WorldWideScience

Sample records for blue ribbon task

  1. Blue Ribbon Panel Report

    Science.gov (United States)

    An NCI Cancer Currents blog by the NCI acting director thanking the cancer community for contributing to the Cancer Moonshot Blue Ribbon Panel report, which was presented to the National Cancer Advisory Board on September 7.

  2. Geothermal Technologies Program Blue Ribbon Panel Recommendations

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2011-06-17

    The Geothermal Technologies Program assembled a geothermal Blue Ribbon Panel on March 22-23, 2011 in Albuquerque, New Mexico for a guided discussion on the future of geothermal energy in the United States and the role of the DOE Program. The Geothermal Blue Ribbon Panel Report captures the discussions and recommendations of the experts. An addendum is available here: http://www.eere.energy.gov/geothermal/pdfs/gtp_blue_ribbon_panel_report_addendum10-2011.pdf

  3. Blue Ribbon Panel Report - BRP - Cancer Moonshot

    Science.gov (United States)

    The Blue Ribbon Panel Report outlines 10 recommendations to accelerate progress against cancer. The panel was established to ensure that the Cancer Moonshot's approaches are grounded in the best science.

  4. Blue Ribbon Panel 2016 Video Playlist

    Science.gov (United States)

    Blue Ribbon Panel members discuss recommendations from the panel report that was presented to the National Cancer Advisory Board on September 7, 2016. The playlist includes an overview video and 10 videos on the specific recommendations.

  5. 77 FR 9707 - U.S. Antarctic Program Blue Ribbon Panel Review; Notice of Meeting

    Science.gov (United States)

    2012-02-17

    ..., innovative, affordable, sustainable, and consistent with the Antarctic Treaty. Agenda: Present the Panel with... U.S. Antarctic Program Blue Ribbon Panel Review; Notice of Meeting In accordance with Federal... following meeting: Name: U.S. Antarctic Program Blue Ribbon Panel Review, 76826. Date/Time: March 5, 2012,...

  6. 76 FR 63329 - U.S. Antarctic Program Blue Ribbon Panel Review; Notice of Meeting

    Science.gov (United States)

    2011-10-12

    ..., affordable, sustainable, and consistent with the Antarctic Treaty. Agenda: First meeting of the Panel to... Doc No: 2011-26281] NATIONAL SCIENCE FOUNDATION U.S. Antarctic Program Blue Ribbon Panel Review... National Science Foundation announces the following meeting: Name: U.S. Antarctic Program Blue Ribbon...

  7. 77 FR 1743 - U.S. Antarctic Program Blue Ribbon Panel; Notice of Meeting

    Science.gov (United States)

    2012-01-11

    ... sound, safe, innovative, affordable, sustainable, and consistent with the Antarctic Treaty. Agenda... U.S. Antarctic Program Blue Ribbon Panel; Notice of Meeting In accordance with Federal Advisory...: Name: U.S. Antarctic Program Blue Ribbon Panel Review, 76826. Date/Time: January 24, 2012, 8 a.m. to...

  8. 77 FR 20852 - U.S. Antarctic Program Blue Ribbon Panel Review; Notice of Meeting

    Science.gov (United States)

    2012-04-06

    ... the Antarctic Treaty. Agenda: Present the Panel with additional programmatic information related to... U.S. Antarctic Program Blue Ribbon Panel Review; Notice of Meeting In accordance with Federal... following meeting: Name: U.S. Antarctic Program Blue Ribbon Panel Review, 76826. Date/Time: April 20,...

  9. 75 FR 57898 - NIST Blue Ribbon Commission on Management and Safety-II

    Science.gov (United States)

    2010-09-23

    ... sector experience in one or more of the following areas: (a) Management and organizational structure; (b... National Institute of Standards and Technology NIST Blue Ribbon Commission on Management and Safety--II... establishment of the NIST Blue Ribbon Commission on Management and Safety--II and Notice of Open...

  10. 75 FR 10791 - Blue Ribbon Commission on America's Nuclear Future

    Science.gov (United States)

    2010-03-09

    ... about the history and current status of spent nuclear fuel and high-level waste disposal in the United... to include presentations on the history of efforts to dispose of civilian light- water reactor spent... Ribbon Commission on America's Nuclear Future AGENCY: Department of Energy, Office of Nuclear...

  11. 76 FR 1608 - Blue Ribbon Commission on America's Nuclear Future

    Science.gov (United States)

    2011-01-11

    ... Ribbon Commission on America's Nuclear Future AGENCY: Department of Energy, Office of Nuclear Energy... and nuclear waste. The Commission is scheduled to submit a draft report to the Secretary of Energy by... to CommissionDFO@nuclear.energy.gov , or post comments on the Commission Web site at...

  12. 75 FR 25850 - Blue Ribbon Commission on America's Nuclear Future

    Science.gov (United States)

    2010-05-10

    ... Ribbon Commission on America's Nuclear Future AGENCY: Department of Energy, Office of Nuclear Energy...- 0544; e-mail CommissionDFO@nuclear.energy.gov . Additional information may also be available at http... to CommissionDFO@nuclear.energy.gov , or post comments on the Commission Web site at...

  13. 75 FR 66766 - NIAID Blue Ribbon Panel Meeting on Adjuvant Discovery and Development

    Science.gov (United States)

    2010-10-29

    ... discovery, development and clinical evaluation of adjuvants for use with preventive vaccines. NIAID has developed a draft Strategic Plan and Research Agenda for Adjuvant Discovery and Development, which... HUMAN SERVICES NIAID Blue Ribbon Panel Meeting on Adjuvant Discovery and Development Notice is...

  14. A Quantitative Examination of the Educational Technology Characteristics of Ohio Schools and Their Blue Ribbon Status

    Science.gov (United States)

    Goon, Dean A.

    2012-01-01

    The purpose of this study was to analyze data from Ohio schools and the frequency of use of educational technology, a teacher's comfort level using technology, and a teacher's beliefs about the effect of educational technology on teaching and learning based upon the school's Blue Ribbon award status. The study used an ex-post facto, quantitative…

  15. A Quantitative Examination of the Educational Technology Characteristics of Ohio Schools and Their Blue Ribbon Status

    Science.gov (United States)

    Goon, Dean A.

    2012-01-01

    The purpose of this study was to analyze data from Ohio schools and the frequency of use of educational technology, a teacher's comfort level using technology, and a teacher's beliefs about the effect of educational technology on teaching and learning based upon the school's Blue Ribbon award status. The study used an ex-post facto,…

  16. 75 FR 54640 - Notice of a Meeting of a Working Group of the NIH Blue Ribbon Panel

    Science.gov (United States)

    2010-09-08

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health Notice of a Meeting of a Working Group of the NIH Blue Ribbon Panel The purpose of this notice is to inform the public about a meeting of the NIH Blue...

  17. 76 FR 61719 - Notice of a meeting of a working group of the NIH Blue Ribbon Panel

    Science.gov (United States)

    2011-10-05

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health Notice of a meeting of a working group of the NIH Blue Ribbon Panel The purpose of this notice is to inform the public about a meeting of the NIH Blue...

  18. Many-Task Computing and Blue Waters

    CERN Document Server

    Katz, Daniel S; Zhang, Zhao; Wilde, Michael; Wozniak, Justin M

    2012-01-01

    This report discusses many-task computing (MTC) generically and in the context of the proposed Blue Waters systems, which is planned to be the largest NSF-funded supercomputer when it begins production use in 2012. The aim of this report is to inform the BW project about MTC, including understanding aspects of MTC applications that can be used to characterize the domain and understanding the implications of these aspects to middleware and policies. Many MTC applications do not neatly fit the stereotypes of high-performance computing (HPC) or high-throughput computing (HTC) applications. Like HTC applications, by definition MTC applications are structured as graphs of discrete tasks, with explicit input and output dependencies forming the graph edges. However, MTC applications have significant features that distinguish them from typical HTC applications. In particular, different engineering constraints for hardware and software must be met in order to support these applications. HTC applications have tradition...

  19. Blue Ribbon Commission on America's Nuclear Future: Report to the Secretary of Energy

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-01-01

    Preamble The Blue Ribbon Commission on America’s Nuclear Future (BRC) was formed by the Secretary of Energy at the request of the President to conduct a comprehensive review of policies for managing the back end of the nuclear fuel cycle and recommend a new strategy. It was co-chaired by Rep. Lee H. Hamilton and Gen. Brent Scowcroft. Other Commissioners are Mr. Mark H. Ayers, the Hon. Vicky A. Bailey, Dr. Albert Carnesale, Sen. Pete Domenici, Ms. Susan Eisenhower, Sen. Chuck Hagel, Mr. Jonathan Lash, Dr. Allison M. Macfarlane, Dr. Richard A. Meserve, Dr. Ernest J. Moniz, Dr. Per Peterson, Mr. John Rowe, and Rep. Phil Sharp. The Commission and its subcommittees met more than two dozen times between March 2010 and January 2012 to hear testimony from experts and stakeholders, to visit nuclear waste management facilities in the United States and abroad, and to discuss the issues identified in its Charter. Additionally, in September and October 2011, the Commission held five public meetings, in different regions of the country, to hear feedback on its draft report. A wide variety of organizations, interest groups, and individuals provided input to the Commission at these meetings and through the submission of written materials. Copies of all of these submissions, along with records and transcripts of past meetings, are available at the BRC website (www.brc.gov). This report highlights the Commission’s findings and conclusions and presents recommendations for consideration by the Administration and Congress, as well as interested state, tribal and local governments, other stakeholders, and the public.

  20. 76 FR 38648 - Availability of the Geothermal Technologies Program Blue Ribbon Panel Report and Request for...

    Science.gov (United States)

    2011-07-01

    ... Albuquerque, New Mexico for a guided discussion on the future of geothermal energy in the United States and... of Energy Efficiency and Renewable Energy Availability of the Geothermal Technologies Program Blue... Department of Energy's (DOE) Office of Energy Efficiency and Renewable Energy (EERE) Geothermal...

  1. Development and evaluation of die materials for use in the growth of silicon ribbons by the inverted ribbon growth process, task 2, LSSA project

    Science.gov (United States)

    Duffy, M. T.; Berkman, S.; Cullen, G. W.; Moss, H. I.

    1977-01-01

    Silicon sessile drop experiments were performed on a variety of commercially available refractory carbides, nitrides, oxides, and borides to examine the potential of these materials for applications involving either direct contact with molten silicon or as substrates for CVD coatings in the fabrication of dies and crucibles for containing molten silicon. Simultaneous experiments were also conducted with CVD layers of SiC, Si3N4, and SiOxNy. Silicon nitride layers, deposited with NH3:SiH4 ratios ranging from 100:1 down to 5:1, were examined in sessile drop experiments to determine if the layers are degraded as a result of using lower reagent ratios. Preliminary experiments were undertaken on the stability of CVD Si3N4 near the melting point of silicon. Silicon ribbon segments were grown from vitreous carbon dies which had been coated with CVD Si3N4. Depending upon the purity of the die materials, ribbon resistivity values up to 40 Omega cm were obtained.

  2. Ribbon crystals.

    Directory of Open Access Journals (Sweden)

    Jakob Bohr

    Full Text Available A repetitive crystal-like pattern is spontaneously formed upon the twisting of straight ribbons. The pattern is akin to a tessellation with isosceles triangles, and it can easily be demonstrated with ribbons cut from an overhead transparency. We give a general description of developable ribbons using a ruled procedure where ribbons are uniquely described by two generating functions. This construction defines a differentiable frame, the ribbon frame, which does not have singular points, whereby we avoid the shortcomings of the Frenet-Serret frame. The observed spontaneous pattern is modeled using planar triangles and cylindrical arcs, and the ribbon structure is shown to arise from a maximization of the end-to-end length of the ribbon, i.e. from an optimal use of ribbon length. The phenomenon is discussed in the perspectives of incompatible intrinsic geometries and of the emergence of long-range order.

  3. Ribbon Crystals

    DEFF Research Database (Denmark)

    Bohr, Jakob; Markvorsen, Steen

    2013-01-01

    A repetitive crystal-like pattern is spontaneously formed upon the twisting of straight ribbons. The pattern is akin to a tessellation with isosceles triangles, and it can easily be demonstrated with ribbons cut from an overhead transparency. We give a general description of developable ribbons...

  4. Development and Evaluation of Die Materials for Use in the Growth of Silicon Ribbons by the Inverted Ribbon Growth Process. Task 2: LSSA Project

    Science.gov (United States)

    Duffy, M. T.; Berkman, S.; Moss, H. I.; Cullen, G. W.

    1978-01-01

    Several ribbon growth experiments were performed from V-shaped dies coated with CVD Si3N4. The most significant result was the ability to perform five consecutive growth runs from the same die without mechanical degradation of the die through temperature cycling. The die was made from vitreous carbon coated with CVD Si3N4. Silicon oxynitride, Si2N2O, was examined with respect to thermal stability in contact with molten silicon. The results of X-ray analysis indicate that this material is converted to both alpha - and beta-Si3N4 in the presence of molten silicon. Experiments on the stability of CVD SiOxNy shoe that this material can be maintained in contact with molten silicon (sessile drop test) for greater than 30 h at 1450 C without total decompositon. These layers are converted mainly to beta-Si3N4.

  5. Laser-zone growth in a Ribbon-To-Ribbon, RTR, process silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

    Science.gov (United States)

    Gurtler, R. W.; Baghdadi, A.

    1977-01-01

    A ribbon-to-ribbon process was used for routine growth of samples for analysis and fabrication into solar cells. One lot of solar cells was completely evaluated: ribbon solar cell efficiencies averaged 9.23% with a highest efficiency of 11.7%. Spherical reflectors have demonstrated significant improvements in laser silicon coupling efficiencies. Material analyses were performed including silicon photovoltage and open circuit photovoltage diffusion length measurements, crystal morphology studies, modulus of rupture measurements, and annealing/gettering studies. An initial economic analysis was performed indicating that ribbon-to-ribbon add-on costs of $.10/watt might be expected in the early 1980's.

  6. Laser-zone growth in a Ribbon-To-Ribbon (RTR) process. Silicon sheet growth development for the large area sheet task of the low-cost solar array project

    Science.gov (United States)

    Baghdadi, A.; Gurtler, R. W.; Legge, R.; Sopori, B.; Ellis, R. J.

    1978-01-01

    A new calculation of the effects of thermal stresses during growth on silicon ribbon quality is reported. Thermal stress distributions are computed for ribbon growth under a variety of temperature profiles. A growth rate of 55 cu cm/min with a single ribbon was achieved. The growth of RTR ribbon with a fairly uniform parallel dendritic structure was demonstrated. Results with two approaches were obtained for reducing the Mo impurity level in polycrystalline feedstock. Coating the Mo substrate with Si3N4 does not effect thermal shear separation of the polyribbon; this process shows promise of improving cell efficiency and also increasing the useful life of the molybdenum substrate. A number of solar cells were fabricated on RTR silicon grown from CVD feedstock.

  7. NO y Blue Ribbon panel

    Science.gov (United States)

    Crosley, David R.

    1996-01-01

    Total NOy was determined on the Pacific Exploratory Mission-West A using two separate instruments, one operated by Georgia Institute of Technology and one by Nagoya University. The two data sets exhibited significant disagreement, with no systematic correlation, and differences often a factor of 2 or more. Additionally, regardless of data set chosen, the total NOy was much greater than the sum of its components measured separately. A panel was convened by NASA in July 1993 to examine these conflicting datasets and the question of "missing NOy" on this mision. This paper reports the conclusions and recommendations from the panel.

  8. Laser-zone growth in a Ribbon-To-Ribbon (RTR) process. Silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

    Science.gov (United States)

    Gurtler, R. W.; Baghdadi, A.; Legge, R.; Sopori, B.; Ellis, R. J.

    1977-01-01

    The Ribbon-to-Ribbon (RTR) approach to silicon ribbon growth is investigated. An existing RTR apparatus is to be upgraded to its full capabilities and operated routinely to investigate and optimize the effects of various growth parameters on growth results. A new RTR apparatus was constructed to incorporate increased capabilities and improvements over the first apparatus and to be capable of continuous growth. New high power lasers were implemented and this led to major improvements in growth velocity -- 4 inch/min. growth has been demonstrated. A major step in demonstration of the full feasibility of the RTR process is reported in the demonstration of RTR growth from CVD polyribbon rather than sliced polyribbon ingots. Average solar cell efficiencies of greater than 9% and a best cell efficiency of 11.7% are reported. Processing was shown to provide a substantial improvement in material minority carrier diffusion length. An economic analysis is reported which treats both the polyribbon fabrication and RTR processes.

  9. Laser-zone Growth in a Ribbon-to-ribbon (RTR) Process Silicon Sheet Growth Development for the Large Area Silicon Sheet Task of the Low Cost Solar Array Project

    Science.gov (United States)

    Baghdadi, A.; Gurtler, R. W.; Legge, R.; Sopori, B.; Rice, M. J.; Ellis, R. J.

    1979-01-01

    A technique for growing limited-length ribbons continually was demonstrated. This Rigid Edge technique can be used to recrystallize about 95% of the polyribbon feedstock. A major advantage of this method is that only a single, constant length silicon ribbon is handled throughout the entire process sequence; this may be accomplished using cassettes similar to those presently in use for processing Czochralski waters. Thus a transition from Cz to ribbon technology can be smoothly affected. The maximum size being considered, 3 inches x 24 inches, is half a square foot, and will generate 6 watts for 12% efficiency at 1 sun. Silicon dioxide has been demonstrated as an effective, practical diffusion barrier for use during the polyribbon formation.

  10. Visions of Reform: Implications for the Education Profession. The Report of the ATE Blue Ribbon Task Force.

    Science.gov (United States)

    Association of Teacher Educators, Reston, VA.

    This report presents an analysis and implications of three current and major education reform reports. Part one reviews and analyzes the National Council for Accreditation of Teacher Education (NCATE) redesign, the Holmes Group report, and the report of the Carnegie Forum on Education and the Economy. Part two points out the implications which the…

  11. Ribbon Turbulence

    CERN Document Server

    Venaille, Antoine; Vallis, Geoffrey K

    2014-01-01

    We investigate the non-linear equilibration of a two-layer quasi-geostrophic flow in a channel forced by an imposed unstable zonal mean flow, paying particular attention to the role of bottom friction. In the limit of low bottom friction, classical theory of geostrophic turbulence predicts an inverse cascade of kinetic energy in the horizontal with condensation at the domain scale and barotropization on the vertical. By contrast, in the limit of large bottom friction, the flow is dominated by ribbons of high kinetic energy in the upper layer. These ribbons correspond to meandering jets separating regions of homogenized potential vorticity. We interpret these result by taking advantage of the peculiar conservation laws satisfied by this system: the dynamics can be recast in such a way that the imposed mean flow appears as an initial source of potential vorticity levels in the upper layer. The initial baroclinic instability leads to a turbulent flow that stirs this potential vorticity field while conserving the...

  12. Laser-zone growth in a ribbon-to-ribbon (RTR) process silicon sheet growth development for the large area silicon sheet task of the Low Cost Solar Array Project. Technical quarterly report No. 10, January 1-March 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Baghdadi, A.; Gurtler, R.W.; Legge, R.; Sopori, B.; Rice, M.J.; Ellis, R.J.

    1979-01-01

    This quarter has witnessed appreciable progress in achieving high efficiency on RTR solar cells, with an average efficiency of 9.1% on the most recent lot. The best cell to date has a measured efficiency of 11.3%. A new technique for growing limited-length ribbons continually has been demonstrated. This Rigid Edge technique can be used to recrystallize about 95% of the polyribbon feedstock. A major advantage of this method is that only a single, constant length silicon ribbon is handled throughout the entire process sequence; this may be accomplished using cassettes similar to those presently in use for processing Czochralski wafers. Thus a transition from Cz to ribbon technology can be smoothly affected. The maximum size being considered, 3'' x 24'', is half a square foot and will generate 6 watts for 12% efficiency at 1 sun. Silicon dioxide has been demonstrated as an effective, practical diffusion barrier for use during the polyribbon formation. Two different approaches for using the silicon dioxide are being pursued.

  13. Arrow ribbon graphs

    CERN Document Server

    Bradford, Robert; Chmutov, Sergei

    2011-01-01

    We introduce an additional structure on ribbon graphs, arrow structure. We extend the Bollob\\'as-Riordan polynomial to ribbon graph with this structure. The extended polynomial satisfies the contraction-deletion relations and naturally behaves with respect to the partial duality of ribbon graphs. We construct an arrow ribbon graph from a virtual link whose extended Bollob\\'as-Riordan polynomial specializes to the arrow polynomial of the virtual link recently introduced by H.Dye and L.Kauffman. This result generalizes the classical Thistlethwaite theorem to the arrow polynomial of virtual links.

  14. Laser-zone growth in a Ribbon-to-Ribbon (RTR) process. Silicon sheet growth development for the Large Area Silicon Sheet Task of the Low-Cost Silicon Solar Array Project. Technical quarterly report No. 7, January 1--March 31, 1978. Motorola report No. 2256/9

    Energy Technology Data Exchange (ETDEWEB)

    Gurtler, R W; Baghdadi, A; Legge, R; Sopori, B; Ellis, R J

    1978-01-01

    Substantial progress has been made both in crystal growth and in processing. A growth rate of 12.5 cm/min with 2 cm wide ribbon was achieved. This high growth-rate ribbon has a dendritic structure. The maximum non-dentritic growth rate was increased to 8 to 9 cm/min by using active cooling (inert gas jets) to steepen the postheater temperature gradient. Also, RTR ribbon was grown from 2.5 cm wide CVD polycrystalline feedstock. Doped CVD feedstock can now be grown in widths from 1 in. to 3 in., and thicknesses from 125 ..mu..m to 250 ..mu..m. The poly ribbon thickness is uniform within +-5 percent along the length of the ribbon. First attempts to grow 5 cm wide ribbon from CVD feedstock were only partially successful, due to buckling in the ribbon prior to crystallization. This buckling creates both longitudinal and lateral curvatures in the ribbon. The curvature is often so great that the sample cannot pass through the 0.1 in. wide slot of the postheater. The probable cause for this buckling is the non-ideal longitudinal temperature distribution. The temperature profile must be controlled in the feedstock ribbon (as well as in the growing ribbon) in order to overcome this problem. Solar cells were fabricated on dendritic ribbon. Preliminary measurements indicate that their performance is at least as high as cells fabricated on non-dendritic substrates.

  15. Fine structure of flare ribbons and evolution of electric currents

    CERN Document Server

    Sharykin, I N

    2014-01-01

    Emission of solar flares across the electromagnetic spectrum is often observed in the form of two expanding ribbons. The standard flare model explains the flare ribbons as footpoints of magnetic arcades, emitting due to interaction of energetic particles with the chromospheric plasma. However, the physics of this interaction and properties of the accelerated particles are still unknown. We present results of multiwavelength observations of C2.1 flare of August 15, 2013, observed with New Solar Telescope (NST) of Big Bear Solar Observatory, Solar Dynamics Observatory (SDO), GOES and FERMI spacecraft. The observations reveal previously unresolved sub-arcsecond structure of the flare ribbons in regions of strong magnetic field consisting from numerous small-scale bright knots. We observe red-blue asymmetry of H alpha flare ribbons with a width as small as 100 km. We discuss the relationship between the ribbons and vertical electric currents estimated from vector magnetograms, and show that Joule heating can be r...

  16. Slender-ribbon theory

    CERN Document Server

    Koens, Lyndon

    2016-01-01

    Ribbons are long narrow strips possessing three distinct material length scales (thickness, width, and length) which allow them to produce unique shapes unobtainable by wires or filaments. For example when a ribbon has half a twist and is bent into a circle it produces a M\\"obius strip. Significant effort has gone into determining the structural shapes of ribbons but less is know about their behavior in viscous fluids. In this paper we determine, asymptotically, the leading-order hydrodynamic behavior of a slender ribbon in Stokes flows. The derivation, reminiscent of slender-body theory for filaments, assumes that the length of the ribbon is much larger than its width, which itself is much larger than its thickness. The final result is an integral equation for the force density on a mathematical ruled surface, termed the ribbon plane, located inside the ribbon. A numerical implementation of our derivation shows good agreement with the known hydrodynamics of long flat ellipsoids, and successfully captures the...

  17. Ribbon Seal Distribution Map

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains GIS layers that depict the known spatial distributions (i.e., ranges) and reported breeding areas of ribbon seals (Histriophoca fasciata). It...

  18. The Ribbon Laser

    Energy Technology Data Exchange (ETDEWEB)

    Feit, M D; Beach, R J; Brasure, L D; Payne, S A; Page, R H; Wilcox, R

    2001-04-18

    A new scalable fiber laser approach is described and modeled, based on phase-locking multiple gain cores in an antiguided structure. In essence, the waveguide is comprised of a periodic sequence of gain-loaded and no-gain segments having uniform refractive index (referred to as the ''ribbon'') encapsulated within a reduced index cladding region. Our calculations reveal that the constant index profile within the ribbon structure provides optimal mode discrimination; the refractive index must be constant within {+-}0.001 to ensure single-mode operation for a 5-core design. Periodic variation in refractive index and gain of the ribbon laser lead to the emergence of a photonic bandgap, in analogy to so-called ''holey fibers''. Our constant index design, together with the periodic gain profile, may be described as a photonic metal.

  19. Sculpturing Surfaces with Cartan Ribbons

    DEFF Research Database (Denmark)

    Raffaelli, Matteo; Bohr, Jakob; Markvorsen, Steen

    2016-01-01

    Using the concepts of Cartan development and rolling from differential geometry we develop a method for sculpturing any surface with the use of Cartan ribbons.......Using the concepts of Cartan development and rolling from differential geometry we develop a method for sculpturing any surface with the use of Cartan ribbons....

  20. Graphene nano-ribbon waveguides

    CERN Document Server

    He, S; He, Y

    2013-01-01

    Graphene as a one-atom-thick platform for infrared metamaterial plays an important role in optical science and engineering. Here we study the unique properties of some plasmonic waveguides based on graphene nano-ribbon. It is found that a graphene ribbon of finite width leads to the occurrence of coupled edge mode. The single-mode region of a single freestanding graphene ribbon is identified at a fixed frequency of 30 THz. A low-loss waveguide structure, consisting of a graphene layer, a silica buffer layer and silicon substrate is proposed to reduce the propagation loss and obtain a high figure of merit for future integration of waveguide devices. Furthermore, two coupled ribbon configurations, namely, side-side coupling and top-bottom coupling, are investigated. As a device example, a nano-ring cavity of ultra-small size is designed.

  1. EFG Ribbon Technology

    Science.gov (United States)

    Schwirtlich, I. A.

    Since the beginning of solar cell development based on crystalline silicon, there have been efforts to produce wafers directly from the melt instead of through crystallization of ingots. Ingots require slicing into the blocs and wafers which form the basis of solar cells. In the last 30 years, several dozen processes have been published that describe a variety of concepts. Only few of these processes could be developed to an acceptable degree of technical maturity. Among those successful technologies are the Dendritic Web process, the Edge Supported Pulling (ESP) process and the Edge-Defined-Film-Fed-Growth (EFG) process. The EFG Process was originally developed by Mobil Solar and, since the mid-1990s, belongs to SCHOTT Solar GmbH and its predecessors, respectively. The Ribbon Growth on Substrate (RGS) process was originally developed by Bayer AG and is now in a pilot project at the ECN, Petten. Considering the past 20 to 30 years, the EFG process has reached the most advanced state in terms of industrialization.

  2. Neuraminidase Ribbon Diagram

    Science.gov (United States)

    2004-01-01

    Ribbons is a program developed at UAB used worldwide to graphically depict complicated protein structures in a simplified format. The program uses sophisticated computer systems to understand the implications of protein structures. The Influenza virus remains a major causative agent for a large number of deaths among the elderly and young children and huge economic losses due to illness. Finding a cure will have a general impact both on the basic research of viral pathologists of fast evolving infectious agents and clinical treatment of influenza virus infection. The reproduction process of all strains of influenza are dependent on the same enzyme neuraminidase. Shown here is a segmented representation of the neuraminidase inhibitor compound sitting inside a cave-like contour of the neuraminidase enzyme surface. This cave-like formation present in every neuraminidase enzyme is the active site crucial to the flu's ability to infect. The space-grown crystals of neuraminidase have provided significant new details about the three-dimensional characteristics of this active site thus allowing researchers to design drugs that fit tighter into the site. Principal Investigator: Dr. Larry DeLucas

  3. Temporal variation of the IBEX Ribbon

    Science.gov (United States)

    Janzen, P. H.

    2015-12-01

    We present a study of the time variation over half a solar cycle of the ENA flux composing the IBEX Ribbon, with the goal of determining how closely the Ribbon's temporal variation matches that of the adjacent globally distributed ENA flux (GDF). A high degree of similarity implies that the Ribbon flux originates in the same heliospheric regions as the GDF, presumably the inner heliosheath. If the Ribbon flux shows a separate time history, then it likely originates elsewhere, possibly in the outer heliosheath or beyond. Determining the source region places strong constraints on Ribbon formation theories. Prior Ribbon studies have either treated the Ribbon and the GDF as static over the mission, or have not attempted to separate the GDF from the Ribbon when looking at time variation.

  4. Laser cleaning of tungsten ribbon

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Aniruddha, E-mail: nontee65@rediffmail.com [Advanced Fuel Fabrication Facility, Bhabha Atomic Research Centre, Tarapur, Maharashtra, 401504 (India); Sonar, V.R.; Das, D.K.; Bhatt, R.B.; Behere, P.G.; Afzal, Mohd.; Kumar, Arun [Advanced Fuel Fabrication Facility, Bhabha Atomic Research Centre, Tarapur, Maharashtra, 401504 (India); Nilaya, J.P.; Biswas, D.J. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, 400085 (India)

    2014-07-01

    Removal of a thin oxide layer from a tungsten ribbon was achieved using the fundamental, second and third harmonic radiation from a Q- switched Nd-YAG laser. It was found that beyond the threshold, oxide removal was achieved at all wavelengths for a wide range of fluence values. The removal mechanism of the oxide layer was found to be critically dependent on both wavelength and fluence of the incident radiation and has been identified as ejection or sublimation. The un-cleaned and cleaned surfaces were analyzed by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS) and atomic force microscopy (AFM). Laser cleaned tungsten ribbons were used in a thermal ionization mass spectrometer (TIMS) to determine isotopic composition of Neodymium atoms.

  5. Domain imaging in FINEMET ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Silveyra, J.M., E-mail: jsilveyra@fi.uba.a [Laboratorio de Solidos Amorfos, INTECIN, Facultad de Ingenieria, UBA-CONICET, Paseo Colon 850, (C1063ACV) Buenos Aires (Argentina); Vlasak, G.; Svec, P.; Janickovic, D. [Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava (Slovakia); Cremaschi, V.J., E-mail: vcremas@gmail.co [Laboratorio de Solidos Amorfos, INTECIN, Facultad de Ingenieria, UBA-CONICET, Paseo Colon 850, (C1063ACV) Buenos Aires (Argentina); Member of Carrera del Investigador, CONICET (Argentina)

    2010-09-15

    The magnetization behaviour of a ferromagnetic material depends on its domain structure, which in turn is largely determined by magnetic anisotropies. In this work, domain patterns were observed by a quite forgotten but still the simplest and the cheapest technique: the Bitter method. A systematic study of the evolution of the domain structure in FINEMET ribbons after thermal annealing is presented, correlating the results with the crystalline structure, magnetostriction and coercivity measurements.

  6. 76 FR 4646 - Blue Ribbon Commission on America's Nuclear Future

    Science.gov (United States)

    2011-01-26

    ... fuel and commercial power reactors, and Navy nuclear fuel. Therefore, the purpose for closing this... nuclear fuel cycle. The Commission will provide advice and make recommendations on issues including... comprehensive review of policies for managing the back end of the nuclear fuel cycle, including all......

  7. 75 FR 81592 - Blue Ribbon Commission on America's Nuclear Future

    Science.gov (United States)

    2010-12-28

    .... EST. ADDRESSES: Augusta Marriott Hotel and Suites, Two Tenth Street, Augusta, GA 30901, (706) 722-8900.... at the Augusta Marriott Hotel and Suites. The Commission will hear presentations and statements from... register to do so beginning at 8 a.m. on January 7, 2011, at the Augusta Marriott Hotel and...

  8. Preventing Freezeup in Silicon Ribbon Growth

    Science.gov (United States)

    Mackintosh, B.

    1983-01-01

    Carefully-shaped heat conductor helps control thermal gradients crucial to growth of single-crystal silicon sheets for solar cells. Ends of die through which silicon sheet is drawn as ribbon from molten silicon. Profiled heat extractor prevents ribbon ends from solidifying prematurely and breaking.

  9. Helicoids, wrinkles, and loops in twisted ribbons.

    Science.gov (United States)

    Chopin, Julien; Kudrolli, Arshad

    2013-10-25

    We investigate the instabilities of a flat elastic ribbon subject to twist under tension and develop an integrated phase diagram of the observed shapes and transitions. We find that the primary buckling mode switches from being localized longitudinally along the length of the ribbon to transverse above a triple point characterized by a crossover tension that scales with ribbon elasticity and aspect ratio. Far from threshold, the longitudinally buckled ribbon evolves continuously into a self-creased helicoid with focusing of the curvature along the triangular edges. Further twist causes an anomalous transition to loops compared with rods due to the self-rigidity induced by the creases. When the ribbon is twisted under high tension, transverse wrinkles are observed due to the development of compressive stresses with higher harmonics for greater width-to-length ratios. Our results can be used to develop functional structures using a wide range of elastic materials and length scales.

  10. Carbon nanotube fiber spun from wetted ribbon

    Science.gov (United States)

    Zhu, Yuntian T; Arendt, Paul; Zhang, Xiefei; Li, Qingwen; Fu, Lei; Zheng, Lianxi

    2014-04-29

    A fiber of carbon nanotubes was prepared by a wet-spinning method involving drawing carbon nanotubes away from a substantially aligned, supported array of carbon nanotubes to form a ribbon, wetting the ribbon with a liquid, and spinning a fiber from the wetted ribbon. The liquid can be a polymer solution and after forming the fiber, the polymer can be cured. The resulting fiber has a higher tensile strength and higher conductivity compared to dry-spun fibers and to wet-spun fibers prepared by other methods.

  11. Growth and characterization of string ribbon

    Energy Technology Data Exchange (ETDEWEB)

    Hanoka, J.I. [Evergreen Solar, Inc., Waltham, MA (United States); Behnin, B.; Michel, J. [Massachusetts Inst. of Technology, Cambridge, MA (United States); Symko, M.; Sopori, B.L. [National Renewable Energy Lab., Golden, CO (United States)

    1995-08-01

    Evergreen Solar, a new photovoltaics company, makes solar cells and modules based on String Ribbon. String Ribbon is a silicon sheet growth method wherein two high temperature strings are pulled through a shallow melt of silicon and a crystalline silicon sheet then grows between the two strings. The strings serve to stabilize the edges of the growing silicon sheet. The growth process is primarily meniscus controlled and, compared to other silicon ribbon growth methods such as d-web and EFG, relatively insensitive to temperature fluctuations as great as {+-}10{degrees}C. Growth speed is about 2 cm/minute.

  12. Research on reasonable winding angle of ribbons of Flat Steel Ribbon Wound Pressure Vessel

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Flat Steel Ribbon Wound Pressure Vessels (FSRWPVs) are used in many important industry areas. There is no such kind of pressure vessel exploding on operation for its reasonable structure design. Many explosion experiments on Flat Steel Ribbon Wound Pressure Vessel showed that their limited load pressure is related to the winding angle of the steel ribbons.FSRWPVs with reasonable winding angle have better security and lower cost. Reasonable angels given at the end of this paper facilitate engineering design.

  13. Microscale Flow Dynamics of Ribbons and Sheets

    CERN Document Server

    Montenegro-Johnson, Thomas D; Lauga, Eric

    2016-01-01

    Numerical study of the hydrodynamics of thin sheets and ribbons presents difficulties associated with resolving multiple length scales. To circumvent these difficulties, asymptotic methods have been developed to describe the dynamics of slender fibres and ribbons. However, such theories entail restrictions on the shapes that can be studied, and often break down in regions where standard boundary element methods are still impractical. In this paper we develop a regularised stokeslet method for ribbons and sheets in order to bridge the gap between asymptotic and boundary element methods. The method is validated against the analytical solution for plate ellipsoids, as well as the dynamics of ribbon helices and an experimental microswimmer. We then demonstrate the versatility of this method by calculating the flow around a double helix, and the swimming dynamics of a microscale "magic carpet".

  14. On the Geometry of the IBEX Ribbon

    CERN Document Server

    Sylla, Adama

    2015-01-01

    The Energetic Neutral Atom (ENA) full-sky maps obtained with the Interstellar Boundary Explorer (IBEX) show an unexpected bright narrow band of increased intensity. This so-called ENA ribbon results from charge exchange of interstellar neutral atoms with protons in the outer heliosphere or beyond. Amongst other hypotheses it has been argued that this ribbon may be related to a neutral density enhancement, or H-wave, in the local interstellar medium. Here we quantitatively demonstrate, on the basis of an analytical model of the principal large-scale heliospheric structure, that this scenario for the ribbon formation leads to results that are fully consistent with the observed location of the ribbon in the full-sky maps at all energies detected with high-energy sensor IBEX-Hi.

  15. LISM Inhomogeneities and the IBEX Ribbon

    Science.gov (United States)

    Sylla, Adama; Fichtner, Horst

    2016-04-01

    The Energetic Neutral Atom (ENA) full-sky maps obtained with the Interstellar Boundary Explorer (IBEX) show an unexpected bright narrow band of increased intensity. This so-called ENA ribbon results from charge exchange of interstellar neutral atoms with protons in the inner heliosheath and/or beyond. According to a recent hypothesis this ribbon may be related to a neutral density enhancement, a so-called H-wave, in the local interstellar medium. It is shown on the basis of an analytical model of the principal large-scale heliospheric structure that this scenario for the ribbon formation is consistent with the observed location of the ribbon in the full-sky maps at all energies detected with high-energy sensor IBEX-Hi.

  16. Black Silicon Solar Cells with Black Ribbons

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io;

    2016-01-01

    We present the combination of mask-less reactive ion etch (RIE) texturing and blackened interconnecting ribbons as a method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon made by mask-less reactive ion etching has total, average...... reflectance below 0.5% across a 156x156 mm2 silicon (Si) wafer. Black interconnecting ribbons were realized by oxidizing copper resulting in reflectance below 3% in the visible wavelength range. Screen-printed Si solar cells were realized on 156x156 mm2 black Si substrates with resulting efficiencies...... in the range 15.7-16.3%. The KOH-textured reference cell had an efficiency of 17.9%. The combination of black Si and black interconnecting ribbons may result in aesthetic, all-black panels based on conventional, front-contacted silicon solar cells....

  17. Flare Ribbon Expansion and Energy Release

    Indian Academy of Sciences (India)

    Ayumi Asai; Takaaki Yokoyama; Masumi Shimojo; Satoshi Masuda; Kazunari Shibata

    2006-06-01

    We report a detailed examination about the relationship between the evolution of the H flare ribbons and the released magnetic energy during the April 10 2001 flare. In the H images, several bright kernels are observed in the flare ribbons. We identified the conjugated footpoints, by analyzing the lightcurves at each H kernels, and showed their connectivities during the flare. Then, based on the magnetic reconnection model, we calculated quantitatively the released energy by using the photospheric magnetic field strengths and separation speeds of the H flare ribbons. Finally, we examined the downward motions which are observed at the H kernels. We found that the stronger the red-asymmetry tends to be associated with the brighter the H kernel.

  18. Low-loss terahertz ribbon waveguides

    Science.gov (United States)

    Yeh, Cavour; Shimabukuro, Fred; Siegel, Peter H.

    2005-10-01

    The submillimeter wave or terahertz (THz) band (1 mm-100 µm) is one of the last unexplored frontiers in the electromagnetic spectrum. A major stumbling block hampering instrument deployment in this frequency regime is the lack of a low-loss guiding structure equivalent to the optical fiber that is so prevalent at the visible wavelengths. The presence of strong inherent vibrational absorption bands in solids and the high skin-depth losses of conductors make the traditional microstripline circuits, conventional dielectric lines, or metallic waveguides, which are common at microwave frequencies, much too lossy to be used in the THz bands. Even the modern surface plasmon polariton waveguides are much too lossy for long-distance transmission in the THz bands. We describe a concept for overcoming this drawback and describe a new family of ultra-low-loss ribbon-based guide structures and matching components for propagating single-mode THz signals. For straight runs this ribbon-based waveguide can provide an attenuation constant that is more than 100 times less than that of a conventional dielectric or metallic waveguide. Problems dealing with efficient coupling of power into and out of the ribbon guide, achieving low-loss bends and branches, and forming THz circuit elements are discussed in detail. One notes that active circuit elements can be integrated directly onto the ribbon structure (when it is made with semiconductor material) and that the absence of metallic structures in the ribbon guide provides the possibility of high-power carrying capability. It thus appears that this ribbon-based dielectric waveguide and associated components can be used as fundamental building blocks for a new generation of ultra-high-speed electronic integrated circuits or THz interconnects.

  19. Reducing the magnetic losses of amorphous ribbon

    Energy Technology Data Exchange (ETDEWEB)

    Raybould, D.; Das, S.K. [AlliedSignal Inc., Morristown, NJ (United States). Aerospace Technol. Team; Meola, M.; Bye, R. [AlliedSignal Inc., Amorphous Metals, Morristown, NJ 07962-1021 (United States)

    1998-01-30

    Amorphous alloys have lower magnetization losses than silicon steel and are therefore used as the cores of high-efficiency electrical transformers. Laser scribing the amorphous alloys using a very low power, so as not to melt the surface, results in an appreciable decrease in core loss with no decrease in measurable induction. A 2-5 mm line spacing appears optimum. Scribing prior to or after magnetic annealing results in similar properties, although the former requires a slightly higher laser power. Excimer and YAG lasers using optimized parameters both result in identical magnetic properties, but the optimum morphology of the scribed line is different for the two types of laser. For 25 {mu}m thick ribbon, a 29% decrease in core loss is obtained with no increase in exciting power. For thick, 50 {mu}m ribbon, properties superior to those of conventional 25 {mu}m ribbon are achievable, the core loss being decreased nearly 50% with no increase in exciting power. Thick ribbon with these properties could decrease the fabrication cost, while increasing the efficiency of power transformers. (orig.) 15 refs.

  20. Localized modes in nonlinear binary kagome ribbons

    OpenAIRE

    Belicev, P. P.; Gligoric, G.; Radosavljevic, A; Maluckov, A.; Stepic, M.; Vicencio, R. A.; Johansson, Magnus

    2015-01-01

    The localized mode propagation in binary nonlinear kagome ribbons is investigated with the premise to ensure controlled light propagation through photonic lattice media. Particularity of the linear system characterized by the dispersionless flat band in the spectrum is the opening of new minigaps due to the "binarism." Together with the presence of nonlinearity, this determines the guiding mode types and properties. Nonlinearity destabilizes the staggered rings found to be nondiffracting in t...

  1. Faceted ceramic fibers, tapes or ribbons and epitaxial devices therefrom

    Science.gov (United States)

    Goyal, Amit

    2013-07-09

    A crystalline article includes a single-crystal ceramic fiber, tape or ribbon. The fiber, tape or ribbon has at least one crystallographic facet along its length, which is generally at least one meter long. In the case of sapphire, the facets are R-plane, M-plane, C-plane or A-plane facets. Epitaxial articles, including superconducting articles, can be formed on the fiber, tape or ribbon.

  2. Faceted ceramic fibers, tapes or ribbons and epitaxial devices therefrom

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, Amit (Knoxville, TN)

    2012-07-24

    A crystalline article includes a single-crystal ceramic fiber, tape or ribbon. The fiber, tape or ribbon has at least one crystallographic facet along its length, which is generally at least one meter long. In the case of sapphire, the facets are R-plane, M-plane, C-plane or A-plane facets. Epitaxial articles, including superconducting articles, can be formed on the fiber, tape or ribbon.

  3. Kind of Blue - Europa Blues

    DEFF Research Database (Denmark)

    Mortensen, Tore; Kirkegaard, Peter

    2009-01-01

    Bidraget reflekterer over sammenhænge mellem to værker fra det musikalske og litterære område. Det drejer sig om Miles Davis' Kind of Blue fra 1959 og Arne Dahls krimi, Europa Blues fra 2001. Den grundlæggende indfaldsvinkel er det performative, den frie, men samtidigt disciplinerede musikalske...

  4. Dry Ribbon for Heated Head Automated Fiber Placement

    Science.gov (United States)

    Hulcher, A. Bruce; Marchello, Joseph M.; Hinkley, Jeffrey A.; Johnston, Norman J.; Lamontia, Mark A.

    2000-01-01

    Ply-by-ply in situ processes involving automated heated head deposition are being developed for fabrication of high performance, high temperature composite structures from low volatile content polymer matrices. This technology requires (1) dry carbon fiber towpreg, (2) consolidation of towpreg to quality, placement-grade unidirectional ribbon or tape, and (3) rapid, in situ, accurate, ply-by-ply robotic placement and consolidation of this material to fabricate a composite structure. In this study, the physical properties of a candidate thermoplastic ribbon, PIXA/IM7, were evaluated and screened for suitability in robotic placement. Specifically, towpreg was prepared from PIXA powder. Various conditions (temperatures) were used to convert the powder-coated towpreg to ribbons with varying degrees of processability. Ribbon within preset specifications was fabricated at 3 temperatures: 390, 400 and 410 C. Ribbon was also produced out-of-spec by purposely overheating the material to a processing temperature of 450 C. Automated placement equipment at Cincinnati Milacron and NASA Langley was used to fabricate laminates from these experimental ribbons. Ribbons were placed at 405 and 450 C by both sets of equipment. Double cantilever beam and wedge peel tests were used to determine the quality of the laminates and, especially, the interlaminar bond formed during the placement process. Ribbon made under conditions expected to be non-optimal (overheated) resulted in poor placeability and composites with weak interlaminar bond strengths, regardless of placement conditions. Ribbon made under conditions expected to be ideal showed good processability and produced well-consolidated laminates. Results were consistent from machine to machine and demonstrated the importance of ribbon quality in heated-head placement of dry material forms. Preliminary screening criteria for the development and evaluation of ribbon from new matrix materials were validated.

  5. Ribbon Graphs and Mirror Symmetry I

    CERN Document Server

    Sibilla, Nicoló; Zaslow, Eric

    2011-01-01

    Given a ribbon graph $\\Gamma$ with some extra structure, we define, using constructible sheaves, a dg category $CPM(\\Gamma)$ meant to model the Fukaya category of a Riemann surface in the cell of Teichm\\"uller space described by $\\Gamma.$ When $\\Gamma$ is appropriately decorated and admits a combinatorial "torus fibration with section," we construct from $\\Gamma$ a one-dimensional algebraic stack $\\widetilde{X}_\\Gamma$ with toric components. We prove that our model is equivalent to $Perf(\\widetilde{X}_\\Gamma)$, the dg category of perfect complexes on $\\widetilde{X}_\\Gamma$.

  6. Blue Laser.

    Science.gov (United States)

    1985-12-01

    HOLLOW CATHODE LASER FABRICATION 13 4. EXPERIENCE WITH THE BLUE LASER 18 4.1 Operational and Processing Experience 18 4.2 Performance Testing 20 5...34 -. - . •. SECTION 3 BLUE HOLLOW CATHODE LASER FABRICATION This section presents an overview of the steps taken in creating a HCL. There is...to the laser assembly. These steps can actually be considered as the final steps in laser fabrication because some of them involve adding various

  7. Study of growth of single crystal ribbon in space

    Science.gov (United States)

    Wood, V. E.; Markworth, A. J.

    1975-01-01

    The technical feasibility is studied of growing single-crystal silicon ribbon in the space environment. Procedures are described for calculating the electromagnetic fields produced in a silicon ribbon by an rf shaping coil. The forces on the ribbon and the degree of shaping to be expected are determined. The expected steady-state temperature distribution in the ribbon is calculated in the one-dimensional approximation. Calculations on simplified models indicate, that lack of flatness of the shaped ribbon and excessive heating of the melt by the eddy currents induced by the shaping fields may pose problems. An analysis of the relative effects of various kinds of forces other than electromagnetic showed that in the space environment capillarity forces would dominate, and that the shape of the melt is thus principally determined by the shape of any solids with which it comes in contact. This suggests that ribbon may be produced simply by drawing between parallel wires. A concept is developed for a process of off-angle growth, in which the ribbon is pulled at an angle to the solidification front. Such a process promises to offer increased growth rate, better homogeneity, and thinner ribbon.

  8. SOME PECULIARITIES OF DUCTILE SHEAR FAILURE OF AMORPHOUS ALLOY RIBBONS

    NARCIS (Netherlands)

    BENGUS, VZ; TABACHNIKOVA, ED; SHUMILIN, SE; GOLOVIN, YI; MAKAROV, MV; SHIBKOV, AA; MISKUF, J; CSACH, K; Ocelik, Vaclav

    1993-01-01

    The kinetics of a shear crack propagation under ductile shear failure of amorphous alloys ribbons is studied experimentally. Some phenomena that accompany this failure are also studied: repeated alternation of the shear crack orientation, plastic corrugation of a ribbon, extreme local heating at the

  9. Electrostatics-Driven Hierarchical Buckling of Charged Flexible Ribbons

    Science.gov (United States)

    Yao, Zhenwei; Olvera de la Cruz, Monica

    2016-04-01

    We investigate the rich morphologies of an electrically charged flexible ribbon, which is a prototype for many beltlike structures in biology and nanomaterials. Long-range electrostatic repulsion is found to govern the hierarchical buckling of the ribbon from its initially flat shape to its undulated and out-of-plane twisted conformations. In this process, the screening length is the key controlling parameter, suggesting that a convenient way to manipulate the ribbon morphology is simply to change the salt concentration. We find that these shapes originate from the geometric effect of the electrostatic interaction, which fundamentally changes the metric over the ribbon surface. We also identify the basic modes by which the ribbon reshapes itself in order to lower the energy. The geometric effect of the physical interaction revealed in this Letter has implications for the shape design of extensive ribbonlike materials in nano- and biomaterials.

  10. Twisted Ribbons: Theory, Experiment and Applications

    Science.gov (United States)

    Chopin, Julien; Davidovitch, Benjamin; Silva, Flavio A.; Toledo Filho, Romildo D.; Kudrolli, Arshad

    2014-03-01

    We investigate, experimentally and theoretically, the buckling and wrinkling instabilities of a pre-stretched ribbon upon twisting and propose strategies for the fabrication of structured yarns. Our experiment consists in a thin elastic sheet in the form of a ribbon which is initially stretched by a fixed load and then subjected to a twist by rotating the ends through a prescribed angle. We show that a wide variety of shapes and instabilities can be obtained by simply varying the applied twist and tension. The observed structures which include helicoids with and without longitudinal and transverse wrinkles, and spontaneous creases, can be organized in a phase diagram with the tension and twist angle as control parameters [J. Chopin and A. Kudrolli, PRL (2013)]. Using a far-from-threshold analysis and a slender body approximation, we provide a comprehensive understanding of the longitudinal and transverse instabilities and show that several regimes emerge depending on subtle combinations of loading and geometrical parameters. Further, we show that the wrinkling instabilities can be manipulated to fabricate structured yarns which may be used to encapsulate amorphous materials or serve as efficient reinforcements for cement-based composites. COPPETEC / CNPq - Science Without Border Program

  11. Localized modes in nonlinear binary kagome ribbons.

    Science.gov (United States)

    Beličev, P P; Gligorić, G; Radosavljević, A; Maluckov, A; Stepić, M; Vicencio, R A; Johansson, M

    2015-11-01

    The localized mode propagation in binary nonlinear kagome ribbons is investigated with the premise to ensure controlled light propagation through photonic lattice media. Particularity of the linear system characterized by the dispersionless flat band in the spectrum is the opening of new minigaps due to the "binarism." Together with the presence of nonlinearity, this determines the guiding mode types and properties. Nonlinearity destabilizes the staggered rings found to be nondiffracting in the linear system, but can give rise to dynamically stable ringlike solutions of several types: unstaggered rings, low-power staggered rings, hour-glass-like solutions, and vortex rings with high power. The type of solutions, i.e., the energy and angular momentum circulation through the nonlinear lattice, can be controlled by suitable initial excitation of the ribbon. In addition, by controlling the system "binarism" various localized modes can be generated and guided through the system, owing to the opening of the minigaps in the spectrum. All these findings offer diverse technical possibilities, especially with respect to the high-speed optical communications and high-power lasers.

  12. The ribbon continent of northwestern South America

    Science.gov (United States)

    Altamira-Areyan, Armando

    The tectonic structure of the Plate Boundary Zone (PBZ) between the Caribbean Plate (CARIB) and the South American Plate (SOAM) is interpreted using models that require CARIB motion from the Pacific into the Atlantic. Those models can be subdivided into: (1) those in which the island arc rocks that are now in the CARIB-SOAM PBZ have collided with the northern South America margin, either obliquely or directly during the Cretaceous or during the Cenozoic, and (2) those in which the island arc rocks now in the CARIB-SOAM PBZ collided with the west coast of South America during the Cretaceous and were transferred to the northern margin by transform motion during the Cenozoic. Magnetic anomalies were first rotated in the Central and South Atlantic, holding Africa fixed to establish how much NOAM had converged on SOAM during the Cenozoic. WSW convergence was discovered to have been accommodated in the northern boundary of the CARIB. There is no evidence of convergence in the form of Cenozoic island arc igneous rocks on the north coast of South America. Those results are consistent only with models of Class (2) that call for transform movement of material that had collided with the west coast of South America along the CARIB-SOAM PBZ on the northern margin of South America. 40Ar/39Ar ages of island arc rocks from northern Venezuela were found to be older than ca 70 Ma, which is consistent with a requirement of models of Class (2) that those rocks are from an island arc which collided with the west coast of South America during Cretaceous times. Testing that conclusion using data from Ecuador, Colombia, Venezuela, the Netherlands Antilles, Trinidad and Tobago has led to the construction of a new ribbon continent model of the northwestern Cordillera of South America. Because the part of the ribbon continent on the north coast of South America has been experiencing substantial deformation in the Maracaibo block during the past 10 m.y., structures in that body have had to be

  13. Diagrammatic documentation for ribbon computing in Microsoft Office

    Directory of Open Access Journals (Sweden)

    Kaveh Farbeh-Tabrizi

    Full Text Available In 2007 Microsoft changed the graphical user interface of MS Office, and moved away from the long -established drop down menu approach to a ribbon graphical user interface. There have been mixed reactions to Microsoft\\'s ribbon interface. Ericson (2006 mentioned that even the experienced user might have difficulty adopting the interface, and Dostal (2010 concluded that the biggest issue with the Ribbon User Interface is to get accustomed to a redesigned user interface. Reaction to this change was negative among our new and current students. For years the students had tried to memorise how to apply the right commands in Microsoft Office applications by selecting the correct items from the dropdown menus of the WIMP (windows, icons, menus, pointer interface, and now that they were confronted with the new interface their confusion had begun to slow their progress down. The major effect in transition from the traditional WIMP interface to the Ribbon interface had created a difficulty for most students who had their original training with the older versions of MS Office software, as they were not able to locate the commands that they had learnt with the earlier versions of the MS Office in the new Ribbon interfaced version. The shrinking nature of the ribbon that would hide some commands on the ribbon when the resolution of the screen changes was also confusing for those students as they could not quickly locate the command they were looking for because the Ribbon had compacted them to save space. For both new students and also more experienced ones, the approach to learning the Ribbon Interface seemed to be difficult due to the fact that they had to memorise the hierarchy of tab names, group names and then the commands. This led us to enhance our current teaching methods to try to deal with this change.

  14. Nanoscale Morphology in Tensile Fracture of a Brittle Amorphous Ribbon

    Institute of Scientific and Technical Information of China (English)

    Xifeng LI; Kaifeng ZHANG; Guofeng WANG

    2008-01-01

    The paper reports on the observation of nanoscale morphology on the tensile fracture surface of a brittle amorphous Fe-based ribbon. The formation of nanoscale damage cavity structure is a main characteristic morphology on the fracture surfaces. Approaching the ribbon boundary, these damage cavities assemble and form the nanoscale periodic corrugations, which are neither Wallner lines nor crack front waves. The periodic corrugations result from the interactions between the reflected elastic waves by the boundaries of amorphous ribbon and the stress fields of the crack tip.

  15. Transmittance characteristics and tunable sensor performances of plasmonic graphene ribbons

    Science.gov (United States)

    Yan, Xin; Yuan, Lin; Wang, Yueke; Sang, Tian; Yang, Guofeng

    2016-08-01

    We investigate the transmittance characteristics of graphene ribbons numerically. It is found that the transmission dips originate from the transverse and longitudinal resonances of edge graphene plasmon modes, supported by the graphene ribbon resonator. The environmental refractive index changes are detected by measuring the resulting spectral shifts of the resonant transmission dip, so the graphene ribbons can be applied to plasmonic sensor in infrared. Simulation results show that sensing performances for each resonant mode are similar, and figure of merit can be up to 6. Beside, thanks to the tunable permittivity of graphene by bias voltages, the transmittance spectra and sensor performances can be easily tuned.

  16. Nanostructure and magnetic properties of Ni-substituted finemet ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Iturriza, N. [Dpto. Fisica Materiales, Fac. Quimica, UPV/EHU, Apdo. 1072, 20080 San Sebastian (Spain); Fernandez, L. [Dpto. Fisica Materiales, Fac. Quimica, UPV/EHU, Apdo. 1072, 20080 San Sebastian (Spain); Ipatov, M. [Dpto. Fisica Materiales, Fac. Quimica, UPV/EHU, Apdo. 1072, 20080 San Sebastian (Spain); Vara, G. [Dpto. Ingenieria Quimica y Medio Ambiente, EUPSS, YPV/EHU, 20080 San Sebastian (Spain); Pierna, A.R. [Dpto. Ingenieria Quimica y Medio Ambiente, EUPSS, YPV/EHU, 20080 San Sebastian (Spain); Val, J.J. del [Dpto. Fisica Materiales, Fac. Quimica, UPV/EHU, Apdo. 1072, 20080 San Sebastian (Spain) and Unidad de Fisica de Materiales, Centro Mixto CSIC-UPV/EHU, San Sebastian (Spain)]. E-mail: juanjose.delval@ehu.es; Chizhik, A. [Dpto. Fisica Materiales, Fac. Quimica, UPV/EHU, Apdo. 1072, 20080 San Sebastian (Spain); Gonzalez, J. [Dpto. Fisica Materiales, Fac. Quimica, UPV/EHU, Apdo. 1072, 20080 San Sebastian (Spain)

    2007-09-15

    Magnetic anisotropy has been induced during the nanocrystallization process of Ni-rich amorphous ferromagnetic (Finemet) ribbons by means of the application of a constant stress during the annealing process. Magnetization measurements have evidenced the anisotropy of the treated samples. The main goal of this work was the analysis of the treated ribbons using X-ray Diffraction (XRD), Transmission Electronic Microscopy (TEM) and Atomic Force Microscopy (AFM). AFM measurements revealed in all the cases a strong nanocrystallisation of the surface without evidences of amorphous matrix, which contrast with XRD and TEM measurements that have shown a high content of amorphous phase in the bulk of the ribbons. Magneto-optical Kerr effect measurements show much higher coercive field values than in the bulk, indicating a complex magnetic behavior for the surface of the ribbons.

  17. Ribbon electron beam formation by a forevacuum plasma electron source

    Energy Technology Data Exchange (ETDEWEB)

    Klimov, A. S., E-mail: klimov@main.tusur.ru; Burdovitsin, V. A. [Tomsk State University of Control System and Radioelectronics (Russian Federation); Grishkov, A. A. [SB RAS, Institute of High Current Electronics (Russian Federation); Oks, E. M.; Zenin, A. A.; Yushkov, Yu. G. [Tomsk State University of Control System and Radioelectronics (Russian Federation)

    2016-01-15

    Results of the numerical analysis and experimental research on ribbon electron beam generation based on hollow cathode discharge at forevacuum gas pressure are presented. Geometry of the accelerating gap has modified. It lets us focus the ribbon electron beam and to transport it on a distance of several tens of centimeters in the absence of an axial magnetic field. The results of numerical simulations are confirmed by the experiment.

  18. Performance analysis of CO2 laser polished angled ribbon fiber

    Science.gov (United States)

    Sohn, Ik-Bu; Choi, Hun-Kook; Noh, Young-Chul; Lee, Man-Seop; Oh, Jin-Kyoung; Kim, Seong-min; Ahsan, Md. Shamim

    2017-01-01

    This paper demonstrates CO2 laser assisted simultaneous polishing of angled ribbon fibers consisting eight set of optical fibers. The ribbon fibers were rotated vertically at an angle of 12° and polished by repetitive irradiation of CO2 laser beam at the end faces of the fibers. Compared to mechanically polished sharp edged angled fibers, CO2 laser polishing forms curve edged angled fibers. Increase in the curvature of the end faces of the ribbon fibers causes the increase of the fibers' strength, which in turn represents great robustness against fiber connections with other devices. The CO2 laser polished angled fibers have great smoothness throughout the polished area. The smoothness of the fiber end faces have been controlled by varying the number of laser irradiation. After CO2 laser polishing, the average value of the fiber angle of the ribbon fibers is ∼8.28°. The laser polished ribbon fibers show low insertion and return losses when connecting with commercial optical communication devices. The proposed technique of polishing the angled ribbon fibers is highly replicable and reliable and thus suitable for commercial applications.

  19. Distance to the IBEX Ribbon Source Inferred from Parallax

    Science.gov (United States)

    Swaczyna, P.; Bzowski, M.; Christian, E. R.; Funsten, H. O.; McComas, D. J.; Schwadron, N. A.

    2016-06-01

    Maps of energetic neutral atom (ENA) fluxes obtained from observations made by the Interstellar Boundary Explorer (IBEX) revealed a bright structure extending over the sky, subsequently dubbed the IBEX ribbon. The ribbon had not been expected from the existing models and theories prior to IBEX, and a number of mechanisms have since been proposed to explain the observations. In these mechanisms, the observed ENAs emerge from source plasmas located at different distances from the Sun. Since each part of the sky is observed by IBEX twice during the year from opposite sides of the Sun, the apparent position of the ribbon as observed in the sky is shifted due to parallax. To determine the ribbon’s parallax, we found the precise location of the maximum signal of the ribbon observed in each orbital arc. The apparent positions obtained were subsequently corrected for the Compton-Getting effect, gravitational deflection, and radiation pressure. Finally, we selected a part of the ribbon where its position is similar in the different IBEX energy passbands. We compared the apparent positions obtained from the viewing locations on the opposite sides of the Sun, and found that they are shifted by a parallax angle of 0.°41 ± 0.°15, which corresponds to a distance of {140}-38+84 AU. This finding supports models of the ribbon with the source located just outside the heliopause.

  20. Distance to the IBEX Ribbon Source Inferred from Parallax

    CERN Document Server

    Swaczyna, P; Christian, E R; Funsten, H O; McComas, D J; Schwadron, N A

    2016-01-01

    Maps of Energetic Neutral Atom (ENA) fluxes obtained from Interstellar Boundary Explorer (IBEX) observations revealed a bright structure extending over the sky, subsequently dubbed the IBEX ribbon. The ribbon had not been expected from the existing models and theories prior to IBEX, and a number of mechanisms have since been proposed to explain the observations. In these mechanisms, the observed ENAs emerge from source plasmas located at different distances from the Sun. Since each part of the sky is observed by IBEX twice during the year from opposite sides of the Sun, the apparent position of the ribbon as observed in the sky is shifted due to parallax. To determine the ribbon parallax, we found the precise location of the maximum signal of the ribbon observed in each orbital arc. The obtained apparent positions were subsequently corrected for the Compton-Getting effect, gravitational deflection, and radiation pressure. Finally, we selected a part of the ribbon where its position is similar between the IBEX...

  1. Posthuman blues

    CERN Document Server

    Tonnies, Mac

    2013-01-01

    Posthuman Blues, Vol. I is first volume of the edited version of the popular weblog maintained by author Mac Tonnies from 2003 until his tragic death in 2009. Tonnies' blog was a pastiche of his original fiction, reflections on his day-to-day life, trenchant observations of current events, and thoughts on an eclectic range of material he culled from the Internet. What resulted was a remarkably broad portrait of a thoughtful man and the complex times in which he lived, rendered with intellige...

  2. The Local Interstellar Magnetic Field Determined from the IBEX Ribbon

    Science.gov (United States)

    Zirnstein, E.; Funsten, H. O.; Heerikhuisen, J.; Livadiotis, G.; McComas, D. J.; Pogorelov, N. V.

    2015-12-01

    As the solar wind plasma flows away from the Sun, it eventually collides with the local interstellar medium, creating the heliosphere. Neutral atoms from interstellar space travel inside the heliosphere and charge-exchange with the solar wind plasma, creating energetic neutral atoms (ENAs). Some of these ENAs travel outside the heliosphere, undergo two charge-exchange events, and travel back inside the heliosphere towards Earth, with the strongest intensity in directions perpendicular to the interstellar magnetic field (IMF). It is widely believed that this process generates the "ribbon" of enhanced ENA intensity observed by the Interstellar Boundary Explorer (IBEX), and has been shown to explain many key features of the observations. IBEX observations of the ribbon are composed of a complex, line-of-sight integration of ENAs that come from different distances beyond the heliopause, and thus the ENAs detected by IBEX over a wide range of energies are uniquely coupled to the IMF draped around the heliosphere. We present a detailed analysis of the IBEX ribbon measurements using 3D simulations of the heliosphere and computations of the ribbon flux at Earth based on IBEX capabilities, and derive the magnitude and direction of the IMF required to reproduce the position of the IBEX ribbon in the sky. These results have potentially large implications for our understanding of the solar-interstellar environment.

  3. Impulsive Heating of Solar Flare Ribbons Above 10 MK

    CERN Document Server

    Simões, Paulo J A; Fletcher, Lyndsay

    2015-01-01

    The chromospheric response to the input of flare energy is marked by extended extreme ultraviolet (EUV) ribbons and hard X-ray (HXR) footpoints. These are usually explained as the result of heating and bremsstrahlung emission from accelerated electrons colliding in the dense chromospheric plasma. We present evidence of impulsive heating of flare ribbons above 10 MK in a two-ribbon flare. We analyse the impulsive phase of SOL2013-11-09T06:38, a C2.6 class event using data from Atmospheric Imaging Assembly (AIA) on board of Solar Dynamics Observatory (SDO) and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) to derive the temperature, emission measure and differential emission measure of the flaring regions and investigate the evolution of the plasma in the flaring ribbons. The ribbons were visible at all SDO/AIA EUV/UV wavelengths, in particular, at 94 and 131 \\AA\\ filters, sensitive to temperatures of 8 MK and 12 MK. Time evolution of the emission measure of the plasma above 10 MK at the ribb...

  4. Non-Hookean statistical mechanics of clamped graphene ribbons

    Science.gov (United States)

    Bowick, Mark J.; Košmrlj, Andrej; Nelson, David R.; Sknepnek, Rastko

    2017-03-01

    Thermally fluctuating sheets and ribbons provide an intriguing forum in which to investigate strong violations of Hooke's Law: Large distance elastic parameters are in fact not constant but instead depend on the macroscopic dimensions. Inspired by recent experiments on free-standing graphene cantilevers, we combine the statistical mechanics of thin elastic plates and large-scale numerical simulations to investigate the thermal renormalization of the bending rigidity of graphene ribbons clamped at one end. For ribbons of dimensions W ×L (with L ≥W ), the macroscopic bending rigidity κR determined from cantilever deformations is independent of the width when W expected. When W >ℓth , however, this thermally renormalized bending rigidity begins to systematically increase, in agreement with the scaling theory, although in our simulations we were not quite able to reach the system sizes necessary to determine the fully developed power law dependence on W . When the ribbon length L >ℓp , where ℓp is the W -dependent thermally renormalized ribbon persistence length, we observe a scaling collapse and the beginnings of large scale random walk behavior.

  5. From Cylindrical to Stretching Ridges and Wrinkles in Twisted Ribbons

    Science.gov (United States)

    Pham Dinh, Huy; Démery, Vincent; Davidovitch, Benny; Brau, Fabian; Damman, Pascal

    2016-09-01

    Twisted ribbons under tension exhibit a remarkably rich morphology, from smooth and wrinkled helicoids, to cylindrical or faceted patterns. This complexity emanates from the instability of the natural, helicoidal symmetry of the system, which generates both longitudinal and transverse stresses, thereby leading to buckling of the ribbon. Here, we focus on the tessellation patterns made of triangular facets. Our experimental observations are described within an "asymptotic isometry" approach that brings together geometry and elasticity. The geometry consists of parametrized families of surfaces, isometric to the undeformed ribbon in the singular limit of vanishing thickness and tensile load. The energy, whose minimization selects the favored structure among those families, is governed by the tensile work and bending cost of the pattern. This framework describes the coexistence lines in a morphological phase diagram, and determines the domain of existence of faceted structures.

  6. A Magnetic Ribbon Model for Star-Forming Filaments

    CERN Document Server

    Auddy, Sayantan; Kudoh, Takahiro

    2016-01-01

    We develop a magnetic ribbon model for molecular cloud filaments. These result from turbulent compression in a molecular cloud in which the background magnetic field sets a preferred direction. We argue that this is a natural model for filaments and is based on the interplay between turbulence, strong magnetic fields, and gravitationally-driven ambipolar diffusion, rather than pure gravity and thermal pressure. An analytic model for the formation of magnetic ribbons that is based on numerical simulations is used to derive a lateral width of a magnetic ribbon. This differs from the thickness along the magnetic field direction, which is essentially the Jeans scale. We use our model to calculate a synthetic observed relation between apparent width in projection versus observed column density. The relationship is relatively flat, similar to observations, and unlike the simple expectation based on a Jeans length argument.

  7. A Magnetic Ribbon Model for Star-forming Filaments

    Science.gov (United States)

    Auddy, Sayantan; Basu, Shantanu; Kudoh, Takahiro

    2016-11-01

    We develop a magnetic ribbon model for molecular cloud filaments. These result from turbulent compression in a molecular cloud in which the background magnetic field sets a preferred direction. We argue that this is a natural model for filaments and is based on the interplay between turbulence, strong magnetic fields, and gravitationally driven ambipolar diffusion, rather than pure gravity and thermal pressure. An analytic model for the formation of magnetic ribbons that is based on numerical simulations is used to derive a lateral width of a magnetic ribbon. This differs from the thickness along the magnetic field direction, which is essentially the Jeans scale. We use our model to calculate a synthetic observed relation between apparent width in projection versus observed column density. The relationship is relatively flat, similar to observations, and unlike the simple expectation based on a Jeans length argument.

  8. Stability limits for the horizontal ribbon growth of silicon crystals

    Science.gov (United States)

    Daggolu, Parthiv; Yeckel, Andrew; Bleil, Carl E.; Derby, Jeffrey J.

    2013-01-01

    A rigorous, thermal-capillary model, developed to couple heat transfer, melt convection and capillary physics, is employed to assess stability limits of the HRG system for growing silicon ribbons. Extending the prior understanding of this process put forth by Daggolu et al. [Thermal-capillary analysis of the horizontal ribbon growth of silicon crystals, Journal of Crystal Growth 355 (2012) 129-139], model results presented here identify additional failure mechanisms, including the bridging of crystal onto crucible, the spilling of melt from the crucible, and the undercooling of melt at the ribbon tip, that are consistent with prior experimental observations. Changes in pull rate, pull angle, melt height, and other parameters are shown to give rise to limits, indicating that only narrow operating windows exist in multi-dimensional parameter space for stable growth conditions that circumvent these failure mechanisms.

  9. Broadband magnetic losses of nanocrystalline ribbons and powder cores

    Science.gov (United States)

    Beatrice, Cinzia; Dobák, Samuel; Ferrara, Enzo; Fiorillo, Fausto; Ragusa, Carlo; Füzer, Ján; Kollár, Peter

    2016-12-01

    Finemet type alloys have been investigated from DC to 1 GHz at different induction levels upon different treatments: as amorphous precursors, as ribbons nanocrystallized with and without an applied saturating field, as consolidated powders. The lowest energy losses at all frequencies and maximum Snoek's product are exhibited by the transversally field-annealed ribbons. This is understood in terms of rotation-dominated magnetization process in the low-anisotropy material. Intergrain eddy currents are responsible for the fast increase of the losses with frequency and for early permeability relaxation of the powder cores. Evidence for resonant phenomena at high frequencies and for the ensuing inadequate role of the static magnetic constitutive equation of the material in solving the magnetization dynamics via the Maxwell's diffusion equation of the electromagnetic field is provided. It is demonstrated that, by taking the Landau-Lifshitz-Gilbert equation as a constitutive relation, the excellent frequency response of the transverse anisotropy ribbons can be described by analytical method.

  10. Comparison of output power for solar cells with standard and structured ribbons

    Directory of Open Access Journals (Sweden)

    Muehleisen Wolfgang

    2016-01-01

    Full Text Available The optical loss due to the busbar grid and soldered interconnector ribbons on a three busbar standard multicrystalline silicon solar cell’s front side is at 2.3%. One way to reduce this optical loss on cell level and in a photovoltaic (PV module is to use deep structured ribbons as cell connectors. The standard soldered, flat ribbon is replaced with a glued, multiple structured ribbon. The investigation of shiny soldered flat ribbons and multiple structured ribbons in single-cell mini modules demonstrates the light angle dependency and the benefit for the structured alternative. Additional yield measurements for conventional photovoltaic modules with soldered flat and glued multiple structured ribbons technologies were studied under laboratory conditions as well as in outdoor measurements. The simulations and the experimental findings confirmed that the new structured ribbon design increases the short circuit current and the yield by about 2%.

  11. Axonal synapses utilize multiple synaptic ribbons in the mammalian retina.

    Directory of Open Access Journals (Sweden)

    Hong-Lim Kim

    Full Text Available In the mammalian retina, bipolar cells and ganglion cells which stratify in sublamina a of the inner plexiform layer (IPL show OFF responses to light stimuli while those that stratify in sublamina b show ON responses. This functional relationship between anatomy and physiology is a key principle of retinal organization. However, there are at least three types of retinal neurons, including intrinsically photosensitive retinal ganglion cells (ipRGCs and dopaminergic amacrine cells, which violate this principle. These cell types have light-driven ON responses, but their dendrites mainly stratify in sublamina a of the IPL, the OFF sublayer. Recent anatomical studies suggested that certain ON cone bipolar cells make axonal or ectopic synapses as they descend through sublamina a, thus providing ON input to cells which stratify in the OFF sublayer. Using immunoelectron microscopy with 3-dimensional reconstruction, we have identified axonal synapses of ON cone bipolar cells in the rabbit retina. Ten calbindin ON cone bipolar axons made en passant ribbon synapses onto amacrine or ganglion dendrites in sublamina a of the IPL. Compared to the ribbon synapses made by bipolar terminals, these axonal ribbon synapses were characterized by a broad postsynaptic element that appeared as a monad and by the presence of multiple short synaptic ribbons. These findings confirm that certain ON cone bipolar cells can provide ON input to amacrine and ganglion cells whose dendrites stratify in the OFF sublayer via axonal synapses. The monadic synapse with multiple ribbons may be a diagnostic feature of the ON cone bipolar axonal synapse in sublamina a. The presence of multiple ribbons and a broad postsynaptic density suggest these structures may be very efficient synapses. We also identified axonal inputs to ipRGCs with the architecture described above.

  12. Color vision: retinal blues.

    Science.gov (United States)

    Johnston, Jamie; Esposti, Federico; Lagnado, Leon

    2012-08-21

    Two complementary studies have resolved the circuitry underlying green-blue color discrimination in the retina. A blue-sensitive interneuron provides the inhibitory signal required for computing green-blue color opponency.

  13. Generalized trace and modified dimension functions on ribbon categories

    CERN Document Server

    Geer, Nathan; Patureau-Mirand, Bertrand

    2010-01-01

    In this paper we use topological techniques to construct generalized trace and modified dimension functions on ideals in certain ribbon categories. Examples of such ribbon categories naturally arise in representation theory where the usual trace and dimension functions are zero, but these generalized trace and modified dimension functions are non-zero. Such examples include categories of finite dimensional modules of certain Lie algebras and finite groups over a field of positive characteristic and categories of finite dimensional modules of basic Lie superalgebras over the complex numbers. These modified dimensions can be interpreted categorically and are closely related to some basic notions from representation theory.

  14. About graphene ribbons development in laser synthesized nanocarbon

    Science.gov (United States)

    Gavrila Florescu, L.; Vasile, E.; Sandu, I.; Soare, I.; Fleaca, C.; Ianchis, R.; Luculescu, C.; Dutu, E.; Birjega, R.; Morjan, I.; Voicu, I.

    2011-04-01

    The work presents preliminary studies with the goal to extend the share of long graphene ribbons in laser-synthesized carbon black. Investigations revealed the existence, as a major constituent, of graphene ribbons composed of up to 10-15 graphene layers, spaced at ˜0.35-0.37 nm and of tens of nanometres in length. The samples used to study the development of this specific structure were obtained from sensitized acetylene-based mixtures and the experiments were performed following the variation of both the experimental parameters and gas composition.

  15. About graphene ribbons development in laser synthesized nanocarbon

    Energy Technology Data Exchange (ETDEWEB)

    Gavrila Florescu, L. [National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG-36, Bucharest (Romania); Vasile, E. [METAV, 16-18 Zapada Mieilor St., 71529 Bucharest (Romania); Sandu, I.; Soare, I.; Fleaca, C. [National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG-36, Bucharest (Romania); Ianchis, R. [Institute of Chemical Research, 202 Splaiul Independentei, CP 15-159, 76250 Bucharest (Romania); Luculescu, C.; Dutu, E.; Birjega, R.; Morjan, I. [National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG-36, Bucharest (Romania); Voicu, I., E-mail: ionvoicu2001@yahoo.com [National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG-36, Bucharest (Romania)

    2011-04-01

    The work presents preliminary studies with the goal to extend the share of long graphene ribbons in laser-synthesized carbon black. Investigations revealed the existence, as a major constituent, of graphene ribbons composed of up to 10-15 graphene layers, spaced at {approx}0.35-0.37 nm and of tens of nanometres in length. The samples used to study the development of this specific structure were obtained from sensitized acetylene-based mixtures and the experiments were performed following the variation of both the experimental parameters and gas composition.

  16. Full-mesh optical backplane with standard MM fiber ribbons

    Science.gov (United States)

    Ferrario, M.; Coviello, D.; Boffi, P.; Martinelli, M.; Basile, V.; Fassi, I.; Falcucci, M.; Renghini, C.; Scalmati, Paolo

    2016-03-01

    A new optical backplane solution is proposed for high-capacity ICT apparatus. A modular, scalable and full-mesh bandwidth-upgradable optical interconnection between optoelectronic boards is guaranteed thanks to an optimized layout of standard MM 12-fiber ribbons which divides the overall backplane into several independent optical sub-circuits. The novel automated assembly procedure of fiber ribbons inside sub-circuits with a robotic work-cell is described. System validation of the optical backplane performed with commercially available MM 12-fiber transceivers @10Gb/s proved the feasibility of the proposed solution for future optical interconnections with terabit overall capacity.

  17. Optical Möbius strips and twisted ribbon cloaks.

    Science.gov (United States)

    Freund, Isaac

    2014-02-15

    Optical Möbius strips that surround points of circular polarization, C points, in a generic three-dimensional optical field are cloaked by lines of twisted ribbons attached to the C points. When cloaking occurs, the observable signed twist index that counts the number of half-twists (one or three), and also measures the handedness (right or left), of a generic Möbius strip is determined by the twisted ribbon cloaks. Although some cloaks can be detached, they can never all be removed.

  18. Powder and other divided solids mixing. Scale-up and parametric study of a ribbon blender used in pharmaceutical powders mixing.

    Science.gov (United States)

    Côté, Pascal; Abatzoglou, Nicolas

    2006-02-01

    This work is aimed at evaluating the effect of ribbon blender operational parameters on mixture quality. Mix quality parameters and blend uniformity limits are enforced by regulatory bodies. These limits have served in this present work as targets for blending end-points. In a laboratory-scale model ribbon blender, built by scaling down a real industrial unit, powder mixtures composed of white and blue microcrystalline cellulose (MCC) were blended. Blend uniformity was evaluated using a statistical analysis method under various operating conditions such as loading patterns, blender filling percentage, impeller rotational speeds, and mixing times. It was shown that the filling percentage is the most influential mixing parameter. At high impeller rotational speed, the blending end-point was never reached during experimentation.

  19. Instant BlueStacks

    CERN Document Server

    Judge, Gary

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. A fast-paced, example-based approach guide for learning BlueStacks.This book is for anyone with a Mac or PC who wants to run Android apps on their computer. Whether you want to play games that are freely available for Android but not your computer, or you want to try apps before you install them on a physical device or use it as a development tool, this book will show you how. No previous experience is needed as this is written in plain English

  20. Blue ocean leadership.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2014-05-01

    Ten years ago, two INSEAD professors broke ground by introducing "blue ocean strategy," a new model for discovering uncontested markets that are ripe for growth. In this article, they apply their concepts and tools to what is perhaps the greatest challenge of leadership: closing the gulf between the potential and the realized talent and energy of employees. Research indicates that this gulf is vast: According to Gallup, 70% of workers are disengaged from their jobs. If companies could find a way to convert them into engaged employees, the results could be transformative. The trouble is, managers lack a clear understanding of what changes they could make to bring out the best in everyone. Here, Kim and Mauborgne offer a solution to that problem: a systematic approach to uncovering, at each level of the organization, which leadership acts and activities will inspire employees to give their all, and a process for getting managers throughout the company to start doing them. Blue ocean leadership works because the managers' "customers"-that is, the people managers oversee and report to-are involved in identifying what's effective and what isn't. Moreover, the approach doesn't require leaders to alter who they are, just to undertake a different set of tasks. And that kind of change is much easier to implement and track than changes to values and mind-sets.

  1. 75 FR 65465 - Blue Ribbon Commission on America's Nuclear Future, Disposal Subcommittee

    Science.gov (United States)

    2010-10-25

    ... back end of the nuclear fuel cycle. The Commission will provide advice and make recommendations on... nuclear fuel and nuclear waste. The Co-chairs of the Commission requested the formation of the Disposal... beginning at 8 a.m. on November 4, 2010, at the St. Regis Hotel. Registration to speak will close at...

  2. 75 FR 45608 - Blue Ribbon Commission on America's Nuclear Future, Transportation and Storage Subcommittee

    Science.gov (United States)

    2010-08-03

    ... the Act. DATES: Thursday, August 19, 2010, 8:30 a.m.-5 p.m. ADDRESSES: Washington Marriott Hotel, 1221... at approximately 8:30 a.m. at the Washington Marriott Hotel, 1221 22nd Street, NW., Washington, DC....m. on August 19, 2010, at the Washington Marriott Hotel. Those not able to attend the meeting...

  3. Through a glass darkly: reflections on change in health care, nursing, and blue ribbon committees.

    Science.gov (United States)

    O'Neil, Edward H

    2011-06-01

    The confluence of the Future of Nursing report and the calls for comprehensive reform of the health care system in the United States presents a unique opportunity for nursing to redefine its leadership role. This redefinition should be mindful of those places where nursing has and does provide leadership and the unique set of competencies that every nurse possesses that can be focused on leadership work.

  4. Graphene: powder, flakes, ribbons, and sheets.

    Science.gov (United States)

    James, Dustin K; Tour, James M

    2013-10-15

    Graphene's unique physical and electrical properties (high tensile strength, Young's modulus, electron mobility, and thermal conductivity) have led to its nickname of "super carbon." Graphene research involves the study of several different physical forms of the material: powders, flakes, ribbons, and sheets and others not yet named or imagined. Within those forms, graphene can include a single layer, two layers, or ≤10 sheets of sp² carbon atoms. The chemistry and applications available with graphene depend on both the physical form of the graphene and the number of layers in the material. Therefore the available permutations of graphene are numerous, and we will discuss a subset of this work, covering some of our research on the synthesis and use of many of the different physical and layered forms of graphene. Initially, we worked with commercially available graphite, with which we extended diazonium chemistry developed to functionalize single-walled carbon nanotubes to produce graphitic materials. These structures were soluble in common organic solvents and were better dispersed in composites. We developed an improved synthesis of graphene oxide (GO) and explored how the workup protocol for the synthesis of GO can change the electronic structure and chemical functionality of the GO product. We also developed a method to remove graphene layers one-by-one from flakes. These powders and sheets of GO can serve as fluid loss prevention additives in drilling fluids for the oil industry. Graphene nanoribbons (GNRs) combine small width with long length, producing valuable electronic and physical properties. We developed two complementary syntheses of GNRs from multiwalled carbon nanotubes: one simple oxidative method that produces GNRs with some defects and one reductive method that produces GNRs that are less defective and more electrically conductive. These GNRs can be used in low-loss, high permittivity composites, as conductive reinforcement coatings on Kevlar

  5. Triboelectric Nanogenerators for Blue Energy Harvesting.

    Science.gov (United States)

    Khan, Usman; Kim, Sang-Woo

    2016-07-26

    Blue energy in the form of ocean waves offers an enormous energy resource. However, it has yet to be fully exploited in order to make it available for the use of mankind. Blue energy harvesting is a challenging task as the kinetic energy from ocean waves is irregular in amplitude and is at low frequencies. Though electromagnetic generators (EMGs) are well-known for harvesting mechanical kinetic energies, they have a crucial limitation for blue energy conversion. Indeed, the output voltage of EMGs can be impractically low at the low frequencies of ocean waves. In contrast, triboelectric nanogenerators (TENGs) are highly suitable for blue energy harvesting as they can effectively harvest mechanical energies from low frequencies (blue energy harvesting. In this Perspective, we describe some of the recent progress and also address concerns related to durable packaging of TENGs in consideration of harsh marine environments and power management for an efficient power transfer and distribution for commercial applications.

  6. Static and dynamic bifurcations in magnetoelastic ribbons (abstract)

    Science.gov (United States)

    Savage, H. T.; Adler, Charles; Antman, Stuart S.; Melamud, M.

    1987-04-01

    The ΔE effect in certain field annealed amorphous ribbon is now about 10, i.e., Young's modulus E, can be reversibly changed by a factor of 9 with the application of a field of less than 1 Oe. We have reported the field-induced buckling of a vertically oriented ribbon. The ribbon buckles under its own weight due to the reduction of E with field H. Critical buckling values of H were found to be in good agreement with the eigenvalues of the linearized version of the operator describing the process. Here we present: (a) holographic data where the gradient in the fringe spacing obtained from the hologram of the straight and buckled states is a measure of the curvature; and (b) a rigorous mathematical formalism for extracting from experiment the nonlinear constitutive relation between the curvature θ'(s) and the bending couple m(s) where s is the distance along the ribbon. This process must be carried out (with H as a parameter) from H=0, to values of H somewhat above the anisotropy field, to effect a complete description of the magnetoelastic behavior. In dynamic experiments where the ribbon is driven by H=H0+h sin ωt we observe a subharmonic bifurcation (parametric resonance) when ω is about twice the half-wavelength elastic resonance frequency and h exceeds a threshold value governed by the magnitude of ∂E/∂H. Other, more complicated bifurcations are seen as h is increased further. We show the nonlinear equation of motion with damping to explain the bifurcation structure.

  7. TOPICAL REVIEW: New crystalline silicon ribbon materials for photovoltaics

    Science.gov (United States)

    Hahn, G.; Schönecker, A.

    2004-12-01

    The objective of this article is to review, in relation to photovoltaic applications, the current status of crystalline silicon ribbon technologies as an alternative to technologies based on wafers originating from ingots. Increased wafer demand, the foreseeable silicon feedstock shortage, and the need for a substantial module cost reduction are the main issues that must be faced in the booming photovoltaic market. Ribbon technologies make excellent use of silicon, as wafers are crystallized directly from the melt at the desired thickness and no kerf losses occur. Therefore, they offer a high potential for significantly reducing photovoltaic electricity costs as compared to technology based on wafers cut from ingots. However, the defect structure present in the ribbon silicon wafers can limit material quality and cell efficiency. We will review the most successful of the ribbon techniques already used in large scale production or currently in the pilot demonstration phase, with special emphasis on the defects incorporated during crystal growth. Because of the inhomogeneous distribution of defects, mapped characterization techniques have to be applied. Al and P gettering studies give an insight into the complex interaction of defects in the multicrystalline materials as the gettering efficiency is influenced by the state of the chemical bonding of the metal atoms. The most important technique for improvement of carrier lifetimes is hydrogenation, whose kinetics are strongly influenced by oxygen and carbon concentrations present in the material. The best cell efficiencies for laboratory-type (17%-18% cell area: 4 cm2) as well as industrial-type (15%-16% cell area: {\\ge } 80~{\\mathrm {cm^{2}}} ) ribbon silicon solar cells are in the same range as for standard wafers cut from ingots. A substantial cost reduction therefore seems achievable, although the most promising techniques need to be improved.

  8. Dosimetry of wires and single ribbons of Iridium 192; Dosimetria de alambres y ribbons individuales de Iridio-192

    Energy Technology Data Exchange (ETDEWEB)

    Mazzucco, L.D. [Centro Medico Nuclear S.R.L. San Juan (Argentina)

    1998-12-31

    The objective of this work is in order to present in table formats the dosimetry of wires and single ribbons of Iridium with lengths 1-12 cm for each one linear source along the bisector which is perpendicular at tissue sources (water) computed for linear activity 1 mCi/cm in the case of wires, and 1 mCi/seed for ribbons. The above tables are of direct use, adaptable at particular cases so they facilitate logarithmic graphics of doses in function of the distance for interpolation and use in the treatments planning. It was shown that for two sources with identical linear activity and total length, one of the equidistant seeds at 1 cm (ribbon) and one wire on the other hand, the differences in dose rates in near positions can be about the 15% so corroborating that it is not possible to use wire tables for seeds neither vice versa. Moreover it was elaborated tables of practical direct use for dose rate in water at c Gy/hr for wires and Ribbons 1-12 cm length and from 0.5-10 cm of distance in the perpendicular bisector at the Iridium implant. (Author)

  9. Magnetic-Field-Induced Strains of Bonded Ni-Mn-Ga Melt-Spun Ribbons

    Institute of Scientific and Technical Information of China (English)

    QUO Shi-Hai; ZHANG Yang-Huan; LI Jian-Liang; QI Yan; QUAN Bai-Yun; WANG Xin-Lin

    2006-01-01

    Non-stoichiometric Ni50Mn27Ga23 polycrystalline ribbons are prepared by melt-spinning technique. The magnetic-field-induced strain (MFIS) of Ni-Mn-Ga bulk alloy prepared by bonding the melt-spun ribbons is obtained. The experimental results show that Ni50Mn27Ga23 bonded ribbons exhibit a typical thermal-elastic shape memory effect in the thickness direction. The martensitic transformation strain of bonded ribbons is an expansive strain of about 0.3% without the magnetic fieid and a contractive strain of about -0.46% at the magnetic field of 1T. The field can not only enhance the value of the martensitic transformation strain of the bonded ribbons, but can also change the direction of the strain. The bonded ribbons alloy presents negative MFIS and obtains a larger value of the strain though influenced by the adhesive between the ribbons. Therefore, the preparation technique of the Ni-Mn-Ga bulk alloy by bonding melt-spun ribbons is helpful to get rid of the size restriction of the ribbon and to broaden the applications of the ribbons.

  10. Relating structure and function of inner hair cell ribbon synapses.

    Science.gov (United States)

    Wichmann, C; Moser, T

    2015-07-01

    In the mammalian cochlea, sound is encoded at synapses between inner hair cells (IHCs) and type I spiral ganglion neurons (SGNs). Each SGN receives input from a single IHC ribbon-type active zone (AZ) and yet SGNs indefatigably spike up to hundreds of Hz to encode acoustic stimuli with submillisecond precision. Accumulating evidence indicates a highly specialized molecular composition and structure of the presynapse, adapted to suit these high functional demands. However, we are only beginning to understand key features such as stimulus-secretion coupling, exocytosis mechanisms, exo-endocytosis coupling, modes of endocytosis and vesicle reformation, as well as replenishment of the readily releasable pool. Relating structure and function has become an important avenue in addressing these points and has been applied to normal and genetically manipulated hair cell synapses. Here, we review some of the exciting new insights gained from recent studies of the molecular anatomy and physiology of IHC ribbon synapses.

  11. Terahertz wavefront control by tunable metasurface made of graphene ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Yatooshi, Takumi; Ishikawa, Atsushi, E-mail: a-ishikawa@okayama-u.ac.jp; Tsuruta, Kenji [Department of Electrical and Electronic Engineering, Okayama University, 3-1-1 Tsushimanaka, Kitaku, Okayama 700-8530 (Japan)

    2015-08-03

    We propose a tunable metasurface consisting of an array of graphene ribbons on a silver mirror with a SiO{sub 2} gap layer to control reflected wavefront at terahertz frequencies. The graphene ribbons exhibit localized plasmon resonances depending on their Fermi levels to introduce abrupt phase shifts along the metasurface. With interference of the Fabry-Perot resonances in the SiO{sub 2} layer, phase shift through the system is largely accumulated, covering the 0-to-2π range for full control of the wavefront. Numerical simulations prove that wide-angle beam steering up to 53° with a high reflection efficiency of 60% is achieved at 5 THz within a switching time shorter than 0.6 ps.

  12. Blue cures blue but be cautious

    Directory of Open Access Journals (Sweden)

    Pranav Sikka

    2011-01-01

    Full Text Available Methemoglobinemia is a disorder characterized by the presence of >1% methemoglobin (metHb in the blood. Spontaneous formation of methemoglobin is normally counteracted by protective enzyme systems, for example, nicotinamide adenine dinucleotide phosphate (NADPH methemoglobin reductase. Methemoglobinemia is treated with supplemental oxygen and methylene blue (1-2 mg/kg administered slow intravenously, which acts by providing an artificial electron acceptor for NADPH methemoglobin reductase. But known or suspected glucose-6-phosphate dehydrogenase (G6PD deficiency is a relative contraindication to the use of methylene blue because G6PD is the key enzyme in the formation of NADPH through pentose phosphate pathway and G6PD-deficient individuals generate insufficient NADPH to efficiently reduce methylene blue to leukomethylene blue, which is necessary for the activation of the NADPH-dependent methemoglobin reductase system. So, we should be careful using methylene blue in methemoglobinemia patient before G6PD levels.

  13. The hydrodynamics of ribbon-fin propulsion during impulsive motion.

    Science.gov (United States)

    Shirgaonkar, Anup A; Curet, Oscar M; Patankar, Neelesh A; Maciver, Malcolm A

    2008-11-01

    Weakly electric fish are extraordinarily maneuverable swimmers, able to swim as easily forward as backward and rapidly switch swim direction, among other maneuvers. The primary propulsor of gymnotid electric fish is an elongated ribbon-like anal fin. To understand the mechanical basis of their maneuverability, we examine the hydrodynamics of a non-translating ribbon fin in stationary water using computational fluid dynamics and digital particle image velocimetry (DPIV) of the flow fields around a robotic ribbon fin. Computed forces are compared with drag measurements from towing a cast of the fish and with thrust estimates for measured swim-direction reversals. We idealize the movement of the fin as a traveling sinusoidal wave, and derive scaling relationships for how thrust varies with the wavelength, frequency, amplitude of the traveling wave and fin height. We compare these scaling relationships with prior theoretical work. The primary mechanism of thrust production is the generation of a streamwise central jet and the associated attached vortex rings. Under certain traveling wave regimes, the ribbon fin also generates a heave force, which pushes the body up in the body-fixed frame. In one such regime, we show that as the number of waves along the fin decreases to approximately two-thirds, the heave force surpasses the surge force. This switch from undulatory parallel thrust to oscillatory normal thrust may be important in understanding how the orientation of median fins may vary with fin length and number of waves along them. Our results will be useful for understanding the neural basis of control in the weakly electric knifefish as well as for engineering bio-inspired vehicles with undulatory thrusters.

  14. Explosive Chromospheric Evaporation in a Circular-ribbon Flare

    CERN Document Server

    Zhang, Q M; Ning, Z J; Su, Y N; Ji, H S; Guo, Y

    2016-01-01

    In this paper, we report our multiwavelength observations of the C4.2 circular-ribbon flare in active region (AR) 12434 on 2015 October 16. The short-lived flare was associated with positive magnetic polarities and a negative polarity inside, as revealed by the photospheric line-of-sight magnetograms. Such magnetic pattern is strongly indicative of a magnetic null point and spine-fan configuration in the corona. The flare was triggered by the eruption of a mini-filament residing in the AR, which produced the inner flare ribbon (IFR) and the southern part of a closed circular flare ribbon (CFR). When the eruptive filament reached the null point, it triggered null point magnetic reconnection with the ambient open field and generated the bright CFR and a blowout jet. Raster observations of the \\textit{Interface Region Imaging Spectrograph} (\\textit{IRIS}) show plasma upflow at speed of 35$-$120 km s$^{-1}$ in the Fe {\\sc xxi} 1354.09 {\\AA} line ($\\log T\\approx7.05$) and downflow at speed of 10$-$60 km s$^{-1}$ i...

  15. Magnetoimpedance of cobalt-based amorphous ribbons/polymer composites

    Science.gov (United States)

    Semirov, A. V.; Derevyanko, M. S.; Bukreev, D. A.; Moiseev, A. A.; Kudryavtsev, V. O.; Safronov, A. P.

    2016-10-01

    The combined influence of the temperature, the elastic tensile stress and the external magnetic field on the total impedance and impedance components were studied for rapidly quenched amorphous Co75Fe5Si4B16 ribbons. Both as-cast amorphous ribbons and Co75Fe5Si4B16/polymer amorphous ribbon based composites were considered. Following polymer coverings were studied: modified rubber solution in o-xylene, solution of butyl methacrylate and methacrylic acid copolymer in isopropanol and solution of polymethylphenylsiloxane resin in toluene. All selected composites showed very good adhesion of the coverings and allowed to provide temperature measurements from 163 K up to 383 K under the applied deforming tensile force up to 30 N. The dependence of the modulus of the impedance and its components on the external magnetic field was influenced by the elastic tensile stresses and was affected by the temperature of the samples. It was shown that maximal sensitivity of the impedance and its components to the external magnetic field was observed at minimal temperature and maximal deforming force depended on the frequency of an alternating current.

  16. Graphene-ribbon-coupled tunable enhanced transmission through metallic grating

    Science.gov (United States)

    Peng, Yu-Xiang; He, Meng-Dong; Li, Ze-Jun; Wang, Kai-Jun; Li, Shui; Li, Jian-Bo; Liu, Jian-Qiang; Long, Mengqiu; Hu, Wei-Da; Chen, Xiaoshuang

    2017-01-01

    We report the tunable enhanced transmission of light through a hybrid metal-graphene structure, in which a graphene ribbon array is situated over a metallic grating. The graphene ribbon is employed to make the graphene-insulator-metal waveguide of finite length as a Fabry-Perot (F-P) cavity. When the slit of metallic grating is opened at the position with a maximal magnetic field in F-P resonant cavity, the transmission of light through metallic grating is greatly enhanced since the strongly localized magnetic field is effectively coupled to the slit. The transmission spectrum and the enhancement factor can be adjusted by changing geometrical parameters including the width and the length of slit, the width of graphene ribbon and the period of metallic grating. The transmission peaks exhibit a broad tuning range with a small change in the Fermi energy level of graphene. Moreover, the enhancement factor of transmission peak can be manipulated by the Fermi energy level and the carrier mobility of graphene, and an enhancement factor of 154 is obtained. The findings expand our understanding of hybrid metal-graphene plasmons and have potential applications in building active plasmonic devices.

  17. Is Borg’s perceived exertion scale a useful indicator of muscular and cardiovascular load in blue-collar workers with lifting tasks? A cross-sectional workplace study

    OpenAIRE

    2013-01-01

    Purpose To investigate associations between perceived exertion and objectively assessed muscular and cardiovascular load during a full working day among workers with manual lifting tasks. Methods A total of 159 men and 41 women from 14 workplaces with manual lifting tasks participated. Participants reported perceived exertion (BORG-CR10) at midday and after work. Surface electromyography of the thigh, lower back and neck muscles were normalized to isometric voluntary contractions (MVC) to exp...

  18. Synaptic Ribbons Require Ribeye for Electron Density, Proper Synaptic Localization, and Recruitment of Calcium Channels

    Directory of Open Access Journals (Sweden)

    Caixia Lv

    2016-06-01

    Full Text Available Synaptic ribbons are structures made largely of the protein Ribeye that hold synaptic vesicles near release sites in non-spiking cells in some sensory systems. Here, we introduce frameshift mutations in the two zebrafish genes encoding for Ribeye and thus remove Ribeye protein from neuromast hair cells. Despite Ribeye depletion, vesicles collect around ribbon-like structures that lack electron density, which we term “ghost ribbons.” Ghost ribbons are smaller in size but possess a similar number of smaller vesicles and are poorly localized to synapses and calcium channels. These hair cells exhibit enhanced exocytosis, as measured by capacitance, and recordings from afferent neurons post-synaptic to hair cells show no significant difference in spike rates. Our results suggest that Ribeye makes up most of the synaptic ribbon density in neuromast hair cells and is necessary for proper localization of calcium channels and synaptic ribbons.

  19. In-plane magnetic anisotropy along the width in amorphous magnetic ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Tejedor, M.; Garcia, J.A.; Carrizo, J.; Elbaile, L. E-mail: elbaile@pinon.ccu.uniovi.es; Santos, J.D.; Mira, J.; Rivas, J

    2004-05-01

    A study about the variation of the in-plane magnetic anisotropy along the width of the ribbon is carried out in Co- and Fe-based amorphous magnetic ribbons. From the measurements of the anisotropy in as-quenched, mechanical polished and annealed samples the origin of the lack of homogeneity of the in-plane magnetic anisotropy in wide amorphous ribbons is determined. In addition a shape magnetic anisotropy that we think is originated by the edge effect was found.

  20. Alteration of in vivo cellulose ribbon assembly by carboxymethylcellulose and other cellulose derivatives

    OpenAIRE

    1982-01-01

    In vivo cellulose ribbon assembly by the Gram-negative bacterium Acetobacter xylinum can be altered by incubation in carboxymethylcellulose (CMC), a negatively charged water-soluble cellulose derivative, and also by incubation in a variety of neutral, water-soluble cellulose derivatives. In the presence of all of these substituted celluloses, normal fasciation of microfibril bundles to form the typical twisting ribbon is prevented. Alteration of ribbon assembly is most extensive in the presen...

  1. Growth of silicon ribbon by edge-defined, film-fed growth

    Science.gov (United States)

    Bates, H. E.; Jewett, D. N.; White, V. E.

    1974-01-01

    Recent advances in the application of the edge-defined, film-fed growth (EFG) method to silicon ribbon are described. Ribbons up to 2 x 40 cm and 1 x 70 cm in width and length, respectively, have been grown at rates of 1 to 2.5 cm/min. The electrical properties of typical undoped ribbons are resistivity of 0.5 to 5 ohm-cm p-type, and hole mobility of 200 to 350 sq cm/V-sec. Ribbon growth speeds are consistent with the use of EFG silicon for terrestrial power.

  2. The mechanics of Ribbons and Möbius bands

    CERN Document Server

    Fried, Eliot

    2016-01-01

    Recent developments in biology and nanotechnology have stimulated a rapidly growing interest in the mechanics of thin, flexible ribbons and Mobius bands. This edited volume contains English translations of four seminal papers on this topic, all originally written in German; of these, Michael A. Sadowsky published the first in 1929, followed by two others in 1930, and Walter Wunderlich published the last in 1962. The volume also contains invited, peer-reviewed, original research articles on related topics. Previously published in the Journal of Elasticity, Volume 119, Issue 1-2, 2015.

  3. The growth of lithium niobate ribbons using Stepanov's method

    Science.gov (United States)

    Redkin, B. S.; Satunkin, G. A.; Tatarchenko, V. A.; Umarov, L. M.; Gubina, L. I.

    1983-02-01

    Lithium niobate crystals were grown by Stepanov's method in induction furnaces using capillary feeding from platinum crucibles 50 mm in diameter and 50 mm high. Ribbons having the dimensions 20x50x2 mm and 12x70x2 mm were obtained at a rate of 0.1-0.5 mm/min, with the pulling axis corresponding to the 0001 direction. It is shown that the shape of the solidification front and the quality of the grown crystals are determined to a large extent by the type of the shaping device used (monocapillary or multicapillary).

  4. Klein tunneling through an oblique barrier in graphene ribbons

    CERN Document Server

    Oh, J H

    2010-01-01

    We study a transmission coefficient of graphene nanoribbons with a top gate which acts as an oblique barrier. Using a Green function method based on the Dirac-like equation, scattering among transverse modes due to the oblique barrier is taken into account numerically. In contrast to the 2-dimensional graphene sheet, we find that the pattern of transmission in graphene ribbons depends strongly on the electronic structure in the region of the barrier. Consequently, irregular structures in the transmission coefficient are predicted while perfect transmission is still calculated in the case of metallic graphene independently of angle and length of the oblique barrier.

  5. Magnetoband structures of AB-stacked zigzag nanographite ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.P.; Chiu, C.W.; Shyu, F.L.; Chen, R.B.; Lin, M.F

    2002-12-30

    Magnetoband structures of AB-stacked zigzag nanographite ribbons are studied by the tight-binding model. The magnetic field changes band width, energy space, and energy dispersions (the produce of Landau subbands and Landau levels). It causes many zero energy points. Such points and corresponding localized states are studied in detail. There are certain important differences between localized states and edge states. Oscillation period of Landau subbands are determined by these points. The interribbon interactions also affect magnetoband structures, such as energy dispersions, band width, oscillation period of Landau subbands, and flux dependence of Hofstadter butterflies.

  6. Nanoscale phase change memory with graphene ribbon electrodes

    Science.gov (United States)

    Behnam, Ashkan; Xiong, Feng; Cappelli, Andrea; Wang, Ning C.; Carrion, Enrique A.; Hong, Sungduk; Dai, Yuan; Lyons, Austin S.; Chow, Edmond K.; Piccinini, Enrico; Jacoboni, Carlo; Pop, Eric

    2015-09-01

    Phase change memory (PCM) devices are known to reduce in power consumption as the bit volume and contact area of their electrodes are scaled down. Here, we demonstrate two types of low-power PCM devices with lateral graphene ribbon electrodes: one in which the graphene is patterned into narrow nanoribbons and the other where the phase change material is patterned into nanoribbons. The sharp graphene "edge" contacts enable switching with threshold voltages as low as ˜3 V, low programming currents (100. Large-scale fabrication with graphene grown by chemical vapor deposition also enables the study of heterogeneous integration and that of variability for such nanomaterials and devices.

  7. Mammalian Cochlear Hair Cell Regeneration and Ribbon Synapse Reformation

    Directory of Open Access Journals (Sweden)

    Xiaoling Lu

    2016-01-01

    Full Text Available Hair cells (HCs are the sensory preceptor cells in the inner ear, which play an important role in hearing and balance. The HCs of organ of Corti are susceptible to noise, ototoxic drugs, and infections, thus resulting in permanent hearing loss. Recent approaches of HCs regeneration provide new directions for finding the treatment of sensor neural deafness. To have normal hearing function, the regenerated HCs must be reinnervated by nerve fibers and reform ribbon synapse with the dendrite of spiral ganglion neuron through nerve regeneration. In this review, we discuss the research progress in HC regeneration, the synaptic plasticity, and the reinnervation of new regenerated HCs in mammalian inner ear.

  8. Transmittance characteristics of plasmonic graphene ribbons with a wing

    Science.gov (United States)

    Yuan, Lin; Yan, Xin; Wang, Yueke; Sang, Tian; Yang, Guofeng

    2016-09-01

    We numerically investigate the transmittance characteristics of graphene ribbons with a wing by the finite element method. By determining the dispersion relation of edge graphene plasmon (EGP) modes and analyzing the mode distributions, it is considered that the transmission dips originate from the resonances of three EGP modes, namely, the symmetrical EGPs, antisymmetrical EGPs, and EGPs of a semi-infinite sheet. By changing the width and length of the wing, it was further confirmed that transmission dips originate from the EGP modes. Owing to the tunable permittivity of graphene by adjusting the gate voltage, the transmittance dips can be easily tuned.

  9. Blue and White Pot

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    Many recent archaeological studies have proven that the earliest blue and white porcelain was produced from the kiln in Gongxian County, Henan Province in the Tang Dynasty (618-907). It was an important variety of porcelain available for export then. The early blue and white porcelain in the Yuan Dynasty appeared dark and gray. During the reign of Zhizheng, clear blue and white porcelain was produced, indicating

  10. Cellular blue naevus

    Directory of Open Access Journals (Sweden)

    Mittal R

    2001-01-01

    Full Text Available A 31-year-old man had asymptomatic, stationary, 1.5X2 cm, shiny, smooth, dark blue nodule on dorsum of right hand since 12-14 years. In addition he had developed extensive eruption of yellow to orange papulonodular lesions on extensors of limbs and buttocks since one and half months. Investigations confirmed that yellow papules were xanthomatosis and he had associated diabetes mellitus and hyperlipidaemia. Biopsy of blue nodule confirmed the clinical diagnosis of cellular blue naevus. Cellular blue naevus is rare and its association with xanthomatosis and diabetes mellitus were interesting features of above patients which is being reported for its rarity.

  11. Research on PCC Control Method for Ribbon-free Random Winding

    Institute of Scientific and Technical Information of China (English)

    WEI Jian; WANG Ming-hong; TANG Yi-fan; LU Wen-hua; WU Wen-ying

    2004-01-01

    Based on analyzing the overlap appearance of random winding, basic principles of ribbon-free random winding and parametric selections for anti-overlap are discussed. The ribbon-free random winding control system and its related hardware construction as well as its software design are introduced by applying PCC technology to high speed spinning machine of synthetic filament.

  12. Magnetic properties of Sm5Fe17 melt-spun ribbons and their borides

    Directory of Open Access Journals (Sweden)

    Tetsuji Saito

    2015-10-01

    Full Text Available Sm5Fe17 melt-spun ribbons exhibited low coercivity and partly or mostly consisted of the amorphous phase. Annealing of Sm5Fe17 melt-spun ribbon resulted in the formation of the Sm5Fe17 phase. The annealed Sm5Fe17 melt-spun ribbon exhibited a high coercivity. It was found that the addition of B to the Sm5Fe17 alloy resulted in the promotion of the Sm2Fe14B phase. Annealed Sm5Fe17Bx (x = 0.5 melt-spun ribbons consisted of the Sm5Fe17 phase together with the Sm2Fe14B and SmFe2 phases. On the other hand, annealed Sm5Fe17Bx (x = 1.0-1.5 melt-spun ribbons consisted of the Sm2Fe14B and SmFe2 phases without the Sm5Fe17 phase. The resultant Sm5Fe17Bx (x = 1.0-1.5 melt-spun ribbons still showed a coercivity of around 2 kOe. The annealed Sm5Fe17 melt-spun ribbon exhibited a high coercivity over 25 kOe and a remanence of 40 emu/g, whereas the annealed Sm5Fe17B1.0 melt-spun ribbon exhibited a high remanence of 65 emu/g and a coercivity of 2.0 kOe.

  13. Fluid-Structure Interaction Study on a Pre-Buckled Deformable Flat Ribbon

    Science.gov (United States)

    Fovargue, Lauren; Shams, Ehsan; Watterson, Amy; Corson, Dave; Filardo, Benjamin; Zimmerman, Daniel; Shan, Bob; Oberai, Assad

    2015-11-01

    A Fluid-Structure Interaction study is conducted for the flow over a deformable flat ribbon. This mechanism, which is called ribbon frond, maybe used as a device for pumping water and/or harvesting energy in rivers. We use a lower dimensional mathematical model, which represents the ribbon as a pre-buckled structure. The surface forces from the fluid flow, dictate the deformation of the ribbon, and the ribbon in turn imposes boundary conditions for the incompressible Navier-Stokes equations. The mesh motion is handled using an Arbitrary Lagrangian-Eulerian (ALE) scheme and the fluid-structure coupling is handled by iterating over the staggered governing equations for the structure, the fluid and the mesh. Simulations are conducted at three different free stream velocities. The results, including the frequency of oscillations, show agreement with experimental data. The vortical structures near the surface of the ribbon and its deformation are highly correlated. It is observed that the ribbon motion exhibits deviation from a harmonic motion, especially at lower free stream velocities. The behavior of the ribbon is compared to swimming animals, such as eels, in order to better understand its performance. The authors acknowledge support from ONR SBIR Phase II, contract No. N0001412C0604 and USDA, NIFA SBIR Phase I, contract No. 2013-33610-20836 and NYSERDA PON 2569, contract No. 30364.

  14. On the temperature dependent magnetic properties of as-spun Mn-Bi ribbons

    Science.gov (United States)

    Kavita, S.; Seelam, U. M. R.; Prabhu, D.; Gopalan, R.

    2015-03-01

    The structural and magnetic properties of melt-spun ribbons with nominal composition of Mn55Bi45 were investigated using X-ray diffraction, transmission electron microscopy and magnetometer measurements. A large coercivity (Hc) of 0.8 T was observed in the as-spun ribbons. Microstructure reveals the presence of Mn-Bi nanoparticles in the as-spun ribbons. Coercivity was found to increase with increasing temperature with a maximum coercivity of 1.4 T at T=503 K in the as-spun ribbons. Heat treatment of the as-spun ribbons resulted in the increase of LTP MnBi phase. Spin reorientation transition (TSR) was observed around 100 K.

  15. On the temperature dependent magnetic properties of as-spun Mn–Bi ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Kavita, S., E-mail: srikanti.kavita@gmail.com [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Chennai 600113 (India); Seelam, U.M.R. [National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Prabhu, D.; Gopalan, R. [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Chennai 600113 (India)

    2015-03-01

    The structural and magnetic properties of melt-spun ribbons with nominal composition of Mn{sub 55}Bi{sub 45} were investigated using X-ray diffraction, transmission electron microscopy and magnetometer measurements. A large coercivity (H{sub c}) of 0.8 T was observed in the as-spun ribbons. Microstructure reveals the presence of Mn–Bi nanoparticles in the as-spun ribbons. Coercivity was found to increase with increasing temperature with a maximum coercivity of 1.4 T at T=503 K in the as-spun ribbons. Heat treatment of the as-spun ribbons resulted in the increase of LTP MnBi phase. Spin reorientation transition (T{sub SR}) was observed around 100 K. - Highlights: • Mn–Bi system by melt spinning • Coercivity increases with temperature • The LTP phase increases with heat treatment.

  16. Ribbon Ion Beam with Controlled Directionality and Local Reactive Chemistry

    Science.gov (United States)

    Biloiu, Costel; Gilchrist, Glen; Kontos, Alex; Basame, Solomon; Rockwell, Tyler; Campbell, Chris; Daniels, Kevin; Allen, Ernest; Wallace, Jay; Ballou, Jon; Hertel, Richard; Chen, Tsung-Liang; Liang, Shurong; Singh, Vikram

    2016-09-01

    A plasma processing technology designed for etch of 3D semiconductor structures is presented. The technology is characterized by controllable ion directionality and local reactive chemistry and it is based on proprietary Applied Materials - Varian Semiconductor Equipment ribbon ion beam architecture. It uses a combination of inert gas ion beam and injection of reactive chemical species at the Point-of-Use (PoU), i.e., at the wafer surface. The ion source uses an inductively coupled plasma source and a diode-type extraction optics. A beam shaping electrode allows extraction of two symmetrical ribbon-like beamlets. The ion beam has in situ controllable ion angular distribution in both mean angle and angular spread. The beam has a uniform distribution of beam current and angles over a waist exceeding 300 mm, allowing full wafer processing in one pass. Chemical compounds are delivered at PoU through linear shower heads. The reactive chemical compound delivered in this fashion maintains its molecular integrity. This result in protection of the trench side walls from deposition of etch residue and facilitates formation of volatile byproducts. The technology was used successfully for mitigation of Magnetic Tunel Junction etch residue. Other applications were this technology differentiate from present technologies are contact liner etch, Co recess, and 1D hole elongation.

  17. GPU-accelerated visualization of protein dynamics in ribbon mode

    Science.gov (United States)

    Wahle, Manuel; Birmanns, Stefan

    2011-01-01

    Proteins are biomolecules present in living organisms and essential for carrying out vital functions. Inherent to their functioning is folding into different spatial conformations, and to understand these processes, it is crucial to visually explore the structural changes. In recent years, significant advancements in experimental techniques and novel algorithms for post-processing of protein data have routinely revealed static and dynamic structures of increasing sizes. In turn, interactive visualization of the systems and their transitions became more challenging. Therefore, much research for the efficient display of protein dynamics has been done, with the focus being space filling models, but for the important class of abstract ribbon or cartoon representations, there exist only few methods for an efficient rendering. Yet, these models are of high interest to scientists, as they provide a compact and concise description of the structure elements along the protein main chain. In this work, a method was developed to speed up ribbon and cartoon visualizations. Separating two phases in the calculation of geometry allows to offload computational work from the CPU to the GPU. The first phase consists of computing a smooth curve along the protein's main chain on the CPU. In the second phase, conducted independently by the GPU, vertices along that curve are moved to set up the final geometrical representation of the molecule.

  18. Hooked flare ribbons and flux-rope related QSL footprints

    CERN Document Server

    Zhao, Jie; Aulanier, Guillaume; Schmieder, Brigitte; Pariat, Etienne; Li, Hui

    2016-01-01

    We studied the magnetic topology of active region 12158 on 2014 September 10 and compared it with the observations before and early in the flare which begins at 17:21 UT (SOL2014-09-10T17:45:00). Our results show that the sigmoidal structure and flare ribbons of this active region observed by SDO/AIA can be well reproduced from a Grad-Rubin non linear force free field extrapolation method. Various inverse-S and -J shaped magnetic field lines, that surround a coronal flux rope, coincide with the sigmoid as observed in different extreme ultraviolet wavelengths, including its multi-threaded curved ends. Also, the observed distribution of surface currents in the magnetic polarity where it was not prescribed is well reproduced. This validates our numerical implementation and set-up of the Grad-Rubin method. The modeled double inverse-J shaped Quasi-Separatrix Layer (QSL) footprints match the observed flare ribbons during the rising phase of the flare, including their hooked parts. The spiral-like shape of the latt...

  19. Feeling blue? Blue phosphors for OLEDs

    Directory of Open Access Journals (Sweden)

    Hungshin Fu

    2011-10-01

    Full Text Available Research on organic light emitting diodes (OLEDs has been revitalized, partly due to the debut of the OLED TV by SONY in 2008. While there is still plenty of room for improvement in efficiency, cost-effectiveness and longevity, it is timely to report on the advances of light emitting materials, the core of OLEDs, and their future perspectives. The focus of this account is primarily to chronicle the blue phosphors developed in our laboratory. Special attention is paid to the design strategy, synthetic novelty, and their OLED performance. The report also underscores the importance of the interplay between chemistry and photophysics en route to true-blue phosphors.

  20. 75 FR 41804 - Notice of Final Determination of Sales at Less Than Fair Value: Narrow Woven Ribbons with Woven...

    Science.gov (United States)

    2010-07-19

    .... Narrow woven ribbons subject to the investigation may: also include natural or other non-man-made fibers... containing non-subject merchandise; (11) narrow woven ribbon that is (a) affixed to non-subject merchandise as a working component of such ] non-subject merchandise, such as where narrow woven ribbon...

  1. 75 FR 56982 - Narrow Woven Ribbons With Woven Selvedge From Taiwan and the People's Republic of China: Amended...

    Science.gov (United States)

    2010-09-17

    ...) Narrow woven ribbon affixed (including by tying) as a decorative detail to non-subject merchandise, such... decorative detail to packaging containing non-subject merchandise; (11) Narrow woven ribbon that is (a... International Trade Administration Narrow Woven Ribbons With Woven Selvedge From Taiwan and the...

  2. Separation of the IBEX Ribbon from the Globally Distributed Energetic Neutral Atom Flux

    Science.gov (United States)

    Schwadron, N. A.; Allegrini, F.; Bzowski, M.; Christian, E. R.; Crew, G. B.; Dayeh, M. A.; Demajistre, R.; Frisch, P. C.; Funsten, H. O.; Fuselier, S. A.; Goodrich, K. A.; Gruntman, M.; Janzen, P. H.; Kucharek, H.; Livadiotis, G.; McComas, D. J.; Moebius, E.; Prested, C. L.; Reisenfeld, D. B.; Reno, M. L.; Roelof, E. C.; Siegel, J. E.

    2010-12-01

    The Interstellar Boundary Explorer (IBEX) Mission observes a remarkable feature, the IBEX ribbon. This very narrow ~20° wide feature has energetic neutral atom (ENA) flux ~2-3 times the ENA flux that is globally distributed over other portions of the IBEX maps. Here, we separate ENA emissions in the ribbon from the globally distributed flux by applying a mask over the ribbon and regions where ENAs are produced from sources other than the heliosphere. We then solve for the globally distributed flux using two distinct methods: (1) an interpolation scheme and (2) a decomposition based on real-valued spherical harmonics. Our analysis shows that the energy spectrum and the spatial distribution of the ribbon are distinct from the surrounding globally distributed flux. The ribbon energy spectrum exhibits a knee between ~1 and 4 keV, and the angular distribution transverse to the ribbon is approximately independent of energy. In contrast, the globally distributed flux does not show a clear knee, and more closely conforms to a power-law over much of the sky. The slope of the power-law steepens from the nose to tail, suggesting a weaker termination shock toward the tail as compared to the nose. Both the slope in the energy distribution of the globally distributed flux and the knee in the energy distribution of the ribbon are ordered by latitude. Thus, we develop several methods to separate the ribbon from the globally distributed ENA flux in the maps observed by IBEX. Our analysis shows that the IBEX ribbon is distinct not only in its spatial distribution, but also its energy distribution, which suggests that the source plasma populations of the ribbon and globally distributed flux are produced via a distinct physical process.

  3. Blue Ocean Thinking

    Science.gov (United States)

    Orem, Donna

    2016-01-01

    This article describes a concept called the "blue ocean thinking strategy," developed by W. Chan Kim and Renée Mauborgne, professors at INSEAD, an international graduate school of business in France. The "blue ocean" thinking strategy considers opportunities to create new markets for services, rather than focusing solely on…

  4. Blue Willow Story Plates

    Science.gov (United States)

    Fontes, Kris

    2009-01-01

    In the December 1997 issue of "SchoolArts" is a lesson titled "Blue Willow Story Plates" by Susan Striker. In this article, the author shares how she used this lesson with her middle-school students many times over the years. Here, she describes a Blue Willow plate painting project that her students made.

  5. From blue jeans to blue genes.

    Science.gov (United States)

    Boon, Laurence M; Vikkula, Miikka

    2009-03-01

    Cutaneous venous anomalies are common. They are blue and vary in size, number, and location and account for most consultations at specialized interdisciplinary clinics for vascular anomalies. Venous lesions are clinically important because they cause pain, dysfunction, destruction of adjacent tissues, and esthetic concern. Only resection and sclerotherapy are helpful, although not always curative. Understanding etiopathogenesis could help design animal models and develop novel therapeutic approaches. John B. Mulliken, MD, envisioned a project to uncover the genetic basis of an inherited form of venous malformation in a large New England family. Recruitment of 2 young fellows resulted in a collaborative project that unraveled the searched-for gene and its mutation. This was an opening for a new era in vascular anomalies. Two blue genes' mutations were discovered, which account for most, if not all, of the inherited forms of venous anomalies, but other genes as well, for rheologically diverse lesions. Differential diagnosis and management has improved, and animal models are being made. This was achieved through the help of Dr Mulliken, who inspired 2 young investigators in blue jeans to find 2 blue genes.

  6. Giant Magneto-Impedance Effect in Fe96-xZrxB4 (x=7 or 10)Nanocrystalline Ribbons

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The total ribbon voltage of as-quenched and annealed Fe96-xZrxB4 (x=7 or 10) ribbons has been measured as a function of applied dc field and drive current frequency. The experimental results show that both samples exist the optimum annealing temperature and optimum frequency at which the relative change in ribbon voltage is strongest, and the sensitivity of the magnetic response of the annealed Fe89Zr7B4 ribbon is two order of magnitude larger than that of the annealed Fe86Zr10B4 ribbon. The effect of magnetic properties and structural characteristics on giant magneto-impedance was discussed.

  7. Magnetostriction and microstructure of the melt-spun Fe83Ga17 alloy ribbons

    Institute of Scientific and Technical Information of China (English)

    ZHANG Maocai; GAO Xuexu; JIANG Honglin; ZHU Jie; ZHOU Shouzeng

    2007-01-01

    Fe83Ga17 alloy ribbons with four thicknesses were prepared by the melt-spun method.The measured results show that magnetostriction is related to the thickness of the ribbons,and its maximum value,-2100 ppm,has been obtained in the ribbon with a thickness of 75 μm.The results of the X-ray diffraction (XRD) and the differential scanning caloric (DSC) show that a phase with DO3 structure emerges in those ribbons with the thicknesses of 45,55 and 75 μm,and a phase transition of A2 + DO2 →A2 occurred at 669℃ for the ribbon with the thickness of 75 μm.The increase in the cool-ing rate can restrain the precipitation of the Ga-rich phase in the ribbon.It is considered that the giant magnetostriction of ribbons originates from the A2 + special DO3 structure and shape magnetic anisotropy.

  8. The energy-dependent position of the IBEX ribbon due to the solar wind structure

    CERN Document Server

    Swaczyna, Paweł; Sokół, Justyna M

    2016-01-01

    Observations of energetic neutral atoms (ENAs) allow for remote studies of the plasma condition in the heliosphere and the neighboring local interstellar medium. The first IBEX results revealed an arc-like enhancement of the ENA flux in the sky, known as the ribbon. The ribbon was not expected from the heliospheric models prior to the IBEX launch. One of the proposed explanations of the ribbon is the mechanism of the secondary ENA emission. The ribbon reveals energy-dependent structure in the relative intensity along its circumference and in the position. Namely, the ribbon geometric center varies systematically by about 10$^\\circ$ in the energy range 0.7-4.3 keV. Here, we show by analytic modeling that this effect is a consequence of the helio-latitudinal structure of the solar wind reflected in the secondary ENAs. Along with a recently measured distance to the ribbon source just beyond the heliopause, our findings support the connection of the ribbon with the local interstellar magnetic field by the mechani...

  9. SYMMETRY OF THE IBEX RIBBON OF ENHANCED ENERGETIC NEUTRAL ATOM (ENA) FLUX

    Energy Technology Data Exchange (ETDEWEB)

    Funsten, H. O.; Cai, D. M.; Higdon, D. M.; Larsen, B. A., E-mail: hfunsten@lanl.gov, E-mail: dmc@lanl.gov, E-mail: dhigdon@lanl.gov, E-mail: balarsen@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); and others

    2015-01-20

    The circular ribbon of enhanced energetic neutral atom (ENA) emission observed by the Interstellar Boundary Explorer (IBEX) mission remains a critical signature for understanding the interaction between the heliosphere and the interstellar medium. We study the symmetry of the ribbon flux and find strong, spectrally dependent reflection symmetry throughout the energy range 0.7-4.3 keV. The distribution of ENA flux around the ribbon is predominantly unimodal at 0.7 and 1.1 keV, distinctly bimodal at 2.7 and 4.3 keV, and a mixture of both at 1.7 keV. The bimodal flux distribution consists of partially opposing bilateral flux lobes, located at highest and lowest heliographic latitude extents of the ribbon. The vector between the ribbon center and heliospheric nose (which defines the so-called BV plane) appears to play an organizing role in the spectral dependence of the symmetry axis locations as well as asymmetric contributions to the ribbon flux. The symmetry planes at 2.7 and 4.3 keV, derived by projecting the symmetry axes to a great circle in the sky, are equivalent to tilting the heliographic equatorial plane to the ribbon center, suggesting a global heliospheric ordering. The presence and energy dependence of symmetric unilateral and bilateral flux distributions suggest strong spectral filtration from processes encountered by an ion along its journey from the source plasma to its eventual detection at IBEX.

  10. A novel method for estimating solid fraction of roller-compacted ribbons.

    Science.gov (United States)

    Nkansah, Paul; Wu, Sy-Juen; Sobotka, Stephanie; Yamamoto, Ken; Shao, Zezhi J

    2008-02-01

    A simple method has been developed to estimate solid fraction or relative density of compacts using the weight of ribbons produced during roller compaction. The method provides an alternative to the commonly used dimensional measurement, especially for formulations not amenable to forming quality ribbons. Surface texture of the compaction rolls has been taken into consideration in our mathematical treatment along with correction for ribbon relaxation. Ribbon relaxation occurring upon ribbon exiting the compaction zone is estimated using roll geometry, roll gap, and ribbon thickness. Detailed experimental runs have been carried out to confirm the validity of the proposed theory. The predicted solid fraction was found comparable to that from actual dimensional measurement by caliper. In the case of the microcrystalline cellulose/dicalcium phosphate one:one formulation, the predicted solid fraction had an error sum of squares (SSE) of 2.64E-03 when compared to the dimensional method. When relaxation was included, the SSE decreased by four folds. Similarly, for the microcrystalline cellulose/lactose monohydrate 2:1 formulation, the SSE decreased twelfth folds when relaxation was taken into consideration. These results further confirm the utility of the proposed throughput method for estimating the solid fraction of ribbons.

  11. Silicon ribbon growth by a capillary action shaping technique. Quarterly technical progress report No. 2

    Energy Technology Data Exchange (ETDEWEB)

    Schwuttke, G.H.; Ciszek, T.F.; Kran, A.

    1975-01-01

    Progress during the second quarter of the contractual effort is described. The work performed related mainly to ribbon growth by a capillary action shaping technique and to ribbon characterization. Actual progress in the crystal growth area includes the evaluation of 10 potential die materials other than carbon and the process development for 25-mm-wide ribon. From the die study it is concluded that boron carbide, silicon carbide, and silicon nitride may warrant further investigation as die materials. Process development for 25-mm ribbon growth resulted in ribbons of superior surface quality. Potential ribbongrowth problems encountered and discussed include a boron doping anomaly and frozen-in stresses in ribbons. The characterization effort concentrated on the development of a solar-cell process to be used for ribbon characterization. Material requirements and detailed process procedures are given. Solar cells fabricated by this process are compared with commercially available solar cells and compare favorably. A transmission electron microscopy study of planar boundaries frequently observed in ribbon crystals is reported. (auth)

  12. Separation of the Interstellar Boundary Explorer Ribbon from Globally Distributed Energetic Neutral Atom Flux

    Science.gov (United States)

    Schwadron, N. A.; Allegrini, F.; Bzowski, M.; Christian, E. R.; Crew, G. B.; Dayeh, M.; DeMajistre, R.; Frisch, P.; Funsten, H. O.; Fuselier, S. A.; Goodrich, K.; Gruntman, M.; Janzen, P.; Kucharek, H.; Livadiotis, G.; McComas, D. J.; Moebius, E.; Prested, C.; Reisenfeld, D.; Reno, M.; Roelof, E.; Siegel, J.; Vanderspek, R.

    2011-04-01

    The Interstellar Boundary Explorer (IBEX) observes a remarkable feature, the IBEX ribbon, which has energetic neutral atom (ENA) flux over a narrow region ~20° wide, a factor of 2-3 higher than the more globally distributed ENA flux. Here, we separate ENA emissions in the ribbon from the distributed flux by applying a transparency mask over the ribbon and regions of high emissions, and then solve for the distributed flux using an interpolation scheme. Our analysis shows that the energy spectrum and spatial distribution of the ribbon are distinct from the surrounding globally distributed flux. The ribbon energy spectrum shows a knee between ~1 and 4 keV, and the angular distribution is approximately independent of energy. In contrast, the distributed flux does not show a clear knee and more closely conforms to a power law over much of the sky. Consistent with previous analyses, the slope of the power law steepens from the nose to tail, suggesting a weaker termination shock toward the tail as compared to the nose. The knee in the energy spectrum of the ribbon suggests that its source plasma population is generated via a distinct physical process. Both the slope in the energy distribution of the distributed flux and the knee in the energy distribution of the ribbon are ordered by latitude. The heliotail may be identified in maps of globally distributed flux as a broad region of low flux centered ~44°W of the interstellar downwind direction, suggesting heliotail deflection by the interstellar magnetic field.

  13. Blue ocean strategy.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2004-10-01

    Despite a long-term decline in the circus industry, Cirque du Soleil profitably increased revenue 22-fold over the last ten years by reinventing the circus. Rather than competing within the confines of the existing industry or trying to steal customers from rivals, Cirque developed uncontested market space that made the competition irrelevant. Cirque created what the authors call a blue ocean, a previously unknown market space. In blue oceans, demand is created rather than fought over. There is ample opportunity for growth that is both profitable and rapid. In red oceans--that is, in all the industries already existing--companies compete by grabbing for a greater share of limited demand. As the market space gets more crowded, prospects for profits and growth decline. Products turn into commodities, and increasing competition turns the water bloody. There are two ways to create blue oceans. One is to launch completely new industries, as eBay did with online auctions. But it's much more common for a blue ocean to be created from within a red ocean when a company expands the boundaries of an existing industry. In studying more than 150 blue ocean creations in over 30 industries, the authors observed that the traditional units of strategic analysis--company and industry--are of limited use in explaining how and why blue oceans are created. The most appropriate unit of analysis is the strategic move, the set of managerial actions and decisions involved in making a major market-creating business offering. Creating blue oceans builds brands. So powerful is blue ocean strategy, in fact, that a blue ocean strategic move can create brand equity that lasts for decades.

  14. Paramagnetic colloidal ribbons in a precessing magnetic field

    Science.gov (United States)

    Alvarez-Nodarse, R.; Quintero, N. R.; Mertens, F. G.; Casic, N.; Fischer, Th. M.

    2015-03-01

    We investigate the dynamics of a kink in a damped parametrically driven nonlinear Klein-Gordon equation. We show by using a method of averaging that, in the high-frequency limit, the kink moves in an effective potential and is driven by an effective constant force. We demonstrate that the shape of the solitary wave can be controlled via the frequency and the eccentricity of the modulation. This is in accordance with the experimental results reported in a recent paper [Casic et al., Phys. Rev. Lett. 110, 168302 (2013), 10.1103/PhysRevLett.110.168302], where the dynamic self-assembly and propulsion of a ribbon formed from paramagnetic colloids in a time-dependent magnetic field has been studied.

  15. Paramagnetic colloidal ribbons in a precessing magnetic field.

    Science.gov (United States)

    Alvarez-Nodarse, R; Quintero, N R; Mertens, F G; Casic, N; Fischer, Th M

    2015-03-01

    We investigate the dynamics of a kink in a damped parametrically driven nonlinear Klein-Gordon equation. We show by using a method of averaging that, in the high-frequency limit, the kink moves in an effective potential and is driven by an effective constant force. We demonstrate that the shape of the solitary wave can be controlled via the frequency and the eccentricity of the modulation. This is in accordance with the experimental results reported in a recent paper [Casic et al., Phys. Rev. Lett. 110, 168302 (2013)], where the dynamic self-assembly and propulsion of a ribbon formed from paramagnetic colloids in a time-dependent magnetic field has been studied.

  16. Thin-ribbon tapered coupler for dielectric waveguides

    Science.gov (United States)

    Yeh, C.; Otoshi, T. Y.; Shimabukuro, F. I.

    1994-05-01

    A recent discovery shows that a high-dielectric constant, low-loss, solid material can be made into a ribbon-like waveguide structure to yield an attenuation constant of less than 0.02 dB/m for single-mode guidance of millimeter/submillimeter waves. One of the crucial components that must be invented in order to guarantee the low-loss utilization of this dielectric-waveguide guiding system is the excitation coupler. The traditional tapered-to-a-point coupler for a dielectric rod waveguide fails when the dielectric constant of the dielectric waveguide is large. This article presents a new way to design a low-loss coupler for a high- or low-dielectric constant dielectric waveguide for millimeter or submillimeter waves.

  17. Quantitative analysis of ribbons, vesicles, and cisterns at the cat inner hair cell synapse: correlations with spontaneous rate.

    Science.gov (United States)

    Kantardzhieva, Albena; Liberman, M Charles; Sewell, William F

    2013-10-01

    Cochlear hair cells form ribbon synapses with terminals of the cochlear nerve. To test the hypothesis that one function of the ribbon is to create synaptic vesicles from the cisternal structures that are abundant at the base of hair cells, we analyzed the distribution of vesicles and cisterns around ribbons from serial sections of inner hair cells in the cat, and compared data from low and high spontaneous rate (SR) synapses. Consistent with the hypothesis, we identified a "sphere of influence" of 350 nm around the ribbon, with fewer cisterns and many more synaptic vesicles. Although high- and low-SR ribbons tended to be longer and thinner than high-SR ribbons, the total volume of the two ribbon types was similar. There were almost as many vesicles docked at the active zone as attached to the ribbon. The major SR-related difference was that low-SR ribbons had more synaptic vesicles intimately associated with them. Our data suggest a trend in which low-SR synapses had more vesicles attached to the ribbon (51.3 vs. 42.8), more docked between the ribbon and the membrane (12 vs. 8.2), more docked at the active zone (56.9 vs. 44.2), and more vesicles within the "sphere of influence" (218 vs. 166). These data suggest that the structural differences between high- and low-SR synapses may be more a consequence, than a determinant, of the physiological differences.

  18. Magnetoimpedance exchange coupling in different magnetic strength thin layers electrodeposited on Co-based magnetic ribbons

    Science.gov (United States)

    Jamilpanah, L.; Hajiali, M. R.; Morteza Mohseni, S.; Erfanifam, S.; Majid Mohseni, S.; Houshiar, M.; Ehsan Roozmeh, S.

    2017-04-01

    A systematic study of the effect of the deposition of cobalt (Co) and nickel (Ni) layers of various thicknesses on the magnetoimpedance (MI) response of a soft ferromagnetic amorphous ribbon (Co68.15Fe4.35Si12.5B15) is performed. The Co and Ni layers with thicknesses of 5, 10, 20 and 40 nm were grown on both sides of the amorphous ribbons by the electrodeposition technique. Microstrutures determined by x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) showed higher crystallinity of Ni-deposited layers and the amorphous ferromagnetic nature of Co-deposited. The vibrating sample magnetometry (VSM) does not represent significant changes between samples because of the small contribution of such a thin layer deposited on thick ribbons, but the MI response dictates that the magnetic coupling effect occurred at the interface of such bilayers, which is sensitive to the skin effect. The MI response of Co-deposited ribbons showed MI hysteretic behavior depending on the deposited layer thicknesses with an optimum response for the thickness of 20 nm whereas no hysteretic behavior was measured for Ni-deposited ribbons. This behavior is explained according to the exchange coupling between magnetization of electrodeposited layers and magnetic ribbons with respect to different magnetic properties of Co and Ni at different thicknesses. Also the MI response of Ni- and Co-deposited ribbons enhanced significantly at low thicknesses relative to bare ribbon. By increasing the thickness of deposited layers, MI response decreases considerably. Differences in MI ratios of Co- and Ni-deposited ribbons are explained according to exchange length, crystallinity and roughness of deposited layers. Our results could address a simple way to achieve a higher MI response, and explains physical aspects of exchange coupling in MI response all towards a better performance of magnetic field sensors.

  19. Le blue-jean

    OpenAIRE

    Miller, Daniel

    2012-01-01

    Le Blue-jean: pourquoi la technologie vient en dernier. La plupart des personnes pensent que la technique (ou la technologie) correspond à ce qui vient en amont du produit. Dans cet article, Daniel Miller s’intéresse plutôt à des cas dans lesquels l’ordre de la séquence est renversé et où le produit précède, ou initie, en quelque sorte, la technique. L’auteur commence par décrire les techniques d’usure artificielle des blue jeans  : une technique qui vise à copier les effets du port des blue ...

  20. Simulation of non-Abelian anyons using ribbon operators connected to a common base site

    Energy Technology Data Exchange (ETDEWEB)

    Luo Xiwang; Han Yongjian; Guo Guangcan; Zhou Xingxiang; Zhou Zhengwei [Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2011-11-15

    A convenient and effective way in the quantum double model to study anyons in a topological space with a tensor product structure is to create and braid anyons using ribbon operators connected to a common base site [A. Kitaev, Ann. Phys. (NY) 303, 2 (2003)]. We show how this scheme can be simulated in a physical system by constructing long ribbon operators connected to a base site that is placed far away. We describe how to move and braid anyons using these ribbon operators, and how to perform measurement on them. We also give the smallest scale of a system that is sufficient for proof-of-principle demonstration of our scheme.

  1. Dynamic changes in hair cell ribbon synapse induced by loss of spiral ganglion neurons in mice

    Institute of Scientific and Technical Information of China (English)

    Yuan Yasheng; Chi Fanglu

    2014-01-01

    Background Previous studies have suggested that primary degeneration of hair cells causes secondary degeneration of spiral ganglion neurons (SGNs),but the effect of SGN degeneration on hair cells has not been studied.In the adult mouse inner ear ouabain can selectively and permanently induce the degeneration of type 1 SGNs while leaving type 2 SGNs,efferent fibers,and sensory hair cells relatively intact.This study aimed to investigate the dynamic changes in hair cell ribbon synapse induced by loss of SGNs using ouabain application to the round window niche of adult mice.Methods In the analysis,24 CBA/CAJ mice aged 8-10 weeks,were used,of which 6 normal mice were used as the control group.After ouabain application in the round window niche 6 times in an hour,ABR threshold shifts at least 30 dB in the three experimental groups which had six mice for 1-week group,six for 1-month group,and six for 3-month group.All 24 animals underwent function test at 1 week and then immunostaining at 1 week,1 month,and 3 months.Results The loss of neurons was followed by degeneration of postsynaptic specializations at the afferent synapse with hair cells.One week after ouabain treatment,the nerve endings of type 1 SGNs and postsynaptic densities,as measured by Na/K ATPase and PSD-95,were affected but not entirely missing,but their partial loss had consequences for synaptic ribbons that form the presynaptic specialization at the synapse between hair cells and primary afferent neurons.Ribbon numbers in inner hair cells decreased (some of them broken and the ribbon number much decreased),and the arrangement of the synaptic ribbons had undergone a dynamic reorganization:ribbons with or without associated postsynaptic densities moved from their normal location in the basal membrane of the cell to a more apical location and the neural endings alone were also found at more apical locations without associated ribbons.After 1 month,when the neural postsynaptic densities had completed their

  2. An AFM investigation of the mesostructure of Fe-based nanocrystalline ribbon

    Institute of Scientific and Technical Information of China (English)

    FANG Yunzhang; WU Fengmin; WU Wenhui; ZHENG Jinju; YANG Xiaohong; SI Jianxiao; SUN Huanjun; LOU Rongxun; ZHANG Fufei

    2004-01-01

    The mesostructure at the cross section of the Fe-based nanocrystalline (Fe73.5Cu1Nb3Si13.5B9) ribbon was observed with atomic force microscopy (AFM). An apparent mesostructural difference was found between the sticking roller face area (SRFA) and the free face area (FFA) of the ribbon crystallized after annealing. In SRFA there is a preponderance of rough grain gathering in longitudinal arrangement, while in FFA a fine grain gathering arranged transversely dominates. This phenomenon could be due to the different residual stress remained in the different areas of the amorphous ribbon resulting from the single-roller quenching technique.

  3. FROM BLUE JEANS TO BLUE GENES

    OpenAIRE

    Boon, Laurence M.; Vikkula, Miikka

    2009-01-01

    Cutaneous venous anomalies are common. They are blue in color and vary in size, number and location, and account for the majority of consultations at specialized interdisciplinary clinics for vascular anomalies. Venous lesions are clinically important as they cause pain, dysfunction, destruction of adjacent tissues and esthetic concern. Only resection and sclerotherapy are helpful, although not always curative. Understanding etiopathogenesis could help design animal models and develop novel t...

  4. New York Blue

    Data.gov (United States)

    Federal Laboratory Consortium — New York Blue is used cooperatively by the Laboratory and Stony Brook University as part of the New York Center for Computation Sciences. Ranked as the 28th fastest...

  5. Methylene blue test

    Science.gov (United States)

    Methemoglobinemia - methylene blue test ... No special preparation is required for this test. ... which are genetic (problem with your genes). This test is used to tell the difference between methemoglobinemia ...

  6. Magnetic Properties of Fe- and FeNi-based Amorphous Composite Ribbons

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    M8-T curves and hysteresis loops were investigated for amorphous Fe78Si9B13, (FeNi)78(CrSiB)22, their lap-wound-cores, and their composite ribbons made by two-chamber-crucible technique. The properties of the lap-wound cores of the two kinds of ribbons are similar. For the composite ribbons, the intrinsic properties are the average of the two alloys. Their technological properties, i.e., hysteresis loops, however, are no longer the average of the two alloys. Instead, they show some dramatic changes compared to the lap-wound-cores. Especially, the shape of the hysteresis loop of the composite ribbon cores is largely different from that of lap-wound-cores. The reason for the difference is supposed to be internal stress induced from cooling after annealing.

  7. Short range order transformation and magnetostriction of Fe83Ga17 ribbons

    Institute of Scientific and Technical Information of China (English)

    Zhu Jie; Peng Fu-Ling; Fang Mei-Ling; Li Ji-Heng; Gao Xue-Xu; Yu Rong-Hai

    2011-01-01

    The relationship between magnetostriction and structure of melt-spun Fe83Ga17 ribbons are investigated by XRD and Mossbauer spectrum technique (MS). As the heat-treatment temperature increases from 650℃ to 800℃, the magnetostriction coefficient of Fe83Ga17 ribbon first increases and then decreases. The largest magnetostriction coefficient (-578.4 ppm) is achieved in those specimens quenched at 750℃. According to the XRD and M(o)ssbauer spectrum analysis, a small quantity of DO3 phase is precipitated in Fe83Ga17 ribbons when quenched from 650℃ and the DO3 phase is gradually transformed into B2-like phase if quenched at higher temperature. However, both DO3 and B2-like phases disappear when the temperature increases up to 800℃. From this point of view, B2-like phase might be beneficial to the enhancement of magnetostrictive properties of melt-spun ribbons.

  8. Continuum Elasticity Theory Approach for Spontaneous Bending and Twisting of Ribbons Induced by Mechanical Anisotropy

    CERN Document Server

    Chen, Zi; Srolovitz, David J; Haataja, Mikko

    2012-01-01

    Helical ribbons arise in many biological and engineered systems, often driven by anisotropic surface stress, residual strain, and geometric or elastic mismatch between layers of a laminated composite. A full mathematical analysis is developed to analytically predict the equilibrium deformed helical shape of an initially flat, straight ribbon, with prescribed magnitudes and orientations of the principal curvatures when subjected to arbitrary surface stress and/or internal residual strain distribution. The helix angle, radius, axis and chirality of the deformed helical ribbons are predicted with a comprehensive, three-dimensional model that incorporates elasticity, differential geometry, and variational principles. In general, the mechanical anisotropy (e.g., in surface/external stress, residual strain or elastic modulus) will lead to spontaneous, three-dimensional helical deformations. Ring shapes are formed when the principle axes of deformation coincide with the geometric axes of the ribbon. The transition f...

  9. Plasmon resonances in a stacked pair of graphene ribbon arrays with a lateral displacement.

    Science.gov (United States)

    He, Meng-Dong; Zhang, Gui; Liu, Jian-Qiang; Li, Jian-Bo; Wang, Xin-Jun; Huang, Zhen-Rong; Wang, Lingling; Chen, Xiaoshuang

    2014-03-24

    We find that a stacked pair of graphene ribbon arrays with a lateral displacement can excite plasmon waveguide mode in the gap between ribbons, as well as surface plasmon mode on graphene ribbon surface. When the resonance wavelengthes of plasmon waveguide mode and surface plasmon mode are close to each other, there is a strong electromagnetic interaction between the two modes, and then they contribute together to transmission dip. The plasmon waveguide mode resonance can be manipulated by the lateral displacement and longitudinal interval between arrays due to their influence on the manner and strength of electromagnetic coupling between two arrays. The findings expand our understanding of electromagnetic resonances in graphene-ribbon array structure and may affect further engineering of nanoplasmonic devices and metamaterials.

  10. Fabrication of Fe-based ribbon with controlled permeability by Joule heating under tensile stress

    Energy Technology Data Exchange (ETDEWEB)

    Yanai, T. [Department of Electrical and Electronic Engineering, Faculty of Engineering of the University of Nagasaki, Nagasaki 852-8521 (Japan)], E-mail: t-yanai@nagasaki-u.ac.jp; Takagi, K.; Takahashi, K.; Nakano, M. [Department of Electrical and Electronic Engineering, Faculty of Engineering of the University of Nagasaki, Nagasaki 852-8521 (Japan); Yoshizawa, Y. [Advanced Electronics Research Laboratory, Hitachi Metals Ltd., Kumagaya 360-0843 (Japan); Fukunaga, H. [Department of Electrical and Electronic Engineering, Faculty of Engineering of the University of Nagasaki, Nagasaki 852-8521 (Japan)

    2008-10-15

    We prepared an Fe-based ribbon with controlled permeability and low magnetic loss by continuous stress-annealing by joule heating (CSA-JH) method. The shortest annealing time necessary for the obtaining of the ribbons with completely developed anisotropy was 1 s, but in order to obtain the sufficiently crystallized ribbons with small saturation magnetostriction it is required to perform annealing longer than 2 s. A toroidal core was prepared from a long ribbon with controlled permeability and small saturation magnetostriction, and the magnetic loss and relative permeability of the core were evaluated in the frequency range of 0.1-3 MHz. The permeability was kept constant up to 2 MHz, and the magnetic loss is lower than that for other types of core with a similar permeability value. These results suggest that the CSA-JH method is a promising method for realizing an Fe-based core with excellent magnetic properties.

  11. Pressure stress-impedance effect in FeCuNbSiB amorphours ribbons

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The stress-impedance effect in Fe73.5Cu1Nb3Si13.5B9 (at%) ribbons is measured to investigate the influences of vacuum annealing and pressure stress. The results can be explained by the influence of induced anisotropy in the magnetization processes at the chosen drive current frequency of 90 MHz. The maximum SI% value of the ribbon annealed at 300 ℃ is 2.52%.

  12. Magnetic behaviour of amorphous ribbons with creep-induced helical anisotropy and their fluxgate properties

    DEFF Research Database (Denmark)

    Füzer, Jan; Brauer, Peter; Nielsen, Otto V

    1998-01-01

    We have induced a helical destributionby a tortional and tensile stress annealing, in low magnetostriction amorphous ribbons. In this paper we report a theoretical studyof predicted magnetisation curvesand the comparisonwith experimental measurements.......We have induced a helical destributionby a tortional and tensile stress annealing, in low magnetostriction amorphous ribbons. In this paper we report a theoretical studyof predicted magnetisation curvesand the comparisonwith experimental measurements....

  13. Reefing of Quarter Spherical Ribbon Parachutes Used in the Ares I First Stage Deceleration System

    Science.gov (United States)

    Schmidt, Jason R.; McFadden, Peter G.

    2009-01-01

    This paper introduces the parachutes that have been drop tested in support of the Ares I first stage deceleration system development. The results of the tests show that the reefing ratios for these quarter spherical ribbon parachutes provide the same reefed drag area as historical conical ribbon parachutes. Two sources are investigated for properly normalizing the parachutes relative to their suspension line length, and one is found to be superior.

  14. Magnetostriction Dependence of the Relaxation Frequency in the Magnetoimpedance Effect for Amorphous and Nanocrystalline Ribbons

    Institute of Scientific and Technical Information of China (English)

    M.L.Sánchez; V.M.Prida; B.Hernando; G.V.Kurlyandskaya; J.D.Santos; M.Tejedor; M.Vázquez

    2002-01-01

    The magnetoimpedance effect and changes of the relaxation frequency fx are studied in CoFeSiB and CoFeMoSiB amorphous and FeCuNbSiB nanocrystalline ribbons. The evolution of the magnetostriction constant λs and relaxation frequency is analysed for the states with different magnetic anisotropies induced in the same ribbons.A monotonic decrease of the relaxation frequency is observed for shifting of λs towards positive values.

  15. Using Two-Ribbon Flare Observations and MHD Simulations to Constrain Flare Properties

    Science.gov (United States)

    Kazachenko, Maria D.; Lynch, Benjamin J.; Welsch, Brian

    2016-05-01

    Flare ribbons are emission structures that are frequently observed during flares in transition-region and chromospheric radiation. These typically straddle a polarity inversion line (PIL) of the radial magnetic field at the photosphere, and move apart as the flare progresses. The ribbon flux - the amount of unsigned photospheric magnetic flux swept out by flare ribbons - is thought to be related to the amount coronal magnetic reconnection, and hence provides a key diagnostic tool for understanding the physical processes at work in flares and CMEs. Previous measurements of the magnetic flux swept out by flare ribbons required time-consuming co-alignment between magnetograph and intensity data from different instruments, explaining why those studies only analyzed, at most, a few events. The launch of the Helioseismic and Magnetic Imager (HMI) and the Atmospheric Imaging Assembly (AIA), both aboard the Solar Dynamics Observatory (SDO), presented a rare opportunity to compile a much larger sample of flare-ribbon events than could readily be assembled before. We created a dataset of 363 events of both flare ribbon positions and fluxes, as a function of time, for all C9.-class and greater flares within 45 degrees of disk center observed by SDO from June 2010 till April 2015. For this purpose, we used vector magnetograms (2D magnetic field maps) from HMI and UV images from AIA. A critical problem with using unprocessed AIA data is the existence of spurious intensities in AIA data associated with strong flare emission, most notably "blooming" (spurious smearing of saturated signal into neighboring pixels, often in streaks). To overcome this difficulty, we have developed an algorithmic procedure that effectively excludes artifacts like blooming. We present our database and compare statistical properties of flare ribbons, e.g. evolutions of ribbon reconnection fluxes, reconnection flux rates and vertical currents with the properties from MHD simulations.

  16. Modulation of bandgap in bilayer armchair graphene ribbons by tuning vertical and transverse electric fields

    Science.gov (United States)

    Vu, Thanh-Tra; Nguyen, Thi-Kim-Quyen; Huynh, Anh-Huy; Phan, Thi-Kim-Loan; Tran, Van-Truong

    2017-02-01

    We investigate the effects of external electric fields on the electronic properties of bilayer armchair graphene nano-ribbons. Using atomistic simulations with Tight Binding calculations and the Non-equilibrium Green's function formalism, we demonstrate that (i) in semi-metallic structures, vertical fields impact more effectively than transverse fields in terms of opening larger bandgap, showing a contrary phenomenon compared to that demonstrated in previous studies in bilayer zigzag graphene nano-ribbons; (ii) in some semiconducting structures, if transverse fields just show usual effects as in single layer armchair graphene nano-ribbons where the bandgap is suppressed when varying the applied potential, vertical fields exhibit an anomalous phenomenon that the bandgap can be enlarged, i.e., for a structure of width of 16 dimer lines, the bandgap increases from 0.255 eV to the maximum value of 0.40 eV when a vertical bias equates 0.96 V applied. Although the combined effect of two fields does not enlarge the bandgap as found in bilayer zigzag graphene nano-ribbons, it shows that the mutual effect can be useful to reduce faster the bandgap in semiconducting bilayer armchair graphene nano-ribbons. These results are important to fully understand the effects of electric fields on bilayer graphene nano-ribbons (AB stacking) and also suggest appropriate uses of electric gates with different edge orientations.

  17. Myosin VI is required for the proper maturation and function of inner hair cell ribbon synapses.

    Science.gov (United States)

    Roux, Isabelle; Hosie, Suzanne; Johnson, Stuart L; Bahloul, Amel; Cayet, Nadège; Nouaille, Sylvie; Kros, Corné J; Petit, Christine; Safieddine, Saaid

    2009-12-01

    The ribbon synapses of auditory inner hair cells (IHCs) undergo morphological and electrophysiological transitions during cochlear development. Here we report that myosin VI (Myo6), an actin-based motor protein involved in genetic forms of deafness, is necessary for some of these changes to occur. By using post-embedding immunogold electron microscopy, we showed that Myo6 is present at the IHC synaptic active zone. In Snell's waltzer mutant mice, which lack Myo6, IHC ionic currents and ribbon synapse maturation proceeded normally until at least post-natal day 6. In adult mutant mice, however, the IHCs displayed immature potassium currents and still fired action potentials, as normally only observed in immature IHCs. In addition, the number of ribbons per IHC was reduced by 30%, and 30% of the remaining ribbons were morphologically immature. Ca2+-dependent exocytosis probed by capacitance measurement was markedly reduced despite normal Ca2+ currents and the large proportion of morphologically mature synapses, which suggests additional defects, such as loose Ca2+-exocytosis coupling or inefficient vesicular supply. Finally, we provide evidence that Myo6 and otoferlin, a putative Ca2+ sensor of synaptic exocytosis also involved in a genetic form of deafness, interact at the IHC ribbon synapse, and we suggest that this interaction is involved in the recycling of synaptic vesicles. Our findings thus uncover essential roles for Myo6 at the IHC ribbon synapse, in addition to that proposed in membrane turnover and anchoring at the apical surface of the hair cells.

  18. The Energy-Dependent Position of the IBEX Ribbon Due to the Solar Wind Structure

    Science.gov (United States)

    Swaczyna, Paweł; Bzowski, Maciej; Sokół, Justyna M.

    2016-08-01

    Observations of energetic neutral atoms (ENAs) allow for remote studies of the condition of plasma in the heliosphere and the neighboring local interstellar medium. The first results from the Interstellar Boundary Explorer (IBEX) revealed an arc-like enhancement of the ENA intensity in the sky, known as the ribbon. The ribbon was not expected from the heliospheric models prior to the launch of IBEX. One proposed explanation for the ribbon is the mechanism of secondary ENA emission. The ribbon reveals energy-dependent structure in the relative intensity along its circumference and in its position. That is, the geometric center of the ribbon varies systematically by about 10° in the energy range 0.7-4.3 keV. Here, we show by analytical modeling that this effect is a consequence of the helio-latitudinal structure of the solar wind reflected in the secondary ENAs. Along with a recently measured distance to the ribbon’s source just beyond the heliopause, our findings support the connection of the ribbon with the local interstellar magnetic field by the mechanism of secondary ENA emission. However, the magnitude of the center shift in the highest IBEX energy channel is much larger in the observations than expected from the modeling. This may be due to another, not currently recognized, process of ENA generation.

  19. Wearable energy-smart ribbons for synchronous energy harvest and storage

    Science.gov (United States)

    Li, Chao; Islam, Md. Monirul; Moore, Julian; Sleppy, Joseph; Morrison, Caleb; Konstantinov, Konstantin; Dou, Shi Xue; Renduchintala, Chait; Thomas, Jayan

    2016-11-01

    A promising energy source for many current and future applications is a ribbon-like device that could simultaneously harvest and store energy. Due to the high flexibility and weavable property, a fabric/matrix made using these ribbons could be highly beneficial for powering wearable electronics. Unlike the approach of using two separate devices, here we report a ribbon that integrates a solar cell and a supercapacitor. The electrons generated by the solar cell are directly transferred and stored on the reverse side of its electrode which in turn also functions as an electrode for the supercapacitor. When the flexible solar ribbon is illuminated with simulated solar light, the supercapacitor holds an energy density of 1.15 mWh cm-3 and a power density of 243 mW cm-3. Moreover, these ribbons are successfully woven into a fabric form. Our all-solid-state ribbon unveils a highly flexible and portable self-sufficient energy system with potential applications in wearables, drones and electric vehicles.

  20. Capillary origami: superhydrophobic ribbon surfaces and liquid marbles

    Science.gov (United States)

    Newton, Michael I; Shirtcliffe, Neil J; Geraldi, Nicasio R

    2011-01-01

    Summary In the wetting of a solid by a liquid it is often assumed that the substrate is rigid. However, for an elastic substrate the rigidity depends on the cube of its thickness and so reduces rapidly as the substrate becomes thinner as it approaches becoming a thin sheet. In such circumstances, it has been shown that the capillary forces caused by a contacting droplet of a liquid can shape the solid rather than the solid shaping the liquid. A substrate can be bent and folded as a (pinned) droplet evaporates or even instantaneously and spontaneously wrapped on contact with a droplet. When this effect is used to create three dimensional shapes from initially flat sheets, the effect is called capillary origami or droplet wrapping. In this work, we consider how the conditions for the spontaneous, capillary induced, folding of a thin ribbon substrate might be altered by a rigid surface structure that, for a rigid substrate, would be expected to create Cassie–Baxter and Wenzel effects. For smooth thin substrates, droplet wrapping can occur for all liquids, including those for which the Young’s law contact angle (defined by the interfacial tensions) is greater than 90° and which would therefore normally be considered relatively hydrophobic. However, consideration of the balance between bending and interfacial energies suggests that the tendency for droplet wrapping can be suppressed for some liquids by providing the flexible solid surface with a rigid topographic structure. In general, it is known that when a liquid interacts with such a structure it can either fully penetrate the structure (the Wenzel case) or it can bridge between the asperities of the structure (the Cassie–Baxter case). In this report, we show theoretically that droplet wrapping should occur with both types of solid–liquid contact. We also derive a condition for the transition between the Cassie–Baxter and Wenzel type droplet wrapping and relate it to the same transition condition known to

  1. Capillary origami: superhydrophobic ribbon surfaces and liquid marbles

    Directory of Open Access Journals (Sweden)

    Glen McHale

    2011-03-01

    Full Text Available In the wetting of a solid by a liquid it is often assumed that the substrate is rigid. However, for an elastic substrate the rigidity depends on the cube of its thickness and so reduces rapidly as the substrate becomes thinner as it approaches becoming a thin sheet. In such circumstances, it has been shown that the capillary forces caused by a contacting droplet of a liquid can shape the solid rather than the solid shaping the liquid. A substrate can be bent and folded as a (pinned droplet evaporates or even instantaneously and spontaneously wrapped on contact with a droplet. When this effect is used to create three dimensional shapes from initially flat sheets, the effect is called capillary origami or droplet wrapping.In this work, we consider how the conditions for the spontaneous, capillary induced, folding of a thin ribbon substrate might be altered by a rigid surface structure that, for a rigid substrate, would be expected to create Cassie–Baxter and Wenzel effects. For smooth thin substrates, droplet wrapping can occur for all liquids, including those for which the Young’s law contact angle (defined by the interfacial tensions is greater than 90° and which would therefore normally be considered relatively hydrophobic. However, consideration of the balance between bending and interfacial energies suggests that the tendency for droplet wrapping can be suppressed for some liquids by providing the flexible solid surface with a rigid topographic structure. In general, it is known that when a liquid interacts with such a structure it can either fully penetrate the structure (the Wenzel case or it can bridge between the asperities of the structure (the Cassie–Baxter case.In this report, we show theoretically that droplet wrapping should occur with both types of solid–liquid contact. We also derive a condition for the transition between the Cassie–Baxter and Wenzel type droplet wrapping and relate it to the same transition condition

  2. Atypical cellular blue nevus or malignant blue nevus?*

    Science.gov (United States)

    Daltro, Luise Ribeiro; Yaegashi, Lygia Bertalha; Freitas, Rodrigo Abdalah; Fantini, Bruno de Carvalho; Souza, Cacilda da Silva

    2017-01-01

    Blue nevus is a benign melanocytic lesion whose most frequent variants are dendritic (common) blue nevus and cellular blue nevus. Atypical cellular blue nevus presents an intermediate histopathology between the typical and a rare variant of malignant blue nevus/melanoma arising in a cellular blue nevus. An 8-year-old child presented a pigmented lesion in the buttock since birth, but with progressive growth in the last two years. After surgical excision, histopathological examination revealed atypical cellular blue nevus. Presence of mitoses, ulceration, infiltration, cytological atypia or necrosis may occur in atypical cellular blue nevus, making it difficult to differentiate it from melanoma. The growth of blue nevus is unusual and considered of high-risk for malignancy, being an indicator for complete resection and periodic follow-up of these patients. PMID:28225968

  3. Perversions driven spontaneous symmetry breaking in heterogeneous elastic ribbons

    Science.gov (United States)

    Liu, Shuangping; Yao, Zhenwei; Olvera de La Cruz, Monica

    2015-03-01

    Perversion structures in an otherwise uniform helical structure are associated with several important concepts in fundamental physics and materials science, including the spontaneous symmetry breaking and the elastic buckling. They also have strong connections with biological motifs (e.g., bacteria shapes and plant tendrils) and have potential applications in micro-muscles and soft robotics. In this work, using a three-dimensional elastomeric bi-stripe model, we investigate the properties of perversions that are independent of the specific ribbon shapes. Several intrinsic features of perversions are revealed, including the spontaneous condensation of energy as well as the distinct energy transfer modes within the perversion region. These properties of perversions associated with the storage of elastic energies can be exploited in the design of actuator devices. We thank the financial support from the U.S. Department of Commerce, National Institute of Standards and Technology, the Office of the Director of Defense Research and Engineering (DDR&E) and the Air Force Office of Scientific Research.

  4. Spectral Modulation of the IBEX Ribbon Flux by the Dynamic Draping of the Interstellar Medium over the Heliosphere

    Science.gov (United States)

    Funsten, H. O.; Pittman, K. T.; Frisch, P. C.; Heerikhuisen, J.; Janzen, P. H.; McComas, D. J.; Reisenfeld, D. B.; Schwadron, N.; Zirnstein, E.

    2015-12-01

    The bright energetic neutral atom (ENA) emission in the circular ribbon observed by the Interstellar Boundary Explorer (IBEX) ribbon is a key ordering parameter of the interaction region between the heliosphere and the insterstellar medium. The ribbon is hypothesized to result from the condition in which the interstellar magnetic field, which is draped over the heliosphere and is the emission location in the "secondary" reibbon hypothesis, is oriented perpendicular to the line-of-sight view from IBEX. Here, we consider the relative motion of the draped magnetic field line for modulating ribbon intensity. Using the 0.7 keV and 1.1 keV ENA maps from the IBEX-Hi instrument, we find that this relative motion may significantly contribute to the variation of ribbon flux around the ribbon. We discuss the implications of this relative motion on our understanding the global structure and dynamics of the heliosphere-insterstellar medium interaction.

  5. The Blue Collar Brain

    Directory of Open Access Journals (Sweden)

    Guy eVan Orden

    2012-06-01

    Full Text Available Much effort has gone into elucidating control of the body by the brain, less so the role of the body in controlling the brain. This essay develops the idea that the brain does a great deal of work in the service of behavior that is controlled by the body, a blue collar role compared to the white collar control exercised by the body. The argument that supports a blue collar role for the brain is also consistent with recent discoveries clarifying the white collar role of synergies across the body's tensegrity structure, and the evidence of critical phenomena in brain and behavior.

  6. A Blue Lagoon Function

    DEFF Research Database (Denmark)

    Markvorsen, Steen

    2007-01-01

    We consider a specific function of two variables whose graph surface resembles a blue lagoon. The function has a saddle point $p$, but when the function is restricted to any given straight line through $p$ it has a {\\em{strict local minimum}} along that line at $p$.......We consider a specific function of two variables whose graph surface resembles a blue lagoon. The function has a saddle point $p$, but when the function is restricted to any given straight line through $p$ it has a {\\em{strict local minimum}} along that line at $p$....

  7. After Stroke, 'Blue' Light May Help Beat the Blues

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_163731.html After Stroke, 'Blue' Light May Help Beat the Blues Akin ... a danger for people recovering from a debilitating stroke. But new research suggests that tweaking a rehabilitation ...

  8. Presynaptic [Ca2+] and GCAPs: aspects on the structure and function of photoreceptor ribbon synapses

    Directory of Open Access Journals (Sweden)

    Frank eSchmitz

    2014-02-01

    Full Text Available Changes in intracellular calcium ions [Ca2+] play important roles in photoreceptor signalling. Consequently, intracellular [Ca2+] levels need to be tightly controlled. In the light-sensitive outer segments (OS of photoreceptors, Ca2+ regulates the activity of retinal guanylate cyclases (ret-GCs thus playing a central role in phototransduction and light-adaptation by restoring light-induced decreases in cGMP. In the synaptic terminals, changes of intracellular Ca2+ trigger various aspects of neurotransmission. Photoreceptors employ tonically active ribbon synapses that encode light-induced, graded changes of membrane potential into different rates of synaptic vesicle exocytosis. The active zones of ribbon synapses contain large electron-dense structures, synaptic ribbons, that are associated with large numbers of synaptic vesicles. Synaptic coding at ribbon synapses differs from synaptic coding at conventional (phasic synapses. Recent studies revealed new insights how synaptic ribbons are involved in this process. This review focuses on the regulation of [Ca2+] in presynaptic photoreceptor terminals and on the function of a particular Ca2+-regulated protein, the neuronal calcium sensor protein GCAP2 (guanylate cyclase-activating protein-2 in the photoreceptor ribbon synapse. GCAP2, an EF hand-containing protein plays multiple roles in the OS and in the photoreceptor synapse. In the OS, GCAP2 works as a Ca2+-sensor within a Ca2+-regulated feedback loop that adjusts cGMP levels. In the photoreceptor synapse, GCAP2 binds to RIBEYE, a component of synaptic ribbons, and mediates Ca2+-dependent plasticity at that site. Possible mechanisms are discussed.

  9. Microstructure and microhardness of nanostructured Al-4.6Cu-Mn alloy ribbons

    Institute of Scientific and Technical Information of China (English)

    Zhong-wei Chen; Qin-ying Fan; Kai Zhao

    2015-01-01

    The microstructural characteristics and microhardness of nanostructured Al−4.6Cu−Mn ribbons produced by melt spinning were investigated using field-emission gun scanning electron microscopy, transmission electron microscopy, and hardness testing, and the results were compared to those of similar ribbons manufactured by direct-chill casting. It is shown that the nanostructure of the as-melt-spun ribbons consists ofα-Al dendrites with a secondary dendrite arm spacing of approximately 0.55−0.80μm and ultrafine eutectic crystals of a nanosized scale of approximately 100−200 nm on dendritic boundaries. The solidification time and cooling rate of 46-μm-thick ribbons were estimated to be 1.3 × 10−6 s and 4.04 × 106 K·s−1, respectively. At an aging temperature of 190°C, thecoherentθ″ phase in aged ribbons gradually transforms into nanoscaleθ′-phase platelets as the aging time is extended from 2 to 8 h; the rod-like morphology of the T (Al20Cu2Mn3) dispersoid with 120−160-nm diameter also forms, which results in peak aging hardness. The precipitation behaviors of aged ribbons cannot be changed at the high cooling rates of as-cast ribbons. However, a finer and more uniformly distributed microstructure and a supersaturated solid solution at a high cooling rate can shorten the time required to obtain a certain aging hardness before peak hardness.

  10. Silicon ribbon growth by a capillary action shaping technique. Annual report (Quarterly technical progress report No. 9)

    Energy Technology Data Exchange (ETDEWEB)

    Schwuttke, G.H.; Ciszek, T.F.; Kran, A.

    1977-10-01

    Progress on the technological and economical assessment of ribbon growth of silicon by a capillary action shaping technique is reported. Progress in scale-up of the process from 50 mm to 100 mm ribbon widths is presented, the use of vitreous carbon as a crucible material is analyzed, and preliminary tests of CVD Si/sub 3/N/sub 4/ as a potential die material are reported. Diffusion length measurements by SEM, equipment and procedure for defect display under MOS structure in silicon ribbon for lifetime interpretation, and an assessment of ribbon technology are discussed. (WHK)

  11. Plaque Type Blue Naevus

    Directory of Open Access Journals (Sweden)

    Sentamilselvi G

    1997-01-01

    Full Text Available A case of plaque type blue naevus was encountered in a Dermatology Clinic in Madras. The various clinical differential diagnoses are discussed, the hitopathological features described and the benign nature of the tumour stressed. The case is reported for its rarity and to create an awareness of this entity.

  12. Blue rubber bleb naevus

    Directory of Open Access Journals (Sweden)

    Mittal R

    1995-01-01

    Full Text Available A 35 year old female had multiple progressive painful, tender, soft, bluish compressible nodules with the feel of rubber nipples. There was no evidence of gastrointestinal haemangiomas or other systemic abnormalities. Histopathologically, cavernous haemangioma with prominent smooth muscle outline proved the clinical diagnosis of blue rubber bleb naevus. Only cutaneous lesions were seen in the patient.

  13. The "Blue Banana" Revisited

    NARCIS (Netherlands)

    Faludi, A.K.F.

    2015-01-01

    This essay is about the “Blue Banana”. Banana is the name given subsequently by others to a Dorsale européenne (European backbone) identified empirically by Roger Brunet. In a background study to the Communication of the European Commission ‘Europe 2000’, Klaus Kunzmann and Michael Wegener put forwa

  14. The Blue Denmark

    DEFF Research Database (Denmark)

    Hansen, Carsten Ørts; Sornn-Friese, Henrik

    This paper makes an important contribution to the discussion about knowledge based localised externalities in the context of shipping and the maritime sector in Denmark. In the paper we ask if there is a national, knowledge‐based maritime cluster configured around the shipowners in Denmark. This ...... talk about The Blue Denmark....

  15. Blue spectral inflation

    CERN Document Server

    Schunck, Franz E

    2008-01-01

    We reconsider the nonlinear second order Abel equation of Stewart and Lyth, which follows from a nonlinear second order slow-roll approximation. We find a new eigenvalue spectrum in the blue regime. Some of the discrete values of the spectral index n_s have consistent fits to the cumulative COBE data as well as to recent ground-base CMB experiments.

  16. Dark Blue II

    OpenAIRE

    2013-01-01

    Dark Blue II, high fired porcelain, decorated with cobalt chloride, woodfired with salt. 10,5 x 10,5 x 19 cm. Ferdigstilt: 2012. Innkjøpt til Collection of The American Museum of Ceramic Art, Pomona, California, USA.

  17. ILQINS hexapeptide, identified in lysozyme left-handed helical ribbons and nanotubes, forms right-handed helical ribbons and crystals.

    Science.gov (United States)

    Lara, Cecile; Reynolds, Nicholas P; Berryman, Joshua T; Xu, Anqiu; Zhang, Afang; Mezzenga, Raffaele

    2014-03-26

    Amyloid fibrils are implicated in over 20 neurodegenerative diseases. The mechanisms of fibril structuring and formation are not only of medical and biological importance but are also relevant for material science and nanotechnologies due to the unique structural and physical properties of amyloids. We previously found that hen egg white lysozyme, homologous to the disease-related human lysozyme, can form left-handed giant ribbons, closing into nanotubes. By using matrix-assisted laser desorption ionization mass spectrometry analysis, we here identify a key component of such structures: the ILQINS hexapeptide. By combining atomic force microscopy and circular dichorism, we find that this fragment, synthesized by solid-phase peptide synthesis, also forms fibrillar structures in water at pH 2. However, all fibrillar structures formed possess an unexpected right-handed twist, a rare chirality within the corpus of amyloid experimental observations. We confirm by small- and wide-angle X-ray scattering and molecular dynamics simulations that these fibrils are composed of conventional left-handed β-sheets, but that packing stresses between adjacent sheets create this twist of unusual handedness. We also show that the right-handed fibrils represent a metastable state toward β-sheet-based microcrystals formation.

  18. Calcium regulates vesicle replenishment at the cone ribbon synapse.

    Science.gov (United States)

    Babai, Norbert; Bartoletti, Theodore M; Thoreson, Wallace B

    2010-11-24

    Cones release glutamate-filled vesicles continuously in darkness, and changing illumination modulates this release. Because sustained release in darkness is governed by vesicle replenishment rates, we analyzed how cone membrane potential regulates replenishment. Synaptic release from cones was measured by recording postsynaptic currents in Ambystoma tigrinum horizontal or OFF bipolar cells evoked by depolarization of simultaneously voltage-clamped cones. We measured replenishment after attaining a steady state between vesicle release and replenishment using trains of test pulses. Increasing Ca(2+) currents (I(Ca)) by changing the test step from -30 to -10 mV increased replenishment. Lengthening -30 mV test pulses to match the Ca(2+) influx during 25 ms test pulses to -10 mV produced similar replenishment rates. Reducing Ca(2+) driving force by using test steps to +30 mV slowed replenishment. Using UV flashes to reverse inhibition of I(Ca) by nifedipine accelerated replenishment. Increasing [Ca(2+)](i) by flash photolysis of caged Ca(2+) also accelerated replenishment. Replenishment, but not the initial burst of release, was enhanced by using an intracellular Ca(2+) buffer of 0.5 mm EGTA rather than 5 mm EGTA, and diminished by 1 mm BAPTA. This suggests that although release and replenishment exhibited similar Ca(2+) dependencies, release sites are replenishment sites are >200 nm away. Membrane potential thus regulates replenishment by controlling Ca(2+) influx, principally by effects on replenishment mechanisms but also by altering releasable pool size. This in turn provides a mechanism for converting changes in light intensity into changes in sustained release at the cone ribbon synapse.

  19. Repeatable Shape Memory Effect and Mechanical Resonance of TiNiCu-Coated Magnetic Ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, O; Miyahara, Y; Kambe, S; Kutsuzawa, N [Yamagata University, Yonezawa, Yamagata 992-8510 (Japan); Ishida, A, E-mail: oishii@yz.yamagata-u.ac.jp [National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan)

    2011-01-01

    This paper describes a new bimorph-type actuator composed of a shape-memory-alloy coated magnetic ribbon. A high magnetostrictive amorphous ribbon (Metglas 2605SC, 37 mmx6 mmx0.025 mm) coated with a 1.0 {mu}m thick sputter-deposited Ti{sub 48.5}Ni{sub 33.5}Cu{sub 18} film exhibited a repeatable shape memory effect in the temperature range from 10 deg. C to 70 deg. C; reverse martensitic transformation upon heating bent the ribbon and martensitic transformation upon cooling flattened it. Simultaneous application of AC and DC magnetic fields excited the longitudinal mechanical vibration which can be monitored wirelessly with a pickup coil. The resonance frequency was proportional to the displacement of the ribbon within an accuracy of 0.76%. Consequently, it is confirmed that a TiNiCu-coated magnetic ribbon actuator with high positioning resolution can be realized by monitoring its resonance frequency and feeding back it to the heating and/or cooling power control algorithms.

  20. THE TRANSATLANTIC BLUE DIPLOMACY

    Directory of Open Access Journals (Sweden)

    Ioana GUTU

    2016-12-01

    Full Text Available The international diplomatic environment has reached to an unprecedented development, involving one of the newly specialized diplomatic types, namely the economic diplomacy. At the core of the fast movements in the diplomatic spheres across the Globe are the international agreements like the Transatlantic Trade and Investment Partnership (TTIP that determined diplomacy to dissolve into new subtypes, evolving from ground to the ocean and implementing new ways of achieving economic and climate sustainability. One of the newly created diplomatic spheres, is the blue ocean diplomacy that acts mainly in accordance with the rules and regulations that are being applied to the transatlantic economy. Even though TTIP encourages the increase of trade flows across the Atlantic, it will also ease the foreign investment procedures that, under the approach of keeping a sustainable environment, will represent one of the most important initiatives in implementing the blue economy concept within the framework of the transatlantic diplomacy.

  1. Faint Blue Galaxies

    CERN Document Server

    Ellis, Richard S

    1997-01-01

    The physical properties of the faint blue galaxy population are reviewed in the context of observational progress made via deep spectroscopic surveys and Hubble Space Telescope imaging of field galaxies at various limits, and theoretical models for the integrated star formation history of the Universe. Notwithstanding uncertainties in the properties of the local population of galaxies, convincing evidence has emerged from several independent studies for a rapid decline in the volume-averaged star formation rate of field galaxies since a redshift z~1. Together with the small angular sizes and modest mean redshift of the faintest detectable sources, these results can be understood in hierarchical models where the bulk of the star formation occurred at redshifts between z~1-2. The physical processes responsible for the subsequent demise of the faint blue galaxy population remains unclear. Considerable progress will be possible when the evolutionary trends can be monitored in the context of independent physical p...

  2. Space-efficient fiber ribbon composed of reduced-cladding single-mode fibers

    Science.gov (United States)

    Chang, J. H.; Bae, S. H.; Kim, Hoon; Ouh, C. H.; Jung, C. H.; Cho, H. S.; Chung, Y. C.

    2016-09-01

    We develop a space-efficient single-mode fiber (SMF) having a cladding diameter of only 82 μm. This SMF has the depressed-cladding index profile and its mode-field diameter, cutoff wavelength, and macro bending loss are designed to be similar to those of the conventional step-index SMF. We fabricate this reduced-cladding SMF and measure its optical and mechanical characteristics. The results show that this fiber satisfies major specifications of the ITU-T G.654 recommendations. We also fabricate a fiber ribbon by using twelve of these reduced-cladding SMFs. Compared to a commercial fiber ribbon made of twelve standard SMFs having 125-μm cladding diameter, this fiber ribbon can improve the spatial efficiency by ∼75%.

  3. Magnetic characterization of Fe-Al-B amorphous ribbons obtained by the melt spinning technique

    Directory of Open Access Journals (Sweden)

    Crespo R.D.

    2011-05-01

    Full Text Available The magnetic properties of a new amorphous material obtained by melt spinning technique is presented. The composition of the ribbon is Fe72Al14B14. The bulk hysteresis loops indicates that this ribbon is a soft magnetic material with a magnetic anisotropy along the longitudinal direction of the ribbon and an anisotropy constant of 1860 Jm-3. The value of the anisotropy is explained on the basis of the formation of directional order. The saturation magnetization results 1.12 T and the coercive field 18 Am-1. The surface magnetic properties show that the magnetic anisotropy is higher in the wheel-surface than in the air-surface. This result is explained considering the residual stress distribution in this kind of materials.

  4. Self-organised formation of nanotubes from graphene ribbons. A molecular dynamics study

    Science.gov (United States)

    Fülep, Dávid; Zsoldos, Ibolya; László, István

    2016-10-01

    The conditions for self-organised formations of carbon nanotubes from two parallel graphene ribbons were studied in a density functional adjusted tight binding molecular dynamics simulation. We have found that the seemingly trivial process is significantly limited by the thermal motion of the carbon atoms. There are further difficulties as well, primarily the unfavourable position of the atoms at the edges of the zigzag graphene ribbons. In repeated molecular dynamics runs we analysed the conditions of perfect coalescences, the influence of the substrate and the impact of the zigzag graphene ribbon positions. We have obtained that contrary to the abovementioned unfavourable conditions perfect nanotube production can be obtained using substrates. As the positioning of the substrate can be made with piezoelectric devices, this can significantly help the experimental realisation of the nanotube formation as well.

  5. Effects of surface crystallization and oxidation in nanocrystalline FeNbCuSiB(P) ribbons

    Science.gov (United States)

    Butvinová, B.; Butvin, P.; Brzózka, K.; Kuzminski, M.; Maťko, I.; Švec, P., Sr.; Chromčíková, M.

    2017-02-01

    Si-poor Fe74Nb3Cu1Si8B14-xPx, (x=0, 3) nanocrystalline ribbon-form alloys often form surfaces, which exert in-plane force on underlying ribbon interior when nanocrystallized in even modest presence of oxygen. Mostly unwanted hard-ribbon-axis magnetic anisotropy is standard result. Essential sources of the surface-caused stress have been sought and influence of P instead of B substitution on this effect was studied too. Preferred surface crystallization (PSC) was found to be the major reason. However P substitution suppresses PSC and promotes Fe-oxide formation, which eases the stress, softens the surfaces and provides different annealing evolution of surface properties.

  6. Perfect cubic texture, structure, and mechanical properties of nonmagnetic copper-based alloy ribbon substrates

    Science.gov (United States)

    Khlebnikova, Yu. V.; Rodionov, D. P.; Gervas'eva, I. V.; Egorova, L. Yu.; Suaridze, T. R.

    2015-03-01

    A sharp cubic texture is formed in a number of copper alloys subjected to cold deformation by rolling by 98.6-99% followed by recrystallization annealing, which opens up fresh opportunities for long thin ribbons made of these alloys to be used as substrates in the production of second-generation high- T c superconductor (2G HTSC) cables. The possibility of creating ternary alloys based on a binary Cu-30 at % Ni alloy with additional elements that harden its fcc matrix (iron, chromium) is shown. The measurements of the mechanical properties of textured ribbons made of these alloys demonstrate that their yield strength is higher than that of a textured ribbon made of pure copper by a factor of 2.5-4.5.

  7. H-alpha and hard X-ray development in two-ribbon flares

    Science.gov (United States)

    Dwivedi, B. N.; Hudson, H. S.; Kane, S. R.; Svestka, Z.

    1984-01-01

    Morphological features of two-ribbon flares have been studied, using simultaneous ISEE-3 hard X-ray records and high-resolution Big Bear H-alpha movies for more than 20 events. Long-lasting and complex hard X-ray bursts are almost invariably found associated with flares of the two-ribbon type. At least three events are found, namely March 31, 1979, April 10, 1980, and July 1, 1980, where the occurrence of individual spikes in hard X-ray radiation coincides with suddenly enhanced H-alpha emission covering the sunspot penumbra. There definitely exist important (greater than or equal to 1 B) two-ribbon flares without significant hard X-ray emission.

  8. Magnetic properties and coercivity mechanism of precipitation-hardened Gd-Co based ribbons

    Institute of Scientific and Technical Information of China (English)

    Rong Chuan-Bing; Zhang Jian; Du Xiao-Bo; Zhang Hong-Wei; Zhang Shao-Ying; Shen Bao-Gen

    2004-01-01

    Gd(Co0.88-xCuxFe0.09Zr0.03)z ribbons with x = 0.075 - 0.200 and z=6.4-7.7 have been prepared by a meltspinning technique. A cellular microstructure consisting of 2:17 cells surrounded by the 1:5 cell boundary phase is obtained after precipitation hardening. The dependence of room temperature coercivity on the heat treatment process suggests that the long-time isothermal aging is not helpful for the development of magnetic properties. Positive temperature coefficient of remanence from room temperature to about 673K is typical for all samples, while positive temperature coefficient of coercivity is obtained only in ribbons with low Cu content. The coercivity mechanism of the precipitation-hardened ribbons at different temperatures is also discussed.

  9. Evaluation of Dynamic Mechanical Loading as an Accelerated Test Method for Ribbon Fatigue

    Energy Technology Data Exchange (ETDEWEB)

    Bosco, Nick; Silverman, Timothy J.; Wohlgemuth, John; Kurtz, Sarah; Inoue, Masanao; Sakurai, Keiichiro; Shioda, Tsuyoshi; Zenkoh, Hirofumi; Hirota, Kusato; Miyashita, Masanori; Tadanori, Tanahashi; Suzuki, Soh; Chen, Yifeng; Verlinden, Pierre J.

    2014-12-31

    Dynamic Mechanical Loading (DML) of photovoltaic modules is explored as a route to quickly fatigue copper interconnect ribbons. Results indicate that most of the interconnect ribbons may be strained through module mechanical loading to a level that will result in failure in a few hundred to thousands of cycles. Considering the speed at which DML may be applied, this translates into a few hours of testing. To evaluate the equivalence of DML to thermal cycling, parallel tests were conducted with thermal cycling. Preliminary analysis suggests that one +/-1 kPa DML cycle is roughly equivalent to one standard accelerated thermal cycle and approximately 175 of these cycles are equivalent to a 25-year exposure in Golden Colorado for the mechanism of module ribbon fatigue.

  10. Electric gating induced bandgaps and enhanced Seebeck effect in zigzag bilayer graphene ribbons

    Science.gov (United States)

    Vu, Thanh-Tra; Tran, Van-Truong

    2016-08-01

    We theoretically investigate the effect of a transverse electric field generated by side gates and a vertical electric field generated by top/back gates on energy bands and transport properties of zigzag bilayer graphene ribbons (Bernal stacking). Using atomistic tight binding calculations and Green’s function formalism we demonstrate that a bandgap is opened when either field is applied and even enlarged under simultaneous influence of the two fields. Interestingly, although vertical electric fields are widely used to control the bandgap in bilayer graphene, here we show that transverse fields exhibit a more positive effect in terms of modulating a larger range of bandgap and retaining good electrical conductance. The Seebeck effect is also demonstrated to be enhanced strongly—by about 13 times for a zigzag bilayer graphene ribbon with 16 chain lines. These results may motivate new designs of devices made of bilayer graphene ribbons using electric gates.

  11. Evaluation of Dynamic Mechanical Loading as an Accelerated Test Method for Ribbon Fatigue: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Bosco, N.; Silverman, T. J.; Wohlgemuth, J.; Kurtz, S.; Inoue, M.; Sakurai, K.; Shinoda, T.; Zenkoh, H.; Hirota, K.; Miyashita, M.; Tadanori, T.; Suzuki, S.

    2015-04-07

    Dynamic Mechanical Loading (DML) of photovoltaic modules is explored as a route to quickly fatigue copper interconnect ribbons. Results indicate that most of the interconnect ribbons may be strained through module mechanical loading to a level that will result in failure in a few hundred to thousands of cycles. Considering the speed at which DML may be applied, this translates into a few hours o testing. To evaluate the equivalence of DML to thermal cycling, parallel tests were conducted with thermal cycling. Preliminary analysis suggests that one +/-1 kPa DML cycle is roughly equivalent to one standard accelerated thermal cycle and approximately 175 of these cycles are equivalent to a 25-year exposure in Golden Colorado for the mechanism of module ribbon fatigue.

  12. THE SURFACE STRUCTURAL AND MECHANICAL PROPERTIES OF THE AMORPHOUS CO22Y54AL24 RIBBON

    Directory of Open Access Journals (Sweden)

    Anna Bukowska

    2013-09-01

    Full Text Available The aim of this study was to manufacture amorphous Co22Y54Al24 alloy in a form of thin ribbons and to investigate their properties. The investigated ribbons were prepared by rapid solidification of molten metal on a rotating copper cylinder (melt-spinning. In order to obtain the material with amorphous structure, the cooling rate of the liquid alloy should vary in a range from 104 to 106 K/s. The microstructure studies were performed using X-ray diffractometery. The mechanical properties were investigated by metallographic studies, micro-hardness and tribological resistance tests moreover the surface roughness profile were analyzed. All studies were performed for two sides of tapes, since the differences in ribbons surface, related with manufacturing process, are clearly visible. The surface from the bottom (drum side was glossy and from the top side it was shiny.

  13. Floating Silicon Method single crystal ribbon - observations and proposed limit cycle theory

    Science.gov (United States)

    Kellerman, Peter; Kernan, Brian; Helenbrook, Brian T.; Sun, Dawei; Sinclair, Frank; Carlson, Frederick

    2016-10-01

    In the Floating Silicon Method (FSM), a single-crystal Si ribbon is grown while floating on the surface of a Si melt. In this paper, we describe the phenomenology of FSM, including the observation of approximately regularly spaced "facet lines" on the ribbon surface whose orientation aligns with (111) crystal planes. Sb demarcation experiments sectioned through the thickness of the ribbon reveal that the solid/melt interface consists of dual (111) planes and that the leading edge facet growth is saccadic in nature, rather than steady-state. To explain this behavior, we propose a heuristic solidification limit cycle theory, using a continuum level of description with anisotropic kinetics as developed by others, and generalizing the interface kinetics to include a roughening transition as well as a re-faceting mechanism that involves curvature and the Gibbs-Thomson effect.

  14. Design and performance of ultra-high-density optical fiber cable with rollable optical fiber ribbons

    Science.gov (United States)

    Hogari, Kazuo; Yamada, Yusuke; Toge, Kunihiro

    2010-08-01

    This paper proposes a novel ultra-high-density optical fiber cable that employs rollable optical fiber ribbons. The cable has great advantages in terms of cable weight and diameter, and fiber splicing workability. Moreover, it will be easy to install in a small space in underground ducts and on residential and business premises. The structural design of the rollable optical fiber ribbon is evaluated theoretically and experimentally, and an optimum adhesion pitch P in the longitudinal direction is obtained. In addition, we examined the performance of ultra-high-density cables with a small diameter that employ rollable optical fiber ribbons and bending-loss insensitive optical fibers. The transmission, mechanical and mid-span access performance of these cables was confirmed to be excellent.

  15. Edge plasmons and cut-off behavior of graphene nano-ribbon waveguides

    Science.gov (United States)

    Hou, Haowen; Teng, Jinghua; Palacios, Tomás; Chua, Soojin

    2016-07-01

    Graphene nano-ribbon waveguides with ultra-short plasmon wavelength are a promising candidate for nanoscale photonic applications. Graphene edge plasmons are the fundamental and lowest losses mode. Through finite element method, edge plasmons show large effective refractive index and strong field confinement on nanoscale ribbons. The edge plasmons follow a k1/2 dispersion relation. The wavelengths of the edge plasmons and center plasmons differ by a fixed factor. The width of edge plasmon is inversely proportional to wave vector of edge plasmon kedge. Edge defects associate with graphene nano-ribbon induce extra losses and reduce the propagation length. Cut-off width of edge plasmons reduces with increasing frequency. Cut-off width of center plasmon is enlarged by edge component but the enlargement effect diminishing with the increase of kedge. The results are important for the application of graphene plasmon towards ultra-compact photonic devices.

  16. Excitation of surface plasmon polaritons by electron beam with graphene ribbon arrays

    Science.gov (United States)

    Liu, Yong-Qiang; Liu, Pu-Kun

    2017-03-01

    Graphene has emerged as an alternative material to support surface plasmon polaritons (SPPs) with its excellent properties such as the tight electromagnetic field localization, low dissipative loss, and versatile tunability. Thus, graphene surface plasmon polaritons (GSPs) provide an exciting platform to develop a series of novel devices and systems from the optical band to the terahertz (THz) band. In this paper, theoretical and simulated studies about the excitation of SPPs by an injected electron beam with periodic graphene ribbon arrays deposited on a dielectric medium are presented. The analytical dispersion expression of the GSP mode on the graphene ribbon arrays is obtained by using a modal expansion method along with periodic boundary conditions in the structure. With this result, the dispersion relation, propagation loss, and field pattern of the propagating GSPs for both periodic graphene microribbon arrays and the complete graphene sheet are investigated and analyzed in the THz band. It is shown that the electromagnetic field with a better concentration on the interface can be realized with graphene ribbon arrays compared with the graphene sheet for a given frequency. Besides, the excitation of GSPs by an injected electron beam with graphene ribbon arrays is modeled and implemented by the particle-in-cell simulation based on the finite difference time domain algorithm. GSPs can be excited effectively when the dispersion line of the electron beam and SPPs on the graphene ribbon arrays is matched with each other well. Besides, the dependences of output power on electron beam parameters such as the distance of the electron beam above the graphene ribbon surface and beam voltage are studied and analyzed. Finally, the tunability of graphene conductivity via biased voltage with a ground metal is considered and the tunable excitation of GSPs on the structure with biased drive voltage by the injected electron beam is also realized. The present work can find a

  17. Calmodulin enhances ribbon replenishment and shapes filtering of synaptic transmission by cone photoreceptors.

    Science.gov (United States)

    Van Hook, Matthew J; Parmelee, Caitlyn M; Chen, Minghui; Cork, Karlene M; Curto, Carina; Thoreson, Wallace B

    2014-11-01

    At the first synapse in the vertebrate visual pathway, light-evoked changes in photoreceptor membrane potential alter the rate of glutamate release onto second-order retinal neurons. This process depends on the synaptic ribbon, a specialized structure found at various sensory synapses, to provide a supply of primed vesicles for release. Calcium (Ca(2+)) accelerates the replenishment of vesicles at cone ribbon synapses, but the mechanisms underlying this acceleration and its functional implications for vision are unknown. We studied vesicle replenishment using paired whole-cell recordings of cones and postsynaptic neurons in tiger salamander retinas and found that it involves two kinetic mechanisms, the faster of which was diminished by calmodulin (CaM) inhibitors. We developed an analytical model that can be applied to both conventional and ribbon synapses and showed that vesicle resupply is limited by a simple time constant, τ = 1/(Dρδs), where D is the vesicle diffusion coefficient, δ is the vesicle diameter, ρ is the vesicle density, and s is the probability of vesicle attachment. The combination of electrophysiological measurements, modeling, and total internal reflection fluorescence microscopy of single synaptic vesicles suggested that CaM speeds replenishment by enhancing vesicle attachment to the ribbon. Using electroretinogram and whole-cell recordings of light responses, we found that enhanced replenishment improves the ability of cone synapses to signal darkness after brief flashes of light and enhances the amplitude of responses to higher-frequency stimuli. By accelerating the resupply of vesicles to the ribbon, CaM extends the temporal range of synaptic transmission, allowing cones to transmit higher-frequency visual information to downstream neurons. Thus, the ability of the visual system to encode time-varying stimuli is shaped by the dynamics of vesicle replenishment at photoreceptor synaptic ribbons.

  18. Texture of Nanocomposite Nd2Fe14B/α-Fe Melt Spun Ribbons

    Institute of Scientific and Technical Information of China (English)

    姜忠良; 陈秀云; 白飞明; 马春来; 朱静

    2004-01-01

    Highly textured nanocomposite Nd9Fe84.5Nb0.5B6 ribbons were obtained by rapid solidification at wheel speeds from 15 to 20 m·s-1.X-ray diffraction(XRD)shows that these ribbons are preferentially orientated with the c axis of Nd2Fe14B phase perpendicular to the surface of the ribbons.The texture of Nd2Fe14B phase on the free surface is stronger than that on the contact surface and decreases with increase of wheel speed.The texture of Nd2Fe14B phase seems to be caused by the preferential growth of the crystal nuclei favorable orientation with their c-axes along the temperature gradient during rapid solidification,which can be explained by a growth circular cone(GCC).The intensity of the anisotropy can be expressed by the magnitude of the cone generating angle.The supercooling velocity and wheel speed will influence the cone generating angle,which in turn influences the anisotropy.The remanence and maximum energy product in the direction perpendicular to the ribbon surface is much higher than that in the direction parallel with the ribbon surface.High remanence and maximum energy product can be obtained in the direction perpendicular to the ribbon surface.The texture of Nd2Fe14B phase decreases gradually after annealing above 600 ℃,which is mainly attributed to the precipitation of new α-Fe from Nd2Fe14B phase with super-saturated Fe.Decreasing the annealing temperature or reducing the annealing time is beneficial for preserving the anisotropy of Nd2Fe14B phase after annealing.

  19. Optical and mechanical properties of glass fiber and ribbon reinforced poly(methyl methacrylate) composites

    Science.gov (United States)

    Barr, John Matthew

    Composites with excellent optical clarity have been fabricated by matching the refractive index of the glass fiber reinforcement to that of the polymer matrix. Refractive index mismatch, resulting from temperature changes, leads to degradation of optical clarity in fiber composites due to light impinging upon the fiber/matrix interface at oblique angles of incidence. The plane parallel surfaces of glass ribbon reinforcement minimize incidence at oblique angles, thereby reducing the sensitivity to refractive index mismatch. Optical data show that the use of ribbons in place of fibers increases the temperature range over which these composites retain good optical clarity by more than five times. A Monte Carlo type simulation of optical transmission of fiber reinforced composites has been developed. Temperature dependent optical transmission of glass fiber and ribbon reinforced composites was measured using a He/Ne laser and a detection assembly with an acceptance angle of 0.15sp°. Good agreement was observed between the measured transmission data and the calculations from the computer model. The computer model was used to predict achievable optical transmission in hypothetical fiber and ribbon composites with varying dn/dT and glass content. Results indicate that ribbon reinforced composites have the potential for nearly temperature independent optical clarity. Flexural strength of glass fiber and ribbon reinforced composites was calculated from 3-point bend data on specimens with a neat PMMA core and composite veneer on the surfaces. Veneer strength was 40 to 50% higher than that of neat PMMA. A hypothetical quasi-isotropic veneered composite was designed using lamination theory. For equivalent load bearing capacity beams, the mass of the composite is 16 and 70% less than neat PMMA and fused silica, respectively.

  20. Observations of an X-shaped Ribbon Flare in the Sun and Its Three-dimensional Magnetic Reconnection

    Science.gov (United States)

    Li, Y.; Qiu, J.; Longcope, D. W.; Ding, M. D.; Yang, K.

    2016-05-01

    We report evolution of an atypical X-shaped flare ribbon that provides novel observational evidence of three-dimensional (3D) magnetic reconnection at a separator. The flare occurred on 2014 November 9. High-resolution slit-jaw 1330 Å images from the Interface Region Imaging Spectrograph reveal four chromospheric flare ribbons that converge and form an X-shape. Flare brightening in the upper chromosphere spreads along the ribbons toward the center of the “X” (the X-point), and then spreads outward in a direction more perpendicular to the ribbons. These four ribbons are located in a quadrupolar magnetic field. Reconstruction of magnetic topology in the active region suggests the presence of a separator connecting to the X-point outlined by the ribbons. The inward motion of flare ribbons in the early stage therefore indicates 3D magnetic reconnection between two sets of non-coplanar loops that approach laterally, and reconnection proceeds downward along a section of vertical current sheet. Coronal loops are also observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory confirming the reconnection morphology illustrated by ribbon evolution.

  1. Ribbon thickness dependence of the Magnetic Alloy core characteristics in the accelerating frequency region of the J-PARC synchrotrons

    Science.gov (United States)

    Nomura, M.; Shimada, T.; Tamura, F.; Yamamoto, M.; Hara, K.; Hasegawa, K.; Ohmori, C.; Takata, K.; Toda, M.; Yoshii, M.; Schnase, A.

    2014-06-01

    We employ Magnetic Alloy (MA) core loaded RF cavities for the J-PARC synchrotrons to achieve a high field gradient. The MA core has a laminated structure of 18 μm thick ribbon layers. We have been developing high shunt impedance MA cores to prepare for an increase of beam power. At low frequencies, it is well known that the eddy current loss in the ribbon is proportional to the square of the ribbon thickness. The MA core shunt impedance can be increased by using thinner ribbons. On the other hand, at high frequencies, the MA core magnetic characteristics are largely different from low frequencies. Using thinner ribbons might be effective to increase the MA core shunt impedance in the accelerating frequency region of the J-PARC synchrotrons. We reviewed the theoretical calculations of the ribbon thickness dependence of the MA core magnetic characteristics and we derived the ribbon thickness dependence from measured data. The measured data show that the MA core shunt impedance is inversely proportional to the ribbon thickness in the accelerating frequency region of the J-PARC synchrotrons, which is consistent with our calculations.

  2. 75 FR 41808 - Narrow Woven Ribbons With Woven Selvedge From the People's Republic of China: Final Determination...

    Science.gov (United States)

    2010-07-19

    .... Narrow woven ribbons subject to the investigation may: Also include natural or other non-man-made fibers... packaging containing non-subject merchandise; (11) Narrow woven ribbon that is (a) affixed to non-subject merchandise as a working component of such non-subject merchandise, such as where narrow woven...

  3. 75 FR 41801 - Narrow Woven Ribbons with Woven Selvedge from the People's Republic of China: Final Affirmative...

    Science.gov (United States)

    2010-07-19

    .... Narrow woven ribbons subject to the investigation may: also include natural or other non-man-made fibers... packaging containing non-subject merchandise; (11) narrow woven ribbon that is (a) affixed to non-subject merchandise as a working component of such non-subject merchandise, such as where narrow woven...

  4. 75 FR 53642 - Narrow Woven Ribbons With Woven Selvedge From the People's Republic of China: Countervailing Duty...

    Science.gov (United States)

    2010-09-01

    ... natural or other non-man-made fibers; Be of any color, style, pattern, or weave construction, including... woven ribbon affixed (including by tying) as a decorative detail to non-subject merchandise, such as a... decorative detail to packaging containing non-subject merchandise; (11) Narrow woven ribbon that is...

  5. 77 FR 47363 - Narrow Woven Ribbons With Woven Selvedge From the People's Republic of China: Preliminary Results...

    Science.gov (United States)

    2012-08-08

    ... non-man-made fibers; Be of any color, style, pattern, or weave construction, including but not limited...) Narrow woven ribbon affixed (including by tying) as a decorative detail to non-subject merchandise, such... decorative detail to packaging containing non-subject merchandise; (11) Narrow woven ribbon that is...

  6. Influence of stresses on martensitic transformation in ferromagnetic shape memory Ni50Mn19Fe6Ga25 ribbons

    Institute of Scientific and Technical Information of China (English)

    MENG Fanbin; LI Yangxian; LIU Heyan; QU Jingping; LIU Zhuhong; CHEN Jinglan; WU Guangheng

    2004-01-01

    The influence of stresses on martensitic transformation in Nis0Mn19Fe6Ga25 melt-spun ribbons was studied. X-ray diffraction examination shows that the ribbon has a pure cubic L21 phase at room temperature and that the ribbon surface exhibits [100] preferentially oriented texture, while the [110] axis is about 45° tilted from the normal of the ribbon. By calculating the d spacing at different angles with the length direction of the ribbon, the tension was observed. It was found that the direction of the stress was along [010] direction of the oriented textured grains. During cooling, there is no obvious structural transition observed in as-spun ribbons. However, when the ribbons were annealed at 900 K for 24 h, the tension along [010] direction disappeared and the structural transition from cubic to tetragonal occurred obviously during cooling. It indicates that it is the tension along [010] direction to suppress the martensitic transformation in the as-spun ribbons.

  7. Microindentation as a perspective method for determination of mechanical properties of ribbon metallic glasses

    Institute of Scientific and Technical Information of China (English)

    Victor; A.; Feodorov; Inga; Y.; Permyakova; Andrey; N.; Kapustin

    2005-01-01

    Conditions of gauging of true microhardness of thin ribbons metallic glasses (MG) with the count of their depth are established. For the first time the method of a indentation was approved for an assessment of crack resistance of MG. The behavior of parameterKIc is found in a interval of temperature of viscous-brittle transition down to the beginning of volumetric crystallization of MG. The estimation method of temperature of viscous - brittle transition is offered at the microindentation of annealing ribbon on an elastic substrate.

  8. Giant magnetostriction in Tb-doped Fe83Ga17 melt-spun ribbons

    OpenAIRE

    Wei WU; Liu, Jinghua; Jiang, Chengbao; Xu, Huibin

    2013-01-01

    Giant magnetostriction is achieved in the slightly Tb-doped Fe83Ga17 melt-spun ribbons. The tested average perpendicular magnetostriction is -886 ppm along the melt-spun ribbon direction in the Fe82.89Ga16.88Tb0.23 alloy. The calculated parallel magnetostriction is 1772 ppm, more than 4 times as large as that of binary Fe83Ga17 alloy. The enhanced magnetostriction should be attributed to a small amount of Tb solution into the A2 matrix phase during rapid solidification. The localized strong m...

  9. Giant Magnetoimpedance Effect in Surface Modified CoFeMoSiB Amorphous Ribbons

    Institute of Scientific and Technical Information of China (English)

    M. A. Cerdeira; G. V. Kurlyandskaya; A. Fernandez; M. Tejedor; H. Garcia-Miquel

    2003-01-01

    Thin magnetic Fe layers in thickness of 10-240 nm were deposited onto a wheel surface of CoFeMoSiB amorphous ribbons to check our concept of a new type of heterogeneous magnetoimpedancematerials formed by two different magnetic parts. The presence of an additional iron layer modifies the magnetoimpedance response of the composite material and leads to increase of the magnetoimpedance ratio from 330 to 345% at a frequency of 3.5MHz.Two possible mechanisms are discussed for explanation to the observed behaviour. Modification of the surface properties of the amorphous ribbons may have certain potential for techmological applications.

  10. Overexpression of guanylate cyclase activating protein 2 in rod photoreceptors in vivo leads to morphological changes at the synaptic ribbon.

    Directory of Open Access Journals (Sweden)

    Natalia López-del Hoyo

    Full Text Available Guanylate cyclase activating proteins are EF-hand containing proteins that confer calcium sensitivity to retinal guanylate cyclase at the outer segment discs of photoreceptor cells. By making the rate of cGMP synthesis dependent on the free intracellular calcium levels set by illumination, GCAPs play a fundamental role in the recovery of the light response and light adaptation. The main isoforms GCAP1 and GCAP2 also localize to the synaptic terminal, where their function is not known. Based on the reported interaction of GCAP2 with Ribeye, the major component of synaptic ribbons, it was proposed that GCAP2 could mediate the synaptic ribbon dynamic changes that happen in response to light. We here present a thorough ultrastructural analysis of rod synaptic terminals in loss-of-function (GCAP1/GCAP2 double knockout and gain-of-function (transgenic overexpression mouse models of GCAP2. Rod synaptic ribbons in GCAPs-/- mice did not differ from wildtype ribbons when mice were raised in constant darkness, indicating that GCAPs are not required for ribbon early assembly or maturation. Transgenic overexpression of GCAP2 in rods led to a shortening of synaptic ribbons, and to a higher than normal percentage of club-shaped and spherical ribbon morphologies. Restoration of GCAP2 expression in the GCAPs-/- background (GCAP2 expression in the absence of endogenous GCAP1 had the striking result of shortening ribbon length to a much higher degree than overexpression of GCAP2 in the wildtype background, as well as reducing the thickness of the outer plexiform layer without affecting the number of rod photoreceptor cells. These results indicate that preservation of the GCAP1 to GCAP2 relative levels is relevant for maintaining the integrity of the synaptic terminal. Our demonstration of GCAP2 immunolocalization at synaptic ribbons at the ultrastructural level would support a role of GCAPs at mediating the effect of light on morphological remodeling changes of

  11. Natural Blue Food Colour

    DEFF Research Database (Denmark)

    Roda-Serrat, Maria Cinta

    2017-01-01

    the presence of the chromophore phycocyanobilin (PCB), a covalently attached linear tetrapyrrole. The applications of phycocyanins as food colorants are however limited, as they show poor stability in certain conditions of pH, light and temperature. Cleavage of PCB from the protein followed by careful product...... decreased. PCB was also found to be more sensitive to pH than phycocyanin. Regarding the stability with time, PCB showed a similar stability at pH 3, and worse at pH 5 and pH 7. The change from blue to green colour in acid conditions was attributed to protonation of the chromophore. However, the effect...

  12. Flare Ribbons In The Early Phase Of An SDO Flare: Emission Measure And Energetics

    Science.gov (United States)

    Fletcher, Lyndsay; Hannah, I. G.; Hudson, H. S.; Innes, D. E.

    2012-05-01

    We report on the M1.0 flare of 7th August 2010, which displayed extended early phase chromospheric ribbons, well observed by SDO/AIA and RHESSI. Most large flares saturate rapidly in the high-temperature AIA channels, however this event could be followed in unsaturated AIA images for ten minutes in the build-up to and first few minutes of the impulsive phase. Analysis of GOES, RHESSI and SDO/AIA demonstrates the presence of high temperature ( 10MK), compact plasma volumes in the chromospheric flare ribbons, with a column emission measure of on average 3-7 x 1028 cm-5. We construct a time-resolved energy budget for the ribbon plasma, including also SDO/EVE data, and discuss the implications of the observed ribbon properties for flare energisation. This work was supported by the UK’s Science and Technology Facilities Council (ST/1001801), and by the European Commission through the FP7 HESPE project (FP7-2010-SPACE-263086).

  13. VAMP4 is required to maintain the ribbon structure of the Golgi apparatus.

    Science.gov (United States)

    Shitara, Akiko; Shibui, Toru; Okayama, Miki; Arakawa, Toshiya; Mizoguchi, Itaru; Sakakura, Yasunori; Shakakura, Yasunori; Takuma, Taishin

    2013-08-01

    The Golgi apparatus forms a twisted ribbon-like network in the juxtanuclear region of vertebrate cells. Vesicle-associated membrane protein 4 (VAMP4), a v-SNARE protein expressed exclusively in the vertebrate trans-Golgi network (TGN), plays a role in retrograde trafficking from the early endosome to the TGN, although its precise function within the Golgi apparatus remains unclear. To determine whether VAMP4 plays a functional role in maintaining the structure of the Golgi apparatus, we depleted VAMP4 gene expression using RNA interference technology. Depletion of VAMP4 from HeLa cells led to fragmentation of the Golgi ribbon. These fragments were not uniformly distributed throughout the cytoplasm, but remained in the juxtanuclear area. Electron microscopy and immunohistochemistry showed that in the absence of VAMP4, the length of the Golgi stack was shortened, but Golgi stacking was normal. Anterograde trafficking was not impaired in VAMP4-depleted cells, which contained intact microtubule arrays. Depletion of the cognate SNARE partners of VAMP4, syntaxin 6, syntaxin 16, and Vti1a also disrupted the Golgi ribbon structure. Our findings suggested that the maintenance of Golgi ribbon structure requires normal retrograde trafficking from the early endosome to the TGN, which is likely to be mediated by the formation of VAMP4-containing SNARE complexes.

  14. 77 FR 32938 - Narrow Woven Ribbons With Woven Selvedge From Taiwan: Preliminary Results of Antidumping Duty...

    Science.gov (United States)

    2012-06-04

    ... the manufacture of typewriter or printer ribbons; (5) Narrow woven labels and apparel tapes, cut-to... States, 337 F.3d 1373, 1382-83 (Fed. Cir. 2003) (Nippon). We preliminarily find that Hubschercorp did not... respect to this company. See Nippon, 337 F.3d at 1382-83. Selection of the AFA Rate Section 776(b) of...

  15. Nanocrystallization in Co67Cr7Fe4Si8B14 Amorphous Alloy Ribbons

    Directory of Open Access Journals (Sweden)

    Zahra Jamili-Shirvan

    2013-12-01

    Full Text Available The nanocrystallization of Co67Fe4Cr7Si8B14 amorphous ribbons which prepared by planar flow melt spinning process (PFMS was investigated. Crystallization of the ribbons was studied by differential thermal analysis (DTA, X-ray diffraction (XRD and transmission electron microscopy (TEM. The DTA result of amorphous ribbon at heating rate of 10˚C/min showedoccurrence of phase transitions in two stages. The ribbons were isothermally annealed for 30 minutes in argon atmosphere at different temperatures between 300 and 650ºC with 25ºC steps. The magnetic properties of annealed samples were measured using a vibrating sample magnetometer (VSM. The VSM results revealed that optimum soft magnetic properties occurred at 400ºC. XRD patterns showed that the samples isothermally annealed up to 450ºC were amorphous, while TEM results at 400ºC indicated 7-8 nm mean size nanocrytallites in amorphous matrix and size of the nanocrystallites increased by increasing temperature. Also by X-ray diffraction pattern, precipitation of different phases at higher temperatures confirmed.

  16. ATRF Ribbon-Cutting Ceremony Coincides with Chamber of Commerce Centennial Gala | Poster

    Science.gov (United States)

    By Frank Blanchard, Staff Writer U.S. Rep. Roscoe Bartlett, NCI Deputy Director for Management John Czajkowski, and SAIC Corporate Chief Executive Officer (CEO) John Jumper were joined by representatives of the Frederick County Chamber of Commerce in cutting the ribbon for the National Cancer Institute’s Advanced Technology Research Facility (ATRF).

  17. Highly sensitive giant magnetoimpedance in a solenoid containing FeCo-based ribbon

    Institute of Scientific and Technical Information of China (English)

    Fang Yun-Zhang; Xu Qi-Ming; Zheng Jin-Ju; Wu Feng-Min; Ye Hui-Qun; Si Jian-Xiao; Zheng Jian-Long; Fan Xiao-Zhen; Yang Xiao-Hong

    2012-01-01

    The highly sensitive giant magneto-impedance effect in a solenoid containing a magnetic core of Fe36Co36Nb4Si4.sB19.2 (FeCo-based) ribbon under a weak magnetic field (WMF) is presented in this paper. The FeCo-based amorphous ribbon is prepared by single roller quenching and annealed with Joule heat in a flowing nitrogen atmosphere.The giant magnetoimpedance effect in solenoid (GMIES) profiles are measured with an HP4294A impedance analyzer.The result shows that the GMIES responds to the WMF sensitively (as high as 1580 %/A·m-l).The high sensitivity can be obtained in a moderate narrow range of annealing current density (30-34 A/mm2) and closely depends on the driven current frequency.The highest sensitivity (1580 %/A.m-1) is obtained when the FeCobased amorphous ribbon is annealed at 32 A/mm2 for 10 min and then driven with an alterning current (AC) at the frequency of 350 kHz.The highly sensitive GMIES under the WMF may result from the multiple magnetic-anisotropic structure,which is induced by the temperature gradient produced during Joule-heating the ribbon.

  18. Treatment with Piribedil and Memantine Reduces Noise-Induced Loss of Inner Hair Cell Synaptic Ribbons

    Science.gov (United States)

    Altschuler, Richard A.; Wys, Noel; Prieskorn, Diane; Martin, Cathy; DeRemer, Susan; Bledsoe, Sanford; Miller, Josef M.

    2016-01-01

    Noise overstimulation can induce loss of synaptic ribbons associated with loss of Inner Hair Cell – Auditory Nerve synaptic connections. This study examined if systemic administration of Piribedil, a dopamine agonist that reduces the sound evoked auditory nerve compound action potential and/or Memantine, an NMDA receptor open channel blocker, would reduce noise-induced loss of Inner Hair Cell ribbons. Rats received systemic Memantine and/or Piribedil for 3 days before and 3 days after a 3 hour 4 kHz octave band noise at 117 dB (SPL). At 21 days following the noise there was a 26% and 38% loss of synaptic ribbons in regions 5.5 and 6.5 mm from apex, respectively, elevations in 4-, 8- and 20 kHz tonal ABR thresholds and reduced dynamic output at higher intensities of stimulation. Combined treatment with Piribedil and Memantine produced a significant reduction in the noise-induced loss of ribbons in both regions and changes in ABR sensitivity and dynamic responsiveness. Piribedil alone gave significant reduction in only the 5.5 mm region and Memantine alone did not reach significance in either region. Results identify treatments that could prevent the hearing loss and hearing disorders that result from noise-induced loss of Inner Hair Cell – Auditory Nerve synaptic connections. PMID:27686418

  19. Chromospheric Condensation and Quasi-periodic Pulsations in a Circular-ribbon Flare

    CERN Document Server

    Zhang, Q M; Ning, Z J

    2016-01-01

    In this paper, we report our multiwavelength observations of the C3.1 circular-ribbon flare SOL2015-10-16T10:20 in AR 12434. The flare consisted of a circular flare ribbon (CFR), an inner flare ribbon (IFR) inside, and a pair of short parallel flare ribbons (PFRs). During the impulsive phase of the flare, "two-step" raster observations of \\textit{IRIS} with a cadence of 6 s and an exposure time of 2 s show plasma downflow at the CFR in the Si {\\sc iv} $\\lambda$1402.77 line, suggesting chromospheric condensation. The downflow speeds first increased rapidly from a few km s$^{-1}$ to the peak values of 45$-$52 km s$^{-1}$, before decreasing gradually to the initial levels. The decay timescales of condensation were 3$-$4 minutes, indicating ongoing magnetic reconnection. Interestingly, the downflow speeds are positively correlated with logarithm of the Si {\\sc iv} line intensity and time derivative of the \\textit{GOES} soft X-ray (SXR) flux in 1$-$8 {\\AA}. The radio dynamic spectra are characterized by a type \\Rm...

  20. Fracture of FeNiB-NiP amorphous bilayer ribbon

    NARCIS (Netherlands)

    Miskuf, J; Csach, K; Ocelik, [No Value; Duhaj, P; Ocelik, Vaclav

    1997-01-01

    The Study of failure surfaces of amorphous bimetal ribbons Fe40Ni40B20-Ni82P18 failed during tensile testing in the as-quenched and relaxed states (anneaIed at 250 degrees C) is presented. Two different fracture morphologies are observed on failed as-quenched samples: (i) near the maximum shear stre

  1. The Relation between Solar Eruption Topologies and Observed Flare Features I: Flare Ribbons

    CERN Document Server

    Savcheva, A; McKillop, S; McCauley, P; Hanson, E; Su, Y; Werner, E; DeLuca, E E

    2015-01-01

    In this paper we present a topological magnetic field investigation of seven two-ribbon flares in sigmoidal active regions observed with Hinode, STEREO, and SDO. We first derive the 3D coronal magnetic field structure of all regions using marginally unstable 3D coronal magnetic field models created with the flux rope insertion method. The unstable models have been shown to be a good model of the flaring magnetic field configurations. Regions are selected based on their pre-flare configurations along with the appearance and observational coverage of flare ribbons, and the model is constrained using pre-flare features observed in extreme ultraviolet and X-ray passbands. We perform a topology analysis of the models by computing the squashing factor, Q, in order to determine the locations of prominent quasi-separatrix layers (QSLs). QSLs from these maps are compared to flare ribbons at their full extents. We show that in all cases the straight segments of the two J-shaped ribbons are matched very well by the flux...

  2. The electro-mechanical responses of suspended graphene ribbons for electrostatic discharge applications

    Science.gov (United States)

    Zhang, Wei; Ma, Rui; Chen, Qi; Xia, Ming; Ng, Jimmy; Wang, Albert; Xie, Ya-Hong

    2016-04-01

    This work presents a suspended graphene ribbon device for electrostatic discharge (ESD) applications. The device structure was proposed and fabricated after careful design considerations. Compared to the conventional ESD devices such as diodes, bipolar junction transistors, and metal-oxide-semiconductor field effect transistors, the proposed device structure is believed to render several advantages including zero leakage, low parasitic effects, fast response, and high critical current density. A process flow was developed for higher yield and reliability of the suspended graphene ribbons. Direct current (DC) and transmission-line pulse (TLP) measurements were carried out to investigate the switching behavior of the device, which is crucial for ESD operation. DC measurements with a different configuration were used to assess the mechanical shape evolution of the graphene ribbon upon biasing. Finite Element Simulations were conducted and agreed well with the experimental results. Furthermore, the current carrying capability of non-suspended graphene ribbons was tested using TLP. It was found that the critical current density of graphene is higher than that of copper wires widely used as interconnects in integrated circuits (ICs).

  3. Spectroscopic observations of evolving flare ribbon substructure suggesting origin in current sheet waves

    Science.gov (United States)

    Brannon, Sean R.; Longcope, Dana; Qiu, Jiong

    2015-04-01

    A flare ribbon is the chromospheric image of reconnection at a coronal current sheet. The dynamics and structure of the ribbon can thus reveal properties of the current sheet, including motion of the reconnecting flare loops. We present imaging and spectroscopic observations from the Interface Region Imaging Spectrograph (IRIS) of the evolution of a flare ribbon at high spatial resolution and time cadence. These reveal small-scale substructure in the ribbon, which manifest as oscillations in both position and Doppler velocities. We consider various alternative explanations for these oscillations, including modulation of chromospheric evaporation flows. Among these we find the best support for some form of elliptical wave localized to the coronal current sheet, such as a tearing mode or Kelvin-Helmholtz instability.IRIS is a NASA Small Explorer mission developed and operated by Lockheed Martin Solar and Astrophysics Laboratory. This work is supported by contract 8100002702 from Lockheed Martin to Montana State University, a Montana Space Grant Consortium fellowship, and by NASA through HSR.

  4. In vivo knockdown of Piccolino disrupts presynaptic ribbon morphology in mouse photoreceptor synapses

    Directory of Open Access Journals (Sweden)

    Hanna eRegus-Leidig

    2014-09-01

    Full Text Available Piccolo is the largest known cytomatrix protein at active zones of chemical synapses. A growing number of studies on conventional chemical synapses assign Piccolo a role in the recruitment and integration of molecules relevant for both endo- and exocytosis of synaptic vesicles, the dynamic assembly of presynaptic F-actin, as well as the proteostasis of presynaptic proteins, yet a direct function in the structural organization of the active zone has not been uncovered in part due to the expression of multiple alternatively spliced isoforms. We recently identified Piccolino, a Piccolo splice variant specifically expressed in sensory ribbon synapses of the eye and ear. Here we down regulated Piccolino in vivo via an adeno-associated virus-based RNA interference approach and explored the impact on the presynaptic structure of mouse photoreceptor ribbon synapses. Detailed immunocytochemical light and electron microscopical analysis of Piccolino knockdown in photoreceptors revealed a hitherto undescribed photoreceptor ribbon synaptic phenotype with striking morphological changes of synaptic ribbon ultrastructure.

  5. Reefing of Quarter Spherical Ribbon Parachutes used in the Ares I First Stage Deceleration Subsystem

    Science.gov (United States)

    Schmidt, Jason R.; McFadden, Peter G.

    2009-01-01

    Normalizing drop test reefed drag area for suspension line length with data from Wolf allows best match of test results with Knacke reefing ratio curve. Various sizes and porosities of quarter spherical ribbon parachutes were tested. All appear to fit the published reefing ratio curve-quarter spherical parachutes match.

  6. Adiabatic magnetocaloric effect in Ni50Mn35In15 ribbons

    Science.gov (United States)

    Álvarez-Alonso, P.; Aguilar-Ortiz, C. O.; Camarillo, J. P.; Salazar, D.; Flores-Zúñiga, H.; Chernenko, V. A.

    2016-11-01

    Heusler-type Ni-Mn-based metamagnetic shape memory alloys (MetaMSMAs) are promising candidates for magnetic refrigeration. To increase heat exchange rate and efficiency of cooling, the material should have a high surface/volume ratio. In this work, the typical Ni50Mn35In15 MetaMSMA was selected to fabricate thin ribbons by melt-spinning. The characteristic transformations of the ribbons were determined by calorimetry, X-ray diffraction, scanning electron microscopy and thermomagnetization measurements. The inverse and conventional magnetocaloric effects (MCEs) associated with the martensitic transformation (MT) and the ferromagnetic transition of the austenite (TCA), respectively, were measured directly by the adiabatic method (ΔTad) and indirectly by estimating the magnetic entropy change from magnetization measurements. It is found that the ribbons exhibit large values of ΔTad = -1.1 K at μ0ΔH = 1.9 T, in the vicinity of the MT temperature of 300 K for inverse MCE, and ΔTad = 2.3 K for conventional MCE at TCA = 309 K. This result strongly motivates further development of different MetaMSMA refrigerants shaped as ribbons.

  7. Magnetic and Crystalline Microstructures of Fe-Pt-B Nanocomposite Ribbons

    Institute of Scientific and Technical Information of China (English)

    FANG Yi-Kun; CHANG Cheng-Wu; CHANG Wen-Cheng; XIA Ai-Lin; CHEN Qiang; GE Hong-Liang; HAN Bao-Shan

    2005-01-01

    @@ We investigate magnetic and crystalline microstructures of melt-spun (Fe0.675Pt0.325 )100-xBx (x = 12, 14, 16, 18,20) nanocomposite ribbons after optimal thermal treatment using a magnetic force microscope. The magnetic microstructures are characterized by darker spots adjacent to brighter ones in a sub-micro scale and in random distribution. It is found that the strength of the exchange coupling interaction between the crystals in the 10-100 nm scale, implied by the maximum value (δM)max of the Henkel plot, could be roughly described by the ratio of the average width of the magnetic spots w to the average crystal size D for the ribbons. Moreover, we find that the intrinsic coercivity jHc of the ribbons is sensitive to their crystal sizes, and the smaller D, the higher jHc. Finally, by using roughness analysis, the curve of the root mean square values (δφ)rms of the phase shift of the magnetic force images versus the boron content x is obtained, which is qualitatively consistent with that of the magnetization σ12 koe of the ribbons versus x.

  8. The identification of a sensitizing component used in the manufacturing of an ink ribbon.

    Science.gov (United States)

    Anderson, Stacey E; Tapp, Loren; Durgam, Srinivas; Meade, B Jean; Jackson, Laurel G; Cohen, David E

    2012-01-01

    Skin diseases including dermatitis constitute ≈ 30% of all occupational illnesses, with a high incidence in the printing industry. An outbreak of contact dermatitis among employees at an ink ribbon manufacturing plant was investigated by scientists from the National Institute for Occupational Safety and Health (NIOSH). Employees in the process areas of the plant were exposed to numerous chemicals and many had experienced skin rashes, especially after the introduction of a new ink ribbon product. To identify the causative agent(s) of the occupational dermatitis, the murine local lymph node assay (LLNA) was used to identify the potential of the chemicals used in the manufacture of the ink ribbon to induce allergic contact dermatitis. Follow-up patch testing with the suspected allergens was conducted on exposed employees. Polyvinyl butyral, a chemical component used in the manufacture of the ink ribbon in question and other products, tested positive in the LLNA, with an EC3 of 3.6%, which identifies it as a potential sensitizer; however, no employees tested positive to this chemical during skin patch testing. This finding has implications beyond those described in this report because of occupational exposure to polyvinyl butyral outside of the printing industry.

  9. GMI effect in CuO coated Co-based amorphous ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Taysioglu, Asli Ayten [Department of Physics, Sciences and Arts Faculty, Uludag University, 16059 Gorukle, Bursa (Turkey); Peksoz, Ahmet, E-mail: peksoz@uludag.edu.t [Department of Physics, Sciences and Arts Faculty, Uludag University, 16059 Gorukle, Bursa (Turkey); Kaya, Yunus [Department of Chemistry, Sciences and Arts Faculty, Uludag University, 16059 Gorukle, Bursa (Turkey); Derebasi, Naim [Department of Physics, Sciences and Arts Faculty, Uludag University, 16059 Gorukle, Bursa (Turkey); Irez, Gazi [Department of Chemistry, Sciences and Arts Faculty, Uludag University, 16059 Gorukle, Bursa (Turkey); Kaynak, Gokay [Department of Physics, Sciences and Arts Faculty, Uludag University, 16059 Gorukle, Bursa (Turkey)

    2009-11-13

    A Copper oxide (CuO) film has been grown on a surface of Co-based amorphous ribbon using chemical successive ionic layer adsorption and reaction technique, at room temperature and atmosphere pressure. The influence of coating and width of ribbon on giant magneto impedance have been investigated over a frequency range from 0.1 to 3 MHz and under a static magnetic field between -8 and +8 kA/m. The results showed that Co-based amorphous ribbons, which are coated CuO film, have a significant effect on the magnitude and operation frequency for the giant magneto impedance effect as compared to the samples without coating. The highest giant magneto impedance effect was found to be 14.90 on 5 mm width coated ribbon, which is 60% higher than the sample without coating. A surface observation of these samples has been carried out by an atomic force microscope. The AFM images reveal the difference between surfaces of coated and as-cast sample.

  10. Short-range Ferromagnetism in Alloy Ribbons of Fe-Cr-Si-Nb-(Ag, Cu)

    DEFF Research Database (Denmark)

    Thanh, P. Q.; Hoa, N. Q.; Chau, N.;

    2014-01-01

    We have studied the magnetic properties of two amorphous alloy ribbons Fe72Cr6Si4Nb5B12Ag1 (FCSNB-Ag) and Fe72Cr6Si4Nb5B12Cu1 (FCSNB-Cu), prepared by using a melt-spinning technique. Magnetization (M) measurements for various temperatures (T) and magnetic fields (H) indicate that ferromagnetic...

  11. A route to uniaxially oriented ribbons of bacterial cellulose nanocrystals based on isomalt spun sacrificial template

    OpenAIRE

    2014-01-01

    We have carried out orientation of bacterial cellulose nanocrystals (BCNC) by implementing a process based on mechanical shearing BCNC dispersed in a viscous temporary isomalt glass. After the orientation, the isomalt matrix was selectively solubilized to afford uniaxially highly oriented BCNC ribbons as demonstrated by SEM and X-Ray studies. The 2D WAXS determined Herman's order parameter reached 0.85.

  12. The Ribbon Workers as Popular Educators: (Re)-Presenting the Colours of the Crusades

    Science.gov (United States)

    Lander, Dorothy A.

    2005-01-01

    The educational aim of this genealogical study of ribbon workers as popular educators is to expose activist and voluntary organisations, not only as generative sites of learning, but also as sites of habituated learning and stereotypical colour assumptions. This study urges popular educators and activists to reflect critically on the popular…

  13. Influence of structural parameters on magnetoresistive properties of CuFeNi melt spun ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Cazottes, S., E-mail: sophie.cazottes@etu.univ-rouen.fr [Groupe de Physique des Materiaux (GPM), Universite de Rouen, UMR CNRS 6634, Site Universitaire du Madrillet, Avenue de l' Universite, BP 12, 76801 Saint-Etienne du Rouvray Cedex (France); Danoix, F.; Fnidiki, A.; Lemarchand, D. [Groupe de Physique des Materiaux (GPM), Universite de Rouen, UMR CNRS 6634, Site Universitaire du Madrillet, Avenue de l' Universite, BP 12, 76801 Saint-Etienne du Rouvray Cedex (France); Baricco, M. [Dipartimento di Chimica IFM and NIS/INSTM, Universita' di Torino, Via P. Giuria 9, 10125 Torino (Italy)

    2009-04-15

    The microstructure of Cu{sub 80}Fe{sub 10}Ni{sub 10} (at%) granular ribbon was investigated by means of atom probe tomography (APT). A granular system is composed of magnetic precipitates embedded in a non-magnetic matrix. In this ribbon, the magnetic precipitates have a diameter smaller than 5 nm in the as-spun state, and their crystallographic structure is very similar to the one of the matrix, which makes it difficult to characterize them using conventional techniques. Those data are of great importance to understand the magnetic and the transport behaviour of these ribbons. Using atom probe tomography, a 3D reconstruction of the microstructure of the as-spun and annealed ribbons was achieved and a precise characterization of the compositions of the two phases and of the composition profile at interfaces was carried out. In the as-spun state the composition of the matrix is Cu{sub 89}Fe{sub 3}Ni{sub 8}, the one of the precipitates is Cu{sub 30}Fe{sub 40}Ni{sub 30}. Upon annealing, the precipitates get enriched in iron. After annealing at 600 {sup o}C for 24 h, the measured compositions are close to the one predicted by Thermocalc, with Cu{sub 94}Fe{sub 1}Ni{sub 5} for the matrix and Cu{sub 5}Fe{sub 64}Ni{sub 31} for the precipitates.

  14. Influence of structural parameters on magnetoresistive properties of CuFeNi melt spun ribbons.

    Science.gov (United States)

    Cazottes, S; Danoix, F; Fnidiki, A; Lemarchand, D; Baricco, M

    2009-04-01

    The microstructure of Cu(80)Fe(10)Ni(10) (at%) granular ribbon was investigated by means of atom probe tomography (APT). A granular system is composed of magnetic precipitates embedded in a non-magnetic matrix. In this ribbon, the magnetic precipitates have a diameter smaller than 5nm in the as-spun state, and their crystallographic structure is very similar to the one of the matrix, which makes it difficult to characterize them using conventional techniques. Those data are of great importance to understand the magnetic and the transport behaviour of these ribbons. Using atom probe tomography, a 3D reconstruction of the microstructure of the as-spun and annealed ribbons was achieved and a precise characterization of the compositions of the two phases and of the composition profile at interfaces was carried out. In the as-spun state the composition of the matrix is Cu(89)Fe(3)Ni(8), the one of the precipitates is Cu(30)Fe(40)Ni(30). Upon annealing, the precipitates get enriched in iron. After annealing at 600 degrees C for 24h, the measured compositions are close to the one predicted by Thermocalc, with Cu(94)Fe(1)Ni(5) for the matrix and Cu(5)Fe(64)Ni(31) for the precipitates.

  15. Evolution of the Topology, Electric Currents, and Ribbons during an X-class Flare

    Science.gov (United States)

    Savcheva, Antonia; Janvier, Miho; Pariat, Etienne

    2016-05-01

    The standard model for eruptive flares has in the past few years been extended to 3D. It predicts typical J-shaped photospheric footprints of the coronal current layer, forming at similar locations as the Quasi-Separatrix Layers (QSLs). We study the evolution of the photospheric traces of the current density and the flare ribbons observed with SDO. We aim at comparing their morphology and their time evolution, before and during the flare, with the topological features found in a magnetic field model. For this purpose we investigate the photospheric current evolution during the 6 Sep 2011 X-class flare occurring in AR11283 from observational data of the magnetic field obtained with HMI. This evolution is compared with that of the flare ribbons observed with AIA. We also compare the observed electric current density and the flare ribbon morphology with that of the QSLs computed from magnetic field models obtained from the the flux rope insertion method. Both the NLFFF and the unstable (eruptive) model show the presence of a fan-spine configuration of overlying field lines, due to the presence of a parasitic polarity, embedding in elongated flux rope that appears in the observations as two parts of a filament. The magnetofrictional evolution of the unstable model tells a consistent story of the filament eruption in which topology plays an important role. The photospheric QSL traces of the fan configuration appear as an elongated flare ribbon that encircles the J-shaped ribbons related to the filament ejection. The QSLs, evolved via a magnetofrictional method, also show similar morphology and evolution as both the current ribbons and the EUV flare ribbons obtained at several times during the flare. For the first time, we propose a combined analysis of the photospheric traces of an eruptive flare, in a complex topology, with direct measurements of electric currents and QSLs from observational data and a magnetic field model. The results obtained by two independent

  16. Postpartum Blues and Postpartum Depression

    Directory of Open Access Journals (Sweden)

    Erdem Ö et al.

    2009-09-01

    Full Text Available Postpartum blues which is seen during the postpartum period is a transient psychological state. Most of the mothers experience maternity blues in postpartum period. It remains usually unrecognized by the others. Some sensitive families can misattribute these feelings as depression. In this article, we tried to review the characteristics of maternity blues and its differences from depression. We defined depression and presented the incidence and diagnostic criteria, of major depression as well as the risk factors and clinic findings of postpartum depression. Thus, especially at primary care we aimed to prevent misdiagnosis of both maternity blues and depression

  17. Surface valence transformation during thermal activation and hydrogenation thermodynamics of Mg-Ni-Y melt-spun ribbons

    Science.gov (United States)

    Zhang, Tiebang; Song, Wenjie; Kou, Hongchao; Li, Jinshan

    2016-05-01

    In this work, phase compositions and chemical valence states on the surface and subsurface of Mg67Ni33-xYx (x = 0, 1, 3, 6) ribbons during thermal activation have been investigated by X-ray photoelectron spectroscopy (XPS). The results indicate that the surface contaminants of melt-spun ribbons are mainly MgO, NiO, Y2O3 and organics. The oxides/hydroxides of Mg67Ni33-xYx (x = 0, 1, 3, 6) melt-spun ribbons are removed from the surface during thermal activation. Surface chemical valence firstly transforms from oxidized state to the metallic one during thermal activation, which accounts for hydrogenation of Mg67Ni33-xYx melt-spun ribbons. Hydrogen absorption capacities of Mg67Ni33-xYx (x = 0, 1, 3, 6) melt-spun ribbons are enhanced with the increase of cycle numbers during thermal activation. Hydrogenation thermodynamics of activated Mg67Ni33-xYx (x = 0, 1, 3, 6) melt-spun ribbons have been also compared and correlated with the surface valence transformation. The obtained enthalpy of hydride formation is -55.5, -50.5, -46.9 and -48.6 kJ/mol for Mg67Ni33-xYx melt-spun ribbons with x = 0, 1, 3 and 6, respectively.

  18. Observations of an X-shaped Ribbon Flare in the Sun and Its Three-dimensional Magnetic Reconnection

    CERN Document Server

    Li, Y; Longcope, D W; Ding, M D; Yang, K

    2016-01-01

    We report evolution of an atypical X-shaped flare ribbon which provides novel observational evidence of three-dimensional (3D) magnetic reconnection at a separator. The flare occurred on 2014 November 9. High-resolution slit-jaw 1330 A images from the Interface Region Imaging Spectrograph reveal four chromospheric flare ribbons that converge and form an X-shape. Flare brightening in the upper chromosphere spreads along the ribbons toward the center of the "X" (the X-point), and then spreads outward in a direction more perpendicular to the ribbons. These four ribbons are located in a quadrupolar magnetic field. Reconstruction of magnetic topology in the active region suggests the presence of a separator connecting to the X-point outlined by the ribbons. The inward motion of flare ribbons in the early stage therefore indicates 3D magnetic reconnection between two sets of non-coplanar loops that approach laterally, and reconnection proceeds downward along a section of vertical current sheet. Coronal loops are al...

  19. A CIRCULAR-RIBBON SOLAR FLARE FOLLOWING AN ASYMMETRIC FILAMENT ERUPTION

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chang; Deng, Na; Lee, Jeongwoo; Wang, Haimin [Space Weather Research Laboratory, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982 (United States); Liu, Rui [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei 230026 (China); Pariat, Étienne [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universits, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, F-92190 Meudon (France); Wiegelmann, Thomas [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig Weg 3, D-37077 Göttingen (Germany); Liu, Yang [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305-4085 (United States); Kleint, Lucia, E-mail: chang.liu@njit.edu [University of Applied Sciences and Arts Northwestern Switzerland, Bahnhofstrasse 6, 5210 Windisch (Switzerland)

    2015-10-20

    The dynamic properties of flare ribbons and the often associated filament eruptions can provide crucial information on the flaring coronal magnetic field. This Letter analyzes the GOES-class X1.0 flare on 2014 March 29 (SOL2014-03-29T17:48), in which we found an asymmetric eruption of a sigmoidal filament and an ensuing circular flare ribbon. Initially both EUV images and a preflare nonlinear force-free field model show that the filament is embedded in magnetic fields with a fan-spine-like structure. In the first phase, which is defined by a weak but still increasing X-ray emission, the western portion of the sigmoidal filament arches upward and then remains quasi-static for about five minutes. The western fan-like and the outer spine-like fields display an ascending motion, and several associated ribbons begin to brighten. Also found is a bright EUV flow that streams down along the eastern fan-like field. In the second phase that includes the main peak of hard X-ray (HXR) emission, the filament erupts, leaving behind two major HXR sources formed around its central dip portion and a circular ribbon brightened sequentially. The expanding western fan-like field interacts intensively with the outer spine-like field, as clearly seen in running difference EUV images. We discuss these observations in favor of a scenario where the asymmetric eruption of the sigmoidal filament is initiated due to an MHD instability and further facilitated by reconnection at a quasi-null in corona; the latter is in turn enhanced by the filament eruption and subsequently produces the circular flare ribbon.

  20. Changes in the Numbers of Ribbon Synapses and Expression of RIBEYE in Salicylate-Induced Tinnitus

    Directory of Open Access Journals (Sweden)

    Feng-Ying Zhang

    2014-08-01

    Full Text Available Background: This study was performed to explore the mechanism underlying tinnitus by investigating the changes in the synaptic ribbons and RIBEYE expression in cochlear inner hair cells in salicylate-induced tinnitus. Methods: C57BL/6J mice were injected with salicylate (350 mg/kg for 10 days and grouped. Behavioral procedures were performed to assess whether the animals experienced tinnitus. The specific presynaptic RIBEYE protein and non-specific postsynaptic glutamate receptor 2&3 protein in basilar membrane samples were examined by immunofluorescent labeling. RT-PCR and Western blot assays were used to examine RIBEYE expression. Serial sections were used to build three-dimensional models using 3ds MAX software to evaluate the changes in the synaptic ribbons. Results: The administration of salicylate increased false positives in the behavioral procedure from 3 d to 10 d. The membrane profiles of inner hair cells in all mice were intact. The number of synaptic ribbons in the salicylate group increased on the 7th d and decreased on the 9th and 10th d. mRNA and protein expression of RIBEYE were initially up-regulated and later down-regulated by injecting salicylate for 10 consecutive days. Conclusion: This change in the ribbon synapses of cochlear inner hair cells in salicylate-induced mice might serve as a compensatory mechanism in the early stages of ototoxicity and contribute to tinnitus later. The alteration of RIBEYE expression could be responsible for the changes in the morphology of ribbon synapses and for salicylate-induced tinnitus.

  1. Effects of solar wind speed on the secondary energetic neutral source of the Interstellar Boundary Explorer ribbon

    Science.gov (United States)

    Zirnstein, E. J.; Funsten, H. O.; Heerikhuisen, J.; McComas, D. J.

    2016-02-01

    The Interstellar Boundary EXplorer (IBEX) ribbon is an intense energetic neutral atom (ENA) emission feature encircling the sky, spanning energies ≤0.5-6 keV. The ribbon may be produced by the "secondary ENA" mechanism, where ENAs emitted from a source plasma population inside the heliosphere propagate outside the heliopause, undergo two charge-exchange events, and become secondary ENAs that may be directed back toward Earth and detected by IBEX. In this scenario, the source plasma population is governed by the interaction of the solar wind (SW) with the interstellar medium and is thus sensitive to the global SW properties. Moreover, this scenario predicts that the distance to the source of secondary ENAs depends on the ENA energy and SW speed, which in turn may affect the shape of the ribbon. In this paper, we use a computational model of the heliosphere with simplified SW boundary conditions to analyze the influence of ENA energy and SW speed, independent of time and latitude, on the global spatial and geometric properties of the ribbon. We find a strong dependence of the simulated ribbon energy spectrum and spatial symmetry on SW speed and ENA energy, and only a slight dependence on ribbon geometry. Our results suggest a significant number of primary ENAs from the inner heliosheath may contribute to the pickup ion source population outside the heliopause, depending on the ENA energy and SW speed. The lack of variation in the simulated ribbon center as a function of ENA energy and SW speed, in contrast to the observations, implies that the asymmetry of the SW plays an important role in determining the position of the ribbon. Comparisons to the IBEX data also signify the ribbon's dependence on the properties of the local interstellar medium, particularly the interstellar magnetic field.

  2. The Effect of External Magnetic Field on Microstructure and Magnetic Properties of Melt-Spun Nd-Fe-B/Fe-Co Nanocomposite Ribbons

    Directory of Open Access Journals (Sweden)

    Xuan Truong Nguyen

    2013-01-01

    Full Text Available The ribbons Nd2Fe14B/Fe-Co were prepared with the nominal composition Nd16Fe76B8/40% wt. Fe65Co35 by the conventional and the developed magnetic field-assisted melt-spinning (MFMS techniques. Both ribbons are nanocomposites with the smooth single-phase-like magnetization loops. The 0.32 T magnetic field perpendicular to the wheel surface and assisting the melt-spinning process reduces the grain size inside the ribbon, increases the texture of the ribbon, improves the exchange coupling, and, in sequence, increases the energy product (BHmax of the isotropic powdered samples of MFMS ribbon in ~9% by comparison with that of the ribbon melt-spun conventionally. The grain size reduction effect caused by the assisted magnetic field has also been described quantitatively. The MFMS technique seems to be promising for producing high-performance nanocomposite ribbons.

  3. Illustration of the development of bacterial cellulose bundles/ribbons by Gluconacetobacter xylinus via atomic force microscopy.

    Science.gov (United States)

    Zhang, Kai

    2013-05-01

    The development of bacterial cellulose (BC) fibrils biosynthesized by Gluconacetobacter xylinus was investigated using atomic force microscopy (AFM). After various incubation times at 30 °C, both the length of BC fibrils and their average diameters increased significantly. After the first 2-h incubation, not only single BC microfibrils with an average diameter of 5.8 ± 0.7 nm were biosynthesized but single microfibrils also began to bind with each other forming bundles. After longer incubation times of 6 h, 16 h, and 48 h, only BC bundles and ribbons or even only ribbons were detectable. The development of BC fibrils and the formation of BC bundles/ribbons along with the biosynthesis time were illustrated using AFM. Furthermore, single BC fibrils were twisted in a right-handed manner. The twisting of BC fibrils possibly promoted the formation of bigger ribbons.

  4. Blue moons and Martian sunsets.

    Science.gov (United States)

    Ehlers, Kurt; Chakrabarty, Rajan; Moosmüller, Hans

    2014-03-20

    The familiar yellow or orange disks of the moon and sun, especially when they are low in the sky, and brilliant red sunsets are a result of the selective extinction (scattering plus absorption) of blue light by atmospheric gas molecules and small aerosols, a phenomenon explainable using the Rayleigh scattering approximation. On rare occasions, dust or smoke aerosols can cause the extinction of red light to exceed that for blue, resulting in the disks of the sun and moon to appear as blue. Unlike Earth, the atmosphere of Mars is dominated by micron-size dust aerosols, and the sky during sunset takes on a bluish glow. Here we investigate the role of dust aerosols in the blue Martian sunsets and the occasional blue moons and suns on Earth. We use the Mie theory and the Debye series to calculate the wavelength-dependent optical properties of dust aerosols most commonly found on Mars. Our findings show that while wavelength selective extinction can cause the sun's disk to appear blue, the color of the glow surrounding the sun as observed from Mars is due to the dominance of near-forward scattering of blue light by dust particles and cannot be explained by a simple, Rayleigh-like selective extinction explanation.

  5. Observations of an X-shaped Ribbon Flare and Its Three-dimensional Magnetic Reconnection with IRIS and SDO

    Science.gov (United States)

    Li, Ying; Qiu, Jiong; Longcope, Dana; Ding, Mingde

    2016-05-01

    We report evolution of an atypical X-shaped flare ribbon which provides novel observational evidence of three-dimensional (3D) magnetic reconnection at a separator. The flare occurred on 2014 November 9, and high-resolution slit-jaw 1330 images from IRIS reveal four chromospheric flare ribbons that converge and form an X-shape. These four ribbons are located in a quadrupolar magnetic field. Reconstruction of magnetic topology in the active region suggests the presence of a separator connecting to the X-point outlined by the ribbons. The inward motion of flare ribbons, as well as coronal loops observed by the SDO/AIA, indicates 3D magnetic reconnection between two sets of non-coplanar loops that approach laterally, and the reconnection proceeds downward to a very low height. We also study spectra of Si IV, C II, and Mg II observed with the IRIS slit, which cuts across the flare ribbons near the X-point. We have found two distinct types of line profiles. At the flare ribbon, all the lines show evident redshifts with a velocity up to 50 km/s, and the redshifts are well correlated with the line intensity and width. These redshifts suggest chromospheric condensation caused by impulsive energy deposition from the separator reconnection. While right outside the flare ribbon, the lines exhibit unshifted, symmetric, yet broadened profiles; in particular, the Si IV line is significantly broadened at the far wing. The line broadening persists for 20 minutes till after the end of the flare. The distinct spectral features near the X-point indicate different dynamics associated with the separator reconnection.

  6. Blue Man袭东京

    Institute of Scientific and Technical Information of China (English)

    Naomi Saeki; 李宝怡

    2008-01-01

    <正>20年前在美国曼克顿风靡一时的Blue Man Group,最近在东京出现,马上成为城中话题。在东京,每年有不少舞台剧演出,但是像Blue Man Group这样备受注目的,近年罕见。Blue Man Group in Tokyo于上年12月开始公演·1个月的门票早在9月中旬

  7. Modeling the Excitation of Graphene Plasmons in Periodic Grids of Graphene Ribbons: An Analytical Approach

    CERN Document Server

    Gonçalves, P A D; Bludov, Yu V; Peres, N M R

    2016-01-01

    We study electromagnetic scattering and subsequent plasmonic excitations in periodic grids of graphene ribbons. To address this problem, we develop an analytical method to describe the plasmon-assisted absorption of electromagnetic radiation by a periodic structure of graphene ribbons forming a diffraction grating for THz and mid-IR light. The major advantage of this method lies in its ability to accurately describe the excitation of graphene surface plasmons (GSPs) in one-dimensional (1D) graphene gratings without the use of both time-consuming, and computationally-demanding full-wave numerical simulations. We thus provide analytical expressions for the reflectance, transmittance and plasmon-enhanced absorbance spectra, which can be readily evaluated in any personal laptop with little-to-none programming. We also introduce a semi-analytical method to benchmark our previous results and further compare the theoretical data with spectra taken from experiments, to which we observe a very good agreement. These th...

  8. Moessbauer study of FINEMET type nanocrystalline ribbons irradiated with swift heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmann, Erno, E-mail: kuzmann@ludens.elte.hu; Stichleutner, Sandor; Sapi, Andras [Institute of Chemistry, Eoetvoes University (Hungary); Varga, Lajos Karoly [Research Institute for Solid State Physics and Optics, HAS (Hungary); Havancsak, Karoly [Eoetvoes University, Department of Materials Physics (Hungary); Skuratov, Vlamidir [Joint Institute for Nuclear Research (Russian Federation); Homonnay, Zoltan; Vertes, Attila [Institute of Chemistry, Eoetvoes University (Hungary)

    2012-03-15

    As-quenched and stress field annealed FINEMET ribbons were irradiated with 246 MeV energy Kr, 470 MeV energy Xe and 720 MeV energy Bi ions and investigated by {sup 57}Fe Moessbauer spectroscopy and XRD methods. The change in relative areas of the 2nd and 5th lines in the Moessbauer spectra indicated significant changes in the magnetic anisotropy of both as-quenched and stress annealed FINEMET due to irradiation with swift heavy ions. Differences were observed between the effect of irradiations with various ions having different energy and fluence. The effect of irradiation on the magnetic orientation in FINEMET was explained in terms of radiation induced defects. The swift heavy ion irradiation can be applied to produce FINEMET ribbons with more favorable soft magnetic properties for technological applications.

  9. Electrorheological Properties of Suspensions of Polypyrrole Ribbon Particles in Silicone Oil

    Science.gov (United States)

    Almajdalawi, Shawqi; Pavlinek, Vladimir; Cheng, Qilin; Saha, Petr; Mrlik, Miroslav; Stenicka, Martin

    2011-07-01

    A new polypyrrole (PPy) ribbon particles structure has been synthesized by solution chemistry method (oxidative polymerization) in the presence of surfactant cetyltrimethylammonium bromide (CTAB) with oxidizing agent ammonium persulfate (APS). The resulted polymer was treated with ammonium hydroxide (NH4OH) several times to obtain different sample conductivity. PPy morphology was characterized by SEM. The suspensions were prepared by dispersing PPy with different conductivities in silicone oil. The electrorheological effect (ER) for the suspensions was examined under various electric fields using a rotational rheometer. It was found that suspension of only 3 wt. % of PPy ribbon particles showed large ER effect providing yield stress of 256 Pa at 3 kV.mm-1.

  10. Crystal structures and magnetic properties of magnetite (Fe3O4)/Polyvinyl alcohol (PVA) ribbon

    Science.gov (United States)

    Ardiyanti, Harlina; Suharyadi, Edi; Kato, Takeshi; Iwata, Satoshi

    2016-04-01

    Ribbon of magnetite (Fe3O4)/Polyvinyl Alcohol (PVA) nanoparticles have been successfully fabricated with various concentration of PVA synthesized by co-precipitation method. Particle size of nanoparticles Fe3O4 sample and ribbon Fe3O4/PVA 25% sample is about 9.34 nm and 11.29 nm, respectively. The result of Vibrating Sample Magnetometer (VSM) showed that saturation magnetization value decreased from 76.99 emu/g to 15.01 emu/g and coercivity increased from 49.30 Oe to 158.35 Oe as increasing concentration of PVA. Atomic Force Microscopy (AFM) analysis showed that encapsulated PVA given decreasing agglomeration, controlled shape of nanoparticles Fe3O4 more spherical and dispersed. Surface roughness decreased with increasing concentration of PVA.

  11. Enhancement of the martensitic transformation and magnetocaloric effect of Ni-Mn-V-Sn ribbons by annealing treatment

    Energy Technology Data Exchange (ETDEWEB)

    Xuan, H.C. [College of Materials Science and Engineering, Taiyuan University of Technology (China); National Laboratory of Solid State Microstructures and Key Laboratory of Nanomaterials for Jiang Su Province, Nanjing University (China); Zhang, Y.Q.; Li, H.; Han, P.D. [College of Materials Science and Engineering, Taiyuan University of Technology (China); Wang, D.H.; Du, Y.W. [National Laboratory of Solid State Microstructures and Key Laboratory of Nanomaterials for Jiang Su Province, Nanjing University (China)

    2015-09-15

    The rapidly solidified Ni{sub 41.98}Mn{sub 42.97}V{sub 2.08}Sn{sub 12.97} ribbons are prepared by the melt-spinning technique. The microstructure, martensitic transformation (MT), and magnetocaloric effect of the ribbons are greatly affected by annealing treatment. The equiaxed crystallized grains with the relatively homogeneous size distribution are observed for these ribbons. After annealing, the grain size becomes obviously large, the lattice constants decreases, and the exchange bias effect gets improved. The MT temperatures increase obviously for the annealed ribbons. Large magnetic entropy change (ΔS) is obtained in the annealed Ni-Mn-V-Sn ribbons. The peak values of ΔS in the annealed ribbons are 41.6 and -2.3 J kg{sup -1} K{sup -1} in the vicinity of MT temperature and Curie temperature of austenite, respectively, for the field change of 30 kOe. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Fabrication of Fe-6.5wt%Si Ribbons by Melt Spinning Method on Large Scale

    Directory of Open Access Journals (Sweden)

    Y. F. Liang

    2015-01-01

    Full Text Available Melt spinning method has been widely applied for fabrication of Fe-based amorphous/nanocrystalline ribbons in industry. Compared with Fe-based amorphous/nanocrystalline alloys, Fe-6.5wt%Si high silicon steel is of low cost and has comparable excellent soft magnetic properties. Due to higher melting point and absence of supercooled liquid region, fabrication of Fe-6.5wt%Si ribbons is very hard and is only on lab scale. In this paper, we report that large scale fabrication of Fe-6.5wt%Si ribbons was successful and microstructures, ordered structures, and mechanical and soft magnetic properties of the ribbons were investigated. Due to rapid solidification rate, the ribbons were of ultrafine grains, and low degree of order and exhibited some extent of bending and tensile ductility. After heat treatment, excellent soft magnetic properties were obtained. Due to near-zero magnetostriction, the ribbons are promising to be used in electric devices with high frequencies where low noises are required.

  13. First order structural transformation and inverse magnetocaloric effect in melt-spun Ni-Mn-Sn ribbons

    Science.gov (United States)

    Babita, I.; Patil, S. I.; Ram, S.

    2010-05-01

    First order structural transformation (FOST) and inverse magnetocaloric effect (IMCE) were investigated in melt-spun ribbons of Ni49Mn37.4Sn13.6 and Ni50Mn34.5Sn15.5 Heusler alloys. Thermal and magnetic characterization of the ribbons revealed the existence of FOST. Interestingly, in the Ni49Mn37.4Sn13.6 ribbon, the structural transformation occurs prior to magnetic transition incongruous to that observed in the Ni50Mn34.5Sn15.5 ribbons. In addition to FOST, the ribbons also exhibit a large IMCE at low magnetic field. A maximum positive magnetic entropy change ΔSM ~ 6.0 J kg-1 K-1 and ~1.6 J kg-1 K-1 for a field change of 2 T was observed in the Ni49Mn37.4Sn13.6 and Ni50Mn34.5Sn15.5 ribbons, respectively.

  14. Gradient Distribution of Martensite Phase in Melt-Spun Ribbons of a Fe-Ni-Ti-Al Alloy.

    Science.gov (United States)

    Bondar, Volodymyr; Danilchenko, Vitalij; Dzevin, Ievgenij

    2016-12-01

    Metallographic, X-ray diffraction and magnetometric analysis were used to study the regularities of martensitic transformation in melt-spun ribbons of a Fe - 28 wt. % Ni - 2.1 wt. % Ti - 2 wt. % Al - 0.05 wt. % C alloy. The substantial differences in volume fractions of the martensite phase in local regions of thin melt-spun ribbons of the alloy are related to the size effect of the transformation and structural inhomogeneity of the ribbons. The distribution of austenitic grain size in different local areas of melt-spun ribbons is significantly different. The principal factor for changing the completeness of the martensitic transformation is the size effect of transformation. Difference in the martensite volume fraction in local regions of a ribbon is mainly determined by the different volume fractions of ultrafine-grained (500-1000 nm) and nanosized (80-100 nm and less) initial austenite grains, in which the transformation was slowed down or completely suppressed. Other factors almost do not affect the completeness of the martensitic transformation. The strong stabilizing effect of the reverse α-γ transformation with respect to the subsequent direct γ-α transformation in the melt-spun ribbons is also related to the grain size effect.

  15. Electrorheological Properties of Suspensions of Polypyrrole Ribbon Particles in Silicone Oil

    OpenAIRE

    Almajdalawi, Shawqi; Pavlínek, Vladimír; Cheng, Qilin; Sáha, Petr; Mrlík, Miroslav; Stěnička, Martin

    2011-01-01

    A new polypyrrole (PPy) ribbon particles structure has been synthesized by solution chemistry method (oxidative polymerization) in the presence of surfactant cetyltrimethylammonium bromide (CTAB) with oxidizing agent ammonium persulfate (APS). The resulted polymer was treated with ammonium hydroxide (NH4OH) several times to obtain different sample conductivity. PPy morphology was characterized by SEM. The suspensions were prepared by dispersing PPy with different conductivities in silicone oi...

  16. The Electromechanical Responses of Suspended Graphene Ribbons for Electrostatic Discharge Applications

    Science.gov (United States)

    Zhang, Wei

    This dissertation presents a novel suspended graphene ribbon device for electrostatic discharge (ESD) applications. The device structure is proposed and fabricated after careful design considerations. Compared to the conventional ESD devices such as diodes, bipolar junction transistors (BJTs), and metal-oxide-semiconductor field-effect transistors (MOSFETs), the proposed device structure is believed to render several advantages including zero leakage, low parasitic effects, fast response, and high current carrying capability, etc. A process flow is developed for higher yield and reliability of the suspended graphene ribbon device which is very delicate in nature. Direct current (DC) and transmission-line pulse test (TLP) measurements are carried out to investigate the switch-on behavior of the device which is crucial for ESD protection. DC measurement with a different configuration is used to characterize the mechanical shape evolution of the graphene ribbon upon biasing. Finite Element Simulations are also conducted to verify the experimental results, which are in good agreements. Furthermore, the breakdown properties of graphene ribbons are tested using TLP. It is found that graphene has a better current drivability compared to copper wires which is widely used as interconnects in integrated circuits (ICs). Also, bi-layer graphene has a higher breakdown current than monolayer graphene which indicates that multilayer graphene should be superior in current discharging. Last, Ab inito calculations are carried out to study the growth mechanism of multilayer graphene which is needed for graphene homo-epitaxy with precise control. It is found that a carbon cluster with six carbon atoms has the smallest kinetic barrier thus largest surface diffusivity during surface diffusion. So it is believed to be the most favorable diffusing species for graphene homo-epitaxy.

  17. Magnetocaloric properties of rapidly solidified Dy{sub 3}Co alloy ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez Llamazares, J. L., E-mail: jose.sanchez@ipicyt.edu.mx; Flores-Zúñiga, H.; Sánchez-Valdés, C. F. [Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José 2055 Col. Lomas 4" a, San Luis Potosí, S.L.P. 78216 (Mexico); Álvarez-Alonso, Pablo [Departamento de Electricidad y Electrónica, UPV/EHU, 48940 Leioa (Spain); Lara Rodríguez, G. A. [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, México, D. F. 04510 (Mexico); Fernández-Gubieda, M. L. [Departamento de Electricidad y Electrónica, UPV/EHU, 48940 Leioa (Spain); BC Materials, Camino de Ibaizabal, Edificio 500, Planta 1, Parque Científico y Tecnológico de Zamudio, 48160 Derio (Spain)

    2015-05-07

    The magnetic and magnetocaloric (MC) properties of melt-spun ribbons of the Dy{sub 3}Co intermetallic compound were investigated. Samples were fabricated in an Ar environment using a homemade melt spinner system at a linear speed of the rotating copper wheel of 40 ms{sup −1}. X-ray diffraction analysis shows that ribbons crystallize into a single-phase with the Fe{sub 3}C-type orthorhombic crystal structure. The M(T) curve measured at 5 mT reveals the occurrence of a transition at 32 K from a first to a second antiferromagnetic (AFM) state and an AFM-to-paramagnetic transition at T{sub N} = 43 K. Furthermore, a metamagnetic transition is observed below T{sub N}, but the magnetization change ΔM is well below the one reported for bulk alloys. Below 12 K, large inverse MC effect and hysteresis losses are observed. This behavior is related to the metamagnetic transition. For a magnetic field change of 5 T (2 T) applied along the ribbon length, the produced ribbons show a peak value of the magnetic entropy change ΔS{sub M}{sup peak} of −6.5 (− 2.1) Jkg{sup −1}K{sup −1} occurring close to T{sub N} with a full-width at half-maximum δT{sub FWHM} of 53 (37) K, and refrigerant capacity RC = 364 (83) Jkg{sup −1} (estimated from the product |ΔS{sub M}{sup peak}| × δT{sub FWHM})

  18. Highly Toxic Ribbon Worm Cephalothrix simula Containing Tetrodotoxin in Hiroshima Bay, Hiroshima Prefecture, Japan

    Directory of Open Access Journals (Sweden)

    Manabu Asakawa

    2013-02-01

    Full Text Available In 1998, during a toxicological surveillance of various marine fouling organisms in Hiroshima Bay, Japan, specimens of the ribbon worm, Cephalothrix simula (Nemertea: Palaeonemertea were found. These ribbon worms contained toxins with extremely strong paralytic activity. The maximum toxicity in terms of tetrodotoxin (TTX was 25,590 mouse units (MU per gram for the whole worm throughout the monitoring period. The main toxic component was isolated and recrystallized from an acidified methanolic solution. The crystalline with a specific toxicity of 3520 MU/mg was obtained and identified as TTX by high performance liquid chromatography (HPLC-fluorescent detection (FLD (HPLC-FLD, electrospray ionization-mass spectrometry (ESI-MS, infrared (IR, nuclear magnetic resonance (NMR and gas chromatography–mass spectrometry (GC-MS. The highest toxicity of C. simula exceeded the human lethal dose per a single worm. A toxicological surveillance of C. simula from 1998 to 2005 indicated approximately 80% of the individuals were ranked as “strongly toxic” (≥1000 MU/g. Forty-eight percent of the specimens possessed toxicity scores of more than 2000 MU/g. Seasonal variations were observed in the lethal potency of C. simula. Specimens collected on January 13, 2000 to December 26, 2000 showed mean toxicities of 665–5300 MU/g (n = 10. These data prompted a toxicological surveillance of ribbon worms from other localities with different habitats in Japan, including Akkeshi Bay (Hokkaido under stones on rocky intertidal beaches, as well as Otsuchi (Iwate among calcareous tubes of serpulid polychaetes on rocky shores. Within twelve species of ribbon worms examined, only C. simula possessed extremely high toxicity. Therefore, C. simula appears to show generally high toxicity irrespective of their locality and habitat.

  19. Development Of An 80'-Diameter Ribbon Drogue Parachute For The NASA X-38 Vehicle

    Science.gov (United States)

    Behr, Vance L.; Wolf, Dean F.; Rutledge, Bruce A.; Hillebrandt, F. David

    2001-01-01

    The NASA X-38 program required a larger, more robust drogue parachute. A multi-organizational team from NASA, Sandia National Laboratories, United Space Alliance, and Pioneer Aerospace Corporation has developed and tested a new 80-ft.-dia., quarter-spherical, ribbon drogue parachute. The design requirements, design specifics, margin analyses, and results of testing are all discussed herein. Some of the weight advantages of switching from Kevlar to Zylon for radial, line and riser materials are presented.

  20. Vortex core timelines and ribbon summarizations: flow summarization over time and simulation ensembles

    Science.gov (United States)

    Chan, Alexis Y. L.; Lee, Joohwi; Taylor, Russell M.

    2013-01-01

    We present two new vortex-summarization techniques designed to portray vortex motion over an entire simulation and over an ensemble of simulations in a single image. Linear "vortex core timelines" with cone glyphs summarize flow over all time steps of a single simulation, with color varying to indicate time. Simplified "ribbon summarizations" with hue nominally encoding ensemble membership and saturation encoding time enable direct visual comparison of the distribution of vortices in time and space for a set of simulations.

  1. Brain responses to violet, blue, and green monochromatic light exposures in humans: prominent role of blue light and the brainstem.

    Directory of Open Access Journals (Sweden)

    Gilles Vandewalle

    Full Text Available BACKGROUND: Relatively long duration retinal light exposure elicits nonvisual responses in humans, including modulation of alertness and cognition. These responses are thought to be mediated in part by melanopsin-expressing retinal ganglion cells which are more sensitive to blue light than violet or green light. The contribution of the melanopsin system and the brain mechanisms involved in the establishment of such responses to light remain to be established. METHODOLOGY/PRINCIPAL FINDINGS: We exposed 15 participants to short duration (50 s monochromatic violet (430 nm, blue (473 nm, and green (527 nm light exposures of equal photon flux (10(13ph/cm(2/s while they were performing a working memory task in fMRI. At light onset, blue light, as compared to green light, increased activity in the left hippocampus, left thalamus, and right amygdala. During the task, blue light, as compared to violet light, increased activity in the left middle frontal gyrus, left thalamus and a bilateral area of the brainstem consistent with activation of the locus coeruleus. CONCLUSION/SIGNIFICANCE: These results support a prominent contribution of melanopsin-expressing retinal ganglion cells to brain responses to light within the very first seconds of an exposure. The results also demonstrate the implication of the brainstem in mediating these responses in humans and speak for a broad involvement of light in the regulation of brain function.

  2. Laser directed lithography of asymmetric graphene ribbons on a polydimethylsiloxane trench structure.

    Science.gov (United States)

    Tian, He; Yang, Yi; Xie, Dan; Ren, Tian-Ling; Shu, Yi; Sun, Hui; Zhou, Chang-Jian; Liu, Xuan; Tao, Lu-Qi; Ge, Jie; Zhang, Cang-Hai; Zhang, Yuegang

    2013-05-14

    Recently, manipulating heat transport by asymmetric graphene ribbons has received significant attention, in which phonons in the carbon lattice are used to carry energy. In addition to heat control, asymmetric graphene ribbons might also have broad applications in renewable energy engineering, such as thermoelectric energy harvesting. Here, we transfer a single sheet of graphene over a 5 μm trench of polydimethylsiloxane (PDMS) structure. By using a laser (1.77 mW, 1 μm diameter spot size, 517 nm wavelength) focusing on one side of the suspended graphene, a triangular shaped graphene ribbon is obtained. As the graphene has a negative thermal expansion coefficient, local laser heating could make the affected graphene area shrink and eventually break. Theoretical calculation shows that the 1.77 mW laser could create a local hot spot as high as 1462.5 °C, which could induce an asymmetric shape structure. We also find the temperature coefficient (-13.06 cm(-1) mW) of suspended graphene on PDMS trench substrate is ten times higher than that reported on SiO2/Si trench substrate. Collectively, our results raise the exciting prospect that the realization of graphene with asymmetric shape on thermally insulating substrate is technologically feasible, which may open up important applications in thermal circuits and thermal management.

  3. Aeroelastic modelling of a Piezo-solar tensioned energy harvesting ribbon

    Science.gov (United States)

    Chatterjee, Punnag; Bryant, Matthew

    2016-04-01

    A multifunctional compliant structure is proposed that can harvest electrical power from both incident sunlight and ambient mechanical energy including wind flow or vibration. The proposed energy harvesting device consists of a slender, ribbon-like, flexible thin film solar cell that is laminated with piezoelectric patches at either ends and mounted in the cross flow of wind in a clamped-clamped end condition with an adjustable axial preload. Taking this motivation forward a system model of the energy harvester is developed which captures the structural response of the solar ribbon and couples it with Theodorsen unsteady aerodynamics to predict the flutter boundary conditions as a function of applied axial preload tension. The model also accounts for geometric and material discontinuities, by effective use of Transfer Matrix Method (TMM) modeling technique both in bending and torsional degrees of freedom. This paper also derives TMM technique for torsional vibrations with an applied axial load from first principles, verifies the method and presents its applicability for the proposed energy harvester. The paper also points out that the flutter instability arises out of different structural modes at different values applied axial tension, with the help of a sample modal convergence plot. The analysis also presents the possibility to tune the solar ribbon to operate at an optimal reduced frequency by adjusting the applied axial preload.

  4. The correlation between expansion speed and magnetic field in solar flare ribbons

    Institute of Scientific and Technical Information of China (English)

    XIE WenBin; WANG HaiMin; JING Ju; BAO XingMing; ZHANG HongQi

    2009-01-01

    In this paper, we study the correlation between the expansion speed of two-ribbon flares and the mag-netic field measured in the ribbon location, and compare such correlation for two events with different magnetic configurations. These two events are: an M1.0 flare in the quiet sun on September 12, 2000 and an X2.3 flare in Active Region NOAA 9415 on April 10, 2001. The magnetic configuration of the M1.0 flare is simple, while that of X2.3 event is complex. We have derived a power-law correlation between the ribbon expansion speed (V_r) and the longitudinal magnetic field (B_z) with an empirical relationship V_r=A×B_(z~(-δ)), where A is a constant and δ is the index of the power-law correlation. We have found that δ for the M1.0 flare in the simple magnetic configuration is larger than that for the X2.3 flare in the complex magnetic configuration.

  5. Mixing behaviour of cohesive and non-cohesive particle mixtures in a ribbon mixer

    Science.gov (United States)

    Musha, H.; Dong, K.; Chandratilleke, G. R.; Bridgwater, J.; Yu, A. B.

    2013-06-01

    Ribbon mixers are used in a wide range of applications involving pharmaceuticals, ceramics and cosmetics, to name a few. Here, the discrete element method is used to investigate the effect of impeller speed on the mixing behaviours of cohesive as well as non-cohesive particle mixtures in a ribbon mixer, which has a horizontal cylindrical vessel. The mixing behaviours are characterized by particle-scale and macroscopic mixing indexes. Simulations show that the mixing rate increases with the impeller speed for both the cohesive and non-cohesive mixtures up to a certain speed, beyond which it showed a reduction. There is a possibility that the mixture quality becomes poorer at higher impeller speeds for the non-cohesive particles, but it was not the case with the cohesive particles. Inspection of velocity fields shows that many local recirculation regions exist in the case of non-cohesive particle mixing, preventing the overall mixing. By contrast, in the case of the cohesive mixture, there exists a circumferential motion about the shaft and a convective motion in the horizontal axial direction, improving the particle mixing. Force analyses are also carried out, which show that the particle contact forces increase with the impeller speed for non-cohesive particles, but in the case of cohesive particles, they increase initially with the impeller speed, and then show a reduction after a certain speed. The results will be useful in selecting operation conditions of a ribbon mixer.

  6. Comparisons of the Interstellar Magnetic Field Directions obtained from the IBEX Ribbon and Interstellar Polarizations

    CERN Document Server

    Frisch, Priscilla C; Berdyugin, Andrei; Funsten, Herbert O; Magalhaes, Mario; McComas, David J; Piirola, Vilppu; Schwadron, Nathan A; Slavin, Jonathan D; Wiktorowicz, Sloane J

    2010-01-01

    Variations in the spatial configuration of the interstellar magnetic field (ISMF) near the Sun can be constrained by comparing the ISMF direction at the heliosphere found from the Interstellar Boundary Explorer spacecraft (IBEX) observations of a 'Ribbon' of energetic neutral atoms (ENAs), with the ISMF direction derived from optical polarization data for stars within ~40 pc. Using interstellar polarization observations towards ~30 nearby stars within 90 deg of the heliosphere nose, we find that the best fits to the polarization position angles are obtained for a magnetic pole directed towards ecliptic coordinates of lambda, beta 263 deg, 37 deg (or galactic coordinates of L,B 38 deg, 23deg), with uncertainties of +/- 35 deg, based on the broad minimum of the best fits and the range of data quality. This magnetic pole is 33 deg from the magnetic pole that is defined by the center of the arc of the ENA Ribbon. The IBEX ENA ribbon is seen in sightlines that are perpendicular to the ISMF as it drapes over the he...

  7. Plasma immersion ion implantation of boron for ribbon silicon solar cells

    Directory of Open Access Journals (Sweden)

    Derbouz K.

    2013-09-01

    Full Text Available In this work, we report for the first time on the solar cell fabrication on n-type silicon RST (for Ribbon on Sacrificial Template using plasma immersion ion implantation. The experiments were also carried out on FZ silicon as a reference. Boron was implanted at energies from 10 to 15 kV and doses from 1015 to 1016 cm-2, then activated by a thermal annealing in a conventional furnace at 900 and 950 °C for 30 min. The n+ region acting as a back surface field was achieved by phosphorus spin-coating. The frontside boron emitter was passivated either by applying a 10 nm deposited SiOX plasma-enhanced chemical vapor deposition (PECVD or with a 10 nm grown thermal oxide. The anti-reflection coating layer formed a 60 nm thick SiNX layer. We show that energies less than 15 kV and doses around 5 × 1015 cm-2 are appropriate to achieve open circuit voltage higher than 590 mV and efficiency around 16.7% on FZ-Si. The photovoltaic performances on ribbon silicon are so far limited by the bulk quality of the material and by the quality of the junction through the presence of silicon carbide precipitates at the surface. Nevertheless, we demonstrate that plasma immersion ion implantation is very promising for solar cell fabrication on ultrathin silicon wafers such as ribbons.

  8. Plasma immersion ion implantation of boron for ribbon silicon solar cells

    Science.gov (United States)

    Derbouz, K.; Michel, T.; De Moro, F.; Spiegel, Y.; Torregrosa, F.; Belouet, C.; Slaoui, A.

    2013-09-01

    In this work, we report for the first time on the solar cell fabrication on n-type silicon RST (for Ribbon on Sacrificial Template) using plasma immersion ion implantation. The experiments were also carried out on FZ silicon as a reference. Boron was implanted at energies from 10 to 15 kV and doses from 1015 to 1016 cm-2, then activated by a thermal annealing in a conventional furnace at 900 and 950 °C for 30 min. The n+ region acting as a back surface field was achieved by phosphorus spin-coating. The frontside boron emitter was passivated either by applying a 10 nm deposited SiOX plasma-enhanced chemical vapor deposition (PECVD) or with a 10 nm grown thermal oxide. The anti-reflection coating layer formed a 60 nm thick SiNX layer. We show that energies less than 15 kV and doses around 5 × 1015 cm-2 are appropriate to achieve open circuit voltage higher than 590 mV and efficiency around 16.7% on FZ-Si. The photovoltaic performances on ribbon silicon are so far limited by the bulk quality of the material and by the quality of the junction through the presence of silicon carbide precipitates at the surface. Nevertheless, we demonstrate that plasma immersion ion implantation is very promising for solar cell fabrication on ultrathin silicon wafers such as ribbons.

  9. The correlation between expansion speed and magnetic field in solar flare ribbons

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper, we study the correlation between the expansion speed of two-ribbon flares and the magnetic field measured in the ribbon location, and compare such correlation for two events with different magnetic configurations. These two events are: an M1.0 flare in the quiet sun on September 12, 2000 and an X2.3 flare in Active Region NOAA 9415 on April 10, 2001. The magnetic configuration of the M1.0 flare is simple, while that of X2.3 event is complex. We have derived a power-law correlation between the ribbon expansion speed (V r) and the longitudinal magnetic field (Bz) with an empirical relationship V r = A×Bz-δ, where A is a constant and δ is the index of the power-law correlation. We have found that δ for the M1.0 flare in the simple magnetic configuration is larger than that for the X2.3 flare in the complex magnetic configuration.

  10. Magnetocaloric Properties Response in High-Speed Melt-Spun La-Ce-Fe-Si Ribbons

    Science.gov (United States)

    Hou, Xueling; Han, Ning; Xue, Yun; Lu, Qianqian; Wang, Xiaochen; Phan, Manh-Huong

    2016-10-01

    The structure and magnetocaloric properties of La-Ce-Fe-Si alloys have been studied. The samples were prepared by melt spinning, the surface speed of the Cu wheel being 55 m/s. The as-spun ribbons were subsequently annealed at 1273 K for different times (10 min-1 h) and then quenched to room temperature. When the annealing time was 20 min, on a 1.5-T applied magnetic field, the maximum magnetic entropy change (Δ S M) of the ribbons reached values of 33.8 J/kg K at the Curie temperature of T C ˜ 182 K. When the annealing time was longer than 20 min, the maximum magnetic entropy change (|Δ S M,Max|) tended to decrease while the T C remained almost unchanged. In the annealing process, La/Ce located at grain boundaries was easily oxidized on the ribbon surface. The presence of large grain sizes and La2O3 or LaO were shown to degrade the magnetocaloric properties. On the other hand, the substitution of Ce for La improved the magnetocaloric effect of La-Fe-Si compounds, which is of practical importance for magnetic refrigeration.

  11. A Circular-ribbon Solar Flare Following an Asymmetric Filament Eruption

    CERN Document Server

    Liu, Chang; Liu, Rui; Lee, Jeongwoo; Pariat, Etienne; Wiegelmann, Thomas; Liu, Yang; Kleint, Lucia; Wang, Haimin

    2015-01-01

    The dynamic properties of flare ribbons and the often associated filament eruptions can provide crucial information on the flaring coronal magnetic field. This Letter analyzes the GOES-class X1.0 flare on 2014 March 29 (SOL2014-03-29T17:48), in which we found an asymmetric eruption of a sigmoidal filament and an ensuing circular flare ribbon. Initially both EUV images and a preflare nonlinear force-free field model show that the filament is embedded in magnetic fields with a fan-spine-like structure. In the first phase, which is defined by a weak but still increasing X-ray emission, the western portion of the sigmoidal filament arches upward and then remains quasi-static for about five minutes. The western fan-like and the outer spine-like fields display an ascending motion, and several associated ribbons begin to brighten. Also found is a bright EUV flow that streams down along the eastern fan-like field. In the second phase that includes the main peak of hard X-ray (HXR) emission, the filament erupts, leavi...

  12. Curling dynamics of naturally curved ribbons from high to low Reynolds numbers

    Science.gov (United States)

    Albarran Arriagada, Octavio; Massiera, Gladys; Abkarian, Manouk

    2012-11-01

    Curling deformation of thin elastic sheets appears in numerous structures in nature, such as membranes of red blood cells, epithelial tissues or green algae colonies to cite just a few examples. However, despite its ubiquity, the dynamics of curling propagation in a naturally curved material remains still poorly investigated. Here, we present a coupled experimental and theoretical study of the dynamical curling deformation of naturally curved ribbons. Using thermoplastic and metallic ribbons molded on cylinders of different radii, we tune separately the natural curvature and the geometry to study curling dynamics in air, water and in viscous oils, thus spanning a wide range of Reynolds numbers. Our theoretical and experimental approaches separate the role of elasticity, gravity and hydrodynamic dissipation from inertia and emphasize the fundamental differences between the curling of a naturally curved ribbon and a rod described by the classical Elastica. Our work shows evidence for the propagation of a single instability front, selected by a local buckling condition. We show that depending on gravity, and both the Reynolds and the Cauchy numbers, the curling speed and shape are modified by the large scale drag and the local lubrication forces. This work was supported by the French Ministry of Research, the CNRS Physics-Chemistry-Biology Interdisciplinary Pro- gram, the University Montpellier 2 Interdisciplinary Program and the Region Languedoc-Roussillon.

  13. Atlas-based rib-bone detection in chest X-rays.

    Science.gov (United States)

    Candemir, Sema; Jaeger, Stefan; Antani, Sameer; Bagci, Ulas; Folio, Les R; Xu, Ziyue; Thoma, George

    2016-07-01

    This paper investigates using rib-bone atlases for automatic detection of rib-bones in chest X-rays (CXRs). We built a system that takes patient X-ray and model atlases as input and automatically computes the posterior rib borders with high accuracy and efficiency. In addition to conventional atlas, we propose two alternative atlases: (i) automatically computed rib bone models using Computed Tomography (CT) scans, and (ii) dual energy CXRs. We test the proposed approach with each model on 25 CXRs from the Japanese Society of Radiological Technology (JSRT) dataset and another 25 CXRs from the National Library of Medicine CXR dataset. We achieve an area under the ROC curve (AUC) of about 95% for Montgomery and 91% for JSRT datasets. Using the optimal operating point of the ROC curve, we achieve a segmentation accuracy of 88.91±1.8% for Montgomery and 85.48±3.3% for JSRT datasets. Our method produces comparable results with the state-of-the-art algorithms. The performance of our method is also excellent on challenging X-rays as it successfully addressed the rib-shape variance between patients and number of visible rib-bones due to patient respiration.

  14. China Mobile: Expanding "Blue Ocean"

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Driving force is crucial for realizing high-speed growth. The strong driving force from "Blue Ocean Strategy" is an important advantage for China Mobile to realize harmonious and leap-forward development.

  15. Karner Blue Butterfly Recovery Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This recovery plan has been prepared by the Karner Blue Butterfly Recovery Team under the leadership of Dr. David Andow, University of Minnesota-St. Paul. Dr. John...

  16. Ecology of blue straggler stars

    CERN Document Server

    Carraro, Giovanni; Beccari, Giacomo

    2015-01-01

    The existence of blue straggler stars, which appear younger, hotter, and more massive than their siblings, is at odds with a simple picture of stellar evolution. Such stars should have exhausted their nuclear fuel and evolved long ago to become cooling white dwarfs. They are found to exist in globular clusters, open clusters, dwarf spheroidal galaxies of the Local Group, OB associations and as field stars. This book summarises the many advances in observational and theoretical work dedicated to blue straggler stars. Carefully edited extended contributions by well-known experts in the field cover all the relevant aspects of blue straggler stars research: Observations of blue straggler stars in their various environments; Binary stars and formation channels; Dynamics of globular clusters; Interpretation of observational data and comparison with models. The book also offers an introductory chapter on stellar evolution written by the editors of the book.

  17. Martensitic Transformation and Magnetic-Field-Induced Strain in Magnetic Shape Memory Alloy NiMnGa Melt-Spun Ribbon

    Institute of Scientific and Technical Information of China (English)

    Shihai GUO; Yanghuan ZHANG; Jianliang LI; Baiyun QUAN; Yan QI; Xinlin WANG

    2005-01-01

    A magnetic shape memory alloy with nonstoichiometric Ni5oMn27Ga23 was prepared by using melt-spinning technology. The martensitic transformation and the magnetic-field-induced strain (MFIS) of the polycrystalline melt-spun ribbon were investigated. The experimental results showed that the melt-spun ribbons underwent thermal-elastic martensitic transformation and reverse transformation in cooling and heating process and exhibited typical thermoelastic shape memory effect. However the start temperature for martensitic transformation decreased from 286 K for as-cast alloy to 254 K for as-quenched ribbon and Curie temperature remains approximately constant. A particular internal stress induced by melt-spinning resulted in the formation of a texture structure in the ribbons, which made the ribbons obtain larger martensitic transformation strain and MFIS. The internal stress was released substantially after annealing, which resulted in a decrease of MFIS of the ribbons.

  18. A change of task prolongs early processes: evidence from ERPs in lexical tasks.

    Science.gov (United States)

    Elchlepp, Heike; Lavric, Aureliu; Monsell, Stephen

    2015-04-01

    Switching tasks costs time. Allowing time to prepare reduces the cost, but usually leaves an irreducible "residual cost." Most accounts of this residual cost locate it within the response-selection stage of processing. To determine which processing stage is affected, we measured event-related potentials (ERPs) as participants performed a reading task or a perceptual judgment task, and examined the effect of a task switch on early markers of lexical processing. A task cue preceding a string of blue and red letters instructed the participant either to read the letter string (for a semantic classification in Experiment 1, and a lexical decision in Experiment 2) or to judge the symmetry of its color pattern. In Experiment 1, having to switch to the reading task delayed the evolution of the effect of word frequency on the reading task ERP by a substantial fraction of the effect on reaction time (RT). In Experiment 2, a task switch delayed the onset of the effect of lexical status on the ERP by about the same extent that it prolonged the RT. These effects indicate an early locus of (most of) the residual switch cost: We propose that this reflects a form of task-related attentional inertia. Other findings have implications for the automaticity of lexical access: Effects of frequency, lexicality, and orthographic familiarity on ERPs in the symmetry task indicated involuntary, but attenuated, orthographic and lexical processing even when attention was focused on a nonlexical property.

  19. Magnetoimpedance studies on laser and microwave annealed Fe{sub 66}Ni{sub 7}si{sub 7}B{sub 20} ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Kotagiri, Ganesh [Advanced Magnetic Materials Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Ramarao, S.D. [Microwave Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Markandeyulu, G., E-mail: mark@iitm.ac.in [Advanced Magnetic Materials Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India)

    2015-05-15

    Magnetoimpedance (MI) has been investigated in the laser and microwave annealed Fe{sub 66}Ni{sub 7}Si{sub 7}B{sub 20} ribbons. The largest MI [(MI){sub m}] values of the ribbons annealed using laser with energies of 150, 200 and 250 mJ/pulse (mJp) are 25% (at 7 MHz), 30% (at 5 MHz) and 21% (at 7 MHz) respectively. The effect of domain wall pinning on MI was observed as field insensitive regions in the MI profiles in the ribbon annealed using 150 mJp energy. Flower shaped grains in amorphous matrix in the ribbon annealed with 200 mJp energy are responsible for highest (MI){sub m} due to the least anisotropy. In the ribbons annealed for 40, 45 and 50 min at 400 °C using microwaves, (MI){sub m} values are 35% (at 5 MHz), 46% (at 6 MHz) and 29% (at 7 MHz) respectively. The large DC conductivity and the least anisotropy (smallest H{sub k} values) in the ribbon microwave annealed for 45 min at 400 °C resulted in (MI){sub m} reaching its highest value in the ribbons investigated. - Highlights: • Magnetoimpedance studied on Fe{sub 66}Ni{sub 7}Si{sub 7}B{sub 20} ribbons annealed using laser/microwaves. • Domain wall pinning observed in the ribbon annealed with 150 mJ/pulse of laser. • Flower shaped grains observed in the ribbon annealed with 200 mJ/pulse of laser. • Large magnetoimpedance and least anisotropy observed in the above ribbon. • Microwave annealed ribbons exhibited conductivity-magnetoimpedance correlation.

  20. "Clothed in triple blues": sorting out the Italian blues.

    Science.gov (United States)

    Bimler, David; Uusküla, Mari

    2014-04-01

    Cross-cultural comparisons of color perception and cognition often feature versions of the "similarity sorting" procedure. By interpreting the assignment of two color samples to different groups as an indication that the dissimilarity between them exceeds some threshold, sorting data can be regarded as low-resolution similarity judgments. Here we analyze sorting data from speakers of Italian, Russian, and English, applying multidimensional scaling to delineate the boundaries between perceptual categories while highlighting differences between the three populations. Stimuli were 55 color swatches, predominantly from the blue region. Results suggest that at least two Italian words for "blue" are basic, a similar situation to Russian, in contrast to English where a single "blue" term is basic.

  1. Why Do Proteins Glow Blue?

    CERN Document Server

    Sarkar, Sohini; Hazra, Partha; Mandal, Pankaj

    2014-01-01

    Recent literatures reported blue-green emission from amyloid fibril as exclusive signature of fibril formation. This unusual visible luminescence is regularly used to monitor fibril growth. Blue-green emission has also been observed in crystalline protein and in solution. However, the origin of this emission is not known exactly. Our spectroscopic study of serum proteins reveals that the blue-green emission is a property of protein monomer. Evidences suggest that semiconductor-like band structure of proteins with the optical band-gap in the visible region is possibly the origin of this phenomenon. We show here that the band structure of proteins is primarily the result of electron delocalization through the peptide chain, rather than through the hydrogen bond network in secondary structure.

  2. The Role of Erupting Sigmoid in Triggering a Flare with Parallel and Large-Scale Quasi-Circular Ribbons

    CERN Document Server

    Joshi, Navin Chandra; Sun, Xudong; Wang, Haimin; Magara, Tetsuya; Moon, Y -J

    2015-01-01

    In this paper, we present observations and analysis of an interesting sigmoid formation, eruption and the associated flare that occurred on 2014 April 18 using multi-wavelength data sets. We discuss the possible role of the sigmoid eruption in triggering the flare, which consists of two different set of ribbons: parallel ribbons as well as a large-scale quasi-circular ribbon. Several observational evidence and nonlinear force-free field extrapolation results show the existence of a large-scale fan-spine type magnetic configuration with a sigmoid lying under a section of the fan dome. The event can be explained with the following two phases. During the pre-flare phase, we observed the formation and appearance of sigmoid via tether-cutting reconnection between the two sets of sheared fields under the fan dome. The second, main flare phase, features the eruption of the sigmoid, the subsequent flare with parallel ribbons, and a quasi-circular ribbon. We propose the following multi-stage successive reconnections s...

  3. Agminated blue nevus - Case report*

    Science.gov (United States)

    Lisboa, Alice Paixão; Silvestre, Keline Jácome; Pedreira, Renata Leite; Alves, Natália Ribeiro de Magalhães; Obadia, Daniel Lago; Azulay-Abulafia, Luna

    2016-01-01

    Blue nevi are benign melanocytic lesions located in the deeper reticular dermis, consequence of failure of melanocytic migration into the dermal-epidermal junction from the neural crest. Lesions are usually asymptomatic and solitary, but may present in a multiple or agminated (grouped) pattern. The agminated subtype is formed when bluish-pigmented lesions cluster together in a well-defined area. Lesions can be flat or raised. We report the case of a patient who presented multiple bluish macules (1-3 mm in diameter) grouped on the left upper back. Dermoscopy and anatomic pathological examination were consistent with blue nevus. PMID:27828645

  4. Frequency dependence of hysteretic magnetoimpedance in CoFeMoSiB amorphous ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Tejedor, M.; Hernando, B. E-mail: grande@pinon.ccu.uniovi.es; Sanchez, M.L.; Prida, V.M.; Kurlyandskaya, G.V.; Garcia, D.; Vazquez, M

    2000-06-02

    The hysteretic behaviour of the resistive and reactive components of the complex impedance at different frequencies in Co-based ribbons is presented. Sensitivities of the order of 1.2%/Am{sup -1} at 70 kHz for the reactive component of the MI and 0.63%/Am{sup -1} at 500 kHz for the resistive one were attained in the field range of 80-560 Am{sup -1}. The maximum relative ratio of MI was reached at 120 kHz with a sensitivity of 0.41%/Am{sup -1}.

  5. A new amorphous ribbon fluxgate sensor based on torsional-creep-induced anisotropy

    DEFF Research Database (Denmark)

    Nielsen, Otto V.; Gutierrez, J.; Hernando, B.

    1990-01-01

    The fluxgate sensor presented consists of a hairpin-shaped nonmagnetostrictive amorphous metal ribbon which carries the excitation AC current. Even harmonics are induced in a surrounding coil, which can be used both as a pickup coil and as a field compensation coil. The principle of operation...... is similar to that of a traditional ring-core system except that the core itself carries the excitation current. The sensor competes favorably with traditional fluxgate sensors with respect to simplicity, miniaturization, signal level, and noise level...

  6. Ribbon structure stabilized by C10 and C12 turns in αγ hybrid peptide.

    Science.gov (United States)

    Wani, Naiem Ahmad; Kant, Rajni; Gupta, Vivek Kumar; Aravinda, Subrayashastry; Rai, Rajkishor

    2016-04-01

    The present study describes the synthesis and crystallographic analysis of αγ hybrid peptides, Boc-Gpn-L-Pro-NHMe (1), Boc-Aib-Gpn-L-Pro-NHMe (2), and Boc-L-Pro-Aib-Gpn-L-Pro-NHMe (3). Peptides 1 and 2 adopt expanded 12-membered (C12 ) helical turn over γα segment. Peptide 3 promotes the ribbon structure stabilized by type II β-turn (C10 ) followed by the expanded C12 helical γα turn. Both right-handed and left-handed helical conformations for Aib residue are observed in peptides 2 and 3, respectively.

  7. Choice of copper-based alloys for ribbon substrates with a sharp cube texture

    Science.gov (United States)

    Khlebnikova, Yu. V.; Rodionov, D. P.; Gervas'eva, I. V.; Suaridze, T. R.; Akshentsev, Yu. N.; Kazantsev, V. A.

    2014-12-01

    It has been shown that, in some copper-based alloys subjected to cold deformation by rolling to 98.6-99% followed by recrystallization annealing, a sharp cube texture can be produced. Optimum conditions of annealing have been determined, which make it possible to produce a sharp biaxial texture in Cu-Ni, Cu-Fe, and Cu-Cr alloys with the fraction of cube grains of more than 95%; this opens a possibility of using thin ribbons made of these alloys as substrates for multilayer film compositions, in particular when developing second-generation high-temperature superconductors.

  8. Effect of increasing length on the electronic transport of an armchair graphene nano-ribbons

    Directory of Open Access Journals (Sweden)

    Sh Aghamiri Esfahani

    2015-12-01

    Full Text Available In this research, we have investigated the effect of increasing length on the electronic transport of an armchair graphene nano-ribbons with nitrogen atom impurity and without impurity. The semi-infinite, one-dimensional molecular systems are connected to two electrodes and the electron-electron interaction is ignored. The system is described by a simple tight binding model. All calculations are based on the Green's function and Landauer–Buttiker approach, and the electrodes are described in a wide band approximation.

  9. Filtering characteristics of a graphene ribbon with a rectangle ring in infrared region

    Directory of Open Access Journals (Sweden)

    Yueke Wang

    2016-11-01

    Full Text Available We propose a structure of a graphene ribbon with a rectangle ring, which is deposited on SiO2 substrate. Our simulation results, conducted by finite element method, show that the transmission dips originate from the ring resonance of the fundamental edge graphene plasmons mode. By choosing specific parameters, the transmission dips of 6th and 4th order ring resonances can split into two, respectively, due to corner effect. Thanks to tunable permittivity of graphene by gate voltages, active control of filtering window is achieved. It is believed that our findings provide a smart way to design a tunable multiple window filter at infrared region.

  10. "Task" as Research Construct

    Science.gov (United States)

    Seedhouse, Paul

    2005-01-01

    The article examines "task" as research construct as predominantly conceived in terms of task-as-workplan in the task-based learning/second language acquisition literature. It is suggested that "task" has weak construct validity and ontology in an overwhelmingly quantitative paradigm because the construct has a "split personality."…

  11. Fabrication of Ni-decorated helical ribbon composite microstructure from self-assembled lipid tubule by electroless metallization

    Institute of Scientific and Technical Information of China (English)

    FU Yubin; ZHANG Lide; ZHENG Jiyong

    2006-01-01

    Lipid molecules can self-assemble into a tubular structure, which is formed by tightly wound helical ribbons. Lipid tubules are utilized as a precursor to fabricate a novel Ni-decorated helical ribbon composite microstructure in a high yield by electroless deposition. The microstructure carries Ni nanoparticles on the flat face and wires at the edge of helical ribbon, in which the average size of nanoparticles is about 40-60 nm, and the wires are of a layered structure strongly correlated with a multi-bilayer structure in the lipid membrane. Compared with the tubular precursor, the Ni-decorated composite microstructure becomes short and irregular shapes due to the breakage in the deposition, and its formation is largely bound up with the tubular helical structure and the different catalytic process. Finally, the helical composite microstructure would have a potential application in the development of electric active materials.

  12. Effects of quenching speed and Joule heating on the magnetic properties of Nd9Fe86B5 ribbons

    Institute of Scientific and Technical Information of China (English)

    AN Kang; HU Jifan; WANG Dongling; QIN Hongwei; SUN Guangfei; CHEN Jufang; YU Xiaojun; LI Bo

    2005-01-01

    The influences of quenching speed and current annealing on the magnetic properties of Nd9Fe86B5 ribbons were investigated. There is an optimum quenching speed (v ≈ 15 m/s) for preparing hard magnetic ribbons, where the remanence of 1.22 T, the intrinsic coercivity of 521 kA.m1 and the energy products of 150 kJ.m-3 are obtained. After annealing ribbons prepared with v = 20 m/s at a dc current of 0.85 A, the remanence reaches a quite large value of 1.47 T, which attributes to the strong exchange coupling interactions between the fine grains of Nd2Fe14B and α-Fe.

  13. Effect of Fe on the Martensitic Transition, Magnetic and Magnetocaloric Properties in Ni-Mn-In Melt-spun Ribbons

    Directory of Open Access Journals (Sweden)

    D.M. Raj kumar

    2016-06-01

    Full Text Available The effect of Fe on the martensitic transitions, magnetic and inverse magnetocaloric effect in Ni47Mn40-xFexIn13 ribbons (x = 1, 2, 3 and 5 has been investigated. All the ribbon compositions under study have shown the presence of austenite phase at room temperature. The variation of martensitic transition with the increase in Fe-content is non-monotonic. The thermal hysteresis of the martensitic transition increased with the increase in Fe-content. The martensitic transitions shifted to lower temperatures in the presence of high magnetic fields. A maximum magnetic entropy change (∆SM of 50 Jkg-1K-1 has been achieved in the Ni47Mn38Fe2In13 (x = 1 ribbon at 282 K for an applied field of 5 T.

  14. Martensitic transformation in rapidly solidified Heusler Ni{sub 49}Mn{sub 39}Sn{sub 12} ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Hongxing, E-mail: hxzheng@shu.edu.cn [Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China); Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, Shanghai 200072 (China); Wu Dianzhen; Xue Sichuang [Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China); Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, Shanghai 200072 (China); Frenzel, Jan; Eggeler, Gunther [Institute of Materials, Ruhr University Bochum, Bochum 44801 (Germany); Zhai Qijie [Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, Shanghai 200072 (China)

    2011-08-15

    In the present work, the microstructure evolution and kinetics of the martensitic transformation are investigated in as-spun and annealed ribbons of Heusler Ni{sub 49}Mn{sub 39}Sn{sub 12} using electron microscopy, X-ray diffraction and differential scanning calorimetry. Both ribbons undergo a reversible martensitic transformation during thermal cycling and the low-temperature martensite is confirmed to be a modulated four-layered orthorhombic (4O) structure through in situ cooling transmission electronic microscopy investigation. The annealing effect on the martensitic transformation behavior is discussed from the viewpoints of electron concentration, Mn-Mn interatomic distance, atomic order degree and grain size. A strong cooling-rate dependence of phase transition kinetics is found and the mechanism is analyzed. The satisfactory reproducibility obtained during thermal cycling test of this alloy ribbons offers great potential for practical applications.

  15. Blue Ocean vs. Five Forces

    NARCIS (Netherlands)

    A.E. Burke (Andrew); A.J. van Stel (André); A.R. Thurik (Roy)

    2010-01-01

    textabstractThe article reports on the authors' research in the Netherlands which focused on a profit model in Dutch retail stores and a so-called blue-ocean approach which requires a new market that attracts consumers and increases profits. Topics include the competitive strategy approach to increa

  16. Blue rubber bleb naevus syndrome

    DEFF Research Database (Denmark)

    Lybecker, Martin Bell; Stawowy, Marek; Clausen, Niels

    2016-01-01

    Blue rubber bleb naevus syndrome (BRBNS) is a rare vascular disorder with malformed veins, or blebs, appearing in the skin or internal organs. Gastrointestinal tract involvement is the most common feature and often subject to bleeding, potentially resulting in chronic occult blood loss and iron...

  17. The blue revolution in asia

    DEFF Research Database (Denmark)

    Jespersen, Karen Sau; Ponte, Stefano; Kelling, Ingrid

    2014-01-01

    In this article, we examine the upgrading trajectories of selected aquaculture value chains in four Asian countries and the links between upgrading and three factors of value chain governance: coordination mechanisms; types of drivers; and domestic regulation. We find instances of improving produ...... of upgrading the "blue revolution" in Asia...

  18. Evolution of flare ribbons, electric currents, and quasi-separatrix layers during an X-class flare

    Science.gov (United States)

    Janvier, M.; Savcheva, A.; Pariat, E.; Tassev, S.; Millholland, S.; Bommier, V.; McCauley, P.; McKillop, S.; Dougan, F.

    2016-07-01

    Context. The standard model for eruptive flares has been extended to three dimensions (3D) in the past few years. This model predicts typical J-shaped photospheric footprints of the coronal current layer, forming at similar locations as the quasi-separatrix layers (QSLs). Such a morphology is also found for flare ribbons observed in the extreme ultraviolet (EUV) band, and in nonlinear force-free field (NLFFF) magnetic field extrapolations and models. Aims: We study the evolution of the photospheric traces of the current density and flare ribbons, both obtained with the Solar Dynamics Observatory instruments. We aim to compare their morphology and their time evolution, before and during the flare, with the topological features found in a NLFFF model. Methods: We investigated the photospheric current evolution during the 06 September 2011 X-class flare (SOL2011-09-06T22:20) occurring in NOAA AR 11283 from observational data of the magnetic field obtained with the Helioseismic and Magnetic Imager aboard the Solar Dynamics Observatory. We compared this evolution with that of the flare ribbons observed in the EUV filters of the Atmospheric Imager Assembly. We also compared the observed electric current density and the flare ribbon morphology with that of the QSLs computed from the flux rope insertion method-NLFFF model. Results: The NLFFF model shows the presence of a fan-spine configuration of overlying field lines, due to the presence of a parasitic polarity, embedding an elongated flux rope that appears in the observations as two parts of a filament. The QSL signatures of the fan configuration appear as a circular flare ribbon that encircles the J-shaped ribbons related to the filament ejection. The QSLs, evolved via a magnetofrictional method, also show similar morphology and evolution as both the current ribbons and the EUV flare ribbons obtained several times during the flare. Conclusions: For the first time, we propose a combined analysis of the photospheric

  19. The Homotopic Probability Distribution and the Partition Function for the Entangled System Around a Ribbon Segment Chain

    Institute of Scientific and Technical Information of China (English)

    QIAN Shang-Wu; GU Zhi-Yu

    2001-01-01

    Using the Feynman's path integral with topological constraints arising from the presence of one singular line, we find the homotopic probability distribution PnL for the winding number n and the partition function PL of the entangled system around a ribbon segment chain. We find that when the width of the ribbon segment chain 2a increases,the partition function exponentially decreases, whereas the free energy increases an amount, which is proportional to the square of the width. When the width tends to zero we obtain the same results as those of a single chain with one singular point.

  20. Evidence of microstructures and fluid inclusions for the origin of polycrystalline quartz ribbons in high-grade metamorphic rocks in Daqingshan resion

    Institute of Scientific and Technical Information of China (English)

    LIU ZhengHong; XU ZhongYuan; WANG KeYong

    2007-01-01

    Polycrystalline quartz ribbons in high-grade metamorphic rocks from the Daqingshan region, are typical microfabrics of, and provide information for, deep crust deformation and metamorphism. The quartz ribbons have straight boundaries and extend stably along gneissosity. They truncate other mineral grains in the rocks and may contain inclusions of such minerals that are lens-shaped and oriented. They frequently end into branching termination. Analysis fluid inclusions in polycrystalline quartz ribbons reveal that the complex types of fluid inclusions are inhomogeneously distributed. They are obviously different from inclusions captured at granulite facies, in both fluid compositions and T-P estimations. Based on microfabric and fluid inclusion analysis, the polycrystalline quartz ribbons are suggested to be formed by SO2-rich fluids filling micro-fractures that are parallel to early gneissosity. The SO2 composition is derived from the deformed host rocks. The fluid phase has significant effects on the rheological characteristics, fracturing of rocks, and formation of quartz ribbons.

  1. Recalling academic tasks

    Science.gov (United States)

    Draper, Franklin Gno

    This study was focused on what students remembered about five middle school science tasks when they were juniors and seniors in high school. Descriptions of the five tasks were reconstructed from available artifacts and teachers' records, notes and recollections. Three of the five tasks were "authentic" in the sense that students were asked to duplicate the decisions practitioners make in the adult world. The other two tasks were more typical school tasks involving note taking and preparation for a quiz. All five tasks, however, involved use of computers. Students were interviewed to examine what and how well they recalled the tasks and what forms or patterns of recall existed. Analysis of their responses indicated that different kinds of tasks produced different levels of recall. Authentically situated tasks were remembered much better than routine school tasks. Further, authentic tasks centered on design elements were recalled better than those for which design was not as pivotal. Patterns of recall indicated that participants most often recalled the decisions they made, the scenarios of the authentically situated tasks, the consequences of their tasks and the social contexts of the classroom. Task events, in other words, appeared to form a framework upon which students constructed stories of the tasks. The more salient the events, the richer the story, the deeper and more detailed the recall of the task. Thus, authentic tasks appeared to lend themselves to creating stories better than regular school tasks and therefore such tasks were recalled better. Implications of these patterns of recall are discussed with respect to issues of school learning and assessment.

  2. TEMPORAL EVOLUTION OF MULTIPLE EVAPORATING RIBBON SOURCES IN A SOLAR FLARE

    Energy Technology Data Exchange (ETDEWEB)

    Graham, D. R.; Cauzzi, G., E-mail: dgraham@arcetri.astro.it [INAF-Osservatorio Astrofisico di Arcetri, I-50125 Firenze (Italy)

    2015-07-10

    We present new results from the Interface Region Imaging Spectrograph (IRIS) showing the dynamic evolution of chromospheric evaporation and condensation in a flare ribbon, with the highest temporal and spatial resolution to date. IRIS observed the entire impulsive phase of the X-class flare SOL2014-09-10T17:45 using a 9.4 s cadence “sit-and-stare” mode. As the ribbon brightened successively at new positions along the slit, a unique impulsive phase evolution was observed for many tens of individual pixels in both coronal and chromospheric lines. Each activation of a new footpoint displays the same initial coronal upflows of up to ∼300 km s{sup −1} and chromospheric downflows up to 40 km s{sup −1}. Although the coronal flows can be delayed by over 1 minute with respect to those in the chromosphere, the temporal evolution of flows is strikingly similar between all pixels and consistent with predictions from hydrodynamic flare models. Given the large sample of independent footpoints, we conclude that each flaring pixel can be considered a prototypical, “elementary” flare kernel.

  3. Electric current in flares ribbons: from the standard model in 3D to observations

    CERN Document Server

    Janvier, Miho; Bommier, V; Schmieder, B; Démoulin, P; Pariat, E

    2014-01-01

    The paper presents for the first time a quantification of the photospheric electric current ribbon evolutions during an eruptive flare, accurately predicted by the standard 3D flare model. The standard flare model in 3D has been developed with the MHD code OHM, which models the evolution of an unstable flux rope. Through a series of paper, the model has been successful in explaining observational characteristics of eruptive flares, as well as the intrinsic 3D reconnection mechanism. Such a model also explains the increase of the photospheric currents as a consequence of the evolution of the coronal current layer where reconnection takes place. The photospheric footprints of the 3D current layer reveal a ribbon shape structure. In the present paper, the evolution of the current density is analyzed for the X-class flare that occurred on 15/02/2011 in AR 11158. We first describe the structural evolution of the high vertical current density regions derived with the UNNOFIT inversion code from magnetograms (HMI, e...

  4. Two modes of release shape the postsynaptic response at the inner hair cell ribbon synapse.

    Science.gov (United States)

    Grant, Lisa; Yi, Eunyoung; Glowatzki, Elisabeth

    2010-03-24

    Cochlear inner hair cells (IHCs) convert sounds into receptor potentials and via their ribbon synapses into firing rates in auditory nerve fibers. Multivesicular release at individual IHC ribbon synapses activates AMPA-mediated EPSCs with widely ranging amplitudes. The underlying mechanisms and specific role for multivesicular release in encoding sound are not well understood. Here we characterize the waveforms of individual EPSCs recorded from afferent boutons contacting IHCs and compare their characteristics in immature rats (postnatal days 8-11) and hearing rats (postnatal days 19-21). Two types of EPSC waveforms were found in every recording: monophasic EPSCs, with sharp rising phases and monoexponential decays, and multiphasic EPSCs, exhibiting inflections on rising and decaying phases. Multiphasic EPSCs exhibited slower rise times and smaller amplitudes than monophasic EPSCs. Both types of EPSCs had comparable charge transfers, suggesting that they were activated by the release of similar numbers of vesicles, which for multiphasic EPSCs occurred in a less coordinated manner. On average, a higher proportion of larger, monophasic EPSCs was found in hearing compared to immature rats. In addition, EPSCs became significantly faster with age. The developmental increase in size and speed could improve auditory signaling acuity. Multiphasic EPSCs persisted in hearing animals, in some fibers constituting half of the EPSCs. The proportion of monophasic versus multiphasic EPSCs varied widely across fibers, resulting in marked heterogeneity of amplitude distributions. We propose that the relative contribution of two modes of multivesicular release, generating monophasic and multiphasic EPSCs, may underlie fundamental characteristics of auditory nerve fibers.

  5. Field Investigations On the Lateral Vibration Features Of Prestressed Concrete Stress Ribbon Footbridges

    Directory of Open Access Journals (Sweden)

    Fukada Saiji

    2015-01-01

    Full Text Available The prestressed concrete (PC stress ribbon footbridge is a type of suspension bridge without towers, which has been applied in Japan and all over the world for years in light of its low construction cost and aesthetic merit. It generally consists of the precast concrete slabs with embedded cables. However, the walking-induced lateral vibration trouble of the Millennium Bridge in London in 2000 gave a lesson to the engineers that the lateral vibration feature must be taken into consideration for the footbridge vibration evaluation. In this sense, the field investigations on the lateral vibration features of 14 pre-stressed concrete stress ribbon footbridge in Japan was carried out by artificial impact and damping free vibration tests. According to the investigations, the larger the bridge span, the lower the frequencies of lateral-related vibration modes. In addition, based on the damping-free vibration field tests, there was a tendency toward the damping constant degradation when bridge span became larger.

  6. Graphene nano-ribbon with nano-breaks as efficient thermoelectric device

    Science.gov (United States)

    Hossain, Md Sharafat; Al-Dirini, Feras; Jiang, Liming; Hossain, Faruque M.; Skafidas, Efstratios

    2015-12-01

    It has been well established that delta-like transport distribution of electron gives the best thermoelectric performance. On another front, it has been experimentally verified that graphene nano-ribbon with nano-break in the channel region exhibits tunnelling. Here, we utilize the tunnelling phenomena observed in graphene break junctions to achieve delta like transport distribution. Indeed our device exhibit record ZT ranging from 10 to 100. This high ZT can be attributed to complete blockage of phonon transport due to the break. The electrical conductance also goes very low, however, near the tunnelling energy it becomes significant, giving rise to an enhanced ZT value. In this report we investigate the effect edge orientation and the width of the ribbon on thermoelectric property. Moreover, we investigate the effect of temperature on tunnelling and how it affect thermoelectric performance. We find that there is an optimal temperature at which the device performs best. In the simulations, we assumed ballistic transport and used first principle approach to obtain the electrical properties. The phononic system was characterized by a Tersoff empirical potential model. The proposed device structure has potential applications as a two-dimensional nanoscale local cooler and as a thermoelectric power generator when connected in arrays.

  7. Rotating Magnetic Structures Associated with a Quasi-circular Ribbon Flare

    Science.gov (United States)

    Li, Haidong; Jiang, Yunchun; Yang, Jiayan; Yang, Bo; Xu, Zhe; Hong, Junchao; Bi, Yi

    2017-02-01

    We present the detection of a small eruption and the associated quasi-circular ribbon flare during the emergence of a bipole occurring on 2015 February 3. Under a fan dome, a sigmoid was rooted in a single magnetic bipole, which was encircled by negative polarity. The nonlinear force-free field extrapolation shows the presence of twisted field lines, which can represent a sigmoid structure. The rotation of the magnetic bipole may cause the twisting of magnetic field lines. An initial brightening appeared at one of the footpoints of the sigmoid, where the positive polarity slides toward a nearby negative polarity field region. The sigmoid displayed an ascending motion and then interacted intensively with the spine-like field. This type of null point reconnection in corona led to a violent blowout jet, and a quasi-circular flare ribbon was also produced. The magnetic emergence and rotational motion are the main contributors to the energy buildup for the flare, while the cancellation and collision might act as a trigger.

  8. Martensitic transformation and magnetic properties of Heusler alloy Ni-Fe-Ga ribbon

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Z.H. [Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)]. E-mail: zhliu@aphy.iphy.ac.cn; Liu, H. [Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China); Zhang, X.X. [Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China); Zhang, M. [State Key Laboratory for Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Dai, X.F. [State Key Laboratory for Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Hu, H.N. [State Key Laboratory for Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Chen, J.L. [State Key Laboratory for Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Wu, G.H. [State Key Laboratory for Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)]. E-mail: userm201@aphy.iphy.ac.cn

    2004-08-23

    The martensitic transformation and magnetic properties of ferromagnetic shape memory alloy Ni{sub 50+x}Fe{sub 25-x}Ga{sub 25} (x=-1, 0, 1, 2, 3, 4) ribbons have been systematically studied. It has been found that with the increase of Ni concentration, the martensitic transformation temperature increases, but the Curie temperature decreases. Both the two-step thermally induced structural transformation and the one-step transition have been observed in NiFeGa alloys with different compositions. It is found that the two-step transition became the one-step transition after the ribbon being heat treated at 873 K or higher. X-ray diffraction patterns show that only L21->B2 transition occurs in the samples treated at 873 K, while the {gamma} phase will form in the samples treated at higher temperature. Transmission electron microscopy (TEM) studies show that the alloys with martensitic transformation temperature above the room temperature are non-modulated martensite with the large domain size, being different from the stoichiometric Ni{sub 2}FeGa alloy that is a modulated martensite with small domain size. The influences of Fe substitution for Ni in Ni{sub 2}FeGa on the saturation magnetization and exchange interaction are also discussed.

  9. Assessment of energetic neutral He atom intensities expected from the IBEX Ribbon

    CERN Document Server

    Swaczyna, P; Bzowski, M

    2014-01-01

    Full sky maps of energetic neutral atoms (ENA) obtained with the Interstellar Boundary Explorer revealed a bright, arc-like Ribbon. We compare possible, thought as yet undetected, He ENA emission in two models of the Ribbon origin. The models were originally developed for hydrogen ENA. In the first one, ENA are produced outside the heliopause from the ionized neutral solar wind in the direction where the local interstellar magnetic field is perpendicular to the line-of-sight. The second model proposes production at the interface between the Local Interstellar Cloud (LIC) and the Local Bubble (LB). The models are redesigned to helium using relevant interactions between atoms and ions. Resulting intensities are compared with possible emission of helium ENA from the heliosheath. In the first model, expected intensity is ~ 0.014 (cm^2 s sr keV)^-1, i.e., of the order of the He emission from the heliosheath, whereas in the second, the LIC/LB interface model, the intensity is ~ (2 - 7) (cm^2 s sr keV)^-1, i.e., a f...

  10. Local Interstellar Magnetic Field Determined from the Interstellar Boundary Explorer Ribbon

    Science.gov (United States)

    Zirnstein, E. J.; Heerikhuisen, J.; Funsten, H. O.; Livadiotis, G.; McComas, D. J.; Pogorelov, N. V.

    2016-02-01

    The solar wind emanating from the Sun interacts with the local interstellar medium (LISM), forming the heliosphere. Hydrogen energetic neutral atoms (ENAs) produced by the solar-interstellar interaction carry important information about plasma properties from the boundaries of the heliosphere, and are currently being measured by NASA's Interstellar Boundary Explorer (IBEX). IBEX observations show the existence of a “ribbon” of intense ENA emission projecting a circle on the celestial sphere that is centered near the local interstellar magnetic field (ISMF) vector. Here we show that the source of the IBEX ribbon as a function of ENA energy outside the heliosphere, uniquely coupled to the draping of the ISMF around the heliopause, can be used to precisely determine the magnitude (2.93 ± 0.08 μG) and direction (227.°28 ± 0.°69, 34.°62 ± 0.°45 in ecliptic longitude and latitude) of the pristine ISMF far (∼1000 AU) from the Sun. We find that the ISMF vector is offset from the ribbon center by ∼8.°3 toward the direction of motion of the heliosphere through the LISM, and their vectors form a plane that is consistent with the direction of deflected interstellar neutral hydrogen, thought to be controlled by the ISMF. Our results yield draped ISMF properties close to that observed by Voyager 1, the only spacecraft to directly measure the ISMF close to the heliosphere, and give predictions of the pristine ISMF that Voyager 1 has yet to sample.

  11. Temporal evolution of multiple evaporating ribbon sources in a solar flare

    CERN Document Server

    Graham, D R

    2015-01-01

    We present new results from the Interface Region Imaging Spectrograph showing the dynamic evolution of chromospheric evaporation and condensation in a flare ribbon, with the highest temporal and spatial resolution to date. IRIS observed the entire impulsive phase of the X-class flare SOL2014-09-10T17:45 using a 9.4 second cadence `sit-and-stare' mode. As the ribbon brightened successively at new positions along the slit, a unique impulsive phase evolution was observed for many tens of individual pixels in both coronal and chromospheric lines. Each activation of a new footpoint displays the same initial coronal up-flows of up to ~300 km/s, and chromospheric downflows up to 40 km/s. Although the coronal flows can be delayed by over 1 minute with respect to those in the chromosphere, the temporal evolution of flows is strikingly similar between all pixels, and consistent with predictions from hydrodynamic flare models. Given the large sample of independent footpoints, we conclude that each flaring pixel can be c...

  12. Magnetization Dynamics of Amorphous Ribbons and Wires Studied by Inductance Spectroscopy

    Directory of Open Access Journals (Sweden)

    Israel Betancourt

    2010-12-01

    Full Text Available Inductance spectroscopy is a particular formulation variant of the well known complex impedance formalism typically used for the electric characterization of dielectric, ferroelectric, and piezoelectric materials. It has been successfully exploited as a versatile tool for characterization of the magnetization dynamics in amorphous ribbons and wires by means of simple experiments involving coils for sample holding and impedance analyzer equipment. This technique affords the resolution of the magnetization processes in soft magnetic materials, in terms of reversible deformation of pinned domain walls, domain wall displacements and spin rotation, for which characteristic parameters such as the alloy initial permeability and the relaxation frequencies, indicating the dispersion of each process, can be defined. Additionally, these parameters can be correlated with chemical composition variation, size effects and induced anisotropies, leading to a more physical insight for the understanding of the frequency dependent magnetic response of amorphous alloys, which is of prime interest for the development of novel applications in the field of telecommunication and sensing technologies. In this work, a brief overview, together with recent progress on the magnetization dynamics of amorphous ribbons, wires, microwires and biphase wires, is presented and discussed for the intermediate frequency interval between 10 Hz and 13 MHz.

  13. Study of Critical Behavior in Amorphous Fe85Sn5Zr10 Alloy Ribbon

    Science.gov (United States)

    Han, L. A.; Hua, X. H.; Zhu, H. Z.; Yang, J.; Yang, H. P.; Yan, Z. X.; Zhang, T.

    2016-10-01

    We have investigated the critical behavior in amorphous Fe85Sn5Zr10 alloy ribbon prepared using a single-roller melt-spinning method. This alloy shows a second-order magnetic transition from paramagnetic to ferromagnetic (FM) state at the Curie temperature T C (˜306 K). To obtain more information on the features of the magnetic transition, a detailed critical exponent study was carried out using isothermal magnetization M (H, T) data in the vicinity of the T C. Modified Arrott plot, Kouvel-Fisher plot, Widom's scaling relation and critical isotherm analysis techniques were used to investigate the critical behavior of this alloy system around its phase transition point. The values of critical exponents determined using the above methods are self-consistent. The estimated critical exponents are fairly close to the theoretical prediction of the three-dimensional (3D) Heisenberg model, implying that short-range FM interactions dominate the critical behavior in amorphous Fe85Sn5Zr10 alloy ribbon.

  14. Epitaxial diamond-hexagonal silicon nano-ribbon growth on (001) silicon

    Science.gov (United States)

    Qiu, Y.; Bender, H.; Richard, O.; Kim, M.-S.; van Besien, E.; Vos, I.; de Potter de Ten Broeck, M.; Mocuta, D.; Vandervorst, W.

    2015-08-01

    Silicon crystallizes in the diamond-cubic phase and shows only a weak emission at 1.1 eV. Diamond-hexagonal silicon however has an indirect bandgap at 1.5 eV and has therefore potential for application in opto-electronic devices. Here we discuss a method based on advanced silicon device processing to form diamond-hexagonal silicon nano-ribbons. With an appropriate temperature anneal applied to densify the oxide fillings between silicon fins, the lateral outward stress exerted on fins sandwiched between wide and narrow oxide windows can result in a phase transition from diamond-cubic to diamond-hexagonal Si at the base of these fins. The diamond-hexagonal slabs are generally 5-8 nm thick and can extend over the full width and length of the fins, i.e. have a nano-ribbon shape along the fins. Although hexagonal silicon is a metastable phase, once formed it is found being stable during subsequent high temperature treatments even during process steps up to 1050 ºC.

  15. Imaging Observations of Quasi-Periodic Pulsatory Non-Thermal Emission in Ribbon Solar Flares

    CERN Document Server

    Zimovets, I V

    2008-01-01

    Using RHESSI and some auxiliary observations we examine possible connections between spatial and temporal morphology of the sources of non-thermal hard X-ray (HXR) emission which revealed minute quasi-periodic pulsations (QPPs) during the two-ribbon flares on 2003 May 29 and 2005 January 19. Microwave emission also reveals the same quasi-periodicity. The sources of non-thermal HXR emission are situated mainly inside the footpoints of the flare arcade loops observed by the TRACE and SOHO instruments. At least one of the sources moves systematically both during the QPP-phase and after it in each flare that allows to examine the sources velocities and the energy release rate via the process of magnetic reconnection. The sources move predominantly parallel to the magnetic inversion line or the appropriate flare ribbon during the QPP-phase whereas the movement slightly changes to more perpendicular regime after the QPPs. Each QPP is emitted from its own position. It is also seen that the velocity and the energy re...

  16. Investigation of the effect of rapidly solidified braze ribbons on the microstructure of brazed joints

    Science.gov (United States)

    Bobzin, K.; Öte, M.; Wiesner, S.; Rochala, P.; Mayer, J.; Aretz, A.; Iskandar, R.; Schwedt, A.

    2017-03-01

    Shrinkage and warpage due to melting and solidification are crucial for the geometric precision of related components. In order to assure a high geometric precision, the formation of the microstructure in the joint during brazing must be taken into consideration. An extensive interaction can occur between liquid melt and base material, resulting in the formation of distinctive phases. This interaction depends on the parameters of the brazing process. However, the consequences of the interaction between phase formation and process parameters in terms of geometric precision cannot be estimated yet. Insufficient quality of the joint can be a result. In this study, investigations focus on the process of solidification in terms of time dependent diffusion behavior of elements. Therefore, microcrystalline and amorphous braze ribbons based on Ti are produced by rapid solidification and are used for joining. The microstructure of the braze ribbons as well as the melting behavior and phase formation during brazing are considered to be of particular importance for the mechanical properties of the brazed components.

  17. Study of Critical Behavior in Amorphous Fe85Sn5Zr10 Alloy Ribbon

    Science.gov (United States)

    Han, L. A.; Hua, X. H.; Zhu, H. Z.; Yang, J.; Yang, H. P.; Yan, Z. X.; Zhang, T.

    2017-02-01

    We have investigated the critical behavior in amorphous Fe85Sn5Zr10 alloy ribbon prepared using a single-roller melt-spinning method. This alloy shows a second-order magnetic transition from paramagnetic to ferromagnetic (FM) state at the Curie temperature T C (˜306 K). To obtain more information on the features of the magnetic transition, a detailed critical exponent study was carried out using isothermal magnetization M ( H, T) data in the vicinity of the T C. Modified Arrott plot, Kouvel-Fisher plot, Widom's scaling relation and critical isotherm analysis techniques were used to investigate the critical behavior of this alloy system around its phase transition point. The values of critical exponents determined using the above methods are self-consistent. The estimated critical exponents are fairly close to the theoretical prediction of the three-dimensional (3D) Heisenberg model, implying that short-range FM interactions dominate the critical behavior in amorphous Fe85Sn5Zr10 alloy ribbon.

  18. Structural and magnetic studies of the nanocrystalline Nd-Fe-B-Nb alloy ribbons

    Directory of Open Access Journals (Sweden)

    Gębara P.

    2013-01-01

    Full Text Available A detailed studies of the phase constitution, microstructure and magnetic properties of the nanocrystalline Nd9.2Fe61.64B21.16Nb8 alloy ribbons, are reported. It was shown that the rapidly solidified ribbons have partially amorphous structure and soft magnetic properties in the as-cast state. The heat treatment at temperatures higher than 923 K led to the growth of the hard magnetic Nd2Fe14B phase and the metastable Nd2Fe23B3 phase. The Mössbauer confirmed that during annealing of the samples at temperature higher than 923 K the paramagnetic Nd1+εFe4B4 phase was also formed. The microstructure consisting of mixture of constituent phases was observed with transmission electron microscopy (TEM. Furthermore, with increasing annealing temperature the decrease of the saturation polarization Js was observed. The maximum values of coercivity JHc = 1175 kA/m was obtained for a sample annealed at 1023K. However, annealing at 1003 K resulted in the improvement of remanence polarization Jr = 0.35 T and the maximum energy product (BHmax = 21 kJ/m3.

  19. Microstructural study of the crystallization of amorphous Fe–Sn–B ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Maťko, Igor, E-mail: igor.matko@savba.sk [Institute of Physics, Slovak Academy of Sciences, Dúbravska cesta 9, 845 11 Bratislava (Slovakia); Illeková, Emília; Peter Švec Sr; Švec, Peter; Janičkovič, Dušan [Institute of Physics, Slovak Academy of Sciences, Dúbravska cesta 9, 845 11 Bratislava (Slovakia); Vodárek, Vlastimil [VŠB-Technical University of Ostrava, Department of Materials Engineering, 708 33 Ostrava-Poruba (Czech Republic)

    2014-12-05

    Highlights: • Amorphous Fe{sub 78}Sn{sub 5}B{sub 17} ribbons were prepared by planar flow casting. • Crystallization was studied by thermal analysis, XRD and TEM. • The crystallization begins by formation of specific nanocrystalline Fe(Sn) phase. • Role of Sn in formation of the nanocrystalline phase is discussed. • Next step of the crystallization corresponding to complex process is also analysed. - Abstract: Amorphous Fe{sub 78}Sn{sub 5}B{sub 17} ribbons were prepared by planar flow casting. The thermodynamic stability and the kinetics of observed phase transformations were monitored by thermal analysis. The structure and morphology of phases forming upon the thermally activated crystallization is studied by X-ray diffraction and transmission electron microscopy. The crystallization begins by nucleation-and-growth of specific nanocrystalline bcc-Fe(Sn) phase, its structure is explored more in details and the role of Sn in its formation is discussed. In the next step of the crystallization a transformation of remaining amorphous matrix to iron borides runs via rather complex process, which is inspected more in details as well.

  20. Novel hydrated graphene ribbon unexpectedly promotes aged seed germination and root differentiation.

    Science.gov (United States)

    Hu, Xiangang; Zhou, Qixing

    2014-01-21

    It is well known that graphene (G) induces nanotoxicity towards living organisms. Here, a novel and biocompatible hydrated graphene ribbon (HGR) unexpectedly promoted aged (two years) seed germination. HGR formed at the normal temperature and pressure (120 days hydration), presented 17.1% oxygen, 0.9% nitrogen groups, disorder-layer structure, with 0.38 nm thickness ribbon morphology. Interestingly, there were bulges around the edges of HGR. Compared to G and graphene oxide (GO), HGR increased seed germination by 15% root differentiation between 52 and 59% and enhanced resistance to oxidative stress. The metabonomics analysis discovered that HGR upregulated carbohydrate, amino acid, and fatty acids metabolism that determined secondary metabolism, nitrogen sequestration, cell membrane integrity, permeability, and oxidation resistance. Hexadecanoic acid as a biomarker promoted root differentiation and increased the germination rate. Our discovery is a novel HGR that promotes aged seed germination, illustrates metabolic specificity among graphene-based materials, and inspires innovative concepts in the regulation of seed development.

  1. Short-range ferromagnetism in alloy ribbons of Fe-Cr-Si-Nb-(Ag, Cu)

    Energy Technology Data Exchange (ETDEWEB)

    THANH, P. Q.; HOA, N. Q.; CHAU, N. [Vietnam National University, Hanoi (Viet Nam); HUU, C. X. [Danang University of Technology, Danang (Viet Nam); NGO, D. T. [Technical University of Denmark, Kgs. Lyngby (Denmark); PHAN, T. L. [Chungbuk National University, Cheongju (Korea, Republic of)

    2014-04-15

    We have studied the magnetic properties of two amorphous alloy ribbons Fe{sub 72}Cr{sub 6}Si{sub 4}Nb{sub 5}B{sub 12}Ag{sub 1} (FCSNB-Ag) and Fe{sub 72}Cr{sub 6}Si{sub 4}Nb{sub 5}B{sub 12}Cu{sub 1} (FCSNB-Cu), prepared by using a melt-spinning technique. Magnetization (M) measurements for various temperatures (T) and magnetic fields (H) indicate that ferromagnetic-paramagnetic (FM-PM) phase transitions take place in FCSNB-Ag and FCSNB-Cu at Curie temperatures (T{sub C} ) of about 308.3 K and 322.5 K, respectively. Analyses of M - H data at different temperatures in the vicinity of the FM-PM phase transition based on the modified Arrott plot method and scaling hypothesis yielded the exponent values of β = 0.369 ± 0.005, γ = 1.359 ± 0.005 and δ = 4.7 ± 0.1 for FCSNB-Ag, and β = 0.376 ± 0.002, γ = 1.315 ± 0.006 and δ = 4.5 ± 0.1 for FCSNB-Cu. Compared with the values from theoretical models, these values are close to those expected for the 3D Heisenberg model, demonstrating the existence of short-range FM order in the amorphous alloy ribbons.

  2. Ribbons characterize magnetohydrodynamic magnetic fields better than lines: a lesson from dynamo theory

    CERN Document Server

    Blackman, Eric G

    2014-01-01

    Blackman & Brandenburg argued that magnetic helicity conservation in dynamo theory can in principle be captured by diagrams of mean field dynamos when the magnetic fields are represented by ribbons or tubes, but not by lines. Here we present such a schematic ribbon diagram for the $\\alpha^2$ dynamo that tracks magnetic helicity and provides distinct scales of large scale magnetic helicity, small scale magnetic helicity, and kinetic helicity involved in the process. This also motivates our construction of a new ``2.5 scale'' minimalist generalization of the helicity-evolving equations for the \\alpha^2 dynamo that separately allows for these three distinct length scales while keeping only two dynamical equations. We solve these equations and, as in previous studies, find that the large scale field first grows at a rate independent of the magnetic Reynolds number R_M before quenching to an R_M dependent regime. But we also show that the larger the ratio of the wavenumber where the small scale current helicit...

  3. QCD-inspired spectra from Blue`s functions

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, M.A. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)]|[Technische Hochschule Darmstadt (Germany). Inst. fuer Kernphysik]|[Uniwersytet Jagiellonski, Cracow (Poland). Dept. of Theoretical Physics; Papp, G. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)]|[Lorand Eoetvoes Univ., Budapest (Hungary). Inst. for Theoretical Physics; Zahed, I. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics

    1996-03-01

    We use the law of addition in random matrix theory to analyze the spectral distributions of a variety of chiral random matrix models as inspired from QCD whether by symmetries or models. In terms of the Blue`s functions recently discussed by Zee, we show that most of the spectral distributions in the macroscopic limit and the quenched approximation, follow algebraically from the discontinuity of a pertinent solution to a cubic (Cardano) or a quartic (Ferrari) equation. We use the end-point equation of the energy spectra in chiral random matrix models to argue for novel phase structures, in which the Dirac density of states plays the role of an order parameter. (orig.)

  4. Decreased scattering coefficient of blue sclerae

    NARCIS (Netherlands)

    Lanting, P J; Borsboom, P C; te Meerman, G J; ten Kate, L P

    1985-01-01

    The optical scattering properties of blue and normal sclerae were studied with a fiber optic scattering monitor. The scattering was clearly reduced in two osteogenesis imperfecta patients with blue sclerae, and low normal in one osteogenesis imperfecta patient without blue sclerae.

  5. Status of Blue Ridge Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    1990-09-01

    This is one in a series of reports prepared by the Tennessee Valley Authority (TVA) for those interested in the conditions of TVA reservoirs. This overview of Blue Ridge Reservoir summarizes reservoir and watershed characteristics, reservoir uses and use impairments, water quality and aquatic biological conditions, and activities of reservoir management agencies. This information was extracted from the most current reports and data available, as well as interview with water resource professionals in various federal, state, and local agencies. Blue Ridge Reservoir is a single-purpose hydropower generating project. When consistent with this primary objective, the reservoir is also operated to benefit secondary objectives including water quality, recreation, fish and aquatic habitat, development of shoreline, aesthetic quality, and other public and private uses that support overall regional economic growth and development. 8 refs., 1 fig.

  6. Thermoluminescence (TL) of Egyptian Blue

    Energy Technology Data Exchange (ETDEWEB)

    Schvoerer, M.; Delavergne, M.-C.; Chapoulie, R.

    1988-01-01

    Egyptian Blue is a synthesized crystalline pictorial pigment with formula CaCuSi/sub 4/O/sub 10/. It has been used in Egypt and Mesopotamia from the 3rd millenium B.C. A preliminary experiment on a recently synthesized sample showed that this pigment is thermoluminescent after ..beta.. irradiation (/sup 90/Sr). As the signal intensity grows linearly with the administered dose within the temperature range commonly used in TL dating, we have been looking for this phenomenon from archaeological pigments. It was encountered with two samples found in excavation. From its intensity and stability we concluded that Egyptian Blue can be dated using TL. This first and positive result encouraged us to extend the method to other types of mineral pigments synthesized by early man, and to suggest that it may be used for direct dating of ancient murals.

  7. The Physics of the Blues

    Science.gov (United States)

    Gibson, J. Murray

    2009-03-01

    In looking at the commonalities between music and science, one sees that the musician's palette is based on the principles of physics. The pitch of a musical note is determined by the frequency of the sound wave. The scales that musicians use to create and play music can be viewed as a set of rules. What makes music interesting is how musicians develop those rules and create ambiguity with them. I will discuss the evolution of western musical scales in this context. As a particular example, ``Blue'' notes are very harmonic notes that are missing from the equal temperament scale. The techniques of piano blues and jazz represent the melding of African and Western music into something totally new and exciting. Live keyboard demonstrations will be used. Beyond any redeeming entertainment value the talk will emphasize the serious connections between science and art in music. Nevertheless tips will be accepted.

  8. Project Tasks in Robotics

    DEFF Research Database (Denmark)

    Sørensen, Torben; Hansen, Poul Erik

    1998-01-01

    Description of the compulsary project tasks to be carried out as a part of DTU course 72238 Robotics......Description of the compulsary project tasks to be carried out as a part of DTU course 72238 Robotics...

  9. FAILURE OF Zr50Ti16.5Cu15Ni18.5 AMORPHOUS METALLIC RIBBON

    NARCIS (Netherlands)

    Miskuf, J.; Csach, K.; Jurikova, A.; Ocelik, V.; Bengus, V.; Tabachnikova, E.

    2008-01-01

    The deformation and fracture behavior of Zr50Ti16.5Cu15Ni18.5 bulk amorphous metal in the form of a thin ribbon have been determined in tensile test at room temperature. The fracture is localized in a major shear band and the fracture angle between the tensile stress axis and the fracture plane is c

  10. 75 FR 7236 - Narrow Woven Ribbons with Woven Selvedge from Taiwan: Preliminary Determination of Sales at Less...

    Science.gov (United States)

    2010-02-18

    ... Determination of Sales at Less Than Fair Value and Postponement of Final Determination AGENCY: Import... United States at less than fair value (LTFV), as provided in section 733(b) of the Tariff Act of 1930, as... and pre-cut, hand-finished narrow woven ribbons for retail packaging in lengths of 72 inches or...

  11. Development of Ribbon Fiber Type Multi-Channel Power Level Monitor with Low-Insertion/Polarization Loss

    Institute of Scientific and Technical Information of China (English)

    Maki; Inai; Akira; Haraguchi; Takeo; Komiya; Kiyotaka; Murashima; Takashi; Sasaki; Kazuhito; Saitoh

    2003-01-01

    We would like to propose a new in-line multi-channel power level monitor, which is applicable as tap-monitor for multi-channel WDM signals. Its ribbon fiber structure has far exceeded PLC performance and realized compact-size and lower insertion/polarization dependent loss.

  12. Magneto-caloric effect of FexZryB100-x-y metallic ribbons for room temperature magnetic refrigeration

    Science.gov (United States)

    Guo, D. Q.; Chan, K. C.; Xia, L.; Yu, P.

    2017-02-01

    Among various amorphous magnetic materials, even though Fe-based materials do not have high magnetocaloric effect (MCE), their advantages of tunable Curie temperature (TC) and low cost have attracted considerable attention in regard to room temperature magnetic refrigeration applications. With the aim of enhancing the MCE, the influence of boron addition on Fe-based amorphous materials was investigated in this study. Fe94-xZr6Bx (x=5, 6, 8 and 10), Fe91-yZr9By (y=3, 4, 5, 6, 8 and 10) and Fe89-zZr11Bz (z=3, 4, 5, 6, 8 and 10) specimens were made in ribbon form and their magnetocaloric effect was investigated. The Curie temperature (TC) of all three series of ribbons underwent an almost linear increase, and the peak magnetic entropy change, | Δ SMpeak | (obtained in a magnetic field of 1.5 T), generally increases with increasing boron content. The results further show that the Fe86Zr9B5 ribbon exhibits a relatively large | Δ SMpeak | value of 1.13 J/kgK at 330 K and a large refrigerant capacity value of 135.6 J/kg under 1.5 T. On the basis of these results, although there is still much scope for improvement before totally replacing the conventional cooling method, the Fe-based amorphous ribbon can be seen as a promising magnetocaloric material for room temperature magnetic refrigeration applications.

  13. Evolution of Flare Ribbons, Electric Currents and Quasi-separatrix Layers During an X-class Flare

    CERN Document Server

    Janvier, M; Pariat, E; Tassev, S; Millholland, S; Bommier, V; McCauley, P; McKillop, S; Dougan, F

    2016-01-01

    The standard model for eruptive flares has in the past few years been extended to 3D. It predicts typical J-shaped photospheric footprints of the coronal current layer, forming at similar locations as the Quasi-Separatrix Layers (QSLs). Such a morphology is also found for flare ribbons observed in the EUV band, as well as in non-linear force-free field (NLFFF) magnetic field extrapolations and models. We study the evolution of the photospheric traces of the current density and flare ribbons, both obtained with the SDO instruments. We investigate the photospheric current evolution during the 6 September 2011 X-class flare (SOL2011-09-06T22:20) from observational data of the magnetic field obtained with HMI. This evolution is compared with that of the flare ribbons observed in the EUV filters of the AIA. We also compare the observed electric current density and the flare ribbon morphology with that of the QSLs computed from the flux rope insertion method/NLFFF model. The NLFFF model shows the presence of a fan-...

  14. 78 FR 41371 - Endangered and Threatened Wildlife; Determination on Whether To List the Ribbon Seal as a...

    Science.gov (United States)

    2013-07-10

    ...) described a zone of sea ice that remains in the central Bering Sea until melting around mid-June. Satellite... Annual Formation of the Ribbon Seal's Sea Ice Habitat Unlike the Arctic Ocean, where some sea ice is... cold and darkness that occurs in winter. Despite the recent dramatic reductions in Arctic Ocean...

  15. Launching Complex Tasks

    Science.gov (United States)

    Jackson, Kara J.; Shahan, Emily C.; Gibbons, Lynsey K.; Cobb, Paul A.

    2012-01-01

    Mathematics lessons can take a variety of formats. In this article, the authors discuss lessons organized around complex mathematical tasks. These lessons usually unfold in three phases. First, the task is introduced to students. Second, students work on solving the task. Third, the teacher "orchestrates" a concluding whole-class discussion in…

  16. Task assignment and coaching

    NARCIS (Netherlands)

    Dominguez-Martinez, S.

    2009-01-01

    An important task of a manager is to motivate her subordinates. One way in which a manager can give incentives to junior employees is through the assignment of tasks. How a manager allocates tasks in an organization, provides information to the junior employees about his ability. Without coaching fr

  17. Effect of the substitution of Gd for Sm on magnetic anisotropy of melt-spun Sm1-xGdxCo5 ribbons

    Science.gov (United States)

    Zhang, Wen-Yong; Yan, A.-Ru; Zhang, Hong-Wei; Zhang, Shao-Ying; Shen, Bao-, Gen

    2001-04-01

    Magnetically anisotropic Sm1-xGdxCo5 (0≤x≤0.5) ribbons have been prepared by single-roller melt spinning at a low wheel speed of 5 m s-1. X-ray diffraction results show that the substitution of Gd for Sm enhances the relative intensity of the diffraction peak of index (200) and favours the formation of a strong (002) texture parallel to the longitudinal direction of the ribbons. This results in the increase of the remanence ratio with the increase of x. By scanning electron microscopy measurements, it is found that the Gd-containing ribbons have a more regular grain arrangement and a more homogeneous distribution of grain size compared to the Gd-free ribbons. The rectangularity of demagnetization curves is obviously improved with the increase of x. A maximum remanence ratio (0.93) and best rectangularity of the demagnetization curves have been obtained for ribbons with x = 0.5. However, the replacement of Sm by Gd also leads to the linear decrease of the remanence of SmCo5 ribbons. The optimum magnetic properties, Mr = 0.84 T, iHc = 10.4 kOe, (BH)max = 16.7 MGOe, have been achieved in the as-annealed ribbons with x = 0.2.

  18. Early diagenetic deformation structures of the Furongian ribbon rocks in Shandong Province of China——A new perspective of the genesis of limestone conglomerates

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Ribbon rocks are characterized by an alternation of millimeter-to centimeter-thick limestone and argillaceous deposits (marlstone or shale).The sedimentary processes and diagenetic characteristics of ribbon rocks might be critical to the formation of limestone conglomerates.According to detailed field measurement and laboratory analyses (thin section observation and XRD analysis),four types of ribbon rocks are classified,i.e.,limestone and marlstone couplet (L-M),limestone and shale couplet (L-S),thin-bedded lime mudstone (Ltb),and laminated limestone and marlstone couplet (Cl).These ribbon rocks were mostly deposited in low-energy subtidal environments (below fair-weather wave base).Ribbon rocks exhibit various subtle deformation structures such as intrastratal cracks and "boudin" structures.Differential cementation of carbonate and argillaceous layers during early diagenesis is a prerequisite condition for the deformation of ribbon rock under compaction.Ribbon rocks would be deformed into limestone conglomerates under differential compaction that might be triggered by external forces such as storm and earthquake.

  19. Effect of annealing on the magnetic, magnetocaloric and magnetoresistance properties of Ni-Co-Mn-Sb melt spun ribbons 

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, Roshnee [Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India); Raj Kumar, D.M.; Arvindha Babu, D. [Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); Suresh, K.G., E-mail: suresh@phy.iitb.ac.in [Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India); Nigam, A.K. [Tata Institute of Fundamental Research, Mumbai 400005 (India); Manivel Raja, M. [Defence Metallurgical Research Laboratory, Hyderabad 500058 (India)

    2013-12-15

    The structural, magnetic, magnetocaloric and magnetotransport properties of Ni{sub 46}Co{sub 4}Mn{sub 38}Sb{sub 12} melt spun ribbons have been systematically investigated. The partially ordered B2 phase of the as-spun ribbon transforms to fully ordered L2{sub 1} phase upon annealing, which signifies a considerable change of the atomic ordering in the system. The presence of atomic disorder in the as-spun ribbon gives rise to a higher martensitic transition temperature and a lower magnetization as compared to the bulk sample. However, annealing the ribbons helps in regaining the bulk properties to a large extent. Significant changes in magnetocaloric effect, exchange bias and magnetoresistance have been observed between the as-spun and the annealed ribbons, indicating the role of atomic ordering on the functional as well as fundamental properties in the Heusler system. Importantly, the study shows that one can reduce the hysteresis loss by preparing melt spun alloys and subjecting them to appropriate annealing conditions, which enable them to become practical magnetic refrigerants. - Highlights: • In this paper we have systematically studied various phenomenon caused by the heat treatment of the melt spun NiCoMnSb samples. • Significant changes in magnetocaloric effect, exchange bias and magnetoresistance have been observed between the as-spun and the annealed ribbons. • Another important result is annealing the ribbons helps in regaining the bulk properties to a large extent.

  20. Role of aluminium addition on structure of Fe substituted Fe73.5−Si13.5B9Nb3Cu1Al alloy ribbons

    Indian Academy of Sciences (India)

    Gautam Agarwal; Himanshu Agrawal; M Srinivas; B Majumdar; N K Mukhopadhyay

    2013-08-01

    The investigation has dealt with the structure and magnetic properties of rapidly solidified and annealed Fe73.5−Si13.5B9Nb3Cu1Al ( = 0, 2, 4, 6 at%) ribbons prepared by melt spinning. Complete amorphous structure was obtained in as-spun ribbons of = 0 and 2 at% compositions, whereas structure of ribbons containing higher Al was found to be partially crystalline. Detailed thermal analyses of the alloys and the melt spun ribbons revealed that the glass forming ability in the form of x/l (ratio between crystallization and liquidus temperature) is the highest for 2 at% Al alloys and decreases with further addition of Al. Annealing of all as spun ribbons resulted in the precipitation of nanocrystalline phase embedded in amorphous matrix in the form of either 3 phase or -Fe(Si/Al) solid solution depending on the initial composition of the alloy. Only -Fe(Si/Al) solid solution was formed in 2 at% Al ribbons whereas ordered DO3 structure was found to be stabilized in other ribbons including 0 at% Al. A detailed study on determination of precision lattice parameter of nanocrystalline phase revealed that the lattice parameter increases with the addition of Al indicating the partitioning behaviour of Al in nanocrystalline phase.

  1. Microstructure, biocorrosion and cytotoxicity evaluations of rapid solidified Mg-3Ca alloy ribbons as a biodegradable material

    Energy Technology Data Exchange (ETDEWEB)

    Gu, X N; Zhou, W R; Zheng, Y F [State Key Laboratory for Turbulence and Complex System and Department of Advanced Materials and Nanotechnology, College of Engineering, Peking University, Beijing 100871 (China); Li, X L [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Cheng, Y, E-mail: yfzheng@pku.edu.c [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China)

    2010-06-01

    Rapidly solidified (RS) Mg-3Ca alloy ribbons were prepared by the melt-spinning technique at different wheel rotating speeds (15 m s{sup -1}, 30 m s{sup -1} and 45 m s{sup -1}) with the as-cast Mg-3Ca alloy ingot as a raw material. The RS45 Mg-3Ca alloy ribbon showed a much more fine grain size feature (approximately 200-500 nm) in comparison to the coarse grain size (50-100 {mu}m) of the original as-cast Mg-3Ca alloy ingot. The corrosion electrochemical tests in simulated body fluid indicated that the corrosion rate of the as-cast Mg-3Ca alloy was strongly reduced by the RS procedure and tended to be further decreased with increasing wheel rotating speeds (1.43 mm yr{sup -1} for RS15, 0.94 mm yr{sup -1} for RS30 and 0.36 mm yr{sup -1} for RS45). The RS Mg-3Ca alloy ribbons showed more uniform corrosion morphology compared with the as-cast Mg-3Ca alloy after polarization. The cytotoxicity evaluation revealed that the three experimental as-spun Mg-3Ca alloy ribbon extracts did not induce toxicity to the L-929 cells, whereas the as-cast Mg-3Ca alloy ingot extract did. The L-929 cells showed more improved adhesion on the surfaces of the three as-spun Mg-3Ca alloy ribbons than that of the as-cast Mg-3Ca alloy ingot.

  2. Microstructure, biocorrosion and cytotoxicity evaluations of rapid solidified Mg-3Ca alloy ribbons as a biodegradable material.

    Science.gov (United States)

    Gu, X N; Li, X L; Zhou, W R; Cheng, Y; Zheng, Y F

    2010-06-01

    Rapidly solidified (RS) Mg–3Ca alloy ribbons were prepared by the melt-spinning technique at different wheel rotating speeds (15 m s(-1), 30 m s(-1) and 45 m s(-1) with the as-cast Mg–3Ca alloy ingot as a raw material. The RS45 Mg–3Ca alloy ribbon showed a much more fine grain size feature (approximately 200–500 nm) in comparison to the coarse grain size (50–100 μm)of the original as-cast Mg–3Ca alloy ingot. The corrosion electrochemical tests in simulated body fluid indicated that the corrosion rate of the as-cast Mg–3Ca alloy was strongly reduced by the RS procedure and tended to be further decreased with increasing wheel rotating speeds(1.43 mm yr(-1) for RS15, 0.94 mm yr(-1) for RS30 and 0.36 mm yr(-1) for RS45). The RS Mg–3Ca alloy ribbons showed more uniform corrosion morphology compared with the as-cast Mg–3Ca alloy after polarization. The cytotoxicity evaluation revealed that the three experimental as-spun Mg–3Ca alloy ribbon extracts did not induce toxicity to the L-929 cells,whereas the as-cast Mg–3Ca alloy ingot extract did. The L-929 cells showed more improved adhesion on the surfaces of the three as-spun Mg–3Ca alloy ribbons than that of the as-cast Mg–3Ca alloy ingot.

  3. Adsorption of Methylene Blue, Bromophenol Blue, and Coomassie Brilliant Blue by α-chitin nanoparticles

    Directory of Open Access Journals (Sweden)

    Solairaj Dhananasekaran

    2016-01-01

    Full Text Available Expelling of dyestuff into water resource system causes major thread to the environment. Adsorption is the cost effective and potential method to remove the dyes from the effluents. Therefore, an attempt was made to study the adsorption of dyestuff (Methylene Blue (MB, Bromophenol Blue (BPB and Coomassie Brilliant Blue (CBB by α-chitin nanoparticles (CNP prepared from Penaeus monodon (Fabricius, 1798 shell waste. On contrary to the most recognizable adsorption studies using chitin, this is the first study using unique nanoparticles of ⩽50 nm used for the dye adsorption process. The results showed that the adsorption process increased with increase in the concentration of CNP, contact time and temperature with the dyestuff, whereas the adsorption process decreased with increase in the initial dye concentration and strong acidic pH. The results from Fourier transform infrared (FTIR spectroscopy confirmed that the interaction between dyestuff and CNP involved physical adsorption. The adsorption process obeys Langmuir isotherm (R2 values were 0.992, 0.999 and 0.992 for MB, BPB and CBB, and RL value lies between 0 and 1 for all the three dyes and pseudo second order kinetics (R2 values were 0.996, 0.999 and 0.996 for MB, BPB and CBB more effectively. The isotherm and kinetic models confirmed that CNP can be used as a suitable adsorbent material for the removal of dyestuff from effluents.

  4. Standard test method for abrasiveness of ink-impregnated fabric printer ribbons and other web materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the determination of the abrasiveness of ink-impregnated fabric printer ribbons and other web materials by means of a sliding wear test. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  5. Magnetic properties and atomic ordering of BCC Heusler alloy Fe2MnGa ribbons

    Science.gov (United States)

    Xin, Yuepeng; Ma, Yuexing; Luo, Hongzhi; Meng, Fanbin; Liu, Heyan

    2016-05-01

    The electronic structure, atomic disorder and magnetic properties of the Heusler alloy Fe2MnGa have been investigated experimentally and theoretically. BCC Fe2MnGa ribbon samples were prepared. Experimentally, a saturation magnetic moment (3.68 μB at 5 K) much larger than the theoretical value (2.04 μB) has been reported. First-principles calculations indicate that the difference is related to the Fe-Mn disorder between A, B sites, as can also be deduced from the XRD pattern. L21 type Fe2MnGa is a ferrimagnet with antiparallel Fe and Mn spin moments. However, when Fe-Mn disorder occurs, part of Mn moments will be parallel to Fe moments, and the Fe moments also clearly increase simultaneously. All this results in a total moment of 3.74 μB, close to the experimental value.

  6. Polyethylene ribbon and fixed orthodontic retention and porcelain veneers: solving an esthetic dilemma.

    Science.gov (United States)

    Iniguez, I; Strassler, H E

    1998-01-01

    The patient, a 58-year-old woman, had started orthodontic treatment to correct spacing between the maxillary anterior teeth 6 year prior to presentation with a chief complaint of tooth discoloration and spacing. The treatment had consisted of the use of a removable appliance to retract the maxillary anterior teeth. The patient continued to wear the appliance sporadically. When she presented, the maxillary incisors were in primary occlusal trauma with Grade 2 mobility. The patient discontinued wearing the appliance. The periodontal condition was addressed with initial therapy. As part of the treatment plan to stabilize the maxillary anterior teeth and provide the patient with an esthetic result, it was decided to do a limited occlusal adjustment of the maxillary anterior teeth to control fremitus, and to place a fixed, composite resin, polyethylene ribbon-reinforced splint, using a facial approach. The esthetic restoration of these teeth was accomplished with bonded porcelain veneers.

  7. Effect of Laser Annealing on Permeability Spectra in Co-based Amorphous Ribbon

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    We investigated the variation of permeability spectra and relaxation frequency in Co-based amor phous ribbon annealed by pulsed Nd:YAG laser at various annealing energy Ea. The complex permeability spectra varies sensitively with the annealing energy, where the spectra could be decomposed into two contributions from domain wall motion,μdw(f)and rotational magnetiza tion μrot(f) by analyzing the rneasured spectra as a function of driving ac field amplitude. The magnitude ofμdw(f) andμrot(f) in dc limit shows maximum at Ea = 176 mJ. The maximum relaxation frequency for rotational magnetization, determined byu″(f) curve, is about 700 kHz at Ea=62 mJ but that for wall motion is about 26 kHz at 230 mJ. These variations reflect the increase of magnetic softness and microstructural change by the annealing.

  8. Small-scale explosive seam welding. [using ribbon explosive encased in lead sheath

    Science.gov (United States)

    Bement, L. J.

    1972-01-01

    A unique small scale explosive seam welding technique is reported that has successfully joined a variety of aluminum alloys and alloy combinations in thicknesses to 0.125 inch, as well as titanium in thicknesses to 0.056 inch. The explosively welded joints are less than one-half inch in width and apparently have no long length limitation. The ribbon explosive developed in this study contains very small quantities of explosive encased in a flexible thin lead sheath. The evaluation and demonstration of this welding technique was accomplished in three phases: evaluation and optimization of ten major explosive welding variables, the development of four weld joints, and an applicational analysis which included photomicrographs, pressure integrity tests, vacuum effects, and fabrication of some potentially useful structures in aluminum and titanium.

  9. Magnetic Moment and Band Structure Analysis of Fe, Co, Ni-modified Graphene-nano- ribbon

    OpenAIRE

    Ota, Norio

    2014-01-01

    Magnetic properties and band characteristics of graphene-nano-ribbon (GNR) modified by Fe, Co, and Ni were analyzed by the first principles DFT calculation. Typical unit cell is [C32H2Fe1], [C32H2Co1] and [C32H2Ni1] respectively. The most stable spin state was Sz=4/2 for Fe-modified GNR, whereas Sz=3/2 for Co-case and Sz=2/2 for Ni-case. Atomic magnetic moment of Fe, Co and Ni were 3.63, 2.49 and 1.26 {\\mu}B, which were reduced values than that of atomic Hund-rule due to magnetic coupling wit...

  10. A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers.

    Science.gov (United States)

    Zhang, Fucheng; Zhou, Zhonghe; Xu, Xing; Wang, Xiaolin; Sullivan, Corwin

    2008-10-23

    Recent coelurosaurian discoveries have greatly enriched our knowledge of the transition from dinosaurs to birds, but all reported taxa close to this transition are from relatively well known coelurosaurian groups. Here we report a new basal avialan, Epidexipteryx hui gen. et sp. nov., from the Middle to Late Jurassic of Inner Mongolia, China. This new species is characterized by an unexpected combination of characters seen in several different theropod groups, particularly the Oviraptorosauria. Phylogenetic analysis shows it to be the sister taxon to Epidendrosaurus, forming a new clade at the base of Avialae. Epidexipteryx also possesses two pairs of elongate ribbon-like tail feathers, and its limbs lack contour feathers for flight. This finding shows that a member of the avialan lineage experimented with integumentary ornamentation as early as the Middle to Late Jurassic, and provides further evidence relating to this aspect of the transition from non-avian theropods to birds.

  11. Graphene plasmons embedded in a gain medium: layer and ribbon plasmons

    Science.gov (United States)

    Altares Menendez, Galaad; Rosolen, Gilles; Maes, Bjorn

    2016-12-01

    Graphene plasmonics has attracted much attention due to its remarkable properties such as tunable conductivity and extreme confinement. However, losses remain one of the major drawbacks to developing more efficient devices based on graphene plasmons. Here we show that when a gain medium is introduced around a 1D graphene sheet, lossless propagation can be achieved for a critical gain value. Both numerics and analytics are employed; and with the Drude approximation the analytical expression for this critical gain becomes remarkably simple. Furthermore, we examine a single 2D graphene nanoribbon within a gain environment. We report that the plasmonic resonant modes exhibit a spasing effect for a specific value of the surrounding gain. This feature is indicated by an absorption cross section that strongly increases and narrows. Finally, we manage to connect the ribbon results to the 1D sheet critical gain, by taking external coupling into account.

  12. Synthesis, Crystal Structure and Magnetic Property of the Polymeric Ribbon: [Co(ip)(phen)]n

    Institute of Scientific and Technical Information of China (English)

    ZHOU You-Fu; SHI Qian; YUAN Da-Qiang; XU Yan-Qing; HONG Mao-Chun

    2005-01-01

    A metal-organic coordination polymer [Co(ip)(phen)]n (ip = isophthalate, phen = 1,10-phenanthroline) 1 has been hydrothermally synthesized and characterized.Compound 1 crystallizes in P2/c space group with a = 8.37(2), b = 10.41(1), c = 18.36(3) (A), β = 100.41(7)o, C20H12CoN2O4, Mr = 403.25, V = 1573(4) (A)3, Z = 4 and Dc = 1.703 g/cm3.Two Co(II) ions are bridged by μ-carboxylate to form a dinuclear unit, which is extended by ip ligands resulting in a ribbon-like chain.Pairs of phen ligands attach to the dinuclear units on both sides of the chain alternately.Magnetic study reveals that the interaction between the carboxylate-bridged Co(II) ions in 1 is weakly antiferromagnetic.

  13. Reverse rectification and negative differential resistance effects in doped armchair graphene ribbons device

    Science.gov (United States)

    Yuan, Peipei; Zheng, Yapeng; Bian, Baoan; Liao, Bin

    2016-09-01

    In the present work, we perform first-principles calculations based on density functional theory and non-equilibrium Green's function to study the electronic transport properties of the 10-armchair graphene ribbons devices doped by boron and phosphorus atoms. Two kinds of device show a strong inverse rectification and negative differential resistance (NDR) effect. The effect of doping position on rectifying phenomenon are analyzed by calculating the transmission spectra and the energy band structures of the related electrodes as well as the projected density of states for two devices at different bias. And the observed NDR effect is explained by the local density of states. The results indicate that the asymmetric doping of the impurity atom contributes to the electron transport of the device, being used to design a molecular rectifier with good performance.

  14. LOCAL INTERSTELLAR MAGNETIC FIELD DETERMINED FROM THE INTERSTELLAR BOUNDARY EXPLORER RIBBON

    Energy Technology Data Exchange (ETDEWEB)

    Zirnstein, E. J.; Livadiotis, G.; McComas, D. J. [Southwest Research Institute, San Antonio, TX 78228 (United States); Heerikhuisen, J.; Pogorelov, N. V. [Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Funsten, H. O., E-mail: ezirnstein@swri.edu [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2016-02-10

    The solar wind emanating from the Sun interacts with the local interstellar medium (LISM), forming the heliosphere. Hydrogen energetic neutral atoms (ENAs) produced by the solar-interstellar interaction carry important information about plasma properties from the boundaries of the heliosphere, and are currently being measured by NASA's Interstellar Boundary Explorer (IBEX). IBEX observations show the existence of a “ribbon” of intense ENA emission projecting a circle on the celestial sphere that is centered near the local interstellar magnetic field (ISMF) vector. Here we show that the source of the IBEX ribbon as a function of ENA energy outside the heliosphere, uniquely coupled to the draping of the ISMF around the heliopause, can be used to precisely determine the magnitude (2.93 ± 0.08 μG) and direction (227.°28 ± 0.°69, 34.°62 ± 0.°45 in ecliptic longitude and latitude) of the pristine ISMF far (∼1000 AU) from the Sun. We find that the ISMF vector is offset from the ribbon center by ∼8.°3 toward the direction of motion of the heliosphere through the LISM, and their vectors form a plane that is consistent with the direction of deflected interstellar neutral hydrogen, thought to be controlled by the ISMF. Our results yield draped ISMF properties close to that observed by Voyager 1, the only spacecraft to directly measure the ISMF close to the heliosphere, and give predictions of the pristine ISMF that Voyager 1 has yet to sample.

  15. Why Are Flare Ribbons Associated with the Spines of Magnetic Null Points Generically Elongated?

    Science.gov (United States)

    Pontin, David; Galsgaard, Klaus; Démoulin, Pascal

    2016-08-01

    Coronal magnetic null points exist in abundance, as demonstrated by extrapolations of the coronal field, and have been inferred to be important for a broad range of energetic events. These null points and their associated separatrix and spine field lines represent discontinuities of the field line mapping, making them preferential locations for reconnection. This field line mapping also exhibits strong gradients adjacent to the separatrix (fan) and spine field lines, which can be analysed using the "squashing factor", Q. In this article we analyse in detail the distribution of Q in the presence of magnetic nulls. While Q is formally infinite on both the spine and fan of the null, the decay of Q away from these structures is shown in general to depend strongly on the null-point structure. For the generic case of a non-radially-symmetric null, Q decays most slowly away from the spine or fan in the direction in which |{B}| increases most slowly. In particular, this demonstrates that the extended elliptical high-Q halo around the spine footpoints observed by Masson et al. ( Astrophys. J. 700, 559, 2009) is a generic feature. This extension of the Q halos around the spine or fan footpoints is important for diagnosing the regions of the photosphere that are magnetically connected to any current layer that forms at the null. In light of this, we discuss how our results can be used to interpret the geometry of observed flare ribbons in circular ribbon flares, in which typically a coronal null is implicated. We conclude that both the physics in the vicinity of the null and how this is related to the extension of Q away from the spine or fan can be used in tandem to understand observational signatures of reconnection at coronal null points.

  16. DC bias immune nanocrystalline magnetic cores made of Fe73Nb3Cu1B7Si16 ribbon with induced transverse magnetic anisotropy

    Science.gov (United States)

    Nosenko, Anton; Rudenko, Olexandr; Mika, Taras; Yevlash, Igor; Semyrga, Olexandr; Nosenko, Viktor

    2016-02-01

    The comparative analysis of magnetic properties of cut cores made of nanocrystalline Fe73Nb3Cu1B7Si16 alloy ribbon and cores made of the same ribbon with preliminary tension-induced transverse magnetic anisotropy was carried out. The possibility of improving magnetic properties of cut cores, decreasing loss, and increasing DC bias immunity of reversible magnetic permeability is presented. The influence of induced magnetic anisotropy on DC bias immunity of reversible magnetic permeability was investigated. The advantages and disadvantages of new cores (made of ribbon heated under tensile stress) over cut ones were determined.

  17. DC bias immune nanocrystalline magnetic cores made of Fe73Nb3Cu1B7Si16 ribbon with induced transverse magnetic anisotropy.

    Science.gov (United States)

    Nosenko, Anton; Rudenko, Olexandr; Mika, Taras; Yevlash, Igor; Semyrga, Olexandr; Nosenko, Viktor

    2016-12-01

    The comparative analysis of magnetic properties of cut cores made of nanocrystalline Fe73Nb3Cu1B7Si16 alloy ribbon and cores made of the same ribbon with preliminary tension-induced transverse magnetic anisotropy was carried out. The possibility of improving magnetic properties of cut cores, decreasing loss, and increasing DC bias immunity of reversible magnetic permeability is presented. The influence of induced magnetic anisotropy on DC bias immunity of reversible magnetic permeability was investigated. The advantages and disadvantages of new cores (made of ribbon heated under tensile stress) over cut ones were determined.

  18. Fire Whirls, Vortex Breakdown(?), and Blue Whirls

    Science.gov (United States)

    Oran, Elaine; Xiao, Huahua; Gollner, Michael

    2016-11-01

    As we were investigating the efficiency of fire-whirl burning on water, we observed the usual transformation of a pool fire to a fire whirl, and then suddenly, we saw the fire undergo a third transition. A blue cup appeared around the base of the fire whirl, surrounding the yellow flame, the yellow flame receded into the cup and finally disappeared. What remained was a small, rapidly spinning blue flame that burned until the fuel on the water was consumed. The blue whirl was shaped like a spinning cup, closed at the bottom near the water surface, and spreading in radius moving upwards towards the rim. Above the blue cup lip, there was a purple cone-shaped mist. The fuel was usually n-heptane, but at one point it was crude oil, and still the blue whirl formed naturally. The height of the fire whirl on the laboratory pan was larger than a half meter, and this evolved into a blue whirl about 4-8 cm high. Occasionally the blue whirl would become "unstable" and revert to a transitional state of blue cup holding a yellow flame. When the blue whirl formed, turbulence seemed to disappear, and the flame became quiet. We will show videos of how this happened and discuss the evolution of the fire whirl to the blue whirl in vortex-breakdown concepts. This work was supported by and EAGER award from NSF and Minta Martin Endowment Funds in the Department of Aerospace Engineering at the University of Maryland.

  19. Deep Blue Cannot Play Checkers: The Need for Generalized Intelligence for Mobile Robots

    Directory of Open Access Journals (Sweden)

    Troy D. Kelley

    2010-01-01

    Full Text Available Generalized intelligence is much more difficult than originally anticipated when Artificial Intelligence (AI was first introduced in the early 1960s. Deep Blue, the chess playing supercomputer, was developed to defeat the top rated human chess player and successfully did so by defeating Gary Kasporov in 1997. However, Deep Blue only played chess; it did not play checkers, or any other games. Other examples of AI programs which learned and played games were successful at specific tasks, but generalizing the learned behavior to other domains was not attempted. So the question remains: Why is generalized intelligence so difficult? If complex tasks require a significant amount of development, time and task generalization is not easily accomplished, then a significant amount of effort is going to be required to develop an intelligent system. This approach will require a system of systems approach that uses many AI techniques: neural networks, fuzzy logic, and cognitive architectures.

  20. Various Shades of Blue's Functions

    CERN Document Server

    Janik, R A; Papp, G; Zahed, I; Janik, Romuald A.; Nowak, Maciej A.; Papp, Gabor; Zahed, Ismail

    1997-01-01

    We discuss random matrix models in terms of elementary operations on Blue's functions (functional inverse of Green's functions). We show that such operations embody the essence of a number of physical phenomena whether at/or away from the critical points. We illustrate these assertions by borrowing on a number of recent results in effective QCD in vacuum and matter. We provide simple physical arguments in favor of the universality of the continuum QCD spectral oscillations, whether at zero virtuality, in the bulk of the spectrum or at the chiral critical points. We also discuss effective quantum systems of disorder with strong or weak dissipation (Hatano-Nelson localization).

  1. Blue-Green Colour Categorisation in Mandarin-English Speakers

    Directory of Open Access Journals (Sweden)

    Emily Joanne Hird

    2012-05-01

    Full Text Available Observers are faster to detect a target among a set of distracters if the targets and distracters come from different colour categories. This cross-boundary advantage seems to be limited to the right visual field, which is consistent with the dominance of the left hemisphere for language processing. Here we study whether a similiar visual field advantage is found in Mandarin, a language which uses a logographic system. Forty late Mandarin-English bilinguals performed a blue-green colour categorisation task, in a blocked design, in their first language (L1: Mandarin or second language (L2: English. Eleven colour singletons ranging from blue to green were presented for 160ms, randomly in the left visual field (LVF or in the right visual field (RVF. We find that reaction times at the colour boundary were on average about 100 ms shorter in the LVF compared to the RVF, but only when the task was preformed in Mandarin as opposed to English. The apparent discrepancy with previous findings is conceivably due to the script nature of two languages: Mandarin logographic characters are analysed visuo-orthographically in the right fusiform gyrus [Guo and Burgund 2010, Brain Lang 115].

  2. From Desktop to Teraflop: Exploiting the U.S. Lead in High Performance Computing. NSF Blue Ribbon Panel on High Performance Computing.

    Science.gov (United States)

    National Science Foundation, Washington, DC.

    This report addresses an opportunity to accelerate progress in virtually every branch of science and engineering concurrently, while also boosting the American economy as business firms also learn to exploit these new capabilities. The successful rapid advancement in both science and technology creates its own challenges, four of which are…

  3. FLOAT Project - Task 1

    DEFF Research Database (Denmark)

    Marchalot, Tanguy; Kofoed, Jens Peter; Sørensen, Eigil V.

    The objective of the FLOAT project is to study the reliability of high-performance fibre-reinforced concrete, also known as Compact Reinforced Composite (CRC), for the floats of wave energy converters. In order to reach commercial breakthrough, wave energy converters need to achieve a lower price.......com, 2011). CRC floats could be a very cost-effective technology with enhanced loading capacity and environmental resistance, and very low maintenance requirements, affecting directly the final energy price. The project involves DEXA Wave Energy Ltd, Wave Star A/S, Aalborg University and Hi-Con A....../S. It is divided in 4 tasks: Task 1: Preliminary float design and economic considerations Task 2: Material characteristics Task 3: Preliminary experiences Task 4: The importance for wave energy The present report covers Task 1....

  4. A Brief Analysis of Communication Tasks in Task- based Teaehing

    Institute of Scientific and Technical Information of China (English)

    Xu Xiaoying

    2011-01-01

    Task -Based Language Teaching (TBLT) aims at proving opportunities for the learners to experiment with and explore both spoken and written language through learning activities. This passage further exam if the following four communicative tasks jigsaw tasks, role - play tasks, problem solving tasks, and information gap tasks can assist classroom learning.

  5. Study of the magnetic anisotropy induced in CoFeSiB amorphous ribbons by solidification in a magnetic field using giant magnetoimpedance measurements

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, J.A. [Departmento de Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007, Oviedo (Spain); Saad, A. [Departmento de Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007, Oviedo (Spain) and Laboratorio de Solidos Amorfos, Departmento de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo de Colon 850, C10063ACV Capital Federal (Argentina)]. E-mail: asaad@fi.uba.ar; Garcia-Arribas, A. [Departemento de Electricidad y Electronica, Universidad del Pais Vasco, Apartado 644, 48080 Bilbao (Spain); Santos, J.D. [Departmento de Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007, Oviedo (Spain); Elbaile, L. [Departmento de Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007, Oviedo (Spain); Tejedor, M. [Departmento de Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007, Oviedo (Spain)

    2004-12-31

    Magnetoimpedance effect was used as a tool to investigate the effectiveness of the method to induce magnetic anisotropy by applying a DC magnetic field during the melt spinning process in amorphous magnetic ribbons. Amorphous ribbons of composition Co{sub 69}Fe{sub 4}Si{sub 15}B{sub 12} were melt spun with and without applying the DC field in order to compare the results. From the different magnetoimpedance response to the external field in both kinds of ribbons, the induced magnetic anisotropy can be studied. Magnetoimpedance demonstrates to be a fine instrument to detect small changes of magnetic anisotropy and it is a good method to be employed in very narrow ribbons where other techniques are ineffective or unfeasible.

  6. High temperature (900-1300 C) mechanical behaviour of dendritic web grown silicon ribbons - Strain rate and temperature dependence of the yield stress

    Science.gov (United States)

    Mathews, V. K.; Gross, T. S.

    1987-01-01

    The mechanical behavior of dendritic web Si ribbons close the melting point was studied experimentally. The goal of the study was to generate data for modeling the generation of stresses and dislocation structures during growth of dendritic web Si ribbons, thereby permitting modifications to the production process, i.e., the temperature profile, to lower production costs for the photovoltaic ribbons. A laser was used to cut specimens in the direction of growth of sample ribbons, which were then subjected to tensile tests at temperatures up to 1300 C in an Ar atmosphere. The tensile strengths of the samples increased when the temperature rose above 1200 C, a phenomena which was attributed to the diffusion of oxygen atoms to the quasi-dislocation sites. The migration to the potential dislocations sites effectively locked the dislocations.

  7. Martensitic transformation and magnetocaloric properties in Ni40.4Mn46.5Sn10.9Sb2.2 ribbons

    Science.gov (United States)

    Xuan, H. C.; Zhang, T.; Wu, Y. F.; Xu, Y. K.; Li, H.; Han, P. D.; Du, Y. W.; Zhang, C. L.

    2017-01-01

    The Ni40.4Mn46.5Sn10.9Sb2.2 ribbons were prepared by melt-spun method. The martensitic transformation (MT) and magnetocaloric effect in melt-spun and annealed Ni40.4Mn46.5Sn10.9Sb2.2 ribbons were investigated. After the heat treatment, the MT temperature increases obviously in the annealed ribbons. The large values of magnetic entropy changes and the effective refrigerant capacity around the MT and Curie temperature of the austenite are found to be 30.9 and -2.2 J/kg K, 70.6 and 132.6 J/kg, respectively, under the field change of 30 kOe for the annealed ribbons. The annealing effect on the MT and magnetocaloric effect, together with the origin of the large magnetic entropy changes, has been discussed in this paper.

  8. The Use of Glass-fibers Ribbon and Composite for Prosthetic Restoration of Missing Primary Teeth-Laboratory and Clinical Research

    OpenAIRE

    Zilberman, Uri; Lasilla, Lippo

    2014-01-01

    Very few modalities can be used for restoring missing primary anterior teeth, although the impact of missing anterior teeth during early childhood can be harmful. In the permanent dentition the use of glass-fibers ribbon and composite materials are frequently used for restoring missing teeth with no or minimal preparation. The purpose of this study was to examine the possibility to use the glass-fibers ribbon (ever-Stick from GC Corporation, Japan) together with esthetic composite materials (...

  9. Web-dendritic ribbon growth. Quarterly report, 1 January 1976--31 March 1976. USC solar report No. Q-2

    Energy Technology Data Exchange (ETDEWEB)

    Hilborn, R.B. Jr.; Faust, J.W. Jr.

    1976-03-17

    The purpose of this investigation is to develop web-dendritic process methods that will: (1) minimize the cost of processing silicon into ribbons of solar cell quality with a terrestrial energy conversion efficiency greater than 10 percent, and (2) be suitable for large quantity production. The report for this second quarter describes the work of the program during this period and presents the plan for the program for the full length of the contract. Work is described on: (1) the procedures used to calibrate and operate the web-dendritic growth furnace; (2) use of the furnace to grow web-dendritic ribbon; (3) considerations applied for the thermal analysis and modeling of the web-dendritic growth system; and (4) procedures, facilities, and initial results for the structural and electrical characterization of web material. (WDM)

  10. Electronic structure and trajectory control of Dirac fermions in graphene ribbons under the competition between electric and magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Mou, E-mail: yangmou1222@gmail.com [Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Cui, Yan; Wang, Rui-Qiang; Zhao, Hong-Bo [Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China)

    2012-03-05

    We investigate the electronic structure of graphene ribbons under the competition between lateral electric and normal magnetic fields. The squeezing of quantum level spacings caused by either field is studied. Based on the knowledge of the dispersion under both fields, we analyze the electronic trajectories near the junctions of different electric and magnetic fields configurations. The junctions can split and join electron beams, and the conductance is quite robust against disorder near the junction interfaces. These junction devices can be used as bricks for building more complicated interference devices. -- Highlights: ► Unified physical picture of graphene ribbon under electric and magnetic fields is provided. ► Squeezing of level spacings caused by electric and magnetic fields is investigated. ► Graphene devices for electron beam split and joint are proposed.

  11. What Task Designers Do.

    Science.gov (United States)

    Johnson, Keith

    2000-01-01

    Describes a research project that is concerned with the design procedures followed by those engaged in designing pedagogic tasks for use in classrooms. Focuses on the part of the project that involves actual observation of designers in the process of developing one specific task for class use. Findings are presented under three headers: control…

  12. Giant magnetoimpedance effect in Fe75.5Cu1Nb3Si13.5B7 ribbon/FeGa film composite

    Science.gov (United States)

    Zhang, Yi; Gan, Tao; Wang, Tao; Wang, Feifei; Shi, Wangzhou

    2016-11-01

    Optimized giant magnetoimpedance effect of Fe75.5Cu1Nb3Si13.5B7 amorphous ribbon/Fe80Ga20 film composites has been investigated. FeCuNbSiB amorphous ribbons as the substrates are commercially available, magnetostrictive FeGa films are deposited on one or both sides of the ribbons by ion-beam sputtering. Compared with the GMI curves without FeGa layer, the GMI effect of FeCuNbSiB amorphous ribbon has been obviously improved with FeGa film covered (from 4% to 16%). Moreover, the details exhibit an interesting phenomenon: at a certain frequency, when the FeGa film covered on one side of the ribbon, the GMI ratio decreases with the thickness of the FeGa film; however, when the FeGa films covered on both sides of the ribbon, the GMI ratio increases with the thickness of the FeGa film. We mainly attribute the reason to strain-induced anisotropy, which is induced by magnetostrictive effect under a longitudinal applied magnetic field.

  13. Off-diagonal magnetoimpedance effect in field quenched Co{sub 69}Fe{sub 4}Si{sub 15}B{sub 12} amorphous ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, T.; Vega, V.; Santos, J.D.; Perez, M.J.; Prida, V.M.; Sanchez, M.L.; Hernando, B. [Universidad de Oviedo, Departamento de Fisica (Spain); Escoda, L.; Sunol, J.J. [Universidad de Girona, Departament de Fisica (Spain)

    2011-10-15

    In this work, the off-diagonal magnetoimpedance (MI) effect in two types of Co{sub 69}Fe{sub 4}Si{sub 15}B{sub 12} amorphous ribbons was measured. One type of ribbons was obtained by means of the conventional melt spinning technique. The other type of ribbons was obtained by the same procedure but with an applied transverse bias magnetic field, in order to induce a transverse anisotropy across the ribbon plane. According to our results, this field quenching procedure induces a small and homogeneously distributed anisotropy that improves the off-diagonal impedance response in all the frequency range here measured. In the as-quenched ribbon without field, slightly asymmetric two-peak behaviour of the field depending off-diagonal impedance at a frequency higher than its corresponding relaxation frequency has been observed. This can be related to the coupling among ribbon layers with different magnitude and/or orientation of the anisotropy induced by the developed stresses during the fabrication process. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Ecology of Blue Straggler Stars

    CERN Document Server

    Boffin, H M J; Beccari, G

    2014-01-01

    The existence of blue straggler stars (BSS), which appear younger, hotter, and more massive than their siblings, is at odds with a simple picture of stellar evolution, as such stars should have exhausted their nuclear fuel and evolved long ago to become cooling white dwarfs. As such, BSS could just be some quirks but in fact their understanding requires a deep knowledge of many different areas in astronomy, from stellar evolution through cluster dynamics, from chemical abundances to stellar populations. In November 2012, a workshop on this important topic took place at the ESO Chilean headquarters in Santiago. The many topics covered at this workshop were introduced by very comprehensive invited reviews, providing a unique and insightful view on the field. These reviews have now become chapters of the first ever book on BSS.

  15. Liquid biofuels from blue biomass

    DEFF Research Database (Denmark)

    Kádár, Zsófia; Jensen, Annette Eva; Bangsø Nielsen, Henrik

    2011-01-01

    medium, light as energy source and they capture CO2 for the synthesis of new organic material, thus can grow on non-agricultural land, without increasing food prices, or using fresh water. Due to all these advantages in addition to very high biomass yield with high carbohydrate content, macroalgaes can......Marine (blue) biomasses, such as macroalgaes, represent a huge unexploited amount of biomass. With their various chemical compositions, macroalgaes can be a potential substrate for food, feed, biomaterials, pharmaceuticals, health care products and also for bioenergy. Algae use seawater as a growth...... be the well suited candidates as feedstock for biofuel production in the future. The aim of our studies is to examine the possibility producing liquid biofuel (ethanol and butanol) from macroalgaes....

  16. Supporting complex search tasks

    DEFF Research Database (Denmark)

    Gäde, Maria; Hall, Mark; Huurdeman, Hugo;

    2015-01-01

    There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks......, is fragmented at best. The workshop addressed the many open research questions: What are the obvious use cases and applications of complex search? What are essential features of work tasks and search tasks to take into account? And how do these evolve over time? With a multitude of information, varying from...... introductory to specialized, and from authoritative to speculative or opinionated, when to show what sources of information? How does the information seeking process evolve and what are relevant differences between different stages? With complex task and search process management, blending searching, browsing...

  17. Supporting complex search tasks

    DEFF Research Database (Denmark)

    Gäde, Maria; Hall, Mark; Huurdeman, Hugo

    2015-01-01

    There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks, is fragme......There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks......, and recommendations, and supporting exploratory search to sensemaking and analytics, UI and UX design pose an overconstrained challenge. How do we know that our approach is any good? Supporting complex search task requires new collaborations across the whole field of IR, and the proposed workshop will bring together...

  18. Giant magnetoimpedance effect in melt-spun Co-based amorphous ribbons and wires with induced magnetic anisotropy

    Science.gov (United States)

    Tiberto, P.; Vinai, F.; Rampado, O.; Chiriac, H.; Ovari, T. A.

    1999-05-01

    GMI in Co 68.25Fe 4.5Si 12.25B 15 melt-spun amorphous wires and ribbons has been studied. Selected samples have been submitted to DC Joule-heating to induce circular and transverse magnetic anisotropy. Hysteresis loops have been measured using a fluxmetric technique. The results were interpreted in terms of circumferential and transverse permeability correlated with the magnetic domain structure.

  19. Magnetostructural transitions in Mn-rich Heusler Mn–Ni–In melt-spun ribbons with enhanced magnetocaloric effect

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hongwei; Feng, Shutong; Ren, Jian [State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200072 (China); Laboratory for Microstructures, Shanghai University, Shanghai 200072 (China); Zhai, Qijie; Fu, Jianxun [State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200072 (China); Luo, Zhiping [Department of Chemistry and Physics, Fayetteville State University, Fayetteville, NC 28301 (United States); Zheng, Hongxing, E-mail: hxzheng@shu.edu.cn [State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200072 (China); Laboratory for Microstructures, Shanghai University, Shanghai 200072 (China)

    2015-10-01

    The magnetostructural transition behavior and magnetocaloric effect of Mn-rich Heusler Mn–Ni–In melt-spun ribbons have been investigated in the present study. Experimental results showed that the martensitic transition temperatures decreased by substituting small amounts of Ni with Mn in Mn{sub 49+x}Ni{sub 42−x}In{sub 9} (x=0,1,2). Within a temperature range from 100 K to 380 K, the Mn{sub 49}Ni{sub 41}In{sub 9} underwent a martensitic transformation from a paramagnetic L2{sub 1}-type cubic austenite to a ferromagnetic modulated fourteen-layered monoclinic (14M) martensite, followed with a ferromagnetic→weak-magnetic transition in martensite upon cooling. While for both Mn{sub 50}Ni{sub 41}In{sub 9} and Mn{sub 51}Ni{sub 40}In{sub 9}, the paramagnetic→ferromagnetic transition in austenite occurred prior to the martensitic transformation upon cooling. Under a magnetic field change of 30 kOe, the maximum magnetic entropy changes of the Mn{sub 50}Ni{sub 41}In{sub 9} melt-spun ribbons were found to be 5.7 J/kg K and −2.3 J/kg K in the vicinity of martensitic transformation and magnetic transition of austenite, respectively. An enhanced total effective refrigeration capacity as high as 184.2 J/kg was obtained in the Mn{sub 50}Ni{sub 41}In{sub 9} melt-spun ribbons. - Highlights: • Mn-rich Heusler Mn–Ni–In melt-spun ribbons were investigated in the present study. • The compositional dependence on the magnetostructural transition behavior was clarified. • An enhanced refrigeration capacity as high as 184.2 J/kg was obtained in Mn{sub 50}Ni{sub 41}In{sub 9}.

  20. Magnetostructural phase transition in off-stoichiometric Ni–Mn–In Heusler alloy ribbons with low In content

    Energy Technology Data Exchange (ETDEWEB)

    González-Legarreta, L. [Dept. de Física, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); González-Alonso, D. [Facultat de Física, Departament d’Estructura i Constituents de la Matèria, Universitat de Barcelona, Diag. 647, E-08028 Barcelona (Spain); Rosa, W.O. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150 Urca., 22290-180 Rio de Janeiro, RJ (Brazil); Caballero-Flores, R. [Dept. de Física, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Suñol, J.J. [Universidad de Girona, Montilivi edifici PII, Lluís Santaló s/n. 17003 Girona (Spain); González, J. [Department of Materials Physics, Faculty of Chemistry, University of the Basque Country, 20018 San Sebastian (Spain); Hernando, B. [Dept. de Física, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain)

    2015-06-01

    We report features of microstructure, martensitic transformation, magnetic properties and magnetocaloric effect in three off-stoichiometric Ni{sub 45}Mn{sub 44}In{sub 11}, Ni{sub 47}Mn{sub 41}In{sub 12}and Ni{sub 48}Mn{sub 39}In{sub 13} (nominal-compositions) alloys ribbons. They were selected in the 7.8ribbons is also evidenced. - Highlights: • Three off-stoiquiometric Ni–Mn–In Heusler alloys ribbons with low In content were prepared by melt spinning. • A drastic decrease in magnetization for the two alloys with e/a=7.9 and 8.0 in comparison with the alloy showing e/a=7.8 with less Ni content. • High spin freezing temperature around 300 K for the two alloys with e/a=7.9 and 8.0. • Exchange bias field at 5 K about 1.3 kOe and 1.8 kOe for alloys with a high at% of Ni, but 0.012 kOe for the ribbon with less Ni content. • Magnetocaloric effect enhanced for the alloy with less Ni content.

  1. Magnetic-field-induced strain in Ni{sub 2}MnGa melt-spun ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Algarabel, P.A. E-mail: algarabe@posta.unizar.es; Magen, C.; Morellon, L.; Ibarra, M.R.; Albertini, F.; Magnani, N.; Paoluzi, A.; Pareti, L.; Pasquale, M.; Besseghini, S

    2004-05-01

    Linear thermal expansion (300-350 K) and magnetostriction measurements in magnetic fields up to 15 kOe have been performed on a Ni{sub 2}MnGa melt-spun ribbon. The magnetic-field-induced strain has been studied on a field-cooling process through the martensitic transformation and shows a maximum as a function of the applied field. This previously unreported behaviour is discussed.

  2. Initial Magnetization Curve and Hardening Mechanism in the Nanocomposite Nd8Fe85Nb1B6 Ribbon

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The melt-spun Nd8Fe85Nb1B6 ribbon was prepared by the single roller method with the tangential speed of 20 m/s. A mixture of Nd2Fe14B and α-Fe phases with the average crystalline grain size of about 20 nm was found to exist in the as-quenched ribbons. The initial magnetization curve of the nanocomposite Nd8Fe85Nb1B6 ribbon can be divided into four sections by the inflection points on it. The magnetically hardening mechanism corresponding to each section was investigated. The initial susceptibility of the Nd8Fe85Nb1B6 ribbon is higher than that of the Nd15Fe85B9 powder, which may be attributed to the reversible magnetization rotation in the central region not influenced by the exchange-coupling effect within the α-Fe grains.The above-mentioned magnetization rotation leads to the formation of equilibrium 180 deg. domain walls at the boundaries of the α-Fe grains. With the increase of applied field, these domain walls are compressed reversibly towards the Nd2Fe14B grains and eventually invade into them.The irreversible movement of the domain walls in the Nd2Fe14B grains accounts for the steepest growth of magnetization with the applied field. Finally, the magnetically inhomogeneous “core regions” are formed in the Nd2Fe14B grains, and the magnetization rotation in these“core regions”indicates the end of the whole initial saturation process.

  3. Large-scale conversion of helical-ribbon carbon nanofibers to a variety of graphene-related materials

    OpenAIRE

    Lobato Ortega, Belén; Merino, C.; Barranco, V.; Álvarez Centeno, Teresa

    2016-01-01

    Helical-ribbon carbon nanofibers produced on an industrial scale were successfully converted in highly functionalized graphene nanoplatelets by using a slight modification of the Hummers oxidation method. The duration of the oxidative process severely affected the interlayer spacing in the resulting nanoplatelets and, consequently, they showed very different exfoliation behavior. Therefore, it was possible to obtain a variety of graphene-related products through their ultrasonication or therm...

  4. Hydrogen passivation of defects and rapid thermal processing for high-efficiency silicon ribbon solar cells

    Science.gov (United States)

    Jeong, Ji-Weon

    2002-01-01

    The use of photovoltaic (PV) system offers a unique opportunity to solve the energy and the environmental problems simultaneously because solar energy is free and can be directly converted into electrical energy by solar cells without any undesirable impact on the environment. In spite of the many advantages, PV still accounts for less than 0.05% of the current U.S. energy portfolio. This is mainly because PV is 2-4 times more expensive than traditional energy sources. PV modules should cost about $1/W to produce electricity at a rate of 6¢/kWh and to compete with fossil fuels. Since Si material accounts for ˜40% of the cost of current Si PV modules, the use of low-cost Si substrate is critical for cost reduction. Edge-defined film-fed grown (EFG) Si ribbon is the focus as substrate materials for this research because it is one of the most promising for low-cost PV. However, as-grown EFG Si has a lot of impurities and crystal defects resulted from the Si feedstock and its growth system, which reduce the bulk lifetime of less than 3 ms. In this research, first, the requirements for achieving 16% efficiency have been established using computer model simulations. To improve the bulk lifetime, manufacturable P and Al gettering techniques are developed to remove the lifetime-killing impurities from the active to inactive device regions. PECVD SiN-induced hydrogen defect passivation is investigated and maximized through the fundamental understanding of the role of Al, the impact of RTP firing, and the difference between two PECVD SiN films. For low-cost contact formation, a novel RTP firing process is developed for high-quality screen-printed contacts and Al-BSF. Finally, a complete process sequence that involves the optimal conditions for defect passivation and contacts is developed to produce ˜16% efficiency on screen-printed EFG Si solar cells, which is the highest efficiency for any screen-printed Si ribbon solar cells to date.

  5. Blue Skies, Coffee Creamer, and Rayleigh Scattering

    Science.gov (United States)

    Liebl, Michael

    2010-01-01

    The first physical explanation of Earths blue sky was fashioned in 1871 by Lord Rayleigh. Many discussions of Rayleigh scattering and approaches to studying it both in and out of the classroom are available. Rayleigh scattering accounts for the blue color of the sky and the orange/red color of the Sun near sunset and sunrise, and a number of…

  6. Simple and efficient modeling of the E-k relationship and low-field mobility in Graphene Nano-Ribbons

    Science.gov (United States)

    Bresciani, Marco; Palestri, Pierpaolo; Esseni, David; Selmi, Luca

    2010-09-01

    This paper proposes a simple analytical formulation for the dispersion relationship of extended electronic states in Graphene Nano-Ribbons (GNRs). The model has been validated by comparison with Tight-Binding calculation of GNRs in the presence of edge disorder. The model is suited for inclusion in semiclassical models for GNRs featuring widths down to approximately 2 nm. Monte-Carlo simulations accounting for phonons and edge roughness scattering are then used to understand the ribbon width of the low-field mobility. The mechanisms responsible for the low mobility values measured in narrow ribbons compared to graphene sheets are the increased phonon scattering rate and mobility effective mass due to the strong band structure modification induced by the reduced lateral dimensions and the increased scattering with the edges. However, scattering with phonons and with edges is not sufficient to reproduce the experimental mobility on insulating substrates, suggesting that the effect of remote polar phonons originating in the substrate can be significant in graphene based devices.

  7. THE COCHlEAR RIBBON SYNAPTIC RESPONSE TO AMINOGIYCOSIDE OTOTOXICITY IN C57BL/6J MICE

    Institute of Scientific and Technical Information of China (English)

    LIU Ke; ZHAO Ning; SHI Chuang; WU Nan; LIU Huizhan; ZHANG Yue; YANG Weiyan; YANG Shiming

    2014-01-01

    Objective To investigate the early change of cochlear ribbon synapses on inner hair cells in response to aminoglycoside ototoxicity. Methods C57BL/6J mice received intraperitoneal injection of gentamicin (100 mg/kg/day), and the apical coil organ of Corti was examined on the 4th, 7th and 10th day (n=10). Litter-mates without gentamicin treatment served as controls (n=10). RIBEYE on the presynaptic membrane and AMPA receptors on the postsynaptic membrane were labeled with CtBP2 or GluR2/3 respectively. Three di-mension reconstruction was conducted using the 3DS MAX 8.0 software. Results There were no disruptions of outer or inner hair cells in all groups. However, the number of ribbon synapses on cochlear inner hair cells increased significantly within 7 days after gentamicin exposure (P<0.01), followed by a significant de-crease after 7 days.Conclusion During the early stage of aminoglycoside ototoxicity, increased population of cochlear ribbon synapses may indicate a significant down-regulation of synaptic function.

  8. Kane-Mele Hubbard model on a zigzag ribbon: Stability of the topological edge states and quantum phase transitions

    Science.gov (United States)

    Chung, Chung-Hou; Lee, Der-Hau; Chao, Sung-Po

    2014-07-01

    We study the quantum phases and phase transitions of the Kane-Mele Hubbard (KMH) model on a zigzag ribbon of honeycomb lattice at a finite size via the weak-coupling renormalization group (RG) approach. In the noninteracting limit, the Kane-Mele (KM) model is known to support topological edge states where electrons show helical property with orientations of the spin and momentum being locked. The effective interedge hopping terms are generated due to finite-size effect. In the presence of an on-site Coulomb (Hubbard) interaction and the interedge hoppings, special focus is put on the stability of the topological edge states (TI phase) in the KMH model against (i) the charge and spin gaped (II) phase, (ii) the charge gaped but spin gapless (IC) phase, and (iii) the spin gaped but charge gapless (CI) phase depending on the number (even/odd) of the zigzag ribbons, doping level (electron filling factor) and the ratio of the Coulomb interaction to the interedge tunneling. We discuss different phase diagrams for even and odd numbers of zigzag ribbons. We find the TI-CI, II-IC, and II-CI quantum phase transitions are of the Kosterlitz-Thouless (KT) type. By computing various correlation functions, we further analyze the nature and leading instabilities of these phases. The relevance of our results for graphene is discussed.

  9. {gamma}-Fe phase plasma-induced on the surface of thin S3A alloy ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Cabral-Prieto, A., E-mail: agustin.cabral@inin.gob.mx; Garcia-Sosa, I., E-mail: irma.garcia@inin.gob.mx [Instituto Nacional de Investigaciones Nucleares, Departamento de Quimica (Mexico); Nava, N., E-mail: tnava@imp.mx [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas (Mexico); Camps, E., E-mail: enrique.camps@inin.gob.mx; Escobar, Luis, E-mail: luis.escobar@inin.gov.mx [Instituto Nacional de Investigaciones Nucleares, Departamento de Quimica (Mexico); Lopez-Castanarez, R., E-mail: rlc@anuies.mx; Olea-Cardoso, O., E-mail: olc@anuies.mx [Universidad Autonoma del Edo. de Mexico, Facultad de Quimica (Mexico)

    2011-11-15

    Amorphous alloy ribbons of Fe{sub 77}Cr{sub 2}B{sub 16}Si{sub 5} were exposed to cold plasmas of N{sub 2} and Ar-N{sub 2} at temperatures lower than T{sub x} = 808 K. The conversion X-ray Moessbauer spectra of the plasma-exposed ribbons consist of a singlet and a broadened magnetic sextet. The singlet with isomer shift {delta} = -0.11 mm/s can be assigned to {gamma}-Fe austenite phase. Minor bulk magnetic changes in the alloy were measured as a consequence of these treatments; e.g. the relative intensities A23 of the transmission Moessbauer spectra of the untreated and treated samples, were 3.22 and 3.56, respectively, the B{sub hf} values changed from 22.9 T (untreated sample) to 22.4 T (plasma treated samples). Unexpectedly, the {gamma}-Fe phase can also be produced by simply heating the alloy ribbons under N{sub 2} flux at temperatures as low as 423 K. Moessbauer data of the crystallized samples are also reported, and a qualitative assessment on the mechanical properties of the Fe{sub 77}Cr{sub 2}B{sub 16}Si{sub 5} alloy associated with the plasma and/or temperature surface induced {gamma}-Fe phase is given.

  10. STRUCTURE OF THE INTERSTELLAR BOUNDARY EXPLORER RIBBON FROM SECONDARY CHARGE-EXCHANGE AT THE SOLAR–INTERSTELLAR INTERFACE

    Energy Technology Data Exchange (ETDEWEB)

    Zirnstein, E. J.; McComas, D. J. [Southwest Research Institute, San Antonio, TX 78228 (United States); Heerikhuisen, J., E-mail: ezirnstein@swri.edu, E-mail: dmccomas@swri.edu, E-mail: jacob.heerikhuisen@uah.edu [Department of Space Science and Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2015-05-01

    In 2009, the Interstellar Boundary Explorer discovered a bright “ribbon” of energetic neutral atom (ENA) flux in the energy range ≤0.4–6 keV, encircling a large portion of the sky. This observation was not previously predicted by any models or theories, and since its discovery, it has been the subject of numerous studies of its origin and properties. One of the most studied mechanisms for its creation is the “secondary ENA” process. Here, solar wind ions, neutralized by charge-exchange with interstellar atoms, propagate outside the heliopause; experience two charge-exchange events in the dense outer heliosheath; and then propagate back inside the heliosphere, preferentially in the direction perpendicular to the local interstellar magnetic field. This process has been extensively analyzed using state-of-the-art modeling and simulation techniques, but it has been difficult to visualize. In this Letter, we show the three-dimensional structure of the source of the ribbon, providing a physical picture of the spatial and energy scales over which the secondary ENA process occurs. These results help us understand how the ribbon is generated and further supports a secondary ENA process as the leading ribbon source mechanism.

  11. Scatter-free pickup ions beyond the heliopause as a model for the Interstellar Boundary Explorer (IBEX) ribbon

    CERN Document Server

    Chalov, S V; McComas, D; Izmodenov, V V; Malama, Yu G; Schwadron, N

    2010-01-01

    We present new kinetic-gasdynamic model of the solar wind interaction with the local interstellar medium. The model incorporates several processes suggested by McComas et al. (2009) for the origin of the heliospheric ENA ribbon -- the most prominent feature seen in the all sky maps of heliospheric ENAs discovered by the Interstellar Boundary Explorer (IBEX). The ribbon is a region of enhanced fluxes of ENAs crossing almost the entire sky. Soon after the ribbon's discovery it was realized (McComas et al., 2009) that the enhancement of the fluxes could be in the directions where the radial component of the interstellar magnetic field around the heliopause is close to zero (Schwadron et al., 2009). Our model includes secondary charge exchange of the interstellar H atoms with the interstellar pickup protons outside the heliopause and is a further advancement of the kinetic-gasdynamic model by Malama et al. (2006) where pickup protons were treated as a separate kinetic component. Izmodenov et al. (2009) have shown...

  12. Task-baseret kommunikativ sprogundervisning

    DEFF Research Database (Denmark)

    Pedersen, Michael Svendsen

    2015-01-01

    Definition af task-baseret sprogundervisning, kriterier for task. Forskning i Second Language Acquisition med brug af task, tilrettelæggelse af task-baseret kommunikativ undervisning. Begrænsninger i og perspektiver for videreudvikling af task-baseret sprogundervising-......Definition af task-baseret sprogundervisning, kriterier for task. Forskning i Second Language Acquisition med brug af task, tilrettelæggelse af task-baseret kommunikativ undervisning. Begrænsninger i og perspektiver for videreudvikling af task-baseret sprogundervising-...

  13. What are task-sets: a single, integrated representation or a collection of multiple control representations?

    Directory of Open Access Journals (Sweden)

    Dragan eRangelov

    2013-09-01

    Full Text Available Performing two randomly alternating tasks typically results in higher reaction times (RTs following a task switch, relative to a task repetition. These task switch costs (TSC reflect processes of switching between control settings for different tasks. The present study investigated whether task sets operate as a single, integrated representation or as an agglomeration of relatively independent components. In a cued task switch paradigm, target detection (present/absent and discrimination (blue/green/right-/left-tilted tasks alternated randomly across trials. The target was either a color or an orientation singleton among homogeneous distractors. Across two trials, the task and target-defining dimension repeated or changed randomly. For task switch trials, agglomerated task sets predict a difference between dimension changes and repetitions: joint task and dimension switches require full task set reconfiguration, while dimension repetitions permit re-using some control settings from the previous trial. By contrast, integrated task sets always require full switches, predicting dimension repetition effects (DREs to be absent across task switches. RT analyses showed significant DREs across task switches as well as repetitions supporting the notion of agglomerated task sets. Additionally, two event-related potentials (ERP were analyzed: the Posterior-Contralateral-Negativity (PCN indexing spatial selection dynamics, and the Sustained-Posterior-Contralateral-Negativity (SPCN indexing post-selective perceptual/semantic analysis. Significant DREs across task switches were observed for both the PCN and SPCN components. Together, DREs across task switches for RTs and two functionally distinct ERP components suggest that re-using control settings across different tasks is possible. The results thus support the ‘agglomerated-task-set’ hypothesis, and are inconsistent with ‘integrated task sets’.

  14. Integrable Nonlinear Schrödinger System on a Triangular-Lattice Ribbon

    Science.gov (United States)

    Vakhnenko, Oleksiy O.

    2015-01-01

    An integrable nonlinear Schrödinger system on a triangular-lattice ribbon, whose geometric configuration is similar to that of (1,1) armchair boron nanotube, is studied in detail. The system Hamiltonian formulation is shown to underline an essentially nontrivial Poisson structure associated with four basic field variables appearing as nearly amplitudes of the probability to find the lattice sites being excited and with two concomitant field variables maintaining the finite background. The coupling parameters of the system are allowed to be complex-valued ones thus permitting to model external magnetic fluxes threading the elementary plackets of a lattice in terms of Peierls phases. An alternative version of zero-curvature representation given in terms of 2 × 2 auxiliary spectral and evolution matrices is proved to support the constructive integrability of the system by means of Darboux-Bäcklund dressing method. In the framework of Darboux approach the one-soliton solution is found explicitly and analyzed with special attention to the principal differences between the bare and physical soliton parameters.

  15. Assessment of a postdeployment Yellow Ribbon Reintegration Program for National Guard members and supporters.

    Science.gov (United States)

    Scherrer, Jeffrey F; Widner, Greg; Shroff, Manan; Matthieu, Monica; Balan, Sundari; van den Berk-Clark, Carissa; Price, Rumi K

    2014-11-01

    The Yellow Ribbon Reintegration Program (YRRP) was created to meet the needs of National Guard members and their families throughout the deployment cycle. This study examined the perceived utility of the YRRP's delivery of information and assistance during the postdeployment reintegration period by National Guard members and accompanying supporters who were mostly spouses. Over 22 months, from 10 YRRP events, 683 service members and 411 supporters completed questionnaires immediately after the YRRP. We analyzed questions on information and avenues for help, timeliness and concerns related to education, employment, legal, family, and health. Service members and supporters most often endorsed information delivery on education being met (76.8% and 78.2%, respectively) and were least likely to endorse legal information delivery (63.5% and 60%, respectively). Significantly more supporters than service members (p < 0.0001) reported that the YRRP was the first time they learned of available services across all domains. Service members were significantly more likely than supporters to report concerns about education, employment, and health, while supporters were significantly more likely to report concerns about family. Results suggest the YRRP fills gaps in supporter knowledge and provides needed information and resources to most National Guard families 2 to 4 months after a deployment.

  16. Structural and Magnetic Properties of Fe Doped Mn-Ga Ribbons

    Directory of Open Access Journals (Sweden)

    Sarafidis C.

    2014-07-01

    Full Text Available In the present work we study the effect on structural and magnetic properties due to the introduction of Fe in Mn2Ga system. Mn0.7-xFexGa0.3 (x = 0.1 to 0.3 alloys were prepared with Ar arc-melting as base materials which were subsequently converted to ribbons using melt-spinning technique with velocity ranged from 20 to 35 m/s. Some of the materials were heat treated in a temperature range from 550 to 850 °C and for different time span, from 10 minutes to 1 hour. Alloys were studied by various characterization techniques (EDX, X-ray diffraction, magnetization versus temperature and field. The magnetic properties are improved with the increase of Fe content, Ms rises almost an order of magnitude from 0.05 per formula unit to 0.5 μB while low temperature coercivity reached 3.5 kOe. The temperature and duration of the thermal processing also plays a significant role. Two phases were detected, the one being stable above 973 K. The materials present two main Curie temperatures, one above 500 K and one transition below room temperature.

  17. Hydrogen-bonded Supramolecular Rosette Ribbon Constructed from Melamine with Isophthalic Acid

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiu-Lian

    2008-01-01

    The new complex of melamine (MA) with isophthalie acid (H2IA), [(HMA+)-(HIA-)]·2H2O, has been prepared and its structure was characterized by X-ray crystallography.The crystal is of triclinic, space group P1 with a = 7.0228(6), b = 9.1706(8), c = 12.170(1) A, α =95.337(2), β = 105.247(2), γ = 97.813(2)°, V= 742.3(1) A3, Mr= 328.30, Z= 2,Dc = 1.469 g/cm3,λ = 0.71073 A, μ(MoKa) = 0.121 mm-1 and F(000) = 344. The structure was refined to R =0.0389 and wR = 0.1093 for 2513 observed reflections with Ⅰ 2σ(Ⅰ). Melamine dimer and isophthalic acid anion are interlinked by N-H…N and N-H…O hydrogen bonds, resulting in a 1D rosette ribbon in which water molecules and amino groups are self-assembled into quasi-hexagonal patterns.

  18. A possible generation mechanism for the IBEX ribbon from outside the heliosphere

    CERN Document Server

    Grzedzielski, S; Czechowski, A; Funsten, H O; McComas, D J; Schwadron, N A

    2010-01-01

    The brightest and most surprising feature in the first all-sky maps of Energetic Neutral Atoms (ENA) emissions (0.2-6 keV) produced by the Interstellar Boundary Explorer (IBEX) is an almost circular ribbon of a ~140{\\deg} opening angle, centered at (l,b) = (33{\\deg}, 55{\\deg}), covering the part of the celestial sphere with the lowest column densities of the Local Interstellar Cloud (LIC). We propose a novel interpretation of the IBEX results based on the idea of ENA produced by charge-exchange between the neutral H atoms at the nearby edge of the LIC and the hot protons of the Local Bubble (LB). These ENAs can reach the Sun's vicinity because of very low column density of the intervening LIC material. We show that a plane-parallel or slightly curved interface layer of contact between the LIC H atoms (n_H = 0.2 cm^-3, T = 6000-7000 K) and the LB protons (n_p = 0.005 cm^-3, T ~ 10^6 K), together with indirect contribution coming from multiply-scattered ENAs from the LB, may be able to explain both the shape of...

  19. Magnetostructural transition behavior in Fe-doped Heusler Mn-Ni-In ribbon materials

    Science.gov (United States)

    Li, Hongwei; Fang, Yue; Feng, Shutong; Zhai, Qijie; Luo, Zhiping; Zheng, Hongxing

    2016-11-01

    In the present work, we investigated magnetostructural transition behavior in Mn-rich Heusler Mn50-xFexNi41In9 (x=0, 1, 2, 3 at%) ribbon materials. Microstructural observations showed that substituting Mn with Fe in Mn50Ni41In9 led to striking grain refinement from ∼50 μm to 5-10 μm, and formation of a secondary phase when Fe content was increased up to 2 at%. Differential scanning calorimetric and thermomagnetic measurements indicated that a paramagnetic→ferromagnetic transition in austenite occurred first, followed with a weak-magnetic martensitic transition upon cooling for the Mn50-xFexNi41In9 (x=0, 1, 2). In case of Mn47Fe3Ni41In9, the martensitic transformation happened between paramagnetic austenite and weak-magnetic martensite, without the presence of the magnetic transition in austenite. The effective refrigeration capacity of Mn49Fe1Ni41In9 reached 137.1 J kg-1 under a magnetic field change of 30 kOe.

  20. Slipping magnetic reconnections with multiple flare ribbons during an X-class solar flare

    CERN Document Server

    Zheng, Ruisheng; Wang, Bing

    2016-01-01

    With the observations of the Solar Dynamics Observatory, we present the slipping magnetic reconnections with multiple flare ribbons (FRs) during an X1.2 eruptive flare on 2014 January 7. A center negative polarity was surrounded by several positive ones, and there appeared three FRs. The three FRs showed apparent slipping motions, and hook structures formed at their ends. Due to the moving footpoints of the erupting structures, one tight semi-circular hook disappeared after the slippage along its inner and outer edge, and coronal dimmings formed within the hook. The east hook also faded as a result of the magnetic reconnection between the arcades of a remote filament and a hot loop that was impulsively heated by the under flare loops. Our results are accordant with the slipping magnetic reconnection regime in 3D standard model for eruptive flares. We suggest that complex structures of the flare is likely a consequence of the more complex flux distribution in the photosphere, and the eruption involves at least...

  1. Why are flare ribbons generically elongated in configurations with magnetic null points?

    Science.gov (United States)

    Pontin, David Iain; Galsgaard, Klaus; Demoulin, Pascal

    2016-05-01

    Coronal magnetic null points exist in abundance as demonstrated by extrapolations of the coronal field, and have been inferred to be important for a broad range of energetic events. These null points and their associated separatrix and spine field lines represent discontinuities of the field line mapping, making them preferential locations for reconnection in the corona. In addition, the field line mapping in the vicinity of these null points exhibits strong gradients as measured by the “squashing factor”, Q. We demonstrate that the extension of the Q halos around the spine/fan footpoints is in general important for diagnosing the regions of the photosphere that are magnetically connected to any current layer that forms at the null. In light of this, we discuss the extent to which our results can be used to interpret the geometry of observed flare ribbons in events in which a coronal null is implicated. We conclude that together the physics in the vicinity of the null and how this is related to the extension of Q away from the spine/fan can be used in tandem to understand observational signatures of reconnection at coronal null points.

  2. Self-assembly of graphene ribbons by spontaneous self-tearing and peeling from a substrate

    Science.gov (United States)

    Annett, James; Cross, Graham L. W.

    2016-07-01

    Graphene and related two-dimensional materials have shown unusual and exceptional mechanical properties, with similarities to origami-like paper folding and kirigami-like cutting demonstrated. For paper analogues, a critical difference between macroscopic sheets and a two-dimensional solid is the molecular scale of the thin dimension of the latter, allowing the thermal activation of considerable out-of-plane motion. So far thermal activity has been shown to produce local wrinkles in a free graphene sheet that help in theoretically understanding its stability, for example, and give rise to unexpected long-range bending stiffness. Here we show that thermal activation can have a more marked effect on the behaviour of two-dimensional solids, leading to spontaneous and self-driven sliding, tearing and peeling from a substrate on scales approaching the macroscopic. We demonstrate that scalable nanoimprint-style contact techniques can nucleate and direct the parallel self-assembly of graphene ribbons of controlled shape in ambient conditions. We interpret our observations through a simple fracture-mechanics model that shows how thermodynamic forces drive the formation of the graphene-graphene interface in lieu of substrate contact with sufficient strength to peel and tear multilayer graphene sheets. Our results show how weak physical surface forces can be harnessed and focused by simple folded configurations of graphene to tear the strongest covalent bond. This effect may hold promise for the patterning and mechanical actuating of devices based on two-dimensional materials.

  3. Large group intervention for military reintegration: peer support & Yellow Ribbon enhancements.

    Science.gov (United States)

    Castellano, Cherie; Everly, George S

    2010-01-01

    University Behavioral HealthCare, University of Medicine and Dentistry of New Jersey in partnership with the New Jersey Department of Military & Veterans Affairs established a program entitled the "New Jersey Veterans Helpline," modeled after the "Cop 2 Cop Helpline," in 2005 to assist veterans and their families within the state. The events of September 11, 2001, demanded an unprecedented response to address the behavioral health care needs of first responders in New Jersey and highlighted the similarities amongst the military population in their response. Although the New Jersey Veterans Helpline program was initiated as a peer based helpline, the need for support in pre- and post-deployment quickly emerged. This paper describes the application of the Cop 2 Cop interventions with the Port Authority Police Department (PAPD) entitled "Acute Stress Management Reentry Program." This program was adapted and combined with Yellow Ribbon Guideline enhancements to create a "60 Day Resiliency & Reintegration Program" led by the New Jersey Veterans program to over 2,400 soldiers returning from war.

  4. Micelles versus Ribbons: How Congeners Drive the Self-Assembly of Acidic Sophorolipid Biosurfactants.

    Science.gov (United States)

    Dhasaiyan, Prabhu; Le Griel, Patrick; Roelants, Sophie; Redant, Emile; Van Bogaert, Inge N A; Prevost, Sylvain; Prasad, B L V; Baccile, Niki

    2017-03-17

    Sophorolipids (SLs), a class of microbially derived biosurfactants, are reported by different research groups to have different self-assembled structures (either micelles or giant ribbons) under the same conditions. Here we explore the reasons behind these contradictory results and attribute these differences to the role of specific congeners that are present in minute quantities. We show that a sample composed of a majority of oleic acid (C18:1) sophorolipid in the presence of only 0.5 % (or more) of congeners with stearic acid (C18:0) or linoleic acid (C18:2) results in the formation of micelles that are stable over long periods of time. Conversely, the presence of only 10 to 15 % of congeners with a stearic acid chain gives fibrillar structures instead of micelles. To study the mechanisms responsible, oleic acid SLs devoid of any other congeners were prepared. Very interestingly, this sample can self-assemble into either micelles or fibers depending on minute modifications to the self-assembly conditions. The findings are supported by light scattering, small-angle X-ray scattering, transmission electron microscopy under cryogenic conditions, high-pressure liquid chromatography, and NMR spectroscopy.

  5. Tetrodotoxin-producing Bacillus sp. from the ribbon worm (Nemertea) Cephalothrix simula (Iwata, 1952).

    Science.gov (United States)

    Magarlamov, Timur Yu; Beleneva, Irina A; Chernyshev, Alexey V; Kuhlevsky, Andrey D

    2014-07-01

    Specimens of the toxic ribbon worm Cephalothrix simula from the Sea of Japan were screened for tetrodotoxin-producing bacteria. A single TTX-producing bacterial strain (No 1839) was isolated from tissues of C. simula and studied by immunohistochemical methods (including immunoelectron and immunofluorescent microscopies) with anti-TTX antibodies. Sequencing of 16S rRNA gene of the strain 1839 showed that it is most likely Bacillus sp. CU040510-015 and Bacillus asahii. Based on its morphological and biochemical properties, however we suppose that the isolated Bacillus sp. 1839 should be classified as representing a new species. Microdistribution of TTX in bacterial cell was investigated under electron microscope by immunoenzymatic methods. TTX was concentrated in the forespore and free spores, but it was not detected in the vegetative cells of Bacillus sp. 1839. We suggest that release of free mature spores from sporangium of Bacillus sp. 1839 leads to appearance of toxin in tissues of C. simula. Confocal laser-scanning microscopy (CLSM) method with anti-TTX antibodies can be recommended for preliminary detection of apparent TTX accumulation.

  6. Passivated silicon ribbon solar cells and modules. Final report; Passivierte Siliciumfolien-Solarzellen und -module (PFS). Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, W.; Heit, W.; Lauinger, T.; Roth, P.; Schum, B.

    2000-06-01

    This project was organised into three main work packages. (a) The outcome of the characterisation of silicon materials and specially silicon ribbons was the elaboration of a specification for EFG (edge-defined film-fed growth) silicon wafers. Moreover, for final inspection of EFG solar cells, methods suitable for continuous operation were developed. RGS silicon ribbons were characterised together with institutes. (b) The solar cell development activities lead to the definition of a new simple process sequence and related continuous production techniques for the automated production of passivated silicon ribbon solar cells. Combined with the EFG wafer specification, the achieved results formed the base for the design of a new fully automated continuous pilot production line. The developed solar cell processing technologies were successfully approved in this line: Mean efficiencies of 14% for EFG silicon ribbon and 14.5 to 15% for cast multicrystalline silicon wafers were achieved. A main result of the module development was the elaboration of interconnection and encapsulation technologies suitable for EfG silicon ribbon solar cells. In addition, extensive studies of module failure mechanisms were successfully completed, thereby contributing to knowledge about module design for enhanced lifetime. (orig.) [German] In diesem Vorhaben wurden drei Schwerpunktthemen bearbeitet. (a) Die Materialcharakterisierung, insbesondere von Siliciumfolien, muendete in die Erstellung einer Spezifikation fuer EFG (edge-defined film-fed growth)-Siliciumfolien. Darueber hinaus wurden fuer die Endkontrolle von EFG-Siliciumfoliensolarzellen geeignete Durchlaufkonzepte und Pruefverfahren entwickelt. RGS-Folien wurden in Zusammenarbeit mit Instituten charakterisiert. (b) Die Solarzellenentwicklung fuehrte zu einer einfachen Prozessfolge und den zugehoerigen neuartigen Durchlaufverfahren fuer eine vollautomatische Herstellung von hocheffizienten passivierten Siliciumfoliensolarzellen

  7. Energy Efficient Task Light

    DEFF Research Database (Denmark)

    Logadottir, Asta; Ardkapan, Siamak Rahimi; Johnsen, Kjeld

    2014-01-01

    The objectives of this work is to develop a task light for office lighting that fulfils the minimum requirements of the European standard EN12464 - 1 : Light and lighting – Lighting of work places, Part 1: Indoor workplaces and the Danish standard DS 700 : Lys og belysning I arbejdsrum , or more...... specifically the requirements that apply to the work area and the immediate surrounding area. By providing a task light that fulfils the requirements for task lighting and the immediate surrounding area, the general lighting only needs to provide the illuminance levels required for background lighting...... and thereby a reduction in installed power for general lighting of about 40 % compared to the way illuminance levels are designed in an office environment in Denmark today. This lighting strategy is useful when the placement of the task area is not defined in the space before the lighting is design ed...

  8. Organizing Core Tasks

    DEFF Research Database (Denmark)

    Boll, Karen

    Civil servants conduct the work which makes welfare states functions on an everyday bases: Police men police, school teachers teach, and tax inspectors inspect. Focus in this paper is on the core tasks of tax inspectors. The paper argues that their core task of securing the collection of revenue...... has remained much the same within the last 10 years. However, how the core task has been organized has changed considerable under the influence of various “organizing devices”. The paper focusses on how organizing devices such as risk assessment, output-focus, effect orientation, and treatment...... projects influence the organization of core tasks within the tax administration. The paper shows that the organizational transformations based on the use of these devices have had consequences both for the overall collection of revenue and for the employees’ feeling of “making a difference”. All in all...

  9. Performing Task Integration

    DEFF Research Database (Denmark)

    Elkjaer, Bente; Nickelsen, Niels Christian Mossfeldt

    . Here cross-professional coordination of work was done by scheduled communication twice a day. When we proposed a way for further integration of tasks through an all-inclusive team organization, we were met with resistance. We use the study to discuss whether relational coordination theory is able to do...... away with differences regarding task definitions and working conditions as well as professional knowledge hierarchies and responsibilities for parts and wholes....

  10. Can greening of aquaculture sequester blue carbon?

    Science.gov (United States)

    Ahmed, Nesar; Bunting, Stuart W; Glaser, Marion; Flaherty, Mark S; Diana, James S

    2016-11-15

    Globally, blue carbon (i.e., carbon in coastal and marine ecosystems) emissions have been seriously augmented due to the devastating effects of anthropogenic pressures on coastal ecosystems including mangrove swamps, salt marshes, and seagrass meadows. The greening of aquaculture, however, including an ecosystem approach to Integrated Aquaculture-Agriculture (IAA) and Integrated Multi-Trophic Aquaculture (IMTA) could play a significant role in reversing this trend, enhancing coastal ecosystems, and sequestering blue carbon. Ponds within IAA farming systems sequester more carbon per unit area than conventional fish ponds, natural lakes, and inland seas. The translocation of shrimp culture from mangrove swamps to offshore IMTA could reduce mangrove loss, reverse blue carbon emissions, and in turn increase storage of blue carbon through restoration of mangroves. Moreover, offshore IMTA may create a barrier to trawl fishing which in turn could help restore seagrasses and further enhance blue carbon sequestration. Seaweed and shellfish culture within IMTA could also help to sequester more blue carbon. The greening of aquaculture could face several challenges that need to be addressed in order to realize substantial benefits from enhanced blue carbon sequestration and eventually contribute to global climate change mitigation.

  11. Quantitative analysis of the ribbon synapse number of cochlear inner hair cells in C57BL/6J mice using the three-dimensional modeling method

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In mammals,the ribbon synapses of cochlear inner hair cells are a synaptic structure of the first sensory nerve in the pathway of acoustical signal transmission to the acoustic center,and it is directly involved in voice coding and neurotransmitter release. It is difficult to quantitatively analyze the ribbon synaptic number only using an electron microscope,because the ribbon synaptic number is relatively limited and their location is deep. In this study,the specific presynaptic structure-RIBEYE,and non-specific postsynaptic structure-GluR 2 & 3 in C57BL/6J mouse basilar membrane samples were treated by immunofluorescent labeling. Serial section was performed on the samples using a laser scanning confocal microscope,and then the serial sections were used to build three-dimensional models using 3DS MAX software. Each fluorescein color pair indicates one synapse,so the number of ribbon synapses of inner hair cells is obtained. The spatial distribution and the number of ribbon synapses of cochlear inner hair cells were clearly shown in this experiment,and the mean number of ribbon synapses per inner hair cell was 16.10±1.03. Our results have demonstrated the number of ribbon synapses is accurately calculated by double immunofluorescent labeling to presynaptic and postsynaptic structures,serial sections obtained using a laser scanning confocal microscope,and three-dimensional modeling obtained using 3DS MAX software. The method above is feasible and has important significance for further exploring the mechanism of sensorineural deafness.

  12. Blue outliers among intermediate redshift quasars

    CERN Document Server

    Marziani, P; Stirpe, G M; Dultzin, D; Del Olmo, A; Martínez-Carballo, M A

    2015-01-01

    [Oiii]{\\lambda}{\\lambda}4959,5007 "blue outliers" -- that are suggestive of outflows in the narrow line region of quasars -- appear to be much more common at intermediate z (high luminosity) than at low z. About 40% of quasars in a Hamburg ESO intermediate-z sample of 52 sources qualify as blue outliers (i.e., quasars with [OIII] {\\lambda}{\\lambda}4959,5007 lines showing large systematic blueshifts with respect to rest frame). We discuss major findings on what has become an intriguing field in active galactic nuclei research and stress the relevance of blue outliers to feedback and host galaxy evolution.

  13. Task Switching in a Hierarchical Task Structure: Evidence for the Fragility of the Task Repetition Benefit

    Science.gov (United States)

    Lien, Mei-Ching; Ruthruff, Eric

    2004-01-01

    This study examined how task switching is affected by hierarchical task organization. Traditional task-switching studies, which use a constant temporal and spatial distance between each task element (defined as a stimulus requiring a response), promote a flat task structure. Using this approach, Experiment 1 revealed a large switch cost of 238 ms.…

  14. Magnetoimpedance studies on urine treated Co{sub 66}Ni{sub 7}Si{sub 7}B{sub 20} ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Kotagiri, Ganesh [Advanced Magnetic Materials Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Markandeyulu, G., E-mail: mark@iitm.ac.in [Advanced Magnetic Materials Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Doble, Mukesh; Nandakumar, V. [Department of Biotechnology, Indian Institute of Technology Madras, Chennai 600036 (India)

    2015-11-15

    Magnetoimpedance (MI) response of Co{sub 66}Ni{sub 7}Si{sub 7}B{sub 20} ribbons treated with artificial urine with protein bovine serum albumin (BSA), artificial urine without protein BSA and healthy male urine was studied as a function of time of incubation. The maximum MI [(MI){sub m}] values of the ribbons treated with artificial urine without protein (RTAU) after 3 h, 6 h, 12 h and 24 h of incubation are 30% (at 4 MHz), 15% (at 5 MHz), 14% (at 10 MHz) and 8% (at 13 MHz) respectively. On the other hand, the respective (MI){sub m} values of the ribbons treated with artificial urine with protein (RTAUP) are 33% (at 4 MHz), 25% (at 5 MHz), 20% (at 8 MHz) and 15% (12 MHz). However (MI){sub m} values of the ribbons treated with healthy male urine (RTHMU) after 4 h, 5 h, 10 h and 15 h of incubation are 71% (at 3 MHz), 57% (at 3 MHz), 25% (at 6 MHz) and 25% (at 5 MHz), respectively. The saturation magnetization (M{sub s}) values of RTAU after 3 h, 6 h, 12 h and 24 h of incubation are 71 emu/g, 65 emu/g, 63 emu/g and 60 emu/g respectively whereas, the respective M{sub s} values of RTAUP are 73 emu/g, 69 emu/g, 67 emu/g and 64 emu/g. The M{sub s} values of RTHMU after 4 h, 5 h, 10 h and 15 h of incubation are 96 emu/g, 90 emu/g, 75 emu/g and 75 emu/g respectively. The decrease in M{sub s} and (MI){sub m} values in RTAU and RTAUP compared to as-quenched ribbon is related to the amounts of various elements etched out from the ribbons and increased surface roughness. The M{sub s} and (MI){sub m} values of RTHMU are seen to have increased after 4 h and 5 h of incubation, due to strain relaxation through removal of strain developed during rapid quenching of the ribbons. On the other hand, the M{sub s} and (MI){sub m} values of RTHMU after 10 h and 15 h have decreased due to deterioration of the surface of the ribbons and thus, increase in magnetic (surface) anisotropy. The decrease in (MI){sub m} and M{sub S} of RTAU with the time of incubation are more rapid compared to that

  15. Ribbon regulates morphogenesis of the Drosophila embryonic salivary gland through transcriptional activation and repression.

    Science.gov (United States)

    Loganathan, Rajprasad; Lee, Joslynn S; Wells, Michael B; Grevengoed, Elizabeth; Slattery, Matthew; Andrew, Deborah J

    2016-01-01

    Transcription factors affect spatiotemporal patterns of gene expression often regulating multiple aspects of tissue morphogenesis, including cell-type specification, cell proliferation, cell death, cell polarity, cell shape, cell arrangement and cell migration. In this work, we describe a distinct role for Ribbon (Rib) in controlling cell shape/volume increases during elongation of the Drosophila salivary gland (SG). Notably, the morphogenetic changes in rib mutants occurred without effects on general SG cell attributes such as specification, proliferation and apoptosis. Moreover, the changes in cell shape/volume in rib mutants occurred without compromising epithelial-specific morphological attributes such as apicobasal polarity and junctional integrity. To identify the genes regulated by Rib, we performed ChIP-seq analysis in embryos driving expression of GFP-tagged Rib specifically in the SGs. To learn if the Rib binding sites identified in the ChIP-seq analysis were linked to changes in gene expression, we performed microarray analysis comparing RNA samples from age-matched wild-type and rib null embryos. From the superposed ChIP-seq and microarray gene expression data, we identified 60 genomic sites bound by Rib likely to regulate SG-specific gene expression. We confirmed several of the identified Rib targets by qRT-pCR and/or in situ hybridization. Our results indicate that Rib regulates cell growth and tissue shape in the Drosophila salivary gland via a diverse array of targets through both transcriptional activation and repression. Furthermore, our results suggest that autoregulation of rib expression may be a key component of the SG morphogenetic gene network.

  16. Elementary Theorems Regarding Blue Isocurvature Perturbations

    CERN Document Server

    Chung, Daniel J H

    2015-01-01

    Blue CDM-photon isocurvature perturbations are attractive in terms of observability and may be typical from the perspective of generic mass relations in supergravity. We present and apply three theorems useful for blue isocurvature perturbations arising from linear spectator scalar fields. In the process, we give a more precise formula for the blue spectrum associated with the work of 0904.3800, which can in a parametric corner give a factor of O(10) correction. We explain how a conserved current associated with Peccei-Quinn symmetry plays a crucial role and explicitly plot several example spectra including the breaks in the spectra. We also resolve a little puzzle arising from a naive multiplication of isocurvature expression that sheds light on the gravitational imprint of the adiabatic perturbations on the fields responsible for blue isocurvature fluctuations.

  17. Properties of blue-stained wood

    Directory of Open Access Journals (Sweden)

    Miha Humar

    2008-07-01

    Full Text Available Discoloration of wood is frequently caused by blue-stain fungi. Among them Aureobasidium pullulans and Sclerophoma pithyophila are reported as the most important staining organism. In previous researches, it was generally considered that blue-stain fungi do not influence mechanical properties. However, there were some opposite results published as well. In order to elucidate this issue, specimens made of Scots pine (Pinus sylvestris sapwood were exposed to two blue stain fungi A. pullulans and S. pithyophila for periods between two and eight weeks. FTIR, weight, colour and non-destructive modulus of elasticity measurements were performed before and after exposure. The results showed that blue stain fungi, besides considerable discoloration, do not cause any significant damage to wood. Surprisingly the non-destructive MoE analysis showed that modulus of elasticity even slightly increase after fungal exposure.

  18. Afghanistan: Green-on-Blue Attacks

    Science.gov (United States)

    2013-05-02

    Afghanistan, December 2012, p 35 15 Yousafzai, Sami and Moreau , Ron, http://www.thedailybeast.com/newsweek/2012/08/26/ afghanistan-green-on-blue-killings...spike-insider-attacks- stress-ramadan-fasting, 24 August 2012 37 Yousafzai, Sami and Moreau , Ron, http://www.thedailybeast.com/newsweek/2012/08/26...afghanistan-green-on-blue-killings- explained.html, Afghanistan: ‘Green on Blue’ Killings Explained, 27 August 2012 38 Yousafzai, Sami and Moreau , Ron

  19. A Smart Polymer Composite Based on a NiTi Ribbon and a Magnetic Hybrid Material for Actuators with Multiphysic Transduction

    Directory of Open Access Journals (Sweden)

    Beatriz López-Walle

    2015-12-01

    Full Text Available A smart composite material constituted of a magnetic hybrid film and a NiTi shape memory alloy (SMA ribbon was obtained and characterized. The magnetic hybrid film was joined to the NiTi ribbon in order to combine the properties of both materials. This new composite material combines magnetic properties of the hybrid film, (Fe2O3-CMC/(polyvinyl butyral, and the shape memory properties of the NiTi ribbon, which has a chemical composition of Ti-50.13 at. % Ni. This smart composite material has a mass of 18.3% NiTi ribbon and 81.7% magnetic hybrid film. Results obtained by DSC show that the smart composite material presents a small delay of transformation during warming and cooling because the magnetic hybrid film acts like a thermal insulator. Thermomechanical results indicate that the hybrid material also acts as a mechanical reinforcement, since it is observed that the Stress-Assisted Two-Way Memory Effect (SATWME of the smart composite is lower than the SATWME of the SMA ribbon. The density current values of phase transformations were clearly identified with a thermomechanical apparatus developed in our laboratory. Finally, displacements of the smart composite material in cantilever configuration are obtained by applying an external magnetic field. All these results demonstrate that the smart composite material can be activated by temperature, electrical current, stress, and/or magnetic field, offering good expectations for actuating applications with multiphysic transduction.

  20. Reliability of novel postural sway task test

    Directory of Open Access Journals (Sweden)

    Milan Sedliak

    2013-07-01

    Full Text Available The purpose of this study was to examine the reliability of parameters obtained from a novel postural sway task test based on body movements controlled by visual feedback. Fifty-nine volunteers were divided into two groups. The first group consisted of young (n = 32, 16 females and 16 males, age: 25.2 ± 3.4 years and the second group of elderly individuals (n = 27, 17 females and 10 males, age: 75.7 ± 6.9 years. Participants stood in parallel on a computer based stabilographic platform with the feet approximately a shoulder width apart, the toes slightly pointing outwards, the hands placed on the hips. The computer screen was placed approximately 1.5 meter from the platform at a height of subjects’ eyes. An instantaneous visual feedback of participant’s centre of pressure (COP was given in a form of a blue cross visible on the screen. Participants were instructed to keep the blue cross driven by movements of their hips as close as possible to a predefined curve flowing on the screen. Out of the 6 parameters studied, only the average distance of COP from the curve line and the sum of the COP crossings through the curve line showed high reliability. Correlation between these two highly reliable parameters was -0.89. There was also a statistical difference (p<0.001 between young and elderly in both the average distance of COP from the curve line and the sum of the COP crossings through the curve. To conclude, the novel postural sway task provides a simple tool with relatively low time burden needed for testing. The suggested output parameters measured are highly reliable and easy to interpret.

  1. Algebra task & drill sheets

    CERN Document Server

    Reed, Nat

    2011-01-01

    For grades 3-5, our State Standards-based combined resource meets the algebraic concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are opportunities for problem-solving, patterning, algebraic graphing, equations and determining averages. The combined task & drill sheets

  2. Algebra task & drill sheets

    CERN Document Server

    Reed, Nat

    2011-01-01

    For grades 6-8, our State Standards-based combined resource meets the algebraic concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are opportunities for problem-solving, patterning, algebraic graphing, equations and determining averages. The combined task & drill sheets

  3. Fe基合金薄带的ALDGMI效应%LDGMI effect on amorphous Fe-based alloy ribbons

    Institute of Scientific and Technical Information of China (English)

    张建强; 卢振华

    2012-01-01

    采用单辊快淬法制备的Fe648Co7.2Nb4Si4.8B19.2非晶合金薄带(Fe基合金薄带),在潮湿的大气环境中进行直流焦耳热退火,利用阻抗仪检测了Fe基合金薄带的纵向驱动巨磁阻抗(LDGMI)效应,研究了驱动频率f与LDGMI效应之间的关系,发现存在临界频率fc =80MHz,且当f<fc时LDGMI曲线呈对称性;当f>fc时出现非对称纵向驱动巨磁阻抗效应(ALDGMI).分析认为,出现ALDGMI效应的原因可能是由于薄带表面氧化层与中心非晶软磁层之间的磁交换耦合作用所致.%Amorphous Fe64.8Co7.2Nb4Si4,8Big.2 alloy ribbons(Fe-based alloy ribbons) are prepared by single roller melt-spinning technique. The longitudinal driven gaint magneto-impedance (LDGMI) effect of the Fe-based alloy ribbons which annealed by Joule-heating in the atmosphere of humid air have been investigated by impedance-analyzer. The relationship between ac driven frequencies / and LDGMI effect is discussed and it is proved that has a critical frequency (fc = 80 MHz), the symmetric GMI behavior appears in frequency region(f- fc). The analysis shows that the AGMI effect may be responsible for the magnetic exchange coupling between surface oxide layer and inner amorphous layer.

  4. Current status of self-organized epitaxial graphene ribbons on the C face of 6H-SiC substrates

    Energy Technology Data Exchange (ETDEWEB)

    Camara, Nicolas; Caboni, Alessandra; Godignon, Philippe [IMB-CNM-CSIC, Campus UAB 08193-Bellaterra, Barcelona (Spain); Tiberj, Antoine; Jouault, Benoit; Jabakhanji, Bilal; Camassel, Jean [GES, UMR-CNRS 5650, Universite Montpellier 2, 34095-Montpellier cedex 5 (France); Mestres, Narcis [ICMAB-CSIC, Campus UAB 08193- Bellaterra, Barcelona (Spain)

    2010-09-22

    The current status of long, self-organized, epitaxial graphene ribbons grown on the (0 0 0 -1) face of 6H-SiC substrates is reviewed. First, starting from the early stage of growth it is shown that on the C face of 6H-SiC substrates the sublimation process is not homogeneous. Most of the time it starts from defective sites, dislocations or point defects, that define nearly circular flakes surrounded by bare SiC. These flakes have a volcano-like shape with a graphite chimney at the centre, where the original defect was located. At higher temperatures a complete conversion occurs, which is not yet homogeneous on the whole sample. This growth process can be modified by covering the sample with a graphite cap. It changes the physics of the surface reconstruction during the Si-sublimation process and, on the C face, makes more efficient the reconstruction of few selected terraces with respect to the others. The net result is the formation of strongly step-bunched areas with, in between, long and large reconstructed terraces covered by graphitic material. Despite the low intrinsic optical absorption of a few graphene layers on SiC, micro-transmission experiments, complemented by micro-Raman spectroscopy, demonstrate that most of this graphitic coverage is made of one or two homogeneous graphene layers. We show also that most of the thermal stress between the graphene layer and the 6H-SiC substrate is relaxed by pleats or wrinkles which are clearly visible on the AFM images. Finally, the results of transport experiments performed on the graphitic ribbons reveal the p-type character of the ribbons.

  5. Coupling-governed metamorphoses of the integrable nonlinear Schrödinger system on a triangular-lattice ribbon

    Energy Technology Data Exchange (ETDEWEB)

    Vakhnenko, Oleksiy O., E-mail: vakhnenko@bitp.kiev.ua

    2016-05-27

    Highlights: • The integrable nonlinear Schrödinger system on a triangular-lattice ribbon is inclined to metamorphoses. • The system under study is capable to incorporate the effect of external linear potential. • The system criticality against the background parameter reduces the number of independent field variables. • At critical point the system Poisson structure becomes degenerate. • The effect of criticality is elucidated by the system one-soliton solution. - Abstract: The variativity of governing coupling parameters in the integrable nonlinear Schrödinger system on a triangular-lattice ribbon is shown to ensure the important qualitative rearrangements in the system dynamics. There are at least the two types of system crucial modifications stipulated by the two types of governing parameters. Thus the longitudinal coupling parameters regulated mainly by the background values of concomitant field variables are responsible for the bifurcation of primary integrable nonlinear system into the integrable nonlinear system of Ablowitz–Ladik type. As a consequence in a critical point the number of independent field variables is reduced by a half and the system Poisson structure turns out to be degenerate. On the other hand the transverse coupling parameters regulated basically by the choice of their a priori arbitrary dependencies on time are capable to incorporate the effect of external linear potential. As a consequence the primary integrable nonlinear system with appropriately adjusted parametrical driving becomes isomorphic to the system modeling the Bloch oscillations of charged nonlinear carriers in an electrically biased ribbon of triangular lattice. The multi-component structure of basic integrable system alongside with the attractive character of system nonlinearities has predetermined the logic of whole consideration.

  6. Frequency dependence of the magnetostrictive phenomenon in Metglas® 2605SA1 ribbon: A minor-loop case

    Directory of Open Access Journals (Sweden)

    S. U. Jen

    2014-12-01

    Full Text Available Frequency dependence of magnetostrictive phenomenon of as-cast 2605SA1 ribbon was studied. We applied a sinusoidal sweeping field (H, with a fixed frequency (f, along length (L of the ribbon, and simultaneously recorded the longitudinal magnetostriction (λ∥ and the transverse magnetostriction (λ⊥ as a function of time (t, respectively. f was varied from 0.07 to 122 Hz. In the low-f case (f =0.07 Hz, we observed the frequency-doubling (FD feature in λ∥(t and λ⊥(t curves; i.e., only even harmonic magnetostrictive signals showed up. In the high-f case (f = 122 Hz, we observed the no-frequency-doubling (NFD feature; i.e., both odd and even harmonic magnetostrictive signals showed up. A theory, based on the balance among various torques acting on magnetization, is developed to explain the f dependence of the magnetostriction phenomenon observed. From this theory, we conclude that only when the reflection symmetry of the system is reserved, i.e., when the equivalent easy axis (EEA is perpendicular to L, will λ∥(t and λ⊥(t have the true-frequency-doubling (TFD feature. However, for the as-cast 2605SA1 ribbon, EEA is not perpendicular to L. Thus, strictly speaking, we should observe the NFD feature only. Nevertheless, in the low-f limit, we can show that the FD feature is somewhat allowed under the condition, b/α being close to 1, where b and α are the two parameters used in the theory. From experimental data, this condition is met for as-cast 2605SA1. To make a distinction from TFD, this low-f feature is called close-frequency-doubling (CFD in this paper. In general, the theory explains all the experimental results fairly well.

  7. Terahertz resonances due to edge magnetoplasmons in a wide armchair graphene ribbon with a weak superlattice potential

    Directory of Open Access Journals (Sweden)

    O. G. Balev

    2012-12-01

    Full Text Available A strong modulation of the resonance frequencies and the gaps of edge magnetoplamons (EMPs, in the ribbon at the ν = 2 quantum Hall effect regime with a superlattice and a smooth steplike electrostatic lateral potential, due to a modulation of the interedge distance is shown. We obtain that, in a wide range of the interedge distances, within THz region the EMPs show wide frequency gaps and at peculiar frequencies the response of the system should manifest resonances. For the latter frequencies the group velocities are nullified.

  8. Effect of stress on magnetic losses and role of Mn addition in Fe-Si rapidly solidified ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Ferrando, L.; Lebourg, C.; Ferrara, E.; Appino, C.; Fiorillo, F.; Degauque, J. E-mail: degauque@insatlse.insa-tlse.fr; Gauffier, J.L.; Shin, D.W.; Baricco, M

    2000-06-02

    It is shown that bending stresses detrimentally affect magnetic losses in Fe-Si ribbons at all frequencies, to an extent that is minimum at 6.7 wt% Si concentration. A magnetoelastically induced redistribution of the domains among the easy axes is assumed to be the leading cause for the observed extra losses upon bending. Addition of 0.15 wt% Mn, while not affecting the magnetic properties, is shown to improve the mechanical behavior of the relatively brittle low-loss high-Si alloys.

  9. A Daunting Task Still

    Institute of Scientific and Technical Information of China (English)

    ZHANG ZHIPING

    2010-01-01

    @@ Despite steady economic growth for three decades, China is still a developing country facing daunting poverty alleviation tasks. According to the poverty line of 1,196 yuan ($176) per capita net income in a year set in March 2009, the country still has a poverty population of more than 40 million, mainly living in rural areas.

  10. Task 1 quarternary tectonics

    Energy Technology Data Exchange (ETDEWEB)

    Bell, J.W.

    1994-12-31

    Activities on the task of quarternary tectonics for the Yucca Mountain Site investigations are described. Technical topics include: A preliminary reveiw of Bare Mountain Trench; A preliminary detailed lineament map of the Southwestern part of the proposed repository; A discussion on the 1994 Double Spring Flat, Nevada earthquake; and evidence for temporal clustering.

  11. Comparison of Alcian Blue, Trypan Blue, and Toluidine Blue for Visualization of the Primo Vascular System Floating in Lymph Ducts

    Directory of Open Access Journals (Sweden)

    Da-Un Kim

    2015-01-01

    Full Text Available The primo vascular system (PVS, floating in lymph ducts, was too transparent to be observed by using a stereomicroscope. It was only detectable with the aid of staining dyes, for instance, Alcian blue, which was injected into the lymph nodes. Some dyes were absorbed preferentially by the PVS than the lymph wall. It remains a standing problem to know what dyes are absorbed better by the PVS than the lymph walls. Such information would be useful to unravel the biochemical properties of the PVS that are badly in need for obtaining large amount of PVS specimens. In the current work we tried two other familiar dyes which were used in PVS research before. We found that Trypan blue and toluidine blue did not visualize the PVS. Trypan blue was cleared by the natural washing. Toluidine blue did not stain the PVS, but it did leave stained spots in the lymph wall and its surrounding tissues, and it leaked out of the lymph wall to stain surrounding connective tissues. These completely different behaviors of the three dyes were found for the first time in the current work and provide valuable information to elucidate the mechanism through which some special dyes stained the PVS preferentially compared to the lymphatic wall.

  12. Magnetization and demagnetization behaviours of melt-spun Pr12Fe82B6 and Pr8Fe87B5 ribbons

    Institute of Scientific and Technical Information of China (English)

    Du Xiao-Bo; Zhang Hong-Wei; Rong Chuan-Bing; Zhang Jian; Zhang Shao-Ying; Shen Bao-Gen; Yan Yu; Jin Han-Min

    2004-01-01

    Nanocrystalline Prl2Fe82B6 and nanocomposite Pr8Fe87B5 ribbons have been prepared using a melt spinning technique. Recoil loops have been measured at 20, 200 and 300K. Demagnetization curves are analysed by dividing it into reversible and irreversible portions. High recoil loop susceptibility at low applied field and large reversible change in the demagnetization curve have been found in Pr8Fe87B5 ribbons, showing that the reversible behaviours in nanocomposite permanent magnets originate primarily from the magnetically soft phase. The hysteresis in recoil loops found in Pr8Fe87B5 ribbons originates from the soft phase α-Fe that suffers a stress.

  13. Creation of a sharp cube texture in ribbon substrates of Cu-40% Ni- M ( M = Fe, Cr, V) ternary alloys for high-temperature second generation superconductors

    Science.gov (United States)

    Khlebnikova, Yu. V.; Rodionov, D. P.; Gervas'eva, I. V.; Suaridze, T. R.; Egorova, L. Yu.

    2016-11-01

    The structure and the process of texture formation in ribbons made of Cu-Ni- M ( M = Fe, Cr, V) ternary alloys have been studied upon cold rolling deformation to a degree of 99% and subsequent recrystallization annealing. The possibility of obtaining a perfect cube texture in a thin ribbon made of copper-nickel-based ternary alloys with additives of iron, chromium, and vanadium has been shown, which opens the prospects of the use of these alloys as substrates in the technology of production of tapes of high-temperature second-generation superconductors. Optimal annealing regimes have been determined, which make it possible to obtain a perfect biaxial texture close to single-crystalline one with the content of cube-oriented grains {001}±10° more than 99% on the surface of the textured ribbon.

  14. Exchange bias behavior in Ni{sub 50.0}Mn{sub 35.5} In{sub 14.5} ribbons annealed at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, T. [Dept. de Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Sato Turtelli, R.; Groessinger, R. [Institut fur Festkoerperphysik, Technische Universitaet Wien, Wiedner Hauptstr. 8-10, 1040 Vienna (Austria); Sanchez, M.L.; Santos, J.D.; Rosa, W.O.; Prida, V.M. [Dept. de Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Escoda, Ll.; Sunol, J.J. [Campus de Montilivi, Universidad de Girona, edifici PII, Lluis Santalo s/n. 17003 Girona (Spain); Koledov, V. [Kotelnikov Institute of Radio Engineering and Electronics, RAS, Moscow 125009 (Russian Federation); Hernando, B., E-mail: grande@uniovi.es [Dept. de Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain)

    2012-10-15

    Heusler alloy Ni{sub 50.0}Mn{sub 35.5}In{sub 14.5} ribbons were prepared by melt-spinning technique. Several short time annealings were carried out in order to enhance the exchange bias effect in this alloy ribbon. The magnetic transition temperature increases with the annealing, compared to the as-spun sample, however no significant differences in respective Curie temperatures were observed for austenite and martensite phases in such annealed samples. Exchange bias effect is observed at low temperatures for all samples and practically vanishes at 60 K for the as-spun sample, whereas for the annealed ribbons it vanishes at 100 K.

  15. Variations on the "Blue-Bottle" Demonstration Using Food Items That Contain FD&C Blue #1

    Science.gov (United States)

    Staiger, Felicia A.; Peterson, Joshua P.; Campbell, Dean J.

    2015-01-01

    Erioglaucine dye (FD&C Blue #1) can be used instead of methylene blue in the classic "blue-bottle" demonstration. Food items containing FD&C Blue #1 and reducing species such as sugars can therefore be used at the heart of this demonstration, which simply requires the addition of strong base such as sodium hydroxide lye.

  16. 21 CFR 133.184 - Roquefort cheese, sheep's milk blue-mold, and blue-mold cheese from sheep's milk.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Roquefort cheese, sheep's milk blue-mold, and blue-mold cheese from sheep's milk. 133.184 Section 133.184 Food and Drugs FOOD AND DRUG ADMINISTRATION..., sheep's milk blue-mold, and blue-mold cheese from sheep's milk. (a) Description. (1) Roquefort...

  17. "Blue-Collar Blues" uurib töösuhteid uutes oludes / Janar Ala

    Index Scriptorium Estoniae

    Ala, Janar, 1979-

    2009-01-01

    Tööproblemaatikat käsitlev näitus "Blue-Collar Blues" Tallinna Kunstihoones ja Tallinna Kunstihoone galeriis 31. jaanuarini 2010, kuraator Anders Härm. Lähemalt belgia-mehhiko kunstniku Francis Alys'e videost, austria kunstniku Oliver Ressleri ning venetsueela-saksa politoloogi Dario Azzelini videost "Viis tehast. Tööliste kontroll Venezuelas"

  18. 75 FR 65525 - Anthem Blue Cross Blue Shield, Claim Management Services, Inc. Operations, a Division of...

    Science.gov (United States)

    2010-10-25

    ... Management Services, Inc. Operations, a Division of Wellpoint, Inc., Green Bay, Wisconsin (the subject firm... Employment and Training Administration Anthem Blue Cross Blue Shield, Claim Management Services, Inc. Operations, a Division of Wellpoint, Inc., Green Bay, WI; Notice of Negative Determination...

  19. Evaluation of Domain-Specific Collaboration Interfaces for Team Command and Control Tasks

    Science.gov (United States)

    2012-05-01

    Vocal process V Spatial concentrative S 2.2.6. Procedure As mentioned previously, several team roles employed in this experiment were...providing specific strategies for task execution. Following the behavioral training session, each confederate was assigned to a specific team role (blue

  20. Influence of low-temperature nitridation on low-frequency magnetization of Fe82Nb7B10Cu1 nanocrystalline alloy ribbons

    Institute of Scientific and Technical Information of China (English)

    XU Feng; WU Xiao-ling; LI Shan-dong; PENG Kun; CHEN Guang; DU You-wei

    2006-01-01

    The nanocrystalline Fe82Nb7B10Cu1 soft magnetic ribbons were treated with the mixture gas flow of ammonia and hydrogen at 673 K. The influence of the nitridation treatment was studied by the low-frequency permeability spectra. The result shows that this kind of nitridation treatment can improve the soft magnetic properties under some application conditions. The reason for the improvement of the soft magnetic properties by slight nitridation was discussed on the basis of domain wall bulging model. Therefore for the Fe-based nanocrystalline soft magnetic alloy ribbons, the nitridation treatment can be used as an effective and easy method to control the magnetic properties.

  1. BluePyOpt: Leveraging Open Source Software and Cloud Infrastructure to Optimise Model Parameters in Neuroscience

    Science.gov (United States)

    Van Geit, Werner; Gevaert, Michael; Chindemi, Giuseppe; Rössert, Christian; Courcol, Jean-Denis; Muller, Eilif B.; Schürmann, Felix; Segev, Idan; Markram, Henry

    2016-01-01

    At many scales in neuroscience, appropriate mathematical models take the form of complex dynamical systems. Parameterizing such models to conform to the multitude of available experimental constraints is a global non-linear optimisation problem with a complex fitness landscape, requiring numerical techniques to find suitable approximate solutions. Stochastic optimisation approaches, such as evolutionary algorithms, have been shown to be effective, but often the setting up of such optimisations and the choice of a specific search algorithm and its parameters is non-trivial, requiring domain-specific expertise. Here we describe BluePyOpt, a Python package targeted at the broad neuroscience community to simplify this task. BluePyOpt is an extensible framework for data-driven model parameter optimisation that wraps and standardizes several existing open-source tools. It simplifies the task of creating and sharing these optimisations, and the associated techniques and knowledge. This is achieved by abstracting the optimisation and evaluation tasks into various reusable and flexible discrete elements according to established best-practices. Further, BluePyOpt provides methods for setting up both small- and large-scale optimisations on a variety of platforms, ranging from laptops to Linux clusters and cloud-based compute infrastructures. The versatility of the BluePyOpt framework is demonstrated by working through three representative neuroscience specific use cases. PMID:27375471

  2. Amorphous Fe72Cu1V4Si15B8 ribbon as magneto-impedance sensing element

    Directory of Open Access Journals (Sweden)

    Surla Radoslav

    2016-01-01

    Full Text Available Мagneto-impedance (MI effect in the Fe72Cu1V4Si15B8 amorphous ribbon obtained by melt spinning method has been studied. The aim of study was the characterisation of this ribbon in as-cast state in terms of its application as a MI sensor. The experiments on MI elements were performed in the frequency range from 30 kHz to 300 MHz and maximum external magnetic field up to 28.6 kA/m. Maximum observed MI-ratio (ΔZ = Z(0 - Z(Hmax, Hmax = 28.6 kA/m has amounted to ΔZ/Z(Hmax = 173% at a frequency of 20.46 MHz. The MI curve measured up to 20 MHz shows some shoulder indicating the growth of rotational contribution of magnetization that appears above the domain wall relaxation frequency. The MI profile at frequencies higher than 30 MHz, exhibits a clear peak positioned at transverse anisotropy field Hk, suggesting domination of rotation magnetization in transverse permeability. The linearity in the range up to 5 kA/m with sensitivity of about 11 %/kA/m was observed. [Projekat Ministarstva nauke Republike Srbije, br. OI 172057

  3. Effects of Slight Plastic Deformation on Magnetic Properties and Giant Magnetoimpedance of FeCoCrSiB Amorphous Ribbons

    Institute of Scientific and Technical Information of China (English)

    S.O.Volchkov; M.A.Cerdeira; V.V.Gubernatorov; E.I.Duhan; A.P.Potapov; V.A.Lukshina

    2007-01-01

    Slight plastic deformation of 0 to 1% by cold rolling is proposed as a treatment which may modify the responses of magnetoimpedance (MI) sensor with an amorphous ribbon used as a sensitive element. The dependence of the magnetic properties of melt spun Fe3Co67Cr3Si15B12 amorphous ribbons and their MI responses in the initial state and after slight plastic deformation on the value of the deformation were comparatively analysed. The shape of the hysteresis loops shows a clear correlation with the value of the deformation. The variations of the total impedance, the real and the imaginary components, are measured for the current intensity of 1.5mA for the frequency of 10 MHz. Slight plastic deformation affects both real and imaginary components and allows a control of the shape of the MI curves in a small Geld in a range usually used in biomedical applications. The proposed deformation treatments can be useful for the construction of the MI sensitive elements with a new type of the responses.

  4. Unveiling the pentagonal nature of perfectly aligned single-and double-strand Si nano-ribbons on Ag(110)

    Science.gov (United States)

    Cerdá, Jorge I.; Sławińska, Jagoda; Le Lay, Guy; Marele, Antonela C.; Gómez-Rodríguez, José M.; Dávila, María E.

    2016-10-01

    Carbon and silicon pentagonal low-dimensional structures attract a great interest as they may lead to new exotic phenomena such as topologically protected phases or increased spin-orbit effects. However, no pure pentagonal phase has yet been realized for any of them. Here we unveil through extensive density functional theory calculations and scanning tunnelling microscope simulations, confronted to key experimental facts, the hidden pentagonal nature of single- and double-strand chiral Si nano-ribbons perfectly aligned on Ag(110) surfaces whose structure has remained elusive for over a decade. Our study reveals an unprecedented one-dimensional Si atomic arrangement solely comprising almost perfect alternating pentagons residing in the missing row troughs of the reconstructed surface. We additionally characterize the precursor structure of the nano-ribbons, which consists of a Si cluster (nano-dot) occupying a silver di-vacancy in a quasi-hexagonal configuration. The system thus materializes a paradigmatic shift from a silicene-like packing to a pentagonal one.

  5. Silicene Nano-Ribbons: Strong Resistance Towards Oxidation due to sp2 Hybridization of the Si Valence Orbitals

    Science.gov (United States)

    Le Lay, Guy; de Padova, Paola; Quaresima, Claudio; Olivieri, Bruno; Perfetti, Paolo

    2011-03-01

    We have synthesized for the first time silicene, that is, a new silicon allotrope analogous to graphene recently theoretically predicted, in the form of a massively parallel array of quantized zigzag nano-ribbons with a common ``magic'' width of 1.6 nm. They display characteristic linear band dispersions similar to the Dirac cones of graphene, in correspondence with their hexagonal arrangement seen in STM imaging. Here we show, through the angle-dependence of REEL spectra taken at the Si L2 , 3 edge, the typical signatures of 2p --> π * and 2p --> σ * transitions associated with sp 2 hybridization of the Si valence orbitals. We further show through high-resolution synchrotron radiation Si 2p core-level spectroscopy measurements that the afore mentioned silicene grating is very resistant toward oxidation. Typically, the oxygen uptake starts at about 104 higher doses than on the clean Si(111)7x7 surface. Indeed, this striking behavior is directly related to the sp 2 bonding, an additional confirmation of the silicene (i.e., graphene-like) nature of the nano-ribbons.

  6. Unveiling the pentagonal nature of perfectly aligned single-and double-strand Si nano-ribbons on Ag(110)

    Science.gov (United States)

    Cerdá, Jorge I.; Sławińska, Jagoda; Le Lay, Guy; Marele, Antonela C.; Gómez-Rodríguez, José M.; Dávila, María E.

    2016-01-01

    Carbon and silicon pentagonal low-dimensional structures attract a great interest as they may lead to new exotic phenomena such as topologically protected phases or increased spin–orbit effects. However, no pure pentagonal phase has yet been realized for any of them. Here we unveil through extensive density functional theory calculations and scanning tunnelling microscope simulations, confronted to key experimental facts, the hidden pentagonal nature of single- and double-strand chiral Si nano-ribbons perfectly aligned on Ag(110) surfaces whose structure has remained elusive for over a decade. Our study reveals an unprecedented one-dimensional Si atomic arrangement solely comprising almost perfect alternating pentagons residing in the missing row troughs of the reconstructed surface. We additionally characterize the precursor structure of the nano-ribbons, which consists of a Si cluster (nano-dot) occupying a silver di-vacancy in a quasi-hexagonal configuration. The system thus materializes a paradigmatic shift from a silicene-like packing to a pentagonal one. PMID:27708263

  7. Weibull modulus of hardness, bend strength, and tensile strength of Ni−Ta−Co−X metallic glass ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Neilson, Henry J., E-mail: hjn2@case.edu [Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH (United States); Petersen, Alex S.; Cheung, Andrew M.; Poon, S. Joseph; Shiflet, Gary J. [University of Virginia, 395 McCormick Road, P.O. Box 400745, Charlottesville, VA 22904 (United States); Widom, Mike [Carnegie Mellon University, 5000 Forbes Avenue, Wean Hall 3325, Pittsburgh, PA 15213 (United States); Lewandowski, John J. [Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH (United States)

    2015-05-14

    In this study, the variations in mechanical properties of Ni−Co−Ta-based metallic glasses have been analyzed. Three different chemistries of metallic glass ribbons were analyzed: Ni{sub 45}Ta{sub 35}Co{sub 20}, Ni{sub 40}Ta{sub 35}Co{sub 20}Nb{sub 5}, and Ni{sub 30}Ta{sub 35}Co{sub 30}Nb{sub 5}. These alloys possess very high density (approximately 12.5 g/cm{sup 3}) and very high strength (e.g. >3 GPa). Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) were used to characterize the amorphicity of the ribbons. Mechanical properties were measured via a combination of Vickers hardness, bending strength, and tensile strength for each chemistry. At least 50 tests were conducted for each chemistry and each test technique in order to quantify the variability of properties using both 2- and 3-parameter Weibull statistics. The variability in properties and their source(s) were compared to that of other engineering materials, while the nature of deformation via shear bands as well as fracture surface features have been determined using scanning electron microscopy (SEM). Toughness, the role of defects, and volume effects are also discussed.

  8. Pain Management Task Force

    Science.gov (United States)

    2010-05-01

    Additionally, the Task Force consulted with the Samueli Institute, a non-profit research organization that supports the scientific investigation of healing...and its role in medicine and health care. The Samueli Institute has been working on several research projects related to military and Veterans’ pain... Samueli communication). The CAM subgroup of the TF studied the issues surrounding credentialing and licensing of CAM providers. The tiered

  9. Features or tasks?

    DEFF Research Database (Denmark)

    Heilesen, Simon

    In this paper for the Workshop on Human-computer interaction and e-learning, NordiCHI 2002, the author argues that in developing innovative E-learning systems, especially if constructivist pedagogy is to be applied, it will be useful to model the user interface on the often complex tasks...... that the user has to perform rather than just focusing on technical features (and adapting system use to them)....

  10. Chinese Jingdezhen blue and white imperial porcelain

    Institute of Scientific and Technical Information of China (English)

    WU; Juan; LI; Jiazhi; DENG; Zequn; WANG; Changsui

    2004-01-01

    Jingdezhen blue and white imperial porcelain specimens from the Yuan, Ming and Qing dynasties have been systematically analyzed using a nondestructive test method--?energy dispersive X-ray fluorescence analysis (EDXRF). The derived data of major and trace element compositions have been treated by correspondence analysis. The variation laws of the composition patterns for Jingdezhen blue and white imperial porcelain in different historical periods owing to the change in raw materials, recipe and technology have been discussed, and a time model related to variation of element composition has been preliminarily established, It would be helpful for scientific dating of Jingdezhen blue and white imperial porcelain, and even for the studies on the whole field of identification of ancient ceramics.

  11. Bump in the blue axion isocurvature spectrum

    Science.gov (United States)

    Chung, Daniel J. H.; Upadhye, Amol

    2017-01-01

    Blue axion isocurvature perturbations are both theoretically well motivated and interesting from a detectability perspective. These power spectra generically have a break from the blue region to a flat region. Previous investigations of the power spectra were analytic, which left a gap in the predicted spectrum in the break region due to the nonapplicability of the used analytic techniques. We therefore compute the isocurvature spectrum numerically for an explicit supersymmetric axion model. We find a bump that enhances the isocurvature signal for this class of scenarios. A fitting function of three parameters is constructed that fits the spectrum well for the particular axion model we study. This fitting function should be useful for blue isocurvature signal hunting in data and making experimental sensitivity forecasts.

  12. A Stable Blue Organic Electroluminescent Material

    Institute of Scientific and Technical Information of China (English)

    郑新友; 吴有智; 等

    2002-01-01

    In order to compare two kinds of blue electroluminescent materials,we have investigated two kinds of blue OLEDs with the similar structure ITO/CuPc/NPB/JBEM:perylene/Alq/Mg:Ag[device(J)] and ITO/CuPc/NPB/DPVBi:perylene/Alq/Mg:Ag[device(D)].The difference of luminance and efficiency was not obvious for the two devices,However,there was remarkable difference for their lifetime.The device(J) achieved longer half lifetime of 1035h at initial luminance of 100 cd/m2,and that of device(D) was only255h,According to their energy level diagrams,the differentce of their stability may originate from different host materials in the two devices.It may be attributed to the better thermal stability of JBEM molecues than that of DPVBi.It is shown that JBEM may be a promising blue organic electroluminescent material with great stability.

  13. Gap Task Force

    CERN Document Server

    Lissuaer, D

    One of the more congested areas in the ATLAS detector is the GAP region (the area between the Barrel Calorimeter and the End Cap calorimeter) where Inner Detector services, LAr Services and some Tile services all must co-habitat in a very limited area. It has been clear for some time that the space in the GAP region is not sufficient to accommodate all that is needed. In the last few month additional problems of routing all the services to Z=0 have been encountered due to the very limited space between the Tile Calorimeter and the first layer of Muon chambers. The Technical Management Board (TMB) and the Executive Board (EB) decided in the middle of March to establish a Task Force to look at this problem and come up with a solution within well-specified guidelines. The task force consisted of experts from the ID, Muon, Liquid Argon and Tile systems in addition to experts from the Technical Coordination team and the Physics coordinator. The task force held many meetings and in general there were some very l...

  14. Mobile Thread Task Manager

    Science.gov (United States)

    Clement, Bradley J.; Estlin, Tara A.; Bornstein, Benjamin J.

    2013-01-01

    The Mobile Thread Task Manager (MTTM) is being applied to parallelizing existing flight software to understand the benefits and to develop new techniques and architectural concepts for adapting software to multicore architectures. It allocates and load-balances tasks for a group of threads that migrate across processors to improve cache performance. In order to balance-load across threads, the MTTM augments a basic map-reduce strategy to draw jobs from a global queue. In a multicore processor, memory may be "homed" to the cache of a specific processor and must be accessed from that processor. The MTTB architecture wraps access to data with thread management to move threads to the home processor for that data so that the computation follows the data in an attempt to avoid L2 cache misses. Cache homing is also handled by a memory manager that translates identifiers to processor IDs where the data will be homed (according to rules defined by the user). The user can also specify the number of threads and processors separately, which is important for tuning performance for different patterns of computation and memory access. MTTM efficiently processes tasks in parallel on a multiprocessor computer. It also provides an interface to make it easier to adapt existing software to a multiprocessor environment.

  15. Blue light inhibits proliferation of melanoma cells

    Science.gov (United States)

    Becker, Anja; Distler, Elisabeth; Klapczynski, Anna; Arpino, Fabiola; Kuch, Natalia; Simon-Keller, Katja; Sticht, Carsten; van Abeelen, Frank A.; Gretz, Norbert; Oversluizen, Gerrit

    2016-03-01

    Photobiomodulation with blue light is used for several treatment paradigms such as neonatal jaundice, psoriasis and back pain. However, little is known about possible side effects concerning melanoma cells in the skin. The aim of this study was to assess the safety of blue LED irradiation with respect to proliferation of melanoma cells. For that purpose we used the human malignant melanoma cell line SK-MEL28. Cell proliferation was decreased in blue light irradiated cells where the effect size depended on light irradiation dosage. Furthermore, with a repeated irradiation of the melanoma cells on two consecutive days the effect could be intensified. Fluorescence-activated cell sorting with Annexin V and Propidium iodide labeling did not show a higher number of dead cells after blue light irradiation compared to non-irradiated cells. Gene expression analysis revealed down-regulated genes in pathways connected to anti-inflammatory response, like B cell signaling and phagosome. Most prominent pathways with up-regulation of genes were cytochrome P450, steroid hormone biosynthesis. Furthermore, even though cells showed a decrease in proliferation, genes connected to the cell cycle were up-regulated after 24h. This result is concordant with XTT test 48h after irradiation, where irradiated cells showed the same proliferation as the no light negative control. In summary, proliferation of melanoma cells can be decreased using blue light irradiation. Nevertheless, the gene expression analysis has to be further evaluated and more studies, such as in-vivo experiments, are warranted to further assess the safety of blue light treatment.

  16. Change in NO2 reveals Parade Blue is cleaner than APEC Blue

    Science.gov (United States)

    Liu, Haoran; Liu, Cheng; Xie, Zhouqing; Xie, Pinhua; Xing, Chengzhi; Xu, Jin; Liu, Jianguo

    2016-04-01

    The spectacular Parade Blue (blue sky), and APEC Blue (blue sky) were renowned worldwide caused by the limiting discharge policy of the Chinese government. For evaluating the reduction of these two events, we analyzed the variation of NO2 columns Beijing by looking at a long-term monitoring using Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) and the Ozone Monitoring Instrument (OMI) satellite observations from August 2014 to November 2015, covering Grand Military Parade (GMP, September 2015) and APEC (November 2014) period. We found that the NO2 columns abruptly decreased both GMP and APEC. However, change in the MAX-DOAS and the OMI NO2 during GMP was larger than during APEC via comparison with the same period in 2014, indicating Parade Blue is cleaner than APEC Blue. The spatial distribution of NO2 and backward trajectories together with meterological parameters suggested that GMP Blue may be due to the regional significant decreasing discharge in peripheral cities. No weekend effect during GMP further confirmed the role of controlling discharge. This study provides direct evidence that it is possible to clean air in China.

  17. DeepBlue epigenomic data server: programmatic data retrieval and analysis of epigenome region sets.

    Science.gov (United States)

    Albrecht, Felipe; List, Markus; Bock, Christoph; Lengauer, Thomas

    2016-07-01

    Large amounts of epigenomic data are generated under the umbrella of the International Human Epigenome Consortium, which aims to establish 1000 reference epigenomes within the next few years. These data have the potential to unravel the complexity of epigenomic regulation. However, their effective use is hindered by the lack of flexible and easy-to-use methods for data retrieval. Extracting region sets of interest is a cumbersome task that involves several manual steps: identifying the relevant experiments, downloading the corresponding data files and filtering the region sets of interest. Here we present the DeepBlue Epigenomic Data Server, which streamlines epigenomic data analysis as well as software development. DeepBlue provides a comprehensive programmatic interface for finding, selecting, filtering, summarizing and downloading region sets. It contains data from four major epigenome projects, namely ENCODE, ROADMAP, BLUEPRINT and DEEP. DeepBlue comes with a user manual, examples and a well-documented application programming interface (API). The latter is accessed via the XML-RPC protocol supported by many programming languages. To demonstrate usage of the API and to enable convenient data retrieval for non-programmers, we offer an optional web interface. DeepBlue can be openly accessed at http://deepblue.mpi-inf.mpg.de.

  18. Fatigue resistance, debonding force, and failure type of fiber-reinforced composite, polyethylene ribbon-reinforced, and braided stainless steel wire lingual retainers in vitro

    NARCIS (Netherlands)

    Foek, Dave Lie Sam; Yetkiner, Enver; Ozcan, Mutlu

    2013-01-01

    Objective: To analyze the fatigue resistance, debonding force, and failure type of fiber-reinforced composite, polyethylene ribbon-reinforced, and braided stainless steel wire lingual retainers in vitro. Methods: Roots of human mandibular central incisors were covered with silicone, mimicking the pe

  19. Investigation of Bending Trainings, Transformation Temperatures, and Stability of Two-Way Shape Memory Effect in NiTi-Based Ribbons

    Science.gov (United States)

    Mehrabi, K.; Bruncko, M.; Kneissl, A. C.

    2013-05-01

    This paper discusses the application of rapid solidification by the melt-spinning method for the preparation of thin NiTi-based ribbons. Generally, the application of rapid solidification via melt-spinning can change the microstructure, improving the ductility and shape memory characteristics and lead to small-dimensioned samples. Several thousand thermal cycles were performed on the trained ribbons using bending deformation procedure, continuously observing the changes in the shape memory and transformation behaviors. These changes are due to the appearance of an intermediate phase which was stabilized probably by the accumulation of defects introduced by thermomechanical training. The influence of training and thermal cycling on characteristics of ribbons was studied by x-ray diffraction and transmission electron microscopy and differential scanning calorimetry. The results displayed that bending training methods were useful in developing a two-way shape memory effect (TWSME). All samples show a shape memory effect immediately after processing without further heat treatment. The addition of copper in NiTi alloys was effective to narrow the transformation hysteresis. The W addition has improved the stability of the TWSME and mechanical properties. The TWSME of ribbons and its stability are well suited for important applications such as microsensors and microactuators.

  20. Microstructure refinement and magnetic properties enhancement of nanocrystalline Nd12.3Fe81.7B6.0 ribbons by addition of Zr

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Effects of Zr addition and annealing treatment on the formation, microstructure and magnetic properties of Nd12.3Fe81.7?xZrxB6.0 (x=0―3.0) ribbons melt-spun and annealed have been systematically investigated by means of vibrating sample magnetometer (VSM), differential scanning calorimeter (DSC), X-ray diffraction (XRD), and high resolution scanning electron microscopy (HRSEM). Phase analysis reveals that Nd2Fe14B is single-phase material. It has been found that the intrinsic coercivity Hci of the optimally processed Nd12.3Fe81.7?xZrxB6.0 ribbons increases monotonically from 751.7 kA/m for x=0 to 1005.3 kA/m for x=3.0. The remanence polarization Jr and maximum energy product (BH)max increase first with Zr addition, then slightly decrease with further increasing Zr content. Optimum magnetic properties with Jr=1.041 T, Hci=887.5 kA/m and (BH)max=175.2 kJ/m3 have been achieved for the ribbons with x=1.5. The significant improvement of magnetic properties originates from the finer grains of the ribbons by introducing Zr.

  1. WO3 nano-ribbons: their phase transformation from tungstite (WO3·H2O) to tungsten oxide (WO3)

    DEFF Research Database (Denmark)

    Ahmadi, Majid; Sahoo, Satyaprakash; Younesi, Reza

    2014-01-01

    Tungsten oxide (WO3) nano-ribbons (NRs) were obtained by annealing tungstite (WO3·H2O) NRs. The latter was synthesized below room temperature using a simple, environmentally benign, and low cost aging treatment of precursors made by adding hydrochloric acid to diluted sodium tungstate solutions (Na...

  2. Evidence of microstructures and fluid inclusions for the origin of polycrystalline quartz ribbons in high-grade metamorphic rocks in Daqingshan region

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Polycrystalline quartz ribbons in high-grade metamorphic rocks from the Daqingshan region, are typi- cal microfabrics of, and provide information for, deep crust deformation and metamorphism. The quartz ribbons have straight boundaries and extend stably along gneissosity. They truncate other mineral grains in the rocks and may contain inclusions of such minerals that are lens-shaped and oriented. They frequently end into branching termination. Analysis fluid inclusions in polycrystalline quartz rib- bons reveal that the complex types of fluid inclusions are inhomogeneously distributed. They are ob- viously different from inclusions captured at granulite facies, in both fluid compositions and T-P esti- mations. Based on microfabric and fluid inclusion analysis, the polycrystalline quartz ribbons are suggested to be formed by SO2-rich fluids filling micro-fractures that are parallel to early gneissosity. The SO2 composition is derived from the deformed host rocks. The fluid phase has significant effects on the rheological characteristics, fracturing of rocks, and formation of quartz ribbons.

  3. Quarternary tectonics, Task 1

    Energy Technology Data Exchange (ETDEWEB)

    Bell, J.W.

    1993-09-30

    Activities conducted for the evaluation of the geology and seismotectonics stability of Yucca Mountain as a potential site for the underground disposal of high-level radioactive wastes continued. Tasks concerned with quaternary tectonics include: scheduling of photography of Little Skull Mountain area; the collection and dating of rock varnish samples from the 1932 Cedar Mountain earthquake area for carbon 14 AMS and cation-ratio analysis; collection of samples for thermoluminescence dating from the 1932 Cedar Mountain earthquake area; mapping of the northern area of Crater Flat; and surveying of the May 17, 1993 Eureka the Valley earthquake area.

  4. Calorimetry Task Force Report

    CERN Document Server

    Abdullin, Salavat; Banerjee, Sunanda; Beauceron, Stephanie; Beaudette, Florian; Bhatti, Anwar; Chlebana, Frank; Cossutti, Fabio; Hirschauer, James; Ivanchenko, V; Jang, Dong Wook; Jun, Soon Yung; Kunori, Shuichi; Kroeger, Rob; Liu, Yanwen; Moeller, Anthony; Paulini, Manfred; Piperov, Stefan; Rahmat, Rahmat; Rovelli, Chiara; Safronov, Grigory; Sharma, Seema; Spiropulu, Maria; Yetkin, Taylan

    2010-01-01

    In this note we summarize the progress made by the calorimeter simulation task force (CaloTF) over the past year. The CaloTF was established in February 2008 in order to understand and reconcile the discrepancies observed between the CMS calorimetry simulation and test beam data recorded during 2004 and 2006. The simulation has been significantly improved by using a newer version of Geant4 and an improved physics list for the full CMS detector simulation. Simulation times have been reduced by introducing flexible parameterizations to describe showering in the calorimeter (using a Gflash-like approach) which have been tuned to the test beam data.

  5. Modeling of spectral characteristics of blue LEDs

    DEFF Research Database (Denmark)

    Thorseth, Anders

    2010-01-01

    are expected to vary with current and junction temperature. Commercial high power blue LEDs were measured with respect to spectral distribution and chromaticity and the result was compared with the model predictions. We have found that the models predict significantly different results with respect...

  6. Blue whales respond to anthropogenic noise.

    Directory of Open Access Journals (Sweden)

    Mariana L Melcón

    Full Text Available Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to stop calling at any time of day, showing no diel pattern in their sensitivity to sonar. Conversely, the likelihood of whales emitting calls increased when ship sounds were nearby. Whales did not show a differential response to ship noise as a function of the time of the day either. These results demonstrate that anthropogenic noise, even at frequencies well above the blue whales' sound production range, has a strong probability of eliciting changes in vocal behavior. The long-term implications of disruption in call production to blue whale foraging and other behaviors are currently not well understood.

  7. Nanotubes based on monolayer blue phosphorus

    KAUST Repository

    Montes Muñoz, Enrique

    2016-07-08

    We demonstrate structural stability of monolayer zigzag and armchair blue phosphorus nanotubes by means of molecular dynamics simulations. The vibrational spectrum and electronic band structure are determined and analyzed as functions of the tube diameter and axial strain. The nanotubes are found to be semiconductors with a sensitive indirect band gap that allows flexible tuning.

  8. Blue whales respond to anthropogenic noise.

    Science.gov (United States)

    Melcón, Mariana L; Cummins, Amanda J; Kerosky, Sara M; Roche, Lauren K; Wiggins, Sean M; Hildebrand, John A

    2012-01-01

    Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to stop calling at any time of day, showing no diel pattern in their sensitivity to sonar. Conversely, the likelihood of whales emitting calls increased when ship sounds were nearby. Whales did not show a differential response to ship noise as a function of the time of the day either. These results demonstrate that anthropogenic noise, even at frequencies well above the blue whales' sound production range, has a strong probability of eliciting changes in vocal behavior. The long-term implications of disruption in call production to blue whale foraging and other behaviors are currently not well understood.

  9. T's and Blues. Specialized Information Service.

    Science.gov (United States)

    Do It Now Foundation, Phoenix, AZ.

    This compilation of journal articles provides basic information on abuse of Talwin, a mild prescription painkiller (T's), and Pyribenzamine, a nonprescription antihistimine (Blues). These two drugs, taken in combination, produce an effect similar to that produced by heroin. Stories from "Drug Survival News,""Emergency…

  10. Avoiding the Negative: Blue Jeans Baseball

    Science.gov (United States)

    Maggard, Bob

    1978-01-01

    Blue Jeans Baseball, for eight- to twelve-year old children, is based on the concept that everyone plays. No coaches are allowed; everyone bats once per inning; defensive players rotate positions. These and other rules reduce the emphasis on competition and increase the emphasis on skill development. (MJB)

  11. Delta Blues Scholarship and Imperialist Nostalgia.

    Science.gov (United States)

    Nye, William P.

    When Delta blues are considered to be "folk music," the genre is inextricably tied to the neocolonial, sharecropping system of cotton production characteristic of the Mississippi Delta region between the Civil War and World War II. "Imperialist nostalgia," then, arises in accounts which pay primary and positive tribute to blues…

  12. Heparin sensing: Blue-chip binding

    Science.gov (United States)

    Shriver, Zachary; Sasisekharan, Ram

    2013-08-01

    Heparin is an anionic polysaccharide that has tremendous clinical importance as an anticoagulant. Several dyes have been developed that can detect heparin, and the latest example -- named Mallard Blue -- has now been shown to have excellent sensing properties under biologically relevant conditions.

  13. Blue straggler stars in dwarf spheroidal galaxies

    NARCIS (Netherlands)

    Mapelli, M.; Ripamonti, E.; Tolstoy, E.; Sigurdsson, S.; Irwin, M. J.; Battaglia, G.

    2007-01-01

    Blue straggler star (BSS) candidates have been observed in all old dwarf spheroidal galaxies (dSphs), however whether or not they are authentic BSSs or young stars has been a point of debate. To both address this issue and obtain a better understanding of the formation of BSSs in different environme

  14. Geographical Study of American Blues Culture

    Science.gov (United States)

    Strait, John B.

    2010-01-01

    Music is not often utilized in teaching geography, despite the fact that many scholars orient their research around analyzing both the historical and spatial dimensions of musical expression. This article reports on the use of a teaching module that utilizes blues culture as a lens to understand the geographical history of the United States. The…

  15. Prussian Blue Analogues of Reduced Dimensionality

    NARCIS (Netherlands)

    Gengler, Regis Y. N.; Toma, Luminita M.; Pardo, Emilio; Lloret, Francesc; Ke, Xiaoxing; Van Tendeloo, Gustaaf; Gournis, Dimitrios; Rudolf, Petra

    2012-01-01

    Mixed-valence polycyanides (Prussian Blue analogues) possess a rich palette of properties spanning from room-temperature ferromagnetism to zero thermal expansion, which can be tuned by chemical modifications or the application of external stimuli (temperature, pressure, light irradiation). While mol

  16. Formation Channels for Blue Straggler Stars

    CERN Document Server

    Davies, Melvyn B

    2014-01-01

    In this chapter we consider two formation channels for blue straggler stars: 1) the merger of two single stars via a collision, and 2) those produced via mass transfer within a binary. We review how computer simulations show that stellar collisions are likely to lead to relatively little mass loss and are thus effective in producing a young population of more-massive stars. The number of blue straggler stars produced by collisions will tend to increase with cluster mass. We review how the current population of blue straggler stars produced from primordial binaries decreases with increasing cluster mass. This is because exchange encounters with third, single stars in the most massive clusters tend to reduce the fraction of binaries containing a primary close to the current turn-off mass. Rather, their primaries tend to be somewhat more massive and have evolved off the main sequence, filling their Roche lobes in the past, often converting their secondaries into blue straggler stars (but more than 1 Gyr or so ag...

  17. Key Words in China Economic Blue Book

    Institute of Scientific and Technical Information of China (English)

    Tu Fei

    2009-01-01

    @@ With a fluctuating 2008 comes to an end,nOW new 2009 has approaehed to us.Recently、Analvsis and Forecast of China Economy in 2009(Blue Book of Ckina Economy),by the Economics Department or Chinese Academy of Social Sciences.

  18. Pigment Pad Dyeing of Polyester Ribbon%涤纶织带涂料轧染染色工艺

    Institute of Scientific and Technical Information of China (English)

    姜志新; 宋金龙; 唐三湘

    2011-01-01

    The effects of temperature,dosages of adhesives and auxiliary agents,and roller pressure on dyeing behaviors in pigment pad dyeing of polyester ribbon were studied.The results showed that color fastnesses and leveling of polyester ribbon were good in the conditions of pigment concentration less than 20 g/L,adhesive 40 g/L,dispersing agent 8 g/L,anti-migrant agent 15 g/L,roller pressure 0.2 MPa,and fixing at 160 ℃ for 2 minutes.Compared with that of thermosol dyeing,pigment pad dyeing reduced total cost such as water,power and steam for $1494 per day(20 hours/day),and 20 ton wastewater could be decreased.The pigment pad dyeing played an important role in developing ecological dyeing technology of polyester ribbon.%本文探讨了涤纶织带涂料轧染染色工艺中发色温度、粘合剂用量、助剂用量、轧辊压力对染色性能的影响。实验结果表明,涂料轧染染色时涂料用量宜小于20 g/L、粘合剂用量40 g/L、分散剂用量8 g/L、防泳移剂用量15 g/L,轧辊压力0.2 MPa,发色温度160℃,发色时间2分钟,涤纶织带的色牢度指标和染色匀染性较好。涂料轧染染色较热熔染色每天(20小时计算)可减少水、电、汽总成本1494元,同时污水排放减少20吨,对开发涤纶织带的生态染色技术具有重要作用。

  19. Principles of Communicative Task Design.

    Science.gov (United States)

    Nunan, David

    The use of the learning task as a basic planning and instructional tool for communicative second language instruction is discussed, and considerations and procedures for designing such tasks are outlined. A task is defined as a piece of classroom work that involves learners in comprehending, manipulating, producing, or interacting in the target…

  20. TASK: Let's Have a Party!

    Science.gov (United States)

    Rees, James

    2012-01-01

    In this article, the author describes a creative way to demystify contemporary art for students. TASK is artist Oliver Herring's creation, where participants actively interpret instructions found on little pieces of paper--what he calls "tasks." An art classroom has all the key ingredients for a TASK event: (1) people; (2) materials; (3) space;…