WorldWideScience

Sample records for spiral column configuration

  1. The handedness of historiated spiral columns.

    Science.gov (United States)

    Couzin, Robert

    2017-09-01

    Trajan's Column in Rome (AD 113) was the model for a modest number of other spiral columns decorated with figural, narrative imagery from antiquity to the present day. Most of these wind upwards to the right, often with a congruent spiral staircase within. A brief introductory consideration of antique screw direction in mechanical devices and fluted columns suggests that the former may have been affected by the handedness of designers and the latter by a preference for symmetry. However, for the historiated columns that are the main focus of this article, the determining factor was likely script direction. The manner in which this operated is considered, as well as competing mechanisms that might explain exceptions. A related phenomenon is the reversal of the spiral in a non-trivial number of reproductions of the antique columns, from Roman coinage to Renaissance and baroque drawings and engravings. Finally, the consistent inattention in academic literature to the spiral direction of historiated columns and the repeated publication of erroneous earlier reproductions warrants further consideration.

  2. Elimination of spiral waves and spatiotemporal chaos by the pulse with a specific spatiotemporal configuration

    International Nuclear Information System (INIS)

    Yuan Guoyong; Yang Shiping; Wang Guangrui; Chen Shigang

    2008-01-01

    Spiral waves and spatiotemporal chaos are sometimes harmful and should be controlled. In this paper spiral waves and spatiotemporal chaos are successfully eliminated by the pulse with a very specific spatiotemporal configuration. The excited position D of spiral waves or spatiotemporal chaos is first recorded at an arbitrary time (t 0 ). When the system at the domain D enters a recovering state, the external pulse is injected into the domain. If the intensity and the working time of the pulse are appropriate, spiral waves and spatiotemporal chaos can finally be eliminated because counter-directional waves can be generated by the pulse. There are two advantages in the method. One is that the tip can be quickly eliminated together with the body of spiral wave, and the other is that the injected pulse may be weak and the duration can be very short so that the original system is nearly not affected, which is important for practical applications

  3. Design of spiral fin type condenser for hydrogen cryogenic distillation column

    International Nuclear Information System (INIS)

    Iwai, Yasunori; Nishi, Masataka; Yamanishi, Toshihiko

    2005-08-01

    The purpose of this paper is the proposal of new concept condenser for hydrogen cryogenic distillation column of Hydrogen Isotope Separation System (ISS) in a fusion reactor, and the establishment of numerical evaluation method of the hydrogen isotope inventory in the condenser. A large amount of hydrogen isotopes including high concentration of tritium, radioactive hydrogen isotope, has been handled in the cryogenic distillation column. Therefore, from the safety point of view, cryogenic coolant tube was commonly arranged to surround the condensed area to prevent the mixing of tritium into the coolant. This inevitable arrangement leads the difficulty in the minimization of the condenser. The scale of condenser has influence on the scale of the ISS and its earthquake-resistance. The spiral fin type condenser, which introduces fins inside it and in coolant tube to enhance heat exchange, is proposed as a new concept condenser for hydrogen cryogenic distillation column to miniaturize the condenser. The volume of spiral fin type condenser is estimated to become less than half of that of coil tube type condenser currently in use. Accordingly, it is found that the adoption of spiral fin type condenser realizes the significant miniaturization of the ISS. Moreover, the numerical evaluation method of the hydrogen isotope inventory in the condenser is proposed. The validity of this method was confirmed by the experimental data. The synthetic design of the condenser for the hydrogen cryogenic distillation column is achieved by the combination of the proposed new concept condenser with the numerical evaluation method of the hydrogen isotope inventory. (author)

  4. The cat vertebral column: stance configuration and range of motion

    Science.gov (United States)

    Macpherson, J. M.; Ye, Y.; Peterson, B. W. (Principal Investigator)

    1998-01-01

    This study examined the configuration of the vertebral column of the cat during independent stance and in various flexed positions. The range of motion in the sagittal plane is similar across most thoracic and lumbar joints, with the exception of a lesser range at the transition region from thoracic-type to lumbar-type vertebrae. The upper thoracic column exhibits most of its range in dorsiflexion and the lower thoracic and lumbar in ventroflexion. Lateral flexion is limited to less than 5 degrees at all segments. The range in torsion is almost 180 degrees and occurs primarily in the midthoracic region, T4-T11. Contrary to the depiction in most atlases, the standing cat exhibits several curvatures, including a mild dorsiflexion in the lower lumbar segments, a marked ventroflexion in the lower thoracic and upper lumbar segments, and a profound dorsiflexion in the upper thoracic (above T9) and cervical segments. The curvatures are not significantly changed by altering stance distance but are affected by head posture. During stance, the top of the scapula lies well above the spines of the thoracic vertebrae, and the glenohumeral joint is just below the bodies of vertebrae T3-T5. Using a simple static model of the vertebral column in the sagittal plane, it was estimated that the bending moment due to gravity is bimodal with a dorsiflexion moment in the lower thoracic and lumbar region and a ventroflexion moment in the upper thoracic and cervical region. Given the bending moments and the position of the scapula during stance, it is proposed that two groups of scapular muscles provide the major antigravity support for the head and anterior trunk. Levator scapulae and serratus ventralis form the lateral group, inserting on the lateral processes of cervical vertebrae and on the ribs. The major and minor rhomboids form the medial group, inserting on the spinous tips of vertebrae from C4 to T4. It is also proposed that the hypaxial muscles, psoas major, minor, and quadratus

  5. Spiral Countercurrent Chromatography

    Science.gov (United States)

    Ito, Yoichiro; Knight, Martha; Finn, Thomas M.

    2013-01-01

    For many years, high-speed countercurrent chromatography conducted in open tubing coils has been widely used for the separation of natural and synthetic compounds. In this method, the retention of the stationary phase is solely provided by the Archimedean screw effect by rotating the coiled column in the centrifugal force field. However, the system fails to retain enough of the stationary phase for polar solvent systems such as the aqueous–aqueous polymer phase systems. To address this problem, the geometry of the coiled channel was modified to a spiral configuration so that the system could utilize the radially acting centrifugal force. This successfully improved the retention of the stationary phase. Two different types of spiral columns were fabricated: the spiral disk assembly, made by stacking multiple plastic disks with single or four interwoven spiral channels connected in series, and the spiral tube assembly, made by inserting the tetrafluoroethylene tubing into a spiral frame (spiral tube support). The capabilities of these column assemblies were successfully demonstrated by separations of peptides and proteins with polar two-phase solvent systems whose stationary phases had not been well retained in the earlier multilayer coil separation column for high-speed countercurrent chromatography. PMID:23833207

  6. Seismic Performance of RC Beam-Column Connections with Continuous Rectangular Spiral Transverse Reinforcements for Low Ductility Classes

    Directory of Open Access Journals (Sweden)

    Mohammadamin Azimi

    2014-01-01

    Full Text Available The seismic performance of RC columns could be significantly improved by continuous spiral reinforcement as a result of its adequate ductility and energy dissipation capacity. Due to post-earthquake brittle failure observations in beam-column connections, the seismic behaviour of such connections could greatly be improved by simultaneous application of this method in both beams and columns. In this study, a new proposed detail for beam to column connection introduced as “twisted opposing rectangular spiral” was experimentally and numerically investigated and its seismic performance was compared against normal rectangular spiral and conventional shear reinforcement systems. In this study, three full scale beam to column connections were first designed in conformance with Eurocode (EC2-04 for low ductility class connections and then tested by quasistatic cyclic loading recommended by ACI Building Code (ACI 318-02. Next, the experimental results were validated by numerical methods. Finally, the results revealed that the new proposed connection could improve the ultimate lateral resistance, ductility, and energy dissipation capacity.

  7. Input-Output Decoupling of a Distillation Column LV-Configuration

    DEFF Research Database (Denmark)

    Yazdi, H.; Jørgensen, Sten Bay; Bahar (fratrådt), Mehrdad

    1996-01-01

    Introduction, digraph approach, distillation column, digraph analysis, solution analysis, discussion and conclusion, references.......Introduction, digraph approach, distillation column, digraph analysis, solution analysis, discussion and conclusion, references....

  8. Partitioning and interfacial tracers for differentiating NAPL entrapment configuration: column-scale investigation.

    Science.gov (United States)

    Dai, D; Barranco, F T; Illangasekare, T H

    2001-12-15

    Research on the use of partitioning and interfacial tracers has led to the development of techniques for estimating subsurface NAPL amount and NAPL-water interfacial area. Although these techniques have been utilized with some success at field sites, current application is limited largely to NAPL at residual saturation, such as for the case of post-remediation settings where mobile NAPL has been removed through product recovery. The goal of this study was to fundamentally evaluate partitioning and interfacial tracer behavior in controlled column-scale test cells for a range of entrapment configurations varying in NAPL saturation, with the results serving as a determinant of technique efficacy (and design protocol) for use with complexly distributed NAPLs, possibly at high saturation, in heterogeneous aquifers. Representative end members of the range of entrapment configurations observed under conditions of natural heterogeneity (an occurrence with residual NAPL saturation [discontinuous blobs] and an occurrence with high NAPL saturation [continuous free-phase LNAPL lens]) were evaluated. Study results indicated accurate prediction (using measured tracer retardation and equilibrium-based computational techniques) of NAPL amount and NAPL-water interfacial area for the case of residual NAPL saturation. For the high-saturation LNAPL lens, results indicated that NAPL-water interfacial area, but not NAPL amount (underpredicted by 35%), can be reasonably determined using conventional computation techniques. Underprediction of NAPL amount lead to an erroneous prediction of NAPL distribution, as indicated by the NAPL morphology index. In light of these results, careful consideration should be given to technique design and critical assumptions before applying equilibrium-based partitioning tracer methodology to settings where NAPLs are complexly entrapped, such as in naturally heterogeneous subsurface formations.

  9. Investigating the Effect of Column Geometry on Separation Efficiency using 3D Printed Liquid Chromatographic Columns Containing Polymer Monolithic Phases.

    Science.gov (United States)

    Gupta, Vipul; Beirne, Stephen; Nesterenko, Pavel N; Paull, Brett

    2018-01-16

    Effect of column geometry on the liquid chromatographic separations using 3D printed liquid chromatographic columns with in-column polymerized monoliths has been studied. Three different liquid chromatographic columns were designed and 3D printed in titanium as 2D serpentine, 3D spiral, and 3D serpentine columns, of equal length and i.d. Successful in-column thermal polymerization of mechanically stable poly(BuMA-co-EDMA) monoliths was achieved within each design without any significant structural differences between phases. Van Deemter plots indicated higher efficiencies for the 3D serpentine chromatographic columns with higher aspect ratio turns at higher linear velocities and smaller analysis times as compared to their counterpart columns with lower aspect ratio turns. Computational fluid dynamic simulations of a basic monolithic structure indicated 44%, 90%, 100%, and 118% higher flow through narrow channels in the curved monolithic configuration as compared to the straight monolithic configuration at linear velocities of 1, 2.5, 5, and 10 mm s -1 , respectively. Isocratic RPLC separations with the 3D serpentine column resulted in an average 23% and 245% (8 solutes) increase in the number of theoretical plates as compared to the 3D spiral and 2D serpentine columns, respectively. Gradient RPLC separations with the 3D serpentine column resulted in an average 15% and 82% (8 solutes) increase in the peak capacity as compared to the 3D spiral and 2D serpentine columns, respectively. Use of the 3D serpentine column at a higher flow rate, as compared to the 3D spiral column, provided a 58% reduction in the analysis time and 74% increase in the peak capacity for the isocratic separations of the small molecules and the gradient separations of proteins, respectively.

  10. Biomechanical properties of orthogonal plate configuration versus parallel plate configuration using the same locking plate system for intra-articular distal humeral fractures under radial or ulnar column axial load.

    Science.gov (United States)

    Kudo, Toshiya; Hara, Akira; Iwase, Hideaki; Ichihara, Satoshi; Nagao, Masashi; Maruyama, Yuichiro; Kaneko, Kazuo

    2016-10-01

    Previous reports have questioned whether an orthogonal or parallel configuration is superior for distal humeral articular fractures. In previous clinical and biomechanical studies, implant failure of the posterolateral plate has been reported with orthogonal configurations; however, the reason for screw loosening in the posterolateral plate is unclear. The purpose of this study was to evaluate biomechanical properties and to clarify the causes of posterolateral plate loosening using a humeral fracture model under axial compression on the radial or ulnar column separately. And we changed only the plate set up: parallel or orthogonal. We used artificial bone to create an Association for the Study of Internal Fixation type 13-C2.3 intra-articular fracture model with a 1-cm supracondylar gap. We used an anatomically-preshaped distal humerus locking compression plate system (Synthes GmbH, Solothurn, Switzerland). Although this is originally an orthogonal plate system, we designed a mediolateral parallel configuration to use the contralateral medial plate instead of the posterolateral plate in the system. We calculated the stiffness of the radial and ulnar columns and anterior movement of the condylar fragment in the lateral view. The parallel configuration was superior to the orthogonal configuration regarding the stiffness of the radial column axial compression. There were significant differences between the two configurations regarding anterior movement of the capitellum during axial loading of the radial column. The posterolateral plate tended to bend anteriorly under axial compression compared with the medial or lateral plate. We believe that in the orthogonal configuration axial compression induced more anterior displacement of the capitellum than the trochlea, which eventually induced secondary fragment or screw dislocation on the posterolateral plate, or nonunion at the supracondylar level. In the parallel configuration, anterior movement of the capitellum or

  11. Logarithmic Spiral

    Indian Academy of Sciences (India)

    Switzerland) even today can see the. Archimedian spiral and the inscription under it on the tombstone of Jacob Bernoulli 1. Logarithmic Spiral in Nature. Apart from logarithmic spiral no other curve seems to have attracted the attention of scientists, ...

  12. High performing actuation system for use with a louver array for satellite thermal control. [design and performance tests on prototype Bourdon spiral configuration

    Science.gov (United States)

    Reusser, P. U.; Coebergh, J. A. F.

    1973-01-01

    A high performing actuation system has been developed to drive one pair or a set of 9 pairs of louver blades. The system uses a Bourdon spiral as the driving member. The response time of the liquid expansion of the spiral system is in the order of three seconds. Besides performance tests, qualification tests have been carried out on a prototype system, demonstrating that the actuation system withstands normal launching conditions; projected operating life of 7 years with more than 7000 cycles can be expected.

  13. Influence of the gas-liquid flow configuration in the absorption column on photosynthetic biogas upgrading in algal-bacterial photobioreactors.

    Science.gov (United States)

    Toledo-Cervantes, Alma; Madrid-Chirinos, Cindy; Cantera, Sara; Lebrero, Raquel; Muñoz, Raúl

    2017-02-01

    The potential of an algal-bacterial system consisting of a high rate algal pond (HRAP) interconnected to an absorption column (AC) via recirculation of the cultivation broth for the upgrading of biogas and digestate was investigated. The influence of the gas-liquid flow configuration in the AC on the photosynthetic biogas upgrading process was assessed. AC operation in a co-current configuration enabled to maintain a biomass productivity of 15gm -2 d -1 , while during counter-current operation biomass productivity decreased to 8.7±0.5gm -2 d -1 as a result of trace metal limitation. A bio-methane composition complying with most international regulatory limits for injection into natural gas grids was obtained regardless of the gas-liquid flow configuration. Furthermore, the influence of the recycling liquid to biogas flowrate (L/G) ratio on bio-methane quality was assessed under both operational configurations obtaining the best composition at an L/G ratio of 0.5 and co-current flow operation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Spiral symmetry

    CERN Document Server

    Hargittai, Istvan

    1992-01-01

    From the tiny twisted biological molecules to the gargantuan curling arms of many galaxies, the physical world contains a startling repetition of spiral patterns. Today, researchers have a keen interest in identifying, measuring, and defining these patterns in scientific terms. Spirals play an important role in the growth processes of many biological forms and organisms. Also, through time, humans have imitated spiral motifs in their art forms, and invented new and unusual spirals which have no counterparts in the natural world. Therefore, one goal of this multiauthored book is to stress the c

  15. Spiral-shaped disinfection reactors

    KAUST Repository

    Ghaffour, Noreddine

    2015-08-20

    This disclosure includes disinfection reactors and processes for the disinfection of water. Some disinfection reactors include a body that defines an inlet, an outlet, and a spiral flow path between the inlet and the outlet, in which the body is configured to receive water and a disinfectant at the inlet such that the water is exposed to the disinfectant as the water flows through the spiral flow path. Also disclosed are processes for disinfecting water in such disinfection reactors.

  16. Frequency spirals

    International Nuclear Information System (INIS)

    Ottino-Löffler, Bertrand; Strogatz, Steven H.

    2016-01-01

    We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “frequency spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, frequency spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

  17. Frequency spirals

    Energy Technology Data Exchange (ETDEWEB)

    Ottino-Löffler, Bertrand; Strogatz, Steven H., E-mail: strogatz@cornell.edu [Center for Applied Mathematics, Cornell University, Ithaca, New York 14853 (United States)

    2016-09-15

    We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “frequency spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, frequency spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

  18. Solvent extraction columns

    International Nuclear Information System (INIS)

    Middleton, P.; Smith, J.R.

    1979-01-01

    In pulsed columns for use in solvent extraction processes, e.g. the reprocessing of nuclear fuel, the horizontal perforated plates inside the column are separated by interplate spacers manufactured from metallic neutron absorbing material. The spacer may be in the form of a spiral or concentric circles separated by radial limbs, or may be of egg-box construction. Suitable neutron absorbing materials include stainless steel containing boron or gadolinium, hafnium metal or alloys of hafnium. (UK)

  19. Effect of bio-column composed of aged refuse on methane abatement--a novel configuration of biological oxidation in refuse landfill.

    Science.gov (United States)

    Han, Dan; Zhao, Youcai; Xue, Binjie; Chai, Xiaoli

    2010-01-01

    An experimental bio-column composed of aged refuse was installed around the exhaust pipe as a new way to mitigate methane in refuse landfill. One of the objectives of this work was to assess the effect of aged refuse thickness in bio-column on reducing CH4 emissions. Over the study period, methane oxidation was observed at various thicknesses, 5 cm (small size), 10 cm (middle size) and 15 cm (large size), representing one to three times of pipeline diameters. The middle and large size both showed over 90% methane conversion, and the highest methane conversion rate of above 95% occurred in the middle-size column cell. Michaelis-Menten equation addressed the methanotrophs diffusion in different layers of the bio-columns. Maximum methanotrophic activity (Vmax) measured at the three thicknesses ranged from 6.4 x 10(-3) to 15.6 x 10(-3) units, and the half-saturation value (K(M)) ranged from 0.85% to 1.67%. Both the highest Vmax and K(M) were observed at the middle-size of the bio-column, as well as the largest methanotrophs population, suggesting a significant efficiency of methane mitigation happened in the optimum zone with greatest affinity and methanotrophic bacteria activities. Therefore, bio-column is a potential style for methane abatement in landfill, and the aged refuse both naturally formed and artificially placed in the column plays a critical role in CH4 emission.

  20. Experimental comparison of standard fuel cells PEM in radial configuration, coil and spiral; Comparacion experimental de celdas de combustible tipo PEM en configuracion radial, serpentin y espiral

    Energy Technology Data Exchange (ETDEWEB)

    Cano Andrade, Sergio

    2008-12-15

    After analyzing each one of the possible energy sources to replace oil the following question arises: which of all the possible sources is the suitable one? With no doubt another important factor in the election of this source is due to take into account, which has to do with the great problem that the humanity deals on a daily basis: the greenhouse effect. Taking into account the greenhouse effect, the fuel cells on the basis of hydrogen are the more viable energy source to substitute oil, since in their operation they are friendly with the environment since they do not produce polluting agents, reducing enormously the problem of global heating in which the planet is bottled. It is very certain that many disadvantages in these fuel cells on the basis of hydrogen still exist, but the arduous investigations realized until the present time foresee an excellent future where the planet will be able to satisfy its daily energy demand on the basis of the hydrogen technology. In future works one must have special care of the humidity control of gases before entering the fuel cell, since it is an important parameter in the correct operation of the standard fuel cells PEM. In the present investigation the advance in the state-of-the-art of the hydrogen technology is illustrated, specifically with the generation of electricity on the basis of the novel configurations of standard fuel cells PEM. Until the moment similar work it has not been found in the bibliography similar work where it is experienced with this type of radial configuration for the hydrogen technologies. The geometry and the results presented/displayed in this analysis correspond to a work of the highest category in the state-of-the-art of the fuel cells; in addition, an ample expectation due to the highly satisfactory results found, either numerically as well as experimentally, in comparison with other geometries is obtained. [Spanish] Despues de analizar cada una de las posibles fuentes de energia para

  1. The spiral

    DEFF Research Database (Denmark)

    Bibace, Roger; Kharlamov, Nikita

    2013-01-01

    ’s work with Bernard Kaplan on symbol formation is a primer on this idea. This paper examines the idea of spirality and develops the notion of dynamic coexistence that can clarify the issue of directionality of development; that is, what is the general trajectory or ground plan that development assumes...... and the environment. The idea of dynamic coexistence is developed on this foundation. In the context of Werner and Kaplan’s work, dynamic coexistence represents the syncretic nature of processes and levels of organization: they are neither innately fused nor organized. Instead, the antithesis between fusion...

  2. Spiral tectonics

    Science.gov (United States)

    Hassan Asadiyan, Mohammad

    2014-05-01

    Spiral Tectonics (ST) is a new window to global tectonics introduced as alternative model for Plate Tectonics (PT). ST based upon Dahw(rolling) and Tahw(spreading) dynamics. Analogues to electric and magnetic components in the electromagnetic theory we could consider Dahw and Tahw as components of geodynamics, when one component increases the other decreases and vice versa. They are changed to each other during geological history. D-component represents continental crust and T-component represents oceanic crust. D and T are two arm of spiral-cell. T-arm 180 degree lags behind D-arm so named Retard-arm with respect to D or Forward-arm. It seems primary cell injected several billions years ago from Earth's center therefore the Earth's core was built up first then mantel and finally the crust was build up. Crust building initiate from Arabia (Mecca). As the universe extended gravitation wave swirled the earth fractaly along cycloid path from big to small scale. In global scale (order-0) ST collect continents in one side and abandoned Pacific Ocean in the other side. Recent researches also show two mantels upwelling in opposite side of the Earth: one under Africa (tectonic pose) and the other under Pacific Ocean (tectonic tail). In higher order (order-1) ST build up Africa in one side and S.America in the other side therefore left Atlantic Ocean meandered in between. In order-n e.g. Khoor Musa and Bandar-Deylam bay are seen meandered easterly in the Iranian part but Khoor Abdullah and Kuwait bay meandered westerly in the Arabian part, they are distributed symmetrically with respect to axis of Persian Gulf(PG), these two are fractal components of easterly Caspian-wing and westerly Black Sea-wing which split up from Anatoly. Caspian Sea and Black Sea make two legs of Y-like structure, this shape completely fitted with GPS-velocity map which start from PG and split up in the Catastrophic Point(Anatoly). We could consider PG as remnants of Ancient Ocean which spent up

  3. Small Column Ion Exchange

    International Nuclear Information System (INIS)

    Huff, Thomas

    2010-01-01

    Small Column Ion Exchange (SCIX) leverages a suite of technologies developed by DOE across the complex to achieve lifecycle savings. Technologies are applicable to multiple sites. Early testing supported multiple sites. Balance of SRS SCIX testing supports SRS deployment. A forma Systems Engineering Evaluation (SEE) was performed and selected Small Column Ion Exchange columns containing Crystalline Silicotitanate (CST) in a 2-column lead/lag configuration. SEE considered use of Spherical Resorcinol-Formaldehyde (sRF). Advantages of approach at SRS include: (1) no new buildings, (2) low volume of Cs waste in solid form compared to aqueous strip effluent; and availability of downstream processing facilities for immediate processing of spent resin.

  4. Observations of barred spirals

    International Nuclear Information System (INIS)

    Elmegreen, D.M.

    1990-01-01

    Observations of barred spiral galaxies are discussed which show that the presence of a bar increases the likelihood for grand design spiral structure only in early Hubble types. This result is contrary to the more common notion that grand design spiral structure generally accompanies bars in galaxies. Enhanced deprojected color images are shown which reveal that a secondary set of spiral arms commonly occurs in barred galaxies and also occasionally in ovally distorted galaxies. 6 refs

  5. Mechanical behavior of confined self-compacting reinforced concrete circular columns under concentric axial loading

    Directory of Open Access Journals (Sweden)

    Fouad Khairallah

    2013-12-01

    Full Text Available While there is abundant research information on ordinary confined concrete, there are little data on the behavior of Self-Compacting Concrete (SCC under such condition. Due to higher shrinkage and lower coarse aggregate content of SCC compared to that of Normal Concrete (NC, its composite performance under confined conditions needs more investigation. This paper has been devoted to investigate and compare the mechanical behavior of confined concrete circular columns cast with SCC and NC under concentric axial loading. The parameters affecting are including concrete compressive strength and confinement configuration. Twenty column specimens were casted and confined using four confinement techniques, CFRP wrap, FRP tube, GFRP wrap, and spiral steel hoops. The performance of the tested column specimens is evaluated based on mode of failure, load–displacement curve, stress–strain characteristics, ultimate strength, ductility, and degree of confinement.

  6. Considerations of an oscillating spiral universe cosmology

    International Nuclear Information System (INIS)

    Sachs, M.

    1989-01-01

    It is proposed that if the spiral configuration of galaxies is explicable in terms of the equations of motion of its constituent stars, as an expression of global laws of nature, then the universe as a whole may be similarly described in terms of the motions of its constituent galaxies with a similar spiral dynamics. With the functional form of the spiral paths in terms of Fresnel integrals, taken from solutions of equations in general relativity (from previous analyses of galactic configurations) the density of the universe at the big bang stage is determined. It is found to depend, numerically, on the neutron lifetime and the period of oscillation of the universe as a whole. There is some concluding discussion of the implications of this analysis of the matter of the universe at the big bang stage vis a vis the black hole state of matter

  7. Electromechanics of graphene spirals

    Energy Technology Data Exchange (ETDEWEB)

    Korhonen, Topi; Koskinen, Pekka, E-mail: pekka.koskinen@iki.fi [NanoScience Center, Department of Physics, University of Jyväskylä, 40014 Jyväskylä (Finland)

    2014-12-15

    Among the most fascinating nanostructure morphologies are spirals, hybrids of somewhat obscure topology and dimensionality with technologically attractive properties. Here, we investigate mechanical and electromechanical properties of graphene spirals upon elongation by using density-functional tight-binding, continuum elasticity theory, and classical force field molecular dynamics. It turns out that electronic properties are governed by interlayer interactions as opposed to strain effects. The structural behavior is governed by van der Waals interaction: in its absence spirals unfold with equidistant layer spacings, ripple formation at spiral perimeter, and steadily increasing axial force; in its presence, on the contrary, spirals unfold via smooth local peeling, complex geometries, and nearly constant axial force. These electromechanical trends ought to provide useful guidelines not only for additional theoretical investigations but also for forthcoming experiments on graphene spirals.

  8. Triangular spiral tilings

    International Nuclear Information System (INIS)

    Sushida, Takamichi; Hizume, Akio; Yamagishi, Yoshikazu

    2012-01-01

    The topology of spiral tilings is intimately related to phyllotaxis theory and continued fractions. A quadrilateral spiral tiling is determined by a suitable chosen triple (ζ, m, n), where ζ element of D/R, and m and n are relatively prime integers. We give a simple characterization when (ζ, m, n) produce a triangular spiral tiling. When m and n are fixed, the admissible generators ζ form a curve in the unit disk. The family of triangular spiral tilings with opposed parastichy pairs (m, n) is parameterized by the divergence angle arg (ζ), while triangular spiral tilings with non-opposed parastichy pairs are parameterized by the plastochrone ratio 1/|ζ|. The generators for triangular spiral tilings with opposed parastichy pairs are not dense in the complex parameter space, while those with non-opposed parastichy pairs are dense. The proofs will be given in a general setting of spiral multiple tilings. We present paper-folding (origami) sheets that build spiral towers whose top-down views are triangular tilings. (paper)

  9. Spirals on the sea

    Directory of Open Access Journals (Sweden)

    Walter Munk

    2001-12-01

    Full Text Available Spiral eddies were first seen in the sun glitter on the Apollo Mission 30 years ago; they have since been recorded on SAR missions and in the infrared. The spirals are globally distributed, 10-25 km in size and overwhelmingly cyclonic. They have not been explained. Under light winds favorable to visualization, linear surface features with high surfactant density and low surface roughness are of common occurrence. We have proposed that frontal formations concentrate the ambient shear and prevailing surfactants. Horizontal shear instabilities ensue when the shear becomes comparable to the coriolis frequency. The resulting vortices wind the liner features into spirals. The hypothesis needs to be tested by prolonged measurements and surface truth. Spiral eddies are a manifestation of a sub-mesoscale oceanography associated with upper ocean stirring; dimensional considerations suggest a horizontal diffusivity of order 103 m2 s-1.

  10. Spiral 2 Week

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    The main goal of this meeting is to present and discuss the current status of the Spiral-2 project at GANIL in front of a large community of scientists and engineers. Different issues have been tackled particularly the equipment around Spiral-2 like injectors, cryo-modules or beam diagnostics, a workshop was devoted to other facilities dedicated to radioactive ion beam production. This document gathers only the slides of the presentations.

  11. Stacking the Equiangular Spiral

    OpenAIRE

    Agrawal, A.; Azabi, Y. O.; Rahman, B. M.

    2013-01-01

    We present an algorithm that adapts the mature Stack and Draw (SaD) methodology for fabricating the exotic Equiangular Spiral Photonic Crystal Fiber. (ES-PCF) The principle of Steiner chains and circle packing is exploited to obtain a non-hexagonal design using a stacking procedure based on Hexagonal Close Packing. The optical properties of the proposed structure are promising for SuperContinuum Generation. This approach could make accessible not only the equiangular spiral but also other qua...

  12. Spiral 2 Week

    International Nuclear Information System (INIS)

    2007-01-01

    The main goal of this meeting is to present and discuss the current status of the Spiral-2 project at GANIL in front of a large community of scientists and engineers. Different issues have been tackled particularly the equipment around Spiral-2 like injectors, cryo-modules or beam diagnostics, a workshop was devoted to other facilities dedicated to radioactive ion beam production. This document gathers only the slides of the presentations

  13. High-Assurance Spiral

    Science.gov (United States)

    2017-11-01

    HIGH-ASSURANCE SPIRAL CARNEGIE MELLON UNIVERSITY NOVEMBER 2017 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED STINFO...MU 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Carnegie Mellon University 5000 Forbes Ave Pittsburgh, PA 15217 8. PERFORMING ORGANIZATION...Approved for Public Release; Distribution Unlimited. Carnegie Mellon Carnegie Mellon HA SPIRAL Code Synthesis KeYmaera X Hybrid Theorem Prover

  14. High assurance SPIRAL

    Science.gov (United States)

    Franchetti, Franz; Sandryhaila, Aliaksei; Johnson, Jeremy R.

    2014-06-01

    In this paper we introduce High Assurance SPIRAL to solve the last mile problem for the synthesis of high assurance implementations of controllers for vehicular systems that are executed in today's and future embedded and high performance embedded system processors. High Assurance SPIRAL is a scalable methodology to translate a high level specification of a high assurance controller into a highly resource-efficient, platform-adapted, verified control software implementation for a given platform in a language like C or C++. High Assurance SPIRAL proves that the implementation is equivalent to the specification written in the control engineer's domain language. Our approach scales to problems involving floating-point calculations and provides highly optimized synthesized code. It is possible to estimate the available headroom to enable assurance/performance trade-offs under real-time constraints, and enables the synthesis of multiple implementation variants to make attacks harder. At the core of High Assurance SPIRAL is the Hybrid Control Operator Language (HCOL) that leverages advanced mathematical constructs expressing the controller specification to provide high quality translation capabilities. Combined with a verified/certified compiler, High Assurance SPIRAL provides a comprehensive complete solution to the efficient synthesis of verifiable high assurance controllers. We demonstrate High Assurance SPIRALs capability by co-synthesizing proofs and implementations for attack detection and sensor spoofing algorithms and deploy the code as ROS nodes on the Landshark unmanned ground vehicle and on a Synthetic Car in a real-time simulator.

  15. Spiral silicon drift detectors

    International Nuclear Information System (INIS)

    Rehak, P.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Lutz, G.; Kemmer, J.; Prechtel, U.; Ziemann, T.

    1988-01-01

    An advanced large area silicon photodiode (and x-ray detector), called Spiral Drift Detector, was designed, produced and tested. The Spiral Detector belongs to the family of silicon drift detectors and is an improvement of the well known Cylindrical Drift Detector. In both detectors, signal electrons created in silicon by fast charged particles or photons are drifting toward a practically point-like collection anode. The capacitance of the anode is therefore kept at the minimum (0.1pF). The concentric rings of the cylindrical detector are replaced by a continuous spiral in the new detector. The spiral geometry detector design leads to a decrease of the detector leakage current. In the spiral detector all electrons generated at the silicon-silicon oxide interface are collected on a guard sink rather than contributing to the detector leakage current. The decrease of the leakage current reduces the parallel noise of the detector. This decrease of the leakage current and the very small capacities of the detector anode with a capacitively matched preamplifier may improve the energy resolution of Spiral Drift Detectors operating at room temperature down to about 50 electrons rms. This resolution is in the range attainable at present only by cooled semiconductor detectors. 5 refs., 10 figs

  16. New developments in the theory of spiral galaxies

    International Nuclear Information System (INIS)

    Thielheim, K.O.

    1982-01-01

    About 30% of all galaxies exhibit spiral forms, 60% are elliptical and 10% irregular. It is the objective of galactic dynamics to explain these structural features. A first generation of self-consistent N-body simulations indicates that ellipticals are equilibrium configurations of gravitationally interacting multi-particle systems for which unfortunately a theory does not yet exist. Recent progress has been made on the modal analysis of Freeman disks. In a second generation of N-body simulations spiral density waves have been reproduced in disk configurations. As an alternative to the Lin-Shu conjecture based on the QSSS-hypothesis the author considers a mechanism by which spiral density waves are produced in the surrounding disk as a consequence of the slow increase of the quadrupole moment of a central oval shaped equilibrium configuration immersed in the disk. (Auth.)

  17. Plasma Generator Using Spiral Conductors

    Science.gov (United States)

    Szatkowski, George N. (Inventor); Dudley, Kenneth L. (Inventor); Ticatch, Larry A. (Inventor); Smith, Laura J. (Inventor); Koppen, Sandra V. (Inventor); Nguyen, Truong X. (Inventor); Ely, Jay J. (Inventor)

    2016-01-01

    A plasma generator includes a pair of identical spiraled electrical conductors separated by dielectric material. Both spiraled conductors have inductance and capacitance wherein, in the presence of a time-varying electromagnetic field, the spiraled conductors resonate to generate a harmonic electromagnetic field response. The spiraled conductors lie in parallel planes and partially overlap one another in a direction perpendicular to the parallel planes. The geometric centers of the spiraled conductors define endpoints of a line that is non-perpendicular with respect to the parallel planes. A voltage source coupled across the spiraled conductors applies a voltage sufficient to generate a plasma in at least a portion of the dielectric material.

  18. Barred spiral structure of galaxies

    International Nuclear Information System (INIS)

    Chen, Z.; Weng, s.; Xu, M.

    1982-01-01

    Observational data indicate the grand design of spiral or barred spiral structure in disk galaxies. The problem of spiral structure has been thoroughly investigated by C. C. Lin and his collaborators, but yet the problem of barred spiral structure has not been investigated systematically, although much work has been done, such as in Ref. 3--7. Using the gasdynamic model for galaxies and a method of integral transform presented in Ref. 1, we investigated the barred spiral structure and obtained an analytical solution. It gives the large-scale pattern of barred-spirals, which is in fairly good agreement with observational data

  19. Investigation of Spiral and Sweeping Holes

    Science.gov (United States)

    Thurman, Douglas; Poinsatte, Philip; Ameri, Ali; Culley, Dennis; Raghu, Surya; Shyam, Vikram

    2015-01-01

    Surface infrared thermography, hotwire anemometry, and thermocouple surveys were performed on two new film cooling hole geometries: spiral/rifled holes and fluidic sweeping holes. The spiral holes attempt to induce large-scale vorticity to the film cooling jet as it exits the hole to prevent the formation of the kidney shaped vortices commonly associated with film cooling jets. The fluidic sweeping hole uses a passive in-hole geometry to induce jet sweeping at frequencies that scale with blowing ratios. The spiral hole performance is compared to that of round holes with and without compound angles. The fluidic hole is of the diffusion class of holes and is therefore compared to a 777 hole and Square holes. A patent-pending spiral hole design showed the highest potential of the non-diffusion type hole configurations. Velocity contours and flow temperature were acquired at discreet cross-sections of the downstream flow field. The passive fluidic sweeping hole shows the most uniform cooling distribution but suffers from low span-averaged effectiveness levels due to enhanced mixing. The data was taken at a Reynolds number of 11,000 based on hole diameter and freestream velocity. Infrared thermography was taken for blowing rations of 1.0, 1.5, 2.0, and 2.5 at a density ration of 1.05. The flow inside the fluidic sweeping hole was studied using 3D unsteady RANS.

  20. Chiral Magnetic Spirals

    International Nuclear Information System (INIS)

    Basar, Goekce; Dunne, Gerald V.; Kharzeev, Dmitri E.

    2010-01-01

    We argue that the presence of a very strong magnetic field in the chirally broken phase induces inhomogeneous expectation values, of a spiral nature along the magnetic field axis, for the currents of charge and chirality, when there is finite baryon density or an imbalance between left and right chiralities. This 'chiral magnetic spiral' is a gapless excitation transporting the currents of (i) charge (at finite chirality), and (ii) chirality (at finite baryon density) along the direction of the magnetic field. In both cases it also induces in the transverse directions oscillating currents of charge and chirality. In heavy ion collisions, the chiral magnetic spiral possibly provides contributions both to the out-of-plane and the in-plane dynamical charge fluctuations recently observed at BNL RHIC.

  1. The Spiral of Euroscepticism

    DEFF Research Database (Denmark)

    Galpin, Charlotte; Trenz, Hans-Jörg

    2017-01-01

    of Euroscepticism’, taking media autonomy seriously to understand how media logics and selective devices contribute to the shaping of public discourse about the EU. We review the literature on the media and EU legitimacy to show how media frames and their amplification on social media can account for the salience......Media scholars have increasingly examined the effects of a negativity bias that applies to political news. In the ‘spiral of cynicism’, journalist preferences for negative news correspond to public demands for sensational news. We argue that this spiral of cynicism in EU news results in a ‘spiral...... of Eurosceptic opinions in the public sphere that then push parties to contest the EU in predominantly negative terms....

  2. Embracing the Spiral

    Directory of Open Access Journals (Sweden)

    Li Mao

    2016-12-01

    Full Text Available Critical research demands that we interrogate our own positionality and social location. Critical reflexivity is a form of researcher critical consciousness that is constant and dynamic in a complex spiral-like process starting within our own experiences as racialized, gendered, and classed beings embedded in particular sociopolitical contexts. Across diverse critical methodologies, a group of graduate students and their supervisor explored their own conceptualization of the reflexivity spiral by reflecting on how their research motivations and methodologies emerged from their racializing, colonizing, language-learning, parenting, and identity negotiating experiences. In this article, they present a spiral model of the critical reflexivity process, review the literature on reflexivity, and conclude with a description of critical reflexivity as a social practice within a supportive and collaborative graduate school experience.

  3. PULSE COLUMN

    Science.gov (United States)

    Grimmett, E.S.

    1964-01-01

    This patent covers a continuous countercurrent liquidsolids contactor column having a number of contactor states each comprising a perforated plate, a layer of balls, and a downcomer tube; a liquid-pulsing piston; and a solids discharger formed of a conical section at the bottom of the column, and a tubular extension on the lowest downcomer terminating in the conical section. Between the conical section and the downcomer extension is formed a small annular opening, through which solids fall coming through the perforated plate of the lowest contactor stage. This annular opening is small enough that the pressure drop thereacross is greater than the pressure drop upward through the lowest contactor stage. (AEC)

  4. The spinning ball spiral

    International Nuclear Information System (INIS)

    Dupeux, Guillaume; Le Goff, Anne; Quere, David; Clanet, Christophe

    2010-01-01

    We discuss the trajectory of a fast revolving solid ball moving in a fluid of comparable density. As the ball slows down owing to drag, its trajectory follows an exponential spiral as long as the rotation speed remains constant: at the characteristic distance L where the ball speed is significantly affected by the drag, the bending of the trajectory increases, surprisingly. Later, the rotation speed decreases, which makes the ball follow a second kind of spiral, also described in the paper. Finally, the use of these highly curved trajectories is shown to be relevant to sports.

  5. Are spiral galaxies heavy smokers?

    International Nuclear Information System (INIS)

    Davies, J.; Disney, M.; Phillipps, S

    1990-01-01

    The dustiness of spiral galaxies is discussed. Starburst galaxies and the shortage of truly bright spiral galaxies is cited as evidence that spiral galaxies are far dustier than has been thought. The possibility is considered that the dust may be hiding missing mass

  6. Properties of spiral resonators

    International Nuclear Information System (INIS)

    Haeuser, J.

    1989-10-01

    The present thesis deals with the calculation and the study of the application possibilities of single and double spiral resonators. The main aim was the development and the construction of reliable and effective high-power spiral resonators for the UNILAC of the GSI in Darmstadt and the H - -injector for the storage ring HERA of DESY in Hamburg. After the presentation of the construction and the properties of spiral resonators and their description by oscillating-circuit models the theoretical foundations of the bunching are presented and some examples of a rebuncher and debuncher and their influence on the longitudinal particle dynamics are shown. After the description of the characteristic accelerator quantities by means of an oscillating-circuit model and the theory of an inhomogeneous λ/4 line it is shown, how the resonance frequency and the efficiency of single and double spiral resonators can be calculated from the geometrical quantities of the structure. In the following the dependence of the maximal reachable resonator voltage in dependence on the gap width and the surface of the drift tubes is studied. Furthermore the high-power resonators are presented, which were built for the different applications for the GSI in Darmstadt, DESY in Hamburg, and for the FOM Institute in Amsterdam. (orig./HSI) [de

  7. Tracking Target and Spiral Waves

    DEFF Research Database (Denmark)

    Jensen, Flemming G.; Sporring, Jon; Nielsen, Mads

    2002-01-01

    A new algorithm for analyzing the evolution of patterns of spiral and target waves in large aspect ratio chemical systems is introduced. The algorithm does not depend on finding the spiral tip but locates the center of the pattern by a new concept, called the spiral focus, which is defined...... by the evolutes of the actual spiral or target wave. With the use of Gaussian smoothing, a robust method is developed that permits the identification of targets and spirals foci independently of the wave profile. Examples of an analysis of long image sequences from experiments with the Belousov......–Zhabotinsky reaction catalyzed by ruthenium-tris-bipyridyl are presented. Moving target and spiral foci are found, and the speed and direction of movement of single as well as double spiral foci are investigated. For the experiments analyzed in this paper it is found that the movement of a focus correlates with foci...

  8. Forming Spirals From Shadows

    Science.gov (United States)

    Kohler, Susanna

    2016-07-01

    What causes the large-scale spiral structures found in some protoplanetary disks? Most models assume theyre created by newly-forming planets, but a new study suggests that planets might have nothing to do with it.Perturbations from Planets?In some transition disks protoplanetary disks with gaps in their inner regions weve directly imaged large-scale spiral arms. Many theories currently attribute the formation of these structures to young planets: either the direct perturbations of a planet embedded in the disk cause the spirals, or theyre indirectly caused by the orbit of a planetary body outside of the arms.Another example of spiral arms detected in a protoplanetary disk, MWC 758. [NASA/ESA/ESO/M. Benisty et al.]But what if you could get spirals without any planets? A team of scientists led by Matas Montesinos (University of Chile) have recently published a study in which they examine what happens to a shadowed protoplanetary disk.Casting Shadows with WarpsIn the teams setup, they envision a protoplanetary disk that is warped: the inner region is slightly tilted relative to the outer region. As the central star casts light out over its protoplanetary disk, this disk warping would cause some regions of the disk to be shaded in a way that isnt axially symmetric with potentially interesting implications.Montesinos and collaborators ran 2D hydrodynamics simulations to determine what happens to the motion of particles within the disk when they pass in and out of the shadowed regions. Since the shadowed regions are significantly colder than the illuminated disk, the pressure in these regions is much lower. Particles are therefore accelerated and decelerated as they pass through these regions, and the lack of axial symmetry causes spiral density waves to form in the disk as a result.Initial profile for the stellar heating rate per unit area for one of the authors simulations. The regions shadowed as a result of the disk warp subtend 0.5 radians each (shown on the left

  9. Theory of spiral structure

    International Nuclear Information System (INIS)

    Lin, C.C.

    1977-01-01

    The density wave theory of galactic spirals has now developed into a form suitable for consideration by experts in Applied Mechanics. On the one hand, comparison of theoretical deductions with observational data has convinced astrophysicists of the validity of the basic physical picture and the calculated results. On the other hand, the dynamical problems of a stellar system, such as those concerning the origin of spiral structure in galaxies, have not been completely solved. This paper reviews the current status of such developments, including a brief summary of comparison with observations. A particularly important mechanism, currently called the mechanism of energy exchange, is described in some detail. The mathematical problems and the physical processes involved are similar to those occurring in certain instability mechanisms in the 'magnetic bottle' designed for plasma containment. Speculations are given on the future developments of the theory and on observational programs. (Auth.)

  10. Spiral 2 workshop

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The accelerator and experimental facilities at GANIL will be transformed over the next 5-10 years. The centerpiece of the additions to the accelerator complex will be Spiral-2. This is the first phase of a new radioactive beam facility based on the ISOL principle. The main aim of Spiral-2 will be to produce intense, high quality beams of neutron-rich nuclei created in neutron-induced fission of heavy elements and accelerated by the existing CIME cyclotron. The principal aims of this workshop will be a) to publicize the new facilities, b) to discuss and define the science which might be carried out with them, c) to discuss the instrumentation and infrastructure required to exploit the new facilities and d) to help form collaborations of scientists wishing to design and construct the equipment needed to undertake the science programme. This document gathers most of the slides presented in the workshop.

  11. Spiral nonimaging optical designs

    Science.gov (United States)

    Zamora, Pablo; Benítez, Pablo; Miñano, Juan C.; Vilaplana, Juan

    2011-10-01

    Manufacturing technologies as injection molding or embossing specify their production limits for minimum radii of the vertices or draft angle for demolding, for instance. In some demanding nonimaging applications, these restrictions may limit the system optical efficiency or affect the generation of undesired artifacts on the illumination pattern. A novel manufacturing concept is presented here, in which the optical surfaces are not obtained from the usual revolution symmetry with respect to a central axis (z axis), but they are calculated as free-form surfaces describing a spiral trajectory around z axis. The main advantage of this new concept lies in the manufacturing process: a molded piece can be easily separated from its mold just by applying a combination of rotational movement around axis z and linear movement along axis z, even for negative draft angles. Some of these spiral symmetry examples will be shown here, as well as their simulated results.

  12. Spiral 2 workshop

    International Nuclear Information System (INIS)

    2004-01-01

    The accelerator and experimental facilities at GANIL will be transformed over the next 5-10 years. The centerpiece of the additions to the accelerator complex will be Spiral-2. This is the first phase of a new radioactive beam facility based on the ISOL principle. The main aim of Spiral-2 will be to produce intense, high quality beams of neutron-rich nuclei created in neutron-induced fission of heavy elements and accelerated by the existing CIME cyclotron. The principal aims of this workshop will be a) to publicize the new facilities, b) to discuss and define the science which might be carried out with them, c) to discuss the instrumentation and infrastructure required to exploit the new facilities and d) to help form collaborations of scientists wishing to design and construct the equipment needed to undertake the science programme. This document gathers most of the slides presented in the workshop

  13. Holographic Chiral Magnetic Spiral

    International Nuclear Information System (INIS)

    Kim, Keun-Young; Sahoo, Bindusar; Yee, Ho-Ung

    2010-06-01

    We study the ground state of baryonic/axial matter at zero temperature chiral-symmetry broken phase under a large magnetic field, in the framework of holographic QCD by Sakai-Sugimoto. Our study is motivated by a recent proposal of chiral magnetic spiral phase that has been argued to be favored against previously studied phase of homogeneous distribution of axial/baryonic currents in terms of meson super-currents dictated by triangle anomalies in QCD. Our results provide an existence proof of chiral magnetic spiral in strong coupling regime via holography, at least for large axial chemical potentials, whereas we don't find the phenomenon in the case of purely baryonic chemical potential. (author)

  14. SPIRAL2/DESIR high resolution mass separator

    Energy Technology Data Exchange (ETDEWEB)

    Kurtukian-Nieto, T., E-mail: kurtukia@cenbg.in2p3.fr [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Baartman, R. [TRIUMF, 4004 Wesbrook Mall, Vancouver B.C., V6T 2A3 (Canada); Blank, B.; Chiron, T. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Davids, C. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Delalee, F. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Duval, M. [GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); El Abbeir, S.; Fournier, A. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Lunney, D. [CSNSM-IN2P3-CNRS, Université de Paris Sud, F-91405 Orsay (France); Méot, F. [BNL, Upton, Long Island, New York (United States); Serani, L. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Stodel, M.-H.; Varenne, F. [GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); and others

    2013-12-15

    DESIR is the low-energy part of the SPIRAL2 ISOL facility under construction at GANIL. DESIR includes a high-resolution mass separator (HRS) with a designed resolving power m/Δm of 31,000 for a 1 π-mm-mrad beam emittance, obtained using a high-intensity beam cooling device. The proposed design consists of two 90-degree magnetic dipoles, complemented by electrostatic quadrupoles, sextupoles, and a multipole, arranged in a symmetric configuration to minimize aberrations. A detailed description of the design and results of extensive simulations are given.

  15. Band-notched spiral antenna

    Science.gov (United States)

    Jeon, Jae; Chang, John

    2018-03-13

    A band-notched spiral antenna having one or more spiral arms extending from a radially inner end to a radially outer end for transmitting or receiving electromagnetic radiation over a frequency range, and one or more resonance structures positioned adjacent one or more segments of the spiral arm associated with a notch frequency band or bands of the frequency range so as to resonate and suppress the transmission or reception of electromagnetic radiation over said notch frequency band or bands.

  16. Nature of galaxy spiral arms

    International Nuclear Information System (INIS)

    Efremov, Yu.N.

    1984-01-01

    The nature of galaxy spiral arms is discussed in a popular form. Two approaches in the theory of spiral arms are considered; they are related to the problem of differential galaxy rotation and the spiral structure wave theory. The example of Galaxy M31 is considered to compare the structural peculiarity of its spiral arms with the wave theory predictions. The situation in the central and south-eastern part of arm S4 in Galaxy M31 noted to be completely explained by the wave theory and modern concepts on the origin of massive stars

  17. Measuring nutrient spiralling in streams

    Energy Technology Data Exchange (ETDEWEB)

    Newbold, J D; Elwood, J W; O' Neill, R V; Van Winkle, W

    1981-01-01

    Nutrient cycling in streams involves some downstream transport before the cycle is completed. Thus, the path traveled by a nutrient atom in passing through the cycle can be visualized as a spiral. As an index of the spiralling process, we introduce spiralling length, defined as the average distance associated with one complete cycle of a nutrient atom. This index provides a measure of the utilization of nutrients relative to the available supply from upstream. Using /sup 32/p as a tracer, we estimated a spiralling length of 193 m for phosphorus in a small woodland stream.

  18. Three phase spiral liver Scanning

    International Nuclear Information System (INIS)

    Kanyanja, T.A.

    2006-01-01

    The ability to perform rapid back-to-back spiral acquisitions is an important recent technical advantage of spiral CT. this allows imaging of the upper abdomen (liver) during peak arterial enhancement (arterial phase) and during peak hepatic parenchymal enhancement (portal venous phase). Breatheld spiral CT has completely replaced dynamic incremental CT for evaluation of the liver. in selected patients with hyper vascular metastasis (hepatoma, neuroendocrine tumors, renal cell carcinoma, etc.) a biphasic examination is performed with one spiral acquisition obtained during the hepatic arterial phase and a second acquisition during the portal venous phase

  19. The subtropical nutrient spiral

    Science.gov (United States)

    Jenkins, William J.; Doney, Scott C.

    2003-12-01

    We present an extended series of observations and more comprehensive analysis of a tracer-based measure of new production in the Sargasso Sea near Bermuda using the 3He flux gauge technique. The estimated annually averaged nitrate flux of 0.84 ± 0.26 mol m-2 yr-1 constitutes only that nitrate physically transported to the euphotic zone, not nitrogen from biological sources (e.g., nitrogen fixation or zooplankton migration). We show that the flux estimate is quantitatively consistent with other observations, including decade timescale evolution of the 3H + 3He inventory in the main thermocline and export production estimates. However, we argue that the flux cannot be supplied in the long term by local diapycnal or isopycnal processes. These considerations lead us to propose a three-dimensional pathway whereby nutrients remineralized within the main thermocline are returned to the seasonally accessible layers within the subtropical gyre. We describe this mechanism, which we call "the nutrient spiral," as a sequence of steps where (1) nutrient-rich thermocline waters are entrained into the Gulf Stream, (2) enhanced diapycnal mixing moves nutrients upward onto lighter densities, (3) detrainment and enhanced isopycnal mixing injects these waters into the seasonally accessible layer of the gyre recirculation region, and (4) the nutrients become available to biota via eddy heaving and wintertime convection. The spiral is closed when nutrients are utilized, exported, and then remineralized within the thermocline. We present evidence regarding the characteristics of the spiral and discuss some implications of its operation within the biogeochemical cycle of the subtropical ocean.

  20. Rebuilding Spiral Galaxies

    Science.gov (United States)

    2005-01-01

    Major Observing Programme Leads to New Theory of Galaxy Formation Summary Most present-day large galaxies are spirals, presenting a disc surrounding a central bulge. Famous examples are our own Milky Way or the Andromeda Galaxy. When and how did these spiral galaxies form? Why do a great majority of them present a massive central bulge? An international team of astronomers [1] presents new convincing answers to these fundamental questions. For this, they rely on an extensive dataset of observations of galaxies taken with several space- and ground-based telescopes. In particular, they used over a two-year period, several instruments on ESO's Very Large Telescope. Among others, their observations reveal that roughly half of the present-day stars were formed in the period between 8,000 million and 4,000 million years ago, mostly in episodic burst of intense star formation occurring in Luminous Infrared Galaxies. From this and other evidence, the astronomers devised an innovative scenario, dubbed the "spiral rebuilding". They claim that most present-day spiral galaxies are the results of one or several merger events. If confirmed, this new scenario could revolutionise the way astronomers think galaxies formed. PR Photo 02a/05: Luminosity - Oxygen Abundance Relation for Galaxies (VLT) PR Photo 02b/05: The Spiral Rebuilding Scenario A fleet of instruments How and when did galaxies form? How and when did stars form in these island universes? These questions are still posing a considerable challenge to present-day astronomers. Front-line observational results obtained with a fleet of ground- and space-based telescopes by an international team of astronomers [1] provide new insights into these fundamental issues. For this, they embarked on an ambitious long-term study at various wavelengths of 195 galaxies with a redshift [2] greater than 0.4, i.e. located more than 4000 million light-years away. These galaxies were studied using ESO's Very Large Telescope, as well as the

  1. Spiral branches and star formation

    International Nuclear Information System (INIS)

    Zasov, A.V.

    1974-01-01

    Origin of spiral branches of galaxies and formation of stars in them are considered from the point of view of the theory of the gravitational gas condensation, one of comparatively young theories. Arguments are presented in favour of the stellar condensation theory. The concept of the star formation of gas is no longer a speculative hypothesis. This is a theory which assumes quantitative verification and explains qualitatively many facts observed. And still our knowledge on the nature of spiral branches is very poor. It still remains vague what processes give origin to spiral branches, why some galaxies have spirals and others have none. And shapes of spiral branches are diverse. Some cases are known when spiral branches spread outside boundaries of galaxies themselves. Such spirals arise exclusively in the region where there are two or some interacting galaxies. Only first steps have been made in the explanation of the galaxy spiral branches, and it is necessary to carry out new observations and new theoretical calculations

  2. Global extinction in spiral galaxies

    NARCIS (Netherlands)

    Tully, RB; Pierce, MJ; Saunders, W; Verheijen, MAW; Witchalls, PL

    Magnitude-limited samples of spiral galaxies drawn from the Ursa Major and Pisces Clusters are used to determine their extinction properties as a function of inclination. Imaging photometry is available for 87 spirals in the B, R, I, and K' bands. Extinction causes systematic scatter in

  3. The perfect shape spiral stories

    CERN Document Server

    Hammer, Øyvind

    2016-01-01

    This book uses the spiral shape as a key to a multitude of strange and seemingly disparate stories about art, nature, science, mathematics, and the human endeavour. In a way, the book is itself organized as a spiral, with almost disconnected chapters circling around and closing in on the common theme. A particular strength of the book is its extremely cross-disciplinary nature - everything is fun, and everything is connected! At the same time, the author puts great emphasis on mathematical and scientific correctness, in contrast, perhaps, with some earlier books on spirals. Subjects include the mathematical properties of spirals, sea shells, sun flowers, Greek architecture, air ships, the history of mathematics, spiral galaxies, the anatomy of the human hand, the art of prehistoric Europe, Alfred Hitchcock, and spider webs, to name a few.

  4. Spiral waves characterization: Implications for an automated cardiodynamic tissue characterization.

    Science.gov (United States)

    Alagoz, Celal; Cohen, Andrew R; Frisch, Daniel R; Tunç, Birkan; Phatharodom, Saran; Guez, Allon

    2018-07-01

    Spiral waves are phenomena observed in cardiac tissue especially during fibrillatory activities. Spiral waves are revealed through in-vivo and in-vitro studies using high density mapping that requires special experimental setup. Also, in-silico spiral wave analysis and classification is performed using membrane potentials from entire tissue. In this study, we report a characterization approach that identifies spiral wave behaviors using intracardiac electrogram (EGM) readings obtained with commonly used multipolar diagnostic catheters that perform localized but high-resolution readings. Specifically, the algorithm is designed to distinguish between stationary, meandering, and break-up rotors. The clustering and classification algorithms are tested on simulated data produced using a phenomenological 2D model of cardiac propagation. For EGM measurements, unipolar-bipolar EGM readings from various locations on tissue using two catheter types are modeled. The distance measure between spiral behaviors are assessed using normalized compression distance (NCD), an information theoretical distance. NCD is a universal metric in the sense it is solely based on compressibility of dataset and not requiring feature extraction. We also introduce normalized FFT distance (NFFTD) where compressibility is replaced with a FFT parameter. Overall, outstanding clustering performance was achieved across varying EGM reading configurations. We found that effectiveness in distinguishing was superior in case of NCD than NFFTD. We demonstrated that distinct spiral activity identification on a behaviorally heterogeneous tissue is also possible. This report demonstrates a theoretical validation of clustering and classification approaches that provide an automated mapping from EGM signals to assessment of spiral wave behaviors and hence offers a potential mapping and analysis framework for cardiac tissue wavefront propagation patterns. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Lopsided spiral galaxies

    International Nuclear Information System (INIS)

    Jog, Chanda J.; Combes, Francoise

    2009-01-01

    The light distribution in the disks of many galaxies is 'lopsided' with a spatial extent much larger along one half of a galaxy than the other, as seen in M101. Recent observations show that the stellar disk in a typical spiral galaxy is significantly lopsided, indicating asymmetry in the disk mass distribution. The mean amplitude of lopsidedness is 0.1, measured as the Fourier amplitude of the m=1 component normalized to the average value. Thus, lopsidedness is common, and hence it is important to understand its origin and dynamics. This is a new and exciting area in galactic structure and dynamics, in contrast to the topic of bars and two-armed spirals (m=2) which has been extensively studied in the literature. Lopsidedness is ubiquitous and occurs in a variety of settings and tracers. It is seen in both stars and gas, in the outer disk and the central region, in the field and the group galaxies. The lopsided amplitude is higher by a factor of two for galaxies in a group. The lopsidedness has a strong impact on the dynamics of the galaxy, its evolution, the star formation in it, and on the growth of the central black hole and on the nuclear fuelling. We present here an overview of the observations that measure the lopsided distribution, as well as the theoretical progress made so far to understand its origin and properties. The physical mechanisms studied for its origin include tidal encounters, gas accretion and a global gravitational instability. The related open, challenging problems in this emerging area are discussed

  6. Arsia Mons Spiral Cloud

    Science.gov (United States)

    2002-01-01

    One of the benefits of the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) Extended Mission is the opportunity to observe how the planet's weather changes during a second full martian year. This picture of Arsia Mons was taken June 19, 2001; southern spring equinox occurred the same day. Arsia Mons is a volcano nearly large enough to cover the state of New Mexico. On this particular day (the first day of Spring), the MOC wide angle cameras documented an unusual spiral-shaped cloud within the 110 km (68 mi) diameter caldera--the summit crater--of the giant volcano. Because the cloud is bright both in the red and blue images acquired by the wide angle cameras, it probably consisted mostly of fine dust grains. The cloud's spin may have been induced by winds off the inner slopes of the volcano's caldera walls resulting from the temperature differences between the walls and the caldera floor, or by a vortex as winds blew up and over the caldera. Similar spiral clouds were seen inside the caldera for several days; we don't know if this was a single cloud that persisted throughout that time or one that regenerated each afternoon. Sunlight illuminates this scene from the left/upper left.Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  7. Configuration Management

    International Nuclear Information System (INIS)

    Morcos, A.; Taylor, H. S.

    1989-01-01

    This paper will briefly discuss the reason for and content of configuration management both for new plants and, when adapted, for older plants. It will then address three types of activities a utility may undertake as part of a nuclear CAM program and with which Sargent and Leyden has been actively involved. The first activity is a methodology for preparing design-basis documentation. The second is the identification of essential data required to be kept by the utility in support of the operation of a nuclear plant. The third activity is a computerized classification system of plant components, allowing ready identification of plant functional and physical characteristics. Plant configuration documentation describes plant components, the ways they arranged to interact, and the ways they are enabled to interact. Configuration management, on the other hand, is more than the control of such documentation. It is a dynamic process for ensuring that a plant configuration meets all relevant requirements for safety and economy, even while the configuration changes and even while the requirements change. Configuration management for a nuclear plant is so complex that it must be implemented in phases and modules. It takes advantage of and integrates existing programs. Managing complexity and streamlining the change process become important additional objectives of configuration management. The example activities fulfill essential goals of an overall CAM program: definition of design baseline, definition of essential plant data, and classification of plant components

  8. Nonplanar spiral states of the t-J model with classical spins

    International Nuclear Information System (INIS)

    Hamada, M.; Shimahara, H.; Mori, H.

    1995-01-01

    The spiral state in the two-dimensional t-J model is studied by numerical diagonalization of an effective Hamiltonian. We examine all possibilities of the spiral spin states including the nonplanar states. It is found that nonplanar spiral states occur, but the deviations from the planar spiral state in the nonplanar spiral states are small for small hole concentrations where our effective Hamiltonian is valid. The modulation of the spin configuration increases continuously from the antiferromagnetic order as the hole concentration increases, and discontinuously changes at a critical hole concentration. Then the state undergoes the first-order phase transition either to the (π,0) phase or to the ferromagnetic phase, depending on the value of J/t

  9. Polarization study of spiral galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Ward-Thompson, D

    1987-01-01

    Optical polarimetry results are presented for four spiral galaxies: NGC 5194 (M51), NGC 1068, NGC 4565 and NGC 4594 (M104). M51 and NGC 1068 show spiral polarization patterns interpreted as indicating a spiral magnetic field in each case. NGC 4565 and M104 show polarizations in their dust lanes which are parallel to their galactic planes, and which are interpreted in terms of a magnetic field in the plane of each. It is hypothesized that the observed magnetic fields may be linked to galactic shocks. A discussion of the origin of galactic magnetic fields concludes that there is not evidence that necessitates a primordial magnetic field.

  10. Spiral phases of doped antiferromagnets

    International Nuclear Information System (INIS)

    Shraiman, B.I.; Siggia, E.D.

    1990-01-01

    The dipole density field describing the holls in a doped antiferromagnet is considered for law hole density in the semiclassical limit. This yields a phase in which the order parameter is planar and spirals round a fixed direction. The single spiral state breaks the continuous spin rotational symmetry and exhibits long-range order at zero temperature. In it there is a global spin direction as rotation axis. The double spiral state, in which there are two perpendicular directions, is isotropic in both spin and real space. Several results of microscopic calculations, carried out to understand the electronic states, quantum fluctuations, lattice effects and normal mode dynamics, are recapitulated. 8 refs

  11. Spiral-shaped disinfection reactors

    KAUST Repository

    Ghaffour, NorEddine; Ait-Djoudi, Fariza; Naceur, Wahib Mohamed; Soukane, Sofiane

    2015-01-01

    This disclosure includes disinfection reactors and processes for the disinfection of water. Some disinfection reactors include a body that defines an inlet, an outlet, and a spiral flow path between the inlet and the outlet, in which the body

  12. TURBULENCE AND STAR FORMATION IN A SAMPLE OF SPIRAL GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Maier, Erin; Chien, Li-Hsin [Department of Physics and Astronomy, Northern Arizona University 527 S Beaver Street, Flagstaff, AZ 86011 (United States); Hunter, Deidre A., E-mail: erin-maier@uiowa.edu, E-mail: Lisa.Chien@nau.edu, E-mail: dah@lowell.edu [Lowell Observatory 1400 W Mars Hill Road, Flagstaff, AZ 86001 (United States)

    2016-11-01

    We investigate turbulent gas motions in spiral galaxies and their importance to star formation in far outer disks, where the column density is typically far below the critical value for spontaneous gravitational collapse. Following the methods of Burkhart et al. on the Small Magellanic Cloud, we use the third and fourth statistical moments, as indicators of structures caused by turbulence, to examine the neutral hydrogen (H i) column density of a sample of spiral galaxies selected from The H i Nearby Galaxy Survey. We apply the statistical moments in three different methods—the galaxy as a whole, divided into a function of radii and then into grids. We create individual grid maps of kurtosis for each galaxy. To investigate the relation between these moments and star formation, we compare these maps with their far-ultraviolet images taken by the Galaxy Evolution Explorer satellite.We find that the moments are largely uniform across the galaxies, in which the variation does not appear to trace any star-forming regions. This may, however, be due to the spatial resolution of our analysis, which could potentially limit the scale of turbulent motions that we are sensitive to greater than ∼700 pc. From comparison between the moments themselves, we find that the gas motions in our sampled galaxies are largely supersonic. This analysis also shows that the Burkhart et al. methods may be applied not just to dwarf galaxies but also to normal spiral galaxies.

  13. Dynamic effects of diabatization in distillation columns

    DEFF Research Database (Denmark)

    Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens

    2013-01-01

    The dynamic effects of diabatization in distillation columns are investigated in simulation emphasizing the heat-integrated distillation column (HIDiC). A generic, dynamic, first-principle model has been formulated, which is flexible enough to describe various diabatic distillation configurations....... Dynamic Relative Gain Array and Singular Value Analysis have been applied in a comparative study of a conventional distillation column and a HIDiC. The study showed increased input-output coupling due to diabatization. Feasible SISO control structures for the HIDiC were also found and control...

  14. Orientation decoding: Sense in spirals?

    Science.gov (United States)

    Clifford, Colin W G; Mannion, Damien J

    2015-04-15

    The orientation of a visual stimulus can be successfully decoded from the multivariate pattern of fMRI activity in human visual cortex. Whether this capacity requires coarse-scale orientation biases is controversial. We and others have advocated the use of spiral stimuli to eliminate a potential coarse-scale bias-the radial bias toward local orientations that are collinear with the centre of gaze-and hence narrow down the potential coarse-scale biases that could contribute to orientation decoding. The usefulness of this strategy is challenged by the computational simulations of Carlson (2014), who reported the ability to successfully decode spirals of opposite sense (opening clockwise or counter-clockwise) from the pooled output of purportedly unbiased orientation filters. Here, we elaborate the mathematical relationship between spirals of opposite sense to confirm that they cannot be discriminated on the basis of the pooled output of unbiased or radially biased orientation filters. We then demonstrate that Carlson's (2014) reported decoding ability is consistent with the presence of inadvertent biases in the set of orientation filters; biases introduced by their digital implementation and unrelated to the brain's processing of orientation. These analyses demonstrate that spirals must be processed with an orientation bias other than the radial bias for successful decoding of spiral sense. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Configuration management

    International Nuclear Information System (INIS)

    Beavers, R.R.; Sumiec, K.F.

    1989-01-01

    Increasing regulatory and industry attention has been focused on properly controlling electrical design changes. These changes can be controlled by using configuration management techniques. Typically, there are ongoing modifications to various process systems or additions due to new requirements at every power plant. Proper control of these changes requires that an organized method be used to ensure that all important parameters of the electrical auxiliary systems are analyzed and that these parameters are evaluated accurately. This process, commonly referred to as configuration management, is becoming more important on both fossil and nuclear plants. Recent NRC- and utility-initiated inspections have identified problems due to incomplete analysis of changes to electrical auxiliary systems at nuclear stations

  16. Origins of galactic spiral structures

    International Nuclear Information System (INIS)

    Piddington, J.H.

    1978-01-01

    Theories of galactic structure are reviewed briefly before comparing them with recent observations. Also reviewed is the evidence for an intergalactic magnetic field and its possible effects on gas concentrations and patterns of star creation, including spiral arms. It is then shown that normal spiral galaxies may be divided into the M51-type and others. The rare M51-type have H I gas arms coincident with unusually filamentary and luminous optical arms; they also have a companion galaxy. The remaining great majority of spirals have no well-defined gas arms and their optical arms are irregular, broader and less luminous; they have no companion galaxy. It appears that without exception the half-dozen or so galaxies whose structures appear to support the density-wave theory show one or more of the characteristics of the rare type of spiral, and that 'the three principal confirmations of the spiral-wave idea' (M51, M81, M101) have companions which may account for their arms. Toomre has rejected this idea on the grounds that his models do not agree with the observed structures. It is shown that these models are inadequate in two major respects, and when replaced by magneto-tidal models using non-uniform gas disks one might expect agreement. The original hydromagnetic model of spiral arms is now reserved for non-interacting galaxies, of which M33 might be taken as a prototype. The model predicts broad or 'massive' optical arms and no corresponding arms of neutral hydrogen, as observed. (Auth.)

  17. Dark matter in spiral galaxies

    International Nuclear Information System (INIS)

    Persic, M.; Salucci, P.

    1990-01-01

    The Tully-Fisher relation is used to probe dark matter (DM) in the optical regions of spiral galaxies. By establishing it at several different isophotal radii in an appropriate sample of 58 galaxies with good B-band photometry and rotation curves, it is shown that some of its attributes (such as scatter, residuals, nonlinearity, and bias) dramatically decrease moving from the disk edge inward. This behavior challenges any mass model which assumes no DM or a luminosity-independent DM mass fraction interior to the optical radius of spiral galaxies. 58 refs

  18. Modeling Stone Columns.

    Science.gov (United States)

    Castro, Jorge

    2017-07-11

    This paper reviews the main modeling techniques for stone columns, both ordinary stone columns and geosynthetic-encased stone columns. The paper tries to encompass the more recent advances and recommendations in the topic. Regarding the geometrical model, the main options are the "unit cell", longitudinal gravel trenches in plane strain conditions, cylindrical rings of gravel in axial symmetry conditions, equivalent homogeneous soil with improved properties and three-dimensional models, either a full three-dimensional model or just a three-dimensional row or slice of columns. Some guidelines for obtaining these simplified geometrical models are provided and the particular case of groups of columns under footings is also analyzed. For the latter case, there is a column critical length that is around twice the footing width for non-encased columns in a homogeneous soft soil. In the literature, the column critical length is sometimes given as a function of the column length, which leads to some disparities in its value. Here it is shown that the column critical length mainly depends on the footing dimensions. Some other features related with column modeling are also briefly presented, such as the influence of column installation. Finally, some guidance and recommendations are provided on parameter selection for the study of stone columns.

  19. Quasicrystallography on the spiral of Archimedes

    International Nuclear Information System (INIS)

    Bursill, L.A.

    1990-01-01

    The concept of a spiral lattice is discussed. Some examples of known mineral structures, namely clino asbestos, halloysite and cylindrite, are then interpreted in terms of this structural principle. An example of a synthetic sulphide catalyst spiral structure having atomic dimensions is also described. All of these inorganic spiral structures are based on the sprial of Archimedes. The principles for a new type of crystallography, based on the Archimedian spiral, are then presented. 45 refs., 8 figs

  20. ( Anogeissus leiocarpus ) timber columns

    African Journals Online (AJOL)

    A procedure for designing axially loaded Ayin (Anogeissus leiocarpus) wood column or strut has been investigated. Instead of the usual categorization of columns into short, intermediate and slender according to the value of slenderness ratio, a continuous column formula representing the three categories was derived.

  1. Column Liquid Chromatography.

    Science.gov (United States)

    Majors, Ronald E.; And Others

    1984-01-01

    Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

  2. A study of spiral galaxies

    International Nuclear Information System (INIS)

    Wevers, B.M.H.R.

    1984-01-01

    Attempts have been made to look for possible correlations between integral properties of spiral galaxies as a function of morphological type. To investigate this problem, one needs the detailed distribution of both the gaseous and the stellar components for a well-defined sample of spiral galaxies. A sample of about 20 spiral galaxies was therefore defined; these galaxies were observed in the 21 cm neutral hydrogen line with the Westerbork Synthesis Radio Telescope and in three broad-band optical colours with the 48-inch Palomar Smidt Telescope. First, an atlas of the combined radio and optical observations of 16 nearby northern-hemisphere spiral galaxies is presented. Luminosity profiles are discussed and the scale lengths of the exponential disks and extrapolated central surface brightnesses are derived, as well as radial color distributions; azimuthal surface brightness distributions and rotation curves. Possible correlations with optical features are investigated. It is found that 20 to 50 per cent of the total mass is in the disk. (Auth.)

  3. The Spiral Pattern During Development*

    African Journals Online (AJOL)

    1971-08-07

    Aug 7, 1971 ... which are destined to become the limb areas bud out laterally. Fig. 8. The early cells, which are destined to develop into the upper and the lower limbs, after lateral budding has occurred. Fig. 11 demonstrates the human embryo of about 5 mm. CR length and age of about 32 days. The spiral pattern is.

  4. Chiral spiral waveguides based on MMI crossings: theory and experiments

    Science.gov (United States)

    Cherchi, Matteo; Ylinen, Sami; Harjanne, Mikko; Kapulainen, Markku; Vehmas, Tapani; Aalto, Timo

    2016-03-01

    We introduce a novel type of chiral spiral waveguide where the usual waveguide crossings are replaced by 100:0 Multimode Interferometers (MMIs), i.e. 2x2 splitters that couple all the input light in the cross output port. Despite the topological equivalence with the standard configuration, we show how resorting to long MMIs has non-trivial advantages in terms of footprint and propagation length. An accurate analytic model is also introduced to show the impact of nonidealities on the spiral performances, including propagation loss and cross-talk. We have designed and fabricated three chiral spirals on our platform, based on 3 μm thick silicon strip waveguides with 0.13 dB/cm propagation loss, and 1.58 mm long MMIs. The fabricated spirals have 7, 13 and 49 loops respectively, corresponding to the effective lengths 6.6 cm, 12.5 cm and 47.9 cm. The proposed model is successfully applied to the experimental results, highlighting MMI extinction ratio of about 16.5 dB and MMI loss of about 0.08 dB, that are much worse compared to the simulated 50 dB extinction and 0.01 dB loss. This imposes an upper limit to the number of rounds, because light takes shortcuts through the bar MMI ports. Nevertheless, the novel chiral spiral waveguides outperform what is achievable in mainstream silicon photonics platforms based on submicron waveguides in terms of length and propagation losses, and they are promising candidates for the realization of integrated gyroscopes. They can be significantly further improved by replacing the MMIs with adiabatic 100:0 splitters, ensuring lower cross-talk and broader bandwidth.

  5. TESTING THEORIES IN BARRED-SPIRAL GALAXIES

    International Nuclear Information System (INIS)

    Martínez-García, Eric E.

    2012-01-01

    According to one version of the recently proposed 'manifold' theory that explains the origin of spirals and rings in relation to chaotic orbits, galaxies with stronger bars should have a higher spiral arms pitch angle when compared to galaxies with weaker bars. A subsample of barred-spiral galaxies in the Ohio State University Bright Galaxy Survey was used to analyze the spiral arms pitch angle. These were compared with bar strengths taken from the literature. It was found that the galaxies in which the spiral arms maintain a logarithmic shape for more than 70° seem to corroborate the predicted trend.

  6. Interaction of multiarmed spirals in bistable media.

    Science.gov (United States)

    He, Ya-feng; Ai, Bao-quan; Liu, Fu-cheng

    2013-05-01

    We study the interaction of both dense and sparse multiarmed spirals in bistable media modeled by equations of the FitzHugh-Nagumo type. A dense one-armed spiral is characterized by its fixed tip. For dense multiarmed spirals, when the initial distance between tips is less than a critical value, the arms collide, connect, and disconnect continuously as the spirals rotate. The continuous reconstruction between the front and the back drives the tips to corotate along a rough circle and to meander zigzaggedly. The rotation frequency of tip, the frequency of zigzagged displacement, the frequency of spiral, the oscillation frequency of media, and the number of arms satisfy certain relations as long as the control parameters of the model are fixed. When the initial distance between tips is larger than the critical value, the behaviors of individual arms within either dense or sparse multiarmed spirals are identical to that of corresponding one-armed spirals.

  7. Large scale filaments associated with Milky Way spiral arms

    Science.gov (United States)

    Wang, Ke; Testi, Leonardo; Ginsburg, Adam; Walmsley, Malcolm; Molinari, Sergio; Schisano, Eugenio

    2015-08-01

    The ubiquity of filamentary structure at various scales through out the Galaxy has triggered a renewed interest in their formation, evolution, and role in star formation. The largest filaments can reach up to Galactic scale as part of the spiral arm structure. However, such large scale filaments are hard to identify systematically due to limitations in identifying methodology (i.e., as extinction features). We present a new approach to directly search for the largest, coldest, and densest filaments in the Galaxy, making use of sensitive Herschel Hi-GAL data complemented by spectral line cubes. We present a sample of the 9 most prominent Herschel filaments from a pilot search field. These filaments measure 37-99 pc long and 0.6-3.0 pc wide with masses (0.5-8.3)×104 Msun, and beam-averaged (28", or 0.4-0.7 pc) peak H2 column densities of (1.7-9.3)x1022 cm-2. The bulk of the filaments are relatively cold (17-21 K), while some local clumps have a dust temperature up to 25-47 K due to local star formation activities. All the filaments are located within spiral arm model incorporating the latest parallax measurements, we find that 7/9 of them reside within arms, but most are close to arm edges. These filaments are comparable in length to the Galactic scale height and therefore are not simply part of a grander turbulent cascade. These giant filaments, which often contain regularly spaced pc-scale clumps, are much larger than the filaments found in the Herschel Gould's Belt Survey, and they form the upper ends in the filamentary hierarchy. Full operational ALMA and NOEMA will be able to resolve and characterize similar filaments in nearby spiral galaxies, allowing us to compare the star formation in a uniform context of spiral arms.

  8. Low surface brightness spiral galaxies

    International Nuclear Information System (INIS)

    Romanishin, W.

    1980-01-01

    This dissertation presents an observational overview of a sample of low surface brightness (LSB) spiral galaxies. The sample galaxies were chosen to have low surface brightness disks and indications of spiral structure visible on the Palomar Sky Survey. They are of sufficient angular size (diameter > 2.5 arcmin), to allow detailed surface photometry using Mayall 4-m prime focus plates. The major findings of this dissertation are: (1) The average disk central surface brightness of the LSB galaxies is 22.88 magnitude/arcsec 2 in the B passband. (2) From broadband color measurements of the old stellar population, we infer a low average stellar metallicity, on the order of 1/5 solar. (3) The spectra and optical colors of the HII regions in the LSB galaxies indicate a lack of hot ionizing stars compared to HII regions in other late-type galaxies. (4) The average surface mass density, measured within the radius containing half the total mass, is less than half that of a sample of normal late-type spirals. (5) The average LSB galaxy neutral hydrogen mass to blue luminosity ratio is about 0.6, significantly higher than in a sample of normal late-type galaxies. (6) We find no conclusive evidence of an abnormal mass-to-light ratio in the LSB galaxies. (7) Some of the LSB galaxies exhibit well-developed density wave patterns. (8) A very crude calculation shows the lower metallicity of the LSB galaxies compared with normal late-type spirals might be explained simply by the deficiency of massive stars in the LSB galaxies

  9. Dynamical models of spiral galaxies

    International Nuclear Information System (INIS)

    Grosbol, P.

    1990-01-01

    The effects of changing the basic parameters of rotation curve steepness, amount of bulge, and pitch angle of the imposed spiral pattern in the galactic model of Contoupolos and Grosbel (1986) are investigated. The general conclusions of the model are confirmed and shown to be insensitive to the specific choice of parameters for the galactic potential. The exact amplitude at which the nonlinear effects at the 4:1 resonance become important do, however, depend on the model

  10. Multiple mechanisms quench passive spiral galaxies

    Science.gov (United States)

    Fraser-McKelvie, Amelia; Brown, Michael J. I.; Pimbblet, Kevin; Dolley, Tim; Bonne, Nicolas J.

    2018-02-01

    We examine the properties of a sample of 35 nearby passive spiral galaxies in order to determine their dominant quenching mechanism(s). All five low-mass (M⋆ environments. We postulate that cluster-scale gas stripping and heating mechanisms operating only in rich clusters are required to quench low-mass passive spirals, and ram-pressure stripping and strangulation are obvious candidates. For higher mass passive spirals, while trends are present, the story is less clear. The passive spiral bar fraction is high: 74 ± 15 per cent, compared with 36 ± 5 per cent for a mass, redshift and T-type matched comparison sample of star-forming spiral galaxies. The high mass passive spirals occur mostly, but not exclusively, in groups, and can be central or satellite galaxies. The passive spiral group fraction of 74 ± 15 per cent is similar to that of the comparison sample of star-forming galaxies at 61 ± 7 per cent. We find evidence for both quenching via internal structure and environment in our passive spiral sample, though some galaxies have evidence of neither. From this, we conclude no one mechanism is responsible for quenching star formation in passive spiral galaxies - rather, a mixture of mechanisms is required to produce the passive spiral distribution we see today.

  11. Gas Chromatograph Method Optimization Trade Study for RESOLVE: 20-meter Column v. 8-meter Column

    Science.gov (United States)

    Huz, Kateryna

    2014-01-01

    RESOLVE is the payload on a Class D mission, Resource Prospector, which will prospect for water and other volatile resources at a lunar pole. The RESOLVE payload's primary scientific purpose includes determining the presence of water on the moon in the lunar regolith. In order to detect the water, a gas chromatograph (GC) will be used in conjunction with a mass spectrometer (MS). The goal of the experiment was to compare two GC column lengths and recommend which would be best for RESOLVE's purposes. Throughout the experiment, an Inficon Fusion GC and an Inficon Micro GC 3000 were used. The Fusion had a 20m long column with 0.25mm internal diameter (Id). The Micro GC 3000 had an 8m long column with a 0.32mm Id. By varying the column temperature and column pressure while holding all other parameters constant, the ideal conditions for testing with each column length in their individual instrument configurations were determined. The criteria used for determining the optimal method parameters included (in no particular order) (1) quickest run time, (2) peak sharpness, and (3) peak separation. After testing numerous combinations of temperature and pressure, the parameters for each column length that resulted in the most optimal data given my three criteria were selected. The ideal temperature and pressure for the 20m column were 95 C and 50psig. At this temperature and pressure, the peaks were separated and the retention times were shorter compared to other combinations. The Inficon Micro GC 3000 operated better at lower temperature mainly due to the shorter 8m column. The optimal column temperature and pressure were 70 C and 30psig. The Inficon Micro GC 3000 8m column had worse separation than the Inficon Fusion 20m column, but was able to separate water within a shorter run time. Therefore, the most significant tradeoff between the two column lengths was peak separation of the sample versus run time. After performing several tests, it was concluded that better

  12. Confinement of NORMAL- AND HIGH-STRENGTH CONCRETE by Shape Memory Alloy (SMA) Spirals

    Science.gov (United States)

    Gholampour, A.; Ozbakkaloglu, T.

    2018-01-01

    This paper presents the results of an experimental study on the axial compressive behaviour of normal- and high-strength concrete (NSC and HSC) confined by shape memory alloy (SMA) spirals. A spiral pitch space of 36 and 20 mm was used for SMA confinement of NSC and HSC columns, respectively. The confining pressure was applied on the concrete cylinders by SMA spirals that were prestrained at 0, 5.5, and 9.5%. The compression test results on the SMA-confined specimens indicate that the prestrain level of SMA significantly affects the axial compressive behaviour of both NSC and HSC. An increase in the level of prestrain leads to an increase in the peak axial stress and corresponding strain of SMA-confined concrete.

  13. Collective excitations in itinerant spiral magnets

    International Nuclear Information System (INIS)

    Kampf, A.P.

    1996-01-01

    We investigate the coupled charge and spin collective excitations in the spiral phases of the two-dimensional Hubbard model using a generalized random-phase approximation. Already for small doping the spin-wave excitations are strongly renormalized due to low-energy particle-hole excitations. Besides the three Goldstone modes of the spiral state the dynamical susceptibility reveals an extra zero mode for low doping and strong coupling values signaling an intrinsic instability of the homogeneous spiral state. In addition, near-zero modes are found in the vicinity of the spiral pitch wave number for out-of-plane spin fluctuations. Their origin is found to be the near degeneracy with staggered noncoplanar spiral states which, however, are not the lowest energy Hartree-Fock solutions among the homogeneous spiral states. copyright 1996 The American Physical Society

  14. Analisa Kekuatan Spiral Bevel Gear Dengan Variasi Sudut Spiral Menggunakan Metode Elemen Hingga

    OpenAIRE

    Deta Rachmat Andika; Agus Sigit Pramono

    2017-01-01

    Seiring perkembangan zaman,  teknologi roda gigi dituntut untuk mampu mentransmisikan daya yang besar dengan efisiensi yang besar pula. Pada jenis intersecting shaft gear, tipe roda gigi payung spiral (spiral bevel gear)  merupakan perkembangan dari roda gigi payung bergigi lurus (straight bevel gear). Kelebihan dari spiral bevel gear antara  lain adalah kemampuan transmisi daya dan efisiensi yang lebih besar pada geometri yang sama serta tidak terlalu berisik. Akan tetapi spiral bevel gear j...

  15. Solvable model of spiral wave chimeras.

    Science.gov (United States)

    Martens, Erik A; Laing, Carlo R; Strogatz, Steven H

    2010-01-29

    Spiral waves are ubiquitous in two-dimensional systems of chemical or biological oscillators coupled locally by diffusion. At the center of such spirals is a phase singularity, a topological defect where the oscillator amplitude drops to zero. But if the coupling is nonlocal, a new kind of spiral can occur, with a circular core consisting of desynchronized oscillators running at full amplitude. Here, we provide the first analytical description of such a spiral wave chimera and use perturbation theory to calculate its rotation speed and the size of its incoherent core.

  16. Evolutionary Acquisition and Spiral Development Tutorial

    National Research Council Canada - National Science Library

    Hantos, P

    2005-01-01

    .... NSS Acquisition Policy 03-01 provided some space-oriented customization and, similarly to the original DOD directives, also positioned Evolutionary Acquisition and Spiral Development as preferred...

  17. Solvable Model of Spiral Wave Chimeras

    DEFF Research Database (Denmark)

    Martens, Erik Andreas; Laing, Carlo R.; Strogatz, Steven H.

    2010-01-01

    Spiral waves are ubiquitous in two-dimensional systems of chemical or biological oscillators coupled locally by diffusion. At the center of such spirals is a phase singularity, a topological defect where the oscillator amplitude drops to zero. But if the coupling is nonlocal, a new kind of spiral...... can occur, with a circular core consisting of desynchronized oscillators running at full amplitude. Here, we provide the first analytical description of such a spiral wave chimera and use perturbation theory to calculate its rotation speed and the size of its incoherent core....

  18. JCE Feature Columns

    Science.gov (United States)

    Holmes, Jon L.

    1999-05-01

    The Features area of JCE Online is now readily accessible through a single click from our home page. In the Features area each column is linked to its own home page. These column home pages also have links to them from the online Journal Table of Contents pages or from any article published as part of that feature column. Using these links you can easily find abstracts of additional articles that are related by topic. Of course, JCE Online+ subscribers are then just one click away from the entire article. Finding related articles is easy because each feature column "site" contains links to the online abstracts of all the articles that have appeared in the column. In addition, you can find the mission statement for the column and the email link to the column editor that I mentioned above. At the discretion of its editor, a feature column site may contain additional resources. As an example, the Chemical Information Instructor column edited by Arleen Somerville will have a periodically updated bibliography of resources for teaching and using chemical information. Due to the increase in the number of these resources available on the WWW, it only makes sense to publish this information online so that you can get to these resources with a simple click of the mouse. We expect that there will soon be additional information and resources at several other feature column sites. Following in the footsteps of the Chemical Information Instructor, up-to-date bibliographies and links to related online resources can be made available. We hope to extend the online component of our feature columns with moderated online discussion forums. If you have a suggestion for an online resource you would like to see included, let the feature editor or JCE Online (jceonline@chem.wisc.edu) know about it. JCE Internet Features JCE Internet also has several feature columns: Chemical Education Resource Shelf, Conceptual Questions and Challenge Problems, Equipment Buyers Guide, Hal's Picks, Mathcad

  19. Spiral 2 the scientific objectives

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-06-15

    The French ministry of research took the decision to build Spiral-2 in May 2005. Its construction costs are estimated to 130 million euros while its operating costs will near 8.5 million euros per year. The construction works will last 5 years. The Spiral-2 facility is based on a high power, superconducting driver Linac, which will deliver a high intensity, 40 MeV deuteron beam as well as a variety of heavy-ion beams with mass over charge ratio equal to 3 and energy up to 14.5 MeV/nucleon. Using a carbon converter, fast neutrons from the breakup of the 5 mA of deuterons impinging on a uranium carbide target will induce a rate of up to 10{sup 14} fissions/s. The radioactive ion beam intensities in the mass range from A = 60 to 140 will be of the order of 10{sup 6} to 10{sup 11} particles/s surpassing by one or two orders-of-magnitude any existing facility in the world. A direct irradiation of the UC{sub 2} target with {sup 3,4}He, {sup 6,7}Li or {sup 12}C may also be used. Different production targets will be used to produce high-intensity beams of light radioactive species with the Isol technique. The extracted radioactive ion beam will be accelerated to energies up to 20 MeV/nucleons by the existing Cime cyclotron. One of the most important features of the future Ganil accelerator complex will be the capability of delivering up to 5 stable or radioactive beams simultaneously in the energy range from the keV to several tens of MeV/nucleons. The document details also the future contribution of Spiral-2 concerning the structure of exotic nuclei, the thermodynamical aspects of nuclear matter, nucleosynthesis, the fundamental basic interactions, and the use of neutrons. (A.C.)

  20. Spiral 2 the scientific objectives

    International Nuclear Information System (INIS)

    2006-06-01

    The French ministry of research took the decision to build Spiral-2 in May 2005. Its construction costs are estimated to 130 million euros while its operating costs will near 8.5 million euros per year. The construction works will last 5 years. The Spiral-2 facility is based on a high power, superconducting driver Linac, which will deliver a high intensity, 40 MeV deuteron beam as well as a variety of heavy-ion beams with mass over charge ratio equal to 3 and energy up to 14.5 MeV/nucleon. Using a carbon converter, fast neutrons from the breakup of the 5 mA of deuterons impinging on a uranium carbide target will induce a rate of up to 10 14 fissions/s. The radioactive ion beam intensities in the mass range from A = 60 to 140 will be of the order of 10 6 to 10 11 particles/s surpassing by one or two orders-of-magnitude any existing facility in the world. A direct irradiation of the UC 2 target with 3,4 He, 6,7 Li or 12 C may also be used. Different production targets will be used to produce high-intensity beams of light radioactive species with the Isol technique. The extracted radioactive ion beam will be accelerated to energies up to 20 MeV/nucleons by the existing Cime cyclotron. One of the most important features of the future Ganil accelerator complex will be the capability of delivering up to 5 stable or radioactive beams simultaneously in the energy range from the keV to several tens of MeV/nucleons. The document details also the future contribution of Spiral-2 concerning the structure of exotic nuclei, the thermodynamical aspects of nuclear matter, nucleosynthesis, the fundamental basic interactions, and the use of neutrons. (A.C.)

  1. The rotation of spiral galaxies.

    Science.gov (United States)

    Rubin, V C

    1983-06-24

    There is accumulating evidence that as much as 90 percent of the mass of the universe is nonluminous and is clumped, halo-like, around individual galaxies. The gravitational force of this dark matter is presumed to be responsible for the high rotational velocities of stars and gas in the disks of spiral galaxie. At present, the form of the dark matter is unknown. Possible candidates span a range in mass of 10(70), from non-zero-mass neutrinos to massive black holes.

  2. Distillation Column Flooding Predictor

    Energy Technology Data Exchange (ETDEWEB)

    George E. Dzyacky

    2010-11-23

    The Flooding Predictor™ is a patented advanced control technology proven in research at the Separations Research Program, University of Texas at Austin, to increase distillation column throughput by over 6%, while also increasing energy efficiency by 10%. The research was conducted under a U. S. Department of Energy Cooperative Agreement awarded to George Dzyacky of 2ndpoint, LLC. The Flooding Predictor™ works by detecting the incipient flood point and controlling the column closer to its actual hydraulic limit than historical practices have allowed. Further, the technology uses existing column instrumentation, meaning no additional refining infrastructure is required. Refiners often push distillation columns to maximize throughput, improve separation, or simply to achieve day-to-day optimization. Attempting to achieve such operating objectives is a tricky undertaking that can result in flooding. Operators and advanced control strategies alike rely on the conventional use of delta-pressure instrumentation to approximate the column’s approach to flood. But column delta-pressure is more an inference of the column’s approach to flood than it is an actual measurement of it. As a consequence, delta pressure limits are established conservatively in order to operate in a regime where the column is never expected to flood. As a result, there is much “left on the table” when operating in such a regime, i.e. the capacity difference between controlling the column to an upper delta-pressure limit and controlling it to the actual hydraulic limit. The Flooding Predictor™, an innovative pattern recognition technology, controls columns at their actual hydraulic limit, which research shows leads to a throughput increase of over 6%. Controlling closer to the hydraulic limit also permits operation in a sweet spot of increased energy-efficiency. In this region of increased column loading, the Flooding Predictor is able to exploit the benefits of higher liquid

  3. Nuclear reactor control column

    International Nuclear Information System (INIS)

    Bachovchin, D.M.

    1982-01-01

    The nuclear reactor control column comprises a column disposed within the nuclear reactor core having a variable cross-section hollow channel and containing balls whose vertical location is determined by the flow of the reactor coolant through the column. The control column is divided into three basic sections wherein each of the sections has a different cross-sectional area. The uppermost section of the control column has the greatest crosssectional area, the intermediate section of the control column has the smallest cross-sectional area, and the lowermost section of the control column has the intermediate cross-sectional area. In this manner, the area of the uppermost section can be established such that when the reactor coolant is flowing under normal conditions therethrough, the absorber balls will be lifted and suspended in a fluidized bed manner in the upper section. However, when the reactor coolant flow falls below a predetermined value, the absorber balls will fall through the intermediate section and into the lowermost section, thereby reducing the reactivity of the reactor core and shutting down the reactor

  4. Improvements in solvent extraction columns

    International Nuclear Information System (INIS)

    Aughwane, K.R.

    1987-01-01

    Solvent extraction columns are used in the reprocessing of irradiated nuclear fuel. For an effective reprocessing operation a solvent extraction column is required which is capable of distributing the feed over most of the column. The patent describes improvements in solvent extractions columns which allows the feed to be distributed over an increased length of column than was previously possible. (U.K.)

  5. The three-dimensional model for helical columns on type-J synchronous counter-current chromatography.

    Science.gov (United States)

    Guan, Y H; van den Heuvel, Remco

    2011-08-05

    Unlike the existing 2-D pseudo-ring model for helical columns undergoing synchronous type-J planetary motion of counter-current chromatograph (CCC), the 3-D "helix" model developed in this work shows that there is a second normal force (i.e. the binormal force) applied virtually in the axial direction of the helical column. This force alternates in the two opposite directions and intensifies phase mixing with increasing the helix angle. On the contrary, the 2-D spiral column operated on the same CCC device lacks this third-dimensional mixing force. The (principal) normal force quantified by this "helix" model has been the same as that by the pseudo-ring model. With β>0.25, this normal centrifugal force has been one-directional and fluctuates cyclically. Different to the spiral column, this "helix" model shows that the centrifugal force (i.e. the hydrostatic force) does not contribute to stationary phase retention in the helical column. Between the popular helical columns and the emerging spiral columns for type-J synchronous CCC, this work has thus illustrated that the former is associated with better phase mixing yet poor retention for the stationary phase whereas the latter has potential for better retention for the stationary phase yet poor phase mixing. The methodology developed in this work may be regarded as a new platform for designing optimised CCC columns for analytical and engineering applications. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Spiral density waves in M81. I. Stellar spiral density waves

    International Nuclear Information System (INIS)

    Feng, Chien-Chang; Lin, Lien-Hsuan; Wang, Hsiang-Hsu; Taam, Ronald E.

    2014-01-01

    Aside from the grand-design stellar spirals appearing in the disk of M81, a pair of stellar spiral arms situated well inside the bright bulge of M81 has been recently discovered by Kendall et al. The seemingly unrelated pairs of spirals pose a challenge to the theory of spiral density waves. To address this problem, we have constructed a three-component model for M81, including the contributions from a stellar disk, a bulge, and a dark matter halo subject to observational constraints. Given this basic state for M81, a modal approach is applied to search for the discrete unstable spiral modes that may provide an understanding for the existence of both spiral arms. It is found that the apparently separated inner and outer spirals can be interpreted as a single trailing spiral mode. In particular, these spirals share the same pattern speed 25.5 km s –1 kpc –1 with a corotation radius of 9.03 kpc. In addition to the good agreement between the calculated and the observed spiral pattern, the variation of the spiral amplitude can also be naturally reproduced.

  7. QS Spiral: Visualizing Periodic Quantified Self Data

    DEFF Research Database (Denmark)

    Larsen, Jakob Eg; Cuttone, Andrea; Jørgensen, Sune Lehmann

    2013-01-01

    In this paper we propose an interactive visualization technique QS Spiral that aims to capture the periodic properties of quantified self data and let the user explore those recurring patterns. The approach is based on time-series data visualized as a spiral structure. The interactivity includes ...

  8. Spiral modes in cold cylindrical systems

    International Nuclear Information System (INIS)

    Robe, H.

    1975-01-01

    The linearized hydrodynamical equations governing the non-axisymmetric free modes of oscillation of cold cylindrical stellar systems are separated in cylindrical coordinates and solved numerically for two models. Short-wavelength unstable modes corresponding to tight spirals do not exist; but there exists an unstable growing mode which has the form of trailing spirals which are quite open. (orig.) [de

  9. Spiral groove seal. [for rotating shaft

    Science.gov (United States)

    Ludwig, L. P.; Strom, T. N. (Inventor)

    1974-01-01

    Mating flat surfaces inhibit leakage of a fluid around a stationary shaft. A spiral groove produces a pumping action toward the fluid when the shaft rotates. This prevents leakage while a generated hydraulic lifting force separates the mating surfaces to minimize wear. Provision is made for placing these spiral grooves in communication with the fluid to accelerate the generation of the hydraulic lifting force.

  10. ANGULAR-MOMENTUM IN BINARY SPIRAL GALAXIES

    NARCIS (Netherlands)

    OOSTERLOO, T

    In order to investigate the relative orientations of spiral galaxies in pairs, the distribution of the angle between the spin-vectors for a new sample of 40 binary spiral galaxies is determined. From this distribution it is found, contrary to an earlier result obtained by Helou (1984), that there is

  11. Colours and morphology of spiral galaxies

    International Nuclear Information System (INIS)

    Wyse, R.F.G.

    1981-01-01

    Tinsley has proposed that late-type spirals have relatively more non-luminous material than early-type spirals. A re-examination of the data indicates that this proposal is equally consistent with dark matter being more dominant in barred galaxies than in unbarred galaxies. Neither conclusion can be firm, since the dataset is far from ideal. (author)

  12. Scaling effects in spiral capsule robots.

    Science.gov (United States)

    Liang, Liang; Hu, Rong; Chen, Bai; Tang, Yong; Xu, Yan

    2017-04-01

    Spiral capsule robots can be applied to human gastrointestinal tracts and blood vessels. Because of significant variations in the sizes of the inner diameters of the intestines as well as blood vessels, this research has been unable to meet the requirements for medical applications. By applying the fluid dynamic equations, using the computational fluid dynamics method, to a robot axial length ranging from 10 -5 to 10 -2  m, the operational performance indicators (axial driving force, load torque, and maximum fluid pressure on the pipe wall) of the spiral capsule robot and the fluid turbulent intensity around the robot spiral surfaces was numerically calculated in a straight rigid pipe filled with fluid. The reasonableness and validity of the calculation method adopted in this study were verified by the consistency of the calculated values by the computational fluid dynamics method and the experimental values from a relevant literature. The results show that the greater the fluid turbulent intensity, the greater the impact of the fluid turbulence on the driving performance of the spiral capsule robot and the higher the energy consumption of the robot. For the same level of size of the robot, the axial driving force, the load torque, and the maximum fluid pressure on the pipe wall of the outer spiral robot were larger than those of the inner spiral robot. For different requirements of the operating environment, we can choose a certain kind of spiral capsule robot. This study provides a theoretical foundation for spiral capsule robots.

  13. Improved reconstruction for IDEAL spiral CSI

    DEFF Research Database (Denmark)

    Hansen, Rie Beck; Mariager, Christian; Laustsen, Christoffer

    2017-01-01

    In this study we demonstrate how reconstruction for IDEAL spiral CSI (spectroscopic imaging scheme developed for hyperpolarized dynamic metabolic MR imaging) can be improved by using regularization with a sparsity constraint. By exploiting sparsity of the spectral domain, IDEAL spiral CSI can...

  14. Buckling of liquid columns

    NARCIS (Netherlands)

    Habibi, M.; Rahmani, Y.; Bonn, D.; Ribe, N.M.

    2010-01-01

    Under appropriate conditions, a column of viscous liquid falling onto a rigid surface undergoes a buckling instability. Here we show experimentally and theoretically that liquid buckling exhibits a hitherto unsuspected complexity involving three different modes—viscous, gravitational, and

  15. Dynamics and Control of Distillation Columns - A Critical Survey

    Directory of Open Access Journals (Sweden)

    Sigurd Skogestad

    1997-07-01

    Full Text Available Distillation column dynamics and control have been viewed by many as a very mature or even dead field. However, as is discussed in this paper significant new results have appeared over the last 5-10 years. These results include multiple steady states and instability in simple columns with ideal thermodynamics (which was believed to be impossible, the understanding of the difference between various control configurations and the systematic transformation between these, the feasibility of using the distillate-bottom structure, for control (which was believed to be impossible, the importance of flow dynamics for control studies, the fundamental problems in identifying models from open-loops responses, the use of simple regression estimators to estimate composition from temperatures, and an improved general understanding of the dynamic behavior of distillation columns which includes a better understanding of the fundamental difference between internal and external flow, simple formulas for estimating the dominant time constant, and a derivation of the linearizing effect of logarithmic transformations. These issues apply to all columns, even for ideal mixtures and simple columns with only two products. In addition, there have been significant advances for cases with complex thermodynamics and complex column configurations. These include the behavior and control of azeotropic distillation columns, and the possible complex dynamics of nonideal mixtures and of interlinked columns. However, both for the simple and more complex cases there are still a number of areas where further research is needed.

  16. Mass of the spirals galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Maupome, L; Pismis, P; Aguilar, L [Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Astronomia

    1981-01-01

    In an earlier paper we have found that the total mass of galaxies-especially of the spirals-based on values published until 1975, decreased as the Hubble type varied from Sa through Sc and Irregulars. It was also pointed out that masses determined from the hydrogen 21-cm line were higher than the optically determined masses. To investigate the cause of these tendencies we have estimated the masses using an analytic rotation curve of Brandt adjusted to the optical observations in order to include all the mass of a galaxy up to the last observed point. Although the masses computed in this manner were found to be larger, as expected, the decrease of mass with Hubble type found earlier is confirmed. However, there is a discrepancy in the earlier types (Sa, Sab) in that their radio-masses are smaller than the optically determined ones. At present, the cause of this is not clear.

  17. Formation of polymeric toroidal-spiral particles.

    Science.gov (United States)

    Sharma, Vishal; Szymusiak, Magdalena; Shen, Hao; Nitsche, Ludwig C; Liu, Ying

    2012-01-10

    Compared to spherical matrices, particles with well-defined internal structure provide large surface to volume ratio and predictable release kinetics for the encapsulated payloads. We describe self-assembly of polymeric particles, whereby competitive kinetics of viscous sedimentation, diffusion, and cross-linking yield a controllable toroidal-spiral (T-S) structure. Precursor polymeric droplets are splashed through the surface of a less dense, miscible solution, after which viscous forces entrain the surrounding bulk solution into the sedimenting polymer drop to form T-S channels. The intricate structure forms because low interfacial tension between the two miscible solutions is dominated by viscous forces. The biocompatible polymer, poly(ethylene glycol) diacrylate (PEG-DA), is used to demonstrate the solidification of the T-S shapes at various configurational stages by UV-triggered cross-linking. The dimensions of the channels are controlled by Weber number during impact on the surface, and Reynolds number and viscosity ratio during subsequent sedimentation. We anticipate applications of the T-S particle in drug delivery, wherein diffusion through these T-S channels and the polymer matrix would offer parallel release pathways for molecules of different sizes. Polyphosphate, as a model macromolecule, is entrained in T-S particles during their formation. The in vitro release kinetics of polyphosphate from the T-S particles with various channel length and width is reported. In addition, self-assembly of T-S particles occurs in a single step under benign conditions for delicate macromolecules, and appears conducive to scaleup.

  18. IMRT delivery verification using a spiral phantom

    International Nuclear Information System (INIS)

    Richardson, Susan L.; Tome, Wolfgang A.; Orton, Nigel P.; McNutt, Todd R.; Paliwal, Bhudatt R.

    2003-01-01

    In this paper we report on the testing and verification of a system for IMRT delivery quality assurance that uses a cylindrical solid water phantom with a spiral trajectory for radiographic film placement. This spiral film technique provides more complete dosimetric verification of the entire IMRT treatment than perpendicular film methods, since it samples a three-dimensional dose subspace rather than using measurements at only one or two depths. As an example, the complete analysis of the predicted and measured spiral films is described for an intracranial IMRT treatment case. The results of this analysis are compared to those of a single field perpendicular film technique that is typically used for IMRT QA. The comparison demonstrates that both methods result in a dosimetric error within a clinical tolerance of 5%, however the spiral phantom QA technique provides a more complete dosimetric verification while being less time consuming. To independently verify the dosimetry obtained with the spiral film, the same IMRT treatment was delivered to a similar phantom in which LiF thermoluminescent dosimeters were arranged along the spiral trajectory. The maximum difference between the predicted and measured TLD data for the 1.8 Gy fraction was 0.06 Gy for a TLD located in a high dose gradient region. This further validates the ability of the spiral phantom QA process to accurately verify delivery of an IMRT plan

  19. Emergency repair of severely damaged reinforced concrete columns using active confinement with shape memory alloys

    International Nuclear Information System (INIS)

    Shin, Moochul; Andrawes, Bassem

    2011-01-01

    This experimental study focuses on investigating the feasibility of utilizing spirals made of shape memory alloys (SMAs) to conduct emergency repair on severely damaged reinforced concrete (RC) columns. The thermally triggered shape memory feature of SMAs is sought in this study, to apply active confinement pressure on the column's damaged region. Two severely damaged 1/3-scale RC columns are repaired using the proposed technique and tested under a quasi-static lateral cyclic load. The repair of each column is conducted in less than 15 h, and the columns are tested 24 h after the starting of the repair process. The experimental results show that the new repair technique is successful in either fully restoring the as-built lateral strength, stiffness, and flexural ductility of the columns or making them even better. The efficacy of the proposed repair technique is mainly attributed to the ability of the SMA spirals to apply and maintain active confining pressure on the damaged region of the columns, which increases the strength of the already damaged concrete and delays its damage

  20. Assembly for connecting the column ends of two capillary columns

    International Nuclear Information System (INIS)

    Kolb, B.; Auer, M.; Pospisil, P.

    1984-01-01

    In gas chromatography, the column ends of two capillary columns are inserted into a straight capillary from both sides forming annular gaps. The capillary is located in a tee out of which the capillary columns are sealingly guided, and to which carrier gas is supplied by means of a flushing flow conduit. A ''straight-forward operation'' having capillary columns connected in series and a ''flush-back operation'' are possible. The dead volume between the capillary columns can be kept small

  1. Software configuration management

    International Nuclear Information System (INIS)

    Arribas Peces, E.; Martin Faraldo, P.

    1993-01-01

    Software Configuration Management is directed towards identifying system configuration at specific points of its life cycle, so as to control changes to the configuration and to maintain the integrity and traceability of the configuration throughout its life. SCM functions and tasks are presented in the paper

  2. Optical analysis of dust complexes in spiral galaxies

    International Nuclear Information System (INIS)

    Elmegreen, D.A.M.

    1979-01-01

    A method for quantitatively investigating properties of dust regions in external galaxies is presented. The technique involves matching radiative transfer models (with absorption plus scattering) to multicolor photographic and photometric observations. Dust features in each galaxy are modeled with two configurations; one is rectangular with a Gaussian distribution perpendicular to the plane of the galaxy, and the other is a uniform oblate spheroid with an arbitrary height from the midplane. It is found that it is possible to determine the intrinsic opacities in the clouds and in the nearby comparison regions, and that differention between high opacity low-lying clouds and low opacity clouds that are above the midplane can be made. This technique was used to study dust complexes in the late-type spiral galaxies NGC 628 (M74), NGC 5194 (M51), NGC 5457 (M101), and NGC 7793. Most of the features in the prominent dust lanes were found to have internal visual extinctions corresponding to 10 to 15 mag kpc -1 , while the adjacent comparison regions typically contained 4 mag kpc -1 . Thus the opacity through a dust lane is about 1.5 mag greater than the 0.5 to 1.0 mag of extinction through a comparison region. A noticeable deviation from this result was found for all of the dust lanes that occurred on the inner edges of the spiral arm branches. These features had internal densities that were approx. 10 times larger than in their comparison regions, in contrast to the normal dust lanes which had density enhancements of a factor of approx. 3. Dust features which were on the outer sides of spiral arms appeared to be no different than main inner dust lane features

  3. Echo-Interleaved-Spiral MR Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, Shirrie; Azhari, Haim [Department of Biomedical Engineering, Technion, Israel Institute of Technology, Haifa 32000 (Israel); Montag, Avram [Elscint Ltd., MRI division, Haifa (Israel)

    1999-12-31

    Interleaved-Spiral imaging is an efficient method for MRI fast scans. However, images suffer from blurring and artifacts due to field inhomogeneities and the long readout times. In this paper, we combine interleaved-spirals with spin-echo for 3D scans. The refocusing RF-pulses (echoes) refocus off-resonance spins, thus allowing longer acquisition times per excitation, by limiting inhomogeneity effects. The total number of excitations for a 3D scan is reduced by half. The 3D Fourier transform of an object is divided into pairs of slices, one slice is scanned in an outgoing interleaved-spiral, initiated after a 90 degree pulse has been applied. The second slice is scanned in an ingoing interleaved-spiral, after a 180 degree pulse has been applied, thus reaching the slice origin at the echo time. (authors) 4 refs., 3 figs.

  4. Echo-Interleaved-Spiral MR Imaging

    International Nuclear Information System (INIS)

    Rosenthal, Shirrie; Azhari, Haim; Montag, Avram

    1998-01-01

    Interleaved-Spiral imaging is an efficient method for MRI fast scans. However, images suffer from blurring and artifacts due to field inhomogeneities and the long readout times. In this paper, we combine interleaved-spirals with spin-echo for 3D scans. The refocusing RF-pulses (echoes) refocus off-resonance spins, thus allowing longer acquisition times per excitation, by limiting inhomogeneity effects. The total number of excitations for a 3D scan is reduced by half. The 3D Fourier transform of an object is divided into pairs of slices, one slice is scanned in an outgoing interleaved-spiral, initiated after a 90 degree pulse has been applied. The second slice is scanned in an ingoing interleaved-spiral, after a 180 degree pulse has been applied, thus reaching the slice origin at the echo time. (authors)

  5. Corrosion of Spiral Rib Aluminized Pipe : [Summary

    Science.gov (United States)

    2012-01-01

    Large diameter, corrugated steel pipes are a common sight in the culverts that run alongside many Florida roads. Spiral-ribbed aluminized pipe (SRAP) has been widely specified by the Florida Department of Transportation (FDOT) for runoff drainage. Th...

  6. Corrosion of Spiral Rib Aluminized Pipe

    Science.gov (United States)

    2012-08-01

    Large diameter, corrugated steel pipes are a common sight in the culverts that run alongside many Florida roads. Spiral-ribbed aluminized pipe (SRAP) has been widely specified by the Florida Department of Transportation (FDOT) for runoff drainage. Th...

  7. Pulsatile spiral blood flow through arterial stenosis.

    Science.gov (United States)

    Linge, Fabian; Hye, Md Abdul; Paul, Manosh C

    2014-11-01

    Pulsatile spiral blood flow in a modelled three-dimensional arterial stenosis, with a 75% cross-sectional area reduction, is investigated by using numerical fluid dynamics. Two-equation k-ω model is used for the simulation of the transitional flow with Reynolds numbers 500 and 1000. It is found that the spiral component increases the static pressure in the vessel during the deceleration phase of the flow pulse. In addition, the spiral component reduces the turbulence intensity and wall shear stress found in the post-stenosis region of the vessel in the early stages of the flow pulse. Hence, the findings agree with the results of Stonebridge et al. (2004). In addition, the results of the effects of a spiral component on time-varying flow are presented and discussed along with the relevant pathological issues.

  8. Magnetic spiral arms in galaxy haloes

    Science.gov (United States)

    Henriksen, R. N.

    2017-08-01

    We seek the conditions for a steady mean field galactic dynamo. The parameter set is reduced to those appearing in the α2 and α/ω dynamo, namely velocity amplitudes, and the ratio of sub-scale helicity to diffusivity. The parameters can be allowed to vary on conical spirals. We analyse the mean field dynamo equations in terms of scale invariant logarithmic spiral modes and special exact solutions. Compatible scale invariant gravitational spiral arms are introduced and illustrated in an appendix, but the detailed dynamical interaction with the magnetic field is left for another work. As a result of planar magnetic spirals `lifting' into the halo, multiple sign changes in average rotation measures forming a regular pattern on each side of the galactic minor axis, are predicted. Such changes have recently been detected in the Continuum Halos in Nearby Galaxies-an EVLA Survey (CHANG-ES) survey.

  9. Conceptualizing Embedded Configuration

    DEFF Research Database (Denmark)

    Oddsson, Gudmundur Valur; Hvam, Lars; Lysgaard, Ole

    2006-01-01

    and services. The general idea can be named embedded configuration. In this article we intend to conceptualize embedded configuration, what it is and is not. The difference between embedded configuration, sales configuration and embedded software is explained. We will look at what is needed to make embedded...... configuration systems. That will include requirements to product modelling techniques. An example with consumer electronics will illuminate the elements of embedded configuration in settings that most can relate to. The question of where embedded configuration would be relevant is discussed, and the current...

  10. Columns in Clay

    Science.gov (United States)

    Leenhouts, Robin

    2010-01-01

    This article describes a clay project for students studying Greece and Rome. It provides a wonderful way to learn slab construction techniques by making small clay column capitols. With this lesson, students learn architectural vocabulary and history, understand the importance of classical architectural forms and their influence on today's…

  11. Slender CRC Columns

    DEFF Research Database (Denmark)

    Aarup, Bendt; Jensen, Lars Rom; Ellegaard, Peter

    2005-01-01

    CRC is a high-performance steel fibre reinforced concrete with a typical compressive strength of 150 MPa. Design methods for a number of structural elements have been developed since CRC was invented in 1986, but the current project set out to further investigate the range of columns for which...

  12. Practical column design guide

    CERN Document Server

    Nitsche, M

    2017-01-01

    This book highlights the aspects that need to be considered when designing distillation columns in practice. It discusses the influencing parameters as well as the equations governing them, and presents several numerical examples. The book is intended both for experienced designers and for those who are new to the subject.

  13. Statistical analysis of metallicity in spiral galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Galeotti, P [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Turin Univ. (Italy). Ist. di Fisica Generale)

    1981-04-01

    A principal component analysis of metallicity and other integral properties of 33 spiral galaxies is presented; the involved parameters are: morphological type, diameter, luminosity and metallicity. From the statistical analysis it is concluded that the sample has only two significant dimensions and additonal tests, involving different parameters, show similar results. Thus it seems that only type and luminosity are independent variables, being the other integral properties of spiral galaxies correlated with them.

  14. Galactic models with variable spiral structure

    International Nuclear Information System (INIS)

    James, R.A.; Sellwood, J.A.

    1978-01-01

    A series of three-dimensional computer simulations of disc galaxies has been run in which the self-consistent potential of the disc stars is supplemented by that arising from a small uniform Population II sphere. The models show variable spiral structure, which is more pronounced for thin discs. In addition, the thin discs form weak bars. In one case variable spiral structure associated with this bar has been seen. The relaxed discs are cool outside resonance regions. (author)

  15. Control structure selection for energy integrated distillation column

    DEFF Research Database (Denmark)

    Hansen, J.E.; Jørgensen, Sten Bay

    1998-01-01

    This paper treats a case study on control structure selection for an almost binary distillation column. The column is energy integrated with a heat pump in order to transfer heat from the condenser to the reboiler. This integrated plant configuration renders the possible control structures somewhat...... different from what is usual for binary distillation columns. Further the heat pump enables disturbances to propagate faster through the system. The plant has six possible actuators of which three must be used to stabilize the system. Hereby three actuators are left for product purity control. An MILP...

  16. Heat Transfer Analysis for a Fixed CST Column

    International Nuclear Information System (INIS)

    Lee, S.Y.

    2004-01-01

    In support of a small column ion exchange (SCIX) process for the Savannah River Site waste processing program, a transient two-dimensional heat transfer model that includes the conduction process neglecting the convection cooling mechanism inside the crystalline silicotitanate (CST) column has been constructed and heat transfer calculations made for the present design configurations. For this situation, a no process flow condition through the column was assumed as one of the reference conditions for the simulation of a loss-of-flow accident. A series of the modeling calculations has been performed using a computational heat transfer approach. Results for the baseline model indicate that transit times to reach 130 degrees Celsius maximum temperature of the CST-salt solution column are about 96 hours when the 20-in CST column with 300 Ci/liter heat generation source and 25 degrees Celsius initial column temperature is cooled by natural convection of external air as a primary heat transfer mechanism. The modeling results for the 28-in column equipped with water jacket systems on the external wall surface of the column and water coolant pipe at the center of the CST column demonstrate that the column loaded with 300 Ci/liter heat source can be maintained non-boiling indefinitely. Sensitivity calculations for several alternate column sizes, heat loads of the packed column, engineered cooling systems, and various ambient conditions at the exterior wall of the column have been performed under the reference conditions of the CST-salt solution to assess the impact of those parameters on the peak temperatures of the packed column for a given transient time. The results indicate that a water-coolant pipe at the center of the CST column filled with salt solution is the most effective one among the potential design parameters related to the thermal energy dissipation of decay heat load. It is noted that the cooling mechanism at the wall boundary of the column has significant

  17. SIGNATURES OF LONG-LIVED SPIRAL PATTERNS

    International Nuclear Information System (INIS)

    Martínez-García, Eric E.; González-Lópezlira, Rosa A.

    2013-01-01

    Azimuthal age/color gradients across spiral arms are a signature of long-lived spirals. From a sample of 19 normal (or weakly barred) spirals where we have previously found azimuthal age/color gradient candidates, 13 objects were further selected if a two-armed grand-design pattern survived in a surface density stellar mass map. Mass maps were obtained from optical and near-infrared imaging, by comparison with a Monte Carlo library of stellar population synthesis models that allowed us to obtain the mass-to-light ratio in the J band, (M/L) J , as a function of (g – i) versus (i – J) color. The selected spirals were analyzed with Fourier methods in search of other signatures of long-lived modes related to the gradients, such as the gradient divergence toward corotation, and the behavior of the phase angle of the two-armed spiral in different wavebands, as expected from theory. The results show additional signatures of long-lived spirals in at least 50% of the objects.

  18. Chiralities of spiral waves and their transitions.

    Science.gov (United States)

    Pan, Jun-ting; Cai, Mei-chun; Li, Bing-wei; Zhang, Hong

    2013-06-01

    The chiralities of spiral waves usually refer to their rotation directions (the turning orientations of the spiral temporal movements as time elapses) and their curl directions (the winding orientations of the spiral spatial geometrical structures themselves). Traditionally, they are the same as each other. Namely, they are both clockwise or both counterclockwise. Moreover, the chiralities are determined by the topological charges of spiral waves, and thus they are conserved quantities. After the inwardly propagating spirals were experimentally observed, the relationship between the chiralities and the one between the chiralities and the topological charges are no longer preserved. The chiralities thus become more complex than ever before. As a result, there is now a desire to further study them. In this paper, the chiralities and their transition properties for all kinds of spiral waves are systemically studied in the framework of the complex Ginzburg-Landau equation, and the general relationships both between the chiralities and between the chiralities and the topological charges are obtained. The investigation of some other models, such as the FitzHugh-Nagumo model, the nonuniform Oregonator model, the modified standard model, etc., is also discussed for comparison.

  19. Spiral 2: preliminary design study

    International Nuclear Information System (INIS)

    2001-11-01

    The scientific council of GANIL asked to perform a comparative study on the production methods based on gamma induced fission and rapid-neutron induced fission concerning the nature and the intensity of the neutron-rich products. The production rate expected should be around 10 13 fissions per second. The study should include the implantation and the costs of the concerned accelerators. The scientific committee recommended also to study the possibility to re-inject the radioactive beams of SPIRAL-II in the cyclotrons available at GANIL in order to give access to an energy range from 1.7 to 100 MeV/nucleon. For that purpose, some study groups have been formed to evaluate the possibility of such a project in the different components: physics case, target-ion sources, drivers, post-acceleration and general infrastructure. The organization of the project study is given at the end of this report. The following report presents an overview of the study. Particularly the total costs have been assessed according to 3 options for the driver: 38.0*10 6 euros for a 40 MeV deuteron linac, 18.7*10 6 euros for a 45 MeV electron linac, and 29.1*10 6 euros for a 80 MeV deuteron cyclotron

  20. Spiral 2: preliminary design study

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-11-15

    The scientific council of GANIL asked to perform a comparative study on the production methods based on gamma induced fission and rapid-neutron induced fission concerning the nature and the intensity of the neutron-rich products. The production rate expected should be around 10{sup 13} fissions per second. The study should include the implantation and the costs of the concerned accelerators. The scientific committee recommended also to study the possibility to re-inject the radioactive beams of SPIRAL-II in the cyclotrons available at GANIL in order to give access to an energy range from 1.7 to 100 MeV/nucleon. For that purpose, some study groups have been formed to evaluate the possibility of such a project in the different components: physics case, target-ion sources, drivers, post-acceleration and general infrastructure. The organization of the project study is given at the end of this report. The following report presents an overview of the study. Particularly the total costs have been assessed according to 3 options for the driver: 38.0*10{sup 6} euros for a 40 MeV deuteron linac, 18.7*10{sup 6} euros for a 45 MeV electron linac, and 29.1*10{sup 6} euros for a 80 MeV deuteron cyclotron.

  1. Dark matter in spiral galaxies

    International Nuclear Information System (INIS)

    Albada, T.S. van; Sancisi, R.

    1986-01-01

    Mass models of spiral galaxies based on the observed light distribution, assuming constant M/L for bulge and disc, are able to reproduce the observed rotation curves in the inner regions, but fail to do so increasingly towards and beyond the edge of the visible material. The discrepancy in the outer region can be accounted for by invoking dark matter; some galaxies require at least four times as much dark matter as luminous matter. There is no evidence for a dependence on galaxy luminosity or morphological type. Various arguments support the idea that a distribution of visible matter with constant M/L is responsible for the circular velocity in the inner region, i.e. inside approximately 2.5 disc scalelengths. Luminous matter and dark matter seem to 'conspire' to produce the flat observed rotation curves in the outer region. It seems unlikely that this coupling between disc and halo results from the large-scale gravitational interaction between the two components. Attempts to determine the shape of dark halos have not yet produced convincing results. (author)

  2. Six Decades of Spiral Density Wave Theory

    Science.gov (United States)

    Shu, Frank H.

    2016-09-01

    The theory of spiral density waves had its origin approximately six decades ago in an attempt to reconcile the winding dilemma of material spiral arms in flattened disk galaxies. We begin with the earliest calculations of linear and nonlinear spiral density waves in disk galaxies, in which the hypothesis of quasi-stationary spiral structure (QSSS) plays a central role. The earliest success was the prediction of the nonlinear compression of the interstellar medium and its embedded magnetic field; the earliest failure, seemingly, was not detecting color gradients associated with the migration of OB stars whose formation is triggered downstream from the spiral shock front. We give the reasons for this apparent failure with an update on the current status of the problem of OB star formation, including its relationship to the feathering substructure of galactic spiral arms. Infrared images can show two-armed, grand design spirals, even when the optical and UV images show flocculent structures. We suggest how the nonlinear response of the interstellar gas, coupled with overlapping subharmonic resonances, might introduce chaotic behavior in the dynamics of the interstellar medium and Population I objects, even though the underlying forces to which they are subject are regular. We then move to a discussion of resonantly forced spiral density waves in a planetary ring and their relationship to the ideas of disk truncation, and the shepherding of narrow rings by satellites orbiting nearby. The back reaction of the rings on the satellites led to the prediction of planet migration in protoplanetary disks, which has had widespread application in the exploding data sets concerning hot Jupiters and extrasolar planetary systems. We then return to the issue of global normal modes in the stellar disk of spiral galaxies and its relationship to the QSSS hypothesis, where the central theoretical concepts involve waves with negative and positive surface densities of energy and angular

  3. Nine Words - Nine Columns

    DEFF Research Database (Denmark)

    Trempe Jr., Robert B.; Buthke, Jan

    2016-01-01

    This book records the efforts of a one-week joint workshop between Master students from Studio 2B of Arkitektskolen Aarhus and Master students from the Harbin Institute of Technology in Harbin, China. The workshop employed nine action words to instigate team-based investigation into the effects o...... as formwork for the shaping of wood veneer. The resulting columns ‘wear’ every aspect of this design pipeline process and display the power of process towards an architectural resolution....

  4. HEAT TRANSFER ANALYSIS FOR FIXED CST AND RF COLUMNS

    International Nuclear Information System (INIS)

    Lee, S

    2007-01-01

    temperature with either ion exchange material. Sensitivity calculations for the RF resin porosity, the ambient external column temperature, and the cooling system configuration were performed under the baseline conditions to assess the impact of these parameters on the maximum temperatures. It is noted that the cooling mechanism at the column boundary (forced versus natural convection) and the cooling system configuration significantly impact the maximum temperatures. The analysis results provide quantitative information associated with process temperature control requirements and management of the SCIX column

  5. A unix configuration engine

    International Nuclear Information System (INIS)

    Burgess, M.

    1994-06-01

    A high level description language is presented for the purpose of automatically configuring large heterogeneous networked unix environments, based on class-oriented abstractions. The configuration engine is portable and easily extensible

  6. NMFS Water Column Sonar Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water column sonar data are an important component of fishery independent surveys, habitat studies and other research. NMFS water column sonar data are archived here.

  7. MICROCONTROLLER PIN CONFIGURATION TOOL

    OpenAIRE

    Bhaskar Joshi; F. Mohammed Rizwan; Dr. Rajashree Shettar

    2012-01-01

    Configuring the micro controller with large number of pins is tedious. Latest Infine on microcontroller contains more than 200 pins and each pin has classes of signals. Therefore the complexity of the microcontroller is growing. It evolves looking into thousands of pages of user manual. For a user it will take days to configure the microcontroller with the peripherals. We need an automated tool to configure the microcontroller so that the user can configure the microcontroller without having ...

  8. Operational Dynamic Configuration Analysis

    Science.gov (United States)

    Lai, Chok Fung; Zelinski, Shannon

    2010-01-01

    Sectors may combine or split within areas of specialization in response to changing traffic patterns. This method of managing capacity and controller workload could be made more flexible by dynamically modifying sector boundaries. Much work has been done on methods for dynamically creating new sector boundaries [1-5]. Many assessments of dynamic configuration methods assume the current day baseline configuration remains fixed [6-7]. A challenging question is how to select a dynamic configuration baseline to assess potential benefits of proposed dynamic configuration concepts. Bloem used operational sector reconfigurations as a baseline [8]. The main difficulty is that operational reconfiguration data is noisy. Reconfigurations often occur frequently to accommodate staff training or breaks, or to complete a more complicated reconfiguration through a rapid sequence of simpler reconfigurations. Gupta quantified a few aspects of airspace boundary changes from this data [9]. Most of these metrics are unique to sector combining operations and not applicable to more flexible dynamic configuration concepts. To better understand what sort of reconfigurations are acceptable or beneficial, more configuration change metrics should be developed and their distribution in current practice should be computed. This paper proposes a method to select a simple sequence of configurations among operational configurations to serve as a dynamic configuration baseline for future dynamic configuration concept assessments. New configuration change metrics are applied to the operational data to establish current day thresholds for these metrics. These thresholds are then corroborated, refined, or dismissed based on airspace practitioner feedback. The dynamic configuration baseline selection method uses a k-means clustering algorithm to select the sequence of configurations and trigger times from a given day of operational sector combination data. The clustering algorithm selects a simplified

  9. Investigation of logarithmic spiral nanoantennas at optical frequencies

    Science.gov (United States)

    Verma, Anamika; Pandey, Awanish; Mishra, Vigyanshu; Singh, Ten; Alam, Aftab; Dinesh Kumar, V.

    2013-12-01

    The first study is reported of a logarithmic spiral antenna in the optical frequency range. Using the finite integration technique, we investigated the spectral and radiation properties of a logarithmic spiral nanoantenna and a complementary structure made of thin gold film. A comparison is made with results for an Archimedean spiral nanoantenna. Such nanoantennas can exhibit broadband behavior that is independent of polarization. Two prominent features of logarithmic spiral nanoantennas are highly directional far field emission and perfectly circularly polarized radiation when excited by a linearly polarized source. The logarithmic spiral nanoantenna promises potential advantages over Archimedean spirals and could be harnessed for several applications in nanophotonics and allied areas.

  10. Galaxy Zoo: dust in spiral galaxies

    Science.gov (United States)

    Masters, Karen L.; Nichol, Robert; Bamford, Steven; Mosleh, Moein; Lintott, Chris J.; Andreescu, Dan; Edmondson, Edward M.; Keel, William C.; Murray, Phil; Raddick, M. Jordan; Schawinski, Kevin; Slosar, Anže; Szalay, Alexander S.; Thomas, Daniel; Vandenberg, Jan

    2010-05-01

    We investigate the effect of dust on spiral galaxies by measuring the inclination dependence of optical colours for 24276 well-resolved Sloan Digital Sky Survey (SDSS) galaxies visually classified via the Galaxy Zoo project. We find clear trends of reddening with inclination which imply a total extinction from face-on to edge-on of 0.7, 0.6, 0.5 and 0.4mag for the ugri passbands (estimating 0.3mag of extinction in z band). We split the sample into `bulgy' (early-type) and `discy' (late-type) spirals using the SDSS fracdeV (or fDeV) parameter and show that the average face-on colour of `bulgy' spirals is redder than the average edge-on colour of `discy' spirals. This shows that the observed optical colour of a spiral galaxy is determined almost equally by the spiral type (via the bulge-disc ratio and stellar populations), and reddening due to dust. We find that both luminosity and spiral type affect the total amount of extinction, with discy spirals at Mr ~ -21.5mag having the most reddening - more than twice as much as both the lowest luminosity and most massive, bulge-dominated spirals. An increase in dust content is well known for more luminous galaxies, but the decrease of the trend for the most luminous has not been observed before and may be related to their lower levels of recent star formation. We compare our results with the latest dust attenuation models of Tuffs et al. We find that the model reproduces the observed trends reasonably well but overpredicts the amount of u-band attenuation in edge-on galaxies. This could be an inadequacy in the Milky Way extinction law (when applied to external galaxies), but more likely indicates the need for a wider range of dust-star geometries. We end by discussing the effects of dust on large galaxy surveys and emphasize that these effects will become important as we push to higher precision measurements of galaxy properties and their clustering. This publication has been made possible by the participation of more than

  11. Analysis of spiral components in 16 galaxies

    International Nuclear Information System (INIS)

    Considere, S.; Athanassoula, E.

    1988-01-01

    A Fourier analysis of the intensity distributions in the plane of 16 spiral galaxies of morphological types from 1 to 7 is performed. The galaxies processed are NGC 300,598,628,2403,2841,3031,3198,3344,5033,5055,5194,5247,6946,7096,7217, and 7331. The method, mathematically based upon a decomposition of a distribution into a superposition of individual logarithmic spiral components, is first used to determine for each galaxy the position angle PA and the inclination ω of the galaxy plane onto the sky plane. Our results, in good agreement with those issued from different usual methods in the literature, are discussed. The decomposition of the deprojected galaxies into individual spiral components reveals that the two-armed component is everywhere dominant. Our pitch angles are then compared to the previously published ones and their quality is checked by drawing each individual logarithmic spiral on the actual deprojected galaxy images. Finally, the surface intensities for angular periodicities of interest are calculated. A choice of a few of the most important ones is used to elaborate a composite image well representing the main spiral features observed in the deprojected galaxies

  12. The design and basic performance of a Spiral Fiber Tracker for the J-PARC E36 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mineev, O., E-mail: oleg@inr.ru [Institute for Nuclear Research of RAS, Moscow (Russian Federation); Bianchin, S. [Canada' s National Laboratory for Particle and Nuclear Physics (TRIUMF) (Canada); Hasinoff, M.D. [University of British Columbia (Canada); Horie, K. [Osaka University (Japan); Igarashi, Y.; Imazato, J. [High Energy Accelerator Research Organization (KEK) (Japan); Ito, H.; Kawai, H.; Kodama, S. [Chiba University (Japan); Kohl, M. [Hampton University (United States); Kudenko, Yu. [Institute for Nuclear Research of RAS, Moscow (Russian Federation); National Research Nuclear University MEPhI, Moscow (Russian Federation); Moscow Institute of Physics and Technology (Russian Federation); Shimizu, S. [Osaka University (Japan); Tabata, M. [Chiba University (Japan); Toyoda, A. [High Energy Accelerator Research Organization (KEK) (Japan); Yershov, N. [Institute for Nuclear Research of RAS, Moscow (Russian Federation)

    2017-03-01

    A spiral fiber tracker (SFT) has been designed and produced for the J-PARC E36 experiment as an element of the tracking system for conducting a high-resolution momentum measurement of charged particles from kaon decays. A novel technique to wind the pre-made fiber ribbons spirally was employed for the configuration with four detector layers made of 1 mm diameter plastic scintillating fibers. Good position alignment and sufficiently high detection efficiency for charged particles with minimum ionizing energy were confirmed in cosmic ray test. The tracker was successfully used in the E36 experiment.

  13. Design of interdigital spiral and concentric capacitive sensors for materials evaluation

    Science.gov (United States)

    Chen, Tianming; Bowler, Nicola

    2013-01-01

    This paper describes the design of two circular coplanar interdigital sensors with i) a spiral interdigital configuration and ii) a concentric interdigital configuration for the nondestructive evaluation of multilayered dielectric structures. A numerical model accounting for sensor geometry, test-piece geometry and real permittivity, and metal electrode thickness has been developed to calculate the capacitance of the sensors when in contact with a planar test-piece comprising up to four layers. Compared with a disk-and-ring coplanar capacitive sensor developed previously, the interdigital configurations are predicted to have higher signal-to-noise ratio and better accuracy in materials characterization. The disk-and-ring configuration, on the other hand, possesses advantages such as deeper penetration depth and better immunity to lift-off variations.

  14. Large-scale filaments associated with Milky Way spiral arms

    Science.gov (United States)

    Wang, Ke; Testi, Leonardo; Ginsburg, Adam; Walmsley, C. Malcolm; Molinari, Sergio; Schisano, Eugenio

    2015-07-01

    The ubiquity of filamentary structure at various scales throughout the Galaxy has triggered a renewed interest in their formation, evolution, and role in star formation. The largest filaments can reach up to Galactic scale as part of the spiral arm structure. However, such large-scale filaments are hard to identify systematically due to limitations in identifying methodology (i.e. as extinction features). We present a new approach to directly search for the largest, coldest, and densest filaments in the Galaxy, making use of sensitive Herschel Hi-GAL (Herschel Infrared Galactic Plane Survey) data complemented by spectral line cubes. We present a sample of the nine most prominent Herschel filaments, including six identified from a pilot search field plus three from outside the field. These filaments measure 37-99 pc long and 0.6-3.0 pc wide with masses (0.5-8.3) × 104 M⊙, and beam-averaged (28 arcsec, or 0.4-0.7 pc) peak H2 column densities of (1.7-9.3)× 1022 cm- 2. The bulk of the filaments are relatively cold (17-21 K), while some local clumps have a dust temperature up to 25-47 K. All the filaments are located within ≲60 pc from the Galactic mid-plane. Comparing the filaments to a recent spiral arm model incorporating the latest parallax measurements, we find that 7/9 of them reside within arms, but most are close to arm edges. These filaments are comparable in length to the Galactic scaleheight and therefore are not simply part of a grander turbulent cascade.

  15. Integrity of Bolted Angle Connections Subjected to Simulated Column Removal

    Science.gov (United States)

    Weigand, Jonathan M.; Berman, Jeffrey W.

    2016-01-01

    Large-scale tests of steel gravity framing systems (SGFSs) have shown that the connections are critical to the system integrity, when a column suffers damage that compromises its ability to carry gravity loads. When supporting columns were removed, the SGFSs redistributed gravity loads through the development of an alternate load path in a sustained tensile configuration resulting from large vertical deflections. The ability of the system to sustain such an alternate load path depends on the capacity of the gravity connections to remain intact after undergoing large rotation and axial extension demands, for which they were not designed. This study experimentally evaluates the performance of steel bolted angle connections subjected to loading consistent with an interior column removal. The characteristic connection behaviors are described and the performance of multiple connection configurations are compared in terms of their peak resistances and deformation capacities. PMID:27110059

  16. Sharp corners as sources of spiral pairs

    International Nuclear Information System (INIS)

    Biton, Y.; Rabinovitch, A.; Braunstein, D.; Friedman, M.; Aviram, I.

    2010-01-01

    It is demonstrated that using the FitzHugh-Nagumo model, stimulation of excitable media inside a region possessing sharp corners, can lead to the appearance of sources of spiral-pairs of sustained activity. The two conditions for such source creation are: The corners should be less than 120 deg. and the range of stimulating amplitudes should be small, occurring just above the threshold value and decreasing with the corner angle. The basic mechanisms driving the phenomenon are discussed. These include: A. If the corner angle is below 120 deg., the wave generated inside cannot emerge at the corner tip, resulting in the creation of two free edges which start spiraling towards each other. B. Spiraling must be strong enough; otherwise annihilation of the rotating arms would occur too soon to create a viable source. C. The intricacies of the different radii involved are elucidated. Possible applications in heart stimulation and in chemical reactions are considered.

  17. Principles of spiral CT: III. Quality assurance

    International Nuclear Information System (INIS)

    Suess, C.; Kalender, W.A.

    1998-01-01

    Since its introduction in 1989 spiral CT has gained wide clinical acceptance and meanwhile it covers a large range of CT applications. This new technology, however, has not yet been recognized and acknowledged in the national or international regulations on scanner quality assurance (QA) programs. The conventional QA procedures should be extended to check the distribution of resolution and noise within the image plane. Imaging performance in the axial direction constitutes one of the major advantages of spiral scanning. Therefore, the slice sensitivity profiles and the spatial and low-contrast resolution along the z-axis have to be assessed. The high demands on table feed accuracy require additional tests. We suggest phantoms and procedures to check and quantify these parameters. Thereby, we hope to support the ongoing discussion about spiral CT quality assurance. (orig.) [de

  18. Spiral loaded cavities for heavy ion acceleration

    International Nuclear Information System (INIS)

    Schempp, A.; Klein, H.

    1976-01-01

    A transmission line theory of the spiral resonator has been performed and the calculated and measured properties will be compared. Shunt impedances up to 50 MΩ/m have been measured. In a number of high power tests the structure has been tested and its electrical and mechanical stability has been investigated. The static frequency shift due to ponderomotoric forces was between 0.2 and 50 kHz/kW dependent on the geometrical parameters of the spirals. The maximum field strength obtained on the axis was 16 MV/m in pulsed operation and 9.2 MV/m in cw, corresponding to a voltage gain per cavity of up to 0.96 MV. The results show that spiral resonators are well suited as heavy ion accelerator cavities. (author)

  19. Organic carbon spiralling in stream ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Newbold, J D; Mulholland, P J; Elwood, J W; O' Neill, R V

    1982-01-01

    The term spiralling has been used to describe the combined processes of cycling and longitudinal transport in streams. As a measure or organic carbon spiralling, we introduced organic carbon turnover length, S, defined as the average or expected downstream distance travelled by a carbon atom between its entry or fixation in the stream and its oxidation. Using a simple model for organic carbon dynamics in a stream, we show that S is closely related to fisher and Likens' ecosystem efficiency. Unlike efficiency, however, S is independent of the length of the study reach, and values of S determined in streams of differing lengths can be compared. Using data from three different streams, we found the relationship between S and efficiency to agree closely with the model prediction. Hypotheses of stream functioning are discussed in the context of organic carbeon spiralling theory.

  20. Spiral arms, comets and terrestrial catastrophism

    International Nuclear Information System (INIS)

    Clube, S.V.M.; Napier, W.M.

    1982-01-01

    A review is presented of an hypothesis of terrestrial catastrophism in which comets grow in molecular clouds and are captured by the Sun as it passes through the spiral arms of the Galaxy. Assuming that comets are a major supplier of the Earth-crossing (Appollo) asteroid population, the latter fluctuates correspondingly and leads to episodes of terrestrial bombardment. Changes in the rotational momentum of core and mantle, generated by impacts, lead to episodes of magnetic field reversal and tectonic activity, while surface phenomena lead to ice-ages and mass extinctions. An episodic geophysical history with an interstellar connection is thus implied. If comets in spiral arms are necessary intermediaries in the process of star formation, the theory also has implications relating to early solar system history and galactic chemistry. These aspects are briefly discussed with special reference to the nature of spiral arms. (author)

  1. Molecular clouds and galactic spiral structure

    International Nuclear Information System (INIS)

    Dame, T.M.

    1984-02-01

    Galactic CO line emission at 115 GHz was surveyed in order to study the distribution of molecular clouds in the inner galaxy. Comparison of this survey with similar H1 data reveals a detailed correlation with the most intense 21 cm features. To each of the classical 21 cm H1 spiral arms of the inner galaxy there corresponds a CO molecular arm which is generally more clearly defined and of higher contrast. A simple model is devised for the galactic distribution of molecular clouds. The modeling results suggest that molecular clouds are essentially transient objects, existing for 15 to 40 million years after their formation in a spiral arm, and are largely confined to spiral features about 300 pc wide

  2. Spiral CT manifestations of spherical pneumonia

    International Nuclear Information System (INIS)

    Li Xiaohong; Yang Hongwei; Xu Chunmin; Qin Xiu

    2008-01-01

    Objective: To explore the Spiral CT manifestations and differential diagnosis of spherical pneumonia. Methods: 18 cases of spherical pneumonia and 20 cases of peripheral pulmonary carcinoma were selected, both of them were confirmed by clinic and/or pathology. The SCT findings of both groups were compared retrospectively. Results: Main spiral CT findings of spherical pneumonia were showed as followings: square or triangular lesions adjacent to pleura; with irregular shape, blurry, slightly lobulated margin, sometimes with halo sign. Small inflammatory patches and intensified vascular markings around the lesions were seen. Lesions became smaller or vanished after short-term anti-inflammatory treatment. Conclusion: Spherical pneumonia showed some characteristics on Spiral CT scan, which are helpful in diagnosis and differential diagnosis of this disease. (authors)

  3. Spiral CT for evaluation of chest trauma

    International Nuclear Information System (INIS)

    Roehnert, W.; Weise, R.

    1997-01-01

    After implementation of spiral CT in our department, we carried out an analysis for determining anew the value of CT as a modality of chest trauma diagnosis in the emergency department. The retrospective study covers a period of 10 months and all emergency patients with chest trauma exmined by spiral CT. The major lesions of varying seriousness covered by this study are: pneumothorax, hematothorax, pulmonary contusion or laceration, mediastinal hematoma, rupture of a vessel, injury of the heart and pericardium. The various fractures are not included in this study. In many cases, spiral CT within relatively short time yields significant diagnostic findings, frequently saving additional angiography. A rigid diagnostic procedure cannot be formulated. Plain-film chest radiography still remains a diagnostic modality of high value. (Orig.) [de

  4. HLT configuration management system

    CERN Document Server

    Daponte, Vincenzo

    2015-01-01

    The CMS High Level Trigger (HLT) is implemented running a streamlined version of the CMS offline reconstruction software running on thousands of CPUs. The CMS software is written mostly in C++, using Python as its configuration language through an embedded CPython interpreter. The configuration of each process is made up of hundreds of modules, organized in sequences and paths. As an example, the HLT configurations used for 2011 data taking comprised over 2200 different modules, organized in more than 400 independent trigger paths. The complexity of the HLT configurations and the large number of configuration produced require the design of a suitable data management system. The present work describes the designed solution to manage the considerable number of configurations developed and to assist the editing of new configurations. The system is required to be remotely accessible and OS-independent as well as easly maintainable easy to use. To meet these requirements a three-layers architecture has been choose...

  5. Simulations of the flocculent spiral M33: what drives the spiral structure?

    Science.gov (United States)

    Dobbs, C. L.; Pettitt, A. R.; Corbelli, E.; Pringle, J. E.

    2018-05-01

    We perform simulations of isolated galaxies in order to investigate the likely origin of the spiral structure in M33. In our models, we find that gravitational instabilities in the stars and gas are able to reproduce the observed spiral pattern and velocity field of M33, as seen in HI, and no interaction is required. We also find that the optimum models have high levels of stellar feedback which create large holes similar to those observed in M33, whilst lower levels of feedback tend to produce a large amount of small scale structure, and undisturbed long filaments of high surface density gas, hardly detected in the M33 disc. The gas component appears to have a significant role in producing the structure, so if there is little feedback, both the gas and stars organise into clear spiral arms, likely due to a lower combined Q (using gas and stars), and the ready ability of cold gas to undergo spiral shocks. By contrast models with higher feedback have weaker spiral structure, especially in the stellar component, compared to grand design galaxies. We did not see a large difference in the behaviour of Qstars with most of these models, however, because Qstars stayed relatively constant unless the disc was more strongly unstable. Our models suggest that although the stars produce some underlying spiral structure, this is relatively weak, and the gas physics has a considerable role in producing the large scale structure of the ISM in flocculent spirals.

  6. Elevator frames two columns

    OpenAIRE

    Marín Jiménez, Juan Francisco

    2015-01-01

    This project aims to solve the problem of vertical transport of charges raised by a company with the standard UNE 58-132-91/6. The purpose of this project is the industrial design of a system of load handling by a bi-columned lifting device, tractioned by flat belts and steel cables from a transport level to a different level in order to connect two different assembly lines situated at different heights. The goal of this project is lifting a 780 Kg load at a 2.400 mm height....

  7. Column: Every Last Byte

    Directory of Open Access Journals (Sweden)

    Simson Garfinkel

    2011-06-01

    Full Text Available Inheritance powder is the name that was given to poisons, especially arsenic, that were commonly used in the 17th and early 18th centuries to hasten the death of the elderly. For most of the 17th century, arsenic was deadly but undetectable, making it nearly impossible to prove that someone had been poisoned. The first arsenic test produced a gas—hardly something that a scientist could show to a judge. Faced with a growing epidemic of poisonings, doctors and chemists spent decades searching for something better.(see PDF for full column

  8. Neutrons for science (NFS) at spiral-2

    International Nuclear Information System (INIS)

    Ridikas, D.

    2005-01-01

    Both cross section measurements and various applications could be realised successfully using the high energy neutrons that will be produced at SPIRAL-2. Two particular cases were examined in more detail, namely: (a) neutron time-of-flight (nToF) measurements with pulsed neutron beams, and (b) material activation-irradiation with high-energy high-intensity neutron fluxes. Thanks to the high energy and high intensity neutron flux available, SPIRAL-2 offers a unique opportunity for material irradiations both for fission and fusion related research, tests of various detection systems and of resistance of electronics components to irradiations, etc. SPIRAL-2 also could be considered as an intermediate step towards new generation dedicated irradiation facilities as IFMIF previewed only beyond 2015. Equally, the interval from 0.1 MeV to 40 MeV for neutron cross section measurements is an energy range that is of particular importance for energy applications, notably accelerator driven systems (ADS) and Gen-IV fast reactors, as well as for fusion related devices. It is also the region where pre-equilibrium approaches are often used to link the low (evaporation) and high energy (intra-nuclear cascade) reaction models. With very intense neutron beams of SPIRAL-2 measurements of very low mass (often radioactive) targets and small cross sections become feasible in short experimental campaigns. Production of radioactive targets for dedicated physics experiments is also an attractive feature of SPIRAL-2. In brief, it was shown that SPIRAL-2 has got a remarkable potential for neutron based research both for fundamental physics and various applications. In addition, in the neutron energy range from a few MeV to, say, 35 MeV this research would have a leading position for the next 10-15 years if compared to other neutron facilities in operation or under construction worldwide. (author)

  9. Kidney spiral CT, indications, realization, results

    International Nuclear Information System (INIS)

    Braunschweig, R.; Beilicke, M.; Hundt, W.; Breiteneder, T.; Reiser, M.

    1999-01-01

    The introduction of spiral computed tomography (spiral CT) has vastly enriched the methodologically diversity of computer-tomographic scans. It allows for the recording of different perfusion or excretion stages of the kidney parenchyma of the urine draining paths by carrying out long-distance, phase-identical multiple examinations of the retroperitoneum. The description of the findings which are characterized by their local and contrasts behavior is possible. The following report describes the indications and technological process of kidney spiral CT using kidney-typical intravenous contrast media. Special emphasis is put on the advantages and limits of multiple phase spiral CT. Decisive preconditions are: 1. Specific clinical query, 2. selection of the corresponding phase contrasts of the kidneys and uretra or bladder, 3. exact technical and temporal adjustment of the acquisition parameters. Scanning times are in the range of seconds. The overall examination can be carried out quick and without any major strain on the part of the patient. A sound proof and a general differentiation of focal kideny lesions can be derived from the acquired data. This is also true for kidneys and ureters findings. Bladder findings can be localized and differentiated according to stage. More than two 'spiral acquisitions' should be carried out with restraint taking exposure to radiation into account. Due to the sound registration of focal lesions, its capability of reproduction and its short-time examination, the spiral CT of the kidneys can be said to be the most effective current scanning method of the retroperitoneum following clinical examinations and sonography. (orig.) [de

  10. Annular pulse column development studies

    International Nuclear Information System (INIS)

    Benedict, G.E.

    1980-01-01

    The capacity of critically safe cylindrical pulse columns limits the size of nuclear fuel solvent extraction plants because of the limited cross-sectional area of plutonium, U-235, or U-233 processing columns. Thus, there is a need to increase the cross-sectional area of these columns. This can be accomplished through the use of a column having an annular cross section. The preliminary testing of a pilot-plant-scale annular column has been completed and is reported herein. The column is made from 152.4-mm (6-in.) glass pipe sections with an 89-mm (3.5-in.) o.d. internal tube, giving an annular width of 32-mm (1.25-in.). Louver plates are used to swirl the column contents to prevent channeling of the phases. The data from this testing indicate that this approach can successfully provide larger-cross-section critically safe pulse columns. While the capacity is only 70% of that of a cylindrical column of similar cross section, the efficiency is almost identical to that of a cylindrical column. No evidence was seen of any non-uniform pulsing action from one side of the column to the other

  11. Graphite target for the spiral project

    International Nuclear Information System (INIS)

    Putaux, J.C.; Ducourtieux, M.; Ferro, A.; Foury, P.; Kotfila, L.; Mueller, A.C.; Obert, J.; Pauwels, N.; Potier, J.C.; Proust, J.; Loiselet, M.

    1996-01-01

    A study of the thermal and physical properties of graphite targets for the SPIRAL project is presented. The main objective is to develop an optimized set-up both mechanically and thermally resistant, presenting good release properties (hot targets with thin slices). The results of irradiation tests concerning the mechanical and thermal resistance of the first prototype of SPIRAL target with conical geometry are presented. The micro-structural properties of the graphite target is also studied, in order to check that the release properties are not deteriorated by the irradiation. Finally, the results concerning the latest pilot target internally heated by an electrical current are shown. (author)

  12. Packing of equal discs on a parabolic spiral lattice

    International Nuclear Information System (INIS)

    Xudong, F.; Bursill, L.A.; Julin, P.

    1989-01-01

    A contact disc model is investigated to determine the most closely-packed parabolic spiral lattice. The most space-efficient packings have divergence angles in agreement with the priority ranking of natural spiral structures

  13. Internal slab-column connections under monotonic and cyclic imposed rotations

    OpenAIRE

    Drakatos, Ioannis-Sokratis; Muttoni, Aurelio; Beyer, Katrin

    2016-01-01

    Reinforced concrete flat slabs supported by slender columns are often used as gravity load resisting system for buildings in regions of moderate seismicity. Current codes of practice determine the displacement capacity of slab-column connections using empirical formulas which were calibrated against experimental studies. This article reviews and compares test configurations used in past experimental studies and presents the adopted configuration for an experimental investigation on 13 full-sc...

  14. Effects of a malfunctional column on conventional and FeedCol-simulated moving bed chromatography performance.

    Science.gov (United States)

    Song, Ji-Yeon; Oh, Donghoon; Lee, Chang-Ha

    2015-07-17

    The effects of a malfunctional column on the performance of a simulated moving bed (SMB) process were studied experimentally and theoretically. The experimental results of conventional four-zone SMB (2-2-2-2 configuration) and FeedCol operation (2-2-2-2 configuration with one feed column) with one malfunctional column were compared with simulation results of the corresponding SMB processes with a normal column configuration. The malfunctional column in SMB processes significantly deteriorated raffinate purity. However, the extract purity was equivalent or slightly improved compared with the corresponding normal SMB operation because the complete separation zone of the malfunctional column moved to a lower flow rate range in zones II and III. With the malfunctional column configuration, FeedCol operation gave better experimental performance (up to 7%) than conventional SMB operation because controlling product purity with FeedCol operation was more flexible through the use of two additional operating variables, injection time and injection length. Thus, compared with conventional SMB separation, extract with equivalent or slightly better purity could be produced from FeedCol operation even with a malfunctional column, while minimizing the decrease in raffinate purity (less than 2%). Copyright © 2015 Elsevier B.V. All rights reserved.

  15. The dynamics of the spiral galaxy M81

    International Nuclear Information System (INIS)

    Visser, H.C.D.

    1978-01-01

    A detailed comparison of the observations of the spiral galaxy M81 with the density-wave theory for tightly-wound spirals is presented. In particular, hydrogen-line observations are compared with the nonlinear density-wave theory for the gas with the aim of constructing a density-wave model for the spiral galaxy M81

  16. Adaptation of the control system in view of SPIRAL integration

    International Nuclear Information System (INIS)

    Lecorche, E.

    1998-01-01

    As soon as the collaboration between the SPIRAL project and the Control Group has been defined, the first implementation of the SPIRAL control system started following various directions. Both the global hardware and software architectures has been specified and some practical works have been undertaken such as the Ethernet network installation or the first SPIRAL oriented software design and coding. (authors)

  17. Software configuration management

    CERN Document Server

    Keyes, Jessica

    2004-01-01

    Software Configuration Management discusses the framework from a standards viewpoint, using the original DoD MIL-STD-973 and EIA-649 standards to describe the elements of configuration management within a software engineering perspective. Divided into two parts, the first section is composed of 14 chapters that explain every facet of configuration management related to software engineering. The second section consists of 25 appendices that contain many valuable real world CM templates.

  18. Column-to-column packing variation of disposable pre-packed columns for protein chromatography.

    Science.gov (United States)

    Schweiger, Susanne; Hinterberger, Stephan; Jungbauer, Alois

    2017-12-08

    In the biopharmaceutical industry, pre-packed columns are the standard for process development, but they must be qualified before use in experimental studies to confirm the required performance of the packed bed. Column qualification is commonly done by pulse response experiments and depends highly on the experimental testing conditions. Additionally, the peak analysis method, the variation in the 3D packing structure of the bed, and the measurement precision of the workstation influence the outcome of qualification runs. While a full body of literature on these factors is available for HPLC columns, no comparable studies exist for preparative columns for protein chromatography. We quantified the influence of these parameters for commercially available pre-packed and self-packed columns of disposable and non-disposable design. Pulse response experiments were performed on 105 preparative chromatography columns with volumes of 0.2-20ml. The analyte acetone was studied at six different superficial velocities (30, 60, 100, 150, 250 and 500cm/h). The column-to-column packing variation between disposable pre-packed columns of different diameter-length combinations varied by 10-15%, which was acceptable for the intended use. The column-to-column variation cannot be explained by the packing density, but is interpreted as a difference in particle arrangement in the column. Since it was possible to determine differences in the column-to-column performance, we concluded that the columns were well-packed. The measurement precision of the chromatography workstation was independent of the column volume and was in a range of±0.01ml for the first peak moment and±0.007 ml 2 for the second moment. The measurement precision must be considered for small columns in the range of 2ml or less. The efficiency of disposable pre-packed columns was equal or better than that of self-packed columns. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  19. CONFIGURATION GENERATOR MODEL

    International Nuclear Information System (INIS)

    Alsaed, A.

    2004-01-01

    ''The Disposal Criticality Analysis Methodology Topical Report'' prescribes an approach to the methodology for performing postclosure criticality analyses within the monitored geologic repository at Yucca Mountain, Nevada. An essential component of the methodology is the ''Configuration Generator Model for In-Package Criticality'' that provides a tool to evaluate the probabilities of degraded configurations achieving a critical state. The configuration generator model is a risk-informed, performance-based process for evaluating the criticality potential of degraded configurations in the monitored geologic repository. The method uses event tree methods to define configuration classes derived from criticality scenarios and to identify configuration class characteristics (parameters, ranges, etc.). The probabilities of achieving the various configuration classes are derived in part from probability density functions for degradation parameters. The NRC has issued ''Safety Evaluation Report for Disposal Criticality Analysis Methodology Topical Report, Revision 0''. That report contained 28 open items that required resolution through additional documentation. Of the 28 open items, numbers 5, 6, 9, 10, 18, and 19 were concerned with a previously proposed software approach to the configuration generator methodology and, in particular, the k eff regression analysis associated with the methodology. However, the use of a k eff regression analysis is not part of the current configuration generator methodology and, thus, the referenced open items are no longer considered applicable and will not be further addressed

  20. Ansible configuration management

    CERN Document Server

    Hall, Daniel

    2013-01-01

    Ansible Configuration Management"" is a step-by-step tutorial that teaches the use of Ansible for configuring Linux machines.This book is intended for anyone looking to understand the basics of Ansible. It is expected that you will have some experience of how to set up and configure Linux machines. In parts of the book we cover configuration files of BIND, MySQL, and other Linux daemons, therefore a working knowledge of these would be helpful but are certainly not required.

  1. Configuration management at NEK

    International Nuclear Information System (INIS)

    Podhraski, M.

    1999-01-01

    Configuration Management (CM) objectives at NEK are to ensure consistency between Design Requirements, Physical Plant Configuration and Configuration Information. Software applications, supporting Design Change, Work Control and Document Control Processes, are integrated in one module-oriented Management Information System (MIS). Master Equipment Component List (MECL) database is central MIS module. Through a combination of centralized database and process migrated activities it is ensured that the CM principles and requirements (accurate, current design data matching plant's physical configuration while complying to applicable requirements), are followed and fulfilled.(author)

  2. Spiral kicker for the beam abort system

    Energy Technology Data Exchange (ETDEWEB)

    Martin, R.L.

    1983-01-01

    A brief study was carried out to determine the feasibility of a special kicker to produce a damped spiral beam at the beam dump for the beam abort system. There appears to be no problem with realizing this concept at a reasonably low cost.

  3. Spiral kicker for the beam abort system

    International Nuclear Information System (INIS)

    Martin, R.L.

    1983-01-01

    A brief study was carried out to determine the feasibility of a special kicker to produce a damped spiral beam at the beam dump for the beam abort system. There appears to be no problem with realizing this concept at a reasonably low cost

  4. Irrational Numbers Can "In-Spiral" You

    Science.gov (United States)

    Lewis, Leslie D.

    2007-01-01

    This article describes the instructional process of helping students visualize irrational numbers. Students learn to create a spiral, called "the wheel of Theodorus," which demonstrates irrational and rational lengths. Examples of student work help the reader appreciate the delightful possibilities of this project. (Contains 4 figures.)

  5. Importance of packing in spiral defect chaos

    Indian Academy of Sciences (India)

    We develop two measures to characterize the geometry of patterns exhibited by the state of spiral defect chaos, a weakly turbulent regime of Rayleigh-Bénard convection. These describe the packing of contiguous stripes within the pattern by quantifying their length and nearest-neighbor distributions. The distributions ...

  6. Spiral CT-angiography of the aorta

    NARCIS (Netherlands)

    Balm, R.; Eikelboom, B. C.; van Leeuwen, M. S.; Noordzij, J.

    1994-01-01

    AIMS: To determine whether the new technique of CT-angiography was accurate in displaying the complex anatomy of the aorta and its major branches. METHODS: Seventeen patients with a variety of aortic pathology were examined. Using a spiral CT-scanner a volumetric scan was made during injection of

  7. STRUCTURED MOLECULAR GAS REVEALS GALACTIC SPIRAL ARMS

    Energy Technology Data Exchange (ETDEWEB)

    Sawada, Tsuyoshi [Joint ALMA Office, Alonso de Cordova 3107, Vitacura, Santiago 763-0355 (Chile); Hasegawa, Tetsuo [NAOJ Chile Observatory, Joaquin Montero 3000 Oficina 702, Vitacura, Santiago 763-0409 (Chile); Koda, Jin, E-mail: sawada.tsuyoshi@nao.ac.jp [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

    2012-11-01

    We explore the development of structures in molecular gas in the Milky Way by applying the analysis of the brightness distribution function and the brightness distribution index (BDI) in the archival data from the Boston University-Five College Radio Astronomy Observatory {sup 13}CO J = 1-0 Galactic Ring Survey. The BDI measures the fractional contribution of spatially confined bright molecular emission over faint emission extended over large areas. This relative quantity is largely independent of the amount of molecular gas and of any conventional, pre-conceived structures, such as cores, clumps, or giant molecular clouds. The structured molecular gas traced by higher BDI is located continuously along the spiral arms in the Milky Way in the longitude-velocity diagram. This clearly indicates that molecular gas changes its structure as it flows through the spiral arms. Although the high-BDI gas generally coincides with H II regions, there is also some high-BDI gas with no/little signature of ongoing star formation. These results support a possible evolutionary sequence in which unstructured, diffuse gas transforms itself into a structured state on encountering the spiral arms, followed by star formation and an eventual return to the unstructured state after the spiral arm passage.

  8. High-displacement spiral piezoelectric actuators

    Science.gov (United States)

    Mohammadi, F.; Kholkin, A. L.; Jadidian, B.; Safari, A.

    1999-10-01

    A high-displacement piezoelectric actuator, employing spiral geometry of a curved piezoelectric strip is described. The monolithic actuators are fabricated using a layered manufacturing technique, fused deposition of ceramics, which is capable of prototyping electroceramic components with complex shapes. The spiral actuators (2-3 cm in diameter) consisted of 4-5 turns of a lead zirconate titanate ceramic strip with an effective length up to 28 cm. The width was varied from 0.9 to 1.75 mm with a height of 3 mm. When driven by the electric field applied across the width of the spiral wall, the tip of the actuator was found to displace in both radial and tangential directions. The tangential displacement of the tip was about 210 μm under the field of 5 kV/cm. Both the displacement and resonant frequency of the spirals could be tailored by changing the effective length and wall width. The blocking force of the actuator in tangential direction was about 1 N under the field of 5 kV/cm. These properties are advantageous for high-displacement low-force applications where bimorph or monomorph actuators are currently employed.

  9. Biofouling of spiral wound membrane systems

    NARCIS (Netherlands)

    Vrouwenvelder, J.S.

    2009-01-01

    Biofouling of spiral wound membrane systems High quality drinking water can be produced with membrane filtration processes like reverse osmosis (RO) and nanofiltration (NF). Because the global demand for fresh clean water is increasing, these membrane technologies will increase in importance in the

  10. Space charge effect in the spiral inflector

    International Nuclear Information System (INIS)

    Toprek, Dragan

    2000-01-01

    This paper presents the analytical and numerical theory of the space charge effects in the beam in the spiral inflector. It considers a simplified model of a 'straight' cylindrical beam by using a uniform particle distribution. Numerical results represented in this paper are obtained by using a modified version of the program CASINO

  11. Some optical properties of the spiral inflector

    International Nuclear Information System (INIS)

    Toprek, Dragan; Subotic, Krunoslav

    1999-01-01

    This paper compares some optical properties of different spiral inflectors using the program CASINO. The electric field distribution in the inflectors has been numerically calculated from an electric potential map produced by the program RELAX3D. The magnetic field is assumed to be constant. We have also made an effort to minimize the inflector fringe field using the RELAX3D program. (author)

  12. A nutrient’s downstream spiral

    Science.gov (United States)

    Indicators of a stream’s ability to remove nutrients provide insights on watershed integrity and stream habitat characteristics that are needed to help managers to restore stream ecosystem services. We used the Tracer Additon Spiraling Characterization Curve (TASCC) to mea...

  13. Spiral groove seal. [for hydraulic rotating shaft

    Science.gov (United States)

    Ludwig, L. P. (Inventor)

    1973-01-01

    Mating flat surfaces inhibit leakage of a fluid around a stationary shaft. A spiral groove pattern produces a pumping action toward the fluid when the shaft rotates which prevents leakage while a generated hydraulic lifting force separates the mating surfaces to minimize wear.

  14. Logarithmic spiral trajectories generated by Solar sails

    Science.gov (United States)

    Bassetto, Marco; Niccolai, Lorenzo; Quarta, Alessandro A.; Mengali, Giovanni

    2018-02-01

    Analytic solutions to continuous thrust-propelled trajectories are available in a few cases only. An interesting case is offered by the logarithmic spiral, that is, a trajectory characterized by a constant flight path angle and a fixed thrust vector direction in an orbital reference frame. The logarithmic spiral is important from a practical point of view, because it may be passively maintained by a Solar sail-based spacecraft. The aim of this paper is to provide a systematic study concerning the possibility of inserting a Solar sail-based spacecraft into a heliocentric logarithmic spiral trajectory without using any impulsive maneuver. The required conditions to be met by the sail in terms of attitude angle, propulsive performance, parking orbit characteristics, and initial position are thoroughly investigated. The closed-form variations of the osculating orbital parameters are analyzed, and the obtained analytical results are used for investigating the phasing maneuver of a Solar sail along an elliptic heliocentric orbit. In this mission scenario, the phasing orbit is composed of two symmetric logarithmic spiral trajectories connected with a coasting arc.

  15. The Spiral Curriculum. Research into Practice

    Science.gov (United States)

    Johnston, Howard

    2012-01-01

    The Spiral Curriculum is predicated on cognitive theory advanced by Jerome Bruner (1960), who wrote, "We begin with the hypothesis that any subject can be taught in some intellectually honest form to any child at any stage of development." In other words, even the most complex material, if properly structured and presented, can be understood by…

  16. Spiral Growth in Plants: Models and Simulations

    Science.gov (United States)

    Allen, Bradford D.

    2004-01-01

    The analysis and simulation of spiral growth in plants integrates algebra and trigonometry in a botanical setting. When the ideas presented here are used in a mathematics classroom/computer lab, students can better understand how basic assumptions about plant growth lead to the golden ratio and how the use of circular functions leads to accurate…

  17. The Spiral-Interactive Program Evaluation Model.

    Science.gov (United States)

    Khaleel, Ibrahim Adamu

    1988-01-01

    Describes the spiral interactive program evaluation model, which is designed to evaluate vocational-technical education programs in secondary schools in Nigeria. Program evaluation is defined; utility oriented and process oriented models for evaluation are described; and internal and external evaluative factors and variables that define each…

  18. Nobeyama CO Atlas of Nearby Spiral Galaxies

    Science.gov (United States)

    Kuno, N.; Nakai, N.; Sorai, K.; Sato, N..; Yamauchi, A.; Tosaki, T.; Shioya, Y.; Vila-Vilaró, B.; Nishiyama, K.; Ishihara, Y.; Cepa, J.

    BEARS is a 25-beam focal plane array receiver mounted on the Nobeyama 45-m telescope. The combination of the large dish size of the telescope with the excellent performance of this receiver makes it an ideal tool for mapping observations of extended regions of the sky. We present here one of its current applications in a CO mapping survey of nearby spiral galaxies.

  19. Column: File Cabinet Forensics

    Directory of Open Access Journals (Sweden)

    Simson Garfinkel

    2011-12-01

    Full Text Available Researchers can spend their time reverse engineering, performing reverse analysis, or making substantive contributions to digital forensics science. Although work in all of these areas is important, it is the scientific breakthroughs that are the most critical for addressing the challenges that we face.Reverse Engineering is the traditional bread-and-butter of digital forensics research. Companies like Microsoft and Apple deliver computational artifacts (operating systems, applications and phones to the commercial market. These artifacts are bought and used by billions. Some have evil intent, and (if society is lucky, the computers end up in the hands of law enforcement. Unfortunately the original vendors rarely provide digital forensics tools that make their systems amenable to analysis by law enforcement. Hence the need for reverse engineering.(see PDF for full column

  20. 2D array design based on Fermat spiral for ultrasound imaging.

    Science.gov (United States)

    Martínez-Graullera, Oscar; Martín, Carlos J; Godoy, Gregorio; Ullate, Luis G

    2010-02-01

    The main challenge faced by 3D ultrasonic imaging with 2D array transducers is the large number of elements required to achieve an acceptable level of quality in the images. Therefore, the optimisation of the array layout, in order to reduce the number of active elements in the aperture, has been a research topic in the last years. Nowadays, array technology has made viable the production of 2D arrays with larger flexibility on elements size, shape and position, allowing to study other configurations different to the classical matrix organisation, such as circular, archimedes spiral or polygonal layout between others. In this work, the problem of designing an imaging system array with large apertures and a very limited number of active elements (N(e)=128 and N(e)=256) using the Fermat spiral layout has been studied. As summary, a general discussion about the most interesting cases is presented.

  1. Spiral CT for evaluation of chest trauma; Spiral-CT beim Thoraxtrauma

    Energy Technology Data Exchange (ETDEWEB)

    Roehnert, W. [Universitaetsklinikum Dresden (Germany). Inst. und Poliklinik fuer Radiologische Diagnostik; Weise, R. [Universitaetsklinikum Dresden (Germany). Inst. und Poliklinik fuer Radiologische Diagnostik

    1997-07-01

    After implementation of spiral CT in our department, we carried out an analysis for determining anew the value of CT as a modality of chest trauma diagnosis in the emergency department. The retrospective study covers a period of 10 months and all emergency patients with chest trauma exmined by spiral CT. The major lesions of varying seriousness covered by this study are: pneumothorax, hematothorax, pulmonary contusion or laceration, mediastinal hematoma, rupture of a vessel, injury of the heart and pericardium. The various fractures are not included in this study. In many cases, spiral CT within relatively short time yields significant diagnostic findings, frequently saving additional angiography. A rigid diagnostic procedure cannot be formulated. Plain-film chest radiography still remains a diagnostic modality of high value. (Orig.) [Deutsch] Nach Einfuehrung der Spiral-CT in unserer Einrichtung versuchten wir, den Stellenwert der Computertomographie in der Notfalldiagnostik des Thoraxtraumas neu zu bestimmen. Dazu wurden retrospektiv ueber einen Zeitraum von 10 Monaten alle mittels Spiral-CT untersuchten Notfallpatienten mit Thoraxverletzungen ausgewertet. Im Vordergrund standen folgende Befunde unterschiedlichen Schweregrades: Pneumothorax, Haematothorax, Lungenkontusion/-lazeration, Mediastinalhaematom, Gefaessruptur, Herz- und Herzbeutelverletzung. Auf die unterschiedlichen Frakturen wird bewusst nicht naeher eingegangen. In vielen Faellen liefert die Spiral-CT mit relativ geringem Zeitaufwand wesentliche diagnostische Aussagen. Haeufig kann auf eine Angiographie verzichtet werden. Ein starres diagnostisches Stufenschema laesst sich nicht definieren. Die Thoraxuebersichtsaufnahme besitzt einen unveraendert hohen Stellenwert. (orig.)

  2. Nutrient spiraling in streams and river networks

    Science.gov (United States)

    Ensign, Scott H.; Doyle, Martin W.

    2006-12-01

    Over the past 3 decades, nutrient spiraling has become a unifying paradigm for stream biogeochemical research. This paper presents (1) a quantitative synthesis of the nutrient spiraling literature and (2) application of these data to elucidate trends in nutrient spiraling within stream networks. Results are based on 404 individual experiments on ammonium (NH4), nitrate (NO3), and phosphate (PO4) from 52 published studies. Sixty-nine percent of the experiments were performed in first- and second-order streams, and 31% were performed in third- to fifth-order streams. Uptake lengths, Sw, of NH4 (median = 86 m) and PO4 (median = 96 m) were significantly different (α = 0.05) than NO3 (median = 236 m). Areal uptake rates of NH4 (median = 28 μg m-2 min-1) were significantly different than NO3 and PO4 (median = 15 and 14 μg m-2 min-1, respectively). There were significant differences among NH4, NO3, and PO4 uptake velocity (median = 5, 1, and 2 mm min-1, respectively). Correlation analysis results were equivocal on the effect of transient storage on nutrient spiraling. Application of these data to a stream network model showed that recycling (defined here as stream length ÷ Sw) of NH4 and NO3 generally increased with stream order, while PO4 recycling remained constant along a first- to fifth-order stream gradient. Within this hypothetical stream network, cumulative NH4 uptake decreased slightly with stream order, while cumulative NO3 and PO4 uptake increased with stream order. These data suggest the importance of larger rivers to nutrient spiraling and the need to consider how stream networks affect nutrient flux between terrestrial and marine ecosystems.

  3. Utilization of the ion traps by SPIRAL

    International Nuclear Information System (INIS)

    Le Brun, C.; Lienard, E.; Mauger, F.; Tamain, B.

    1997-01-01

    An ion trap is a device capable of confine particles, ions or atoms in a well-controlled environment isolated from any exterior perturbations. There are different traps. They are utilized to collect or stock ions, to cool them after in order to subject them to high precision measurement of masses, magnetic moments, hyperfine properties, beta decay properties, etc. Some dozen of traps are currently used all over the world to study stable or radioactive ions.. SPIRAL has been designed and built to produce radioactive ions starting from various heavy ion beams. SPIRAL has the advantage that the projectile parameters, the target and the energy can be chosen to optimize the production in various regions of the nuclear chart. Also, in SPIRAL it is possible to extract more rapidly the radioactive ions formed in the targets. In addition, in SPIRAL the multicharged ion production in a ECR source is possible. The utilization of multicharged ions is indeed very useful for fast mass measurements or for the study of the interaction between the nucleus and the electronic cloud. Finally, utilization of a ion trap on SPIRAL can be designed first at the level of production target by installing a low energy output line. Than, the trap system could be up-graded and brought to its full utilization behind of the recoil spectrometer. It must be capable of selecting and slowing down the ions produced in the reactions (fusion transfer, very inelastic collisions, etc.) induced by the radioactive ions accelerated in CIME. At present, the collaboration is debating on the most favored subject to study and the most suited experimental setups. The following subjects were selected: ion capture, purification and manipulation; isomers (separation and utilization); mass measurements; hyperfine interactions; lifetimes, nuclear electric cloud; β decays; study of the N = Z nuclei close to the proton drip line; physical and chemical properties of transuranium systems

  4. Molecular clouds and galactic spiral structure

    International Nuclear Information System (INIS)

    Dame, T.M.

    1983-01-01

    Galactic CO line emission at 115 GHz has been surveyed in the region 12 0 less than or equal to l less than or equal to 60 0 and -1 0 less than or equal to b less than or equal to 1 0 in order to study the distribution of molecular clouds in the inner galaxy; an inner strip 0 0 .5 wide has been sampled every beamwidth (0 0 .125), the rest every two beamwidths. Comparison of the survey with similar HI data reveals a detailed correlation with the most intense 21-cm features, implying that the CO and HI trace the same galactic features and have the same large-scale kinematics. To each of the classical 21-cm (HI) spiral arms of the inner galaxy there corresponds a CO molecular arm which is generally more clearly defined and of higher contrast. A simple model is developed in which all of the CO emission from the inner galaxy arises from spiral arms. The modeling results suggest that molecular clouds are essentially transient objects, existing for 15 to 40 million years after their formation in a spiral arm, and are largely confined to spiral features about 300 pc wide. A variety of methods are employed to estimate distances and masses for the largest clouds detected by the inner-galaxy survey and a catalogue is compiled. The catalogued clouds, the largest of which have masses of several 10 6 M/sub sunmass/ and linear dimensions in excess of 100 pc, are found to be excellent spiral-arm tracers. One of the nearest of the clouds, that associated with the supernova remnant W44, is fully mapped in both CO and 13 CO and is discussed in detail

  5. Safe Control for Spiral Recovery of Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Chang-Jian Ru

    2014-01-01

    Full Text Available With unmanned aerial vehicles (UAVs widely used in both military and civilian fields, many events affecting their safe flying have emerged. That UAV’s entering into the spiral is such a typical safety issue. To solve this safety problem, a novel recovery control approach is proposed. First, the factors of spiral are analyzed. Then, based on control scheduling of state variables and nonlinear dynamic inversion control laws, the spiral recovery controller is designed to accomplish guidance and control of spiral recovery. Finally, the simulation results have illustrated that the proposed control method can ensure the UAV autonomous recovery from spiral effectively.

  6. Compact electron beam focusing column

    Science.gov (United States)

    Persaud, Arun; Leung, Ka-Ngo; Reijonen, Jani

    2001-12-01

    A novel design for an electron beam focusing column has been developed at LBNL. The design is based on a low-energy spread multicusp plasma source which is used as a cathode for electron beam production. The focusing column is 10 mm in length. The electron beam is focused by means of electrostatic fields. The column is designed for a maximum voltage of 50 kV. Simulations of the electron trajectories have been performed by using the 2D simulation code IGUN and EGUN. The electron temperature has also been incorporated into the simulations. The electron beam simulations, column design and fabrication will be discussed in this presentation.

  7. Simulator configuration maintenance

    International Nuclear Information System (INIS)

    2006-01-01

    Requirements and recommendations of this section defines NPP personnel activity aimed to the provision of the simulator configuration compliance with the current configuration of the power-generating unit-prototype, standard and technical requirements and describe a monitoring procedure for a set of simulator software and hardware, training, organizational and technical documents

  8. PIV Logon Configuration Guidance

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Glen Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-04

    This document details the configurations and enhancements implemented to support the usage of federal Personal Identity Verification (PIV) Card for logon on unclassified networks. The guidance is a reference implementation of the configurations and enhancements deployed at the Los Alamos National Laboratory (LANL) by Network and Infrastructure Engineering – Core Services (NIE-CS).

  9. Business Model Process Configurations

    DEFF Research Database (Denmark)

    Taran, Yariv; Nielsen, Christian; Thomsen, Peter

    2015-01-01

    , by developing (inductively) an ontological classification framework, in view of the BM process configurations typology developed. Design/methodology/approach – Given the inconsistencies found in the business model studies (e.g. definitions, configurations, classifications) we adopted the analytical induction...

  10. Risk-based configuration control

    International Nuclear Information System (INIS)

    Szikszai, T.

    1997-01-01

    The presentation discusses the following issues: The Configuration Control; The Risk-based Configuration Control (during power operation mode, and during shutdown mode). PSA requirements. Use of Risk-based Configuration Control System. Configuration Management (basic elements, benefits, information requirements)

  11. How does a planet excite multiple spiral arms?

    Science.gov (United States)

    Bae, Jaehan; Zhu, Zhaohuan

    2018-01-01

    Protoplanetary disk simulations show that a single planet excites multiple spiral arms in the background disk, potentially supported by the multi-armed spirals revealed with recent high-resolution observations in some disks. The existence of multiple spiral arms is of importance in many aspects. It is empirically found that the arm-to-arm separation increases as a function of the planetary mass, so one can use the morphology of observed spiral arms to infer the mass of unseen planets. In addition, a spiral arm opens a radial gap as it steepens into a shock, so when a planet excites multiple spiral arms it can open multiple gaps in the disk. Despite the important implications, however, the formation mechanism of multiple spiral arms has not been fully understood by far.In this talk, we explain how a planet excites multiple spiral arms. The gravitational potential of a planet can be decomposed into a Fourier series, a sum of individual azimuthal modes having different azimuthal wavenumbers. Using a linear wave theory, we first demonstrate that appropriate sets of Fourier decomposed waves can be in phase, raising a possibility that constructive interference among the waves can produce coherent structures - spiral arms. More than one spiral arm can form since such constructive interference can occur at different positions in the disk for different sets of waves. We then verify this hypothesis using a suite of two-dimensional hydrodynamic simulations. Finally, we present non-linear behavior in the formation of multiple spiral arms.

  12. Theory of the propagation dynamics of spiral edges of diffusion flames in von Karman swirling flows

    Energy Technology Data Exchange (ETDEWEB)

    Urzay, Javier; Williams, Forman A. [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093-0411 (United States); Nayagam, Vedha [National Center for Space Exploration Research, NASA Glenn Research Center, Cleveland, OH 44135 (United States)

    2011-02-15

    This analysis addresses the propagation of spiral edge flames found in von Karman swirling flows induced in rotating porous-disk burners. In this configuration, a porous disk is spun at a constant angular velocity in an otherwise quiescent oxidizing atmosphere. Gaseous methane is injected through the disk pores and burns in a flat diffusion flame adjacent to the disk. Among other flame patterns experimentally found, a stable, rotating spiral flame is observed for sufficiently large rotation velocities and small fuel flow rates as a result of partial extinction of the underlying diffusion flame. The tip of the spiral can undergo a steady rotation for sufficiently large rotational velocities or small fuel flow rates, whereas a meandering tip in an epicycloidal trajectory is observed for smaller rotational velocities and larger fuel flow rates. A formulation of this problem is presented in the equidiffusional and thermodiffusive limits within the framework of one-step chemistry with large activation energies. Edge-flame propagation regimes are obtained by scaling analyses of the conservation equations and exemplified by numerical simulations of straight two-dimensional edge flames near a cold porous wall, for which lateral heat losses to the disk and large strains induce extinction of the trailing diffusion flame but are relatively unimportant in the front region, consistent with the existence of the cooling tail found in the experiments. The propagation dynamics of a steadily rotating spiral edge is studied in the large-core limit, for which the characteristic Markstein length is much smaller than the distance from the center at which the spiral tip is anchored. An asymptotic description of the edge tangential structure is obtained, spiral edge shapes are calculated, and an expression is found that relates the spiral rotational velocity to the rest of the parameters. A quasiestatic stability analysis of the edge shows that the edge curvature at extinction in the tip

  13. Model for the local spiral structure of the galaxy

    International Nuclear Information System (INIS)

    Humphreys, R.M.

    1976-01-01

    The spatial distribution of the most luminous stars, associations, clusters, and H II regions in the region l = 270 0 to 30 0 reveal a major spiral arm, Sagittarius-Carina, which can be observed to 9 or 10 kpc from the sun in the direction l = 290 0 to 305 0 . Evidence is also presented for a spur at l = 305 0 to 310 0 on the inner side of the Saggitarius-Carina arm. The noncircular motions observed in the Carina and Sagittarius spiral features agree in both magnitude and direction and support the suggestion that Sagittarius-Carina is a major spiral arm. A model is presented for the local spiral structure with wide, massive, spiral arms which show fragmentation in our region of the Galaxy. On the basis of the optical spiral structure, the Milky Way is an Sc type spiral galaxy, perhaps of the M 101 type

  14. Mechanism of spiral formation in heterogeneous discretized excitable media.

    Science.gov (United States)

    Kinoshita, Shu-ichi; Iwamoto, Mayuko; Tateishi, Keita; Suematsu, Nobuhiko J; Ueyama, Daishin

    2013-06-01

    Spiral waves on excitable media strongly influence the functions of living systems in both a positive and negative way. The spiral formation mechanism has thus been one of the major themes in the field of reaction-diffusion systems. Although the widely believed origin of spiral waves is the interaction of traveling waves, the heterogeneity of an excitable medium has recently been suggested as a probable cause. We suggest one possible origin of spiral waves using a Belousov-Zhabotinsky reaction and a discretized FitzHugh-Nagumo model. The heterogeneity of the reaction field is shown to stochastically generate unidirectional sites, which can induce spiral waves. Furthermore, we found that the spiral wave vanished with only a small reduction in the excitability of the reaction field. These results reveal a gentle approach for controlling the appearance of a spiral wave on an excitable medium.

  15. ON THE STAR FORMATION LAW FOR SPIRAL AND IRREGULAR GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Elmegreen, Bruce G., E-mail: bge@us.ibm.com [IBM Research Division, T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States)

    2015-12-01

    A dynamical model for star formation on a galactic scale is proposed in which the interstellar medium is constantly condensing to star-forming clouds on the dynamical time of the average midplane density, and the clouds are constantly being disrupted on the dynamical timescale appropriate for their higher density. In this model, the areal star formation rate scales with the 1.5 power of the total gas column density throughout the main regions of spiral galaxies, and with a steeper power, 2, in the far outer regions and in dwarf irregular galaxies because of the flaring disks. At the same time, there is a molecular star formation law that is linear in the main and outer parts of disks and in dIrrs because the duration of individual structures in the molecular phase is also the dynamical timescale, canceling the additional 0.5 power of surface density. The total gas consumption time scales directly with the midplane dynamical time, quenching star formation in the inner regions if there is no accretion, and sustaining star formation for ∼100 Gyr or more in the outer regions with no qualitative change in gas stability or molecular cloud properties. The ULIRG track follows from high densities in galaxy collisions.

  16. Safety barriers and lighting columns.

    NARCIS (Netherlands)

    Schreuder, D.A.

    1972-01-01

    Problems arising from the sitting of lighting columns on the central reserve are reviewed, and remedial measures such as break-away lighting supports and installation of safety fences on the central reserve on both sides of the lighting columns are examined.

  17. Radial distributions of arm-gas offsets as an observational test of spiral theories

    OpenAIRE

    Baba, Junichi; Morokuma-Matsui, Kana; Egusa, Fumi

    2015-01-01

    Theories of stellar spiral arms in disk galaxies can be grouped into two classes based on the longevity of a spiral arm. Although the quasi-stationary density wave theory supposes that spirals are rigidly-rotating, long-lived patterns, the dynamic spiral theory predicts that spirals are differentially-rotating, transient, recurrent patterns. In order to distinguish between the two spiral models from observations, we performed hydrodynamic simulations with steady and dynamic spiral models. Hyd...

  18. Optimal synthesis and design of extractive distillation systems for bioethanol separation: From simple to complex columns

    DEFF Research Database (Denmark)

    Errico, M.; Rong, B. G.; Tola, G.

    2013-01-01

    Bioethanol has been considered as a green fuel and a valid alternative to reduce the dependence on fossil distillates. The development of an optimal separation process is considered as a key element in the design of an efficient process able to be cost effective and competitive. Despite many....... The subspace of simple distillation configurations was generated considering the possibility to employ partial or total condensers to transfer the non-product mixtures between the columns, moreover different numbers of columns are considered. Once the most promising sequences are obtained, the complex columns...... considering the total condenser and reboiler duty as energy index. The capital costs and the solvent consumption are also taken into account in the final selection. Among all the complex configurations considered the two-column sequence can reduce the capital cost above 10% compared to the best simple column...

  19. Spiral optical designs for nonimaging applications

    Science.gov (United States)

    Zamora, Pablo; Benítez, Pablo; Miñano, Juan C.; Vilaplana, Juan; Buljan, Marina

    2011-10-01

    Manufacturing technologies as injection molding or embossing specify their production limits for minimum radii of the vertices or draft angle for demolding, for instance. In some demanding nonimaging applications, these restrictions may limit the system optical efficiency or affect the generation of undesired artifacts on the illumination pattern. A novel manufacturing concept is presented here, in which the optical surfaces are not obtained from the usual revolution symmetry with respect to a central axis (z axis), but they are calculated as free-form surfaces describing a spiral trajectory around z axis. The main advantage of this new concept lies in the manufacturing process: a molded piece can be easily separated from its mold just by applying a combination of rotational movement around axis z and linear movement along axis z, even for negative draft angles. Some of these spiral symmetry examples will be shown here, as well as their simulated results.

  20. Diagnosing extracranial atherosclerotic diseases with spiral CT

    International Nuclear Information System (INIS)

    Moran, C.J.; Vannier, M.W.; Erickson, K.K.; Broderick, D.F.; Kido, D.K.; Yoffie, R.L.

    1991-01-01

    This paper reports that this discovery study was performed to determine whether extracranial carotid artery plaques could be diagnosed with a new CT technique (spiral CT) that allows nondistorted three-dimensional (3D) reconstructions in the z axis. Twenty carotid arteries were examined with spiral CT in normal volunteers and in patients suspected of having atherosclerotic plaques in the extracranial carotid arteries. The Somatom Plus CT table was advanced at a constant rate, the x-ray tube was continuously rotated, and 3D data were continuously acquired. Sixty milliliters of nonionic contrast medium was injected intravenously previous to and during the acquisition of data. The carotid bifurcations were identified in all patients. Planar images, similar to conventional intraarterial angiograms, were routinely produced from the volumetric CT data

  1. Status of the SPIRAL2 injector commissioning

    Energy Technology Data Exchange (ETDEWEB)

    Thuillier, T., E-mail: thuillier@lpsc.in2p3.fr; Angot, J.; Jacob, J.; Lamy, T.; Sole, P. [LPSC, Université Grenoble Alpes, CNRS/IN2P3, 53 rue des Martyrs, 38026 Grenoble Cedex (France); Barué, C.; Bertrand, P.; Canet, C.; Ferdinand, R.; Flambard, J.-L.; Jardin, P.; Lemagnen, F.; Maunoury, L.; Osmond, B. [GANIL, CNRS/IN2P3, Bvd Henri Becquerel, BP 55027, 14076 Caen Cedex 5 (France); Biarrotte, J. L. [IPN Orsay, Université Paris Sud, CNRS/IN2P3, 15 rue Georges Clémenceau, 91406 Orsay Cedex (France); Denis, J.-F.; Roger, A.; Touzery, R.; Tuske, O.; Uriot, D. [Irfu, CEA Saclay, DSM/Irfu/SACM, 91191 Gif Sur Yvette (France); and others

    2016-02-15

    The SPIRAL2 injector, installed in its tunnel, is currently under commissioning at GANIL, Caen, France. The injector is composed of two low energy beam transport lines: one is dedicated to the light ion beam production, the other to the heavy ions. The first light ion beam, created by a 2.45 GHz electron cyclotron resonance ion source, has been successfully produced in December 2014. The first beam of the PHOENIX V2 18 GHz heavy ion source was analyzed on 10 July 2015. A status of the SPIRAL2 injector commissioning is given. An upgrade of the heavy ion source, named PHOENIX V3 aimed to replace the V2, is presented. The new version features a doubled plasma chamber volume and the high charge state beam intensity is expected to increase by a factor of 1.5 to 2 up to the mass ∼50. A status of its assembly is proposed.

  2. Rolling motions in an inner spiral arm

    International Nuclear Information System (INIS)

    Strauss, F.M.; Poeppel, W.

    1976-01-01

    Hydrogen line observations made at low galactic latitudes for l=318degree, 326degree, 334degree, and 337degree show the presence of velocity gradients in latitude in the nearest inner spiral arm, similar to those found by other observations in different regions. Maximum velocity change is about 10 km s -1 for l=337degree. By generating synthetic line profiles constructed from a model spiral arm, several possible causes of these ''rolling motions'' were studied, such as a vertical displacement or a tilt of the arm (which failed to account for the observations) and rotation or shearing in the arm. It was futher shown that a typical arm can maintain such a motion (approx. =75 km s -1 kpc -1 ) with its own gravitational potential. The results are used to study the origin and tilt of Gould's Belt

  3. Stationary spiral flow in polytropic stellar models

    Science.gov (United States)

    Pekeris, C. L.

    1980-01-01

    It is shown that, in addition to the static Emden solution, a self-gravitating polytropic gas has a dynamic option in which there is stationary flow along spiral trajectories wound around the surfaces of concentric tori. The motion is obtained as a solution of a partial differential equation which is satisfied by the meridional stream function, coupled with Poisson's equation and a Bernoulli-type equation for the pressure (density). The pressure is affected by the whole of the Bernoulli term rather than by the centrifugal part only, which acts for a rotating model, and it may be reduced down to zero at the center. The spiral type of flow is illustrated for an incompressible fluid (n = 0), for which an exact solution is obtained. The features of the dynamic constant-density model are discussed as a basis for future comparison with the solution for compressible models. PMID:16592825

  4. Design of zeolite ion-exchange columns for wastewater treatment

    International Nuclear Information System (INIS)

    Robinson, S.M.; Arnold, W.D.; Byers, C.H.

    1991-01-01

    Oak Ridge National Laboratory plans to use chabazite zeolites for decontamination of wastewater containing parts-per-billion levels of 90 Sr and 137 Cs. Treatability studies indicate that such zeolites can remove trace amounts of 90 Sr and 137 Cs from wastewater containing high concentrations of calcium and magnesium. These studies who that zeolite system efficiency is dependent on column design and operating conditions. Previous results with bench-scale, pilot-scale, and near-full-scale columns indicate that optimized design of full-scale columns could reduce the volume of spent solids generation by one-half. The data indicate that shortcut scale-up methods cannot be used to design columns to minimize secondary waste generation. Since the secondary waste generation rate is a primary influence on process cost effectiveness, a predictive mathematical model for column design is being developed. Equilibrium models and mass-transfer mechanisms are being experimentally determined for isothermal multicomponent ion exchange (Ca, Mg, Na, Cs, and Sr). Mathematical models of these data to determine the breakthrough curves for different column configurations and operating conditions will be used to optimize the final design of full-scale treatment plant. 32 refs., 6 figs., 3 tabs

  5. Mush Column Magma Chambers

    Science.gov (United States)

    Marsh, B. D.

    2002-12-01

    Magma chambers are a necessary concept in understanding the chemical and physical evolution of magma. The concept may well be similar to a transfer function in circuit or time series analysis. It does what needs to be done to transform source magma into eruptible magma. In gravity and geodetic interpretations the causative body is (usually of necessity) geometrically simple and of limited vertical extent; it is clearly difficult to `see' through the uppermost manifestation of the concentrated magma. The presence of plutons in the upper crust has reinforced the view that magma chambers are large pots of magma, but as in the physical representation of a transfer function, actual magma chambers are clearly distinct from virtual magma chambers. Two key features to understanding magmatic systems are that they are vertically integrated over large distances (e.g., 30-100 km), and that all local magmatic processes are controlled by solidification fronts. Heat transfer considerations show that any viable volcanic system must be supported by a vertically extensive plumbing system. Field and geophysical studies point to a common theme of an interconnected stack of sill-like structures extending to great depth. This is a magmatic Mush Column. The large-scale (10s of km) structure resembles the vertical structure inferred at large volcanic centers like Hawaii (e.g., Ryan et al.), and the fine scale (10s to 100s of m) structure is exemplified by ophiolites and deeply eroded sill complexes like the Ferrar dolerites of the McMurdo Dry Valleys, Antarctica. The local length scales of the sill reservoirs and interconnecting conduits produce a rich spectrum of crystallization environments with distinct solidification time scales. Extensive horizontal and vertical mushy walls provide conditions conducive to specific processes of differentiation from solidification front instability to sidewall porous flow and wall rock slumping. The size, strength, and time series of eruptive behavior

  6. Gastric spiral bacteria in small felids.

    Science.gov (United States)

    Kinsel, M J; Kovarik, P; Murnane, R D

    1998-06-01

    Nine small cats, including one bobcat (Felis rufus), one Pallas cat (F. manul), one Canada lynx (F. lynx canadensis), two fishing cats (F. viverrina), two margays (F. wiedii), and two sand cats (F. margarita), necropsied between June 1995 and March 1997 had large numbers of gastric spiral bacteria, whereas five large cats, including one African lion (Panthera leo), two snow leopards (P. uncia), one Siberian tiger (P. tigris altaica), and one jaguar (P. onca), necropsied during the same period had none. All of the spiral organisms from the nine small cats were histologically and ultrastructurally similar. Histologically, the spiral bacteria were 5-14 microm long with five to nine coils per organism and were located both extracellularly within gastric glands and surface mucus, and intracellularly in parietal cells. Spiral bacteria in gastric mucosal scrapings from the Canada lynx, one fishing cat, and the two sand cats were gram negative and had corkscrewlike to tumbling motility when viewed with phase contrast microscopy. The bacteria were 0.5-0.7 microm wide, with a periodicity of 0.65-1.1 microm in all cats. Bipolar sheathed flagella were occasionally observed, and no periplasmic fibrils were seen. The bacteria were extracellular in parietal cell canaliculi and intracellular within parietal cells. Culture of mucosal scrapings from the Canada lynx and sand cats was unsuccessful. Based on morphology, motility, and cellular tropism, the bacteria were probably Helicobacter-like organisms. Although the two margays had moderate lymphoplasmacytic gastritis, the other cats lacked or had only mild gastric lymphoid infiltrates, suggesting that these organisms are either commensals or opportunistic pathogens.

  7. Star distribution in the Orion spiral arm

    International Nuclear Information System (INIS)

    Basharina, T.S.; Pavlovskaya, E.D.; Filippova, A.A.

    1985-01-01

    The structure of the Orion spiral arm is studied by numerical experiments, assuming that in each direction considered the star distribution along the line of sight is a combination of two Gaussian laws. The corresponding parameters are evaluated for four Milky Way fields; the bimodal laws now fit the observations by the chi 2 criterion. In the Orion arm the line-of-sight star densities follow asymmetric curves, steeper at the outer edge of the arm

  8. The surface brightness of spiral galaxies

    International Nuclear Information System (INIS)

    Phillipps, S.; Disney, M.

    1983-01-01

    It is proposed that Freeman's discovery that the extrapolated central surface brightness of spiral galaxies is approximately constant can be simply explained if the galaxies contain a spheroidal component which dominates the light in their outer isophotes. Calculations of an effective central surface brightness indicate a wide spread of values. This requires either a wide spread in disc properties or significant spheroidal components or, most probably, both. (author)

  9. A Fermat's spiral multifilament-core fiber

    Science.gov (United States)

    Tartara, L.; Codemard, C.

    2013-02-01

    A multifilament-core optical fiber where the microstructure is arranged in a Fermat's spiral is presented. The properties of such a fiber to be exploited for laser light amplification are numerically investigated by means of a full-vectorial finite-element method. Thanks to this peculiar microstructure, the fiber is shown to have an increased Brillouin threshold power and very low bending losses, while preserving a very good beam spatial quality.

  10. Spiral-arm instability: giant clump formation via fragmentation of a galactic spiral arm

    Science.gov (United States)

    Inoue, Shigeki; Yoshida, Naoki

    2018-03-01

    Fragmentation of a spiral arm is thought to drive the formation of giant clumps in galaxies. Using linear perturbation analysis for self-gravitating spiral arms, we derive an instability parameter and define the conditions for clump formation. We extend our analysis to multicomponent systems that consist of gas and stars in an external potential. We then perform numerical simulations of isolated disc galaxies with isothermal gas, and compare the results with the prediction of our analytic model. Our model describes accurately the evolution of the spiral arms in our simulations, even when spiral arms dynamically interact with one another. We show that most of the giant clumps formed in the simulated disc galaxies satisfy the instability condition. The clump masses predicted by our model are in agreement with the simulation results, but the growth time-scale of unstable perturbations is overestimated by a factor of a few. We also apply our instability analysis to derive scaling relations of clump properties. The expected scaling relation between the clump size, velocity dispersion, and circular velocity is slightly different from that given by the Toomre instability analyses, but neither is inconsistent with currently available observations. We argue that the spiral-arm instability is a viable formation mechanism of giant clumps in gas-rich disc galaxies.

  11. The LHCb configuration database

    CERN Document Server

    Abadie, Lana; Gaspar, Clara; Jacobsson, Richard; Jost, Beat; Neufeld, Niko

    2005-01-01

    The Experiment Control System (ECS) will handle the monitoring, configuration and operation of all the LHCb experimental equipment. All parameters required to configure electronics equipment under the control of the ECS will reside in a configuration database. The database will contain two kinds of information: 1.\tConfiguration properties about devices such as hardware addresses, geographical location, and operational parameters associated with particular running modes (dynamic properties). 2.\tConnectivity between devices : this consists of describing the output and input connections of a device (static properties). The representation of these data using tables must be complete so that it can provide all the required information to the ECS and must cater for all the subsystems. The design should also guarantee a fast response time, even if a query results in a large volume of data being loaded from the database into the ECS. To fulfil these constraints, we apply the following methodology: Determine from the d...

  12. Drupal 8 configuration management

    CERN Document Server

    Borchert, Stefan

    2015-01-01

    Drupal 8 Configuration Management is intended for people who use Drupal 8 to build websites, whether you are a hobbyist using Drupal for the first time, a long-time Drupal site builder, or a professional web developer.

  13. Configuration by Modularisation

    DEFF Research Database (Denmark)

    Riitahuhta, Asko; Andreasen, Mogens Myrup

    1998-01-01

    Globally operating companies have realized that locally customized products and services are today the prerequisite for the success. The capability or the paradigm to act locally in global markets is called Mass Customization [Victor 1997]. The prerequisite for Mass Customization is Configuration...... Management and i Configuration Management the most important means is Modularisation.The goal of this paper is to show Configuration Management as a contribution to the Mass Customisation and Modularisation as a contribution to the industrialisation of the design area [Andreasen 1997]. A basic model...... for the creation of a structured product family is presented and examples are given. The concepts of a novel Dynamic Modularisation method, Metrics for Modularisation and Design for Configurability are presented....

  14. Configuration Management Automation (CMA) -

    Data.gov (United States)

    Department of Transportation — Configuration Management Automation (CMA) will provide an automated, integrated enterprise solution to support CM of FAA NAS and Non-NAS assets and investments. CMA...

  15. Computer software configuration management

    International Nuclear Information System (INIS)

    Pelletier, G.

    1987-08-01

    This report reviews the basic elements of software configuration management (SCM) as defined by military and industry standards. Several software configuration management standards are evaluated given the requirements of the nuclear industry. A survey is included of available automated tools for supporting SCM activities. Some information is given on the experience of establishing and using SCM plans of other organizations that manage critical software. The report concludes with recommendations of practices that would be most appropriate for the nuclear power industry in Canada

  16. Incorporating hydrologic variability into nutrient spiraling

    Science.gov (United States)

    Doyle, Martin W.

    2005-09-01

    Nutrient spiraling describes the path of a nutrient molecule within a stream ecosystem, combining the biochemical cycling processes with the downstream driving force of stream discharge. To date, nutrient spiraling approaches have been hampered by their inability to deal with fluctuating flows, as most studies have characterized nutrient retention within only a small range of discharges near base flow. Here hydrologic variability is incorporated into nutrient spiraling theory by drawing on the fluvial geomorphic concept of effective discharge. The effective discharge for nutrient retention is proposed to be that discharge which, over long periods of time, is responsible for the greatest portion of nutrient retention. A developed analytical model predicts that the effective discharge for nutrient retention will equal the modal discharge for small streams or those with little discharge variability. As modal discharge increases or discharge variability increases, the effective discharge becomes increasingly less than the modal discharge. In addition to the effective discharge, a new metric is proposed, the functionally equivalent discharge, which is the single discharge that will reproduce the magnitude of nutrient retention generated by the full hydrologic frequency distribution when all discharge takes place at that rate. The functionally equivalent discharge was found to be the same as the modal discharge at low hydrologic variability, but increasingly different from the modal discharge at large hydrologic variability. The functionally equivalent discharge provides a simple quantitative means of incorporating hydrologic variability into long-term nutrient budgets.

  17. Rarefied, rotational gas flows in spiral galaxies

    International Nuclear Information System (INIS)

    Roberts, W.W. Jr.; Hausman, M.A.

    1983-01-01

    We develop a computational model of a rotating, rarefied gas in which the individual molecules collide inelastically and are subject to circularly asymmetric external forces and internal heating sources. This model is applied to the interstellar medium (ISM) of spiral galaxies, in which most of the matter is confined to discrete gas clouds separated by a tenuous intercloud medium. We identify inelastically-colliding gas molecules with interstellar clouds which orbit ballistically in the galactic gravitational field and are perturbed by expanding shells surrounding supernovae. When a small, spiral perturbation is added to the gravitational force to mimic a spiral galaxy, the cloud distribution responds with a strong, global shock. In the model, stars are formed from the gas when clouds collide or are perturbed by supernovae; these stars are the internal heating sources for the gas cloud system. We determine the morphologies (evolution, distribution) of the two components, gas and stars, in the model as functions of varying input physics. Variation of the cloud system's collisional mean free path (over physically-realistic ranges) has remarkably little influence on the computed shock structure

  18. The 1+/n+ solution for SPIRAL ?

    International Nuclear Information System (INIS)

    Villari, A.C.C.; Bruandet, J.S.; Chauvin, N.; Curdy, J.C.; Gaubert, G.; Lamy, T.; Maunoury, L.; Sole, J.P.; Sortais, P.; Vieux-Rochaz, J.L.

    1997-01-01

    The use of a primary ion source for the production of 1+ ions in the production cave of SPIRAL with subsequent injection in an ECRIS (Electron Cyclotron Resonance Ion Source) for charge multiplication is discussed. The first results obtained at ISN Grenoble for the production of Rb (9+) and Ar (8+) stable beams are presented. The overall efficiency of this system for the production of the Ar beams is compared with the present situation where the ECRIS is placed inside the cave of SPIRAL. An important gain in the reliability and reduction of functioning costs would be obtained in the case of the implementation of the 1+/n+ mode in the SPIRAL project at GANIL. A reduction of overall efficiency of a factor 1.5 to 3 with respect to the present NANOGAN-II ensemble is expected for light noble gas radioactive ion beams. This factor can be reduced depending on the choice of the ECRIS for a particular multicharged ion production. Finally, important R and D is needed for extending the range of elements to be produced in the 1+/n+ mode and to define 'good' ion sources with small energy dispersion for 1+ production. (authors)

  19. Transitions between Taylor vortices and spirals via wavy Taylor vortices and wavy spirals

    International Nuclear Information System (INIS)

    Hoffmann, Ch; Altmeyer, S; Pinter, A; Luecke, M

    2009-01-01

    We present numerical simulations of closed wavy Taylor vortices and of helicoidal wavy spirals in the Taylor-Couette system. These wavy structures appearing via a secondary bifurcation out of Taylor vortex flow and out of spiral vortex flow, respectively, mediate transitions between Taylor and spiral vortices and vice versa. Structure, dynamics, stability and bifurcation behaviour are investigated in quantitative detail as a function of Reynolds numbers and wave numbers for counter-rotating as well as corotating cylinders. These results are obtained by solving the Navier-Stokes equations subject to axial periodicity for a radius ratio η=0.5 with a combination of a finite differences method and a Galerkin method.

  20. Column-Oriented Database Systems (Tutorial)

    NARCIS (Netherlands)

    D. Abadi; P.A. Boncz (Peter); S. Harizopoulos

    2009-01-01

    textabstractColumn-oriented database systems (column-stores) have attracted a lot of attention in the past few years. Column-stores, in a nutshell, store each database table column separately, with attribute values belonging to the same column stored contiguously, compressed, and densely packed, as

  1. Ablation acceleration of macroparticle in spiral magnetic fields

    International Nuclear Information System (INIS)

    Ikuta, Kazunari.

    1981-05-01

    The rocket motion of macroparticles heated by energetic pulses in a spiral magnetic field was studied. The purpose of the present work is to study the ablation acceleration of a macroparticle in a spiral magnetic field with the help of the law of conservation of angular momentum. The basic equation of motion of ablatively accelerated projectile in a spiral magnetic field was derived. Any rocket which is ejecting fully ionized plasma in an intense magnetic field with rotational transform is able to have spin by the law of conservation of momentum. The effect of spiral magnetic field on macroparticle acceleration is discussed. The necessary mass ratio increase exponentially with respect to the field parameter. The spiral field should be employed with care to have only to stabilize the position of macroparticles. As conclusion, it can be said that the ablation acceleration of the projectile in a spiral field can give the accelerated body spin quite easily. (Kato, T.)

  2. Mechanical response of spiral interconnect arrays for highly stretchable electronics

    KAUST Repository

    Qaiser, Nadeem

    2017-11-21

    A spiral interconnect array is a commonly used architecture for stretchable electronics, which accommodates large deformations during stretching. Here, we show the effect of different geometrical morphologies on the deformation behavior of the spiral island network. We use numerical modeling to calculate the stresses and strains in the spiral interconnects under the prescribed displacement of 1000 μm. Our result shows that spiral arm elongation depends on the angular position of that particular spiral in the array. We also introduce the concept of a unit-cell, which fairly replicates the deformation mechanism for full complex hexagon, diamond, and square shaped arrays. The spiral interconnects which are axially connected between displaced and fixed islands attain higher stretchability and thus experience the maximum deformations. We perform tensile testing of 3D printed replica and find that experimental observations corroborate with theoretical study.

  3. Optical and theoretical studies of giant clouds in spiral galaxies

    International Nuclear Information System (INIS)

    Elmegreen, B.G.; Elmegreen, D.M.

    1980-01-01

    An optical study of four spiral galaxies, combined with radiative transfer models for transmitted and scattered light, has led to a determination of the opacities and masses of numerous dark patches and dust lanes that outline spiral structure. The observed compression factors for the spiral-like dust lanes are in accord with expectations from the theory of gas flow in spiral density waves. Several low density (10 2 cm -3 ) clouds containing 10 6 to 10 7 solar masses were also studied. These results are discussed in terms of recent theoretical models of cloud and star formation in spiral galaxies. The long-term evolution of giant molecular clouds is shown to have important consequences for the positions and ages of star formation sites in spiral arms. (Auth.)

  4. Wave-particle dualism of spiral waves dynamics.

    Science.gov (United States)

    Biktasheva, I V; Biktashev, V N

    2003-02-01

    We demonstrate and explain a wave-particle dualism of such classical macroscopic phenomena as spiral waves in active media. That means although spiral waves appear as nonlocal processes involving the whole medium, they respond to small perturbations as effectively localized entities. The dualism appears as an emergent property of a nonlinear field and is mathematically expressed in terms of the spiral waves response functions, which are essentially nonzero only in the vicinity of the spiral wave core. Knowledge of the response functions allows quantitatively accurate prediction of the spiral wave drift due to small perturbations of any nature, which makes them as fundamental characteristics for spiral waves as mass is for the condensed matter.

  5. Mechanical response of spiral interconnect arrays for highly stretchable electronics

    KAUST Repository

    Qaiser, Nadeem; Khan, S. M.; Nour, Maha A.; Rehman, M. U.; Rojas, J. P.; Hussain, Muhammad Mustafa

    2017-01-01

    A spiral interconnect array is a commonly used architecture for stretchable electronics, which accommodates large deformations during stretching. Here, we show the effect of different geometrical morphologies on the deformation behavior of the spiral island network. We use numerical modeling to calculate the stresses and strains in the spiral interconnects under the prescribed displacement of 1000 μm. Our result shows that spiral arm elongation depends on the angular position of that particular spiral in the array. We also introduce the concept of a unit-cell, which fairly replicates the deformation mechanism for full complex hexagon, diamond, and square shaped arrays. The spiral interconnects which are axially connected between displaced and fixed islands attain higher stretchability and thus experience the maximum deformations. We perform tensile testing of 3D printed replica and find that experimental observations corroborate with theoretical study.

  6. Studies on cryogenic distillation columns for hydrogen isotope separation

    International Nuclear Information System (INIS)

    Kinoshita, Masahiro

    1984-08-01

    Cryogenic distillation is applicable to a number of situations. The feed condition, column cascade configuration, input and output specifications vary greatly from situation to situation. In the mainstream fuel circulation system for a fusion reactor, the feed composition may fluctuate greatly during the operation. The radiological standards for tritium lost to the environment are increasingly becoming stricter. Systematic studies are needed to achieve the goal of long-term operation meeting the strict requirements for products even under great fluctuation of the feed condition in all the situations. The present report gives a critical, brief review of the studies which have been made by the author. The subjects treated are development of computer simulation procedures, analysis on an H-T separation column with a feedback stream, dynamics and control, proposal of a new cascade, analysis on helium effects on column behavior, start-up analysis for a cascade, and preliminary experimental study on dependence of HETP on operational conditions. (author)

  7. Strengthing of Beams and Columns using GFRP Bars

    Science.gov (United States)

    Nayak, C. B.; Tade, M. K.; Thakare, S. B., Dr.

    2017-08-01

    Nowadays infrastructure development is raising its pace. Many reinforced high concrete and masonry buildings are constructed annually around the globe. There are large numbers of structures which deteriorate or become unsafe to use because of changes in use, changes in loading condition, change in the design configuration, inferior building material used or natural calamities. Thus repairing and retrofitting of these structures for safe usage of has a great market. There are several situations in which a civil structure would require strengthening due to lack of strength, stiffness, ductility and durability. Beams, columns may be strengthened in flexure by using GFRP in tension zone. In this present work comparative study will be made with and without GFRP circular bars in a beam and column. An experiment study will be carried out to study the change in the structural behavior of beams & columns with GFRP circular bars of different thickness, varying span to depth ratio.

  8. Spiral: a new equipment for exotic nuclei; Spiral: un nouvel equipement pour les noyaux exotiques

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-02-01

    This document presents the GANIL activities and more specially the SPIRAL project. The missions of the GANIL are to allow scientists fundamental researches in Nuclear Physics and to develop applications for heavy ions in other domains. Spiral is an european project, decided by NuPECC (NUclear Physics European Collaboration Committee). It is a first generation equipment allowing the production and the acceleration of light and moderately heavy nuclei at energy range of 2 to 25 MeV/nucleus. (A.L.B.)

  9. Reference frame for Product Configuration

    DEFF Research Database (Denmark)

    Ladeby, Klaes Rohde; Oddsson, Gudmundur Valur

    2011-01-01

    a reference frame for configuration that permits 1) a more precise understanding of a configuration system, 2) a understanding of how the configuration system relate to other systems, and 3) a definition of the basic concepts in configuration. The total configuration system, together with the definition...

  10. Remembering facial configurations.

    Science.gov (United States)

    Bruce, V; Doyle, T; Dench, N; Burton, M

    1991-02-01

    Eight experiments are reported showing that subjects can remember rather subtle aspects of the configuration of facial features to which they have earlier been exposed. Subjects saw several slightly different configurations (formed by altering the relative placement of internal features of the face) of each of ten different faces, and they were asked to rate the apparent age and masculinity-femininity of each. Afterwards, subjects were asked to select from pairs of faces the configuration which was identical to one previously rated. Subjects responded strongly to the central or "prototypical" configuration of each studied face where this was included as one member of each test pair, whether or not it had been studied (Experiments 1, 2 and 4). Subjects were also quite accurate at recognizing one of the previously encountered extremes of the series of configurations that had been rated (Experiment 3), but when unseen prototypes were paired with seen exemplars subjects' performance was at chance (Experiment 5). Prototype learning of face patterns was shown to be stronger than that for house patterns, though both classes of patterns were affected equally by inversion (Experiment 6). The final two experiments demonstrated that preferences for the prototype could be affected by instructions at study and by whether different exemplars of the same face were shown consecutively or distributed through the study series. The discussion examines the implications of these results for theories of the representation of faces and for instance-based models of memory.

  11. Nonlinear dynamics of breathers in the spiral structures of magnets

    Energy Technology Data Exchange (ETDEWEB)

    Kiselev, V. V., E-mail: kiselev@imp.uran.ru; Raskovalov, A. A. [Russian Academy of Sciences, Mikheev Institute of Metal Physics, Ural Branch (Russian Federation)

    2016-06-15

    The structure and properties of pulsating solitons (breathers) in the spiral structures of magnets are analyzed within the sine-Gordon model. The breather core pulsations are shown to be accompanied by local shifts and oscillations of the spiral structure with the formation of “precursors” and “tails” in the moving soliton. The possibilities for the observation and excitation of breathers in the spiral structures of magnets and multiferroics are discussed.

  12. Compression of interstellar clouds in spiral density-wave shocks

    International Nuclear Information System (INIS)

    Woodward, P.R.

    1979-01-01

    A mechanism of triggering star formation by galactic shocks is discussed. The possibilty that shocks may form along spiral arms in the gaseous component of a galactic disk is by now a familiar feature of spiral wave theory. It was suggested by Roberts (1969) that these shocks could trigger star formation in narrow bands forming a coherent spiral pattern over most of the disk of a galaxy. Some results of computer simulations of such a triggering process for star formation are reported. (Auth.)

  13. Cochlea and other spiral forms in nature and art.

    Science.gov (United States)

    Marinković, Slobodan; Stanković, Predrag; Štrbac, Mile; Tomić, Irina; Ćetković, Mila

    2012-01-01

    The original appearance of the cochlea and the specific shape of a spiral are interesting for both the scientists and artists. Yet, a correlation between the cochlea and the spiral forms in nature and art has been very rarely mentioned. The aim of this study was to investigate the possible correlation between the cochlea and the other spiral objects in nature, as well as the artistic presentation of the spiral forms. We explored data related to many natural objects and examined 13,625 artworks created by 2049 artists. We also dissected 2 human cochleas and prepared histologic slices of a rat cochlea. The cochlea is a spiral, cone-shaped osseous structure that resembles certain other spiral forms in nature. It was noticed that parts of some plants are arranged in a spiral manner, often according to Fibonacci numbers. Certain animals, their parts, or their products also represent various types of spirals. Many of them, including the cochlea, belong to the logarithmic type. Nature created spiral forms in the living world to pack a larger number of structures in a limited space and also to improve their function. Because the cochlea and other spiral forms have a certain aesthetic value, many artists presented them in their works of art. There is a mathematical and geometric correlation between the cochlea and natural spiral objects, and the same functional reason for their formation. The artists' imagery added a new aspect to those domains. Obviously, the creativity of nature and Homo sapiens has no limits--like the infinite distal part of the spiral. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Modeling and analysis of conventional and heat-integrated distillation columns

    DEFF Research Database (Denmark)

    Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens

    2015-01-01

    A generic model that can cover diabatic and adiabatic distillation column configurations is presented, with the aim ofproviding a consistent basis for comparison of alternative distillation column technologies. Both a static and a dynamic formulation of the model, together with a model catalogue...... consisting of the conventional, the heat-integrated and the mechanical vapor recompression distillation columns are presented. The solution procedure of the model is outlined and illustrated in three case studies. One case study being a benchmark study demonstrating the size of the model and the static...... properties of two different heat-integrated distillation column (HIDiC) schemes and the mechanical vapor recompression column. The second case study exemplifies the difference between a HIDiC and a conventional distillation column in the composition profiles within a multicomponent separation, whereas...

  15. Water Column Sonar Data Collection

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The collection and analysis of water column sonar data is a relatively new avenue of research into the marine environment. Primary uses include assessing biological...

  16. Diagnosis of pancreatic tumors by spiral angio CT

    International Nuclear Information System (INIS)

    Miura, Kohi; Nakao, Norio; Takayasu, Yukio; Okawa, Tomohisa

    1995-01-01

    Spiral angio were performed with injection of 30 ml of contrast material at a rate of 1 ml/sec with a scan delay of 6 sec through catheter into the celiac artery while the blood flow of the superior mesenteric artery (SMA) was occluded by the inflated balloon catheter. Spiral CT scans were obtained using Somatom Plus (Siemens). Parameter for spiral CT were 24-sec acquisition time, 5 mm collimation, 5 mm/sec table incrementation. Reconstructions were performed every 5 mm. Pancreatic cancers were characteristically depicted with spiral angio CT as hypodensity relative to normal enhanced pancreatic parenchyma. On dynamic angio CT studies performed in pancreatic cancers, the area of cancer and normal parenchyma had maximum level of enhancement at 10-15 sec after injection of contrast material via catheter into the celiac, and there was no difference in enhancement between tumor and normal parenchyma. On the other hand, the lesions of cancer were revealed as hypodensity with spiral angio CT. In case of chronic pancreatitis, the enhancement of the entire pancreas obtained with spiral angio CT was homogeneous. Insulinoma in the tail of pancreas was detected by spiral angio CT but was not detected by both selective angiography and conventional CT. Three-dimensional (3-D) rendering spiral angio CT data shows the extent of vascular involvement by pancreatic cancer and provides useful information for surgical planning. Spiral angio CT is the most useful procedure for diagnosis of pancreatic tumor. (author)

  17. SPIRAL2 Week 2012 - Slides of the presentations

    International Nuclear Information System (INIS)

    Staley, F.; Jacquemet, M.; Lewitowicz, M.; Bertrand, P.; Tuske, O.; Caruso, A.; Leyge, J.F.; Perrot, L.; Di Giacomo, M.; Ausset, P.; Moscatello, M.H.; Savalle, A.; Rannou, B.; Lambert, M.; Petit, E.; Hulin, X.; Barre-Boscher, N.; Tusseau-Nenez, S.; Tecchio, L.B.

    2013-01-01

    The main goal of the 5. edition of the SPIRAL2 Week is to present and discuss the current status of the SPIRAL2 project in front of a large community of scientists and engineers. The program of the meeting will include presentations on scientific and technical developments related to the baseline project, experiments and theory. The main topics to be discussed at the conference are: -) physics and detectors at SPIRAL2, -) driver accelerators, -) production of radioactive ion beams (RIB), -) safety, -) buildings and infrastructure, -) RIB facilities worldwide, and -) SPIRAL2 preparatory phase. This document is made up of the slides of the presentations

  18. Algorithms for computing efficient, electric-propulsion, spiralling trajectories

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop techniques for rapidly designing many-revolution, electric-propulsion, spiralling trajectories, including the effects of shadowing, gravity harmonics, and...

  19. On the nature of the ramified spiral structure of galaxies

    International Nuclear Information System (INIS)

    Mishurov, Yu.N.; Suchkov, A.A.

    1976-01-01

    The nature of large-scale branching of spiral arms observed in a number of galaxies has been explained in the framework of the density wave theory. The solutions of the dispersion equation of spiral waves of density relative to the wave number k(r) in the models of galaxies in the form of two discs rotating with different angular velocities have been shown to be branching functions of the parameter r (r is the galacto-centric distance) under definite conditions; it corresponds to the branching of spiral arms. Hydrodynamic and kinetic considerations are also presented. The last one makes possible the understanding several other structural properties of spiral galaxies

  20. Influence of excitability on unpinning and termination of spiral waves.

    Science.gov (United States)

    Luengviriya, Jiraporn; Sutthiopad, Malee; Phantu, Metinee; Porjai, Porramain; Kanchanawarin, Jarin; Müller, Stefan C; Luengviriya, Chaiya

    2014-11-01

    Application of electrical forcing to release pinned spiral waves from unexcitable obstacles and to terminate the rotation of free spiral waves at the boundary of excitable media has been investigated in thin layers of the Belousov-Zhabotinsky (BZ) reaction, prepared with different initial concentrations of H_{2}SO_{4}. Increasing [H_{2}SO_{4}] raises the excitability of the reaction and reduces the core diameter of free spiral waves as well as the wave period. An electric current with density stronger than a critical value Junpin causes a pinned spiral wave to drift away from the obstacle. For a given obstacle size, Junpin increases with [H_{2}SO_{4}]. Under an applied electrical current, the rotation center of a free spiral wave drifts along a straight path to the boundary. When the current density is stronger than a critical value Jterm, the spiral tip is forced to hit the boundary, where the spiral wave is terminated. Similar to Junpin for releasing a pinned spiral wave, Jterm also increases with [H_{2}SO_{4}]. These experimental findings were confirmed by numerical simulations using the Oregonator model, in which the excitability was adjusted via the ratio of the excitation rate to the recovery rate of the BZ reaction. Therefore, our investigation shows that decreasing the excitability can facilitate elimination of spiral waves by electrical forcing, either in the presence of obstacles or not.

  1. Configuration Control Office

    CERN Multimedia

    Beltramello, O

    In order to enable Technical Coordination to manage the detector configuration and to be aware of all changes in this configuration, a baseline of the envelopes has been created in April 2001. Fifteen system and multi-system envelope drawings have been approved and baselined. An EDMS file is associated with each approved envelope, which provides a list of the current known unsolved conflicts related to the envelope and a list of remaining drawing inconsistencies to be corrected. The envelope status with the associated drawings and EDMS file can be found on the web at this adress: http://atlasinfo.cern.ch/Atlas/TCOORD/Activities/Installation/Configuration/ Any modification in the baseline has to be requested via the Engineering Change Requests. The procedure can be found under: http://atlasinfo.cern.ch/Atlas/TCOORD/Activities/TcOffice/Quality/ECR/ TC will review all the systems envelopes in the near future and manage conflict resolution with the collaboration of the systems.

  2. The LHCb configuration database

    CERN Document Server

    Abadie, L; Van Herwijnen, Eric; Jacobsson, R; Jost, B; Neufeld, N

    2005-01-01

    The aim of the LHCb configuration database is to store information about all the controllable devices of the detector. The experiment's control system (that uses PVSS ) will configure, start up and monitor the detector from the information in the configuration database. The database will contain devices with their properties, connectivity and hierarchy. The ability to store and rapidly retrieve huge amounts of data, and the navigability between devices are important requirements. We have collected use cases to ensure the completeness of the design. Using the entity relationship modelling technique we describe the use cases as classes with attributes and links. We designed the schema for the tables using relational diagrams. This methodology has been applied to the TFC (switches) and DAQ system. Other parts of the detector will follow later. The database has been implemented using Oracle to benefit from central CERN database support. The project also foresees the creation of tools to populate, maintain, and co...

  3. LIQUID-LIQUID EXTRACTION COLUMNS

    Science.gov (United States)

    Thornton, J.D.

    1957-12-31

    This patent relates to liquid-liquid extraction columns having a means for pulsing the liquid in the column to give it an oscillatory up and down movement, and consists of a packed column, an inlet pipe for the dispersed liquid phase and an outlet pipe for the continuous liquid phase located in the direct communication with the liquid in the lower part of said column, an inlet pipe for the continuous liquid phase and an outlet pipe for the dispersed liquid phase located in direct communication with the liquid in the upper part of said column, a tube having one end communicating with liquid in the lower part of said column and having its upper end located above the level of said outlet pipe for the dispersed phase, and a piston and cylinder connected to the upper end of said tube for applying a pulsating pneumatic pressure to the surface of the liquid in said tube so that said surface rises and falls in said tube.

  4. Toward Cooling Uniformity: Investigation of Spiral, Sweeping Holes, and Unconventional Cooling Paradigms

    Science.gov (United States)

    Shyam, Vikram; Thurman, Douglas R.; Poinsatte, Philip E.; Ameri, Ali A.; Culley, Dennis E.

    2018-01-01

    Surface infrared thermography, hotwire anemometry, and thermocouple surveys were performed on two new film cooling hole geometries: spiral/rifled holes and fluidic sweeping holes. Ways to quantify the efficacy of novel cooling holes that are asymmetric, not uniformly spaced or that show variation from hole to hole are presented. The spiral holes attempt to induce large-scale vorticity to the film cooling jet as it exits the hole to prevent the formation of the kidney shaped vortices commonly associated with film cooling jets. The fluidic sweeping hole uses a passive in-hole geometry to induce jet sweeping at frequencies that scale with blowing ratios. The spiral hole performance is compared to that of round holes with and without compound angles. The fluidic hole is of the diffusion class of holes and is therefore compared to a 777 hole and square holes. A patent-pending spiral hole design showed the highest potential of the nondiffusion type hole configurations. Velocity contours and flow temperature were acquired at discreet cross-sections of the downstream flow field. The passive fluidic sweeping hole shows the most uniform cooling distribution but suffers from low span-averaged effectiveness levels due to enhanced mixing. The data was taken at a Reynolds number of 11,000 based on hole diameter and freestream velocity. Infrared thermography was taken for blowing ratios of 1.0, 1.5, 2.0, and 2.5 at a density ratio of 1.05. The flow inside the fluidic sweeping hole was studied using 3D unsteady RANS. A section on ideas for future work is included that addresses issues of quantifying cooling uniformity and provides some ideas for changing the way we think about cooling such as changing the direction of cooling or coupling acoustic devices to cooling holes to regulate frequency.

  5. Oxygen configurations in silica

    International Nuclear Information System (INIS)

    Chelikowsky, James R.; Chadi, D. J.; Binggeli, N.

    2000-01-01

    We propose a transition state for oxygen in silica. This state is produced by the insertion of an oxygen molecule into the Si-O-Si bond, i.e., it consists of producing a Si-O-O-O-Si bond. This state allows molecular oxygen diffusion in silica without breaking the molecular O 2 bond and it is energetically more stable than a peroxy configuration. This configuration may allow for exchange of molecular oxygen with the oxygen in the silica framework. (c) 2000 The American Physical Society

  6. Column-Oriented Database Systems (Tutorial)

    OpenAIRE

    Abadi, D.; Boncz, Peter; Harizopoulos, S.

    2009-01-01

    textabstractColumn-oriented database systems (column-stores) have attracted a lot of attention in the past few years. Column-stores, in a nutshell, store each database table column separately, with attribute values belonging to the same column stored contiguously, compressed, and densely packed, as opposed to traditional database systems that store entire records (rows) one after the other. Reading a subset of a table’s columns becomes faster, at the potential expense of excessive disk-head s...

  7. A Unified Scaling Law in Spiral Galaxies.

    Science.gov (United States)

    Koda; Sofue; Wada

    2000-03-01

    We investigate the origin of a unified scaling relation in spiral galaxies. Observed spiral galaxies are spread on a plane in the three-dimensional logarithmic space of luminosity L, radius R, and rotation velocity V. The plane is expressed as L~&parl0;VR&parr0;alpha in the I passband, where alpha is a constant. On the plane, observed galaxies are distributed in an elongated region which looks like the shape of a surfboard. The well-known scaling relations L-V (Tully-Fisher [TF] relation), V-R (also the TF relation), and R-L (Freeman's law) can be understood as oblique projections of the surfboard-like plane into two-dimensional spaces. This unified interpretation of the known scaling relations should be a clue to understand the physical origin of all the relations consistently. Furthermore, this interpretation can also explain why previous studies could not find any correlation between TF residuals and radius. In order to clarify the origin of this plane, we simulate formation and evolution of spiral galaxies with the N-body/smoothed particle hydrodynamics method, including cooling, star formation, and stellar feedback. Initial conditions are set to 14 isolated spheres with two free parameters, such as mass and angular momentum. The cold dark matter (h=0.5, Omega0=1) cosmology is considered as a test case. The simulations provide the following two conclusions: (1) The slope of the plane is well reproduced but the zero point is not. This zero-point discrepancy could be solved in a low-density (Omega00.5) cosmology. (2) The surfboard-shaped plane can be explained by the control of galactic mass and angular momentum.

  8. Energy savings in distillation via identification of useful configurations

    Science.gov (United States)

    Shah, Vishesh Hemanshu

    Recent market and environmental forces require the rapid development of better and cheaper separation process solutions. Especially for multicomponent mixtures, there are several feasible separation process solutions differing significantly in cost and energy consumption in spite of carrying out the same overall process. Therefore a systematic method to identify and design optimal multicomponent separation sequences is needed instead of relying on the inventive activity of a few experienced engineers. Even for a commonly perceived "mature" technology such as distillation, until recently there has been an absence of systematic methods to (i) elucidate all possible separation configurations and to (ii) identify energy efficient candidates. This research aims to address these needs. In this work, we focus on the continuous distillation of non-azeotropic mixtures into n distinct composition final product streams. We develop a computationally efficient and easy-to-use mathematical framework to generate all the basic distillation configurations that use exactly (n-1) distillation columns to carry out this n-component separation. We extend the framework to generate all the additional distillation configurations with thermal coupling. We observe that the search space of distillation configurations grows very rapidly as the number of product streams increases. For instance, for a mixture to be separated into 4 product streams, we can choose from 18 basic configurations and 134 additional configurations with thermal coupling; while for a mixture to be separated into 8 product streams, we can choose from 15,767,207 basic configurations and 29,006,926,681 additional configurations with thermal coupling. The next challenge for a process engineer is to be able to quickly prune the search space to a handful of attractive energy efficient candidates that can be studied in greater detail. To this effect, we develop a quick screening optimization tool that identifies configurations

  9. New compact cyclotron design for SPIRAL

    International Nuclear Information System (INIS)

    Duval, M.; Bourgarel, M.P.; Ripouteau, F.

    1995-01-01

    The SPIRAL project whose purpose is the production and the acceleration of radioactive nuclei is under realization at GANIL. The new facility uses a cyclotron as post accelerator taking place behind the present machine. The magnet structure is made of 4 independent return yokes and a common circular pole piece (3.5 m in diameter) with 4 sectors. The average induction needed is 1.56 Tesla with hill and valley gaps of respectively 0.12 and 0.3 m. The required field patterns are adjusted by means of circular trim coils located between the sectors and the pole piece. (author)

  10. Spiral Light Beams and Contour Image Processing

    Science.gov (United States)

    Kishkin, Sergey A.; Kotova, Svetlana P.; Volostnikov, Vladimir G.

    Spiral beams of light are characterized by their ability to remain structurally unchanged at propagation. They may have the shape of any closed curve. In the present paper a new approach is proposed within the framework of the contour analysis based on a close cooperation of modern coherent optics, theory of functions and numerical methods. An algorithm for comparing contours is presented and theoretically justified, which allows convincing of whether two contours are similar or not to within the scale factor and/or rotation. The advantages and disadvantages of the proposed approach are considered; the results of numerical modeling are presented.

  11. Controls and automation in the SPIRAL project

    International Nuclear Information System (INIS)

    Bothner, U.; Boulot, A.; Maherault, J.; Martial, L.

    1999-01-01

    The control and automation team of the R and D of Accelerator-Exotic Beam Department has had in the framework of SPIRAL collaboration the following tasks: 1. automation of the resonator high frequency equipment of the CIME cyclotron; 2. automation of the vacuum equipment, i.e. the low energy line (TBE), the CIME cyclotron, the low energy line (BE); 3. automation of load safety for power supply; 4. for each of these tasks a circuitry file based on the SCHEMA software has been worked out. The programs required in the automation of load safety for power supply (STEP5, PROTOOL, DESIGNER 4.1) were developed and implemented for PC

  12. Production and post acceleration scheme for spiral

    International Nuclear Information System (INIS)

    Bibet, D.

    2001-01-01

    SPIRAL, the R.I.B. facility of GANIL uses heavy ion beams to produce radioactive atoms inside a thick target. Atoms are ionised in a compact permanent magnet ECR ion source. The compact cyclotron CIME accelerates the radioactive ions in an energy range from 1.7 to 25 MeV/u. The cyclotron acts as a mass separator with resolving power of 2500. Plastic scintillator and silicon detectors are used to tune the machine at a very low intensity. An overview of the facility, stable beam tests results and the R and D program will be presented. (authors)

  13. Temperature simulations for the SPIRAL ISOL target

    International Nuclear Information System (INIS)

    Maunoury, L.; Bajeat, O.; Lichtenthaler, R.; Villari, A.C.C.

    2001-01-01

    Simulations of the power deposition and target temperature distributions in the SPIRAL ISOL target are presented. These simulations consider different heavy-ion beams with intensities corresponding to 2 and 6 kW on a carbon target. A new solutions, which corresponds to the splitting of the production target into two parts, where the first is cooled and the second is heated, allows keeping the overall size of the target ensemble relatively small. An extrapolation of the considered target geometry to primary beam intensities up to 1 MW is also presented. (authors)

  14. Galaxy Zoo: dust in spiral galaxies star

    OpenAIRE

    Masters, Karen L.; Nichol, Robert; Bamford, Steven; Mosleh, Moein; Lintott, Chris J.; Andreescu, Dan; Edmondson, Edward M.; Keel, William C.; Murray, Phil; Raddick, M. Jordan; Schawinski, Kevin; Slosar, Anze; Szalay, Alexander S.; Thomas, Daniel; Vandenberg, Jan

    2010-01-01

    We investigate the effect of dust on spiral galaxies by measuring the inclination dependence of optical colours for 24 276 well-resolved Sloan Digital Sky Survey (SDSS) galaxies visually classified via the Galaxy Zoo project. We find clear trends of reddening with inclination which imply a total extinction from face-on to edge-on of 0.7, 0.6, 0.5 and 0.4 mag for the ugri passbands (estimating 0.3 mag of extinction in z band). We split the sample into ‘bulgy’ (early-type) and ‘discy’ (late-typ...

  15. Stirling Engine Configuration Selection

    Directory of Open Access Journals (Sweden)

    Jose Egas

    2018-03-01

    Full Text Available Unlike internal combustion engines, Stirling engines can be designed to work with many drive mechanisms based on the three primary configurations, alpha, beta and gamma. Hundreds of different combinations of configuration and mechanical drives have been proposed. Few succeed beyond prototypes. A reason for poor success is the use of inappropriate configuration and drive mechanisms, which leads to low power to weight ratio and reduced economic viability. The large number of options, the lack of an objective comparison method, and the absence of a selection criteria force designers to make random choices. In this article, the pressure—volume diagrams and compression ratios of machines of equal dimensions, using the main (alpha, beta and gamma crank based configurations as well as rhombic drive and Ross yoke mechanisms, are obtained. The existence of a direct relation between the optimum compression ratio and the temperature ratio is derived from the ideal Stirling cycle, and the usability of an empirical low temperature difference compression ratio equation for high temperature difference applications is tested using experimental data. It is shown that each machine has a different compression ratio, making it more or less suitable for a specific application, depending on the temperature difference reachable.

  16. Global Value Chain Configuration

    DEFF Research Database (Denmark)

    Hernandez, Virginia; Pedersen, Torben

    2017-01-01

    modes chosen and the different ways of coordinating them. We also examine the outcomes of a global value chain configuration in terms of performance and upgrading. Our aim is to review the state of the art of these issues, identify research gaps and suggest new lines for future research that would...

  17. Inclusive Services Innovation Configuration

    Science.gov (United States)

    Holdheide, Lynn R.; Reschly, Daniel J.

    2011-01-01

    Teacher preparation to deliver inclusive services to students with disabilities is increasingly important because of changes in law and policy emphasizing student access to, and achievement in, the general education curriculum. This innovation configuration identifies the components of inclusive services that should be incorporated in teacher…

  18. Ansible configuration management

    CERN Document Server

    Hall, Daniel

    2015-01-01

    This book is intended for anyone who wants to learn Ansible starting from the basics. Some experience of how to set up and configure Linux machines and a working knowledge of BIND, MySQL, and other Linux daemons is expected.

  19. Planet-driven Spiral Arms in Protoplanetary Disks. II. Implications

    Science.gov (United States)

    Bae, Jaehan; Zhu, Zhaohuan

    2018-06-01

    We examine whether various characteristics of planet-driven spiral arms can be used to constrain the masses of unseen planets and their positions within their disks. By carrying out two-dimensional hydrodynamic simulations varying planet mass and disk gas temperature, we find that a larger number of spiral arms form with a smaller planet mass and a lower disk temperature. A planet excites two or more spiral arms interior to its orbit for a range of disk temperatures characterized by the disk aspect ratio 0.04≤slant {(h/r)}p≤slant 0.15, whereas exterior to a planet’s orbit multiple spiral arms can form only in cold disks with {(h/r)}p≲ 0.06. Constraining the planet mass with the pitch angle of spiral arms requires accurate disk temperature measurements that might be challenging even with ALMA. However, the property that the pitch angle of planet-driven spiral arms decreases away from the planet can be a powerful diagnostic to determine whether the planet is located interior or exterior to the observed spirals. The arm-to-arm separations increase as a function of planet mass, consistent with previous studies; however, the exact slope depends on disk temperature as well as the radial location where the arm-to-arm separations are measured. We apply these diagnostics to the spiral arms seen in MWC 758 and Elias 2–27. As shown in Bae et al., planet-driven spiral arms can create concentric rings and gaps, which can produce a more dominant observable signature than spiral arms under certain circumstances. We discuss the observability of planet-driven spiral arms versus rings and gaps.

  20. Radiotracer Imaging of Sediment Columns

    Science.gov (United States)

    Moses, W. W.; O'Neil, J. P.; Boutchko, R.; Nico, P. S.; Druhan, J. L.; Vandehey, N. T.

    2010-12-01

    Nuclear medical PET and SPECT cameras routinely image radioactivity concentration of gamma ray emitting isotopes (PET - 511 keV; SPECT - 75-300 keV). We have used nuclear medical imaging technology to study contaminant transport in sediment columns. Specifically, we use Tc-99m (T1/2 = 6 h, Eγ = 140 keV) and a SPECT camera to image the bacteria mediated reduction of pertechnetate, [Tc(VII)O4]- + Fe(II) → Tc(IV)O2 + Fe(III). A 45 mL bolus of Tc-99m (32 mCi) labeled sodium pertechnetate was infused into a column (35cm x 10cm Ø) containing uranium-contaminated subsurface sediment from the Rifle, CO site. A flow rate of 1.25 ml/min of artificial groundwater was maintained in the column. Using a GE Millennium VG camera, we imaged the column for 12 hours, acquiring 44 frames. As the microbes in the sediment were inactive, we expected most of the iron to be Fe(III). The images were consistent with this hypothesis, and the Tc-99m pertechnetate acted like a conservative tracer. Virtually no binding of the Tc-99m was observed, and while the bolus of activity propagated fairly uniformly through the column, some inhomogeneity attributed to sediment packing was observed. We expect that after augmentation by acetate, the bacteria will metabolically reduce Fe(III) to Fe(II), leading to significant Tc-99m binding. Imaging sediment columns using nuclear medicine techniques has many attractive features. Trace quantities of the radiolabeled compounds are used (micro- to nano- molar) and the half-lives of many of these tracers are short (Image of Tc-99m distribution in a column containing Rifle sediment at four times.

  1. SELF-DESTRUCTING SPIRAL WAVES: GLOBAL SIMULATIONS OF A SPIRAL-WAVE INSTABILITY IN ACCRETION DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Jaehan; Hartmann, Lee [Department of Astronomy, University of Michigan, 1085 S. University Ave., Ann Arbor, MI 48109 (United States); Nelson, Richard P.; Richard, Samuel, E-mail: jaehbae@umich.edu, E-mail: lhartm@umich.edu, E-mail: r.p.nelson@qmul.ac.uk, E-mail: samuel.richard@qmul.ac.uk [Astronomy Unit, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom)

    2016-09-20

    We present results from a suite of three-dimensional global hydrodynamic simulations that shows that spiral density waves propagating in circumstellar disks are unstable to the growth of a parametric instability that leads to break down of the flow into turbulence. This spiral wave instability (SWI) arises from a resonant interaction between pairs of inertial waves, or inertial-gravity waves, and the background spiral wave. The development of the instability in the linear regime involves the growth of a broad spectrum of inertial modes, with growth rates on the order of the orbital time, and results in a nonlinear saturated state in which turbulent velocity perturbations are of a similar magnitude to those induced by the spiral wave. The turbulence induces angular momentum transport and vertical mixing at a rate that depends locally on the amplitude of the spiral wave (we obtain a stress parameter α ∼ 5 × 10{sup −4} in our reference model). The instability is found to operate in a wide range of disk models, including those with isothermal or adiabatic equations of state, and in viscous disks where the dimensionless kinematic viscosity ν ≤ 10{sup −5}. This robustness suggests that the instability will have applications to a broad range of astrophysical disk-related phenomena, including those in close binary systems, planets embedded in protoplanetary disks (including Jupiter in our own solar system) and FU Orionis outburst models. Further work is required to determine the nature of the instability and to evaluate its observational consequences in physically more complete disk models than we have considered in this paper.

  2. SELF-DESTRUCTING SPIRAL WAVES: GLOBAL SIMULATIONS OF A SPIRAL-WAVE INSTABILITY IN ACCRETION DISKS

    International Nuclear Information System (INIS)

    Bae, Jaehan; Hartmann, Lee; Nelson, Richard P.; Richard, Samuel

    2016-01-01

    We present results from a suite of three-dimensional global hydrodynamic simulations that shows that spiral density waves propagating in circumstellar disks are unstable to the growth of a parametric instability that leads to break down of the flow into turbulence. This spiral wave instability (SWI) arises from a resonant interaction between pairs of inertial waves, or inertial-gravity waves, and the background spiral wave. The development of the instability in the linear regime involves the growth of a broad spectrum of inertial modes, with growth rates on the order of the orbital time, and results in a nonlinear saturated state in which turbulent velocity perturbations are of a similar magnitude to those induced by the spiral wave. The turbulence induces angular momentum transport and vertical mixing at a rate that depends locally on the amplitude of the spiral wave (we obtain a stress parameter α ∼ 5 × 10 −4 in our reference model). The instability is found to operate in a wide range of disk models, including those with isothermal or adiabatic equations of state, and in viscous disks where the dimensionless kinematic viscosity ν ≤ 10 −5 . This robustness suggests that the instability will have applications to a broad range of astrophysical disk-related phenomena, including those in close binary systems, planets embedded in protoplanetary disks (including Jupiter in our own solar system) and FU Orionis outburst models. Further work is required to determine the nature of the instability and to evaluate its observational consequences in physically more complete disk models than we have considered in this paper.

  3. Performance evaluation of a rectifier column using gamma column scanning

    Directory of Open Access Journals (Sweden)

    Aquino Denis D.

    2017-12-01

    Full Text Available Rectifier columns are considered to be a critical component in petroleum refineries and petrochemical processing installations as they are able to affect the overall performance of these facilities. It is deemed necessary to monitor the operational conditions of such vessels to optimize processes and prevent anomalies which could pose undesired consequences on product quality that might lead to huge financial losses. A rectifier column was subjected to gamma scanning using a 10-mCi Co-60 source and a 2-inch-long detector in tandem. Several scans were performed to gather information on the operating conditions of the column under different sets of operating parameters. The scan profiles revealed unexpected decreases in the radiation intensity at vapour levels between trays 2 and 3, and between trays 4 and 5. Flooding also occurred during several scans which could be attributed to parametric settings.

  4. Post column derivatisation analyses review. Is post-column derivatisation incompatible with modern HPLC columns?

    Science.gov (United States)

    Jones, Andrew; Pravadali-Cekic, Sercan; Dennis, Gary R; Shalliker, R Andrew

    2015-08-19

    Post Column derivatisation (PCD) coupled with high performance liquid chromatography or ultra-high performance liquid chromatography is a powerful tool in the modern analytical laboratory, or at least it should be. One drawback with PCD techniques is the extra post-column dead volume due to reaction coils used to enable adequate reaction time and the mixing of reagents which causes peak broadening, hence a loss of separation power. This loss of efficiency is counter-productive to modern HPLC technologies, -such as UHPLC. We reviewed 87 PCD methods published from 2009 to 2014. We restricted our review to methods published between 2009 and 2014, because we were interested in the uptake of PCD methods in UHPLC environments. Our review focused on a range of system parameters including: column dimensions, stationary phase and particle size, as well as the geometry of the reaction loop. The most commonly used column in the methods investigated was not in fact a modern UHPLC version with sub-2-micron, (or even sub-3-micron) particles, but rather, work-house columns, such as, 250 × 4.6 mm i.d. columns packed with 5 μm C18 particles. Reaction loops were varied, even within the same type of analysis, but the majority of methods employed loop systems with volumes greater than 500 μL. A second part of this review illustrated briefly the effect of dead volume on column performance. The experiment evaluated the change in resolution and separation efficiency of some weak to moderately retained solutes on a 250 × 4.6 mm i.d. column packed with 5 μm particles. The data showed that reaction loops beyond 100 μL resulted in a very serious loss of performance. Our study concluded that practitioners of PCD methods largely avoid the use of UHPLC-type column formats, so yes, very much, PCD is incompatible with the modern HPLC column. Copyright © 2015. Published by Elsevier B.V.

  5. Propulsion using the electron spiral toroid

    International Nuclear Information System (INIS)

    Seward, Clint

    1998-01-01

    A new propulsion method is proposed which could potentially reduce propellant needed for space travel by three orders of magnitude. It uses the newly patented electron spiral toroid (EST), which stores energy as magnetic field energy. The EST is a hollow toroid of electrons, all spiraling in parallel paths in a thin outer shell. The electrons satisfy the coupling condition, forming an electron matrix. Stability is assured as long as the coupling condition is satisfied. The EST is held in place with a small external electric field; without an external magnetic field. The EST system is contained in a vacuum chamber. The EST can be thought of as an energetic entity, with electrons at 10,000 electron volts. Propulsion would not use combustion, but would heat propellant through elastic collisions with the EST surface and eject them for thrust. Chemical rocket combustion heats propellant to 4000 deg. C; an EST will potentially heat the propellant 29,000 times as much, reducing propellant needs accordingly. The thrust can be turned ON and OFF. The EST can be recharged as needed

  6. Optimising imaging parameters in experimental spiral CT

    International Nuclear Information System (INIS)

    Tiitola, M.; Vehmas, T.; Kivisaari, R.P.; Kivisaari, L.

    1997-01-01

    Purpose: This in vitro study was conducted to analyse lesion detection and relative radiation exposure in different CT techniques. Material and Methods: We used a plastic phantom (12 x 8 x 2 cm) containing holes filled with air or fluid of varying densities to simulate lesions. This was imaged with Siemens Somatom Plus S and GE High Speed Advantage units. We varied table feeds (3 and 6 mm/s in Siemens and 3 and 4.5 mm/s in GE) and increments (2 mm and 4 mm) while keeping collimation at 3 mm. The SmartScan program of GE and the reformating algorithm of Siemens were also analysed. To evaluate the different methods, the phatnom lesions were counted by 3 observers. Radiation exposures associated with each technique were also measured. Results: The images reformatted to a coronal direction were significantly inferior (p<0.01) to those in other techniques. The use of SmartScan did not influence lesion detection, nor did changes in pitch or increment. Spiral and non-spiral techniques proved to be equal. Radiation exposure was lowest when a greater pitch or the SmartScan program was used. Conclusion: Radiation exposure in CT can be limited without significantly impairing the image quality by using low-dose techniques. Reformatting to a coronal direction should be used with care as it debases the image quality. (orig.)

  7. Spiral-shaped reactor for water disinfection

    KAUST Repository

    Soukane, Sofiane

    2016-04-20

    Chlorine-based processes are still widely used for water disinfection. The disinfection process for municipal water consumption is usually carried out in large tanks, specifically designed to verify several hydraulic and disinfection criteria. The hydrodynamic behavior of contact tanks of different shapes, each with an approximate total volume of 50,000 m3, was analyzed by solving turbulent momentum transport equations with a computational fluid dynamics code, namely ANSYS fluent. Numerical experiments of a tracer pulse were performed for each design to generate flow through curves and investigate species residence time distribution for different inlet flow rates, ranging from 3 to 12 m3 s−1. A new nature-inspired Conch tank design whose shape follows an Archimedean spiral was then developed. The spiral design is shown to strongly outperform the other tanks’ designs for all the selected plug flow criteria with an enhancement in efficiency, less short circuiting, and an order of magnitude improvement in mixing and dispersion. Moreover, following the intensification philosophy, after 50% reduction in its size, the new design retains its properties and still gives far better results than the classical shapes.

  8. Model for Spiral Galaxys Rotation Curves

    Science.gov (United States)

    Hodge, John

    2003-11-01

    A model of spiral galaxy dynamics is proposed. An expression describing the rotation velocity of particles v in a galaxy as a function of the distance from the center r (RC) is developed. The resulting, intrinsic RC of a galaxy is Keplerian in the inner bulge and rising in the disk region without modifying the Newtonian gravitational potential (MOND) and without unknown dark matter. The v^2 is linearly related to r of the galaxy in part of the rapidly rising region of the HI RC (RRRC) and to r^2 in another part of the RRRC. The r to discontinuities in the surface brightness versus r curve is related to the 21 cm line width, the measured mass of the central supermassive black hole (SBH), and the maximum v^2 in the RRRC. The distance to spiral galaxies can be calculated from these relationships that tightly correlates with the distance calculated using Cepheid variables. Differing results in measuring the mass of the SBH from differing measurement procedures are explained. This model is consistent with previously unexplained data, has predicted new relationships, and suggests a new model of the universe. Full text: http://web.infoave.net/ ˜scjh.

  9. Stellar complexes in spiral arms of galaxies

    Science.gov (United States)

    Efremov, Yu. N.

    The history of the introduction and development of the star complexes conception is briefly described. These large groups of stars were picked out and named as such ones in our Galaxy with argumentation and evidence for their physical unity (using the Cepheid variables the distances and ages of which are easy determined from their periods); anyway earlier the complexes were noted along the spiral arms of the Andromeda galaxy, but were not recognized as a new kind of star group. The chains of complexes along the spiral arms are observed quite rarely; their origin is explained by magneto- gravitational or purely gravitational instability developing along the arm. It is not clear why these chains are quite a rare phenomenon - and more so why sometimes the regular chain of complexes are observed in one arm only. Probably intergalactic magnetic field participated in formation of such chains. Apart from the complexes located along the arms, there are isolated giant complexes known (up to 700 pc in diameter) which look like super-gigantic but rather rarefied globular clusters. Until now only two of these formations are studied, in NGC 6946 and M51.

  10. Spiral blood flow in aorta-renal bifurcation models.

    Science.gov (United States)

    Javadzadegan, Ashkan; Simmons, Anne; Barber, Tracie

    2016-01-01

    The presence of a spiral arterial blood flow pattern in humans has been widely accepted. It is believed that this spiral component of the blood flow alters arterial haemodynamics in both positive and negative ways. The purpose of this study was to determine the effect of spiral flow on haemodynamic changes in aorta-renal bifurcations. In this regard, a computational fluid dynamics analysis of pulsatile blood flow was performed in two idealised models of aorta-renal bifurcations with and without flow diverter. The results show that the spirality effect causes a substantial variation in blood velocity distribution, while causing only slight changes in fluid shear stress patterns. The dominant observed effect of spiral flow is on turbulent kinetic energy and flow recirculation zones. As spiral flow intensity increases, the rate of turbulent kinetic energy production decreases, reducing the region of potential damage to red blood cells and endothelial cells. Furthermore, the recirculation zones which form on the cranial sides of the aorta and renal artery shrink in size in the presence of spirality effect; this may lower the rate of atherosclerosis development and progression in the aorta-renal bifurcation. These results indicate that the spiral nature of blood flow has atheroprotective effects in renal arteries and should be taken into consideration in analyses of the aorta and renal arteries.

  11. A comment on spiral motions in projective relativity

    International Nuclear Information System (INIS)

    Muzzio, J.C.; Lousto, C.O.; Instituto de Astronomia y Fisica del Espacio de la Republica Argentina)

    1985-01-01

    Astronomical evidence has been inadequately invoked to support projective relativity. The spiral structure cannot be explained just by the existence of spiral orbits, and the use of Oort's constant to support the theory is also a misunderstanding. Besides, some mathematical inaccuracies make the application invalid. (author)

  12. Drift of Spiral Waves in Complex Ginzburg-Landau Equation

    International Nuclear Information System (INIS)

    Yang Junzhong; Zhang Mei

    2006-01-01

    The spontaneous drift of the spiral wave in a finite domain in the complex Ginzburg-Landau equation is investigated numerically. By using the interactions between the spiral wave and its images, we propose a phenomenological theory to explain the observations.

  13. Strained spiral vortex model for turbulent fine structure

    Science.gov (United States)

    Lundgren, T. S.

    1982-01-01

    A model for the intermittent fine structure of high Reynolds number turbulence is proposed. The model consists of slender axially strained spiral vortex solutions of the Navier-Stokes equation. The tightening of the spiral turns by the differential rotation of the induced swirling velocity produces a cascade of velocity fluctuations to smaller scale. The Kolmogorov energy spectrum is a result of this model.

  14. Nonuniqueness of self-propagating spiral galaxy models

    International Nuclear Information System (INIS)

    Freedman, W.L.; Madore, B.F.

    1984-01-01

    We demonstrate the nonuniqueness of the basic assumptions leading to spiral structure in self-propagating star formation models. Even in the case where star formation occurs purely spontaneously and does not propagate, we have generated spiral structure by adopting the radically different assumption where star formation is systematically inhibited

  15. A Fundamental Plane of Spiral Structure in Disk Galaxies

    NARCIS (Netherlands)

    Davis, Benjamin L.; Kennefick, Daniel; Kennefick, Julia; Westfall, Kyle B.; Shields, Douglas W.; Flatman, Russell; Hartley, Matthew T.; Berrier, Joel C.; Martinsson, Thomas P. K.; Swaters, Rob A.

    Spiral structure is the most distinctive feature of disk galaxies and yet debate persists about which theory of spiral structure is correct. Many versions of the density wave theory demand that the pitch angle be uniquely determined by the distribution of mass in the bulge and disk of the galaxy. We

  16. Profiles of the stochastic star formation process in spiral galaxies

    International Nuclear Information System (INIS)

    Comins, N.

    1981-01-01

    The formation of spiral arms in disc galaxies is generally attributed to the effects of spiral density waves. These relatively small (i.e. 5 per cent) non-axisymmetric perturbations of the interstellar medium cause spiral arms highlighted by O and B type stars to be created. In this paper another mechanism for spiral arm formation, the stochastic self-propagating star formation (SSPSF) process is examined. The SSPSF process combines the theory that shock waves from supernovae will compress the interstellar medium to create new stars, some of which will be massive enough to also supernova, with a disc galaxy's differential rotation to create spiral arms. The present work extends this process to the case where the probability of star formation from supernova shocks decreases with galactic radius. Where this work and previous investigations overlap (namely the uniform probability case), the agreement is very good, pretty spirals with various numbers of arms are generated. The decreasing probability cases, taken to vary as rsup(-j), still form spiral arms for 0 1.5 the spiral structure is essentially non-existent. (author)

  17. The cold interstellar medium - An HI view of spiral galaxies

    NARCIS (Netherlands)

    Sancisi, R; Bender, R; Davies, RL

    1996-01-01

    An HI view of spiral galaxies is presented. In the first part the standard picture of isolated, normal spiral galaxies is briefly reviewed. In the second part attention is drawn to all those phenomena, such as tidal interactions, accretion and mergers, that depend on the galaxy environment and seem

  18. Star formation and the surface brightness of spiral galaxies

    International Nuclear Information System (INIS)

    Phillipps, S.; Disney, M.

    1985-01-01

    The (blue) surface brightness of spiral galaxies is significantly correlated with their Hα linewidth. This can be most plausibly interpreted as a correlation of surface brightness with star formation rate. There is also a significant difference in surface brightness between galaxies forming stars in a grand design spiral pattern and those with floc star formation regions. (author)

  19. Up the Down Spiral with English: Guidelines, Project Insight.

    Science.gov (United States)

    Catholic Board of Education, Diocese of Cleveland, OH.

    This curriculum guide presents the philosophy, objectives, and processes which unify a student-centered English program based on Jerome Bruner's concept of the spiral curriculum. To illustrate the spiraling of the learning process (i.e., engagement, perception, interpretation, evaluation, and personal integration), the theme of "hero" is traced…

  20. Stress-Strain Relationship of Synthetic Fiber Reinforced Concrete Columns

    Directory of Open Access Journals (Sweden)

    Rosidawani

    2017-01-01

    Full Text Available Many empirical confinement models for normal and high strength concrete have been developed. Nevertheless, reported studies in the term of confinement of fiber reinforced concrete are limited. Whereas, the use of fiber reinforced concrete in structural elements has become the subject of the research and has indicated positive experiences. Since the stress-strain relationship of concrete in compression is required for analysis of structural members, the study of the stress-strain relationship for synthetic fiber reinforced concrete is substantial. The aim of the study is to examine the capabilities of the various models available in the literature to predict the actual experimental behavior of synthetic fiber reinforced high-strength concrete columns. The experimental data used are the results of the circular column specimens with the spiral spacing and the volume fraction of synthetic fiber as the test variables. The axial stress-strain curves from the tests are then compared with the various models of confinement from the literature. The performance index of each model is measured by using the coefficient of variation (COV concept of stress and strain behavior parameter. Among the confinement models, Cusson model shows the closest valid value of the coefficient of variation.

  1. NOx retention in scrubbing column

    International Nuclear Information System (INIS)

    Nakazone, A.K.; Costa, R.E.; Lobao, A.S.T.; Matsuda, H.T.; Araujo, B.F.

    1988-07-01

    During the UO 2 dissolution in nitric acid, some different species of NO x are released. The off gas can either be refluxed to the dissolver or be released and retained on special columns. The final composition of the solution is the main parameter to take in account. A process for nitrous gases retention using scubber columns containing H 2 O or diluted HNO 3 is presented. Chemiluminescence measurement was employed to NO x evalution before and after scrubbing. Gas flow, temperature, residence time are the main parameters considered in this paper. For the dissolution of 100g UO 2 in 8M nitric acid, a 6NL/h O 2 flow was the best condition for the NO/NO 2 oxidation with maximum adsorption in the scrubber columns. (author) [pt

  2. Topographic Beta Spiral and Onshore Intrusion of the Kuroshio Current

    Science.gov (United States)

    Yang, De-Zhou; Huang, Rui Xin; Yin, Bao-shu; Feng, Xing-Ru; Chen, Hai-ying; Qi, Ji-Feng; Xu, Ling-jing; Shi, Yun-long; Cui, Xuan; Gao, Guan-Dong; Benthuysen, Jessica A.

    2018-01-01

    The Kuroshio intrusion plays a vitally important role in carrying nutrients to marginal seas. However, the key mechanism leading to the Kuroshio intrusion remains unclear. In this study we postulate a mechanism: when the Kuroshio runs onto steep topography northeast of Taiwan, the strong inertia gives rise to upwelling over topography, leading to a left-hand spiral in the stratified ocean. This is called the topographic beta spiral, which is a major player regulating the Kuroshio intrusion; this spiral can be inferred from hydrographic surveys. In the world oceans, the topographic beta spirals can be induced by upwelling generated by strong currents running onto steep topography. This is a vital mechanism regulating onshore intruding flow and the cross-shelf transport of energy and nutrients from the Kuroshio Current to the East China Sea. This topographic beta spiral reveals a long-term missing link between the oceanic general circulation theory and shelf dynamic theory.

  3. Spatial and mass distributions of molecular clouds and spiral structure

    International Nuclear Information System (INIS)

    Kwan, J.; Valdes, F.; National Optical Astronomy Observatories, Tucson, AZ)

    1987-01-01

    The growth of molecular clouds resulting from cloud-cloud collisions and coalescence in the Galactic ring between 4 and 8 kpc are modeled, taking into account the presence of a spiral potential and the mutual cloud-cloud gravitational attraction. The mean lifetime of molecular clouds is determined to be about 200 million years. The clouds are present in both spiral arm and interarm regions, but a spiral pattern in their spatial distribution is clearly discernible, with the more massive clouds showing a stronger correlation with the spiral arms. As viewed from within the Galactic disk, however, it is very difficult to ascertain that the molecular cloud distribution in longitude-velocity space has a spiral pattern. 19 references

  4. Suppression of Spiral Wave in Modified Orengonator Model

    International Nuclear Information System (INIS)

    Ma Jun; Wang Chunni; Jin Wuyin; Yi Ming

    2008-01-01

    In this paper, a spatial perturbation scheme is proposed to suppress the spiral wave in the modified Orengonator model, which is used to describe the chemical reaction in the light-sensitive media. The controllable external illumination Φ is perturbed with a spatial linear function. In our numerical simulation, the scheme is investigated by imposing the external controllable illumination on the space continuously and/or intermittently. The numerical simulation results confirm that the stable rotating spiral wave still can be removed with the scheme proposed in this paper even if the controllable Φ changed vs. time and space synchronously. Then the scheme is also used to control the spiral wave and turbulence in the modified Fitzhugh-Nagumo model. It is found that the scheme is effective to remove the sable rotating and meandering spiral wave but it costs long transient period and intensity of the gradient parameter to eliminate the spiral turbulence

  5. Neutral hydrogen and spiral structure in M33

    International Nuclear Information System (INIS)

    Newton, K.

    1980-01-01

    Observations of neutral hydrogen (H I) in the galaxy M33 are presented which have sufficient angular resolution (47 x 93 arcsec) to distinguish detailed H I spiral structure for the first time. H I spiral features extend over the entire disc; the pattern is broken and multi-armed with the best-defined arms lying at radii outside the brightest optical features. Several very narrow spiral 'filaments' are unresolved by the beam, implying true widths -1 , is perturbed near the inner spiral arms. These perturbations agree with the predictions of density-wave theory but may simply arise from the self-gravity of massive arms whether or not they are a quasi-stationary wave phenomenon. If the outer spiral features form a rigidly rotating density-wave pattern, the absence of large radial streaming motions along the features implies a small pattern speed ( -1 kpc -1 ), with corotation in the outer parts of the disc. (author)

  6. A FUNDAMENTAL PLANE OF SPIRAL STRUCTURE IN DISK GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Benjamin L.; Kennefick, Daniel; Kennefick, Julia; Shields, Douglas W. [Arkansas Center for Space and Planetary Sciences, University of Arkansas, 346 1/2 North Arkansas Avenue, Fayetteville, AR 72701 (United States); Westfall, Kyle B. [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, NL-9700 AV Groningen (Netherlands); Flatman, Russell [School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, GA 30332 (United States); Hartley, Matthew T. [Department of Physics, University of Arkansas, 226 Physics Building, 835 West Dickson Street, Fayetteville, AR 72701 (United States); Berrier, Joel C. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854-8019 (United States); Martinsson, Thomas P. K. [Leiden Observatory, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Swaters, Rob A., E-mail: bld002@email.uark.edu [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)

    2015-03-20

    Spiral structure is the most distinctive feature of disk galaxies and yet debate persists about which theory of spiral structure is correct. Many versions of the density wave theory demand that the pitch angle be uniquely determined by the distribution of mass in the bulge and disk of the galaxy. We present evidence that the tangent of the pitch angle of logarithmic spiral arms in disk galaxies correlates strongly with the density of neutral atomic hydrogen in the disk and with the central stellar bulge mass of the galaxy. These three quantities, when plotted against each other, form a planar relationship that we argue should be fundamental to our understanding of spiral structure in disk galaxies. We further argue that any successful theory of spiral structure must be able to explain this relationship.

  7. Symmetries of cluster configurations

    International Nuclear Information System (INIS)

    Kramer, P.

    1975-01-01

    A deeper understanding of clustering phenomena in nuclei must encompass at least two interrelated aspects of the subject: (A) Given a system of A nucleons with two-body interactions, what are the relevant and persistent modes of clustering involved. What is the nature of the correlated nucleon groups which form the clusters, and what is their mutual interaction. (B) Given the cluster modes and their interaction, what systematic patterns of nuclear structure and reactions emerge from it. Are there, for example, families of states which share the same ''cluster parents''. Which cluster modes are compatible or exclude each other. What quantum numbers could characterize cluster configurations. There is no doubt that we can learn a good deal from the experimentalists who have discovered many of the features relevant to aspect (B). Symmetries specific to cluster configurations which can throw some light on both aspects of clustering are discussed

  8. Analyzing Visibility Configurations.

    Science.gov (United States)

    Dachsbacher, C

    2011-04-01

    Many algorithms, such as level of detail rendering and occlusion culling methods, make decisions based on the degree of visibility of an object, but do not analyze the distribution, or structure, of the visible and occluded regions across surfaces. We present an efficient method to classify different visibility configurations and show how this can be used on top of existing methods based on visibility determination. We adapt co-occurrence matrices for visibility analysis and generalize them to operate on clusters of triangular surfaces instead of pixels. We employ machine learning techniques to reliably classify the thus extracted feature vectors. Our method allows perceptually motivated level of detail methods for real-time rendering applications by detecting configurations with expected visual masking. We exemplify the versatility of our method with an analysis of area light visibility configurations in ray tracing and an area-to-area visibility analysis suitable for hierarchical radiosity refinement. Initial results demonstrate the robustness, simplicity, and performance of our method in synthetic scenes, as well as real applications.

  9. Mechanical configuration and maintenance

    International Nuclear Information System (INIS)

    Brown, T.G.; Casini, G.; Churakov, G.F.

    1982-01-01

    The INTOR engineering design has been strongly influenced by considerations for assembly and maintenance. A maintenance philosophy was established at the outset of the conceptual design to insure that the tokamak configuration would be developed to accommodate maintenance requirements. The main features of the INTOR design are summarized in this paper with primary emphasis on the impact of maintenance considerations. The most apparent configuration design feature is the access provided for torus maintenance. Particular attention was given to the size and location of superconducting magnets and the location of vacuum boundaries. All of the poloidal field (PF) coils are placed outside of the bore of the toroidal field (TF) coils and located above and below an access opening between adjacent TF coils through which torus sectors are removed. A magnet structural configuration consisting of mechanically attached reinforcing members has been designed which facilitates the open access space for torus sector removal. For impurity control, a single null poloidal divertor was selected over a double null design in order to maintain sufficient access for pumping and maintenance of the collector. A double null divertor was found to severely limit access to the torus with the addition of divertor collectors and pumping at the top. For this reason, a single null concept was selected in spite of the more difficult design problems associated with the required asymmetric PF system and higher particle loadings

  10. Imaging of head and neck tumors -- methods: CT, spiral-CT, multislice-spiral-CT

    International Nuclear Information System (INIS)

    Baum, Ulrich; Greess, Holger; Lell, Michael; Noemayr, Anton; Lenz, Martin

    2000-01-01

    Spiral-CT is standard for imaging neck tumors. In correspondence with other groups we routinely use spiral-CT with thin slices (3 mm), a pitch of 1.3-1.5 and an overlapping reconstruction increment (2-3 mm). In patients with dental fillings a short additional spiral parallel to the corpus of the mandible reduces artifacts behind the dental arches and improves the diagnostic value of CT. For the assessment of the base of the skull, the orbital floor, the palate and paranasal sinuses an additional examination in the coronal plane is helpful. Secondary coronal reconstructions of axial scans are helpful in the evaluation of the crossing of the midline by small tumors of the tongue base or palate. For an optimal vascular or tissue contrast a sufficient volume of contrast medium and a start delay greater than 70-80 s are necessary. In our opinion the best results can be achieved with a volume of 150 ml, a flow of 2.5 ml/s and a start delay of 80 s. Dynamic enhanced CT is only necessary in some special cases. There is clear indication for dynamic enhanced CT where a glomus tumor is suspected. Additional functional CT imaging during i-phonation and/or Valsalva's maneuver are of great importance to prove vocal cords mobility. Therefore, imaging during i-phonation is an elemental part of every thorough examination of the hypopharynx and larynx region. Multislice-spiral-CT allows almost isotropic imaging of the head and neck region and improves the assessment of tumor spread and lymph node metastases in arbitrary oblique planes. Thin structures (the base of the skull, the orbital floor, the hard palate) as well as the floor of the mouth can be evaluated sufficiently with multiplanar reformations. Usually, additional coronal scanning is not necessary with multislice-spiral-CT. Multislice-spiral-CT is especially advantageous in defining the critical relationships of tumor and lymph node metastases and for functional imaging of the hypopharynx and larynx not only in the

  11. Influence of ties on the behavior of short reinforced concrete columns strengthened by external CFRP

    Directory of Open Access Journals (Sweden)

    Sarsam Kaiss

    2018-01-01

    Full Text Available An experimental study was carried out to investigate the behavior of normal strength reinforce concret (RC circular short column strengthned with “carbon fiber reinforced polymer (CFRP sheets”. Three series comprising totally of (15 specimens loaded until failure under concentric compresion load. Strengthening was varied by changing the number of CFRP strips, spacing and wrapping methods. The findings of this research can be summarized as follows: for the columns without CFRP, the influence of the tie spacing was significant: compared with 130 mm tie spacing, dropping the spacing to 100 mm and 70 mm increased the load carrying capacity by 18% and 26%, respectively. The columns with less internal confinement (lesser amount of ties were strengthened more significantly by the CFRP than the ones with greater amount of internal ties. As an example of the varying effectiveness of the fully wrapped CFRP, the column with ties at 130 mm was strengthened by 90% with the CFRP. In contrast, the ones with 70 mm spaced ties only increased in strength with CFRP by 66%. Compared with the control specimen (no CFRP, the same amount of CFRP when used as hoop strips led to more strengthening than using CFRP as a spiral strip- the former led to nearly 9% more strengthening than the latter in the case of 130 mm spaced internal steel ties. In the case of 100 mm internal steel ties, the difference (between the hoops & spiral CFRP strengthening is close to 4%. In contrast, there is no difference between the two methods of strengthening in the heavily tied columns (70 mm tied spacing.

  12. Pathomorphism of spiral tibial fractures in computed tomography imaging.

    Science.gov (United States)

    Guzik, Grzegorz

    2011-01-01

    Spiral fractures of the tibia are virtually homogeneous with regard to their pathomorphism. The differences that are seen concern the level of fracture of the fibula, and, to a lesser extent, the level of fracture of the tibia, the length of fracture cleft, and limb shortening following the trauma. While conventional radiographs provide sufficient information about the pathomorphism of fractures, computed tomography can be useful in demonstrating the spatial arrangement of bone fragments and topography of soft tissues surrounding the fracture site. Multiple cross-sectional computed tomography views of spiral fractures of the tibia show the details of the alignment of bone chips at the fracture site, axis of the tibial fracture cleft, and topography of soft tissues that are not visible on standard radiographs. A model of a spiral tibial fracture reveals periosteal stretching with increasing spiral and longitudinal displacement. The cleft in tibial fractures has a spiral shape and its line is invariable. Every spiral fracture of both crural bones results in extensive damage to the periosteum and may damage bellies of the long flexor muscle of toes, flexor hallucis longus as well as the posterior tibial muscle. Computed tomography images of spiral fractures of the tibia show details of damage that are otherwise invisible on standard radiographs. Moreover, CT images provide useful information about the spatial location of the bone chips as well as possible threats to soft tissues that surround the fracture site. Every spiral fracture of the tibia is associated with disruption of the periosteum. 1. Computed tomography images of spiral fractures of the tibia show details of damage otherwise invisible on standard radiographs, 2. The sharp end of the distal tibial chip can damage the tibialis posterior muscle, long flexor muscles of the toes and the flexor hallucis longus, 3. Every spiral fracture of the tibia is associated with disruption of the periosteum.

  13. Chromatographic properties PLOT multicapillary columns.

    Science.gov (United States)

    Nikolaeva, O A; Patrushev, Y V; Sidelnikov, V N

    2017-03-10

    Multicapillary columns (MCCs) for gas chromatography make it possible to perform high-speed analysis of the mixtures of gaseous and volatile substances at a relatively large amount of the loaded sample. The study was performed using PLOT MCCs for gas-solid chromatography (GSC) with different stationary phases (SP) based on alumina, silica and poly-(1-trimethylsilyl-1-propyne) (PTMSP) polymer as well as porous polymers divinylbenzene-styrene (DVB-St), divinylbenzene-vinylimidazole (DVB-VIm) and divinylbenzene-ethylene glycol dimethacrylate (DVB-EGD). These MCCs have the efficiency of 4000-10000 theoretical plates per meter (TP/m) and at a column length of 25-30cm can separate within 10-20s multicomponent mixtures of substances belonging to different classes of chemical compounds. The sample amount not overloading the column is 0.03-1μg and depends on the features of a porous layer. Examples of separations on some of the studied columns are considered. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Spiral model pilot project information model

    Science.gov (United States)

    1991-01-01

    The objective was an evaluation of the Spiral Model (SM) development approach to allow NASA Marshall to develop an experience base of that software management methodology. A discussion is presented of the Information Model (IM) that was used as part of the SM methodology. A key concept of the SM is the establishment of an IM to be used by management to track the progress of a project. The IM is the set of metrics that is to be measured and reported throughout the life of the project. These metrics measure both the product and the process to ensure the quality of the final delivery item and to ensure the project met programmatic guidelines. The beauty of the SM, along with the IM, is the ability to measure not only the correctness of the specification and implementation of the requirements but to also obtain a measure of customer satisfaction.

  15. SPIRAL 2 RFQ Prototype First Tests

    CERN Document Server

    Ferdinand, Robin; Congretel, G; Curtoni, Aline; Delferriere, Olivier; Di Giacomo, Marco; France, Alain; Leboeuf, Didier; Thinel, Jean; Toussaint, Jean-Christian

    2005-01-01

    The SPIRAL2 RFQ is designed to accelerate at 88MHz two kinds of charge-over-mass ratio, Q/A, particles. The proposed injector can accelerate a 5 mA deuteron beam (Q/A=1/2) or a 1 mA particles beam with q/A=1/3 up to 0.75 MeV/A. It is a CW machine which has to show stable operation, provide the request availability, have the minimum losses in order to minimize the activation constraints and show the best quality/cost ratio. The prototype of this 4-vane RFQ has been built and tested. It allowed to verify the mechanical assembly concept (RFQ without any brazing step). The full power was easily injected in the cavity, with no concerns for the RF joints. The paper describes the different achievements.

  16. Fluid flow in a spiral microfluidic duct

    Science.gov (United States)

    Harding, Brendan; Stokes, Yvonne

    2018-04-01

    We consider the steady, pressure driven flow of a viscous fluid through a microfluidic device having the geometry of a planar spiral duct with a slowly varying curvature and height smaller than width. For this problem, it is convenient to express the Navier-Stokes equations in terms of a non-orthogonal coordinate system. Then, after applying appropriate scalings, the leading order equations admit a relatively simple solution in the central region of the duct cross section. First-order corrections with respect to the duct curvature and aspect ratio parameters are also obtained for this region. Additional correction terms are needed to ensure that no slip and no penetration conditions are satisfied on the side walls. Our solutions allow for a top wall shape that varies with respect to the radial coordinate which allows us to study the flow in a variety of cross-sectional shapes, including trapezoidal-shaped ducts that have been studied experimentally. At leading order, the flow is found to depend on the local height and slope of the top wall within the central region. The solutions are compared with numerical approximations of a classical Dean flow and are found to be in good agreement for a small duct aspect ratio and a slowly varying and small curvature. We conclude that the slowly varying curvature typical of spiral microfluidic devices has a negligible impact on the flow in the sense that locally the flow does not differ significantly from the classical Dean flow through a duct having the same curvature.

  17. Configuration Management Program Plan

    International Nuclear Information System (INIS)

    1991-01-01

    Westinghouse Savannah River Company (WSRC) has established a configuration management (CM) plan to execute the SRS CM Policy and the requirements of the DOE Order 4700.1. The Reactor Restart Division (RRD) has developed its CM Plan under the SRS CM Program and is implementing it via the RRD CM Program Plan and the Integrated Action Plan. The purpose of the RRD CM program is to improve those processes which are essential to the safe and efficient operation of SRS production reactors. This document provides details of this plan

  18. Magnetization reversal in ferromagnetic spirals via domain wall motion

    Science.gov (United States)

    Schumm, Ryan D.; Kunz, Andrew

    2016-11-01

    Domain wall dynamics have been investigated in a variety of ferromagnetic nanostructures for potential applications in logic, sensing, and recording. We present a combination of analytic and simulated results describing the reliable field driven motion of a domain wall through the arms of a ferromagnetic spiral nanowire. The spiral geometry is capable of taking advantage of the benefits of both straight and circular wires. Measurements of the in-plane components of the spirals' magnetization can be used to determine the angular location of the domain wall, impacting the magnetoresistive applications dependent on the domain wall location. The spirals' magnetization components are found to depend on the spiral parameters: the initial radius and spacing between spiral arms, along with the domain wall location. The magnetization is independent of the parameters of the rotating field used to move the domain wall, and therefore the model is valid for current induced domain wall motion as well. The speed of the domain wall is found to depend on the frequency of the rotating driving field, and the domain wall speeds can be reliably varied over several orders of magnitude. We further demonstrate a technique capable of injecting multiple domain walls and show the reliable and unidirectional motion of domain walls through the arms of the spiral.

  19. Galaxy Zoo: constraining the origin of spiral arms

    Science.gov (United States)

    Hart, Ross E.; Bamford, Steven P.; Keel, William C.; Kruk, Sandor J.; Masters, Karen L.; Simmons, Brooke D.; Smethurst, Rebecca J.

    2018-05-01

    Since the discovery that the majority of low-redshift galaxies exhibit some level of spiral structure, a number of theories have been proposed as to why these patterns exist. A popular explanation is a process known as swing amplification, yet there is no observational evidence to prove that such a mechanism is at play. By using a number of measured properties of galaxies, and scaling relations where there are no direct measurements, we model samples of SDSS and S4G spiral galaxies in terms of their relative halo, bulge and disc mass and size. Using these models, we test predictions of swing amplification theory with respect to directly measured spiral arm numbers from Galaxy Zoo 2. We find that neither a universal cored or cuspy inner dark matter profile can correctly predict observed numbers of arms in galaxies. However, by invoking a halo contraction/expansion model, a clear bimodality in the spiral galaxy population emerges. Approximately 40 per cent of unbarred spiral galaxies at z ≲ 0.1 and M* ≳ 1010M⊙ have spiral arms that can be modelled by swing amplification. This population display a significant correlation between predicted and observed spiral arm numbers, evidence that they are swing amplified modes. The remainder are dominated by two-arm systems for which the model predicts significantly higher arm numbers. These are likely driven by tidal interactions or other mechanisms.

  20. Propagation of spiral waves pinned to circular and rectangular obstacles.

    Science.gov (United States)

    Sutthiopad, Malee; Luengviriya, Jiraporn; Porjai, Porramain; Phantu, Metinee; Kanchanawarin, Jarin; Müller, Stefan C; Luengviriya, Chaiya

    2015-05-01

    We present an investigation of spiral waves pinned to circular and rectangular obstacles with different circumferences in both thin layers of the Belousov-Zhabotinsky reaction and numerical simulations with the Oregonator model. For circular objects, the area always increases with the circumference. In contrast, we varied the circumference of rectangles with equal areas by adjusting their width w and height h. For both obstacle forms, the propagating parameters (i.e., wavelength, wave period, and velocity of pinned spiral waves) increase with the circumference, regardless of the obstacle area. Despite these common features of the parameters, the forms of pinned spiral waves depend on the obstacle shapes. The structures of spiral waves pinned to circles as well as rectangles with the ratio w/h∼1 are similar to Archimedean spirals. When w/h increases, deformations of the spiral shapes are observed. For extremely thin rectangles with w/h≫1, these shapes can be constructed by employing semicircles with different radii which relate to the obstacle width and the core diameter of free spirals.

  1. Displacement and resonance behaviors of a piezoelectric diaphragm driven by a double-sided spiral electrode

    KAUST Repository

    Shen, Zhiyuan

    2012-04-03

    This paper presents the design of a lead zirconate titanate (PZT) diaphragm actuated by double-sided patterned electrodes. Au/Cr electrodes were deposited on bulk PZT wafers by sputtering while patterned by a lift-off process. SU-8 thick film was used to form the structural layer. Double-spiral electrode induced in-plane poling and piezoelectric elongation are converted to an out-of-plane displacement due to the confined boundary condition. The influence of different drive configurations and electrode parameters on deflection has been calculated by finite element methods (FEM) using a uniform field model. Impedance and quasi-static displacement spectra of the diaphragm were measured after poling. Adouble-sided patterned electrode diaphragm can be actuated by more drive configurations than a single-sided one. Compared with a single-sided electrode drive, a double-sided out-of-phase drive configuration increases the coupling coefficient of the fundamental resonance from 7.6% to 11.8%. The displacement response of the diaphragm increases from 2.6 to 8.6nmV 1. Configurations including the electric field component perpendicular to the poling direction can stimulate shear modes of the diaphragm. © 2012 IOP Publishing Ltd.

  2. The effect of pitch in multislice spiral/helical CT

    International Nuclear Information System (INIS)

    Wang, G.; Vannier, M.W.

    2000-01-01

    The purpose of this study is to understand the effect of pitch on raw data interpolation in multislice spiral/helical computed tomography (CT) and provide guidelines for scanner design and protocol optimization. Multislice spiral CT is mainly characterized by the three parameters: the number of detector arrays, the detector collimation, and the table increment per x-ray source rotation. The pitch in multislice spiral CT is defined as the ratio of the table increment over the detector collimation in this study. In parallel to the current framework for studying longitudinal image resolution, the central fan-beam rays of direct and opposite directions are considered, assuming a narrow cone-beam angle. Generally speaking, sampling in the Radon domain by the direct and opposite central rays is nonuniform along the longitudinal axis. Using a recently developed methodology for quantifying the sensibility of signal reconstruction from non-uniformly sampled finite points, the effect of pitch on raw data interpolation is analyzed in multislice spiral CT. Unlike single-slice spiral CT, in which image quality decreases monotonically as the pitch increases, the sensibility of raw data interpolation in multislice spiral CT increases, suggesting that image quality does not decrease monotonically in this case. The most favorable pitch can be found from the sensitivity-slice spiral CT is provided. The study on the effect of pitch using the sensitivity analysis approach reveals the fundamental characteristics of raw data interpolation in multislice spiral CT, and gives insights into interaction between pitch and image quality. These results may be valuable for design of multislice spiral CT scanners and imaging protocol optimization in clinical applications. (authors)

  3. Ames Optimized TCA Configuration

    Science.gov (United States)

    Cliff, Susan E.; Reuther, James J.; Hicks, Raymond M.

    1999-01-01

    Configuration design at Ames was carried out with the SYN87-SB (single block) Euler code using a 193 x 49 x 65 C-H grid. The Euler solver is coupled to the constrained (NPSOL) and the unconstrained (QNMDIF) optimization packages. Since the single block grid is able to model only wing-body configurations, the nacelle/diverter effects were included in the optimization process by SYN87's option to superimpose the nacelle/diverter interference pressures on the wing. These interference pressures were calculated using the AIRPLANE code. AIRPLANE is an Euler solver that uses a unstructured tetrahedral mesh and is capable of computations about arbitrary complete configurations. In addition, the buoyancy effects of the nacelle/diverters were also included in the design process by imposing the pressure field obtained during the design process onto the triangulated surfaces of the nacelle/diverter mesh generated by AIRPLANE. The interference pressures and nacelle buoyancy effects are added to the final forces after each flow field calculation. Full details of the (recently enhanced) ghost nacelle capability are given in a related talk. The pseudo nacelle corrections were greatly improved during this design cycle. During the Ref H and Cycle 1 design activities, the nacelles were only translated and pitched. In the cycle 2 design effort the nacelles can translate vertically, and pitch to accommodate the changes in the lower surface geometry. The diverter heights (between their leading and trailing edges) were modified during design as the shape of the lower wing changed, with the drag of the diverter changing accordingly. Both adjoint and finite difference gradients were used during optimization. The adjoint-based gradients were found to give good direction in the design space for configurations near the starting point, but as the design approached a minimum, the finite difference gradients were found to be more accurate. Use of finite difference gradients was limited by the

  4. Fabrication techniques of X-ray spiral zone plates

    International Nuclear Information System (INIS)

    Gao Nan; Zhu Xiaoli; Li Hailiang; Xie Changqing

    2010-01-01

    The techniques to make X-ray spiral zone plates using electron beam and X-ray lithography were studied. A master mask was fabricated on polyimide membrane by E-beam lithography and micro-electroplating. Spiral zone plates were efficiently replicated by X-ray lithography and micro-electroplating. By combining the techniques, spiral zone plates at 1 keV were successfully fabricate. With an outermost zone width of the 200 nm, and the gold absorbers thickness of 700 nm, the high quality zone plates can be used for X-ray phase contrast microscopy.(authors)

  5. Comments on H. Arp 'The persistent problem of spiral galaxies'

    International Nuclear Information System (INIS)

    Alfven, H.

    1987-04-01

    In his paper 'The persistent problem of Spiral Galaxies' H. Arp criticises the standard theory of spiral galaxies and demonstrates that introduction of plasma theory is necessary in order to understand the structure of spiral galaxies. In the present paper arguments are given in support of Arp's theory and suggestions are made how Arp's ideas should be developed. An important result of Arp's new approach is that there is no convincing argument for the belief that there is a 'missing mass'. This is important from a cosmological point of view. (author)

  6. A Software Development Simulation Model of a Spiral Process

    Science.gov (United States)

    Mizell, Carolyn; Malone, Linda

    2007-01-01

    There is a need for simulation models of software development processes other than the waterfall because processes such as spiral development are becoming more and more popular. The use of a spiral process can make the inherently difficult job of cost and schedule estimation even more challenging due to its evolutionary nature, but this allows for a more flexible process that can better meet customers' needs. This paper will present a discrete event simulation model of spiral development that can be used to analyze cost and schedule effects of using such a process in comparison to a waterfall process.

  7. Investigation on filter method for smoothing spiral phase plate

    Science.gov (United States)

    Zhang, Yuanhang; Wen, Shenglin; Luo, Zijian; Tang, Caixue; Yan, Hao; Yang, Chunlin; Liu, Mincai; Zhang, Qinghua; Wang, Jian

    2018-03-01

    Spiral phase plate (SPP) for generating vortex hollow beams has high efficiency in various applications. However, it is difficult to obtain an ideal spiral phase plate because of its continuous-varying helical phase and discontinued phase step. This paper describes the demonstration of continuous spiral phase plate using filter methods. The numerical simulations indicate that different filter method including spatial domain filter, frequency domain filter has unique impact on surface topography of SPP and optical vortex characteristics. The experimental results reveal that the spatial Gaussian filter method for smoothing SPP is suitable for Computer Controlled Optical Surfacing (CCOS) technique and obtains good optical properties.

  8. Thermal Analysis for Ion-Exchange Column System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Si Y.; King, William D.

    2012-12-20

    Models have been developed to simulate the thermal characteristics of crystalline silicotitanate ion exchange media fully loaded with radioactive cesium either in a column configuration or distributed within a waste storage tank. This work was conducted to support the design and operation of a waste treatment process focused on treating dissolved, high-sodium salt waste solutions for the removal of specific radionuclides. The ion exchange column will be installed inside a high level waste storage tank at the Savannah River Site. After cesium loading, the ion exchange media may be transferred to the waste tank floor for interim storage. Models were used to predict temperature profiles in these areas of the system where the cesium-loaded media is expected to lead to localized regions of elevated temperature due to radiolytic decay. Normal operating conditions and accident scenarios (including loss of solution flow, inadvertent drainage, and loss of active cooling) were evaluated for the ion exchange column using bounding conditions to establish the design safety basis. The modeling results demonstrate that the baseline design using one central and four outer cooling tubes provides a highly efficient cooling mechanism for reducing the maximum column temperature. In-tank modeling results revealed that an idealized hemispherical mound shape leads to the highest tank floor temperatures. In contrast, even large volumes of CST distributed in a flat layer with a cylindrical shape do not result in significant floor heating.

  9. Elimination of spiral chaos by periodic force for the Aliev-Panfilov model

    OpenAIRE

    Sakaguchi, Hidetsugu; Fujimoto, Takefumi

    2003-01-01

    Spiral chaos appears in the two dimensional Aliev-Panfilov model. The generation mechanism of the spiral chaos is related to the breathing instability of pulse trains. The spiral chaos can be eliminated by applying periodic force uniformly. The elimination of spiral chaos is most effective, when the frequency of the periodic force is close to that of the breathing motion.

  10. Toward a transport-based analysis of nutrient spiraling and uptake in streams

    Science.gov (United States)

    Runkel, Robert L.

    2007-01-01

    Nutrient addition experiments are designed to study the cycling of nutrients in stream ecosystems where hydrologic and nonhydrologic processes determine nutrient fate. Because of the importance of hydrologic processes in stream ecosystems, a conceptual model known as nutrient spiraling is frequently employed. A central part of the nutrient spiraling approach is the determination of uptake length (SW), the average distance traveled by dissolved nutrients in the water column before uptake. Although the nutrient spiraling concept has been an invaluable tool in stream ecology, the current practice of estimating uptake length from steady-state nutrient data using linear regression (called here the "SW approach") presents a number of limitations. These limitations are identified by comparing the exponential SW equation with analytical solutions of a stream solute transport model. This comparison indicates that (1) SW, is an aggregate measure of uptake that does not distinguish between main channel and storage zone processes, (2) SW, is an integrated measure of numerous hydrologie and nonhydrologic processes-this process integration may lead to difficulties in interpretation when comparing estimates of SW, and (3) estimates of uptake velocity and areal uptake rate (Vf and U) based on S W, are not independent of system hydrology. Given these findings, a transport-based approach to nutrient spiraling is presented for steady-state and time-series data sets. The transport-based approach for time-series data sets is suggested for future research on nutrient uptake as it provides a number of benefits, including the ability to (1) separately quantify main channel and storage zone uptake, (2) quantify specific hydrologic and nonhydrologic processes using various model parameters (process separation), (3) estimate uptake velocities and areal uptake rates that are independent of hydrologic effects, and (4) use short-term, non-plateau nutrient additions such that the effects of

  11. Gas/liquid flow configurations

    International Nuclear Information System (INIS)

    Bonin, Jacques; Fitremann, J.-M.

    1978-01-01

    Prediction of flow configurations (morphology) for gas/liquid or liquid/vapour mixtures is an important industrial problem which is not yet fully understood. The ''Flow Configurations'' Seminar of Societe Hydrotechnique de France has framed recommendations for investigation of potential industrial applications for flow configurations [fr

  12. Modeling of column apparatus processes

    CERN Document Server

    Boyadjiev, Christo; Boyadjiev, Boyan; Popova-Krumova, Petya

    2016-01-01

    This book presents a new approach for the modeling of chemical and interphase mass transfer processes in industrial column apparatuses, using convection-diffusion and average-concentration models. The convection-diffusion type models are used for a qualitative analysis of the processes and to assess the main, small and slight physical effects, and then reject the slight effects. As a result, the process mechanism can be identified. It also introduces average concentration models for quantitative analysis, which use the average values of the velocity and concentration over the cross-sectional area of the column. The new models are used to analyze different processes (simple and complex chemical reactions, absorption, adsorption and catalytic reactions), and make it possible to model the processes of gas purification with sulfur dioxide, which form the basis of several patents.

  13. Software Configurable Multichannel Transceiver

    Science.gov (United States)

    Freudinger, Lawrence C.; Cornelius, Harold; Hickling, Ron; Brooks, Walter

    2009-01-01

    Emerging test instrumentation and test scenarios increasingly require network communication to manage complexity. Adapting wireless communication infrastructure to accommodate challenging testing needs can benefit from reconfigurable radio technology. A fundamental requirement for a software-definable radio system is independence from carrier frequencies, one of the radio components that to date has seen only limited progress toward programmability. This paper overviews an ongoing project to validate the viability of a promising chipset that performs conversion of radio frequency (RF) signals directly into digital data for the wireless receiver and, for the transmitter, converts digital data into RF signals. The Software Configurable Multichannel Transceiver (SCMT) enables four transmitters and four receivers in a single unit the size of a commodity disk drive, programmable for any frequency band between 1 MHz and 6 GHz.

  14. Configuring the autism epidemic

    DEFF Research Database (Denmark)

    Seeberg, Jens; Christensen, Fie Lund Lindegaard

    2017-01-01

    Autism has been described as an epidemic, but this claim is contested and may point to an awareness epidemic, i.e. changes in the definition of what autism is and more attention being invested in diagnosis leading to a rise in registered cases. The sex ratio of children diagnosed with autism...... is skewed in favour of boys, and girls with autism tend to be diagnosed much later than boys. Building and further developing the notion of ‘configuration’ of epidemics, this article explores the configuration of autism in Denmark, with a particular focus on the health system and social support to families...... with children diagnosed with autism, seen from a parental perspective. The article points to diagnostic dynamics that contribute to explaining why girls with autism are not diagnosed as easily as boys. We unfold these dynamics through the analysis of a case of a Danish family with autism....

  15. Deployable reflector configurations

    Science.gov (United States)

    Meinel, A. B.; Meinel, M. P.; Woolf, N. J.

    Both the theoretical reasons for considering a non-circular format for the Large Deployable Reflector, and a potentially realizable concept for such a device, are discussed. The optimum systems for diffraction limited telescopes with incoherent detection have either a single filled aperture, or two such apertures as an interferometer to synthesize a larger aperture. For a single aperture of limited area, a reflector in the form of a slot can be used to give increased angular resolution. It is shown how a 20 x 8 meter telescope can be configured to fit the Space Shuttle bay, and deployed with relatively simple operations. The relationship between the sunshield design and the inclination of the orbit is discussed. The possible use of the LDR as a basic module to permit the construction of supergiant space telescopes and interferometers both for IR/submm studies and for the entire ultraviolet through mm wave spectral region is discussed.

  16. Studies of column supported towers

    International Nuclear Information System (INIS)

    Chauvel, D.; Costaz, J.-L.

    1991-01-01

    As a result of a research and development programme into the civil engineering of cooling towers launched in 1978 by Electricite de France, very high cooling towers were built at Golfech and Chooz, in France, using column supports. This paper discusses the evolution of this new type of support from classical diagonal supports, presents some of the results of design calculations and survey measurements taken during construction of the shell and analyses the behaviour of the structure. (author)

  17. SPEEDUPtrademark ion exchange column model

    International Nuclear Information System (INIS)

    Hang, T.

    2000-01-01

    A transient model to describe the process of loading a solute onto the granular fixed bed in an ion exchange (IX) column has been developed using the SpeedUptrademark software package. SpeedUp offers the advantage of smooth integration into other existing SpeedUp flowsheet models. The mathematical algorithm of a porous particle diffusion model was adopted to account for convection, axial dispersion, film mass transfer, and pore diffusion. The method of orthogonal collocation on finite elements was employed to solve the governing transport equations. The model allows the use of a non-linear Langmuir isotherm based on an effective binary ionic exchange process. The SpeedUp column model was tested by comparing to the analytical solutions of three transport problems from the ion exchange literature. In addition, a sample calculation of a train of three crystalline silicotitanate (CST) IX columns in series was made using both the SpeedUp model and Purdue University's VERSE-LC code. All test cases showed excellent agreement between the SpeedUp model results and the test data. The model can be readily used for SuperLigtrademark ion exchange resins, once the experimental data are complete

  18. Software trends for both the GANIL and spiral control

    International Nuclear Information System (INIS)

    David, L.; Lecorche, E.

    1999-01-01

    The Ganil facility has been running with a new control system since 1993. Many improvements have been done since that time to bring new capabilities to the system. So, in February 1996, when the Spiral control system was designed, it was mainly considered as an extension of the Ganil control system. This paper briefly recalls the basic architecture of the whole control system and the main choices upon which it relies. Then it presents the new software trends, to show how the Spiral control system has been integrated alongside the existing one. The last part describe the new developments and the most significant functionalities it brings as seen from the operator point of view, with some emphasis about the application programs for beam tuning. Indeed, these new programs have to be provided both for the spiral tuning with exotic ions beams and for the coupling of the Spiral and older Ganil facilities. (authors)

  19. Density wave theory and the classification of spiral galaxies

    International Nuclear Information System (INIS)

    Roberts, W.W. Jr.; Roberts, M.S.; Shu, F.H.

    1975-01-01

    Axisymmetric models of disk galaxies taken together with the density wave theory allow us to distinguish and categorize spiral galaxies by means of two fundamental galactic parameters: the total mass of the galaxy, divided by a characteristic dimension; and the degree of concentration of mass toward the galactic center. These two parameters govern the strength of the galactic shocks in the interstellar gas and the geometry of the spiral wave pattern. In turn, the shock strength and the theoretical pitch angle of the spiral arms play a major role in determining the degree of development of spiral structure in a galaxy and its Hubble type. The application of these results to 24 external galaxies demonstrates that the categorization of galaxies according to this theoretical framework correlates well with the accepted classification of these galaxies within the observed sequences of luminosity class and Hubble type

  20. The Clinical Learning Spiral: A Model to Develop Reflective Practitioners.

    Science.gov (United States)

    Stockhausen, Lynette

    1994-01-01

    The Clinical Learning Spiral incorporates reflective processes into undergraduate nursing education. It entails successive cycles of four phases: preparative (briefing, planning), constructive (practice development), reflective (debriefing), and reconstructive (planning for change and commitment to action). (SK)

  1. A model of the formation of spiral galaxies

    International Nuclear Information System (INIS)

    Brown, W.K.; Gritzo, L.A.

    1980-01-01

    It has been verified that the analytical results in a previous article for elliptical galaxies may also be used to describe spiral galaxies. Exploration of the model for small values of the principal parameter THETA yields surface mass density distributions as functions of radius which, while always displaying the exponential disk, describe both of the subcategories of spiral galaxies. Within the constraints of the model, the two main questions concerning spirals posed some years ago by Freeman appear to be successfully addressed. An intrinsic model mechanism has been identified that could account for the extended state of elliptical galaxies, as opposed to the flat disks of spirals. In general, the model correctly describes the relative sizes of the various types of galaxies. (orig.)

  2. Origin choice and petal loss in the flower garden of spiral wave tip trajectories

    OpenAIRE

    Gray, Richard A.; Wikswo, John P.; Otani, Niels F.

    2009-01-01

    Rotating spiral waves have been observed in numerous biological and physical systems. These spiral waves can be stationary, meander, or even degenerate into multiple unstable rotating waves. The spatiotemporal behavior of spiral waves has been extensively quantified by tracking spiral wave tip trajectories. However, the precise methodology of identifying the spiral wave tip and its influence on the specific patterns of behavior remains a largely unexplored topic of research. Here we use a two...

  3. Two generalizations of column-convex polygons

    International Nuclear Information System (INIS)

    Feretic, Svjetlan; Guttmann, Anthony J

    2009-01-01

    Column-convex polygons were first counted by area several decades ago, and the result was found to be a simple, rational, generating function. In this work we generalize that result. Let a p-column polyomino be a polyomino whose columns can have 1, 2, ..., p connected components. Then column-convex polygons are equivalent to 1-convex polyominoes. The area generating function of even the simplest generalization, namely 2-column polyominoes, is unlikely to be solvable. We therefore define two classes of polyominoes which interpolate between column-convex polygons and 2-column polyominoes. We derive the area generating functions of those two classes, using extensions of existing algorithms. The growth constants of both classes are greater than the growth constant of column-convex polyominoes. Rather tight lower bounds on the growth constants complement a comprehensive asymptotic analysis.

  4. Scintigraphic diagnosis of spiral fracture in young children

    International Nuclear Information System (INIS)

    Hossein-Foucher, C.; Venel, H.; Lecouffe, P.; Ythier, H.; Legghe, R.; Marchandise, X.

    1988-01-01

    8 cases of unsuspected bone fracture in children, identified at bone scan are reported. Common features were the children's young age (1 to 3 years), the absence of clinical suspicion, the initially normal X-rays, the fracture type (spiral fracture of the tibia undisplaced), and the uniform appearance of the bone scan. These data confim the value of bone scan in limping children and suggest that spiral fracture of the tibia is a frequent and underdiagnosed condition in children [fr

  5. Observational effects of explosions in the nuclei of spiral galaxies

    International Nuclear Information System (INIS)

    Sanders, R.H.; Bania, T.M.

    1976-01-01

    We conclude that an explosive event will produce a distinct observational signature evidenced by an inner ringlike structure of the principal spiral tracers, conspicuous dips in the gas rotation curve at the locus of this ring, and a ringlike or double radio structure in the plane of the galaxy. Evidence is presented supporting the suggestion that one particular spiral galaxy, NGC 4736, exhibits this characteristic signature and therefore is a galaxy which may have undergone a recent explosive event in its nucleus

  6. Digitized Spiral Drawing: A Possible Biomarker for Early Parkinson's Disease.

    Science.gov (United States)

    San Luciano, Marta; Wang, Cuiling; Ortega, Roberto A; Yu, Qiping; Boschung, Sarah; Soto-Valencia, Jeannie; Bressman, Susan B; Lipton, Richard B; Pullman, Seth; Saunders-Pullman, Rachel

    2016-01-01

    Pre-clinical markers of Parkinson's Disease (PD) are needed, and to be relevant in pre-clinical disease, they should be quantifiably abnormal in early disease as well. Handwriting is impaired early in PD and can be evaluated using computerized analysis of drawn spirals, capturing kinematic, dynamic, and spatial abnormalities and calculating indices that quantify motor performance and disability. Digitized spiral drawing correlates with motor scores and may be more sensitive in detecting early changes than subjective ratings. However, whether changes in spiral drawing are abnormal compared with controls and whether changes are detected in early PD are unknown. 138 PD subjects (50 with early PD) and 150 controls drew spirals on a digitizing tablet, generating x, y, z (pressure) data-coordinates and time. Derived indices corresponded to overall spiral execution (severity), shape and kinematic irregularity (second order smoothness, first order zero-crossing), tightness, mean speed and variability of spiral width. Linear mixed effect adjusted models comparing these indices and cross-validation were performed. Receiver operating characteristic analysis was applied to examine discriminative validity of combined indices. All indices were significantly different between PD cases and controls, except for zero-crossing. A model using all indices had high discriminative validity (sensitivity = 0.86, specificity = 0.81). Discriminative validity was maintained in patients with early PD. Spiral analysis accurately discriminates subjects with PD and early PD from controls supporting a role as a promising quantitative biomarker. Further assessment is needed to determine whether spiral changes are PD specific compared with other disorders and if present in pre-clinical PD.

  7. A Software Development Simulation Model of a Spiral Process

    OpenAIRE

    Carolyn Mizell; Linda Malone

    2009-01-01

    This paper will present a discrete event simulation model of a spiral development lifecycle that can be used to analyze cost and schedule effects of using such a process in comparison to a waterfall process. There is a need for simulation models of software development processes other than the waterfall due to new processes becoming more widely used in order to overcome the limitations of the traditional waterfall lifecycle. The use of a spiral process can make the inherently difficult job of...

  8. The accelerated ISOL technique and the SPIRAL project

    International Nuclear Information System (INIS)

    Villari, A.C.C.

    2001-01-01

    The accelerated ISOL technique is presented as an introduction to the present status of the SPIRAL facility. SPIRAL is based on the very high intensity light and heavy ion beams available at GANIL. The facility will deliver radioactive beams with energies in the range between 1.7 A and 25 A MeV. The presently target-ion source production system, as well the new developments undertaken by the target ion-source group at GANIL are presented. (authors)

  9. Lung studies with spiral CT. pitch 1 versus pitch 2

    International Nuclear Information System (INIS)

    Sartoni Galloni, S.; Miceli, M.; Lipparino, M.; Burzi, M.; Gigli, F.; Rossi, M.S.; Santoli, G.; Guidarelli, G.

    1999-01-01

    In Spiral CT, the pitch is the ratio of the distance to tabletop travels per 360 degrees rotation to nominal slice width, expressed in mm. Performing Spiral CT examination with pitch 2 allows to reduce examination time, exposure and contrast dose, and X-ray tube overload. The authors investigated the yield of pitch 2 in lung parenchyma studies, particular relative to diagnostic image quality [it

  10. Synchronizing spiral waves in a coupled Rössler system

    International Nuclear Information System (INIS)

    Gao Jia-Zhen; Yang Shu-Xin; Xie Ling-Ling; Gao Ji-Hua

    2011-01-01

    The synchronisation of spiral patterns in a drive-response Rössler system is studied. The existence of three types of synchronisation is revealed by inspecting the coupling parameter space. Two transient stages of phase synchronisation and partial synchronisation are observed in a comparatively weak feedback coupling parameter regime, whilst complete synchronisation of spirals is found with strong negative couplings. Detailed observations of the synchronous process, such as oscillatory frequencies, parameters mismatches and amplitude variations, etc, are investigated via numerical simulations. (general)

  11. Application of Configurators in Networks

    DEFF Research Database (Denmark)

    Malis, Martin; Hvam, Lars

    2003-01-01

    Shorter lead-time, improved quality of product specifications and better communication with customers and suppliers are benefits derived from the application of configurators. Configurators are knowledge-based IT-systems that can be applied to deal with product knowledge and to support different...... processes in a company. Traditionally, configurators have been used as an internal tool. In this paper focus will be on the application of configurators in a network of companies, and a procedure for developing product configurators in a network of companies will be presented. The aim is to present...... a structured guideline, tools and methods on how to successfully develop configurators in a network perspective. Findings presented in this paper are supported by research in a case company. The results from the empirical work show a huge potential for the application of configurators in networks of companies....

  12. CHARACTERISTICS OF SPIRAL ARMS IN LATE-TYPE GALAXIES

    International Nuclear Information System (INIS)

    Honig, Z. N.; Reid, M. J.

    2015-01-01

    We have measured the positions of large numbers of H II regions in four nearly face-on, late-type, spiral galaxies: NGC 628 (M74), NGC 1232, NGC 3184, and NGC 5194 (M51). Fitting log-periodic spiral models to segments of each arm yields local estimates of spiral pitch angle and arm width. While pitch angles vary considerably along individual arms, among arms within a galaxy, and among galaxies, we find no systematic trend with galactocentric distance. We estimate the widths of the arm segments from the scatter in the distances of the H II regions from the spiral model. All major arms in these galaxies show spiral arm width increasing with distance from the galactic center, similar to the trend seen in the Milky Way. However, in the outermost parts of the galaxies, where massive star formation declines, some arms reverse this trend and narrow. We find that spiral arms often appear to be composed of segments of ∼5 kpc length, which join to form kinks and abrupt changes in pitch angle and arm width; these characteristics are consistent with properties seen in the large N-body simulations of D'Onghia et al. and others

  13. An experimental study on the influence of new spiral stent(Hanaro) on the vascular structures

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hyung; Chung, Jin Wook; Jeong, Yoong Ki; Kook, Myeong Cherl; Seo, Jung Wook [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of); Lim, Myung Kwan [Inha Univ. College of Medicine, Incheon (Korea, Republic of)

    1996-06-01

    The purpose of this study was to evaluate basic experimental data for the clinical application of a self-expandable stainless steel intravascular Hanaro spiral stent. For evaluation of the physical properties of the Hanaro stent, hoop strength, radioopacity, longitudinal flexibility, and foreshortening were measured. Twelve intravascular hanaro spiral stents were placed in the infrarenal abdominal aorta (n=6) and common iliac artery (n=6) in six mongrel dogs. Angiography and light microscopic examination were performed after one, two and eight months of placement of the stents. The stent had good radioopacity and was deployed with minimal foreshortening. hoop strength of a 6 mm-interval bend was found to be superior to that of 8 mm- and 10 mm-bend stent. On angiography the patency rate and thrombosis rate were 100% and 0% in the abdominal aorta and 50% in the common iliac artery, respectively. Minimal corrosion was seen in all stents, and they appeared to be biocompatible. The stent wires were covered with well-developed neointima which after one month had mostly fibroblast and collagen tissue ; the thickness of the neointima increased gradually during a period of eight months. At the end of that period, collagen fibres in the neointima were denser and showed a more paralled configuration than at one month. The Hanaro stent has good physical properties and also has a high patency rate, and good biocompatibilities. The stent may therefore be reliably and safely deployed in the human vascular system.

  14. High-Tc Superconducting Thick-Film Spiral Magnet: Development and Characterization of a Single Spiral Module

    National Research Council Canada - National Science Library

    McGinnis, W

    1997-01-01

    The objective of this project was to make characterized and numerically model prototype modules of a new type of superconducting electromagnet based on stacked spirals of superconducting thick films...

  15. 29 CFR 1926.755 - Column anchorage.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Column anchorage. 1926.755 Section 1926.755 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Steel Erection § 1926.755 Column anchorage. (a) General requirements for erection stability. (1) All columns shall be anchored by a minimum of 4 anchor...

  16. Adsorption columns for use in radioimmunoassays

    International Nuclear Information System (INIS)

    1976-01-01

    Adsorption columns are provided which can be utilized in radioimmunoassay systems such as those involving the separation of antibody-antigen complexes from free antigens. The preparation of the columns includes the treatment of retaining substrate material to render it hydrophilic, preparation and degassing of the separation material and loading the column

  17. Thermal process of an air column

    International Nuclear Information System (INIS)

    Lee, F.T.

    1994-01-01

    Thermal process of a hot air column is discussed based on laws of thermodynamics. The kinetic motion of the air mass in the column can be used as a power generator. Alternatively, the column can also function as a exhaust/cooler

  18. A neutron beam facility at Spiral-2

    Energy Technology Data Exchange (ETDEWEB)

    Ledoux, X.; Bauge, E.; Belier, G.; Ethvignot, T.; Taieb, J.; Varignon, C. [CEA Bruyeres-le-Chatel, DIF, 91 (France); Andriamonje, S.; Dore, D.; Dupont, E.; Gunsing, F.; Ridikas, D.; Takibayev, A. [CEA Saclay, DSM/IRFU/SPhN, 91 - Gif-sur-Yvette (France); Blideanu, V. [CEA Saclay, DSM/IRFU/Senac, 91 - Gif-sur-Yvette (France); Aiche, M.; Barreau, G.; Czajkowski, S.; Jurado, B. [Centre d' Etudes Nucleaires de Bordeaux Gradignan, 33 (France); Ban, G.; Lecolley, F.R.; Lecolley, J.F.; Lecouey, J.L.; Marie, N.; Steckmeyer, J.C. [LPC, 14 - Caen (France); Dessagne, P.; Kerveno, M.; Rudolf, G. [IPHC, 57 - Strasbourg (France); Bem, P.; Mrazek, J.; Novak, J. [NPI, Rez (Czech Republic); Blomgren, J.; Pomp, S. [Uppsala Univ., Dept. of Physics and Astronomy (Sweden); Fischer, U.; Herber, S.; Simakov, S.P. [FZK, Karlsruhe (Germany); Jacquot, B.; Rejmund, F. [GANIL, 14 - Caen (France); Avrigeanu, M.; Avrigeanu, V.; Borcea, C.; Negoita, F.; Petrascu, M. [NIPNE, Bucharest (Romania); Oberstedt, S.; Plompen, A.J.M. [JRC/IRMM, Geel (Belgium); Shcherbakov, O. [PNPI, Gatchina (Russian Federation); Fallot, M. [Subatech, 44 - Nantes (France); Smith, A.G.; Tsekhanovich, I. [Manchester Univ., Dept. of Physics and Astronomy (United Kingdom); Serot, O.; Sublet, J.C. [CEA Cadarache, DEN, 13 - Saint-Paul-lez-Durance (France); Perrot, L.; Tassan-Got, L. [IPNO, 91 - Orsay (France); Caillaud, T.; Giot, L.; Landoas, O.; Ramillon, J.M.; Rosse, B.; Thfoin, I. [CIMAP, 14 - Caen (France); Balanzat, E.; Bouffard, S.; Guillous, S.; Oberstedt, A. [Orebro Univ. (Sweden)

    2009-07-01

    The future Spiral-2 facility, dedicated to the production of intense radioactive ion beams, is based on a high-power superconducting driver Linac, delivering high-intensity deuteron, proton and heavy ion beams. These beams are particularly well suited to the production of neutrons in the 100 keV- 40 MeV energy range, a facility called 'Neutrons for Science' (NFS) will be built in the LINAG Experimental Area (LEA). NFS, operational in 2012, will be composed of a pulsed neutron beam for in-flight measurements and irradiation stations for activation measurements and material studies. Thick C and Be converters and a deuteron beam will produce an intense continuous neutron spectrum, while a thin {sup 7}Li target and a proton beam allow to generate quasi-mono-energetic neutrons. In the present work we show how the primary ion beam characteristics (energy, time resolution and intensity) are adequate to create a neutron time-of-flight facility delivering intense neutron fluxes in the 100 keV-40 MeV energy range. Irradiation stations for neutron, proton and deuteron reactions will also allow to perform cross-section measurements by means of the activation technique. Light-ion beams will be used to study radiation damage effects on materials for the nuclear industry. (authors)

  19. Galactic spiral arms formed by central explosions

    International Nuclear Information System (INIS)

    Havnes, O.

    1978-01-01

    Calculations have been made of spiral arm formation due to central explosions in a nucleus surrounded by a disc containing most of the galactic mass with the purpose of obtaining estimates on lifetimes of arms and the requirements on the energy involved in the process. The ejected gas is taken to be a few percent, or less, of the central nucleus and is ejected with velocities of the order of 1000 km s -1 . The gas, considered to be in forms of blobs, moves under the gravitational force from the disc and the nucleus and the drag force by the gas in the disc. The orbits of the blobs evolve towards the circular orbits of the disc due to this drag force and the velocities in the arms will therefore, after some time, approach those of a normal rotation curve. A relatively open structure will last 8 years. Stable ring structures with longer lifetimes may be formed by some explosions. With an energy of approximately 5 x 10 57 erg in the initial gas-blob motion and a duration of the explosion of approximately 10 7 years, the energy output in such explosions has to be > 10 43 erg s -1 . (Auth.)

  20. Flocculent and grand design spiral galaxies in groups: time scales for the persistence of grand design spiral structures

    International Nuclear Information System (INIS)

    Elmegreen, B.G.; Elmegreen, D.M.

    1983-01-01

    Spiral arm classifications were made for 261 low-inclination galaxies in groups listed by Huchra and Geller. The fractional occurrence of grand design spiral structure in nonbarred galaxies was found to increase from approx.0.1 to approx.0.6 and then level off as the group crossing rate or galaxy collision rate in a group increases. A simple model is discussed where the random encounters between galaxies of any type and flocculent galaxies induce transient grand design spirals in the flocculent galaxies. If this grand-design stimulation occurs for binary collisions with impact parameters less than αR 25 , were R 25 is the galactic radius at 25 mag arcsec - 2 , and if the induced grand design spirals persist for an average time equal to #betta# galactic rotations, then the quantity α 2 #betta# equals approximately 3 x 10 4 . If binary collisions are responsible for grand design spirals, then this result implies either that the induced spirals last for many galactic rotations (#betta#>15), or that they can be stimulated by very remote encounters (α>45.) Alternatively, grand design spirals may be stimulated by multiple galaxy encounters, which would be the case for such large α, or by interactions with the potential well of the associated group, rather than by simple binary encounters. Weak correlations between the grand design fraction and the galaxy size, or between this fraction and the total number of galaxies in a group, were also found. Spiral structures of barred galaxies show no correlations with group environment

  1. SPIRAL COUNTER-CURRENT CHROMATOGRAPHY OF SMALL MOLECULES, PEPTIDES AND PROTEINS USING THE SPIRAL TUBING SUPPORT ROTOR

    OpenAIRE

    Knight, Martha; Finn, Thomas M.; Zehmer, John; Clayton, Adam; Pilon, Aprile

    2011-01-01

    An important advance in countercurrent chromatography (CCC) carried out in open flow-tubing coils, rotated in planetary centrifuges, is the new design to spread out the tubing in spirals. More spacing between the tubing was found to significantly increase the stationary phase retention, such that now all types of two-phase solvent systems can be used for liquid-liquid partition chromatography in the J-type planetary centrifuges. A spiral tubing support (STS) frame with circular channels was c...

  2. Configurational isomerism in polyoxovanadates

    Energy Technology Data Exchange (ETDEWEB)

    Mahnke, Lisa K.; Naether, Christian; Bensch, Wolfgang [Institut fuer Anorganische Chemie, Christian-Albrechts-Universitaet, Kiel (Germany); Kondinski, Aleksandar; Van Leusen, Jan; Monakhov, Kirill Yu.; Koegerler, Paul [Institut fuer Anorganische Chemie, RWTH Aachen University (Germany); Warzok, Ulrike; Schalley, Christoph A. [Institut fuer Chemie und Biochemie, Freie Universitaet Berlin (Germany)

    2018-03-05

    A water-soluble derivative of the polyoxovanadate {V_1_5E_6O_4_2} (E=semimetal) archetype enables the study of cluster shell rearrangements driven by supramolecular interactions. A reaction unique to E=Sb, induced exclusively by ligand metathesis in peripheral [Ni(ethylenediamine){sub 3}]{sup 2+} counterions, results in the formation of the metastable α{sub 1}* configurational isomer of the {V_1_4Sb_8O_4_2} cluster type. Contrary to all other polyoxovanadate shell architectures, this isomer comprises an inward-oriented vanadyl group and is ca. 50 and 12 kJ mol{sup -1} higher in energy than the previously isolated α and β isomers, respectively. We discuss this unexpected reaction in light of supramolecular Sb-O..V and Sb-O..Sb contacts manifested in {V_1_4Sb_8O_4_2}{sub 2} dimers detected in the solid state. ESI MS experiments confirm the stability of these dimers also in solution and in the gas phase. DFT calculations indicate that other, as of yet elusive isomers of {V_1_4Sb_8}, might be accessible as well. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Configuration space Faddeev calculations

    International Nuclear Information System (INIS)

    Payne, G.L.; Klink, W.H.; Ployzou, W.N.

    1991-01-01

    The detailed study of few-body systems provides one of the most precise tools for studying the dynamics of nuclei. Our research program consists of a careful theoretical study of the nuclear few-body systems. During the past year we have completed several aspects of this program. We have continued our program of using the trinucleon system to investigate the validity of various realistic nucleon-nucleon potentials. Also, the effects of meson-exchange currents in nuclear systems have been studied. Initial calculations using the configuration-space Faddeev equations for nucleon-deuteron scattering have been completed. With modifications to treat relativistic systems, few-body methods can be applied to phenomena that are sensitive to the structure of the individual hadrons. We have completed a review of Relativistic Hamiltonian Dynamics in Nuclear and Particle Physics for Advances in Nuclear Physics. Although it is called a review, it is a large document that contains a significant amount of new research

  4. Simulator configuration management system

    International Nuclear Information System (INIS)

    Faulent, J.; Brooks, J.G.

    1990-01-01

    The proposed revisions to ANS 3.5-1985 (Section 5) require Utilities to establish a simulator Configuration Management System (CMS). The proposed CMS must be capable of: Establishing and maintaining a simulator design database. Identifying and documenting differences between the simulator and its reference plant. Tracking the resolution of identified differences. Recording data to support simulator certification, testing and maintenance. This paper discusses a CMS capable of meeting the proposed requirements contained in ANS 3.5. The system will utilize a personal computer and a relational database management software to construct a simulator design database. The database will contain records to all reference nuclear plant data used in designing the simulator, as well as records identifying all the software, hardware and documentation making up the simulator. Using the relational powers of the database management software, reports will be generated identifying the impact of reference plant changes on the operation of the simulator. These reports can then be evaluated in terms of training needs to determine if changes are required for the simulator. If a change is authorized, the CMS will track the change through to its resolution and then incorporate the change into the simulator design database

  5. Research on performance of upstream pumping mechanical seal with different deep spiral groove

    International Nuclear Information System (INIS)

    Wang, Q; Chen, H L; Liu, T; Liu, Y H; Liu, Z B; Liu, D H

    2012-01-01

    As one new type of mechanical seal, Upstream Pumping Mechanical Seal has been widely used in fluid machinery. In this paper, structure of spiral groove is innovatively optimized to improve performance of Upstream Pumping Mechanical Seal with Spiral Groove: keeping the dam zone and the weir zone not changed, changing the bottom shape of spiral groove only, substituting different deep spiral groove for equal deep spiral groove. The simulation on Upstream Pumping Mechanical Seal with different deep spiral grooves is done using FVM method. According to calculation, the performances of opening force and pressure distribution on seals face are obtained. Five types of spiral grooves are analyzed, namely equal deep spiral groove, circumferential convergent ladder-like different deep spiral groove, circumferential divergent ladder-like different deep spiral groove, radial convergent ladder-like different deep spiral groove and radial divergent ladder-like different deep spiral groove. This paper works on twenty-five working conditions. The results indicate the performances of circumferential divergent 2-ladder different deep spiral groove are better than the others, with more opening force and better stabilization, while with the same leakage. The outcome provides theoretical support for application of Upstream Pumping Mechanical Seal with circumferential convergent ladder-like different deep spiral groove.

  6. Research on performance of upstream pumping mechanical seal with different deep spiral groove

    Science.gov (United States)

    Wang, Q.; Chen, H. L.; Liu, T.; Liu, Y. H.; Liu, Z. B.; Liu, D. H.

    2012-11-01

    As one new type of mechanical seal, Upstream Pumping Mechanical Seal has been widely used in fluid machinery. In this paper, structure of spiral groove is innovatively optimized to improve performance of Upstream Pumping Mechanical Seal with Spiral Groove: keeping the dam zone and the weir zone not changed, changing the bottom shape of spiral groove only, substituting different deep spiral groove for equal deep spiral groove. The simulation on Upstream Pumping Mechanical Seal with different deep spiral grooves is done using FVM method. According to calculation, the performances of opening force and pressure distribution on seals face are obtained. Five types of spiral grooves are analyzed, namely equal deep spiral groove, circumferential convergent ladder-like different deep spiral groove, circumferential divergent ladder-like different deep spiral groove, radial convergent ladder-like different deep spiral groove and radial divergent ladder-like different deep spiral groove. This paper works on twenty-five working conditions. The results indicate the performances of circumferential divergent 2-ladder different deep spiral groove are better than the others, with more opening force and better stabilization, while with the same leakage. The outcome provides theoretical support for application of Upstream Pumping Mechanical Seal with circumferential convergent ladder-like different deep spiral groove.

  7. Multiple spiral patterns in the transitional disk of HD 100546

    Science.gov (United States)

    Boccaletti, A.; Pantin, E.; Lagrange, A.-M.; Augereau, J.-C.; Meheut, H.; Quanz, S. P.

    2013-12-01

    Context. Protoplanetary disks around young stars harbor many structures related to planetary formation. Of particular interest, spiral patterns were discovered among several of these disks and are expected to be the sign of gravitational instabilities leading to giant planet formation or gravitational perturbations caused by already existing planets. In this context, the star HD 100546 presents some specific characteristics with a complex gaseous and dusty disk that includes spirals, as well as a possible planet in formation. Aims: The objective of this study is to analyze high-contrast and high angular resolution images of this emblematic system to shed light on critical steps in planet formation. Methods: We retrieved archival images obtained at Gemini in the near IR (Ks band) with the instrument NICI and processed the data using an advanced high contrast imaging technique that takes advantage of the angular differential imaging. Results: These new images reveal the spiral pattern previously identified with Hubble Space Telescope (HST) with an unprecedented resolution, while the large-scale structure of the disk is mostly cancelled by the data processing. The single pattern to the southeast in HST images is now resolved into a multi-armed spiral pattern. Using two models of a gravitational perturber orbiting in a gaseous disk, we attempted to constrain the characteristics of this perturber, assuming that each spiral is independent, and drew qualitative conclusions. The non-detection of the northeast spiral pattern observed in HST allows putting a lower limit on the intensity ratio between the two sides of the disk, which if interpreted as forward scattering, yields a larger anisotropic scattering than is derived in the visible. Also, we find that the spirals are likely to be spatially resolved with a thickness of about 5-10 AU. Finally, we did not detect the candidate planet in formation recently discovered in the Lp band, with a mass upper limit of 16-18 MJ

  8. Single-shot spiral imaging at 7 T.

    Science.gov (United States)

    Engel, Maria; Kasper, Lars; Barmet, Christoph; Schmid, Thomas; Vionnet, Laetitia; Wilm, Bertram; Pruessmann, Klaas P

    2018-03-25

    The purpose of this work is to explore the feasibility and performance of single-shot spiral MRI at 7 T, using an expanded signal model for reconstruction. Gradient-echo brain imaging is performed on a 7 T system using high-resolution single-shot spiral readouts and half-shot spirals that perform dual-image acquisition after a single excitation. Image reconstruction is based on an expanded signal model including the encoding effects of coil sensitivity, static off-resonance, and magnetic field dynamics. The latter are recorded concurrently with image acquisition, using NMR field probes. The resulting image resolution is assessed by point spread function analysis. Single-shot spiral imaging is achieved at a nominal resolution of 0.8 mm, using spiral-out readouts of 53-ms duration. High depiction fidelity is achieved without conspicuous blurring or distortion. Effective resolutions are assessed as 0.8, 0.94, and 0.98 mm in CSF, gray matter and white matter, respectively. High image quality is also achieved with half-shot acquisition yielding image pairs at 1.5-mm resolution. Use of an expanded signal model enables single-shot spiral imaging at 7 T with unprecedented image quality. Single-shot and half-shot spiral readouts deploy the sensitivity benefit of high field for rapid high-resolution imaging, particularly for functional MRI and arterial spin labeling. © 2018 International Society for Magnetic Resonance in Medicine.

  9. Configuration studies of LHD plasmas

    International Nuclear Information System (INIS)

    Okamoto, M.

    1997-01-01

    Configuration studies are performed on the plasmas of The Large Helical Device (LHD), the construction of which is almost completed at the National Institute for Fusion Science. The LHD has flexibility as an experimental device and can have various configurations by changing the poloidal magnetic fields, the pitch of the helical coils (pitch parameter), and the ratio of currents flowing in the two helical coils. Characteristics of the plasma are investigated for the standard configuration, the change in the pitch parameter, and the helical axis configuration

  10. Configuration studies of LHD plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Masao

    1997-03-01

    Configuration studies are performed on the plasmas of The Large Helical Device (LHD), the construction of which is almost completed at the National Institute for Fusion Science. The LHD has flexibility as an experimental device and can have various configurations by changing the poloidal magnetic fields, the pitch of the helical coils (pitch parameter), and the ratio of currents flowing in the two helical coils. Characteristics of the plasma are investigated for the standard configuration, the change in the pitch parameter, and the helical axis configuration. (author)

  11. Negative spiral CT in acute pulmonary embolism

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, T.; Olausson, A. [Karolinska Hospital, Stockholm (Sweden). Dept. of Thoracic Radiology; Johnsson, H. [Karolinska Hospital, Stockholm (Sweden). Dept. of Internal Medicine; Nyman, U. [County Hospital, Trelleborg (Sweden). Dept. of Radiology; Aspelin, P. [Huddinge Univ. Hospital (Sweden). Dept. of Radiology

    2002-09-01

    Purpose: To retrospectively evaluate the clinical outcome of non-anticoagulated patients with clinically suspected acute pulmonary embolism (PE) and no symptoms or signs of deep venous thrombosis (DVT) following a negative contrast medium-enhanced spiral CT of the pulmonary arteries (s-CTPA). Material and Methods: During a 24-month period, 739 of 751 patients underwent s-CTPA with acceptable diagnostic quality for clinically suspected acute PE. All patients who had a CT study not positive for PE were followed up with a questionnaire, a telephone interview and review of all medical reports, including autopsies and death certificates for any episodes of venous thromboembolism (VTE) during a 3-month period. Results: PE was diagnosed in 158 patients. Of the remaining 581 patients with a negative s-CTPA, 45 patients were lost to follow-up. 88 patients were excluded because of anticoagulation treatment (cardiac disorder n=32, chronic VTE or acute symptomatic DVT n=31, PE diagnosed at pulmonary angiography n=1, thrombus prophylaxis during diagnostic work-up or other reasons than VTE n=24) and 7 patients undergoing lower extremity venous studies because of symptoms of DVT (all negative). Thus, 441 patients with a negative s-CTPA and no DVT symptoms, venous studies or anticoagulant treatment constituted the follow-up cohort. Four of these patients had proven VTE (all PE) during the 3-month follow-up period. Two of the PE episodes contributed to the patient's death. Conclusion: Patients with clinically suspected acute PE, no symptoms or signs of DVT and a negative single slice s-CTPA using 3-5 mm collimation, may safely be left without anticoagulation treatment unless they are critically ill, have a limited cardiopulmonary reserve and/or if a high clinical suspicion remains.

  12. CHARACTERIZING SPIRAL ARM AND INTERARM STAR FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Kreckel, K.; Schinnerer, E.; Meidt, S. [Max Planck Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Blanc, G. A. [Departamento de Astronomía, Universidad de Chile, Camino del Observatorio 1515, Las Condes, Santiago (Chile); Groves, B. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Adamo, A. [Department of Astronomy, The Oskar Klein Centre, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden); Hughes, A., E-mail: kreckel@mpia.de [CNRS, IRAP, 9 Av. du Colonel Roche, BP 44346, F-31028 Toulouse cedex 4 (France)

    2016-08-20

    Interarm star formation contributes significantly to a galaxy’s star formation budget and provides an opportunity to study stellar birthplaces unperturbed by spiral arm dynamics. Using optical integral field spectroscopy of the nearby galaxy NGC 628 with VLT/MUSE, we construct H α maps including detailed corrections for dust extinction and stellar absorption to identify 391 H ii regions at 35 pc resolution over 12 kpc{sup 2}. Using tracers sensitive to the underlying gravitational potential, we associate H ii regions with either arm (271) or interarm (120) environments. Using our full spectral coverage of each region, we find that most physical properties (luminosity, size, metallicity, ionization parameter) of H ii regions are independent of environment. We calculate the fraction of H α luminosity due to the background of diffuse ionized gas (DIG) contaminating each H ii region, and find the DIG surface brightness to be higher within H ii regions than in the surroundings, and slightly higher within arm H ii regions. Use of the temperature-sensitive [S ii]/H α line ratio instead of the H α surface brightness to identify the boundaries of H ii regions does not change this result. Using the dust attenuation as a tracer of the gas, we find depletion times consistent with previous work (2 × 10{sup 9} yr) with no differences between the arm and interarm, but this is very sensitive to the DIG correction. Unlike molecular clouds, which can be dynamically affected by the galactic environment, we see fairly consistent properties of H ii regions in both arm and interarm environments. This suggests either a difference in star formation and feedback in arms or a decoupling of dense star-forming clumps from the more extended surrounding molecular gas.

  13. Two-dimensional liquid chromatography consisting of twelve second-dimension columns for comprehensive analysis of intact proteins.

    Science.gov (United States)

    Ren, Jiangtao; Beckner, Matthew A; Lynch, Kyle B; Chen, Huang; Zhu, Zaifang; Yang, Yu; Chen, Apeng; Qiao, Zhenzhen; Liu, Shaorong; Lu, Joann J

    2018-05-15

    A comprehensive two-dimensional liquid chromatography (LCxLC) system consisting of twelve columns in the second dimension was developed for comprehensive analysis of intact proteins in complex biological samples. The system consisted of an ion-exchange column in the first dimension and the twelve reverse-phase columns in the second dimension; all thirteen columns were monolithic and prepared inside 250 µm i.d. capillaries. These columns were assembled together through the use of three valves and an innovative configuration. The effluent from the first dimension was continuously fractionated and sequentially transferred into the twelve second-dimension columns, while the second-dimension separations were carried out in a series of batches (six columns per batch). This LCxLC system was tested first using standard proteins followed by real-world samples from E. coli. Baseline separation was observed for eleven standard proteins and hundreds of peaks were observed for the real-world sample analysis. Two-dimensional liquid chromatography, often considered as an effective tool for mapping proteins, is seen as laborious and time-consuming when configured offline. Our online LCxLC system with increased second-dimension columns promises to provide a solution to overcome these hindrances. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. An unusual giant spiral arc in the polar cap region during the northward phase of a Coronal Mass Ejection

    Directory of Open Access Journals (Sweden)

    L. Rosenqvist

    2007-03-01

    Full Text Available The shock arrival of an Interplanetary Coronal Mass Ejection (ICME at ~09:50 UT on 22 November 1997 resulted in the development of an intense (Dst<−100 nT geomagnetic storm at Earth. In the early, quiet phase of the storm, in the sheath region of the ICME, an unusual large spiral structure (diameter of ~1000 km was observed at very high latitudes by the Polar UVI instrument. The evolution of this structure started as a polewardly displaced auroral bulge which further developed into the spiral structure spreading across a large part of the polar cap. This study attempts to examine the cause of the chain of events that resulted in the giant auroral spiral. During this period the interplanetary magnetic field (IMF was dominantly northward (Bz>25 nT with a strong duskward component (By>15 nT resulting in a highly twisted tail plasma sheet. Geotail was located at the equatorial dawnside magnetotail flank and observed accelerated plasma flows exceeding the solar wind bulk velocity by almost 60%. These flows are observed on the magnetosheath side of the magnetopause and the acceleration mechanism is proposed to be typical for strongly northward IMF. Identified candidates to the cause of the spiral structure include a By induced twisted magnetotail configuration, the development of magnetopause surface waves due to the enhanced pressure related to the accelerated magnetosheath flows aswell as the formation of additional magnetopause deformations due to external solar wind pressure changes. The uniqeness of the event indicate that most probably a combination of the above effects resulted in a very extreme tail topology. However, the data coverage is insufficient to fully investigate the physical mechanism behind the observations.

  15. Stabilization of spiral wave and turbulence in the excitable media using parameter perturbation scheme

    International Nuclear Information System (INIS)

    Ma Jun; Wang Chunni; Li Yanlong; Pu Zhongsheng; Jin Wuyin

    2008-01-01

    This paper proposes a scheme of parameter perturbation to suppress the stable rotating spiral wave, meandering spiral wave and turbulence in the excitable media, which is described by the modified Fitzhugh–Nagumo (MFHN) model. The controllable parameter in the MFHN model is perturbed with a weak pulse and the pulse period is decided by the rotating period of the spiral wave approximatively. It is confirmed that the spiral wave and spiral turbulence can be suppressed greatly. Drift and instability of spiral wave can be observed in the numerical simulation tests before the whole media become homogeneous finally. (general)

  16. Can cluster environment modify the dynamical evolution of spiral galaxies?

    Science.gov (United States)

    Amram, P.; Balkowski, C.; Cayatte, V.; Marcelin, M.; Sullivan, W. T., III

    1993-01-01

    Over the past decade many effects of the cluster environment on member galaxies have been established. These effects are manifest in the amount and distribution of gas in cluster spirals, the luminosity and light distributions within galaxies, and the segregation of morphological types. All these effects could indicate a specific dynamical evolution for galaxies in clusters. Nevertheless, a more direct evidence, such as a different mass distribution for spiral galaxies in clusters and in the field, is not yet clearly established. Indeed, Rubin, Whitmore, and Ford (1988) and Whitmore, Forbes, and Rubin (1988) (referred to as RWF) presented evidence that inner cluster spirals have falling rotation curves, unlike those of outer cluster spirals or the great majority of field spirals. If falling rotation curves exist in centers of clusters, as argued by RWF, it would suggest that dark matter halos were absent from cluster spirals, either because the halos had become stripped by interactions with other galaxies or with an intracluster medium, or because the halos had never formed in the first place. Even if they didn't disagree with RWF, other researchers pointed out that the behaviour of the slope of the rotation curves of spiral galaxies (in Virgo) is not so clear. Amram, using a different sample of spiral galaxies in clusters, found only 10% of declining rotation curves (2 declining vs 17 flat or rising) in opposition to RWF who find about 40% of declining rotation curves in their sample (6 declining vs 10 flat or rising), we will hereafter briefly discuss the Amram data paper and compare it to the results of RWF. We have measured the rotation curves for a sample of 21 spiral galaxies in 5 nearby clusters. These rotation curves have been constructed from detailed two-dimensional maps of each galaxy's velocity field as traced by emission from the Ha line. This complete mapping, combined with the sensitivity of our CFHT 3.60 m. + Perot-Fabry + CCD observations, allows

  17. Strengthening of defected beam–column joints using CFRP

    Directory of Open Access Journals (Sweden)

    Mohamed H. Mahmoud

    2014-01-01

    Full Text Available This paper presents an experimental study for the structural performance of reinforced concrete (RC exterior beam–column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP. The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam–column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity.

  18. Strengthening of defected beam-column joints using CFRP.

    Science.gov (United States)

    Mahmoud, Mohamed H; Afefy, Hamdy M; Kassem, Nesreen M; Fawzy, Tarek M

    2014-01-01

    This paper presents an experimental study for the structural performance of reinforced concrete (RC) exterior beam-column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP). The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam-column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM) CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity.

  19. On wave dark matter in spiral and barred galaxies

    International Nuclear Information System (INIS)

    Martinez-Medina, Luis A.; Matos, Tonatiuh; Bray, Hubert L.

    2015-01-01

    We recover spiral and barred spiral patterns in disk galaxy simulations with a Wave Dark Matter (WDM) background (also known as Scalar Field Dark Matter (SFDM), Ultra-Light Axion (ULA) dark matter, and Bose-Einstein Condensate (BEC) dark matter). Here we show how the interaction between a baryonic disk and its Dark Matter Halo triggers the formation of spiral structures when the halo is allowed to have a triaxial shape and angular momentum. This is a more realistic picture within the WDM model since a non-spherical rotating halo seems to be more natural. By performing hydrodynamic simulations, along with earlier test particles simulations, we demonstrate another important way in which wave dark matter is consistent with observations. The common existence of bars in these simulations is particularly noteworthy. This may have consequences when trying to obtain information about the dark matter distribution in a galaxy, the mere presence of spiral arms or a bar usually indicates that baryonic matter dominates the central region and therefore observations, like rotation curves, may not tell us what the DM distribution is at the halo center. But here we show that spiral arms and bars can develop in DM dominated galaxies with a central density core without supposing its origin on mechanisms intrinsic to the baryonic matter

  20. Spiral CT findings of inflammatory pseudotumor of the liver

    International Nuclear Information System (INIS)

    Lee, Ha Jong; Nam, Kyung Jin; Lee, Ki Nam; Park, Byeong Ho; Choi, Jong Cheol; Koo, Bong Sik; Nam, Ki Dong; Kim, Chan Seong

    1998-01-01

    To assess the spiral CT findings of inflammatory pseudotumor of the liver(IPTL), in order to distinguish this tumor from hepatocellular carcinoma, hepatic abscess or other space occupying liver lesions. The spiral CT findings of IPTL were retrospectively evaluated in six patients. All cases were confirmed by ultrasonography-guided gun biopsy. Four patients were men and two were women, and they were aged between 37 and 74 (mean, 49) years. The site, size, and number of IPTL were assessed, and their enhancement patterns were evaluated during the arterial, portal and delayed phases of spiral CT. Five cases involved a solitary mass and in one there were multiple masses with surrounding small nodules. Four cases occurred in the right lobe and two in the left lobe. Four of five surrounding nodules were in the left lobe. During the arterial phase of spiral CT scanning, three layers were separated from four of five cases of solitary mass;they were composed of central and peripheral portions of low attenuation, and an intermediate portion of isoattenuation. Delayed enhancement of the peripheral portion was prominent during the delayed phase. In the case involving multiple masses three layers were not seen during the arterial phase, but during the delayed phase enhancement was noted. The features of three layers, as seen on spiral CT, is considered to be very specific for distinguishing IPTL from other hepatic focal lesions.=20

  1. A spiral-based volumetric acquisition for MR temperature imaging.

    Science.gov (United States)

    Fielden, Samuel W; Feng, Xue; Zhao, Li; Miller, G Wilson; Geeslin, Matthew; Dallapiazza, Robert F; Elias, W Jeffrey; Wintermark, Max; Butts Pauly, Kim; Meyer, Craig H

    2018-06-01

    To develop a rapid pulse sequence for volumetric MR thermometry. Simulations were carried out to assess temperature deviation, focal spot distortion/blurring, and focal spot shift across a range of readout durations and maximum temperatures for Cartesian, spiral-out, and retraced spiral-in/out (RIO) trajectories. The RIO trajectory was applied for stack-of-spirals 3D imaging on a real-time imaging platform and preliminary evaluation was carried out compared to a standard 2D sequence in vivo using a swine brain model, comparing maximum and mean temperatures measured between the two methods, as well as the temporal standard deviation measured by the two methods. In simulations, low-bandwidth Cartesian trajectories showed substantial shift of the focal spot, whereas both spiral trajectories showed no shift while maintaining focal spot geometry. In vivo, the 3D sequence achieved real-time 4D monitoring of thermometry, with an update time of 2.9-3.3 s. Spiral imaging, and RIO imaging in particular, is an effective way to speed up volumetric MR thermometry. Magn Reson Med 79:3122-3127, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  2. Propagating star formation and irregular structure in spiral galaxies

    International Nuclear Information System (INIS)

    Mueller, M.W.; Arnett, W.D.

    1976-01-01

    A simple model is proposed which describes the irregular optical appearance often seen in late-type spiral galaxies. If high-mass stars produce spherical shock waves which induce star formation, new high-mass stars will be born which, in turn, produce new shock waves. When this process operates in a differentially rotating disk, our numerical model shows that large-scale spiral-shaped regions of star formation are built up. The structure is seen to be most sensitive to a parameter which governs how often a region of the interstellar medium can undergo star formation. For a proper choice of this parameter, large-scale features disappear before differential rotation winds them up. New spiral features continuously form, so some spiral structure is seen indefinitely. The structure is not the classical two-armed symmetric spiral pattern which the density-wave theory attempts to explain, but it is asymmetric and disorderly.The mechanism of propagating star formation used in our model is consistent with observations which connect young OB associations with expanding shells of gas. We discuss the possible interaction of this mechanism with density waves

  3. Spiral scan long object reconstruction through PI line reconstruction

    International Nuclear Information System (INIS)

    Tam, K C; Hu, J; Sourbelle, K

    2004-01-01

    The response of a point object in a cone beam (CB) spiral scan is analysed. Based on the result, a reconstruction algorithm for long object imaging in spiral scan cone beam CT is developed. A region-of-interest (ROI) of the long object is scanned with a detector smaller than the ROI, and a portion of it can be reconstructed without contamination from overlaying materials. The top and bottom surfaces of the ROI are defined by two sets of PI lines near the two ends of the spiral path. With this novel definition of the top and bottom ROI surfaces and through the use of projective geometry, it is straightforward to partition the cone beam image into regions corresponding to projections of the ROI, the overlaying objects or both. This also simplifies computation at source positions near the spiral ends, and makes it possible to reduce radiation exposure near the spiral ends substantially through simple hardware collimation. Simulation results to validate the algorithm are presented

  4. Continuing research on the classical spiraling photon model

    Science.gov (United States)

    Li, Hongrui

    2014-11-01

    Based no the classical spiraling photon model proposed by Hongrui Li, the laws of reflection, refraction of a single photon can be derived. Moreover, the polarization, total reflection, evanescent wave and Goos-Hanchen shift of a single photon can be elucidated. However, this photon model is still unfinished. Especially, the spiraling diameter of a photon is not definite. In this paper, the continuous research works on this new theory are reported. According to the facts that the diffraction limit of light and the smallest diameter of the focal spot of lenses are all equal to the wavelength λ of the light, we can get that the spiraling diameter of a photon equals to the wavelength λ, so we gain that the angle between the linear velocity of the spiraling photon υ and the component of the linear velocity in the forward direction υb is 45°, and the energy of a classical spiraling photon E = (1/2)mυ2 = (1/2)m2c2 = mc2. This coincides with Einstein's mass-energy relation. While it is obtained that the velocity of the evanescent wave in the vacuum is slower than the velocity of light in glass in straight line. In such a way, the optical fiber can slow the light down. In addition, the force analysis of a single photon in optical tweezers system is discussed. And the reason that the laser beam can capture the particle slightly downstream from the focal point can be explained.

  5. Evaluation of Packed Distillation Columns I - Atmospheric Pressure

    National Research Council Canada - National Science Library

    Reynolds, Thaine

    1951-01-01

    .... Four column-packing combinations of the glass columns and four column-packing combinations of the steel columns were investigated at atmospheric pressure using a test mixture of methylcyclohexane...

  6. Configurational entropy of glueball states

    Energy Technology Data Exchange (ETDEWEB)

    Bernardini, Alex E., E-mail: alexeb@ufscar.br [Departamento de Física, Universidade Federal de São Carlos, PO Box 676, 13565-905, São Carlos, SP (Brazil); Braga, Nelson R.F., E-mail: braga@if.ufrj.br [Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, RJ 21941-972 (Brazil); Rocha, Roldão da, E-mail: roldao.rocha@ufabc.edu.br [CMCC, Universidade Federal do ABC, UFABC, 09210-580, Santo André (Brazil)

    2017-02-10

    The configurational entropy of glueball states is calculated using a holographic description. Glueball states are represented by a supergravity dual picture, consisting of a 5-dimensional graviton–dilaton action of a dynamical holographic AdS/QCD model. The configurational entropy is studied as a function of the glueball spin and of the mass, providing information about the stability of the glueball states.

  7. Oscillating water column structural model

    Energy Technology Data Exchange (ETDEWEB)

    Copeland, Guild [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jepsen, Richard Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gordon, Margaret Ellen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    An oscillating water column (OWC) wave energy converter is a structure with an opening to the ocean below the free surface, i.e. a structure with a moonpool. Two structural models for a non-axisymmetric terminator design OWC, the Backward Bent Duct Buoy (BBDB) are discussed in this report. The results of this structural model design study are intended to inform experiments and modeling underway in support of the U.S. Department of Energy (DOE) initiated Reference Model Project (RMP). A detailed design developed by Re Vision Consulting used stiffeners and girders to stabilize the structure against the hydrostatic loads experienced by a BBDB device. Additional support plates were added to this structure to account for loads arising from the mooring line attachment points. A simplified structure was designed in a modular fashion. This simplified design allows easy alterations to the buoyancy chambers and uncomplicated analysis of resulting changes in buoyancy.

  8. Demonstration of motionless Knudsen pump based micro-gas chromatography featuring micro-fabricated columns and on-column detectors.

    Science.gov (United States)

    Liu, Jing; Gupta, Naveen K; Wise, Kensall D; Gianchandani, Yogesh B; Fan, Xudong

    2011-10-21

    This paper reports the investigation of a micro-gas chromatography (μGC) system that utilizes an array of miniaturized motionless Knudsen pumps (KPs) as well as microfabricated separation columns and optical detectors. A prototype system was built to achieve a flow rate of 1 mL min(-1) and 0.26 mL min(-1) for helium and dry air, respectively, when they were used as carrier gas. This system was then employed to evaluate GC performance compromises and demonstrate the ability to separate and detect gas mixtures containing analytes of different volatilities and polarities. Furthermore, the use of pressure programming of the KP array was demonstrated to significantly shorten the analysis time while maintaining a high detection resolution. Using this method, we obtained a high resolution detection of 5 alkanes of different volatilities within 5 min. Finally, we successfully detected gas mixtures of various polarities using a tandem-column μGC configuration by installing two on-column optical detectors to obtain complementary chromatograms.

  9. Geometrical study of phyllotactic patterns by Bernoulli spiral lattices.

    Science.gov (United States)

    Sushida, Takamichi; Yamagishi, Yoshikazu

    2017-06-01

    Geometrical studies of phyllotactic patterns deal with the centric or cylindrical models produced by ideal lattices. van Iterson (Mathematische und mikroskopisch - anatomische Studien über Blattstellungen nebst Betrachtungen über den Schalenbau der Miliolinen, Verlag von Gustav Fischer, Jena, 1907) suggested a centric model representing ideal phyllotactic patterns as disk packings of Bernoulli spiral lattices and presented a phase diagram now called Van Iterson's diagram explaining the bifurcation processes of their combinatorial structures. Geometrical properties on disk packings were shown by Rothen & Koch (J. Phys France, 50(13), 1603-1621, 1989). In contrast, as another centric model, we organized a mathematical framework of Voronoi tilings of Bernoulli spiral lattices and showed mathematically that the phase diagram of a Voronoi tiling is graph-theoretically dual to Van Iterson's diagram. This paper gives a review of two centric models for disk packings and Voronoi tilings of Bernoulli spiral lattices. © 2017 Japanese Society of Developmental Biologists.

  10. Extending the GANIL control system for the SPIRAL project

    International Nuclear Information System (INIS)

    Lecorche, E.

    1997-01-01

    The SPIRAL project under construction at GANIL aims to deliver radioactive ion beams to the physicists by the end of 1998. In 1996, it has been proposed to achieve most of the SPIRAL control system as an extension of the system currently in use at GANIL. Therefore the main features of the GANIL control system design are first recalled. Then the paper shows how the GANIL control system should have been upgraded and extended to integrate the SPIRAL project. This evolution had to cope with the specific needs brought by the new machine and to consider the size of the project which is around one third of the GANIL control system volume. Lastly current status of the system is given. (author)

  11. Kinematical and dynamical models for barred spiral galaxies

    International Nuclear Information System (INIS)

    Davoust, E.

    1983-01-01

    This is a review of published works on the kinematics and dynamics of stellar bars and barred spiral galaxies. The periodic orbits of stars are elongated along the bar and enhance it out to a certain distance from the center. The important role of the interstellar gas is pointed out by the models of gas clouds and flows: the trajectories are also along the bar, but shock waves arise in front of the bar and transient spiral structures appear at its ends. These models reproduce the observed velocity fields fairly well. The investigations of the stability of axisymmetric galactic disks show that they are very unstable with respect to bar shaped perturbations and might explain why two thirds of the known spiral galaxies are barred [fr

  12. Vascular imaging with spiral CT. The way to CY angiography

    International Nuclear Information System (INIS)

    Prokop, M.; Schaefer, C.; Kalender, W.A.; Polacin, A.; Galanski, M.

    1993-01-01

    Spiral CT is a technique that allows for high-quality two-dimensional angiographic projections and 3D imaging of vascular structures. The authors present the technical and methodological principles of the technique, including scan parameters and parameters of contrast application for various clinical imaging tasks. They present their experience with over 150 clinical cases using spiral CT angiography. Suitable applications of this technique include cogenital anomalies, aneurysms, dissections, stenoses, thrombi and vascular tumor involvement. Given a problem-adapted examination technique, pathologic changes in vessels of as little as 2 mm can be visualized. In some cases with complex vascular anatomy, spiral CT angiography can be superior to arterial angiography. (orig.) [de

  13. Extending the GANIL control system for the SPIRAL project

    Energy Technology Data Exchange (ETDEWEB)

    Lecorche, E

    1997-12-31

    The SPIRAL project under construction at GANIL aims to deliver radioactive ion beams to the physicists by the end of 1998. In 1996, it has been proposed to achieve most of the SPIRAL control system as an extension of the system currently in use at GANIL. Therefore the main features of the GANIL control system design are first recalled. Then the paper shows how the GANIL control system should have been upgraded and extended to integrate the SPIRAL project. This evolution had to cope with the specific needs brought by the new machine and to consider the size of the project which is around one third of the GANIL control system volume. Lastly current status of the system is given. (author) 5 refs.

  14. Auditory Mechanics of the Tectorial Membrane and the Cochlear Spiral

    Science.gov (United States)

    Gavara, Núria; Manoussaki, Daphne; Chadwick, Richard S.

    2012-01-01

    Purpose of review This review is timely and relevant since new experimental and theoretical findings suggest that cochlear mechanics from the nanoscale to the macroscale are affected by mechanical properties of the tectorial membrane and the spiral shape. Recent findings Main tectorial membrane themes covered are i) composition and morphology, ii) nanoscale mechanical interactions with the outer hair cell bundle, iii) macroscale longitudinal coupling, iv) fluid interaction with inner hair cell bundles, v) macroscale dynamics and waves. Main cochlear spiral themes are macroscale low-frequency energy focusing and microscale organ of Corti shear gain. Implications Findings from new experimental and theoretical models reveal exquisite sensitivity of cochlear mechanical performance to tectorial membrane structural organization, mechanics, and its positioning with respect to hair bundles. The cochlear spiral geometry is a major determinant of low frequency hearing. Suggestions are made for future research directions. PMID:21785353

  15. Visibility in a pure model of golden spiral phyllotaxis.

    Science.gov (United States)

    Herrmann, Burghard

    2018-07-01

    This paper considers the geometry of plants with golden spiral phyllotaxis, i.e. growing leaf by leaf on a spiral with golden divergence angle, via the simplest mathematical model, a cylinder with regular arrangement of points on its surface. As is well-known, Fibonacci numbers appear by means of the order of parastichies. This fact is shown to be a straightforward application of logical consequences to a particular model with respect to pure visibility. This notion is very similar to that of contact parastichies. The 3-D cylindrical model of golden spiral phyllotaxis abstracts from the form of leaves and identifies them with points. Pure visibility is specified in the 2-D representation so that common sense parastichies can be scrutinized. The main Theorem states that the orders of the purely most visible parastichies are Fibonacci numbers. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Shunt impedance of spiral loaded resonant rf cavities

    International Nuclear Information System (INIS)

    Peebles, P.Z. Jr.; Parvarandeh, M.

    1975-01-01

    Based upon a treatment of the spiral loaded resonant radio frequency cavity as a shorted quarter-wave transmission line, a model for shunt impedance is developed. The model is applicable to loosely wound spirals in large diameter containers. Theoretical shunt impedance is given for spirals wound from tubing of circular or rectangular cross section. The former produces higher shunt impedance. Measurements made at Oak Ridge National Laboratory on 17 copper cavities are described which support the theoretical results. Theoretical results are also compared to data from twenty-three additional cavities measured at Los Alamos Scientific Laboratory. It is shown that the theoretical function forms a useful means of interpreting the quality of constructed cavities. (author)

  17. Global spiral structure of M81 - radio continuum maps

    International Nuclear Information System (INIS)

    Bash, F.N.; Kaufman, M.; Ohio State Univ., Columbus)

    1986-01-01

    VLA observations of the radio continuum emission from M81 at 6 and 20 cm are presented and used to check the predictions of density-wave theories. Both thermal and nonthermal radiation from the spiral arms are detected. Most of the bright knots along the radio arms are giant radio H II regions. The nonthermal emission defines spiral arms that are patchy and well-resolved, with a width of 1-2 kpc. The observed nonthermal arms are too broad to agree with the continuum gasdynamical calculations of Roberts (1969), Shu et al. (1972), and Visser (1978, 1980) for a classical density wave model. The observed arm widths appear consistent with the predictions of density-wave models that emphasize the clumpy nature of the ISM. The 20 cm arms appear to spiral outward from a faint inner H I ring, suggesting that the ring is produced by the inner Lindblad resonance. 36 references

  18. Simulation algorithm for spiral case structure in hydropower station

    Directory of Open Access Journals (Sweden)

    Xin-yong Xu

    2013-04-01

    Full Text Available In this study, the damage-plasticity model for concrete that was verified by the model experiment was used to calculate the damage to a spiral case structure based on the damage mechanics theory. The concrete structure surrounding the spiral case was simulated with a three-dimensional finite element model. Then, the distribution and evolution of the structural damage were studied. Based on investigation of the change of gap openings between the steel liner and concrete structure, the impact of the non-uniform variation of gaps on the load-bearing ratio between the steel liner and concrete structure was analyzed. The comparison of calculated results of the simplified and simulation algorithms shows that the simulation algorithm is a feasible option for the calculation of spiral case structures. In addition, the shell-spring model was introduced for optimization analysis, and the results were reasonable.

  19. The scientific objectives of the SPIRAL 2 Project

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, D.; Adoui, L.; Angelis, G. de [GANIL, Grand Accelerateur National d' Ions Lourds, BP 55027, 14076 Caen cedex 5 (France)] (and others)

    2006-06-15

    The construction of SPIRAL 2 at GANIL will open completely new possibilities for parallel beam operation of the whole facility. The whole GANIL/SPIRAL/SPIRAL2 accelerator complex will allow for the simultaneous use of up to 5 different radioactive and stable beams. Several combinations of different beams delivered in parallel for experiments at low (keV/u), medium (few MeV/u) and high (up to 100 MeV/u) energies will be possible. Presently the GANIL/SPIRAL facility delivers about 60 weeks per year of stable and radioactive beams (up to 3 simultaneous beams). Thanks to SPIRAL 2 and the construction of a new beam line connecting the CIME cyclotron and the G1 and G2 experimental rooms the available beam time for experiments may be extended up to about 120 (up to 5 simultaneous beams) weeks per year. The chapters which follow a general introduction deal with the detailed questions to be addressed by experiments with the beams from SPIRAL2. In chapter 2 the many unanswered questions related to the structure of exotic nuclei are posed and the role of SPIRAL2 in answering them outlined. Chapter 3 deals with the dynamics and thermodynamics of asymmetric nuclear systems. Chapter 4 is concerned with questions of nuclear astrophysics which are intimately related to the properties of exotic nuclei. Chapter 5 indicates how the atomic nucleus can act as a laboratory for tests of the Standard model of Particle Physics and Chapter 6 shows how the production of intense fluxes of neutrons at SPIRAL2 make it an excellent tool to address both questions related to damage in materials of importance in nuclear installations and to the s- and r-processes of nucleosynthesis. In chapter 7 we turn to the application, of the radioactive beams from SPIRAL2 and the radionuclides produced by it, to study condensed matter and radiobiology. Finally in the eight and last chapter the reader can find an account of the historical development of the SPIRAL2 facility and this is followed by an outline of

  20. Flocculent and grand design spiral arm structure in cluster galaxies

    International Nuclear Information System (INIS)

    Elmegreen, D.M.

    1982-01-01

    A total of 829 spiral galaxies in 22 clusters having redshifts between z = 0.02 and 0.06 were classified according to the appearance of their spiral arm structures. The fraction of galaxies that have a grand design spiral structure was found to be higher among barred galaxies than among non-barred galaxies (at z = 0.02, 95 per cent of strongly barred galaxies have a grand design, compared with 67 per cent of non-barred or weakly barred galaxies). Cluster galaxies and distant non-cluster galaxies have the same fraction of grand design galaxies when resolution effects are considered. The grand design fraction among cluster galaxies is also similar to the fraction observed among nearby galaxies in binary systems and in groups. (author)

  1. The scientific objectives of the SPIRAL 2 Project

    International Nuclear Information System (INIS)

    Ackermann, D.; Adoui, L.; Angelis, G. de

    2006-06-01

    The construction of SPIRAL 2 at GANIL will open completely new possibilities for parallel beam operation of the whole facility. The whole GANIL/SPIRAL/SPIRAL2 accelerator complex will allow for the simultaneous use of up to 5 different radioactive and stable beams. Several combinations of different beams delivered in parallel for experiments at low (keV/u), medium (few MeV/u) and high (up to 100 MeV/u) energies will be possible. Presently the GANIL/SPIRAL facility delivers about 60 weeks per year of stable and radioactive beams (up to 3 simultaneous beams). Thanks to SPIRAL 2 and the construction of a new beam line connecting the CIME cyclotron and the G1 and G2 experimental rooms the available beam time for experiments may be extended up to about 120 (up to 5 simultaneous beams) weeks per year. The chapters which follow a general introduction deal with the detailed questions to be addressed by experiments with the beams from SPIRAL2. In chapter 2 the many unanswered questions related to the structure of exotic nuclei are posed and the role of SPIRAL2 in answering them outlined. Chapter 3 deals with the dynamics and thermodynamics of asymmetric nuclear systems. Chapter 4 is concerned with questions of nuclear astrophysics which are intimately related to the properties of exotic nuclei. Chapter 5 indicates how the atomic nucleus can act as a laboratory for tests of the Standard model of Particle Physics and Chapter 6 shows how the production of intense fluxes of neutrons at SPIRAL2 make it an excellent tool to address both questions related to damage in materials of importance in nuclear installations and to the s- and r-processes of nucleosynthesis. In chapter 7 we turn to the application, of the radioactive beams from SPIRAL2 and the radionuclides produced by it, to study condensed matter and radiobiology. Finally in the eight and last chapter the reader can find an account of the historical development of the SPIRAL2 facility and this is followed by an outline of

  2. A Twin Spiral Planar Antenna for UWB Medical Radars

    Directory of Open Access Journals (Sweden)

    Giuseppe A. Zito

    2013-01-01

    Full Text Available A planar-spiral antenna to be used in an ultrawideband (UWB radar system for heart activity monitoring is presented. The antenna, named “twin,” is constituted by two spiral dipoles in a compact structure. The reflection coefficient at the feed point of the dipoles is lower than −8 dB over the 3–12 GHz band, while the two-dipoles coupling is about −20 dB. The radiated beam is perpendicular to the plane of the spiral, so the antenna is wearable and it may be an optimal radiator for a medical UWB radar for heart rate detection. The designed antenna has been also used to check some hypotheses about the UWB radar heart activity detection mechanism. The radiation impedance variation, caused by the thorax vibrations associated with heart activity, seems to be the most likely explanation of the UWB radar operation.

  3. The potentials of spiral CT for detection of focal liver lesions; Moeglichkeiten der Spiral-CT zur Diagnostik fokaler Leberlaesionen

    Energy Technology Data Exchange (ETDEWEB)

    Helmberger, H. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany); Kersting-Sommerhoff, B. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany); Lenz, M. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany); Kirsten, R. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany); Bautz, W. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany)

    1996-03-01

    Spiral CT currently is the modality of choice for all aspects of diagnostic evaluation of the liver. Optimal selection of treatment should be based inter alia on the findings obtained by spiral CT with arterial application of contrast medium, as for example S-CTA (primary liver tumors), or S-CTAP (secondary liver tumors). Ultrasonography is the major supplementing modality. In the near future, MR imaging applying liver-specific contrast-enhancing agents is expected to become an important competing technique, and further developments of interest in diagnostic imaging of the liver are in the offing: it is not yet known which technique will be the modality of choice at the onset of the 21st century. (orig.) [Deutsch] Die Spiral-CT ist zur Zeit das empfehlenswerte Verfahren fuer alle Fragen der Leberdiagnostik. Zur optimalen praetherapeutischen Beurteilung der Leber sollte die Spiral-CT mit arterieller Kontrastmittelapplikation als S-CTA (primaere Lebertumoren) bzw. S-CTAP (sekundaere Lebertumoren) durchgefuehrt werden. Der US kommt ein Stellenwert als ergaenzende Methode zu. In Zukunft wird die MRT mit leberspezifischen Kontrastmitteln ein konkurrierendes Verfahren zur Spiral-CT darstellen, wobei eine weitere interessante Entwicklung auf dem Gebiet der hepatischen Bildgebung zu erwarten ist: Das diagnostische Verfahren der Wahl fuer die Leber zu Beginn des 21. Jahrhunderts ist noch nicht definiert. (orig.)

  4. PROTOPLANETARY DISK HEATING AND EVOLUTION DRIVEN BY SPIRAL DENSITY WAVES

    Energy Technology Data Exchange (ETDEWEB)

    Rafikov, Roman R., E-mail: rrr@ias.edu [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)

    2016-11-10

    Scattered light imaging of protoplanetary disks often reveals prominent spiral arms, likely excited by massive planets or stellar companions. Assuming that these arms are density waves, evolving into spiral shocks, we assess their effect on the thermodynamics, accretion, and global evolution of the disk. We derive analytical expressions for the direct (irreversible) heating, angular momentum transport, and mass accretion rate induced by disk shocks of arbitrary amplitude. These processes are very sensitive to the shock strength. We show that waves of moderate strength (density jump at the shock ΔΣ/Σ ∼ 1) result in negligible disk heating (contributing at the ∼1% level to the energy budget) in passive, irradiated protoplanetary disks on ∼100 au scales, but become important within several au. However, shock heating is a significant (or even dominant) energy source in disks of cataclysmic variables, stellar X-ray binaries, and supermassive black hole binaries, heated mainly by viscous dissipation. Mass accretion induced by the spiral shocks is comparable to (or exceeds) the mass inflow due to viscous stresses. Protoplanetary disks featuring prominent global spirals must be evolving rapidly, in ≲0.5 Myr at ∼100 au. A direct upper limit on the evolution timescale can be established by measuring the gravitational torque due to the spiral arms from the imaging data. We find that, regardless of their origin, global spiral waves must be important agents of the protoplanetary disk evolution. They may serve as an effective mechanism of disk dispersal and could be related to the phenomenon of transitional disks.

  5. PROTOPLANETARY DISK HEATING AND EVOLUTION DRIVEN BY SPIRAL DENSITY WAVES

    International Nuclear Information System (INIS)

    Rafikov, Roman R.

    2016-01-01

    Scattered light imaging of protoplanetary disks often reveals prominent spiral arms, likely excited by massive planets or stellar companions. Assuming that these arms are density waves, evolving into spiral shocks, we assess their effect on the thermodynamics, accretion, and global evolution of the disk. We derive analytical expressions for the direct (irreversible) heating, angular momentum transport, and mass accretion rate induced by disk shocks of arbitrary amplitude. These processes are very sensitive to the shock strength. We show that waves of moderate strength (density jump at the shock ΔΣ/Σ ∼ 1) result in negligible disk heating (contributing at the ∼1% level to the energy budget) in passive, irradiated protoplanetary disks on ∼100 au scales, but become important within several au. However, shock heating is a significant (or even dominant) energy source in disks of cataclysmic variables, stellar X-ray binaries, and supermassive black hole binaries, heated mainly by viscous dissipation. Mass accretion induced by the spiral shocks is comparable to (or exceeds) the mass inflow due to viscous stresses. Protoplanetary disks featuring prominent global spirals must be evolving rapidly, in ≲0.5 Myr at ∼100 au. A direct upper limit on the evolution timescale can be established by measuring the gravitational torque due to the spiral arms from the imaging data. We find that, regardless of their origin, global spiral waves must be important agents of the protoplanetary disk evolution. They may serve as an effective mechanism of disk dispersal and could be related to the phenomenon of transitional disks.

  6. Picobubble enhanced column flotation of fine coal

    Energy Technology Data Exchange (ETDEWEB)

    Tao, D.; Yu, S.; Parekh, B.K. [University of Kentucky, Lexington, KY (United States). Mining Engineering

    2006-07-01

    The purpose is to study the effectiveness of picobubbles in the column flotation of -28 mesh fine coal particles. A flotation column with a picobubble generator was developed and tested for enhancing the recovery of ultrafine coal particles. The picobubble generator was designed using the hydrodynamic cavitation principle. A metallurgical and a steam coal were tested in the apparatus. The results show that the use of picobubbles in a 2in. flotation column increased the recovery of fine coal by 10 to 30%. The recovery rate varied with feed rate, collector dosage, and other column conditions. 40 refs., 8 figs., 2 tabs.

  7. Thermally stable dexsil-400 glass capillary columns

    International Nuclear Information System (INIS)

    Maskarinec, M.P.; Olerich, G.

    1980-01-01

    The factors affecting efficiency, thermal stability, and reproducibility of Dexsil-400 glass capillary columns for gas chromatography in general, and for polycyclic aromatic hydrocarbons (PAHs) in particular were investigated. Columns were drawn from Kimble KG-6 (soda-lime) glass or Kimox (borosilicate) glass. All silylation was carried out at 200 0 C. Columns were coated according to the static method. Freshly prepared, degassed solutions of Dexsil-400 in pentane or methylene chloride were used. Thermal stability of the Dexsil 400 columns with respect to gas chromatography/mass spectrometry (GC/MS) were tested. Column-to-column variability is a function of each step in the fabrication of the columns. The degree of etching, extent of silylation, and stationary phase film thickness must be carefully controlled. The variability in two Dexsil-400 capillary column prepared by etching, silylation with solution of hexa methyl disilazone (HMDS), and static coating is shown and also indicates the excellent selectivity of Dexsil-400 for the separation of alkylated aromatic compounds. The wide temperature range of Dexsil-400 and the high efficiency of the capillary columns also allow the analysis of complex mixtures with minimal prefractionation. Direct injection of a coal liquefaction product is given. Analysis by GC/MS indicated the presence of parent PAHs, alkylated PAHs, nitrogen and sulfur heterocycles, and their alkylated derivatives. 4 figures

  8. Laser surface wakefield in a plasma column

    International Nuclear Information System (INIS)

    Gorbunov, L.M.; Mora, P.; Ramazashvili, R.R.

    2003-01-01

    The structure of the wakefield in a plasma column, produced by a short intense laser pulse, propagating through a gas affected by tunneling ionization is investigated. It is shown that besides the usual plasma waves in the bulk part of the plasma column [see Andreev et al., Phys. Plasmas 9, 3999 (2002)], the laser pulse also generates electromagnetic surface waves propagating along the column boundary. The length of the surface wake wave substantially exceeds the length of the plasma wake wave and its electromagnetic field extends far outside the plasma column

  9. Initial clinical experience with spiral CT angiography in the abdomen

    International Nuclear Information System (INIS)

    Gaa, J.; Stehling, M.K.; Costello, P.

    1993-01-01

    The latest developments in modern CT instruments, offering scanning times of a second, opened up new possibilities in CT imaging in combination with the spiral technique. The data set normally taken with single-breath-hold technique is free of respiratory artefacts and thus is a good basis for accurate 3D image reconstruction. Spiral CTA allows a non-invasive 3D imaging of various blood vessels. Patients with abdominal aortic aneurysms of aorto-iliac bypass can be examined as outpatients within 15 minutes. (orig.) [de

  10. Rediscovering the Giant Low Surface Brightness Spiral Galaxy Malin 1

    Science.gov (United States)

    Galaz, Gaspar

    2018-01-01

    I summarize the latest discoveries regarding this ramarkable diffuse and giant galaxy, the largest single spiral in the universe so far. I describe how the latest discoveries could have been done easily 20 years ago, but an incredible summation of facts and some astronomical sociology, keeped many of them undisclosed. I present the most conspicuous features of the giant spiral arms of Malin 1, including stellar density, colors, stellar populations and some modeling describing their past evolution to the current state. I conclude with pending issues regarding stellar formation in Malin 1, and the efforts to detect its elusive molecular gas.

  11. Recent Advances in the Analysis of Spiral Bevel Gears

    Science.gov (United States)

    Handschuh, Robert F.

    1997-01-01

    A review of recent progress for the analysis of spiral bevel gears will be described. The foundation of this work relies on the description of the gear geometry of face-milled spiral bevel gears via the approach developed by Litvin. This methodology was extended by combining the basic gear design data with the manufactured surfaces using a differential geometry approach, and provides the data necessary for assembling three-dimensional finite element models. The finite element models have been utilized to conduct thermal and structural analysis of the gear system. Examples of the methods developed for thermal and structural/contact analysis are presented.

  12. Multiarm spirals on the periphery of disc galaxies

    Science.gov (United States)

    Lubov, Spiegel; Evgeny, Polyachenko

    2018-04-01

    Spiral patterns in some disc galaxies have two arms in the centre, and three or more arms on the periphery. The same result is also obtained in numerical simulations of stellar and gaseous discs.We argue that such patterns may occur due to fast cooling of the gas, resulting in formation of giant molecular clouds. The timescale of this process is 50 Myr, the factor of 10 shorter than of ordinary secular instability. The giant molecular clouds give rise to multiarm spirals through the mechanism of swing amplification.

  13. The color gradient in spiral galaxies: application to M 81

    International Nuclear Information System (INIS)

    Segalovitz, A.

    1975-01-01

    The calculated development of the color of a star cluster is used to predict the expected color evolution, as a function of radius, in a spiral galaxy. It is assumed that the fraction of gas which is converted into stars during a spiral arm passage is a function of radius only. Applying this model to M 81, it is shown that the observed color and mass distributions can be explained by an initial disk-like gas distribution proportional to the inverse square of the radius and a consumption fraction which is an increasing function of radius. (orig.) [de

  14. The Galactic Centre Mini-Spiral with CARMA

    Science.gov (United States)

    Kunneriath, D.; Eckart, A.; Vogel, S. N.; Teuben, P.; Muzic, K.; Schodel. R.; Garcia-Marin, M.; Moultaka, J.; Staguhn, J.; Straubmeier, C.; hide

    2012-01-01

    The Galactic centre mini-spiral region is a mixture of gas and dust with temperatures ranging from a few hundred K to 10(exp 4) K. We report results from 1.3 and 3mm radio interferometric observations of this region with CARMA, and present a spectral index map of this region. We find a range of emission mechanisms in the region, including the inverted synchrotron spectrum of Sgr A*, free-free emission from the mini-spiral arms, and a possible dust emission contribution indicated by a positive spectral index.

  15. SPIRAL2 Week 2011 - Slides of the presentations

    International Nuclear Information System (INIS)

    Gales, S.; Jacquemet, M.; Lewitowicz, M.; Petit, E.; Biarrote, J.L.; Uriot, D.; Thuillier, T.; Peaucelle, C.; Barue, C.; Van Hille, C.; Bernaudin, P.E.; Galdemard, P.; Ausset, P.; Dolegieviez, P.; Levallois, R.; Marchetto, M.; Pasini, M.; Quiclet, M.; Danna, O.; Lunney, D.; Di Giacomo, M.

    2013-01-01

    The main goal of the meeting is to present and discuss the current status of the SPIRAL2 project at GANIL in front of a large community of scientists and engineers. The program of the meeting will include presentations on scientific and technical developments related to the baseline project, experiments and theory. The main topics to be discussed at the conference have been: -) Driver Accelerators, -) Production of radioactive ion beams (RIB), -) Safety, -) RIB Facilities Worldwide (FAIR, Riken Nishina Center, SPES project, FRIB project) -) FP7 SPIRAL2 Preparatory Phase, -) Experiments with RIB and Theory. This document is made up of the slides of the presentations

  16. Resonant fields created by spiral electric currents in Tokamaks

    International Nuclear Information System (INIS)

    Fernandes, A.S.; Caldas, I.L.

    1985-01-01

    The influence of the resonant magnetic perturbations, created by electric currents in spirals, on the plasma confinement in a tokamak with circular section and large aspect ratio is investigated. These perturbations create magnetic islands around the rational magnetic surface which has the helicity of the helicoidal currents. The intensities of these currents are calculated in order to the magnetic islands reach the limiter or others rational surfaces, what could provoke the plasma disrupture. The electric current intensities are estimated, in two spiral sets with different helicities, which create a predominantly stocastic region among the rational magnetic surfaces with these helicities. (L.C.) [pt

  17. Viscous Design of TCA Configuration

    Science.gov (United States)

    Krist, Steven E.; Bauer, Steven X. S.; Campbell, Richard L.

    1999-01-01

    The goal in this effort is to redesign the baseline TCA configuration for improved performance at both supersonic and transonic cruise. Viscous analyses are conducted with OVERFLOW, a Navier-Stokes code for overset grids, using PEGSUS to compute the interpolations between overset grids. Viscous designs are conducted with OVERDISC, a script which couples OVERFLOW with the Constrained Direct Iterative Surface Curvature (CDISC) inverse design method. The successful execution of any computational fluid dynamics (CFD) based aerodynamic design method for complex configurations requires an efficient method for regenerating the computational grids to account for modifications to the configuration shape. The first section of this presentation deals with the automated regridding procedure used to generate overset grids for the fuselage/wing/diverter/nacelle configurations analysed in this effort. The second section outlines the procedures utilized to conduct OVERDISC inverse designs. The third section briefly covers the work conducted by Dick Campbell, in which a dual-point design at Mach 2.4 and 0.9 was attempted using OVERDISC; the initial configuration from which this design effort was started is an early version of the optimized shape for the TCA configuration developed by the Boeing Commercial Airplane Group (BCAG), which eventually evolved into the NCV design. The final section presents results from application of the Natural Flow Wing design philosophy to the TCA configuration.

  18. Classifying and modelling spiral structures in hydrodynamic simulations of astrophysical discs

    Science.gov (United States)

    Forgan, D. H.; Ramón-Fox, F. G.; Bonnell, I. A.

    2018-05-01

    We demonstrate numerical techniques for automatic identification of individual spiral arms in hydrodynamic simulations of astrophysical discs. Building on our earlier work, which used tensor classification to identify regions that were `spiral-like', we can now obtain fits to spirals for individual arm elements. We show this process can even detect spirals in relatively flocculent spiral patterns, but the resulting fits to logarithmic `grand-design' spirals are less robust. Our methods not only permit the estimation of pitch angles, but also direct measurements of the spiral arm width and pattern speed. In principle, our techniques will allow the tracking of material as it passes through an arm. Our demonstration uses smoothed particle hydrodynamics simulations, but we stress that the method is suitable for any finite-element hydrodynamics system. We anticipate our techniques will be essential to studies of star formation in disc galaxies, and attempts to find the origin of recently observed spiral structure in protostellar discs.

  19. Origin choice and petal loss in the flower garden of spiral wave tip trajectories.

    Science.gov (United States)

    Gray, Richard A; Wikswo, John P; Otani, Niels F

    2009-09-01

    Rotating spiral waves have been observed in numerous biological and physical systems. These spiral waves can be stationary, meander, or even degenerate into multiple unstable rotating waves. The spatiotemporal behavior of spiral waves has been extensively quantified by tracking spiral wave tip trajectories. However, the precise methodology of identifying the spiral wave tip and its influence on the specific patterns of behavior remains a largely unexplored topic of research. Here we use a two-state variable FitzHugh-Nagumo model to simulate stationary and meandering spiral waves and examine the spatiotemporal representation of the system's state variables in both the real (i.e., physical) and state spaces. We show that mapping between these two spaces provides a method to demarcate the spiral wave tip as the center of rotation of the solution to the underlying nonlinear partial differential equations. This approach leads to the simplest tip trajectories by eliminating portions resulting from the rotational component of the spiral wave.

  20. The Fundamental Structure and the Reproduction of Spiral Wave in a Two-Dimensional Excitable Lattice.

    Science.gov (United States)

    Qian, Yu; Zhang, Zhaoyang

    2016-01-01

    In this paper we have systematically investigated the fundamental structure and the reproduction of spiral wave in a two-dimensional excitable lattice. A periodically rotating spiral wave is introduced as the model to reproduce spiral wave artificially. Interestingly, by using the dominant phase-advanced driving analysis method, the fundamental structure containing the loop structure and the wave propagation paths has been revealed, which can expose the periodically rotating orbit of spiral tip and the charity of spiral wave clearly. Furthermore, the fundamental structure is utilized as the core for artificial spiral wave. Additionally, the appropriate parameter region, in which the artificial spiral wave can be reproduced, is studied. Finally, we discuss the robustness of artificial spiral wave to defects.

  1. Spiral model of the Galaxy from observations of the interstellar light attenuation

    International Nuclear Information System (INIS)

    Urasin, L.A.

    1987-01-01

    The model of two arms spiral structure of the Galaxy is made from the observations of space distribution of the interstellar dust matter. This model is the logarithmic spiral with characteristic angle (pith) 6.5 deg

  2. Analysis and seismic tests of composite shear walls with CFST columns and steel plate deep beams

    Science.gov (United States)

    Dong, Hongying; Cao, Wanlin; Wu, Haipeng; Zhang, Jianwei; Xu, Fangfang

    2013-12-01

    A composite shear wall concept based on concrete filled steel tube (CFST) columns and steel plate (SP) deep beams is proposed and examined in this study. The new wall is composed of three different energy dissipation elements: CFST columns; SP deep beams; and reinforced concrete (RC) strips. The RC strips are intended to allow the core structural elements — the CFST columns and SP deep beams — to work as a single structure to consume energy. Six specimens of different configurations were tested under cyclic loading. The resulting data are analyzed herein. In addition, numerical simulations of the stress and damage processes for each specimen were carried out, and simulations were completed for a range of location and span-height ratio variations for the SP beams. The simulations show good agreement with the test results. The core structure exhibits a ductile yielding mechanism characteristic of strong column-weak beam structures, hysteretic curves are plump and the composite shear wall exhibits several seismic defense lines. The deformation of the shear wall specimens with encased CFST column and SP deep beam design appears to be closer to that of entire shear walls. Establishing optimal design parameters for the configuration of SP deep beams is pivotal to the best seismic behavior of the wall. The new composite shear wall is therefore suitable for use in the seismic design of building structures.

  3. Spiral wave drift and complex-oscillatory spiral waves caused by heterogeneities in two-dimensional in vitro cardiac tissues

    International Nuclear Information System (INIS)

    Woo, Sung-Jae; Hong, Jin Hee; Kim, Tae Yun; Bae, Byung Wook; Lee, Kyoung J

    2008-01-01

    Understanding spiral reentry wave dynamics in cardiac systems is important since it underlies various cardiac arrhythmia including cardiac fibrillation. Primary cultures of dissociated cardiac cells have been a convenient and useful system for studying cardiac wave dynamics, since one can carry out systematic and quantitative studies with them under well-controlled environments. One key drawback of the dissociated cell culture is that, inevitably, some spatial inhomogeneities in terms of cell types and density, and/or the degree of gap junction connectivity, are introduced to the system during the preparation. These unintentional spatial inhomogeneities can cause some non-trivial wave dynamics, for example, the entrainment dynamics among different spiral waves and the generation of complex-oscillatory spiral waves. The aim of this paper is to quantify these general phenomena in an in vitro cardiac system and provide explanations for them with a simple physiological model having some realistic spatial inhomogeneities incorporated

  4. Stable configurations in social networks

    Science.gov (United States)

    Bronski, Jared C.; DeVille, Lee; Ferguson, Timothy; Livesay, Michael

    2018-06-01

    We present and analyze a model of opinion formation on an arbitrary network whose dynamics comes from a global energy function. We study the global and local minimizers of this energy, which we call stable opinion configurations, and describe the global minimizers under certain assumptions on the friendship graph. We show a surprising result that the number of stable configurations is not necessarily monotone in the strength of connection in the social network, i.e. the model sometimes supports more stable configurations when the interpersonal connections are made stronger.

  5. A Software Configuration Management Course

    DEFF Research Database (Denmark)

    Asklund, U.; Bendix, Lars Gotfred

    2003-01-01

    Software Configuration Management has been a big success in research and creation of tools. There are also many vendors in the market of selling courses to companies. However, in the education sector Software Configuration Management has still not quite made it - at least not into the university...... curriculum. It is either not taught at all or is just a minor part of a general course in software engineering. In this paper, we report on our experience with giving a full course entirely dedicated to Software Configuration Management topics and start a discussion of what ideally should be the goal...

  6. Device configuration-management system

    International Nuclear Information System (INIS)

    Nowell, D.M.

    1981-01-01

    The Fusion Chamber System, a major component of the Magnetic Fusion Test Facility, contains several hundred devices which report status to the Supervisory Control and Diagnostic System for control and monitoring purposes. To manage the large number of diversity of devices represented, a device configuration management system was required and developed. Key components of this software tool include the MFTF Data Base; a configuration editor; and a tree structure defining the relationships between the subsystem devices. This paper will describe how the configuration system easily accomodates recognizing new devices, restructuring existing devices, and modifying device profile information

  7. Measurement of Galactic Logarithmic Spiral Arm Pitch Angle Using Two-Dimensional Fast Fourier Transform Decomposition

    OpenAIRE

    Davis, Benjamin L.; Berrier, Joel C.; Shields, Douglas W.; Kennefick, Julia; Kennefick, Daniel; Seigar, Marc S.; Lacy, Claud H. S.; Puerari, Ivânio

    2012-01-01

    A logarithmic spiral is a prominent feature appearing in a majority of observed galaxies. This feature has long been associated with the traditional Hubble classification scheme, but historical quotes of pitch angle of spiral galaxies have been almost exclusively qualitative. We have developed a methodology, utilizing two-dimensional fast Fourier transformations of images of spiral galaxies, in order to isolate and measure the pitch angles of their spiral arms. Our technique provides a quanti...

  8. Airport Configuration Prediction, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — There is presently poor knowledge throughout the National Airspace System (NAS) of the airport configurations currently in use at each airport. There is even less...

  9. Belene NPP project configuration management

    International Nuclear Information System (INIS)

    Matveev, A.

    2009-01-01

    The configuration management includes: change identification; change assessment; change coordination; change approval or rejection; Change introduction. One of the main tasks while implementing the above processes is the analysis of the effect of one change upon all the related elements

  10. Smooth-arm spiral galaxies: their properties and significance to cluster-galaxy evolution

    International Nuclear Information System (INIS)

    Wilkerson, M.S.

    1979-01-01

    In this dissertation a number of galaxies with optical appearances between those of normal, actively-star-forming spirals and SO galaxies have been examined. These so-called smooth-arm spiral galaxies exhibit spiral arms without any of the spiral tracers - H II regions, O-B star associations, dust - indicative of current star formation. Tests were made to find if, perhaps, these smooth-arm spirals could have, at one time, been normal, actively-star-forming spirals whose gas had been somehow removed; and that are currently transforming into SO galaxies. This scenario proceeds as (1) removal of gas, (2) gradual dying of disk density wave, (3) emergence of SO galaxy. If the dominant method of gas removal is ram-pressure stripping by a hot, intracluster medium, then smooth-arm spirals should occur primarily in x-ray clusters. Some major findings of this dissertation are as follows: (1) Smooth-arm spirals are redder than normal spirals of the same morphological type. Most smooth-arm spirals cannot be distinguished by color from SO galaxies. (2) A weak trend exists for smooth-arm spirals with stronger arms to be bluer than those with weaker arms; thus implying that the interval since gas removal has been shorter for the galaxies with stronger arms. (3) Smooth-arm spirals are deficient in neutral hydrogen - sometimes by an order of magnitude or, possibly, more

  11. A Spiral Task as a Model for In-Service Teacher Education

    Science.gov (United States)

    Fried, Michael N.; Amit, Miriam

    2005-01-01

    The spiral approach has long been used by curriculum designers to deepen students' knowledge of scientific and mathematical concepts and to bring students to higher levels of abstraction. The benefits of a spiral approach, however, can also be extended to teacher education. This paper describes a spiral activity employed by the "Kidumatica"…

  12. Multi-Column Experimental Test Bed for Xe/Kr Separation

    International Nuclear Information System (INIS)

    Greenhalgh, Mitchell Randy; Garn, Troy Gerry; Welty, Amy Keil; Lyon, Kevin Lawrence; Watson, Tony Leroy

    2015-01-01

    Previous research studies have shown that INL-developed engineered form sorbents are capable of capturing both Kr and Xe from various composite gas streams. The previous experimental test bed provided single column testing for capacity evaluations over a broad temperature range. To advance research capabilities, the employment of an additional column to study selective capture of target species to provide a defined final gas composition for waste storage was warranted. The second column addition also allows for compositional analyses of the final gas product to provide for final storage determinations. The INL krypton capture system was modified by adding an additional adsorption column in order to create a multi-column test bed. The purpose of this modification was to investigate the separation of xenon from krypton supplied as a mixed gas feed. The extra column was placed in a Stirling Ultra-low Temperature Cooler, capable of controlling temperatures between 190 and 253K. Additional piping and valves were incorporated into the system to allow for a variety of flow path configurations. The new column was filled with the AgZ-PAN sorbent which was utilized as the capture medium for xenon while allowing the krypton to pass through. The xenon-free gas stream was then routed to the cryostat filled with the HZ-PAN sorbent to capture the krypton at 191K. Selectivities of xenon over krypton were determined using the new column to verify the system performance and to establish the operating conditions required for multi-column testing. Results of these evaluations verified that the system was operating as designed and also demonstrated that AgZ-PAN exhibits excellent selectivity for xenon over krypton in air at or near room temperature. Two separation tests were performed utilizing a feed gas consisting of 1000 ppmv xenon and 150 ppmv krypton with the balance being made up of air. The AgZ-PAN temperature was held at 295 or 253K while the HZ-PAN was held at 191K for both

  13. Column: Factors Affecting Data Decay

    Directory of Open Access Journals (Sweden)

    Kevin Fairbanks

    2012-06-01

    Full Text Available In nuclear physics, the phrase decay rate is used to denote the rate that atoms and other particles spontaneously decompose. Uranium-235 famously decays into a variety of daughter isotopes including Thorium and Neptunium, which themselves decay to others. Decay rates are widely observed and wildly different depending on many factors, both internal and external. U-235 has a half-life of 703,800,000 years, for example, while free neutrons have a half-life of 611 seconds and neutrons in an atomic nucleus are stable.We posit that data in computer systems also experiences some kind of statistical decay process and thus also has a discernible decay rate. Like atomic decay, data decay fluctuates wildly. But unlike atomic decay, data decay rates are the result of so many different interplaying processes that we currently do not understand them well enough to come up with quantifiable numbers. Nevertheless, we believe that it is useful to discuss some of the factors that impact the data decay rate, for these factors frequently determine whether useful data about a subject can be recovered by forensic investigation.(see PDF for full column

  14. Gaseous carbon dioxide absorbing column

    International Nuclear Information System (INIS)

    Harashina, Heihachi.

    1994-01-01

    The absorbing column of the present invention comprises a cyclone to which CO 2 gas and Ca(OH) 2 are blown to form CaCO 3 , a water supply means connected to an upper portion of the cyclone for forming a thin water membrane on the inner wall thereof, and a water processing means connected to a lower portion of the cyclone for draining water incorporating CaCO 3 . If a mixed fluid of CO 2 gas and Ca(OH) 2 is blown in a state where a flowing water membrane is formed on the inner wall of the cyclone, formation of CaCO 3 is promoted also in the inside of the cyclone in addition to the formation of CaCO 3 in the course of blowing. Then, formed CaCO 3 is discharged from the lower portion of the cyclone together with downwardly flowing water. With such procedures, solid contents such as CaCO 3 separated at the inner circumferential wall are sent into the thin water membrane, adsorbed and captured, and the solid contents are successively washed out, so that a phenomenon that the solid contents deposit and grow on the inner wall of the cyclone can be prevented effectively. (T.M.)

  15. Bayesian image restoration, using configurations

    OpenAIRE

    Thorarinsdottir, Thordis

    2006-01-01

    In this paper, we develop a Bayesian procedure for removing noise from images that can be viewed as noisy realisations of random sets in the plane. The procedure utilises recent advances in configuration theory for noise free random sets, where the probabilities of observing the different boundary configurations are expressed in terms of the mean normal measure of the random set. These probabilities are used as prior probabilities in a Bayesian image restoration approach. Estimation of the re...

  16. Electromagnetic scattering and radiation from microstrip patch antennas and spirals residing in a cavity

    Science.gov (United States)

    Volakis, J. L.; Gong, J.; Alexanian, A.; Woo, A.

    1992-01-01

    A new hybrid method is presented for the analysis of the scattering and radiation by conformal antennas and arrays comprised of circular or rectangular elements. In addition, calculations for cavity-backed spiral antennas are given. The method employs a finite element formulation within the cavity and the boundary integral (exact boundary condition) for terminating the mesh. By virtue of the finite element discretization, the method has no restrictions on the geometry and composition of the cavity or its termination. Furthermore, because of the convolutional nature of the boundary integral and the inherent sparseness of the finite element matrix, the storage requirement is kept very low at O(n). These unique features of the method have already been exploited in other scattering applications and have permitted the analysis of large-size structures with remarkable efficiency. In this report, we describe the method's formulation and implementation for circular and rectangular patch antennas in different superstrate and substrate configurations which may also include the presence of lumped loads and resistive sheets/cards. Also, various modelling approaches are investigated and implemented for characterizing a variety of feed structures to permit the computation of the input impedance and radiation pattern. Many computational examples for rectangular and circular patch configurations are presented which demonstrate the method's versatility, modeling capability and accuracy.

  17. Rasch models with exchangeable rows and columns

    DEFF Research Database (Denmark)

    Lauritzen, Steffen Lilholt

    The article studies distributions of doubly infinite binary matrices with exchangeable rows and columns which satify the further property that the probability of any $m \\times n$ submatrix is a function of the row- and column sums of that matrix. We show that any such distribution is a (unique...

  18. The general packed column : an analytical solution

    NARCIS (Netherlands)

    Gielen, J.L.W.

    2000-01-01

    The transient behaviour of a packed column is considered. The column, uniformly packed on a macroscopic scale, is multi-structured on the microscopic level: the solid phase consists of particles, which may differ in incidence, shape or size, and other relevant physical properties. Transport in the

  19. Fringing-field effects in acceleration columns

    International Nuclear Information System (INIS)

    Yavor, M.I.; Weick, H.; Wollnik, H.

    1999-01-01

    Fringing-field effects in acceleration columns are investigated, based on the fringing-field integral method. Transfer matrices at the effective boundaries of the acceleration column are obtained, as well as the general transfer matrix of the region separating two homogeneous electrostatic fields with different field strengths. The accuracy of the fringing-field integral method is investigated

  20. Thermal Modeling Analysis Of CST Media In The Small Column Ion Exchange Project

    International Nuclear Information System (INIS)

    Lee, S.

    2010-01-01

    Models have been developed to simulate the thermal characteristics of Crystalline Silicotitanate (CST) ion exchange media fully loaded with radioactive cesium in a column configuration and distributed within a waste storage tank. This work was conducted to support the Small Column Ion Exchange (SCIX) program which is focused on processing dissolved, high-sodium salt waste for the removal of specific radionuclides (including Cs-137, Sr-90, and actinides) within a High Level Waste (HLW) storage tank at the Savannah River Site. The SCIX design includes CST columns inserted and supported in the tank top risers for cesium removal. Temperature distributions and maximum temperatures across the column were calculated with a focus on process upset conditions. A two-dimensional computational modeling approach for the in-column ion-exchange domain was taken to include conservative, bounding estimates for key parameters such that the results would provide the maximum centerline temperatures achievable under the design configurations using a feed composition known to promote high cesium loading on CST. One salt processing scenario includes the transport of the loaded (and possibly ground) CST media to the treatment tank floor. Therefore, additional thermal modeling calculations were conducted using a three-dimensional approach to evaluate temperature distributions for the entire in-tank domain including distribution of the spent CST media either as a mound or a flat layer on the tank floor. These calculations included mixtures of CST with HLW sludge or loaded Monosodium Titanate (MST) media used for strontium/actinide sorption. The current full-scale design for the CST column includes one central cooling pipe and four outer cooling tubes. Most calculations assumed that the fluid within the column was stagnant (i.e. no buoyancy-induced flow) for a conservative estimate. A primary objective of these calculations was to estimate temperature distributions across packed CST beds

  1. Hyperbolic functions with configuration theorems and equivalent and equidecomposable figures

    CERN Document Server

    Shervatov, V G; Skornyakov, L A; Boltyanskii, V G

    2007-01-01

    This single-volume compilation of three books centers on Hyperbolic Functions, an introduction to the relationship between the hyperbolic sine, cosine, and tangent, and the geometric properties of the hyperbola. The development of the hyperbolic functions, in addition to those of the trigonometric (circular) functions, appears in parallel columns for comparison. A concluding chapter introduces natural logarithms and presents analytic expressions for the hyperbolic functions.The second book, Configuration Theorems, requires only the most elementary background in plane and solid geometry. It dis

  2. Analysis of contour images using optics of spiral beams

    Science.gov (United States)

    Volostnikov, V. G.; Kishkin, S. A.; Kotova, S. P.

    2018-03-01

    An approach is outlined to the recognition of contour images using computer technology based on coherent optics principles. A mathematical description of the recognition process algorithm and the results of numerical modelling are presented. The developed approach to the recognition of contour images using optics of spiral beams is described and justified.

  3. The thickness of the HI gas layer in spiral galaxies

    NARCIS (Netherlands)

    Sicking, Floris Jan

    1997-01-01

    In the present study, in two inclined spiral galaxies, NGC 3198 and NGC 2403, the HI random velocity dispersion and layer thickness will be measured simultaneously. This will be done from the HI velocity dispersion field (the distribution on the sky of the observed HI line of sight velocity

  4. Dark matter and rotation curves of spiral galaxies

    Czech Academy of Sciences Publication Activity Database

    Křížek, Michal; Křížek, Filip; Somer, L.

    2016-01-01

    Roč. 25, April (2016), s. 64-77 ISSN 1313-2709 R&D Projects: GA MŠk(CZ) LG15052 Institutional support: RVO:67985840 ; RVO:61389005 Keywords : red dwarf * dark matter * spiral galaxy Subject RIV: BA - General Mathematics http://www.astro.bas.bg/AIJ/issues/n25/MKrizek.pdf

  5. Ultra wideband coplanar waveguide fed spiral antenna for humanitarian demining

    DEFF Research Database (Denmark)

    Thaysen, Jesper; Jakobsen, Kaj Bjarne; Appel-Hansen, Jørgen

    2000-01-01

    to 1 bandwidth with a return loss better than 10 dB from 0.4 to 3.8 GHz is presented. A wideband balun covering the frequency range of the antenna was developed. The constructed spiral antenna is very useful in a stepped frequency ground penetrating radar for humanitarian demining due to the very...

  6. Theory of the paraxial ion trajectory in the spiral inflector

    International Nuclear Information System (INIS)

    Toprek, Dragan

    2000-01-01

    This paper presents the analytical and numerical theory of the paraxial ion trajectory through the spiral inflector. Analytical expressions for the equations which describe the paraxial ion trajectory are derived. The analytical derivations of the electric field expansion around the central ion trajectory has also been studied

  7. The dynamics of the spiral structure in galaxies

    International Nuclear Information System (INIS)

    Contopoulos, G.

    1979-01-01

    The basic ideas and current problems of the linear and non-linear theory of spiral structure are reviewed. Some recent work on the response density and possible self-consistent solutions of bars with an Inner Lindblad Resonance are described. (Auth.)

  8. Orientation of spiral galaxies in the local supercluster

    International Nuclear Information System (INIS)

    Jaaniste, J.A.; Saar, E.M.

    1977-01-01

    Two alternative models for the spatial orientation of galaxies - parallelism and perpendicularity of the planes of galaxies with respect to the supergalactic plane - are compared with the observed orientations of spiral galaxies within the volume of the radius of 50 Mpc. The first model does not agree with experimental data whereas the second one-perpendicularity of the planes - describes the above data well

  9. The Neutrons for Science Facility at SPIRAL-2

    Czech Academy of Sciences Publication Activity Database

    Ledoux, X.; Avrigeanu, M.; Avrigeanu, V.; Bém, Pavel; Fischer, U.; Majerle, Mitja; Mrázek, Jaromír; Negoita, F.; Novák, Jan; Simakov, S. P.; Šimečková, Eva

    2014-01-01

    Roč. 119, MAY (2014), s. 353-356 ISSN 0090-3752 Institutional support: RVO:61389005 Keywords : SPIRAL-2 * Neutron For Science * time-of-flight Subject RIV: BG - Nuclear , Atomic and Molecular Physics, Colliders Impact factor: 4.571, year: 2014

  10. A SEARCH FOR SPIRAL GALAXIES WITH EXTENDED HI DISKS

    NARCIS (Netherlands)

    BROEILS, AH; VANWOERDEN, H

    1994-01-01

    We present short 21-cm line observations of about 50 spiral galaxies, made with the Westerbork Synthesis Radio Telescope. They form the first stage of a two-stage project to study the relation between the shape of extended rotation curves and galaxy properties, such as luminosity and morphological

  11. The present-day galaxy population in spiral galaxies

    NARCIS (Netherlands)

    Peletier, Reynier; Antonelli, LA; Limongi, M; Menci, N; Tornambe, A; Brocato, E; Raimondo, G

    2009-01-01

    Although there are many more stellar population studies of elliptical and lenticular galaxies, studies of spiral galaxies are catching up, due to higher signal to noise data on one hand, and better analysis methods on the other. Here I start by discussing some modern methods of analyzing integrated

  12. Stability of spiral welded tubes in Quay Walls

    NARCIS (Netherlands)

    Gresnigt, A.M.; van Es, S.H.J.

    2013-01-01

    A European research project (RFCS) has started to provide economic and safe guidance for the design of spirally welded tubes in combined walls. The main motivation for this project called COMBITUBE is that the current Eurocode 3 regulations for tubes in quay walls lead to uneconomic designs, because

  13. Measurement of lung volumes : usefulness of spiral CT

    International Nuclear Information System (INIS)

    Kang, Ho Yeong; Kwak, Byung Kook; Lee, Sang Yoon; Kim, Soo Ran; Lee, Shin Hyung; Lee, Chang Joon; Park, In Won

    1996-01-01

    To evaluate the usefulness of spiral CT in the measurement of lung volumes. Fifteen healthy volunteers were studied by both spirometer and spiral CT at full inspiration and expiration in order to correlated their results, including total lung capacity (TLC), vital capacity (VC) and residual volume (RV). 3-D images were reconstructed from spiral CT, and we measured lung volumes at a corresponding CT window range ; their volumes were compared with the pulmonary function test (paired t-test). The window range corresponding to TLC was from -1000HU to -150HU (p=0.279, r=0.986), and for VC from -910HU to -800HU (p=0.366, r=0.954) in full-inspiratory CT. The optimal window range for RV in full-expiratory CT was from -1000HU to -450HU (p=0.757, r=0.777), and TLC-VC in full-inspiratory CT was also calculated (p=0.843, r=0.847). Spiral CT at full inspiration can used to lung volumes such as TLC, VC and RV

  14. Kinematic properties of supergiants in the Perseus spiral arm

    Energy Technology Data Exchange (ETDEWEB)

    Gerasimenko, T P [Ural' skij Gosudarstvennyj Univ., Sverdlovsk (USSR)

    1963-05-01

    Large-scale inhomogeneity of the velocity field in the Perseus spiral arm region is found on the basis of the analysis of spatial motions of supergiants. The inhomogeneity seems to be connected with both presence of large groups of young stars and systematic motions in the arm predicted by the density wave theory. Proper motions of 78 stars are presented.

  15. Long term complications of the intraprostatic spiral. Case report

    DEFF Research Database (Denmark)

    Krogh, J

    1992-01-01

    A 76-year-old man had an intraprostatic spiral inserted to relieve bladder outlet obstruction that was caused by benign prostatic hypertrophy. After 30 months numerous complications had arisen including severe encrustations, urethral stricture, and sclerosis of the bladder neck. Regular replaceme...

  16. A combined optical, SEM and STM study of growth spirals

    Indian Academy of Sciences (India)

    Some novel results of a combined sequential study of growth spirals on the basal surface of the richly polytypic CdI2 crystals by optical microscopy, scanning electron microscopy (SEM) and scanning tunneling microscopy (STM) are presented and discussed. In confirmation of the known structural data, the STM pictures ...

  17. Spiral density waves and vertical circulation in protoplanetary discs

    Science.gov (United States)

    Riols, A.; Latter, H.

    2018-06-01

    Spiral density waves dominate several facets of accretion disc dynamics - planet-disc interactions and gravitational instability (GI) most prominently. Though they have been examined thoroughly in two-dimensional simulations, their vertical structures in the non-linear regime are somewhat unexplored. This neglect is unwarranted given that any strong vertical motions associated with these waves could profoundly impact dust dynamics, dust sedimentation, planet formation, and the emissivity of the disc surface. In this paper, we combine linear calculations and shearing box simulations in order to investigate the vertical structure of spiral waves for various polytropic stratifications and wave amplitudes. For sub-adiabatic profiles, we find that spiral waves develop a pair of counter-rotating poloidal rolls. Particularly strong in the non-linear regime, these vortical structures issue from the baroclinicity supported by the background vertical entropy gradient. They are also intimately connected to the disc's g modes which appear to interact non-linearly with the density waves. Furthermore, we demonstrate that the poloidal rolls are ubiquitous in gravitoturbulence, emerging in the vicinity of GI spiral wakes, and potentially transporting grains off the disc mid-plane. Other than hindering sedimentation and planet formation, this phenomena may bear on observations of the disc's scattered infrared luminosity. The vortical features could also impact on the turbulent dynamo operating in young protoplanetary discs subject to GI, or possibly even galactic discs.

  18. A Spiral And Discipline-Oriented Curriculum In Medical Imaging

    DEFF Research Database (Denmark)

    Wilhjelm, Jens E.; Hanson, Lars G.; Henneberg, Kaj-Åge

    2011-01-01

    This contribution describes and evaluates an experimental combination of a spiral and discipline-oriented curriculum implemented in the bachelor’s and master’s program in Medicine and Technology. The implementation in the master’s program is in the form of a study line in Medical Imaging and Radi......This contribution describes and evaluates an experimental combination of a spiral and discipline-oriented curriculum implemented in the bachelor’s and master’s program in Medicine and Technology. The implementation in the master’s program is in the form of a study line in Medical Imaging...... and Radiation Physics containing three disciplines: Imaging modalities, Radiation therapy and Image processing. The two imaging courses in the bachelor’s program and the first imaging course in the master’s program follow a spiral curriculum in which most disciplines are encountered in all courses......, but in a gradually more advanced manner. The remaining courses in the master’s program follow a discipline-oriented curriculum. From a practical point of view, the spiral course portfolio works well in an undergraduate environment, where the courses involved are to be taken by all students and in the order planned...

  19. Structure analysis of edge-on spiral galaxies

    NARCIS (Netherlands)

    deGrijs, R; vanderKruit, PC

    The stellar distribution of a small sample of edge-on spiral galaxies is examined in B, V, R, and I by fitting model distributions to the light profiles, both perpendicular to the galaxy planes and along the major axes. We have developed a method to compare the fits for the models obtained for

  20. A generating mechanism of spiral structure in barred galaxies

    International Nuclear Information System (INIS)

    Thielheim, K.O.; Wolff, H.

    1982-01-01

    The time-dependent response of non-interacting stars to growing oval distortions in disc galaxies is calculated by following their motion numerically and Fourier-analysing their positions. Long-lived spiral density waves are found for fast-growing perturbations as well as in cases in which the perturbation evolves only slowly, compared with a characteristic internal rotation period of the disc. This mechanism of driving a spiral structure in non-self-gravitating stellar discs provides an explanation for the long-lived global spiral patterns, observed in N-body experiments showing an evolving central bar, that is not based on the self-gravitation in the disc. In conjunction with the theory of Lynden-Bell according to which angular momentum transfer in the disc leads to a slow increase of the oval distortion, this effect provides a general mechanism for the generation of spiral structure in barred galaxies. In addition to stellar discs with velocity dispersion, cold discs, with the stars initially in circular motion, which bear great similarity to gaseous discs, are investigated. The linear epicyclic approximation is used to develop an analytical description of the generating mechanism. (author)

  1. Fostering Transfer of Study Strategies: A Spiral Model.

    Science.gov (United States)

    Davis, Denise M.; Clery, Carolsue

    1994-01-01

    Describes the design and implementation of a Spiral Model for the introduction and repeated practice of study strategies, based on Taba's model for social studies. In a college reading and studies strategies course, key strategies were introduced early and used through several sets of humanities and social and physical sciences readings. (Contains…

  2. Spontaneous generation of spiral waves by a hydrodynamic instability

    NARCIS (Netherlands)

    Habibi, M.; Møller, P.C.F.; Ribe, N.M.; Bonn, D.

    2008-01-01

    The coiling of a thin filament of viscous fluid falling onto a surface is a common and easily reproducible hydrodynamic instability. Here we report for the first time that this instability can generate regular spiral patterns, in which air bubbles are trapped in the coil and then advected

  3. Opaque spiral disks - Some empirical facts and consequences

    NARCIS (Netherlands)

    Valentijn, Edwin A.

    1990-01-01

    Results for the Sb and Sc galaxies, as obtained from the analysis of the optical ESO-LV data, are reviewed, and the implied constraints for the properties of the absorbing components in spiral disks are discussed. An alternative interpretation of flat rotation curves and a revised extinction model

  4. Spiral intensity patterns in the internally pumped optical parametric oscillator

    DEFF Research Database (Denmark)

    Lodahl, Peter; Bache, Morten; Saffman, Mark

    2001-01-01

    We describe a nonlinear optical system that supports spiral pattern solutions in the field intensity. This new spatial structure is found to bifurcate above a secondary instability in the internally pumped optical parametric oscillator. The analytical predictions of threshold and spatial scale...

  5. Exact cone beam CT with a spiral scan

    International Nuclear Information System (INIS)

    Tam, K.C.; Samarasekera, S.; Sauer, F.

    1998-01-01

    A method is developed which makes it possible to scan and reconstruct an object with cone beam x-rays in a spiral scan path with area detectors much shorter than the length of the object. The method is mathematically exact. If only a region of interest of the object is to be imaged, a top circle scan at the top level of the region of interest and a bottom circle scan at the bottom level of the region of interest are added. The height of the detector is required to cover only the distance between adjacent turns in the spiral projected at the detector. To reconstruct the object, the Radon transform for each plane intersecting the object is computed from the totality of the cone beam data. This is achieved by suitably combining the cone beam data taken at different source positions on the scan path; the angular range of the cone beam data required at each source position can be determined easily with a mask which is the spiral scan path projected on the detector from the current source position. The spiral scan algorithm has been successfully validated with simulated cone beam data. (author)

  6. Advanced Manufacture of Spiral Bevel and Hypoid Gears

    Directory of Open Access Journals (Sweden)

    Vilmos Simon

    2016-11-01

    Full Text Available In this study, an advanced method for the manufacture of spiral bevel and hypoid gears on CNC hypoid generators is proposed. The optmal head-cutter geometry and machine tool settings are determined to introduce the optimal tooth surface modifications into the teeth of spiral bevel and hypoid gears. The aim of these tooth surface modifications is to simultaneously reduce the tooth contact pressure and the transmission errors, to maximize the EHD load carrying capacity of the oil film, and to minimize power losses in the oil film. The proposed advanced method for the manufacture of spiral bevel and hypoid gears is based on machine tool setting variation on the cradle-type generator conducted by optimal polynomial functions and on the use of a CNC hypoid generator. An algorithm is developed for the execution of motions on the CNC hypoid generator using the optimal relations on the cradle-type machine. Effectiveness of the method was demonstrated by using spiral bevel and hypoid gear examples. Significant improvements in the operating characteristics of the gear pairs are achieved.

  7. SPIRAL (Sandia's Program for Information Retrieval and Listing)

    Science.gov (United States)

    West, Leslie E.

    The general scope of SPIRAL is storage of free-flowing text information into a machine-readable library and recall of any portions of this stored information that are relevant to an inquiry. The major objectives in the design of the system were (1) to make it easy to use by persons unfamiliar with computer systems; and (2) to make it efficient, in…

  8. Flux flow and cleaning enhancement in a spiral membrane element ...

    African Journals Online (AJOL)

    The effect of backpulsing, into the permeate space of a 2.5 inch spiral wrap membrane, on the prevention of fouling (flux enhancement) was investigated experimentally. These experiments were performed using a 500 mg∙ℓ-1 dextrin solution and a 100 000 MCWO polypropylene membrane, with a feed pressure of 100 kPa ...

  9. Spiral swimming behavior due to cranial and vertebral lesions associated with Cytophaga psychrophila infections in salmonid fishes

    Science.gov (United States)

    Kent, M.L.; Groff, J.M.; Morrison, J.K.; Yasutake, W.T.; Holt, R.A.

    1989-01-01

    C. psychrophila infections of the cranium and anterior vertebrae in salmonid fishes were associated with ataxia, spiral swimming along the axis of the fish, and death. The syndrome was observed in 2-10% of underyearling coho salmon Oncorhynchus kisutch, rainbow troutSalmo gairdneri, and steelhead trout S. gairdneri at several private, state, and federal hatcheries in Washington and Oregon, USA, between 1963 and 1987. Affected fish did not recover and ultimately died. Histological examination consistently revealed subacute to chronic periostitis, osteitis, meningitis, and ganglioneuritis. Inflammation and periosteal proliferation of the anterior vertebrae at the junction of the vertebral column with the cranium with extension into the cranial case was a consistent feature. The adjacent nervous tissue, particularly the medulla, was often compressed by the proliferative lesion, and this may have caused the ataxia. Though bacteria were seldom observed in these lesions. C. psychrophilawas isolated in culture from the cranial cavity of all affected fish that were tested. Epidemiological observations suggested that this bacterium is the causative agent because the spiral swimming behaviour and lesions were observed only in populations that had recovered from acute C. psychrophila infections.

  10. Center column design of the PLT

    International Nuclear Information System (INIS)

    Citrolo, J.; Frankenberg, J.

    1975-01-01

    The center column of the PLT machine is a secondary support member for the toroidal field coils. Its purpose is to decrease the bending moment at the nose of the coils. The center column design was to have been a stainless steel casting with the toroidal field coils grouped around the casting at installation, trapping it in place. However, the castings developed cracks during fabrication and were unsuitable for use. Installation of the coils proceeded without the center column. It then became necessary to redesign a center column which would be capable of installation with the toroidal field coils in place. The final design consists of three A-286 forgings. This paper discusses the final center column design and the influence that new knowledge, obtained during the power tests, had on the new design

  11. Evolution of Gas Across Spiral Arms in the Whirlpool Galaxy

    Science.gov (United States)

    Louie, Melissa Nicole

    To investigate the dynamic evolution of gas across spiral arms, we conducted a detailed study of the gas and star formation along the spiral arms in the Whirlpool Galaxy, M51. This nearby, face-on spiral galaxy provides a unique laboratory to study the relationship between gas dynamics and star formation. The textbook picture of interstellar medium (ISM) evolution is rapidly changing. Molecular gas was once believed to form along spiral arms from the diffuse atomic gas in the inter-arm regions. Star formation occurs within giant molecular clouds during spiral arm passage. Lastly, the molecular gas is photo-dissociated back into atomic gas by massive stars on the downstream side of the spiral arm. Recent evidence, however, is revealing a new picture of the interstellar medium and the process of star formation. We seek development of a new picture by studying the development and evolution of molecular gas and the role of large scale galactic dynamics in organizing the interstellar medium. This thesis begins by presenting work measuring the geometrical offsets between interstellar gas and recent star formation. Interstellar gas is traced by atomic hydrogen and carbon monoxide (CO). Star formation is traced by ionized hydrogen recombination lines and infrared emission from dust warmed by young bright stars. Measuring these offsets can help determine the underlying large scale galactic dynamics. Along the spiral arms in M51, offsets between CO and the star formation tracers suggest that gas is flowing through the spiral arms, but the offsets do not show the expected signature of a single pattern speed and imply a more complicated pattern. This thesis also examines the intermediate stages of gas evolution, by studying a denser component of the ISM closer to which stars will form. Only a small percent of the bulk molecular gas will become dense enough to form stars. HCN and HCO+ probe densities ˜104 cm-3, where as the bulk gas is 500 cm-3. This thesis looks at HCN and

  12. Model for Simulating a Spiral Software-Development Process

    Science.gov (United States)

    Mizell, Carolyn; Curley, Charles; Nayak, Umanath

    2010-01-01

    A discrete-event simulation model, and a computer program that implements the model, have been developed as means of analyzing a spiral software-development process. This model can be tailored to specific development environments for use by software project managers in making quantitative cases for deciding among different software-development processes, courses of action, and cost estimates. A spiral process can be contrasted with a waterfall process, which is a traditional process that consists of a sequence of activities that include analysis of requirements, design, coding, testing, and support. A spiral process is an iterative process that can be regarded as a repeating modified waterfall process. Each iteration includes assessment of risk, analysis of requirements, design, coding, testing, delivery, and evaluation. A key difference between a spiral and a waterfall process is that a spiral process can accommodate changes in requirements at each iteration, whereas in a waterfall process, requirements are considered to be fixed from the beginning and, therefore, a waterfall process is not flexible enough for some projects, especially those in which requirements are not known at the beginning or may change during development. For a given project, a spiral process may cost more and take more time than does a waterfall process, but may better satisfy a customer's expectations and needs. Models for simulating various waterfall processes have been developed previously, but until now, there have been no models for simulating spiral processes. The present spiral-process-simulating model and the software that implements it were developed by extending a discrete-event simulation process model of the IEEE 12207 Software Development Process, which was built using commercially available software known as the Process Analysis Tradeoff Tool (PATT). Typical inputs to PATT models include industry-average values of product size (expressed as number of lines of code

  13. Endodontic management of mandibular third molar with three mesial roots using spiral computed tomography scan as a diagnostic aid: a case report.

    Science.gov (United States)

    Tomar, Deepak; Dhingra, Anil; Tomer, Anil; Sharma, Shalini; Sharma, Vivek; Miglani, Anjali

    2013-05-01

    Aberrant root canal anatomy is diagnostically and clinically challenging for clinicians. The most common root canal configuration of human molars is 2 roots and 3 canals, but various combinations may still exist. Third molars are known to have the most unusual anatomy among human teeth. Restorative, prosthetic, and orthodontic considerations often require endodontic treatment of third molars in order for them to be retained as functional components of the dental arch. The present case report demonstrates unusual root canal morphology of the mandibular third molar. Roentgenographic examination, which included spiral CT scan, revealed 3 separate mesial roots in tooth #48 with 3 independent canals and 3 canal orifices, indicating an endodontic rarity. The present case report puts impetus on exploration of additional canals using advanced diagnostic aids, such as spiral computed tomography, which can have a huge impact on the successful outcome of endodontic therapy. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Admittance Scanning for Whole Column Detection.

    Science.gov (United States)

    Stamos, Brian N; Dasgupta, Purnendu K; Ohira, Shin-Ichi

    2017-07-05

    Whole column detection (WCD) is as old as chromatography itself. WCD requires an ability to interrogate column contents from the outside. Other than the obvious case of optical detection through a transparent column, admittance (often termed contactless conductance) measurements can also sense changes in the column contents (especially ionic content) from the outside without galvanic contact with the solution. We propose here electromechanically scanned admittance imaging and apply this to open tubular (OT) chromatography. The detector scans across the column; the length resolution depends on the scanning velocity and the data acquisition frequency, ultimately limited by the physical step resolution (40 μm in the present setup). Precision equal to this step resolution was observed for locating an interface between two immiscible liquids inside a 21 μm capillary. Mechanically, the maximum scanning speed was 100 mm/s, but at 1 kHz sampling rate and a time constant of 25 ms, the highest practical scan speed (no peak distortion) was 28 mm/s. At scanning speeds of 0, 4, and 28 mm/s, the S/N for 180 pL (zone length of 1.9 mm in a 11 μm i.d. column) of 500 μM KCl injected into water was 6450, 3850, and 1500, respectively. To facilitate constant and reproducible contact with the column regardless of minor variations in outer diameter, a double quadrupole electrode system was developed. Columns of significant length (>1 m) can be readily scanned. We demonstrate its applicability with both OT and commercial packed columns and explore uniformity of retention along a column, increasing S/N by stopped-flow repeat scans, etc. as unique applications.

  15. Dividing wall column: Improving thermal efficiency, energy savings and economic performance

    International Nuclear Information System (INIS)

    Aurangzeb, Md; Jana, Amiya K.

    2016-01-01

    Highlights: • A rigorous model is developed for a dividing wall column. • Heat transfer model for metal wall is proposed. • Performance improvement is quantified for a ternary system. • Thermal efficiency, energy savings and cost are three used indices. - Abstract: This work aims at investigating the performance improvement of a dividing wall column (DWC) for the separation of a ternary system. It is true that for fractionating a ternary mixture, at least a sequence of two conventional distillation columns is required. To improve energetic and economic potential, and reduce space requirement, two columns are proposed to merge into one shell with a dividing wall. For developing the mathematical model of a distillation column, we consider the effect of heat transfer through the metal wall placed at an intermediated position inside the cylindrical column. The simulated DWC model is verified using the Aspen Plus flowsheet simulator with a wide variety of phase equilibrium models. The superiority of this proposed heat integrated configuration is shown for a ternary hydrocarbon system over a conventional distillation sequence (CDS) in terms of mainly three performance indexes, namely thermal efficiency, energy savings and total annual cost (TAC). It is investigated that the dividing wall distillation scheme can secure a 37.5% energy efficiency, and a 22.6% savings in energy consumption and 23.23% in TAC. The promising performance can also be quantified in terms of a reasonably low payback period of 2.11 years.

  16. A novel spiral reactor for biodiesel production in supercritical ethanol

    International Nuclear Information System (INIS)

    Farobie, Obie; Sasanami, Kazuma; Matsumura, Yukihiko

    2015-01-01

    Highlights: • A novel spiral reactor for biodiesel production in supercritical ethanol was proposed. • The spiral reactor employed in this study successfully recovered heat. • The effects of temperature and time on FAEE yield were investigated. • FAEE yield as high as 0.937 mol/mol was obtained at 350 °C after 30 min. • The second-order kinetic model expressed the experimental yield well. - Abstract: A spiral reactor is proposed as a novel reactor design for biodiesel production under supercritical conditions. Since the spiral reactor serves as a heat exchanger, it offers the advantage of reduced apparatus space compared to conventional supercritical equipment. Experimental investigations were carried out at reaction temperatures of 270–400 °C, pressure of 20 MPa, oil-to-ethanol molar ratio of 1:40, and reaction times of 3–30 min. An FAEE yield of 0.937 mol/mol was obtained in a short reaction time of 30 min at 350 °C and oil-to-ethanol molar ratio of 1:40 under a reactor pressure of 20 MPa. The spiral reactor was not only as effective as conventional reactor in terms of transesterification reactor but also was superior in terms of heat recovery. A second-order kinetic model describing the transesterification of canola oil in supercritical ethanol was proposed, and the reaction was observed to follow Arrhenius behavior. The corresponding reaction rate constants and the activation energies as well as pre-exponential factors were determined

  17. Computerized spiral analysis using the iPad.

    Science.gov (United States)

    Sisti, Jonathan A; Christophe, Brandon; Seville, Audrey Rakovich; Garton, Andrew L A; Gupta, Vivek P; Bandin, Alexander J; Yu, Qiping; Pullman, Seth L

    2017-01-01

    Digital analysis of writing and drawing has become a valuable research and clinical tool for the study of upper limb motor dysfunction in patients with essential tremor, Parkinson's disease, dystonia, and related disorders. We developed a validated method of computerized spiral analysis of hand-drawn Archimedean spirals that provides insight into movement dynamics beyond subjective visual assessment using a Wacom graphics tablet. While the Wacom tablet method provides robust data, more widely available mobile technology platforms exist. We introduce a novel adaptation of the Wacom-based method for the collection of hand-drawn kinematic data using an Apple iPad. This iPad-based system is stand-alone, easy-to-use, can capture drawing data with either a finger or capacitive stylus, is precise, and potentially ubiquitous. The iPad-based system acquires position and time data that is fully compatible with our original spiral analysis program. All of the important indices including degree of severity, speed, presence of tremor, tremor amplitude, tremor frequency, variability of pressure, and tightness are calculated from the digital spiral data, which the application is able to transmit. While the iPad method is limited by current touch screen technology, it does collect data with acceptable congruence compared to the current Wacom-based method while providing the advantages of accessibility and ease of use. The iPad is capable of capturing precise digital spiral data for analysis of motor dysfunction while also providing a convenient, easy-to-use modality in clinics and potentially at home. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Spiral arms and disc stability in the Andromeda galaxy

    Science.gov (United States)

    Tenjes, P.; Tuvikene, T.; Tamm, A.; Kipper, R.; Tempel, E.

    2017-04-01

    Aims: Density waves are often considered as the triggering mechanism of star formation in spiral galaxies. Our aim is to study relations between different star formation tracers (stellar UV and near-IR radiation and emission from H I, CO, and cold dust) in the spiral arms of M 31, to calculate stability conditions in the galaxy disc, and to draw conclusions about possible star formation triggering mechanisms. Methods: We selected fourteen spiral arm segments from the de-projected data maps and compared emission distributions along the cross sections of the segments in different datasets to each other, in order to detect spatial offsets between young stellar populations and the star-forming medium. By using the disc stability condition as a function of perturbation wavelength and distance from the galaxy centre, we calculated the effective disc stability parameters and the least stable wavelengths at different distances. For this we used a mass distribution model of M 31 with four disc components (old and young stellar discs, cold and warm gaseous discs) embedded within the external potential of the bulge, the stellar halo, and the dark matter halo. Each component is considered to have a realistic finite thickness. Results: No systematic offsets between the observed UV and CO/far-IR emission across the spiral segments are detected. The calculated effective stability parameter has a lowest value of Qeff ≃ 1.8 at galactocentric distances of 12-13 kpc. The least stable wavelengths are rather long, with the lowest values starting from ≃ 3 kpc at distances R > 11 kpc. Conclusions: The classical density wave theory is not a realistic explanation for the spiral structure of M 31. Instead, external causes should be considered, such as interactions with massive gas clouds or dwarf companions of M 31.

  19. Comparison of M33 and NGC7793: stochastic models of spiral galaxies modulated by density waves

    International Nuclear Information System (INIS)

    Smith, G.; Elmegreen, B.G.; Elmegreen, D.M.

    1984-01-01

    Two late-type spiral galaxies with similar kinematic and photometric properties but different spiral arm structures, M33 and NGC7793, are compared to model galaxies with stochastic self-propagating star formation. The spontaneous probability, Psub(sp), representing the rate of primary star formation, is modulated by a smooth, density wave-like spiral pattern in the models of M33. When propagating star formation is included, these models show no age gradients in the underlying spiral arms. Models which have no imposed spiral modulation to Psub(sp) resemble the observed structure of NGC7793. (author)

  20. Knowledge Based Product Configuration - a documentatio tool for configuration projects

    DEFF Research Database (Denmark)

    Hvam, Lars; Malis, Martin

    2003-01-01

    . A lot of knowledge isput into these systems and many domain experts are involved. This calls for an effective documentation system in order to structure this knowledge in a way that fits to the systems. Standard configuration systems do not support this kind of documentation. The chapter deals...... with the development of a Lotus Notes application that serves as a knowledge based documentation tool for configuration projects. A prototype has been developed and tested empirically in an industrial case-company. It has proved to be a succes....

  1. Additional Tension Screws Improve Stability in Elastic Stable Intramedullary Nailing: Biomechanical Analysis of a Femur Spiral Fracture Model.

    Science.gov (United States)

    Zachert, Gregor; Rapp, Marion; Eggert, Rebecca; Schulze-Hessing, Maaike; Gros, Nina; Stratmann, Christina; Wendlandt, Robert; Kaiser, Martin M

    2015-08-01

    For pediatric femoral shaft fractures, elastic stable intramedullary nailing (ESIN) is an accepted method of treatment. But problems regarding stability with shortening or axial deviation are well known in complex fracture types and heavier children. Biomechanical in vitro testing was performed to determine whether two modified osteosyntheses with an additional tension screw fixation or screw fixation alone without nails could significantly improve the stability in comparison to classical ESIN. A total of 24 synthetic adolescent-sized femoral bone models (Sawbones, 4th generation; Vashon, Washington, United States) with an identical spiral fracture (length 100 mm) were used. All grafts underwent retrograde fixation with two C-shaped steel nails (2C). Of the 24, 8 osteosyntheses were supported by one additional tension screw (2C1S) and another 8 by two screws (2S) in which the intramedullary nails were removed before testing. Each configuration underwent biomechanical testing in 4-point bending, external rotation (ER) and internal rotation (IR). Furthermore, the modifications were tested in axial physiological 9 degrees position for shifting and dynamic compression as well as dynamic load. Both screw configurations (2C1S and 2S) demonstrated a significantly higher stability in comparison to the 2C configuration in 4-point bending (anterior-posterior, 0.95 Nm/mm [2C] spiral fracture model, the stability of ESIN could be significantly improved by two modifications with additional tension screws. If transferred in clinical practice, these modifications might offer earlier weight bearing and less problems of shortening or axial deviation. Georg Thieme Verlag KG Stuttgart · New York.

  2. The Southwest Configuration for the Next Generation Very Large Array

    Science.gov (United States)

    Irwin Kellermann, Kenneth; Carilli, Chris; Condon, James; Cotton, William; Murphy, Eric Joseph; Nyland, Kristina

    2018-01-01

    We discuss the planned array configuration for the Next Generation Very Large Array (ngVLA). The configuration, termed the "Southwest Array," consists of 214 antennas each 18 m in diameter, distributed over the Southwest United States and Northern Mexico. The antenna locations have been set applying rough real-world constraints, such as road, fiber, and power access. The antenna locations will be fixed, with roughly 50% of the antennas in a "core" of 2 km diameter, located at the site of the JVLA. Another 30% of the antennas will be distributed over the Plains of San Augustin to a diameter of 30 km, possibly along, or near, the current JVLA arms. The remaining 20% of the antennas will be distributed in a rough two-arm spiral pattern to the South and East, out to a maximum distance of 500 km, into Texas, Arizona, and Chihuahua. Years of experience with the VLA up to 50 GHz, plus intensive antenna testing up to 250 GHz for the ALMA prototype antennas, verify the VLA site as having very good observing conditions (opacity, phase stability), up to 115 GHz (ngVLA Memo No. 1). Using a suite of tools implemented in CASA, we have made extensive imaging simulations with this configuration. We find that good imaging performance can be obtained through appropriate weighting of the visibilities, for resolutions ranging from that of the core of the array (1" at 30 GHz), out to the longest baselines (10 mas at 30 GHz), with a loss of roughly a factor of two in sensitivity relative to natural weighting (ngVLA Memo No. 16). The off-set core, located on the northern edge of the long baseline configuration, provides excellent sensitivity even on the longest baselines. We are considering, in addition, a compact configuration of 16 close-packed 6 m antennas to obtain uv-coverage down to baselines ~ 10 m for imaging large scale structure, as well as a configuration including 9 stations distributed to continental scales.

  3. Collapse of tall granular columns in fluid

    Science.gov (United States)

    Kumar, Krishna; Soga, Kenichi; Delenne, Jean-Yves

    2017-06-01

    Avalanches, landslides, and debris flows are geophysical hazards, which involve rapid mass movement of granular solids, water, and air as a multi-phase system. In order to describe the mechanism of immersed granular flows, it is important to consider both the dynamics of the solid phase and the role of the ambient fluid. In the present study, the collapse of a granular column in fluid is studied using 2D LBM - DEM. The flow kinematics are compared with the dry and buoyant granular collapse to understand the influence of hydrodynamic forces and lubrication on the run-out. In the case of tall columns, the amount of material destabilised above the failure plane is larger than that of short columns. Therefore, the surface area of the mobilised mass that interacts with the surrounding fluid in tall columns is significantly higher than the short columns. This increase in the area of soil - fluid interaction results in an increase in the formation of turbulent vortices thereby altering the deposit morphology. It is observed that the vortices result in the formation of heaps that significantly affects the distribution of mass in the flow. In order to understand the behaviour of tall columns, the run-out behaviour of a dense granular column with an initial aspect ratio of 6 is studied. The collapse behaviour is analysed for different slope angles: 0°, 2.5°, 5° and 7.5°.

  4. Field Applications of Gamma Column Scanning Technology

    International Nuclear Information System (INIS)

    Aquino, Denis D.; Mallilin, Janice P.; Nuñez, Ivy Angelica A.; Bulos, Adelina DM.

    2015-01-01

    The Isotope Techniques Section (ITS) under the Nuclear Service Division (NSD) of the Philippine Nuclear Research Institute (PNRI) conducts services, research and development on radioisotope and sealed source application in the industry. This aims to benefit the manufacturing industries such as petroleum, petrochemical, chemical, energy, waste, column treatment plant, etc. through on line inspection and troubleshooting of a process vessel, column or pipe that could optimize the process operation and increase production efficiency. One of the most common sealed source techniques for industrial applications is the gamma column scanning technology. Gamma column scanning technology is an established technique for inspection, analysis and diagnosis of industrial columns for process optimization, solving operational malfunctions and management of resources. It is a convenient non-intrusive, cost effective and cost-efficient technique to examine inner details of an industrial process vessel such as a distillation column while it is in operation. The Philippine Nuclear Research Institute (PNRI) recognize the importance and benefits of this technology and has implemented activities to make gamma column scanning locally available to benefit the Philippine industries. Continuous effort for capacity building is being pursued thru the implementation of in-house and on-the-job training abroad and upgrading of equipment. (author)

  5. Spiral Wave in Small-World Networks of Hodgkin-Huxley Neurons

    International Nuclear Information System (INIS)

    Ma Jun; Zhang Cairong; Yang Lijian; Wu Ying

    2010-01-01

    The effect of small-world connection and noise on the formation and transition of spiral wave in the networks of Hodgkin-Huxley neurons are investigated in detail. Some interesting results are found in our numerical studies. i) The quiescent neurons are activated to propagate electric signal to others by generating and developing spiral wave from spiral seed in small area. ii) A statistical factor is defined to describe the collective properties and phase transition induced by the topology of networks and noise. iii) Stable rotating spiral wave can be generated and keeps robust when the rewiring probability is below certain threshold, otherwise, spiral wave can not be developed from the spiral seed and spiral wave breakup occurs for a stable rotating spiral wave. iv) Gaussian white noise is introduced on the membrane of neurons to study the noise-induced phase transition on spiral wave in small-world networks of neurons. It is confirmed that Gaussian white noise plays active role in supporting and developing spiral wave in the networks of neurons, and appearance of smaller factor of synchronization indicates high possibility to induce spiral wave. (interdisciplinary physics and related areas of science and technology)

  6. MEASUREMENT OF GALACTIC LOGARITHMIC SPIRAL ARM PITCH ANGLE USING TWO-DIMENSIONAL FAST FOURIER TRANSFORM DECOMPOSITION

    International Nuclear Information System (INIS)

    Davis, Benjamin L.; Berrier, Joel C.; Shields, Douglas W.; Kennefick, Julia; Kennefick, Daniel; Seigar, Marc S.; Lacy, Claud H. S.; Puerari, Ivânio

    2012-01-01

    A logarithmic spiral is a prominent feature appearing in a majority of observed galaxies. This feature has long been associated with the traditional Hubble classification scheme, but historical quotes of pitch angle of spiral galaxies have been almost exclusively qualitative. We have developed a methodology, utilizing two-dimensional fast Fourier transformations of images of spiral galaxies, in order to isolate and measure the pitch angles of their spiral arms. Our technique provides a quantitative way to measure this morphological feature. This will allow comparison of spiral galaxy pitch angle to other galactic parameters and test spiral arm genesis theories. In this work, we detail our image processing and analysis of spiral galaxy images and discuss the robustness of our analysis techniques.

  7. Measurement of Galactic Logarithmic Spiral Arm Pitch Angle Using Two-dimensional Fast Fourier Transform Decomposition

    Science.gov (United States)

    Davis, Benjamin L.; Berrier, Joel C.; Shields, Douglas W.; Kennefick, Julia; Kennefick, Daniel; Seigar, Marc S.; Lacy, Claud H. S.; Puerari, Ivânio

    2012-04-01

    A logarithmic spiral is a prominent feature appearing in a majority of observed galaxies. This feature has long been associated with the traditional Hubble classification scheme, but historical quotes of pitch angle of spiral galaxies have been almost exclusively qualitative. We have developed a methodology, utilizing two-dimensional fast Fourier transformations of images of spiral galaxies, in order to isolate and measure the pitch angles of their spiral arms. Our technique provides a quantitative way to measure this morphological feature. This will allow comparison of spiral galaxy pitch angle to other galactic parameters and test spiral arm genesis theories. In this work, we detail our image processing and analysis of spiral galaxy images and discuss the robustness of our analysis techniques.

  8. MEASUREMENT OF GALACTIC LOGARITHMIC SPIRAL ARM PITCH ANGLE USING TWO-DIMENSIONAL FAST FOURIER TRANSFORM DECOMPOSITION

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Benjamin L.; Berrier, Joel C.; Shields, Douglas W.; Kennefick, Julia; Kennefick, Daniel; Seigar, Marc S.; Lacy, Claud H. S. [Arkansas Center for Space and Planetary Sciences, 202 Field House, University of Arkansas, Fayetteville, AR 72701 (United States); Puerari, Ivanio [Instituto Nacional de Astrofisica, Optica y Electronica, Calle Luis Enrique Erro 1, 72840 Santa Maria Tonantzintla, Puebla (Mexico)

    2012-04-01

    A logarithmic spiral is a prominent feature appearing in a majority of observed galaxies. This feature has long been associated with the traditional Hubble classification scheme, but historical quotes of pitch angle of spiral galaxies have been almost exclusively qualitative. We have developed a methodology, utilizing two-dimensional fast Fourier transformations of images of spiral galaxies, in order to isolate and measure the pitch angles of their spiral arms. Our technique provides a quantitative way to measure this morphological feature. This will allow comparison of spiral galaxy pitch angle to other galactic parameters and test spiral arm genesis theories. In this work, we detail our image processing and analysis of spiral galaxy images and discuss the robustness of our analysis techniques.

  9. On the possibility of simultaneous spiral and superfluid ordering in a Fermi-liquid

    International Nuclear Information System (INIS)

    Peletminskij, S.V.; Yatsenko, A.A.; Shulga, S.N.

    2004-01-01

    The paper concerns a particular possibility of ordering for Fermi systems - a superfluid spiral ordering, at which in addition to the phase invariance breakdown there occurs a violence of the translational and the spin rotation invariance. A general approach of studying of the superfluid spiral ordering is formulated on the basis of the Fermi liquid method. For a monocomponent Fermi system self-consistency equations for four order parameters and the temperature of simultaneous transition to spiral and superfluid states are obtained. The system of equations is studied under the assumption of two order parameters being distinct from zero. The spiral parameter dependences of the transition temperature and the energy gap in the spectrum of elementary fermion excitations are calculated. An interval of the spiral parameter values within which the superfluid spiral ordering can exist is determined. The spin correlation function at the spiral ordering is studied

  10. Floating venous thrombi: diagnosis with spiral-CT-venography; Diagnose flottierender venoeser Thromben mittels Phlebo-Spiral-CT

    Energy Technology Data Exchange (ETDEWEB)

    Gartenschlaeger, M. [Mainz Univ. (Germany). Klinik fuer Radiologie; Klose, K.J. [Univ. Marburg, Medizinisches Zentrum fuer Innere Medizin, Abt. Poliklinik (Germany); Schmidt, J.A. [Univ. Marburg, Medizinisches Zentrum fuer Radiologie, Abt. fuer Strahlendiagnostik (Germany)

    1996-05-01

    Local application of contrast agent into an ipsilateral dorsal foot vein and spiral CT were used to examine 16 consecutive cases with deep venous thrombosis proven at conventional venography; in addition, colour Doppler flow imaging was performed. At conventional venography, 8/16 thrombi appeared to be floating and the remaining 8/16 were adherent to the vessel wall. Spiral-CT showed 15/16 thrombi to be adherent to the vessel wall; the floating thrombus correlated with findings in conventional venography. At colour Doppler flow imaging 3/16 thrombi were considered floating, one of them was discordant to conventional venography. The comparison of conventional venography to spiral-CT demonstrates complete agreement for adherence to vessel wall seen in conventional venography (p=1,0) and significant discordance in cases with free-floating appearance in conventional venography. Adherence of thrombi to the wall of the vessel at conventional venography is in agreement with computed tomography. Conventional venography probably overestimates the prevalence of free floating thrombi. (orig./MG) [Deutsch] Mittels lokaler Kontrastmittelapplikation in eine ipsilaterale Fussrueckenvene und Spiral-CT wurden 16 konsekutive Faelle konventionell phlebographisch gesicherter Phlebothrombose untersucht, zusaetzlich wurde die farbkodierte Doppler-Ultraschalluntersuchung durchgefuehrt. In der konventionellen Phlebographie waren 8/16 Thromben flottierend, die uebrigen 8/16 wandadhaerent. In der Spiral-CT zeigten sich Wandadhaerenzen in 15/16 Faellen; der nachgewiesene flottierende Thrombus stimmte mit der konventionellen Phlebographie ueberein. Im farbkodierten Doppler-Ultraschall erschienen die Thromben in 3/16 Faellen flottierend, darunter ein von der konventionellen Phlebographie abweichender Befund. Der Vergleich von konventioneller und CT-Phlebographie ergab eine komplette Uebereinstimmung fuer konventionell phlebographisch nachgewiesene Wandadhaerenz und eine signifikante Abweichung

  11. Separation of substances in rotating coiled columns: from trace elements to microparticles

    International Nuclear Information System (INIS)

    Spivakov, B.Ya.; Maryutina, T.A.; Fedotov, P.S.; Ignatova, S.N.; Katasonova, O.N.; Damen, I.; Vennrikh, R.

    2002-01-01

    The wide possibilities of using the rotating spiral columns by analysis of the material, differing in their chemical and phase composition, in particular by determining the rare earth elements impurities (REE) in the highly pure calcium chloride are described. The analysis is based on the REE group extraction through the liquid chromatography method with the free immovable phase and application of the octyl(phenyl)-N,N-diisobutyl-carbamoylmethylphosphineoxide in the chloroform with their subsequent determination through the method of the mass spectroscopy with the inductively bound plasma. The limits of the REE determination for this methodology are at the ng/g level; the values of the relative standard deviation do not exceed 15 - 20 % [ru

  12. Distance and total column density to the periodic radio star LSI + 61 deg 303

    International Nuclear Information System (INIS)

    Frail, D.A.; Hjellming, R.M.

    1991-01-01

    New observations toward the periodic radio star LSI + 61 deg 303 in the lines of H I at 21 cm and CO-18 at 2.7 mm are reported. Using the kinematic method, H I observations are interpreted in terms of the two-armed spiral shock model of Roberts (1972) to derive a distance to LSI + 61 deg 303 of 2.0 + or - 0.2 kpc. The results clearly show the presence of the Perseus arm shock and locate LSI + 61 deg 303 between this shock and the more distant postshock gas. In addition, by using the H I and CO-18 data, the total neutral and molecular gas column density is derived along the line of sight toward LSI + 61 deg 303. 32 refs

  13. Moderator Configuration Options for ESS

    DEFF Research Database (Denmark)

    Zanini, L.; Batkov, K.; Klinkby, Esben Bryndt

    2016-01-01

    The current, still evolving status of the design and the optimization work for the moderator configuration for the European Spallation Source is described. The moderator design has been strongly driven by the low-dimensional moderator concept recently proposed for use in spallation neutron sources...... or reactors. Quasi-two dimensional, disc- or tube-shaped moderators,can provide strong brightness increase (factor of 3 or more) with respect to volume para-H2moderators, which constitute the reference, state-of-the-art technology for high-intensity coupled moderators. In the design process other, more...... conventional, principles were also considered,such as the importance of moderator positioning, of the premoderator, and beam extraction considerations. Different design and configuration options are evaluated and compared with the reference volume moderator configuration described in the ESS Technical Design...

  14. Development of Simulator Configuration Tool

    International Nuclear Information System (INIS)

    Nedrelid, Olav; Pettersen, Geir

    1996-01-01

    The main objective of the development of a Simulator Configuration Tool (SCT) is to achieve faster and more efficient production of dynamic simulators. Through application of versatile graphical interfaces, the simulator builder should be able to configure different types of simulators including full-scope process simulators. The SCT should be able to serve different simulator environments. The configuration tool communicates with simulator execution environments through a TCP/IP-based interface, Communication with a Model Server System developed at Institutt for energiteknikk has been established and used as test case. The system consists of OSF/Motif dialogues for operations requiring textual input, list selections etc., and uses the Picasso-3 User Interface Management System to handle presentation of static and dynamic graphical information. (author)

  15. BAYESIAN IMAGE RESTORATION, USING CONFIGURATIONS

    Directory of Open Access Journals (Sweden)

    Thordis Linda Thorarinsdottir

    2011-05-01

    Full Text Available In this paper, we develop a Bayesian procedure for removing noise from images that can be viewed as noisy realisations of random sets in the plane. The procedure utilises recent advances in configuration theory for noise free random sets, where the probabilities of observing the different boundary configurations are expressed in terms of the mean normal measure of the random set. These probabilities are used as prior probabilities in a Bayesian image restoration approach. Estimation of the remaining parameters in the model is outlined for salt and pepper noise. The inference in the model is discussed in detail for 3 X 3 and 5 X 5 configurations and examples of the performance of the procedure are given.

  16. Dynamic Effects of Diabatization in Distillation Columns

    DEFF Research Database (Denmark)

    Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens

    2012-01-01

    The dynamic eects of diabatization in distillation columns are investigated in simulation with primary focus on the heat-integrated distillation column (HIDiC). A generic, dynamic, rst-principle model has been formulated, which is exible to describe various diabatic distillation congurations....... Dynamic Relative Gain Array and Singular Value Analysis have been applied in a comparative study of a conventional distillation column and a HIDiC. The study showed increased input-output coupling due to diabatization. Feasible SISO control structures for the HIDiC were also found. Control...

  17. Column-oriented database management systems

    OpenAIRE

    Možina, David

    2013-01-01

    In the following thesis I will present column-oriented database. Among other things, I will answer on a question why there is a need for a column-oriented database. In recent years there have been a lot of attention regarding a column-oriented database, even if the existence of a columnar database management systems dates back in the early seventies of the last century. I will compare both systems for a database management – a colum-oriented database system and a row-oriented database system ...

  18. Projective configurations in projectivegeometrical drawings

    Directory of Open Access Journals (Sweden)

    Ivashchenko Andrey Viktorovich

    2015-05-01

    Full Text Available The article focuses on the optimization of the earlier discussed computer method of obtaining new forms of polyhedra based on projective geometry drawings (trace Diagrams.While working on getting new multifaceted forms by projective geometry methods based on the well-known models of polyhedra on the first stage of the work it is required to calculate the parameters of projective geometry drawings, and then to build them. This is an often used apparatus of analytical geometry. According to it, at first the parameters of the polyhedron (core system of planes are calculated, then we obtain the equation of the plane of the face of the polyhedron, and finally we obtain the equations of lines the next plane faces on the selected curve plane. At each stage of application such a method requires the use of the algorithms of floating point arithmetic, on the one hand, leads to some loss of accuracy of the results and, on the other hand, the large amount of computer time to perform these operations in comparison with integer arithmetic operations.The proposed method is based on the laws existing between the lines that make up the drawing - the known configurations of projective geometry (complete quadrilaterals, configuration of Desargues, Pappus et al..The authors discussed in detail the analysis procedure of projective geometry drawing and the presence of full quadrilaterals, Desargues and Pappus configurations in it.Since the composition of these configurations is invariant with respect to projective change of the original nucleus, knowing them, you can avoid the calculations when solving the equations for finding direct projective geometry drawing analytically, getting them on the basis of belonging to a particular configuration. So you can get a definite advantage in accuracy of the results, and in the cost of computer time. Finding these basic configurations significantly enriches the set of methods and the use of projective geometry drawings.

  19. Instance-specific algorithm configuration

    CERN Document Server

    Malitsky, Yuri

    2014-01-01

    This book presents a modular and expandable technique in the rapidly emerging research area of automatic configuration and selection of the best algorithm for the instance at hand. The author presents the basic model behind ISAC and then details a number of modifications and practical applications. In particular, he addresses automated feature generation, offline algorithm configuration for portfolio generation, algorithm selection, adaptive solvers, online tuning, and parallelization.    The author's related thesis was honorably mentioned (runner-up) for the ACP Dissertation Award in 2014,

  20. The instability of the spiral wave induced by the deformation of elastic excitable media

    International Nuclear Information System (INIS)

    Ma Jun; Jia Ya; Wang Chunni; Li Shirong

    2008-01-01

    There are some similarities between the spiral wave in excitable media and in cardiac tissue. Much evidence shows that the appearance and instability of the spiral wave in cardiac tissue can be linked to one kind of heart disease. There are many models that can be used to investigate the formation and instability of the spiral wave. Cardiac tissue is excitable and elastic, and it is interesting to simulate the transition and instability of the spiral wave induced by media deformation. For simplicity, a class of the modified Fitzhugh-Nagumo (MFHN) model, which can generate a stable rotating spiral wave, meandering spiral wave and turbulence within appropriate parameter regions, will be used to simulate the instability of the spiral wave induced by the periodical deformation of media. In the two-dimensional case, the total acreage of elastic media is supposed to be invariable in the presence of deformation, and the problem is described with L x x L y = N x ΔxN x Δy = L' x L' y = N x Δx'N x Δy'. In our studies, elastic media are decentralized into N x N sites and the space of the adjacent sites is changed to simulate the deformation of elastic media. Based on the nonlinear dynamics theory, the deformation effect on media is simplified and simulated by perturbing the diffusion coefficients D x and D y with different periodical signals, but the perturbed diffusion coefficients are compensatory. The snapshots of our numerical results find that the spiral wave can coexist with the spiral turbulence, instability of the spiral wave and weak deformation of the spiral wave in different conditions. The ratio parameter ε and the frequency of deformation forcing play a deterministic role in inducing instability of the spiral wave. Extensive studies confirm that the instability of the spiral wave can be induced and developed only if an appropriate frequency for deformation is used. We analyze the power spectrum for the time series of the mean activator of four sampled sites