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Sample records for advanced ring pf-ar

  1. PF-AR upgrading project

    CERN Document Server

    Kasuga, T

    2002-01-01

    The upgrading project of the dedicated pulse X-ray source PF-AR has been completed by the end of the 2001 fiscal year. Machine commissioning exclusively using the injector linac was successfully accomplished in the beginning of January 2002. After fine tuning of the machine and cleaning of the vacuum system with the beams from the middle of January to the middle of March, routine operation for users has begun in April. The historical details, commissioning and results of the project are reported. (author)

  2. Measurement of storage ring motion at the advanced light source

    International Nuclear Information System (INIS)

    The mechanical stability of the Advanced Light Source storage ring is examined over a period of 1.5 years from the point of view of floor motion. The storage ring beam position monitor stability is examined under various operating conditions

  3. [INVITED] New advances in fiber cavity ring-down technology

    Science.gov (United States)

    Silva, S. O.; Magalhães, R.; Marques, M. B.; Frazão, O.

    2016-04-01

    A brief review in the cavity ring-down technique (CRD) is presented. In this review, there will only be considered the conventional fiber CRD configuration, i.e., there will only be presented researches involving cavities with two couplers with 99:1 ratios, due to the large amount of publications involving this spectroscopy method. The presented survey is divided in different topics related to the measurement of physical parameters, such as strain and temperature, curvature, pressure, refractive index, gas and biochemical sensing.

  4. Towards the ultimate storage ring: the lattice design for Beijing Advanced Photon Source

    CERN Document Server

    Gang, Xu

    2013-01-01

    A storage ring-based light source, Beijing Advanced Photon Source (BAPS) is proposed to store 5-GeV low-emittance electron beam and to provide high-brilliance coherent radiation. In this paper, we report our efforts of pushing down the emittance of BAPS to approach the so-called ultimate storage ring, while fixing the circumference to about 1200 m. To help dealing with the challenge of beam dynamics associated with the intrinsic very strong nonlinearities in an ultralow-emittance ring, a combination of several progressive technologies is used in the linear optics design and nonlinear optimization, such as modified theoretical minimum emittance cell with small-aperture magnets, quasi-3rd-order achromat, theoretical analyzer based on Lie Algebra and Hamiltonian analysis, multi-objective genetic algorithm, and frequency map analysis. These technologies enable us to obtain satisfactory beam dynamics in one lattice design with natural emittance of 75 pm.

  5. Commissioning of the University of Maryland Electron Ring (UMER): Advances toward multiturn operation

    International Nuclear Information System (INIS)

    The University of Maryland Electron Ring (UMER) is a low-energy, high current recirculator for beam physics research [M. Reiser et al., in Proceedings of the 1999 Particle Accelerator Conference, New York, NY (IEEE, New York, 1999), p. 234]. Ring construction is completed for multiturn operation of beams over a broad range of intensities and initial conditions. UMER is an extremely versatile experimental platform with a beam current of up to 100 mA and a pulse length as long as 100 ns. UMER is addressing issues in beam physics relevant to many applications that require intense beams of high quality, such as advanced concept accelerators, free electron lasers, spallation neutron sources, and future heavy-ion drivers for inertial fusion. The primary focus of this paper is to present experimental results in the areas of beam steering and multiturn operation of the ring. Unique beam steering algorithms now include measurement of the beam response matrix at each quadrupole and matrix inversion by singular value decomposition. With these advanced steering methods, transport of an intense beam over four turns (144 full lattice periods) of the ring has been achieved

  6. Towards the ultimate storage ring: The lattice design for Beijing Advanced Photon Source

    Institute of Scientific and Technical Information of China (English)

    XU Gang; JIAO Yi

    2013-01-01

    A storage ring-based light source,Beijing Advanced Photon Source (BAPS),is proposed to store a 5 GeV low-emittance electron beam and to provide high-brilliance coherent radiation.In this paper,we report our efforts of pushing down the emittance of BAPS to approach the so-called ultimate storage ring,while fixing the circumference to about 1200 m.To help deal with the challenge of beam dynamics associated with the intrinsic,very strong nonlinearities in an ultralow-emittance ring,a combination of several progressive technologies is used in the linear optics design and nonlinear optimization,such as a modified theoretical minimum emittance cell with smallaperture magnets,quasi-3rd-order achromat,theoretical analyzer based on Lie Algebra and Hamiltonian analysis,multi-objective genetic algorithm and frequency map analysis.These technologies enable us to obtain satisfactory beam dynamics in one lattice design with natural emittance of 75 pm.

  7. Digital closed orbit feedback system for the Advanced Photon Source storage ring

    International Nuclear Information System (INIS)

    Closed orbit feedback for the Advanced Photon Source (APS) storage ring employs unified global an local feedback systems for stabilization of particle and photon beams based on digital signal processing (DSP). Hardware and software aspects of the system will be described. In particular, we will discuss global and local orbit feedback algorithms, PID (proportional, integral, and derivative) control algorithm. application of digital signal processing to compensate for vacuum chamber eddy current effects, resolution of the interaction between global and local systems through decoupling, self-correction of the local bump closure error, user interface through the APS control system, and system performance in the frequency and time domains. The system hardware, including the DSPS, is distributed in 20 VNE crates around the ring, and the entire feedback system runs synchronously at 4-kHz sampling frequency in order to achieve a correction bandwidth exceeding 100 Hz. The required data sharing between the global and local feedback systems is facilitated via the use of fiber-optically-networked reflective memories

  8. Digital closed orbit feedback system for the advanced photon source storage ring

    International Nuclear Information System (INIS)

    The Advanced Photon Source (APS) is a dedicated third-generation synchrotron light source with a nominal energy of 7 GeV and a circumference of 1104 m. The closed orbit feedback system for the APS storage ring employs unified global and local feedback systems for stabilization of particle and photon beams based on digital signal processing (DSP). Hardware and software aspects of the system will be described in this paper. In particular, we will discuss global and local orbit feedback algorithms, PID (proportional, integral, and derivative) control algorithm, application of digital signal processing to compensate for vacuum chamber eddy current effects, resolution of the interaction between global and local systems through decoupling, self-correction of the local bump closure error, user interface through the APS control system, and system performance in the frequency and time domains. The system hardware including the DSPs is distributed in 20 VME crates around the ring, and the entire feedback system runs synchronously at 4-kHz sampling frequency in order to achieve a correction bandwidth exceeding 100 Hz. The required data sharing between the global and local feedback systems is facilitated via the use of fiber-optically-networked reflective memories

  9. NATO Advanced Study Institute on Ring-opening Metathesis Polymerization of Olefins and Polymerization of Alkynes

    CERN Document Server

    1998-01-01

    The first NATO Advanced Study Institute on Olefin Metathesis and Polymerization Catalysts was held on September 10-22, 1989 in Akcay, Turkey. Based on the fundamental research of RRSchrock, RGrubbs and K.B.Wagener in the field of ring opening metathesis polymerization (ROMP), acyclic diene metathesis (ADMET) and alkyne polymerization, these areas gained growing interest within the last years. Therefore the second NATO-ASI held on metathesis reactions was on Ring Opening Metathesis Po­ lymerization of Olefins and Polymerization of Alkynes on September 3-16, 1995 in Akcay, Turkey. The course joined inorganic, organic and polymer chemists to exchange their knowledge in this field. This volume contains the main and short lectures held in Akcay. To include ADMET reactions better into the title of this volume we changed it into: Metathesis Polymerization of Olefins and Alkyne Polymerization. This volume is addressed to research scientists, but also to those who start to work in the area of olefin metathesis and al...

  10. X-Ray microprobe characterization of materials: the case for undulators on advanced storage rings

    International Nuclear Information System (INIS)

    The unique properties of X-rays offer many advantages over electrons and other charged particles for the microcharacterization of materials. X-rays are more efficient in exciting characteristic X-ray fluorescence and produce higher fluorescent signals to backgrounds than obtained with electrons. Detectable limits for X-rays are a few parts per billion and are 10-3 to 10-5 less than obtained with electrons. Energy deposition in the sample by X-rays is 10-3 to 10-4 less than for electrons for the same detectable concentration. High-brightness storage rings, especially in the 6 GeV class with undulators, will be approximately 103 brighter in the X-ray energy range from 5 keV to 35 keV than existing storage rings and provide for X-ray microprobes that are as bright as the most advanced electron probes. Such X-ray microprobes will produce unprecedented low levels of detection in diffraction, EXAFS, Auger, and photoelectron spectoscopies for both chemical characterization and elemental identification. These major improvements in microcharacterization capabilities will be wide-ranging ramifications not only in materials science but also in physics, chemistry, geochemistry, biology, and medicine

  11. A Survey on Silicon PUFs and Recent Advances in Ring Oscillator PUFs

    Institute of Scientific and Technical Information of China (English)

    张吉良; 屈钢; 吕勇强; 周强

    2014-01-01

    Silicon physical unclonable function (PUF) is a popular hardware security primitive that exploits the intrinsic variation of IC manufacturing process to generate chip-unique information for various security related applications. For example, the PUF information can be used as a chip identifier, a secret key, the seed for a random number generator, or the response to a given challenge. Due to the unpredictability and irreplicability of IC manufacturing variation, silicon PUF has emerged as a promising hardware security primitive and gained a lot of attention over the past few years. In this article, we first give a survey on the current state-of-the-art of silicon PUFs, then analyze known attacks to PUFs and the countermeasures. After that we discuss PUF-based applications, highlight some recent research advances in ring oscillator PUFs, and conclude with some challenges and opportunities in PUF research and applications.

  12. Vacuum system development status for the APS [Advanced Photon Source] storage ring

    International Nuclear Information System (INIS)

    The status of the design and fabrication of a prototype sector of the storage ring vacuum system for the Advanced Photon Source is described. The 26.5-m-long prototype sector will be assembled within a full-scale magnet and tunnel mockup to study interspacial component relationships for maintenance, as well as the vacuum system operational performance. Each completed vacuum section is mounted as an integral part of the modular structure that contains the magnets and magnet power supplies on a common base. Unique automatic machine welding designs and techniques are employed in the fabrication of the aluminium vacuum chambers from extrusions. Special chamber bending procedures and measurements checks are used to maintain the required flatness of the insider chamber light gap surfaces. Photo-electron yields due to low-energy photons in the narrow channel gap of the vacuum chamber and their potential effects on the overall outgassing rate are found to be negligible. 9 refs., 5 figs

  13. UHV seal studies for the advanced photon source storage ring vacuum system

    International Nuclear Information System (INIS)

    The Advanced Photon Source (APS) Storage Ring Vacuum Chambers (SRVC) are constructed of aluminum. The chamber design incorporates aluminum alloy 2219-T87 Conflat flanges welded to an aluminum alloy 6063-T5 extruded chamber body. Vacuum connections to the aluminum Conflat chamber flanges are by means of 304 stainless steel Conflat flanges. To evaluate the Conflat seal assemblies relative to vacuum bake cycles, a Conflat Bake Test Assembly (CBTA) was constructed, and thermal cycling tests were performed between room temperature and 150 degrees C on both stainless steel to aluminum Conflat assemblies and aluminum to aluminum Conflat assemblies. A Helicoflex Bake Test Assembly (HBTA) was similarly constructed to evaluate Helicoflex seals. Both Conflat and Helicoflex seals were studied in a SRVC Sector String Test arrangement of five SRVC sections. The CBTA, HBTA and SRVC tests and their results are reported. 3 refs., 2 figs., 2 tabs

  14. UHV seal studies for the Advanced Photon Source storage ring vacuum system

    International Nuclear Information System (INIS)

    The Advanced Photon Source (APS) Storage Ring Vacuum Chambers (SRVC) are constructed of aluminum. The chamber design incorporates aluminum alloy 2219-T87 Conflat flanges welded to an aluminum alloy 60603-T5 extruded chamber body. Vacuum connections to the aluminum Conflat chamber flanges are by means of 304 stainless steel Conflat flanges. To evaluate the Conflat seal assemblies relative to vacuum bake cycles, a Conflat Bake Test Assembly (CBTA) was constructed, and thermal cycling tests were performed between room temperature and 150 C on both stainless steel to aluminum Conflat assemblies and aluminum to aluminum Conflat assemblies. A Helicoflex Bake Test Assembly (HBTA) was similarly constructed to evaluate Helicoflex seals. Both Conflat and Helicoflex seals were studied in a SRVC Sector String Test arrangement of five SRVC sections. The CBTA, HBTA and SRVC tests and their results are reported

  15. Second advanced ICFA beam dynamics workshop on aperture-related limitations of the performance and beam lifetime in storage rings

    International Nuclear Information System (INIS)

    These proceedings contain the papers presented at the 'Second advanced beam dynamics workshop on aperture-related limitations of the performance and beam lifetime in storage rings', which was organized in Lugano, Switzerland, from 11 to 16 April 1988, by the Beam Dynamics Panel of the International Committee for Future Accelerators (ICFA). The papers cover experiments on existing accelerators, analytical methods for determining amplitude limitations, criteria for the properties of the circulating beam and for the quality of accelerator components, and compensation schemes for field defects. (orig.)

  16. Topological rings

    CERN Document Server

    Warner, S

    1993-01-01

    This text brings the reader to the frontiers of current research in topological rings. The exercises illustrate many results and theorems while a comprehensive bibliography is also included. The book is aimed at those readers acquainted with some very basic point-set topology and algebra, as normally presented in semester courses at the beginning graduate level or even at the advanced undergraduate level. Familiarity with Hausdorff, metric, compact and locally compact spaces and basic properties of continuous functions, also with groups, rings, fields, vector spaces and modules, and with Zorn''s Lemma, is also expected.

  17. Physics of quantum rings

    CERN Document Server

    Fomin, Vladimir M

    2013-01-01

    This book deals with a new class of materials, quantum rings. Innovative recent advances in experimental and theoretical physics of quantum rings are based on the most advanced state-of-the-art fabrication and characterization techniques as well as theoretical methods. The experimental efforts allow to obtain a new class of semiconductor quantum rings formed by capping self-organized quantum dots grown by molecular beam epitaxy. Novel optical and magnetic properties of quantum rings are associated with non-trivial topologies at the nanoscale. An adequate characterization of quantum rings is po

  18. Groups, rings, modules

    CERN Document Server

    Auslander, Maurice

    2014-01-01

    This classic monograph is geared toward advanced undergraduates and graduate students. The treatment presupposes some familiarity with sets, groups, rings, and vector spaces. The four-part approach begins with examinations of sets and maps, monoids and groups, categories, and rings. The second part explores unique factorization domains, general module theory, semisimple rings and modules, and Artinian rings. Part three's topics include localization and tensor products, principal ideal domains, and applications of fundamental theorem. The fourth and final part covers algebraic field extensions

  19. Ring Theory

    CERN Document Server

    Jara, Pascual; Torrecillas, Blas

    1988-01-01

    The papers in this proceedings volume are selected research papers in different areas of ring theory, including graded rings, differential operator rings, K-theory of noetherian rings, torsion theory, regular rings, cohomology of algebras, local cohomology of noncommutative rings. The book will be important for mathematicians active in research in ring theory.

  20. Storage Ring EDM Experiments

    Science.gov (United States)

    Semertzidis, Yannis K.

    2016-04-01

    Dedicated storage ring electric dipole moment (EDM) methods show great promise advancing the sensitivity level by a couple orders of magnitude over currently planned hadronic EDM experiments. We describe the present status and recent updates of the field.

  1. Orbit correction using an eigenvector method with constraints for synchrotron radiation sources

    Science.gov (United States)

    Harada, Kentaro; Obina, Takashi; Kobayashi, Yukinori; Nakamura, Norio; Takaki, Hiroyuki; Sakai, Hiroshi

    2009-06-01

    An eigenvector method with constraints (EVC) is proposed as a new orbit correction scheme for synchrotron light sources. EVC efficiently corrects the global orbit in a storage ring, and can simultaneously perform exact correction of local orbits without deterioration of the global orbit. To demonstrate the advantages of EVC over the ordinary eigenvector method (EV), we carried out experimental studies at the Photon Factory storage ring (PF-ring) and the Photon Factory Advanced Ring (PF-AR) at the High Energy Accelerator Research Organization (KEK). The performance of EVC was systematically examined at PF-ring and PF-AR. The experimental results agreed well with the simulated ones. Consequently, we confirmed that EVC easily realized orbit correction for both global and local orbits, and that it was very effective for the beam stabilization of synchrotron radiation (SR) sources.

  2. Orbit correction using an eigenvector method with constraints for synchrotron radiation sources

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Kentaro [Photon Factory, High Energy Accelerator Research Organization, 1-1, Oho, Tsukuba, Ibaraki 305-0801 (Japan)], E-mail: kentaro.harada@kek.jp; Obina, Takashi; Kobayashi, Yukinori [Photon Factory, High Energy Accelerator Research Organization, 1-1, Oho, Tsukuba, Ibaraki 305-0801 (Japan); Nakamura, Norio; Takaki, Hiroyuki; Sakai, Hiroshi [Institute for Solid State Physics, University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan)

    2009-06-11

    An eigenvector method with constraints (EVC) is proposed as a new orbit correction scheme for synchrotron light sources. EVC efficiently corrects the global orbit in a storage ring, and can simultaneously perform exact correction of local orbits without deterioration of the global orbit. To demonstrate the advantages of EVC over the ordinary eigenvector method (EV), we carried out experimental studies at the Photon Factory storage ring (PF-ring) and the Photon Factory Advanced Ring (PF-AR) at the High Energy Accelerator Research Organization (KEK). The performance of EVC was systematically examined at PF-ring and PF-AR. The experimental results agreed well with the simulated ones. Consequently, we confirmed that EVC easily realized orbit correction for both global and local orbits, and that it was very effective for the beam stabilization of synchrotron radiation (SR) sources.

  3. Saturn's Rings are Fractal

    OpenAIRE

    Li, Jun; Ostoja-Starzewski, Martin

    2012-01-01

    Over the past few decades, various conjectures were advanced that Saturn's rings are Cantor-like sets, although no convincing fractal analysis of actual images has ever appeared. We focus on the images sent by the Cassini spacecraft mission: slide #42 "Mapping Clumps in Saturn's Rings" and slide #54 "Scattered Sunshine". Using the box-counting method, we determine the fractal dimension of rings seen here (and in several other images from the same source) to be consistently about 1.6~1.7. This...

  4. Ring theory

    CERN Document Server

    Rowen, Louis H

    1991-01-01

    This is an abridged edition of the author's previous two-volume work, Ring Theory, which concentrates on essential material for a general ring theory course while ommitting much of the material intended for ring theory specialists. It has been praised by reviewers:**""As a textbook for graduate students, Ring Theory joins the best....The experts will find several attractive and pleasant features in Ring Theory. The most noteworthy is the inclusion, usually in supplements and appendices, of many useful constructions which are hard to locate outside of the original sources....The audience of non

  5. Planetary Rings

    CERN Document Server

    Tiscareno, Matthew S

    2011-01-01

    Planetary rings are the only nearby astrophysical disks, and the only disks that have been investigated by spacecraft. Although there are significant differences between rings and other disks, chiefly the large planet/ring mass ratio that greatly enhances the flatness of rings (aspect ratios as small as 1e-7), understanding of disks in general can be enhanced by understanding the dynamical processes observed at close-range and in real-time in planetary rings. We review the known ring systems of the four giant planets, as well as the prospects for ring systems yet to be discovered. We then review planetary rings by type. The main rings of Saturn comprise our system's only dense broad disk and host many phenomena of general application to disks including spiral waves, gap formation, self-gravity wakes, viscous overstability and normal modes, impact clouds, and orbital evolution of embedded moons. Dense narrow rings are the primary natural laboratory for understanding shepherding and self-stability. Narrow dusty...

  6. Planetary Rings

    Science.gov (United States)

    Gordon, M. K.; Araki, S.; Black, G. J.; Bosh, A. S.; Brahic, A.; Brooks, S. M.; Charnoz, S.; Colwell, J. E.; Cuzzi, J. N.; Dones, L.; Durisen, R. H.; Esposito, L. W.; Ferrari, C.; Festou, M.; French, R. G.; Giuliatti-Winter, S. M.; Graps, A. L.; Hamilton, D. P.; Horanyi, M.; Karjalainen, R. M.; Krivov, A. V.; Krueger, H.; Larson, S. M.; Levison, H. F.; Lewis, M. C.; Lissauer, J. J.; Murray, C. D.; Namouni, F.; Nicholson, P. D.; Olkin, C. B.; Poulet, F.; Rappaport, N. J.; Salo, H. J.; Schmidt, J.; Showalter, M. R.; Spahn, F.; Spilker, L. J.; Srama, R.; Stewart, G. R.; Yanamandra-Fisher, P.

    2002-08-01

    The past two decades have witnessed dramatic changes in our view and understanding of planetary rings. We now know that each of the giant planets in the Solar System possesses a complex and unique ring system. Recent studies have identified complex gravitational interactions between the rings and their retinues of attendant satellites. Among the four known ring systems, we see elegant examples of Lindblad and corotation resonances (first invoked in the context of galactic disks), electromagnetic resonances, spiral density waves and bending waves, narrow ringlets which exhibit internal modes due to collective instabilities, sharp-edged gaps maintained via tidal torques from embedded moonlets, and tenuous dust belts created by meteoroid impact onto, or collisions between, parent bodies. Yet, as far as we have come, our understanding is far from complete. The fundamental questions confronting ring scientists at the beginning of the twenty-first century are those regarding the origin, age and evolution of the various ring systems, in the broadest context. Understanding the origin and age requires us to know the current ring properties, and to understand the dominant evolutionary processes and how they influence ring properties. Here we discuss a prioritized list of the key questions, the answers to which would provide the greatest improvement in our understanding of planetary rings. We then outline the initiatives, missions, and other supporting activities needed to address those questions, and recommend priorities for the coming decade in planetary ring science.

  7. Uranus rings and two moons

    Science.gov (United States)

    1986-01-01

    Voyager 2 has discovered two 'shepherd' satellites associated with the rings of Uranus. The two moons -- designated 1986U7 and 1986U8 -- are seen here on either side of the bright epsilon ring; all nine of the known Uranian rings are visible. The image was taken Jan. 21, 1986, at a distance of 4.1 million kilometers (2.5 million miles) and resolution of about 36 km (22 mi). The image was processed to enhance narrow features. The epsilon ring appears surrounded by a dark halo as a result of this processing; occasional blips seen on the ring are also artifacts. Lying inward from the epsilon ring are the delta, gamma and eta rings; then the beta and alpha rings; and finally the barely visible 4, 5 and 6 rings. The rings have been studied since their discovery in 1977, through observations of how they diminish the light of stars they pass in front of. This image is the first direct observation of all nine rings in reflected sunlight. They range in width from about 100 km (60 mi) at the widest part of the epsilon ring to only a few kilometers for most of the others. The discovery of the two ring moons 1986U7 and 1986U8 is a major advance in our understanding of the structure of the Uranian rings and is in good agreement with theoretical predictions of how these narrow rings are kept from spreading out. Based on likely surface brightness properties, the moons are of roughly 2O- and 3O-km diameter, respectively. The Voyager project is managed for NASA by the Jet Propulsion Laboratory.

  8. Topics in commutative ring theory

    CERN Document Server

    Watkins, John J

    2009-01-01

    Topics in Commutative Ring Theory is a textbook for advanced undergraduate students as well as graduate students and mathematicians seeking an accessible introduction to this fascinating area of abstract algebra. Commutative ring theory arose more than a century ago to address questions in geometry and number theory. A commutative ring is a set-such as the integers, complex numbers, or polynomials with real coefficients--with two operations, addition and multiplication. Starting from this simple definition, John Watkins guides readers from basic concepts to Noetherian rings-one of

  9. SUPRAMITRAL RING

    Directory of Open Access Journals (Sweden)

    Rajesh G

    2011-11-01

    Full Text Available Supra mitral ring is a rare cause for congenital mitral valve obstr uction. The reported incidence of supramitral ring is 0.2-0.4% in general population and 8% in patients with congenital mitral valve disease. The condition is characterized by an abnormal ridge of connective tissue often circumferential in shape ,on the atrial side of the mitral valve encroaching on the orifice of the mitral valve. It may adhere to the leaflets of the valve and restrict their movements. Although a supramitral ring may be rarely nonobstructive, it often results in mitral valve inflow obstruction.

  10. Determinantal rings

    CERN Document Server

    Bruns, Winfried

    1988-01-01

    Determinantal rings and varieties have been a central topic of commutative algebra and algebraic geometry. Their study has attracted many prominent researchers and has motivated the creation of theories which may now be considered part of general commutative ring theory. The book gives a first coherent treatment of the structure of determinantal rings. The main approach is via the theory of algebras with straightening law. This approach suggest (and is simplified by) the simultaneous treatment of the Schubert subvarieties of Grassmannian. Other methods have not been neglected, however. Principal radical systems are discussed in detail, and one section is devoted to each of invariant and representation theory. While the book is primarily a research monograph, it serves also as a reference source and the reader requires only the basics of commutative algebra together with some supplementary material found in the appendix. The text may be useful for seminars following a course in commutative ring theory since a ...

  11. Almost ring theory

    CERN Document Server

    2003-01-01

    This book develops thorough and complete foundations for the method of almost etale extensions, which is at the basis of Faltings' approach to p-adic Hodge theory. The central notion is that of an "almost ring". Almost rings are the commutative unitary monoids in a tensor category obtained as a quotient V-Mod/S of the category V-Mod of modules over a fixed ring V; the subcategory S consists of all modules annihilated by a fixed ideal m of V, satisfying certain natural conditions. The reader is assumed to be familiar with general categorical notions, some basic commutative algebra and some advanced homological algebra (derived categories, simplicial methods). Apart from these general prerequisites, the text is as self-contained as possible. One novel feature of the book - compared with Faltings' earlier treatment - is the systematic exploitation of the cotangent complex, especially for the study of deformations of almost algebras.

  12. Review of Linac-Ring Type Collider Proposals

    CERN Document Server

    Akay, A N; Sultansoy, S

    2009-01-01

    There are three possibly types of particle colliders schemes: familiar (well known) ring-ring colliders, less familiar however sufficiently advanced linear colliders and less familiar and less advanced linac-ring type colliders. The aim of this paper is two-fold: to present possibly complete list of papers on linac-ring type collider proposals and to emphasize the role of linac-ring type machines for future HEP research.

  13. The Structure of Saturn's Rings

    Science.gov (United States)

    Colwell, J. E.; Nicholson, P. D.; Tiscareno, M. S.; Murray, C. D.; French, R. G.; Marouf, E. A.

    Our understanding of the structure of Saturn's rings has evolved steadily since their discovery by Galileo Galilei in 1610. With each advance in observations of the rings over the last four centuries, new structure has been revealed, starting with the recognition that the rings are a disk by Huygens in 1656 through discoveries of the broad organization of the main rings and their constituent gaps and ringlets to Cassini observations that indirectly reveal individual clumps of particles tens of meters in size. The variety of structure is as broad as the range in scales. The main rings have distinct characteristics on a spatial scale of 104 km that suggest dramatically different evolution and perhaps even different origins. On smaller scales, the A and C ring and Cassini Division are punctuated by gaps from tens to hundreds of kilometer across, while the B ring is littered with unexplained variations in optical depth on similar scales. Moons are intimately involved with much of the structure in the rings. The outer edges of the A and B rings are shepherded and sculpted by resonances with the Janus—Epimetheus coorbitals and Mimas, respectively. Density waves at the locations of orbital resonances with nearby and embedded moons make up the majority of large-scale features in the A ring. Moons orbiting within the Encke and Keeler gaps in the A ring create those gaps and produce wakes in the nearby ring. Other gaps and wave-like features await explanation. The largest ring particles, while not massive enough to clear a gap, produce localized propeller-shaped disturbances hundreds of meters long. Particles throughout the A and B rings cluster into strands or self-gravity wakes tens of meters across that are in equilibrium between gravitational accretion and Keplerian shear. In the peaks of strong density waves particles pile together in a cosmic traffic jam that results in kilometer-long strands that may be larger versions of self-gravity wakes. The F ring is a showcase

  14. Ring interferometry

    CERN Document Server

    Malykin, Grigorii B; Zhurov, Alexei

    2013-01-01

    This monograph is devoted to the creation of a comprehensive formalism for quantitative description of polarized modes' linear interaction in modern single-mode optic fibers. The theory of random connections between polarized modes, developed in the monograph, allows calculations of the zero shift deviations for a fiber ring interferometer. The monograph addresses also the

  15. Advanced Ring-Shaped Microelectrode Assay Combined with Small Rectangular Electrode for Quasi-In vivo Measurement of Cell-to-Cell Conductance in Cardiomyocyte Network

    Science.gov (United States)

    Nomura, Fumimasa; Kaneko, Tomoyuki; Hamada, Tomoyo; Hattori, Akihiro; Yasuda, Kenji

    2013-06-01

    To predict the risk of fatal arrhythmia induced by cardiotoxicity in the highly complex human heart system, we have developed a novel quasi-in vivo electrophysiological measurement assay, which combines a ring-shaped human cardiomyocyte network and a set of two electrodes that form a large single ring-shaped electrode for the direct measurement of irregular cell-to-cell conductance occurrence in a cardiomyocyte network, and a small rectangular microelectrode for forced pacing of cardiomyocyte beating and for acquiring the field potential waveforms of cardiomyocytes. The advantages of this assay are as follows. The electrophysiological signals of cardiomyocytes in the ring-shaped network are superimposed directly on a single loop-shaped electrode, in which the information of asynchronous behavior of cell-to-cell conductance are included, without requiring a set of huge numbers of microelectrode arrays, a set of fast data conversion circuits, or a complex analysis in a computer. Another advantage is that the small rectangular electrode can control the position and timing of forced beating in a ring-shaped human induced pluripotent stem cell (hiPS)-derived cardiomyocyte network and can also acquire the field potentials of cardiomyocytes. First, we constructed the human iPS-derived cardiomyocyte ring-shaped network on the set of two electrodes, and acquired the field potential signals of particular cardiomyocytes in the ring-shaped cardiomyocyte network during simultaneous acquisition of the superimposed signals of whole-cardiomyocyte networks representing cell-to-cell conduction. Using the small rectangular electrode, we have also evaluated the response of the cell network to electrical stimulation. The mean and SD of the minimum stimulation voltage required for pacing (VMin) at the small rectangular electrode was 166+/-74 mV, which is the same as the magnitude of amplitude for the pacing using the ring-shaped electrode (179+/-33 mV). The results showed that the

  16. Nobel Chemistry in the Laboratory: Synthesis of a Ruthenium Catalyst for Ring-Closing Olefin Metathesis--An Experiment for the Advanced Inorganic or Organic Laboratory

    Science.gov (United States)

    Greco, George E.

    2007-01-01

    An experiment for the upper-level undergraduate laboratory is described in which students synthesize a ruthenium olefin metathesis catalyst, then use the catalyst to carry out the ring-closing metathesis of diethyl diallylmalonate. The olefin metathesis reaction was the subject of the 2005 Nobel Prize in chemistry. The catalyst chosen for this…

  17. Moving ring reactor 'Karin-1'

    International Nuclear Information System (INIS)

    The conceptual design of a moving ring reactor ''Karin-1'' has been carried out to advance fusion system design, to clarify the research and development problems, and to decide their priority. In order to attain these objectives, a D-T reactor with tritium breeding blanket is designed, a commercial reactor with net power output of 500 MWe is designed, the compatibility of plasma physics with fusion engineering is demonstrated, and some other guideline is indicated. A moving ring reactor is composed mainly of three parts. In the first formation section, a plasma ring is formed and heated up to ignition temperature. The plasma ring of compact torus is transported from the formation section through the next burning section to generate fusion power. Then the plasma ring moves into the last recovery section, and the energy and particles of the plasma ring are recovered. The outline of a moving ring reactor ''Karin-1'' is described. As a candidate material for the first wall, SiC was adopted to reduce the MHD effect and to minimize the interaction with neutrons and charged particles. The thin metal lining was applied to the SiC surface to solve the problem of the compatibility with lithium blanket. Plasma physics, the engineering aspect and the items of research and development are described. (Kako, I.)

  18. Ion Rings for Magnetic Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Greenly, John, B.

    2005-07-31

    This Final Technical Report presents the results of the program, Ion Rings for Magnetic Fusion, which was carried out under Department of Energy funding during the period August, 1993 to January, 2005. The central objective of the program was to study the properties of field-reversed configurations formed by ion rings. In order to reach this objective, our experimental program, called the Field-reversed Ion Ring Experiment, FIREX, undertook to develop an efficient, economical technology for the production of field-reversed ion rings. A field-reversed configuration (FRC) in which the azimuthal (field-reversing) current is carried by ions with gyro-radius comparable to the magnetic separatrix radius is called a field-reversed ion ring. A background plasma is required for charge neutralization of the ring, and this plasma will be confined within the ring's closed magnetic flux. Ion rings have long been of interest as the basis of compact magnetic fusion reactors, as the basis for a high-power accelerator for an inertial fusion driver, and for other applications of high power ion beams or plasmas of high energy density. Specifically, the FIREX program was intended to address the longstanding question of the contribution of large-orbit ions to the observed stability of experimental FRCs to the MHD tilt mode. Typical experimental FRCs with s {approx} 2-4, where s is the ratio of separatrix radius to ion gyro-radius, have been stable to tilting, but desired values for a fusion reactor, s > 20, should be unstable. The FIREX ring would consist of a plasma with large s for the background ions, but with s {approx} 1 for the ring ions. By varying the proportions of these two populations, the minimum proportion of large-orbit ions necessary for stability could be determined. The incorporation of large-orbit ions, perhaps by neutral-beam injection, into an FRC has been advanced for the purpose of stabilizing, heating, controlling angular momentum, and aiding the formation

  19. New methodologies at PF AR-NW12A: the implementation of high-pressure macromolecular crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Chavas, Leonard Michel Gabriel, E-mail: leonard.chavas@kek.jp [PF/IMSS/KEK, 1-1 Oho, Tsukuba, Ibaraki 300-0801 (Japan); Nagae, Tadayuki [Nagoya University, Nagoya, Aichi 464-8603 (Japan); Nagoya University, Nagoya, Aichi 464-8603 (Japan); Yamada, Hiroyuki [Nagoya University, Nagoya, Aichi 464-8603 (Japan); Watanabe, Nobuhisa [Nagoya University, Nagoya, Aichi 464-8603 (Japan); Nagoya University, Furo-cho Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Yamada, Yusuke; Hiraki, Masahiko; Matsugaki, Naohiro [PF/IMSS/KEK, 1-1 Oho, Tsukuba, Ibaraki 300-0801 (Japan)

    2013-11-01

    The evolution of AR-NW12A into a multi-purpose end-station with optional high-pressure crystallography is described. The macromolecular crystallography (MX) beamline AR-NW12A is evolving from its original design of high-throughput crystallography to a multi-purpose end-station. Among the various options to be implemented, great efforts were made in making available high-pressure MX (HPMX) at the beamline. High-pressure molecular biophysics is a developing field that attracts the interest of a constantly growing scientific community. A plethora of activities can benefit from high pressure, and investigations have been performed on its applicability to study multimeric complex assemblies, compressibility of proteins and their crystals, macromolecules originating from extremophiles, or even the trapping of higher-energy conformers for molecules of biological interest. Recent studies using HPMX showed structural hydrostatic-pressure-induced changes in proteins. The conformational modifications could explain the enzymatic mechanism differences between proteins of the same family, living at different environmental pressures, as well as the initial steps in the pressure-denaturation process that have been attributed to water penetration into the protein interior. To facilitate further HPMX, while allowing access to various individualized set-ups and experiments, the AR-NW12A sample environment has been revisited. Altogether, the newly added implementations will bring a fresh breath of life to AR-NW12A and allow the MX community to experiment in a larger set of fields related to structural biology.

  20. Prime rings with PI rings of constants

    CERN Document Server

    Kharchenko, V K; Rodríguez-Romo, S

    1996-01-01

    It is shown that if the ring of constants of a restricted differential Lie algebra with a quasi-Frobenius inner part satisfies a polynomial identity (PI) then the original prime ring has a generalized polynomial identitiy (GPI). If additionally the ring of constants is semiprime then the original ring is PI. The case of a non-quasi-Frobenius inner part is also considered.

  1. Weakly Dual Rings

    Institute of Scientific and Technical Information of China (English)

    魏俊潮; 孙建华

    2004-01-01

    In This paper, the concept of weakly dual ring is introduced, which is a proper generalization of the dual ring. If R is a right weakly dual ring, then (1)Z(RR) = J(R); (2) If R is also a zero-division power ring, then R is a right AP-injective ring. In addition, some properties of weakly dual rings are given.

  2. Radical theory of rings

    CERN Document Server

    Gardner, JW

    2003-01-01

    Radical Theory of Rings distills the most noteworthy present-day theoretical topics, gives a unified account of the classical structure theorems for rings, and deepens understanding of key aspects of ring theory via ring and radical constructions. Assimilating radical theory's evolution in the decades since the last major work on rings and radicals was published, the authors deal with some distinctive features of the radical theory of nonassociative rings, associative rings with involution, and near-rings. Written in clear algebraic terms by globally acknowledged authorities, the presentation

  3. Recent advances in long-term climate and moisture reconstructions from the Baltic region: Exploring the potential for a new multi-millennial tree-ring chronology

    Science.gov (United States)

    Edvardsson, Johannes; Corona, Christophe; Mažeika, Jonas; Pukienė, Rutile; Stoffel, Markus

    2016-01-01

    This study presents the first results from an ongoing initiative to develop a multi-millennial Baltic tree-ring width (TRW) chronology consisting of 12 floating records from subfossil Scots pines (Pinus sylvestris L.) extracted from three Lithuanian peat-mining areas. The floating series have been complemented with absolutely dated TRW chronologies which were obtained from living trees growing in unmanaged and unexploited peatland areas adjacent to each of the above study sites. The subfossil material has been dated by radiocarbon and shows a temporal spread over the last 6000 years, with assemblages of trees during the Holocene Thermal Maximum (HTM; 8000-4000 BP) and the onset of the Medieval Warm Period (MWP, AD 900-1350). Annual tree growth and sample replication of peatland pines reflect moisture variations and long-term climate variability. The importance of extending the TRW chronologies should not therefore be underestimated as (1) climate records of comparable length and resolution do not exist for the Baltic region, but also as (2) a result of a widespread lack of detailed moisture proxies spanning several millennia. Our data clearly show that a 6000-yr, continuous pine chronology from the Baltic region is a realistic objective, and would doubtlessly fill a major geographic gap in an ecologically sensitive region located at the interface between the temperate and boreal vegetation zones.

  4. Alternative loop rings

    CERN Document Server

    Goodaire, EG; Polcino Milies, C

    1996-01-01

    For the past ten years, alternative loop rings have intrigued mathematicians from a wide cross-section of modern algebra. As a consequence, the theory of alternative loop rings has grown tremendously. One of the main developments is the complete characterization of loops which have an alternative but not associative, loop ring. Furthermore, there is a very close relationship between the algebraic structures of loop rings and of group rings over 2-groups. Another major topic of research is the study of the unit loop of the integral loop ring. Here the interaction between loop rings and group ri

  5. Advances in Analysis of Environmental Pollution by Using Tree-ring Data%利用树木年轮资料分析环境污染的研究进展

    Institute of Scientific and Technical Information of China (English)

    杨银科; 黄强; 王文科; 宋慧明; 杨红斌

    2011-01-01

    Analysis of environmental pollution based on tree-ring data is an important direction in dendrochronology. Based on the theory of the information record, pollution history inversion and analysis, the advances in researching environmental pollution by using tree-ring data both at home and abroad were reviewed. As indicated by the analysis, the dendrochemistry analysis of environmental pollution involved multiple factors, based on the mature dendroclimatology method, we should pay attention to the introduction of new techniques and methods and constantly improve the reliability of the research results, so as to provide long sequence of basis data for environmental pollution research.%利用树木年轮资料分析环境污染是树木年轮学研究的一个重要方向.在理解树轮对环境污染的信息记录,污染历史反演与分析等理论的基础上,综述了国内外利用树轮资料研究环境污染的研究进展.分析认为,利用树轮化学方法分析环境污染应综合考虑多方面响应因素,借鉴成熟的树轮气候学的研究方法,注重新技术、新方法的引入,不断提高研究结果的可靠度,为环境污染研究提供丰富的长序列基础数据.

  6. Role of Friction in Cold Ring Rolling

    Institute of Scientific and Technical Information of China (English)

    He YANG; Lianggang GUO; Mei ZHAN

    2005-01-01

    Cold ring rolling is an advanced but complex metal forming process under coupled effects with multi-factors, such as geometry sizes of rolls and ring blank, material, forming process parameters and friction, etc. Among these factors,friction between rolls and ring blank plays animportant role in keeping the stable forming of cold ring rolling. An analytical method was firstly presented for proximately determining the critical friction coefficient of stable forming and then a method was proposed to determine thecritical friction coefficient by combining analytical method with numerical simulation. And the influence of friction coefficient on the quality of end-plane and side spread of ring,rolling force, rolling moment and metal flow characteristic in the cold ring rolling process have been explored using the three dimensional (3D) numerical simulation based on the elastic-plastic dynamic finite element method (FEM)under the ABAQUS software environment, and the results show that increasing the friction on the contact surfaces between rolls and ring blank is useful not only for improving the stability of cold ring rolling but also for improving the geometry and dimension precision of deformed ring.

  7. On JB-Rings

    Institute of Scientific and Technical Information of China (English)

    Huanyin CHEN

    2007-01-01

    A ring R is a QB-ring provided that aR + bR = R with a, b ∈ R implies that there exists a y ∈ R such that a+by ∈ R-1q. It is said that a ring R is a JB-ring provided that R/J(R) is a QB-ring, where J(R) is the Jacobson radical of R. In this paper, various necessary and sufficient conditions, under which a ring is a JB-ring, are established. It is proved that JB-rings can be characterized by pseudo-similarity. Furthermore, the author proves that R is a J B-ring iff so is R/J(R)2.

  8. APS storage ring vacuum system performance

    International Nuclear Information System (INIS)

    The Advanced Photon Source (APS) storage ring was designed to operated with 7-GeV, 100-mA positron beam with lifetimes > 20 hours. The lifetime is limited by residual gas scattering and Touschek scattering at this time. Photon-stimulated desorption and microwave power in the rf cavities are the main gas loads. Comparison of actual system gas loads and design calculations will be given. In addition, several special features of the storage ring vacuum system will be presented

  9. New dust belts of Uranus: one ring, two ring, red ring, blue ring.

    Science.gov (United States)

    de Pater, Imke; Hammel, Heidi B; Gibbard, Seran G; Showalter, Mark R

    2006-04-01

    We compared near-infrared observations of the recently discovered outer rings of Uranus with Hubble Space Telescope results. We find that the inner ring, R/2003 U 2, is red, whereas the outer ring, R/2003 U 1, is very blue. Blue is an unusual color for rings; Saturn's enigmatic E ring is the only other known example. By analogy to the E ring, R/2003 U 1 is probably produced by impacts into the embedded moon Mab, which apparently orbits at a location where nongravitational perturbations favor the survival and spreading of submicron-sized dust. R/2003 U 2 more closely resembles Saturn's G ring, which is red, a typical color for dusty rings. PMID:16601188

  10. Muon storage ring

    CERN Multimedia

    1974-01-01

    The muon storage ring where the g-2 of the muon is being measured with extremely high accuracy. The ring is 14-m in diameter and has very precise magnetic bending and electric focussing fields so that the muons orbit the ring under well-defined conditions.

  11. Rings Around Uranus

    Science.gov (United States)

    Maran, Stephen P.

    1977-01-01

    Events leading up to the discovery of the rings of Uranus are described. The methods used and the logic behind the methods are explained. Data collected to prove the existence of the rings are outlined and theories concerning the presence of planetary rings are presented. (AJ)

  12. Skew polynomial rings over abelian and idempotent reflexive rings

    OpenAIRE

    Louzari, Mohamed

    2015-01-01

    Let $R$ be a ring and $\\sigma$ an endomorphism of $R$. In this note, we study skew polynomial rings and skew power series rings over idempotent reflexive rings and abelian rings. Also, we introduce the concept of right (resp., left) $\\sigma$-idempotent reflexive rings which generalizes right (resp., left) idempotent reflexive rings and $\\sigma$-abelian rings. Certain results are obtained as corollaries from our results.

  13. Envelopes of Commutative Rings

    Institute of Scientific and Technical Information of China (English)

    Rafael PARRA; Manuel SAOR(I)N

    2012-01-01

    Given a significative class F of commutative rings,we study the precise conditions under which a commutative ring R has an F-envelope.A full answer is obtained when.F is the class of fields,semisimple commutative rings or integral domains.When F is the class of Noetherian rings,we give a full answer when the Krull dimension of R is zero and when the envelope is required to be epimorphic.The general problem is reduced to identifying the class of non-Noetherian rings having a monomorphic Noetherian envelope,which we conjecture is the empty class.

  14. APS storage ring vacuum system

    International Nuclear Information System (INIS)

    The Advanced Photon Source synchrotron radiation facility, under construction at the Argonne National Laboratory, incorporates a large ring for the storage of 7 GeV positrons for the generation of photon beams for the facility's experimental program. The Storage Ring's 1104 m circumference is divided into 40 functional sectors. The sectors include vacuum, beam transport, control, acceleration and insertion device components. The vacuum system, which is designed to operate at a pressure of 1 n Torr, consists of 240 connected sections, the majority of which are fabricated from an aluminum alloy extrusion. The sections are equipped with distributed NeG pumping, photon absorbers with lumped pumping, beam position monitors, vacuum diagnostics and valving. The details of the vacuum system design, selected results of the development program and general construction plans are presented. 11 refs., 6 figs., 3 tabs

  15. New Dust Belts of Uranus: One Ring, Two Ring, Red Ring, Blue Ring

    Energy Technology Data Exchange (ETDEWEB)

    de Pater, I; Hammel, H B; Gibbard, S G; Showalter, M R

    2006-02-02

    We compare near-infrared observations of the recently discovered outer rings of Uranus with HST results. We find that the inner ring, R/2003 U 2, is red, whereas the outer ring, R/2003 U 1, is very blue. Blue is an unusual color for rings; Saturn's enigmatic E ring is the only other known example. By analogy to the E ring, R/2003 U 1 is probably produced via impacts into the embedded moon Mab, which apparently orbits at a location where non-gravitational perturbations favor the survival and spreading of sub-micron sized dust. R/2003 U 2 more closely resembles Saturn's G ring.

  16. On Exchange QB∞-Rings

    Institute of Scientific and Technical Information of China (English)

    Huanyin Chen

    2007-01-01

    In this paper, we introduce a new class of rings, the QB∞-rings. We investigate necessary and sufficient conditions under which an exchange ring is a QB∞-ring. The modules over an exchange QB∞-ring are studied. Also, we prove that every regular square matrix over an exchange QB∞-ring admits a diagonal reduction by pseudo-invertible matrices.

  17. Research on the expanding deformation of ring radius in cold profiled ring rolling process

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Cold profiled ring rolling is an advanced local plastic deformation technology widely used to precisely manufacture various complex seamless ring parts.It plays an important role in many industrial fields such as aeronautics,astronautics,automobile,bearings,etc.In the cold ring rolling process,the ring radius expands gradually with the increase of the feeding amount(i.e.rolling reduction),and the expanding deformation of the ring radius is closely related to the rolling reduction.It is very important to investigate the expanding deformation of ring radius for the precise control of ring dimensions and the design of feeding movement.In this paper,the relation between the expanding deformation of the ring radius and the rolling reduction in the stepped ring rolling process,a typical profiled ring rolling process,is analyzed by using analytical method.The results show that the growth amount of the filling depth of groove can’t exceed the rolling reduction,that in the inner stepped ring rolling process,the curves of the outer radius and big inner radius with the rolling reduction are monotonous,ascending and concave,i.e.,the outer radius and big inner radius expand faster and faster with the increase of the rolling reduction,and that in the outer stepped ring rolling process,the curves of the inner radius and small outer radius with the rolling reduction are also monotonous,ascending and concave,i.e.,the inner radius and small outer radius expand faster and faster with the increase of the roll reduction.

  18. Token Ring Project

    Directory of Open Access Journals (Sweden)

    Adela Ionescu

    2007-01-01

    Full Text Available Ring topology is a simple configuration used to connect processes that communicate among themselves. A number of network standards such as token ring, token bus, and FDDI are based on the ring connectivity. This article will develop an implementation of a ring of processes that communicate among themselves via pipe links. The processes are nodes in the ring. Each process reads from its standard input and writes in its standard output. N-1 process redirects the its standard output to a standard input of the process through a pipe. When the ring-structure is designed, the project can be extended to simulate networks or to implement algorithms for mutual exclusion

  19. Token ring technology report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. This report provides an overview of the IBM Token-Ring technology and products built by IBM and compatible vendors. It consists of two sections: 1. A summary of the design trade-offs for the IBM Token-Ring. 2. A summary of the products of the major token-ring compatible vendors broken down by adapters and components, wiring systems, testing, and new chip technology.

  20. [Research advances in dendrochronology].

    Science.gov (United States)

    Fang, Ke-Yan; Chen, Qiu-Yan; Liu, Chang-Zhi; Cao, Chun-Fu; Chen, Ya-Jun; Zhou, Fei-Fei

    2014-07-01

    Tree-ring studies in China have achieved great advances since the 1990s, particularly for the dendroclimatological studies which have made some influence around the world. However, because of the uneven development, limited attention has been currently paid on the other branches of dendrochronology. We herein briefly compared the advances of dendrochronology in China and of the world and presented suggestions on future dendrochronological studies. Large-scale tree-ring based climate reconstructions in China are highly needed by employing mathematical methods and a high quality tree-ring network of the ring-width, density, stable isotope and wood anatomy. Tree-ring based field climate reconstructions provide potentials on explorations of climate forcings during the reconstructed periods via climate diagnosis and process simulation.

  1. On -Coherent Endomorphism Rings

    Indian Academy of Sciences (India)

    Li-Xin Mao

    2008-11-01

    A ring is called right -coherent if every principal right ideal is finitely presented. Let $M_R$ be a right -module. We study the -coherence of the endomorphism ring of $M_R$. It is shown that is a right -coherent ring if and only if every endomorphism of $M_R$ has a pseudokernel in add $M_R; S$ is a left -coherent ring if and only if every endomorphism of $M_R$ has a pseudocokernel in add $M_R$. Some applications are given.

  2. A Beautiful Ring

    Institute of Scientific and Technical Information of China (English)

    王对成

    2000-01-01

    Helen bought a very nice ring(戒指)and she wore it to the office the next day. Nobody saw her ring. She moved her hand this way and that, but still nobbdy in the offiee saw the ring on her finger. At tea time when they were sitting'round,she suddenly (突然地) stood up. “it is very hot here,”she said. “I think I'll take off my ring.”

  3. Homorooty in Rings

    Directory of Open Access Journals (Sweden)

    M. H. Hooshmand

    2010-03-01

    Full Text Available The topic of ”Homorooty” (for integer numbers has been introduced and studied in [2]. There are some applications of the homorooty in studying and solving some Diophantine equations and systems, as an interesting and useful elementary method. As a continuation of the Homorooty, we consider it for arbitrary rings and will study its properties in different rings, especially UFD and homorooty rings (which will be introduced. At last we shall state some applications of homorooty in studying some equations over homorooty rings

  4. Beam Measurements in Storage Rings

    Science.gov (United States)

    Hofmann, Albert

    1996-05-01

    Beam measurements in storage rings are made to diagnose performance limitations and to gain knowledge of the beam behavior in view of improvements and to the benefit for other machines. In beam optics the measurement of the orbit or the trajectory with beam position monitors distributed around the ring reveals deflection errors. The overall focusing is checked by measuring the betatron frequency (tune) using a pulse or continuous excitation of the oscillation. Observing this oscillation with all the beam position monitors around the ring the beta function and the betatron phase advance are obtained. This measurement done for different momenta, i.e. RF-frequencies, gives the local chromaticity and its correction. The tune dependence on quadrupole strength gives the value of the local beta function. Synchrotron radiation is a powerful diagnostics tool and can give the beam cross section. Beam instabilities are investigated with similar methods. The growth or damping rates and frequencies of betatron and synchrotron oscillations, observed as a function of intensity, give a convolution of the resistive and reactive part of the transverse and longitudinal impedance with the spectrum of the oscillation mode. Coupled bunch instabilities are caused by narrow band impedances at particular frequencies while single traversal effects, including energy loss and bunch lengthening, are due to a broad band impedance. A model of the impedance can be constructed from such measurements done with different bunch lengths, tunes and other parameters. In some cases the element causing an instability can be identified. The dependence of the orbit and phase advance around the ring on intensity can give the location of impedances. To probe the impedance at very high frequencies the effects on very short bunches or the energy loss of a continuous beam due to its Schottky noise are measured. The beam energy, usually known from magnetic measurements, can be obtained directly with high

  5. Ring Around a Galaxy

    Science.gov (United States)

    1999-01-01

    Space Telescope Science Institute astronomers are giving the public chances to decide where to aim NASA's Hubble Space Telescope. Guided by 8,000 Internet voters, Hubble has already been used to take a close-up, multi-color picture of the most popular object from a list of candidates, the extraordinary 'polar-ring' galaxy NGC 4650A. Located about 130 million light-years away, NGC 4650A is one of only 100 known polar-ring galaxies. Their unusual disk-ring structure is not yet understood fully. One possibility is that polar rings are the remnants of colossal collisions between two galaxies sometime in the distant past, probably at least 1 billion years ago. What is left of one galaxy has become the rotating inner disk of old red stars in the center. Meanwhile, another smaller galaxy which ventured too close was probably severely damaged or destroyed. The bright bluish clumps, which are especially prominent in the outer parts of the ring, are regions containing luminous young stars, examples of stellar rebirth from the remnants of an ancient galactic disaster. The polar ring appears to be highly distorted. No regular spiral pattern stands out in the main part of the ring, and the presence of young stars below the main ring on one side and above on the other shows that the ring is warped and does not lie in one plane. Determining the typical ages of the stars in the polar ring is an initial goal of our Polar Ring Science Team that can provide a clue to the evolution of this unusual galaxy. The HST exposures were acquired by the Hubble Heritage Team, consisting of Keith Noll, Howard Bond, Carol Christian, Jayanne English, Lisa Frattare, Forrest Hamilton, Anne Kinney and Zolt Levay, and guest collaborators Jay Gallagher (University of Wisconsin-Madison), Lynn Matthews (National Radio Astronomy Observatory-Charlottesville), and Linda Sparke (University of Wisconsin-Madison).

  6. Revocable Ring Signature

    Institute of Scientific and Technical Information of China (English)

    Dennis Y. W. Liu; Joseph K. Liu; Yi Mu; Willy Susilo; Duncan S. Wong

    2007-01-01

    Group signature allows the anonymity of a real signer in a group to be revoked by a trusted party called group manager. It also gives the group manager the absolute power of controlling the formation of the group. Ring signature, on the other hand, does not allow anyone to revoke the signer anonymity, while allowing the real signer to forma group (also known as a ring) arbitrarily without being controlled by any other party. In this paper, we propose a new variant for ring signature, called Revocable Ring Signature. The signature allows a real signer to form a ring arbitrarily while allowing a set of authorities to revoke the anonymity of the real signer. This new variant inherits the desirable properties from both group signature and ring signature in such a way that the real signer will be responsible for what it has signed as the anonymity is revocable by authorities while the real signer still has the freedom on ring formation. We provide a formal security model for revocable ring signature and propose an efficient construction which is proven secure under our security model.

  7. EBT ring physics

    International Nuclear Information System (INIS)

    This workshop attempted to evaluate the status of the current experimental and theoretical understanding of hot electron ring properties. The dominant physical processes that influence ring formation, scaling, and their optimal behavior are also studied. Separate abstracts were prepared for each of the 27 included papers

  8. Jupiter's Rings: Sharpest View

    Science.gov (United States)

    2007-01-01

    The New Horizons spacecraft took the best images of Jupiter's charcoal-black rings as it approached and then looked back at Jupiter. The top image was taken on approach, showing three well-defined lanes of gravel- to boulder-sized material composing the bulk of the rings, as well as lesser amounts of material between the rings. New Horizons snapped the lower image after it had passed Jupiter on February 28, 2007, and looked back in a direction toward the sun. The image is sharply focused, though it appears fuzzy due to the cloud of dust-sized particles enveloping the rings. The dust is brightly illuminated in the same way the dust on a dirty windshield lights up when you drive toward a 'low' sun. The narrow rings are confined in their orbits by small 'shepherding' moons.

  9. The Enceladus Ring

    Science.gov (United States)

    2006-01-01

    [figure removed for brevity, see original site] The Enceladus Ring (labeled) This excellent view of the faint E ring -- a ring feature now known to be created by Enceladus -- also shows two of Saturn's small moons that orbit within the ring, among a field of stars in the background. The E ring extends from three to eight Saturn radii -- about 180,000 kilometers (118,000 miles) to 482,000 kilometers (300,000 miles). Its full extent is not visible in this view. Calypso (22 kilometers, or 14 miles across) and Helene (32 kilometers, or 20 miles across) orbit within the E ring's expanse. Helene skirts the outer parts of the E ring, but here it is projected in front of a region deeper within the ring. Calypso and Helene are trojan satellites, or moons that orbit 60 degrees in front or behind a larger moon. Calypso is a Tethys trojan and Helene is a trojan of Dione. An interesting feature of note in this image is the double-banded appearance of the E-ring, which is created because the ring is somewhat fainter in the ringplane than it is 500-1,000 kilometers (300-600 miles) above and below the ringplane. This appearance implies that the particles in this part of the ring have nonzero inclinations (a similar affect is seen in Jupiter's gossamer ring). An object with a nonzero inclination does not orbit exactly at Saturn's ringplane. Instead, its orbit takes it above and below the ringplane. Scientists are not entirely sure why the particles should have such inclinations, but they are fairly certain that the reason involves Enceladus. One possible explanation is that all the E ring particles come from the plume of icy material that is shooting due south out of the moon's pole. This means all of the particles are created with a certain velocity out of the ringplane, and then they orbit above and below that plane. Another possible explanation is that Enceladus produces particles with a range of speeds, but the moon gravitationally scatters any particles that lie very close to

  10. Dynamics of the Uranian Rings

    Science.gov (United States)

    Dermott, S. F.

    1984-01-01

    Some of the problems of the shepherding satellite model of Goldreich ant tremaine are discussed. The following topics are studied: (1) optical depths of the all the observed narrow rings; (2) satellite and ring separation timescales; (3) ring edge sharpness; (4) shock formation in narrow rings; (5) the existence of small satellites near the Uranian rings; and (6) the apse and node alignments of the eccentric and inclined rings.

  11. Ring chromosome 13

    DEFF Research Database (Denmark)

    Brandt, C A; Hertz, Jens Michael; Petersen, M B;

    1992-01-01

    A stillborn male child with anencephaly and multiple malformations was found to have the karyotype 46,XY,r(13) (p11q21.1). The breakpoint at 13q21.1, determined by high resolution banding, is the most proximal breakpoint ever reported in patients with ring chromosome 13. In situ hybridisation...... with the probe L1.26 confirmed the derivation from chromosome 13 and DNA polymorphism analysis showed maternal origin of the ring chromosome. Our results, together with a review of previous reports of cases with ring chromosome 13 with identified breakpoints, could neither support the theory of distinct clinical...

  12. Group ring cryptography

    CERN Document Server

    Hurley, Barry

    2011-01-01

    Cryptographic systems are derived using units in group rings. Combinations of types of units in group rings give units not of any particular type. This includes cases of taking powers of units and products of such powers and adds the complexity of the {\\em discrete logarithm} problem to the system. The method enables encryption and (error-correcting) coding to be combined within one system. These group ring cryptographic systems may be combined in a neat way with existing cryptographic systems, such as RSA, and a combination has the combined strength of both systems. Examples are given.

  13. Ringed 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) of the five subspecies of ringed seals (Phoca hispida). It was produced...

  14. Remotely operated locking ring

    International Nuclear Information System (INIS)

    A ring for fastening tubes with conical ends with only one manipulator is described. It is opened by compression of a spring with the manipulator grip, placed on the tubes to fasten, closed by releasing the pressure and locked

  15. The g-2 ring

    CERN Multimedia

    1974-01-01

    The precise measurement of "g-2", the anomalous magnetic moment of the muon, required a special muon storage ring with electrostatic focussing and very accurate knowledge of the magnetic bending field. For more details see under photo 7405430.

  16. Child sex rings.

    OpenAIRE

    Wild, N J; Wynne, J M

    1986-01-01

    Details of 11 child sex rings identified in one working class community were obtained by interviewing investigating police officers and examining health and social services records. The rings contained 14 adult male perpetrators and 175 children aged 6-15 years. Most perpetrators used child ringleaders to recruit victims; others became a "family friend" or obtained a position of authority over children. Secrecy was encouraged and bribery, threats, and peer pressure used to induce participatio...

  17. Ringed accretion disks: equilibrium configurations

    CERN Document Server

    Pugliese, D

    2015-01-01

    We investigate a model of ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the General Relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can be then determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We pr...

  18. Saturn's Other Ring Current

    Science.gov (United States)

    Crary, F. J.

    2014-04-01

    Saturn's main rings orbit the planet within an atmosphere and ionosphere of water, oxygen and hydrogen, produced by meteoritic impacts on and ultraviolet photodesorbtion of the ring particles [Johnson et al., 2006; Luhmann et al., 2006; Tseng et al., 2010]. The neutral atmosphere itself has only been tentatively detected through ultraviolet fluorescents of OH [Hall et al., 1996] while the ionosphere was observed in situ by the Cassini spacecraft shortly after orbital insertion [Coates et al.,2005; Tokar et al. 2005, Waite et al. 2005]. Although the plasma flow velocity of this ionosphere is not well-constrained, but the close association with the rings suggests that its speed would be couppled to the keplarian velocity of the rings themselves. As a result, the motion of the plasma through Saturn's magnetic field would produce an induced voltage, oriented away from the planet outside synchronous orbit and towards the planet inside synchronous orbit. Such a potential could result in currents flowing across the ring plane and closeing along magnetic field lines and through Saturn's ionosphere at latitudes between 36o and 48o. Cassini observations of whistler-mode plasma wave emissions [Xin et al.,2006] centered on synchronous orbit (1.76 Rs, mapping to 41o latitude) have been interpreted as a product of field-aligned electron beams associated with such a current. This presentation will investigate the magnitude of these currents and the resulting Joule heating of the ionosphere. An important constraint is that no auroral ultraviolet emissions have been observed at the relevant latitudes. In contrast, Joule heating could affect infrared emissions from H3+. Variations in H3+ emission associated with Saturn's rings have been reported by O'Donoghue et al., 2013, and interpreted as a result of ring "rain", i.e. precipitating water group species from the rings which alter ionosphereic chemistry and H3+ densities. As noted by O'Donoghue et al., this interpretation may be

  19. The LSU Electron Storage Ring, the first commercially-built storage ring

    International Nuclear Information System (INIS)

    The Brobeck Division of Maxwell Laboratories, Inc., is building the first industrially-produced storage ring. It will be located at Louisiana State University (LSU) at the Center for Advanced Microstructures and Devices (CAMD) in Baton Rouge. The purpose of this electron storage ring is to provide intense beams of x-rays to advance the state-of-the-art in lithography and to permit research in a broad area. This facility consists of a 1.2 GeV, 400 mA electron storage ring with a 200 MeV linac injector. The magnet lattice is a Chasman-Green design (double-bend achromat), and the ring circumference is 55.2 meters. There are four 3.0 meter, dispersion-free straight sections, one for injection, one for the 500 MHz RF cavity, and two for possible future insertion devices. The storge ring construction project is in the detailed-design stage, and many systems are in the initial stages of fabrication. 4 figs., 1 tab

  20. Physics of planetary rings

    Science.gov (United States)

    Gorkavyi, N.

    2007-08-01

    It is difficult to enumerate all the surprises presented by the planetary rings. The Saturnian rings are stratified into thousands of ringlets and the Uranian rings are compressed into narrow streams, which for some reason or other differ from circular orbits like the wheel of an old bicycle. The edge of the rings is jagged and the rings themselves are pegged down under the gravitational pressure of the satellites, bending like a ship's wake. There are spiral waves, elliptical rings, strange interlacing of narrow ringlets, and to cap it all one has observed in the Neptunian ring system three dense, bright arcs - like bunches of sausages on a transparent string. For celestial mechanics this is a spectacle as unnatural as a bear's tooth in the necklace of the English queen. In the dynamics of planetary rings the physics of collective interaction was supplemented by taking collisions between particles into account. One was led to study a kinetic equation with a rather complex collision integral - because the collisions are inelastic - which later on made it possible, both by using the Chapman-Enskog method and by using the solution of the kinetic equation for a plasma in a magnetic field, to reduce it to a closed set of (hydrodynamical) moment equations [1]. The hydrodynamical instabilities lead to the growth of short-wavelength waves and large-scale structures of the Saturnian rings [1]. We have shown that the formation of the existing dense Uranian rings is connected with the capture of positively drifting ring particles in inner Lindblad resonances which arrest this drift [1]. After the formation of dense rings at the positions of satellite resonances the collective interaction between resonant particles is amplified and the rings can leave the resonance and drift away from the planet and the parent resonance. We can expect in the C ring an appreciable positive ballistic particle drift caused by the erosion of the B ring by micrometeorites. It is therefore natural

  1. Rings dominate western Gulf

    Science.gov (United States)

    Vidal L., Francisco V.; Vidal L., Victor M. V.; Molero, José María Pérez

    Surface and deep circulation of the central and western Gulf of Mexico is controlled by interactions of rings of water pinched from the gulf's Loop Current. The discovery was made by Mexican oceanographers who are preparing a full-color, 8-volume oceanographic atlas of the gulf.Anticyclonic warm-core rings pinch off the Loop Current at a rate of about one to two per year, the scientists of the Grupo de Estudios Oceanográficos of the Instituto de Investigaciones Eléctricas (GEO-IIE) found. The rings migrate west until they collide with the continental shelf break of the western gulf, almost always between 22° and 23°N latitude. On their westward travel they transfer angular momentum and vorticity to the surrounding water, generating cyclonic circulations and vortex pairs that completely dominate the entire surface and deep circulation of the central and western gulf.

  2. Oligomeric ferrocene rings

    Science.gov (United States)

    Inkpen, Michael S.; Scheerer, Stefan; Linseis, Michael; White, Andrew J. P.; Winter, Rainer F.; Albrecht, Tim; Long, Nicholas J.

    2016-09-01

    Cyclic oligomers comprising strongly interacting redox-active monomer units represent an unknown, yet highly desirable class of nanoscale materials. Here we describe the synthesis and properties of the first family of molecules belonging to this compound category—differently sized rings comprising only 1,1‧-disubstituted ferrocene units (cyclo[n], n = 5–7, 9). Due to the close proximity and connectivity of centres (covalent Cp–Cp linkages; Cp = cyclopentadienyl) solution voltammograms exhibit well-resolved, separated 1e– waves. Theoretical interrogations into correlations based on ring size and charge state are facilitated using values of the equilibrium potentials of these transitions, as well as their relative spacing. As the interaction free energies between the redox centres scale linearly with overall ring charge and in conjunction with fast intramolecular electron transfer (∼107 s‑1), these molecules can be considered as uniformly charged nanorings (diameter ∼1–2 nm).

  3. Decay ring design

    CERN Document Server

    Chancé, A; Bouquerel, E; Hancock, S; Jensen, E

    The study of the neutrino oscillation between its different flavours needs pureand very intense fluxes of high energy, well collimated neutrinos with a welldetermined energy spectrum. A dedicated machine seems to be necessarynowadays to reach the required flux. A new concept based on the β-decayof radioactive ions which were accelerated in an accelerator chain was thenproposed. After ion production, stripping, bunching and acceleration, the unstableions are then stored in a racetrack-shaped superconducting decay ring.Finally, the ions are accumulated in the decay ring until being lost. The incomingbeam is merged to the stored beam by using a specific RF system, whichwill be presented here.We propose here to study some aspects of the decay ring, such as its opticalproperties, its RF system or the management of the losses which occur in thering (mainly by decay or by collimation).

  4. On Simple Noetherian Rings

    Institute of Scientific and Technical Information of China (English)

    Somyot Plubtieng

    2003-01-01

    A module M is called a CS-module (or extending module [5]) if every submodule of M is essential in a direct summand of M. It is shown that (i) a simple ring R is right noetherian if and only if every cyclic singular right R-module is either a CS-module or a noetherian module; (ii) for a prime ring R, if every proper cyclic right R-module is a direct sum of a quasi-injective module and a finitely cogenerated module, then R is either semisimple artinian or a right Ore domain; and (iii) a prime ring R is right noetherian if and only if every cyclic right R-module is a direct sum of a quasi-injective module and a noetherian module.

  5. Tunneling Through Black Rings

    Institute of Scientific and Technical Information of China (English)

    ZHAO Liu

    2007-01-01

    Hawking radiation of black ring solutions to 5-dimensional Einstein-Maxwell-dilaton theory is analyzed by use of the Parikh-Wilczek tunneling method. To get the correct tunneling amplitude and emission rate, we adopt and develop the Angheben-Nadalini-Vanzo-Zerbini covariant approach to cover the effects of rotation and electronic discharge all at once, and the effect of back reaction is also taken into account. This constitutes a unified approach to the tunneling problem. Provided the first law of thermodynamics for black rings holds, the emission rate is proportional to the exponential of the change of Bekenstein-Hawking entropy. Explicit calculation for black ring temperatures agrees exactly with the results obtained via the classical surface gravity method and the quasi-local formalism.

  6. Autocatalytic chemical smoke rings

    CERN Document Server

    Rogers, M C; Rogers, Michael C.; Morris, Stephen W.

    2005-01-01

    Buoyant plumes, evolving free of boundary constraints, may develop well-defined mushroom shaped heads. In normal plumes, overturning flow in the head entrains less buoyant fluid from the surroundings as the head rises, robbing the plume of its driving force. We consider here a new type of plume in which the source of buoyancy is an autocatalytic chemical reaction. The reaction occurs at a sharp front which separates reactants from less dense products. In this type of plume, entrainment assists the reaction, producing new buoyancy which fuels an accelerating plume head. When the head has grown to a critical size, it detaches from the upwelling conduit, forming an accelerating, buoyant vortex ring. This vortex is analogous to a rising smoke ring. A second-generation head then develops at the point of detachment.Multiple generations of chemical vortex rings can detach from a single triggering event.

  7. Den mindst ringe verdensorden

    DEFF Research Database (Denmark)

    Hansen, Birthe

    2015-01-01

    I 25 år har USA's styrkeposition og politik forsynet os med en 'verdensorden', der i et historisk perspektiv fremstår som den mindst ringe: fravær af store krige, mere demokrati, økonomisk fremgang - men dog også sammenbrudte stater og terrorisme.......I 25 år har USA's styrkeposition og politik forsynet os med en 'verdensorden', der i et historisk perspektiv fremstår som den mindst ringe: fravær af store krige, mere demokrati, økonomisk fremgang - men dog også sammenbrudte stater og terrorisme....

  8. On toric face rings

    OpenAIRE

    Ichim, Bogdan; Roemer, Tim

    2006-01-01

    Following a construction of Stanley we consider toric face rings associated to rational pointed fans. This class of rings is a common generalization of the concepts of Stanley--Reisner and affine monoid algebras. The main goal of this article is to unify parts of the theories of Stanley--Reisner- and affine monoid algebras. We consider (non-pure) shellable fan's and the Cohen--Macaulay property. Moreover, we study the local cohomology, the canonical module and the Gorenstein property of a tor...

  9. Ringed accretion disks: instabilities

    CERN Document Server

    Pugliese, D

    2016-01-01

    We analyze the possibility that several instability points may be formed, due to the Paczy\\'nski mechanism of violation of mechanical equilibrium, in the orbiting matter around a supermassive Kerr black hole. We consider recently proposed model of ringed accretion disk, made up by several tori (rings) which can be corotating or counterrotating relative to the Kerr attractor due to the history of the accretion process. Each torus is governed by the general relativistic hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. We prove that the number of the instability points is generally limited and depends on the dimensionless spin of the rotating attractor.

  10. Unidirectional ring lasers

    Science.gov (United States)

    Hohimer, J.P.; Craft, D.C.

    1994-09-20

    Unidirectional ring lasers formed by integrating nonreciprocal optical elements into the resonant ring cavity is disclosed. These optical elements either attenuate light traveling in a nonpreferred direction or amplify light traveling in a preferred direction. In one preferred embodiment the resonant cavity takes the form of a circle with an S-shaped crossover waveguide connected to two points on the interior of the cavity such that light traveling in a nonpreferred direction is diverted from the cavity into the crossover waveguide and reinjected out of the other end of the crossover waveguide into the cavity as light traveling in the preferred direction. 21 figs.

  11. The covariant chiral ring

    Science.gov (United States)

    Bourget, Antoine; Troost, Jan

    2016-03-01

    We construct a covariant generating function for the spectrum of chiral primaries of symmetric orbifold conformal field theories with N = (4 , 4) supersymmetry in two dimensions. For seed target spaces K3 and T 4, the generating functions capture the SO(21) and SO(5) representation theoretic content of the chiral ring respectively. Via string dualities, we relate the transformation properties of the chiral ring under these isometries of the moduli space to the Lorentz covariance of perturbative string partition functions in flat space.

  12. The Covariant Chiral Ring

    CERN Document Server

    Bourget, Antoine

    2015-01-01

    We construct a covariant generating function for the spectrum of chiral primaries of symmetric orbifold conformal field theories with N=(4,4) supersymmetry in two dimensions. For seed target spaces K3 and T4, the generating functions capture the SO(21) and SO(5) representation theoretic content of the chiral ring respectively. Via string dualities, we relate the transformation properties of the chiral ring under these isometries of the moduli space to the Lorentz covariance of perturbative string partition functions in flat space.

  13. Electrothermal Ring Burn

    OpenAIRE

    Yakup Çil; Hamza Yıldız; Özlem Karabudak Abuaf

    2012-01-01

    Low-voltage fountainheads such as car, tractor or motorcycle batteries are predisposed to produce large currents. Any metal object that comes into contact with these batteries may result in short-circuit. This may result in rapid and excessive heating of metal object and an electrothermal burn. Herein we presented a motorcycle driver who was 28-year-old man with electrothermal ring burn which was caused by metal chain that was used as a ring. (Turk J Dermatol 2012; 6: 106-7)

  14. Electrothermal Ring Burn

    Directory of Open Access Journals (Sweden)

    Yakup Çil

    2012-09-01

    Full Text Available Low-voltage fountainheads such as car, tractor or motorcycle batteries are predisposed to produce large currents. Any metal object that comes into contact with these batteries may result in short-circuit. This may result in rapid and excessive heating of metal object and an electrothermal burn. Herein we presented a motorcycle driver who was 28-year-old man with electrothermal ring burn which was caused by metal chain that was used as a ring. (Turk J Dermatol 2012; 6: 106-7

  15. Flushing Ring for EDM

    Science.gov (United States)

    Earwood, L.

    1985-01-01

    Removing debris more quickly lowers cutting time. Operation, cutting oil and pressurized air supplied to ring placed around workpiece. Air forces oil through small holes and agitates oil as it flows over workpiece. High flow rate and agitation dislodge and remove debris. Electrical discharge removes material from workpiece faster.

  16. Fusion Rings for Quantum Groups

    DEFF Research Database (Denmark)

    Andersen, Henning Haahr; Stroppel, Catharina

    2012-01-01

    We study the fusion rings of tilting modules for a quantum group at a root of unity modulo the tensor ideal of negligible tilting modules. We identify them in type A with the combinatorial rings from [12] and give a similar description of the sp2n-fusion ring in terms of noncommutative symmetric...... functions. Moreover we give a presentation of all fusion rings in classical types as quotients of polynomial rings. Finally we also compute the fu- sion rings for type G2....

  17. Fusion rings and fusion ideals

    DEFF Research Database (Denmark)

    Andersen, Troels Bak

    This dissertation investigates fusion rings, which are Grothendieck groups of rigid, monoidal, semisimple, abelian categories. Special interest is in rational fusion rings, i.e., fusion rings which admit a finite basis, for as commutative rings they may be presented as quotients of polynomial rings...... by the so-called fusion ideals. The fusion rings of Wess-Zumino-Witten models have been widely studied and are well understood in terms of precise combinatorial descriptions and explicit generating sets of the fusion ideals. They also appear in another, more general, setting via tilting modules for quantum...

  18. Rings from Close Encounters

    Science.gov (United States)

    Kohler, Susanna

    2016-09-01

    Weve recently discovered narrow sets of rings around two minor planets orbiting in our solar system. How did these rings form? A new study shows that they could be a result of close encounters between the minor planets and giants like Jupiter or Neptune.Unexpected Ring SystemsPositions of the centaurs in our solar system (green). Giant planets (red), Jupiter trojans (grey), scattered disk objects (tan) and Kuiper belt objects (blue) are also shown. [WilyD]Centaurs are minor planets in our solar system that orbit between Jupiter and Neptune. These bodies of which there are roughly 44,000 with diameters larger than 1 km have dynamically unstable orbits that cross paths with those of one or more giant planets.Recent occultation observations of two centaurs, 10199 Chariklo and 2060 Chiron, revealed that these bodies both host narrow ring systems. Besides our four giant planets, Chariklo and Chiron are the only other bodies in the solar system known to have rings. But how did these rings form?Scientists have proposed several models, implicating collisions, disruption of a primordial satellite, or dusty outgassing. But a team of scientists led by Ryuki Hyodo (Paris Institute of Earth Physics, Kobe University) has recently proposed an alternative scenario: what if the rings were formed from partial disruption of the centaur itself, after it crossed just a little too close to a giant planet?Tidal Forces from a GiantHyodo and collaborators first used past studies of centaur orbits to estimate that roughly 10% of centaurs experience close encounters (passing within a distance of ~2x the planetary radius) with a giant planet during their million-year lifetime. The team then performed a series of simulations of close encounters between a giant planet and a differentiated centaur a body in which the rocky material has sunk to form a dense silicate core, surrounded by an icy mantle.Some snapshots of simulation outcomes (click for a closer look!) for different initial states of

  19. Thermal analysis of the beam missteering in APS storage ring

    International Nuclear Information System (INIS)

    Several bending magnet beam missteering cases have been investigated for the 7-GeV storage ring of the Advanced Photon Source (APS). One of the critical missteering events is presented in this paper. Finite element analyses are performed to solve for both temperature and stress fields. Thermally induced deflections are determined by using beam bending theory. A safe current limit is established for the storage ring chambers

  20. e-læring

    DEFF Research Database (Denmark)

    Helms, Niels Henrik

    e-læring kan defineres på ganske mange måder. Ordet e-læring består jo tydeligt nok af to elementer. E + læring ligesom e-handel eller e-banking, og umiddelbart vil de fleste nok sige, at det så handler om læring vha. internettet. I bidraget advokeres for en læringsmæssig frem for normativ tilgang....

  1. The Black Ring is Unstable

    CERN Document Server

    Santos, Jorge E

    2015-01-01

    We study non-axisymmetric linearised gravitational perturbations of the Emparan-Reall black ring using numerical methods. We find an unstable mode whose onset lies within the "fat" branch of the black ring and continues into the "thin" branch. Together with previous results using Penrose inequalities that fat black rings are unstable, this provides numerical evidence that the entire black ring family is unstable.

  2. RINGED ACCRETION DISKS: EQUILIBRIUM CONFIGURATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Pugliese, D.; Stuchlík, Z., E-mail: d.pugliese.physics@gmail.com, E-mail: zdenek.stuchlik@physics.cz [Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo náměstí 13, CZ-74601 Opava (Czech Republic)

    2015-12-15

    We investigate a model of a ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the general relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can then be determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We present also a perturbation analysis based on evolution of the oscillating components of the ringed disk. The dynamics of the unstable phases of the ringed disk evolution seems to be promising in relation to high-energy phenomena demonstrated in active galactic nuclei.

  3. DC-Powered Jumping Ring

    Science.gov (United States)

    Jeffery, Rondo N.; Farhang, Amiri

    2016-01-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant…

  4. Fusion Rings for Quantum Groups

    DEFF Research Database (Denmark)

    Andersen, Henning Haahr; Stroppel, Catharina

    2014-01-01

    We study the fusion rings of tilting modules for a quantum group at a root of unity modulo the tensor ideal of negligible tilting modules. We identify them in type A with the combinatorial rings from Korff, C., Stroppel, C.: The sl(ˆn)k-WZNW fusion ring: a combinato-rial construction and a realis...

  5. Torsion units in group rings

    OpenAIRE

    Bist, Vikas

    1992-01-01

    Let U(RG) be the unit group of the group ring RG. In this paper we study group rings RG whose support elements of every torsion unit are torsion, where R is either the ring of integers Z or a field K.

  6. Hexagonal graphene onion rings.

    Science.gov (United States)

    Yan, Zheng; Liu, Yuanyue; Lin, Jian; Peng, Zhiwei; Wang, Gunuk; Pembroke, Elvira; Zhou, Haiqing; Xiang, Changsheng; Raji, Abdul-Rahman O; Samuel, Errol L G; Yu, Ting; Yakobson, Boris I; Tour, James M

    2013-07-24

    Precise spatial control of materials is the key capability of engineering their optical, electronic, and mechanical properties. However, growth of graphene on Cu was revealed to be seed-induced two-dimensional (2D) growth, limiting the synthesis of complex graphene spatial structures. In this research, we report the growth of onion ring like three-dimensional (3D) graphene structures, which are comprised of concentric one-dimensional hexagonal graphene ribbon rings grown under 2D single-crystal monolayer graphene domains. The ring formation arises from the hydrogenation-induced edge nucleation and 3D growth of a new graphene layer on the edge and under the previous one, as supported by first principles calculations. This work reveals a new graphene-nucleation mechanism and could also offer impetus for the design of new 3D spatial structures of graphene or other 2D layered materials. Additionally, in this research, two special features of this new 3D graphene structure were demonstrated, including nanoribbon fabrication and potential use in lithium storage upon scaling. PMID:23815279

  7. APS storage ring vacuum system development

    International Nuclear Information System (INIS)

    The Advanced Photon Source synchrotron radiation facility, under construction at the Argonne National Laboratory, incorporates a large ring for the storage of 7 GeV positrons for the generation of photon beams for the facility's materials research program. The Storage Ring's 1104 m circumference is divided into 40 sectors which contain vacuum, beam transport, control, rf and insertion device systems. The vacuum system will operate at a pressure of 1 nTorr and is fabricated from aluminum. The system includes distributed NeG pumping, photon absorbers with lumped pumping, beam position monitors, vacuum diagnostics and valving. An overview of the vacuum system design and details of selected development program results are presented. 5 refs

  8. Magnetic fields in ring galaxies

    CERN Document Server

    Moss, D; Silchenko, O; Sokoloff, D; Horellou, C; Beck, R

    2016-01-01

    Many galaxies contain magnetic fields supported by galactic dynamo action. However, nothing definitive is known about magnetic fields in ring galaxies. Here we investigate large-scale magnetic fields in a previously unexplored context, namely ring galaxies, and concentrate our efforts on the structures that appear most promising for galactic dynamo action, i.e. outer star-forming rings in visually unbarred galaxies. We use tested methods for modelling $\\alpha-\\Omega$ galactic dynamos, taking into account the available observational information concerning ionized interstellar matter in ring galaxies. Our main result is that dynamo drivers in ring galaxies are strong enough to excite large-scale magnetic fields in the ring galaxies studied. The variety of dynamo driven magnetic configurations in ring galaxies obtained in our modelling is much richer than that found in classical spiral galaxies. In particular, various long-lived transients are possible. An especially interesting case is that of NGC 4513 where th...

  9. The Rings Characterized by Minimal Left Ideals

    Institute of Scientific and Technical Information of China (English)

    Jun Chao WEI

    2005-01-01

    We study these rings with every minimal left ideal being a projective, direct summand and a p-injective module, respectively. Some characterizations of these rings are given, and the relations among them are obtained. With these rings, we characterize semisimple rings. Finally, we introduce MC2 rings, and give some characterizations of MC2 rings.

  10. Rings Research in the Next Decade

    Science.gov (United States)

    Burns, J. A.; Tiscareno, M. S.

    2009-12-01

    The study of planetary ring systems forms a key component of planetary science for several reasons: 1) The evolution and current states of planets and their satellites are affected in many ways by rings, while 2) conversely, properties of planets and moons and other solar system populations are revealed by their effects on rings; 3) highly structured and apparently delicate ring systems may be bellwethers, constraining various theories of the origin and evolution of their entire planetary system; and finally, 4) planetary rings provide an easily observable analogue to other astrophysical disk systems, enabling real “ground truth” results applicable to disks much more remote in space and/or time, including proto-planetary disks, circum-stellar disks, and even galaxies. Significant advances have been made in rings science in the past decade. The highest-priority rings research recommendations of the last Planetary Science Decadal Survey were to operate and extend the Cassini orbiter mission at Saturn; this has been done with tremendous success, accounting for much of the progress made on key science questions, as we will describe. Important progress in understanding the rings of Saturn and other planets has also come from Earth-based observational and theoretical work, again as prioritized by the last Decadal Survey. However, much important work remains to be done. At Saturn, the Cassini Solstice Mission must be brought to a successful completion. Priority should also be placed on sending spacecraft to Neptune and/or Uranus, now unvisited for more than 20 years. At Jupiter and Pluto, opportunities afforded by visiting spacecraft capable of studying rings should be exploited. On Earth, the need for continued research and analysis remains strong, including in-depth analysis of rings data already obtained, numerical and theoretical modeling work, laboratory analysis of materials and processes analogous to those found in the outer solar system, and continued Earth

  11. Continuous ring furnaces

    Energy Technology Data Exchange (ETDEWEB)

    De Stefani, G.; Genevois, J.L.; Paolo, P.

    1981-01-06

    A smoke conducting apparatus for use particularly with continuous ring furnaces (e.g., Hoffman furnaces) wherein each furnace chamber is connected to the smoke channel, the latter being a metal pipe inclined slightly from horizontal and provided with one or more traps along the length of its bottom surface, each trap containing a removable receptacle, and heating means being disposed along the bottom of the channel to fluidize tarry deposits of combustion products so that such deposits will flow by gravity into the removable receptacle.

  12. Viscosity of ring polymer melts

    KAUST Repository

    Pasquino, Rossana

    2013-10-15

    We have measured the linear rheology of critically purified ring polyisoprenes, polystyrenes, and polyethyleneoxides of different molar masses. The ratio of the zero-shear viscosities of linear polymer melts η0,linear to their ring counterparts η0,ring at isofrictional conditions is discussed as a function of the number of entanglements Z. In the unentangled regime η0,linear/η 0,ring is virtually constant, consistent with the earlier data, atomistic simulations, and the theoretical expectation η0,linear/ η0,ring = 2. In the entanglement regime, the Z-dependence of ring viscosity is much weaker than that of linear polymers, in qualitative agreement with predictions from scaling theory and simulations. The power-law extracted from the available experimental data in the rather limited range 1 < Z < 20, η0,linear/η0,ring ∼ Z 1.2±0.3, is weaker than the scaling prediction (η0,linear/η0,ring ∼ Z 1.6±0.3) and the simulations (η0,linear/ η0,ring ∼ Z2.0±0.3). Nevertheless, the present collection of state-of-the-art experimental data unambiguously demonstrates that rings exhibit a universal trend clearly departing from that of their linear counterparts, and hence it represents a major step toward resolving a 30-year-old problem. © 2013 American Chemical Society.

  13. Physics issues in diffraction limited storage ring design

    Institute of Scientific and Technical Information of China (English)

    FAN Wei; BAI ZhengHe; GAO WeiWei; FENG GuangYao; LI WeiMin; WANG Lin; HE DuoHui

    2012-01-01

    Diffraction limited electron storage ring is considered a promising candidate for future light sources,whose main characteristics are higher brilliance,better transverse coherence and better stability.The challenge of diffraction limited storage ring design is how to achieve the ultra low beam emittance with acceptable nonlinear performance.Effective linear and nonlinear parameter optimization methods based on Artificial Intelligence were developed for the storage ring physical design.As an example of application,partial physical design of HALS (Hefei Advanced Light Source),which is a diffraction limited VUV and soft X-ray light source,was introduced.Severe emittance growth due to the Intra Beam Scattering effect,which is the main obstacle to achieve ultra low emittance,was estimated quantitatively and possible cures were discussed.It is inspiring that better performance of diffraction limited storage ring can be achieved in principle with careful parameter optimization.

  14. Physics issues in diffraction limited storage ring design

    Science.gov (United States)

    Fan, Wei; Bai, ZhengHe; Gao, WeiWei; Feng, GuangYao; Li, WeiMin; Wang, Lin; He, DuoHui

    2012-05-01

    Diffraction limited electron storage ring is considered a promising candidate for future light sources, whose main characteristics are higher brilliance, better transverse coherence and better stability. The challenge of diffraction limited storage ring design is how to achieve the ultra low beam emittance with acceptable nonlinear performance. Effective linear and nonlinear parameter optimization methods based on Artificial Intelligence were developed for the storage ring physical design. As an example of application, partial physical design of HALS (Hefei Advanced Light Source), which is a diffraction limited VUV and soft X-ray light source, was introduced. Severe emittance growth due to the Intra Beam Scattering effect, which is the main obstacle to achieve ultra low emittance, was estimated quantitatively and possible cures were discussed. It is inspiring that better performance of diffraction limited storage ring can be achieved in principle with careful parameter optimization.

  15. Computational Modelling of Piston Ring Dynamics in 3D

    Directory of Open Access Journals (Sweden)

    Dlugoš Jozef

    2014-12-01

    Full Text Available Advanced computational models of a piston assembly based on the level of virtual prototypes require a detailed description of piston ring behaviour. Considering these requirements, the piston rings operate in regimes that cannot, in general, be simplified into an axisymmetric model. The piston and the cylinder liner do not have a perfect round shape, mainly due to machining tolerances and external thermo-mechanical loads. If the ring cannot follow the liner deformations, a local loss of contact occurs resulting in blow-by and increased consumption of lubricant oil in the engine. Current computational models are unable to implement such effects. The paper focuses on the development of a flexible 3D piston ring model based on the Timoshenko beam theory using the multibody system (MBS. The MBS model is compared to the finite element method (FEM solution.

  16. Shock accelerated vortex ring

    CERN Document Server

    Haehn, N; Oakley, J; Anderson, M; Rothamer, D; Bonazza, R

    2009-01-01

    The interaction of a shock wave with a spherical density inhomogeneity leads to the development of a vortex ring through the impulsive deposition of baroclinic vorticity. The present fluid dynamics videos display this phenomenon and were experimentally investigated at the Wisconsin Shock Tube Laboratory's (WiSTL) 9.2 m, downward firing shock tube. The tube has a square internal cross-section (0.25 m x 0.25 m) with multiple fused silica windows for optical access. The spherical soap bubble is generated by means of a pneumatically retracted injector and released into free-fall 200 ms prior to initial shock acceleration. The downward moving, M = 2.07 shock wave impulsively accelerates the bubble and reflects off the tube end wall. The reflected shock wave re-accelerates the bubble (reshock), which has now developed into a vortex ring, depositing additional vorticity. In the absence of any flow disturbances, the flow behind the reflected shock wave is stationary. As a result, any observed motion of the vortex rin...

  17. Ring Image Analyzer

    Science.gov (United States)

    Strekalov, Dmitry V.

    2012-01-01

    Ring Image Analyzer software analyzes images to recognize elliptical patterns. It determines the ellipse parameters (axes ratio, centroid coordinate, tilt angle). The program attempts to recognize elliptical fringes (e.g., Newton Rings) on a photograph and determine their centroid position, the short-to-long-axis ratio, and the angle of rotation of the long axis relative to the horizontal direction on the photograph. These capabilities are important in interferometric imaging and control of surfaces. In particular, this program has been developed and applied for determining the rim shape of precision-machined optical whispering gallery mode resonators. The program relies on a unique image recognition algorithm aimed at recognizing elliptical shapes, but can be easily adapted to other geometric shapes. It is robust against non-elliptical details of the image and against noise. Interferometric analysis of precision-machined surfaces remains an important technological instrument in hardware development and quality analysis. This software automates and increases the accuracy of this technique. The software has been developed for the needs of an R&TD-funded project and has become an important asset for the future research proposal to NASA as well as other agencies.

  18. Buoyant Norbury's vortex rings

    Science.gov (United States)

    Blyth, Mark; Rodriguez-Rodriguez, Javier; Salman, Hayder

    2014-11-01

    Norbury's vortices are a one-parameter family of axisymmetric vortex rings that are exact solutions to the Euler equations. Due to their relative simplicity, they are extensively used to model the behavior of real vortex rings found in experiments and in Nature. In this work, we extend the original formulation of the problem to include buoyancy effects for the case where the fluid that lies within the vortex has a different density to that of the ambient. In this modified formulation, buoyancy effects enter the problem through the baroclinic term of the vorticity equation. This permits an efficient numerical solution of the governing equation of motion in terms of a vortex contour method that tracks the evolution of the boundary of the vortex. Finally, we compare our numerical results with the theoretical analysis of the short-time evolution of a buoyant vortex. Funded by the Spanish Ministry of Economy and Competitiveness through grant DPI2011-28356-C03-02 and by the London Mathematical Society.

  19. APS Storage Ring vacuum chamber fabrication

    International Nuclear Information System (INIS)

    The 1104-m circumference Advanced Photon Source Storage Ring Vacuum System is composed of 240 individual sections, which are fabricated from a combination of aluminum extrusions and machined components. The vacuum chambers will have 3800 weld joints, each subject to strict vacuum requirements, as well as a variety of related design criteria. The vacuum criteria and chamber design are reviewed, including a discussion of the weld joint geometries. The critical fabrication process parameters for meeting the design requirements are discussed. The experiences of the prototype chamber fabrication program are presented. Finally, the required facilities preparation for construction activity is briefly described. 6 refs., 6 figs., 1 tab

  20. [Breathing waveform and respiratory ring in the role of mechanical ventilation].

    Science.gov (United States)

    Zhang, Jie; Chen, Guantao

    2010-03-01

    To learn reading respiratory waveform and ring is a key step to good use of respirator, which will help clinicians to analyze the status of the use of respirator and real time changes in patient's lung mechanics from the changes of respiratory wave and ring, for making use of respirator reasonably, scientifically and objectively to provide advanced methods. This article only explains the physical basis of respiratory wave and ring.

  1. n-X-Coherent Rings

    CERN Document Server

    Bennis, Driss

    2010-01-01

    This paper unifies several generalizations of coherent rings in one notion. Namely, we introduce $n$-$\\mathscr{X}$-coherent rings, where $\\mathscr{X}$ is a class of modules and $n$ is a positive integer, as those rings for which the subclass $\\mathscr{X}_n$ of $n$-presented modules of $\\mathscr{X}$ is not empty, and every module in $\\mathscr{X}_n$ is $n+1$-presented. Then, for each particular class $\\mathscr{X}$ of modules, we find correspondent relative coherent rings. Our main aim is to show that the well-known Chase's, Cheatham and Stone's, Enochs', and Stenstrom's characterizations of coherent rings hold true for any $n$-$\\mathscr{X}$-coherent rings.

  2. On thickness of Saturn rings

    International Nuclear Information System (INIS)

    Electronographic plates of Saturn were taken during the transit of the Earth through the ring plane. Observing conditions were more favorable than those prevailing in 1966. Thanks to the quality of the detectors and the telescopes, it has been possible to make a more precise photometric determination of the brightness of the ring seen edge on and to measure the brightness variation with respect to the distance to the center of the planet. Extrapolating to the case where the elevation of the Earth above the ring plane is strictly zero, we deduce an apparent photometric ring thickness equal to 1.5+-0.3 km. For an homogeneous layer of small particles colliding inelastically, theory predicts a thickness of the order of a few particles radii, i.e. a few tens of meters. The observed brightness could be explained by the E ring, the brightness of large chunks, condensations and warping of the ring

  3. Burnside Rings of Fusion Systems

    DEFF Research Database (Denmark)

    Reeh, Sune Precht

    , and we produce a basis for the Burnside ring that shares properties with the transitive sets for a finite group. We construct a transfer map from the p-local Burnside ring of the underlying p-group S to the p-local Burnside ring of F. Using such transfer maps, we give a new explicit construction...... of Burnside rings given by multiplication with the characteristic idempotent, and we show that this map is the transfer map previously constructed. Applying these results, we show that for every saturated fusion system the ring generated by all (non-idempotent) characteristic elements in the p-local double...... of the characteristic idempotent of F { the unique idempotent in the p-local double Burnside ring of S satisfying properties of Linckelmann and Webb. We describe this idempotent both in terms of fixed points and as a linear combination of transitive bisets. Additionally, using fixed points we determine the map...

  4. Precision ring rolling technique and application in high-performance bearing manufacturing

    Directory of Open Access Journals (Sweden)

    Hua Lin

    2015-01-01

    Full Text Available High-performance bearing has significant application in many important industry fields, like automobile, precision machine tool, wind power, etc. Precision ring rolling is an advanced rotary forming technique to manufacture high-performance seamless bearing ring thus can improve the working life of bearing. In this paper, three kinds of precision ring rolling techniques adapt to different dimensional ranges of bearings are introduced, which are cold ring rolling for small-scale bearing, hot radial ring rolling for medium-scale bearing and hot radial-axial ring rolling for large-scale bearing. The forming principles, technological features and forming equipments for three kinds of precision ring rolling techniques are summarized, the technological development and industrial application in China are introduced, and the main technological development trend is described.

  5. Filtration on a Ring Make a Quasi Valuation or Valuation Ring

    OpenAIRE

    Mohammad Hassan Anjom SHoa

    2014-01-01

    In this paper we show that if R is a filtered ring then we can define a quasi valuation ring. And there exists a valuation ring if R is some kind of filtered ring. Then we prove some properties and relations between filtered ring and quasi valuation ring and valuation ring.

  6. Filtration on a Ring Make a Quasi Valuation or Valuation Ring

    OpenAIRE

    SHoa, Mohammad Hassan Anjom

    2014-01-01

    In this paper we show that if R is a filtered ring then we can define a quasi valuation ring. And there exists a valuation ring if R is some kind of filtered ring. Then we prove some properties and relations between filtered ring and quasi valuation ring and valuation ring

  7. Platinum-catalysed intravaginal rings

    OpenAIRE

    Malcolm, Karl; Woolfson, David; Romano, Joseph

    2012-01-01

    The present invention provides improved intravaginal drug delivery devices, i.e., intravaginal rings, useful for the prophylactic administration of an antimicrobial compound, e.g., Dapivirine, to a human. The intravaginal rings of the invention address previous stability issues by utilizing a platinum catalyst (e.g., in the form of a platinum-siloxane complex) for the cross-linking reaction. The vaginal rings surprisingly achieve relatively high and steady release rates in vivo with a matrix ...

  8. On g-Semisymmetric Rings

    OpenAIRE

    Farahat S. Aly; Al Mestady, Mohammed O.

    2012-01-01

    We introduce right (left) g-semisymmetric ring as a new concept to generalize the well-known concept: symmetric ring. Examples are given to show that these classes of rings are distinct. They coincide under some conditions. It is shown that R is bounded right g-semisymmetric with boundary 1 from right if and only if R is symmetric, whenever R is regular. It is shown that a ring R is strongly regular if and only if R is regular and bounded right g-semisymmetric with boundary 1 from right. For ...

  9. Why Are Ring Galaxies Interesting?

    CERN Document Server

    Higdon, James L

    2010-01-01

    Compared with ordinary spirals, the ISM in ring galaxies experiences markedly different physical conditions and evolution. As a result, ring galaxies provide interesting perspectives on the triggering/quenching of large scale star formation and the destructive effects of massive stars on molecular cloud complexes. We use high resolution radio, sub-millimeter, infrared, and optical data to investigate the role of gravitational stability in star formation regulation, factors influencing the ISM's molecular fraction, and evidence of peculiar star formation laws and efficiencies in two highly evolved ring galaxies: Cartwheel and the Lindsay-Shapley ring.

  10. On Weakly P.P. Rings

    Institute of Scientific and Technical Information of China (English)

    Xiang Yue-ming; Ouyang Lun-qun; Wang Shu-gui

    2015-01-01

    We introduce, in this paper, the right weakly p.p. rings as the generaliza-tion of right p.p. rings. It is shown that many properties of the right p.p. rings can be extended onto the right weakly p.p. rings. Relative examples are constructed. As applications, we also characterize the regular rings and the semisimple rings in terms of the right weakly p.p. rings.

  11. The eRHIC Ring-Ring Collider Design

    CERN Document Server

    Wang, Fuhua; Beebe-Wang, Joanne; Deshpande, Abhay A; Farkhondeh, Manouchehr; Franklin, Wilbur; Graves, William; Litvinenko, Vladimir N; MacKay, William W; Milner, Richard; Montag, Christoph; Ozaki, Satoshi; Parker, Brett; Peggs, Steve; Ptitsyn, Vadim; Roser, Thomas; Tepikian, Steven; Trbojevic, Dejan; Tschalär, C; Wang, Dong; Zolfaghari, Abbasali; Zwart, Townsend; van der Laan, Jan

    2005-01-01

    The eRHIC ring-ring collider is the main design option of the future lepton-ion collider at Brookhaven National Laboratory. We report the revisions of the ring-ring collider design features to the baseline design presented in the eRHIC Zeroth Design Report (ZDR). These revisions have been made during the past year. They include changes of the interaction region which are required from the modifications in the design of the main detector. They also include changes in the lepton storage ring for high current operations as a result of better understandings of beam-beam interaction effects. The updated collider luminosity and beam parameters also take into account a more accurate picture of current and future operational aspects of RHIC.

  12. Magnetic fields in ring galaxies

    Science.gov (United States)

    Moss, D.; Mikhailov, E.; Silchenko, O.; Sokoloff, D.; Horellou, C.; Beck, R.

    2016-07-01

    Context. Many galaxies contain magnetic fields supported by galactic dynamo action. The investigation of these magnetic fields can be helpful for understanding galactic evolution; however, nothing definitive is known about magnetic fields in ring galaxies. Aims: Here we investigate large-scale magnetic fields in a previously unexplored context, namely ring galaxies, and concentrate our efforts on the structures that appear most promising for galactic dynamo action, i.e. outer star-forming rings in visually unbarred galaxies. Methods: We use tested methods for modelling α-Ω galactic dynamos, taking into account the available observational information concerning ionized interstellar matter in ring galaxies. Results: Our main result is that dynamo drivers in ring galaxies are strong enough to excite large-scale magnetic fields in the ring galaxies studied. The variety of dynamo driven magnetic configurations in ring galaxies obtained in our modelling is much richer than that found in classical spiral galaxies. In particular, various long-lived transients are possible. An especially interesting case is that of NGC 4513, where the ring counter-rotates with respect to the disc. Strong shear in the region between the disc and the ring is associated with unusually strong dynamo drivers in such counter-rotators. The effect of the strong drivers is found to be unexpectedly moderate. With counter-rotation in the disc, a generic model shows that a steady mixed parity magnetic configuration that is unknown for classical spiral galaxies, may be excited, although we do not specifically model NGC 4513. Conclusions: We deduce that ring galaxies constitute a morphological class of galaxies in which identification of large-scale magnetic fields from observations of polarized radio emission, as well as dynamo modelling, may be possible. Such studies have the potential to throw additional light on the physical nature of rings, their lifetimes, and evolution.

  13. Theory and analysis of nonlinear dynamics and stability in storage rings: A working group summary

    Energy Technology Data Exchange (ETDEWEB)

    Chattopadhyay, S.; Audy, P.; Courant, E.D.; Forest, E.; Guignard, G.; Hagel, J.; Heifets, S.; Keil, E.; Kheifets, S.; Mais, H.; Moshammer, H.; Pellegrini, C.; Pilat, F.; Suzuki, T.; Turchetti, G.; Warnock, R.L.

    1988-07-01

    A summary and commentary of the available theoretical and analytical tools and recent advances in the nonlinear dynamics, stability and aperture issues in storage rings are presented. 11 refs., 4 figs.

  14. Clean Elements in Abelian Rings

    Indian Academy of Sciences (India)

    Angelina Y M Chin

    2009-04-01

    Let be a ring with identity. An element in is said to be clean if it is the sum of a unit and an idempotent. is said to be clean if all of its elements are clean. If every idempotent in is central, then is said to be abelian. In this paper we obtain some conditions equivalent to being clean in an abelian ring.

  15. DELPHI's Ring Imaging Cherenkov Chamber

    CERN Multimedia

    1989-01-01

    The hundreds of mirrors around this Ring Imaging Cherenkov Chamber reflect cones of light created by fast moving particles to a detector. The velocity of a particle can be measured by the size of the ring produced on the detector. DELPHI, which ran from 1989 to 2000 on the LEP accelerator, was primarily concerned with particle identification.

  16. Reversible Seeding in Storage Rings

    Energy Technology Data Exchange (ETDEWEB)

    Ratner, Daniel; Chao, Alex; /SLAC

    2011-12-14

    We propose to generate steady-state microbunching in a storage ring with a reversible seeding scheme. High gain harmonic generation (HGHG) and echo-enabled harmonic generation (EEHG) are two promising methods for microbunching linac electron beams. Because both schemes increase the energy spread of the seeded beam, they cannot drive a coherent radiator turn-by-turn in a storage ring. However, reversing the seeding process following the radiator minimizes the impact on the electron beam and may allow coherent radiation at or near the storage ring repetition rate. In this paper we describe the general idea and outline a proof-of-principle experiment. Electron storage rings can drive high average power light sources, and free-electron lasers (FELs) are now producing coherent light sources of unprecedented peak brightness While there is active research towards high repetition rate FELs (for example, using energy recovery linacs), at present there are still no convenient accelerator-based sources of high repetition rate, coherent radiation. As an alternative avenue, we recently proposed to establish steady-state microbunching (SSMB) in a storage ring. By maintaining steady-state coherent microbunching at one point in the storage ring, the beam generates coherent radiation at or close to the repetition rate of the storage ring. In this paper, we propose a method of generating a microbunched beam in a storage ring by using reversible versions of linac seeding schemes.

  17. Almost ring theory - sixth release

    OpenAIRE

    Gabber, Ofer; Ramero, Lorenzo

    2002-01-01

    We develop almost ring theory, which is a domain of mathematics somewhere halfway between ring theory and category theory (whence the difficulty of finding appropriate MSC-class numbers). We apply this theory to valuation theory and to p-adic analytic geometry. You should really have a look at the introductions (each chapter has one).

  18. Constructions over localizations of rings

    Directory of Open Access Journals (Sweden)

    Alessandro Logar

    1987-11-01

    Full Text Available In this paper we construct a category of effective noetherian rings in which linear equations can be “solved”. This category is closed with respect to some important constructions like trascendental extensions, quotientations, finite products and localizations with respect to a large class of multiplicatively closed systems. Hence it gives a definition of “constructive” rings.

  19. A Note on Clean Rings

    Institute of Scientific and Technical Information of China (English)

    Zhou Wang; Jianlong Chen

    2007-01-01

    Let R be a ring and g(x) a polynomial in C[x],where C=C(R) denotes the center of R.Camillo and Sim6n called the ring g(x)-clean if every element of R can be written as the sum of a unit and a root of g(x).In this paper,we prove that for a,b (E) C,the ring R is clean and b - a is invertible in R if and only if R is g1(x)-clean,where gl(x) = (x - a)(x - b).This implies that in some sense the notion of g(x)-clean rings in the Nicholson-Zhou Theorem and in the Camillo-Sim6n Theorem is indeed equivalent to the notion of clean rings.

  20. Line-ratio based ring artifact correction method using transfer function

    Science.gov (United States)

    Oh, Daejoong; Hwang, Dosik; Kim, Younguk

    2016-03-01

    Computed tomography (CT) has been used for medical purposes. However there are many artifacts at CT images and that makes distorted image. Ring artifact is caused by non-uniform sensitivity of detectors and makes ring shape artifact. Line-ratio method was proposed to solve the problem however there are some problem at specific case. Therefore we propose advanced method to correct ring artifact using transfer function. As a result, ring artifacts can be removed at more global cases. Simulation data shows the proposed method outperforms the conventional line-ratio method.

  1. Black Hole Ringing, Quasinormal Modes, and Light Rings

    CERN Document Server

    Khanna, Gaurav

    2016-01-01

    Modelling of gravitational waves from binary black hole inspiral has played an important role in the recent observations of such signals. The late-stage ringdown phase of the gravitational waveform is often associated with the null particle orbit (\\light ring") of the black hole spacetime. With simple models we show that this link between the light ring and spacetime ringing is based more on the history of applications than on an actual constraining relationship. We also show, in particular, that a better understanding of the disassociation between the two, may be relevant to the astrophysically interesting case of rotating (Kerr) black holes.

  2. Is the bell ringing?

    CERN Multimedia

    Francesco Poppi

    2010-01-01

    During the Nobel prize-winning UA1 experiment, scientists in the control room used to ring a bell if a particularly interesting event had occurred. Today, the “CMS Exotica hotline” routine produces a daily report that lists the exotic events that were recorded the day before.   Display of an event selected by the Exotica routine. Take just a very small fraction of the available data (max. 5%); define the events that you want to keep and set the parameters accordingly; run the Exotica routine and only look at the very few images that the system has selected for you. This is the recipe that a small team of CMS researchers has developed to identify the signals coming from possible new physics processes. “This approach does not replace the accurate data analysis on the whole set of data. However, it is a very fast and effective way to focus on just a few events that are potentially very interesting”, explains Maurizio Pierini (CERN), who developed the...

  3. JAERI storage ring JSR

    International Nuclear Information System (INIS)

    A design study for a next generation 8 GeV synchrotron radiation facility is in progress in Japan, and the Japan Atomic Energy Research Institute (JAERI) and Institute of Physical and Chemical Research (RIKEN) have join forces in this project. A compact electron storage ring JSR has been under construction in the linac building in the Tokai Research Establishment of JAERI to serve for studies of various kind of accelerator technologies, examination of insertion devices and beam monitors, and training of young researchers. This paper describes the lattice design, injection system, magnets, vacuum system, RF system, control system and beam monitors and presents some operation results regarding the electron beam injection and storage. The JSR is presently in good condition concerning it's fundamental functions such as injection, storage at around 150 MeV and 300 MeV, and acceleration from 150 MeV and 300 MeV. Photon induced gas desorption is still large because the vacuum chamber has not been aged heavily by synchrotron radiation. (N.K.)

  4. Risk assessment of AMC (Advanced measurement and control systems). Survey of information security vulnerabilities in AMC.; Risikovurdering av AMS. Kartlegging av informasjonssikkerhetsmessige s#Latin Small Letter A With Ring Above#rbarheter i AMS.

    Energy Technology Data Exchange (ETDEWEB)

    Bartnes, Line Maria [NTNU, Trondheim (Norway); Johansen, Gorm Idar [NTNU, Trondheim (Norway); S#Latin Small Letter Ae#le, Hanne [Sintef Energy, Trondheim (Norway)

    2012-07-01

    SINTEF has carried out an overall assessment of Advanced measurement and control Systems (AMC) for Norway Water Resources and Energy Directorate (NVE). The assessment includes mainly AMC basis functions, which are record measurement data in customer and transfer these to the network, as well as wrestling / throttling power outlet in the each measuring point. Adjoining IT systems with network companies are considered only to a limited degree. The focus in analysis has been measuring point by geographical location, and the opportunity for both consumption and feed. Mobile devices such as measuring the charging of electric vehicles have not been touched upon in the analysis. It must be noted that this report provides an overall risk assessment related to general AMC technology and infrastructure. Each grid company must prepare their own risk assessments for their systems. The report describes a general AMC infrastructure with the refinements that have been made for this analysis. Then it is made an assessment on the basis of an information security perspective, the confidentiality, integrity and availability are the most important aspects. Different scenarios and events are presented and discussed, and the events that are judged to be at highest risk, one or more of the following elements out: - Unwanted shutdown of many customers - Software Error - Central system fails or used in the attack - Unfaithful servant's own employee misuses of knowledge and / or legitimate accesses In addition, a scenario with many gauges inoperative once considered to be critical, without cause need to be a targeted attack. This is because the consequences will incur substantial costs for repair and / or replacement of equipment. Malicious software could be causing, or a tool in several of events, especially at the onset that run from afar (remote connection). It is recommended that the Emergency Regulations should apply to AMC, because the risk assessment has been done shows that

  5. Generalized PP and Zip Subrings of Matrix Rings

    Institute of Scientific and Technical Information of China (English)

    LIU ZHONG-KUI; QIAO HU-SHENG

    2010-01-01

    Let R be an abelian ring. We consider a special subring An, relative to the ring An is a generalized right PP-ring (right zip ring) if and only if the ring R is a generalized right PP-ring (right zip ring). Our results yield more examples of generalized right PP-rings and right zip rings.

  6. Velocity peaks and caustic rings

    International Nuclear Information System (INIS)

    The late infall of cold dark matter onto an isolated galaxy produces flows with definite velocity vectors at any physical point in the galactic halo. It also produces caustic rings, which are places in space where the dark matter density is very large. The self-similar model of galactic halo formation predicts that the caustic ring radii an follow the approximate law an ≅ 1/n. Bumps in the rotation curves of NGC 3198 and of our own galaxy are interpreted as due to caustic rings of dark matter

  7. Schirmorganisation der Nordischen Bewegung: Der Nordische Ring und seine Repräsentanten in Norwegen

    Directory of Open Access Journals (Sweden)

    Nicola Karcher

    2009-07-01

    Full Text Available Nordischer Ring [Nordic Ring], founded in 1926, aimed to unite all groups in the Nordic Movement and to make the Nordic Thought, drafted by Hans F. K. Günther, to the leading ideology in Germany. Until the enforced political conformity of Nordischer Ring through incorporation into Nordische Gesellschaft [Nordic Society] in 1936, Nordischer Ring was able to build up far-reaching contacts not only to völkisch circles and among the nobility, but also to the NSDAP. In addition, the collaboration, advanced by Günther, of Norwegian researchers on the topic of race played an important role for the goals of Nordischer Ring, which hoped, in a long term perspective, to be able to establish the Nordic Thought in Norway and the other Scandinavian countries. This article traces the emergence and development of Nordischer Ring until its incorporation with a special focus on the contacts with Norwegian researchers on the topic of race.

  8. Vibration insensitive optical ring cavity

    Institute of Scientific and Technical Information of China (English)

    Miao Jin; Jiang Yan-Yi; Fang Su; Bi Zhi-Yi; Ma Long-Sheng

    2009-01-01

    The mounting configuration of an optical ring cavity is optimized for vibration insensitivity by finite element analysis. A minimum response to vertical accelerations is found by simulations made for different supporting positions.

  9. Prototype moving-ring reactor

    International Nuclear Information System (INIS)

    We have completed a design of the Prototype Moving-Ring Reactor. The fusion fuel is confined in current-carrying rings of magnetically-field-reversed plasma (Compact Toroids). The plasma rings, formed by a coaxial plasma gun, undergo adiabatic magnetic compression to ignition temperature while they are being injected into the reactor's burner section. The cylindrical burner chamber is divided into three burn stations. Separator coils and a slight axial guide field gradient are used to shuttle the ignited toroids rapidly from one burn station to the next, pausing for 1/3 of the total burn time at each station. D-T-3He ice pellets refuel the rings at a rate which maintains constant radiated power

  10. Perturbations of vortex ring pairs

    CERN Document Server

    Gubser, Steven S; Parikh, Sarthak

    2015-01-01

    We study pairs of co-axial vortex rings starting from the action for a classical bosonic string in a three-form background. We complete earlier work on the phase diagram of classical orbits by explicitly considering the case where the circulations of the two vortex rings are equal and opposite. We then go on to study perturbations, focusing on cases where the relevant four-dimensional transfer matrix splits into two-dimensional blocks. When the circulations of the rings have the same sign, instabilities are mostly limited to wavelengths smaller than a dynamically generated length scale at which single-ring instabilities occur. When the circulations have the opposite sign, larger wavelength instabilities can occur.

  11. Ring Model for Pneumatic Tires

    Institute of Scientific and Technical Information of China (English)

    危银涛; 范成建; 管迪华

    2002-01-01

    This paper reviews the state-of-the-art of the ring modeling method for tires, emphasizing the differences among the various tire ring models. A general tire ring model was then developed including all the nonlinear terms in the ring strain and the initial stresses induced by the internal pressure and rotation. The general equations of motion were derived from the Hamilton principle whth the geometric parameters for the model directly obtained from the tire design. The physical parameters were calculated from experimental mode parameters. A numerical example is given for a 195/70 R14-type tire. The analysis shows that the predicted natural frequencies and the tire mode shape agree well with experimental results.

  12. Autumn study on storage rings

    CERN Multimedia

    1974-01-01

    The first two weeks of October have seen storage ring people from accelerator Laboratories throughout the world at CERN to study the fundamental problems of very high energy protonproton colliding beam machines.

  13. Perturbations of vortex ring pairs

    Science.gov (United States)

    Gubser, Steven S.; Horn, Bart; Parikh, Sarthak

    2016-02-01

    We study pairs of coaxial vortex rings starting from the action for a classical bosonic string in a three-form background. We complete earlier work on the phase diagram of classical orbits by explicitly considering the case where the circulations of the two vortex rings are equal and opposite. We then go on to study perturbations, focusing on cases where the relevant four-dimensional transfer matrix splits into two-dimensional blocks. When the circulations of the rings have the same sign, instabilities are mostly limited to wavelengths smaller than a dynamically generated length scale at which single-ring instabilities occur. When the circulations have the opposite sign, larger wavelength instabilities can occur.

  14. Missing rings in Pinus halepensis

    OpenAIRE

    Novak, Klemen; De Luis, Martin; Saz, Miguel Angel; Longares, Luis Alberto; Serrano-Notivoli, Roberto; Raventós, Josep; Čufar, Katarina; Gričar, Jožica; Di Filippo, Alfredo; Piovesan, Gianluca; Rathgeber, Cyrille; Papadopoulos, Andreas; Kevin T. Smith

    2016-01-01

    Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE). These conditions are associated with decreased tree growth and increased vulnerability to pests and diseases. The anatomy of tree rings responds to these environmental conditions. Quantitatively, the width of a tree ring is largely determined by the rate and duration of cell division by the vascular cambium. In the Mediterranean cli...

  15. Collector ring project at FAIR

    Science.gov (United States)

    Dolinskii, A.; Berkaev, D.; Blell, U.; Dimopoulou, C.; Gorda, O.; Leibrock, H.; Litvinov, S.; Laier, U.; Koop, I.; Schurig, I.; Starostenko, A.; Shatunov, P.; Weinrich, U.

    2015-11-01

    The collector ring is a dedicated ring for fast cooling of ions coming from separators at the FAIR project. To accommodate optimal technical solutions, a structure of a magnet lattice was recently reviewed and modified. Consequently, more appropriate technical solutions for the main magnets could be adopted. A general layout and design of the present machine is shown. The demanding extraction schemes have been detailed and open design issues were completed.

  16. Friction between Ring Polymer Brushes

    OpenAIRE

    2015-01-01

    Friction between ring-polymer brushes at melt densities sliding past each other are studied using extensive course-grained molecular dynamics simulations and scaling arguments, and the results are compared to the friction between linear-polymer brushes. We show that for a velocity range spanning over three decades, the frictional forces measured for ring-polymer brushes are half the corresponding friction in case of linear brushes. In the linear-force regime, the weak inter-digitation of two ...

  17. ring og forandring

    DEFF Research Database (Denmark)

    I de sidste ti år har læring været på dagsordenen som aldrig før. Inden for uddannelsesverdenen og den pædagogiske debat har man kunnet se et markant skift, hvor læringsbegrebet er blevet tematiseret langt stærkere på bekostning af undervisningsbegrebet. Samtidig er læring blevet sat på dagsorden...

  18. Rings Whose Modules Have Grade Zero

    Institute of Scientific and Technical Information of China (English)

    Zhi Xiang WU

    2005-01-01

    In this paper, we prove that R is a two-sided Artinian ring and J is a right annihilator ideal if and only if (i) for any nonzero right module, there is a nonzero linear map from it to a projective module; (ii) every submodule of RR is not a radical module for some right coherent rings. We call a ring a right X ring if HomR(M, R) = 0 for any right module M implies that M = 0. We can prove some left Goldie and right X rings are right Artinian rings. Moreover we characterize semisimple rings by using X rings. A famous Faith's conjecture is whether a semipimary PF ring is a QF ring. Similarly we study the relationship between X rings and QF and get many interesting results.

  19. Collar nut and thrust ring

    Science.gov (United States)

    Lowery, Guy B.

    1991-01-01

    A collar nut comprises a hollow cylinder having fine interior threads at one end for threadably engaging a pump mechanical seal assembly and an inwardly depending flange at the other end. The flange has an enlarged portion with a groove for receiving an O-ring for sealing against the intrusion of pumpage from the exterior. The enlarged portion engages a thrust ring about the pump shaft for crushing a hard O-ring, such as a graphite O-ring. The hard O-ring seals the interior of the mechanical seal assembly and pump housing against the loss of lubricants or leakage of pumpage. The fine threads of the hollow cylinder provide the mechanical advantage for crushing the hard O-ring evenly and easily with a hand tool from the side of the collar nut rather than by tightening a plurality of bolts from the end and streamlines the exterior surface of the mechanical seal. The collar nut avoids the spatial requirements of bolt heads at the end of a seal and associated bolt head turbulence.

  20. Commissioning of the University of Maryland Electron Ring (UMER)

    CERN Document Server

    Bernal, Santiago; Feldman, Donald; Feldman, Renee; Godlove, Terry; Haber, Irving; Harris, John R; Holloway, Mike; Kishek, Rami A; Neumann, Jonathan G; Papadopoulos, Christos; Quinn, Bryan; Reiser, Martin; Stratakis, Diktys; Thangaraj, Jayakar C T; Tian, Kai; Walter, Mark; Wilson, Mark C

    2005-01-01

    The University of Maryland electron ring (UMER) is a low-energy, high current recirculator for beam physics research. The ring is completed for multi-turn operation of beams over a broad range of intensities and initial conditions. UMER is addressing issues in beam physics with relevance to many applications that rely on intense beams of high quality. Examples are advanced accelerators, FEL's, spallation neutron sources and future heavy-ion drivers for inertial fusion. We review the motivation, ring layout and operating conditions of UMER. Further, we present a summary of beam physics areas that UMER is currently investigating and others that are part of the commissioning plan: from transverse beam dynamics (matching, halo formation, strongly asymmetric beams, space-charge waves, etc), longitudinal dynamics (bunch capture/shaping, evolution of energy spread, longitudinal space-charge waves, etc.) to future upgrades and planned research (acceleration and resonance traversal, modeling of galactic dynamics, etc....

  1. Conducting liquid conveyer of plasma rings

    International Nuclear Information System (INIS)

    Current-carrying plasma rings can be conveyed in a cylindrical channel with a conducting liquid flow to which outer poloidal fields of the rings freeze. Fast tilting motion of the ring is stabilized when the liquid surface is set close to the ring within a critical distance. Effects of a resistive tube duct installed for the liquid are also examined. (author)

  2. Passive ring resonator micro-optical gyroscopes

    Science.gov (United States)

    Venediktov, V. Yu; Filatov, Yu V.; Shalymov, E. V.

    2016-05-01

    This paper reviews recent advances in passive micro-optical gyroscopes. In the last decade, most research effort in the area of micro-optical gyros has been concentrated on a configuration that takes advantage of a single-mode passive ring resonator, which is usually fabricated using integrated optical technologies. The dimensions of such micro-optical gyros are comparable to those of micromechanical gyroscopes (area of 10 to 100 mm2) and their sensitivity is considerably better than the sensitivity of the latter, approaching that of fibre-optic and laser gyros. Moreover, microoptical gyros can be made as a single integrated circuit, like the micromechanical gyros, but they have no movable parts, in contrast to their micromechanical counterparts. We also describe the development and investigation of micro-optical gyros produced in our studies.

  3. Concentric ring flywheel without expansion separators

    Science.gov (United States)

    Kuklo, Thomas C.

    1999-01-01

    A concentric ring flywheel wherein the adjacent rings are configured to eliminate the need for differential expansion separators between the adjacent rings. This is accomplished by forming a circumferential step on an outer surface of an inner concentric ring and forming a matching circumferential step on the inner surface of an adjacent outer concentric ring. During operation the circumferential steps allow the rings to differentially expand due to the difference in the radius of the rings without the formation of gaps therebetween, thereby eliminating the need for expansion separators to take up the gaps formed by differential expansion.

  4. Aromatic rings in chemical and biological recognition: energetics and structures.

    Science.gov (United States)

    Salonen, Laura M; Ellermann, Manuel; Diederich, François

    2011-05-16

    This review describes a multidimensional treatment of molecular recognition phenomena involving aromatic rings in chemical and biological systems. It summarizes new results reported since the appearance of an earlier review in 2003 in host-guest chemistry, biological affinity assays and biostructural analysis, data base mining in the Cambridge Structural Database (CSD) and the Protein Data Bank (PDB), and advanced computational studies. Topics addressed are arene-arene, perfluoroarene-arene, S⋅⋅⋅aromatic, cation-π, and anion-π interactions, as well as hydrogen bonding to π systems. The generated knowledge benefits, in particular, structure-based hit-to-lead development and lead optimization both in the pharmaceutical and in the crop protection industry. It equally facilitates the development of new advanced materials and supramolecular systems, and should inspire further utilization of interactions with aromatic rings to control the stereochemical outcome of synthetic transformations. PMID:21538733

  5. Ring wormholes via duality rotations

    Science.gov (United States)

    Gibbons, Gary W.; Volkov, Mikhail S.

    2016-09-01

    We apply duality rotations and complex transformations to the Schwarzschild metric to obtain wormhole geometries with two asymptotically flat regions connected by a throat. In the simplest case these are the well-known wormholes supported by phantom scalar field. Further duality rotations remove the scalar field to yield less well known vacuum metrics of the oblate Zipoy-Voorhees-Weyl class, which describe ring wormholes. The ring encircles the wormhole throat and can have any radius, whereas its tension is always negative and should be less than -c4 / 4 G. If the tension reaches the maximal value, the geometry becomes exactly flat, but the topology remains non-trivial and corresponds to two copies of Minkowski space glued together along the disk encircled by the ring. The geodesics are straight lines, and those which traverse the ring get to the other universe. The ring therefore literally produces a hole in space. Such wormholes could perhaps be created by negative energies concentrated in toroidal volumes, for example by vacuum fluctuations.

  6. Ring wormholes via duality rotations

    CERN Document Server

    Gibbons, Gary W

    2016-01-01

    We apply duality rotations and complex transformations to the Schwarzschild metric to obtain wormhole geometries with two asymptotically flat regions connected by a throat. In the simplest case these are the well-known wormholes supported by phantom scalar field. Further duality rotations remove the scalar field to yield less well known vacuum metrics of the oblate Zipoy-Voorhees-Weyl class, which describe ring wormholes. The ring encircles the wormhole throat and can have any radius, whereas its tension is always negative and should be less than $-c^4/4G$. If the tension reaches the maximal value, the geometry becomes exactly flat, but the topology remains non-trivial and corresponds to two copies of Minkowski space glued together along the disk encircled by the ring. The geodesics are straight lines, and those which traverse the ring get to the other universe. The ring therefore literally produces a whole in space. Such wormholes could perhaps be created by negative energies concentrated in toroidal volumes...

  7. Ring polymers in confined geometries

    CERN Document Server

    Usatenko, Z; Kuterba, P

    2016-01-01

    The investigation of a dilute solution of phantom ideal ring polymers and ring polymers with excluded volume interactions (EVI) in a good solvent confined in a slit geometry of two parallel repulsive walls and in a solution of colloidal particles of big size were performed. Taking into account the correspondence between the field theoretical $\\phi^4$ $O(n)$-vector model in the limit $n\\to 0$ and the behavior of long-flexible polymer chains in a good solvent the correspondent depletion interaction potentials, depletion forces and the forces which exert phantom ideal ring and ring polymer chains with EVI on the walls were obtained in the framework of the massive field theory approach at fixed space dimensions d=3 up to one-loop order. Additionally, the investigation of a dilute solution of phantom ideal ring polymers in a slit geometry of two inert walls and mixed walls with one repulsive and other one inert wall were performed and correspondent depletion interaction potentials and the depletion forces were cal...

  8. CYCLIC CODES OVER FORMAL POWER SERIES RINGS

    Institute of Scientific and Technical Information of China (English)

    Dougherty Steven T.; Liu Hongwei

    2011-01-01

    In this article, cyclic codes and negacyclic codes over formal power series rings are studied. The structure of cyclic codes over this class of rings is given, and the relationship between these codes and cyclic codes over finite chain rings is obtained. Using an isomorphism between cyclic and negacyclic codes over formal power series rings, the structure of negacyclic codes over the formal power series rings is obtained.

  9. A novel method for measuring energy loss in electron rings

    OpenAIRE

    Byrd, John M.; De Santis, Stefano

    2001-01-01

    We present a novel method for measuring the energy loss per turn in an electron storage ring. The method involves the accurate measurement of the change in the rotation period of an uncaptured electron bunch using a dual-sweep streak camera. In our opinion, this method is more direct and accurate than other techniques. We present examples of measurements performed at the Advanced Light Source.

  10. Plasma Structure and Behavior of Miniature Ring-Cusp Discharges

    OpenAIRE

    Mao, Hann-Shin

    2013-01-01

    Miniature ring-cusp ion thrusters provide a unique blend of high efficiencies and millinewton level thrust for future spacecraft. These thrusters are attractive as a primary propulsion for small satellites that require a high delta V, and as a secondary propulsion for larger spacecraft that require precision formation flying, disturbance rejection, or attitude control. To ensure desirable performance throughout the life of such missions, an advancement in the understanding of the plasma struc...

  11. On Ideals of Regular Rings

    Institute of Scientific and Technical Information of China (English)

    CHEN Huan Yin; LI Fu An

    2002-01-01

    In this paper, we investigate ideals of regular rings and give several characterizations for an ideal to satisfy the comparability. In addition, it is shown that, if Ⅰ is a minimal two-sided ideal of a regular ring R, then Ⅰ satisfies the comparability if and only if Ⅰ is separative. Furthermore, we prove that, for ideals with stable range one, Roth's problem has an affirmative solution. These extend the corresponding results on unit-regularity and one-sided unit-regularity.

  12. Nanoscale nonlinear PANDA ring resonator

    CERN Document Server

    Yupapin, Preecha

    2012-01-01

    Microring/nanoring resonator is an interesting device that has been widely studied and investigated by researchers from a variety of specializations. This book begins with the basic background of linear and nonlinear ring resonators. A novel design of nano device known as a PANDA ring resonator is proposed. The use of the device in the form of a PANDA in applications such as nanoelectronics, measurement, communication, sensors, optical and quantum computing, drug delivery, hybrid transistor and a new concept of electron-hole pair is discussed in detail.

  13. On Simple-Injective Rings

    Institute of Scientific and Technical Information of China (English)

    W.K. Nicholson; Jae Keol Park; M.F. Yousif

    2002-01-01

    A ring R is called right simple-injective if every R-linear map from a right ideal of R to R with simple image can be extended to R. It is shown that a right simple-injective ring R is quasi-Frobenius if R is right Goldie with essential right socle, or R is left perfect and the right annihilator of k ∈ R is finitely generated whenever kR or Rk is simple. This extends a result of Bjork.

  14. A Experimental Study of Viscous Vortex Rings.

    Science.gov (United States)

    Dziedzic, Mauricio

    Motivated by the role played by vortex rings in the process of turbulent mixing, the work is focused on the problem of stability and viscous decay of a single vortex ring. A new classification is proposed for vortex rings which is based on extensive hot-wire measurements of velocity in the ring core and wake and flow visualization. Vortex rings can be classified as laminar, wavy, turbulence-producing, and turbulent. Prediction of vortex ring type is shown to be possible based on the vortex ring Reynolds number. Linear growth rates of ring diameter with time are observed for all types of vortex rings, with different growth rates occurring for laminar and turbulent vortex rings. Data on the viscous decay of vortex rings are used to provide experimental confirmation of the accuracy of Saffman's equation for the velocity of propagation of a vortex ring. Experimental data indicate that instability of the vortex ring strongly depends on the mode of generation and can be delayed by properly adjusting the generation parameters. A systematic review of the literature on vortex-ring interactions is presented in the form of an appendix, which helps identify areas in which further research may be fruitful.

  15. SELF-DUAL PERMUTATION CODES OVER FORMAL POWER SERIES RINGS AND FINITE PRINCIPAL IDEAL RINGS

    Institute of Scientific and Technical Information of China (English)

    张光辉; 刘宏伟

    2013-01-01

    In this paper, we study self-dual permutation codes over formal power series rings and finite principal ideal rings. We first give some results on the torsion codes associated with the linear codes over formal power series rings. These results allow for obtaining some conditions for non-existence of self-dual permutation codes over formal power series rings. Finally, we describe self-dual permutation codes over finite principal ideal rings by examining permutation codes over their component chain rings.

  16. Characteristic of Rings. Prime Fields

    Directory of Open Access Journals (Sweden)

    Schwarzweller Christoph

    2015-12-01

    Full Text Available The notion of the characteristic of rings and its basic properties are formalized [14], [39], [20]. Classification of prime fields in terms of isomorphisms with appropriate fields (ℚ or ℤ/p are presented. To facilitate reasonings within the field of rational numbers, values of numerators and denominators of basic operations over rationals are computed.

  17. E-læring

    DEFF Research Database (Denmark)

    Heilesen, Simon

    2001-01-01

    E-læring er et modeord og et mantra. Undervisning bliver ikke automatisk bedre af, at der sættes et ”e-” foran. Forbedring og fornyelse af undervisningen er betinget af, at vi forstår computermediets muligheder og skaber forandring ved at tilpasse det til de undervisningsformer, vi ønsker....

  18. Singularities of ordinary deformation rings

    CERN Document Server

    Snowden, Andrew

    2011-01-01

    Let R^univ be the universal deformation ring of a residual representation of a local Galois group. Kisin showed that many loci in MaxSpec(R^univ[1/p]) of interest are Zariski closed, and gave a way to study the generic fiber of the corresponding quotient of R^univ. However, his method gives little information about the quotient ring before inverting p. We give a method for studying this quotient in certain cases, and carry it out in the simplest non-trivial case. Precisely, suppose that V_0 is the trivial two dimensional representation and let R be the unique Z_p-flat and reduced quotient of R^univ such that MaxSpec(R[1/p]) consists of ordinary representations with Hodge--Tate weights 0 and 1. We describe the functor of points of (a slightly modified version of) R and show that the irreducile components of Spec(R) are normal, Cohen--Macaulay and not Gorenstein. This has two well-known applications to global deformation rings: first, a global deformation ring employing these local conditions is torsion-free; a...

  19. Ringing phenomenon in silica microspheres

    Institute of Scientific and Technical Information of China (English)

    Chunhua Dong; Changling Zou; Jinming Cui; Yong Yang; Zhengfu Han; Guangcan Guo

    2009-01-01

    Whispering gallery modes in silica microspheres are excited by a tunable continuous-wave laser through the fiber taper. Ringing phenomenon can be observed with high frequency sweeping speed. The thermal nonlinearity in the microsphere can enhance this phenomenon. Our measurement results agree very well with the theoretical predictions by the dynamic equation.

  20. The Lord of the Rings

    Institute of Scientific and Technical Information of China (English)

    潘金梅

    2002-01-01

    Peter Jackson's first film in The Lord of the Rings trilogy (三步曲) has just grabbed (夺得) four Oscars-awards for the best make-up, best cinematography (摄影), best visual effects and best original score.Chinese audience had a chance to watch the fihn from late April.

  1. Generalized Double Ring Network Structures

    DEFF Research Database (Denmark)

    Pedersen, Jens Myrup; Patel, A.; Knudsen, Thomas Phillip;

    2004-01-01

    This paper describes and studies generalizations of the well-known double ring network structures. Two classes of structures are studied, the N2R(p; q) and N2R(p; q; r) structures, of which the former is a special case of the well known Generalized Petersen Graphs. Basic properties of these struc...

  2. Cascaded uncoupled dual-ring modulator

    CERN Document Server

    Gu, Tingyi; Wong, Chee Wei; Dong, Po

    2014-01-01

    We demonstrate that by coherent driving two uncoupled rings in same direction, the effective photon circulating time in the dual ring modulator is reduced, with increased modulation quality. The inter-ring detuning dependent photon dynamics, Q-factor, extinction ratio and optical modulation amplitude of two cascaded silicon ring resonators are studied and compared with that of a single ring modulator. Experimentally measured eye diagrams, together with coupled mode theory simulations, demonstrate the enhancement of dual ring configuration at 20 Gbps with a Q ~ 20,000.

  3. High-Speed Ring Bus

    Science.gov (United States)

    Wysocky, Terry; Kopf, Edward, Jr.; Katanyoutananti, Sunant; Steiner, Carl; Balian, Harry

    2010-01-01

    The high-speed ring bus at the Jet Propulsion Laboratory (JPL) allows for future growth trends in spacecraft seen with future scientific missions. This innovation constitutes an enhancement of the 1393 bus as documented in the Institute of Electrical and Electronics Engineers (IEEE) 1393-1999 standard for a spaceborne fiber-optic data bus. It allows for high-bandwidth and time synchronization of all nodes on the ring. The JPL ring bus allows for interconnection of active units with autonomous operation and increased fault handling at high bandwidths. It minimizes the flight software interface with an intelligent physical layer design that has few states to manage as well as simplified testability. The design will soon be documented in the AS-1393 standard (Serial Hi-Rel Ring Network for Aerospace Applications). The framework is designed for "Class A" spacecraft operation and provides redundant data paths. It is based on "fault containment regions" and "redundant functional regions (RFR)" and has a method for allocating cables that completely supports the redundancy in spacecraft design, allowing for a complete RFR to fail. This design reduces the mass of the bus by incorporating both the Control Unit and the Data Unit in the same hardware. The standard uses ATM (asynchronous transfer mode) packets, standardized by ITU-T, ANSI, ETSI, and the ATM Forum. The IEEE-1393 standard uses the UNI form of the packet and provides no protection for the data portion of the cell. The JPL design adds optional formatting to this data portion. This design extends fault protection beyond that of the interconnect. This includes adding protection to the data portion that is contained within the Bus Interface Units (BIUs) and by adding to the signal interface between the Data Host and the JPL 1393 Ring Bus. Data transfer on the ring bus does not involve a master or initiator. Following bus protocol, any BIU may transmit data on the ring whenever it has data received from its host. There

  4. The Canarias Einstein ring: a newly discovered optical Einstein ring

    Science.gov (United States)

    Bettinelli, M.; Simioni, M.; Aparicio, A.; Hidalgo, S. L.; Cassisi, S.; Walker, A. R.; Piotto, G.; Valdes, F.

    2016-09-01

    We report the discovery of an optical Einstein ring in the Sculptor constellation, IAC J010127-334319, in the vicinity of the Sculptor dwarf spheroidal galaxy. It is an almost complete ring (˜300°) with a diameter of ˜4.5 arcsec. The discovery was made serendipitously from inspecting Dark Energy Camera (DECam) archive imaging data. Confirmation of the object nature has been obtained by deriving spectroscopic redshifts for both components, lens and source, from observations at the 10.4 m Gran Telescopio CANARIAS (GTC) with the spectrograph OSIRIS. The lens, a massive early-type galaxy, has a redshift of z = 0.581, while the source is a starburst galaxy with redshift of z = 1.165. The total enclosed mass that produces the lensing effect has been estimated to be Mtot = (1.86 ± 0.23) × 1012 M⊙.

  5. Planetary science: Shepherds of Saturn's ring

    Science.gov (United States)

    Crida, Aurélien

    2015-09-01

    Saturn's F ring is chaperoned on both sides by the tiny moons Prometheus and Pandora. Numerical simulations show that this celestial ballet can result from the collision of two aggregates that evolved out of Saturn's main rings.

  6. Traumatic corneal endothelial rings from homemade explosives.

    Science.gov (United States)

    Ng, Soo Khai; Rudkin, Adam K; Galanopoulos, Anna

    2013-08-01

    Traumatic corneal endothelial rings are remarkably rare ocular findings that may result from blast injury. We present a unique case of bilateral traumatic corneal endothelial rings secondary to blast injury from homemade explosives. PMID:23474743

  7. The Structure of gr-simple Rings

    Institute of Scientific and Technical Information of China (English)

    朱彬

    2003-01-01

    A characterization of gr-simple rings is given by using the notion of componentwise-dense subrings of a full matrix ring over a division ring. As a conse-quence, any G-graded full matrix ring over a division ring is isomorphic to a dense subring of a full matrix ring with a good G-grading. Some conditions for a grading of a full matrix ring to be isomorphic to a good one are given, which generalize some results in: Dáscáscu, S., Lon, B., Niǎstǎsescu, C. and Montes, J. R., Group gradingson full matrix rings, J. Algebra, 220(1999), 709-728.

  8. International Tree Ring Data Bank (ITRDB)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Tree ring data from the International Tree Ring Data Bank and World Data Center for Paleoclimatology archives. Data include raw treering measurements (most are...

  9. Access control and interlock system at the Advanced Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Forrestal, J.; Hogrefe, R.; Knott, M.; McDowell, W.; Reigle, D.; Solita, L.; Koldenhoven, R.; Haid, D. [Argonne National Lab., IL (United States). Advanced Photon Source

    1997-08-01

    The Advanced Photon Source (APS) consists of a linac, position accumulator ring (PAR), booster synchrotron, storage ring, and up to 70 experimental beamlines. The Access Control and Interlock System (ACIS) utilizes redundant programmable logic controllers (PLCs) and a third hard-wired chain to protect personnel from prompt radiation generated by the linac, PAR, synchrotron, and storage ring. This paper describes the ACIS`s design philosophy, configuration, hardware, functionality, validation requirements, and operational experience.

  10. The Conversion and operation of the Cornell electron storage ring as a test accelerator (CESRTA) for damping rings research and development

    International Nuclear Information System (INIS)

    In March of 2008, the Cornell Electron Storage Ring (CESR) concluded twenty eight years of colliding beam operations for the CLEO high energy physics experiment. We have reconfigured CESR as an ultra low emittance damping ring for use as a test accelerator (CesrTA) for International Linear Collider (ILC) damping ring R and D. The primary goals of the CesrTA program are to achieve a beam emittance approaching that of the ILC Damping Rings with a positron beam, to investigate the interaction of the electron cloud with both low emittance positron and electron beams, to explore methods to suppress the electron cloud, and to develop suitable advanced instrumentation required for these experimental studies (in particular a fast x-ray beam size monitor capable of single pass measurements of individual bunches). We report on progress with the CESR conversion activities, the status and schedule for the experimental program, and the first experimental results that have been obtained.

  11. Optical fiber having wave-guiding rings

    Science.gov (United States)

    Messerly, Michael J.; Dawson, Jay W.; Beach, Raymond J.; Barty, Christopher P. J.

    2011-03-15

    A waveguide includes a cladding region that has a refractive index that is substantially uniform and surrounds a wave-guiding region that has an average index that is close to the index of the cladding. The wave-guiding region also contains a thin ring or series of rings that have an index or indices that differ significantly from the index of the cladding. The ring or rings enable the structure to guide light.

  12. Hidden Beauty in Twisted Viking Neck Rings

    OpenAIRE

    Olsen, Kasper; Bohr, Jakob

    2010-01-01

    Many hoards found in Ireland, Scotland, Orkney Islands, and Scandinavia demonstrate the vikings ability to fabricate beautiful arm and neck rings of twisted silver and gold rods. Characteristic for such rings is the uniform appearance of the twisted pattern along the length of the arm ring, as well as from one arm ring to another, also when found at distant geographical locations. How can the appearance of the twisted wires be so perfectly repetitive? We demonstrate that the answer is that th...

  13. Nonlinear analysis of ring oscillator circuits

    KAUST Repository

    Ge, Xiaoqing

    2010-06-01

    Using nonlinear systems techniques, we analyze the stability properties and synchronization conditions for ring oscillator circuits, which are essential building blocks in digital systems. By making use of its cyclic structure, we investigate local and global stability properties of an n-stage ring oscillator. We present a sufficient condition for global asymptotic stability of the origin and obtain necessity if the ring oscillator consists of identical inverter elements. We then give a synchronization condition for identical interconnected ring oscillators.

  14. Dysphagia due to Multiple Esophageal Rings

    Directory of Open Access Journals (Sweden)

    Stephen N Sullivan

    1995-01-01

    Full Text Available A 27-year-old Saudi man with dysphagia due to multiple esophageal rings is reported and the literature reviewed. Dysphagia due to multiple esophageal rings is very rare. Only 15 cases have been reported. The patient is usually male and has had dysphagia for many years when presenting. The cause of the rings is unknown. Theories to explain dysphagia are that the rings are either congenital or an unusual manifestation of gastroesophageal reflux.

  15. Positron Options for the Linac-Ring LHeC

    CERN Document Server

    Zimmermann, F; Papaphilippou, Y; Schulte, D; Sievers, P; Rinolfi, L; Variola, A; Zomer, F; Braun, H H; Yakimenko, V; Bulyak, E V; Klein, M

    2012-01-01

    The full physics program of a future Large Hadron electron Collider (LHeC) [1] requires both pe+ and pe− collisions. For a pulsed 140-GeV or an ERL-based 60-GeV Linac-Ring LHeC this implies a challenging rate of, respectively, about 1.8 × 1015 or 4.4 × 1016 e+/s at the collision point, which is about 300 or 7000 times the rate previously obtained, at the SLAC Linear Collider (SLC). We consider providing this e+ rate through a combination of measures: (1) Reducing the required production rate from the e+ target through colliding e+ (and the LHC protons) several times before deceleration, by reusing the e+ over several acceleration/deceleration cycles, and by cooling them, e.g., with a compact tri-ring scheme or a conventional damping ring in the SPS tunnel. (2) Using an advanced target, e.g., W-granules, rotating wheel, slicedrod converter, or liquid metal jet, for converting gamma rays to e+. (3) Selecting the most powerful of several proposed gamma sources, namely Compton ERL, Compton storage ring, coher...

  16. The neuronal and actin commitment: Why do neurons need rings?

    Science.gov (United States)

    Leite, Sérgio Carvalho; Sousa, Mónica Mendes

    2016-09-01

    The role of the actin cytoskeleton in neurons has been extensively studied in actin-enriched compartments such as the growth cone and dendritic spines. The recent discovery of actin rings in the axon shaft and in dendrites, together with the identification of axon actin trails, has advanced our understanding on actin organization and dynamics in neurons. However, specifically in the case of actin rings, the mechanisms regulating their nucleation and assembly, and the functions that they may exert in axons and dendrites remain largely unexplored. Here we discuss the possible structural, mechanistic and functional properties of the subcortical neuronal cytoskeleton putting the current knowledge in perspective with the information available on actin rings formed in other biological contexts, and with the organization of actin-spectrin lattices in other cell types. The detailed analysis of these novel neuronal actin ring structures, together with the elucidation of the function of actin-binding proteins in neuron biology, has a large potential to uncover new mechanisms of neuronal function under normal conditions that may have impact in our understanding of axon degeneration and regeneration. © 2016 Wiley Periodicals, Inc.

  17. RRF Rings which are not LRF

    Indian Academy of Sciences (India)

    K Varadarajan

    2000-05-01

    Define a ring to be RRF (respectively LRF) if every right (respectively left) -module is residually finite. We determine the necessary and sufficient conditions for a formal triangular matrix ring $$T=\\begin{pmatrix}A & 0\\\\ M & B\\end{pmatrix}$$ to be RRF (respectively LRF). Using this we give examples of RRF rings which are not LRF.

  18. On the intersection ring of graph manifolds

    OpenAIRE

    Doig, Margaret I.; Horn, Peter D.

    2014-01-01

    We calculate the intersection ring of three-dimensional graph manifolds with rational coefficients and give an algebraic characterization of these rings when the manifold's underlying graph is a tree. We are able to use this characterization to show that the intersection ring obstructs arbitrary three-manifolds from being homology cobordant to certain graph manifolds.

  19. Familial transmission of a ring chromosome 21

    DEFF Research Database (Denmark)

    Hertz, Jens Michael

    1987-01-01

    A ring chromosome 21 was found in a phenotypically normal mother and her son. The clinical findings in the son were bilateral retention of the testes and a slightly delayed puberty onset. Consequences of a ring formation of a chromosome 21 in phenotypically normal patients are presented...... and discussed, and the previously reported cases of familially transmitted G-group ring chromosomes are reviewed....

  20. The Phase Shift in the Jumping Ring

    Science.gov (United States)

    Jeffery, Rondo N.; Amiri, Farhang

    2008-01-01

    The popular physics demonstration experiment known as Thomson's Jumping Ring (JR) has been variously explained as a simple example of Lenz's law, or as the result of a phase shift of the ring current relative to the induced emf. The failure of the first-quadrant Lenz's law explanation is shown by the time the ring takes to jump and by levitation.…

  1. Interactions between unidirectional quantized vortex rings

    Science.gov (United States)

    Zhu, T.; Evans, M. L.; Brown, R. A.; Walmsley, P. M.; Golov, A. I.

    2016-08-01

    We have used the vortex filament method to numerically investigate the interactions between pairs of quantized vortex rings that are initially traveling in the same direction but with their axes offset by a variable impact parameter. The interaction of two circular rings of comparable radii produces outcomes that can be categorized into four regimes, dependent only on the impact parameter; the two rings can either miss each other on the inside or outside or reconnect leading to final states consisting of either one or two deformed rings. The fraction of energy that went into ring deformations and the transverse component of velocity of the rings are analyzed for each regime. We find that rings of very similar radius only reconnect for a very narrow range of the impact parameter, much smaller than would be expected from the geometrical cross-section alone. In contrast, when the radii of the rings are very different, the range of impact parameters producing a reconnection is close to the geometrical value. A second type of interaction considered is the collision of circular rings with a highly deformed ring. This type of interaction appears to be a productive mechanism for creating small vortex rings. The simulations are discussed in the context of experiments on colliding vortex rings and quantum turbulence in superfluid helium in the zero-temperature limit.

  2. Type Ⅱ codes over finite rings

    Institute of Scientific and Technical Information of China (English)

    DOUGHERTY; Steven; T

    2010-01-01

    In this paper,we generalize the concept of Type Ⅱ codes to arbitrary finite rings. We focus on Type Ⅱ codes over finite chain rings and use the Chinese Remainder Theorem on these codes to study Type Ⅱ codes over principal ideal rings.

  3. Self-gravitation in Saturn's rings

    International Nuclear Information System (INIS)

    In a ring-shaped collisional system self-gravitation reduces the equilibrium values of the geometric and optical thickness. In Saturn's rings both effects are appreciable. The previously found discrepancy between the calculated profile and the observed profile of the rings is chiefly caused by the omission of self-gravitation. (Auth.)

  4. E-læring

    DEFF Research Database (Denmark)

    Hansbøl, Mikala

    2010-01-01

    Når der etableres forbindelser mellem uddannelse og it, så sker der forandringer af, hvad det vil sige at tale om uddannelse. Uddannelsen har måske ikke en fysisk campus. Det er heller ikke sikkert, at man behøver at gå i formel skole eller tage musiktimer hos en musiklærer ansigt-til-ansigt for ...... lære at spille guitar. E-læring eller på engelsk e-learning vil sige, at undervisningen og dermed din læring sker med it - noget som man er nødt til at tage bestik af....

  5. Drag of buoyant vortex rings.

    Science.gov (United States)

    Vasel-Be-Hagh, Ahmadreza; Carriveau, Rupp; Ting, David S-K; Turner, John Stewart

    2015-10-01

    Extending from the model proposed by Vasel-Be-Hagh et al. [J. Fluid Mech. 769, 522 (2015)], a perturbation analysis is performed to modify Turner's radius by taking into account the viscous effect. The modified radius includes two terms; the zeroth-order solution representing the effect of buoyancy, and the first-order perturbation correction describing the influence of viscosity. The zeroth-order solution is explicit Turner's radius; the first-order perturbation modification, however, includes the drag coefficient, which is unknown and of interest. Fitting the photographically measured radius into the modified equation yields the time history of the drag coefficient of the corresponding buoyant vortex ring. To give further clarification, the proposed model is applied to calculate the drag coefficient of a buoyant vortex ring at a Bond number of approximately 85; a similar procedure can be applied at other Bond numbers. PMID:26565349

  6. Drag of buoyant vortex rings

    Science.gov (United States)

    Vasel-Be-Hagh, Ahmadreza; Carriveau, Rupp; Ting, David S.-K.; Turner, John Stewart

    2015-10-01

    Extending from the model proposed by Vasel-Be-Hagh et al. [J. Fluid Mech. 769, 522 (2015), 10.1017/jfm.2015.126], a perturbation analysis is performed to modify Turner's radius by taking into account the viscous effect. The modified radius includes two terms; the zeroth-order solution representing the effect of buoyancy, and the first-order perturbation correction describing the influence of viscosity. The zeroth-order solution is explicit Turner's radius; the first-order perturbation modification, however, includes the drag coefficient, which is unknown and of interest. Fitting the photographically measured radius into the modified equation yields the time history of the drag coefficient of the corresponding buoyant vortex ring. To give further clarification, the proposed model is applied to calculate the drag coefficient of a buoyant vortex ring at a Bond number of approximately 85; a similar procedure can be applied at other Bond numbers.

  7. On co-semihereditary rings

    Institute of Scientific and Technical Information of China (English)

    薛卫民

    1997-01-01

    A ring R is left co-semihereditary (strongly left co-semihereditary) if every finitely cogenerated factor of a finitely cogenerated (arbitrary) injective left R-module is injective.A left co-semihereditary ring,which is not strongly left co-semihereditary,is given to answer a question of Miller and Tumidge in the negative.If RUS defines a Morita duality,R is proved to be left co-semihereditary (left semihereditary) if and only if S is right semihereditary (right co-semihereditary).Assuming that S≥R is an almost excellent extension,S is shown to be (strongly) right co-semihereditary if and only if R is (strongly) right co-semihereditary.

  8. ring og it

    DEFF Research Database (Denmark)

      Antologien er et bidrag til didaktiske diskussioner om brug af f.eks. programpakker til sprogundervisning, præsentationsprogrammel og konferencesystemer på de videregående uddannelser. Antologien diskuterer ideen om, at multimediale medier og internettet kan understøtte læring, undervisning og ...... samarbejde ud fra konkrete eksempler på it-anvendelser, hvor fokus er på potentialer, barrierer og faldgruber....

  9. Selvreguleret læring

    DEFF Research Database (Denmark)

    Pedersen, Kirsten Hyldahl

    2012-01-01

    forudsætninger. For mange lærere er differentieret undervisning dog et diffust begreb, der kan være vanskeligt at forholde sig til i praksis. I denne artikel vil jeg derfor forsøge at svare på, om der kan findes en undervisningsstrategi, der vægter selvreguleret læring som værktøj, til at differentiere...

  10. Clic ring to main Linac

    CERN Document Server

    Stulle, F; Snuverink, J; Latina, A; Molloy, S

    2010-01-01

    The low emittance transport had been identified as one of the feasibility issues for CLIC. We discuss beam dynamics challenges occurring in the beam lines connecting the damping rings and the main linac. And we outline how these motivate design choices for the general RTML layout as well as its integration into the overall CLIC layout. Constraints originating from longitudinal dynamics and stabilization requirements of beam energy and phase at the main linac entrance are emphasized.

  11. Two Superconducting Storage Rings: ISABELLE

    Energy Technology Data Exchange (ETDEWEB)

    Sanford, J. R.

    1978-01-01

    The general features of the design and the status of the ISABELLE storage ring project at the present time are reported. It brings up to date the results reported at the National Particle Accelerator Conference in March 1977. The most significant change since that time has been an upgrading of the energy of the overall facility, and acceptance of the project by the Department of Energy.

  12. ring mellem elever

    DEFF Research Database (Denmark)

    Georgsen, Marianne; Davidsen, Jacob

    2010-01-01

    I denne rapport præsenteres resultater fra følgeforskningen til projektet Læring gennem Bevægelse, som er gennemført på Søndervangskolen i Hammel i perioden august 2009 - maj 2010. Projektet er gennemført i samspil mellem lærere, it-vejleder, elever og skolens ledelse. Projektets overordnede formål...

  13. ring mellem elever

    DEFF Research Database (Denmark)

    Davidsen, Jacob; Georgsen, Marianne

    I denne rapport tilbyder vi et indblik i det gennemførte projekt, og forfatterne har valgt nogle forhold ud, som belyses og diskuteres, mens andre ikke berøres eller diskuteres nævneværdigt i denne rapport. Det skyldes blandt andet projektets mange facetter, som dækker både læring, teknologi, pæd...

  14. THE RELATION BETWEEN QUASI VALUATION AND VALUATION RING AND FILTERED RING

    OpenAIRE

    Mohammad Hassan Anjom SHoa

    2014-01-01

    In this paper we show the relation between filtered ring and quasi valuation and valuation ring . We show if R is a filtered ring then we can define a quasi valuation. And if R is some kind of filtered ring then we can define a valuation. Then we prove some properties and relations for R.

  15. THE RELATION BETWEEN QUASI VALUATION AND VALUATION RING AND FILTERED RING

    OpenAIRE

    SHoa, Mohammad Hassan Anjom

    2014-01-01

    In this paper we show the relation between filtered ring and quasi valuation and valuation ring . We show if is a filtered ring then we can define a quasi valuation. And if is some kind of filtered ring then we can define a valuation. Then we prove some properties and relations for

  16. Contraceptive vaginal ring (NuvaRing)-a novel, convenient and effective contraceptive option

    Institute of Scientific and Technical Information of China (English)

    Chen Wei-lin; Fan Guang-sheng

    2011-01-01

    Contraceptive vaginal ring (NuvaRing) is a new combined hormonal contraceptive method.Each ring contains 2.7mg ethinyl estradiol (EE) and 11.7mg etonogestrel.The ring is characteristic with its ease of use,lower EE systemic exposure and excellent cycle control.Studies have demonstrated that the efficacy and safety of the ring are equivalent to combined oral contraceptive (COC).The side effects of the ring are fewer and the biocompatibility is good.Recent studies have proved that the NuvaRing is a new,effective hormonal contraceptive option for women.

  17. Generalized fuzzy ideals of near-rings

    Institute of Scientific and Technical Information of China (English)

    ZHAN Jian-ming; Dawaz B.

    2009-01-01

    The concept of ((∈),(∈)V (q))-fuzzy subnear-rings (ideals) of a near-ring is introduced and some of its related properties are investigated. In particular, the relationships among ordinary fuzzy subnear-rings (ideals), (∈,∈V q)-fuzzy subnear-rings (ideals) and ((∈),(∈)V (q))-fuzzy subnearrings (ideals) of near-rings are described. Finally, some characterization of [μ]t is given by means of (∈,∈V q)-fuzzy ideals.

  18. K stability and stability of chiral ring

    CERN Document Server

    Collins, Tristan C; Yau, Shing-Tung

    2016-01-01

    We define a notion of stability for chiral ring of four dimensional N=1 theory by introducing test chiral rings and generalized a maximization. We conjecture that a chiral ring is the chiral ring of a superconformal field theory if and only if it is stable. We then study N=1 field theory derived from D3 branes probing a three-fold singularity X, and show that the K stability which implies the existence of Ricci-flat conic metric on X is equivalent to the stability of chiral ring of the corresponding field theory.

  19. Electrical Conduction of Some Fe3S3 Ring Compounds

    Institute of Scientific and Technical Information of China (English)

    WANG Jian; LIU Ping; YOU Gang

    2003-01-01

    @@ M3S3 cluster six-membered ring compounds are very interesting compounds liking aromatic benzene, and Cu, Pd, B and so on can also form M3S3 cluster besides Fe. [1,2] In recent years electrical conduction of some metal com plexes has been studied. [3,4] The study of electrical conduction through DNA molecules has illustrated that DNA is a semiconductor, but its principle of electrical conduction has not been revealed. [5,6] Electrical conduction of artificial synthesized Fe-S cluster compounds has not been reported. We hope to infer the function on electrical conduction of metal active centers of iron-sulfur proteins through study of electrical conduction of Fe3S3 ring compounds, paving the way for the discovery of new advanced biological functional materials.

  20. DYNAMICAL BALANCE STUDY OF RING REDUCER

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The basic structure of epicyclical gear transmission with inner teeth of single-ring, double-ring, three-ring and four-ring reducer are analyzed. The force analysis model of ring reducer is built. Following this, it is concluded that the present ring reducers have the problem that the inertia force or the inertia moment is lopsided. On the base of analysis and calculation the balanced ring reducer which can realize the balance of inertia force and inertia moment is brought forward, and so is its concrete realizing step. The specimen of the balanced ring reducer is designed and manufactured; the experiment is carried out on the gear transmission test bench. Compared with other ring reducer of the same power, the balanced ring reducer has many advantages, such as low vibration noise, low cost and less production difficulty and less heat. It is the substitute of other ring reducer of the same kind. Therefore, it has important theoretic significance and highly practical engineering value.

  1. Persistent current in a magnetized Rashba ring

    Institute of Scientific and Technical Information of China (English)

    Zhang Lin; Wang Jun

    2011-01-01

    We theoretically study the persistent currents flowing in a Rashba quantum ring subjected to the Rashba spinorbit interaction.By introducing uniform or nonuniform magnetization into the ring,we find that a nonzero persistent charge current circulates in the ring,which stems from the original equilibrium spin current due to the Rashba spinorbit interaction.Because of broken time reversal symmetry,the two oppositely flowing spin-up and spin-down charge currents of the equilibrium spin current are no longer equal,and so a net persistent charge current can flow in the system.It is also found that the persistent current can be modulated by the Fermi energy,the Rashba spin-orbit interaction strength and the magnetization in the ring.Moreover,the magnetization perpendicular to the ring plane can optimize the current.The persistent current flowing in the ring is a manifestation of the nonzero equilibrium spin current existing in the ring.

  2. Feasibility of a ring FEL at low emittance storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Agapov, I., E-mail: ilya.agapov@xfel.eu

    2015-09-01

    A scheme for generating coherent radiation at latest generation low emittance storage rings such as PETRA III at DESY (Balewski et al., 2004 [1]) is proposed. The scheme is based on focusing and subsequent defocusing of the electron beam in the longitudinal phase space at the undulator location. The expected performance characteristics are estimated for radiation in the wavelength range of 500–1500 eV. It is shown that the average brightness is increased by several orders of magnitude compared to spontaneous undulator radiation, which can open new perspectives for photon-hungry soft X-ray spectroscopy techniques.

  3. Rings with each right ideal automorphism-invariant

    OpenAIRE

    KOŞAN, M. Tamer; Quynh, Truong Cong; Srivastava, Ashish K.

    2015-01-01

    In this paper, we study rings having the property that every right ideal is automorphism-invariant. Such rings are called right $a$-rings. It is shown that (1) a right $a$-ring is a direct sum of a square-full semisimple artinian ring and a right square-free ring, (2) a ring $R$ is semisimple artinian if and only if the matrix ring $\\mathbb{M}_n(R)$ for some $n>1$ is a right $a$-ring, (3) every right $a$-ring is stably-finite, (4) a right $a$-ring is von Neumann regular if and only if it is s...

  4. Einstein Ring in Distant Universe

    Science.gov (United States)

    2005-06-01

    Using ESO's Very Large Telescope, Rémi Cabanac and his European colleagues have discovered an amazing cosmic mirage, known to scientists as an Einstein Ring. This cosmic mirage, dubbed FOR J0332-3557, is seen towards the southern constellation Fornax (the Furnace), and is remarkable on at least two counts. First, it is a bright, almost complete Einstein ring. Second, it is the farthest ever found. ESO PR Photo 20a/05 ESO PR Photo 20a/05 Deep Image of a Region in Fornax (FORS/VLT) [Preview - JPEG: 400 x 434 pix - 60k] [Normal - JPEG: 800 x 867 pix - 276k] [Full Res - JPEG: 1859 x 2015 pix - 3.8M] ESO PR Photo 20b/05 ESO PR Photo 20b/05 Zoom-in on the Newly Found Einstein Ring (FORS/VLT) [Preview - JPEG: 400 x 575 pix - 168k] [Normal - JPEG: 630 x 906 pix - 880k] Caption: ESO PR Photo 20a/05 is a composite image taken in two bands (B and R) with VLT/FORS1 of a small portion of the sky (field-of-view 7x7' or 1/15th of the area of the full moon). The faintest object seen in the image has a magnitude 26, that is, it is 100 million times fainter than what can be observed with the unaided eye. The bright elliptical galaxy on the lower-left quadrant is a dwarf galaxy part of a large nearby cluster in the Fornax constellation. As for all deep images of the sky, this field shows a variety of objects, the brightest ponctual sources being stars from our Galaxy. By far the field is dominated by thousands of faint background galaxies the colours of which are related to the age of their dominant stellar population, their dust content and their distance. The newly found Einstein ring is visible in the top right part of the image. ESO PR Photo 20b/05 zooms-in on the position of the newly found cosmic mirage. ESO PR Photo 20c/05 ESO PR Photo 20c/05 Einstein Ring in Distant Universe (FORS/VLT) [Preview - JPEG: 400 x 584 pix - 104k] [Normal - JPEG: 800 x 1168 pix - 292k] [Full Res - JPEG: 1502 x 2192 pix - 684k] Caption of ESO PR Photo 20c/05: The left image is magnified and centred

  5. The SABS finger ring service

    International Nuclear Information System (INIS)

    All radiation workers are required by law to wear personal dosimeters to measure the radiation dose they receive in the course of their work. However, there was a need to measure the radiation dose received by the fingers and hands, because they are much closer to the source of radiation than the rest of the body. In April 1982 a finger ring service was instituted on a routine basis. A thermoluminescent dosimeter (TLD) is used, which is suitable for both X-rays and gamma rays. Materials that are used for thermoluminescent dosimeters includes LiF:Mg, CaF2:Dy and CaSO4:Dy

  6. Viden og Læring

    DEFF Research Database (Denmark)

    Bordum, Anders

    2005-01-01

    Jeg vil i denne sammenhæng præsentere en fortolkning af hvordan Jürgen Habermas i forhold til klassisk epistemologi forstår viden og læring. Jeg vil argumentere for at vi i videnssamfundet har brug for den realistiske diskursbaserede model for videnstestning og vidensdannelse Habermas repræsenterer....... Endvidere vil jeg ved at rekonstruere Habermas' position med overbevisningen og propositionen som omdrejningspunkt vise at Habermas teori direkte kan omsættes som analysegrundlag og forståelsesramme for en hvilken som helst tematiseret praksis. Alt hvad der er virkeligt kan udtrykkes propositionelt. Den...

  7. Interface-læring

    DEFF Research Database (Denmark)

    Thorhauge, Sally

    2015-01-01

    Interface-læring er den læringsoplevelse, der kan opstå i grænsefladen mellem to væsensforskellige læringsmiljøer, når de mødes og griber ind i hinanden. Et gymnasium og et museum er eksempler på to sådanne læringsmiljøer. Artiklen præsenterer nogle af de væsentligste resultater fra min ph.d. afh.......d. afhandling Interface Learning - New goals for museum and upper secondary school collaboration (2014)....

  8. Nanofiber-segment ring resonator

    CERN Document Server

    Jones, D E; Franson, J D; Pittman, T B

    2016-01-01

    We describe a fiber ring resonator comprised of a relatively long loop of standard single-mode fiber with a short nanofiber segment. The evanescent mode of the nanofiber segment allows the cavity-enhanced field to interact with atoms in close proximity to the nanofiber surface. We report on an experiment using a warm atomic vapor and low-finesse cavity, and briefly discuss the potential for reaching the strong coupling regime of cavity QED by using trapped atoms and a high-finesse cavity of this kind.

  9. Nanofiber-segment ring resonator

    Science.gov (United States)

    Jones, D. E.; Hickman, G. T.; Franson, J. D.; Pittman, T. B.

    2016-08-01

    We describe a fiber ring resonator comprised of a relatively long loop of standard single-mode fiber with a short nanofiber segment. The evanescent mode of the nanofiber segment allows the cavity-enhanced field to interact with atoms in close proximity to the nanofiber surface. We report on an experiment using a warm atomic vapor and low-finesse cavity, and briefly discuss the potential for reaching the strong coupling regime of cavity QED by using trapped atoms and a high-finesse cavity of this kind.

  10. Storage ring proton EDM experiment

    CERN Document Server

    CERN. Geneva

    2015-01-01

    sensitivity of 10^-29 e-cm.  The strength of the method originates from the fact that there are high intensity polarized proton beams available and the fact that the so-called geometric phase systematic error background cancels with clock-wise and counter-clock-wise storage possible in electric rings. The ultimate sensitivity of the method is 10^-30 e-cm. At this level it will either detect a non-zero EDM or it will eliminate electro-weak baryogenesis.

  11. Springback Prediction on Slit-Ring Test

    Science.gov (United States)

    Chen, Xiao Ming; Shi, Ming F.; Ren, Feng; Xia, Z. Cedric

    2005-08-01

    Advanced high strength steels (AHSS) are increasingly being used in the automotive industry to reduce vehicle weight while improving vehicle crash performance. One of the concerns in manufacturing is springback control after stamping. Although computer simulation technologies have been successfully applied to predict stamping formability, they still face major challenges in springback prediction, particularly for AHSS. Springback analysis is very complicated and involves large deformation problems in the forming stage and mechanical multiplying effect during the elastic recovery after releasing a part from the die. Therefore, the predictions are very sensitive to the simulation parameters used. It is very critical in springback simulation to choose an appropriate material model, element formulation and contact algorithm. In this study, a springback benchmark test, the slit ring cup, is used in the springback simulation with commercially available finite element analysis (FEA) software, LS-DYNA. The sensitivity of seven simulation variables on springback predictions was investigated, and a set of parameters with stable simulation results was identified. Final simulations using the selected set of parameters were conducted on six different materials including two AHSS steels, two conventional high strength steels, one mild steel and an aluminum alloy. The simulation results are compared with experimental measurements for all six materials and a favorable result is achieved. Simulation errors as compared against test results falls within 10%.

  12. Interaction of ring dark solitons with ring impurities in Bose-Einstein condensates

    International Nuclear Information System (INIS)

    The interaction of ring dark solitons/vortexes with the ring-shaped repulsive and attractive impurities in two-dimensional Bose-Einstein condensates is investigated numerically. Very rich interaction phenomena are obtained, i.e., not only the interaction between the ring soliton and the impurity, but also the interaction between vortexes and the impurity. The interaction characters, i.e., snaking of ring soliton, quasitrapping or reflection of ring soliton and vortexes by the impurity, strongly depend on initial ring soliton velocity, impurity strength, initial position of ring soliton and impurity. The numerical results also reveal that ring dark solitons/vortexes can be trapped and dragged by an adiabatically moving attractive ring impurity

  13. Printable nanoscale metal ring arrays via vertically aligned carbon nanotube platforms.

    Science.gov (United States)

    Lee, Sang Ho; Yoon, Seungha; Jeong, Huisu; Han, Mingu; Choi, Sung Mook; Kim, Jong Guk; Park, Ji-Woong; Jung, Gun Young; Cho, Beong Ki; Kim, Won Bae

    2013-11-01

    This paper reports a novel and efficient strategy for fabricating sub-100 nm metal ring arrays using a simple printing process. Vertically aligned carbon nanotubes that are supported by hexagonally ordered channels of alumina matrices are used as a stamp to print nanoscale ring patterns, which is a very unique stamping platform that has never been reported. Using this strategy, uniform nanoring patterns of various metals can be directly printed onto a wide range of substrate surfaces under ambient conditions. Significantly, the size and interval of the printed nanorings can be systematically tuned by controlling the ring-shaped tip dimensions of the pristine stamps. An advanced example of these printable nanoscale metal ring arrays is explicitly embodied in this work by investigation of the plasmon resonances of metal nanorings with different sizes and intervals.

  14. The cryogenic storage ring CSR

    Science.gov (United States)

    von Hahn, R.; Becker, A.; Berg, F.; Blaum, K.; Breitenfeldt, C.; Fadil, H.; Fellenberger, F.; Froese, M.; George, S.; Göck, J.; Grieser, M.; Grussie, F.; Guerin, E. A.; Heber, O.; Herwig, P.; Karthein, J.; Krantz, C.; Kreckel, H.; Lange, M.; Laux, F.; Lohmann, S.; Menk, S.; Meyer, C.; Mishra, P. M.; Novotný, O.; O'Connor, A. P.; Orlov, D. A.; Rappaport, M. L.; Repnow, R.; Saurabh, S.; Schippers, S.; Schröter, C. D.; Schwalm, D.; Schweikhard, L.; Sieber, T.; Shornikov, A.; Spruck, K.; Sunil Kumar, S.; Ullrich, J.; Urbain, X.; Vogel, S.; Wilhelm, P.; Wolf, A.; Zajfman, D.

    2016-06-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm-3 is derived, equivalent to a room-temperature pressure below 10-14 mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

  15. The Cryogenic Storage Ring CSR

    CERN Document Server

    von Hahn, Robert; Berg, Felix; Blaum, Klaus; Breitenfeldt, Christian; Fadil, Hisham; Fellenberger, Florian; Froese, Michael; George, Sebastian; Göck, Jürgen; Grieser, Manfred; Grussie, Florian; Guerin, Elisabeth A; Heber, Oded; Herwig, Philipp; Karthein, Jonas; Krantz, Claude; Kreckel, Holger; Lange, Michael; Laux, Felix; Lohmann, Svenja; Menk, Sebastian; Meyer, Christian; Mishra, Preeti M; Novotný, Oldřich; Connor, Aodh P O; Orlov, Dmitry A; Rappaport, Michael L; Repnow, Roland; Saurabh, Sunny; Schippers, Stefan; Schröter, Claus Dieter; Schwalm, Dirk; Schweikhard, Lutz; Sieber, Thomas; Shornikov, Andrey; Spruck, Kaija; Kumar, Sudhakaran Sunil; Ullrich, Joachim; Urbain, Xavier; Vogel, Stephen; Wilhelm, Patrick; Wolf, Andreas; Zajfman, Daniel

    2016-01-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 $\\pm$ 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion) and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas den...

  16. Hermitian Groups over Local Rings

    Institute of Scientific and Technical Information of China (English)

    Guoping Tang

    2001-01-01

    The general hermitian group GH2n(R,a1,... ,ar) of rank n and its elementary subgroup EH2n(R,a1,... ,ar) were introduced by Bak [1] and Tang [4], respectively. It is known that EH2n(R, a1,... , ar) is perfect whenever n ≥ r+ 3 and the stable elementary hermitian group EH(R,a1,... ,ar) is the commutator subgroup of the stable general hermitian group GH(R, a1,... , ar).In this paper, we prove that, when R is a local ring, EH2n(R, a1,... , ar) is a normal subgroup of GH2n (R, a1,... , ar) if n ≥ r+2, and is the commutator subgroup of GH2n(R, a1,... , ar) if n ≥ r + 3. In the special case that R is a division ring,we show that the quotient group of GH2n(R, a1,... , ar) by EH2n(R, a1,... , ar)is independent of the choice of a1,... , ar.

  17. The cryogenic storage ring CSR.

    Science.gov (United States)

    von Hahn, R; Becker, A; Berg, F; Blaum, K; Breitenfeldt, C; Fadil, H; Fellenberger, F; Froese, M; George, S; Göck, J; Grieser, M; Grussie, F; Guerin, E A; Heber, O; Herwig, P; Karthein, J; Krantz, C; Kreckel, H; Lange, M; Laux, F; Lohmann, S; Menk, S; Meyer, C; Mishra, P M; Novotný, O; O'Connor, A P; Orlov, D A; Rappaport, M L; Repnow, R; Saurabh, S; Schippers, S; Schröter, C D; Schwalm, D; Schweikhard, L; Sieber, T; Shornikov, A; Spruck, K; Sunil Kumar, S; Ullrich, J; Urbain, X; Vogel, S; Wilhelm, P; Wolf, A; Zajfman, D

    2016-06-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm(-3) is derived, equivalent to a room-temperature pressure below 10(-14) mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams. PMID:27370434

  18. Hochschild and ordinary cohomology rings of small categories

    OpenAIRE

    Xu, Fei

    2008-01-01

    Advances in Mathematics, accepted Let C be a small category and k a field. There are two interesting mathematical subjects: the category algebra kC and the classifying space |C|=BC. We study the ring homomorphism HH^*(kC) ---> H^*(|C|,k) and prove it is split surjective, using the factorization category of Quillen and certain techniques from functor cohomology theory. This generalizes the well-known theorems for groups and posets. Based on this result, we construct a seven-dimensional cate...

  19. SLC positron damping ring optics design

    International Nuclear Information System (INIS)

    The basic SLAC Linear Collider operation scheme assumes the use of two damping rings, one for the e-, one for the e+, in order to reduce the colliding beam normalized emittances to 30 π μradm hence raising the corresponding luminosity by a factor 170. The e- damping ring optics, designed by H. Wiedemann, has been extensively studied and modelled since it's completion at the end of 1982. The e+ damping ring being built will be based on the same design except for some modifications resulting from the studies on the e- damping ring which clearly pointed out two major weak points as far as the optics is concerned. The present paper describes the basic modifications of the ring lattice and main equipment positions in order to improve the situation in the Positron Damping Ring. 16 refs., 2 figs., 1 tab

  20. A first course in noncommutative rings

    CERN Document Server

    Lam, T Y

    2001-01-01

    A First Course in Noncommutative Rings, an outgrowth of the author's lectures at the University of California at Berkeley, is intended as a textbook for a one-semester course in basic ring theory. The material covered includes the Wedderburn-Artin theory of semisimple rings, Jacobson's theory of the radical, representation theory of groups and algebras, prime and semiprime rings, local and semilocal rings, perfect and semiperfect rings, etc. By aiming the level of writing at the novice rather than the connoisseur and by stressing th the role of examples and motivation, the author has produced a text that is suitable not only for use in a graduate course, but also for self- study in the subject by interested graduate students. More than 400 exercises testing the understanding of the general theory in the text are included in this new edition.

  1. Threshold Ring Signature Scheme Based on TPM

    Institute of Scientific and Technical Information of China (English)

    Gong Bei; Jiang Wei; Lin Li; Li Yu; Zhang Xing

    2012-01-01

    The conventional ring signature schemes cannot address the scenario where the rank of members of the ring needs to be distinguished, for example, in electronically commerce application. To solve this problem, we presented a Trusted Platform Module (TPM)-based threshold ring signature schen. Employing a reliable secret Share Distribution Center (SDC), the proposed approach can authenticate the TPM-based identity rank of members of the ring but not track a specific member's identity. A subset including t members with the same identity rank is built. With the signing cooperation of t members of the subset, the ring signature based on Chinese remainder theorem is generated. We proved the anonymity and unforgeability of the proposed scheme and compared it with the threshold ring signature based on Lagrange interpolation polynomial. Our scheme is relatively simpler to calculate.

  2. Stable Bound Orbits around Black Rings

    Energy Technology Data Exchange (ETDEWEB)

    Igata, Takahisa; Ishihara, Hideki; Takamori, Yohsuke, E-mail: igata@sci.osaka-cu.ac.jp [Department of Mathematics and Physics, Graduate School of Science, Osaka City University, Osaka 558-8585 (Japan)

    2011-09-22

    We study stable bound orbits of a free particle around a black ring. Unlike the higher-dimensional black hole case, we find that there exist stable bound orbits in toroidal spiral shape near the ring axis and stable circular orbits on the axis. In addition, radii of stable bound orbits can be infinitely large if the ring thickness is less than a critical value.

  3. Inductive Rings and Systems of Diophantine Equations

    Institute of Scientific and Technical Information of China (English)

    Rong Fang BIE; Shi Qiang WANG

    2006-01-01

    In this paper, by using model-theoretic methods, it is shown that some systems of unsolved cubic diophantine equations in number theory can have solutions in certain inductive extension rings of the ring I of rational integers. These inductive rings are not fields, and every element of them is a sum of 4 cubes and a sum of 3 squares. Also some of them satisfy the Goldbach conjecture and some others don't.

  4. Good Gradings of Generalized Incidence Rings

    CERN Document Server

    Price, Kenneth L

    2011-01-01

    This inquiry is based on both the construction of generalized incidence rings due to Gene Abrams and the construction of good group gradings of incidence algebras due to Molli Jones. We provide conditions for a generalized incidence ring to be graded isomorphic to a subring of an incidence ring over a preorder. We also extend Jones's construction to good group gradings for incidence algebras over preorders with crosscuts of length one or two.

  5. Weakly and Strongly Regular Near-rings

    Institute of Scientific and Technical Information of China (English)

    N.Argac; N.J.Groenewald

    2005-01-01

    In this paper, we prove some basic properties of left weakly regular near-rings.We give an affirmative answer to the question whether a left weakly regular near-ring with left unity and satisfying the IFP is also right weakly regular. In the last section, we use among others left 0-prime and left completely prime ideals to characterize strongly regular near-rings.

  6. Braided rings a scattering billiard model

    CERN Document Server

    Bénet, L

    1999-01-01

    We introduce a billiard scattering model consisting of two non-overlapping rotating discs in the context of the formation and structural properties of planetary rings. We show that due to the arrangement of the symmetric periodic orbits, stable orbits are found which in the configuration space lead to the appearance of patterns qualitatively similar to planetary rings. Rings associated with different stability regions are naturally braided; different braids may overlap displaying features similar to clumps. Erosion mechanisms within the model are discussed.

  7. Saturn Ring Data Analysis and Thermal Modeling

    Science.gov (United States)

    Dobson, Coleman

    2011-01-01

    CIRS, VIMS, UVIS, and ISS (Cassini's Composite Infrared Specrtometer, Visual and Infrared Mapping Spectrometer, Ultra Violet Imaging Spectrometer and Imaging Science Subsystem, respectively), have each operated in a multidimensional observation space and have acquired scans of the lit and unlit rings at multiple phase angles. To better understand physical and dynamical ring particle parametric dependence, we co-registered profiles from these three instruments, taken at a wide range of wavelengths, from ultraviolet through the thermal infrared, to associate changes in ring particle temperature with changes in observed brightness, specifically with albedos inferred by ISS, UVIS and VIMS. We work in a parameter space where the solar elevation range is constrained to 12 deg - 14 deg and the chosen radial region is the B3 region of the B ring; this region is the most optically thick region in Saturn's rings. From this compilation of multiple wavelength data, we construct and fit phase curves and color ratios using independent dynamical thermal models for ring structure and overplot Saturn, Saturn ring, and Solar spectra. Analysis of phase curve construction and color ratios reveals thermal emission to fall within the extrema of the ISS bandwidth and a geometrical dependence of reddening on phase angle, respectively. Analysis of spectra reveals Cassini CIRS Saturn spectra dominate Cassini CIRS B3 Ring Spectra from 19 to 1000 microns, while Earth-based B Ring Spectrum dominates Earth-based Saturn Spectrum from 0.4 to 4 microns. From our fits we test out dynamical thermal models; from the phase curves we derive ring albedos and non-lambertian properties of the ring particle surfaces; and from the color ratios we examine multiple scattering within the regolith of ring particles.

  8. Report of the eRHIC Ring-Ring Working Group

    Energy Technology Data Exchange (ETDEWEB)

    Aschenauer, E. C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Berg, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brennan, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Fedotov, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Litvinenko, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Montag, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Palmer, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Parker, B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Peggs, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ptitsyn, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ranjbar, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tepikian, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trbojevic, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Willeke, F. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-10-13

    This report evaluates the ring-ring option for eRHIC as a lower risk alternative to the linac-ring option. The reduced risk goes along with a reduced initial luminosity performance. However, a luminosity upgrade path is kept open. This upgrade path consists of two branches, with the ultimate upgrade being either a ring-ring or a linac-ring scheme. The linac-ring upgrade could be almost identical to the proposed linac-ring scheme, which is based on an ERL in the RHIC tunnel. This linac-ring version has been studied in great detail over the past ten years, and its significant risks are known. On the other hand, no detailed work on an ultimate performance ring-ring scenario has been performed yet, other than the development of a consistent parameter set. Pursuing the ring-ring upgrade path introduces high risks and requires significant design work that is beyond the scope of this report.

  9. Simulation of Rings about Ellipsoidal Bodies

    Science.gov (United States)

    Gupta, Akash; Nadkarni-Ghosh, Sharvari; Sharma, Ishan

    2016-10-01

    Recent discovery of rings around Chariklo, a centaur orbiting the Sun (F. Braga-Ribas et al., 2014) and speculations of rings around minor planet, Chiron (Ortiz et al., 2015), Saturn's satellites, Rhea (Jones et al., 2008; Schenk et al., 2011), Iapetus (Ip, 2006) or exoplanets, suggest that rings about non-spherical bodies is perhaps a more general phenomenon than anticipated. As a first step towards understanding such systems, we examine the dynamical behavior of rings around similar bodies using N-body simulations. Our code employs the `local simulation method' (Wisdom & Tremaine, 1988; Salo, 1995) and accounts for particle interactions via collisions using Discrete Element Method (Cundall & Strack, 1978; Bhateja et al., 2016) and mutual gravitation. The central body has been modeled as an axisymmetric ellipsoid characterized by its axis ratio, or defined via characteristic frequencies (circular, vertical and epicyclic frequency) representing the gravitational field of an axisymmetric body. We vary the central body's characterizing parameter and observe the change in various ring properties like the granular temperature, impact frequency, radial width and vertical thickness. We also look into the effect on ring properties upon variation in the size of the central body-ring system. Further, we investigate the role of characteristic frequencies in dictating the ring dynamics, and how this could help in qualitatively estimating the ring dynamics about any arbitrary central body with symmetry about the equatorial plane and the axis normal to it.

  10. What Perturbs the ggrdgr Rings of Uranus?

    Science.gov (United States)

    French, R G; Kangas, J A; Elliot, J L

    1986-01-31

    The gamma and delta rings have by far the largest radial perturbations of any of the nine known Uranian rings. These two rings deviate from Keplerian orbits, having typical root-mean-square residuals of about 3 kilometers (compared to a few hundred meters for the other seven known rings). Possible causes for the perturbations include nearby shepherd satellites and Lindblad resonances. If shepherd satellites are responsible, they could be as large as several tens of kilometers in diameter. The perturbation patterns of the gamma and delta rings have been examined for evidence of Lindblad resonances of azimuthal wave number m = 0, 1, 2, 3, and 4. The beta ring radial residuals are well matched by a 2:1 Lindblad resonance. If this represents a real physical phenomenon and is not an artifact of undersampling, then the most plausible interpretation is that there is an undiscovered satellite orbiting 76,522 +/- 8 kilometers from Uranus, with an orbital period of 15.3595 +/- 0.0001 hours and a radius of 75 to 100 kilometers. Such a satellite would be easily detected by the Voyager spacecraft when it encounters Uranus. The 2:1 resonance location is 41 +/- 9 kilometers inside the delta ring, which makes it unlikely that the resonance is due to a viscous instability within the ring. In contrast, no low-order Lindblad resonance matches the gamma ring perturbations, which are probably caused by one or more shepherd satellites large enough to be clearly visible in Voyager images. PMID:17776019

  11. Validation of a vortex ring wake model suited for aeroelastic simulations of floating wind turbines

    DEFF Research Database (Denmark)

    Vaal, J.B., de; Hansen, Martin Otto Laver; Moan, T.

    2014-01-01

    In order to evaluate aerodynamic loads on floating oshore wind turbines, advanced dynamic analysis tools are required. As a unied model that can represent both dynamic in ow and skewed in ow effects in it basic formulation, a wake model based on a vortex ring formulation is discussed. Such a mode...

  12. Capsular hook-assisted implantation of modified capsular tension ring.

    Science.gov (United States)

    Khokhar, Sudarshan; Gupta, Shikha; Nayak, Bhagabat; Gogia, Varun

    2016-01-01

    A 16-year-old boy presented with decrease of vision over a period of 2 years. On examination, he was diagnosed to have microspherophakia with lenticular myopia with secondary glaucoma in both eyes. He was treated by lens aspiration and two-point capsular support using a modified capsular tension ring (M-CTR) and capsular tension segment (CTS) sutured to the sclera along with implantation of a foldable intraocular lens inside the bag. Lens aspiration was performed without artificial capsular hook support of the bag, as the lens was soft and vitreous was formed. However, M-CTR rotation into the bag was fraught with repeated adherence of the advancing end of the M-CTR into the loose bag causing simultaneous rotation of the bag with the rotation of the ring resulting in transient increase in bag subluxation. Capsular hooks provided appropriate countertraction to the unsupported bag, thus facilitating easy insertion and rotation of the ring into the bag. PMID:27048263

  13. Concentric ring flywheel with hooked ring carbon fiber separator/torque coupler

    Science.gov (United States)

    Kuklo, Thomas C.

    1999-01-01

    A concentric ring flywheel with expandable separators, which function as torque couplers, between the rings to take up the gap formed between adjacent rings due to differential expansion between different radius rings during rotation of the flywheel. The expandable separators or torque couplers include a hook-like section at an upper end which is positioned over an inner ring and a shelf-like or flange section at a lower end onto which the next adjacent outer ring is positioned. As the concentric rings are rotated the gap formed by the differential expansion there between is partially taken up by the expandable separators or torque couplers to maintain torque and centering attachment of the concentric rings.

  14. Control of ring lasers by means of coupled cavities

    DEFF Research Database (Denmark)

    Buchhave, Preben; Abitan, Haim; Tidemand-Lichtenberg, Peter

    2000-01-01

    Variable phase coupling to an external ring is used to control a unidirectional ring laser. The observed behavior of the coupled rings is explained theoretically. We have found experimentally that by quickly changing the phase of the feedback from the external ring it is possible to Q-switch the...... ring laser. Also, at certain values of the phase of the feedback in the external ring, instabilities in the total system occur and oscillations arise in the ring laser....

  15. Mechanical support of a ceramic gas turbine vane ring

    Science.gov (United States)

    Shi, Jun; Green, Kevin E.; Mosher, Daniel A.; Holowczak, John E.; Reinhardt, Gregory E.

    2010-07-27

    An assembly for mounting a ceramic turbine vane ring onto a turbine support casing comprises a first metal clamping ring and a second metal clamping ring. The first metal clamping ring is configured to engage with a first side of a tab member of the ceramic turbine vane ring. The second metal clamping ring is configured to engage with a second side of the tab member such that the tab member is disposed between the first and second metal clamping rings.

  16. Advanced Ceramics

    International Nuclear Information System (INIS)

    The First Florida-Brazil Seminar on Materials and the Second State Meeting about new materials in Rio de Janeiro State show the specific technical contribution in advanced ceramic sector. The others main topics discussed for the development of the country are the advanced ceramic programs the market, the national technic-scientific capacitation, the advanced ceramic patents, etc. (C.G.C.)

  17. Low-emittance Storage Rings

    CERN Document Server

    Wolski, A

    2014-01-01

    The effects of synchrotron radiation on particle motion in storage rings are discussed. In the absence of radiation, particle motion is symplectic, and the beam emittances are conserved. The inclusion of radiation effects in a classical approximation leads to emittance damping: expressions for the damping times are derived. Then, it is shown that quantum radiation effects lead to excitation of the beam emittances. General expressions for the equilibrium longitudinal and horizontal (natural) emittances are derived. The impact of lattice design on the natural emittance is discussed, with particular attention to the special cases of FODO-, achromat- and theoretical-minimum-emittance-style lattices. Finally, the effects of betatron coupling and vertical dispersion (generated by magnet alignment and lattice tuning errors) on the vertical emittance are considered.

  18. Relations in the tautological ring

    CERN Document Server

    Pandharipande, R

    2011-01-01

    These notes cover our series of three lectures at Humboldt University in Berlin for the October 2010 conference "Intersection theory on moduli space" (organized by G. Farkas). The topic concerns relations among the kappa classes in the tautological ring of the moduli space of genus g curves. After a discussion of classical constructions in Wick form, we derive an explicit set of relations obtained from the virtual geometry of the moduli space of stable quotients. In a series of steps, the stable quotient relations are transformed to simpler and simpler forms. Our final result establishes a previously conjectural set of tautological relations proposed a decade ago by Faber-Zagier. The Faber-Zagier relations are defined using g and a single series in one variable with coefficients (6i)!/(3i)!(2i)!. Whether these relations span the complete set of relations among the kappa classes on the moduli space of genus g curves is an interesting question.

  19. On PMM Rings%关于PMM环

    Institute of Scientific and Technical Information of China (English)

    李忠华; 宋光天; 储诚浩

    2005-01-01

    The PMM rings are defined and studied in this paper.A ring R is called a PMM ring if for any ring S which is Morita similar to R,Mm(S) is isomorphic to Mn(R) for some n,m∈N. The following results are proved in this paper.A ring R is a PMM ring if and only if whenever given a progenerator P over R, there exist m,n∈N and some Picard progenerator Q over R such that Pm is isomorphic to Qn. PMM rings with VBN property are just T2-rings;and with IBN property are T1-rings.If R is a commutative PMM ring,then R is indecomposable and the Picard group of R is power divisible.In particular,a Dedekind domain R is a PMM ring if and only if the Picard group of R is power divisible.%定义了PMM环.环R称为PMM环,若对任何Morita相似于R的环S,存在m,n∈N,使得Mm(S)同构于Mn(R).证明了如下结果:环R是PMM环当且仅当任给R的投射生成元P,存在m,n∈N以及R上的Picard投射生成元Q,使得Pm同构于Qn.具有VBN性质的PMM环是T2-环;具有IBN性质的PM环是T1-环.若交换环R是PMM环,则R是不可分解的且R的Picard群是幂可除的.特别地,Dedekind整环R是PMM环当且仅当R的Picard群是幂可除的.

  20. Influence of ring growth rate on damage development in hot ring rolling

    NARCIS (Netherlands)

    Wang, C.; Geijselaers, H.J.M.; Omerspahic, E.; Recina, V.; Boogaard, van den A.H.

    2016-01-01

    As an incremental forming process of bulk metal, ring rolling provides a cost effective process route to manufacture seamless rings. In the production of hot rolled rings, defects such as porosity can sometimes be found in high alloyed steel, manufactured from ingots having macro-segregation. For th

  1. VUV optical ring resonator for Duke storage ring free electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.H.; Litvinenko, V.N.; Madey, J.M.J. [Duke Univ., Durham, NC (United States)] [and others

    1995-12-31

    The conceptual design of the multifaceted-mirror ring resonator for Duke storage ring VUV FEL is presented. The expected performance of the OK-4 FEL with ring resonator is described. We discuss in this paper our plans to study reflectivity of VUV mirrors and their resistivity to soft X-ray spontaneous radiation from OK-4 undulator.

  2. The combined contraceptive vaginal ring (NuvaRing) and endometrial histology.

    NARCIS (Netherlands)

    Bulten, J.; Grefte, J.M.M.; Siebers, A.G.; Dieben, T.

    2005-01-01

    We investigated the effects of NuvaRing on endometrial histology in a 2-year open-label, multicenter trial in 103 premenopausal women aged 18-35 years. Subjects received 26 cycles of treatment, each comprising 3 weeks of ring use followed by a 1-week ring-free period. Endometrial biopsies were taken

  3. Catalytic ring opening of cyclic hydrocarbons in diesel fuels

    Energy Technology Data Exchange (ETDEWEB)

    Calemma, V.; Ferrari, M. [Eni S.p.A., San Donato Milanese (Italy). R and M Div.; Rabl, S.; Haas, A.; Santi, D.; Weitkamp, J. [Stuttgart Univ. (Germany). Inst. of Chemical Technology

    2013-11-01

    An approach for high-aromatic streams upgrading, allowing to meet future diesel quality standards, is saturation of the aromatic structures followed by the selective breaking of endocyclic C-C bonds of naphthenic structures so formed to produce alkanes with the same number of carbon atoms as the starting molecule ('selective ring opening, SRO'). Although theoretically, SRO is a promising route for upgrading low-value feeds to high-quality products, in practice, it continues to be a challenge owing to its complex chemistry. Product characteristics, do not only depend on the composition of the feed, but also on the operating conditions and the nature of the catalyst. Very recently, novel catalysts ('HIgh-PErformance Ring Opening Catalysts, HIPEROCs') were developed which allow a very selective ring opening of the model compound decalin to paraffins without degradation of the carbon number. The hydroconversion of dearomatized Light Cycle Oil (DeAr-LCO) over the abovementioned catalysts resulted in a remarkable change of the chemical structure of the feed with a strong decrease of naphthenic structures with two or more condensed rings and a concomitant increase of alkyl-substituted cyclohexanes and open-chain alkanes. The changes occurring in the chemical structures of feedstock during hydroconversion resulted in a remarkable increase of the Cetane Index of the products up to 11 units. In the present contribution, we examine the main factors affecting activity and selectivity of SRO catalysts in the light of the recent literature dealing with the subject and we report on the recent advances in hydroconversion of refinery cuts such as DeAr- LCO over HIPEROCs. (orig.)

  4. Vortex Ring Interaction with Multiple Permeable Screens

    Science.gov (United States)

    Musta, Mustafa N.; Krueger, Paul S.

    2008-11-01

    Previous experiments on the interaction of a vortex ring impinging on single thin permeable screen demonstrated the formation of secondary vortices and a transmitted vortex ring. The present work concerns experimental investigation of the interaction of a vortex ring with multiple permeable screens. Vortex rings are formed by piston-cylinder type vortex ring generator and impinge on an array of parallel, transparent screens. The screens have an open ratio of 84% and the spacing between screens is variable. The vortex rings were formed with an approximate jet Reynolds number of 1300 and a piston stroke-to-jet diameter ratio (L/D) of approximately 4. Dye visualization of the vortex rings shows that they break into multiple vortices after impinging on first screen The vortices subsequently disintegrate, but the total distance required for disintegration is relatively unaffected by the number of screens through with the vortices pass due to the regular structure of the screens. It is also observed that the location of the initial vortex ring axis relative to the screen rods has a significant effect on the vortex breakup and disintegration process.

  5. Pulsed magnetic field distribution near conducting rings

    International Nuclear Information System (INIS)

    Measurements and calculations of the magnetic field distribution in the vicinity of stainless steel rings immersed in a pulsed magnetic field are compared. The computer code TRIDIF is found to produce results in good agreement with the measurements. The perturbations in magnetic field due to the rings are found to be considerably less than one would expect from one-dimensional skin depth considerations

  6. On the nonlinear modeling of ring oscillators

    KAUST Repository

    Elwakil, Ahmed S.

    2009-06-01

    We develop higher-order nonlinear models of three-stage and five-stage ring oscillators based on a novel inverter model. The oscillation condition and oscillation frequency are derived and compared to classical linear model analysis. Two important special cases for five-stage ring oscillators are also studied. Numerical simulations are shown. © 2009 World Scientific Publishing Company.

  7. Rank 2 fusion rings are complete intersections

    DEFF Research Database (Denmark)

    Andersen, Troels Bak

    We give a non-constructive proof that fusion rings attached to a simple complex Lie algebra of rank 2 are complete intersections.......We give a non-constructive proof that fusion rings attached to a simple complex Lie algebra of rank 2 are complete intersections....

  8. On Polynomial Functions over Finite Commutative Rings

    Institute of Scientific and Technical Information of China (English)

    Jian Jun JIANG; Guo Hua PENG; Qi SUN; Qi Fan ZHANG

    2006-01-01

    Let R be an arbitrary finite commutative local ring. In this paper, we obtain a necessary and sufficient condition for a function over R to be a polynomial function. Before this paper, necessary and sufficient conditions for a function to be a polynomial function over some special finite commutative local rings were obtained.

  9. Ideals in Polynomial Near-rings

    Institute of Scientific and Technical Information of China (English)

    Mark Farag

    2002-01-01

    In this paper, we further explore the relationship between the ideals of N and those of N[x], where N is a zero-symmetric right near-ring with identity and N[x] is the polynomial near-ring introduced by Bagley in 1993.

  10. Local Duality for 2-Dimensional Local Ring

    Indian Academy of Sciences (India)

    Belgacem Draouil

    2008-11-01

    We prove a local duality for some schemes associated to a 2-dimensional complete local ring whose residue field is an -dimensional local field in the sense of Kato–Parshin. Our results generalize the Saito works in the case =0 and are applied to study the Bloch–Ogus complex for such rings in various cases.

  11. C and C* among intermediate rings

    NARCIS (Netherlands)

    J. Sack; S. Watson

    2013-01-01

    Given a completely regular Hausdorff space X, an intermediate ring A(X) is a ring of real valued continuous functions between C*(X) and C(X). We discuss two correspondences between ideals in A(X) and z-filters on X, both reviewing old results and introducing new results. One correspondence, ZA, exte

  12. On Hochschild cohomology rings of Fibonacci algebras

    Institute of Scientific and Technical Information of China (English)

    FAN Jinmei; XU Yunge

    2006-01-01

    Let A be a Fibonacci algebra over a field k.The multiplication of Hochschild cohomology ring of A induced by the Yoneda product is described explicitly.As a consequence,the multiplicative structure of Hochschild cohomology ring of A is proved to be trivial.

  13. Dieudonn\\'e theory over semiperfect rings

    OpenAIRE

    Lau, Eike

    2016-01-01

    The Dieudonn\\'e crystal of a p-divisible group over a semiperfect ring R can be endowed with a window structure. If R satisfies a boundedness condition, this construction gives an equivalence of categories. As an application one obtains a classification of p-divisible groups over arbitrary perfectoid rings by Breuil-Kisin modules.

  14. Let Freedom Ring! Bulletin, 1937, No. 32

    Science.gov (United States)

    Calhoun, Harold G.; Calhoun, Dorothy; Hatch, Roy W.; Cohen, Philip H.; Schramm, Rudolf

    1937-01-01

    This volume of "Let Freedom Ring!" contains the scripts of the 13 national broadcasts of the radio series of that name presented in the spring of 1937 over the national network of the Columbia Broadcast System. In "Let Freedom Ring!" you will find the courage, the struggle, the triumph of men and women who fought to win and safeguard liberties…

  15. Fuzzy Rough Ring and Its Prop erties

    Institute of Scientific and Technical Information of China (English)

    REN Bi-jun; FU Yan-ling

    2013-01-01

    This paper is devoted to the theories of fuzzy rough ring and its properties. The fuzzy approximation space generated by fuzzy ideals and the fuzzy rough approximation operators were proposed in the frame of fuzzy rough set model. The basic properties of fuzzy rough approximation operators were analyzed and the consistency between approximation operators and the binary operation of ring was discussed.

  16. Giant Rings in the CMB Sky

    CERN Document Server

    Kovetz, Ely D; Itzhaki, Nissan

    2010-01-01

    We find a unique direction in the CMB sky around which giant rings have an anomalous mean temperature profile. This direction is in very close alignment with the afore measured anomalously large bulk flow direction. We argue that a cosmic defect seeded by a pre-inflationary particle could explain the giant rings, the large bulk flow and their alignment.

  17. Prometheus Induced Vorticity In Saturns F Ring

    CERN Document Server

    Sutton, Phil J

    2016-01-01

    Saturns rings are known to show remarkable real time variability in their structure. Many of which can be associated to interactions with nearby moons and moonlets. Possibly the most interesting and dynamic place in the rings, probably in the whole Solar System, is the F ring. A highly disrupted ring with large asymmetries both radially and azimuthally. Numerically non zero components to the curl of the velocity vector field (vorticity) in the perturbed area of the F ring post encounter are witnessed, significantly above the background vorticity. Within the perturbed area rich distributions of local rotations is seen located in and around the channel edges. The gravitational scattering of ring particles during the encounter causes a significant elevated curl of the vector field above the background F ring vorticity for the first 1-3 orbital periods post encounter. After 3 orbital periods vorticity reverts quite quickly to near background levels. This new found dynamical vortex life of the ring will be of grea...

  18. A ring burn--electric or contact?

    Science.gov (United States)

    Attalla, M F; el-Ekiabi, S; Al-Baker, A

    1990-02-01

    A circumferential band of deep burn affecting the ring finger sustained by a car electrician is presented. Although it was caused by short circuiting the car battery by a metal spanner and the ring he was wearing, the injury was purely a contact burn. PMID:2322399

  19. Highest Weight Categories For Number Rings

    CERN Document Server

    Pilkington, Annette

    2011-01-01

    This paper examines the concept of a stratified exact category in the context of number rings and corresponding Galois groups. BGG reciprocity and duality are proven for these categories making them highest weight categories. The strong connections between the structure of the category and ramification in the ring are explored.

  20. New Horizons Imaging of Jupiter's Main Ring

    Science.gov (United States)

    Throop, Henry B.; Showalter, Mark Robert; Dones, Henry C. Luke; Hamilton, D. P.; Weaver, Harold A.; Cheng, Andrew F.; Stern, S. Alan; Young, Leslie; Olkin, Catherine B.; New Horizons Science Team

    2016-10-01

    New Horizons took roughly 520 visible-light images of Jupiter's ring system during its 2007 flyby, using the spacecraft's Long-Range Reconnaissance Imager (LORRI). These observations were taken over nine days surrounding Jupiter close-approach. They span a range in distance of 30 - 100 RJ, and a phase angle range of 20 - 174 degrees. The highest resolution images -- more than 200 frames -- were taken at a resolution approaching 20 km/pix.We will present an analysis of this dataset, much of which has not been studied in detail before. Our results include New Horizons' first quantitative measurements of the ring's intrinsic brightness and variability. We will also present results on the ring's azimuthal and radial structure. Our measurements of the ring's phase curve will be used to infer properties of the ring's dust grains.Our results build on the only previous analysis of the New Horizons Jupiter ring data set, presented in Showalter et al (2007, Science 318, 232-234), which detected ring clumps and placed a lower limit on the population of undetected ring-moons.This work was supported by NASA's OPR program.

  1. Flexible Twin Open Ring Metro WDM Network

    Institute of Scientific and Technical Information of China (English)

    Susumu Kinoshita; Cechan Tian; Satoru Ohdate; Koji Takeguchi; Yasuhiko Aoki

    2003-01-01

    We have demonstrated a flexible twin open ring WDM network for metro applications. A pair of optical switches in the network keeps the fiber rings open to prevent signal circulation. Traffics are broadcast to every node and selected at the receiving side. Superior transmission and protection switching are proved.

  2. Interactions between unidirectional quantized vortex rings

    CERN Document Server

    Zhu, T; Brown, R A; Walmsley, P M; Golov, A I

    2016-01-01

    We have used the vortex filament method to numerically investigate the interactions between pairs of quantized vortex rings that are initially traveling in the same direction but with their axes offset by a variable impact parameter. The interaction of two circular rings of comparable radii produce outcomes that can be categorized into four regimes, dependent only on the impact parameter; the two rings can either miss each other on the inside or outside, or they can reconnect leading to final states consisting of either one or two deformed rings. The fraction of of energy went into ring deformations and the transverse component of velocity of the rings are analyzed for each regime. We find that rings of very similar radius only reconnect for a very narrow range of the impact parameter, much smaller than would be expected from geometrical cross-section alone. In contrast, when the radii of the rings are very different, the range of impact parameters producing a reconnection is close to the geometrical value. A...

  3. Ethinyl Estradiol and Etonogestrel Vaginal Ring

    Science.gov (United States)

    ... cervix (opening of the uterus) to prevent sperm (male reproductive cells) from entering. The contraceptive ring is a very effective method of birth ... will help you choose a method, such as male condoms and/or spermicides. You ... not use a diaphragm when a contraceptive ring is in place.You do not need ...

  4. Non-commutative Modal Rings and Internalized Equality

    Institute of Scientific and Technical Information of China (English)

    D. Fearnley-Sander; A.V. Kelarev; T. Stokes

    2002-01-01

    We generalize the notion of modal Boolean rings to rings in general. The connection between Boolean rings with equality and modal Boolean rings provides a cue for the definition. The main motivation lies in the existence of examples such as matrix and polynomial rings over modal Boolean rings and Cartesian products of associative rings with identity, along with the desire that the class of "modal rings" be closed under formation of not only the usual homomorphic image, subalgebra and direct product constructions, but also the ring-theoretic constructions of forming matrices and polynomials.

  5. ATOMIC FORCE MICROSCOPY STUDIES OF POLYCAPROLACTONE RINGED SPHERULITES

    Institute of Scientific and Technical Information of China (English)

    Jian-bin Zhang; De-zhu Ma; Hua Zhong; Xiao-lie Luo

    2000-01-01

    The surface morphology of free-surface PCL ringed spherulites was investigated by using atomic force microscopy. The spherulites were obtained by crystallization of PCL/PVC blends of different compositions. It was found that the ringed spherulite exhibited regularly fluctuating rings on its surface. Compared with the bright-dark ring pattern of the spherulite under a polarizing microscope, it was proved that the optical characteristics of the ringed spherulite under polarizing microscope coincided with its surface characteristics. The bright rings in polarizing micrographs of the spherulite coincided with the convex rings on its surface, while the dark rings coincided with the concave rings.

  6. Process Design by FEM Simulation for Shape Ring Rolling of Large-Sized Ring

    Science.gov (United States)

    Lee, Y. S.; Lee, M. W.; Park, S. S.; Lee, I.; Moon, Y. H.

    2010-06-01

    Ring rolling process is usually used to fabricate large-sized ring, such as, tower flange for wind power electric generator. Many kinds of seamless ring are used in wind power electric generator and manufactured by ring rolling process. In general, final part is machined after forming with shape of plain square section. Since interests for near net shaping of seamless ring have been increased gradually because of green energy, it is necessary to develop the technology for shape ring rolling with respect to the market demands and cost. Therefore, we studied the process and die design for shape ring rolling of large sized ring over 3,500 mm out diameter by experiment and FEM simulation. Ring rolling process is very difficult to solve by FEM method because of equilibrium state and size effect, etc. Moreover, shape ring rolling is more difficult to solve the problem that two plastic deformation zones are different each other, that is main roll and conical roll. Also since conical roll has a shape, deformation velocity field is very much complex and the deformed section passed axial roll is different section and velocity field. The FE simulations are performed to analyze process variables affected in forming of profiled ring. Therefore, the main features of used FE model are: (1) it adopts a transient or unsteady state full ring mesh to model the deformation processes and shape development; (2) the mandrel and conical rolls are modeled using coupled heat-transfer elements; (3) the model involves the full process from blank through perform to final profiled ring. From these calculated results, we have proposed the mechanisms of various tools, such as mandrel and conical roll. The calculated results are compared experimental results. Calculated results can predict the tilting of profiled ring and then process variables to form large sized ring.

  7. Radiation from structured-ring resonators

    CERN Document Server

    Maling, B; Craster, R V

    2016-01-01

    We investigate the scalar-wave resonances of systems composed of identical Neumann-type inclusions arranged periodically around a circular ring. Drawing on natural similarities with the undamped Rayleigh-Bloch waves supported by infinite linear arrays, we deduce asymptotically the exponentially small radiative damping in the limit where the ring radius is large relative to the periodicity. In our asymptotic approach, locally linear Rayleigh-Bloch waves that attenuate exponentially away from the ring are matched to a ring-scale WKB-type wave field. The latter provides a descriptive physical picture of how the mode energy is transferred via tunnelling to a circular evanescent-to-propagating transition region a finite distance away from the ring, from where radiative grazing rays emanate to the far field. Excluding the zeroth-order standing-wave modes, the position of the transition circle bifurcates with respect to clockwise and anti-clockwise contributions, resulting in striking spiral wavefronts.

  8. Hidden Beauty in Twisted Viking Neck Rings

    CERN Document Server

    Olsen, Kasper

    2010-01-01

    Many hoards found in Ireland, Scotland, Orkney Islands, and Scandinavia demonstrate the vikings ability to fabricate beautiful arm and neck rings of twisted silver and gold rods. Characteristic for such rings is the uniform appearance of the twisted pattern along the length of the arm ring, as well as from one arm ring to another, also when found at distant geographical locations. How can the appearance of the twisted wires be so perfectly repetitive? We demonstrate that the answer is that the vikings utilized a self-forming motif: The pattern arises from a twisting of the wires to a maximally rotated configuration. That is why the twist patterns in these arm and neck rings are beautiful, repetitive, and universal.

  9. The rings of Uranus - Nature and origin

    Science.gov (United States)

    Dermott, S. F.; Gold, T.; Sinclair, A. T.

    1979-01-01

    Effects of a resonance between a set of ring particles and individual satellites are considered. It is suggested that the resonances are 1:1 for the rings of Uranus and that each ring must contain an as-yet unseen satellite. A model is proposed in which the rings of Uranus were caused by small satellites that entered the Roche zone due to tidal drag. According to this model, the satellites gradually lost material from their surfaces in this zone, the particles left a satellite with relatively low speeds and must have entered orbits similar to that of the satellite, and the gravitational force of the satellite compelled these particles to remain in a narrow sharply defined ring.

  10. A topologically driven glass in ring polymers

    Science.gov (United States)

    Michieletto, Davide

    2016-05-01

    The static and dynamic properties of ring polymers in concentrated solutions remains one of the last deep unsolved questions in polymer physics. At the same time, the nature of the glass transition in polymeric systems is also not well understood. In this work, we study a novel glass transition in systems made of circular polymers by exploiting the topological constraints that are conjectured to populate concentrated solutions of rings. We show that such rings strongly interpenetrate through one another, generating an extensive network of topological interactions that dramatically affects their dynamics. We show that a kinetically arrested state can be induced by randomly pinning a small fraction of the rings. This occurs well above the classical glass transition temperature at which microscopic mobility is lost. Our work both demonstrates the existence of long-lived inter-ring penetrations and realizes a novel, topologically induced, glass transition.

  11. Interdigitated ring electrodes: Theory and experiment

    CERN Document Server

    Barnes, Edward O; Pozo-Ayuso, Diego F; Castaño-Alvarez, Mario; Lewis, Grace E M; Dale, Sara E C; Marken, Frank; Compton, Richard G

    2013-01-01

    The oxidation of potassium ferrocyanide, K_4Fe(CN)_6, in aqueous solution under fully supported conditions is carried out at interdigitated band and ring electrode arrays, and compared to theoretical models developed to simulate the processes. Simulated data is found to fit well with experimental results using literature values of diffusion coefficients for Fe(CN)_6^(4-) and Fe(CN)_6^(3-). The theoretical models are used to compare responses from interdigitated band and ring arrays, and the size of ring array required to approximate the response to a linear band array is investigated. An equation is developed for the radius of ring required for a pair of electrodes in a ring array to give a result with 5% of a pair of electrodes in a band array. This equation is found to be independent of the scan rate used over six orders of magnitude.

  12. 46 CFR 117.70 - Ring life buoys.

    Science.gov (United States)

    2010-10-01

    ... the body of the ring life buoy. (3) Each floating waterlight installed after March 11, 1997, on a... 46 Shipping 4 2010-10-01 2010-10-01 false Ring life buoys. 117.70 Section 117.70 Shipping COAST... Ring Life Buoys and Life Jackets § 117.70 Ring life buoys. (a) A vessel must have one or more ring...

  13. Tandem Ring-Opening-Ring-Closing Metathesis for Functional Metathesis Catalysts.

    Science.gov (United States)

    Nagarkar, Amit A; Yasir, Mohammad; Crochet, Aurelien; Fromm, Katharina M; Kilbinger, Andreas F M

    2016-09-26

    Use of a tandem ring-opening-ring-closing metathesis (RORCM) strategy for the synthesis of functional metathesis catalysts is reported. Ring opening of 7-substituted norbornenes and subsequent ring-closing metathesis forming a thermodynamically stable 6-membered ring lead to a very efficient synthesis of new catalysts from commercially available Grubbs' catalysts. Hydroxy functionalized Grubbs' first- as well as third-generation catalysts have been synthesized. Mechanistic studies have been performed to elucidate the order of attack of the olefinic bonds. This strategy was also used to synthesize the ruthenium methylidene complex. PMID:27592840

  14. Tandem Ring-Opening-Ring-Closing Metathesis for Functional Metathesis Catalysts.

    Science.gov (United States)

    Nagarkar, Amit A; Yasir, Mohammad; Crochet, Aurelien; Fromm, Katharina M; Kilbinger, Andreas F M

    2016-09-26

    Use of a tandem ring-opening-ring-closing metathesis (RORCM) strategy for the synthesis of functional metathesis catalysts is reported. Ring opening of 7-substituted norbornenes and subsequent ring-closing metathesis forming a thermodynamically stable 6-membered ring lead to a very efficient synthesis of new catalysts from commercially available Grubbs' catalysts. Hydroxy functionalized Grubbs' first- as well as third-generation catalysts have been synthesized. Mechanistic studies have been performed to elucidate the order of attack of the olefinic bonds. This strategy was also used to synthesize the ruthenium methylidene complex.

  15. Semi-algebraic function rings and reflectors of partially ordered rings

    CERN Document Server

    Schwartz, Niels

    1999-01-01

    The book lays algebraic foundations for real geometry through a systematic investigation of partially ordered rings of semi-algebraic functions. Real spectra serve as primary geometric objects, the maps between them are determined by rings of functions associated with the spectra. The many different possible choices for these rings of functions are studied via reflections of partially ordered rings. Readers should feel comfortable using basic algebraic and categorical concepts. As motivational background some familiarity with real geometry will be helpful. The book aims at researchers and graduate students with an interest in real algebra and geometry, ordered algebraic structures, topology and rings of continuous functions.

  16. Advanced positron sources

    Energy Technology Data Exchange (ETDEWEB)

    Variola, A., E-mail: variola@lal.in2p3.fr

    2014-03-11

    Positron sources are a critical system for the future lepton colliders projects. Due to the large beam emittance at the production and the limitation given by the target heating and mechanical stress, the main collider parameters fixing the luminosity are constrained by the e{sup +} sources. In this context also the damping ring design boundary conditions and the final performance are given by the injected positron beam. At present different schemes are being taken into account in order to increase the production and the capture yield of the positron sources, to reduce the impact of the deposited energy in the converter target and to increase the injection efficiency in the damping ring. The final results have a strong impact not only on the collider performance but also on its cost optimization. After a short introduction illustrating their fundamental role, the basic positron source scheme and the performance of the existing sources will be illustrated. The main innovative designs for the future colliders advanced sources will be reviewed and the different developed technologies presented. Finally the positrons-plasma R and D experiments and the futuristic proposals for positron sources will reviewed.

  17. The cryogenic storage ring project

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, Robert von; Blaum, Klaus; Becker, Arno; Fellenberger, Florian; George, Sebastian; Grieser, Manfred; Grussie, Florian; Herwig, Philipp; Krantz, Claude; Kreckel, Holger; Lange, Michael; Menk, Sebastian; Repnow, Roland; Vogel, Stephen; Wolf, Andreas [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Spruck, Kaija [Justus-Liebig-Universitaet, Giessen (Germany)

    2014-07-01

    At MPIK the electrostatic cryogenic storage ring CSR is nearing completion. At beam energies of 20 to 300 keV per charge unit and 35 m circumference the CSR will allow experiments in a cryogenic environment providing conditions of extremely low vacuum and heat radiation. By using liquid helium at 2 K for cryopumping, the projected vacuum (confirmed at a prototype) lies at 1E-13 mbar or below, ensuring long storage times for slow singly charged and highly charged ions, molecules and clusters. Moreover, phase space cooling by electrons will be implemented. The internal quantum states of molecular and cluster ions can be cooled to low temperature, yielding well defined vibrational and for smaller systems also rotational structures. In the CSR construction, the cryogenic ion beam vacuum system has been set up. Extensive tests confirming the criteria on heat flow, alignment and high-voltage stability were successfully completed on the first quadrant. In addition beam diagnostic units for electric pickup signals and spatial profiles, detectors for neutral and charged fragments, the injection beam line, and an electron cooling device are under construction.

  18. ring av erfaring?

    DEFF Research Database (Denmark)

    Ramvi, Ellen

    Hva skal til for å lære av erfaring? Denne avhandlingen er en empirisk baseret undersøkelse av ungdosmskolelæreres muligheter og betingelser for å "lære av erfaring" i den særlige betydning av begrepet  W. Bion gir i sin psykoanalytiske teori. Undersøgelsen baserer seg på et feltarbeid som strekker...... seg over ett skoleår. Datamaterialet ble samlet inn via observerasjoner og mer eller mindre strukturerte samtaler med lærere ved to forskellige norske ungdsomsskoler. Analysen av materialet foregår i to trinn: først en fenomenologisk analyse, tett på lærernes egne beskrivelser og refleksjoner av...... lærerarbeidet, dets udfordringer og vanskeligheter, og deretter en psykoanalytisk perspektivering av de fenomenologiske analyseresultatene. Analysen viser en almindelig lærerhverdag og en skoleorganisation, hvor lærernes "læring av erfaring" i stor utstrekning blokkeres i et vekselspill mellem lærernes flukt...

  19. Advance care directives

    Science.gov (United States)

    ... advance directive; Do-not-resuscitate - advance directive; Durable power of attorney - advance care directive; POA - advance care directive; Health care agent - advance care directive; Health care proxy - ...

  20. Estimating the mass of Saturn's B ring

    Science.gov (United States)

    Hedman, Matthew M.; Nicholson, Philip D.

    2016-10-01

    The B ring is the brightest and most opaque of Saturn's rings, but it is also amongst the least well understood because basic parameters like its surface mass density have been poorly constrained. Elsewhere in the rings, spiral density waves driven by resonances with Saturn's various moons provide precise and robust mass density estimates, but for most the B ring extremely high opacities and strong stochastic optical depth variations obscure the signal from these wave patterns. We have developed a new wavelet-based technique that combines data from multiple stellar occultations (observed by the Visual and Infrared Mapping Spectrometer instrument onboard the Cassini spacecraft) that has allowed us to identify signals that appear to be due to waves generated by the strongest resonances in the central and outer B ring. These wave signatures yield new estimates of the B-ring's mass density and indicate that the B-ring's total mass could be quite low, between 1/3 and 2/3 the mass of Saturn's moon Mimas.

  1. Magnetization reversal in arrays of Co rings

    Science.gov (United States)

    Welp, U.; Vlasko-Vlasov, V. K.; Hiller, J. M.; Zaluzec, N. J.; Metlushko, V.; Ilic, B.

    2003-08-01

    The magnetization behavior of arrays of individual and coupled Co rings has been studied using superconducting quantum interference device magnetometry, magneto-optical imaging, and Lorentz transmission and scanning transmission electron microscopy. The transition from the polarized into the vortex state of isolated rings is shown to occur through the motion and annihilation of head-to-head domain boundaries. The chirality of the vortex state is fixed on subsequent magnetization cycles, indicating that it is predetermined by structural imperfections of the rings. The effect of interactions between the rings has been investigated in arrays of chains of touching rings. For fields applied parallel to the chains rings in extended sections of the chains are found to switch simultaneously. Neighboring rings in these sections can display alternating chirality as well as the same chirality accompanied by a 180° boundary on the nodes. For fields perpendicular to the chain direction the switching occurs pairwise. This coupling introduces a broad distribution of switching fields and correspondingly a magnetization curve that is significantly broader than that for the parallel orientation.

  2. Microstructural heterogeneity of forged rolled rings

    Directory of Open Access Journals (Sweden)

    J. Herian

    2007-04-01

    Full Text Available Purpose: The paper presents the processes which condition the quality of steel cast strands and properties of rolled products. It touches upon the technology of small-size rings manufacture from the 42CrMo4 steel used for the production of rolling bearings and toothed rings.Design/methodology/approach: Investigations were made on the 42CrMo4 steel based process of small-size rings manufacture of weight not exceeding 100 kg and the internal diameter up to 600 mm.Findings: Microstructure heterogeneity has been proven on the cross section of rods and rings under hot rolling and thermal treatment. Non-uniformity in hardness distribution was found on the hot rolled rings’ face surface and cross section. Final products made from rings with heterogeneous properties characterize: difficulties with machining, cracking during surface hardening and decrease of life time. After the process modification, the rings’ microstructure homogeneity and advantageous hardness distribution were obtained.Practical implications: A good quality of final rings after heat treatment is obtained in the case of charge characterized by a uniform pearlitic/ferritic microstructure. After the process technology modification, the rings’ microstructure homogeneity and advantageous hardness distribution were obtained.Originality/value: The minimum processing degree in the rolling of rod products should guarantee obtaining a homogeneous microstructure on the rings cross section and properties which would ensure a good quality and the required functional properties of the final products.

  3. Vortex Ring Interaction with a Heated Screen

    Science.gov (United States)

    Smith, Jason; Krueger, Paul S.

    2008-11-01

    Previous examinations of vortex rings impinging on porous screens has shown the reformation of the vortex ring with a lower velocity after passing through the screen, the creation of secondary vortices, and mixing. A heated screen could, in principle, alter the vortex-screen interaction by changing the local liquid viscosity and density. In the present investigation, a mechanical piston-cylinder vortex ring generator was used to create vortex rings in an aqueous sucrose solution. The rings impinged on a screen of horizontal wires that were heated using electrical current. The flow was visualized with food color and video imaging. Tests with and without heat were conducted at a piston stroke-to-jet diameter ratio of 4 and a jet Reynolds number (Re) of 1000. The vortex rings slowed after passing through the screen, but in tests with heat, they maintained a higher fraction of their before-screen velocity due to reduction in fluid viscosity near the wires. In addition, small ``fingers'' that developed on the front of the vortex rings as they passed through the screen exhibited positive buoyancy effects in the heated case.

  4. Design for ANL 7 GeV storage ring vacuum system

    International Nuclear Information System (INIS)

    The 7-GeV Advanced Photon Source (APS) design includes a storage ring having a 1060-m circumference with the capability of accommodating 34 insertion devices (ID) and their associated photon beam lines. An additional 35 photon lines can be provided from bending magnets. The vacuum system for the storage ring is designed to maintain a beam-on operating pressure of 1n Torr or less to achieve a positron beam lifetime of approximately 20 hours. The vacuum system and it's current developmental status are described

  5. Weakly Dual Rings%弱对偶环

    Institute of Scientific and Technical Information of China (English)

    WEI Jun-chao; SUN Jian-hua

    2004-01-01

    In This paper, the concept of weakly dual ring is introduced, which is a proper generalization of the dual ring. IfR is a right weakly dual ring, then (1) Z(RR) = J(R); (2) If R is also a zero-division power ring, then R is a right Apinjective ring. In addition, some properties of weakly dual rings are given.

  6. A census of Gulf Stream rings, spring 1975

    Science.gov (United States)

    Richardson, P. L.; Worthington, L. V.; Cheney, R. E.

    1978-01-01

    During 1975 several shipboard expendable bathythermograph surveys plus satellite infrared imagery provided a nearly synoptic view of the distribution and number of Gulf Stream rings in the western North Atlantic. Twelve rings were identified; nine were cyclonic (cold core) rings and three were anticyclonic (warm core) rings. This is the largest number of rings ever observed during a short period of time (4 months). Evidence suggests that the mean movement of these rings was southwestward.

  7. The Discrete Logarithm Problem in Bergman's non-representable ring

    OpenAIRE

    Banin, Matan; Tsaban, Boaz

    2012-01-01

    Bergman's Ring $E_p$, parameterized by a prime number $p$, is a ring with $p^5$ elements that cannot be embedded in a ring of matrices over any commutative ring. This ring was discovered in 1974. In 2011, Climent, Navarro and Tortosa described an efficient implementation of $E_p$ using simple modular arithmetic, and suggested that this ring may be a useful source for intractable cryptographic problems. We present a deterministic polynomial time reduction of the Discrete Logarithm Problem in $...

  8. Ideal-comparability over Regular Rings

    Institute of Scientific and Technical Information of China (English)

    Huan Yin CHEN; Miao Sen CHEN

    2006-01-01

    We introduce the concept of ideal-comparability condition for regular rings. Let I be an ideal of a regular ring R. If R satisfies the Ⅰ-comparability condition, then R is one-sided unit-regular if and only if so is R/I. Also, we show that a regular ring R satisfies the general comparability if and only if the following hold: (1) R/I satisfies the general comparability; (2) R satisfies the general Ⅰ-comparability condition; (3) The natural map B(R) → B(R/I) is surjective.

  9. Storage ring and laser nuclear spectroscopy

    International Nuclear Information System (INIS)

    Storage-ring technique is complementary to trapping-ion technique. A storage ring for energetic ions will enable us to study exotic phenomena, such as hydrogenic atoms and enhanced β-decay of 'bare nuclei'. A storage ring for low-energy ions is good for precise laser-nuclear spectroscopy. TARN-II is a kind of the former, and it is suggested that an extremely high magnetic field produced by a highly ionized atom gives us insight into nuclear magnetism if hyperfine anomaly is observed for such an atom. (author)

  10. Dipolar bosons on an optical lattice ring

    Energy Technology Data Exchange (ETDEWEB)

    Maik, Michal [Instytut Fizyki imienia Mariana Smoluchowskiego, Uniwersytet Jagiellonski, ulica Reymonta 4, PL-30-059 Krakow (Poland); Buonsante, Pierfrancesco [Dipartimento di Fisica, Universita degli Studi di Parma, Viale G.P. Usberti n.7/A, IT-43100 Parma (Italy); Vezzani, Alessandro [Centro S3, CNR Istituto di Nanoscienze, via Campi 213/a, IT-41100 Modena (Italy); Dipartimento di Fisica, Universita degli Studi di Parma, Viale G.P. Usberti n.7/A, 43100 Parma (Italy); Zakrzewski, Jakub [Instytut Fizyki imienia Mariana Smoluchowskiego, Uniwersytet Jagiellonski, ulica Reymonta 4, PL-30-059 Krakow (Poland); Mark Kac Complex Systems Research Center, Uniwersytet Jagiellonski, ulica Reymonta 4, PL-30-059 Krakow (Poland)

    2011-11-15

    We consider an ultrasmall system of polarized bosons on an optical lattice with a ring topology, interacting via long-range dipole-dipole interactions. Dipoles polarized perpendicular to the plane of the ring reveal sharp transitions between different density-wave phases. As the strength of the dipolar interactions is varied, the behavior of the transitions is first-order-like. For dipoles polarized in the plane of the ring, the transitions between possible phases show pronounced sensitivity to the lattice depth. The abundance of possible configurations may be useful for quantum-information applications.

  11. Classical sheaf cohomology rings on Grassmannians

    CERN Document Server

    Guo, Jirui; Sharpe, Eric

    2016-01-01

    Let the vector bundle $\\mathcal{E}$ be a deformation of the tangent bundle over the Grassmannian $G(k,n)$. We compute the ring structure of sheaf cohomology valued in exterior powers of $\\mathcal{E}$, also known as the polymology. This is the first part of a project studying the quantum sheaf cohomology of Grassmannians with deformations of the tangent bundle, a generalization of ordinary quantum cohomology rings of Grassmannians. A companion physics paper [arXiv:1512.08586] describes physical aspects of the theory, including a conjecture for the quantum sheaf cohomology ring, and numerous examples.

  12. Design of Piston Ring Friction Tester Apparatus

    DEFF Research Database (Denmark)

    Klit, Peder

    2006-01-01

    the frictional behavior of a piston ring correctly is knowledge about the amount of lubricant present. For piston rings the external load may be established by measuring the pressure distribution, i.e. the pressure drop in the piston ring package. Speed and temperature may also be established. The amount...... and forces on piston rod. Since the frictional forces are small compared to the rest of the acting forces the main design idea is to fix the piston, while the cylinder liner moves. This approach makes it simple to measure the parameters mentioned above by putting the instrumentation in the piston....

  13. Magnetic Bloch oscillations in nanowire superlattice rings.

    Science.gov (United States)

    Citrin, D S

    2004-05-14

    The recent growth of semiconductor nanowire superlattices encourages hope that Bloch-like oscillations in such structures formed into rings may soon be observed in the presence of a time-dependent magnetic flux threading the ring. These magnetic Bloch oscillations are a consequence of Faraday's law; the time-dependent flux produces an electromotive force around the ring, thus leading to the Bloch-like oscillations. In the spectroscopic domain, generalized Wannier-Stark states are found that are manifestations of the emf-induced localization of the states.

  14. Injection envelope matching in storage rings

    International Nuclear Information System (INIS)

    The shape and size of the transverse phase space injected into a storage ring can be deduced from turn-by-turn measurements of the transient behavior of the beam envelope in the ring. Envelope oscillations at 2 x the β-tron frequency indicate the presence of a β-mismatch, while envelope oscillations at the β-tron frequency are the signature of a dispersion function mismatch. Experiments in injection optimization using synchrotron radiation imaging of the beam and a fast-gated camera at the SLC damping rings are reported

  15. Molecular Model of the Contractile Ring

    CERN Document Server

    Biron, D; Tlusty, Tsvi; Moses, Elisha; 10.1103/PhysRevLett.95.098102

    2010-01-01

    We present a model for the actin contractile ring of adherent animal cells. The model suggests that the actin concentration within the ring and consequently the power that the ring exerts both increase during contraction. We demonstrate the crucial role of actin polymerization and depolymerization throughout cytokinesis, and the dominance of viscous dissipation in the dynamics. The physical origin of two phases in cytokinesis dynamics ("biphasic cytokinesis") follows from a limitation on the actin density. The model is consistent with a wide range of measurements of the midzone of dividing animal cells.

  16. Introduction into Calculus over Division Ring

    OpenAIRE

    Kleyn, Aleks

    2008-01-01

    Based on twin representations of division ring in an Abelian group I consider $D$\\Hyph vector spaces over division ring. Morphism of $D$\\Hyph vector spaces is linear map of $D$\\Hyph vector spaces. I consider derivative of function $f$ of continuous division ring as linear map the most close to function $f$. I explore expansion of map into Taylor series and method to find solution of differential equation. The norm in $D$\\Hyph vector space allows considering of continuous mapping of $D$\\Hyph v...

  17. Linear recurring sequences over rings and modules

    Energy Technology Data Exchange (ETDEWEB)

    Kurakin, V.L.; Kuzmin, A.S.; Mikhalev, A.V. [and others

    1995-10-15

    Here we present some fundamental concept and results of the theory of linear recurring sequences over rings and modules and their applications. Of course, the authors give in more detail those results that are close to their mathematical interests. In particular, an attempt has been made to construct a general algebraic theory of k-LRS over modules, paying explicit attention to periodic k-sequences, to properties of linear recurrences over finite rings and especially over Galois rings, and also to methods of constructing codes baed on such recurrences.

  18. Dipolar bosons on an optical lattice ring

    Science.gov (United States)

    Maik, Michał; Buonsante, Pierfrancesco; Vezzani, Alessandro; Zakrzewski, Jakub

    2011-11-01

    We consider an ultrasmall system of polarized bosons on an optical lattice with a ring topology, interacting via long-range dipole-dipole interactions. Dipoles polarized perpendicular to the plane of the ring reveal sharp transitions between different density-wave phases. As the strength of the dipolar interactions is varied, the behavior of the transitions is first-order-like. For dipoles polarized in the plane of the ring, the transitions between possible phases show pronounced sensitivity to the lattice depth. The abundance of possible configurations may be useful for quantum-information applications.

  19. Future Synchrotron Light Sources Based on Ultimate Storage Rings

    International Nuclear Information System (INIS)

    The main purpose of this talk is to describe how far one might push the state of the art in storage ring design. The talk will start with an overview of the latest developments and advances in the design of synchrotron light sources based on the concept of an 'ultimate' storage ring. The review will establish how bright a ring based light source might be, where the frontier of technological challenges are, and what the limits of accelerator physics are. Emphasis will be given to possible improvements in accelerator design and developments in technology toward the goal of achieving an ultimate storage ring. An ultimate storage ring (USR), defined as an electron ring-based light source having an emittance in both transverse planes at the diffraction limit for the range of X-ray wavelengths of interest for a scientific community, would provide very high brightness photons having high transverse coherence that would extend the capabilities of X-ray imaging and probe techniques beyond today's performance. It would be a cost-effective, high-coherence 4th generation light source, competitive with one based on energy recovery linac (ERL) technology, serving a large number of users studying material, chemical, and biological sciences. Furthermore, because of the experience accumulated over many decades of ring operation, it would have the great advantage of stability and reliability. In this paper we consider the design of an USR having 10-pm-rad emittance. It is a tremendous challenge to design a storage ring having such an extremely low emittance, a factor of 100 smaller than those in existing light sources, especially such that it has adequate dynamic aperture and beam lifetime. In many ultra-low emittance designs, the injection acceptances are not large enough for accumulation of the electron beam, necessitating on-axis injection where stored electron bunches are completely replaced with newly injected ones. Recently, starting with the MAX-IV 7-bend achromatic cell, we

  20. Improving the Accuracy of Laplacian Estimation with Novel Variable Inter-Ring Distances Concentric Ring Electrodes

    Directory of Open Access Journals (Sweden)

    Oleksandr Makeyev

    2016-06-01

    Full Text Available Noninvasive concentric ring electrodes are a promising alternative to conventional disc electrodes. Currently, the superiority of tripolar concentric ring electrodes over disc electrodes, in particular, in accuracy of Laplacian estimation, has been demonstrated in a range of applications. In our recent work, we have shown that accuracy of Laplacian estimation can be improved with multipolar concentric ring electrodes using a general approach to estimation of the Laplacian for an (n + 1-polar electrode with n rings using the (4n + 1-point method for n ≥ 2. This paper takes the next step toward further improving the Laplacian estimate by proposing novel variable inter-ring distances concentric ring electrodes. Derived using a modified (4n + 1-point method, linearly increasing and decreasing inter-ring distances tripolar (n = 2 and quadripolar (n = 3 electrode configurations are compared to their constant inter-ring distances counterparts. Finite element method modeling and analytic results are consistent and suggest that increasing inter-ring distances electrode configurations may decrease the truncation error resulting in more accurate Laplacian estimates compared to respective constant inter-ring distances configurations. For currently used tripolar electrode configuration, the truncation error may be decreased more than two-fold, while for the quadripolar configuration more than a six-fold decrease is expected.

  1. The Advanced Photon Source list of parameters

    International Nuclear Information System (INIS)

    The Advanced Photon Source (APS) is a third-generation synchrotron radiation source that stores positrons in a storage ring. The choice of positrons as accelerating particles was motivated by the usual reason: to eliminate the degradation of the beam caused by trapping of positively charged dust particles or ions. The third-generation synchrotron radiation sources are designed to have low beam emittance and many straight sections for insertion devices. The parameter list is comprised of three basic systems: the injection system, the storage ring system, and the experimental facilities system. The components of the injection system are listed according to the causal flow of positrons. Below we briefly list the individual components of the injection system, with the names of people responsible for managing these machines in parentheses: the linac system; electron linac-target-positron linac (Marion White); low energy transport line from linac to the PAR (Michael Borland); positron accumulator ring or PAR (Michael Borland); low energy transport line from PAR to injector synchrotron (Michael Borland); injector synchrotron (Stephen Milton); high energy transport line from injector synchrotron to storage ring (Stephen Milton). The storage ring system, managed by Glenn Decker, uses the Chasman-Green lattice. The APS storage ring, 1104 m in circumference, has 40 periodic sectors. Six are used to house hardware and 34 serve as insertion devices. Another 34 beamlines emit radiation from bending magnets. The experimental facilities system's parameters include parameters for both an undulator and a wiggler

  2. Geodesic detection of Agulhas rings

    Science.gov (United States)

    Beron-Vera, F. J.; Wang, Y.; Olascoaga, M. J.; Goni, G. J.; Haller, G.

    2012-12-01

    Mesoscale oceanic eddies are routinely detected from instantaneous velocities. While simple to implement, this Eulerian approach gives frame-dependent results and often hides true material transport by eddies. Building on the recent geodesic theory of transport barriers, we develop an objective (i.e., frame-independent) method for accurately locating coherent Lagrangian eddies. These eddies act as compact water bodies, with boundaries showing no leakage or filamentation over long periods of time. Applying the algorithm to altimetry-derived velocities in the South Atlantic, we detect, for the first time, Agulhas rings that preserve their material coherence for several months, while eddy candidates yielded by other approaches tend to disperse or leak within weeks. These findings suggest that current Eulerian estimates of the Agulhas leakage need significant revision.Temporal evolution of fluid patches identified as eddies by different methods. First column: eddies extracted using geodesic eddy identification [1,2]. Second column: eddies identified from sea surface height (SSH) using the methodology of Chelton et al. [2] with U/c > 1. Third column: eddies identified as elliptic regions by the Okubo-Weiss (OW) criterion [e.g., 3]. Fourth column: eddies identified as mesoelliptic (ME) regions by Mezic et al.'s [4] criterion. References: [1] Beron-Vera et al. (2012). Geodesic eddy detection suggests reassessment of Agulhas leakage. Proc. Nat. Acad. Sci. USA, submitted. [2] Haller & Beron-Vera (2012). Geodesic theory of transport barriers in two-dimensional flows. Physica D, in press. [2] Chelton et al. (2011). Prog. Oceanog. 91, 167. [3] Chelton et al. (2007). Geophys. Res. Lett. 34, L5606. [4] Mezic et al. (2010). Science 330, 486.

  3. von Neumann Regular Rings and Right SF-rings%von Neumann正则环与右SF-环

    Institute of Scientific and Technical Information of China (English)

    周海燕; 王小冬

    2004-01-01

    A ring R is called a left (right) SF-ring if all simple left (right)R-modules are flat. It is known that von Neumann regular rings are left and right SF-rings. In this paper, we study the regularity of right SF-rings and prove that if R is a right SF-ring whose all maximal (essential) right ideals are GW-ideals, then R is regular.

  4. Saturn's Rings Reveal Unexpected Phenomena

    Institute of Scientific and Technical Information of China (English)

    李颖

    2004-01-01

    Safely in orbit around Saturn, NASA's Cassini spacecraft sent back its first close-up images of the massive planet's rings on July 1, revealing an unexpectedly varied terrain featuring surprisingly sharp edges, braids and delicate ridges.

  5. National synchrotron light source VUV storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Blumberg, L.; Bittner, J.; Galayda, J.; Heese, R.; Krinsky, S.; Schuchman, J.; van Steenbergen, A.

    1979-01-01

    A 700 MeV electron storage ring designed for synchrotron radiation applications is described. Lattice and stability calculations are presented and the vacuum, correction and injection systems are discussed.

  6. Regularities and Radicals in Near-rings

    Institute of Scientific and Technical Information of China (English)

    N.J. Groenewald

    2002-01-01

    Let F be a regularity for near-rings and F(R) the largest FR-regular ideal in R. In the first part of this paper, we introduce the concepts of maximal Fmodular ideals and F-primitive near-rings to characterize F(R) for any near-ring regularity F. Under certain conditions, F(R) is equal to the intersection of all the maximal F-modular ideals of R. As examples, we apply this to the different analogs of the Brown-McCoy radicals and also the Behrens radicals. In the last part of this paper, we show that for certain regularities, the class of F-primitive near-rings forms a special class.

  7. Exchange rings satisfying power ideal-cancellation

    Institute of Scientific and Technical Information of China (English)

    陈焕艮

    2003-01-01

    In this paper, we introduce a new kind of partial power cancellations, and get a number of necessary and sufficient conditions for exchange rings satisfying power ideal-cancellation. These also extend many known results.

  8. Comparability for ideals of regular rings

    Institute of Scientific and Technical Information of China (English)

    CHEN Huanyin

    2005-01-01

    In this paper we investigate necessary and sufficient conditions under which the ideals possess comparability structure. For regular rings, we prove that every square matrix over ideals satisfying general comparability admits a diagonal reduction by quasi invertible matrices.

  9. Medical image of the week: aortic ring

    Directory of Open Access Journals (Sweden)

    Wong C

    2014-10-01

    Full Text Available No abstract available. Article truncated after 150 words. A 78 year old man presented with altered mental status and was found to have an intraventricular hemorrhage. He was intubated for airway protection. On the post-intubation chest radiograph (Figure 1, the patient was noted to have a widening of the right paratracheal stripe. A CT chest (Figure 2 was obtained to characterize this finding and revealed an aortic ring which encircles the trachea and esophagus. Vascular rings are uncommon congenital abnormalities, accounting for approximately 1% of congenital heart disease. Complete vascular rings can occur with a right aortic arch with a ligamentum arteriosum or with a double aortic arch, such as with our patient (1. This ring can cause airway compression, stridor, esophageal compression, or no symptoms at all. As the embryo develops, the left fourth pharyngeal arch normally persists to become the aortic arch while the right fourth pharyngeal arch regresses. If both fourth pharyngeal arches persist, a ...

  10. Genetics Home Reference: ring chromosome 20 syndrome

    Science.gov (United States)

    ... 3 links) Encyclopedia: Chromosome Encyclopedia: Epilepsy Health Topic: Epilepsy Genetic and Rare Diseases Information Center (1 link) Ring chromosome 20 Additional NIH Resources (2 links) National Human Genome Research Institute: Chromosome Abnormalities National Institute of ...

  11. Genetics Home Reference: ring chromosome 14 syndrome

    Science.gov (United States)

    ... Encyclopedia: Chromosome Health Topic: Developmental Disabilities Health Topic: Epilepsy Genetic and Rare Diseases Information Center (1 link) Ring chromosome 14 Additional NIH Resources (2 links) National Human Genome Research Institute: Chromosome Abnormalities National Institute of ...

  12. Cubical Cohomology Ring of 3D Photographs

    CERN Document Server

    Gonzalez-Diaz, Rocio; Medrano, Belen; 10.1002/ima.20271

    2011-01-01

    Cohomology and cohomology ring of three-dimensional (3D) objects are topological invariants that characterize holes and their relations. Cohomology ring has been traditionally computed on simplicial complexes. Nevertheless, cubical complexes deal directly with the voxels in 3D images, no additional triangulation is necessary, facilitating efficient algorithms for the computation of topological invariants in the image context. In this paper, we present formulas to directly compute the cohomology ring of 3D cubical complexes without making use of any additional triangulation. Starting from a cubical complex $Q$ that represents a 3D binary-valued digital picture whose foreground has one connected component, we compute first the cohomological information on the boundary of the object, $\\partial Q$ by an incremental technique; then, using a face reduction algorithm, we compute it on the whole object; finally, applying the mentioned formulas, the cohomology ring is computed from such information.

  13. A Traveling Feature in Saturn's Rings

    CERN Document Server

    Rehnberg, Morgan E; Brown, Zarah L; Albers, Nicole; Sremčević, Miodrag; Stewart, Glen R

    2016-01-01

    The co-orbital satellites of Saturn, Janus and Epimetheus, swap radial positions every 4.0 years. Since \\textit{Cassini} has been in orbit about Saturn, this has occurred on 21 January in 2006, 2010, and 2014. We describe the effects of this radial migration in the Lindblad resonance locations of Janus within the rings. When the swap occurs such that Janus moves towards Saturn and Epimetheus away, nonlinear interference between now-relocated density waves launches a solitary wave that travels through the rings with a velocity approximately twice that of the local spiral density wave group velocity in the A ring and commensurate with the spiral density wave group velocity in the B ring.

  14. A non-Abelian Black Ring

    CERN Document Server

    Ortin, Tomas

    2016-01-01

    We construct a supersymmetric black ring solution of SU(2) N=1, d=5 Super-Einstein-Yang-Mills (SEYM) theory by adding a distorted BPST instanton to an Abelian black ring solution of the same theory. The change cannot be observed from spatial infinity: neither the mass, nor the angular momenta or the values of the scalars at infinity differ from those of the Abelian ring. The entropy is, however, sensitive to the presence of the non-Abelian instanton, and it is smaller than that of the Abelian ring, in analogy to what happens in the supersymmetric coloured black holes recently constructed in the same theory and in N=2, d=4 SEYM. By taking the limit in which the two angular momenta become equal we derive a non-Abelian generalization of the BMPV rotating black-hole solution.

  15. Heptaphyrins: Expanded porphyrins with seven heterocyclic rings

    Indian Academy of Sciences (India)

    Venkataramanarao G Anand; Simi K Pushpan; Sundararaman Venkatraman; Tavarekere K Chandrashekar

    2003-10-01

    Expanded porphyrins containing seven pyrrole/heterocyclic rings linked in a cyclic fashion are termed heptaphyrins. The number of -electrons in heptaphyrins depends on the number of meso carbon bridges used to link the heterocyclic rings, accordingly heptaphyrins with 28-electrons and 30 -electrons are reported to date. Both condensation reactions of the appropriate precursors and acid-catalysed oxidative coupling reactions have been utilized to synthesise the heptaphyrins. The 30 heptaphyrins exhibit rich structural diversity where some of the heterocyclic rings in the macrocycle undergo a 180° ring flipping. An overview of the synthetic methods employed for the synthesis of heptaphyrins, their spectroscopic properties, structural behaviour and aromatic properties are highlighted in this paper.

  16. SNS Ring and RTBT Beam Current Monitor

    Science.gov (United States)

    Blokland, W.; Armstrong, G.; Deibele, C.; Pogge, J.; Gaidash, V.

    2006-11-01

    The SNS Diagnostics Group has implemented Beam Current Monitors (BCM) for the Ring and RTBT (Ring to Target Beam Transferline). In the Ring, the BCM must handle a thousand-fold increase of intensity during the accumulation, and in the RTBT, the BCM must communicate the integrated charge of the beam pulse in real-time for every shot to the target division for correlation with the produced neutrons. This paper describes the development of a four channel solution for the Ring BCM and the use of FPGA for the RTBT BCM to deliver the total charge to the target over a fiber optic network. Both system versions are based on the same commercial digitizer board.

  17. Proton storage ring: man/machine interface

    International Nuclear Information System (INIS)

    The human interface of the Proton Storage Ring Control System at Los Alamos is described in some detail, together with the software environment in which operator interaction programs are written. Some examples of operator interaction programs are given

  18. A non-Abelian black ring

    Science.gov (United States)

    Ortín, Tomás; Ramírez, Pedro F.

    2016-09-01

    We construct a supersymmetric black ring solution of SU (2) N = 1, d = 5 Super-Einstein-Yang-Mills (SEYM) theory by adding a distorted BPST instanton to an Abelian black ring solution of the same theory. The change cannot be observed from spatial infinity: neither the mass, nor the angular momenta or the values of the scalars at infinity differ from those of the Abelian ring. The entropy is, however, sensitive to the presence of the non-Abelian instanton, and it is smaller than that of the Abelian ring, in analogy to what happens in the supersymmetric colored black holes recently constructed in the same theory and in N = 2, d = 4 SEYM. By taking the limit in which the two angular momenta become equal we derive a non-Abelian generalization of the BMPV rotating black-hole solution.

  19. Ion clearing the the XLS-ring

    Energy Technology Data Exchange (ETDEWEB)

    Bozoki, E.S.; Halama, H.

    1990-01-01

    The mechanism of ion capture by the beam, their effects on the beam as well as ways to clear the ions are discussed. Special attention is given to these questions for the SXLS ring. 20 refs., 5 figs., 4 tabs.

  20. Ion clearing the the XLS-ring

    International Nuclear Information System (INIS)

    The mechanism of ion capture by the beam, their effects on the beam as well as ways to clear the ions are discussed. Special attention is given to these questions for the SXLS ring. 20 refs., 5 figs., 4 tabs

  1. Polarized light bursts from kicked quantum rings

    OpenAIRE

    Moskalenko, A.S.; Berakdar, J.

    2008-01-01

    Non-equilibrium quantum rings emit circular polarized subterahertz radiation with a polarization degree controllable on nano- to picosecond time scales. This we conclude using a theory developed here for the time-dependent detection of the circular polarization of polychromatic radiations, valid for time scales comparable to the reciprocal of characteristic emission frequencies. The theory is applied to driven quantum rings whereby the influence of radiative and non-radiative processes on the...

  2. Hitchhikers’ guide to analysing bird ringing data

    OpenAIRE

    Harnos Andrea; Fehérvári Péter; Csörgő Tibor

    2015-01-01

    Bird ringing datasets constitute possibly the largest source of temporal and spatial information on vertebrate taxa available on the globe. Initially, the method was invented to understand avian migration patterns. However, data deriving from bird ringing has been used in an array of other disciplines including population monitoring, changes in demography, conservation management and to study the effects of climate change to name a few. Despite the widespread usage and importance, there are n...

  3. Integral Ring Carbon-Carbon Piston

    Science.gov (United States)

    Northam, G. Burton (Inventor)

    1999-01-01

    An improved structure for a reciprocating internal combustion engine or compressor piston fabricate from carbon-carbon composite materials is disclosed. An integral ring carbon-carbon composite piston, disclosed herein, reduces the need for piston rings and for small clearances by providing a small flexible, integral component around the piston that allows for variation in clearance due to manufacturing tolerances, distortion due to pressure and thermal loads, and variations in thermal expansion differences between the piston and cylinder liner.

  4. NOETHERIAN GR-REGULAR RINGS ARE REGULAR

    Institute of Scientific and Technical Information of China (English)

    LIHUISHI

    1994-01-01

    It is proved that for a left Noetherian z-graded ring A,if every finitely generated graded A-module has finite projective dimension(i.e-,A is gr-regular)then every finitely generated A-module has finite projective dimension(i.e.,A is regular).Some applications of this result to filtered rings and some classical cases are also given.

  5. Inelastic scattering of neutrons by superconducting rings

    OpenAIRE

    Agafonov, A. I.

    2010-01-01

    The differential cross section for the inelastic magnetic scattering of neutrons by superconducting rings is derived theoretically taking account of the interaction of the neutron magnetic moment with magnetic field created by the superconducting current. In this scattering process the neutron kinetic energy increases discretely and, respectively, the number of the magnetic flux quanta trapped in the ring, reduces. Quantitative calculations of the scattering cross section for cold neutrons is...

  6. Tube Dynamics Works for Randomly Entangled Rings.

    Science.gov (United States)

    Qin, Jian; Milner, Scott T

    2016-02-12

    The tube model is the cornerstone of molecular theory for polymer rheology. We test its microscopic assumptions by simulating topologically equilibrated ring polymers, whose dynamics is free from end segment relaxation. We show that a closed-form expression derived from the tube model adapted to ring polymers quantitatively predicts the segmental mean squared displacements over the entire range of time scales from local motion to complete equilibration, with a time-independent local friction factor.

  7. Bosonic and Fermionic Dipoles on a Ring

    DEFF Research Database (Denmark)

    Zöllner, Sascha; Bruun, Georg; Pethick, Christopher;

    2011-01-01

    We show that dipolar bosons and fermions confined in a quasi-one-dimensional ring trap exhibit a rich variety of states because their interaction is inhomogeneous. For purely repulsive interactions, with increasing strength of the dipolar coupling there is a crossover from a gaslike state to an i...... to an inhomogeneous crystal-like one. For small enough angles between the dipoles and the plane of the ring, there are regions with attractive interactions, and clustered states can form....

  8. Multiperfect Numbers in Certain Quadratic Rings

    OpenAIRE

    Defant, Colin

    2015-01-01

    Using an extension of the abundancy index to imaginary quadratic rings that are unique factorization domains, we investigate what we call $n$-powerfully $t$-perfect numbers in these rings. This definition serves to extend the concept of multiperfect numbers that have been defined and studied in the integers. At the end of the paper, as well as at various points throughout the paper, we point to some potential areas for further research.

  9. Fluxoid dynamics in superconducting thin film rings

    OpenAIRE

    Kirtley, J. R.; Tsuei, C. C.; Kogan, V. G.; Clem, J. R.; Raffy, H.; Li, Z. Z.

    2003-01-01

    We have measured the dynamics of individual magnetic fluxoids entering and leaving photolithographically patterned thin film rings of the underdoped high-temperature superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+\\delta}$, using a variable sample temperature scanning SQUID microscope. These results can be qualitatively described using a model in which the fluxoid number changes by thermally activated nucleation of a Pearl vortex in, and transport of the Pearl vortex across, the ring wall.

  10. A transformable tensegrity-ring footbridge

    OpenAIRE

    Rhode-Barbarigos, Landolf; Motro, René; Smith, Ian F.C.

    2012-01-01

    International audience Tensegrity structures are spatial reticulated structures composed of cables and struts. A tension-compression equilibrium leads to lightweight systems that change shape through length changes in their members. Active members thus control several degrees of freedom simultaneously. Tensegrity-ring modules are transformable circuit-pattern modules. The linear combination of tensegrity rings has been shown to be viable for a footbridge application. Shape transformations ...

  11. Recent studies on the PRISM FFAG ring

    International Nuclear Information System (INIS)

    Next generation lepton flavour violation experiments require high intensity and high quality muon beams. The PRISM Task Force focuses on accelerator R and D for realizing such beams using an FFAG ring. The scaling and non-scaling designs for the PRISM FFAG ring are discussed. The recent studies on injection/extraction systems and matching to the solenoid channel are outlined. The future plans for the study are presented.

  12. Beam halo study on ATF damping ring

    CERN Document Server

    Wang, Dou; Yokoya, Kaoru; Naito, Takashi; Gao, Jie

    2016-01-01

    Halo distribution is a key topic for background study. This paper has developed an analytical method to give an estimation of ATF beam halo distribution. The equilibrium particle distribution of the beam tail in the ATF damping ring is calculated analytically with different emittance and different vacuum degree. The analytical results agree the measurements very well. This is a general method which can be applied to any electron rings.

  13. Prometheus Induced Vorticity in Saturn's F Ring

    Science.gov (United States)

    Sutton, Phil J.; Kusmartsev, Feo V.

    2016-09-01

    Saturn's rings are known to show remarkable real time variability in their structure. Many of which can be associated to interactions with nearby moons and moonlets. Possibly the most interesting and dynamic place in the rings, probably in the whole Solar System, is the F ring. A highly disrupted ring with large asymmetries both radially and azimuthally. Numerically non-zero components to the curl of the velocity vector field (vorticity) in the perturbed area of the F ring post encounter are witnessed, significantly above the background vorticity. Within the perturbed area rich distributions of local rotations is seen located in and around the channel edges. The gravitational scattering of ring particles during the encounter causes a significant elevated curl of the vector field above the background F ring vorticity for the first 1-3 orbital periods post encounter. After 3 orbital periods vorticity reverts quite quickly to near background levels. This new found dynamical vortex life of the ring will be of great interest to planet and planetesimals in proto-planetary disks where vortices and turbulence are suspected of having a significant role in their formation and migrations. Additionally, it is found that the immediate channel edges created by the close passage of Prometheus actually show high radial dispersions in the order ~20-50 cm/s, up to a maximum of 1 m/s. This is much greater than the value required by Toomre for a disk to be unstable to the growth of axisymmetric oscillations. However, an area a few hundred km away from the edge shows a more promising location for the growth of coherent objects.

  14. Quantum pumping : coherent rings versus open conductors

    OpenAIRE

    Moskalets, Mykhaylo; Buttiker, Markus

    2003-01-01

    We examine adiabatic quantum pumping generated by an oscillating scatterer embedded in a one-dimensional ballistic ring and compare it with pumping caused by the same scatterer connected to external reservoirs. The pumped current for an open conductor, paradoxically, is non-zero even in the limit of vanishing transmission. In contrast, for the ring geometry the pumped current vanishes in the limit of vanishing transmission. We explain this paradoxical result and demonstrate that the physics u...

  15. SNS RING STUDY AT THE AGS BOOSTER.

    Energy Technology Data Exchange (ETDEWEB)

    ZHANG, S.Y.; AHRENS, L.; BEEBE-WANG, J.; BLASKIEWICZ, M.; FEDOTOV, A.; GARDNER, C.; LEE, Y.Y.; LUCCIO, A.; MALITSKY, N.; ROSER, T.; WENG, W.T.; WEI, J.; ZENO, K.; REECE, K.; WANG, J.G.

    2000-06-30

    During the g-2 run at the BNL AGS in early 2000, a 200 MeV storage-ring-like magnetic cycle has been set-up and tuned at the Booster in preparing for the Spallation Neutron Source (SNS) accumulator ring study. In this article, we report the progress of the machine set-up, tuning, some preliminary studies, and the future plan.

  16. Intensity Scintillations in Planetary Ring Occultations: Simulations

    Science.gov (United States)

    Marouf, E.

    2003-12-01

    A combined analytical and numerical simulation approach is used to investigate the first, second, and fourth statistical averages of the signal observed during a ring occultation experiment. The rings are modeled as a randomly blocked diffraction screen. The field behind the screen (the rings) assumes binary values: zero if located in the shadow area cast by ring particles and the full incident field otherwise. The stochastic geometry of the union of shadow areas cast behind the rings defines a so-called Boolean model. Either the random wavefront formed behind the screen or it's statistical averages can be propagated to an observer (a detector) some distance away from the diffraction screen. The parabolic approximation of the wave equation is used to model near-forward diffraction effects over the free-space path from the ring plane to the observation plane. The first and second moments were previously shown to correspond to the well-known coherent and scattered signal components observed during radio occultation experiments. Of particular interest here is the fourth moment of the random field at the observer, which determines the intensity scintillation index. Numerical simulations are used to investigate its behavior as a function of relevant model parameters, in particular, the ring particle radius and the Fresnel scale of observation. A monodispersion of ring particles is assumed to keep the model as simple as possible so as to investigate conditions under which the particle size may be recoverable from the intensity scintillation measurements. The model is also idealized to one-dimensional diffraction screen in order to speed up the computations; however, simulations of the more realistic two-dimensional diffraction screen models are also carried out.

  17. Installation of reactor vessel support ring

    International Nuclear Information System (INIS)

    Installation activities of reactor vessel support ring for Unit 1 and Unit 2 of Daya Bay Nuclear Power Plant were presented, including prerequisites, handling, assembling, positioning, second-stage concreting, inspection and documentation. In particular, the processing of non-conformances for Unit 1 as experience feedback leading to the design modification which has been applied in the support ring assembling activities for Unit 2 was introduced. (9 figs, 1 tab.)

  18. Hjernen og læring

    DEFF Research Database (Denmark)

    Lauridsen, Ole

    Hjernen og læring bygger på de seneste 15-20 års forskningsresultater i spændingsfeltet mellem neurovidenskab, psykologi og pædagogik. På baggrund af denne viden om, hvordan hjernen arbejder, får læseren praktiske redskaber til at tilrettelægge undervisning og egen læring så effektivt som muligt....

  19. Generalized Inverses of Matrices over Rings

    Institute of Scientific and Technical Information of China (English)

    韩瑞珠; 陈建龙

    1992-01-01

    Let R be a ring,*be an involutory function of the set of all finite matrices over R. In this pa-per,necessary and sufficient conditions are given for a matrix to have a (1,3)-inverse,(1,4)-inverse,or Morre-Penrose inverse,relative to *.Some results about generalized inverses of matrices over division rings are generalized and improved.

  20. Gravitating Stationary Dyons and Rotating Vortex Rings

    CERN Document Server

    Kleihaus, B; Neemann, U; Kleihaus, Burkhard; Kunz, Jutta; Neemann, Ulrike

    2005-01-01

    We construct dyons, and electrically charged monopole-antimonopole pairs and vortex rings in Yang-Mills-Higgs theory coupled to Einstein gravity. The solutions are stationary, axially symmetric and asymptotically flat. The dyons with magnetic charge $n\\ge 2$ represent non-static solutions with vanishing angular momentum. The electrically charged monopole-antimonopole pairs and vortex rings, in contrast, possess vanishing magnetic charge, but finite angular momentum, equaling $n$ times their electric charge.

  1. Magnetic Reversal in Nanoscopic Ferromagnetic Rings

    OpenAIRE

    Martens, Kirsten; Stein, D. L.; Kent, A. D.

    2004-01-01

    We present a theory of magnetization reversal due to thermal fluctuations in thin submicron-scale rings composed of soft magnetic materials. The magnetization in such geometries is more stable against reversal than that in thin needles and other geometries, where sharp ends or edges can initiate nucleation of a reversed state. The 2D ring geometry also allows us to evaluate the effects of nonlocal magnetostatic forces. We find a `phase transition', which should be experimentally observable, b...

  2. N-topo nilpotency in fuzzy neighborhood rings

    Directory of Open Access Journals (Sweden)

    Fawzi Al-Thukair

    2004-03-01

    Full Text Available We introduce the notion of N-topo nilpotent fuzzy set in a fuzzy neighborhood ring and develop some fundamental results. Here we show that a fuzzy neighborhood ring is locally inversely bounded if and only if for all 0<α<1, the α-level topological rings are locally inversely bounded. This leads us to prove a characterization theorem which says that if a fuzzy neighborhood ring on a division ring is Wuyts-Lowen WNT2 and locally inversely bounded, then the fuzzy neighborhood ring is a fuzzy neighborhood division ring. We also present another characterization theorem which says that a fuzzy neighborhood ring on a division ring is a fuzzy neighborhood division ring if the fuzzy neighborhood ring contains an N-topo nilpotent fuzzy neighborhood of zero.

  3. Localized Perturbations in Saturn's C Ring

    Science.gov (United States)

    Spitale, Joseph N.; Tiscareno, Matthew S.

    2016-10-01

    Years of high-resolution imaging of Saturn's rings have revealed many examples of perturbations arising from local causes. For example, the presence of 100-m-scale and smaller moonlets is inferred in the A ring based on the propeller-shaped disturbances that they create (Tiscareno et al. 2006, 2010); the F ring is shaped by regular collisions with its shepherd Prometheus, as well as with other smaller bodies orbiting in the vicinity (Murray et al. 2005, 2008); the "wisps" on the outer edge of the Keeler gap (Porco et al. 2005) may mark the locations of small moonlets that have emerged from the A ring (Tiscareno and Arnault 2015); wakes in the Huygens ringlet imply the presence of two multi-km bodies, and the irregular shape of its inner edge suggests the presence of many smaller bodies (Spitale and Hahn 2016); based on shadow measurements, the B ring contains an embedded 300-m object that produces a small propeller-shaped disturbance (Spitale and Porco 2010; Spitale and Tiscareno 2012).Here, we present evidence for localized perturbations in the C ring. The ringlet embedded in the Bond gap, near 1.470 Saturn radii, shows discrete clumps orbiting at the Keplerian rate in images spanning about eight years. The clumps are not detected in all image sequences at the expected longitudes. The Dawes ringlet, near 1.495 Saturn radii, has an irregular edge that does not appear as a simple superposition of low-wavenumber normal modes.

  4. Collisional Features in Saturn's F Ring

    Science.gov (United States)

    Attree, Nicholas Oliver; Murray, Carl; Cooper, Nicholas; Williams, Gareth

    2016-10-01

    Saturn's highly dynamic F ring contains a population of small (radius ~ 1 km) moonlets embedded within its core or on nearby orbits. These objects interact, both gravitationally and collisionally, with the ring producing a range of features, some of which are unique to it. Here we present a brief overview of F ring collisional processes, investigated using a combination of Cassini imaging, simulations and orbital dynamics. Collisions produce linear debris clouds, known as 'jets' and 'mini-jets', which evolve, due to differential orbital motion, over periods ranging from hours to months. Mini-jet-forming collisions occur daily in the F ring whilst larger, more dramatic, events are rarer but produce jets that persist for many months, 'wrapping around' the ring to form almost parallel strands. Measuring jet properties, such as formation rates and relative orbits, allows us to infer a local population of order hundreds of objects colliding at relative velocities of a few metres per second. N-body modelling of the collisions shows good agreement with observations when two aggregates are allowed to impact and partially fragment (as opposed to a solid moonlet encountering dust), implying massive objects both in the core and nearby. Multiple, repeated collisions by the same, or fragments of the same, object are also important in explaining some jet morphology, showing that many objects survive the collisions. The F ring represents a natural laboratory for observing low-velocity collisions between icy objects as well as the ongoing aggregation and accretion that most-likely forms them.

  5. Hitchhikers’ guide to analysing bird ringing data

    Directory of Open Access Journals (Sweden)

    Harnos Andrea

    2015-12-01

    Full Text Available Bird ringing datasets constitute possibly the largest source of temporal and spatial information on vertebrate taxa available on the globe. Initially, the method was invented to understand avian migration patterns. However, data deriving from bird ringing has been used in an array of other disciplines including population monitoring, changes in demography, conservation management and to study the effects of climate change to name a few. Despite the widespread usage and importance, there are no guidelines available specifically describing the practice of data management, preparation and analyses of ringing datasets. Here, we present the first of a series of comprehensive tutorials that may help fill this gap. We describe in detail and through a real-life example the intricacies of data cleaning and how to create a data table ready for analyses from raw ringing data in the R software environment. Moreover, we created and present here the R package; ringR, designed to carry out various specific tasks and plots related to bird ringing data. Most methods described here can also be applied to a wide range of capture-recapture type data based on individual marking, regardless to taxa or research question.

  6. Near-Ring Radicals and Class Pairs

    Institute of Scientific and Technical Information of China (English)

    L.Godloza; N.J.Groenewald; W.A.Olivier

    2005-01-01

    For near-ring ideal mappings p1 and p2, we investigate radical theoretical properties of and the relationship among the class pairs (p1: p2), (Sp2: Sp1) and (Rp2:Rp1). Conditions on p1 and p2 are given for a general class pair to form a radical class of various types. These types include the Plotkin and KA-radical varieties. A number of examples are shown to motivate the suitability of the theory of Hoehnke-radicals over KA-radicals when radical pairs of near-rings are studied. In particular, it is shown that (pc: P3) forms a KA-radical class, where Pc denotes the class of completely prime nearrings and P3 the class of 3-prime near-rings. This gives another near-ring generalization of the 2-primal ring concept. The theory of radical pairs are also used to show that in general the class of 3-semiprime near-rings is not the semisimple class of the 3-prime radical.

  7. Polar ring galaxies as tests of gravity

    CERN Document Server

    Lüghausen, F; Kroupa, P; Angus, G; Combes, F; Gentile, G; Tiret, O; Zhao, H

    2013-01-01

    Polar ring galaxies are ideal objects with which to study the three-dimensional shapes of galactic gravitational potentials since two rotation curves can be measured in two perpendicular planes. Observational studies have uncovered systematically larger rotation velocities in the extended polar rings than in the associated host galaxies. In the dark matter context, this can only be explained through dark halos that are systematically flattened along the polar rings. Here, we point out that these objects can also be used as very effective tests of gravity theories, such as those based on Milgromian dynamics (MOND). We run a set of polar ring models using both Milgromian and Newtonian dynamics to predict the expected shapes of the rotation curves in both planes, varying the total mass of the system, the mass of the ring with respect to the host, as well as the size of the hole at the center of the ring. We find that Milgromian dynamics not only naturally leads to rotation velocities being typically higher in th...

  8. Phase behaviour of polyethylene knotted ring chains

    Institute of Scientific and Technical Information of China (English)

    Wen Xiao-Hui; Zhang Lin-Xi; Xia A-Gen; Chen Hong-Ping

    2011-01-01

    The phase behaviour of polyethylene knotted ring chains is investigated by using molecular dynamics simulations.In this paper, we focus on the collapse of the polyethylene knotted ring chain, and also present the results of linear and ring chains for comparison. At high temperatures, a fully extensive knot structure is observed. The mean-square radius of gyration per bond〈S2〉/(Nb2)and the shape factor(δ*)depend on not only the chain length but also the knot type.With temperature decreasing, chain collapse is observed, and the collapse temperature decreases with the chain length increasing. The actual collapse transition can be determined by the specific heat capacity Cv, and the knotted ring chain undergoes gas-liquid-solid-like transition directly. The phase transition of a knotted ring chain is only one-stage collapse, which is different from the polyethylene linear and ring chains. This investigation can provide some insights into the statistical properties of knotted polymer chains.

  9. Circuit description of unipolar DC-to-DC converters for APS storage ring quadrupoles and sextupoles

    International Nuclear Information System (INIS)

    This paper describes the control, interlock, and power circuits for 680 unipolar switch mode DC-to-DC converters used to regulate the Advanced Photon Sources (APS's) storage ring quadrupole and sextupole magnet currents. Quadrupole current stability is ± 6x10-5 and the sextupole current stability is ±3x10-4. The stability is obtained with pulse width modulation, operating at a switching frequency of 20kHz with full current switching. The converters are housed in 200 cabinets located on top of the storage ring tunnel. Raw DC power is distributed from 80 AC-to-DC power supplies, four at each of 20 locations around the storage ring. Voltages, currents, and temperatures are computer monitored and logged for the converters and magnets. All converters and magnets are water cooled with the flow and pressure monitored at the inlet and outlet of groups. Water is interlocked with the raw power supplies and not the individual converters

  10. ADVANCE PAYMENTS

    CERN Multimedia

    Human Resources Division

    2002-01-01

    Administrative Circular Nº 8 makes provision for the granting of advance payments, repayable in several monthly instalments, by the Organization to the members of its personnel. Members of the personnel are reminded that these advances are only authorized in exceptional circumstances and at the discretion of the Director-General. In view of the current financial situation of the Organization, and in particular the loans it will have to incur, the Directorate has decided to restrict the granting of such advances to exceptional or unforeseen circumstances entailing heavy expenditure and more specifically those pertaining to social issues. Human Resources Division Tel. 73962

  11. Advance payments

    CERN Multimedia

    Human Resources Division

    2003-01-01

    Administrative Circular N 8 makes provision for the granting of advance payments, repayable in several monthly instalments, by the Organization to the members of its personnel. Members of the personnel are reminded that these advances are only authorized in exceptional circumstances and at the discretion of the Director-General. In view of the current financial situation of the Organization, and in particular the loans it will have to incur, the Directorate has decided to restrict the granting of such advances to exceptional or unforeseen circumstances entailing heavy expenditure and more specifically those pertaining to social issues. Human Resources Division Tel. 73962

  12. Unit Regular Rings and SF-rings%单位正则环和SF-环

    Institute of Scientific and Technical Information of China (English)

    葛平红; 储茂权

    2009-01-01

    环 R 称为左SF-环,如果每个单左 R- 模是平坦的.众所周知,单位正则环是SF-环,但SF-环是否为单位正则却未有结果.本文主要研究左SF-环成为单位正则环的条件及在一定条件下SF-环与单位正则环的等价性.%A ring R is defined to be a left SF-ring if all simple left R-modules are flat. It is well known that unit regular rings are SF-rings. But the question whether a left SF-ring is necessarily unit regular remains unanswered. In this paper, we mainly study some conditions that left SF-rings turn into unit regular rings and the equivalence that left SF-rings and unit regular rings are encircled under certain conditions.

  13. [Laser Induced Fluorescence Spectroscopic Analysis of Aromatics from One Ring to Four Rings].

    Science.gov (United States)

    Zhang, Peng; Liu, Hai-feng; Yue, Zong-yu; Chen, Bei-ling; Yao, Ming-fa

    2015-06-01

    In order to distinguish small aromatics preferably, a Nd : YAG Laser was used to supply an excitation laser, which was adjusted to 0.085 J x cm(-2) at 266 nm. Benzene, toluene, naphthalene, phenanthrene, anthracene, pyrene and chrysene were used as the representative of different rings aromatics. The fluorescence emission spectra were researched for each aromatic hydrocarbon and mixtures by Laser induced fluorescence (LIF). Results showed that the rings number determined the fluorescence emission spectra, and the structure with same rings number did not affect the emission fluorescence spectrum ranges. This was due to the fact that the absorption efficiency difference at 266 nm resulted in that the fluorescence intensities of each aromatic hydrocarbon with same rings number were different and the fluorescence intensities difference were more apparently with aromatic ring number increasing. When the absorption efficiency was similar at 266 nm and the concentrations of each aromatic hydrocarbon were same, the fluorescence intensities were increased with aromatic ring number increasing. With aromatic ring number increasing, the fluorescence spectrum and emission peak wavelength were all red-shifted from ultraviolet to visible and the fluorescence spectrum range was also wider as the absorption efficiency was similar. The fluorescence emission spectra from one to four rings could be discriminated in the following wavelengths, 275 to 320 nm, 320 to 375 nm, 375 to 425 nm, 425 to 556 nm, respectively. It can be used for distinguish the type of the polycyclic aromatic hydrocarbons (PAHs) as it exists in single type. As PAHs are usually exist in a variety of different rings number at the same time, the results for each aromatic hydrocarbon may not apply to the aromatic hydrocarbon mixtures. For the aromatic hydrocarbon mixtures, results showed that the one- or two-ring PAHs in mixtures could not be detected by fluorescence as three- or four-ring PAHs existed in mixture

  14. Improved Data Search Capability At The PDS Rings Node

    Science.gov (United States)

    Gordon, Mitchell K.; Ballard, L.; Showalter, M. R.; Heather, N.

    2007-10-01

    As the number and complexity of NASA's data sets grow, users legitimately face the "needle-in-a-haystack" problem of zeroing in on the finite set of data products most relevant to a particular scientific question. They expect to be able to query the archive using a rich set of reliable metadata, without necessarily knowing in advance which data set(s) might hold the answers, or even whether an answer can be found within the archive's holdings. The Rings Node is developing a web-based search engine that is capable of meeting many of these challenges. The user can start a query at a very high level (e.g., images of Saturn) and "drill down" through all the available holdings to reach the desired data products (e.g., infrared images of Saturn's F ring at low phase angle and resolution finer than 5 km per pixel). The interface responds quickly to each new constraint entered by the user, removing irrelevant options and adding new ones as appropriate. For example, if it is determined that only Cassini images fit the constraints entered so far, then a page of Cassini-related constraints becomes available but options for occultation profiles and Hubble data are hidden. At each step, the engine displays a live tally of how many available products match the user's constraints. Using Ajax technology, caching of previous results, and a highly optimized database, the system is quick and responsive in spite of the millions of database records that must be searched. The proto-type was unveiled for the COSPAR Capacity Building Workshop on Planetary Science, held in Montevideo, Uruguay earlier this year. The new search engine can be accessed at http://pds-rings.seti.org/catalog/.

  15. Advanced light source master oscillator

    International Nuclear Information System (INIS)

    The Master Oscillator of the Advanced Light Source operates at a frequency of 499.654 MHz which is the 328th harmonic of the storage ring. The oscillator is capable of providing up to a maximum of ± 500 KHz frequency deviation for various experimental purposes. Provisions for external signal injection as well as using an external signal source have been designed into the unit. A power distribution system has also been included to provide signals for various parts of the ALS machine and user requirements. The Master Oscillator is made up with modules housed in a Euro chassis. 4 refs., 7 figs

  16. Advanced nanoelectronics

    CERN Document Server

    Ismail, Razali

    2012-01-01

    While theories based on classical physics have been very successful in helping experimentalists design microelectronic devices, new approaches based on quantum mechanics are required to accurately model nanoscale transistors and to predict their characteristics even before they are fabricated. Advanced Nanoelectronics provides research information on advanced nanoelectronics concepts, with a focus on modeling and simulation. Featuring contributions by researchers actively engaged in nanoelectronics research, it develops and applies analytical formulations to investigate nanoscale devices. The

  17. The vasorelaxing effect of hydrogen sulfide on isolated rat aortic rings versus pulmonary artery rings

    Institute of Scientific and Technical Information of China (English)

    Yan SUN; Chao-shu TANG; Hong-fang JIN; Jun-bao DU

    2011-01-01

    Aim:To compare the vasorelaxing effects of hydrogen sulfide(H2S)on isolated aortic and pulmonary artery rings and to determine their action mechanisms.Methods:H2S-induced vasorelaxation of isolated rat aortic versus pulmonary artery tings under 95%02 and 5%CO2 was analyzed.The expression of cystathinonine gamma-lyase(CSE),cystathionine beta synthase(CBS),3-memaptopyruvate sulfurtransferase(3MST),SUR2B and Kir6.1 was examined.Results:NaHS caused vasorelaxation of rat aortic and pulmonary artery rings in a dose-dependent mannener NaHS dilated aortic rings to a greater extent(16.4%,38.4%,64.1%,84.3%,and 95.9%at concentrations of 50,100.200, 500,and 1000 μmol/L,respectively)than pulmonary artery rings(10.1%,22.2%.50.6%,73.6%,and 84.6%at concentrations of 50,100,200, 500 and 1000 μmol/L,respectively).The EC50 of the vasorelaxant effect for aortic rings was 152.17 pmol/L,whereas the EC50 for pulmonary artery tings was233.65 μmol/L.The vasorelaxing effect of H2was markedly blocked b y cellular and mitochondrial membrane Km channel blockers in aortic rings(P<0.01).In contrast.only the cellular membrane KATP channel blocker inhibited H2S-induced vasorelaxation in pulmonary artery rings.SUR2B mRNA and protein expression was higher in aortic rings than in pulmonary artery rings.Cystathinonine gamma-lyase(CSE)but not cystathionine beta synthase(CBS)expression in aortic rings was higher than in pulmonary artery rings.3.Mercapto PYruvate sulfurtransferase(3MST)mRNA was lower in aortic rings than in pulmonary artery rings.Conclusion:The vasorelaxing effect of H2S on isolated aortic rings was more pronounced than the effect on pulmonary artery rings at specific concentrations,which might be associated with increased expression of the KATP channel subunit SUR2B.

  18. Proceedings of the workshop on polarized targets in storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Holt, R.J. (ed.)

    1984-08-01

    Polarization phenomena have played an increasingly important part in the study of nuclei and nucleons in recent years. Polarization studies have been hampered by the relatively few and rather fragile polarized targets which are presently available. The concept of polarized gas targets in storage rings opens a much wider range of possibilities than is available in the external target geometry. This novel method will represent a considerable advance in nuclear physics and will continue to receive much attention in plans for future facilities. An internal, polarized-target station is being planned for the cooler ring at the Indiana University Cyclotron Facility. Internal targets are compatible with recent designs of electron accelerators proposed by the Massachusetts Institute of Technology and the Southeastern Universities Research Association. The key to nuclear-science programs based on internal targets pivots on recent developments in polarized atomic beam methods, which include the more recent laser-driven polarized targets. The workshop drew together a unique group of physicists in the fields of high-energy, nuclear and atomic physics. The meeting was organized in a manner that stimulated discussion among the 58 participants and focused on developments in polarized target technology and the underlying atomic physics. An impressive array of future possibilities for polarized targets as well as current developments in polarized target technology were discussed at the workshop. Abstracts of individual items from the workshop were prepared separately for the data base.

  19. Proceedings of the workshop on polarized targets in storage rings

    International Nuclear Information System (INIS)

    Polarization phenomena have played an increasingly important part in the study of nuclei and nucleons in recent years. Polarization studies have been hampered by the relatively few and rather fragile polarized targets which are presently available. The concept of polarized gas targets in storage rings opens a much wider range of possibilities than is available in the external target geometry. This novel method will represent a considerable advance in nuclear physics and will continue to receive much attention in plans for future facilities. An internal, polarized-target station is being planned for the cooler ring at the Indiana University Cyclotron Facility. Internal targets are compatible with recent designs of electron accelerators proposed by the Massachusetts Institute of Technology and the Southeastern Universities Research Association. The key to nuclear-science programs based on internal targets pivots on recent developments in polarized atomic beam methods, which include the more recent laser-driven polarized targets. The workshop drew together a unique group of physicists in the fields of high-energy, nuclear and atomic physics. The meeting was organized in a manner that stimulated discussion among the 58 participants and focused on developments in polarized target technology and the underlying atomic physics. An impressive array of future possibilities for polarized targets as well as current developments in polarized target technology were discussed at the workshop. Abstracts of individual items from the workshop were prepared separately for the data base

  20. Pulse Power Modulator development for the CLIC Damping Ring Kickers

    CERN Document Server

    Holma, Janne

    2012-01-01

    The Compact Linear Collider (CLIC) study is exploring the scheme for an electron-positron collider with high luminosity (10-34 – 10-35 cm-2s-1) and a nominal centre-of-mass energy of 3 TeV: CLIC would complement LHC physics in the multi-TeV range. The CLIC design relies on Pre-Damping Rings (PDR) and Damping Rings (DR) to achieve the very low emittance, through synchrotron radiation, needed for the luminosity requirements of CLIC. To limit the beam emittance blow-up due to oscillations, the pulse power modulators for the DR kickers must provide extremely flat, high-voltage pulses: the 2 GHz specification called for a 160 ns duration flat-top of 12.5 kV, 250 A, with a combined ripple and droop of not more than ±0.02 %. In order to meet these demanding specifications, a combination of broadband impedance matching, optimized electrical circuit layout and advanced control techniques is required. A solid-state modulator, the inductive adder, is the most promising approach to meeting the demanding specifications...

  1. VLA Discovers Giant Rings Around Galaxy Cluster

    Science.gov (United States)

    2006-11-01

    Astronomers using the National Science Foundation's Very Large Array (VLA) radio telescope have discovered giant, ring-like structures around a cluster of galaxies. The discovery provides tantalizing new information about how such galaxy clusters are assembled, about magnetic fields in the vast spaces between galaxy clusters, and possibly about the origin of cosmic rays. Radio-Optical Image of Cluster Galaxy Cluster Abell 3376 (Radio/Optical) CREDIT: Joydeep Bagchi, IUCAA, NRAO/AUI/NSF Above, a combined radio/optical image shows the galaxy cluster Abell 3376 in visible light (blue) and radio (red) images. The giant radio arcs surrounding the cluster were discovered using the Very Large Array. The visible-light image is from the Digitized Sky survey. Below, an X-ray image of Abell 3376 made using the European Space Agency's XMM-Newton telescope shows a spectacular, bullet-shaped region of X-rays coming from gas heated to 60 million degrees Kelvin. The bullet shape results from the supersonic collision of a smaller smaller galaxy subcluster with the main body of the larger cluster. Click on images for larger version. X-Ray Image of Cluster Galaxy Cluster Abell 3376 (X-Ray) CREDIT: Joydeep Bagchi, IUCAA, ESA "These giant, radio-emitting rings probably are the result of shock waves caused by violent collisions of smaller groups of galaxies within the cluster," said Joydeep Bagchi, of the Inter-University Centre for Astronomy and Astrophysics in Pune, India, who led an international research team. The scientists reported their findings in the November 3 edition of the journal Science. The newly-discovered ring segments, some 6 million light-years across, surround a galaxy cluster called Abell 3376, more than 600 million light-years from Earth. They were revealed because fast-moving electrons emitted radio waves as they spiraled around magnetic field lines in intergalactic space. "Even from this large distance, the feeble radio waves were easily picked up by the VLA

  2. Simulation of damage evolution during hot ring rolling

    NARCIS (Netherlands)

    Wang, Chao

    2016-01-01

    Ring rolling provides a cost-effective process route for manufacturing seamless rings. The bearing rings, i.e. the inner race and the outer race of a rolling bearing, are typically manufactured by the hot ring rolling process. Bearing steels have a relatively high alloy content for improved hardenab

  3. 46 CFR 180.70 - Ring life buoys.

    Science.gov (United States)

    2010-10-01

    ... the ring life buoy. (3) Each floating waterlight installed after March 11, 1997, on a vessel carrying... 46 Shipping 7 2010-10-01 2010-10-01 false Ring life buoys. 180.70 Section 180.70 Shipping COAST...) LIFESAVING EQUIPMENT AND ARRANGEMENTS Ring Life Buoys and Life Jackets § 180.70 Ring life buoys. (a) A...

  4. Ring current development during high speed streams

    Science.gov (United States)

    Jordanova, V. K.; Matsui, H.; Puhl-Quinn, P. A.; Thomsen, M. F.; Mursula, K.; Holappa, L.

    2009-07-01

    Episodes of southward (Bzdynamics with a CME-driven storm of similar strength during 22-23 April 2001. We use our kinetic ring current-atmosphere interactions model (RAM), and investigate the mechanisms responsible for trapping particles and for causing their loss. Ring current evolution depends on the interplay of time-dependent inflow of plasma from the magnetotail, particle acceleration and loss (mainly due to charge exchange) along adiabatic drift paths, and outflow of plasma from the dayside magnetopause; all of these processes are incorporated in our model. We compare results from simulations using a newly developed, Cluster data based, University of New Hampshire inner magnetospheric electric field (UNH-IMEF) convection model with simulations using a Volland-Stern (V-S) type convection model. We find that, first, periods of increased magnetospheric convection coinciding with enhancements of plasma sheet density are needed for strong ring current buildup. Second, during the HSS-driven storm the convection potential from UNH-IMEF model is highly variable and causes sporadic shallow injections resulting in a weak ring current. The long period of enhanced convection during the CME-driven storm causes a continuous ion injection penetrating to lower L shells and stronger ring current buildup. V-S model predicts larger ring current injection during both storms. Third, the RAM driven by either convection model underestimates the total ring current energy during the recovery phase of the HSS storm, thus indicating that additional injections from substorm-induced electric fields and/or radial diffusion are needed to better reproduce its several-day long geomagnetic activity.

  5. Ring Orbits from Multiple Occultation Observations

    Science.gov (United States)

    French, Richard G.; McGhee, C. A.; Marouf, E. A.; Rappaport, N.

    2006-09-01

    Planetary rings provide a remarkable laboratory for the investigation of a wide range of dynamical effects, including resonance-driven density and bending waves, satellite wakes, shepherding of narrow ringlets, and non-circular edges of gaps. Careful quantitative examination of these features requires a very accurate absolute radius scale and planetary pole direction, achievable by combining multiple stellar and radio occultation observations. Uncertainty in the location of the spacecraft (at the km level) introduces a fundamental uncertainty into the geometric solution for the ring radius scale, and in the end one must solve for corrections to the spacecraft trajectory as part of the overall determination of the ring orbital model. Using JPL's NAIF toolkit, we have developed accurate algorithms for computing the event time of a ring occultation during an Earth-based or spacecraft occultation, including the effects of spacecraft trajectory errors mapped in two orthogonal directions transverse to the line of sight, based on osculating orbital elements for the instantaneous spacecraft path. These are the fundamental building blocks for a global solution for the pole direction and orbits of the rings of Saturn and Uranus. For Uranus, our new orbit solution includes the full set of digitally recorded occultation data from 1977-2002, yielding a radius scale accurate at the 100 meter level. For Saturn, we explore the potential for highly accurate ring orbit determination as occultation observations from dozens of stellar and radio occultations become publicly available over the course of the ongoing Cassini orbital tour. Saturn's pole precession is also detectable from ring occultation data, and we set limits on the accuracy of the precession rate determination and the implications for our understanding of the mass distribution in Saturn's interior. This work was supported in part by the NASA PGG program.

  6. AdvancED Flex 4

    CERN Document Server

    Tiwari, Shashank; Schulze, Charlie

    2010-01-01

    AdvancED Flex 4 makes advanced Flex 4 concepts and techniques easy. Ajax, RIA, Web 2.0, mashups, mobile applications, the most sophisticated web tools, and the coolest interactive web applications are all covered with practical, visually oriented recipes. * Completely updated for the new tools in Flex 4* Demonstrates how to use Flex 4 to create robust and scalable enterprise-grade Rich Internet Applications.* Teaches you to build high-performance web applications with interactivity that really engages your users.* What you'll learn Practiced beginners and intermediate users of Flex, especially

  7. Beam Control and Steering in the University of Maryland Electron Ring (UMER)

    International Nuclear Information System (INIS)

    The University of Maryland Electron Ring (UMER) is a low energy, high current recirculator for beam physics research. Ring construction has been completed for multi-turn operation of beams over a broad range of intensities and initial conditions. The electron beam current is adjustable up to 100 mA and pulse length as long as 100 ns. UMER is addressing issues in beam physics relevant to many applications that require intense beams of high quality, such as advanced concept accelerators, free electron lasers, spallalion neutron sources, and future heavy-ion drivers for inertial fusion. The primary focus of this presentation is experimental results in the area of beam steering and control within the injection line and ring. Unique beam steering algorithms now include measurement of the beam response matrix at each quadrupole and matrix inversion by singular value decomposition (SVD). With these advanced steering methods, transport of an intense beam over 50 turns (3600 full lattice periods) of the ring has been achieved

  8. Beam Control and Steering in the University of Maryland Electron Ring (UMER)

    Science.gov (United States)

    Walter, M.; Bai, G.; Bernal, S.; Feldman, D.; Godlove, T.; Haber, I.; Holloway, M.; Kishek, R.; O'Shea, P.; Papadopoulos, C.; Quinn, B.; Reiser, M.; Stratakis, D.; Sutter, D.; Thangaraj, J.; Wilson, M.; Wu, C.

    2006-11-01

    The University of Maryland Electron Ring (UMER) is a low energy, high current recirculator for beam physics research. Ring construction has been completed for multi-turn operation of beams over a broad range of intensities and initial conditions. The electron beam current is adjustable up to 100 mA and pulse length as long as 100 ns. UMER is addressing issues in beam physics relevant to many applications that require intense beams of high quality, such as advanced concept accelerators, free electron lasers, spallalion neutron sources, and future heavy-ion drivers for inertial fusion. The primary focus of this presentation is experimental results in the area of beam steering and control within the injection line and ring. Unique beam steering algorithms now include measurement of the beam response matrix at each quadrupole and matrix inversion by singular value decomposition (SVD). With these advanced steering methods, transport of an intense beam over 50 turns (3600 full lattice periods) of the ring has been achieved.

  9. Energy transfer between a passing vortex ring and a flexible plate in an ideal quiescent fluid

    Energy Technology Data Exchange (ETDEWEB)

    Hu, JiaCheng; Peterson, Sean D., E-mail: peterson@mme.uwaterloo.ca [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Porfiri, Maurizio [Department of Mechanical and Aerospace Engineering, New York University Polytechnic School of Engineering, Brooklyn, New York 11201 (United States)

    2015-09-21

    Recent advancements in highly deformable smart materials have lead to increasing interest in small-scale energy harvesting research for powering low consumption electronic devices. One such recent experimental study by Goushcha et al. explored energy harvesting from a passing vortex ring by a cantilevered smart material plate oriented parallel to and offset from the path of the ring in an otherwise quiescent fluid. The present study focuses on modeling this experimental study using potential flow to facilitate optimization of the energy extraction from the passing ring to raise the energy harvesting potential of the device. The problem is modeled in two-dimensions with the vortex ring represented as a pair of counter-rotating free vortices. Vortex pair parameters are determined to match the convection speed of the ring in the experiments, as well as the imposed pressure loading on the plate. The plate is approximated as a Kirchhoff-Love plate and represented as a finite length vortex sheet in the fluid domain. The analytical model matches experimental measurements, including the tip displacement, the integrated force along the entire plate length as a function of vortex ring position, and the pressure along the plate. The potential flow solution is employed in a parametric study of the governing dimensionless parameters in an effort to guide the selection of plate properties for optimal energy harvesting performance. Results of the study indicate an optimal set of plate properties for a given vortex ring configuration, in which the time-scale of vortex advection matches that of the plate vibration.

  10. Energy transfer between a passing vortex ring and a flexible plate in an ideal quiescent fluid

    International Nuclear Information System (INIS)

    Recent advancements in highly deformable smart materials have lead to increasing interest in small-scale energy harvesting research for powering low consumption electronic devices. One such recent experimental study by Goushcha et al. explored energy harvesting from a passing vortex ring by a cantilevered smart material plate oriented parallel to and offset from the path of the ring in an otherwise quiescent fluid. The present study focuses on modeling this experimental study using potential flow to facilitate optimization of the energy extraction from the passing ring to raise the energy harvesting potential of the device. The problem is modeled in two-dimensions with the vortex ring represented as a pair of counter-rotating free vortices. Vortex pair parameters are determined to match the convection speed of the ring in the experiments, as well as the imposed pressure loading on the plate. The plate is approximated as a Kirchhoff-Love plate and represented as a finite length vortex sheet in the fluid domain. The analytical model matches experimental measurements, including the tip displacement, the integrated force along the entire plate length as a function of vortex ring position, and the pressure along the plate. The potential flow solution is employed in a parametric study of the governing dimensionless parameters in an effort to guide the selection of plate properties for optimal energy harvesting performance. Results of the study indicate an optimal set of plate properties for a given vortex ring configuration, in which the time-scale of vortex advection matches that of the plate vibration

  11. Design of Hierarchical Ring Networks Using Branch-and-Price

    DEFF Research Database (Denmark)

    Thomadsen, Tommy; Stidsen, Thomas K.

    2004-01-01

    We consider the problem of designing hierarchical two layer ring networks. The top layer consists of a federal-ring which establishes connection between a number of node disjoint metro-rings in a bottom layer. The objective is to minimize the costs of links in the network, taking both the fixed...... link establishment costs and the link capacity costs into account. The hierarchical two layer ring network design problem is solved in two stages: First the bottom layer, i.e. the metro-rings are designed, implicitly taking into account the capacity cost of the federal-ring. Then the federal......-ring is designed connecting the metro-rings, minimizing fixed link establishment costs of the federal-ring. A branch-and-price algorithm is presented for the design of the bottom layer and it is suggested that existing methods are used for the design of the federal-ring. Computational results are given...

  12. Climate variability of Late Pleistocene deglaciation in the North American midcontinent derived from tree rings

    Science.gov (United States)

    Panyushkina, Irina P.; Livina, Valerie N.; Leavitt, Steve W.; Mode, William N.

    2016-04-01

    (Green Bay ice lobe re-advance). We discuss how the detected bifurcation events in tree-ring data track a reversing temperature regime from warming to cooling as reported at regional (North American midcontinent) and northern hemispheric scales. The study contributes greatly to exploring the potential of Late Glacial tree rings to unveil the dynamics of regional to hemispheric temperatures of the Bølling-Allerød interstadial. References: [1] Panyushkina & Leavitt, CJFR 2013; [2] Livina & Lenton, GRL 2007; [3] Livina et al, Climate of the Past 2010; [4] Livina et al, Physica A 2013.

  13. How does the blue-ringed octopus (Hapalochlaena lunulata) flash its blue rings?

    Science.gov (United States)

    Mäthger, Lydia M; Bell, George R R; Kuzirian, Alan M; Allen, Justine J; Hanlon, Roger T

    2012-11-01

    The blue-ringed octopus (Hapalochlaena lunulata), one of the world's most venomous animals, has long captivated and endangered a large audience: children playing at the beach, divers turning over rocks, and biologists researching neurotoxins. These small animals spend much of their time in hiding, showing effective camouflage patterns. When disturbed, the octopus will flash around 60 iridescent blue rings and, when strongly harassed, bite and deliver a neurotoxin that can kill a human. Here, we describe the flashing mechanism and optical properties of these rings. The rings contain physiologically inert multilayer reflectors, arranged to reflect blue-green light in a broad viewing direction. Dark pigmented chromatophores are found beneath and around each ring to enhance contrast. No chromatophores are above the ring; this is unusual for cephalopods, which typically use chromatophores to cover or spectrally modify iridescence. The fast flashes are achieved using muscles under direct neural control. The ring is hidden by contraction of muscles above the iridophores; relaxation of these muscles and contraction of muscles outside the ring expose the iridescence. This mechanism of producing iridescent signals has not previously been reported in cephalopods and we suggest that it is an exceptionally effective way to create a fast and conspicuous warning display.

  14. Construction of carbocyclic ring of indoles using ruthenium-catalyzed ring-closing olefin metathesis.

    Science.gov (United States)

    Yoshida, Kazuhiro; Hayashi, Kazushi; Yanagisawa, Akira

    2011-09-16

    The selective synthesis of substituted indoles was achieved by the ring-closing olefin metathesis (RCM)/elimination sequence or the RCM/tautomerization sequence of functionalized pyrrole precursors. The RCM/elimination sequence was also applied to double ring closure to yield a substituted carbazole.

  15. Analytical model for double split ring resonators with arbitrary ring width

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Jensen, Thomas; Krozer, Viktor;

    2008-01-01

    For the first time, the analytical model for a double split ring resonator with unequal width rings is developed. The proposed models for the resonators with equal and unequal widths are based on an impedance matrix representation and provide the prediction of performance in a wide frequency range...

  16. Curious terminal turn of rolling rings

    CERN Document Server

    Jalali, Mir Abbas; Alam, Reza

    2014-01-01

    We report an unexpected reverse spiral turn in the final stage of the motion of rolling rings. It is well known that spinning disks have definite centers of rotation until they stop. While a spinning ring starts its motion with a similar kinematics, moving along a cycloidal path prograde with the direction of its rigid body rotation, the mean trajectory of its center of mass develops an inflection point so that the ring makes a spiral turn and revolves in a retrograde direction around a new center. Using high speed imaging and numerical simulations of models featuring a rolling rigid body, we show that the hollow geometry of a ring tunes the rotational air drag resistance so that the frictional force at the contact point with the ground changes its direction at the inflection point and puts the ring on a retrograde spiral trajectory. Our findings have potential applications in designing topologically new surface-effect flying objects capable of performing complex reorientation and translational maneuvers.

  17. Reconfigurable ring filter with controllable frequency response.

    Science.gov (United States)

    Ab Wahab, Norfishah; Mohd Salleh, Mohd Khairul; Ismail Khan, Zuhani; Abd Rashid, Nur Emileen

    2014-01-01

    Reconfigurable ring filter based on single-side-access ring topology is presented. Using capacitive tuning elements, the electrical length of the ring can be manipulated to shift the nominal center frequency to a desired position. A synthesis is developed to determine the values of the capacitive elements. To show the advantage of the synthesis, it is applied to the reconfigurable filter design using RF lumped capacitors. The concept is further explored by introducing varactor-diodes to continuously tune the center frequency of the ring filter. For demonstration, two prototypes of reconfigurable ring filters are realized using microstrip technology, simulated, and measured to validate the proposed concept. The reconfigured filter using lumped elements is successfully reconfigured from 2 GHz to 984.4 MHz and miniaturized by 71% compared to the filter directly designed at the same reconfigured frequency, while, for the filter using varactor-diodes, the frequency is chosen from 1.10 GHz to 1.38 GHz spreading over 280 MHz frequency range. Both designs are found to be compact with acceptable insertion loss and high selectivity. PMID:25121132

  18. Storage rings for radioactive ion beams

    Science.gov (United States)

    Nolden, F.; Dimopoulou, C.; Dolinskii, A.; Steck, M.

    2008-10-01

    Storage rings for radioactive heavy ions can be applied for a wide range of experiments in atomic and nuclear physics. The rare isotope beams are produced in flight via fragmentation or fission of high-intensity primary ions and they circulate in the storage ring at moderately relativistic energies (typically between 0.1 GeV/u up to 1 GeV/u). Due to their production mechanism they are usually highly charged or even fully stripped. The circulating radioactive heavy ion beams can be used to measure nuclear properties such as masses and decay times, which, in turn, can depend strongly on the ionic charge state. The storage rings must have large acceptances and dynamic apertures. The subsequent application of stochastic precooling of the secondary ions which are injected with large transverse and longitudinal emittances, and electron cooling to reach very high phase space densities has turned out to be a helpful tool for experiments with short-lived ions having lifetimes down to a few seconds. Some of these experiments have already been performed at the experimental storage ring ESR at GSI. The storage ring complex of the FAIR project is intended to enhance significantly the range of experimental possibilities. It is planned to extend the scope of experimental possibilities to collisions with electron or antiproton beams.

  19. Chromatin ring formation at plant centromeres

    Directory of Open Access Journals (Sweden)

    Veit eSchubert

    2016-02-01

    Full Text Available We observed the formation of chromatin ring structures at centromeres of somatic rye and Arabidopsis chromosomes. To test whether this behavior is present also in other plant species and tissues we analyzed Arabidopsis, rye, wheat, Aegilops and barley centromeres during cell divisions and in interphase nuclei by immunostaining and FISH. Furthermore, structured illumination microscopy (super-resolution was applied to investigate the ultrastructure of centromere chromatin beyond the classical refraction limit of light. It became obvious, that a ring formation at centromeres may appear during mitosis, meiosis and in interphase nuclei in all species analyzed. However, varying centromere structures, as ring formations or globular organized chromatin fibers, were identified in different tissues of one and the same species. In addition, we found that a chromatin ring formation may also be caused by subtelomeric repeats in barley. Thus, we conclude that the formation of chromatin rings may appear in different plant species and tissues, but that it is not specific for centromere function. Based on our findings we established a model describing the ultrastructure of plant centromeres and discuss it in comparison to previous models proposed for animals and plants.

  20. On Pasting and Reversing operations over some rings

    CERN Document Server

    Acosta-Humanez, Primitivo Belen; Sanchez, Angela Mariette Rodriguez

    2010-01-01

    In this paper we study two operations, Pasting and Reversing, defined from a natural way to be applied over some rings such as the ring of polynomials and the ring of linear differential operators, which is a differential ring. We obtain some properties of these operations over these rings, in particular over the set of natural numbers, in where we rewrite some properties incoming from recreational mathematics.

  1. Linear groups over a locally linear division ring

    CERN Document Server

    Hai, Bui Xuan; Deo, Trinh Thanh

    2010-01-01

    In this paper, in the first we give definitions of some classes of division rings which strictly contain the class of centrally finite division rings. One of our main purpose is to construct non-trivial examples of rings of new defined classes. Further, we study linear groups over division rings of these classes. Our new obtained results generalize precedent results for centrally finite division rings.

  2. Levitating states of superconducting rings in the field of a fixed ring with constant current

    Science.gov (United States)

    Bishaev, A. M.; Bush, A. A.; Gavrikov, M. B.; Denisyuk, A. I.; Kamentsev, K. E.; Kozintseva, M. V.; Savel'ev, V. V.; Sigov, A. S.

    2014-06-01

    We consider the possibility of designing a plasma trap with a magnetic system formed by super-conducting rings and coils levitating in the field of a fixed coaxial coil carrying constant current. An analytic dependence of the potential energy of such a system with one or two levitating superconducting rings having trapped preset magnetic fluxes on their coordinates in the uniform gravitational field is obtained in the thin ring approximation. Calculations performed in the Mathcad system show that equilibrium states of such a system exist for certain values of parameters. Levitating states of a single superconducting ring and two superconducting rings in the field of the coil with constant current are observed experimentally in positions corresponding to calculated values.

  3. Ultra-Sensitive Chip-Based Photonic Temperature Sensor Using Ring Resonator Structures

    OpenAIRE

    Xu, Haitan; Hafezi, Mohammad; Fan, J.; Taylor, J. M.; Strouse, G. F.; Ahmed, Zeeshan

    2013-01-01

    Resistance thermometry provides a time-tested method for taking temperature measurements. However, fundamental limits to resistance-based approaches has produced considerable interest in developing photonic temperature sensors to leverage advances in frequency metrology and to achieve greater mechanical and environmental stability. Here we show that silicon-based optical ring resonator devices can resolve temperature differences of 1 mK using the traditional wavelength scanning methodology. A...

  4. A hetero-structured ring discovered by CAS nano-scientists

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Teaming up with co-workers,researchers from the CAS-affiliated National Center for Nanoscience and Technology(NCNST) recently succeeded in fabricating a hetero-structured nano-ring in their laboratory. The feat, scientist believe, would be valuable for developing new optical or electronic nano-elements and related devices in the near future.The work was recently reported by Advanced Materials (Vol. 19, 2319-2323, 2007).

  5. Baby Steps in Quantum Ring Theory: towards a background independent framework for Quantum Gravity

    OpenAIRE

    Araya-Gochez, Rafael A.

    2016-01-01

    We investigate gravity as a gauge theory in the language of fiber bundles with tools from algebraic geometry. Compelled by the construction of the Eilenberg-MacLane classifying space via Fox derivations in an integral group ring, the origin of locally curved spacetime as a an abelian group extension is sought algebraically by means of a suitable derivation rule that conforms with the algebraic content of Einstein's equation. Accordingly, a peculiar flavor of background independence is advance...

  6. Visible upconversion fiber lasers in ring configuration

    Science.gov (United States)

    Caspary, Reinhard; Baraniecki, Tomasz P.; Kozak, Marcin M.; Kowalsky, Wolfgang

    2005-09-01

    Up-conversion fiber lasers based on Pr3+/Yb3+ doped fluoride fibers and pumped at 835 nm can operate on emission lines in the red, orange, green, and blue spectral region. Up to now only Fabry-Perot configurations with two mirrors butt-coupled to the fiber ends were investigated. In this paper we present the first visible Pr3+/Yb3+ fiber lasers in a ring configuration. In contrast to the usual Fabry-Perot configuration, the basic ring resonator setup contains no free-space optics and no parts which need to be adjusted. The main challenge for such a setup is the connection between the fluoride laser fiber and the remaining part of the ring resonator, which is made from silica fibers. Due to the very different melting temperatures of both glasses usual fusion splices are impossible. We use a special technique to couple the fibers with glue.

  7. Young star clusters in circumnuclear starburst rings

    CERN Document Server

    de Grijs, Richard; Jia, Siyao; Ho, Luis C; Anders, Peter

    2016-01-01

    We analyse the cluster luminosity functions (CLFs) of the youngest star clusters in three galaxies exhibiting prominent circumnuclear starburst rings. We focus specifically on NGC 1512 and NGC 6951, for which we have access to H$\\alpha$ data that allow us to unambiguously identify the youngest sample clusters. To place our results on a firm statistical footing, we first explore in detail a number of important technical issues affecting the process from converting the observational data into the spectral-energy distributions of the objects in our final catalogues. The CLFs of the young clusters in both galaxies exhibit approximate power-law behaviour down to the 90 per cent observational completeness limits, thus showing that star cluster formation in the violent environments of starburst rings appears to proceed similarly as that elsewhere in the local Universe. We discuss this result in the context of the density of the interstellar medium in our starburst-ring galaxies.

  8. 3rd Low Emittance Ring Workshop

    CERN Document Server

    2013-01-01

    The workshop brings together different accelerator communities working on the design of ultra low emittance lattices such as synchrotron light sources, damping rings and test facilities for linear colliders and HEP circular colliders. The aim of the workshop is to review the present development s in design of ultra low emittance lattices, the experience and the challenges with the operation of low emittance synchrotrons and the main technological problems. The merging of different accelerator communities is expected to foster ideas exchange and the collaboration both on theoretical, experimental and design issues. Areas for common R programmes will be explored. The workshop will profit from the experience of colleagues who have designed, commissioned and operated lepton ring colliders and synchrotron light sources as well as from the ones involved in future low emittance upgrade programmes of existing rings.

  9. Construction of compact electron storage ring JSR

    Science.gov (United States)

    Yokomizo, H.; Yanagida, K.; Sasaki, S.; Harami, T.; Konishi, H.; Mashiko, K.; Ashida, K.; Harada, S.; Hashimoto, H.; Iizuka, M.; Kabasawa, M.; Nakayama, K.; Yamada, K.; Suzuki, Y.

    1989-07-01

    A compact electron storage ring (JSR) is under construction in order to study accelerator technologies and to be used as the test ring aiming at a highly brilliant synchrotron radiation facility (6-8 GeV). The JSR lattice is a double-focusing achromatic type. The circumference is 20.5 m. However, even in this small ring, one straight section with a length of ˜1.5 m, where the dispersion is free, is provided for the insertion device study. The electron beam is supplied by the linac with an energy of 150 MeV, and the stored energy is slowly increased up to 300 MeV. Power supplies of all magnets and the rf system are controlled by a real-time computer through optical fiber links, and signals of beam monitors are stored in the same computer so that it is easy to test any type of control procedures.

  10. Construction of compact electron storage ring JSR

    International Nuclear Information System (INIS)

    A compact electron storage ring (JSR) is under construction in order to study accelerator technologies and to be used as the test ring aiming at a highly brilliant synchrotron radiation facility (6--8 GeV). The JSR lattice is a double-focusing achromatic type. The circumference is 20.5 m. However, even in this small ring, one straight section with a length of ∼1.5 m, where the dispersion is free, is provided for the insertion device study. The electron beam is supplied by the linac with an energy of 150 MeV, and the stored energy is slowly increased up to 300 MeV. Power supplies of all magnets and the rf system are controlled by a real-time computer through optical fiber links, and signals of beam monitors are stored in the same computer so that it is easy to test any type of control procedures

  11. On Learning Ring-Sum-Expansions

    DEFF Research Database (Denmark)

    Fischer, Paul; Simon, H. -U.

    1992-01-01

    The problem of learning ring-sum-expansions from examples is studied. Ring-sum-expansions (RSE) are representations of Boolean functions over the base {#123;small infinum, (+), 1}#125;, which reflect arithmetic operations in GF(2). k-RSE is the class of ring-sum-expansions containing only monomials...... be learned from positive (negative) examples alone. However, if the restriction that the hypothesis which is output by the learning algorithm is also a k-RSE is suspended, then k-RSE is learnable from positive (negative) examples only. Moreover, it is proved that 2-term-RSE is learnable by a conjunction...... of a 2-CNF and a 1-DNF. Finally the paper presents learning (on-line prediction) algorithms for k-RSE that are optimal with respect to the sample size (worst case mistake bound)...

  12. Gorenstein flatness and injectivity over Gorenstein rings

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Let R be a Gorenstein ring.We prove that if I is an ideal of R such that R/I is a semi-simple ring,then the Gorenstein flat dimension of R/I as a right R-module and the Gorenstein injective dimension of R/I as a left R-module are identical.In addition,we prove that if R→S is a homomorphism of rings and SE is an injective cogenerator for the category of left S-modules,then the Gorenstein flat dimension of S as a right R-module and the Gorenstein injective dimension of E as a left R-module are identical.We also give some applications of these results.

  13. A difference ring theory for symbolic summation☆

    Science.gov (United States)

    Schneider, Carsten

    2016-01-01

    A summation framework is developed that enhances Karr's difference field approach. It covers not only indefinite nested sums and products in terms of transcendental extensions, but it can treat, e.g., nested products defined over roots of unity. The theory of the so-called RΠΣ⁎-extensions is supplemented by algorithms that support the construction of such difference rings automatically and that assist in the task to tackle symbolic summation problems. Algorithms are presented that solve parameterized telescoping equations, and more generally parameterized first-order difference equations, in the given difference ring. As a consequence, one obtains algorithms for the summation paradigms of telescoping and Zeilberger's creative telescoping. With this difference ring theory one gets a rigorous summation machinery that has been applied to numerous challenging problems coming, e.g., from combinatorics and particle physics. PMID:26726284

  14. 'Optimal' vortex rings and aquatic propulsion mechanisms

    Science.gov (United States)

    Linden, Paul; Turner, Stewart

    2004-11-01

    Fish swim by flapping their tail and other fins. Other sea creatures, such as squid and salps, eject fluid intermittently as a jet. We discuss the fluid mechanics behind these propulsion mechanisms, and show that these animals produce optimal vortex rings, which give the maximum thrust for a given energy input. We show fish optimise both their steady swimming and their ability to accelerate and turn by producing an individual optimal ring with each flap of the tail or fin. Salps produce vortex rings directly by ejecting a volume of fluid through a rear orifice, and these are also optimal. An important implication of this paper is that the repetition of vortex production is not necessary for an individual vortex to have the `optimal' characteristics.

  15. An axisymmetric steady state vortex ring model

    CERN Document Server

    Wang, Ruo-Qian

    2016-01-01

    Based on the solution of Atanasiu et al. (2004), a theoretical model for axisymmetric vortex flows is derived in the present study by solving the vorticity transport equation for an inviscid, incompressible fluid in cylindrical coordinates. The model can describe a variety of axisymmetric flows with particular boundary conditions at a moderately high Reynolds number. This paper shows one example: a high Reynolds number laminar vortex ring. The model can represent a family of vortex rings by specifying the modulus function using a Rayleigh distribution function. The characteristics of this vortex ring family are illustrated by numerical methods. For verification, the model results compare well with the recent direct numerical simulations (DNS) in terms of the vorticity distribution and streamline patterns, cross-sectional areas of the vortex core and bubble, and radial vorticity distribution through the vortex center. Most importantly, the asymmetry and elliptical outline of the vorticity profile are well capt...

  16. Computerspil og læring

    DEFF Research Database (Denmark)

    Larsen, Lasse Juel

    2015-01-01

    Game-based learning og gamification er ord, der ofte optræder i forbindelse med computerspil og læring. Denne artikel vil analytisk undersøge, hvordan computerspil og læring går i forbindelse med hinanden. Artikel tager afsæt i Gregory Batesons læringsteori og læser denne igennem det kommercielle...... computerspil StarCraft 2 fra Blizzard Intertainment. Batesons læringsteori vil ikke alene blive gennemgået, men også udvidet og perspektiveret. Formålet med denne indsats er at skabe et afsæt, der kan demonstrere, hvordan læring foregår i computerspil. Herefter vil afsættet blive anvendt til at destillere et...

  17. Amplitude-modulated fiber-ring laser

    DEFF Research Database (Denmark)

    Caputo, J. G.; Clausen, Carl A. Balslev; Sørensen, Mads Peter;

    2000-01-01

    Soliton pulses generated by a fiber-ring laser are investigated by numerical simulation and perturbation methods. The mathematical modeling is based on the nonlinear Schrödinger equation with perturbative terms. We show that active mode locking with an amplitude modulator leads to a self-starting......Soliton pulses generated by a fiber-ring laser are investigated by numerical simulation and perturbation methods. The mathematical modeling is based on the nonlinear Schrödinger equation with perturbative terms. We show that active mode locking with an amplitude modulator leads to a self......-starting of stable solitonic pulses from small random noise, provided the modulation depth is small. The perturbative analysis leads to a nonlinear coupled return map for the amplitude, phase, and position of the soliton pulses circulating in the fiber-ring laser. We established the validity of this approach...

  18. Centaur's ring system formation by close encounters

    Science.gov (United States)

    De Santana, Thamiris; Winter, Othon

    2016-10-01

    Rupture of small bodies due to close approach to a massive body is a frequent event in the Solar System. Some of these small bodies can just disintegrate completely or suffer a material loss.In this work we study the gravitational interaction between a giant planet and a small body in close encounters in order to simulate the formation of a planetary ring system around a centaur by the partial rupture of the small body.Considering the current Chariklo's body and a disk of particles around it, we simulated the system under close encounters with one of giant planets.Another motivation for the study is also the centaur Chiron, that is a candidate to have a ring system like Chariklo. The characteristics of the encounters are defined by the impact parameter and the velocity at infinity.The results are presented in terms of conditions that could lead to a rupture that could generate a ring like system.

  19. Traffic Grooming in Bidirectional WDM Ring Networks

    CERN Document Server

    Bermond, Jean-Claude; Valls, Ignasi Sau

    2009-01-01

    We study the minimization of ADMs (Add-Drop Multiplexers) in optical WDM bidirectional rings considering symmetric shortest path routing and all-to-all unitary requests. We precisely formulate the problem in terms of graph decompositions, and state a general lower bound for all the values of the grooming factor $C$ and $N$, the size of the ring. We first study exhaustively the cases C=1, $C = 2$, and C=3, providing improved lower bounds, optimal constructions for several infinite families, as well as asymptotically optimal constructions and approximations. We then study the case $C>3$, focusing specifically on the case $C = k(k+1)/2$ for some $k \\geq 1$. We give optimal decompositions for several congruence classes of $N$ using the existence of some combinatorial designs. We conclude with a comparison of the cost functions in unidirectional and bidirectional WDM rings.

  20. Numerical Simulation of Piston Ring Lubrication

    DEFF Research Database (Denmark)

    Felter, Christian Lotz

    2006-01-01

    This paper describes a numerical method that can be used to model the lubrication of piston rings. Classical lubrication theory is based on the Reynolds equation which is ap- plicable to confined geometries and open geometries where the flooding conditions are known. Lubrication of piston rings......, however, fall outside this category of problems since the piston rings might suffer from starved running conditions. This means that the com- putational domain where Reynold equation is applicable (including a cavitation criteria) is unknown. In order to overcome this problem the computational domain...... variables u, v, rho for the velocity components and density, respectively. Time integration is performed by a third order Runge-Kutta method. The set of equations is closed by the Dowson- Higginson equation for the relation between density and pressure. Boundary conditions are the non-slip condition...

  1. PREFACE: Special section on vortex rings Special section on vortex rings

    Science.gov (United States)

    Fukumoto, Yasuhide

    2009-10-01

    This special section of Fluid Dynamics Research includes five articles on vortex rings in both classical and quantum fluids. The leading scientists of the field describe the trends in and the state-of-the-art development of experiments, theories and numerical simulations of vortex rings. The year 2008 was the 150th anniversary of 'vortex motion' since Hermann von Helmholtz opened up this field. In 1858, Helmholtz published a paper in Crelle's Journal which put forward the concept of 'vorticity' and made the first analysis of vortex motion. Fluid mechanics before that was limited to irrotational motion. In the absence of vorticity, the motion of an incompressible homogeneous fluid is virtually equivalent to a rigid-body motion in the sense that the fluid motion is determined once the boundary configuration is specified. Helmholtz proved, among other things, that, without viscosity, a vortex line is frozen into the fluid. This Helmholtz's law immediately implies the preservation of knots and links of vortex lines and its implication is enormous. One of the major trends of fluid mechanics since the latter half of the 20th century is to clarify the topological meaning of Helmholtz's law and to exploit it to develop theoretical and numerical methods to find the solutions of the Euler equations and to develop experimental techniques to gain an insight into fluid motion. Vortex rings are prominent coherent structures in a variety of fluid motions from the microscopic scale, through human and mesoscale to astrophysical scales, and have attracted people's interest. The late professor Philip G Saffman (1981) emphasized the significance of studies on vortex rings. One particular motion exemplifies the whole range of problems of vortex motion and is also a commonly known phenomenon, namely the vortex ring or smoke ring. Vortex rings are easily produced by dropping drops of one liquid into another, or by puffing fluid out of a hole, or by exhaling smoke if one has the skill

  2. Ring galaxies as the cradle for ULXs

    Science.gov (United States)

    Wolter, Anna

    2015-08-01

    Ring galaxies are unique laboratories where the effects of galaxy interactions can be studied and the final stages of stellar evolution investigated. They are characterized by high star formation rates (SFR) and low metallicity, which favours the formation of high mass remnants. The few ring galaxies for which high resolution X-ray data are available show enhanced X-ray emission, and large numbers of Ultraluminous X-ray sources (ULXs). Due to the peculiar morphology of ring galaxies, detected point sources in the ring are very likely to be physically associated with the galaxy, reducing the problem of contamination from spurious sources which affects other samples. However the evidence in the X-ray band is based on a very scanty sample of four galaxies.In order to find an unbiased sample with which to compare these findings, we have selected all the peculiar galaxies labelled as collisional rings with a spectroscopic redshift z<0.02 from the Arp & Madore `Catalogue of southern peculiar galaxies and associations'. This selection produces a sample of 12 galaxies which we have observed with Chandra and XMM-Newton. We will discuss the results of these observations and support for current models that propose low metallicity environments as the ideal cradle for ULXs. We will compare the results from this statistically selected sample with those from brighter and known ring galaxies in order to asses the likelihood to find IMBHs due to collision events. We will address the presence of other signs of interaction, from high SFR to multiwavelenght morphology and spectra (eg. IR, Halpha..).

  3. Advanced calculus

    CERN Document Server

    Nickerson, HK; Steenrod, NE

    2011-01-01

    ""This book is a radical departure from all previous concepts of advanced calculus,"" declared the Bulletin of the American Mathematics Society, ""and the nature of this departure merits serious study of the book by everyone interested in undergraduate education in mathematics."" Classroom-tested in a Princeton University honors course, it offers students a unified introduction to advanced calculus. Starting with an abstract treatment of vector spaces and linear transforms, the authors introduce a single basic derivative in an invariant form. All other derivatives - gradient, divergent, curl,

  4. A new storage-ring light source

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Alex [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-06-01

    A recently proposed technique in storage ring accelerators is applied to provide potential high-power sources of photon radiation. The technique is based on the steady-state microbunching (SSMB) mechanism. As examples of this application, one may consider a high-power DUV photon source for research in atomic and molecular physics or a high-power EUV radiation source for industrial lithography. A less challenging proof-of-principle test to produce IR radiation using an existing storage ring is also considered.

  5. Ring vortex solitons in nonlocal nonlinear media

    DEFF Research Database (Denmark)

    Briedis, D.; Petersen, D.E.; Edmundson, D.;

    2005-01-01

    We study the formation and propagation of two-dimensional vortex solitons, i.e. solitons with a phase singularity, in optical materials with a nonlocal focusing nonlinearity. We show that nonlocality stabilizes the dynamics of an otherwise unstable vortex beam. This occurs for either single...... or higher charge fundamental vortices as well as higher order (multiple ring) vortex solitons. Our results pave the way for experimental observation of stable vortex rings in other nonlocal nonlinear systems including Bose-Einstein condensates with pronounced long-range interparticle interaction....

  6. The BRAHMS ring imaging Cherenkov detector

    Science.gov (United States)

    Debbe, R.; Jørgensen, C. E.; Olness, J.; Yin, Z.

    2007-01-01

    A Ring Imaging Cherenkov detector built for the BRAHMS experiment at the Brookhaven RHIC is described. This detector has a high index of refraction gas radiator. Cherenkov light is focused on a photo-multiplier based photon detector with a large spherical mirror. The combination of momentum and ring radius measurement provides particle identification from 2.5 to 35 GeV/ c for pions and kaons and well above 40 GeV/ c for protons during runs that had the radiator index of refraction set at n-1=1700×10-6.

  7. Recent results in Ring Diagram analysis

    OpenAIRE

    Rabello-Soares, M. Cristina

    2013-01-01

    The ring-diagram technique was developed by Frank Hill 25 years ago and developed quickly during the late 1990s. It is nowadays one of the most commonly used techniques in local helioseismology. The method consists in the power spectral analysis of solar acoustic oscillations on small regions (2 to 30 degrees) of the solar surface. The power spectrum resembles a set of trumpets nested inside each other and, for a given frequency, it looks like a ring, hence the technique's name. It provides i...

  8. Fixed points and fusion rings. Part 1

    OpenAIRE

    Beltaos, Elaine

    2011-01-01

    In the first of this two-part series, we find `fixed point factorisation' formulas, towards an understanding of the fusion ring of WZW models. Fixed-point factorisation refers to the simplifications in the data of a CFT involving primary fields fixed by simple-currents. Until now, it has been worked out only for SU(n), where it has developed into a powerful tool for understanding the fusion rings of WZW models of CFT -- e.g. it has lead to closed formulas for NIM-reps and D-brane charges and ...

  9. Chromatic corrections for large storage rings

    International Nuclear Information System (INIS)

    The use of achromat concept (1) to facilitate chromatic corrections in large storage rings is illustrated. The example given in this report is a lattice for a 75 GeV/c ring with six interaction regions having a beta x = 1.6 m, a beta y = 0.1 m and a luminosity of 1.4 1032 cm-2s-1. The chromatic corrections are done with four families of sextupoles, two for each transverse plane, the strengths of which are determined by the solution of four linear equations in four unknowns. The basic simplicity of the method allows on-line control of the sextupole adjustments

  10. Coherent spaces, Boolean rings and quantum gates

    Science.gov (United States)

    Vourdas, A.

    2016-10-01

    Coherent spaces spanned by a finite number of coherent states, are introduced. Their coherence properties are studied, using the Dirac contour representation. It is shown that the corresponding projectors resolve the identity, and that they transform into projectors of the same type, under displacement transformations, and also under time evolution. The set of these spaces, with the logical OR and AND operations is a distributive lattice, and with the logical XOR and AND operations is a Boolean ring (Stone's formalism). Applications of this Boolean ring into classical CNOT gates with n-ary variables, and also quantum CNOT gates with coherent states, are discussed.

  11. Computers in nonassociative rings and algebras

    CERN Document Server

    Beck, Robert E

    1977-01-01

    Computers in Nonassociative Rings and Algebras provides information pertinent to the computational aspects of nonassociative rings and algebras. This book describes the algorithmic approaches for solving problems using a computer.Organized into 10 chapters, this book begins with an overview of the concept of a symmetrized power of a group representation. This text then presents data structures and other computational methods that may be useful in the field of computational algebra. Other chapters consider several mathematical ideas, including identity processing in nonassociative algebras, str

  12. Biopolymers and the fellowship of DNA rings.

    Science.gov (United States)

    Wang, James C

    2013-12-01

    This article presents a brief account of the historical backdrop of the study of interlocked DNA rings (DNA catenanes), their formation in cells, and the importance of resolving the component rings of an intracellular DNA catenane if they are to be properly partitioned into a pair of progeny cells. In humans, for example, aberrant segregation of intertwined chromosomes is a major cause of birth defects, as well as termination of pregnancy in utero. Some yet unresolved issues of DNA catenation, including plausible structural and/or functional roles of DNA interlacing in chromosomes, are briefly mentioned.

  13. Fabrication and testing of composite ring specimens

    Science.gov (United States)

    Liber, T.; Daniel, I. M.; Labedz, R.; Niiro, T.

    1979-01-01

    The tooling and techniques used in the fabrication of composite laminate tubes of any desired ply orientation and stacking sequence are described along with techniques for cutting ring specimens under internal pressure. The method consists of laying up the tube on a central circular mandrel, and by means of internal pressure, expanding the prepreg tube against the cavity wall of an external mold tool, which forms the geometric curing envelope for the tube. Tube quality is assessed by laminate wall thickness measurement, by hoop strength measurement on rings cut from the ends of the tube, and by ultrasonic inspection.

  14. Fundamental Plasmid Strings and Black Rings

    CERN Document Server

    Blanco-Pillado, Jose J; Iglesias, Alberto

    2008-01-01

    We construct excited states of fundamental strings that admit a semiclassical description as rotating circular loops of string. We identify them with the supergravity solutions for rotating dipole rings. The identification involves a precise match of the mass, radius and angular momentum of the two systems. Moreover, the degeneracy of the string state reproduces the parametric dependence of the entropy in the supergravity description. When the solutions possess two macroscopic angular momenta, they are better described as toroidal configurations (tubular loops) instead of loops of string. We argue that the decay of the string state can be interpreted as superradiant emission of quanta from the ergoregion of the rotating ring.

  15. Recent results of the ACO storage ring

    International Nuclear Information System (INIS)

    A permanent magnet undulator has been built and installed on the ACO Storage Ring. The undulator design, the spontaneous emission and gain of the system, as well as the laser induced bunch lengthening of the electron bunch, are presented. A low-loss optical cavity has been also recently built and operated on the ring. Its performance and the degradation problems of the mirrors are discussed. Amplification of the spontaneous emission stored in the optical cavity has been observed. Also, preliminary results on the operation of an optical klystron are reported and interpreted

  16. Roll ring assemblies for the Space Station

    Science.gov (United States)

    Batista, J.; Vise, J.; Young, K.

    1994-01-01

    Space Station Freedom requires the transmission of high power and signals through three different rotational interfaces. Roll ring technology was baselined by NASA for rotary joints to transfer up to 65.5 kW of power for 30 years at greater than 99 percent efficiency. Signal transfer requirements included MIL-STD-1553 data transmission and 4.5 MHz RS250A base and color video. A unique design for each rotary joint was developed and tested to accomplish power and signal transfer. An overview of roll ring technology is presented, followed by design requirements, hardware configuration, and test results.

  17. 拟Abel环%Quasi-Abel rings

    Institute of Scientific and Technical Information of China (English)

    范志勇; 魏俊潮; 李立斌

    2009-01-01

    Let R be a ring and M a R-bimodule. If eR(1- e)Me = eM(1- e)Re = 0 for every element e∈E E(R), then M is called quasi-Abel module, where E(R) is the set of all idempotent elements of R. If R as R-bimodule is quasi-Abel module, then R is called a quasi-Abel ring. This article proves some main results as follows: ① R is a quasi-Abel ring if and only if for any element a∈N(R), e∈ E(R), ea = 0 implies eRae=0; ② R is an Abel ring if and only if R is a nilpotent reflexive ring and quasi-Abel ring; (3) Suppose σ is an endomorphism of ring R such that σ(e) =e for any e ∈ E(R) , then R is a quasi-Abel ring if and only if R(σ) is quasi-Abel module.%设R是一个环,M是双R-模.若对每个e∈E(R),有eR(1-e)Me=eM(1-e)Re=0,则称M为拟Abel模,这里E(R)表示R的幂等元集合.若R-双模R是拟Abel的,则称R为拟Abel环.证明了如下结果:①R为拟Abel环当且仅当对任意的a∈N(R),e∈E(R),ea=0蕴涵eRae=0,这里N(R)表示R的幂零元集合;②R为Abel环当且仅当R为幂零自反环和拟Abel环;③设σ为环R的环自同态映射且满足条件: (A)e∈E(R),σ(e)=e,则R为拟Abel环当且仅当R(σ)为拟Abel模.

  18. Jittering waves in rings of pulse oscillators.

    Science.gov (United States)

    Klinshov, Vladimir; Shchapin, Dmitry; Yanchuk, Serhiy; Nekorkin, Vladimir

    2016-07-01

    Rings of oscillators with delayed pulse coupling are studied analytically, numerically, and experimentally. The basic regimes observed in such rings are rotating waves with constant interspike intervals and phase lags between the neighbors. We show that these rotating waves may destabilize leading to the so-called jittering waves. For these regimes, the interspike intervals are no more equal but form a periodic sequence in time. Analytic criterion for the emergence of jittering waves is derived and confirmed by the numerical and experimental data. The obtained results contribute to the hypothesis that the multijitter instability is universal in systems with pulse coupling. PMID:27575122

  19. J-regular rings with injectivities

    OpenAIRE

    Shen, Liang

    2010-01-01

    A ring $R$ is called a J-regular ring if R/J(R) is von Neumann regular, where J(R) is the Jacobson radical of R. It is proved that if R is J-regular, then (i) R is right n-injective if and only if every homomorphism from an $n$-generated small right ideal of $R$ to $R_{R}$ can be extended to one from $R_{R}$ to $R_{R}$; (ii) R is right FP-injective if and only if R is right (J, R)-FP-injective. Some known results are improved.

  20. Non-Linear Dynamics of Saturn's Rings

    Science.gov (United States)

    Esposito, L. W.

    2015-12-01

    Non-linear processes can explain why Saturn's rings are so active and dynamic. Some of this non-linearity is captured in a simple Predator-Prey Model: Periodic forcing from the moon causes streamline crowding; This damps the relative velocity, and allows aggregates to grow. About a quarter phase later, the aggregates stir the system to higher relative velocity and the limit cycle repeats each orbit, with relative velocity ranging from nearly zero to a multiple of the orbit average: 2-10x is possible. Summary of Halo Results: A predator-prey model for ring dynamics produces transient structures like 'straw' that can explain the halo structure and spectroscopy: Cyclic velocity changes cause perturbed regions to reach higher collision speeds at some orbital phases, which preferentially removes small regolith particles; Surrounding particles diffuse back too slowly to erase the effect: this gives the halo morphology; This requires energetic collisions (v ≈ 10m/sec, with throw distances about 200km, implying objects of scale R ≈ 20km); We propose 'straw', as observed ny Cassini cameras. Transform to Duffing Eqn : With the coordinate transformation, z = M2/3, the Predator-Prey equations can be combined to form a single second-order differential equation with harmonic resonance forcing. Ring dynamics and history implications: Moon-triggered clumping at perturbed regions in Saturn's rings creates both high velocity dispersion and large aggregates at these distances, explaining both small and large particles observed there. This confirms the triple architecture of ring particles: a broad size distribution of particles; these aggregate into temporary rubble piles; coated by a regolith of dust. We calculate the stationary size distribution using a cell-to-cell mapping procedure that converts the phase-plane trajectories to a Markov chain. Approximating the Markov chain as an asymmetric random walk with reflecting boundaries allows us to determine the power law index from

  1. Exotic statistics of leapfrogging vortex rings.

    Science.gov (United States)

    Niemi, Antti J

    2005-04-01

    The leapfrogging motion of vortex rings is a three-dimensional version of the motion that in two dimensions leads to exotic exchange statistics. The statistical phase factor can be computed using the hydrodynamical Euler equation, which suggests that three-dimensional exotic exchange statistics is a common property of vortex rings in a variety of quantum liquids and gases. Potential applications range from helium superfluids to Bose-Einstein condensed alkali gases, metallic hydrogen in its liquid phases, and maybe even nuclear matter in extreme conditions. PMID:15903923

  2. Cohomology of face rings, and torus actions

    OpenAIRE

    Panov, Taras

    2005-01-01

    In this survey article we present several new developments of `toric topology' concerning the cohomology of face rings (also known as Stanley-Reisner algebras). We prove that the integral cohomology algebra of the moment-angle complex Z_K (equivalently, of the complement U(K) of the coordinate subspace arrangement) determined by a simplicial complex K is isomorphic to the Tor-algebra of the face ring of K. Then we analyse Massey products and formality of this algebra by using a generalisation...

  3. Injection Control System of HLS Storage Ring

    CERN Document Server

    Liu, G; Li, W; Li Chuan; Li, K; Shang, L; Liu, Gongfa; Li, Jingyi; Li, Weimin; Li, Chuan; Li, Kaihong; Shang, Lei

    2001-01-01

    The injection control system of Hefei Light Source (HLS) storage ring is a subsystem of the upgraded HLS control system, which is based upon EPICS. Three programmable logic controllers (PLCs) are used as device controllers, which control one septum modulator and four kicker modulators of HLS storage ring. An Industrial PC is used as Input/Output Controller (IOC) and it connects the PLCs with serial communication (RS232 mode) over fibre. A PC with Linux is used as operator interface (OPI), operator application are running on it. The control system was completed in July 2000. The commissioning shows that the control system is reliable and easy operational.

  4. Jordan Higher Derivable Mappings on Rings

    Directory of Open Access Journals (Sweden)

    Mohammad Ashraf

    2014-01-01

    Full Text Available Let R be a ring. We say that a family of maps D={dn}n∈N is a Jordan higher derivable map (without assumption of additivity on R if d0=IR (the identity map on R and dn(ab+ba=∑p+q=n‍dp(adq(b+∑p+q=n‍dp(bdq(a hold for all a,b∈R and for each n∈N. In this paper, we show that every Jordan higher derivable map on a ring under certain assumptions becomes a higher derivation. As its application, we get that every Jordan higher derivable map on Banach algebra is an additive higher derivation.

  5. Technological Advancements

    Science.gov (United States)

    Kennedy, Mike

    2010-01-01

    The influx of technology has brought significant improvements to school facilities. Many of those advancements can be found in classrooms, but when students head down the hall to use the washrooms, they are likely to find a host of technological innovations that have improved conditions in that part of the building. This article describes modern…

  6. Advanced ferroelectricity

    CERN Document Server

    Blinc, R

    2011-01-01

    Advances in the field of ferroelectricity have implications both for basic physics and for technological applications such as memory devices, spintronic applications and electro-optic devices, as well as in acoustics, robotics, telecommunications and medicine. This book provides an account of recent developments in the field.

  7. Accidental ingestion of BiTine ring and a note on inefficient ring separation forceps

    Directory of Open Access Journals (Sweden)

    Baghele ON

    2011-05-01

    Full Text Available Om Nemichand Baghele1, Mangala Om Baghele21Department of Periodontology, SMBT Dental College and Hospital, Sangamner, Ahmednagar, Maharashtra, India; 2Private General Dental Practice, Mumbai, IndiaBackground: Accidental ingestion of medium-to-large instruments is relatively uncommon during dental treatment but can be potentially dangerous. A case of BiTine ring ingestion is presented with a note on inefficient ring separation forceps.Case description: A 28-year-old male patient accidentally ingested the BiTine ring (2 cm diameter, 0.5 cm outward projections while it was being applied to a distoproximal cavity in tooth # 19. The ring placement forceps were excessively flexible; bending of the beaks towards the ring combined with a poor no-slippage mechanism led to sudden disengagement of the ring and accelerated movement towards the pharynx. We followed the patient with bulk forming agents and radiographs. Fortunately the ring passed out without any complications.Clinical implications: Checking equipment and methods is as important as taking precautions against any preventable medical emergency. It is the responsibility of the clinician to check, verify and then use any instrument/equipment.Keywords: foreign bodies/radiography, foreign bodies/complications, equipment failure, dental instrument, accidental ingestion

  8. Recent Simulation Results on Ring Current Dynamics Using the Comprehensive Ring Current Model

    Science.gov (United States)

    Zheng, Yihua; Zaharia, Sorin G.; Lui, Anthony T. Y.; Fok, Mei-Ching

    2010-01-01

    Plasma sheet conditions and electromagnetic field configurations are both crucial in determining ring current evolution and connection to the ionosphere. In this presentation, we investigate how different conditions of plasma sheet distribution affect ring current properties. Results include comparative studies in 1) varying the radial distance of the plasma sheet boundary; 2) varying local time distribution of the source population; 3) varying the source spectra. Our results show that a source located farther away leads to a stronger ring current than a source that is closer to the Earth. Local time distribution of the source plays an important role in determining both the radial and azimuthal (local time) location of the ring current peak pressure. We found that post-midnight source locations generally lead to a stronger ring current. This finding is in agreement with Lavraud et al.. However, our results do not exhibit any simple dependence of the local time distribution of the peak ring current (within the lower energy range) on the local time distribution of the source, as suggested by Lavraud et al. [2008]. In addition, we will show how different specifications of the magnetic field in the simulation domain affect ring current dynamics in reference to the 20 November 2007 storm, which include initial results on coupling the CRCM with a three-dimensional (3-D) plasma force balance code to achieve self-consistency in the magnetic field.

  9. A new TL finger ring dosimetry system with automated ring identification

    International Nuclear Information System (INIS)

    TL finger ring dosemeters, particularly if used during surgery, etc., have to be small, convenient to wear and suitable for cold sterilisation. This makes automated ring identification difficult to achieve. A new approach is described, based on a circular TLD chip mounted with Kapton foil on a small aluminium disc containing a miniaturised circular bar code (radial 6 digit ITF) and a six digit number. The ring is inserted into a disposable plastic finger ring and protected by a circular cover plate. This ring design is convenient to wear, fits all finger sizes and can be cold sterilised for multiple use in surgery. For readout the ring is opened by a semi-automated device and up to four bar coded discs inserted into a modified standard TLD card for automatic processing by Harshaw readers models 6600 or 8800. The reader contains a video bar code identification system based on a minaturised CCD camera and image processing by special PC software. The circular bar codes are mathematically linearised and decoded directly from the enhanced grey scale picture obtained with optimised illumination by power LEDs. The system described (Patent No. A 398005/1994) is a fast and economic solution for fully (or semi-) automated evaluation of TLD finger rings in larger personnel monitoring services. (author)

  10. Overview of Advanced LIGO Adaptive Optics

    OpenAIRE

    Brooks, Aidan F.; Abbott, Benjamin; Arain, Muzammil A.; Ciani, Giacomo; Cole, Ayodele; Grabeel, Greg; Gustafson, Eric; Guido, Chris; Heintze, Matthew; Heptonstall, Alastair; Jacobson, Mindy; KIM, WON; King, Eleanor; Lynch, Alexander; O'Connor, Stephen

    2016-01-01

    This is an overview of the adaptive optics used in Advanced LIGO (aLIGO), known as the thermal compensation system (TCS). The thermal compensation system was designed to minimize thermally-induced spatial distortions in the interferometer optical modes and to provide some correction for static curvature errors in the core optics of aLIGO. The TCS is comprised of ring heater actuators, spatially tunable CO$_{2}$ laser projectors and Hartmann wavefront sensors. The system meets the requirements...

  11. Chariklo's ring system 1. Structure of the ring system from stellar occultations

    Science.gov (United States)

    Berard, Diane; Sicardy, Bruno; Braga-Ribas, Felipe; camargo, julio; Vieira-Martins, Roberto; Assafin, Marcelo; Sickafoose, Amanda A.; Colas, François; Dauvergne, Jean-Luc; Bath, Karl-Ludwig; Maquet, Lucie; Tancredi, Gonzalo; Richichi, Andrea; Puji, Irawati; Ivanov, Valentin; Bradshaw, Jonathan; Broughton, John; Meza, Erick; Ortiz, Jose-Luis; Duffard, Rene; Leiva, Rodrigo

    2016-10-01

    Two dense and narrow rings around Chariklo (the largest centaur object known to date) were discovered by stellar occultation on June 3, 2013 (Braga-Ribas et al., Nature 508, 72, 2014). The main and larger ring is called C1R, while the faintest one is called C2R.Here we report six others occultations by Chariklo's ring system observed on February 16, March 16, April 29, June 28, 2014 and April 26, May 12, 2015. They provide a total of fifteen ring profiles, among which are four resolved profiles of C1R.The latter exhibits a W-shape profile that is essentially opaque at the edges. Its width varies from 4.8 to 7.7 km over the available longitude range. Those caracteristics have been detected in Uranus elliptic rings. The equivalent width We (normal opacity x physical radial width) of C1R is 2 km with typical rms of 1 km, while C2R has We of 0.2 km (rms ~ 0.1 km). None of the rings exhibits variation of We with longitude.Assuming the rings are circular, we can exhibit a pole which is compatible with the two multi-chord ring detections (June 3, 2013 and April 29, 2014): αp=151.4° and δp=41.5°. We will then estimate an upper limit of a possible ring eccentricity based on those two observations.Part of the research leading to these results has received funding from the European Research Council under the European Community's H2020 (2014-2020/ ERC Grant Agreement n 669416 "LUCKY STAR").

  12. Modelling the progression of bird migration with conditional autoregressive models applied to ringing data.

    Directory of Open Access Journals (Sweden)

    Roberto Ambrosini

    Full Text Available Migration is a fundamental stage in the life history of several taxa, including birds, and is under strong selective pressure. At present, the only data that may allow for both an assessment of patterns of bird migration and for retrospective analyses of changes in migration timing are the databases of ring recoveries. We used ring recoveries of the Barn Swallow Hirundo rustica collected from 1908-2008 in Europe to model the calendar date at which a given proportion of birds is expected to have reached a given geographical area ('progression of migration' and to investigate the change in timing of migration over the same areas between three time periods (1908-1969, 1970-1990, 1991-2008. The analyses were conducted using binomial conditional autoregressive (CAR mixed models. We first concentrated on data from the British Isles and then expanded the models to western Europe and north Africa. We produced maps of the progression of migration that disclosed local patterns of migration consistent with those obtained from the analyses of the movements of ringed individuals. Timing of migration estimated from our model is consistent with data on migration phenology of the Barn Swallow available in the literature, but in some cases it is later than that estimated by data collected at ringing stations, which, however, may not be representative of migration phenology over large geographical areas. The comparison of median migration date estimated over the same geographical area among time periods showed no significant advancement of spring migration over the whole of Europe, but a significant advancement of autumn migration in southern Europe. Our modelling approach can be generalized to any records of ringing date and locality of individuals including those which have not been recovered subsequently, as well as to geo-referenced databases of sightings of migratory individuals.

  13. Kost - mad - næring

    DEFF Research Database (Denmark)

    Niklasson, Grit

    2010-01-01

    Kapitlet handler om kost og forskellige aspekter af menneskeføde og dens indtagelse. Mad- og måltidspolitik i institutionerne behandles, og ligeså næringsstofferne og deres betydning for kroppens sundhed, herunder også konsekvenserne af fejlernæring. Også allergi og intolerans over for fødeemner ...

  14. Bifurcation structure of an optical ring cavity

    DEFF Research Database (Denmark)

    Kubstrup, C.; Mosekilde, Erik

    1996-01-01

    One- and two-dimensional continuation techniques are applied to determine the basic bifurcation structure for an optical ring cavity with a nonlinear absorbing element (the Ikeda Map). By virtue of the periodic structure of the map, families of similar solutions develop in parameter space. Within...

  15. Krop, rum, læring

    DEFF Research Database (Denmark)

    Justiniano, Birgitte

    2009-01-01

    Ud fra afprøvning af forskellige somaæstetiske iscenesættelser i skolen beskæftiger artiklen sig med koblinger mellem kroppen, det fysiske rum, læring og sundhed. Jeg argumenterer for, at kombinationen af skolens kulturindhold, det faktuelle indhold i undervisningen samt det arkitektoniske og per...

  16. Guide til effektiv læring

    DEFF Research Database (Denmark)

    Elias, Stina Vrang; Holt Larsen, Henrik

    2011-01-01

    Hvordan bygger man bro mellem medarbejdernes individuelle kompetenceudvikling og hele virksomhedens læring og udvikling? Få indblik og inspiration i denne artikel om effektive læringsformer, der kan supplere de traditionelle kurser og uddannelser og gøre virksomhederne som helhed bedre til at lær...

  17. Miniaturized Planar Split-Ring Resonator Antenna

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav

    2009-01-01

    A miniaturized planar antenna based on a broadside-coupled split ring resonator excited by an arc-shaped dipole is presented. The excitation dipole acts as a small tuning capacitor in series with a parallel RLC circuit represented by the SRR. The antenna resonance frequency and dimensions...

  18. The Fluxgate Ring-Core Internal Field

    DEFF Research Database (Denmark)

    Primdahl, Fritz; Brauer, Peter; Merayo, José M.G.;

    2002-01-01

    A large number of measured demagnetizing factors for fluxgate ring cores of a wide range of cross section shapes have been compiled from the literature and plotted against the core cross-sectional area over the squared mean core diameter. The points group close to a straight line through the orig...

  19. Multi-ring-shaped optical field

    Science.gov (United States)

    Mei, Zhangrong; Zhao, Daomu; Gu, Juguan; Mao, Yonghua

    2016-04-01

    We introduce a novel class of planar random source producing far fields with multi-ring-shaped average intensity patterns by modeling the source degree of coherence, and confirm that such sources are physically genuine. Further, we derive the analytical expressions for the cross-spectral density (CSD) function of the beam-like fields generated by the novel source propagating in free space and in a linear isotropic random medium, and analyze the evolution of the spectral density and the state of coherence. It is shown that at some distance from the source the spectral density of the propagating beam in free space takes on the shape-invariant multi-ring profile, and the number of rings and intensity profiles of the beams can be flexibly adjusted by changing the source parameters. However, in atmospheric turbulence, we find that at sufficiently large distances from the source, the multi-ring profiles are destroyed by the medium, even if it remains such for intermediate distances from the source.

  20. Baltic Ring may soon become reality

    Index Scriptorium Estoniae

    2006-01-01

    Põhja-Euroopa energiasüsteemide ühendamiseks loodud projekti Baltic Ring raames kirjutasid Leedu ja Poola alla elektrivõrkude ühendamise lepingule. Välisminister Urmas Paet tõdeb, et Eesti on huvitatud Leedu tuumaenergia tulevikust

  1. Computerspil og læring

    Directory of Open Access Journals (Sweden)

    Lasse Juel Larsen

    2015-02-01

    Full Text Available Game-based learning og gamification er ord, der ofte optræder i forbindelse med computerspil og læring. Denne artikel vil analytisk undersøge, hvordan computerspil og læring går i forbindelse med hinanden. Artikel tager afsæt i Gregory Batesons læringsteori og læser denne igennem det kommercielle computerspil StarCraft 2 fra Blizzard Intertainment. Batesons læringsteori vil ikke alene blive gennemgået, men også udvidet og perspektiveret.  Formålet med denne indsats er at skabe et afsæt, der kan demonstrere, hvordan læring foregår i computerspil. Herefter vil afsættet blive anvendt til at destillere et læringsteoretisk udkast. Artiklen falder således i to dele, hvor den første analytisk adresserer, hvordan læring i computerspil foregår, mens den anden er teoriproducerende på baggrund af resultaterne fra første del.

  2. Low Energy Antiproton Ring experimental area

    CERN Multimedia

    1991-01-01

    The experimental area at the Low Energy Antiproton Ring (LEAR) is seen. This set up was used to slow down antiprotons which had been produced by colliding a proton beam with a solid target. The experiments in the hall then took antiprotons from LEAR to perform antimatter studies. One such experiment, PS210, produced the world's first antihydrogen atoms.

  3. Spillet om læring

    DEFF Research Database (Denmark)

    Hansen, Allan Dreyer; Bech, Stinne Lyager; Plum, Maja

    En analyse af Socialministeriet, Undervisningsministeriet, KL og BUPLs forsøg på at give udtrykket "læring i daginstitutioner" specifikt indhold. Analysen følger debatten op til udkast til lovforslag om "Pædagogiske læreplaner i dagtilbud". Udgangspunktet tages i Laclau og Mouffes diskursteori....

  4. The PHENIX ring imaging Cherenkov detector

    Energy Technology Data Exchange (ETDEWEB)

    Akiba, Y.; Begay, R.; Burwood-Hoy, J.; Chappell, R.B.; Crook, D.W.; Ebisu, K.; Emery, M.S.; Ferrierra, J.; Frawley, A.D.; Hamagaki, H.; Hara, H.; Hayano, R.S.; Hemmick, T.K.; Hibino, M.; Hutter, R.; Kennedy, M.; Kikuchi, J.; Matsumoto, T.; Moscone, G.G.; Nagasaka, Y.; Nishimura, S.; Oyama, K.; Sakaguchi, T.; Salomone, S.; Shigaki, K.; Tanaka, Y.; Walker, J.W.; Wintenberg, A.L.; Young, G.R

    2000-10-11

    The PHENIX experiment at RHIC is primarily a lepton and photon detector. Electron detection takes place in the two central arms of PHENIX, with the primary electron identifier in each arm being a ring imaging Cherenkov detector. This paper contains a description of the two identical RICH detectors and of their expected performance.

  5. Cell Biology: Cohesin Rings Leave Loose Ends

    Science.gov (United States)

    Skibbens, Robert V.

    2016-01-01

    Cohesins function in almost all aspects of chromosome biology. Two new studies confirm that a subset of cohesin subunits form a flexible but compressed ring that can be opened through degradation. X-ray crystallography supports potentially differing regulation of subunit associations. PMID:25649818

  6. Gorenstein Homological Dimensions and Change of Rings

    Institute of Scientific and Technical Information of China (English)

    Xiaoyan YANG

    2012-01-01

    In this paper,we shall be concerned with what happens of Gorenstein homological dimensions when certain modifications are made to a ring. The five structural operations addressed later are the formation of excellent extensions,localizations,Morita equivalences,polynomial extensions and power series extensions.

  7. Directional variance analysis of annual rings

    Science.gov (United States)

    Kumpulainen, P.; Marjanen, K.

    2010-07-01

    The wood quality measurement methods are of increasing importance in the wood industry. The goal is to produce more high quality products with higher marketing value than is produced today. One of the key factors for increasing the market value is to provide better measurements for increased information to support the decisions made later in the product chain. Strength and stiffness are important properties of the wood. They are related to mean annual ring width and its deviation. These indicators can be estimated from images taken from the log ends by two-dimensional power spectrum analysis. The spectrum analysis has been used successfully for images of pine. However, the annual rings in birch, for example are less distinguishable and the basic spectrum analysis method does not give reliable results. A novel method for local log end variance analysis based on Radon-transform is proposed. The directions and the positions of the annual rings can be estimated from local minimum and maximum variance estimates. Applying the spectrum analysis on the maximum local variance estimate instead of the original image produces more reliable estimate of the annual ring width. The proposed method is not limited to log end analysis only. It is usable in other two-dimensional random signal and texture analysis tasks.

  8. Orbital perturbations due to massive rings

    CERN Document Server

    Iorio, Lorenzo

    2012-01-01

    We analytically work out the long-term orbital perturbations induced by a homogeneous circular ring of radius Rr and mass mr on the motion of a test particle in the cases (I): r > R_r and (II): r < R_r. In order to extend the validity of our analysis to the orbital con?gurations of, e.g., some proposed spacecraftbased mission for fundamental physics like LISA and ASTROD, of possible annuli around the supermassive black hole in Sgr A* coming from tidal disruptions of incoming gas clouds, and to the e?ect of arti?cial space debris belts around the Earth, we do not restrict ourselves to the case in which the ring and the orbit of the perturbed particle lie just in the same plane. From the corrections to the standard secular perihelion precessions, recently determined by a team of astronomers for some planets of the Solar System, we infer upper bounds on mr for various putative and known annular matter distributions of natural origin (close circumsolar ring with R_r = 0.02-0.13 au, dust ring with R_r = 1 au, m...

  9. Delay-insensitive Multi-ring Structures

    DEFF Research Database (Denmark)

    Sparsø, Jens; Staunstrup, Jørgen

    1993-01-01

    into larger multi-ring structures. For this restricted class of structures, it becomes possible - even for circuits of realistic size and complexity - to analyze the performance and establish an understanding of the bottlenecks. The paper combines a number of previously published results and techniques...

  10. Ring Chromosome 7 in an Indian Woman

    Science.gov (United States)

    Kaur, Anupam; Dhillon, Sumit; Garg, P. D.; Singh, Jai Rup

    2008-01-01

    Background: Ring chromosome 7 [r(7)] is a rare cytogenetic aberration, with only 16 cases (including 3 females) reported in the literature to date. This is the first reported case of r(7) from India. Method: Clinical and cytogenetic investigations were carried out in an adult female with microcephaly and intellectual disability. Results: Ring…

  11. Girotondo dei Numeri (A Ring of Numbers).

    Science.gov (United States)

    Palandra, Maria; And Others

    This workbook in Italian for learning the numbers from one to ten is intended for use in a bilingual education setting. It is introduced and concluded by a song about playing "ring around the rosy" with numbers. Each paqe has a pen and ink drawing illustrating the number and a sentence about the picture and the number. (AMH)

  12. Hjerne og matematiklæring

    DEFF Research Database (Denmark)

    Ejersbo, Lisser Rye

    2009-01-01

    Sammenhænge mellem matematiklæring og hjernens funktioner i forhold til dels hjernens plasticitet, hjernens evne til at danne og huske mønstre samt hjernens evne til at automatisere de ting, vi lærer.   Udgivelsesdato: 15.06.09...

  13. Monopole-antimonopole and vortex rings

    Science.gov (United States)

    Teh, Rosy; Wong, Khai-Ming

    2005-08-01

    The SU(2) Yang-Mills-Higgs theory supports the existence of monopoles, antimonopoles, and vortex rings. In this paper, we would like to present new exact static antimonopole-monopole-antimonopole (A-M-A) configurations. The net magnetic charge of these configurations is always -1, while the net magnetic charge at the origin is always +1 for all positive integer values of the solution's parameter m. However, when m increases beyond 1, vortex rings appear coexisting with these AMA configurations. The number of vortex rings increases proportionally with the value of m. They are located in space where the Higgs field vanishes along rings. We also show that a single-point singularity in the Higgs field does not necessarily correspond to a structureless 1-monopole at the origin but to a zero-size monopole-antimonopole-monopole (MAM) structure when the solution's parameter m is odd. This monopole is the Wu-Yang-type monopole and it possesses the Dirac string potential in the Abelian gauge. These exact solutions are a different kind of Bogomol'nyi-Prasad-Sommerfield (BPS) solutions as they satisfy the first-order Bogomol'nyi equation but possess infinite energy due to a point singularity at the origin of the coordinate axes. They are all axially symmetrical about the z-axis.

  14. ring mod det ukendte

    DEFF Research Database (Denmark)

    Danneskiold-Samsøe, Ida

    2015-01-01

    Med titlen ”Learning for the unknown: A pragmatic analysis of learning in theater as temporary organizing” har jeg skrevet en artikel om, hvordan uafklarede situationer giver mulighed for læring i en kreativ organisation. Gennem en analyse af kommunikationen på en række ledelsesmøder på Aarhus...

  15. Electronic Aromaticity Index for Large Rings

    CERN Document Server

    Matito, Eduard

    2015-01-01

    We introduce a new electronic aromaticity index, AV1245, consisting in the average of the 4-center MCI values along the ring that keep a positional relationship of 1,2,4,5. AV1245 measures the extent of transferability of the delocalized electrons between bonds 1-2 and 4-5, which is expected to be large in conjugated circuits and, therefore, in aromatic molecules. A new algorithm for the calculation of MCI for large rings is also introduced and used to produce the data for the calibration of the new aromaticity index. AV1245 does not rely on reference values, does not suffer from large numerical precision errors, and it does not present any limitation on the nature of atoms, the molecular geometry or the level of calculation. It is a size-extensive measure with a small computational cost that grows linearly with the number of ring members. Therefore, it is specially suitable to study the aromaticity of large molecular rings as those occurring in belt-shaped M\\"obius structures or porphyrins.

  16. A Characterization of Projective-free Rings

    Institute of Scientific and Technical Information of China (English)

    P.M. Cohn

    2003-01-01

    A simple condition is given for a projective module to be free, in terms of the matrix presenting it. This leads to a criterion for a ring to be projective-free,and it provides a simple proof that Sylvester domains are projective-free.

  17. ring er ikke skolificering

    OpenAIRE

    Mehlsen, Camilla

    2008-01-01

    I mange vestlige lande er dagtilbud til de mindste børn ikke en del af uddannelsessystemet. Konsekvensen er, at meget læring går tabt, lyder det fra John Bennett, som står bag omfattende undersøgelser af OECD-landenes daginstitutioner.

  18. Synthesis of azaphenanthridines via anionic ring closure

    DEFF Research Database (Denmark)

    Hansen, Henriette Møller; Lysén, M.; Begtrup, M.;

    2005-01-01

    A new and convergent synthesis of azaphenanthridines via an anionic ring closure is reported. Ortho-lithiation/in situ borylation of cyanopyridines produces the corresponding cyanopyridylboronic esters, which undergo a Suzuki-Miyaura cross-coupling to give the key intermediates. Addition of lithi...

  19. Leg og læring

    DEFF Research Database (Denmark)

    Pedersen, Annette

    2008-01-01

    Leg synes at have et potentiale som metode til at fremme læring. Men hvordan? Legen har en vis grad af parallelitet med den virkelige verden i dens interaktive og relationelle strukturer. Det bliver muligt at finde nye meninger i interaktioner, som refererer til vante interaktionsformer, men alli...

  20. NGC 4340 Double Bar + Fossil Nuclear Ring

    CERN Document Server

    Erwin, P; Beckman, J E

    2000-01-01

    NGC 4340 is a double-barred SB0 galaxy in the Virgo cluster (Wozniak et al. 1995, A&AS 111, 115). Here, we show that this galaxy also posseses a luminous stellar nuclear ring of relatively old stars with little or no gas. The ring lies just outside the inner bar, at the probable inner inner Lindblad resonance (IILR) of the outer bar. Careful inspection of the isophotes and unsharp masks shows that the two bars are slightly misaligned, which suggests they may be independently rotating. The bright nuclear ring distorts the isophotes and ellipse fits and is most clearly seen in the unsharp mask (an inner bar also visible). B-R color maps show no features associated with the ring: it is the same color as the surrounding bulge, and thus probably an old, ``fossil'' remnant of an earlier star-formation episode. We use Simien & Prugniel's (1997, A&AS 126, 15) major-axis velocities to compute resonance curves; we use our spectrum along the outer-bar major axis to estimate that bar's pattern speed. The Omeg...

  1. Surface layer characterisation of bearing rings

    Directory of Open Access Journals (Sweden)

    S.J. Skrzypek

    2007-11-01

    Full Text Available austenite. Theoretical calculation of residual macro-stresses due to volume fraction of transformed austenite in bearing rings and following measurements of residual stresses were carried out as well. The bearing elements were made of 100Cr6 steel and they were smoothed and grinded.Design/methodology/approach: Particular features of diffraction patterns like angle position; shape and intensity are used to characterize phase composition, residual micro and macro-stresses, crystallographic texture, lattice parameter, defects density and crystalline size.Findings: Machining by micro-deformation causes microstructural changes i.e. mechanically induced phase transformation of retained austenite and residual macrostresses. E.g. grinding cased tension and small compression whereas the mechanical smoothing of bearing rings caused high compresive residual stresses about -713 MPa.Research limitations/implications: For precise interpretation of differences between following results needs another investigations: i.e. measurement of retained austenite and residual stresses in rings after heat treatment before any mechanical treatment.Practical implications: The non-destructive character and large number of structural informations contained in diffraction pattern are the beneficial feature of diffraction methods. Therefore they have potential ability in application to technological operations and to diagnostic during fatigue.Originality/value: The non-destructive structure characterisation of surface layers for various kinds of bearing rings can be powerful method in surface characterization and in quality control. This results contribute in general relations between microstructure and properties.

  2. Electron Storage Ring Development for ICS Sources

    Energy Technology Data Exchange (ETDEWEB)

    Loewen, Roderick [Lyncean Technologies, Inc., Palo Alto, CA (United States)

    2015-09-30

    There is an increasing world-wide interest in compact light sources based on Inverse Compton Scattering. Development of these types of light sources includes leveraging the investment in accelerator technology first developed at DOE National Laboratories. Although these types of light sources cannot replace the larger user-supported synchrotron facilities, they offer attractive alternatives for many x-ray science applications. Fundamental research at the SLAC National Laboratory in the 1990’s led to the idea of using laser-electron storage rings as a mechanism to generate x-rays with many properties of the larger synchrotron light facilities. This research led to a commercial spin-off of this technology. The SBIR project goal is to understand and improve the performance of the electron storage ring system of the commercially available Compact Light Source. The knowledge gained from studying a low-energy electron storage ring may also benefit other Inverse Compton Scattering (ICS) source development. Better electron storage ring performance is one of the key technologies necessary to extend the utility and breadth of applications of the CLS or related ICS sources. This grant includes a subcontract with SLAC for technical personnel and resources for modeling, feedback development, and related accelerator physics studies.

  3. Elevers læring og udvikling

    DEFF Research Database (Denmark)

    Skibsted, Else Bengaard; Løw, Ole

    Bogen giver lærerstuderende og lærere psykologisk indsigt i læreruddannelsens kompetenceområder 'Elevens læring og udvikling' & 'Specialpædagogik'. Bogen er skrevet af forskere og undervisere, der alle har en forskningsbaseret og empirisk tilgang til studiet af lærerarbejdet...

  4. Computations in intersection rings of flag bundles

    CERN Document Server

    Grayson, Daniel R; Stillman, Michael E

    2012-01-01

    Intersection rings of flag varieties and of isotropic flag varieties are generated by Chern classes of the tautological bundles modulo the relations coming from multiplicativity of total Chern classes. In this paper we describe the Groebner bases of the ideals of relations and give applications to computation of intersections, as implemented in Macaulay2.

  5. Ikt og læring

    DEFF Research Database (Denmark)

    Artiklerne i denne antologi er blevet til på baggrund af masterprojekter udarbejdet i forbindelse med afslutning af Masteruddannelsen i Ikt og læring (MIL). Ideen til antologien kom fra alumner, som fandt det relevant at sætte fokus på den iderigdom, kreativitet og nye viden, der skabes i...

  6. A first course in abstract algebra rings, groups, and fields

    CERN Document Server

    Anderson, Marlow

    2014-01-01

    Numbers, Polynomials, and Factoring The Natural Numbers The Integers Modular Arithmetic Polynomials with Rational CoefficientsFactorization of PolynomialsSection I in a NutshellRings, Domains, and Fields Rings Subrings and Unity Integral Domains and Fields Ideals Polynomials over a Field Section II in a NutshellRing Homomorphisms and Ideals Ring HomomorphismsThe Kernel Rings of Cosets The Isomorphism Theorem for Rings Maximal and Prime Ideals The Chinese Remainder Theorem Section III in a NutshellGroups Symmetries of Geometric Figures PermutationsAbstract Groups Subgroups Cyclic Groups Section

  7. On the azimuthal brightness variations of Saturn's rings

    Science.gov (United States)

    Franklin, F. A.; Colombo, G.

    1978-01-01

    A simple semiquantitative explanation is presented which accounts both for the presence of the azimuthal brightness variations in Saturn's ring A and for their absence in ring B. This explanation avoids any ad hoc reliance on albedo variations and/or synchronous rotation of ring particles. Instead, it requires only some degree of self-gravitation between nearby orbiting bodies. A bias in the particle distribution and corresponding photometric effects are thereby produced the latter corresponding very closely to the variations observed in ring A. Their absence in ring B is primarily a consequence of the higher optical thickness and decreasing importance of self-gravitation in that ring.

  8. Seminormality and local cohomology of toric face rings

    CERN Document Server

    Nguyen, Dang Hop

    2011-01-01

    We characterize toric face rings which are normal and seminormal. Extending results about local cohomology of W. Bruns, B. Ichim, P. Li and T. R\\"omer of seminormal monoid rings and Stanley toric face rings, we prove the vanishing of certain graded part of local cohomology of seminormal toric face rings. The combinatorial formula we obtain generalizes Hochster's formula. We also characterize all (necessarily seminormal) toric face rings which are $F$-pure or $F$-split over a field of characteristic $p>0$. An example is given to show that $F$-injectivity does not behave well with respect to face projections of toric face rings.

  9. Basin-ring spacing on the Moon, Mercury, and Mars

    Science.gov (United States)

    Pike, R.J.; Spudis, P.D.

    1987-01-01

    Radial spacing between concentric rings of impact basins that lack central peaks is statistically similar and nonrandom on the Moon, Mercury, and Mars, both inside and outside the main ring. One spacing interval, (2.0 ?? 0.3)0.5D, or an integer multiple of it, dominates most basin rings. Three analytical approaches yield similar results from 296 remapped or newly mapped rings of 67 multi-ringed basins: least-squares of rank-grouped rings, least-squares of rank and ring diameter for each basin, and averaged ratios of adjacent rings. Analysis of 106 rings of 53 two-ring basins by the first and third methods yields an integer multiple (2 ??) of 2.00.5D. There are two exceptions: (1) Rings adjacent to the main ring of multi-ring basins are consistently spaced at a slightly, but significantly, larger interval, (2.1 ?? 0.3)0.5D; (2) The 88 rings of 44 protobasins (large peak-plus-inner-ring craters) are spaced at an entirely different interval (3.3 ?? 0.6)0.5D. The statistically constant and target-invariant spacing of so many rings suggests that this characteristic may constrain formational models of impact basins on the terrestrial planets. The key elements of such a constraint include: (1) ring positions may not have been located by the same process(es) that formed ring topography; (2) ring location and emplacement of ring topography need not be coeval; (3) ring location, but not necessarily the mode of ring emplacement, reflects one process that operated at the time of impact; and (4) the process yields similarly-disposed topographic features that are spatially discrete at 20.5D intervals, or some multiple, rather than continuous. These four elements suggest that some type of wave mechanism dominates the location, but not necessarily the formation, of basin rings. The waves may be standing, rather than travelling. The ring topography itself may be emplaced at impact by this and/or other mechanisms and may reflect additional, including post-impact, influences. ?? 1987

  10. Feasibility analysis of two identity- based proxy ring signature schemes

    Institute of Scientific and Technical Information of China (English)

    Wang Huaqun; Zhang Lijun; Zhao Junxi

    2007-01-01

    Recently , proxy ring signature schemes have been shown to be useful in various applications , such as electronic polling, electronic payment, etc. Although many proxy ring signature schemes have been proposed, there are only two identity- based proxy ring signature schemes have been proposed until now, I.e., Cheng's scheme and Lang's scheme. It's unlucky that the two identity- based proxy ring signature schemes are unfeasible . This paper points out the reasons why the two identity- based proxy ring signature schemes are unfeasible. In order to design feasible and efficient identity-based proxy ring signature schemes from bilinear pairings , we have to search for other methods .

  11. Picard-Vessiot theory of differentially simple rings

    OpenAIRE

    Maurischat, Andreas

    2013-01-01

    In Picard-Vessiot theory, the Galois theory for linear differential equations, the Picard-Vessiot ring plays an important role, since it is the Picard-Vessiot ring which is a torsor (principal homogeneous space) for the Galois group (scheme). Like fields are simple rings having only (0) and (1) as ideals, the Picard-Vessiot ring is a differentially simple ring, i.e. a differential ring having only (0) and (1) as differential ideals. Having in mind that the classical Galois theory is a theory ...

  12. The Uranus Occultation of 10 June 1979. I. The Rings

    OpenAIRE

    Nicholson, P. D.; Matthews, K; Goldreich, P.

    1981-01-01

    Observations and analysis of a stellar occultation by the rings of Uranus on 10 June 1979 are presented. Occultations by rings 4, ɑ, β, y, δ, and є are identified, and radii and azimuths of the occulting segments in the plane of the rings calculated. Results for rings y and δ are consistent with the hypothesis (Elliot et al. 1978; Nicholson et ɑl. 1978) that these two rings are circular and coplanar, and an approximate upper limit of 8 X 10^(-5) is placed on the eccentricity of either ring...

  13. Chemical Sensors Based on Optical Ring Resonators

    Science.gov (United States)

    Homer, Margie; Manfreda, Allison; Mansour, Kamjou; Lin, Ying; Ksendzov, Alexander

    2005-01-01

    Chemical sensors based on optical ring resonators are undergoing development. A ring resonator according to this concept is a closed-circuit dielectric optical waveguide. The outermost layer of this waveguide, analogous to the optical cladding layer on an optical fiber, is a made of a polymer that (1) has an index of refraction lower than that of the waveguide core and (2) absorbs chemicals from the surrounding air. The index of refraction of the polymer changes with the concentration of absorbed chemical( s). The resonator is designed to operate with relatively strong evanescent-wave coupling between the outer polymer layer and the electromagnetic field propagating along the waveguide core. By virtue of this coupling, the chemically induced change in index of refraction of the polymer causes a measurable shift in the resonance peaks of the ring. In a prototype that has been used to demonstrate the feasibility of this sensor concept, the ring resonator is a dielectric optical waveguide laid out along a closed path resembling a racetrack (see Figure 1). The prototype was fabricated on a silicon substrate by use of standard techniques of thermal oxidation, chemical vapor deposition, photolithography, etching, and spin coating. The prototype resonator waveguide features an inner cladding of SiO2, a core of SixNy, and a chemical-sensing outer cladding of ethyl cellulose. In addition to the ring Chemical sensors based on optical ring resonators are undergoing development. A ring resonator according to this concept is a closed-circuit dielectric optical waveguide. The outermost layer of this waveguide, analogous to the optical cladding layer on an optical fiber, is a made of a polymer that (1) has an index of refraction lower than that of the waveguide core and (2) absorbs chemicals from the surrounding air. The index of refraction of the polymer changes with the concentration of absorbed chemical( s). The resonator is designed to operate with relatively strong

  14. Advanced Virgo

    CERN Multimedia

    Virgo, a first-generation interferometric gravitational wave (GW) detector, located in the European Gravitational Observatory, EGO, Cascina (Pisa-Italy) and constructed by the collaboration of French and Italian institutes (CNRS and INFN) has successfully completed its long-duration data taking runs. It is now undergoing a fundamental upgrade that exploits available cutting edges technology to open an exciting new window on the universe, with the first detection of a gravitational wave signal. Advanced Virgo (AdV) is the project to upgrade the Virgo detector to a second-generation instrument. AdV will be able to scan a volume of the Universe 1000 times larger than initial Virgo. AdV will be hosted in the same infrastructures as Virgo. The Advanced VIRGO project is funded and at present carried on by a larger collaboration of institutes belonging to CNRS- France , RMKI - Hungary, INFN- Italy, Nikhef - The Netherlands Polish Academy of Science - Poland.

  15. Advanced Photon Source research: Volume 1, Number 1, April 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-04-01

    The following articles are included in this publication: (1) The Advanced Photon Source: A Brief Overview; (2) MAD Analysis of FHIT at the Structural Biology Center; (3) Advances in High-Energy-Resolution X-ray Scattering at Beamline 3-ID; (4) X-ray Imaging and Microspectroscopy of the Mycorrhyizal Fungus-Plant Symbiosis; (5) Measurement and Control of Particle-beam Trajectories in the Advanced Photon Storage Ring; (6) Beam Acceleration and Storage at the Advanced Photon Source; and (7) Experimental Facilities Operations and Current Status.

  16. Advanced Photon Source research: Volume 1, Number 1, April 1998

    International Nuclear Information System (INIS)

    The following articles are included in this publication: (1) The Advanced Photon Source: A Brief Overview; (2) MAD Analysis of FHIT at the Structural Biology Center; (3) Advances in High-Energy-Resolution X-ray Scattering at Beamline 3-ID; (4) X-ray Imaging and Microspectroscopy of the Mycorrhyizal Fungus-Plant Symbiosis; (5) Measurement and Control of Particle-beam Trajectories in the Advanced Photon Storage Ring; (6) Beam Acceleration and Storage at the Advanced Photon Source; and (7) Experimental Facilities Operations and Current Status

  17. Generalized Semi-φ-Regular Rings%广义半π-正则环

    Institute of Scientific and Technical Information of China (English)

    严兴凤; 刘仲奎

    2009-01-01

    In this paper, the concept of right generalized semi-w-regular rings is defined. We prove that these rings are non-trival generalizations of both right GP-injective rings and semi- π-regular rings. Some properties of these rings are studied and some results about generalized semiregular rings and GP-injective rings are extended.

  18. Advanced Nanoemulsions

    Science.gov (United States)

    Fryd, Michael M.; Mason, Thomas G.

    2012-05-01

    Recent advances in the growing field of nanoemulsions are opening up new applications in many areas such as pharmaceuticals, foods, and cosmetics. Moreover, highly controlled nanoemulsions can also serve as excellent model systems for investigating basic scientific questions about soft matter. Here, we highlight some of the most recent developments in nanoemulsions, focusing on methods of formation, surface modification, material properties, and characterization. These developments provide insight into the substantial advantages that nanoemulsions can offer over their microscale emulsion counterparts.

  19. Advanced LIGO

    OpenAIRE

    Aasi, J.; Abbott, B.; Abbott, R.; Abbott, T.; Abernathy, M; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R.; Adya, V.; Affeldt, C.; Aggarwal, N.; Aguiar, O.; Ain, A.

    2014-01-01

    The Advanced LIGO gravitational wave detectors are second-generation instruments designed and built for the two LIGO observatories in Hanford, WA and Livingston, LA, USA. The two instruments are identical in design, and are specialized versions of a Michelson interferometer with 4 km long arms. As in Initial LIGO, Fabry–Perot cavities are used in the arms to increase the interaction time with a gravitational wave, and power recycling is used to increase the effective laser power. Signal recyc...

  20. Advanced Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Gordon R. [NETL

    2013-03-11

    The activity reported in this presentation is to provide the mechanical and physical property information needed to allow rational design, development and/or choice of alloys, manufacturing approaches, and environmental exposure and component life models to enable oxy-fuel combustion boilers to operate at Ultra-Supercritical (up to 650{degrees}C & between 22-30 MPa) and/or Advanced Ultra-Supercritical conditions (760{degrees}C & 35 MPa).