidal rotation velocity by observing the shifted wavelength of carbon V (C V 227.09 nm). Since the measured spectrum is an integrated result along the viewing line from the plasma core to the edge, a method via simulation has been developed to analyze the ERD spectrum. With the necessary parameters such as C V radiation profile and the ion temperature profile, a local rotation profile at the normalized minor radius of 0.5-1 is obtained.

  20. SciDAC Center for Plasma Edge Simulation

    SciTech Connect (OSTI)

    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.

  1. Nonlinear gyrofluid computation of edge localized ideal ballooning modes

    SciTech Connect (OSTI)

    Kendl, Alexander; Scott, Bruce D.; Ribeiro, Tiago T.

    2010-07-15

    Three-dimensional electromagnetic gyrofluid simulations of the ideal ballooning mode blowout scenario for tokamak edge localized modes are presented. Special emphasis is placed on diagnosis of the linear, overshoot, and decay phases. The saturation process is energy transfer to self-generated edge turbulence, which exhibits an ion temperature gradient mode structure. Convergence in the decay phase is found only if the spectrum reaches the ion gyroradius. The equilibrium is a self-consistent background whose evolution is taken into account. Approximately two-thirds of the total energy in the edge layer is liberated in the blowout. Parameter dependence with respect to plasma pressure and the ion gyroradius is studied. Despite the violent nature of the short-lived process, the transition to nonlinearity is very similar to that found in generic tokamak edge turbulence.

  2. Leading Edge Erosion Phase II Wind Tunnel Test Begins

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... Wind tunnel testing is commencing for the second phase of the leading edge erosion project, which is a collaboration between Texas A&M, UC Davis, and Sandia. During the 2012 fiscal ...

  3. Electron spin magnetism of zigzag graphene nanoribbon edge states

    SciTech Connect (OSTI)

    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 α and β 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.

  4. PROJECT PROFILE: EdgePower (Incubator 10) | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    As a result, EdgePower will be able to better match PV supply with building demand and reduce peak demand at the utility meter. This project will combine site-based solar forecast ...

  5. Edge Temperature Gradient as Intrinsic Rotation Drive in Alcator...

    Office of Scientific and Technical Information (OSTI)

    Title: Edge Temperature Gradient as Intrinsic Rotation Drive in Alcator C -Mod Tokamak Plasmas Authors: Rice, J. E. ; Hughes, J. W. ; Diamond, P. H. ; Kosuga, Y. ; Podpaly, Y. A. ; ...

  6. Transcript, Keeping the Edge: Enhancing Performance by Managing Culture

    Broader source: Energy.gov [DOE]

    Transcript: 2003 INPO CEO Conference, Keeping the Edge: “Enhancing Performance by Managing Culture” Edgar H. Schein, Ph.D. Professor Emeritis, Massachusetts Institute of Technology November 7, 2003

  7. 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...

  8. Hot Rolling Scrap Reduction through Edge Cracking and Surface Defects

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Control | Department of Energy Hot Rolling Scrap Reduction through Edge Cracking and Surface Defects Control Hot Rolling Scrap Reduction through Edge Cracking and Surface Defects Control hot_rolling.pdf (541.63 KB) More Documents & Publications ITP Aluminum: Aluminum Industry Roadmap for the Automotive Market (May 1999) Vehicle Technologies Office: 2012 Lightweight Materials R&D Annual Progress Report ITP Aluminum: Aluminum Industry Technology Roadmap

  9. High-Fidelity Simulation of Tokamak Edge Plasma Transport | Argonne

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Leadership Computing Facility region, obtained from the gyrokinetic code XGC1 Plasma density fluctuation from large amplitude nonlinear turbulence in the tokamak edge region, obtained from the gyrokinetic code XGC1 Simulation by S. Ku, and visualization by D. Pugmire, Oak Ridge National Laboratory High-Fidelity Simulation of Tokamak Edge Plasma Transport PI Name: Choong-Seock Chang PI Email: cschang@pppl.gov Institution: Princeton Plasma Physics Laboratory Allocation Program: INCITE

  10. High-fidelity Simulation of Tokamak Edge Plasma Transport | Argonne

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Leadership Computing Facility region Plasma density fluctuation from large amplitude nonlinear turbulence in the tokamak edge region, obtained from the gyrokinetic code XGC1. Simulation by S. Ku, and visualization by D. Pugmire, Oak Ridge National Laboratory High-fidelity Simulation of Tokamak Edge Plasma Transport PI Name: Choong-Seock Chang PI Email: cschang@pppl.gov Institution: Princeton Plasma Physics Laboratory Allocation Program: INCITE Allocation Hours at ALCF: 100 Million Year: 2015

  11. Breakthrough Time and Mechanical Properties of Edge Sealing in Different

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Environmental Conditions | Department of Energy Breakthrough Time and Mechanical Properties of Edge Sealing in Different Environmental Conditions Breakthrough Time and Mechanical Properties of Edge Sealing in Different Environmental Conditions Presented at the PV Module Reliability Workshop, February 26 - 27 2013, Golden, Colorado pvmrw13_ps4_saes_bonucci.pdf (1.59 MB) More Documents & Publications Agenda for the PV Module Reliability Workshop, February 26 - 27 2013, Golden, Colorado A

  12. Leading Edge Technology in Diesel Emissions Control | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Leading Edge Technology in Diesel Emissions Control Leading Edge Technology in Diesel Emissions Control Poster presented at the 16th Directions in Engine-Efficiency and Emissions Research (DEER) Conference in Detroit, MI, September 27-30, 2010. p-02_roberts.pdf (193.56 KB) More Documents & Publications NO2 Management in Diesel Exhaust System Experimental Evaluation of DOC Performance Using Secondary Fuel Injection Low Temperature Catalyst for Fuel Injection System

  13. Combined Individual Pitch Control

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Figure 2. Conventional trailing edge airfoil (left) and morphing wing trailing edge concept (right) with 20% chord 20 rotation III. 5MW UpWind Reference Wind Turbine...

  14. Oscillations of a Turbulent Jet Incident Upon an Edge

    SciTech Connect (OSTI)

    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

  15. 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...

  16. Topological system with a twisting edge band: A position-dependent...

    Office of Scientific and Technical Information (OSTI)

    Topological system with a twisting edge band: A position-dependent Hall resistance Citation Details In-Document Search Title: Topological system with a twisting edge band: A ...

  17. Modelling of edge localised modes and edge localised mode control [Modelling of ELMs and ELM control

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

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

    2015-02-07

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

  18. Tungsten dust impact on ITER-like plasma edge

    SciTech Connect (OSTI)

    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.

  19. Tungsten dust impact on ITER-like plasma edge

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Smirnov, R. D.; Krasheninnikov, S. I.; Pigarov, A. Yu.; Rognlien, T. D.

    2015-01-12

    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 impactmore » 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. Lastly, 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.« less

  20. Tungsten dust impact on ITER-like plasma edge

    SciTech Connect (OSTI)

    Smirnov, R. D.; Krasheninnikov, S. I.; Pigarov, A. Yu.; Rognlien, T. D.

    2015-01-12

    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. Lastly, 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.

  1. Progress with the COGENT Edge Kinetic Code: Collision operator options

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dorf, M. A.; Cohen, R. H.; Compton, J. C.; Dorr, M.; Rognlien, T. D.; Angus, J.; Krasheninnikov, S.; Colella, P.; Martin, D.; McCorquodale, P.

    2012-06-27

    In this study, COGENT is a continuum gyrokinetic code for edge plasmas being developed by the Edge Simulation Laboratory collaboration. The code is distinguished by application of the fourth order conservative discretization, and mapped multiblock grid technology to handle the geometric complexity of the tokamak edge. It is written in v∥-μ (parallel velocity – magnetic moment) velocity coordinates, and making use of the gyrokinetic Poisson equation for the calculation of a self-consistent electric potential. In the present manuscript we report on the implementation and initial testing of a succession of increasingly detailed collision operator options, including a simple drag-diffusion operatormore » in the parallel velocity space, Lorentz collisions, and a linearized model Fokker-Planck collision operator conserving momentum and energy (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)« less

  2. Composite polymer: Glass edge cladding for laser disks

    DOE Patents [OSTI]

    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.

  3. A survey of problems in divertor and edge plasma theory

    SciTech Connect (OSTI)

    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.

  4. A survey of problems in divertor and edge plasma theory

    SciTech Connect (OSTI)

    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.

  5. Composite polymer-glass edge cladding for laser disks

    DOE Patents [OSTI]

    Powell, Howard T.; Riley, Michael O.; Wolfe, Charles R.; Lyon, Richard E.; Campbell, John H.; Jessop, Edward S.; Murray, James E.

    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.

  6. Edge turbulence and transport: Text and ATF modeling

    SciTech Connect (OSTI)

    Ritz, C.P.; Rhodes, T.L.; Lin, H.; Rowan, W.L.; Bengtson, R.; Wootton, A.J. . Fusion Research Center); Carreras, B.A.; Leboeuf, J.N.; Lee, D.K.; Harris, J.; Hidalgo, C.; Bell, J.D.; Holmes, J.A.; Isler, R.; Lynch, V.E.; Uckan, T. ); Diamond, P.H.; Ware, A.S. ); Thayer, D.R. (Science Applications Inter

    1990-01-01

    We present experimental results on edge turbulence and transport from the tokamak TEXT and the torsatron ATF. The measured electrostatic fluctuations can explain the edge transport of particles and energy. Certain drive (radiation) and stabilizing (velocity shear) terms are suggested by the results. The experimental fluctuation levels and spectral widths can be reproduced by considering the nonlinear evolution of the reduced MHD equations, incorporating a thermal drive from line radiation. In the tokamak limit (with toroidal electric field) the model corresponds to the resistivity gradient mode, while in the currentless torsatron or stellarator limit it corresponds to a thermally driven drift wave.

  7. Ramp-edge structured tunneling devices using ferromagnet electrodes

    DOE Patents [OSTI]

    Kwon, Chuhee; Jia, Quanxi

    2002-09-03

    The fabrication of ferromagnet-insulator-ferromagnet magnetic tunneling junction devices using a ramp-edge geometry based on, e.g., (La.sub.0.7 Sr.sub.0.3) MnO.sub.3, ferromagnetic electrodes and a SrTiO.sub.3 insulator is disclosed. The maximum junction magnetoresistance (JMR) as large as 23% was observed below 300 Oe at low temperatures (T<100 K). These ramp-edge junctions exhibited JMR of 6% at 200 K with a field less than 100 Oe.

  8. Method and system for edge cladding of laser gain media

    DOE Patents [OSTI]

    Bayramian, Andrew James; Caird, John Allyn; Schaffers, Kathleen Irene

    2014-03-25

    A gain medium operable to amplify light at a gain wavelength and having reduced transverse ASE includes an input surface and an output surface opposing the input surface. The gain medium also includes a central region including gain material and extending between the input surface and the output surface along a longitudinal optical axis of the gain medium. The gain medium further includes an edge cladding region surrounding the central region and extending between the input surface and the output surface along the longitudinal optical axis of the gain medium. The edge cladding region includes the gain material and a dopant operable to absorb light at the gain wavelength.

  9. Automated edge finishing using an active XY table

    DOE Patents [OSTI]

    Loucks, Clifford S.; Starr, Gregory P.

    1993-01-01

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

  10. Predicting the Performance of Edge Seal Materials for PV (Presentation)

    SciTech Connect (OSTI)

    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.

  11. Flexible edge seal for vacuum insulating glazing units

    DOE Patents [OSTI]

    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.

  12. Nitrogen K-edge x-ray absorption near edge structure of pyrimidine-containing nucleotides in aqueous solution

    SciTech Connect (OSTI)

    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.

  13. Patterned helical metallic ribbon for continuous edge winding applications

    DOE Patents [OSTI]

    Liebermann, Howard H.; Frischmann, Peter G.; Rosenberry, Jr., George M.

    1983-04-19

    Metallic ribbon having cutout patterns therein is provided in continuous helical form. The cutout patterns may be situated to intersect either or both of the ribbon edges or may be situated entirely within the ribbon. The helical ribbon with the cutout patterns may additionally have a nesting, or self-stacking, feature.

  14. SciDAC-Center for Plasma Edge Simulation

    SciTech Connect (OSTI)

    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. Itâ??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.

  15. On square-integrability of solutions of the stationary Schrödinger equation for the quantum harmonic oscillator in two dimensional constant curvature spaces

    SciTech Connect (OSTI)

    Noguera, Norman; Rózga, Krzysztof

    2015-07-15

    In this work, one provides a justification of the condition that is usually imposed on the parameters of the hypergeometric equation, related to the solutions of the stationary Schrödinger equation for the harmonic oscillator in two-dimensional constant curvature spaces, in order to determine the solutions which are square-integrable. One proves that in case of negative curvature, it is a necessary condition of square integrability and in case of positive curvature, a necessary condition of regularity. The proof is based on the analytic continuation formulas for the hypergeometric function. It is observed also that the same is true in case of a slightly more general potential than the one for harmonic oscillator.

  16. The rheology and processing of edge sheared colloidal polymer opals

    SciTech Connect (OSTI)

    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.

  17. SciDAC - Center for Plasma Edge Simulation - Project Summary

    SciTech Connect (OSTI)

    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.

  18. Electricity Transmission, Pipelines, and National Trails. An Analysis of Current and Potential Intersections on Federal Lands in the Eastern United States, Alaska, and Hawaii

    SciTech Connect (OSTI)

    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

  19. Edge-states ferromagnetism of WS{sub 2} nanosheets

    SciTech Connect (OSTI)

    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.

  20. Enhancing Community Detection By Affinity-based Edge Weighting Scheme

    SciTech Connect (OSTI)

    Yoo, Andy; Sanders, Geoffrey; Henson, Van; Vassilevski, Panayot

    2015-10-05

    Community detection refers to an important graph analytics problem of finding a set of densely-connected subgraphs in a graph and has gained a great deal of interest recently. The performance of current community detection algorithms is limited by an inherent constraint of unweighted graphs that offer very little information on their internal community structures. In this paper, we propose a new scheme to address this issue that weights the edges in a given graph based on recently proposed vertex affinity. The vertex affinity quantifies the proximity between two vertices in terms of their clustering strength, and therefore, it is ideal for graph analytics applications such as community detection. We also demonstrate that the affinity-based edge weighting scheme can improve the performance of community detection algorithms significantly.

  1. Fundamental edge broadening effects during focused electron beam induced nanosynthesis

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Schmied, Roland; Fowlkes, Jason Davidson; Winkler, Robert; Rack, Phillip D.; Plank, Harald

    2015-02-16

    In this study, we explore lateral broadening effects of 3D structures fabricated through focused electron beam induced deposition using MeCpPt(IV)Me3 precursor. In particular, the scaling behavior of proximity effects as a function of the primary electron energy and the deposit height is investigated through experiments and validated through simulations. Correlated Kelvin force microscopy and conductive atomic force microscopy measurements identified conductive and non-conductive proximity regions. It was determined that the highest primary electron energies enable the highest edge sharpness while lower energies contain a complex convolution of broadening effects. In addition, it is demonstrated that intermediate energies lead to evenmore » more complex proximity effects that significantly reduce lateral edge sharpness and thus should be avoided if desiring high lateral resolution.« less

  2. Framework Application for Core-Edge Transport Simulations

    Energy Science and Technology Software Center (OSTI)

    2007-06-13

    FACETS is a whole-device model for magnetic-fusion experiments (including ITER) combining physics effects from sources & sinks, wall effects, edge effects, and core effects in an advanced parallel framework which manages allocation of parallel resources, performs runtime performance analysis, and provides tools for interactive steering and visualization. FACETS will be used by fusion researchers to design experimental campaigns, predict and model fusion experimental phenomena, and design and optimize future machines.

  3. PPPL researchers present cutting edge results at APS Plasma Physics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Conference | Princeton Plasma Physics Lab PPPL researchers present cutting edge results at APS Plasma Physics Conference November 10, 2014 Tweet Widget Google Plus One Share on Facebook Conceptual image of the solar wind from the sun encountering the Earth's magnetosphere. Conceptual image of the solar wind from the sun encountering the Earth's magnetosphere. Gallery: Fast-camera image showing plasma during magnetic reconnection. Fast-camera image showing plasma during magnetic reconnection.

  4. Hot compression process for making edge seals for fuel cells

    DOE Patents [OSTI]

    Dunyak, Thomas J.; Granata, Jr., Samuel J.

    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.

  5. Rimmed and edge thickened stodola shaped flywheel. [Patent application

    DOE Patents [OSTI]

    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.

  6. Simulation of carbon gasification kinetics using an edge recession model

    SciTech Connect (OSTI)

    Takashi Kyotani; Leon y Leon, C.A.L.; Radovic, L.R. )

    1993-07-01

    An edge recession modeling method is proposed as a new approach to the prediction of carbon gasification kinetics. Using this method, the variations in reactive surface area (RSA) and specific reactivity (R) with conversion were simulated for several polynuclear aromatic molecules adopted as models of carbon crystallites. The effects of crystallite size and shape, edge site reactivity and vacancies on the changes in RSA and R with conversion were investigated. As a result, RSA and R were found to be essentially independent of crystallite shape, but to depend on crystallite size and the presence of vacancies. Good agreement was obtained between model predictions and experimental data for several kinds of model carbon crystallites. In the case of structurally disordered carbons (such as chars), simultaneous gasification of model crystallites of two different sizes gave better predictions than that of single-size crystallites. The edge recession model is proposed as an alternative, or at least complementary, approach to the more conventional (and, arguably, less physically meaningful) pore structure development models.

  7. 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

  8. NPR: Particles From The Edge Of Space Shine A Light On Fukushima

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    NPR: Particles From The Edge Of Space Shine A Light On Fukushima NPR: Particles From The Edge Of Space Shine A Light On Fukushima It's one of the greatest, and most disturbing, ...

  9. NPR: Particles From The Edge Of Space Shine A Light On Fukushima

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    NPR: Particles From The Edge Of Space Shine A Light On Fukushima August 30, 2015 NPR: Particles From The Edge Of Space Shine A Light On Fukushima It's one of the greatest, and most ...

  10. Spin-polarized and valley helical edge modes in graphene nanoribbons...

    Office of Scientific and Technical Information (OSTI)

    Spin-polarized and valley helical edge modes in graphene nanoribbons Citation Details In-Document Search Title: Spin-polarized and valley helical edge modes in graphene nanoribbons ...

  11. Thin planar package for cooling an array of edge-emitting laser...

    Office of Scientific and Technical Information (OSTI)

    Thin planar package for cooling an array of edge-emitting laser diodes Title: Thin planar package for cooling an array of edge-emitting laser diodes A laser diode array is ...

  12. Luminescence from Edge Fracture in Shocked Lithium Fluoride Crystals

    SciTech Connect (OSTI)

    Turley, W. D.; Stevens, G. D.; Capelle, G. A.; Grover, M.; Holtkamp, D. B.; LaLone, B. M.; Veeser, L. R.

    2013-01-01

    Light emitted from a [100] lithium fluoride crystal was characterized under shock wave compression to 28GPa followed by complete stress release at the edges. The light was examined using time-gated optical spectrometry and imaging, time-resolved optical emission measurements, and hydrodynamic modeling. The shock arrival at the circumference of the crystal was delayed relative to the center so that the two regions could be studied at different times. The majority of the light emission originated when the shock waves released at the circumference of the crystal. Unlike previously reported results for shocked lithium fluoride, we found that the light spectrum is not strictly broad band, but has spectral lines associated with atomic lithium in addition to a broad band background. Also, the emission spectrum depends strongly on the gas surrounding the sample. Based on our observations, the line emission appears to be related to fracture of the lithium fluoride crystal from the shock wave releasing at the edges. Experimenters frequently utilize lithium fluoride crystals as transparent windows for observing shock compressed samples. Because of the experimental geometries used, the shock wave in such cases often reaches the circumference of the window at nearly the same moment as when it reaches the center of the sample-window interface. Light generated at the circumference could contaminate the measurement at the interface when this light scatters into the observed region. This background light may be reduced or avoided using experimental geometries which delay the arrival of the shock wave at the edges of the crystal.

  13. Coarse-grained molecular dynamics study of membrane fusion: Curvature effects on free energy barriers along the stalk mechanism

    SciTech Connect (OSTI)

    Kawamoto, Shuhei; Shinoda, Wataru; Klein, Michael L.

    2015-12-28

    The effects of membrane curvature on the free energy barrier for membrane fusion have been investigated using coarse-grained molecular dynamics (CG-MD) simulations, assuming that fusion takes place through a stalk intermediate. Free energy barriers were estimated for stalk formation as well as for fusion pore formation using the guiding potential method. Specifically, the three different geometries of two apposed membranes were considered: vesicle–vesicle, vesicle–planar, and planar–planar membranes. The free energy barriers for the resulting fusion were found to depend importantly on the fusing membrane geometries; the lowest barrier was obtained for vesicular membranes. Further, lipid sorting was observed in fusion of the mixed membranes of dimyristoyl phosphatidylcholine and dioleoyl phosphatidylethanolamine (DOPE). Specifically, DOPE molecules were found to assemble around the stalk to support the highly negative curved membrane surface. A consistent result for lipid sorting was observed when a simple continuum model (CM) was used, where the Helfrich energy and mixing entropy of the lipids were taken into account. However, the CM predicts a much higher free energy barrier than found using CG-MD. This discrepancy originates from the conformational changes of lipids, which were not considered in the CM. The results of the CG-MD simulations reveal that a large conformational change in the lipid takes place around the stalk region, which results in a reduction of free energy barriers along the stalk mechanism of membrane fusion.

  14. 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.

  15. Interacting spins and holes in zigzag edge nanographene

    SciTech Connect (OSTI)

    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.

  16. Experimental characterization of edge force on the Crookes radiometer

    SciTech Connect (OSTI)

    Ventura, Austin L.; Ketsdever, Andrew D.; Gimelshein, Natalia E.; Gimelshein, Sergey F.

    2014-12-09

    The contribution of edge force on the Crookes radiometer is experimentally investigated with three vane geometries. This work examines increasing the force per unit weight of a radiometer vane for applications such as near-space propulsion by increasing the vanes perimeter while decreasing the total surface area of the vane by means of machined holes in the vanes. Experimental results are given for three vane geometries. These results indicate that although force to vane weight ratios can be improved, the maximum force is achieved by a vane geometry that contains no hole features.

  17. Grid of the Future: Controlling the Edge | Argonne National Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Grid of the Future: Controlling the Edge September 6, 2016 10:00AM to 11:00AM Presenter Sonja Glavaski, ARPA-E Location Building 241, Room D172 Type Seminar Series EGS Seminar Abstract: The evolution of the grid faces significant challenges if it is to integrate and accept more energy from renewable generation and other distributed energy resources (DERs). To maintain grid reliability and turn intermittent power sources into major contributors to the U.S. energy mix, we have to think about the

  18. Low-temperature random matrix theory at the soft edge

    SciTech Connect (OSTI)

    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.

  19. Growing Cutting-edge X-ray Optics

    ScienceCinema (OSTI)

    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

  20. Fuel cell cooler assembly and edge seal means therefor

    DOE Patents [OSTI]

    Breault, Richard D.; Roethlein, Richard J.; Congdon, Joseph V.

    1980-01-01

    A cooler assembly for a stack of fuel cells comprises a fibrous, porous coolant tube holder sandwiched between and bonded to at least one of a pair of gas impervious graphite plates. The tubes are disposed in channels which pass through the holder. The channels are as deep as the holder thickness, which is substantially the same as the outer diameter of the tubes. Gas seals along the edges of the holder parallel to the direction of the channels are gas impervious graphite strips.

  1. Polarized micro Raman scattering spectroscopy for curved edges of epitaxial graphene

    SciTech Connect (OSTI)

    Islam, Md. Sherajul Makino, T.; Hashimoto, A.; Bhuiyan, A. G.; Tanaka, S.

    2014-12-15

    This letter performed polarized microscopic laser Raman scattering spectroscopy on the curved edges of transferred epitaxial graphene on SiO{sub 2}/Si. The intensity ratio between the parallel and perpendicular polarized D band is evolved, providing a spectroscopy-based technique to probe the atomic-scale edge structures in graphene. A detailed analysis procedure for non-ideal disordered curved edges of graphene is developed combining the atomic-scale zigzag and armchair edge structures along with some point defects. These results could provide valuable information of the realistic edges of graphene at the atomic-scale that can strongly influence the performance of graphene-based nanodevices.

  2. Edge coating apparatus with movable roller applicator for solar cell substrates

    DOE Patents [OSTI]

    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.

  3. Framework Application for Core Edge Transport Simulation (FACETS)

    SciTech Connect (OSTI)

    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.

  4. ALTERNATIVE MATERIALS FOR RAMP-EDGE SNS JUNCTIONS

    SciTech Connect (OSTI)

    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.

  5. Theoretic base of Edge Local Mode triggering by vertical displacements

    SciTech Connect (OSTI)

    Wang, Z. T.; He, Z. X.; Wang, Z. H.; Wu, N.; Tang, C. J.

    2015-05-15

    Vertical instability is studied with R-dependent displacement. For Solovev's configuration, the stability boundary of the vertical instability is calculated. The pressure gradient is a destabilizing factor which is contrary to Rebhan's result. Equilibrium parallel current density, j{sub //}, at plasma boundary is a drive of the vertical instability similar to Peeling-ballooning modes; however, the vertical instability cannot be stabilized by the magnetic shear which tends towards infinity near the separatrix. The induced current observed in the Edge Local Mode (ELM) triggering experiment by vertical modulation is derived. The theory provides some theoretic explanation for the mitigation of type-I ELMS on ASDEX Upgrade. The principle could be also used for ITER.

  6. Fluid simulations of edge turbulence for stellarators and axisymmetric configurations

    SciTech Connect (OSTI)

    Kleiber, R.; Scott, B.

    2005-10-01

    Nonlinear electromagnetic fluid simulations in a flux tube are used to compute the edge turbulence for a family of axisymmetric configurations with different rotational transform profiles ({iota}) and the stellarator Wendelstein 7-X (W7-X) [Grieger et al., Plasma Physics and Controlled Nuclear Fusion Research, 1990 (International Atomic Energy Agency, Vienna, 1991), Vol. 3, p. 525]. The influence of the {iota} profile on anomalous transport and the strength of zonal flows in these axisymmetric equilibria are studied and the results are connected to simulations for the W7-X equilibrium. A strong decrease in transport is found by increasing {iota} or switching the sign of the shear from tokamak-({iota}{sup '}<0) to stellarator-like ({iota}{sup '}>0). The effect of pressure-induced changes in the W7-X equilibrium geometry on the transport at fixed parameters is studied and a decrease in the transport following changes in the zonal flows is found.

  7. Electrically pumped edge-emitting photonic bandgap semiconductor laser

    DOE Patents [OSTI]

    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.

  8. Continuum kinetic modeling of the tokamak plasma edge

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dorf, M. A.; Dorr, M.; Rognlien, T.; Hittinger, J.; Cohen, R.

    2016-03-10

    In this study, the first 4D (axisymmetric) high-order continuum gyrokinetic transport simulations that span the magnetic separatrix of a tokamak are presented. The modeling is performed with the COGENT code, which is distinguished by fourth-order finite-volume discretization combined with mapped multiblock grid technology to handle the strong anisotropy of plasmatransport and the complex X-point divertor geometry with high accuracy. The calculations take into account the effects of fully nonlinear Fokker-Plank collisions, electrostatic potential variations, and anomalous radial transport. Topics discussed include: (a) ion orbit loss and the associated toroidal rotation and (b) edge plasma relaxation in the presence of anomalousmore » radial transport.« less

  9. Magnetic edge states in Aharonov-Bohm graphene quantum rings

    SciTech Connect (OSTI)

    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.

  10. Conductance matrix of multiterminal semiconductor devices with edge channels

    SciTech Connect (OSTI)

    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.

  11. Center for Plasma Edge Simulation (CPES): Final Technical Report

    SciTech Connect (OSTI)

    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 Energy?¢????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.

  12. Microsoft PowerPoint - Aeroacoustics_Berg_JRZA2.ppt

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of simple trailing edge treatment * Challenges: - Large separation on blunt trailing ... other advanced structural concepts in wind turbine blades * Objective: build stronger, ...

  13. Simultaneous laser cutting and welding of metal foil to edge of a plate

    DOE Patents [OSTI]

    Pernicka, John C.; Benson, David K.; Tracy, C. Edwin

    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.

  14. Simultaneous laser cutting and welding of metal foil to edge of a plate

    DOE Patents [OSTI]

    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.

  15. Tuning magnetic splitting of zigzag graphene nanoribbons by edge functionalization with hydroxyl groups

    SciTech Connect (OSTI)

    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.

  16. Research Led by Sandia Reveals Leading-Edge Erosion Significantly Reduces

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Wind Turbine Performance | Department of Energy Research Led by Sandia Reveals Leading-Edge Erosion Significantly Reduces Wind Turbine Performance Research Led by Sandia Reveals Leading-Edge Erosion Significantly Reduces Wind Turbine Performance January 6, 2014 - 10:00am Addthis This is an excerpt from the Fourth Quarter 2013 edition of the Wind Program R&D Newsletter. Research conducted by the U.S. Department of Energy's Sandia National Laboratories revealed that leading-edge erosion on

  17. © Marketing Edge Consulting Group and TargetGov Successful Marketing Tactics

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Marketing Edge Consulting Group and TargetGov Successful Marketing Tactics for Government Contracts Beth Goldstein Gloria Berthold Larkin © Marketing Edge Consulting Group and TargetGov Beth Goldstein * President, Sales & Marketing Consultant * Entrepreneurship Educator * Author and Trainer on Small Business Growth 2 © Marketing Edge Consulting Group and TargetGov Gloria Berthold Larkin * President * Federal Business Development expert, recently quoted in the Wall Street Journal and

  18. Gain media edge treatment to suppress amplified spontaneous emission in a high power laser

    DOE Patents [OSTI]

    Hackel, Lloyd A.; Soules, Thomas F.; Fochs, Scott N.; Rotter, Mark D.; Letts, Stephan A.

    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.

  19. Gain media edge treatment to suppress amplified spontaneous emission in a high power laser

    DOE Patents [OSTI]

    Hackel, Lloyd A.; Soules, Thomas F.; Fochs, Scott N.; Rotter, Mark D.; Letts, Stephan A.

    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.

  20. Edge transport studies in the edge and scrape-off layer of the National Spherical Torus Experiment with Langmuir probes

    SciTech Connect (OSTI)

    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 ?410{sup 21}?s{sup ?1} in L-mode and are suppressed to ?0.210{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 ?110{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.

  1. NREL Serves as the Energy Department's Showcase for Cutting-Edge...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Serves as the Energy Department's Showcase for Cutting-Edge Fuel Cell Cars Research Studies Fueling System, Driver Behavior, and Vehicle Performance January 25, 2016 The Energy ...

  2. Spin-transfer-torque efficiency enhanced by edge-damage of perpendicular magnetic random access memories

    SciTech Connect (OSTI)

    Song, Kyungmi; Lee, Kyung-Jin

    2015-08-07

    We numerically investigate the effect of magnetic and electrical damages at the edge of a perpendicular magnetic random access memory (MRAM) cell on the spin-transfer-torque (STT) efficiency that is defined by the ratio of thermal stability factor to switching current. We find that the switching mode of an edge-damaged cell is different from that of an undamaged cell, which results in a sizable reduction in the switching current. Together with a marginal reduction of the thermal stability factor of an edge-damaged cell, this feature makes the STT efficiency large. Our results suggest that a precise edge control is viable for the optimization of STT-MRAM.

  3. New 100Gbps Network Will Keep America on Cutting Edge of Innovation...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    New 100Gbps Network Will Keep America on Cutting Edge of Innovation November 15, 2011 - ... A new prototype network built by the Energy Department's Energy Sciences Network (ESnet), ...

  4. Particle size effect of hydride formation and surface hydrogen absorption of nanosized palladium catalysts : L{sub 3} edge vs K edge x-ray absorption spectroscopy.

    SciTech Connect (OSTI)

    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.

  5. Chevron beam dump for ITER edge Thomson scattering system

    SciTech Connect (OSTI)

    Yatsuka, E.; Hatae, T.; Bassan, M.; Itami, K.; Vayakis, G.

    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.

  6. Cutting-edge issues of core-collapse supernova theory

    SciTech Connect (OSTI)

    Kotake, Kei; Nakamura, Ko; Kuroda, Takami; Takiwaki, Tomoya

    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.

  7. Near edge X-ray absorption mass spectrometry on coronene

    SciTech Connect (OSTI)

    Reitsma, G.; Deuzeman, M. J.; Hoekstra, R.; Schlathölter, T.; Boschman, L.; Hoekstra, S.

    2015-01-14

    We have investigated the photoionization and photodissociation of free coronene cations C{sub 24}H{sub 12}{sup +} upon soft X-ray photoabsorption in the carbon K-edge region by means of a time-of-flight mass spectrometry approach. Core excitation into an unoccupied molecular orbital (below threshold) and core ionization into the continuum both leave a C 1s vacancy, that is subsequently filled in an Auger-type process. The resulting coronene dications and trications are internally excited and cool down predominantly by means of hydrogen emission. Density functional theory was employed to determine the dissociation energies for subsequent neutral hydrogen loss. A statistical cascade model incorporating these dissociation energies agrees well with the experimentally observed dehydrogenation. For double ionization, i.e., formation of intermediate C{sub 24}H{sub 12}{sup 3+⋆}trications, the experimental data hint at loss of H{sup +} ions. This asymmetric fission channel is associated with hot intermediates, whereas colder intermediates predominantly decay via neutral H loss.

  8. Nonlinear simulations of particle source effects on edge localized mode

    SciTech Connect (OSTI)

    Huang, J.; Tang, C. J.; Chen, S. Y.; Wang, Z. H.

    2015-12-15

    The effects of particle source (PS) with different intensities and located positions on Edge Localized Mode (ELM) are systematically studied with BOUT++ code. The results show the ELM size strongly decreases with increasing the PS intensity once the PS is located in the middle or bottom of the pedestal. The effects of PS on ELM depend on the located position of PS. When it is located at the top of the pedestal, peeling-ballooning (P-B) modes can extract more free energy from the pressure gradient and grow up to be a large filament at the initial crash phase and the broadening of mode spectrum can be suppressed by PS, which leads to more energy loss. When it is located in the middle or bottom of the pedestal, the extraction of free energy by P-B modes can be suppressed, and a small filament is generated. During the turbulence transport phase, the broader mode spectrum suppresses the turbulence transport when PS is located in the middle, while the zonal flow plays an important role in damping the turbulence transport when PS is located at the bottom.

  9. Public Forum: Laboratory trails

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Public Comment Opportunities Public Comment Opportunities Below are links to DOE NEPA projects with open comment periods, including comment periods on the proposed scope of planned NEPA documents and on draft NEPA documents (e.g., draft environmental assessments and draft environmental impacts statements). EIS-0527: Nationwide Public Safety Broadband Network Programmatic Environmental Impact Statement for the Central United States Public Comment Period Ends: 10/11/2016 The First Responder

  10. Joint spatio-spectral based edge detection for multispectral infrared imagery.

    SciTech Connect (OSTI)

    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.

  11. MODELING OF STOCHASTIC MAGNETIC FLUX LOSS FROM THE EDGE OF A POOIDALLY DIVERTED TOKAMAK

    SciTech Connect (OSTI)

    EVANS, TE,; MOYER, RA; MONAT, P

    2002-06-01

    OAK A271 MODELING OF STOCHASTIC MAGNETIC FLUX LOSS FROM THE EDGE OF A POOIDALLY DIVERTED TOKAMAK. A field line integration code is used to study the loss of edge poloidal magnetic flux due to stochastic magnetic fields produced by an error field correction coil (C-coil) in DIII-D for various plasma shapes, coil currents and edge magnetic shear profiles. The authors find that the boundary of a diverted tokamak is more sensitive to stochastic flux loss than a nondiverted tokamak. The C-coil has been used to produce a stochastic layer in an ohmic diverted discharge with characteristics similar to those seen in stochastic boundary experiments in circular limiter ohmic plasmas, including: (1) an overall increase in recycling, (2) a broadening of the recycling profile at the divertor, and (3) a flattening of the boundary profiles over the extent of the stochastic layer predicted by the field line integration code. Profile flattening consistent with field line integration results is also seen in some high performance discharges with edge transport barriers. The prediction of a significant edge stochastic layer even in discharges with high performance and edge radial transport barriers indicates that either the self-consistent plasma response heals the stochastic layer or that edge stochastic layers are compatible with edge radial transport barriers.

  12. Edge localized mode characteristics during edge localized mode mitigation by supersonic molecular beam injection in Korea Superconducting Tokamak Advanced Research

    SciTech Connect (OSTI)

    Lee, H. Y.; Hong, J. H.; Jang, J. H.; Park, J. S.; Choe, Wonho; Hahn, S. H.; Bak, J. G.; Lee, J. H.; Ko, W. H.; Lee, K. D.; Lee, S. H.; Lee, H. H.; Juhn, J.-W.; Kim, H. S.; Yoon, S. W.; Han, H.; Ghim, Y.-C.

    2015-12-15

    It has been reported that supersonic molecular beam injection (SMBI) is an effective means of edge localized mode (ELM) mitigation. This paper newly reports the changes in the ELM, plasma profiles, and fluctuation characteristics during ELM mitigation by SMBI in Korea Superconducting Tokamak Advanced Research. During the mitigated ELM phase, the ELM frequency increased by a factor of 2–3 and the ELM size, which was estimated from the D{sub α} amplitude, the fractional changes in the plasma-stored energy and the line-averaged electron density, and divertor heat flux during an ELM burst, decreased by a factor of 0.34–0.43. Reductions in the electron and ion temperatures rather than in the electron density were observed during the mitigated ELM phase. In the natural ELM phase, frequency chirping of the plasma fluctuations was observed before the ELM bursts; however, the ELM bursts occurred without changes in the plasma fluctuation frequency in the mitigated ELM phase.

  13. Framework Application for Core Edge Transport Simulation (FACETS)

    SciTech Connect (OSTI)

    Dr. Allen D. Malony; Dr. Sameer S. Shende; Dr. Kevin A. Huck; Mr. Alan Morris, and Mr. Wyatt Spear

    2012-03-14

    The goal of the FACETS project (Framework Application for Core-Edge Transport Simulations) was to provide a multiphysics, parallel framework application (FACETS) that will enable whole-device modeling for the U.S. fusion program, to provide the modeling infrastructure needed for ITER, the next step fusion confinement device. Through use of modern computational methods, including component technology and object oriented design, FACETS is able to switch from one model to another for a given aspect of the physics in a flexible manner. This enables use of simplified models for rapid turnaround or high-fidelity models that can take advantage of the largest supercomputer hardware. FACETS does so in a heterogeneous parallel context, where different parts of the application execute in parallel by utilizing task farming, domain decomposition, and/or pipelining as needed and applicable. ParaTools, Inc. was tasked with supporting the performance analysis and tuning of the FACETS components and framework in order to achieve the parallel scaling goals of the project. The TAU Performance System® was used for instrumentation, measurement, archiving, and profile / tracing analysis. ParaTools, Inc. also assisted in FACETS performance engineering efforts. Through the use of the TAU Performance System, ParaTools provided instrumentation, measurement, analysis and archival support for the FACETS project. Performance optimization of key components has yielded significant performance speedups. TAU was integrated into the FACETS build for both the full coupled application and the UEDGE component. The performance database provided archival storage of the performance regression testing data generated by the project, and helped to track improvements in the software development.

  14. Microcutting characteristics on the single crystal diamond tool with edge radius using molecular dynamics

    SciTech Connect (OSTI)

    Kim, Jeong-Du; Moon, Chan-Hong

    1995-12-31

    Ultraprecision metal cutting (UPMC) technology which makes possible submicrometer form accuracy and manometer roughness is developed to reach the 1nm nominal (undeformed) thickness of cut. At this thickness level, a few of atom`s layers should be considered. In this paper using the Molecuar Dynamics simulation, the phenomena of microcutting with a subnanometer chip thickness, the cutting mechanism for tool edge configuration to consider the sharp edge and round edge tool, the cut material and cutting speed are evaluated. Cutting mechanism of subnanometer depth of cut is evaluated.

  15. Shape and edge dependent electronic and magnetic properties of silicene nano-flakes

    SciTech Connect (OSTI)

    Mohan, Brij Pooja,; Ahluwalia, P. K.; Kumar, Ashok

    2015-06-24

    We performed first-principle study of the geometric, electronic and magnetic properties of arm-chair and zigzag edge silicene nano-flakes of triangular and hexagonal shapes. Electronic properties of silicene nano-flakes show strong dependence on their edge structure and shape. The considered nanostructures shows energy gap ranging ∼ 0.4 – 1.0 eV. Zigzag edged triangular nano-flake is magnetic and semiconducting in nature with 4.0 µ{sub B} magnetic moment and ∼ 0.4 eV energy gap.

  16. Plasma Flow in MST: Effects of Edge Biasing and Momentum Transport

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Flow in MST: Effects of Edge Biasing and Momentum Transport from Nonlinear Magnetic Torques J.S. Sarff, A.F. Almagri, J.K. Anderson, B.E. Chapman, D. Craig, C-S. Chiang, N.A. Crocker, D.J. Den Hartog, G. Fiksel, A.K. Hansen, and S.C. Prager Physics Department, University of Wisconsin Madison, Wisconsin, 53706 U.S.A Edge biasing in MST plasmas decreases electrostatic turbulent particle transport and increases the global particle confinement time. New Langmuir probe measurements in the edge

  17. A Reanalysis of Curvature in the Dose Response for Cancer and Modifications by Age at Exposure Following Radiation Therapy for Benign Disease

    SciTech Connect (OSTI)

    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.

  18. © Marketing Edge Consulting Group and TargetGov Successful Marketing...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    ... officer and program manager the same * Don't use AOL, gmail, Verizon or similar emails * Don't expect miracles 34 Marketing Edge Consulting Group and TargetGov ...

  19. Progress with the COGENT Edge Kinetic Code: Implementing the Fokker-Plank Collision Operator

    SciTech Connect (OSTI)

    Dorf, M. A.; Cohen, R. H.; Dorr, M.; Hittinger, J.; Rognlien, T. D.

    2014-06-20

    Here, COGENT is a continuum gyrokinetic code for edge plasma simulations being developed by the Edge Simulation Laboratory collaboration. The code is distinguished by application of a fourth-order finite-volume (conservative) discretization, and mapped multiblock grid technology to handle the geometric complexity of the tokamak edge. The distribution function F is discretized in v∥ – μ (parallel velocity – magnetic moment) velocity coordinates, and the code presently solves an axisymmetric full-f gyro-kinetic equation coupled to the long-wavelength limit of the gyro-Poisson equation. COGENT capabilities are extended by implementing the fully nonlinear Fokker-Plank operator to model Coulomb collisions in magnetized edge plasmas. The corresponding Rosenbluth potentials are computed by making use of a finite-difference scheme and multipole-expansion boundary conditions. Details of the numerical algorithms and results of the initial verification studies are discussed. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

  20. Edge-channel interferometer at the graphene quantum Hall pn junction

    SciTech Connect (OSTI)

    Morikawa, Sei; Moriya, Rai; Masubuchi, Satoru Machida, Tomoki; Watanabe, Kenji; Taniguchi, Takashi

    2015-05-04

    We demonstrate a quantum Hall edge-channel interferometer in a high-quality graphene pn junction under a high magnetic field. The co-propagating p and n quantum Hall edge channels traveling along the pn interface functions as a built-in Aharonov-Bohm-type interferometer, the interferences in which are sensitive to both the external magnetic field and the carrier concentration. The trajectories of peak and dip in the observed resistance oscillation are well reproduced by our numerical calculation that assumes magnetic flux quantization in the area enclosed by the co-propagating edge channels. Coherent nature of the co-propagating edge channels is confirmed by the checkerboard-like pattern in the dc-bias and magnetic-field dependences of the resistance oscillations.

  1. PISCES Program: Plasma-materials interactions and edge-plasma physics research

    SciTech Connect (OSTI)

    Conn, R.W.; Hirooka, Y.

    1992-07-01

    This program investigates and characterizes the behavior of materials under plasma bombordment, in divertor regions. The PISCES facility is used to study divertor and plasma edge management concepts (in particular gas target divertors), as well as edge plasma turbulence and transport. The plasma source consists of a hot LaB[sub 6] cathode with an annular, water-cooled anode and attached drift tube. This cross sectional area of the plasma can be adjusted between 3 and 10 cm. A fast scanning diagnostic probe system was used for mapping plasma density profiles during biased limiter and divertor simulation experiments. Some experimental data are given on: (1) materials and surface physics, (2) edge plasma physics, and (3) a theoretical analysis of edge plasma modelling.

  2. IBEX satellite finds ribbon-like structure at edge of heliosphere

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    IBEX satellite finds ribbon-like structure at edge of heliosphere The NASA IBEX mission ... Using the High Energy Neutral Atom Imager, led by Los Alamos National Laboratory, the NASA ...

  3. UCLA program in theory and modeling of edge physics and plasma material interaction

    SciTech Connect (OSTI)

    Conn, R.W.; Najmabadi, F.; Grossman, A.; Merriman, B.; Day, M.

    1992-01-01

    Our research activity in edge plasma modeling is directed towards understanding edge plasma behavior and towards innovative solutions for controlling the edge plasma as well as the design and operation of impurity control, particle exhaust. and plasma facing components. During the last nine months, substantial progress was made in many areas. The highlights are: (A) Development of a second-generation edge-plasma simulation code (Section II); (B) Development of models for gas-target divertors, including a 1[1/2]-D fluid model for plasma and Monte Carlo neutral-transport simulations (Section III); and (C) Utilization of the RF ponderomotive force and electrostatic biasing to distribute the heat load on a larger area of the divertor plate, and the development of analytical and numerical transport models that include both ponderomotive and electrostatic potentials.

  4. Electric field control of spin-resolved edge states in graphene quantum nanorings

    SciTech Connect (OSTI)

    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.

  5. 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,...

  6. New Energy Star Initiative Recognizes Cutting-Edge Products with Highest

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Energy Efficiency | Department of Energy Star Initiative Recognizes Cutting-Edge Products with Highest Energy Efficiency New Energy Star Initiative Recognizes Cutting-Edge Products with Highest Energy Efficiency July 14, 2011 - 12:00am Addthis WASHINGTON - The U.S. Environmental Protection Agency (EPA) and U.S. Department of Energy (DOE) today are announcing for the first time products recognized as the most energy-efficient in their categories among those that have earned the Energy Star

  7. SunShot Awardee 1366 Technologies Turns Cutting-Edge Research into

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Manufacturing Success | Department of Energy Awardee 1366 Technologies Turns Cutting-Edge Research into Manufacturing Success SunShot Awardee 1366 Technologies Turns Cutting-Edge Research into Manufacturing Success October 14, 2015 - 2:42pm Addthis 1366 Technician Becky Allen works in a lab at the company’s Bedford, MA demonstration facility. | Photo courtesy of Bob Frechette 1366 Technician Becky Allen works in a lab at the company's Bedford, MA demonstration facility. | Photo courtesy

  8. U.S. Department of Energy and Masdar Collaborate In Testing Cutting-Edge

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Solar PV Coating Technologies | Department of Energy Masdar Collaborate In Testing Cutting-Edge Solar PV Coating Technologies U.S. Department of Energy and Masdar Collaborate In Testing Cutting-Edge Solar PV Coating Technologies February 28, 2011 - 12:00am Addthis Abu Dhabi-UAE: The U.S. Department of Energy (DOE) and Masdar, Abu Dhabi's multifaceted renewable energy initiative, announced that they will collaborate to test the performance of specially coated solar photovoltaic modules

  9. Dynamics and generation mechanisms of mesoscale structures in tokamak edge plasmas

    SciTech Connect (OSTI)

    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.

  10. Longfellow Middle School Edges Out Gildersleeve to Win 2011 Virginia Middle

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    School Science Bowl | Jefferson Lab Edges Out Gildersleeve to Win 2011 Virginia Middle School Science Bowl Longfellow Middle School Edges Out Gildersleeve to Win 2011 Virginia Middle School Science Bowl 1st_place_Longfellow.jpg The team from Longfellow Middle School, Falls Church, won the 2011 Virginia Regional Middle School Science Bowl held March 5 at Jefferson Lab. Pictured, left to right, are Ryan Golant, Kunal Naik, Keaton Lee, Tarun Kamath, Ross Dempsey and Coach James Bradford. Photo:

  11. Final Technical Report: Global Field Aligned Mesh and Gyrokinetic Field Solver in a Tokamak Edge Geometry

    SciTech Connect (OSTI)

    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.

  12. Secretary Chu Announces New Investments in Cutting-Edge Wind Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Research Facilities | Department of Energy Investments in Cutting-Edge Wind Energy Research Facilities Secretary Chu Announces New Investments in Cutting-Edge Wind Energy Research Facilities October 15, 2009 - 12:00am Addthis Washington, DC - U.S. Energy Secretary Steven Chu announced new investments today in three university-led wind energy research facilities that will enhance the United States' leadership role in testing and producing the most advanced and efficient wind turbines in the

  13. Small Businesses Nationwide Begin Work on Cutting-Edge Innovative Research

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Projects | Department of Energy Nationwide Begin Work on Cutting-Edge Innovative Research Projects Small Businesses Nationwide Begin Work on Cutting-Edge Innovative Research Projects February 21, 2012 - 12:18pm Addthis Washington, D.C. - Energy Secretary Steven Chu today announced that with support from the Department of Energy, 142 small businesses around the nation are starting work this week on 180 innovative research projects ranging from designing better wind turbines to developing a

  14. EERE Success Story-California: Cutting-Edge Biofuels Research and

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Entrepreneurship Provide a Proving Ground | Department of Energy Cutting-Edge Biofuels Research and Entrepreneurship Provide a Proving Ground EERE Success Story-California: Cutting-Edge Biofuels Research and Entrepreneurship Provide a Proving Ground April 18, 2013 - 12:00am Addthis The Advanced Biofuels Process Demonstration Unit (ABPDU) at DOE's Lawrence Berkeley National Laboratory provides state-of-the-art facilities for advanced biofuels and bioproducts production to create efficient

  15. DOE Awards Supercomputer Access to Cutting-Edge Projects | Department of

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Energy Supercomputer Access to Cutting-Edge Projects DOE Awards Supercomputer Access to Cutting-Edge Projects December 18, 2008 - 8:51am Addthis WASHINGTON, D.C. - The U.S. Department of Energy's (DOE) Office of Science announced today that 66 projects addressing some of the greatest scientific challenges have been awarded access to some of the world's most powerful supercomputers at DOE national laboratories. The projects-competitively selected for their technical readiness and scientific

  16. Beyond Pluto: The Search for the Edge of the Solar System focus of upcoming

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Frontiers in Science lectures Frontiers in Science lectures Beyond Pluto: The Search for the Edge of the Solar System focus of upcoming Frontiers in Science lectures Herb Funsten will explore the edge of the solar system and anticipate its future as it moves through our galactic neighborhood. July 30, 2015 IBEX spacecraft. Photo courtesy of NASA IBEX spacecraft. Photo courtesy of NASA Contact Los Alamos National Laboratory Steve Sandoval Communications Office (505) 665-9206 Email "In

  17. Salient issues of edge physics pertaining to loss of confinement: A resistive MHD analysis

    SciTech Connect (OSTI)

    Thayer, D.R.

    1991-01-01

    The progress that has been made during this fiscal year is significant in the area of tokamak edge plasma transport. The drift-rippling mode model of edge turbulent transport was extended. In particular, the research areas on which were concentrated include the following topics: (1) The theoretical investigation of the radiatively enhanced transport due to the effects of impurity driven radiation instabilities has been expanded to include a situation with multiple impurities (such as carbon, C{sup 4+}, and oxygen, O{sup 6+}); (2) In order to validate the use of the impurity radiation input from the tokamak bolometer experiments in the theoretical edge turbulent transport calculations, the analysis that is utilized to transform impurity brightness data to radiated power profiles has been checked for state population and Abel inversion correctness; (3) The drift-rippling model of edge turbulent transport has been extended to include ionization particle sources in addition to the impurity driven thermal instability drive; and (4) The detailed limiter and realistic edge geometric effects on the edge turbulent transport has been included in the drift-rippling model.

  18. Control volume finite element method with multidimensional edge element Scharfetter-Gummel upwinding. Part 1, formulation.

    SciTech Connect (OSTI)

    Bochev, Pavel Blagoveston

    2011-06-01

    We develop a new formulation of the Control Volume Finite Element Method (CVFEM) with a multidimensional Scharfetter-Gummel (SG) upwinding for the drift-diffusion equations. The formulation uses standard nodal elements for the concentrations and expands the flux in terms of the lowest-order Nedelec H(curl; {Omega})-compatible finite element basis. The SG formula is applied to the edges of the elements to express the Nedelec element degree of freedom on this edge in terms of the nodal degrees of freedom associated with the endpoints of the edge. The resulting upwind flux incorporates the upwind effects from all edges and is defined at the interior of the element. This allows for accurate evaluation of integrals on the boundaries of the control volumes for arbitrary quadrilateral elements. The new formulation admits efficient implementation through a standard loop over the elements in the mesh followed by loops over the element nodes (associated with control volume fractions in the element) and element edges (associated with flux degrees of freedom). The quantities required for the SG formula can be precomputed and stored for each edge in the mesh for additional efficiency gains. For clarity the details are presented for two-dimensional quadrilateral grids. Extension to other element shapes and three dimensions is straightforward.

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

    SciTech Connect (OSTI)

    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.

  20. On the low carrier lifetime edge zone in multicrystalline silicon ingots

    SciTech Connect (OSTI)

    Jiang, Tingting; Yu, Xuegong; Wang, Lei; Gu, Xin; Yang, Deren

    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.

  1. Unexpected edge conduction in mercury telluride quantum wells under broken time-reversal symmetry

    SciTech Connect (OSTI)

    Ma, Eric Yue; Calvo, M. Reyes; Wang, Jing; Lian, Biao; Muhlbauer, Mathias; Brune, Christoph; Cui, Yong -Tao; Lai, Keji; Kundhikanjana, Worasom; Yang, Yongliang; Baenninger, Matthias; Konig, Markus; Ames, Christopher; Buhmann, Hartmut; Leubner, Philipp; Molenkamp, Laurens W.; Zhang, Shou -Cheng; Goldhaber-Gordon, David; Kelly, Michael A.; Shen, Zhi -Xun

    2015-05-26

    The realization of quantum spin Hall effect in HgTe quantum wells is considered a milestone in the discovery of topological insulators. Quantum spin Hall states are predicted to allow current flow at the edges of an insulating bulk, as demonstrated in various experiments. A key prediction yet to be experimentally verified is the breakdown of the edge conduction under broken time-reversal symmetry. Here we first establish a systematic framework for the magnetic field dependence of electrostatically gated quantum spin Hall devices. We then study edge conduction of an inverted quantum well device under broken time-reversal symmetry using microwave impedance microscopy, and compare our findings to a non-inverted device. At zero magnetic field, only the inverted device shows clear edge conduction in its local conductivity profile, consistent with theory. Surprisingly, the edge conduction persists up to 9 T with little change. Finally, this indicates physics beyond simple quantum spin Hall model, including material-specific properties and possibly many-body effects.

  2. Unexpected edge conduction in mercury telluride quantum wells under broken time-reversal symmetry

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ma, Eric Yue; Calvo, M. Reyes; Wang, Jing; Lian, Biao; Muhlbauer, Mathias; Brune, Christoph; Cui, Yong -Tao; Lai, Keji; Kundhikanjana, Worasom; Yang, Yongliang; et al

    2015-05-26

    The realization of quantum spin Hall effect in HgTe quantum wells is considered a milestone in the discovery of topological insulators. Quantum spin Hall states are predicted to allow current flow at the edges of an insulating bulk, as demonstrated in various experiments. A key prediction yet to be experimentally verified is the breakdown of the edge conduction under broken time-reversal symmetry. Here we first establish a systematic framework for the magnetic field dependence of electrostatically gated quantum spin Hall devices. We then study edge conduction of an inverted quantum well device under broken time-reversal symmetry using microwave impedance microscopy,more » and compare our findings to a non-inverted device. At zero magnetic field, only the inverted device shows clear edge conduction in its local conductivity profile, consistent with theory. Surprisingly, the edge conduction persists up to 9 T with little change. Finally, this indicates physics beyond simple quantum spin Hall model, including material-specific properties and possibly many-body effects.« less

  3. Nitrogen K-edge X-ray absorption near edge structure (XANES) spectra of purine-containing nucleotides in aqueous solution

    SciTech Connect (OSTI)

    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 π* 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.

  4. X-ray K-edge analysis of drain lines in Wilhelm Hall, Ames Laboratory

    SciTech Connect (OSTI)

    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.

  5. Atomic friction at exposed and buried graphite step edges: Experiments and simulations

    SciTech Connect (OSTI)

    Ye, Zhijiang; Martini, Ashlie

    2015-06-08

    The surfaces of layered materials such as graphite exhibit step edges that affect friction. Step edges can be exposed, where the step occurs at the outmost layer, or buried, where the step is underneath another layer of material. Here, we study friction at exposed and buried step edges on graphite using an atomic force microscope (AFM) and complementary molecular dynamics simulations of the AFM tip apex. Exposed and buried steps exhibit distinct friction behavior, and the friction on either step is affected by the direction of sliding, i.e., moving up or down the step, and the bluntness of the tip. These trends are analyzing in terms of the trajectory of the AFM tip as it moves over the step, which is a convolution of the topography of the surface and the tip shape.

  6. The effect of spin-orbit coupling in band structure and edge states of bilayer graphene

    SciTech Connect (OSTI)

    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.

  7. Oxidation of step edges on vicinal 4H-SiC(0001) surfaces

    SciTech Connect (OSTI)

    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.

  8. DOE Awards Supercomputer Access to Cutting-Edge Projects | U.S. DOE Office

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of Science (SC) DOE Awards Supercomputer Access to Cutting-Edge Projects News News Home Featured Articles Science Headlines 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 Science Highlights Presentations & Testimony News Archives Communications and Public Affairs Contact Information Office of Science U.S. Department of Energy 1000 Independence Ave., SW Washington, DC 20585 P: (202) 586-5430 12.18.08 DOE Awards Supercomputer Access to Cutting-Edge Projects Print Text Size: A

  9. Ablation of high-Z material dust grains in edge plasmas of magnetic fusion devices

    SciTech Connect (OSTI)

    Marenkov, E. D.; Krasheninnikov, S. I.

    2014-12-15

    The model, including shielding effects of high-Z dust grain ablation in tokamak edge plasma, is presented. In a contrast to shielding models developed for pellets ablation in a hot plasma core, this model deals with the dust grain ablation in relatively cold edge plasma. Using some simplifications, a closed set of equations determining the grain ablation rate Γ is derived and analyzed both analytically and numerically. The scaling law for Γ versus grain radius and ambient plasma parameters is obtained and confirmed by the results of numerical solutions. The results obtained are compared with both dust grain models containing no shielding effects and the pellet ablation models.

  10. Study on higher harmonic suppression using edge filter and polished Si wafer

    SciTech Connect (OSTI)

    Gupta, R. K. Singh, Amol Modi, Mohammed H. Lodha, G. S.

    2014-04-24

    Higher harmonics contamination is a severe problem in synchrotron beamlines where grating monochromators are used. In these beamlines, absorption edge filters and critical angle mirrors are used to suppress the harmonic contaminations. In the present study, carried out using Indus-1 reflectivity beamline, a harmonic suppression characteristic of Al edge filter and polished silicon wafer are determined. It is found that the Al filter suppresses higher harmonics in 2–7% range whereas the polished silicon wafer can suppress the higher harmonics below 1%. The results of comparative study are discussed.

  11. Using LGI experiments to achieve better understanding of pedestal-edge coupling in NSTX-U

    SciTech Connect (OSTI)

    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.

  12. Solar Startup Semprius to Create 250 Jobs in North Carolina at Cutting-Edge

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Pilot Plant | Department of Energy Startup Semprius to Create 250 Jobs in North Carolina at Cutting-Edge Pilot Plant Solar Startup Semprius to Create 250 Jobs in North Carolina at Cutting-Edge Pilot Plant July 25, 2011 - 9:44am Addthis A tiny Semprius HCPV cell, mounted on an interposer. Each cell is only 0.6mm on one side. | Photo courtesy of Semprius A tiny Semprius HCPV cell, mounted on an interposer. Each cell is only 0.6mm on one side. | Photo courtesy of Semprius A prototype of the

  13. EM Launches Revamped Website: New cutting-edge platform with sleek

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    appearance focuses on ease-of-use | Department of Energy Launches Revamped Website: New cutting-edge platform with sleek appearance focuses on ease-of-use EM Launches Revamped Website: New cutting-edge platform with sleek appearance focuses on ease-of-use January 7, 2013 - 12:00pm Addthis A screenshot of the newly revamped EM website. A screenshot of the newly revamped EM website. EM's previous website EM's previous website A screenshot of the newly revamped EM website. EM's previous website

  14. TEMPEST Simulations of Collisionless Damping of Geodesic-Acoustic Mode in Edge Plasma Pedestal

    SciTech Connect (OSTI)

    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.

  15. Cutting-Edge Science Drives SunShot Projects | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Cutting-Edge Science Drives SunShot Projects Cutting-Edge Science Drives SunShot Projects August 4, 2016 - 9:45am Addthis Giant Leap Technologies uses microfluidics to bend light toward a solar at the top of the plant. Each solar thermal power plant shown is a football field in size. | <em>Photo courtesy of Giant Leap Technologies</em> Giant Leap Technologies uses microfluidics to bend light toward a solar at the top of the plant. Each solar thermal power plant shown is a football

  16. D.C. Showcases Cutting-Edge Hydrogen Fueling Station Demo | Department of

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Energy D.C. Showcases Cutting-Edge Hydrogen Fueling Station Demo D.C. Showcases Cutting-Edge Hydrogen Fueling Station Demo July 11, 2016 - 2:30pm Addthis Acting Assistant Secretary for Energy Efficiency and Renewable Energy David Friedman speaks at the opening of a hydrogen fueling technology demonstration station in Washington, D.C. | Photos by Mike Mueller/The Hannon Group Acting Assistant Secretary for Energy Efficiency and Renewable Energy David Friedman speaks at the opening of a

  17. Final Report for "Extending BOUT++ for Solution of Edge Plasma Equations for Use in Whole Device Simulation of Tokamaks"

    SciTech Connect (OSTI)

    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.

  18. Critical gradients and plasma flows in the edge plasma of Alcator C-Mod

    SciTech Connect (OSTI)

    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.

  19. Salient issues of edge physics pertaining to loss of confinement: A resistive MHD analysis

    SciTech Connect (OSTI)

    Thayer, D.R.

    1991-01-01

    The progress that has been made during this fiscal year is significant in the area of tokamak edge plasma transport. Important contributions on the extension of the drift-rippling mode model ([approximately] [tau], [approximately]n, [approximately]T, [approximately][nu][sub [parallel

  20. Transition-edge sensor with enhanced electrothermal feedback for cryogenic particle detection

    DOE Patents [OSTI]

    Nam, Sae Woo; Cabrera, Blas

    2001-01-01

    A superconducting transition-edge sensor with an electrothermal-feedback circuit, a heat sink thermally coupled thereto, a bias-feedback circuit electrically coupled with the electrothermal feedback circuit, and a current sensor electrically coupled with the bias-feedback circuit and inductively coupled with the electrothermal-feedback circuit.

  1. Progress with the COGENT Edge Kinetic Code: Implementing the Fokker-Plank Collision Operator

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dorf, M. A.; Cohen, R. H.; Dorr, M.; Hittinger, J.; Rognlien, T. D.

    2014-06-20

    Here, COGENT is a continuum gyrokinetic code for edge plasma simulations being developed by the Edge Simulation Laboratory collaboration. The code is distinguished by application of a fourth-order finite-volume (conservative) discretization, and mapped multiblock grid technology to handle the geometric complexity of the tokamak edge. The distribution function F is discretized in v∥ – μ (parallel velocity – magnetic moment) velocity coordinates, and the code presently solves an axisymmetric full-f gyro-kinetic equation coupled to the long-wavelength limit of the gyro-Poisson equation. COGENT capabilities are extended by implementing the fully nonlinear Fokker-Plank operator to model Coulomb collisions in magnetized edge plasmas.more » The corresponding Rosenbluth potentials are computed by making use of a finite-difference scheme and multipole-expansion boundary conditions. Details of the numerical algorithms and results of the initial verification studies are discussed. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)« less

  2. Bottom fixed OTEC plant on the edge of a continental (or island) shelf

    SciTech Connect (OSTI)

    Daidola, J.C.; Basar, N.; Sasscer, D.S.

    1981-01-01

    Consideration is given to a generic type of OTEC plant. This shallow water bottom fixed OTEC plant consists of a platform structure rigidly attached to the seabed at the edge of a continental or island shelf. A cost comparison and thoughts on commercialization are presented. Conclusions and recommendations indicate the desire and need for further development. 12 refs.

  3. Investigation of ELM [edge localized mode] Dynamics with the Resonant Magnetic Perturbation Effects

    SciTech Connect (OSTI)

    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.

  4. The d-edge shortest-path problem for a Monge graph

    SciTech Connect (OSTI)

    Bein, W.W.; Larmore, L.L.; Park, J.K.

    1992-07-14

    A complete edge-weighted directed graph on vertices 1,2,...,n that assigns cost c(i,j) to the edge (i,j) is called Monge if its edge costs form a Monge array, i.e., for all i < k and j < l, c[i, j]+c[k,l]{le} < c[i,l]+c[k,j]. One reason Monge graphs are interesting is that shortest paths can be computed quite quickly in such graphs. In particular, Wilber showed that the shortest path from vertex 1 to vertex n of a Monge graph can be computed in O(n) time, and Aggarwal, Klawe, Moran, Shor, and Wilber showed that the shortest d-edge 1-to-n path (i.e., the shortest path among all 1-to-n paths with exactly d edges) can be computed in O(dn) time. This paper`s contribution is a new algorithm for the latter problem. Assuming 0 {le} c[i,j] {le} U and c[i,j + 1] + c[i + 1,j] {minus} c[i,j] {minus} c[i + 1, j + 1] {ge} L > 0 for all i and j, our algorithm runs in O(n(1 + 1g(U/L))) time. Thus, when d {much_gt} 1 + 1g(U/L), our algorithm represents a significant improvement over Aggarwal et al.`s O(dn)-time algorithm. We also present several applications of our algorithm; they include length-limited Huffman coding, finding the maximum-perimeter d-gon inscribed in a given convex n-gon, and a digital-signal-compression problem.

  5. Gas turbine bucket wall thickness control

    DOE Patents [OSTI]

    Stathopoulos, Dimitrios; Xu, Liming; Lewis, Doyle C.

    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.

  6. Prediction of PFC Plasma Fluxes by Improved Edge/Scrape-off-layer Simulations

    SciTech Connect (OSTI)

    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

  7. Evaluation and calibration of a Los Alamos National Laboratory L/sub III/-edge densitometer

    SciTech Connect (OSTI)

    McGonnagle, W.J.; Holland, M.K.; Reynolds, C.S.; Trahey, N.M.; Zook, A.C.

    1983-07-01

    The Department of Energy (DOE), New Brunswick Laboratory (NBL) has evaluated and calibrated an L/sub III/-edge densitometer for the Los Alamos National Laboratory. This prototype instrument was designed for nondestructive on-line measurement of uranium and/or plutonium solutions. The sensitivity was optimized for measuring the uranium and plutonium concentrations in mixed solutions typical of those produced by solvent extraction in the U-Pu fuel cycle. Foil assays were performed on a daily basis to monitor the measurement precision and the stability of the calibration. Traceable reference solutions prepared at NBL were used to calibrate and evaluate the system. For solutions containing approximately 50 grams of uranium and/or plutonium per liter, the relative standard deviation for the L-edge measurements was approximately 0.3%. This experimental evaluation demonstrated that the solution matrix did not influence the results. The instrument performance in a laboratory environment was excellent.

  8. Fast Thermal Helium Beam diagnostic for measurements of edge electron profiles and fluctuations

    SciTech Connect (OSTI)

    Agostini, M. Scarin, P.; Cavazzana, R.; Carraro, L.; Grando, L.; Taliercio, C.; Franchin, L.; Tiso, A.

    2015-12-15

    The edge of fusion experiments is a region where strong gradients develop, together with the presence of strong fluctuations due to turbulence. The thermal helium beam diagnostic developed for the RFX-mod experiment allows the measurements with a single diagnostic of both low frequency time evolution of the edge radial profiles of electron density and temperature (tens of hertz), and the high frequency fluctuations (hundreds of kHz). To maximize the collected light, the three HeI lines necessary to be measured for the evaluation of n{sub e} and T{sub e} are separated with a spectrograph, and multianode photomultipliers are used as light detectors. The paper describes the diagnostic setup, with the interface hardware with the machine and the optical layout, and the characterization of its performances.

  9. A wall and edge guarded hot box for thermal transmittance measurements

    SciTech Connect (OSTI)

    Gatland, S.D. II; Miller, R.G.; Goss, W.P.; Baumgardner, R.L.; Williams, R.G.

    1997-11-01

    A unique guarded hot box designed for thermal testing of fenestration products incorporates several new design concepts from guarded hot plates, namely wall and edge guards, is described in detail. The wall and edge guarded hot box was built to meet the test methodologies specified in the American Society for Testing and Materials (ASTM) Standard Test Methods C 236-89, Standard Test Method for Measuring the Steady-State Thermal Performance of Building Assemblies by Means of a Guarded Hot Box, C 976-90, Standard Test Method for Measuring the Steady-State Thermal Performance of Building Assemblies by Means of a Calibrated Hot Box and C 1199-91, Standard Test Method for Measuring the Steady-State Thermal Transmittance of Fenestration Systems Using Hot Box Methods. Calibration test results for the box wall and specimen frame flanking are presented. Results from calibration transfer standard tests are compared with theoretical calculations and discussed.

  10. Effect of non-diffusive processes on transport and its interpretation in the tokamak plasma edge

    SciTech Connect (OSTI)

    Stacey, Weston M.

    2013-11-15

    An interpretive methodology improved to account for two non-diffusive transport mechanisms—particle pinch and ion orbit loss—was 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.

  11. SXR-XUV Diagnostics for Edge and Core of Magnetically Confined Plasmas

    SciTech Connect (OSTI)

    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.

  12. Generation of a magnetic island by edge turbulence in tokamak plasmas

    SciTech Connect (OSTI)

    Poy, A.; Agullo, O.; Muraglia, M.; Benkadda, S.; Dubuit, N.; Garbet, X.; Sen, A.

    2015-03-15

    We investigate, through extensive 3D magneto-hydro-dynamics numerical simulations, the nonlinear excitation of a large scale magnetic island and its dynamical properties due to the presence of small-scale turbulence. Turbulence is induced by a steep pressure gradient in the edge region [B. D. Scott, Plasma Phys. Controlled Fusion 49, S25 (2007)], close to the separatrix in tokamaks where there is an X-point magnetic configuration. We find that quasi-resonant localized interchange modes at the plasma edge can beat together and produce extended modes that transfer energy to the lowest order resonant surface in an inner stable zone and induce a seed magnetic island. The island width displays high frequency fluctuations that are associated with the fluctuating nature of the energy transfer process from the turbulence, while its mean size is controlled by the magnetic energy content of the turbulence.

  13. Stationary zonal flows during the formation of the edge transport barrier in the JET tokamak

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hillesheim, J. C.; Meyer, H.; Maggi, C. F.; Meneses, L.; Poli, E.; Delabie, E.

    2016-02-10

    In this study, high spatial resolution Doppler backscattering measurements in JET have enabled new insights into the development of the edge Er. We observe fine-scale spatial structures in the edge Er well with a wave number krρi ≈ 0.4-0.8, consistent with stationary zonal flows, the characteristics of which vary with density. The zonal flow amplitude and wavelength both decrease with local collisionality, such that the zonal flow E x B shear increases. Above the minimum of the L-H transition power threshold dependence on density, the zonal flows are present during L mode and disappear following the H-mode transition, while belowmore » the minimum they are reduced below measurable amplitude during L mode, before the L-H transition.« less

  14. NREL report shows E85 gives gas stations a competitive edge - News Releases

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    | NREL report shows E85 gives gas stations a competitive edge Quantity of E85 sold most important factor in profitability July 18, 2008 A study released by the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) can help gas station owners and Clean Cities stakeholders determine whether adding E85 to their product mix can increase profitability. Competition in the fueling station business continues to intensify, particularly as grocery stores and discount clubs

  15. PPPL scientists present cutting-edge results at major physics meeting |

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Princeton Plasma Physics Lab PPPL scientists present cutting-edge results at major physics meeting By Kitta MacPherson November 12, 2013 Tweet Widget Google Plus One Share on Facebook Gallery: The "Remote Glow Discharge Experiment (RGDX)". The "Remote Glow Discharge Experiment (RGDX)". Arturo Dominguez. (Photo by Elle Starkman/ PPPL Office of Communications) Arturo Dominguez. More than 1,500 researchers, including scientists from the U.S. Department of Energy's Princeton

  16. Edge seal for a porous gas distribution plate of a fuel cell

    DOE Patents [OSTI]

    Feigenbaum, Haim; Pudick, Sheldon; Singh, Rajindar

    1984-01-01

    In an improved seal for a gas distribution plate of a fuel cell, a groove is provided extending along an edge of the plate. A member of resinous material is arranged within the groove and a paste comprising an immobilized acid is arranged surrounding the member and substantially filling the groove. The seal, which is impervious to the gas being distributed, is resistant to deterioration by the electrolyte of the cell.

  17. Scattering of Radio Frequency Waves by Edge Density Blobs in Tokamak Plasmas

    SciTech Connect (OSTI)

    Ram, A. K.; Hizanidis, K.; Kominis, Y.

    2011-12-23

    The density blobs and fluctuations present in the edge region of magnetic fusion devices can scatter radio frequency (RF) waves through refraction and diffraction. The scattering can diffuse the rays in space and in wave-vector space. The diffusion in space can make the rays miss their intended target region, while the diffusion in wave-vector space can broaden the wave spectrum and modify the wave damping and current profile.

  18. Shot-noise at a Fermi-edge singularity: Non-Markovian dynamics

    SciTech Connect (OSTI)

    Ubbelohde, N.; Maire, N.; Haug, R. J.; Roszak, K.; Hohls, F.; Novotn, 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.

  19. Hot Rolling Scrap Reduction through Edge Cracking and Surface Defects Control

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Hot Rolling Scrap Reduction through Edge Cracking and Surface Defects Control Improving Energy Efficiency in Hot Rolling by Increasing Recovery Rates Hot rolling of large ingots is the predominant process for producing plate, sheet, and foil aluminum products. Hot rolling has typical recovery rates of 82%, because 18% of the original material is lost as planned end cuts and scalping, or as incidental (unplanned) scrap. Hot rolled scrap is then typically re-melted to either form fresh ingot

  20. Resonant-like behaviour during edge-localised mode cycles in the Joint European Torus

    SciTech Connect (OSTI)

    Webster, A. J.; Morris, J.; Todd, T. N.; Coad, P.; Brezinsek, S.; Likonen, J.; Rubel, M.; Collaboration: JET-EFDA Contributors

    2015-08-15

    A unique sequence of 120 almost identical plasmas in the Joint European Torus (JET) recently provided two orders of magnitude more statistically equivalent data than ever previously available. The purpose was to study movement of eroded plasma-facing material from JET's new Beryllium wall, but it has allowed the statistical detection of otherwise unobservable phenomenon. This includes a sequence of resonant-like waiting times between edge-localised plasma instabilities (ELMs), instabilities that must be mitigated or avoided in large magnetically confined plasmas such as those planned for ITER. Here, we investigate the cause of this phenomenon, using the unprecedented quantity of data to produce a detailed picture of the plasma's behaviour. After combining the data, oscillations are clearly observable in the plasma's vertical position, in edge losses of ions, and in Beryllium II (527 nm) light emissions. The oscillations are unexpected, are not obvious in data from a single pulse alone, and are all clearly correlated with each other. They are likely to be caused by a small vertical oscillation that the plasma control system is not reacting to prevent, but a more complex explanation is possible. The clearly observable but unexpected link between small changes in the plasma's position and changes to edge-plasma transport and stability suggest that these characteristics cannot always be studied in isolation. It also suggests new opportunities for ELM mitigation and control that may exist.

  1. Edge effects, not connectivity, determine the incidence and development of a foliar fungal plant disease.

    SciTech Connect (OSTI)

    Johnson, Brenda, L.; Haddad, Nick, M.

    2011-08-01

    Using a model plant-pathogen system in a large-scale habitat corridor experiment, we found that corridors do not facilitate the movement of wind-dispersed plant pathogens, that connectivity of patches does not enhance levels of foliar fungal plant disease, and that edge effects are the key drivers of plant disease dynamics. Increased spread of infectious disease is often cited as a potential negative effect of habitat corridors used in conservation, but the impacts of corridors on pathogen movement have never been tested empirically. Using sweet corn (Zea mays) and southern corn leaf blight (Cochliobolus heterostrophus) as a model plant-pathogen system, we tested the impacts of connectivity and habitat fragmentation on pathogen movement and disease development at the Savannah River Site, South Carolina, USA. Over time, less edgy patches had higher proportions of diseased plants, and distance of host plants to habitat edges was the greatest determinant of disease development. Variation in average daytime temperatures provided a possible mechanism for these disease patterns. Our results show that worries over the potentially harmful effects of conservation corridors on disease dynamics are misplaced, and that, in a conservation context, many diseases can be better managed by mitigating edge effects.

  2. Nonlinear excitation of low-n harmonics in reduced magnetohydrodynamic simulations of edge-localized modes

    SciTech Connect (OSTI)

    Krebs, I.; Hölzl, M.; Lackner, K.; Günter, S.

    2013-08-15

    Nonlinear simulations of the early edge-localized mode (ELM) phase based on a typical type-I ELMy ASDEX Upgrade discharge have been carried out using the reduced MHD code JOREK. The analysis is focused on the evolution of the toroidal Fourier spectrum. It is found that during the nonlinear evolution, linearly subdominant low-n Fourier components, in particular the n = 1, grow to energies comparable with linearly dominant harmonics. A simple model is developed, based on the idea that energy is transferred among the toroidal harmonics via second order nonlinear interaction. The simple model reproduces and explains very well the early nonlinear evolution of the toroidal spectrum in the JOREK simulations. Furthermore, it is shown for the n = 1 harmonic, that its spatial structure changes significantly during the transition from linear to nonlinearly driven growth. The rigidly growing structure of the linearly barely unstable n = 1 reaches far into the plasma core. In contrast, the nonlinearly driven n= 1 has a rigidly growing structure localized at the plasma edge, where the dominant toroidal harmonics driving the n = 1 are maximal and in phase. The presented quadratic coupling model might explain the recent experimental observation of strong low-n components in magnetic measurements [Wenninger et al., “Non-linear magnetic perturbations during edge localized modes in TCV dominated by low n mode components,” Nucl. Fusion (submitted)].

  3. Visualizing nanoscale excitonic relaxation properties of disordered edges and grain boundaries in monolayer molybdenum disulfide

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bao, Wei; Borys, Nicholas J.; Ko, Changhyun; Suh, Joonki; Fan, Wen; Thron, Andrew; Zhang, Yingjie; Buyanin, Alexander; Zhang, Jie; Cabrini, Stefano; et al

    2015-08-13

    The ideal building blocks for atomically thin, flexible optoelectronic and catalytic devices are two-dimensional monolayer transition metal dichalcogenide semiconductors. Although challenging for two-dimensional systems, sub-diffraction optical microscopy provides a nanoscale material understanding that is vital for optimizing their optoelectronic properties. We use the ‘Campanile’ nano-optical probe to spectroscopically image exciton recombination within monolayer MoS2 with sub-wavelength resolution (60 nm), at the length scale relevant to many critical optoelectronic processes. Moreover, synthetic monolayer MoS2 is found to be composed of two distinct optoelectronic regions: an interior, locally ordered but mesoscopically heterogeneous two-dimensional quantum well and an unexpected ~300-nm wide, energetically disorderedmore » edge region. Further, grain boundaries are imaged with sufficient resolution to quantify local exciton-quenching phenomena, and complimentary nano-Auger microscopy reveals that the optically defective grain boundary and edge regions are sulfur deficient. In conclusion, the nanoscale structure–property relationships established here are critical for the interpretation of edge- and boundary-related phenomena and the development of next-generation two-dimensional optoelectronic devices.« less

  4. The pinch of cold ions from recycling in the tokamak edge pedestal

    SciTech Connect (OSTI)

    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.

  5. Fully Nonlinear Edge Gyrokinetic Simulations of Kinetic Geodesic-Acoustic Modes and Boundary Flows

    SciTech Connect (OSTI)

    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.

  6. Automated on-line L-edge measurement of SNM concentration for near-real-time accounting

    SciTech Connect (OSTI)

    Russo, P.A.; Marks, T. Jr.; Stephens, M.M.; Hsue, S.T.; Baker, A.L.; Cobb, D.D.

    1982-01-01

    The L-edge densitometer developed at Los Alamos National Laboratory has been modified, tested, and demonstrated for on-line assay of special nuclear material concentration in flowing solution streams. The demonstration was part of a larger demonstration of near-real-time nuclear materials accounting during a continuous, week-long, cold operation of the Allied General Nuclear Services facility in Barnwell, South Carolina. The L-edge data were automatically analyzed and the results were transmitted to the materials accounting computer once every 5.5 min for the duration of the cold run. This report compares the results of the L-edge analyses with the delayed results obtained from destructive analysis of samples withdrawn from the same process line. Comparisons are also made with the results obtained in near real time from an automated process control instrument installed in series with the L-edge densitometer. The performance of the L-edge instrument was reliable throughout the continous operation. The assay precision was consistent with that predicted by the counting statistics of the measurement. The results of the L-edge assays show good agreement with those of the destructive assays. A gradually varying discrepancy (of a few percent) between the L-edge and the process control results remains unexplained. 9 figures.

  7. Magnetism induced by excess electrons trapped at diamagnetic edge-quantum well in multi-layer graphene

    SciTech Connect (OSTI)

    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.

  8. Disruption avoidance in the SINP-Tokamak by means of electrode-biasing at the plasma edge

    SciTech Connect (OSTI)

    Basu, Debjyoti; Pal, Rabindranath; Ghosh, Joydeep; Chattopadhyay, Prabal K.

    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.

  9. Temperature dependence of the Pd [ital K]-edge extended x-ray-absorption fine structure of PdC[sub [ital x

    SciTech Connect (OSTI)

    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

  10. Settler's Trail | Open Energy Information

    Open Energy Info (EERE)

    Developer E.ON Climate & Renewables North America Energy Purchaser Merchant Location Sheldon IL Coordinates 40.7626336, -87.54498482 Show Map Loading map......

  11. Access to a New Plasma Edge State with High Density and Pressures using Quiescent H-mode

    SciTech Connect (OSTI)

    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.

  12. Intrinsic momentum generation by a combined neoclassical and turbulence mechanism in diverted DIII-D plasma edge

    SciTech Connect (OSTI)

    Seo, Janghoon; Choe, W.; Chang, C. S.; Ku, S.; Kwon, J. M.; Mller, 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 Mller 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, Mller 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.

  13. PISCES Program: Plasma-materials interactions and edge-plasma physics research. Progress report, 1991--1992

    SciTech Connect (OSTI)

    Conn, R.W.; Hirooka, Y.

    1992-07-01

    This program investigates and characterizes the behavior of materials under plasma bombordment, in divertor regions. The PISCES facility is used to study divertor and plasma edge management concepts (in particular gas target divertors), as well as edge plasma turbulence and transport. The plasma source consists of a hot LaB{sub 6} cathode with an annular, water-cooled anode and attached drift tube. This cross sectional area of the plasma can be adjusted between 3 and 10 cm. A fast scanning diagnostic probe system was used for mapping plasma density profiles during biased limiter and divertor simulation experiments. Some experimental data are given on: (1) materials and surface physics, (2) edge plasma physics, and (3) a theoretical analysis of edge plasma modelling.

  14. UCLA program in theory and modeling of edge physics and plasma material interaction. Progress report, June 1991--June 1992

    SciTech Connect (OSTI)

    Conn, R.W.; Najmabadi, F.; Grossman, A.; Merriman, B.; Day, M.

    1992-12-31

    Our research activity in edge plasma modeling is directed towards understanding edge plasma behavior and towards innovative solutions for controlling the edge plasma as well as the design and operation of impurity control, particle exhaust. and plasma facing components. During the last nine months, substantial progress was made in many areas. The highlights are: (A) Development of a second-generation edge-plasma simulation code (Section II); (B) Development of models for gas-target divertors, including a 1{1/2}-D fluid model for plasma and Monte Carlo neutral-transport simulations (Section III); and (C) Utilization of the RF ponderomotive force and electrostatic biasing to distribute the heat load on a larger area of the divertor plate, and the development of analytical and numerical transport models that include both ponderomotive and electrostatic potentials.

  15. Probing single magnon excitations in Sr₂IrO₄ using O K-edge resonant inelastic x-ray scattering

    SciTech Connect (OSTI)

    Liu, X.; Dean, M. P. M.; Liu, J.; Chiuzbaian, S. G.; Jaouen, N.; Nicolaou, A.; Yin, W. G.; Rayan Serrao, C.; Ramesh, R.; Ding, H.; Hill, J. P.

    2015-04-28

    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 Sr₂IrO₄, 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.

  16. Band-gap and band-edge engineering of multicomponent garnet scintillators from first principles

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yadav, Satyesh K.; Uberuaga, Blas P.; Nikl, Martin; Jiang, Chao; Stanek, Christopher R.

    2015-11-24

    Complex doping schemes in R3Al5O12 (where R is the rare-earth element) garnet compounds have recently led to pronounced improvements in scintillator performance. Specifically, by admixing lutetium and yttrium aluminate garnets with gallium and gadolinium, the band gap is altered in a manner that facilitates the removal of deleterious electron trapping associated with cation antisite defects. Here, we expand upon this initial work to systematically investigate the effect of substitutional admixing on the energy levels of band edges. Density-functional theory and hybrid density-functional theory (HDFT) are used to survey potential admixing candidates that modify either the conduction-band minimum (CBM) or valence-bandmore » maximum (VBM). We consider two sets of compositions based on Lu3B5O12 where B is Al, Ga, In, As, and Sb, and R3Al5O12, where R is Lu, Gd, Dy, and Er. We find that admixing with various R cations does not appreciably affect the band gap or band edges. In contrast, substituting Al with cations of dissimilar ionic radii has a profound impact on the band structure. We further show that certain dopants can be used to selectively modify only the CBM or the VBM. Specifically, Ga and In decrease the band gap by lowering the CBM, while As and Sb decrease the band gap by raising the VBM, the relative change in band gap is quantitatively validated by HDFT. These results demonstrate a powerful approach to quickly screen the impact of dopants on the electronic structure of scintillator compounds, identifying those dopants which alter the band edges in very specific ways to eliminate both electron and hole traps responsible for performance limitations. Furthermore, this approach should be broadly applicable for the optimization of electronic and optical performance for a wide range of compounds by tuning the VBM and CBM.« less

  17. The Network Completion Problem: Inferring Missing Nodes and Edges in Networks

    SciTech Connect (OSTI)

    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.

  18. Salient issues of edge physics pertaining to loss of confinement: A resistive MHD analysis. Technical progress report, FY91

    SciTech Connect (OSTI)

    Thayer, D.R.

    1991-12-31

    The progress that has been made during this fiscal year is significant in the area of tokamak edge plasma transport. Important contributions on the extension of the drift-rippling mode model ({approximately} {tau}, {approximately}n, {approximately}T, {approximately}{nu}{sub {parallel}}) of edge turbulent transport. In particular, the research areas on which we have concentrated include the following topics: (1) The theoretical investigation of the radiatively enhanced transport due to the effects of impurity driven radiation instabilities has been expanded to include a situation with multiple impurities (such as carbon, C{sup 4+}, and oxygen, O{sup 6+}); (2) In order to validate the use of the impurity radiation input from the tokamak bolometer experiments in our theoretical edge turbulent transport calculations, the analysis that is utilized to transform impurity brightness data to radiated power profiles has been checked for state population and Abel inversion correctness; (3) The drift-rippling model of edge turbulent transport has been extended to include ionization particle sources in addition to the impurity driven thermal instability drive; and (4) The detailed limiter and realistic edge geometric effects on the edge turbulent transport has been included in the drift-rippling model.

  19. Salient issues of edge physics pertaining to loss of confinement: A resistive MHD analysis. FY91 technical progress report

    SciTech Connect (OSTI)

    Thayer, D.R.

    1991-12-31

    The progress that has been made during this fiscal year is significant in the area of tokamak edge plasma transport. The drift-rippling mode model of edge turbulent transport was extended. In particular, the research areas on which were concentrated include the following topics: (1) The theoretical investigation of the radiatively enhanced transport due to the effects of impurity driven radiation instabilities has been expanded to include a situation with multiple impurities (such as carbon, C{sup 4+}, and oxygen, O{sup 6+}); (2) In order to validate the use of the impurity radiation input from the tokamak bolometer experiments in the theoretical edge turbulent transport calculations, the analysis that is utilized to transform impurity brightness data to radiated power profiles has been checked for state population and Abel inversion correctness; (3) The drift-rippling model of edge turbulent transport has been extended to include ionization particle sources in addition to the impurity driven thermal instability drive; and (4) The detailed limiter and realistic edge geometric effects on the edge turbulent transport has been included in the drift-rippling model.

  20. Measurement of quasiparticle transport in aluminum films using tungsten transition-edge sensors

    SciTech Connect (OSTI)

    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.

  1. High confinement mode and edge localized mode characteristics in a near-unity aspect ratio tokamak

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Thome, Kathreen E.; Bongard, Michael W.; Barr, Jayson L.; Bodner, Grant M.; Burke, Marcus G.; Fonck, Raymond J.; Kriete, David M.; Perry, Justin M.; Schlossberg, David J.

    2016-04-27

    Tokamak experiments at near-unity aspect ratio A ≲ 1.2 offer new insights into the self-organized H-mode plasma confinement regime. In contrast to conventional A ~ 3 plasmas, the L–H power threshold PLH is ~15× higher than scaling predictions, and it is insensitive to magnetic topology, consistent with modeling. Edge localized mode (ELM) instabilities shift to lower toroidal mode numbers as A decreases. Furthermore, these ultralow-A operations enable heretofore inaccessible Jedge(R,t) measurements through an ELM that show a complex multimodal collapse and the ejection of a current-carrying filament.

  2. Reduced-magnetohydrodynamic simulations of toroidally and poloidally localized edge localized modes

    SciTech Connect (OSTI)

    Hoelzl, M.; Guenter, S.; Mueller, W.-C.; Lackner, K.; Krebs, I.; Wenninger, R. P.; Huysmans, G. T. A.; Collaboration: ASDEX Upgrade Team

    2012-08-15

    We use the non-linear reduced-magnetohydrodynamic code JOREK to study edge localized modes (ELMs) in the geometry of the ASDEX Upgrade tokamak. Toroidal mode numbers, poloidal filament sizes, and radial propagation speeds of filaments into the scrape-off layer are in good agreement with observations for type-I ELMs in ASDEX Upgrade. The observed instabilities exhibit a toroidal and poloidal localization of perturbations which is compatible with the 'solitary magnetic perturbations' recently discovered in ASDEX Upgrade [R. Wenninger et al., 'Solitary magnetic perturbations at the ELM onset,' Nucl. Fusion (accepted)]. This localization can only be described in numerical simulations with high toroidal resolution.

  3. Turbulent electron transport in edge pedestal by electron temperature gradient turbulence

    SciTech Connect (OSTI)

    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.

  4. The use of bulk states to accelerate the band edge statecalculation of a semiconductor quantum dot

    SciTech Connect (OSTI)

    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.

  5. Final Report for the "Fusion Application for Core-Edge Transport Simulations (FACETS)"

    SciTech Connect (OSTI)

    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 team’s 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.

  6. Development of a Leave-in-Place Slab Edge Insulating Form System

    SciTech Connect (OSTI)

    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

  7. From UNIVACs to ESnet, John Christman's Retiring from the Leading Edge of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Technology From UNIVACs to ESnet, John Christman's Retiring from the Leading Edge of Technology News & Publications ESnet News Media & Press Publications and Presentations Galleries ESnet Awards and Honors Contact Us Media Jon Bashor, jbashor@lbl.gov, +1 510 486 5849 or Media@es.net Technical Assistance: 1 800-33-ESnet (Inside the US) 1 800-333-7638 (Inside the US) 1 510-486-7600 (Globally) 1 510-486-7607 (Globally) Report Network Problems: trouble@es.net Provide Web Site Feedback:

  8. Blob structure and motion in the edge and SOL of NSTX

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zweben, S. J.; Myra, J. R.; Davis, W. M.; D’Ippolito, D. A.; Gray, T. K.; Kaye, S. M.; LeBlanc, B. P.; Maqueda, R. J.; Russell, D. A.; Stotler, D. P.

    2016-01-28

    Here, the structure and motion of discrete plasma blobs (a.k.a. filaments) in the edge and scrape-off layer of NSTX is studied for representative Ohmic and H-mode discharges. Individual blobs were tracked in the 2D radial versus poloidal plane using data from the gas puff imaging diagnostic taken at 400 000 frames s-1. A database of blob amplitude, size, ellipticity, tilt, and velocity was obtained for ~45 000 individual blobs. Empirical relationships between various properties are described, e.g. blob speed versus amplitude and blob tilt versus ellipticity. The blob velocities are also compared with analytic models.

  9. Beyond Pluto: The Search for the Edge of the Solar System

    SciTech Connect (OSTI)

    Funsten, Herb

    2015-08-12

    In July, we finally visited the last major body of our solar system, Pluto. But what lies beyond? The stellar wind from our Sun forms an enormous bubble in interstellar space. This “sphere of our Sun,” or heliosphere, extends far beyond Pluto and forms a protective cocoon that shields us from cosmic radiation. In this talk, we will travel to the edge of the solar system, peer into the structure and dynamics of the outer heliosphere as it interacts with the interstellar medium and anticipate the future of the solar system as it moves through our galactic neighborhood.

  10. Excitonic effects of E11, E22, and E33 in armchair-edged graphene nanoribbons

    SciTech Connect (OSTI)

    Lu, Yan; Zhao, Shangqian; Lu, Wengang Liang, Wenjie; Liu, Hong

    2014-03-14

    We explore excitonic effects of E11, E22, and E33, which are excitons formed between the three highest valence subbands and the three lowest conduction ones, in armchair-edged graphene nanoribbons by applying the extended tight-binding model including electron-electron interactions. Our results show that the excitation energies and the binding energies decrease inversely with the ribbon widths and can be classified into three categories based on their width indices. We found the relation between the band structures and the binding energies and explained some recent observations of strong excitonic effects in graphene.

  11. Physicist John Schmidt, designer of cutting-edge fusion facilities, dies at

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    72 | Princeton Plasma Physics Lab Physicist John Schmidt, designer of cutting-edge fusion facilities, dies at 72 By John Greenwald February 15, 2013 Tweet Widget Google Plus One Share on Facebook John Schmidt, 1940-2013 (Photo by Elle Starkman) John Schmidt, 1940-2013 Physicist John Schmidt, whose profound and wide-ranging contributions to the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) made him a highly respected leader in the worldwide quest for fusion energy,

  12. Autoignited laminar lifted flames of propane in coflow jets with tribrachial edge and mild combustion

    SciTech Connect (OSTI)

    Choi, B.C.; Kim, K.N.; Chung, S.H.

    2009-02-15

    Characteristics of laminar lifted flames have been investigated experimentally by varying the initial temperature of coflow air over 800 K in the non-premixed jets of propane diluted with nitrogen. The result showed that the lifted flame with the initial temperature below 860 K maintained the typical tribrachial structure at the leading edge, which was stabilized by the balance mechanism between the propagation speed of tribrachial flame and the local flow velocity. For the temperature above 860 K, the flame was autoignited without having any external ignition source. The autoignited lifted flames were categorized in two regimes. In the case with tribrachial edge structure, the liftoff height increased nonlinearly with jet velocity. Especially, for the critical condition near blowout, the lifted flame showed a repetitive behavior of extinction and reignition. In such a case, the autoignition was controlled by the non-adiabatic ignition delay time considering heat loss such that the autoignition height was correlated with the square of the adiabatic ignition delay time. In the case with mild combustion regime at excessively diluted conditions, the liftoff height increased linearly with jet velocity and was correlated well with the square of the adiabatic ignition delay time. (author)

  13. Edge effects in propagation of terahertz radiation in subwavelength periodic structures

    SciTech Connect (OSTI)

    Gelmont, B. Parthasarathy, R.; Globus, T.

    2008-08-15

    Improving detection sensitivity of biological molecules with low absorption characteristics in the terahertz gap still remains an important issue in terahertz vibrational resonance spectroscopy. One possible way to increase coupling of incident terahertz radiation to molecules is to exploit local enhancement of electromagnetic field in periodic slot arrays. In this work, we show that periodic arrays of rectangular slots with subwavelength widths provide for local electromagnetic field enhancements due to edge effects in our low frequency range of interest, 10-25 cm{sup -1}. Periodic structures of Au doped Si and InSb were studied. The half power enhancement width is {approx}500 nm or less around the slot, edges in all cases, thereby possibly bringing terahertz sensing to the nanoscale. InSb is confirmed to offer the highest results with local power enhancements on the order of 1100 at frequency 14 cm{sup -1}. InSb and Si have large skin depths in our frequency range of interest and so the analysis of their structures was done through the Fourier expansion method of field diffracted from gratings. Surface impedance boundary conditions were employed to model the Au structure. The applications possibly include development of novel biosensors, and monitoring biophysical processes such as DNA denaturation.

  14. Constructing compact and effective graphs for recommender systems via node and edge aggregations

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lee, Sangkeun; Kahng, Minsuk; Lee, Sang-goo

    2014-12-10

    Exploiting graphs for recommender systems has great potential to flexibly incorporate heterogeneous information for producing better recommendation results. As our baseline approach, we first introduce a naive graph-based recommendation method, which operates with a heterogeneous log-metadata graph constructed from user log and content metadata databases. Although the na ve graph-based recommendation method is simple, it allows us to take advantages of heterogeneous information and shows promising flexibility and recommendation accuracy. However, it often leads to extensive processing time due to the sheer size of the graphs constructed from entire user log and content metadata databases. In this paper, we proposemore » node and edge aggregation approaches to constructing compact and e ective graphs called Factor-Item bipartite graphs by aggregating nodes and edges of a log-metadata graph. Furthermore, experimental results using real world datasets indicate that our approach can significantly reduce the size of graphs exploited for recommender systems without sacrificing the recommendation quality.« less

  15. Computer modeling of electromagnetic edge containment in twin-roll casting

    SciTech Connect (OSTI)

    Chang, F.C.; Turner, L.R.; Hull, J.R.; Wang, Y.H.; Blazek, K.E.

    1998-07-01

    This paper presents modeling studies of magnetohydrodynamics (MHD) analysis in twin-roll casting. Argonne National Laboratory (ANL) and Inland Steel Company have worked together to develop a 3-D computer model that can predict eddy currents, fluid flows, and liquid metal containment for an electromagnetic (EM) edge containment device. This mathematical model can greatly shorten casting research on the use of EM fields for liquid metal containment and control. It can also optimize the existing casting processes and minimize expensive, time-consuming full-scale testing. The model was verified by comparing predictions with experimental results of liquid-metal containment and fluid flow in EM edge dams designed at Inland Steel for twin-roll casting. Numerical simulation was performed by coupling a three-dimensional (3-D) finite-element EM code (ELEKTRA) and a 3-D finite-difference fluids code (CaPS-EM) to solve Maxwell`s equations, Ohm`s law, Navier-Stokes equations, and transport equations of turbulence flow in a casting process that uses EM fields. ELEKTRA is able to predict the eddy-current distribution and electromagnetic forces in complex geometry. CaPS-EM is capable of modeling fluid flows with free-surfaces and dynamic rollers. The computed 3-D magnetic fields and induced eddy currents in ELEKTRA are used as input to flow-field computations in CaPS-EM. Results of the numerical simulation compared well with measurements obtained from both static and dynamic tests.

  16. Edge gradient and safety factor effects on electrostatic turbulent transport in tokamaks

    SciTech Connect (OSTI)

    Tan, Ing Hwie

    1992-05-01

    Electrostatic turbulence and transport measurements are performed on the Tokapole-II tokamak at the University of Wisconsin-Madison, as the safety-factor and the edge equilibrium gradients and varied substantially. Tokapole-II is a poloidal divertor tokamak capable of operating at a wide range of safety factors due to its unique magnetic limiter configuration. It also has retractable material limiters in a large scrape-off region, which permits the study of edge boundary conditions like density and temperature gradients. The turbulence is independent of safety factor, but strongly sensitive to the local density gradient, which itself depends upon the limiter configuration. When a material limiter is inserted in a high discharge, the density gradient is increased locally together with a local increase of the turbulence. On the other hand, limiter insertion in low discharges did not increase the density gradient as much and the turbulence properties are unchanged with respect to the magnetic limiter case. It is conducted then, that electrostatic turbulence is caused by the density gradient. Although the electrostatic fluctuation driven transport is enhanced in the large density gradient case, it is in all cases to small to explain the observed energy confinement times. To explore instabilities with small wavelengths, a 0.5 mm diameter shperical Langmuir probe was constructed, and its power compared with the power measured by larger cylindrical probes.

  17. Li K-Edge XANES Spectra of Lithium Niobate and Lithium Tantalite

    SciTech Connect (OSTI)

    Mizota, H.; Ito, Y.; Tochio, T.; Handa, K.; Takekawa, S.; Kitamura, K.

    2007-02-02

    The x-ray emission with the single crystal of lithium niobate (LiNbO3) or lithium tantalite (LiTaO3) by thermal changes in a vacuum system is closely concerned with the electronic state of each crystal. Therefore, lithium K-edge x-ray absorption near edge structures (XANES) spectra of these materials were measured in the region from 50 eV to 90 eV by means of total electron yield method (T.E.Y.), using the extremely soft x-ray. Samples were powder of lithium carbonate (Li2CO3) and single crystal of lithium fluoride (LiF), LiNbO3 and LiTaO3 in order to compare the shapes of these XANES spectra. Various peak structures appear in these spectra in the range from 55 eV to 80 eV and each spectrum has different shapes as a result of the difference of bond length and bond angles for the atoms which are in less than 60 nm from the absorbing atom. The relationship between these spectra and the electronic states was discussed by FEFF 8.

  18. Development of lithium beam emission spectroscopy as an edge fluctuation diagnostic for DIII-D

    SciTech Connect (OSTI)

    Thomas, D.M.

    1994-05-01

    As part of the DIII-D diagnostic complement designed to address L-H transition physics issues, we have developed and commissioned a diagnostic neutral lithium beam and multichannel fluorescence detection system to investigate the edge plasma density and its associated fluctuations. The use of lithium offers several advantages for tokamak edge beam emission spectroscopy (BES) studies, including large excitation cross sections which are relatively insensitive to temperature variation, the availability of the 670.8 nm resonance line well separated from most plasma line emission, and the suitability of modest beam energies and currents to probe even dense H-mode plasmas. These features permit measurements of collisionally induced fluctuations to be obtained with good spatial (<1 cm) and temporal (<10 {mu}s) resolution. The improvements over previous lithium beam diagnostics which were required to successfully make these measurements in a large, remotely controlled machine environment will be discussed, a long with the present state of the diagnostic system and our plans for future improvements of this technique.

  19. MICROWAVE OBSERVATIONS OF EDGE-ON PROTOPLANETARY DISKS: PROGRAM OVERVIEW AND FIRST RESULTS

    SciTech Connect (OSTI)

    Melis, Carl; Duchene, G.; Chomiuk, Laura; Palmer, Patrick; Perrin, M. D.; Maddison, S. T.; Menard, F.; Pinte, C.; Duvert, G.

    2011-09-20

    We are undertaking a multi-frequency Expanded Very Large Array (EVLA) survey of edge-on protoplanetary disks to probe the growth of solids in each disk, sedimentation of such material into the disk midplane, and the connection of these phenomena to the planet formation process. The projection of edge-on disk systems along our line of sight enables a study of the vertical stratification of large grains with fewer model dependencies than would be required for disks that are more face-on. Robust studies of the spatial distribution of grains up to {approx}1 cm in size are possible with the wavelength range and sensitivity of the EVLA. In this contribution, we describe target selection and observational strategies. First results concerning the Class 0 source IRAS 04368+2557 (L1527 IRS) are presented, including a study of this source's 8.46 GHz continuum variability over short and long time baselines and an indication that its protoplanetary disk may have a dearth of pebble-sized grains.

  20. Computer simulation of the L/sub III/-edge densitometer

    SciTech Connect (OSTI)

    Langner, D.

    1987-11-01

    Since the L/sub III/-edge densitometer was first fielded in 1977, it has displayed a 1 to 1.5% nonlinear deviation from its theoretical linear calibration response. In an effort to explain this nonlinear deviation, this study used a simple, closed-form computer simulation to examine the effects of several variables on the densitometer's measurement of uranium and plutonium in solution. The results of this simulation suggest that the variables that contribute to this nonlinearity include the effects of small-angle scattering and the detection system resolution function. The simulation also examined the effects of matrix contaminants, the shape of the incoming beam, the uranium-to-plutonium ratio for mixed solutions, and the data-reduction technique. All of these variables were found to have some effect on the assay results, although these were generally small. The calculations demonstrate that using a new edge-extrapolation data-reduction technique reduces the instrument's sensitivity to many of these variables.

  1. Measurement of LHCD edge power deposition through modulation techniques on Alcator C-Mod

    SciTech Connect (OSTI)

    Faust, I. C.; Brunner, D.; LaBombard, B.; Parker, R. R.; Baek, S. G.; Chilenksi, M. A.; Hubbard, A.; Hughes, J. W.; Terry, J. L.; Shiraiwa, S.; Walk, J. R.; Wallace, G. M.; Whyte, D. G.; Edlund, E.

    2015-12-10

    The efficiency of LHCD on Alcator C-Mod drops exponentially with line average density. At reactor relevant densities (> 1 · 1020 [m{sup −3}]) no measurable current is driven. While a number of causes have been suggested, no specific mechanism has been shown to be responsible for the loss of current drive at high density. Fast modulation of the LH power was used to isolate and quantify the LHCD deposition within the plasma. Measurements from these plasmas provide unique evidence for determining a root cause. Modulation of LH power in steady plasmas exhibited no correlated change in the core temperature. A correlated, prompt response in the edge suggests that the loss in efficiency is related to a edge absorption mechanism. This follows previous results which found the generation of n{sub ||}-independent SOL currents. Multiple Langmuir probe array measurements of the conducted heat conclude that the lost power is deposited near the last closed flux surface. The heat flux induced by LH waves onto the outer divertor is calculated. Changes in the neutral pressure, ionization and hard X-ray emission at high density highlight the importance of the active divertor in the loss of efficiency. Results of this study implicate a mechanism which may occur over multiple passes, leading to power absorption near the LCFS.

  2. Tool holder for preparation and inspection of a radiused edge cutting tool

    DOE Patents [OSTI]

    Asmanes, Charles

    1979-01-01

    A tool holding fixture is provided for removably holding a radiused edge cutting tool in a tool edge lapping apparatus. The fixture allows the operator to preset the lapping radius and angle before the tool holder is placed in the fixture and the holder may be removed from the lapping apparatus to inspect the tool and simply replaced in the fixture to continue lapping in accordance with a precise alignment without realignment of the tool relative to the lap. The tool holder includes a pair of self aligning bearings in the form of precision formed steel balls connected together by a rigid shaft. The tool is held by an arm extending from the shaft and the balls set in fixed position bearing cups and the holder is oscillated back and forth about a fixed axis of rotation to lap the tool radius by means of a reversibly driven belt-pulley arrangement coupled to the shaft between the bearings. To temporarily remove the holder, the drive belt is slipped over the rearward end of the holder and the holder is lifted out of the bearing cups.

  3. Tailoring of absorption edge by thermal annealing in tin oxide thin films

    SciTech Connect (OSTI)

    Thakur, Anup; Gautam, Sanjeev; Kumar, Virender; Chae, K. H.; Lee, Ik-Jae; Shin, Hyun Joon

    2015-05-15

    Tin oxide (SnO{sub 2}) thin films were deposited by radio-frequency (RF) magnetron sputtering on silicon and glass substrates in different oxygen-to-argon gas-flow ratio (O{sub 2}-to-Ar = 0%, 10%, 50%). All films were deposited at room temperature and fixed working pressures, 10 mTorr. The X-ray diffraction (XRD) measurement suggests that all films were crystalline in nature except film deposited in argon environment. Thin films were annealed in air at 200 C, 400 C and 600 C for two hours. All films were highly transparent except the film deposited only in the argon environment. It was also observed that transparency was improved with annealing due to decrease in oxygen vacancies. Atomic force microscopy (AFM), results showed that the surface of all the films were highly flat and smooth. Blue shift was observed in the absorption edge with annealing temperature. It was also observed that there was not big change in the absorption edge with annealing for films deposited in 10% and 50% oxygen-to-argon gas-flow ratio.

  4. Analytical and numerical study of the transverse Kelvin-Helmholtz instability in tokamak edge plasmas

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Myra, James R.; D'Ippolito, Daniel A.; Russell, David A.; Umansky, Maxim V.; Baver, Derek A.

    2016-04-11

    Sheared flows perpendicular to the magnetic field can be driven by the Reynolds stress or ion pressure gradient effects and can potentially influence the stability and turbulent saturation level of edge plasma modes. On the other hand, such flows are subject to the transverse Kelvin- Helmholtz (KH) instability. Here, the linear theory of KH instabilities is first addressed with an analytic model in the asymptotic limit of long wavelengths compared with the flow scale length. The analytic model treats sheared ExB flows, ion diamagnetism (including gyro-viscous terms), density gradients and parallel currents in a slab geometry, enabling a unified summarymore » that encompasses and extends previous results. In particular, while ion diamagnetism, density gradients and parallel currents each individually reduce KH growth rates, the combined effect of density and ion pressure gradients is more complicated and partially counteracting. Secondly, the important role of realistic toroidal geometry is explored numerically using an invariant scaling analysis together with the 2DX eigenvalue code to examine KH modes in both closed and open field line regions. For a typical spherical torus magnetic geometry, it is found that KH modes are more unstable at and just outside the separatrix as a result of the distribution of magnetic shear. Lastly implications for reduced edge turbulence modeling codes are discussed.« less

  5. Fabrication of gas impervious edge seal for a bipolar gas distribution assembly for use in a fuel cell

    DOE Patents [OSTI]

    Kaufman, Arthur; Werth, John

    1986-01-01

    A bipolar gas reactant distribution assembly for use in a fuel cell is disclosed, the assembly having a solid edge seal to prevent leakage of gaseous reactants wherein a pair of porous plates are provided with peripheral slits generally parallel to, and spaced apart from two edges of the plate, the slit being filled with a solid, fusible, gas impervious edge sealing compound. The plates are assembled with opposite faces adjacent one another with a layer of a fusible sealant material therebetween the slits in the individual plates being approximately perpendicular to one another. The plates are bonded to each other by the simultaneous application of heat and pressure to cause a redistribution of the sealant into the pores of the adjacent plate surfaces and to cause the edge sealing compound to flow and impregnate the region of the plates adjacent the slits and comingle with the sealant layer material to form a continuous layer of sealant along the edges of the assembled plates.

  6. Processes and properties of edge-localised instabilities in 2T 2MA plasmas in the Joint European Torus

    SciTech Connect (OSTI)

    Webster, A. J. Webster, S. J.

    2014-11-15

    During July 2012, 150 almost identical H-mode plasmas were consecutively created in the Joint European Torus, providing a combined total of approximately 8 minutes of steady-state plasma with 15?000 Edge Localised Modes (ELMs). In principle, each of those 15?000 ELMs are statistically equivalent. Here, the changes in edge density and plasma energy associated with those ELMs are explored, using the spikes in Beryllium II (527?nm) radiation as an indicator for the onset of an ELM. Clearly different timescales are observed during the ELM process. Edge temperature falls over a 2?ms timescale, edge density and pressure fall over a 5?ms timescale, and there is an additional 10?ms timescale that is consistent with a resistive relaxation of the plasma's edge. The statistical properties of the energy and density losses due to the ELMs are explored. For these plasmas the ELM energy (?E) is found to be approximately independent of the time between ELMs, despite the average ELM energy (??E?) and average ELM frequency (f) being consistent with the scaling of ??E??1/f. Instead, beyond the first 0.02 s of waiting time between ELMs, the energy losses due to individual ELMs are found to be statistically the same. Surprisingly no correlation is found between the energies of consecutive ELMs either. A weak link is found between the density drop and the ELM waiting time. Consequences of these results for ELM control and modelling are discussed.

  7. Hydrogenation-induced edge magnetization in armchair MoS{sub 2} nanoribbon and electric field effects

    SciTech Connect (OSTI)

    Ouyang, Fangping; Yang, Zhixiong; Wu, Nannan; Chen, Yu; Ni, Xiang; Xiong, Xiang

    2014-02-17

    We performed density functional theory study on the electronic and magnetic properties of armchair MoS{sub 2} nanoribbons (AMoS{sub 2}NR) with different edge hydrogenation. Although bare and fully passivated AMoS{sub 2}NRs are nonmagnetic semiconductors, it was found that hydrogenation in certain patterns can induce localized ferromagnetic edge state in AMoS{sub 2}NRs and make AMoS{sub 2}NRs become antiferromagnetic semiconductors or ferromagnetic semiconductors. Electric field effects on the bandgap and magnetic moment of AMoS{sub 2}NRs were investigated. Partial edge hydrogenation can change a small-sized AMoS{sub 2}NR from semiconductor to metal or semimetal under a moderate transverse electric field. Since the rate of edge hydrogenation can be controlled experimentally via the temperature, pressure and concentration of H{sub 2}, our results suggest edge hydrogenation is a useful method to engineer the band structure of AMoS{sub 2}NRs.

  8. The impact of pedestal turbulence and electron inertia on edge-localized-mode crashes

    SciTech Connect (OSTI)

    Xi, P. W.; Lawrence Livermore National Laboratory, Livermore, California 94550 ; Xu, X. Q.; Diamond, P. H.; Center for Astrophysics and Space Sciences and Department of Physics, University of California San Diego, La Jolla, California 92093-0429

    2014-05-15

    We demonstrate that the occurrence of Edge-Localized-Modes (ELM) crashes does not depend only on the linear peeling-ballooning threshold, but also relies on nonlinear processes. Wave-wave interaction constrains the growth time of a mode, thus inducing a shift in the criterion for triggering an ELM crash. An ELM crash requires the P-B growth rate to exceed a critical value ?>?{sub c}, where ?{sub c} is set by 1/?{sup }{sub c}, and ?{sup }{sub c} is the averaged mode phase coherence time. For 0

  9. Computer modeling of electromagnetic fields and fluid flows for edge containment in continuous casting

    SciTech Connect (OSTI)

    Chang, F.C.; Hull, J.R.; Wang, Y.H.; Blazek, K.E.

    1996-02-01

    A computer model was developed to predict eddy currents and fluid flows in molten steel. The model was verified by comparing predictions with experimental results of liquid-metal containment and fluid flow in electromagnetic (EM) edge dams (EMDs) designed at Inland Steel for twin-roll casting. The model can optimize the EMD design so it is suitable for application, and minimize expensive, time-consuming full-scale testing. Numerical simulation was performed by coupling a three-dimensional (3-D) finite-element EM code (ELEKTRA) and a 3-D finite-difference fluids code (CaPS-EM) to solve heat transfer, fluid flow, and turbulence transport in a casting process that involves EM fields. ELEKTRA is able to predict the eddy- current distribution and the electromagnetic forces in complex geometries. CaPS-EM is capable of modeling fluid flows with free surfaces. Results of the numerical simulation compared well with measurements obtained from a static test.

  10. Constraints on the inner edge of neutron star crusts from relativistic nuclear energy density functionals

    SciTech Connect (OSTI)

    Moustakidis, Ch. C.; Lalazissis, G. A.; Niksic, T.; Vretenar, D.; Ring, P.

    2010-06-15

    The transition density n{sub t} and pressure P{sub t} at the inner edge between the liquid core and the solid crust of a neutron star are analyzed using the thermodynamical method and the framework of relativistic nuclear energy density functionals. Starting from a functional that has been carefully adjusted to experimental binding energies of finite nuclei, and varying the density dependence of the corresponding symmetry energy within the limits determined by isovector properties of finite nuclei, we estimate the constraints on the core-crust transition density and pressure of neutron stars: 0.086 fm{sup -3}<=n{sub t}<0.090 fm{sup -3} and 0.3 MeV fm{sup -3}

  11. High-efficiency graphene nanomesh magnets realized by controlling mono-hydrogenation of pore edges

    SciTech Connect (OSTI)

    Kato, T.; Kamijyo, J.; Kobayashi, T.; Yagi, Y.; Haruyama, J.; Nakamura, T.

    2014-06-23

    We demonstrate a drastic improvement in the efficiency of rare-element-free graphene nanomesh (GNM) magnets with saturation magnetization values as large as ∼10{sup −4 }emu/mm{sup 2}, which are 10–100 times greater than those in previous GNM magnets hydrogenated by only annealing under a hydrogen molecule (H{sub 2}) atmosphere, even at room temperature. This improvement is realized by a significant increase in the area of the mono-H-terminated pore edges by using hydrogen silsesquioxane resist treatment with electron beam irradiation, which can produce mono-H by detaching H-silicon (Si) bonds. This result must open the door for industrial applications of graphene magnets to rare-element-free magnetic and spintronic systems.

  12. Disorder-free localization around the conduction band edge of crossing and kinked silicon nanowires

    SciTech Connect (OSTI)

    Kele?, mit; akan, Asl?; Bulutay, Ceyhun

    2015-02-14

    We explore ballistic regime quantum transport characteristics of oxide-embedded crossing and kinked silicon nanowires (NWs) within a large-scale empirical pseudopotential electronic structure framework, coupled to the Kubo-Greenwood transport analysis. A real-space wave function study is undertaken and the outcomes are interpreted together with the findings of ballistic transport calculations. This reveals that ballistic transport edge lies tens to hundreds of millielectron volts above the lowest unoccupied molecular orbital, with a substantial number of localized states appearing in between, as well as above the former. We show that these localized states are not due to the oxide interface, but rather core silicon-derived. They manifest the wave nature of electrons brought to foreground by the reflections originating from NW junctions and bends. Hence, we show that the crossings and kinks of even ultraclean Si NWs possess a conduction band tail without a recourse to atomistic disorder.

  13. Ventilation efficiencies of a desk-edge-mounted task ventilation system

    SciTech Connect (OSTI)

    Faulkner, David; Fisk, William J.; Sullivan, Douglas P.; Lee, Seung Min

    2002-03-01

    In chamber experiments, we investigated the effectiveness of a task ventilation system with an air supply nozzle located underneath the front edge of a desk and directing air toward a heated mannequin seated at the desk. The task ventilation system provided outside air, while another ventilation system provided additional space cooling but no outside air. Test variables included the vertical angle of air supply (-15{sup o} to 45{sup o} from horizontal), and the supply flow rate of (3.5 to 6.5 L s{sup -1}). Using the tracer gas step-up and step-down procedures, the measured air change effectiveness (i.e., exhaust air age divided by age of air at the mannequin's face) ranged from 1.4 to 2.7, which is higher than typically reported for commercially available task ventilation or displacement ventilation systems.

  14. Measurement of an inverse Compton scattering source local spectrum using k-edge filters

    SciTech Connect (OSTI)

    Golosio, Bruno; Oliva, Piernicola; Carpinelli, Massimo; Endrizzi, Marco; Delogu, Pasquale; Pogorelsky, Igor; Yakimenko, Vitaly

    2012-04-16

    X-ray sources based on the inverse Compton scattering process are attracting a growing interest among scientists, due to their extremely fast pulse, quasi-monochromatic spectrum, and relatively high intensity. The energy spectrum of the x-ray beam produced by inverse Compton scattering sources in a fixed observation direction is a quasi-monochromatic approximately Gaussian distribution. The mean value of this distribution varies with the scattering polar angle between the electron beam direction and the x-ray beam observation direction. Previous works reported experimental measurements of the mean energy as a function of the polar angle. This work introduces a method for the measurement of the whole local energy spectrum (i.e., the spectrum in a fixed observation direction) of the x-ray beam yielded by inverse Compton scattering sources, based on a k-edge filtering technique.

  15. Impact of inward turbulence spreading on energy loss of edge-localized modes

    SciTech Connect (OSTI)

    Ma, C. H.; Xi, P. W.; Xu, X. Q.; Xia, T. Y.; Snyder, P. B.; Kim, S. S.

    2015-05-15

    Nonlinear two-fluid and gyrofluid simulations show that an edge localized modes (ELM) crash has two phases: fast initial crash of ion temperature perturbation on the Alfvén time scale and slow turbulence spreading. The turbulence transport phase is a slow encroachment of electron temperature perturbation due to the ELM event into pedestal region. Because of the inward turbulence spreading effect, the energy loss of an ELM decreases when density pedestal height increases. The Landau resonance yields the different cross phase-shift of ions and electrons. A 3 + 1 gyro-Landau-fluid model is implemented in BOUT++ framework. The gyrofluid simulations show that the kinetic effects have stabilizing effects on the ideal ballooning mode and the energy loss increases with the pedestal height.

  16. Zonal flow sawteeth and the time period between edge-localized transport bursts in tokamaks

    SciTech Connect (OSTI)

    Kleva, Robert G.; Guzdar, Parvez N.

    2007-01-15

    The time period between particle and energy transport bursts in simulations of tokamak edge turbulence is determined by the magnitude of the diamagnetic drift parameter {alpha}{sub d}{identical_to}{omega}{sub *}/{gamma}{sub 0}, where the diamagnetic drift frequency {omega}{sub *}={rho}{sub s}c{sub s}/L{sub 0}L{sub n} and the characteristic ballooning mode growth rate {gamma}{sub 0}=c{sub s}/(RL{sub n}/2){sup 1/2}. Here, R is the major radius of the torus, L{sub n} is the density gradient scale length, {rho}{sub s} is the ion gyroradius, and c{sub s} is the ion acoustic speed. The scale length L{sub 0} is given by L{sub 0}=2{pi}qR {nu}{sub ei}{rho}{sub s}/2{omega}{sub e}R){sup 1/2}(2R/L{sub n}){sup 1/4}, where q is the safety factor, {nu}{sub ei} is the electron-ion collision frequency, and {omega}{sub e} is the electron cyclotron frequency. When the diamagnetic drift frequency becomes larger than the ballooning mode growth rate ({alpha}{sub d}>1), then the transport in the tokamak edge is characterized by regularly recurring bursts of particles and energy with a single well-defined frequency. As {alpha}{sub d} increases above unity, the time period between the bursts becomes much longer. The temporal dependence of the energy in the zonal flow generated nonlinearly has the appearance of sawteeth.

  17. Demonstration of a high heat removal CVD diamond substrate edge-cooled multichip module

    SciTech Connect (OSTI)

    Peterson, D.W.; Sweet, J.N.; Andaleon, D.D.; Renzi, R.F.; Johnson, D.R.

    1994-05-01

    A single substrate intended for a 3-dimensional (3D) edge-cooled multichip module (MCM) has been built and thermally tested. The substrate, with dimensions 1.9 in. by 2 in., is mounted in a fluid cooled block at one end. To test this cooling architecture and verify the accuracy of thermal models, the authors constructed thermal test modules using alumina (Al{sub 2}O{sub 3}), aluminum nitride (AlN), and CVD diamond substrate materials. Each module was populated with an array of 16 Sandia ATC03 test chips with resistive heaters and temperature sensing diode thermometers. Comparative measurements of the 3 substrates were made in which the top row of 4 die were heated at 5 W each for a total of 20 W. The maximum temperature differences between the heated die and the interface with the cold chuck, {delta}T{sub js}, were 24, 126, and 265{degrees}C for diamond, AIN and alumina, respectively. Measurements on the diamond thermal test module, uniformly heated at a total power of 40 W, gave a measured junction-to-sink temperature of {delta}T{sub js} = 18{degrees}C. This result indicates that the diamond edge-cooled substrate could dissipate a total power {approximately}200 W for a maximum {delta}T{sub js} {approximately}100{degrees}C. If multiple substrates were mounted in the fluid cooled block, spaced 0.075 in. apart, the volumetric power density would be about 880 W/in.

  18. Preliminary study of an angiographic and angio-tomographic technique based on K-edge filters

    SciTech Connect (OSTI)

    Golosio, Bruno; Brunetti, Antonio; Oliva, Piernicola; Carpinelli, Massimo; Luca Masala, Giovanni; Meloni, Francesco; Battista Meloni, Giovanni

    2013-08-14

    Digital Subtraction Angiography is commonly affected by artifacts due to the patient movements during the acquisition of the images without and with the contrast medium. This paper presents a preliminary study on an angiographic and angio-tomographic technique based on the quasi-simultaneous acquisition of two images, obtained using two different filters at the exit of an X-ray tube. One of the two filters (K-edge filter) contains the same chemical element used as a contrast agent (gadolinium in this study). This filter absorbs more radiation with energy just above the so called K-edge energy of gadolinium than the radiation with energy just below it. The other filter (an aluminium filter in this study) is simply used to suppress the low-energy contribution to the spectrum. Using proper calibration curves, the two images are combined to obtain an image of the contrast agent distribution. In the angio-tomographic application of the proposed technique two images, corresponding to the two filter types, are acquired for each viewing angle of the tomographic scan. From the two tomographic reconstructions, it is possible to obtain a three-dimensional map of the contrast agent distribution. The technique was tested on a sample consisting of a rat skull placed inside a container filled with water. Six small cylinders with 4.7 mm internal diameter containing the contrast medium at different concentrations were placed inside the skull. In the plain angiographic application of the technique, five out of six cylinders were visible, with gadolinium concentration down to 0.96%. In the angio-tomographic application, all six cylinders were visible, with gadolinium concentration down to 0.49%. This preliminary study shows that the proposed technique can provide images of the contrast medium at low concentration without most of the artifacts that are present in images produced by conventional techniques. The results encourage further investigation on the feasibility of a clinical

  19. Nonlinear simulations of peeling-ballooning modes with anomalous electron viscosity and their role in edge localized mode crashes

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xu, X. Q.; Dudson, B.; Snyder, P. B.; Umansky, M. V.; Wilson, H.

    2010-10-22

    A minimum set of equations based on the peeling-ballooning (P-B) model with nonideal physics effects (diamagnetic drift, E×B drift, resistivity, and anomalous electron viscosity) is found to simulate pedestal collapse when using the new BOUT++ simulation code, developed in part from the original fluid edge code BOUT. Nonlinear simulations of P-B modes demonstrate that the P-B modes trigger magnetic reconnection, which leads to the pedestal collapse. With the addition of a model of the anomalous electron viscosity under the assumption that the electron viscosity is comparable to the anomalous electron thermal diffusivity, it is found from simulations using a realisticmore » high-Lundquist number that the pedestal collapse is limited to the edge region and the edge localized mode (ELM) size is about 5–10% of the pedestal stored energy. Furthermore, this is consistent with many observations of large ELMs.« less

  20. Probing single magnon excitations in Sr₂IrO₄ using O K-edge resonant inelastic x-ray scattering

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Liu, X.; Dean, M. P. M.; Liu, J.; Chiuzbaian, S. G.; Jaouen, N.; Nicolaou, A.; Yin, W. G.; Rayan Serrao, C.; Ramesh, R.; Ding, H.; et al

    2015-04-28

    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 Sr₂IrO₄, 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-edgemore » RIXS energy resolutions in the hard X-ray region is usually poor.« less

  1. Automated Chemical Analysis of Internally Mixed Aerosol Particles Using X-ray Spectromicroscopy at the Carbon K-Edge

    SciTech Connect (OSTI)

    Moffet, Ryan C.; Henn, Tobias R.; Laskin, Alexander; Gilles, Marry K.

    2010-10-01

    We have developed an automated data analysis method for atmospheric particles using scanning transmission X-ray microscopy coupled with near edge X-ray fine structure spectroscopy (STXM/NEXAFS). This method is applied to complex internally mixed submicron particles containing organic and inorganic material. Several algorithms were developed to exploit NEXAFS spectral features in the energy range from 278-320 eV for quantitative mapping of the spatial distribution of elemental carbon, organic carbon, potassium, and non-carbonaceous elements in particles of mixed composition. This energy range encompasses the carbon K-edge and potassium L2 and L3 edges. STXM/NEXAFS maps of different chemical components were complemented with a subsequent analysis using elemental maps obtained by scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDX). We demonstrate application of the automated mapping algorithms for data analysis and the statistical classification of particles.

  2. Access to edge scenarios for testing a scraper element in early operation phases of Wendelstein 7-X

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Holbe, H.; Pedersen, T. Sunn; Geiger, J.; Bozhenkov, S.; Kornejew, P; Feng, Y.; Lore, Jeremy D.; Lumsdaine, Arnold; Konig, R.

    2016-01-29

    The edge topology of magnetic fusion devices is decisive for the control of the plasma exhaust. In Wendelstein 7-X, the island divertor concept will be used, for which the edge topology can change significantly as the internal currents in a plasma discharge evolve towards steady-state. Consequently, the device has been optimized to minimize such internal currents, in particular the bootstrap current [1]. Nonetheless, there are predicted pulse scenarios where effects of the remaining internal currents could potentially lead to overload of plasma-facing components. These internal currents are predicted to evolve on long time scales (tens of seconds) so their effectsmore » on the edge topology and the divertor heat loads may not be experimentally accessible in the first years of W7-X operation, where only relatively short pulses are possible. However, we show here that for at least one important long-pulse divertor operation issue, relevant physics experiments can be performed already in short-pulse operation, through judicious adjustment of the edge topology by the use of the existing coil sets. The specific issue studied here is a potential overload of the divertor element edges. This overload might be mitigated by the installation of an extra set of plasma-facing components, so-called scraper elements, as suggested in earlier publications. It is shown here that by a targeted control of edge topology, the effectiveness of such scraper elements can be tested already with uncooled test-scraper elements in short-pulse operation. Furthermore, this will allow an early and well-informed decision on whether long-pulse-capable (actively cooled) scraper elements should be built and installed.« less

  3. WARM MOLECULAR HYDROGEN EMISSION IN NORMAL EDGE-ON GALAXIES NGC 4565 AND NGC 5907

    SciTech Connect (OSTI)

    Laine, Seppo; Appleton, Philip N.; Gottesman, Stephen T.; Ashby, Matthew L. N.; Garland, Catherine A. E-mail: apple@ipac.caltech.ed E-mail: mashby@cfa.harvard.ed

    2010-09-15

    We have observed warm molecular hydrogen in two nearby edge-on disk galaxies, NGC 4565 and NGC 5907, using the Spitzer high-resolution infrared spectrograph. The 0-0 S(0) 28.2 {mu}m and 0-0 S(1) 17.0 {mu}m pure rotational lines were detected out to 10 kpc from the center of each galaxy on both sides of the major axis, and in NGC 4565 the S(0) line was detected at r = 15 kpc on one side. This location is beyond the transition zone where diffuse neutral atomic hydrogen starts to dominate over cold molecular gas and marks a transition from a disk dominated by high surface-brightness far-infrared (far-IR) emission to that of a more quiescent disk. It also lies beyond a steep drop in the radio continuum emission from cosmic rays (CRs) in the disk. Despite indications that star formation activity decreases with radius, the H{sub 2} excitation temperature and the ratio of the H{sub 2} line and the far-IR luminosity surface densities, {Sigma}(L{sub H{sub 2}})/{Sigma}(L{sub TIR}), change very little as a function of radius, even into the diffuse outer region of the disk of NGC 4565. This suggests that the source of excitation of the H{sub 2} operates over a large range of radii and is broadly independent of the strength and relative location of UV emission from young stars. Although excitation in photodissociation regions is the most common explanation for the widespread H{sub 2} emission, CR heating or shocks cannot be ruled out. At r = 15 kpc in NGC 4565, outside the main UV- and radio-continuum-dominated disk, we derived a higher than normal H{sub 2} to 7.7 {mu}m polycyclic aromatic hydrocarbon (PAH) emission ratio, but this is likely due to a transition from mainly ionized PAH molecules in the inner disk to mainly neutral PAH molecules in the outer disk. The inferred mass surface densities of warm molecular hydrogen in both edge-on galaxies differ substantially, being 4(-60) M{sub sun} pc{sup -2} and 3(-50) M{sub sun} pc{sup -2} at r = 10 kpc for NGC 4565 and NGC 5907

  4. SU-E-J-49: Distal Edge Activity Fall Off Of Proton Therapy Beams

    SciTech Connect (OSTI)

    Elmekawy, A; Ewell, L; Butuceanu, C; Zhu, L

    2014-06-01

    Purpose: To characterize and quantify the distal edge activity fall off, created in a phantom by a proton therapy beam Method and Materials: A 30x30x10cm polymethylmethacrylate phantom was irradiated with a proton therapy beam using different ranges and beams. The irradiation volume is approximated by a right circular cylinder of diameter 7.6cm and varying lengths. After irradiation, the phantom was scanned via a Philips Gemini Big Bore™ PET-CT for isotope activation. Varian Eclipse™ treatment planning system as well as ImageJ™ were used to analyze the resulting PET and CT scans. The region of activity within the phantom was longitudinally measured as a function of PET slice number. Dose estimations were made via Monte Carlo (GATE) simulation. Results: For both the spread out Bragg peak (SOBP) and the mono-energetic pristine Bragg peak proton beams, the proximal activation rise was steep: average slope −0.735 (average intensity/slice number) ± 0.091 (standard deviation) for the pristine beams and −1.149 ± 0.117 for the SOBP beams. In contrast, the distal fall offs were dissimilar. The distal fall off in activity for the pristine beams was fit well by a linear curve: R{sup 2} (Pierson Product) was 0.9968, 0.9955 and 0.9909 for the 13.5, 17.0 and 21.0cm range beams respectively. The good fit allows for a slope comparison between the different ranges. The slope varied as a function of range from 1.021 for the 13.5cm beam to 0.8407 (average intensity/slice number) for the 21.0cm beam. This dependence can be characterized: −0.0234(average intensity/slice number/cm range). For the SOBP beams, the slopes were significantly less and were also less linear: average slope 0.2628 ± 0.0474, average R{sup 2}=0.9236. Conclusion: The distal activation fall off edge for pristine proton beams was linear and steep. The corresponding quantities for SOBP beams were shallower and less linear. Philips has provided support for this work.

  5. Towards identifying the mechanisms underlying field-aligned edge-loss of HHFW power on NSTX

    SciTech Connect (OSTI)

    Perkins, R. J.; Bell, R. E.; Bertelli, N.; Diallo, A.; Gerhardt, S.; Hosea, J. C.; Jaworski, M. A.; LeBlanc, B. P.; Kramer, G. J.; Maingi, R.; Phillips, C. K.; Podestà, M.; Roquemore, L.; Scotti, F.; Taylor, G.; Wilson, J. R.; Ahn, J-W.; Gray, T. K.; Green, D. L.; McLean, A.; and others

    2014-02-12

    Fast-wave heating will be a major heating scheme on ITER, as it can heat ions directly and is relatively unaffected by the large machine size unlike neutral beams. However, fast-wave interactions with the plasma edge can lead to deleterious effects such as, in the case of the high-harmonic fast-wave (HHFW) system on NSTX, large losses of fast-wave power in the scrape off layer (SOL) under certain conditions. In such scenarios, a large fraction of the lost HHFW power is deposited on the upper and lower divertors in bright spiral shapes. The responsible mechanism(s) has not yet been identified but may include fast-wave propagation in the scrape off layer, parametric decay instability, and RF currents driven by the antenna reactive fields. Understanding and mitigating these losses is important not only for improving the heating and current-drive on NSTX-Upgrade but also for understanding fast-wave propagation across the SOL in any fast-wave system. This talk summarizes experimental results demonstrating that the flow of lost HHFW power to the divertor regions largely follows the open SOL magnetic field lines. This lost power flux is relatively large close to both the antenna and the last closed flux surface with a reduced level in between, so the loss mechanism cannot be localized to the antenna. At the same time, significant losses also occur along field lines connected to the inboard edge of the bottom antenna plate. The power lost within the spirals is roughly estimated, showing that these field-aligned losses to the divertor are significant but may not account for the total HHFW loss. To elucidate the role of the onset layer for perpendicular fast-wave propagation with regards to fast-wave propagation in the SOL, a cylindrical cold-plasma model is being developed. This model, in addition to advanced RF codes such as TORIC and AORSA, is aimed at identifying the underlying mechanism(s) behind these SOL losses, to minimize their effects in NSTX-U, and to predict

  6. Gyro-fluid and two-fluid theory and simulations of edge-localized-modes

    SciTech Connect (OSTI)

    Xu, X. Q.; Dimits, A.; Joseph, I.; Umansky, M. V.; Xi, P. W.; School of Physics, Peking University, Beijing ; Xia, T. Y.; Gui, B.; Institute of Plasma Physics, Chinese Academy of Sciences, Hefei ; Kim, S. S.; Park, G. Y.; Rhee, T.; Jhang, H.; Diamond, P. H.; Center for Astrophysics and Space Sciences and Department of Physics, University of California, San Diego, La Jolla, California 92093-0424 ; Dudson, B.; Snyder, P. B.

    2013-05-15

    This paper reports on the theoretical and simulation results of a gyro-Landau-fluid extension of the BOUT++ code, which contributes to increasing the physics understanding of edge-localized-modes (ELMs). Large ELMs with low-to-intermediate-n peeling-ballooning (P-B) modes are significantly suppressed due to finite Larmor radius (FLR) effects when the ion temperature increases. For type-I ELMs, it is found from linear simulations that retaining complete first order FLR corrections as resulting from the incomplete “gyroviscous cancellation” in Braginskii's two-fluid model is necessary to obtain good agreement with gyro-fluid results for high ion temperature cases (T{sub i}≽3 keV) when the ion density has a strong radial variation, which goes beyond the simple local model of ion diamagnetic stabilization of ideal ballooning modes. The maximum growth rate is inversely proportional to T{sub i} because the FLR effect is proportional to T{sub i}. The FLR effect is also proportional to toroidal mode number n, so for high n cases, the P-B mode is stabilized by FLR effects. Nonlinear gyro-fluid simulations show results that are similar to those from the two-fluid model, namely that the P-B modes trigger magnetic reconnection, which drives the collapse of the pedestal pressure. Due to the additional FLR-corrected nonlinear E × B convection of the ion gyro-center density, for a ballooning-dominated equilibrium the gyro-fluid model further limits the radial spreading of ELMs. In six-field two fluid simulations, the parallel thermal diffusivity is found to prevent the ELM encroachment further into core plasmas and therefore leads to steady state L-mode profiles. The simulation results show that most energy is lost via ion channel during an ELM event, followed by particle loss and electron energy loss. Because edge plasmas have significant spatial inhomogeneities and complicated boundary conditions, we have developed a fast non-Fourier method for the computation of Landau

  7. Public Data Set: High Confinement Mode and Edge Localized Mode Characteristics in a Near-Unity Aspect Ratio Tokamak

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Thome, Kathreen E. [University of Wisconsin-Madison] (ORCID:0000000248013922); Bongard, Michael W. [University of Wisconsin-Madison] (ORCID:0000000231609746); Barr, Jayson L. [University of Wisconsin-Madison] (ORCID:0000000177685931); Bodner, Grant M. [University of Wisconsin-Madison] (ORCID:0000000324979172); Burke, Marcus G. [University of Wisconsin-Madison] (ORCID:0000000176193724); Fonck, Raymond J. [University of Wisconsin-Madison] (ORCID:0000000294386762); Kriete, David M. [University of Wisconsin-Madison] (ORCID:0000000236572911); Perry, Justin M. [University of Wisconsin-Madison] (ORCID:0000000171228609); Schlossberg, David J. [University of Wisconsin-Madison] (ORCID:0000000287139448)

    2016-04-27

    This data set contains openly-documented, machine readable digital research data corresponding to figures published in K.E. Thome et al., 'High Confinement Mode and Edge Localized Mode Characteristics in a Near-Unity Aspect Ratio Tokamak,' Phys. Rev. Lett. 116, 175001 (2016).

  8. The effect of rotation and viscous heating on the interpretation of experimental heat diffusivities in the edge pedestal

    SciTech Connect (OSTI)

    Stacey, Weston M.

    2010-05-15

    A formalism is presented for evaluating the effect of plasma rotation, via viscous heating, on the interpretation of thermal conductivities from measured temperature and density gradients in the edge pedestal. An application to a H-mode DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] discharge indicates that the effect could be significant.

  9. Simulations of drift resistive ballooning L-mode turbulence in the edge plasma of the DIII-D tokamak

    SciTech Connect (OSTI)

    Cohen, B. I.; Umansky, M. V.; Nevins, W. M.; Makowski, M. A.; Boedo, J. A.; Rudakov, D. L.; McKee, G. R.; Yan, Z.; Groebner, R. J.

    2013-05-15

    Results from simulations of electromagnetic drift-resistive ballooning turbulence for tokamak edge turbulence in realistic single-null geometry are reported. The calculations are undertaken with the BOUT three-dimensional fluid code that solves Braginskii-based fluid equations [X. Q. Xu and R. H. Cohen, Contrib. Plasma Phys. 36, 158 (1998)]. The simulation setup models L-mode edge plasma parameters in the actual magnetic geometry of the DIII-D tokamak [J. L. Luxon et al., Fusion Sci. Technol. 48, 807 (2002)]. The computations track the development of drift-resistive ballooning turbulence in the edge region to saturation. Fluctuation amplitudes, fluctuation spectra, and particle and thermal fluxes are compared to experimental data near the outer midplane from Langmuir probe and beam-emission-spectroscopy for a few well-characterized L-mode discharges in DIII-D. The simulations are comprised of a suite of runs in which the physics model is varied to include more fluid fields and physics terms. The simulations yield results for fluctuation amplitudes, correlation lengths, particle and energy fluxes, and diffusivities that agree with measurements within an order of magnitude and within factors of 2 or better for some of the data. The agreement of the simulations with the experimental measurements varies with respect to including more physics in the model equations within the suite of models investigated. The simulations show stabilizing effects of sheared E B poloidal rotation (imposed zonal flow) and of lower edge electron temperature and density.

  10. Atomic-scale investigation of point defects and hydrogen-solute atmospheres on the edge dislocation mobility in alpha iron

    SciTech Connect (OSTI)

    Bhatia, M. A.; Solanki, K. N.; Groh, S.

    2014-08-14

    In this study, we present atomistic mechanisms of 1/2 [111](11{sup }0) edge dislocation interactions with point defects (hydrogen and vacancies) and hydrogen solute atmospheres in body centered cubic (bcc) iron. In metals such as iron, increases in hydrogen concentration can increase dislocation mobility and/or cleavage-type decohesion. Here, we first investigate the dislocation mobility in the presence of various point defects, i.e., change in the frictional stress as the edge dislocation interacts with (a) vacancy, (b) substitutional hydrogen, (c) one substitutional and one interstitial hydrogen, (d) interstitial hydrogen, (e) vacancy and interstitial hydrogen, and (f) two interstitial hydrogen. Second, we examine the role of a hydrogen-solute atmosphere on the rate of local dislocation velocity. The edge dislocation simulation with a vacancy in the compression side of the dislocation and an interstitial hydrogen atom at the tension side exhibit the strongest mechanical response, suggesting a higher potential barrier and hence, the higher frictional stress (i.e., ?83% higher than the pure iron Peierls stress). In the case of a dislocation interacting with a vacancy on the compressive side, the vacancy binds with the edge dislocation, resulting in an increase in the friction stress of about 28% when compared with the Peierls stress of an edge dislocation in pure iron. Furthermore, as the applied strain increases, the vacancy migrates through a dislocation transportation mechanism by attaining a velocity of the same order as the dislocation velocity. For the case of the edge dislocation interacting with interstitial hydrogen on the tension side, the hydrogen atom jumps through one layer perpendicular to the glide plane during the pinning-unpinning process. Finally, our simulation of dislocation interactions with hydrogen show first an increase in the local dislocation velocity followed by a pinning of the dislocation core in the atmosphere, resulting in resistance

  11. Casimir-Polder repulsion near edges: Wedge apex and a screen with an aperture

    SciTech Connect (OSTI)

    Milton, Kimball A.; Abalo, E. K.; Parashar, Prachi; Pourtolami, Nima; Brevik, Iver; Ellingsen, Simen A.

    2011-06-15

    Although repulsive effects have been predicted for quantum vacuum forces between bodies with nontrivial electromagnetic properties, such as between a perfect electric conductor and a perfect magnetic conductor, realistic repulsion seems difficult to achieve. Repulsion is possible if the medium between the bodies has a permittivity in value intermediate to those of the two bodies, but this may not be a useful configuration. Here, inspired by recent numerical work, we initiate analytic calculations of the Casimir-Polder interaction between an atom with anisotropic polarizability and a plate with an aperture. In particular, for a semi-infinite plate, and, more generally, for a wedge, the problem is exactly solvable, and for sufficiently large anisotropy, Casimir-Polder repulsion is indeed possible, in agreement with the previous numerical studies. In order to achieve repulsion, what is needed is a sufficiently sharp edge (not so very sharp, in fact) so that the directions of polarizability of the conductor and the atom are roughly normal to each other. The machinery for carrying out the calculation with a finite aperture is presented. As a motivation for the quantum calculation, we carry out the corresponding classical analysis for the force between a dipole and a metallic sheet with a circular aperture, when the dipole is on the symmetry axis and oriented in the same direction.

  12. Ab initio study of semiconductor atoms impurities in zigzag edge (10,0) carbon nanotubes

    SciTech Connect (OSTI)

    Muttaqien, Fahdzi Suprijadi

    2015-04-16

    The substitutional impurities in zigzag edge (10,0) carbon nanotubes have been studied by using first principles calculations. Silicon (Si), gallium (Ga), and arsenic (As) atom have been chosen as semiconductor based-atom for replacing carbon atoms in CNTs surface. The silicon atom changes the energy gap of pristine zigzag (10,0) CNT, it is 0.19 eV more narrow than that of pristine CNT. Geometrically, the silicon atom creates sp{sup 3} bond with three adjacent carbon atoms, where the tetrahedral form of its sp{sup 3} bond is consisted of free unoccupied state. The silicon atom does not induce magnetism to zigzag CNT. Due to gallium (Ga) and arsenic (As) atom substitution, the zigzag CNT becomes metallic and has magnetic moment of 1?{sub B}. The valance and conduction band are crossed each other, then the energy gap is vanished. The electronic properties of GaAs-doped CNT are dominantly affected by gallium atom and its magnetic properties are dominantly affected by arsenic atom. These results prove that the CNT with desired properties can be obtained with substitutional impurities without any giving structural defect.

  13. Near-Edge X-Ray Absorption Fine Structure Spectroscopy of Diamondoid Thiol Monolayers on Gold

    SciTech Connect (OSTI)

    Willey, T.M.; Fabbri, J.D.; Lee, J.R.I.; Schreiner, P.R.; Fokin, A.A.; Tkachenko, B.A.; Fokina, N.A.; Dahl, J.E.P.; Carlson, R.M.K.; Vance, A.L.; Yang, W.; Terminello, L.J.; Buuren, T.van; Melosh, N.A.

    2009-05-26

    Diamondoids, hydrocarbon molecules with cubic-diamond-cage structures, have unique properties with potential value for nanotechnology. The availability and ability to selectively functionalize this special class of nanodiamond materials opens new possibilities for surface modification, for high-efficiency field emitters in molecular electronics, as seed crystals for diamond growth, or as robust mechanical coatings. The properties of self-assembled monolayers (SAMs) of diamondoids are thus of fundamental interest for a variety of emerging applications. This paper presents the effects of thiol substitution position and polymantane order on diamondoid SAMs on gold using near-edge X-ray absorption fine structure spectroscopy (NEXAFS) and X-ray photoelectron spectroscopy (XPS). A framework to determine both molecular tilt and twist through NEXAFS is presented and reveals highly ordered diamondoid SAMs, with the molecular orientation controlled by the thiol location. C 1s and S 2p binding energies are lower in adamantane thiol than alkane thiols on gold by 0.67 {+-} 0.05 and 0.16 {+-} 0.04 eV, respectively. These binding energies vary with diamondoid monolayer structure and thiol substitution position, consistent with different degrees of steric strain and electronic interaction with the substrate. This work demonstrates control over the assembly, in particular the orientational and electronic structure, providing a flexible design of surface properties with this exciting new class of diamond nanoparticles.

  14. Near-Edge X-ray Absorption Fine Structure Spectroscopy of Diamondoid Thiol Monolayers on Gold

    SciTech Connect (OSTI)

    Willey, T M; Fabbri, J; Lee, J I; Schreiner, P; Fokin, A A; Tkachenko, B A; Fokina, N A; Dahl, J; Carlson, B; Vance, A L; Yang, W; Terminello, L J; van Buuren, T; Melosh, N

    2007-11-27

    Diamondoids, hydrocarbon molecules with cubic-diamond-cage structures, have unique properties with potential value for nanotechnology. The availability and ability to selectively functionalize this special class of nanodiamond materials opens new possibilities for surface-modification, for high-efficiency field emitters in molecular electronics, as seed crystals for diamond growth, or as robust mechanical coatings. The properties of self-assembled monolayers (SAMs) of diamondoids are thus of fundamental interest for a variety of emerging applications. This paper presents the effects of thiol substitution position and polymantane order on diamondoid SAMs on gold using near-edge X-ray absorption fine structure spectroscopy (NEXAFS) and X-ray photoelectron spectroscopy (XPS). A framework to determine both molecular tilt and twist through NEXAFS is presented and reveals highly ordered diamondoid SAMs, with the molecular orientation controlled by the thiol location. C 1s and S 2p binding energies are lower in adamantane thiol than alkane thiols on gold by 0.67 {+-} 0.05 eV and 0.16 {+-} 0.04 eV respectively. These binding energies vary with diamondoid monolayer structure and thiol substitution position, consistent with different amounts of steric strain and electronic interaction with the substrate. This work demonstrates control over the assembly, in particular the orientational and electronic structure, providing a flexible design of surface properties with this exciting new class of diamond clusters.

  15. Intrinsic plasma rotation and Reynolds stress at the plasma edge in the HSX stellarator

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wilcox, Robert S.; Talmadge, J. N.; Anderson, David T.; F. S. B. Anderson; Lore, Jeremy D.

    2016-02-05

    Using multi-tipped Langmuir probes in the edge of the HSX stellarator, the radial electric field and parallel flows are found to deviate from the values calculated by the neoclassical transport code PENTA for the optimized quasi-helically symmetric (QHS) configuration. To understand whether Reynolds stress might explain the discrepancy, fluctuating floating potential measurements are made at two locations in the torus corresponding to the low field and high field sides of the device. The measurements at the two locations show clear evidence of a gradient in the Reynolds stress. However, the resulting flow due to the gradient in the stress ismore » found to be large and in opposite directions for the two locations. This makes an estimation of the flux surface average using a small number of measurement locations impractical from an experimental perspective. These results neither confirm nor rule out whether Reynolds stress plays an important role for the QHS configuration. Measurements made in configurations with the quasi-symmetry degraded show even larger flows and greater deviations from the neoclassically calculated velocity profiles than the QHS configuration while the fluctuation magnitudes are reduced. Lastly, for these configurations in particular, the Reynolds stress is most likely not responsible for the additional momentum.« less

  16. Characterization of a Messer – The late-Medieval single-edged sword of Central Europe

    SciTech Connect (OSTI)

    Fajfar, Peter; Medved, Jožef; Klančnik, Grega; Lazar, Tomaž; Nečemer, Marijan; Mrvar, Primož

    2013-12-15

    Metallurgical characterization of a sword blade fragments dating from the second half of the 15th century found in central Slovenia was performed in order to determine its chemical composition, microstructure, microhardness, and to obtain insight into the methods of manufacture of a late-medieval Messer sword. As the artefact was broken, examinations were limited to six very small fragments that were allowed to be removed from the cutting edge, core and the back of the blade. Light optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, energy dispersive X-ray fluorescence spectrometry, differential scanning calorimetry, thermodynamics approach and Vickers micro-hardness tests were employed to analyze the microstructure and mechanical properties. The results show that the sword was manufactured from a single wrought iron billet. The surface of the sword was carburized. No evidence of quenching was found. The ferritic microstructure is concentrated in the core, and the pearlitic in the outer layer of the blade. All metal fragments contained non-metallic inclusions that were derived mostly from slag and some from hammer scale. - Highlights: • A metallurgical characterization of a medieval sword blade has been performed. • The carbon content decreased from the surface to the core of the blade. • The dominant microstructure in the outer layer is pearlite and in the core is ferrite. • The presence of lump shaped and elongated non-metallic inclusions was observed. • The sword was manufactured from a single wrought iron billet.

  17. Vertical GaN power diodes with a bilayer edge termination

    SciTech Connect (OSTI)

    Dickerson, Jeramy R.; Allerman, Andrew A.; Bryant, Benjamin N.; Fischer, Arthur J.; King, Michael P.; Moseley, Michael W.; Armstrong, Andrew M.; Kaplar, Robert J.; Kizilyalli, Isik C.; Aktas, Ozgur; Wierer, Jr., Jonathan J.

    2015-12-07

    Vertical GaN power diodes with a bilayer edge termination (ET) are demonstrated. The GaN p-n junction is formed on a low threading dislocation defect density (104 - 105 cm-2) GaN substrate, and has a 15-μm-thick n-type drift layer with a free carrier concentration of 5 × 1015 cm-3. The ET structure is formed by N implantation into the p+-GaN epilayer just outside the p-type contact to create compensating defects. The implant defect profile may be approximated by a bilayer structure consisting of a fully compensated layer near the surface, followed by a 90% compensated (p) layer near the n-type drift region. These devices exhibit avalanche breakdown as high as 2.6 kV at room temperature. In addition simulations show that the ET created by implantation is an effective way to laterally distribute the electric field over a large area. This increases the voltage at which impact ionization occurs and leads to the observed higher breakdown voltages.

  18. Vertical GaN power diodes with a bilayer edge termination

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dickerson, Jeramy R.; Allerman, Andrew A.; Bryant, Benjamin N.; Fischer, Arthur J.; King, Michael P.; Moseley, Michael W.; Armstrong, Andrew M.; Kaplar, Robert J.; Kizilyalli, Isik C.; Aktas, Ozgur; et al

    2015-12-07

    Vertical GaN power diodes with a bilayer edge termination (ET) are demonstrated. The GaN p-n junction is formed on a low threading dislocation defect density (104 - 105 cm-2) GaN substrate, and has a 15-μm-thick n-type drift layer with a free carrier concentration of 5 × 1015 cm-3. The ET structure is formed by N implantation into the p+-GaN epilayer just outside the p-type contact to create compensating defects. The implant defect profile may be approximated by a bilayer structure consisting of a fully compensated layer near the surface, followed by a 90% compensated (p) layer near the n-type driftmore » region. These devices exhibit avalanche breakdown as high as 2.6 kV at room temperature. In addition simulations show that the ET created by implantation is an effective way to laterally distribute the electric field over a large area. This increases the voltage at which impact ionization occurs and leads to the observed higher breakdown voltages.« less

  19. Molecular anisotropy effects in carbon K-edge scattering: depolarized diffuse scattering and optical anisotropy

    SciTech Connect (OSTI)

    Stone, Kevin H.

    2014-07-14

    Some polymer properties, such as conductivity, are very sensitive to short- and intermediate-range orientational and positional ordering of anisotropic molecular functional groups, and yet means to characterize orientational order in disordered systems are very limited. We demonstrate that resonant scattering at the carbon K-edge is uniquely sensitive to short-range orientation correlations in polymers through depolarized scattering at high momentum transfers, using atactic polystyrene as a well-characterized test system. Depolarized scattering is found to coexist with unpolarized fluorescence, and to exhibit pronounced anisotropy. We also quantify the spatially averaged optical anisotropy from low-angle reflectivity measurements, finding anisotropy consistent with prior visible, x-ray absorption, and theoretical studies. The average anisotropy is much smaller than that in the depolarized scattering and the two have different character. Both measurements exhibit clear spectral signatures from the phenyl rings and the polyethylene-like backbone. Discussion focuses on analysis considerations and prospects for using this depolarized scattering for studies of disorder in soft condensed matter.

  20. Numerical study of transition to supersonic flows in the edge plasma

    SciTech Connect (OSTI)

    Goswami, Rajiv, E-mail: rajiv@ipr.res.in; Artaud, Jean-Franois; Imbeaux, Frdric [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Kaw, Predhiman [Institute for Plasma Research, Bhat, Gandhinagar382428 (India)

    2014-07-15

    The plasma scrape-off layer (SOL) in a tokamak is characterized by ion flow down a long narrow flux tube terminating on a solid surface. The ion flow velocity along a magnetic field line can be equal to or greater than sonic at the entrance of a Debye sheath or upstream in the presheath. This paper presents a numerical study of the transition between subsonic and supersonics flows. A quasineutral one-dimensional (1D) fluid code has been used for modeling of plasma transport in the SOL along magnetic field lines, both in steady state and under transient conditions. The model uses coupled equations for continuity, momentum, and energy balance with ionization, radiation, charge exchange, and recombination processes. The recycled neutrals are described in the diffusion approximation. Standard Bohm sheath criterion is used as boundary conditions at the material surface. Three conditions conducive for the generation of supersonic flows in SOL plasmas have been explored. It is found that in steady state high (attached) and low (detached) divertor temperatures cases, the role of particle, momentum, and energy loss is critical. For attached case, the appearance of shock waves in the divertor region if the incoming plasma flow is supersonic and its effect on impurity retention is presented. In the third case, plasma expansion along the magnetic field can yield time-dependent supersonic solutions in the quasineutral rarefaction wave. Such situations can arise in the parallel transport of intermittent structures such as blobs and edge localized mode filaments along field lines.

  1. Thin planar package for cooling an array of edge-emitting laser diodes

    DOE Patents [OSTI]

    Mundinger, David C.; Benett, William J.

    1992-01-01

    A laser diode array is disclosed that includes a plurality of planar assemblies and active cooling of each assembly. The laser diode array may be operated in a long duty cycle, or in continuous operation. A laser diode bar and a microchannel heat sink are thermally coupled in a compact, thin planar assembly having the laser diode bar located proximate to one edge. In an array, a number of such thin planar assemblies are secured together in a stacked configuration, in close proximity so that the laser diodes are spaced closely. The cooling means includes a microchannel heat sink proximate to the laser diode bar to absorb heat generated by laser operation. To provide the coolant to the microchannels, each thin planar assembly comprises passageways that connect the microchannels to inlet and outlet corridors. Each inlet passageway may comprise a narrow slot that directs coolant into the microchannels and increases the velocity of flow therethrough. The corridors comprises holes extending through each of the assemblies in the array. The inlet and outlet corridors are connected to a conventional coolant circulation system. The laser diode array with active cooling has applications as an optical pump for high power solid state lasers, or by mating the diodes with fiber optic lenses. Further, the arrays can be useful in applications having space constraints and energy limitations, and in military and space applications. The arrays can be incorporated in equipment such as communications devices and active sensors.

  2. Implementation of the 3D edge plasma code EMC3-EIRENE on NSTX

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lore, J. D.; Canik, J. M.; Feng, Y.; Ahn, J. -W.; Maingi, R.; Soukhanovskii, V.

    2012-05-09

    The 3D edge transport code EMC3-EIRENE has been applied for the first time to the NSTX spherical tokamak. A new disconnected double null grid has been developed to allow the simulation of plasma where the radial separation of the inner and outer separatrix is less than characteristic widths (e.g. heat flux width) at the midplane. Modelling results are presented for both an axisymmetric case and a case where 3D magnetic field is applied in an n = 3 configuration. In the vacuum approximation, the perturbed field consists of a wide region of destroyed flux surfaces and helical lobes which aremore » a mixture of long and short connection length field lines formed by the separatrix manifolds. This structure is reflected in coupled 3D plasma fluid (EMC3) and kinetic neutral particle (EIRENE) simulations. The helical lobes extending inside of the unperturbed separatrix are filled in by hot plasma from the core. The intersection of the lobes with the divertor results in a striated flux footprint pattern on the target plates. As a result, profiles of divertor heat and particle fluxes are compared with experimental data, and possible sources of discrepancy are discussed.« less

  3. A rigorous simulation study of water coning and edge water encroachment using a sector model

    SciTech Connect (OSTI)

    Bu-Hulaigah, E.H.; Rabbani, G.; Lin, C.; Al-Khowaiter, A.O.

    1995-11-01

    A simulation study was conducted in a shaly sandstone reservoir to study field observed coning behavior of a single well and recommend an optimum production rate for its sustained operation. The simulation model covers a 13 km by 5 km area to enable simultaneous simulation of individual well coning and regional edge water encroachment. The effect of areal grid size on matching the observed coning behavior was investigated using Local Refined Grid (LRG). A 20-meter LRG model was chosen to perform various prediction cases to determine the optimum production rate for the coning well. The model was also used to investigate development options to accelerate the recovery of downdip oil, where a 50 feet shallower oil-water contact is observed. This study shows the utility of sector models to study individual well coning behavior and optimize production rate restrictions due to coning, where the regional oil-water contact is dynamic. Conventional single well radial models are considered inappropriate in such cases.

  4. Soil and fertilizer amendments and edge effects on the floral succession of pulverized fuel ash

    SciTech Connect (OSTI)

    Shaw, P.

    2009-01-15

    Plots of fresh pulverized fuel ash (PFA, an industrial waste) were inoculated with soils from existing PFA sites and fertilizers in a factorial design, then left unmanaged for 12 years during which time the floral development and soil chemistry were monitored annually. For the first 3 years, the site supported a sparse mix of chenopods (including the scarce Chenopodium glaucum) and halophytes. As salinity declined, ruderals, legumes, and grasses plus the fire-site moss Funaria hygrometrica colonized, followed by Festuca arundinacea grassland (NVC community MG12) and Hippophae rhamnoides scrub. Dactylorhiza incarnata (orchidacea) appeared after 7 years, but only in plots that had received soil from existing orchid colonies. Four years later, a larger second generation of Dactylorhiza appeared, but only in the central zone of the site where vegetation was thinnest. By year 12, the site was dominated by coarse grasses and scrub, with early successional species persisting only in the sparsely vegetated center, where nitrate levels were lowest. This edge effect is interpreted as centripetal encroachment, a process of potentially wider concern for the conservation of low-fertility habitat patches. Overall, seed bank inoculation seems to have introduced few but desirable species (D. incarnata, Pyrola rotundifolia, some halophytes, and annuals), whereas initial application of organic fertilizer had long-lasting ({ge} 10 years) effects on cover and soil composition.

  5. Exterior Rigid Foam Insulation at the Edge of a Slab Foundation, Fresno, California (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2013-10-01

    Exterior rigid foam insulation at the edge of the slab foundation was a unique feature for this low-load, unoccupied test house in a hot-dry climate and may be more appropriate for climates with higher heating loads. U.S. Department of Energy Building America research team IBACOS worked with National Housing Quality Award winner Wathen-Castanos Hybrid Homes, Inc., to assess the performance of this feature in a single-family detached ranch house with three bedrooms and two full bathrooms constructed on a slab-on-grade foundation in Fresno, California. One challenge during installation of the system was the attachment of the butyl flashing to the open framing. To solve this constructability issue, the team added a nailer to the base of the wall to properly attach and lap the flashing. In this strategy, R-7.5, 1.5-in.-thick extruded polystyrene was installed on the exterior of the slab for a modeled savings of 4,500 Btu/h on the heating load.

  6. Final Report for Project "Framework Application for Core-Edge Transport Simulations (FACETS)"

    SciTech Connect (OSTI)

    Estep, Donald

    2014-01-17

    This is the final report for the Colorado State University Component of the FACETS Project. FACETS was focused on the development of a multiphysics, parallel framework application that could provide the capability to enable whole-device fusion reactor modeling and, in the process, the development of the modeling infrastructure and computational understanding needed for ITER. It was intended that FACETS be highly flexible, through the use of modern computational methods, including component technology and object oriented design, to facilitate switching from one model to another for a given aspect of the physics, and making it possible to use simplified models for rapid turnaround or high-fidelity models that will take advantage of the largest supercomputer hardware. FACETS was designed in a heterogeneous parallel context, where different parts of the application can take advantage through parallelism based on task farming, domain decomposition, and/or pipelining as needed and applicable. As with all fusion simulations, an integral part of the FACETS project was treatment of the coupling of different physical processes at different scales interacting closely. A primary example for the FACETS project is the coupling of existing core and edge simulations, with the transport and wall interactions described by reduced models. However, core and edge simulations themselves involve significant coupling of different processes with large scale differences. Numerical treatment of coupling is impacted by a number of factors including, scale differences, form of information transferred between processes, implementation of solvers for different codes, and high performance computing concerns. Operator decomposition involving the computation of the individual processes individually using appropriate simulation codes and then linking/synchronizing the component simulations at regular points in space and time, is the defacto approach to high performance simulation of multiphysics

  7. Late Mesozoic crustal extension and rifting on the western edge of the Parana Basin, Paraguay

    SciTech Connect (OSTI)

    DeGraff, J.M.

    1985-01-01

    Geophysical and geological evidence indicates that the western edge of the Parana basin in Paraguay was a site of NE-SW directed crustal extension during late Mesozoic time. Major zones of normal faulting in south-eastern Paraguay trend northwesterly on average, and mafic dikes of probable late Mesozoic age have similar orientations. At least two NW-trending zones of tectonic subsidence, each over 200 km long, are now recognized in eastern Paraguay. Most alkalic rocks of south-eastern Paraguay are concentrated along this rift, and occur as simple to composite stocks and ring complexes composed of rocks ranging from foid-syenite to essexite. NW-trending, lamprophyric to phonolitic dikes are associated with some alkalic complexes. The southern zone, located about 125 km southwest, is a composite tectonic basin about 60 km wide and nearly devoid of alkalic rocks. The timing of crustal extension and rifting in eastern Paraguay is largely based on isotopic ages of associated alkalic rocks, which cluster between 150 and 100 Ma (latest Jurassic to mid-Cretaceous). Geologic evidence for the age of faulting and subsidence is consistent with this age range; tectonic depressions were being filled in late Cretaceous to early Cenozoic time. The age range of alkalic rocks in Paraguay contain that of the Serra Geral basalts and spans the time when South America Separated from Africa. This suggests that alkalic activity and crustal extension in eastern Paraguay are grossly related to the Serra Geral extrusive event, and were a manifestation of the breakup of South America and Africa far from the site of final separation.

  8. Ventilation efficiencies and thermal comfort results of a desk-edge-mounted task ventilation system

    SciTech Connect (OSTI)

    Faulkner, D.; Fisk, W.J.; Sullivan, D.P.; Lee, S.M.

    2003-09-01

    In chamber experiments, we investigated the ventilation effectiveness and thermal comfort of a task ventilation system with an air supply nozzle located underneath the front edge of a desk and directing air toward a heated mannequin or a human volunteer seated at the desk. The task ventilation system provided outside air, while another ventilation system provided additional space cooling but no outside air. Test variables included the vertical angle of air supply (-15{sup o} to 45{sup o} from horizontal), and the supply flow rate of (3.5 to 6.5 L s{sup -1}). Using the tracer gas step-up and step-down procedures, the measured air change effectiveness (i.e., exhaust air age divided by age of air in the breathing zone) in experiments with the mannequin ranged from 1.4 to 2.7 (median, 1.8), whereas with human subjects the air change effectiveness ranged from 1.3 to 2.3 (median, 1.6). The majority of the air change effectiveness values with the human subjects were less than values with the mannequin at comparable tests. Similarly, the tests run with supply air temperature equal to the room air temperature had lower air change effectiveness values than comparable tests with the supply air temperature lower ({approx}5 C) than the room air temperature. The air change effectiveness values are higher than typically reported for commercially available task ventilation or displacement ventilation systems. Based on surveys completed by the subjects, operation of the task ventilation system did not cause thermal discomfort.

  9. SAND2008-1781

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Printed March 2008 Trailing Edge Modifications for Flatback Airfoils C.P. "Case" van Dam, and Daniel L. Kahn Department of Mechanical and Aeronautical Engineering University of ...

  10. SMART Wind Turbine Rotor: Design and Field Test

    Broader source: Energy.gov [DOE]

    Design and field test results from the SMART Rotor project, a wind turbine rotor with integrated trailing-edge flaps designed for active control of the rotor aerodynamics.

  11. A gyrokinetic one-dimensional scrape-off layer model of an edge-localized mode heat pulse

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Shi, E. L.; Hakim, A. H.; Hammett, G. W.

    2015-02-03

    An electrostatic gyrokinetic-based model is applied to simulate parallel plasma transport in the scrape-off layer to a divertor plate. We focus on a test problem that has been studied previously, using parameters chosen to model a heat pulse driven by an edge-localized mode in JET. Previous work has used direct particle-in-cellequations with full dynamics, or Vlasov or fluid equations with only parallel dynamics. With the use of the gyrokinetic quasineutrality equation and logical sheathboundary conditions, spatial and temporal resolution requirements are no longer set by the electron Debye length and plasma frequency, respectively. Finally, this test problem also helps illustratemore » some of the physics contained in the Hamiltonian form of the gyrokineticequations and some of the numerical challenges in developing an edge gyrokinetic code.« less

  12. Edge-facet pumped, multi-aperture, thin-disk laser geometry for very high average power output scaling

    DOE Patents [OSTI]

    Zapata, Luis E.

    2004-12-21

    The average power output of a laser is scaled, to first order, by increasing the transverse dimension of the gain medium while increasing the thickness of an index matched light guide proportionately. Strategic facets cut at the edges of the laminated gain medium provide a method by which the pump light introduced through edges of the composite structure is trapped and passes through the gain medium repeatedly. Spontaneous emission escapes the laser volume via these facets. A multi-faceted disk geometry with grooves cut into the thickness of the gain medium is optimized to passively reject spontaneous emission generated within the laser material, which would otherwise be trapped and amplified within the high index composite disk. Such geometry allows the useful size of the laser aperture to be increased, enabling the average laser output power to be scaled.

  13. Band edge engineering of oxide photoanodes for photoelectrochemical water splitting: Integration of subsurface dipoles with atomic-scale control

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hikita, Yasuyuki; Nishio, Kazunori; Seitz, Linsey C.; Chakthranont, Pongkarn; Tachikawa, Takashi; Jaramillo, Thomas F.; Hwang, Harold Y.

    2016-01-22

    One of the crucial parameters dictating the efficiency of photoelectrochemical water-splitting is the semiconductor band edge alignment with respect to hydrogen and oxygen redox potentials. Despite the importance of metal oxides in their use as photoelectrodes, studies to control the band edge alignment in aqueous solution have been limited predominantly to compound semiconductors with modulation ranges limited to a few hundred mV. The ability to modulate the flat band potential of oxide photoanodes by as much as 1.3 V, using the insertion of subsurface electrostatic dipoles near a Nb-doped SrTiO3/aqueous electrolyte interface is reported. Lastly, the tunable range achieved farmore » exceeds previous reports in any semiconductor/aqueous electrolyte system and suggests a general design strategy for highly efficient oxide photoelectrodes.« less

  14. L-connect routing of die surface pads to the die edge for stacking in a 3D array

    DOE Patents [OSTI]

    Petersen, Robert W.

    2000-01-01

    Integrated circuit chips and method of routing the interface pads from the face of the chip or die to one or more sidewall surfaces of the die. The interconnection is routed from the face of the die to one or more edges of the die, then routed over the edge of the die and onto the side surface. A new pad is then formed on the sidewall surface, which allows multiple die or chips to be stacked in a three-dimensional array, while enabling follow-on signal routing from the sidewall pads. The routing of the interconnects and formation of the sidewall pads can be carried out in an L-connect or L-shaped routing configuration, using a metalization process such as laser pantography.

  15. Time-resolved observation of discrete and continuous MHD dynamo in the reversed-field pinch edge

    SciTech Connect (OSTI)

    Ji, H.; Almagri, A.F.; Prager, S.C.; Sarff, J.S.

    1994-01-06

    We report the first experimental verification of the MHD dynamo in the RFP. A burst of magnetohydrodynamic (MHD) dynamo electric field is observed during the sawtooth crash, followed by an increase in the local parallel current in the MST RFP edge. By measuring each term, the parallel MHD mean-field Ohm`s law is observed to hold within experimental error bars both between and during sawtooth crashes.

  16. Gyrokinetic neoclassical study of the bootstrap current in the tokamak edge pedestal with fully non-linear Coulomb collisions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hager, Robert; Chang, C. S.

    2016-04-08

    As a follow-up on the drift-kinetic study of the non-local bootstrap current in the steep edge pedestal of tokamak plasma by Koh et al. [Phys. Plasmas 19, 072505 (2012)], a gyrokinetic neoclassical study is performed with gyrokinetic ions and drift-kinetic electrons. Besides the gyrokinetic improvement of ion physics from the drift-kinetic treatment, a fully non-linear Fokker-Planck collision operator—that conserves mass, momentum, and energy—is used instead of Koh et al.'s linearized collision operator in consideration of the possibility that the ion distribution function is non-Maxwellian in the steep pedestal. An inaccuracy in Koh et al.'s result is found in the steepmore » edge pedestal that originated from a small error in the collisional momentum conservation. The present study concludes that (1) the bootstrap current in the steep edge pedestal is generally smaller than what has been predicted from the small banana-width (local) approximation [e.g., Sauter et al., Phys. Plasmas 6, 2834 (1999) and Belli et al., Plasma Phys. Controlled Fusion 50, 095010 (2008)], (2) the plasma flow evaluated from the local approximation can significantly deviate from the non-local results, and (3) the bootstrap current in the edge pedestal, where the passing particle region is small, can be dominantly carried by the trapped particles in a broad trapped boundary layer. In conclusion, a new analytic formula based on numerous gyrokinetic simulations using various magnetic equilibria and plasma profiles with self-consistent Grad-Shafranov solutions is constructed.« less

  17. Plasma ionization frequency, edge-to-axis density ratio, and density on axis of a cylindrical gas discharge

    SciTech Connect (OSTI)

    Palacio Mizrahi, J. H.

    2014-06-15

    A rigorous derivation of expressions, starting from the governing equations, for the ionization frequency, edge-to-axis ratio of plasma density, plasma density at the axis, and radially averaged plasma density in a cylindrical gas discharge has been obtained. The derived expressions are simple and involve the relevant parameters of the discharge: Cylinder radius, axial current, and neutral gas pressure. The found expressions account for ion inertia, ion temperature, and changes in plasma ion collisionality.

  18. Wavy flow cooling concept for turbine airfoils

    DOE Patents [OSTI]

    Liang, George

    2010-08-31

    An airfoil including an outer wall and a cooling cavity formed therein. The cooling cavity includes a leading edge flow channel located adjacent a leading edge of the airfoil and a trailing edge flow channel located adjacent a trailing edge of the airfoil. Each of the leading edge and trailing edge flow channels define respective first and second flow axes located between pressure and suction sides of the airfoil. A plurality of rib members are located within each of the flow channels, spaced along the flow axes, and alternately extending from opposing sides of the flow channels to define undulating flow paths through the flow channels.

  19. Helical modulation of the electrostatic plasma potential due to edge magnetic islands induced by resonant magnetic perturbation fields at TEXTOR

    SciTech Connect (OSTI)

    Ciaccio, G. Spizzo, G.; Schmitz, O. Frerichs, H.; Abdullaev, S. S.; Evans, T. E.; White, R. B.

    2015-10-15

    The electrostatic response of the edge plasma to a magnetic island induced by resonant magnetic perturbations to the plasma edge of the circular limiter tokamak TEXTOR is analyzed. Measurements of plasma potential are interpreted by simulations with the Hamiltonian guiding center code ORBIT. We find a strong correlation between the magnetic field topology and the poloidal modulation of the measured plasma potential. The ion and electron drifts yield a predominantly electron driven radial diffusion when approaching the island X-point while ion diffusivities are generally an order of magnitude smaller. This causes a strong radial electric field structure pointing outward from the island O-point. The good agreement found between measured and modeled plasma potential connected to the enhanced radial particle diffusivities supports that a magnetic island in the edge of a tokamak plasma can act as convective cell. We show in detail that the particular, non-ambipolar drifts of electrons and ions in a 3D magnetic topology account for these effects. An analytical model for the plasma potential is implemented in the code ORBIT, and analyses of ion and electron radial diffusion show that both ion- and electron-dominated transport regimes can exist, which are known as ion and electron root solutions in stellarators. This finding and comparison with reversed field pinch studies and stellarator literature suggest that the role of magnetic islands as convective cells and hence as major radial particle transport drivers could be a generic mechanism in 3D plasma boundary layers.

  20. Edge-terminated molybdenum disulfide with a 9.4-Å interlayer spacing for electrochemical hydrogen production

    SciTech Connect (OSTI)

    Gao, Min -Rui; Chan, Maria K. Y.; Sun, Yugang

    2015-07-03

    In this study, layered molybdenum disulfide has demonstrated great promise as a low-cost alternative to platinum-based catalysts for electrochemical hydrogen production from water. Research effort on this material has focused mainly on synthesizing highly nanostructured molybdenum disulfide that allows the exposure of a large fraction of active edge sites. Here we report a promising microwave-assisted strategy for the synthesis of narrow molybdenum disulfide nanosheets with edge-terminated structure and a significantly expanded interlayer spacing, which exhibit striking kinetic metrics with onset potential of -103 mV, Tafel slope of 49 mV per decade and exchange current density of 9.62 × 10-3 mA cm-2, performing among the best of current molybdenum disulfide catalysts. Besides benefits from the edge-terminated structure, the expanded interlayer distance with modified electronic structure is also responsible for the observed catalytic improvement, which suggests a potential way to design newly advanced molybdenum disulfide catalysts through modulating the interlayer distance.

  1. Edge-terminated molybdenum disulfide with a 9.4-Å interlayer spacing for electrochemical hydrogen production

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gao, Min -Rui; Chan, Maria K. Y.; Sun, Yugang

    2015-07-03

    In this study, layered molybdenum disulfide has demonstrated great promise as a low-cost alternative to platinum-based catalysts for electrochemical hydrogen production from water. Research effort on this material has focused mainly on synthesizing highly nanostructured molybdenum disulfide that allows the exposure of a large fraction of active edge sites. Here we report a promising microwave-assisted strategy for the synthesis of narrow molybdenum disulfide nanosheets with edge-terminated structure and a significantly expanded interlayer spacing, which exhibit striking kinetic metrics with onset potential of -103 mV, Tafel slope of 49 mV per decade and exchange current density of 9.62 × 10-3 mAmore » cm-2, performing among the best of current molybdenum disulfide catalysts. Besides benefits from the edge-terminated structure, the expanded interlayer distance with modified electronic structure is also responsible for the observed catalytic improvement, which suggests a potential way to design newly advanced molybdenum disulfide catalysts through modulating the interlayer distance.« less

  2. Step-edge-induced resistance anisotropy in quasi-free-standing bilayer chemical vapor deposition graphene on SiC

    SciTech Connect (OSTI)

    Ciuk, Tymoteusz [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw (Poland); Cakmakyapan, Semih; Ozbay, Ekmel [Department of Electrical and Electronics Engineering, Department of Physics, Nanotechnology Research Center, Bilkent University, 06800 Bilkent, Ankara (Turkey); Caban, Piotr; Grodecki, Kacper; Pasternak, Iwona; Strupinski, Wlodek, E-mail: wlodek.strupinski@itme.edu.pl [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Krajewska, Aleksandra [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Institute of Optoelectronics, Military University of Technology, Gen. S. Kaliskiego 2, 00-908 Warsaw (Poland); Szmidt, Jan [Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw (Poland)

    2014-09-28

    The transport properties of quasi-free-standing (QFS) bilayer graphene on SiC depend on a range of scattering mechanisms. Most of them are isotropic in nature. However, the SiC substrate morphology marked by a distinctive pattern of the terraces gives rise to an anisotropy in graphene's sheet resistance, which may be considered an additional scattering mechanism. At a technological level, the growth-preceding in situ etching of the SiC surface promotes step bunching which results in macro steps ~10 nm in height. In this report, we study the qualitative and quantitative effects of SiC steps edges on the resistance of epitaxial graphene grown by chemical vapor deposition. We experimentally determine the value of step edge resistivity in hydrogen-intercalated QFS-bilayer graphene to be ~190 ??m for step height hS = 10 nm and provide proof that it cannot originate from mechanical deformation of graphene but is likely to arise from lowered carrier concentration in the step area. Our results are confronted with the previously reported values of the step edge resistivity in monolayer graphene over SiC atomic steps. In our analysis, we focus on large-scale, statistical properties to foster the scalable technology of industrial graphene for electronics and sensor applications.

  3. Analysis of toroidal phasing of resonant magnetic perturbation effects on edge transport in the DIII-D tokamak

    SciTech Connect (OSTI)

    Wilks, T. M.; Stacey, W. M.; Evans, T. E.

    2013-05-15

    Resonant Magnetic Perturbation (RMP) fields produced by external control coils are considered a viable option for the suppression of Edge Localized Modes in present and future tokamaks. In DIII-D, the RMPs are generated by six pairs of I-coils, each spanning 60° in toroidal angle, with the currents flowing in opposite directions in adjacent pairs of I-coils. Reversal of the currents in all I-coils, which produces a 60° toroidal shift in the RMP field configuration, generates uniquely different edge pedestal profiles of the density, temperature, and rotation velocities, implying different effects on the related edge transport phenomena caused by the difference in toroidal phase of the I-coil currents. The diffusive and non-diffusive transport effects of this RMP toroidal phase reversal are analyzed by comparing the ion and electron heat diffusivities, angular momentum transport frequencies, ion diffusion coefficients, and the particle pinch velocities interpreted from the measured profiles for the two phases of the I-coil currents.

  4. Investigation of mechanisms for He-I emission radial profile broadening in a weakly ionized cylindrical helium plasma with recombining edge

    SciTech Connect (OSTI)

    Hollmann, E. M.; Brandt, C.; Hudson, B.; Nishijima, D.; Pigarov, A. Yu.; Kumar, D.

    2013-09-15

    Spatially resolved spectroscopic measurements of He-I line emission are used to study the causes of emission profile broadening radially across the cylinder of a weakly ionized helium plasma. The plasma consists of an ionizing core (r < 2 cm) surrounded by a recombining edge (r > 2 cm) plasma. The brightness profiles of low-n EUV He-I resonance lines are shown to be strongly radially broadened due to opacity. The brightness profiles of high-n visible lines are also found to be strongly radially broadened, but dominantly due to edge recombination. Visible low-n lines are less strongly radially broadened, apparently by a combination of both recombination and EUV opacity. The low-n visible He-I line ratio method with central opacity correction is found to calculate central electron density and temperature well, with poor agreement at the edge, as expected for recombining plasma. In the recombining edge, high-n Boltzmann analysis is found to accurately measure the cold (T{sub e} < 0.2 eV) edge temperature. Near the core, however, high-n Boltzmann analysis can be complicated by electron-impact excitation, giving incorrect (T{sub e}? 0.1 eV) apparent temperatures. Probe measurements were not able to capture the cold edge temperature accurately, probably due to large potential fluctuations, even when using fast triple probe measurements. Fast spectroscopic measurements show that this discrepancy is not explained by recombining plasma alternating with ionizing plasma in the edge region.

  5. Progress report for FACETS (Framework Application for Core-Edge Transport Simulations): C.S. SAP

    SciTech Connect (OSTI)

    Epperly, T W

    2008-10-01

    The mission of the Computer Science Scientific Application Partnership (C.S. SAP) at LLNL is to develop and apply leading-edge scientific component technology to FACETS software. Contributions from LLNL's fusion energy program staff towards the underlying physics modules are described in a separate report. FACETS uses component technology to combine selectively multiple physics and solver software modules written in different languages by different institutions together in an tightly-integrated, parallel computing framework for Tokamak reactor modeling. In the past fiscal year, the C.S. SAP has focused on two primary tasks: applying Babel to connect UEDGE into the FACETS framework through UEDGE's existing Python interface and developing a next generation componentization strategy for UEDGE which avoids the use of Python. The FACETS project uses Babel to solve its language interoperability challenges. Specific accomplishments for the year include: (1) Refined SIDL interfaces for UEDGE to meet satisfy the standard interfaces required by FACETS for all physics modules. This required consensus building between framework and UEDGE developers. (2) Wrote prototype C++ driver for UEDGE to demonstrate how UEDGE can be called from C++ using Babel. (3) Supported the FACETS project by adding new features to Babel such as release number tagging, porting to new machines, and adding new configuration options. Babel modifications were delivered to FACETS by testing and publishing development snapshots in the projects software repository. (4) Assisted Tech-X Corporation in testing and debugging of a high level build system for the complete FACETS tool chain--the complete list of third-party software libraries that FACETS depends on directly or indirectly (e.g., MPI, HDF5, PACT, etc.). (5) Designed and implemented a new approach to wrapping UEDGE as a FACETS component without requiring Python. To get simulation results as soon as possible, our initial connection from the FACETS

  6. Simulating Ru L3-Edge X-ray Absorption Spectroscopy with Time-Dependent Density Functional Theory: Model Complexes and Electron Localization in Mixed-Valence Metal Dimers

    SciTech Connect (OSTI)

    Kuiken, Benjamin E. Van; Valiev, Marat; Daifuku, Stephanie L.; Bannan, Caitlin; Strader, Matthew L.; Cho, Hana; Huse, Nils; Schoenlein, Robert W.; Govind, Niranjan; Khalil, Munira

    2013-04-26

    Ruthenium L3-edge X-ray absorption (XA) spectroscopy probes unoccupied 4d orbitals of the metal atom and is increasingly being used to investigate the local electronic structure in ground and excited electronic states of Ru complexes. The simultaneous development of computational tools for simulating Ru L3-edge spectra is crucial for interpreting the spectral features at a molecular level. This study demonstrates that time-dependent density functional theory (TDDFT) is a viable and predictive tool for simulating ruthenium L3-edge XA spectroscopy. We systematically investigate the effects of exchange correlation functional and implicit and explicit solvent interactions on a series of RuII and RuIII complexes in their ground and electronic excited states. The TDDFT simulations reproduce all of the experimentally observed features in Ru L3-edge XA spectra within the experimental resolution (0.4 eV). Our simulations identify ligand-specific charge transfer features in complicated Ru L3-edge spectra of [Ru(CN)6]4- and RuII polypyridyl complexes illustrating the advantage of using TDDFT in complex systems. We conclude that the B3LYP functional most accurately predicts the transition energies of charge transfer features in these systems. We use our TDDFT approach to simulate experimental Ru L3-edge XA spectra of transition metal mixed-valence dimers of the form [(NC)5MII-CN-RuIII(NH3)5] (where M = Fe or Ru) dissolved in water. Our study determines the spectral signatures of electron delocalization in Ru L3-edge XA spectra. We find that the inclusion of explicit solvent molecules is necessary for reproducing the spectral features and the experimentally determined valencies in these mixed-valence complexes. This study validates the use of TDDFT for simulating Ru 2p excitations using popular quantum chemistry codes and providing a powerful interpretive tool for equilibrium and ultrafast Ru L3-edge XA spectroscopy.

  7. The quiescent H-mode regime for high performance edge localized mode-stable operation in future burning plasmas

    SciTech Connect (OSTI)

    Garofalo, A. M. Burrell, K. H.; Meneghini, O.; Osborne, T. H.; Paz-Soldan, C.; Smith, S. P.; Snyder, P. B.; Turnbull, A. D.; Eldon, D.; Grierson, B. A.; Solomon, W. M.; Hanson, J. M.; Holland, C.; Huijsmans, G. T. A.; Liu, F.; Loarte, A.; Zeng, L.

    2015-05-15

    For the first time, DIII-D experiments have achieved stationary quiescent H-mode (QH-mode) operation for many energy confinement times at simultaneous ITER-relevant values of beta, confinement, and safety factor, in an ITER-like shape. QH-mode provides excellent energy confinement, even at very low plasma rotation, while operating without edge localized modes (ELMs) and with strong impurity transport via the benign edge harmonic oscillation (EHO). By tailoring the plasma shape to improve the edge stability, the QH-mode operating space has also been extended to densities exceeding 80% of the Greenwald limit, overcoming the long-standing low-density limit of QH-mode operation. In the theory, the density range over which the plasma encounters the kink-peeling boundary widens as the plasma cross-section shaping is increased, thus increasing the QH-mode density threshold. The DIII-D results are in excellent agreement with these predictions, and nonlinear magnetohydrodynamic analysis of reconstructed QH-mode equilibria shows unstable low n kink-peeling modes growing to a saturated level, consistent with the theoretical picture of the EHO. Furthermore, high density operation in the QH-mode regime has opened a path to a new, previously predicted region of parameter space, named “Super H-mode” because it is characterized by very high pedestals that can be more than a factor of two above the peeling-ballooning stability limit for similar ELMing H-mode discharges at the same density.

  8. The use of bulk states to accelerate the band edge state calculation of a semiconductor quantum dot

    SciTech Connect (OSTI)

    Voemel, Christof . E-mail: voemel@eecs.berkeley.edu; Tomov, Stanimire Z. . E-mail: tomov@cs.utk.edu; Wang, Lin-Wang . E-mail: LWWang@lbl.gov; Marques, Osni A. . E-mail: OAMarques@lbl.gov; Dongarra, Jack J. . E-mail: dongarra@cs.utk.edu

    2007-05-01

    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.

  9. K-edge Subtraction Angiography with Synchrotron X-Rays: Final Technical Report, (February 1, 1984 to January 31, 1987)

    DOE R&D Accomplishments [OSTI]

    Hofstadter, R.

    1987-09-01

    The aim was the development of an angiographic method and appropriate equipment for imaging with x-rays the coronary arteries in a non-invasive manner. Successive steps involved studies with phantoms, live animals and finally with human subjects. Clinical evaluation of human coronary arteries remains a goal of this and a continuing project, and steps along the way to such an achievement are in process. Transvenous injection of a dye using the method of iodine dichromography near 33.2 keV, the K-edge of iodine, forms the basis of the method

  10. Resonant inelastic X-ray scattering spectrometer with 25meV resolution at the Cu K -edge

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ketenoglu, Didem; Harder, Manuel; Klementiev, Konstantin; Upton, Mary; Taherkhani, Mehran; Spiwek, Manfred; Dill, Frank-Uwe; Wille, Hans-Christian; Yavaş, Hasan

    2015-06-27

    An unparalleled resolution is reported with an inelastic X-ray scattering instrument at the CuK-edge. Based on a segmented concave analyzer, featuring single-crystal quartz (SiO2) pixels, the spectrometer delivers a resolution near 25meV (FWHM) at 8981eV. Besides the quartz analyzer, the performance of the spectrometer relies on a four-bounce Si(553) high-resolution monochromator and focusing Kirkpatrick–Baez optics. The measured resolution agrees with the ray-tracing simulation of an ideal spectrometer. The performance of the spectrometer is demonstrated by reproducing the phonon dispersion curve of a beryllium single-crystal.

  11. Enhanced Confinement Scenarios Without Large Edge Localized Modes in Tokamaks: Control, Performance, and Extrapolability Issues for ITER

    SciTech Connect (OSTI)

    Maingi, R

    2014-07-01

    Large edge localized modes (ELMs) typically accompany good H-mode confinement in fusion devices, but can present problems for plasma facing components because of high transient heat loads. Here the range of techniques for ELM control deployed in fusion devices is reviewed. The two baseline strategies in the ITER baseline design are emphasized: rapid ELM triggering and peak heat flux control via pellet injection, and the use of magnetic perturbations to suppress or mitigate ELMs. While both of these techniques are moderately well developed, with reasonable physical bases for projecting to ITER, differing observations between multiple devices are also discussed to highlight the needed community R & D. In addition, recent progress in ELM-free regimes, namely Quiescent H-mode, I-mode, and Enhanced Pedestal H-mode is reviewed, and open questions for extrapolability are discussed. Finally progress and outstanding issues in alternate ELM control techniques are reviewed: supersonic molecular beam injection, edge electron cyclotron heating, lower hybrid heating and/or current drive, controlled periodic jogs of the vertical centroid position, ELM pace-making via periodic magnetic perturbations, ELM elimination with lithium wall conditioning, and naturally occurring small ELM regimes.

  12. Impact of the pedestal plasma density on dynamics of edge localized mode crashes and energy loss scaling

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xu, X. Q.; Ma, J. F.; Li, G. Q.

    2014-12-29

    The latest BOUT++ studies show an emerging understanding of dynamics of edge localized mode(ELM) crashes and the consistent collisionality scaling of ELMenergy losses with the world multi-tokamak database. A series of BOUT++ simulations are conducted to investigate the scaling characteristics of the ELMenergy losses vs collisionality via a density scan. Moreover, the linear results demonstrate that as the pedestal collisionality decreases, the growth rate of the peeling-ballooning modes decreases for high n but increases for low n (1 < n < 5), therefore the width of the growth rate spectrum γ(n) becomes narrower and the peak growth shifts to lowermore » n. For nonlinear BOUT++ simulations show a two-stage process of ELM crash evolution of (i) initial bursts of pressure blob and void creation and (ii) inward void propagation. The inward void propagation stirs the top of pedestal plasma and yields an increasing ELM size with decreasing collisionality after a series of micro-bursts. The pedestal plasma density plays a major role in determining the ELMenergy loss through its effect on the edge bootstrap current and ion diamagnetic stabilization. Finally, the critical trend emerges as a transition (1) linearly from ballooning-dominated states at high collisionality to peeling-dominated states at low collisionality with decreasing density and (2) nonlinearly from turbulence spreading dynamics at high collisionality into avalanche-like dynamics at low collisionality.« less

  13. On the applicability of the standard approaches for evaluating a neoclassical radial electric field in a tokamak edge region

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dorf, M. A.; Cohen, R. H.; Simakov, A. N.; Joseph, I.

    2013-08-27

    The use of the standard approaches for evaluating a neoclassical radial electric field Er, i.e., the Ampere (or gyro-Poisson) equation, requires accurate calculation of the difference between the gyroaveraged electron and ion particle fluxes (or densities). In the core of a tokamak, the nontrivial difference appears only in high-order corrections to a local Maxwellian distribution due to the intrinsic ambipolarity of particle transport. The evaluation of such high-order corrections may be inconsistent with the accuracy of the standard long wavelength gyrokinetic equation (GKE), thus imposing limitations on the applicability of the standard approaches. However, in the edge of a tokamak,more » charge-exchange collisions with neutrals and prompt ion orbit losses can drive non-intrinsically ambipolar particle fluxes for which a nontrivial (Er-dependent) difference between the electron and ion fluxes appears already in a low order and can be accurately predicted by the long wavelength GKE. As a result, the parameter regimes where the radial electric field dynamics in the tokamak edge region is dominated by the non-intrinsically ambipolar processes, thus allowing for the use of the standard approaches, are discussed.« less

  14. Dependence of Recycling and Edge Profiles on Lithium Evaporation in High Triangularity, High Performance NSTX H-mode Discharges

    SciTech Connect (OSTI)

    Maingi, R; Osborne, T H; Bell, M G; Bell, R E; Boyle, D P; Canik, J M; Dialla, A; Kaita, R; Kaye, S M; Kugel, H W; LeBlanc, B P; Sabbagh, S A; Skinner, C H; Soukhanovskii, V A

    2014-04-01

    In this paper, the effects of a pre-discharge lithium evaporation scan on highly shaped discharges in the National Spherical Torus Experiment (NSTX) are documented. Lithium wall conditioning ('dose') was routinely applied onto graphite plasma facing components between discharges in NSTX, partly to reduce recycling. Reduced D[sub]α emission from the lower and upper divertor and center stack was observed, as well as reduced midplane neutral pressure; the magnitude of reduction increased with the pre-discharge lithium dose. Improved energy confinement, both raw τ[sub]E and H-factor normalized to scalings, with increasing lithium dose was also observed. At the highest doses, we also observed elimination of edge-localized modes. The midplane edge plasma profiles were dramatically altered, comparable to lithium dose scans at lower shaping, where the strike point was farther from the lithium deposition centroid. This indicates that the benefits of lithium conditioning should apply to the highly shaped plasmas planned in NSTX-U.

  15. Impact of the pedestal plasma density on dynamics of edge localized mode crashes and energy loss scaling

    SciTech Connect (OSTI)

    Xu, X. Q.; Ma, J. F.; Li, G. Q.

    2014-12-15

    The latest BOUT++ studies show an emerging understanding of dynamics of edge localized mode (ELM) crashes and the consistent collisionality scaling of ELM energy losses with the world multi-tokamak database. A series of BOUT++ simulations are conducted to investigate the scaling characteristics of the ELM energy losses vs collisionality via a density scan. Linear results demonstrate that as the pedestal collisionality decreases, the growth rate of the peeling-ballooning modes decreases for high n but increases for low n (1?edge bootstrap current and ion diamagnetic stabilization. The critical trend emerges as a transition (1) linearly from ballooning-dominated states at high collisionality to peeling-dominated states at low collisionality with decreasing density and (2) nonlinearly from turbulence spreading dynamics at high collisionality into avalanche-like dynamics at low collisionality.

  16. Near-coincident K-line and K-edge energies as ionization diagnostics for some high atomic number plasmas

    SciTech Connect (OSTI)

    Pereira, N. R.; Weber, B. V.; Phipps, D. G.; Schumer, J. W.; Seely, J. F.; Carroll, J. J.; Vanhoy, J. R.; Slabkowska, K.; Polasik, M.

    2012-10-15

    For some high atomic number atoms, the energy of the K-edge is tens of eVs higher than the K-line energy of another atom, so that a few eV increase in the line's energy results in a decreasing transmission of the x-ray through a filter of the matching material. The transmission of cold iridium's Asymptotically-Equal-To 63.287 keV K{alpha}{sub 2} line through a lutetium filter is 7% lower when emitted by ionized iridium, consistent with an energy increase of {Delta}{epsilon} Asymptotically-Equal-To 10{+-}1 eV associated with the ionization. Likewise, the transmission of the K{beta}{sub 1} line of ytterbium through a near-coincident K-edge filter changes depending on plasma parameters that should affect the ionization. Systematic exploration of filter-line pairs like these could become a unique tool for diagnostics of suitable high energy density plasmas.

  17. On the applicability of the standard approaches for evaluating a neoclassical radial electric field in a tokamak edge region

    SciTech Connect (OSTI)

    Dorf, M. A.; Cohen, R. H.; Joseph, I.; Simakov, A. N.

    2013-08-15

    The use of the standard approaches for evaluating a neoclassical radial electric field E{sub r}, i.e., the Ampere (or gyro-Poisson) equation, requires accurate calculation of the difference between the gyroaveraged electron and ion particle fluxes (or densities). In the core of a tokamak, the nontrivial difference appears only in high-order corrections to a local Maxwellian distribution due to the intrinsic ambipolarity of particle transport. The evaluation of such high-order corrections may be inconsistent with the accuracy of the standard long wavelength gyrokinetic equation (GKE), thus imposing limitations on the applicability of the standard approaches. However, in the edge of a tokamak, charge-exchange collisions with neutrals and prompt ion orbit losses can drive non-intrinsically ambipolar particle fluxes for which a nontrivial (E{sub r}-dependent) difference between the electron and ion fluxes appears already in a low order and can be accurately predicted by the long wavelength GKE. The parameter regimes, where the radial electric field dynamics in the tokamak edge region is dominated by the non-intrinsically ambipolar processes, thus allowing for the use of the standard approaches, are discussed.

  18. Local field effects at Li K edges in electron energy-loss spectra of Li, Li{sub 2}O and LiF

    SciTech Connect (OSTI)

    Mauchamp, V.; Moreau, P.; Ouvrard, G.; Boucher, F.

    2008-01-15

    Local field effects (LFEs) in low-losses of electron energy-loss spectra of Li, Li{sub 2}O, and LiF were calculated using the density functional theory under the generalized gradient approximation. By including the lithium 1s semicore state in the pseudopotentials, the amplitude of LFE was assessed all the way up to the Li K edge (from 0 to 80 eV). They are found to be much larger for semicore levels (2s of oxygen, 2s of fluorine, and 1s of lithium) than for the valence electron energy-loss region. LFEs at the Li K edge are studied in detail. In particular, for q=0 they are shown to increase with the inhomogeneities of the compounds (from Li to LiF). The influence of the magnitude and the direction of q is also presented. Both parameters have negligible effect in the case of Li metal but changes are quite substantial for Li{sub 2}O and LiF. This is in agreement with the isotropy and the delocalization of the metallic bonding as compared to the ionic one. LFEs at the Li K edge are, however, whatever the compound, much smaller than those observed at transition metal M{sub 2,3} edges situated at similar energy positions. This result can be accounted for by considering the wave functions associated with the initial and final states involved in both edges. For lithium battery materials, most often presenting a transition metal edge close to the Li K edge, these findings imply significant consequences with respect to the interpretation of their electron energy-loss spectroscopy spectra. In particular, LFE can be expected to be stronger in positive electrodes than in negative ones.

  19. Understanding the Electronic Structure of 4d Metal Complexes: From Molecular Spinors to L-Edge Spectra of a di-Ru Catalyst

    SciTech Connect (OSTI)

    Alperovich, Igor; Smolentsev, Grigory; Moonshiram, Dooshaye; Jurss, Jonah W.; Concepcion, Javier J.; Meyer, Thomas J.; Soldatov, Alexander; Pushkar, Yulia

    2015-09-17

    L{sub 2,3}-edge X-ray absorption spectroscopy (XAS) has demonstrated unique capabilities for the analysis of the electronic structure of di-Ru complexes such as the blue dimer cis,cis-[Ru{sub 2}{sup III}O(H{sub 2}O){sub 2}(bpy){sub 4}]{sup 4+} water oxidation catalyst. Spectra of the blue dimer and the monomeric [Ru(NH{sub 3}){sub 6}]{sup 3+} model complex show considerably different splitting of the Ru L{sub 2,3} absorption edge, which reflects changes in the relative energies of the Ru 4d orbitals caused by hybridization with a bridging ligand and spin-orbit coupling effects. To aid the interpretation of spectroscopic data, we developed a new approach, which computes L{sub 2,3}-edges XAS spectra as dipole transitions between molecular spinors of 4d transition metal complexes. This allows for careful inclusion of the spin-orbit coupling effects and the hybridization of the Ru 4d and ligand orbitals. The obtained theoretical Ru L{sub 2,3}-edge spectra are in close agreement with experiment. Critically, existing single-electron methods (FEFF, FDMNES) broadly used to simulate XAS could not reproduce the experimental Ru L-edge spectra for the [Ru(NH{sub 3}){sub 6}]{sup 3+} model complex nor for the blue dimer, while charge transfer multiplet (CTM) calculations were not applicable due to the complexity and low symmetry of the blue dimer water oxidation catalyst. We demonstrated that L-edge spectroscopy is informative for analysis of bridging metal complexes. The developed computational approach enhances L-edge spectroscopy as a tool for analysis of the electronic structures of complexes, materials, catalysts, and reactive intermediates with 4d transition metals.

  20. Application of Cutting-Edge 3D Seismic Attribute Technology to the Assessment of Geological Reservoirs for CO2 Sequestration

    SciTech Connect (OSTI)

    Christopher Liner; Jianjun Zeng; Po Geng Heather King Jintan Li; Jennifer Califf; John Seales

    2010-03-31

    The goals of this project were to develop innovative 3D seismic attribute technologies and workflows to assess the structural integrity and heterogeneity of subsurface reservoirs with potential for CO{sub 2} sequestration. Our specific objectives were to apply advanced seismic attributes to aide in quantifying reservoir properies and lateral continuity of CO{sub 2} sequestration targets. Our study area is the Dickman field in Ness County, Kansas, a type locality for the geology that will be encountered for CO{sub 2} sequestration projects from northern Oklahoma across the U.S. midcontent to Indiana and beyond. Since its discovery in 1962, the Dickman Field has produced about 1.7 million barrels of oil from porous Mississippian carbonates with a small structural closure at about 4400 ft drilling depth. Project data includes 3.3 square miles of 3D seismic data, 142 wells, with log, some core, and oil/water production data available. Only two wells penetrate the deep saline aquifer. Geological and seismic data were integrated to create a geological property model and a flow simulation grid. We systematically tested over a dozen seismic attributes, finding that curvature, SPICE, and ANT were particularly useful for mapping discontinuities in the data that likely indicated fracture trends. Our simulation results in the deep saline aquifer indicate two effective ways of reducing free CO{sub 2}: (a) injecting CO{sub 2} with brine water, and (b) horizontal well injection. A tuned combination of these methods can reduce the amount of free CO{sub 2} in the aquifer from over 50% to less than 10%.

  1. Flow augmenters for vertical-axis windmills and turbines

    SciTech Connect (OSTI)

    Evans, F.C.

    1981-03-10

    A windmill is disclosed, the windmill including a vertical shaft mounted for rotation about its longitudinal axis, a number of blades spaced circumferentially around the longitudinal axis, and being disposed generally parallel to the axis of rotation of the vertical shaft, and supporting arms extending radially outwardly from the vertical shaft for supporting the blades. The windmill also includes a first member connected to an upper end of one of the blades and defining a first surface having a leading edge with respect to the direction of movement of the blade and a trailing edge rearward of the leading edge, the leading edge being lower than the trailing edge. The first surface also includes an inside lateral edge and an outer lateral edge spaced radially outwardly from the inside lateral edge, the inside lateral edge being higher than the outer lateral edge. A second member is connected to the lower end of the blade and defines a second surface, the second surface having a leading edge with respect to the direction of movement of the blade and a trailing surface rearward of the second surface leading edge, the second surface leading edge being higher than the trailing edge. The second surface also includes an inside lateral edge and an outer lateral edge spaced radially outwardly from the second surface inside lateral edge, the second surface inside lateral edge being lower than the second surface outside lateral edge.

  2. Rotor blades for turbine engines

    DOE Patents [OSTI]

    Piersall, Matthew R; Potter, Brian D

    2013-02-12

    A tip shroud that includes a plurality of damping fins, each damping fin including a substantially non-radially-aligned surface that is configured to make contact with a tip shroud of a neighboring rotor blade. At least one damping fin may include a leading edge damping fin and at least one damping fin may include a trailing edge damping fin. The leading edge damping fin may be configured to correspond to the trailing edge damping fin.

  3. Low transient thermal stress turbine engine components

    DOE Patents [OSTI]

    Shi, Jun; Schmidt, Wayde R.

    2011-06-28

    A turbine vane includes a platform; and at least one airfoil mounted to the platform and having a trailing edge and a leading edge, wherein the vane is composed of a functionally graded material having a first material and a second material, wherein the trailing edge includes a greater amount of the first material than the second material, and the leading edge includes a greater amount of the second material than the first material.

  4. Visualization of the operational space of edge-localized modes through low-dimensional embedding of probability distributions

    SciTech Connect (OSTI)

    Shabbir, A. Noterdaeme, J. M.; Verdoolaege, G.; Kardaun, O. J. W. F.; Collaboration: JET-EFDA Team

    2014-11-15

    Information visualization aimed at facilitating human perception is an important tool for the interpretation of experiments on the basis of complex multidimensional data characterizing the operational space of fusion devices. This work describes a method for visualizing the operational space on a two-dimensional map and applies it to the discrimination of type I and type III edge-localized modes (ELMs) from a series of carbon-wall ELMy discharges at JET. The approach accounts for stochastic uncertainties that play an important role in fusion data sets, by modeling measurements with probability distributions in a metric space. The method is aimed at contributing to physical understanding of ELMs as well as their control. Furthermore, it is a general method that can be applied to the modeling of various other plasma phenomena as well.

  5. Simulations of gas puff effects on edge density and ICRF coupling in ASDEX upgrade using EMC3-Eirene

    SciTech Connect (OSTI)

    Zhang, W.; Lunt, T.; Bobkov, V.; Coster, D.; Brida, D.; Noterdaeme, J.-M.; Jacquet, P.; Feng, Y.

    2015-12-10

    Simulations were carried out with the 3D plasma transport code EMC3-EIRENE, to study the deuterium gas (D{sub 2}) puff effects on edge density and the coupling of Ion Cyclotron Range of Frequency (ICRF) power in ASDEX Upgrade. Firstly we simulated an inter-ELM phase of an H-mode discharge with a moderate (1.2 × 10{sup 22} electrons/s) lower divertor gas puff. Then we changed the gas source positions to the mid-plane or top of machine while keeping other conditions the same. Cases with different mid-plane or top gas valves are investigated. Our simulations indicate that compared to lower divertor gas puffing, the mid-plane gas puff can enhance the local density in front of the antennas most effectively, while a rather global (toroidally uniform) but significantly smaller enhancement is found for top gas puffing. Our results show quantitative agreement with the experiments.

  6. A high intensity solar cell invention: The edge-illuminated vertical multi-junction (VNJ) solar cell

    SciTech Connect (OSTI)

    Sater, B.L.

    1992-08-07

    This report contains a summary of a High Intensity Solar Cell (HI Cell) development carried out under the NIST/DOE Energy-Related Invention Program. The HI Cell, or Edge-Illuminated vertical Multi-junction Solar Cell, eliminates most major problems encountered with other concentrator solar cell designs. Its high voltage and low series resistance features make it ideally suited for efficient operation at high intensities. Computer modeling shows efficiencies near 30% at 500 suns intensity are possible with state-of-art processing. Development of a working model was largely successful before encountering an unexpected problem during the last fabrication step with the anti-reflection coating. Unfortunately, funding was exhausted before its resolution. Recommendations are made to resolve the AR coating problem and to integrate all the knowledge gained during this development into a viable prototype model. The invention will provide the technical and economic performance needed to make photovoltaic systems cost-effective for wide use.

  7. A high intensity solar cell invention: The edge-illuminated vertical multi-junction (VNJ) solar cell. Final report

    SciTech Connect (OSTI)

    Sater, B.L.

    1992-08-07

    This report contains a summary of a High Intensity Solar Cell (HI Cell) development carried out under the NIST/DOE Energy-Related Invention Program. The HI Cell, or Edge-Illuminated vertical Multi-junction Solar Cell, eliminates most major problems encountered with other concentrator solar cell designs. Its high voltage and low series resistance features make it ideally suited for efficient operation at high intensities. Computer modeling shows efficiencies near 30% at 500 suns intensity are possible with state-of-art processing. Development of a working model was largely successful before encountering an unexpected problem during the last fabrication step with the anti-reflection coating. Unfortunately, funding was exhausted before its resolution. Recommendations are made to resolve the AR coating problem and to integrate all the knowledge gained during this development into a viable prototype model. The invention will provide the technical and economic performance needed to make photovoltaic systems cost-effective for wide use.

  8. Experimental station for laser-based picosecond time-resolved x-ray absorption near-edge spectroscopy

    SciTech Connect (OSTI)

    Dorchies, F. Fedorov, N.; Lecherbourg, L.

    2015-07-15

    We present an experimental station designed for time-resolved X-ray Absorption Near-Edge Spectroscopy (XANES). It is based on ultrashort laser-plasma x-ray pulses generated from a table-top 100 mJ-class laser at 10 Hz repetition rate. A high transmission (10%–20%) x-ray beam line transport using polycapillary optics allows us to set the sample in an independent vacuum chamber, providing high flexibility over a wide spectral range from 0.5 up to 4 keV. Some XANES spectra are presented, demonstrating 1% noise level in only ∼1 mn and ∼100 cumulated laser shots. Time-resolved measurements are reported, indicating that the time resolution of the entire experimental station is 3.3 ± 0.6 ps rms.

  9. 3D Imaging of Nickel Oxidation States using Full Field X-ray Absorption Near Edge Structure Nanotomography

    SciTech Connect (OSTI)

    Nelson, George; Harris, William; Izzo, John; Grew, Kyle N.

    2012-01-20

    Reduction-oxidation (redox) cycling of the nickel electrocatalyst phase in the solid oxide fuel cell (SOFC) anode can lead to performance degradation and cell failure. A greater understanding of nickel redox mechanisms at the microstructural level is vital to future SOFC development. Transmission x-ray microscopy (TXM) provides several key techniques for exploring oxidation states within SOFC electrode microstructure. Specifically, x-ray nanotomography and x-ray absorption near edge structure (XANES) spectroscopy have been applied to study samples of varying nickel (Ni) and nickel oxide (NiO) compositions. The imaged samples are treated as mock SOFC anodes containing distinct regions of the materials in question. XANES spectra presented for the individual materials provide a basis for the further processing and analysis of mixed samples. Images of composite samples obtained are segmented, and the distinct nickel and nickel oxide phases are uniquely identified using full field XANES spectroscopy. Applications to SOFC analysis are discussed.

  10. On the importance of nuclear quantum motions in near edge x-ray absorption fine structure (NEXAFS) spectroscopy of molecules

    SciTech Connect (OSTI)

    Schwartz, Craig P.; Uejio, Janel S.; Saykally, Richard J.; Prendergast, David

    2009-02-26

    We report the effects of sampling nuclear quantum motion with path integral molecular dynamics (PIMD) on calculations of the nitrogen K-edge spectra of two isolated organic molecules. S-triazine, a prototypical aromatic molecule occupying primarily its vibrational ground state at room temperature, exhibits substantially improved spectral agreement when nuclear quantum effects are included via PIMD, as compared to the spectra obtained from either a single fixed-nuclei based calculation or from a series of configurations extracted from a classical molecular dynamics trajectory. Nuclear quantum dynamics can accurately explain the intrinsic broadening of certain features. Glycine, the simplest amino acid, is problematic due to large spectral variations associated with multiple energetically accessible conformations at the experimental temperature. This work highlights the sensitivity of NEXAFS to quantum nuclear motions in molecules, and the necessity of accurately sampling such quantum motion when simulating their NEXAFS spectra.

  11. Effect of the plasma shapes on intrinsic rotation due to collisionless ion orbit loss in the tokamak edge plasmas

    SciTech Connect (OSTI)

    Ou, Jing; Wu, Guojiang; Li, Xinxia

    2014-07-15

    Distribution of the intrinsic rotation due to collisionless ion orbit loss near the tokamak edge region is studied by using an analytical model based on ion guiding center orbit approximation. A peak of the averaged ion orbit loss momentum fraction is found very near inside the separatrix region in a double null divertor configuration but is not found inside the last closed flux surface region in an outer limiter configuration. For the double null divertor configuration, the intrinsic rotation due to ion orbit loss depends on the plasma shape. With the increase in elongation and triangularity, the peak of the averaged ion orbit loss momentum fraction increases and it moves inward for the lower plasma current.

  12. PySpline: A Modern, Cross-Platform Program for the Processing of Raw Averaged XAS Edge and EXAFS Data

    SciTech Connect (OSTI)

    Tenderholt, A.; Hedman, B.; Hodgson, K.O.

    2007-01-08

    PySpline is a modern computer program for processing raw averaged XAS and EXAFS data using an intuitive approach which allows the user to see the immediate effect of various processing parameters on the resulting k- and R-space data. The Python scripting language and Qt and Qwt widget libraries were chosen to meet the design requirement that it be cross-platform (i.e. versions for Windows, Mac OS X, and Linux). PySpline supports polynomial pre- and post-edge background subtraction, splining of the EXAFS region with a multi-segment polynomial spline, and Fast Fourier Transform (FFT) of the resulting k{sup 3}-weighted EXAFS data.

  13. Edge radial electric field structure and its connections to H-mode confinement in Alcator C-Mod plasmas

    SciTech Connect (OSTI)

    McDermott, R. M.; Lipschultz, B.; Hughes, J. W.; Catto, P. J.; Hubbard, A. E.; Hutchinson, I. H.; Granetz, R. S.; Greenwald, M.; LaBombard, B.; Marr, K.; Reinke, M. L.; Rice, J. E.; Whyte, D.

    2009-05-15

    High-resolution charge-exchange recombination spectroscopic measurements of B{sup 5+} ions have enabled the first spatially resolved calculations of the radial electric field (E{sub r}) in the Alcator C-Mod pedestal region [E. S. Marmar, Fusion Sci. Technol. 51, 261 (2006)]. These observations offer new challenges for theory and simulation and provide for important comparisons with other devices. Qualitatively, the field structure observed on C-Mod is similar to that on other tokamaks. However, the narrow high-confinement mode (H-mode) E{sub r} well widths (5 mm) observed on C-Mod suggest a scaling with machine size, while the observed depths (up to 300 kV/m) are unprecedented. Due to the strong ion-electron thermal coupling in the C-Mod pedestal, it is possible to infer information about the main ion population in this region. The results indicate that in H-mode the main ion pressure gradient is the dominant contributor to the E{sub r} well and that the main ions have significant edge flow. C-Mod H-mode data show a clear correlation between deeper E{sub r} wells, higher confinement plasmas, and higher electron temperature pedestal heights. However, improved L-mode (I-mode) plasmas exhibit energy confinement equivalent to that observed in similar H-mode discharges, but with significantly shallower E{sub r} wells. I-mode plasmas are characterized by H-mode-like energy barriers, but with L-mode-like particle barriers. The decoupling of energy and particle barrier formation makes the I-mode an interesting regime for fusion research and provides for a low collisionality pedestal without edge localized modes.

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

    SciTech Connect (OSTI)

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

    2015-12-07

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

  15. On the trail of the Higgs boson

    SciTech Connect (OSTI)

    Peskin, Michael E.

    2015-09-11

    I review theoretical issues associated with the Higgs boson and the mystery of spontaneous breaking of the electroweak gauge symmetry. In addition, this essay is intended as an introduction to the special issue of Annalen der Physik, Particle Physics after the Higgs.

  16. Trail Canyon Geothermal Project | Open Energy Information

    Open Energy Info (EERE)

    EFAULT","autoinfowindows":false,"kml":,"gkml":,"fusiontables":,"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":,"markercluster":false,"searchmarkers...

  17. On the trail of the Higgs boson

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Peskin, Michael E.

    2015-09-11

    I review theoretical issues associated with the Higgs boson and the mystery of spontaneous breaking of the electroweak gauge symmetry. In addition, this essay is intended as an introduction to the special issue of Annalen der Physik, “Particle Physics after the Higgs”.

  18. Houston's measured steps along the comeback trail

    SciTech Connect (OSTI)

    Gold, P.

    1990-06-18

    The Houston recession of the 1980s, a half dozen years of falling oil, rising bankruptcies and daily foreclosures, still shows in the faces and the demeanor of those who survived it. Today, however, the city is well along the path to recovery. Houston's unemployment rate has stabilized below 5 percent, better than Texas or the nation. More than 4,300 new jobs were created last year alone. From steel manufacturing to petrochemicals and the local hero corporation, Compaq Computer Corp., prospects are looking up. The long-depressed real estate market is attracting investors from Europe, Japan and New York. Venture capital and new business are coming in.

  19. SRNL is Hot on the [Fungi] Trail

    Broader source: Energy.gov [DOE]

    A team of microbiologists at SRNL are hard at work with Tuskegee University and Mississippi State University to decrease mold growth in flooded homes through improved prevention and cleanup.

  20. Reliability of AlGaN/GaN high electron mobility transistors on low dislocation density bulk GaN substrate: Implications of surface step edges

    SciTech Connect (OSTI)

    Killat, N. E-mail: Martin.Kuball@bristol.ac.uk; Montes Bajo, M.; Kuball, M. E-mail: Martin.Kuball@bristol.ac.uk; Paskova, T.; Materials Science and Engineering Department, North Carolina State University, Raleigh, North Carolina 27695 ; Evans, K. R.; Leach, J.; Electrical and Computer Engineering Department, Virginia Commonwealth University, Richmond, Virginia 23284 ; Li, X.; Özgür, Ü.; Morkoç, H.; Chabak, K. D.; Crespo, A.; Gillespie, J. K.; Fitch, R.; Kossler, M.; Walker, D. E.; Trejo, M.; Via, G. D.; Blevins, J. D.

    2013-11-04

    To enable gaining insight into degradation mechanisms of AlGaN/GaN high electron mobility transistors, devices grown on a low-dislocation-density bulk-GaN substrate were studied. Gate leakage current and electroluminescence (EL) monitoring revealed a progressive appearance of EL spots during off-state stress which signify the generation of gate current leakage paths. Atomic force microscopy evidenced the formation of semiconductor surface pits at the failure location, which corresponds to the interaction region of the gate contact edge and the edges of surface steps.

  1. Airfoil lance apparatus for homogeneous humidification and sorbent dispersion in a gas stream

    DOE Patents [OSTI]

    Myers, Robert B.; Yagiela, Anthony S.

    1990-12-25

    An apparatus for spraying an atomized mixture into a gas stream comprises a stream line airfoil member having a large radius leading edge and a small radius trailing edge. A nozzle assembly pierces the trailing edge of the airfoil member and is concentrically surrounded by a nacelle which directs shielding gas from the interior of the airfoil member around the nozzle assembly. Flowable medium to be atomized and atomizing gas for atomizing the medium are supplied in concentric conduits to the nozzle. A plurality of nozzles each surrounded by a nacelle are spaced along the trailing edge of the airfoil member.

  2. Airfoil lance apparatus for homogeneous humidification and sorbent dispersion in a gas stream

    DOE Patents [OSTI]

    Myers, R.B.; Yagiela, A.S.

    1990-12-25

    An apparatus for spraying an atomized mixture into a gas stream comprises a stream line airfoil member having a large radius leading edge and a small radius trailing edge. A nozzle assembly pierces the trailing edge of the airfoil member and is concentrically surrounded by a nacelle which directs shielding gas from the interior of the airfoil member around the nozzle assembly. Flowable medium to be atomized and atomizing gas for atomizing the medium are supplied in concentric conduits to the nozzle. A plurality of nozzles each surrounded by a nacelle are spaced along the trailing edge of the airfoil member. 3 figs.

  3. Vibrationally resolved NEXAFS at C and N K-edges of pyridine, 2-fluoropyridine and 2,6-difluoropyridine: A combined experimental and theoretical assessment

    SciTech Connect (OSTI)

    Baiardi, Alberto; Mendolicchio, Marco; Barone, Vincenzo; Fronzoni, Giovanna; Cardenas Jimenez, Gustavo Adolfo; Stener, Mauro; Grazioli, Cesare; Simone, Monica de; Coreno, Marcello

    2015-11-28

    In the present work, the near edge X-ray absorption spectroscopy (NEXAFS) spectra at both C and N K-edges of pyridine, 2-fluoropyridine, and 2,6-difluoropyridine have been studied both experimentally and theoretically. From an electronic point of view, both transition potential density functional theory and time-dependent density functional theory approaches lead to reliable results provided that suitable basis sets and density functionals are employed. In this connection, the global hybrid B3LYP functional in conjunction with the EPR-III basis set appears particularly suitable after constant scaling of the band positions. For the N K-edge, vertical energies obtained at these levels and broadened by symmetric Gaussian distributions provide spectra in reasonable agreement with the experiment. Vibronic contributions further modulate the band-shapes leading to a better agreement with the experimental results, but are not strictly necessary for semi-quantitative investigations. On the other hand, vibronic contributions are responsible for strong intensity redistribution in the NEXAFS C K-edge spectra, and their inclusion is thus mandatory for a proper description of experiments. In this connection, the simple vertical gradient model is particularly appealing in view of its sufficient reliability and low computational cost. For more quantitative results, the more refined vertical Hessian approach can be employed, and its effectiveness has been improved thanks to a new least-squares fitting approach.

  4. SU-C-207-06: In Vivo Quantification of Gold Nanoparticles Using K-Edge Imaging Via Spectrum Shaping by Gold Filter

    SciTech Connect (OSTI)

    Chen, H; Cormack, R; Bhagwat, M; Berbeco, R

    2015-06-15

    Purpose: Gold nanoparticles (AuNP) are multifunctional platforms ideal for drug delivery, targeted imaging and radiosensitization. We have investigated quantitative imaging of AuNPs using on board imager (OBI) cone beam computed tomography (CBCT). To this end, we also present, for the first time, a novel method for k-edge imaging of AuNP by filter-based spectral shaping. Methods: We used a digital 25 cm diameter water phantom, embedded with 3 cm spheres filled with AuNPs of different concentrations (0 mg/ml – 16 mg/ml). A poly-energetic X-ray spectrum of 140 kVp from a conventional X-ray tube is shaped by balanced K-edge filters to create an excess of photons right above the K-edge of gold at 80.7 keV. The filters consist of gold, tin, copper and aluminum foils. The phantom with appropriately assigned attenuation coefficients is forward projected onto a detector for each energy bin and then integrated. FKD reconstruction is performed on the integrated projections. Scatter, detector efficiency and noise are included. Results: We found that subtracting the results of two filter sets (Filter A:127 µm gold foil with 254 µm tin, 330 µm copper and 1 mm aluminum, and Filter B: 635 µm tin with 264 µm copper and 1 mm aluminum), provides substantial image contrast. The resulting filtered spectra match well below 80.7 keV, while maintaining sufficient X-ray quanta just above that. Voxel intensities of AuNP containing spheres increase linearly with AuNP concentration. K-edge imaging provides 18% more sensitivity than the tin filter alone, and 38% more sensitivity than the gold filter alone. Conclusion: We have shown that it is feasible to quantitatively detect AuNP distributions in a patient-sized phantom using clinical CBCT and K-edge spectral shaping.

  5. High frequency pacing of edge localized modes by injection of lithium granules in DIII-D H-mode discharges

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bortolon, A.; Maingi, R.; Mansfield, D. K.; Nagy, A.; Roquemore, A. L.; Baylor, L. R.; Commaux, N.; Jackson, G. L.; Gilson, E. P.; Lunsford, R.; et al

    2016-04-08

    A newly installed Lithium Granule Injector (LGI) was used to pace edge localized modes (ELM) in DIII-D. ELM pacing efficiency was studied injecting lithium granules of nominal diameter 0.3–0.9mm, speed of 50–120 m s-1 and average injection rates up to 100 Hz for 0.9mm granules and up to 700 Hz for 0.3mm granules. The efficiency of ELM triggering was found to depend strongly on size of the injected granules, with triggering efficiency close to 100% obtained with 0.9mm diameter granules, lower with smaller sizes, and weakly depending on granule velocity. Robust ELM pacing was demonstrated in ITER-like plasmas for themore » entire shot length, at ELM frequencies 3–5 times larger than the ‘natural’ ELM frequency observed in reference discharges. Within the range of ELM frequencies obtained, the peak ELM heat flux at the outer strike point was reduced with increasing pacing frequency. The peak heat flux reduction at the inner strike point appears to saturate at high pacing frequency. Lithium was found in the plasma core, with a concurrent reduction of metallic impurities and carbon. Altogether, high frequency ELM pacing using the lithium granule injection appears to be compatible with both H-mode energy confinement and attractive H-mode pedestal characteristics, but further assessment is need« less

  6. The interstellar medium and star formation in edge-on galaxies. II. NGC 4157, 4565, and 5907

    SciTech Connect (OSTI)

    Yim, Kijeong; Wong, Tony; Xue, Rui; Rand, Richard J.; Rosolowsky, Erik; Hulst, J. M. van der; Benjamin, Robert; Murphy, Eric J.

    2014-12-01

    We present a study of the vertical structure of the gaseous and stellar disks in a sample of edge-on galaxies (NGC 4157, 4565, and 5907) using BIMA/CARMA {sup 12}COJ=1→0, VLA Hi, and Spitzer 3.6 μm data. In order to take into account projection effects when we measure the disk thickness as a function of radius, we first obtain the inclination by modeling the radio data. Using the measurement of the disk thicknesses and the derived radial profiles of gas and stars, we estimate the corresponding volume densities and vertical velocity dispersions. Both stellar and gas disks have smoothly varying scale heights and velocity dispersions, contrary to assumptions of previous studies. Using the velocity dispersions, we find that the gravitational instability parameter Q follows a fairly uniform profile with radius and is ⩾1 across the star-forming disk. The star formation law has a slope that is significantly different from those found in more face-on galaxy studies, both in deprojected and pixel-by-pixel plots. Midplane gas pressure based on the varying scale heights and velocity dispersions appears to roughly hold a power-law correlation with the midplane volume density ratio.

  7. Determining Orientational Structure of Diamondoid Thiols Attached to Silver Using Near Edge X-ray Absorption Fine Structure Spectroscopy

    SciTech Connect (OSTI)

    Willey, T M; Lee, J I; Fabbri, J D; Wang, D; Nielsen, M; Randel, J C; Schreiner, P R; Fokin, A A; Tkachenko, B A; Fokina, N A; Dahl, J P; Carlson, R K; Terminello, L J; Melosh, N A; van Buuren, T

    2008-10-07

    Near-edge x-ray absorption fine structure spectroscopy (NEXAFS) is a powerful tool for determination of molecular orientation in self-assembled monolayers and other surface-attached molecules. A general framework for using NEXAFS to simultaneously determine molecular tilt and twist of rigid molecules attached to surfaces is presented. This framework is applied to self-assembled monolayers of higher diamondoid, hydrocarbon molecules with cubic-diamond-cage structures. Diamondoid monolayers chemisorbed on metal substrates are known to exhibit interesting electronic and surface properties. This work compares molecular orientation in monolayers prepared on silver substrates using two different thiol positional isomers of [121]tetramantane, and thiols derived from two different pentamantane structural isomers, [1212]pentamantane and [1(2,3)4]pentamantane. The observed differences in monolayer structure demonstrate the utility and limitations of NEXAFS spectroscopy and the framework. The results also demonstrate the ability to control diamondoid assembly, in particular the molecular orientational structure, providing a flexible platform for the modification of surface properties with this exciting new class of nanodiamond materials.

  8. Getting to low-cost algal biofuels: A monograph on conventional and cutting-edge harvesting and extraction technologies

    SciTech Connect (OSTI)

    Coons, James E.; Kalb, Daniel M.; Dale, Taraka; Marrone, Babetta L.

    2014-08-31

    Among the most formidable challenges to algal biofuels is the ability to harvest algae and extract intracellular lipids at low cost and with a positive energy balance. Here, we construct two paradigms that contrast energy requirements and costs of conventional and cutting-edge Harvesting and Extraction (H&E) technologies. By application of the parity criterion and the moderate condition reference state, an energy–cost paradigm is created that allows 1st stage harvesting technologies to be compared with easy reference to the National Alliance for Advanced Biofuels and Bioproducts (NAABB) target of $0.013/gallon of gasoline equivalent (GGE) and to the U.S. DOE's Bioenergy Technologies Office 2022 cost metrics. Drawing from the moderate condition reference state, a concentration-dependency paradigm is developed for extraction technologies, making easier comparison to the National Algal Biofuels Technology Roadmap (NABTR) target of less than 10% total energy. This monograph identifies cost-bearing factors for a variety of H&E technologies, describes a design basis for ultrasonic harvesters, and provides a framework to measure future technological advancements toward reducing H&E costs. Finally, we show that ultrasonic harvesters and extractors are uniquely capable of meeting both NAABB and NABTR targets. Ultrasonic technologies require further development and scale-up before they can achieve low-cost performance at industrially relevant scales. But, the advancement of this technology would greatly reduce H&E costs and accelerate the commercial viability of algae-based biofuels.

  9. Depositional environments, sequence stratigraphy, and trap configuration of lower Wolfcampian clastics along eastern edge of Midland basin, west Texas

    SciTech Connect (OSTI)

    Stewart, N.R.; Reuter, S.G.

    1989-03-01

    The Lower Permian (lower Wolfcampian) along the eastern edge of the Midland basin, west Texas, is characterized by ramp-type shelf margins. During eustatic lowstand, nearshore sedimentation shifted drastically to the west into a basinal setting below the Pennsylvanian (Canyon) shelf margin. Core descriptions demonstrate that lowstand systems tract (LST) and transgressive systems tract (TST) siliciclastics were deposited in deltaic and coastal-plain environments. Prodelta, delta-front, and stream-mouth bar facies are associated with the LST. Coastal-plain and distributary channels are preserved in the TST. The sequence stratigraphic framework indicates type 1 sequence boundaries at 287 Ma, 282 Ma, and 280 Ma in the lower Wolfcampian clastics. This lower Wolfcampian package of sedimentary rocks overlies the Pennsylvanian and is capped by the 279-Ma middle Wolfcampian unconformity. All three sequence boundaries and associated systems tract deposits exhibit a prograding stacking pattern within the sequence stratigraphic framework. Basinally restricted prograding LST deltaic rocks are overlain by backstepping TST deltaics and highstand systems tract (HST) outer marine shales. Production in lower Wolfcampian clastic fields is associated with fine-grained quartzarenites up to 45 ft thick which were deposited in stream-mouth bars. Delta-front and prodelta low-permeability shales encase the reservoir facies, forming lateral permeability barriers. HST outer marine shales deposited over the stream-mouth-bar sandstones act as a top seal, creating a stratigraphic trap and providing source for the high-BTU gas and oil produced from these basinally restricted LST deltaics.

  10. New Whole-House Solutions Case Study: Exterior Rigid Foam Insulation at the Edge of a Slab Foundation, Fresno, California

    SciTech Connect (OSTI)

    2013-10-01

    Exterior rigid foam insulation at the edge of the slab foundation was a unique feature for this low-load, unoccupied test house in a hot-dry climate and may be more appropriate for climates with higher heating loads. U.S. Department of Energy Building America research team IBACOS worked with National Housing Quality Award winner Wathen-Castanos Hybrid Homes, Inc., to assess the performance of this feature in a single-family detached ranch house with three bedrooms and two full bathrooms constructed on a slab-on-grade foundation in Fresno, California. One challenge during installation of the system was the attachment of the butyl flashing to the open framing. To solve this constructability issue, the team added a nailer to the base of the wall to properly attach and lap the flashing. In this strategy, R-7.5, 1.5-in.-thick extruded polystyrene was installed on the exterior of the slab for a modeled savings of 4,500 Btu/h on the heating load.

  11. Near wall cooling for a highly tapered turbine blade

    DOE Patents [OSTI]

    Liang, George

    2011-03-08

    A turbine blade having a pressure sidewall and a suction sidewall connected at chordally spaced leading and trailing edges to define a cooling cavity. Pressure and suction side inner walls extend radially within the cooling cavity and define pressure and suction side near wall chambers. A plurality of mid-chord channels extend radially from a radially intermediate location on the blade to a tip passage at the blade tip for connecting the pressure side and suction side near wall chambers in fluid communication with the tip passage. In addition, radially extending leading edge and trailing edge flow channels are located adjacent to the leading and trailing edges, respectively, and cooling fluid flows in a triple-pass serpentine path as it flows through the leading edge flow channel, the near wall chambers and the trailing edge flow channel.

  12. Edge compression manifold apparatus

    SciTech Connect (OSTI)

    Renzi, Ronald F.

    2004-12-21

    A manifold for connecting external capillaries to the inlet and/or outlet ports of a microfluidic device for high pressure applications is provided. The fluid connector for coupling at least one fluid conduit to a corresponding port of a substrate that includes: (i) a manifold comprising one or more channels extending therethrough wherein each channel is at least partially threaded, (ii) one or more threaded ferrules each defining a bore extending therethrough with each ferrule supporting a fluid conduit wherein each ferrule is threaded into a channel of the manifold, (iii) a substrate having one or more ports on its upper surface wherein the substrate is positioned below the manifold so that the one or more ports is aligned with the one or more channels of the manifold, and (iv) device to apply an axial compressive force to the substrate to couple the one or more ports of the substrate to a corresponding proximal end of a fluid conduit.

  13. Edge compression manifold apparatus

    SciTech Connect (OSTI)

    Renzi, Ronald F.

    2007-02-27

    A manifold for connecting external capillaries to the inlet and/or outlet ports of a microfluidic device for high pressure applications is provided. The fluid connector for coupling at least one fluid conduit to a corresponding port of a substrate that includes: (i) a manifold comprising one or more channels extending therethrough wherein each channel is at least partially threaded, (ii) one or more threaded ferrules each defining a bore extending therethrough with each ferrule supporting a fluid conduit wherein each ferrule is threaded into a channel of the manifold, (iii) a substrate having one or more ports on its upper surface wherein the substrate is positioned below the manifold so that the one or more ports is aligned with the one or more channels of the manifold, and (iv) device to apply an axial compressive force to the substrate to couple the one or more ports of the substrate to a corresponding proximal end of a fluid conduit.

  14. Slab Edge Insulation

    SciTech Connect (OSTI)

    2009-05-14

    This information sheet addresses ways to mitigate heat loss and moisture management through slab on grade construction.

  15. Getting to low-cost algal biofuels: A monograph on conventional and cutting-edge harvesting and extraction technologies

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Coons, James E.; Kalb, Daniel M.; Dale, Taraka; Marrone, Babetta L.

    2014-08-31

    Among the most formidable challenges to algal biofuels is the ability to harvest algae and extract intracellular lipids at low cost and with a positive energy balance. Here, we construct two paradigms that contrast energy requirements and costs of conventional and cutting-edge Harvesting and Extraction (H&E) technologies. By application of the parity criterion and the moderate condition reference state, an energy–cost paradigm is created that allows 1st stage harvesting technologies to be compared with easy reference to the National Alliance for Advanced Biofuels and Bioproducts (NAABB) target of $0.013/gallon of gasoline equivalent (GGE) and to the U.S. DOE's Bioenergy Technologiesmore » Office 2022 cost metrics. Drawing from the moderate condition reference state, a concentration-dependency paradigm is developed for extraction technologies, making easier comparison to the National Algal Biofuels Technology Roadmap (NABTR) target of less than 10% total energy. This monograph identifies cost-bearing factors for a variety of H&E technologies, describes a design basis for ultrasonic harvesters, and provides a framework to measure future technological advancements toward reducing H&E costs. Finally, we show that ultrasonic harvesters and extractors are uniquely capable of meeting both NAABB and NABTR targets. Ultrasonic technologies require further development and scale-up before they can achieve low-cost performance at industrially relevant scales. But, the advancement of this technology would greatly reduce H&E costs and accelerate the commercial viability of algae-based biofuels.« less

  16. Turbine blades and systems with forward blowing slots

    SciTech Connect (OSTI)

    Zuteck, Michael D.; Zalusky, Leigh; Lees, Paul

    2015-09-15

    A blade for use in a wind turbine comprises a pressure side and suction side meeting at a trailing edge and leading edge. The pressure side and suction side provide lift to the turbine blade upon the flow of air from the leading edge to the trailing edge and over the pressure side and suction side. The blade includes one or more openings at the suction side, in some cases between the leading edge and the trailing edge. The one or more openings are configured to provide a pressurized fluid towards the leading edge of the blade, in some cases at an angle between about 0.degree. and 70.degree. with respect to an axis oriented from a centerline of the blade toward the leading edge.

  17. Effect of ion orbit loss on the structure in the H-mode tokamak edge pedestal profiles of rotation velocity, radial electric field, density, and temperature

    SciTech Connect (OSTI)

    Stacey, Weston M.

    2013-09-15

    An investigation of the effect of ion orbit loss of thermal ions and the compensating return ion current directly on the radial ion flux flowing in the plasma, and thereby indirectly on the toroidal and poloidal rotation velocity profiles, the radial electric field, density, and temperature profiles, and the interpretation of diffusive and non-diffusive transport coefficients in the plasma edge, is described. Illustrative calculations for a high-confinement H-mode DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] plasma are presented and compared with experimental results. Taking into account, ion orbit loss of thermal ions and the compensating return ion current is found to have a significant effect on the structure of the radial profiles of these quantities in the edge plasma, indicating the necessity of taking ion orbit loss effects into account in interpreting or predicting these quantities.

  18. X-ray magnetic circular dichroism at the U M{sub 4,5} absorption edges of UFe{sub 2}

    SciTech Connect (OSTI)

    Finazzi, M.; Sainctavit, P.; Dias, A.; Kappler, J.; Krill, G.; Sanchez, J.; Dalmas de Reotier, P.; Yaouanc, A.; Rogalev, A.; Goulon, J.

    1997-02-01

    We present an x-ray magnetic circular dichroism study performed at the U M{sub 4,5} edges on UFe{sub 2}, a ferromagnet with almost itinerant 5f electrons. The analysis of the branching ratio of the U M{sub 4,5} edges confirms the fact that the occupation number of the 5f states in UFe{sub 2} is lower than in other compounds where the f electrons are more localized. Magnetic circular dichroism effects are observed consistently with the presence of an orbital 5f magnetic moment which aligns parallel to the total magnetic moment. In agreement with a polarized neutron study, we find a nearly perfect cancellation of the U-5f spin and orbital magnetic moments, which results in a vanishing small total U-5f magnetic moment. Results are discussed in comparison with atomic multiplet calculations. {copyright} {ital 1997} {ital The American Physical Society}

  19. In Situ Observation of Water Dissociation with Lattice Incorporation at FeO Particle Edges Using Scanning Tunneling Microscopy and X-ray Photoelectron Spectroscopy

    SciTech Connect (OSTI)

    Deng, Xingyi; Lee, Junseok; Wang, Congjun; Matranga, Christopher; Aksoy, Funda; Liu, Zhi

    2011-03-15

    The dissociation of H2O and formation of adsorbed hydroxyl groups, on FeO particles grown on Au(111) were identified with in situ,: X:ray photoelectron spectroscopy (XPS) at water pressures ranging from 3 x 10-8 to 0.1 Torr. The facile dissociation of H2O takes place at FeO particle edges, and it was successfully observed in situ With atomically resolved scanning tunneling microscopy (STM). The in situ STM studies show that adsorbed hydroxyl groups were formed exclusively along the edges of the FeO particles with the 0 atom becoming directly incorporated into the oxide crystalline lattice The STM results are consistent with coordinatively unsaturated ferrous (CUF) sites along the FeO particle edge causing the observed reactivity with H2O. Our results also directly illustrate how structural defects and under.-coordinated sites participate in chemical reactions.

  20. Evidence of a Shockley-Read-Hall Defect State Independent of Band-Edge Energy in InAs/In(As,Sb) Type-II Superlattices

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aytac, Y.; Olson, B. V.; Kim, J. K.; Shaner, E. A.; Hawkins, S. D.; Klem, J. F.; Flatté, M. E.; Boggess, T. F.

    2016-05-24

    A set of seven InAs/InAsSb type-II superlattices (T2SLs) were designed to have speci c bandgap energies between 290 meV (4.3 m) and 135 meV (9.2 m) in order to study the e ects of the T2SL bandgap energy on the minority carrier lifetime. A temperature dependent optical pump-probe technique is used to measure the carrier lifetimes, and the e ect of a mid-gap defect level on the carrier recombination dynamics is reported. The Shockley-Read-Hall (SRH) defect state is found to be at energy of approximately -250 12 meV relative to the valence band edge of bulk GaSb for the entiremore » set of T2SL structures, even though the T2SL valence band edge shifts by 155 meV on the same scale. These results indicate that the SRH defect state in InAs/InAsSb T2SLs is singular and is nearly independent of the exact position of the T2SL bandgap or band edge energies. They also suggest the possibility of engineering the T2SL structure such that the SRH state is removed completely from the bandgap, a result that should signi cantly increase the minority carrier lifetime.« less

  1. Soft x-ray measurement of the toroidal pinch experiment RX reversed field pinch plasma using transition edge sensor calorimeter

    SciTech Connect (OSTI)

    Shinozaki, Keisuke; Hoshino, Akio; Ishisaki, Yoshitaka; Morita, Umeyo; Ohashi, Takaya; Mihara, Tatehiro; Mitsuda, Kazuhisa; Tanaka, Keiichi; Yagi, Yasuyuki; Koguchi, Haruhisa; Hirano, Yoichi; Sakakita, Hajime

    2006-04-15

    A superconductive transition edge sensor (TES) calorimeter is for the first time applied for the diagnostics of the reversed field pinch plasma produced in the toroidal pinch experiment RX (TPE-RX), and the instrumental system is fully described. The first result from the soft x-ray spectroscopy in 0.2-3 keV with an energy resolution {approx}50 eV are also presented. The TES calorimeter is made of a thin bilayer film of titanium and gold with a transition temperature of 151 mK and its best energy resolution at our laboratory is 6.4 eV, while it was significantly degraded by about a factor of eight during the plasma operation. The TES microcalorimeter was installed in a portable adiabatic demagnetization refrigerator (ADR), which is originally designed for a rocket experiment. The detector box is carefully designed to shield the strong magnetic field produced by the ADR and TPE-RX. The ADR was directly connected to TPE-RX with a vacuum duct in the sideway configuration, and cooled down to 125 mK stabilized with an accuracy of 10 {mu}K rms using an improved proportional, integral, and derivative (PID) control method. Thin aluminized Toray Lumirror or Parylene-N films were used for the IR to UV blocking filters of the incident x-ray window to allow soft x-rays coming into the detector with good efficiency. TPE-RX was operated with the plasma current of I{sub p}=220 kA, and the wave forms of the TES output for every plasma shot lasting {approx}80 ms were obtained with a digital oscilloscope. The wave forms were analyzed with the optimal filtering method, and x-ray signals were extracted. A total of 3472 counts of x-ray signals were detected for 210 plasma shots during the flat-top phase of t=35-70 ms. Combined with the data measured with a lithium drifted silicon detector in the 1.3-8 keV range, spectral features are investigated using a spectral fitting package XSPEC. The obtained spectrum is well explained by thermal plasma emission, although an impurity iron-L line

  2. An improved neutral diffusion model and numerical solution of the two dimensional edge plasma fluid equations. Final report

    SciTech Connect (OSTI)

    Prinja, A.K.

    1998-09-01

    relatively smooth as a consequence of the less localized recycling, leading to an improved convergence rate of the numerical algorithm. Peak plasma density is lower and the temperature correspondingly higher than those predicted by the standard diffusion model. It is believed that the FFCD model is more accurate. With both the TP continuation and multigrid methods, the author has demonstrated the robustness of these two methods. A mutually beneficial hybridization between the TP method and multigrid methods is clearly an alternative for edge plasma simulation. While the fundamental transport model considered in this work has ignored important physics such as drifts and currents, he has nevertheless demonstrated the versatility and robustness of the numerical scheme to handle such new physics. The application of gaseous-radiative divertor model in this work is just a beginning and up to this point numerically, the future is exciting.

  3. Scrape-off Layer Current Model for Filament Structure Observed during Edge Localized Modes (ELMs) in the DIII-D Tokamak

    SciTech Connect (OSTI)

    Takahashi, Hironori; Fredrickson, E. D.; Schaffer, M. J.

    2008-04-15

    The plasma in tokamaks often exhibits a relaxation oscillation called the edge localized mode (ELM), which is generally attributed to MHD instability driven by strong gradients at the plasma boundary. It is shown here that field-aligned currents flowing just outside the boundary may also play a role in the ELM process. The poloidal perturbation magnetic field during ELMs in the DIIID tokamak calculated from measured currents can reproduce prominent observed features, including a narrow magnetic structure at the outboard midplane similar to filaments observed earlier in DIIID and NSTX.

  4. Localization-delocalization transition of electrons at the percolation threshold of semiconductor GaAs1–xNx alloys: The appearance of a mobility edge

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Alberi, K.; Fluegel, B.; Beaton, D. A.; Ptak, A. J.; Mascarenhas, A.

    2012-07-09

    Electrons in semiconductor alloys have generally been described in terms of Bloch states that evolve from constructive interference of electron waves scattering from perfectly periodic potentials, despite the loss of structural periodicity that occurs on alloying. Using the semiconductor alloy GaAs₁₋xNx as a prototype, we demonstrate a localized to delocalized transition of the electronic states at a percolation threshold, the emergence of a mobility edge, and the onset of an abrupt perturbation to the host GaAs electronic structure, shedding light on the evolution of electronic structure in these abnormal alloys.

  5. Modulation of contact resistance between metal and graphene by controlling the graphene edge, contact area, and point defects: An ab initio study

    SciTech Connect (OSTI)

    Ma, Bo; Wen, Yanwei E-mail: bshan@mail.hust.edu.cn; Gong, Cheng; Cho, Kyeongjae; Chen, Rong; Shan, Bin E-mail: bshan@mail.hust.edu.cn

    2014-05-14

    A systematic first-principles non-equilibrium Green's function study is conducted on the contact resistance between a series of metals (Au, Ag, Pt, Cu, Ni, and Pd) and graphene in the side contact geometry. Different factors such as the termination of the graphene edge, contact area, and point defect in contacted graphene are investigated. Notable differences are observed in structural configurations and electronic transport characteristics of these metal-graphene contacts, depending on the metal species and aforementioned influencing factors. It is found that the enhanced chemical reactivity of the graphene due to dangling bonds from either the unsaturated graphene edge or point defects strengthens the metal-graphene bonding, leading to a considerable contact resistance reduction for weakly interacting metals Au and Ag. For stronger interacting metals Pt and Cu, a slightly reduced contact resistance is found due to such influencing factors. However, the wetting metals Ni and Pd most strongly hybridize with graphene, exhibiting negligible dependence on the above influencing factors. This study provides guidance for the optimization of metal-graphene contacts at an atomic scale.

  6. Resonance in fast-wave amplitude in the periphery of cylindrical plasmas and application to edge losses of wave heating power in tokamaks

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Perkins, R. J.; Hosea, J. C.; Bertelli, N.; Taylor, G.; Wilson, J. R.

    2016-07-01

    Heating magnetically confined plasmas using waves in the ion-cyclotron range of frequencies typically requires coupling these waves over a steep density gradient. Furthermore, this process has produced an unexpected and deleterious phenomenon on the National Spherical Torus eXperiment (NSTX): a prompt loss of wave power along magnetic field lines in front of the antenna to the divertor. Understanding this loss may be key to achieving effective heating and expanding the operational space of NSTX-Upgrade. Here, we propose that a new type of mode, which conducts a significant fraction of the total wave power in the low-density peripheral plasma, is drivingmore » these losses. We demonstrate the existence of such modes, which are distinct from surface modes and coaxial modes, in a cylindrical cold-plasma model when a half wavelength structure fits into the region outside the core plasma. The latter condition generalizes the previous hypothesis regarding the occurence of the edge losses and may explain why full-wave simulations predict these losses in some cases but not others. If valid, this condition implies that outer gap control is a potential strategy for mitigating the losses in NSTX-Upgrade in addition to raising the magnetic field or influencing the edge density.« less

  7. Evidence for a defect level above the conduction band edge of InAs/InAsSb type-II superlattices for applications in efficient infrared photodetectors

    SciTech Connect (OSTI)

    Prins, A. D.; Lewis, M. K.; Bushell, Z. L.; Sweeney, S. J.; Liu, S.; Zhang, Y.-H.

    2015-04-27

    We report pressure-dependent photoluminescence (PL) experiments under hydrostatic pressures up to 2.16?GPa on a mid-wave infrared InAs/InAs{sub 0.86}Sb{sub 0.14} type-II superlattice (T2SL) structure at different pump laser excitation powers and sample temperatures. The pressure coefficient of the T2SL transition was found to be 93??2?meVGPa{sup ?1}. The integrated PL intensity increases with pressure up to 1.9?GPa then quenches rapidly indicating a pressure induced level crossing with the conduction band states at ?2?GPa. Analysis of the PL intensity as a function of excitation power at 0, 0.42, 1.87, and 2.16?GPa shows a clear change in the dominant photo-generated carrier recombination mechanism from radiative to defect related. From these data, evidence for a defect level situated at 0.18??0.01?eV above the conduction band edge of InAs at ambient pressure is presented. This assumes a pressure-dependent energy shift of ?11?meVGPa{sup ?1} for the valence band edge and that the defect level is insensitive to pressure, both of which are supported by an Arrhenius activation energy analysis.

  8. Microsoft Word - SAND2012-10109.docx

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... a full turbine. The developed methodology was used to investigate the effects of a candidate blade damage feature, a trailing edge disbond, on a 5-MW offshore wind turbine and the ...

  9. Microsoft Word - AWEA-092867CA.docx

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Aerodynamic Load Control on the trailing edge of the blade tip for 1.5MW and 5MW wind turbines has been investigated. These results are based on time-series simulations performed...

  10. Near-edge X-ray Absorption Fine Structure Study of Disordering in Gd₂(Ti1-yZry)₂O₇ Pyrochlores

    SciTech Connect (OSTI)

    Nachimuthu, Ponnusamy; Thevuthasan, Suntharampillai; Adams, Evan M.; Weber, William J.; Begg, Bruce D.; Mun, B S.; Shuh, David K.; Lindle, Dennis W.; Gullikson, Eric M.; Perera, Rupert C.

    2005-02-03

    Disorder in Gd₂(Ti1-yZry)₂O₇ pyrochlores, for y=0.0-1.0, is investigated by Ti 2p and O 1s near-edge x-ray absorption fine structure spectroscopy. Ti⁴⁺ ions are found to occupy octahedral sites in Gd₂Ti₂O₇ with a tetragonal distortion induced by vacant oxygen sites. As Zr substitutes for Ti, the tetragonal distortion decreases, and Zr coordination increases from 6 to 8. The migration of oxygen ions from 48f or 8b sites to vacant 8a sites compensate for the increased Zr coordination, thereby reducing the number of vacant 8a sites, which further reduces the tetragonal distortion and introduces more disorder around Ti. This is evidence for simultaneous cation disorder with anion migration.

  11. 1.9 W continuous-wave single transverse mode emission from 1060?nm edge-emitting lasers with vertically extended lasing area

    SciTech Connect (OSTI)

    Miah, M. J. Posilovic, K.; Kalosha, V. P.; Rosales, R.; Bimberg, D.; Kettler, T.; Skoczowsky, D.; Pohl, J.; Weyers, M.

    2014-10-13

    High-brightness edge-emitting semiconductor lasers having a vertically extended waveguide structure emitting in the 1060?nm range are investigated. Ridge waveguide (RW) lasers with 9??m stripe width and 2.64?mm cavity length yield highest to date single transverse mode output power for RW lasers in the 1060?nm range. The lasers provide 1.9 W single transverse mode optical power under continuous-wave (cw) operation with narrow beam divergences of 9 in lateral and 14 (full width at half maximum) in vertical direction. The beam quality factor M{sup 2} is less than 1.9 up to 1.9 W optical power. A maximum brightness of 72 MWcm{sup ?2}sr{sup ?1} is obtained. 100??m wide and 3?mm long unpassivated broad area lasers provide more than 9 W optical power in cw operation.

  12. The distribution of ion orbit loss fluxes of ions and energy from the plasma edge across the last closed flux surface into the scrape-off layer

    SciTech Connect (OSTI)

    Stacey, Weston M.; Schumann, Matthew T.

    2015-04-15

    A more detailed calculation strategy for the evaluation of ion orbit loss of thermalized plasma ions in the edge of tokamaks is presented. In both this and previous papers, the direct loss of particles from internal flux surfaces is calculated from the conservation of canonical angular momentum, energy, and magnetic moment. The previous result that almost all of the ion energy and particle fluxes crossing the last closed flux surface are in the form of ion orbit fluxes is confirmed, and the new result that the distributions of these fluxes crossing the last closed flux surface into the scrape-off layer are very strongly peaked about the outboard midplane is demonstrated. Previous results of a preferential loss of counter current particles leading to a co-current intrinsic rotation peaking just inside of the last closed flux surface are confirmed. Various physical details are discussed.

  13. The Effects of Nitrogen on the Interface State Density Near the Conduction Band Edge in 4H and 6H-SiC

    SciTech Connect (OSTI)

    Chung, G.Y.; Tin, C.C.; Isaacs-Smith, T.; Williams, J.R.; McDonald, K.; DiVentra, M.; Pantelides, S.T.; Feldman, L.C.; Weller, R.A.; Holland, O.W.

    2000-06-12

    Results are reported for the passivation of interface states near the conduction band edge in SiO{sub 2}/SiC MOS capacitors using post-oxidation anneals in nitric oxide, ammonia and forming gas (N{sub 2}5%H{sub 2}). Anneals in nitric oxide and ammonia reduce the interface state density significantly for 4H-SiC, while forming gas anneals are largely ineffective. Results suggest that interface states in SiO{sub 2}/SiC and SiO{sub 2}/SiC have different origins, and a model is described for interface state passivation by nitrogen in the SiO{sub 2}/SiC system. The peak inversion channel mobility measured for lateral 4H-SiC MOSFETs increases following NO passivation.

  14. Measurement of magnetic turbulence structure and nonlinear mode coupling of tearing fluctuations in the Madison Symmetric Torus reversed field pinch edge

    SciTech Connect (OSTI)

    Assadi, S.

    1994-01-01

    Linear and nonlinear magnetohydrodynamic (MHD) stability of current-driven modes are studied in the MST reversed field pinch. Measured low frequency (f < 35 kHz) magnetic fluctuations are consistent with the global resistive tearing instabilities predicted by 3-D MHD simulations. At frequencies above 35 kHz, the magnetic fluctuations were detected to be localized and externally resonant. Discrete dynamo events, ``sawtooth oscillations,`` have been observed in the experimental RFP plasmas. This phenomenon causes the plasma to become unstable to m = 1 tearing modes. The modes that may be important in different phases of these oscillations are identified. These results then assist in nonlinear studies and also help to interpret the spectral broadening of the measured data during a discrete dynamo event. Three-wave nonlinear coupling of spectral Fourier modes is measured in the MST by applying bispectral analysis to magnetic fluctuations measured at the plasma edge at 64 toroidal locations and 16 poloidal locations, permitting observation of coupling over 8 poloidal and 32 toroidal modes. Comparison to bispectra predicted by resistive MHD computation indicates reasonably good agreement. However, during the crash phase of the sawtooth oscillation the nonlinear coupling is strongly enhanced, concomitant with a broadened k-spectrum. During the sawtooth formation the plasma is undergoing a pure diffusive process. The dynamo only occurs during the sawtooth crash. High frequency activity prior to a sawtooth crash is caused by nonlinear frequency (small-scale) mode coupling. Growth rate and coupling coefficients of toroidal mode spectra are calculated by statistical modeling. Temporal evolution of edge toroidal mode spectra has been predicted by transfer function analysis. The driving sources of electrostatic fields are different than for the magnetic fields. The characteristics of tearing modes can be altered by external field errors and addition of impurities to the plasma.

  15. Apparatus for and method of correcting for astigmatism in a light beam reflected off of a light reflecting surface

    DOE Patents [OSTI]

    Sawicki, R.H.; Sweatt, W.

    1985-11-21

    A technique for adjustably correcting for astigmatism in a light beam is disclosed herein. This technique defines a flat, rectangular light reflecting surface having opposite reinforced side edges and which is resiliently bendable, to a limited extent, into different concave and/or convex cylindrical curvatures about a particular axis and provides for adjustably bending the light reflecting surface into one of different curvatures depending upon the astigmatism to be corrected and for fixedly maintaining the curvature selected. In the embodiment disclosed, the light reflecting surface is adjustably bendable into the selected cylindrical curvature by application of a particular bending moment to the reinforced side edges of the light reflecting surface.

  16. Leaf seal for gas turbine stator shrouds and a nozzle band

    DOE Patents [OSTI]

    Burdgick, Steven Sebastian; Sexton, Brendan Francis

    2002-01-01

    A leaf seal assembly is secured to the trailing edge of a shroud segment for sealing between the shroud segment and the leading edge side wall of a nozzle outer band. The leaf seal includes a circumferentially elongated seal plate biased by a pair of spring clips disposed in a groove along the trailing edge of the shroud segment to maintain the seal plate in engagement with the flange on the leading edge side wall of the nozzle outer band. The leaf seal plate and spring clips receive pins tack-welded to the shroud segment to secure the leaf seal assembly in place.

  17. EVIDENCE AGAINST AN EDGE-ON DISK AROUND THE EXTRASOLAR PLANET, 2MASS 1207 b AND A NEW THICK-CLOUD EXPLANATION FOR ITS UNDERLUMINOSITY

    SciTech Connect (OSTI)

    Skemer, Andrew J.; Close, Laird M.; Szucs, Laszlo; Apai, Daniel; Pascucci, Ilaria; Biller, Beth A.

    2011-05-10

    Since the discovery of the first directly imaged, planetary-mass object, 2MASS 1207 b, several works have sought to explain a disparity between its observed temperature and luminosity. Given its known age, distance, and spectral type, 2MASS 1207 b is underluminous by a factor of {approx}10 ({approx}2.5 mag) when compared to standard models of brown-dwarf/giant-planet evolution. In this paper, we study three possible sources of 2MASS 1207 b's underluminosity. First, we investigate Mohanty et al.'s hypothesis that a near edge-on disk, comprising large, gray-extincting grains, might be responsible for 2MASS 1207 b's underluminosity. After radiative transfer modeling, we conclude that the hypothesis is unlikely due to the lack of variability seen in multi-epoch photometry and unnecessary due to the increasing sample of underluminous brown dwarfs/giant exoplanets that cannot be explained by an edge-on disk. Next, we test the analogous possibility that a spherical shell of dust could explain 2MASS 1207 b's underluminosity. Models containing enough dust to create {approx}2.5 mag of extinction, placed at reasonable radii, are ruled out by our new Gemini/T-ReCS 8.7 {mu}m photometric upper limit for 2MASS 1207 b. Finally, we investigate the possibility that 2MASS 1207 b is intrinsically cooler than the commonly used AMES-DUSTY fits to its spectrum, and thus it is not, in fact, underluminous. New, thick-cloud model grids by Madhusudhan et al. fit 2MASS 1207 b's 1-10 {mu}m spectral energy distribution well, but they do not quite fit its near-infrared spectrum. However, we suggest that with some 'tuning', they might be capable of simultaneously reproducing 2MASS 1207 b's spectral shape and luminosity. In this case, the whole class of young, underluminous brown dwarfs/giant exoplanets might be explained by atmospheres that are able to suspend thick, dusty clouds in their photospheres at temperatures lower than field brown dwarfs.

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

    SciTech Connect (OSTI)

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

    2010-07-05

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

  19. DNA origami with Complex Curvatures in 3D

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    for Bio-inspired Solar Fuel Production Professors Hao Yan and Yan Liu are involved in Subtask 2 working on design of artificial water oxidation catalyst for hydrogen production. ...

  20. Sigma models with negative curvature (Journal Article) | DOE...

    Office of Scientific and Technical Information (OSTI)

    Elizabeth E. ; Manohar, Aneesh V. Publication Date: 2016-05-01 OSTI Identifier: 1242323 GrantContract Number: SC0009919 Type: Published Article Journal Name: Physics Letters. ...