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Sample records for spirally slotted belleville

  1. Spiral Slotted Microstrip Antenna Design for 700 MHz Band Application

    Directory of Open Access Journals (Sweden)

    Ricardo Meneses González

    2016-01-01

    Full Text Available This work describes the design and implementation of spiral slotted microstrip antenna. Recently, just like other countries, in Mexico, terrestrial digital television has been implemented (analogic shutdown; as a consequence, the 700 MHz UFH Band (698–806 MHz has been opened to new telecommunications services, particularly wireless mobile communication. This technological advance represents a radio mobile antenna design challenge because it is necessary to design an antenna whose dimensions must be small enough, which satisfies gain, resonance frequency, and bandwidth requirements and is of low cost.

  2. Belleville rouge, Belleville noir, Belleville rose: The Complex Identity of a Parisian quartier

    Directory of Open Access Journals (Sweden)

    Carolyn Stott

    2015-03-01

    Full Text Available The Parisian quartier of Belleville has long been the subject of scholarly literature and popular culture due to its colourful history and diverse population. Its symbolic boundaries extend beyond the geographical limits imposed by its administrative demarcation. Myths abound as to the extent of its rebellious past, its contemporary image as a melting pot and its prevalence as a décor for the noir genre. In this article a three-tiered categorisation of Belleville is adopted which corresponds to various representations of the suburb in literature, popular culture and from the perspective of its inhabitants. Belleville rouge reflects the quartier’s revolutionary past and the late 20th century struggle associated with its physical metamorphosis. Belleville noir focusses on the quartier’s criminal face, as it is depicted in Parisian film and roman noir and as it exists in reality. Belleville rose highlights the pleasures of the quartier: its cosmopolitan character whose representation verges at times on utopian.    In his Malaussène series (1985-1995, writer and former resident Daniel Pennac portrays Belleville as a unique blend of rouge, noir and rose. This fusion of fairy tale, detective fiction, myth and reality establishes a complex Bellevillois identity distinct from other contemporary representations. The article concludes that it is impossible to associate a single identity with Belleville. The quartier’s contemporary face is inextricably linked to its past, the memory of which is preserved by its inhabitants and by social and literary commentators such as Pennac. In keeping with historian Pierre Nora’s concept of cultural memory, Pennac thus assumes the role of guardian of Belleville’s cultural memory in the face of the quartier’s perpetual evolution.

  3. Design of UWB Planar Monopole Antennas with Etched Spiral Slot on the Patch for Multiple Band-Notched Characteristics

    Directory of Open Access Journals (Sweden)

    Swarup Das

    2015-01-01

    Full Text Available Three types of Ultrawideband (UWB antennas with single, double, and triple notched bands are proposed and investigated for UWB communication applications. The proposed antennas consist of CPW fed monopole with spiral slot etched on the patch. In this paper single, double, and also triple band notches with central frequency of 3.57, 5.12, and 8.21 GHz have been generated by varying the length of a single spiral slot. The proposed antenna is low-profile and of compact size. A stable gain is obtained throughout the operation band except the three notched frequencies. The antennas have omnidirectional and stable radiation patterns across all the relevant bands. Moreover, relatively consistent group delays across the UWB frequencies are noticed for the triple notched band antenna. A prototype of the UWB antenna with triple notched bands is fabricated and the measured results of the antenna are compared with the simulated results.

  4. Stiffness and design for strength of trapezoidal Belleville springs

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard; Pedersen, Pauli

    2011-01-01

    in this paper. Finite element results are compared with analytical predictions and critically analysed in terms of the effect of Poisson ratio, overall stiffness, and stress distribution in the spring. This is done in order to verify the range of validity of design standards. Finite element analysis emerges......Belleville springs or coned disc springs are commonly used in machine design. The geometric dimensions of the spring and the determination of non-linear force–displacement curve are regulated by different standards. However, the theory behind Belleville spring design standards is founded on a study...... published in 1936. Furthermore, the common spring design with cross-sections of uniform thickness poses problems in terms of non-uniformity of stress distribution. In view of this, non-linear three-dimensional finite element analyses of spring designs including uniform or variable thickness are carried out...

  5. Belleville-sur-Loire nuclear facilities. 2009 annual report

    International Nuclear Information System (INIS)

    2010-01-01

    This annual report is established on account of article 21 of the 2006-686 French law from June 13, 2006, relative to the transparency and safety in the nuclear domain. It describes, first, the nuclear facilities of Belleville-sur-Loire, and then the measures taken to ensure their safety (personnel radioprotection, actions implemented for nuclear safety improvement, organisation in crisis situation, external and internal controls, technical assessment of the facilities, administrative procedures carried out in 2009), incidents and accidents registered in 2009, radioactive and chemical effluents released by the facilities in the environment, other pollutions, management of radioactive wastes, and, finally, the actions carried out in the domain of transparency and public information. A glossary and the viewpoint of the Committee of Hygiene, safety and working conditions about the content of the document conclude the report. (J.S.)

  6. A Belleville-spring-based electromagnetic energy harvester

    International Nuclear Information System (INIS)

    Castagnetti, Davide

    2015-01-01

    Energy harvesting from kinetic ambient energy is particularly effective to power autonomous sensors. This work proposes an innovative energy converter based on two counteracting Belleville springs and exploiting their peculiarity, for a height to thickness ratio equal to 1.414, of nearly zero stiffness over a wide deflection range. After analytical and numerical modelling a prototype is developed and experimentally investigated. The sub-optimal geometry of the commercial springs used in the prototype, together with a non-ideal response, makes the operating frequency for the prototype higher than in analytical and numerical predictions. Nevertheless, the harvester exhibits a significantly large bandwidth, together with a high output power, compared to similar solutions in the literature, for all the examined configurations and input excitations. (paper)

  7. A section of a spiral coal chute

    Energy Technology Data Exchange (ETDEWEB)

    Bakhtin, V.N.; Gorodilov, N.N.

    1981-01-01

    A section of a spiral coal chute includes a housing with support brackets. It differs in that to decrease the amount of work necessary for assembly, each support bracket is made with a guide slot and equipped with a pull-out cantilever in the shape of a fork which covers the slot from the lateral sides.

  8. Nuclear safety and radiation protection report of the Belleville-sur-Loire nuclear facilities - 2011

    International Nuclear Information System (INIS)

    2012-01-01

    This safety report was established under the article 21 of the French law no. 2006-686 of June 13, 2006 relative to nuclear safety and information transparency. It presents, first, the facilities of the Belleville-sur-Loire nuclear power plant (INB no. 127 - Belleville 1 and no. 128 - Belleville 2, Belleville-sur-Loire and Sury-pres-Lere - Cher (FR)). Then, the nuclear safety and radiation protection measures taken regarding the facilities are reviewed: nuclear safety definition, radiation protection of intervening parties, safety and radiation protection improvement paths, crisis management, external and internal controls, technical situation of facilities. The incidents and accidents which occurred in 2011, are reported as well as the radioactive and non-radioactive (chemical, thermal) effluents discharge in the environment. Finally, The radioactive materials and wastes generated by the facilities are presented and sorted by type of waste, quantities and type of conditioning. Other environmental impacts (noise, microbial proliferation in cooling towers) are presented with their mitigation measures. Actions in favour of transparency and public information are presented as well. The document concludes with a glossary and a list of recommendations from the Committees for health, safety and working conditions. (J.S.)

  9. Logarithmic Spiral

    Indian Academy of Sciences (India)

    anti-clockwise direction and we get a right-handed spiral. (Figure 2). We know that the derivative of eX is also eX. Various properties of logarithmic spiral depend on this property of eX. Properties of Logarithmic Spiral. 1. The most important property of a logarithmic spiral is that r (i.e. the distance from the origin) increases.

  10. 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

  11. Tiempo de Dios. Tiempo de los Hombres: El Breviario de Belleville

    Directory of Open Access Journals (Sweden)

    Ofelia Manzi

    2012-11-01

    Full Text Available Las imágenes cristianas, herederas de los sistemas narrativos romanos, expresaron visualmente los contenidos escriturarios. Uno de los elementos notables lo constituye la manera de representar la secuencia temporal en sus dos posibles dimensiones: humana y divina. Un recorrido por el arte cristiano tardo antiguo y medieval permite establecer de qué manera se generó una iconografía que permitió visualizar el mensaje que, de acuerdo con la correspondiente exégesis literaria, se quiso privilegiar en momentos históricos diversos. El objetivo de este trabajo es establecer de qué manera la imagen acompaña una concepción del tiempo en su doble dimensión. El Breviario de Belleville (París, siglo XIV ofrece un ejemplo en el que se conjugan ambas concepciones del transcurrir de la vida del hombre en una particular interpretación iconográfica.  

  12. Broadcast Coded Slotted ALOHA

    DEFF Research Database (Denmark)

    Ivanov, Mikhail; Brännström, Frederik; Graell i Amat, Alexandre

    2016-01-01

    We propose an uncoordinated medium access control (MAC) protocol, called all-to-all broadcast coded slotted ALOHA (B-CSA) for reliable all-to-all broadcast with strict latency constraints. In B-CSA, each user acts as both transmitter and receiver in a half-duplex mode. The half-duplex mode gives...

  13. 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....... Directionality is discussed in terms of the organism-in-environment unfolding over time as the unit of developmental analysis. Thinking on this issue has proceeded from the nature–nurture debates, to recognition of the interaction of external and internal processes, to transactions between the organism...

  14. Slotted Photonic Crystal Sensors

    Science.gov (United States)

    Scullion, Mark G.; Krauss, Thomas F.; Di Falco, Andrea

    2013-01-01

    Optical biosensors are increasingly being considered for lab-on-a-chip applications due to their benefits such as small size, biocompatibility, passive behaviour and lack of the need for fluorescent labels. The light guiding mechanisms used by many of them results in poor overlap of the optical field with the target molecules, reducing the maximum sensitivity achievable. This review article presents a new platform for optical biosensors, namely slotted photonic crystals, which provide higher sensitivities due to their ability to confine, spatially and temporally, the optical mode peak within the analyte itself. Loss measurements showed values comparable to standard photonic crystals, confirming their ability to be used in real devices. A novel resonant coupler was designed, simulated, and experimentally tested, and was found to perform better than other solutions within the literature. Combining with cavities, microfluidics and biological functionalization allowed proof-of-principle demonstrations of protein binding to be carried out. Higher sensitivities were observed in smaller structures than possible with most competing devices reported in the literature. This body of work presents slotted photonic crystals as a realistic platform for complete on-chip biosensing; addressing key design, performance and application issues, whilst also opening up exciting new ideas for future study. PMID:23503295

  15. 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

  16. Study of the radiological and chemical quality of sediments and water of the Loire river at the vicinity of the Belleville-sur-Loire CNPE. Study performed on the request of the Belleville-sur-Loire Local Information Commission

    International Nuclear Information System (INIS)

    Rougier, G.; Josset, M.; Bernollin, A.; Barbey, P.; Boilley, D.; Festoc, S.; Dunand, E.

    2017-01-01

    This study reports an assessment of the influence of present and previous releases of the Belleville-sur-Loire nuclear site, as well as of the persistence of other pollutions in the environment. The report first recalls authorised annual levels for liquid and gaseous radioactive releases and for chemical releases. It describes the strategy and method adopted to assess the radiological and chemical influence of the nuclear power plant on the environment: studied area, sampling locations and samples, examined radiological and chemical parameters. It indicates the adopted strategy and comments results obtained for radiological measurements in waters, in sediments, and in aquatic plants. Results are notably discussed in terms of natural and artificial radioactivity. Chemical measurements are then reported in the same way: strategy, measurements and discussion of results obtained in water and in sediments. Additional information on radionuclides and on sampling and analysis methodologies are given in appendix

  17. Slot-Coupled Barbel Antenna

    DEFF Research Database (Denmark)

    Jørgensen, Kasper Lüthje; Jakobsen, Kaj Bjarne

    2016-01-01

    A novel slot-coupled barbel antenna is designed and analyzed. A sensitivity analysis performed in order to improve the bandwidth, while the center frequency is kept constant.......A novel slot-coupled barbel antenna is designed and analyzed. A sensitivity analysis performed in order to improve the bandwidth, while the center frequency is kept constant....

  18. The Spiral of Euroscepticism

    DEFF Research Database (Denmark)

    Galpin, Charlotte; Trenz, Hans-Jörg

    2017-01-01

    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...

  19. Project of Particular intervention plan of the Belleville-sur-Loire NPP. Special provisions of the ORSEC plan

    International Nuclear Information System (INIS)

    2015-01-01

    The Particular intervention plan (PPI in French) is an emergency plan which foresees the measures and means to be implemented to address the potential risks of the presence and operation of a nuclear facility. This plan is implemented and developed by the Prefect in case of nuclear accident (or incident leading to a potential accident), the impact of which extending beyond the facility perimeter. It represents a special section of the organisation plan for civil protection response (ORSEC plan). The PPI foresees the necessary measures and means for crisis management during the first hours following the accident and is triggered by the Department Prefect according to the information provided by the facility operator. Its aim is to protect the populations leaving within 10 km of the facility against a potential radiological hazard. The PPI describes: the facility, the intervention area, the protection measures for the population, the conditions of emergency plan triggering, the crisis organisation, the action forms of the different services, and the post-accident stage. This document is the project of Particular intervention plan for the Belleville-sur-Loire Nuclear Power Plant (Cher, France)

  20. Seawave Slot-Cone Generator

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Margheritini, Lucia; Contestabile, Pasquale

    2009-01-01

    This paper discusses a new type of Wave Energy Converter (WEC) named Seawave Slot-Cone Generator (SSG). The SSG is a WEC of the overtopping type. The structure consists of a number of reservoirs one on the top of each others above the mean water level in which the water of incoming waves is store...

  1. 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)

  2. The Gambling Reducing Slot Machine

    DEFF Research Database (Denmark)

    Callesen, Mette Buhl; Thomsen, Kristine Rømer; Linnet, Jakob

    2007-01-01

    and willingness to continue gambling. The results may have important implications for understanding how to reduce gambling behavior in pathological gamblers.   [1] Griffiths, M. 1999. Gambling Technologies: Prospects for Problem Gambling. Journal of Gambling Studies, vol. 15(3), pp. 265-283.    ......  The Gambling Reducing Slot Machine - Preliminary results Mette Buhl Callesen, Kristine Rømer Thomsen, Jakob Linnet and Arne Møller The PET Centre, Aarhus University Hospital and Centre of Functionally Integrative Neuroscience, Aarhus, Denmark   Slot machines are among the most addictive forms...... of gambling due to their specific structural characteristics. These include a high event frequency (number of games per minute), a high frequency of small wins and near misses, and auditory as well as visual feedback that reinforce extended gambling behavior [1].   This study focused on gambling behavior...

  3. 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

  4. Vertically Polarized Omnidirectional Printed Slot Loop Antenna

    DEFF Research Database (Denmark)

    Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren H.; Thaysen, Jesper

    2015-01-01

    A novel vertically polarized omnidirectional printed slot loop antenna has been designed, simulated, fabricated and measured. The slot loop works as a magnetic loop. The loop is loaded with inductors to insure uniform and in-phase fields in the slot in order to obtain an omnidirectional radiation...... pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due to the polarization.......A novel vertically polarized omnidirectional printed slot loop antenna has been designed, simulated, fabricated and measured. The slot loop works as a magnetic loop. The loop is loaded with inductors to insure uniform and in-phase fields in the slot in order to obtain an omnidirectional radiation...

  5. Spiral finned crucible pot

    Science.gov (United States)

    Soemowidagdo, Arianto Leman; Tiwan, Widarto, Ardian, Aan

    2018-02-01

    Innovation on a crucible furnace to increase its efficiency in aluminum melting has been done. The innovation was a spiral finned crucible pot. The inclination of the spiral finned was vary of 5, 10, 15, and 20 degrees. The spiral finned effects was determined from the performance test result. A crucible pot without fin was also tested as a control. The crucible pot was examined at the same process condition. The crucible pot with the inclined fin of 10 degrees gives an optimum performance. It gives effective heating rate so that more efficient in LPG consumption. Therefore it saves energy in the aluminum melting process.

  6. 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

  7. 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.

  8. Time Slot Management in Attended Home Delivery

    NARCIS (Netherlands)

    N.A.H. Agatz (Niels); A.M. Campbell (Ann Melissa); M. Fleischmann (Moritz); M.W.P. Savelsbergh (Martin)

    2008-01-01

    textabstractMany e-tailers providing attended home delivery, especially e-grocers, offer narrow delivery time slots to ensure satisfactory customer service. The choice of delivery time slots has to balance marketing and operational considerations, which results in a complex planning problem. We

  9. 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.

  10. The spinning ball spiral

    Science.gov (United States)

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

    2010-09-01

    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.

  11. Quarkyonic Chiral Spirals

    International Nuclear Information System (INIS)

    Toru, Kojo; Hidaka, Y.; Pisarski, R.; McLerran, L.

    2010-01-01

    We argue the properties of confining dense quark matter, 'quarkyonic' matter, from the viewpoint of both bulk properties and excitation modes. After a brief review of confining aspects, the chiral breaking/restoration will be discussed. We argue that the strong infrared correlations induce the chiral spiral, i.e., the spatial modulation of the chiral condensate which breaks the chiral symmetry locally but restore it globally. The effective dimensional reduction takes place, allowing us to analyzing the system as 2D model in which several exact results can be explicitly derived. We also discuss the excitation spectra, both mesonic and baryonic ones, on the chiral spiral. (author)

  12. Vertically Polarized Omnidirectional Printed Slot Loop Antenna

    DEFF Research Database (Denmark)

    Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren H.; Thaysen, Jesper

    2015-01-01

    A novel vertically polarized omnidirectional printed slot loop antenna has been designed, simulated, fabricated and measured. The slot loop works as a magnetic loop. The loop is loaded with inductors to insure uniform and in-phase fields in the slot in order to obtain an omnidirectional radiation...... pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due to the polarization....

  13. Slot Antenna for Wireless Temperature Measurement Systems

    DEFF Research Database (Denmark)

    Acar, Öncel; Jakobsen, Kaj Bjarne

    2016-01-01

    This paper presents a novel clover-slot antenna for a surface-acoustic-wave sensor based wireless temperature measurement system. The slot is described by a parametric locus curve that has the shape of a clover. The antenna is operated at high temperatures, in rough environments, and has a 43......% fractional bandwidth at the 2.4 GHz ISM-band. The slot antenna has been optimized for excitation by a passive chip soldered onto it. Measurement results are compared with simulation results and show good agreements....

  14. A design procedure for a slotted waveguide with probe-fed slots radiating into plasma

    International Nuclear Information System (INIS)

    Colborn, J.A.

    1989-11-01

    A design procedure is developed for slotted-waveguide antennas with probe-fed slots. Radiation into a gyrotropic, plane-stratified medium is considered, nonzero waveguide wall thickness is assumed, and noncosinusoidal slot fields and arbitrary slot length up to about one free-space wavelength are allowed. External mutual coupling is taken into account by matching the tangential fields at the antenna surface. The particular case of longitudinal slots in the broad face of rectangular guide is analyzed. The motivation for this work is the design of such radiators for plasma heating and current-drive on thermonuclear fusion experiments, but some of the analysis is applicable to the probeless slotted waveguide used for avionics and communications. 20 refs., 5 figs

  15. 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...

  16. 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

  17. Spiraling into Transformative Learning

    Science.gov (United States)

    Cranton, Patricia

    2010-01-01

    This article explores how technical and vocational learning may spiral into transformative learning. Transformative learning theory is reviewed and the learning tasks of critical theory are used to integrate various approaches to transformative learning. With this as a foundation, the article explores how transformative learning can be fostered in…

  18. Archimedean Voronoi spiral tilings

    Science.gov (United States)

    Yamagishi, Yoshikazu; Sushida, Takamichi

    2018-01-01

    We study the transition of the number of spirals (called parastichy in the theory of phyllotaxis) within a Voronoi tiling for Archimedean spiral lattices. The transition of local parastichy numbers within a tiling is regarded as a transition at the base site point in a continuous family of tilings. This gives a natural description of the quasiperiodic structure of the grain boundaries. It is proved that the number of tiles in the grain boundaries are denominators of rational approximations of the argument (called the divergence angle) of the generator. The local parastichy numbers are non-decreasing functions of the plastochron parameter. The bifurcation diagram of local parastichy numbers has a Farey tree structure. We also prove Richards’ formula of spiral phyllotaxis in the case of Archimedean Voronoi spiral tilings, and show that, if the divergence angle is a quadratic irrational number, then the shapes of tiles in the grain boundaries are close to rectangles. If the divergence angle is linearly equivalent to the golden section, then the shape of tiles in the grain boundaries is close to square.

  19. 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

  20. Vertically Polarized Omnidirectional Printed Slot Loop AntennaPrinted Slot Loop Antenna (invited)

    DEFF Research Database (Denmark)

    Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren Helstrup; Thaysen, Jesper

    2015-01-01

    A novel verticall A novel vertically polarized dpolarize , omnidirection omnidirectional l , printed slot loop antenna h sprinted slot loop antenna has been designed, simulated, fabricated, and measured. The slot loop works as a magnetic loop. The loop is loaded with inductors to insure uniform...... and in-phase fields in the slot in order to obtain an omnidirectional radiation pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due...

  1. Pumping slots: impedances and power losses

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S. [Maryland Univ., College Park, MD (United States). Dept. of Physics

    1996-08-01

    Contributions of pumping slots to the beam coupling impedances and power losses in a B-factory ring are considered. While their leading contribution is to the inductive impedance, for high-intensity machines with short bunches like e{sup +}e{sup -} B-factories the real part of the impedance and related loss factors are also important. Using an analytical approach we calculate the coupling impedances and loss factors due to slots in a ring with an arbitrary cross section of the vacuum chamber. Effects of the slot tilt on the beam impedance are also considered, and restrictions on the tilt angle are derived from limitations on the impedance increase. The power leakage through the slots is discussed briefly. The results are applied to the KEK B-factory. (author)

  2. Slot Machine Response Frequency Predicts Pathological Gambling

    DEFF Research Database (Denmark)

    Linnet, Jakob; Rømer Thomsen, Kristine; Møller, Arne

    2013-01-01

    Slot machines are among the most addictive forms of gambling, and pathological gambling slot machine players represent the largest group of treatment seekers, accounting for 35% to 93% of the population. Pathological gambling sufferers have significantly higher response frequency (games / time......) on slot machines compared with non-problem gamblers, which may suggest increased reinforcement of the gambling behavior in pathological gambling. However, to date it is unknown whether or not the increased response frequency in pathological gambling is associated with symptom severity of the disorder....... This study tested the hypothesis that response frequency is associated with symptom severity in pathological gambling. We tested response frequency among twenty-two pathological gambling sufferers and twenty-one non-problem gamblers on a commercially available slot machine, and screened for pathological...

  3. 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.)

  4. 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.

  5. Spirality: A Noval Way to Measure Spiral Arm Pitch Angle

    Science.gov (United States)

    Shields, Douglas W.; Boe, Benjamin; Henderson, Casey L.; Hartley, Matthew; Davis, Benjamin L.; Pour Imani, Hamed; Kennefick, Daniel; Kennefick, Julia D.

    2015-01-01

    We present the MATLAB code Spirality, a novel method for measuring spiral arm pitch angles by fitting galaxy images to spiral templates of known pitch. For a given pitch angle template, the mean pixel value is found along each of typically 1000 spiral axes. The fitting function, which shows a local maximum at the best-fit pitch angle, is the variance of these means. Error bars are found by varying the inner radius of the measurement annulus and finding the standard deviation of the best-fit pitches. Computation time is typically on the order of 2 minutes per galaxy, assuming at least 8 GB of working memory. We tested the code using 128 synthetic spiral images of known pitch. These spirals varied in the number of spiral arms, pitch angle, degree of logarithmicity, radius, SNR, inclination angle, bar length, and bulge radius. A correct result is defined as a result that matches the true pitch within the error bars, with error bars no greater than ±7°. For the non-logarithmic spiral sample, the correct answer is similarly defined, with the mean pitch as function of radius in place of the true pitch. For all synthetic spirals, correct results were obtained so long as SNR > 0.25, the bar length was no more than 60% of the spiral's diameter (when the bar was included in the measurement), the input center of the spiral was no more than 6% of the spiral radius away from the true center, and the inclination angle was no more than 30°. The synthetic spirals were not deprojected prior to measurement. The code produced the correct result for all barred spirals when the measurement annulus was placed outside the bar. Additionally, we compared the code's results against 2DFFT results for 203 visually selected spiral galaxies in GOODS North and South. Among the entire sample, Spirality's error bars overlapped 2DFFT's error bars 64% of the time. For those galaxies in which Source code is available by email request from the primary author.

  6. Stereoscopic display in a slot machine

    Science.gov (United States)

    Laakso, M.

    2012-03-01

    This paper reports the results of a user trial with a slot machine equipped with a stereoscopic display. The main research question was to find out what kind of added value does stereoscopic 3D (S-3D) bring to slot games? After a thorough literature survey, a novel gaming platform was designed and implemented. Existing multi-game slot machine "Nova" was converted to "3DNova" by replacing the monitor with an S-3D display and converting six original games to S-3D format. To evaluate the system, several 3DNova machines were put available for players for four months. Both qualitative and quantitative analysis was carried out from statistical values, questionnaires and observations. According to the results, people find the S-3D concept interesting but the technology is not optimal yet. Young adults and adults were fascinated by the system, older people were more cautious. Especially the need to wear stereoscopic glasses provide a challenge; ultimate system would probably use autostereoscopic technology. Also the games should be designed to utilize its full power. The main contributions of this paper are lessons learned from creating an S-3D slot machine platform and novel information about human factors related to stereoscopic slot machine gaming.

  7. Logarithmic Slots Antennas Using Substrate Integrated Waveguide

    Directory of Open Access Journals (Sweden)

    Jahnavi Kachhia

    2015-01-01

    Full Text Available This paper represents new generation of slotted antennas for satellite application where the loss can be compensated in terms of power or gain of antenna. First option is very crucial because it totally depends on size of satellite so we have proposed the high gain antenna creating number of rectangular, trapezoidal, and I shape slots in logarithm size in Substrate Integrated Waveguide (SIW structure. The structure consists of an array of various shape slots antenna designed to operate in C and X band applications. The basic structures have been designed over a RT duroid substrate with dielectric constant of 2.2 and with a thickness of 0.508 mm. Multiple slots array and shape of slot effects have been studied and analyzed using HFSS (High Frequency Structure Simulator. The designs have been supported with its return loss, gain plot, VSWR, and radiation pattern characteristics to validate multiband operation. All the proposed antennas give gain more than 9 dB and return loss better than −10 dB. However, the proposed structures have been very sensitive to their physical dimensions.

  8. Band-notched spiral antenna

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. 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

  10. 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.

  11. High slot utilization systems for electric machines

    Science.gov (United States)

    Hsu, John S

    2009-06-23

    Two new High Slot Utilization (HSU) Systems for electric machines enable the use of form wound coils that have the highest fill factor and the best use of magnetic materials. The epoxy/resin/curing treatment ensures the mechanical strength of the assembly of teeth, core, and coils. In addition, the first HSU system allows the coil layers to be moved inside the slots for the assembly purpose. The second system uses the slided-in teeth instead of the plugged-in teeth. The power density of the electric machine that uses either system can reach its highest limit.

  12. Pumping slots: Coupling impedance calculations and estimates

    International Nuclear Information System (INIS)

    Kurennoy, S.

    1993-08-01

    Coupling impedances of small pumping holes in vacuum-chamber walls have been calculated at low frequencies, i.e., for wavelengths large compared to a typical hole size, in terms of electric and magnetic polarizabilities of the hole. The polarizabilities can be found by solving and electro- or magnetostatic problem and are known analytically for the case of the elliptic shape of the hole in a thin wall. The present paper studies the case of pumping slots. Using results of numerical calculations and analytical approximations of polarizabilities, we give formulae for practically important estimates of slot contribution to low-frequency coupling impedances

  13. Jets instabilities producing the slot-tone

    OpenAIRE

    Billon, Alexis; Valeau, Vincent; Sakout, Anas

    2004-01-01

    The nature of the instability governing the self-sustained tones produced by a low Mach number free plane jet impinging on a slotted plate, known as slot-tone, is identified experimentally. The experimental apparatus permits to control the Reynolds number and the distance from the jet outlet to the plate. For a Reynolds number, the shear-layer natural frequency and the jet column mode frequency of the free jet without the obstacle are estimated and compared to the minimal and maximal frequenc...

  14. Cursive word raw segmentation based on scanning Skew slots

    OpenAIRE

    Babić Ranko V.

    2006-01-01

    In this paper we present an outline of a method for low-level structural analysis of cursive words by scanning skew slots which produce histograms or word profiles. Having different angles slots can detect corresponding structural details - writing strokes and their directions. The word baseline which serves as a reference for slot angles, can be easily revealed Also from word profiles taken by different slots we can get candidate spots for preliminary word segmentation. Although very simple ...

  15. Slotting allowances to coordinate manufacturers’ retail sales effort

    OpenAIRE

    Foros, Øystein; Kind, Hans Jarle; Sand, Jan Yngve

    2007-01-01

    Slotting allowances are fees paid by manufacturers to get access to retailers’ shelf space. Although the main attention towards slotting allowances has been within the grocery industry, slotting allowances have also been applied within e.g. e-commerce and mobile telephony. In these industries we observe that distributors have large market power due to their control of access to customers. We analyse how shifting bargaining power from manufacturers to retailers and the use of slotting allowanc...

  16. A Waveguide Transverse Broad Wall Slot Radiating Between Baffles

    DEFF Research Database (Denmark)

    Dich, Mikael; Rengarajan, S.R.

    1997-01-01

    An analysis of the self impedance of waveguide-fed transverse slots radiating between baffles is presented. The region exterior to the slot is treated as a parallel plate (PP) waveguide which radiates into half space through an aperture in an infinite ground plane. The slot problem is analyzed...

  17. Impedance of a slotted-pipe kicker

    Energy Technology Data Exchange (ETDEWEB)

    Feng Zhou [Academia Sinica, Beijing, BJ (China). Inst. of High Energy Physics

    1996-08-01

    This paper introduces the principle of a new slotted kicker simply, which is made by using vacuum pipe itself with proper slits as current conductors, and then, presents a rough estimation of its longitudinal and transverse impedance, respectively. Calculation shows that its impedance is reduced significantly compared to our present air-coil kicker. (author)

  18. Of Slot Machines and Broken Test Tubes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 5. Of Slot Machines and Broken Test Tubes. S Mahadevan. General Article Volume 19 Issue 5 May 2014 pp 395-405. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/019/05/0395-0405. Keywords.

  19. Coupling Between Waveguide-Fed Slot Arrays

    Science.gov (United States)

    Rengarajan, Sembiam

    2011-01-01

    Coupling between two waveguide-fed planar slot arrays has been investigated using full-wave analysis. The analysis employs the method-of-moments solution to the pertinent coupled integral equations for the aperture electric field of all slots. In order to compute coupling between two arrays, the input port of the first array is excited with a TE(sub 10) mode wave while the second one is match-terminated. After solving the moment method matrix equations, the aperture fields of all slots are obtained and thereby the TE(sub 10) mode wave received at the input port of the second array is determined. Coupling between two arrays is the ratio of the wave amplitude arriving in the second array port to the incident wave amplitude at the first array port. The coupling mechanism has been studied as a function of spacing between arrays in different directions, e.g. the electric field plane, the magnetic field plane, and the diagonal plane. Computed coupling values are presented for different array geometries. This work is novel since it provides a good understanding of coupling between waveguide-fed slot arrays as a function of spacing and orientation for different aperture distributions and array architectures. This serves as a useful tool for antenna design engineers and system engineers.

  20. Of Slot Machines and Broken Test Tubes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 5. Of Slot Machines and Broken Test Tubes. S Mahadevan. General Article Volume 19 Issue 5 May 2014 pp 395-405. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/019/05/0395-0405. Keywords.

  1. 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.

  2. Slot antenna SIS mixers for submillimeter wavelengths

    Science.gov (United States)

    Zmuidzinas, Jonas; Leduc, Henry G.; Stern, J. A.

    1992-01-01

    We are developing improved versions of a slot antenna SIS mixer which we have previously described. The initial work demonstrated a double sideband noise temperature of 420 K for a 500 GHz quasi-optical SIS mixer employing a twin-slot antenna on a quartz dielectric substrate. A quartz hyperhemispherical lens is used to focus the incoming radiation onto the twin-slot antenna. The advantages of a twin-slot antenna include a low impedance (35 omega) and a clean, symmetric beam pattern into the dielectric with a 70 percent efficiency. In our original mixer, the radiation was coupled from the two slot antennas onto superconducting microstrip lines which fed the SIS junction. By performing an impedance transformation using tapered lines and by feeding the radiation from the two slots to the junction in parallel, the effective (real) impedance seen by the junction was reduced to just 4 omega. This very low impedance allowed a junction area of 2.3 sq micron to be used at 500 GHz, which was manufactured using optical lithography. However, no attempt was made to tune out the junction capacitance. We estimate that this capacitance reduces the impedance coupling efficiency to eta(sub Z) approx. equals 0.23, for our junction with omega R(sub N) C = 5.3 at 500 GHz. The recent development of techniques using electron-beam lithography to manufacture junctions with very small areas (approx. equals 0.1 sq microns) now allows considerably more flexibility in the design of SIS mixer circuits. We have redesigned the slot-antenna mixer to take advantage of this possibility. In particular, we have included a novel circuit which allows the junction capacitance to be tune out over a broad bandwidth. For instance, mixers designed for 800 GHz using NbN/MgO/NbN junctions with realistic parameters achieve a 3 dB impedance bandwidth of nearly 400 GHz. Furthermore, our circuit uses only short lengths of microstrip and should be less sensitive to RF losses than other designs. The improved

  3. [Influence of slot size on torque control].

    Science.gov (United States)

    Tian, Jun; Liu, Zhong-Hao; Zhang, Ding; Wu, Chuan-Jun

    2009-12-01

    To study the influence of two slot size brackets on torque control when teeth interacted in the same arch. After the upper arch was aligned and leveled in Typodont study, the inclinations of upper teeth 5 +/- 5 were measured when 0.457 2 mm x 0.635 0 mm OPA-K brackets and 0.558 8 mmx0.711 2 mm OPA-K brackets were filled with 0.431 8 mm x 0.635 0 mm stainless steel wire. This experiment was duplicated 10 times. The inclin of each tooth were transformed to the absolute values of the torque play angle psi by computing program, and paired-t test was used. The two kinds of slot size brackets were different with statistical significance on torque control. When the brackets were filled with 0.431 8 mm x 0.635 0 mm stainless steel wire, the absolute values of the angle psi in 0.558 8 mm x 0.711 2 mm and 0.457 2 mm x 0.635 0 mm slot size brackets were 6.140 degrees +/- 3.758 degrees and 2.608 degrees +/- 1.479 degrees respectively, and the average difference of that between the two slot size brackets was 3.532 degrees. The absolute values of the angle psi in the upper left and right canine brackets were 2.560 degrees +/- 2.605 degrees, 4.230 degrees +/- 2.817 degrees, 1.260 degrees +/- 0.747 degrees and 2.070 degrees +/- 0.663 degrees respectively, and average differences between them were smaller than that in the other teeth. There was difference between the two kinds of slot size brackets on torque control, and 0.457 2 mm x 0.635 0 mm slot size bracket controls torque better when filled with the same size wire. In this study, the teeth interaction in the same arch probably caused the result that the difference of two slot size brackets on torque control was less than the study results of the theory calculations and material studys before.

  4. Hurricane Spiral Bands.

    Science.gov (United States)

    Guinn, Thomas A.; Schubert, Wayne H.

    1993-10-01

    The spiral bands that occur in tropical cyclones can be conveniently divided into two classes-outer bands and inner bands. Evidence is presented here that the outer bands form as the result of nonlinear effects during the breakdown of the intertropical convergence zone (ITCZ) through barotropic instability. In this process a zonal strip of high potential vorticity (the ITCZ shear zone or monsoon trough) begins to distort in a varicose fashion, with the potential vorticity (PV) becoming pooled in local regions that are connected by filaments of high PV. As the pooled regions become more axisymmetric, the filaments become thinner and begin to wrap around the PV centers.It is argued that inner bands form in a different manner. As a tropical cyclone intensifies due to latent heat release, the PV field becomes nearly circular with the highest values of PV in the cyclone center. The radial gradient of PV provides a state on which PV waves (the generalization of Rossby waves) can propagate. The nonlinear breaking of PV waves then leads to an irreversible distortion of the PV contours and a downgradient flux of PV. The continuation of this proem tends to erode the high PV core of the tropical cyclone, to produce a surrounding surf zone, and hence to spread the PV horizontally. In a similar fashion, inner bands can also form by the merger of a vortex with a patch of relatively high PV air. As the merger proem occurs the patch of PV is quickly elongated and wrapped around the vortex. The resulting vortex is generally larger in horizontal extent and exhibits a spiral band of PV.When the formation of outer and inner bands is interpreted in the context of a normal-mode spectral model, they emerge as slow manifold phenomena; that is, they have both rotational and (balanced or slaved) gravitational mode aspects. In this sense, regarding them as simply gravity waves leads to an incomplete dynamical picture.

  5. Slot Machine Response Frequency Predicts Pathological Gambling

    DEFF Research Database (Denmark)

    Linnet, Jakob; Rømer Thomsen, Kristine; Møller, Arne

    2013-01-01

    ) on slot machines compared with non-problem gamblers, which may suggest increased reinforcement of the gambling behavior in pathological gambling. However, to date it is unknown whether or not the increased response frequency in pathological gambling is associated with symptom severity of the disorder....... This study tested the hypothesis that response frequency is associated with symptom severity in pathological gambling. We tested response frequency among twenty-two pathological gambling sufferers and twenty-one non-problem gamblers on a commercially available slot machine, and screened for pathological...... gambling symptom severity using the South Oaks Gambling Screen (SOGS). The results showed that pathological gambling sufferers had significantly higher response frequency than non-problem gamblers, and that response frequency was significantly correlated with SOGS symptom severity among pathological...

  6. Measuring with the spiral reader

    CERN Multimedia

    1974-01-01

    The spiral reader shown here was at the time, together with the Shivamatic scanning system, the basic equipment used for measuring bubble chamber pictures. Anne Anton sits at the table. (See Photo Archive 7408343.)

  7. 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.

  8. Spiral inlets for steam turbines

    Science.gov (United States)

    Škach, Radek; Uher, Jan

    2017-09-01

    This paper deals with the design process of special nozzle blades for spiral inlets. Spiral inlets are used for the first stages of high pressure and intermediate pressure steam turbines with both reaction and impulse blades when throttling or sliding pressure control is applied. They improve the steam flow uniformity from the inlet pipe and thus decrease the aerodynamic losses. The proposed evaluation of the inlet angle is based on the free vortex law.

  9. Congestion Pricing for Aircraft Pushback Slot Allocation.

    Directory of Open Access Journals (Sweden)

    Lihua Liu

    Full Text Available In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the "external cost of surface congestion" is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm.

  10. Pressure distribution over an NACA 23012 airfoil with a fixed slot and a slotted flap

    Science.gov (United States)

    Harris, Thomas A; Lowry, John G

    1942-01-01

    Report presents the results of a pressure-distribution investigation conducted in the Langley Memorial Aeronautical Laboratory 7 by 10-foot wind tunnel to determine the air loads on an NACA 23012 airfoil in combination with a fixed leading-edge slot and a slotted flap. Pressures were measured over the upper and lower surfaces of the component parts of the combination for several angles of attack and at several flap settings. The data, presented as pressure diagrams and graphs of section coefficients, are applicable to rib, slat, and flap designs for the combination.

  11. Airflow patterns in a slot-ventilated enclosure partially loaded with empty slotted boxes

    International Nuclear Information System (INIS)

    Tapsoba, Mitoubkieta; Moureh, Jean; Flick, Denis

    2007-01-01

    A reduced-scale model and CFD predictions were used to investigate experimentally and numerically the airflow patterns within a ceiling-slot ventilated enclosure loaded by slotted boxes. The experiments were carried out with a laser Doppler anemometer. This paper concerns the air velocity characteristics within the jet and outside the boxes. Results make it possible to highlight the confinement effect due to enclosure and the influence of load porosity on the jet penetration, its development and hence the heterogeneity of ventilation within the enclosure. The numerical predictions obtained with the computational fluid dynamics Fluent package using the RSM turbulence model show rather good agreement with experimental data

  12. Slot-coupled CW standing wave accelerating cavity

    Science.gov (United States)

    Wang, Shaoheng; Rimmer, Robert; Wang, Haipeng

    2017-05-16

    A slot-coupled CW standing wave multi-cell accelerating cavity. To achieve high efficiency graded beta acceleration, each cell in the multi-cell cavity may include different cell lengths. Alternatively, to achieve high efficiency with acceleration for particles with beta equal to 1, each cell in the multi-cell cavity may include the same cell design. Coupling between the cells is achieved with a plurality of axially aligned kidney-shaped slots on the wall between cells. The slot-coupling method makes the design very compact. The shape of the cell, including the slots and the cone, are optimized to maximize the power efficiency and minimize the peak power density on the surface. The slots are non-resonant, thereby enabling shorter slots and less power loss.

  13. G-Tunnel pressurized slot-testing preparations

    International Nuclear Information System (INIS)

    Zimmerman, R.M.; Sifre-Soto, C.; Mann, K.L.; Bellman, R.A. Jr.; Luker, S.; Dodds, D.J.

    1992-04-01

    Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National laboratories elected to conduct a development program on pressurized slot testing and featured (1) development of an improved method to cut slots using a chain saw with diamond-tipped cutters, (2) measurements useful for determining in situ stresses normal to slots, (3) measurements applicable for determining the in situ modulus of deformation parallel to a drift surface, and (4) evaluations of the potentials of pressurized slot strength testing. This report describes the preparations leading to the measurements and evaluations

  14. Spiral Inflector For Compact Cyclotron

    CERN Document Server

    Karamysheva, G A

    2004-01-01

    Compact cyclotron for explosives detection by nuclear resonance absorption of γ-rays in nitrogen is under development [1] Cyclotron will be equipped with the external ion source. The injection system consists of a double-drift beam bunching system, a spiral inflector, beam diagnostics, focusing and adjustment elements [2]. The spiral inflector for ion bending from axial to median plane is used. Computer model of spiral inflector for the Customs cyclotron is developed. 3D electrostatic field calculations of the designed inflector are performed. Calculated electric field map and magnetic field map of the cyclotron [3] are used for beam dynamic simulations. Numeric simulations are carried out for 500 particles using code for calculation of particle dynamics by integration of differential equations in Cartesian coordinate system written in MATLAB. Direct Coulomb particle-to-particle method is used to take into account space-charge effects.

  15. GANIL-SPIRAL1-SPIRAL2: Highlights and Perspectives

    Science.gov (United States)

    Gales, S.

    2010-06-01

    GANIL presently offers unique opportunities in nuclear physics and many other fields that arise from not only the provision of low-energy stable beams, fragmentation beams and re-accelerated radioactive species, but also from the availability of a wide range of state-of-the-art spectrometers and instrumentation. A few examples of recent highlights are presented. With the construction of SPIRAL2 over the next few years, GANIL is in a good position to retain its world-leading capability. As selected by the ESFRI committee, the next generation of ISOL facility in Europe is represented by the SPIRAL2 project to be built at GANIL (Caen, France). SPIRAL 2 is based on a high power, CW, superconducting LINAC, delivering 5 mA of deuteron beams at 40 MeV (200 KW) directed on a C converter+ Uranium target and producing therefore more 1013 fissions/s. The expected radioactive beams intensities in the mass range from A = 60 to A = 140, will surpass by two order of magnitude any existing facilities in the world. These unstable atoms will be available at energies between few KeV/n to 15 MeV/n. The same driver will accelerate high intensity (100*A to 1 mA), heavier ions (Ar up to Xe) at maximum energy of 14 MeV/n. Under the 7FP program of European Union called*Preparatory phase*, the SPIRAL2 project has been granted a budget of about 4 M€ to build up an international consortium around this new venture. The status of the construction of SPIRAL2 accelerator and associated physics instruments in collaboration with EU and International partners will be presented.

  16. 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

  17. 49 CFR 236.809 - Signal, slotted mechanical.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Signal, slotted mechanical. 236.809 Section 236.809 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic device...

  18. Dowel Type Connections with Slotted-in Steel Plates

    DEFF Research Database (Denmark)

    Pedersen, Martin Bo Uhre; Clorius, Christian Odin; Damkilde, Lars

    1999-01-01

    failure, as is shown in test series on smaller specimens with slotted-in steel plates. The scope of the present investigation is to trace the effect of eccentric transverse loading of full scale connections with slotted-in steel plates primarily loaded in the grain direction....

  19. Evaluation of two styles of slotted, flat-head screws

    International Nuclear Information System (INIS)

    Reeves, C.A. Jr.; Johnson, W.B.

    1979-01-01

    A series of torque tests were performed to evaluate the relative merits of two different flat-head screws fabricated from a uranium--6% niobium alloy. The screws tested were machined with both normal, straight-through slots in the head and with slots having radiused bottoms. Test results indicate that both designs easily surpass the required 20-inch-pound-proof torque

  20. 14 CFR 93.221 - Transfer of slots.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Transfer of slots. 93.221 Section 93.221 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC... any time period and they may be traded in any combination for slots at the same airport or any other...

  1. Inspired Spirals. Teaching Art with Art.

    Science.gov (United States)

    Hubbard, Guy

    2001-01-01

    Discusses spirals in nature, man-made objects, and art. Focuses on art that incorporates the spiral, including works by M. C. Escher and Frank Lloyd Wright, an African headdress, and a burial urn. Describes activities to help students make spirals of their own, such as constructing a coil clay pot. (CMK)

  2. Slot Optimization Design of Induction Motor for Electric Vehicle

    Science.gov (United States)

    Shen, Yiming; Zhu, Changqing; Wang, Xiuhe

    2018-01-01

    Slot design of induction motor has a great influence on its performance. The RMxprt module based on magnetic circuit method can be used to analyze the influence of rotor slot type on motor characteristics and optimize slot parameters. In this paper, the authors take an induction motor of electric vehicle for a typical example. The first step of the design is to optimize the rotor slot by RMxprt, and then compare the main performance of the motor before and after the optimization through Ansoft Maxwell 2D. After that, the combination of optimum slot type and the optimum parameters are obtained. The results show that the power factor and the starting torque of the optimized motor have been improved significantly. Furthermore, the electric vehicle works at a better running status after the optimization.

  3. Slotted Circularly Polarized Microstrip Antenna for RFID Application

    Directory of Open Access Journals (Sweden)

    S. Kumar

    2017-12-01

    Full Text Available A single layer coaxial fed rectangular microstrip slotted antenna for circular polarization (CP is proposed for radio frequency identification (RFID application. Two triangular shaped slots and one rectangular slot along the diagonal axis of a square patch have been embedded. Due to slotted structure along the diagonal axis and less surface area, good quality of circular polarization has been obtained with the reduction in the size of microstrip antenna by 4.04 %. Circular polarization radiation performance has been studied by size and angle variation of diagonally slotted structures. The experimental result found for 10-dB return loss is 44 MHz with 10MHz of 3dB Axial Ratio (AR bandwidth respectively at the resonant frequency 910 MHz. The overall proposed antenna size including the ground plane is 80 mm x 80 mm x 4.572 mm.

  4. Metal membrane with dimer slots as a universal polarizer

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei; Zalkovskij, Maksim; Malureanu, Radu

    2014-01-01

    for the electromagnetic response of an arbitrary dimer based on the Green functions approach. The theory confirms that a great variety of polarization properties, such as birefringence, chirality and elliptical dichroism, can be achieved in a metal layer with such slot-dimer patterning (i.e. in a metasurface). Optical......In this work, we show theoretically and confirm experimentally that thin metal membranes patterned with an array of slot dimers (or their Babinet analogue with metal rods) can function as a versatile spectral and polarization filter. We present a detailed covariant multipole theory...... properties of the metasurface can be extensively tuned by varying the geometry (shape and dimensions) of the dimer, for example, by adjusting the sizes and mutual placement of the slots (e.g. inter-slot distance and alignment angle). Three basic shapes of dimers are analyzed: II-shaped (parallel slots), V...

  5. 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.

  6. 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.)

  7. Student-Led Objective Tutorial (SLOT) in Medical Education.

    Science.gov (United States)

    Sivagnanam, Gurusamy; Saraswathi, Simansalam; Rajasekaran, Aiyalu

    2006-12-01

    Purpose - To assess an innovative tutoring program named 'Student-Led Objective Tutorial' (SLOT) among undergraduate medical students. Method - The program was conceptualized by the Pharmacology Unit of Faculty of Medicine and Health Sciences, Asian Institute of Medicine Science & Technology (AIMST), Malaysia and implemented in the middle of 2005. A cohort of 246 medical undergraduate students (spread across 5 consecutive batches) participated. Following a brief explanation on the purpose and nature of SLOT, each batch was divided into small groups and was given a reading assignment on 4 previously delivered lecture topics. Each group was asked to prepare 3-5 multiple choice questions (MCQs) of their own in PowerPoint format to be presented, in turns, to the whole class on the day of SLOT. The proceedings were facilitated by 2 lecturers. Student feedback on the efficacy and benefits were assessed through an anonymous self administered questionnaire. Results - About 76% (188) of the students favored SLOT. The acceptance rate of SLOT was higher among males. There was no significant difference between batches in their opinions on whether to pursue SLOT in future. The most prevalent positive comment was that SLOT enhanced learning skills, and the negative comment being, it consumed more time. Conclusions - SLOT is a novel tutorial method which can offset faculty shortage with advantages like enhanced interest among teachers and learners, uniform reach of content, opportunities for group learning, and involvement of visual aids as teaching-learning (T-L) method. SLOT unraveled the students' potential of peer tutoring both inside as well as outside the classroom. Consumer tutors (students) can be tapped as a resource for SLOT for all subjects and courses in healthcare teaching.

  8. Block division carrier slot setting for satellite SCPC systems

    Science.gov (United States)

    Yashima, Hiroyuki; Sasase, Iwao; Mori, Shinsaku

    1991-01-01

    A carrier slot setting plan is proposed to reduce intermodulation (IM) effects for satellite single-channel-per-carrier (SCPC) systems. Carrier slots are divided into blocks and slight frequency gaps are set among blocks. This setting introduces frequency offset between the center frequencies of carrier slots and the center frequencies of the IM components. A method of deriving optimum division in order to derive the upper bound of improvement of the C/IM ratio in the worst channel is developed. The results show that the setting plan achieves significant improvement of IM effects at a cost of only slight bandwidth expansion, even in fully loaded SCPC systems.

  9. Period Estimation in Astronomical Time Series Using Slotted Correntropy

    Science.gov (United States)

    Huijse, Pablo; Estevez, Pablo A.; Zegers, Pablo; Principe, José C.; Protopapas, Pavlos

    2011-06-01

    In this letter, we propose a method for period estimation in light curves from periodic variable stars using correntropy. Light curves are astronomical time series of stellar brightness over time, and are characterized as being noisy and unevenly sampled. We propose to use slotted time lags in order to estimate correntropy directly from irregularly sampled time series. A new information theoretic metric is proposed for discriminating among the peaks of the correntropy spectral density. The slotted correntropy method outperformed slotted correlation, string length, VarTools (Lomb-Scargle periodogram and Analysis of Variance), and SigSpec applications on a set of light curves drawn from the MACHO survey.

  10. 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

  11. 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.

  12. Modeling of Slot Waveguide Sensors Based on Polymeric Materials

    Science.gov (United States)

    Bettotti, Paolo; Pitanti, Alessandro; Rigo, Eveline; De Leonardis, Francesco; Passaro, Vittorio M. N.; Pavesi, Lorenzo

    2011-01-01

    Slot waveguides are very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper we have carried out a detailed analysis of mode confinement properties in slot waveguides realized in very low refractive index materials. We show that the sensitivity of a slot waveguide is not directly related to the refractive index contrast of high and low materials forming the waveguide. Thus, a careful design of the structures allows the realization of high sensitivity devices even in very low refractive index materials (e.g., polymers) to be achieved. Advantages of low index dielectrics in terms of cost, functionalization and ease of fabrication are discussed while keeping both CMOS compatibility and integrable design schemes. Finally, applications of low index slot waveguides as substitute of bulky fiber capillary sensors or in ring resonator architectures are addressed. Theoretical results of this work are relevant to well established polymer technologies. PMID:22164020

  13. Adaptive Drainage Slots for Acoustic Noise Attenuation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group, Inc. (CRG), proposes to demonstrate feasibility in the reduction of noise attributed to drainage slots in jet engine acoustic liners....

  14. Adaptive Drainage Slots for Acoustic Noise Attenuation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group, Inc. (CRG) demonstrated feasibility in the reduction of noise attributed to drainage slots in jet engine acoustic liners. This was...

  15. Market Mechanisms for Airspace Flow Program Slots, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Metron Aviation, Inc. proposes to design a system to support a marketplace in which flight operators can exchange arrival slots in traffic flow management (TFM)...

  16. Market Mechanisms for Airspace Flow Program Slots, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to design a system to support a marketplace in which flight operators can exchange arrival slots in traffic flow management (TFM) initiatives such as...

  17. Coded Slotted ALOHA with Varying Packet Loss Rate across Users

    OpenAIRE

    Stefanovic, Cedomir; Popovski, Petar

    2013-01-01

    The recent research has established an analogy between successive interference cancellation in slotted ALOHA framework and iterative belief-propagation erasure-decoding, which has opened the possibility to enhance random access protocols by utilizing theory and tools of erasure-correcting codes. In this paper we present a generalization of the and-or tree evaluation, adapted for the asymptotic analysis of the slotted ALOHA-based random-access protocols, for the case when the contending users ...

  18. 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.)

  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. 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.

  1. The DESIR Facility at SPIRAL2

    Indian Academy of Sciences (India)

    Beams from the low-energy branch of the separator spectrometer S3 and from SPIRAL1 will allow complementary studies of refrac- tory elements produced by means of fusion reactions as well as of light and intense exotic beams, respectively. Keywords. SPIRAL2; low-energy facility; nuclear physics; weak interaction; astro-.

  2. 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

  3. 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.

  4. 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 ...

  5. Geothermal reservoirs. Position of slotted section of the tube casing

    International Nuclear Information System (INIS)

    Carotenuto, A.; Vanoli, L.; Casarosa, C.

    1999-01-01

    In the present work the authors have verified the influence of the position of slotted section casing on heat rate drawn by plants for exploitation of geothermal reservoirs that use heat exchangers placed at the bottom of the well (DHE). This study have been done modelling numerically the aquifer, by means of finite element method, evaluating the heat rate drawn by the heat exchanger at different position of the slotted section of the tube casing. Numerical calculations have allowed to show the influence of the main characteristics of the aquifer and of the main characteristics of the aquifer and of the plant on design of the slotted section of the tube casing. In particular, the authors have studied the influence of i) equivalent conductivity and permeability of the aquifer, ii) mass flow rate and the inlet and outlet aquifer temperature difference in the well, iii) the ratio between the length of the slotted section and the thickness of the geothermal layer, varying the position of the slotted section of the tube casing in the aquifer [it

  6. Slot film cooling: A comprehensive experimental characterization

    Science.gov (United States)

    Raffan, Fernando

    When components of a propulsion system are exposed to elevated flow temperatures there is a risk for catastrophic failure if the components are not properly protected from the thermal loads. Among several strategies, slot film cooling is one of the most commonly used, yet poorly understood active cooling techniques. Tangential injection of a relatively cool fluid layer protects the surface(s) in question, but the turbulent mixing between the hot mainstream and cooler film along with the presence of the wall presents an inherently complex problem where kinematics, thermal transport and multimodal heat transfer are coupled. Furthermore, new propulsion designs rely heavily on CFD analysis to verify their viability. These CFD models require validation of their results, and the current literature does not provide a comprehensive data set for film cooling that meets all the demands for proper validation, namely a comprehensive (kinematic, thermal and boundary condition data) data set obtained over a wide range of conditions. This body of work aims at solving the fundamental issue of validation by providing high quality comprehensive film cooling data (kinematics, thermal mixing, heat transfer). 3 distinct velocity ratios (VR=u c/uinfinity) are examined corresponding to wall-wake (VR˜0.5), min-shear (VR ˜ 1.0), and wall-jet (VR˜2.0) type flows at injection, while the temperature ratio TR= Tinfinity/Tc is approximately 1.5 for all cases. Turbulence intensities at injection are 2-4% for the mainstream (urms/uinfinity, vrms/uinfinity,), and on the order of 8-10% for the coolant (urms/uc, vrms/uc,). A special emphasis is placed on inlet characterization, since inlet data in the literature is often incomplete or is of relatively low quality for CFD development. The data reveals that min-shear injection provides the best performance, followed by the wall-jet. The wall-wake case is comparably poor in performance. The comprehensive data suggests that this relative performance

  7. Le réseau d'échanges des savoirs de belleville e ménilmontant: uma discussão sobre associativismo e reciprocidade no mundo contemporâneo

    Directory of Open Access Journals (Sweden)

    Laura Graziela Gomes

    2001-12-01

    Full Text Available O presente artigo tem como objetivo tecer algumas reflexões sobre os modos de apropriação locais de uma forma associativa francesa específica - le réseau d' échanges des savoirs - de Belleville e Ménilmontant, dois quartiers populares, sediados no leste parisiense. A partir de minha experiência como participante do reseau, observações e conversas com os demais participantes, conclui que, basicamente, tratam-se de dois modos: o primeiro, relativo à produção de localidade, da condição de pertença dos moradores do quartier; o segundo, relativo à produção de capital social, traduzido em confiança e, por sua vez, formas de cooperação. O importante a ser ressaltado é que esses dois modos de apropriação não são exclusivos, ambos convivem, fundem- se e se interpenetram.

  8. Low profile frequency agile MIMO slot antenna with TCM characterization

    KAUST Repository

    Ghalib, Asim

    2017-06-07

    In this paper, a frequency reconfigurable multiple-input-multiple-output (MIMO) slot antenna is presented. The proposed design is low profile and compact with wide tunability range, covering several well-known frequency bands from 1800 MHz to 2450 MHz. The frequency reconfigurability is achieved by loading the annular slot with varactor diodes. The antenna system is also analyzed for MIMO performance metrics. Moreover, the effect of circular slot antenna on the chassis modes is also investigated using the theory of characteristic modes (TCM). The physical principle behind frequency reconfigurability is also investigated using TCM analysis. An interesting finding is observed using varactor diodes for frequency reconfigurability, that is the reactive impedance loading does not alter the modal significance (MS) plots but only aid in the input impedance matching at different frequency bands.

  9. Ultra-wideband antipodal slot antenna with improved radiation performance

    Science.gov (United States)

    Lu, Wen-Jun; Cheung, William S. W.; Cheng, Yong; Zhu, Hong-Bo

    2012-09-01

    A novel antipodal wide-slot antenna for ultra-wideband (UWB) applications is proposed and studied in detail. The antenna is fed by a microstrip line terminated with a rectangular tuning patch. An antipodal structure is employed to improve the radiation performances. The return losses, surface E-field, current distribution, radiation patterns and gains of the antenna are numerically and experimentally investigated. Results show that the proposed antipodal antenna has an impedance bandwidth from 0.79 to 4.0 GHz, which is about 5:1. Compared with conventional rectangular wide-slot antenna, more stable radiation pattern with lower cross-polarisation level and flatter gain variation over a 3:1 bandwidth can be obtained. Thus, the proposed antenna should be more suitable for future UWB-multiple-input multiple-output applications using polarisation diversity than conventional UWB rectangular slot antennas.

  10. Design of clover slot antenna for biomedical applications

    Directory of Open Access Journals (Sweden)

    S. Ashok Kumar

    2017-09-01

    Full Text Available A new clover slot antenna operating at 2.45 GHz Industrial, Scientific, and Medical (ISM band for biomedical applications is presented and experimentally verified. By putting a single feed and truncating clover slots with extra perturbation, good performance of polarization can be achieved. Also, the miniaturized size of the proposed antenna is 14 × 12 × 0.8 mm3 by utilizing the clover shaped slots. A broader bandwidth of 2.5 GHz is obtained for reflection coefficient less than −10 dB. In addition, the radiation pattern of proposed antenna exhibits the maximum gain of −6 dBi.

  11. Slotted Blades Savonius Wind Turbine Analysis by CFD

    Directory of Open Access Journals (Sweden)

    Andrea Alaimo

    2013-12-01

    Full Text Available In this paper a new bucket configuration for a Savonius wind generator is proposed. Numerical analyses are performed to estimate the performances of the proposed configuration by means of the commercial code COMSOL Multiphysics® with respect to Savonius wind turbine with overlap only. Parametric analyses are performed, for a fixed overlap ratio, by varying the slot position; the results show that for slot positioned near the blade root, the Savonius rotor improves performances at low tip speed ratio, evidencing a better starting torque. This circumstance is confirmed by static analyses performed on the slotted blades in order to investigate the starting characteristic of the proposed Savonius wind generator configuration.

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

    Directory of Open Access Journals (Sweden)

    Deta Rachmat Andika

    2017-01-01

    Full Text Available 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 juga mempunyai kelemahan jika dibandingkan dengan straight bevel gear. Selain proses manufaktur yang lebih rumit, profil lengkung gigi spiral ini membuat distribusi tegangan yang terjadi menjadi lebih rumit untuk dimodelkan dengan persamaan matematika. Salah satu pendekatan yang dapat dilakukan adalah dengan menggunakan metode elemen hingga. Penelitian diawali dengan membuat model dari straight bevel gear dan juga spiral bevel gear yang sudut spiralnya divariasikan 20, 35, dan 45 derajat. Model dibuat dengan dimensi yang sama baik diameter maupun jumlah gigi gear. Langkah selanjutnya yaitu perhitungan analitis pada straight bevel gear dimana hasilnya akan dibandingkan dengan hasil simulasi statis. Setelah eror yang terjadi dibawah 15% maka dilakukan simulasi dinamis pada semua model yang telah dibuat yaitu straight bevel dan juga spira bevel gear. Hasil yang didapatkan dari penelitian ini adalah secara keseluruhan spiral bevel gear lebih kuat daripada straight bevel gear pada dimensi dan beban yang sama jika dilihat dari lebih kecilnya tegangan bending dan tegangan kontak maksimum yang terjadi. Tegangan terbesar terjadi pada jenis straight bevel gear baik pada tegangan bending maupun tegangan kontak sedangkan spiral bevel gear dengan variasi sudut Seiring spiral 35 mempunyai nilai tegangan terkecil. Prosntase selisih tegangan bending maksimum yang terjadi antara straight bevel gear dan spiral bevel gear dengan variasi sudut spiral 35 derajat  sebesar 44

  13. On Density Waves in Spiral Galaxies

    Science.gov (United States)

    Grosbol, P.; Patsis, P. A.

    The spiral structure of five ordinary spiral galaxies was studied using deep BVIK' surface photometry maps obtained at the 2.2m ESO/MPI telescope. The detailed shape of the arms was analyzed in terms of the spiral density wave theory. Grand design spirals were found on the K' maps in all five galaxies although at least two would be classified as flocculent on the blue images. In several of the galaxies, bulges with weak oval distortion (~10%) were observed. Dust spirals also continue, in some cases, inside the ILR where the stellar arms terminate. This emphasizes the strong bias of morphological classifications of spiral galaxies based on blue image due to dust and young stars. The 2--armed spirals were systematically found to be wound tighter on I than on K' maps suggesting the existence of a density wave. Locations of the ILR and the 4/1 resonance were estimated based on the arm morphology and the amplitude ratio between the m = 2,4 Fourier components. The wavenumber of the stellar 2--armed pattern is increasing towards the ILR which could suggest that the density wave is associated to the long waved branch of the dispersion relation. A possible scenario is discussed.

  14. Spiral arms in thermally stratified protoplanetary discs

    Science.gov (United States)

    Juhász, Attila; Rosotti, Giovanni P.

    2018-02-01

    Spiral arms have been observed in nearly a dozen protoplanetary discs in near-infrared scattered light and recently also in the submillimetre continuum. While one of the most compelling explanations is that they are driven by planetary or stellar companions, in all but one cases such companions have not yet been detected and there is even ambiguity on whether the planet should be located inside or outside the spirals. Here, we use 3D hydrodynamic simulations to study the morphology of spiral density waves launched by embedded planets taking into account the vertical temperature gradient, a natural consequence of stellar irradiation. Our simulations show that the pitch angle of the spirals in thermally stratified discs is the lowest in the disc mid-plane and increases towards the disc surface. We combine the hydrodynamic simulations with 3D radiative transfer calculations to predict that the pitch angle of planetary spirals observed in the near-infrared is higher than in the submillimetre. We also find that in both cases the spirals converge towards the planet. This provides a new powerful observational method to determine if the perturbing planet is inside or outside the spirals, as well as map the thermal stratification of the disc.

  15. Analysis and design of broadband U-slot cut rectangular microstrip ...

    Indian Academy of Sciences (India)

    AMIT A DESHMUKH

    2017-07-15

    Jul 15, 2017 ... inductance due to longer feed, leading to better input impedance matching [1–9]. Further increase in the band- width (BW) of U-slot cut MSA is obtained by cutting asymmetrical U-slot or by cutting second U-slot inside the first one [10, 11]. Due to the presence of three resonant modes, asymmetric U-slot cut ...

  16. Analysis and design of broadband U-slot cut rectangular microstrip ...

    Indian Academy of Sciences (India)

    AMIT A DESHMUKH

    2017-07-15

    Jul 15, 2017 ... Abstract. Broadband microstrip antenna using variations of U-slot has been widely reported. However, in most of the reported work, an in-depth explanation about the mode introduced by U-slot and procedure to design. U-slot cut antennas at any given frequency is not explained. In this paper, first an ...

  17. 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...

  18. 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...

  19. 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.

  20. Broadband, Low Sidelobe, Zero Height, Slotted Circular Disk Antenna

    African Journals Online (AJOL)

    A rigorous mathematical theory for a rotationally symmetrical slotted circular disk antenna was developed. The theory applies the principle of "Gradient Invariance" of electromagnetic fields to determine the field components that are unique and single valued at any point in space. To detemine the radiation characteristics of ...

  1. Low-loss intersection of subwavelength plasmonic slot waveguides

    DEFF Research Database (Denmark)

    Xiao, Sanshui; Mortensen, Niels Asger

    2008-01-01

    The properties of crossing for two perpendicular subwavelength plasmonic slot waveguides are theoretically investigated. Results show when encountering a nano intersection the crosstalk for the direct crossing is around 25%, almost the same as throughput. In terms of symmetry considerations and r...

  2. A GRASP algorithm for the container stowage slot planning problem

    DEFF Research Database (Denmark)

    Parreno, Francisco; Pacino, Dario; Alvarez-Valdes, Ramon

    2016-01-01

    This work presents a generalization of the Slot Planning Problem which raises when the liner shipping industry needs to plan the placement of containers within a vessel (stowage planning). State-of-the-art stowage planning relies on a heuristic decomposition where containers are first distributed...

  3. Realistic Free-Spins Features Increase Preference for Slot Machines.

    Science.gov (United States)

    Taylor, Lorance F; Macaskill, Anne C; Hunt, Maree J

    2017-06-01

    Despite increasing research into how the structural characteristics of slot machines influence gambling behaviour there have been no experimental investigations into the effect of free-spins bonus features-a structural characteristic that is commonly central to the design of slot machines. This series of three experiments investigated the free-spins feature using slot machine simulations to determine whether participants allocate more wagers to a machine with free spins, and, which components of free-spins features drive this preference. In each experiment, participants were exposed to two computer-simulated slot machines-one with a free-spins feature or similar bonus feature and one without. Participants then completed a testing phase where they could freely switch between the two machines. In Experiment 1, participants did not prefer the machine with a simple free-spins feature. In Experiment 2 the free-spins feature incorporated additional elements such as sounds, animations, and an increased win frequency; participants preferred to gamble on this machine. The Experiment 3 "bonus feature" machine resembled the free spins machine in Experiment 2 except spins were not free; participants showed a clear preference for this machine also. These findings indicate that (1) free-spins features have a major influence over machine choice and (2) the "freeness" of the free-spins bonus features is not an important driver of preference, contrary to self-report and interview research with gamblers.

  4. G-tunnel pressurized slot-testing evaluations

    International Nuclear Information System (INIS)

    Zimmerman, R.M.; Sifre-Soto, C.; Mann, K.L.; Bellman, R.A. Jr.; Luker, S.; Dodds, D.J.

    1992-04-01

    Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National Laboratories elected to conduct a development program to enhance mechanical-type measurements. The program was focused on pressurized slot testing and featured (1) development of an improved method to cut slots using a chain saw with diamond-tipped cutters, (2) measurements useful for determining in situ stresses normal to slots, (3) measurements applicable for determining the in situ modulus of deformation parallel to a drift surface, and (4) evaluations of pressurized slot strength testing results and methods. This report contains data interpretation and evaluations. Included are recommendations for future efforts. This third report contains the interpretations of the testing with emphasis on the measurement results as they apply to describing rock behavior. In particular, emphases are placed on (1) normal stress determinations using the flatjack cancellation (FC) method, (2) modulus of deformation determinations, and (3) high pressure investigations. Most of the material in the first two reports is not repeated here. Appropriate data are repeated in tabular form

  5. Probabilistic Dynamic Framed Slotted ALOHA for RFID Tag Identification

    DEFF Research Database (Denmark)

    Nguyen, Chuyen T.; Hayashi, Kazunori; Kaneko, Megumi

    2013-01-01

    In this paper, we study radio frequency identification tag identification problems using framed slotted ALOHA protocol. Each tag will be assumed to participate in the contention with a certain probability. Then, the frame size and the probability will be dynamically controlled by the reader in ev...

  6. Induction Motor Speed Estimator Using Rotor Slot Harmonics

    Directory of Open Access Journals (Sweden)

    RATA, G.

    2009-02-01

    Full Text Available This paper presents a solution for the estimation of induction machine rotor speed utilizing harmonic saliencies created by rotor and stator slotting. This solution purposes to add a carrier-signal voltage at the fundamental excitation. We obtain a carrier-signal current that contains the spatial information. The PWM reference voltage is calculated with DSP - ADMC401, from Analog Device.

  7. RSBP: a reliable slotted broadcast protocol in wireless sensor networks.

    Science.gov (United States)

    Vinh, Phan Van; Oh, Hoon

    2012-10-31

    In wireless sensor networks for monitoring and control applications, a sink node needs to disseminate messages to all nodes to acquire monitoring data or to control the operation of sensor nodes. The basic flooding protocol suffers from low transmission reliability in broadcasting messages due to the hidden terminal problem. Besides, it can cause the broadcast storm problem by having many nodes rebroadcast the received message simultaneously. In order to resolve these problems while minimizing energy consumption in delivery of broadcast messages, we propose a reliable slotted broadcast protocol (RSBP) that allocates broadcast time slots to nodes based on their slot demands and then allows every node to transmit its broadcast message within the allocated slots. Then, every node can broadcast messages safely in a contention-free manner. Moreover, RSBP can be deployed easily since it does not have any specific requirements such as GPS, multi-channels and directional antennas that may not be always available in real scenarios. We show by experimental study that RSBP significantly outperforms other broadcast protocols in terms of safety-critical packet delivery and energy consumption.

  8. Constraint-based local search for container stowage slot planning

    DEFF Research Database (Denmark)

    Pacino, Dario; Jensen, Rune Møller; Bebbington, Tom

    2012-01-01

    -sea vessels. This paper describes the constrained-based local search algorithm used in the second phase of this approach where individual containers are assigned to slots in each bay section. The algorithm can solve this problem in an average of 0.18 seconds per bay, corresponding to a 20 seconds runtime...

  9. Cylindrical spirals in human skeletal muscle.

    Science.gov (United States)

    Carpenter, S; Karpati, G; Robitaille, Y; Melmed, C

    1979-01-01

    Muscle biopsies from two patients revealed that numerous type 2 fibers contained large abnormal areas filled with cylindrical spirals. The cytochemical profile of these cylindrical spirals was sufficiently characteristic that they could be distinguished from tubular aggregates. Their electron microscopic appearance was unmistakable. Their origin and significance are uncertain. The diverse nature of the patients' conditions (cramps and malignancy, and an unusual form of spinocerebellar degeneration) indicate that these abnormal structures are not disease specific.

  10. Wavelet Scattering on the Pitch Spiral

    OpenAIRE

    Lostanlen, Vincent; Mallat, Stéphane

    2016-01-01

    We present a new representation of harmonic sounds that linearizes the dynamics of pitch and spectral envelope, while remaining stable to deformations in the time-frequency plane. It is an instance of the scattering transform, a generic operator which cascades wavelet convolutions and modulus nonlinearities. It is derived from the pitch spiral, in that convolutions are successively performed in time, log-frequency, and octave index. We give a closed-form approximation of spiral scattering coe...

  11. 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)

  12. 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.

  13. SIGNATURES OF LONG-LIVED SPIRAL PATTERNS

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Garcia, Eric E. [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Aptdo. Postal 51 y 216, 72000 Puebla, Pue. (Mexico); Gonzalez-Lopezlira, Rosa A., E-mail: ericmartinez@inaoep.mx, E-mail: martinez@astro.unam.mx, E-mail: r.gonzalez@crya.unam.mx [Centro de Radioastronomia y Astrofisica, UNAM, Campus Morelia, Michoacan, C.P. 58089 (Mexico)

    2013-03-10

    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){sub 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.

  14. 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.

  15. A performance analysis of a hig-speed slotted-ring acces mechanism with dynamically adaptive slot sizes

    NARCIS (Netherlands)

    Pasch, H.L.; Pasch, H.L.; Niemegeers, I.G.M.M.

    1991-01-01

    A network design is proposed in which the number of tokens has been made adaptive, resulting in a network that can be made to behave like both the token ring and the slotted ring, or anything in between (i.e., it performs optimally for any given message length). Results are presented that show how

  16. 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

  17. The Role of Auditory Features Within Slot-Themed Social Casino Games and Online Slot Machine Games.

    Science.gov (United States)

    Bramley, Stephanie; Gainsbury, Sally M

    2015-12-01

    Over the last few years playing social casino games has become a popular entertainment activity. Social casino games are offered via social media platforms and mobile apps and resemble gambling activities. However, social casino games are not classified as gambling as they can be played for free, outcomes may not be determined by chance, and players receive no monetary payouts. Social casino games appear to be somewhat similar to online gambling activities in terms of their visual and auditory features, but to date little research has investigated the cross over between these games. This study examines the auditory features of slot-themed social casino games and online slot machine games using a case study design. An example of each game type was played on three separate occasions during which, the auditory features (i.e., music, speech, sound effects, and the absence of sound) within the games were logged. The online slot-themed game was played in demo mode. This is the first study to provide a qualitative account of the role of auditory features within a slot-themed social casino game and an online slot machine game. Our results found many similarities between how sound is utilised within the two games. Therefore the sounds within these games may serve functions including: setting the scene for gaming, creating an image, demarcating space, interacting with visual features, prompting players to act, communicating achievements to players, providing reinforcement, heightening player emotions and the gaming experience. As a result this may reduce the ability of players to make a clear distinction between these two activities, which may facilitate migration between games.

  18. Some INDRA experiments on SPIRAL

    International Nuclear Information System (INIS)

    Cussol, D.; Orr, N.A.

    1997-01-01

    A panel joining members of INDRA collaboration and physicists off collaboration was gathered to debate the question whether the INDRA detector, designed to study multifragmentation with beams of stable nuclei, could be used also in experiments with beams of exotic nuclei. Four experiments were discussed as well as the implied detector modifications. In the frame of experiments with SISSI the study of the multifragmentation as a function of N/Z of the system should answer questions related to the system stability as a function of N/Z and origin of the particles emitted during the collision. Among the experiments with SPIRAL to study de-excitation of hot nuclei the following topics were examined: nuclear stability as a function of N/Z, α-n competition, emission of neutron-rich particles as a function of N/Z, evolution of emission modes near the shell closure. The de-excitation of the resonant excited states through 2p decay will be studied in the following three channels: 1p-1p sequential decay, un-correlated simultaneous 2p emission and correlated simultaneous 2p emission ( 2 He emission). Such experiments were carried out on 6 Be, 12 O and 14 O. The only first two channels were observed so far. The 16 Ne could be a good candidate to observe the third channel. Finally sub-barrier Coulomb fusion experiments were also discussed. Concerning the modifications to be undertaken on INDRA detector two were obvious: a modification at the level of electronics to make possible time-of-flight measurements with silicon detectors and transformations of ionization chambers in Bragg chambers. Simulation studies are under way to test the pertinence and validity of the solution

  19. Slot Parameter Optimization for Multiband Antenna Performance Improvement Using Intelligent Systems

    Directory of Open Access Journals (Sweden)

    Erdem Demircioglu

    2015-01-01

    Full Text Available This paper discusses bandwidth enhancement for multiband microstrip patch antennas (MMPAs using symmetrical rectangular/square slots etched on the patch and the substrate properties. The slot parameters on MMPA are modeled using soft computing technique of artificial neural networks (ANN. To achieve the best ANN performance, Particle Swarm Optimization (PSO and Differential Evolution (DE are applied with ANN’s conventional training algorithm in optimization of the modeling performance. In this study, the slot parameters are assumed as slot distance to the radiating patch edge, slot width, and length. Bandwidth enhancement is applied to a formerly designed MMPA fed by a microstrip transmission line attached to the center pin of 50 ohm SMA connecter. The simulated antennas are fabricated and measured. Measurement results are utilized for training the artificial intelligence models. The ANN provides 98% model accuracy for rectangular slots and 97% for square slots; however, ANFIS offer 90% accuracy with lack of resonance frequency tracking.

  20. A Compact UWB Band-Pass Filter Using Embedded Circular Slot Structures for Improved Upper Stop-band Performance

    DEFF Research Database (Denmark)

    Shen, Ming; Ren, Jian; Mikkelsen, Jan Hvolgaard

    2016-01-01

    This paper presents an ultra-wideband band-pass filter designed using a slot-line ring resonator and two pairs of embedded circular slot structures. The slot-line ring resonator is used to form the desired UWB passband, and the upper stop-band response is suppressed by embedding the circular slot...

  1. 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

  2. Theory of a Traveling Wave Feed for a Planar Slot Array Antenna

    Science.gov (United States)

    Rengarajan, Sembiam

    2012-01-01

    Planar arrays of waveguide-fed slots have been employed in many radar and remote sensing applications. Such arrays are designed in the standing wave configuration because of high efficiency. Traveling wave arrays can produce greater bandwidth at the expense of efficiency due to power loss in the load or loads. Traveling wave planar slot arrays may be designed with a long feed waveguide consisting of centered-inclined coupling slots. The feed waveguide is terminated in a matched load, and the element spacing in the feed waveguide is chosen to produce a beam squinted from the broadside. The traveling wave planar slot array consists of a long feed waveguide containing resonant-centered inclined coupling slots in the broad wall, coupling power into an array of stacked radiating waveguides orthogonal to it. The radiating waveguides consist of longitudinal offset radiating slots in a standing wave configuration. For the traveling wave feed of a planar slot array, one has to design the tilt angle and length of each coupling slot such that the amplitude and phase of excitation of each radiating waveguide are close to the desired values. The coupling slot spacing is chosen for an appropriate beam squint. Scattering matrix parameters of resonant coupling slots are used in the design process to produce appropriate excitations of radiating waveguides with constraints placed only on amplitudes. Since the radiating slots in each radiating waveguide are designed to produce a certain total admittance, the scattering (S) matrix of each coupling slot is reduced to a 2x2 matrix. Elements of each 2x2 S-matrix and the amount of coupling into the corresponding radiating waveguide are expressed in terms of the element S11. S matrices are converted into transmission (T) matrices, and the T matrices are multiplied to cascade the coupling slots and waveguide sections, starting from the load end and proceeding towards the source. While the use of non-resonant coupling slots may provide an

  3. Induction forming of metal components with slotted susceptors

    Science.gov (United States)

    Matsen, Marc R; Dykstra, William

    2013-02-19

    A laminated tooling apparatus includes a first tooling die, a first susceptor carried by the first tooling die and having at least one straight susceptor portion and at least one angled susceptor portion adjacent to the straight susceptor portion, a first plurality of susceptor slots extending through the at least one angled susceptor portion of the first tooling die, a second tooling die adjacent to the first tooling die, a second susceptor carried by the second tooling die and having at least one straight susceptor portion and at least one angled susceptor portion adjacent to the straight susceptor portion; and a second plurality of susceptor slots extending through the at least one angled susceptor portion of the second tooling die.

  4. Loop-mirror-based slot waveguide refractive index sensor

    Directory of Open Access Journals (Sweden)

    Jun-long Kou

    2012-12-01

    Full Text Available Loop mirror has been widely used in fiber optical devices and systems for it provides a smart way to make use of the fiber birefringence properties and can enhance the sensitivity greatly. On the other hand, slot waveguide is very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper, we propose and analyze a loop-mirror-based slot waveguide (LMSW sensor which can be routinely fabricated in modern high-volume complementary metal-oxide–semiconductor (CMOS process. The finite element method (FEM simulation results show that the birefringence can be as high as 0.8 which is orders of magnitude than that in conventional birefringent fiber loop mirror. High sensitivity up to 6 × 103 nm/RIU (refractive index unit is achieved by this scheme.

  5. An 8-Channel Wavelength MMI Demultiplexer in Slot Waveguide Structures.

    Science.gov (United States)

    Ben Zaken, Bar Baruch; Zanzury, Tal; Malka, Dror

    2016-11-01

    We propose a novel 8-channel wavelength multimode interference (MMI) demultiplexer in slot waveguide structures that operate at 1530 nm, 1535 nm, 1540 nm, 1545 nm, 1550 nm, 1555 nm, 1560 nm, and 1565 nm. Gallium nitride (GaN) surrounded by silicon (Si) was found to be a suitable material for the slot-waveguide structures. The proposed device was designed by seven 1 × 2 MMI couplers, fourteen S-bands, and one input taper. Numerical investigations were carried out on the geometrical parameters using a full vectorial-beam propagation method (FV-BPM). Simulation results show that the proposed device can transmit 8-channel that works in the whole C-band (1530-1565 nm) with low crosstalk (-19.97--13.77 dB) and bandwidth (1.8-3.6 nm). Thus, the device can be very useful in optical networking systems that work on dense wavelength division multiplexing (DWDM) technology.

  6. Athermal operation of multi-section slotted tunable lasers.

    Science.gov (United States)

    Wallace, M J; O'Reilly Meehan, R; Enright, R; Bello, F; McCloskey, D; Barabadi, B; Wang, E N; Donegan, J F

    2017-06-26

    Two distinct athermal bias current procedures based on thermal tuning are demonstrated for a low-cost, monotlithic, three section slotted single mode laser, achieving mode-hop free wavelength stability of ± 0.04 nm / 5 GHz over a temperature range of 8-47 °C. This is the first time that athermal performance has been demonstrated for a three-section slotted laser with simple fabrication, and is well within the 50 GHz grid spacing specified for DWDM systems. This performance is similar to experiments on more complex DS-DBR lasers, indicating that strong athermal performance can be achieved using our lower-cost three section devices. An analytical model and thermoreflectance measurements provide further insight into the operation of multi-section lasers and lay the foundation for an accurate predictive tool for optimising such devices for athermal operation.

  7. Numerical and physical model study of a vertical slot fishway

    Directory of Open Access Journals (Sweden)

    Bombač Martin

    2014-06-01

    Full Text Available This paper presents the results of an experimental and numerical study of a vertical slot fishway (VSF. A 2-D depth-averaged shallow water numerical model PCFLOW2D coupled with three different turbulent models (constant eddy viscosity, Smagorinsky and k - ε was used. A detailed analysis of numerical parameters needed for a correct simulation of the phenomenon was carried out. Besides the velocity field, attention was paid to important hydraulic parameters such as maximum velocity in the slot region and energy dissipation rate ε in order to evaluate the performance of VSF. A scaled physical hydraulic model was built to ensure reliable experimental data for the validation of the numerical model. Simulations of variant configurations of VSF showed that even small changes in geometry can produce more fishfriendly flow characteristics in pools. The present study indicates that the PCFLOW2D program is an appropriate tool to meet the main demands of the VSF design.

  8. Analysis of magnetic abrasive finishing with slotted magnetic pole

    Science.gov (United States)

    Jayswal, S. C.; Jain, V. K.; Dixit, P. M.

    2004-06-01

    Magnetic Abrasive Finishing (MAF) is relatively a new finishing process among the advanced finishing processes in which the workpiece is kept in the magnetic field created by two poles of an electromagnet. The working gap between the workpiece and the magnet is filled with magnetic abrasive particles. A flexible magnetic abrasive brush is formed, acting as a multipoint cutting tool, due to the effect of magnetic field in the working gap. This process is capable of producing the surface finish of nanometer range. Most of the researchers have been using the electromagnet having a slot in it to improve the performance of the process but hardly any information is available about its effect on the process performance. This paper deals with the effect of a slot made in the electromagnet on the forces and surface quality during MAF. An experimental set-up is designed and fabricated for the measurement of the magnetic field distribution in the working gap. The magnetic field is simulated using a finite element model of the process. The magnetic field is also measured experimentally to validate the theoretical results. It indicates a good agreement between the experimental results and simulated values. The finite element method is further used for the evaluation of the magnetic force and surface quality during MAF. To our surprise it is found that the force under the slot is negative, even then process performance is improved. MAF process removes a very small amount of material by indentation and rotation of the magnetic abrasive particles in the circular tracks. Due to rotation of the magnetic abrasive flexible brush, grooves are formed on the workpiece surface which decides the surface profile after MAF. Surface quality is determined on the basis of the surface profile achieved by equating the volume of groove produced. These results show an improvement in finishing rate while using a slotted pole surface.

  9. On the Carter's Factor Calculation for Slotted Electric Machines

    Directory of Open Access Journals (Sweden)

    VIOREL, I. A.

    2007-11-01

    Full Text Available The air-gap flux density in a single side slotted unsaturated machine is computed via two dimensions finite element method (2D-FEM and via some analytical approximations. The Carter's factor values are calculated using different equations and a comparison between the obtained results is presented, allowing for pertinent conclusions concerning the flux density analytical estimation or the Carter's factor calculation.

  10. Application of fractional slot concentrated windings to synchronous reluctance machines.

    OpenAIRE

    Spargo, C.M.; Mecrow, B.C.; Widmer, J.D.

    2013-01-01

    Due to the advancement of electric vehicles, the desire for high torque density electric motors for traction applications is steadily increasing. It is advantageous to design such a motor with little or no rare earth permanent magnet (PM) material due to the associated environmental, political and economic challenges with its extraction and processing. This paper explores a novel synchronous reluctance machine (RSM), with fractional slot concentrated windings (cRSM) as an alternative to PM, i...

  11. Cutting Forces Prediction in the Dry Slotting of Aluminium Stacks

    OpenAIRE

    SALGUERO, Jorge; CALAMAZ, Madalina; BATISTA, Moises; GIROT, Franck; MARCOS, Mariano

    2014-01-01

    International audience; Cutting forces are one of the inherent phenomena and a very significant indicator of themetal cutting process. The work presented in this paper is an investigation of the prediction of these parameters in slotting processes of UNS A92024-T3 (Al-Cu) stacks. So, cutting speed (V) and feed per tooth (fz) based parametric models, for experimental components of cutting force, F(fz,V) have been proposed. These models have been developed from the individual models extracted f...

  12. broadband, low sidelobe, zero height, slotted circular disk antenna

    African Journals Online (AJOL)

    of argument rr where J? = jwµ.(slot of the antenna can be obtained by substituting 'Tr', hack into the field equations. The results are given hy the ...

  13. Period Estimation in Astronomical Time Series Using Slotted Correntropy

    OpenAIRE

    Huijse, Pablo; Estévez, Pablo A.; Zegers, Pablo; Príncipe, José; Protopapas, Pavlos

    2011-01-01

    In this letter, we propose a method for period estimation in light curves from periodic variable stars using correntropy. Light curves are astronomical time series of stellar brightness over time, and are characterized as being noisy and unevenly sampled. We propose to use slotted time lags in order to estimate correntropy directly from irregularly sampled time series. A new information theoretic metric is proposed for discriminating among the peaks of the correntropy spectral density. The sl...

  14. Applicative Characteristics of a New Zirconia Bracket with Multiple Slots

    Directory of Open Access Journals (Sweden)

    Koutaro Maki

    2016-01-01

    Full Text Available We have developed a new orthodontic bracket with three slots with lubricative properties on the working surfaces and proposed a new orthodontic treatment system employing 0.012−0.014-inch Ni-Ti arch wires. We recruited 54 patients, of which 27 received treatment with the new zirconia bracket with multiple slots system (M group, and the others received treatment with standard edge-wise appliances (control group [C group]. We compared the (1 tooth movement rate at the early stage of leveling; (2 changes in the dental arch morphology before and after leveling; and (3 pain caused by orthodontic treatment. Student’s t-test was used in all assessments. The tooth movement rate in the maxillomandibular dentition was higher in the M group. The basal arch width, anterior length, and the intercanine width in the maxillary dentition were not significantly different in the two groups; however, the intercanine width in the mandibular dentition was higher in the C group. In assessments of treatment-related pain, the visual analogue pain score was 56.0 mm and 22.6 mm in the C and M groups, respectively. A new zirconia bracket with multiple slots system provided better outcomes with respect to tooth movement rate, treatment period, and postoperative pain, thus indicating its effectiveness over conventional orthodontic systems.

  15. 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)

  16. Flexural and Thermal Properties of Novel Energy Conservation Slotted Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    Gao Ma

    2016-01-01

    Full Text Available Conventional solid reinforced concrete (RC beams were modified to slotted beams for consideration as thermal insulation structural components. The slotted beam consisted of an outer and an inner beam, respectively, with a slot located near the middle of the beam along its width direction for filling thermal insulation material. Flexural and thermal behavior of the slotted beams were investigated. Three RC reference solid beams and six slotted beams were fabricated and tested under four-point bending tests. The test results indicated that the failure mode of both slotted beams and the solid beams was flexural failure. However, the damage process of the slotted beams was different from that of the solid beams at the final loading stage. The moment curvature analysis indicated that the tensile reinforcement ratio of the outer and inner beams had an important effect on the flexural behavior, especially the ductility of the slotted beams. Thermal study indicated that the heat transfer coefficient of the slotted beam was greatly reduced and the thermal inertia factor increased a lot, compared with the solid beam. In addition, FE simulation results showed that a new frame structure using slotted beams exhibited obvious and attractive thermal insulation property.

  17. Graphite target for the spiral project

    Energy Technology Data Exchange (ETDEWEB)

    Putaux, J.C.; Ducourtieux, M.; Ferro, A.; Foury, P.; Kotfila, L.; Mueller, A.C.; Obert, J.; Pauwels, N.; Potier, J.C.; Proust, J. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Bertrand, P. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Loiselet, M. [Universite Catholique de Louvain, Louvain-La-Neuve (Belgium)] [and others

    1996-12-31

    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). 5 refs.

  18. Photometry and mass modeling of spiral galaxies

    International Nuclear Information System (INIS)

    Kent, S.

    1987-01-01

    Recent estimates of the relative contributions of dark and luminous matter to the mass of spiral galaxies are reviewed. In these studies, the galactic mass distribution is modeled on the basis of photometric and kinematic observational data. The accuracy of current photometry is discussed; the three-dimensional structure of spiral galaxies and the techniques used in bulge-disk decomposition are examined; and mass models incorporating rotation curves are presented. The disk mass/luminosity ratios in the red band (corrected for internal extinction) are found to range from 1.6 to 3.2, with no particular radius at which dark matter dominates. 20 references

  19. Investigation of slot discharge on a 239 MVA hydro generator stator winding

    Energy Technology Data Exchange (ETDEWEB)

    Li, S.; Hong, W. [BC Hydro and Power Authority, Vancouver, BC (Canada)

    2009-07-01

    This paper discussed a slot discharge investigation conducted on a 239 MVA generator stator winding. The generator in which the winding was located had experienced core split distortion, stator winding phase-to-phase failures, winding failures during Hipot testing, and high partial discharge (PD) activity. The results of on-line PD testing data were evaluated. The stator winding was subjected to visual inspections, bar dissections, and failure mechanism analyses. Eleven winding bars were removed from the stator slots in order to assess groundwall insulation conditions and identify the cause of the slot discharge activity. It was determined that the root cause of the slot discharge was a loose, non-uniform bar in the slot. The vibrating bar caused the semi-conductive coating to wear out and degraded the armour tape. Results of the study demonstrated the importance of on-line PD monitoring for detecting slot PD activity. 4 refs., 3 tabs., 11 figs.

  20. 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)

  1. 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

  2. Geometric studies on variable radius spiral cone-beam scanning

    International Nuclear Information System (INIS)

    Ye Yangbo; Zhu Jiehua; Wang Ge

    2004-01-01

    The goal is to perform geometric studies on cone-beam CT scanning along a three-dimensional (3D) spiral of variable radius. First, the background for variable radius spiral cone-beam scanning is given in the context of electron-beam CT/micro-CT. Then, necessary and sufficient conditions are proved for existence and uniqueness of PI lines inside the variable radius 3D spiral. These results are necessary steps toward exact cone-beam reconstruction from a 3D spiral scan of variable radius, adapting Katsevich's formula for the standard helical cone-beam scanning. It is shown in the paper that when the longitudinally projected planar spiral is not always convex toward the origin, the PI line may not be unique in the envelope defined by the tangents of the spiral. This situation can be avoided by using planar spirals whose curvatures are always positive. Using such a spiral, a longitudinally homogeneous region inside the corresponding 3D spiral is constructed in which any point is passed by one and only one PI line, provided the angle ω between planar spiral's tangent and radius is bounded by vertical bar ω-90 deg. vertical bar ≤ε for some positive ε≤32.48 deg. If the radius varies monotonically, this region is larger and one may allow ε≤51.85 deg. Examples for 3D spirals based on logarithmic and Archimedean spirals are given. The corresponding generalized Tam-Danielsson detection windows are also formulated

  3. 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...

  4. The Distribution of Mass in Spiral Galaxies.

    NARCIS (Netherlands)

    Swaters, Rob; Andersen, David; Bershady, Matthew; Verheijen, Marc

    2002-01-01

    Little is known about the content and distribution of dark matter in spiral galaxies. Mass modeling of any rotation curve can yield an alarming range of results - from entirely halo-dominated, centrally- concentrated dark distributions, to disk-dominated inner potentials with shallow, low density

  5. The surface brightness of spiral galaxies

    International Nuclear Information System (INIS)

    Phillipps, S.; Disney, M.

    1983-01-01

    Correlations between optical surface brightness and the radio properties of spiral galaxies are investigated. It is found that galaxies with high surface brightness are more likely to be strong continuum radio sources and that galaxies with low surface brightness have high 21-cm line emission. (author)

  6. 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.

  7. 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 ...

  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. 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…

  10. 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.

  11. 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

  12. SPIRAL2 at GANIL: Status and Perspectives

    Science.gov (United States)

    Gales, S.

    2008-05-01

    To pursue the investigation of a new territory of nuclei with extreme N/Z called ``terra incognita'' several projects, all aiming at the increase by several orders of magnitude of the RIB intensities are now under discussions worldwide. In Europe, two major new projects have been approved recently FAIRatGSI using the so-called ``in-flight'' method and SPIRAL2atGANIL, based on the ISOL method. Both projects were selected in the European Strategic Roadmap For research Infrastructures (ESFRI). The main goal of SPIRAL2 is clearly to extend our knowledge of the limit of existence and the structure of nuclei deeply in the medium and heavy mass region (A = 60 to 140) which is to day an almost unexplored continent. SPIRAL 2 is based on a high power, CW, superconducting driver LINAC, delivering 5 mA of deuteron beams at 40 MeV (200 KW) directed on a C converter+ Uranium target and producing therefore more 1013 fissions/s. The expected radioactive beams intensities for exotic species in the mass range from A = 60 to A = 140, of the order of 106 to 1010 pps will surpass by two order of magnitude any existing facilities in the world. These unstable atoms will be available at energies between few KeV/n to 15 MeV/n. The same driver will accelerate high intensity (100 μA to 1 mA), heavier ions up to Ar at 14 MeV/n producing also proton rich exotic nuclei. In applied areas SPIRAL2 is considered as a powerful variable energy neutron source, a must to study the impact of nuclear fission and fusion on materials. The intensities of these unstable species are excellent opportunities for new tracers and diagnostics either for solid state, material or for radiobiological science and medicine. The ``Go'' decision has been taken in May 2005. The investments and personnel costs amount to 190 M€, for the construction period 2006-2012. Construction of the SPIRAL2 facility is shared by ten French laboratories and a network of international partners. Under the 7FP program of European Union

  13. Pengaruh Slot Rugby Ball Terhadap Antena Mikrostrip Sehingga Dapat Bekerja Pada Ultra Wideband (UWB)

    OpenAIRE

    M. Fauzan Edy Purnomo, ST., MT., Prilla Ayu Wendaria., Rudy Yuwono, ST., M.Sc

    2013-01-01

    Penelitian ini membahas tentang pengaruh slot rugby ball pada antena mikrostrip annular ring sehingga dapat bekerja pada ultra wideband (UWB). Antena mikrostrip annular ring dengan slot rugby ball ini dirancang dengan menggunakan feed line sebagai metode pencatuannya. Dimensi antena diperoleh melalui perhitungan dan optimasi serta dilakukan simulasi dengan menggunakan software HFSS AnsoftTM versi 13. Hasil simulasi antena mikrostrip annular ring dengan slot rugby ball menunjukkan frekuensi ...

  14. 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.

  15. GANIL-SPIRAL2: A new era

    Science.gov (United States)

    Gales, Sydney

    2011-05-01

    GANIL presently offers unique opportunities in nuclear physics and many other fields that arise from not only the provision of low-energy stable beams, fragmentation beams and re-accelerated radioactive species, but also from the availability of a wide range of state-of-the-art spectrometers and instrumentation. A few examples of recent highlights are discussed in the present paper. With the construction of SPIRAL2 over the next few years, GANIL is in a good position to retain its world-leading capability. As selected by the ESFRI committee, the next generation of ISOL facility in Europe is represented by the SPIRAL2 project to be built at GANIL (Caen, France). SPIRAL 2 is based on a high power, CW, superconducting LINAC, delivering 5 mA of deuteron beams at 40 MeV (200 KW) directed on a C converter+ Uranium target and producing therefore more than 1013 fissions/s. The expected radioactive beam intensities in the mass range from A = 60 to A = 140, will surpass by two orders of magnitude any existing facilities in the world. These unstable atoms will be available at energies between few KeV/n to 15 MeV/n. The same driver will accelerate high intensity (100 μA to 1 mA), heavier ions (Ar up to Xe) at maximum energy of 14 MeV/n. Under the 7FP program of European Union called *Preparatory phase*, the SPIRAL2 project has been granted a budget of about 4M€ to build up an international consortium around this new venture. The status of the construction of SPIRAL2 accelerator and associated physics instruments in collaboration with EU and International partners will be presented.

  16. G-Tunnel pressurized slot-testing preparations; Yucca Mountain Site Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, R.M.; Sifre-Soto, C. [Sandia National Labs., Albuquerque, NM (United States); Mann, K.L.; Bellman, R.A. Jr.; Luker, S. [Science Applications International Corp., Las Vegas, NV (United States); Dodds, D.J. [North Pacific Research, Portland, OR (United States)

    1992-04-01

    Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National laboratories elected to conduct a development program on pressurized slot testing and featured (1) development of an improved method to cut slots using a chain saw with diamond-tipped cutters, (2) measurements useful for determining in situ stresses normal to slots, (3) measurements applicable for determining the in situ modulus of deformation parallel to a drift surface, and (4) evaluations of the potentials of pressurized slot strength testing. This report describes the preparations leading to the measurements and evaluations.

  17. Dark Flow, Depression and Multiline Slot Machine Play.

    Science.gov (United States)

    Dixon, Mike J; Stange, Madison; Larche, Chanel J; Graydon, Candice; Fugelsang, Jonathan A; Harrigan, Kevin A

    2018-03-01

    Multiline slot machines allow for a unique outcome type referred to as a loss disguised as a win (LDW). An LDW occurs when a player gains credits on a spin, but fewer credits than their original wager (e.g. 15-cent gain on a 20-cent wager). These outcomes alter the gambler's play experience by providing frequent, albeit smaller, credit gains throughout a playing session that are in fact net losses. Despite this negative overall value, research has shown that players physiologically respond to LDWs as if they are wins, not losses. These outcomes also create a "smoother" experience for the player that seems to promote a highly absorbing, flow-like state that we have called "dark flow". Past research has indicated that there may be a relationship between problem gambling status and dark flow, as well as between dark flow, depression, and gambling expectancies. In this study, we sought to further understand these relationships, while examining the influence of LDWs on game preference in the context of single versus multiline slots play. We used a realistic slot machine simulator equipped with a force transducer to measure how hard players pressed the spin button following different outcomes. This measure of arousal showed that LDWs were treated similarly to small wins. Participants overwhelmingly preferred the multiline game and experienced more positive affect while playing it, compared to the single-line game. Problem gambling severity index scores were related to dark flow in both games, but this relationship was stronger for the multiline game. Additionally, depression symptomatology and dark flow were strongly correlated in the multiline game, with significant relationships between depression and gambling expectancy, and gambling expectancy and dark flow ratings also emerging.

  18. Different optical properties in different periodic slot cavity geometrical morphologies

    Science.gov (United States)

    Zhou, Jing; Shen, Meng; Du, Lan; Deng, Caisong; Ni, Haibin; Wang, Ming

    2016-09-01

    In this paper, optical properties of two-dimensional periodic annular slot cavity arrays in hexagonal close-packing on a silica substrate are theoretically characterized by finite difference time domain (FDTD) simulation method. By simulating reflectance spectra, electric field distribution, and charge distribution, we confirm that multiple cylindrical surface plasmon resonances can be excited in annular inclined slot cavities by linearly polarized light, in which the four reflectance dips are attributed to Fabry-Perot cavity resonances in the coaxial cavity. A coaxial waveguide mode TE11 will exist in these annular cavities, and the wavelengths of these reflectance dips are effectively tailored by changing the geometrical pattern of slot cavity and the dielectric materials filled in the cavities. These resonant wavelengths are localized in annular cavities with large electric field enhancement and dissipate gradually due to metal loss. The formation of an absorption peak can be explained from the aspect of phase matching conditions. We observed that the proposed structure can be tuned over the broad spectral range of 600-4000 nm by changing the outer and inner radii of the annular gaps, gap surface topography. Meanwhile, different lengths of the cavity may cause the shift of resonance dips. Also, we study the field enhancement at different vertical locations of the slit. In addition, dielectric materials filling in the annular gaps will result in a shift of the resonance wavelengths, which make the annular cavities good candidates for refractive index sensors. The refractive index sensitivity of annular cavities can also be tuned by the geometry size and the media around the cavity. Annular cavities with novel applications can be implied as surface enhanced Raman spectra substrates, refractive index sensors, nano-lasers, and optical trappers. Project supported by the National Natural Science Foundation of China (Grant No. 61178044), the Natural Science Foundation

  19. The Calibration of the Slotted Section for Precision Microwave Measurements

    Science.gov (United States)

    1952-03-01

    Ghapy jil, p.* 1, 2« it *i SMH •t~ . vSp"i«,-.5v; -* \\T:T-’ •"^cr gcg^ CCa ^-igto-’^-.’ ü;:sg: S-^Sc^^^^^^ggjiiiMl "" V; «1 --. ,JM~~^^:^ 3...V’ ’-•.’""’"A’v^ s-1 sal HI le. Place a very smooth flat me;tal;ylate at. „the. end of the «slotted sec- tion" (including any adaptors, etc

  20. Constraint-based local search for container stowage slot planning

    DEFF Research Database (Denmark)

    Pacino, Dario; Jensen, Rune Møller; Bebbington, Tom

    2012-01-01

    Due to the economical importance of stowage planning, there recently has been an increasing interest in developing optimization algorithms for this problem. We have developed 2-phase approach that in most cases can generate near optimal stowage plans within a few hundred seconds for large deep-sea...... vessels. This paper describes the constrained-based local search algorithm used in the second phase of this approach where individual containers are assigned to slots in each bay section. The algorithm can solve this problem in an average of 0.18 seconds per bay, corresponding to a 20 seconds runtime...

  1. Spiral analysis-improved clinical utility with center detection.

    Science.gov (United States)

    Wang, Hongzhi; Yu, Qiping; Kurtis, Mónica M; Floyd, Alicia G; Smith, Whitney A; Pullman, Seth L

    2008-06-30

    Spiral analysis is a computerized method that measures human motor performance from handwritten Archimedean spirals. It quantifies normal motor activity, and detects early disease as well as dysfunction in patients with movement disorders. The clinical utility of spiral analysis is based on kinematic and dynamic indices derived from the original spiral trace, which must be detected and transformed into mathematical expressions with great precision. Accurately determining the center of the spiral and reducing spurious low frequency noise caused by center selection error is important to the analysis. Handwritten spirals do not all start at the same point, even when marked on paper, and drawing artifacts are not easily filtered without distortion of the spiral data and corruption of the performance indices. In this report, we describe a method for detecting the optimal spiral center and reducing the unwanted drawing artifacts. To demonstrate overall improvement to spiral analysis, we study the impact of the optimal spiral center detection in different frequency domains separately and find that it notably improves the clinical spiral measurement accuracy in low frequency domains.

  2. Ultra-Wideband Printed Slot Radiators with Controllable Frequency Characteristics

    Directory of Open Access Journals (Sweden)

    S. L. Chernyshev

    2015-01-01

    Full Text Available We have studied the possibility of creating ultra-wideband (UWB antennas with controlled frequency response of matching based on the printed slot antenna Vivaldi by introducing controlled resonators directly into the structure of the radiator. In the area of irregular slotline there are printed switched resonators with variable capacitance (varactor model, which allow tuning the frequency characteristics for each state of switching cavities, providing bandpass and band-barrage properties of the antenna. The investigation of reconfigurable printed resonators in the system of reconfigurable resonators of a bandpass filter is conducted. The paper considers filter to provide restructuring in the band (3-9 GHz. Electrodynamic simulation of the device was carried out in the time domain using a finite integration method. A bandstop reconfigurable filter is also investigated. The filter located on the substrate opposite the slit is based on tunable L-shaped resonator that has one end connected to the short-circuitor through the board metallization; the other end remains open and is brought into the region of interaction with the slotline. Such filter provides an effective narrow-band suppression and can be easily tuned to the desired frequency channel. The combination of these two types of filters allows you to create a controlled print Vivaldi slot antenna with combined properties. The paper investigates parameters of the scattering and radiation pattern of the antenna in different modes.

  3. An 8-Channel Wavelength MMI Demultiplexer in Slot Waveguide Structures

    Directory of Open Access Journals (Sweden)

    Bar Baruch Ben Zaken

    2016-11-01

    Full Text Available We propose a novel 8-channel wavelength multimode interference (MMI demultiplexer in slot waveguide structures that operate at 1530 nm, 1535 nm, 1540 nm, 1545 nm, 1550 nm, 1555 nm, 1560 nm, and 1565 nm. Gallium nitride (GaN surrounded by silicon (Si was found to be a suitable material for the slot-waveguide structures. The proposed device was designed by seven 1 × 2 MMI couplers, fourteen S-bands, and one input taper. Numerical investigations were carried out on the geometrical parameters using a full vectorial-beam propagation method (FV-BPM. Simulation results show that the proposed device can transmit 8-channel that works in the whole C-band (1530–1565 nm with low crosstalk (−19.97–−13.77 dB and bandwidth (1.8–3.6 nm. Thus, the device can be very useful in optical networking systems that work on dense wavelength division multiplexing (DWDM technology.

  4. Revisiting Street Intersections Using Slot-Based Systems.

    Directory of Open Access Journals (Sweden)

    Remi Tachet

    Full Text Available Since their appearance at the end of the 19th century, traffic lights have been the primary mode of granting access to road intersections. Today, this centuries-old technology is challenged by advances in intelligent transportation, which are opening the way to new solutions built upon slot-based systems similar to those commonly used in aerial traffic: what we call Slot-based Intersections (SIs. Despite simulation-based evidence of the potential benefits of SIs, a comprehensive, analytical framework to compare their relative performance with traffic lights is still lacking. Here, we develop such a framework. We approach the problem in a novel way, by generalizing classical queuing theory. Having defined safety conditions, we characterize capacity and delay of SIs. In the 2-road crossing configuration, we provide a capacity-optimal SI management system. For arbitrary intersection configurations, near-optimal solutions are developed. Results theoretically show that transitioning from a traffic light system to SI has the potential of doubling capacity and significantly reducing delays. This suggests a reduction of non-linear dynamics induced by intersection bottlenecks, with positive impact on the road network. Such findings can provide transportation engineers and planners with crucial insights as they prepare to manage the transition towards a more intelligent transportation infrastructure in cities.

  5. Ion-implantation and analysis for doped silicon slot waveguides

    Directory of Open Access Journals (Sweden)

    McCallum J. C.

    2012-10-01

    Full Text Available We have utilised ion implantation to fabricate silicon nanocrystal sensitised erbium-doped slot waveguide structures in a Si/SiO2/Si layered configuration and photoluminescence (PL and Rutherford backscattering spectrometry (RBS to analyse these structures. Slot waveguide structures in which light is confined to a nanometre-scale low-index region between two high-index regions potentially offer significant advantages for realisation of electrically-pumped Si devices with optical gain and possibly quantum optical devices. We are currently investigating an alternative pathway in which high quality thermal oxides are grown on silicon and ion implantation is used to introduce the Er and Si-ncs into the SiO2 layer. This approach provides considerable control over the Er and Si-nc concentrations and depth profiles which is important for exploring the available parameter space and developing optimised structures. RBS is well-suited to compositional analysis of these layered structures. To improve the depth sensitivity we have used a 1 MeV α beam and results indicate that a layered silicon-Er:SiO2/silicon structure has been fabricated as desired. In this paper structural results will be compared to Er photoluminescence profiles for samples processed under a range of conditions.

  6. Fast spiral-scan atomic force microscopy

    International Nuclear Information System (INIS)

    Mahmood, I A; Reza Moheimani, S O

    2009-01-01

    In this paper, we describe a new scanning technique for fast atomic force microscopy. In this method, the sample is scanned in a spiral pattern instead of the well established raster pattern. A spiral scan can be produced by applying single frequency cosine and sine signals with slowly varying amplitudes to the x-axis and y-axis of an atomic force microscope (AFM) scanner respectively. The use of the single tone input signals allows the scanner to move at high speeds without exciting the mechanical resonance of the device and with relatively small control efforts. Experimental results obtained by implementing this technique on a commercial AFM indicate that high-quality images can be generated at scan frequencies well beyond the raster scans.

  7. 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.

  8. Wind tunnel tests of the GA(W)-2 airfoil with 20% aileron, 25% slotted flap, 30% Fowler flap and 10% slot-lip spoiler

    Science.gov (United States)

    Wentz, W. H., Jr.

    1977-01-01

    Two dimensional wind tunnel tests were conducted for the GA(W)-2 airfoil section with: 20% aileron, 25% slotted flap; 30% Fowler flap, and 10% slot-lip spoiler. All tests were conducted at a Reynolds number of 2,200,000 and a Mach Number of 0.13. In addition to force measurements, tuft studies were conducted for the slotted and Fowler flap configurations. Aileron and spoiler hinge moments were obtained by integration of surface pressure measurements. Tests results show that a value of 3.82 was obtained with 30% Fowler flap. Aileron control effectiveness and hinge moments were similar to other airfoils. The slot-lip spoiler provided powerful, positive roll control at all flap settings.

  9. 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

  10. Dark and visible matter in spiral galaxies

    International Nuclear Information System (INIS)

    Persic, M.; Salucci, P.; Durham Univ.

    1988-01-01

    Exploiting relevant information from the profiles of rotation curves, we calculate the dark-to-luminous mass ratio within the disc size for a sample of 43 spiral galaxies. The values we find, while proving the ubiquitous presence of dark matter, vary with luminosity. Faint and bright galaxies are found to be respectively halo- and disc-dominated in the disc regions. The luminosity sequence turns out to be a dark-to-luminous sequence. (author)

  11. 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)

  12. 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.

  13. Bead beavior in a non-continues slot die coating regime

    NARCIS (Netherlands)

    Langen, A.; Senes, A.; Vries, I. de; Groen, P.

    2015-01-01

    Sheet-to-sheet slot die coating is a crucial intermediate technique to bring organic and large area electronics (e.g. OLED and Flexible OPV) towards mass roll-to-roll productions. The coating on substrate has to be uniform within nanometers. Additional settings are added to the slot die coater for a

  14. Tuning ZOR in ENZ waveguide using a single longitudinal slot and equivalent circuit parameter extraction

    DEFF Research Database (Denmark)

    Vojnovic, Nebojsa; Jokanovic, Branka; Mitrovic, Miranda

    2014-01-01

    In this paper, the effects of placing a longitudinal slot in the channel region of a rectangular waveguide ENZ structure, are analyzed. A following investigation showed that changing the length of this slot can be employed to achieve tuning of only the tunneling frequency. Maximum resonant freque...

  15. 14 CFR 93.218 - Slots for transborder service to and from Canada.

    Science.gov (United States)

    2010-01-01

    ... Canada. 93.218 Section 93.218 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... service to and from Canada. (a) Except as otherwise provided in this subpart, international slots...'Hare in the Winter season. (c) Any modification to the slot base by the Government of Canada or the...

  16. Hydrodynamic Performance of a Dual-Slotted Circulation Control Wing of Low-Aspect Ratio

    Science.gov (United States)

    2006-12-01

    Pressure pv Vapor pressure of water q Dynamic pressure, ρ(Uup)2/2 Re Reynolds number, cUup/ν rs Distance from the center of the spinning disk for LDV...the propulsor . For these results, the flow is defined as the total amount of the flow from the slots with the flow from each slot as half of the total

  17. Comparative evaluation of slot versus dovetail design in class III composite restorations in primary anterior teeth

    Directory of Open Access Journals (Sweden)

    Arun Rathnam

    2010-01-01

    It was concluded from the results that the both slot and dovetail types of cavity preparations were equally effacious when clinically reviewed for a period of 12 months. Hence the use of slot type of cavity preparation with reduced loss of the tooth structure is indicated for class III cavities in primary anterior teeth.

  18. 14 CFR 93.226 - Allocation of slots in low-demand periods.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Allocation of slots in low-demand periods. 93.226 Section 93.226 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... low-demand periods. (a) If there are available slots in the following time periods and there are no...

  19. 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.

  20. Testing an Incentive-Sensitisation Approach to Understanding Problem Slot-Machine Gambling Using an Online Slot-Machine Simulation.

    Science.gov (United States)

    Davey, Belinda; Cummins, Robert

    2017-10-16

    This study aims to test the application of the incentive-sensitisation theory to slot-machine gambling behaviour. The theory posits that for problem gamblers (PGs), gambling strengthens the response of motivational pathways in the mid-brain to gambling cues, eliciting strong wanting, independent of liking. Non-problem gamblers (NPGs) experience weaker changes to motivational pathways so liking and wanting remain associated. Hence, it is predicted that wanting to gamble will be greater than liking for PGs but there will be no difference for NPGs; wanting will be greater for PGs than for NPGs; and, wanting but not liking will predict whether PGs continue gambling, whereas both will predict this for NPGs. During gambling on an online simulated slot-machine, 39 PGs and 87 NPGs rated 'liking' and 'wanting'. Participants played at least 3 blocks of 10-20 spins, and then had the option of playing up to 4 additional blocks; to continue playing they had to complete an effortful task, so that 'number of blocks played' acted as an additional indirect measure of wanting. Results supported hypotheses except on the indirect measure of wanting (the number of blocks played).

  1. Analysis of Coupling Effectiveness on Concealed Signal Cable Slot with Different Shapes

    Directory of Open Access Journals (Sweden)

    Chun-Jiang Shuai

    2014-01-01

    Full Text Available It is important to study the shielding effectiveness to reduce the electromagnetic interference and to protect electronic components. Taking the concealed signal cable which is set in shielding shell as the research object. The influence of different slot shapes on shielding effectiveness was analyzed by applying the mixed methods (Quadric FE-BEM. The results show that the coupling capacitance of a trapezoidal slot is the biggest, the one of rectangular slot is medium, and the one of a taper slot is the smallest for shielding pair cable, but their change trend are almost the same. In addition, with the various slot shapes width increasing, shielding pair cable coupling capacitance is little changed. The study is instructive for more effective to defense EMI and will improve the agricultural concealed shielding cable electromagnetic compatibility.

  2. Azimuthal instabilities and mixing characteristics of a small aspect ratio slot jet

    International Nuclear Information System (INIS)

    Gutmark, E.; Schadow, K.C.

    1987-01-01

    Two types of small aspect ratio slot jets were investigated. An orifice slot jet with a 3:1 aspect ratio was shown to have features similar to an elliptical jet with a well-designed contraction. A large spreading rate and highly turbulent mixing can be obtained using this orifice nozzle, which is advantageous for many practical applications. By adding a conical contraction to the slot jet (tapered slot jet) the characteristics were totally altered. The intersection between the contraction and the slot surface produced three dimensional vortical structures. These structures acted with the high modes of azimuthal instabilities, typical to this noncircular configuration, to produce highly efficient mixing in both the outside and inside segments of the jet. 10 references

  3. FEM Analysis of Brushless DC Servomotor with Fractional Number of Slots per Pole

    Directory of Open Access Journals (Sweden)

    BALUTA, G.

    2014-02-01

    Full Text Available The authors present in this paper the analysis with Finite Element Method (FEM of the magnetic circuit for a Brushless DC servomotor with fractional number of slots/pole (9 slots and 10 poles. For this purpose, FEMM 4.2 software package was used for the analysis. To obtain the waveforms of Back-ElectroMotive Forces (BEMFs, electromagnetic and cogging torque for servomotor a program in LUA scripting language (integrated into interactive shell of FEMM4.2 has been created. A comparation with a structure with integer number of slots/pole (18 slots and 6 poles was also realized. The analysis results prove that the structure chosen is an optimal solution: sinusoidal waveforms of BEMFs, improved electromagnetic torque and reduced cogging torque. Therefore, the operating characteristics of the servomotor with 9/10 slots/poles manufactured by Sistem Euroteh Company and included in an integrated electrical drives system are presented in this paper.

  4. Micro-Slotting Technique for Reliable Measurement of Sub-Surface Residual Stress in Ti-6Al-4V (Preprint)

    Science.gov (United States)

    2017-09-28

    measuring local residual stresses in a variety of materials. The micro-slotting method relies on a Scanning Electron Microscope – Focused Ion Beam (SEM...residual stresses in a variety of materials. The micro-slotting method relies on a Scanning Electron Microscope – Focused Ion Beam (SEM-FIB) system for...between milled slots for ə% error in the stress calculations. Residual stress measurements The three series of micro-slotting measurements show

  5. Low Average Sidelobe Slot Array Antennas for Radiometer Applications

    Science.gov (United States)

    Rengarajan, Sembiam; Zawardzki, Mark S.; Hodges, Richard E.

    2012-01-01

    In radiometer applications, it is required to design antennas that meet low average sidelobe levels and low average return loss over a specified frequency bandwidth. It is a challenge to meet such specifications over a frequency range when one uses resonant elements such as waveguide feed slots. In addition to their inherent narrow frequency band performance, the problem is exacerbated due to modeling errors and manufacturing tolerances. There was a need to develop a design methodology to solve the problem. An iterative design procedure was developed by starting with an array architecture, lattice spacing, aperture distribution, waveguide dimensions, etc. The array was designed using Elliott s technique with appropriate values of the total slot conductance in each radiating waveguide, and the total resistance in each feed waveguide. Subsequently, the array performance was analyzed by the full wave method of moments solution to the pertinent integral equations. Monte Carlo simulations were also carried out to account for amplitude and phase errors introduced for the aperture distribution due to modeling errors as well as manufacturing tolerances. If the design margins for the average sidelobe level and the average return loss were not adequate, array architecture, lattice spacing, aperture distribution, and waveguide dimensions were varied in subsequent iterations. Once the design margins were found to be adequate, the iteration was stopped and a good design was achieved. A symmetric array architecture was found to meet the design specification with adequate margin. The specifications were near 40 dB for angular regions beyond 30 degrees from broadside. Separable Taylor distribution with nbar=4 and 35 dB sidelobe specification was chosen for each principal plane. A non-separable distribution obtained by the genetic algorithm was found to have similar characteristics. The element spacing was obtained to provide the required beamwidth and close to a null in the E

  6. 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.)

  7. 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.

  8. 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.

  9. A Novel Dual-Band Circularly Polarized Rectangular Slot Antenna

    Directory of Open Access Journals (Sweden)

    Biao Li

    2016-01-01

    Full Text Available A coplanar waveguide fed dual-band circularly polarized rectangular slot antenna is presented. The proposed antenna consists of a rectangular metal frame acting as a ground and an S-shaped monopole as a radiator. The spatial distribution of the surface current density is employed to demonstrate that the circular polarization is generated by the S-shaped monopole which controls the path of the surface currents. An antenna prototype, having overall dimension 37 × 37 × 1 mm3, has been fabricated on FR4 substrate with dielectric constant 4.4. The proposed antenna achieves 10 dB return loss bandwidths and 3 dB axial ratio (AR in the frequency bands 2.39–2.81 GHz and 5.42–5.92 GHz, respectively. Both these characteristics are suitable for WLAN and WiMAX applications.

  10. A Novel Triangular Shaped UWB Fractal Antenna Using Circular Slot

    Science.gov (United States)

    Shahu, Babu Lal; Pal, Srikanta; Chattoraj, Neela

    2016-03-01

    The article presents the design of triangular shaped fractal based antenna with circular slot for ultra wideband (UWB) application. The antenna is fed using microstrip line and has overall dimension of 24×24×1.6 mm3. The proposed antenna is covering the wide frequency bandwidth of 2.99-11.16 GHz and is achieved using simple fractal based triangular-circular geometries and asymmetrical ground plane. The antenna is designed and parametrical studies are performed using method of moment (MOM) based Full Wave Electromagnetic (EM) software Simulator Zeland IE3D. The prototype of proposed antenna is fabricated and tested to compare the simulated and measured results of various antenna parameters. The antenna has good impedance bandwidth, nearly constant gain and stable radiation pattern. Measured return loss shows fair agreement with simulated one. Also measured group delay variation obtained is less than 1.0 ns, which proves good time domain behavior of the proposed antenna.

  11. Multiple steady fluid flows in a slot-ventilated enclosure

    International Nuclear Information System (INIS)

    Zhao Fuyun; Liu Di; Tang Guangfa

    2008-01-01

    Present work numerically investigates three-dimensional non-linear aerodynamic structures of airflow in a slot-ventilated compartment with three ports. A numerical code based on Reynolds average Navier-Stokes equations and Reynolds stress turbulence model was validated, and successfully conducted for simulating the airflow in the studied room. Numerical results are particularly presented to illustrate the effects of the inlet airflow velocity, enclosure width, supplying ports elevation and Reynolds number on the multiple flow patterns and the associated ventilation flow rate and blowing-axial momentum decay for equal-magnitude opposite jet flows. It is shown that the room airflow rate and the shift of jet flow interface can be promoted or inhibited, depending strongly on the jet velocity, enclosure width and elevation of supplying ports

  12. Silicone Rubber Superstrate Loaded Patch Antenna Design Using Slotting Technique

    Science.gov (United States)

    Kaur, Bhupinder; Saini, Garima; Saini, Ashish

    2016-09-01

    For the protection of antenna from external environmental conditions, there is a need that antenna should be covered with a stable, non-reactive, highly durable and weather resistive material which is insensitive to changing external environment. Hence, in this paper silicone rubber is proposed as a superstrate layer for patch antenna for its protection. The electrical properties of silicon rubber sealant are experimentally found out and its effect of using as superstrate on coaxial fed microstrip patch antenna using transmission line model is observed. The overall performance is degraded by slightly after the use of superstrate. Further to improve the performance of superstrate loaded antenna, patch slots and ground defects have been proposed. The proposed design achieves the wideband of 790 MHz (13.59 %), gain of 7.12 dB, VSWR of 1.12 and efficiency of 83.02 %.

  13. Quad-Band U-Slot Antenna for Mobile Applications

    Directory of Open Access Journals (Sweden)

    R. L. Ruiz

    2006-06-01

    Full Text Available In this paper, two different planar quad-band antennas are designed, modeled, fabricated and measured. Subsequently, the antennas are redesigned using an electromagnetic band gap substrate (EBG. Those new planar antennas operate in four frequency bands: 900 MHz, 1 800 MHz (both GSM, 1 900 MHz (USA and 2 400 to 2 500 MHz (Bluetooth The antenna has four narrow U-shaped slots etched to the patch. Using software, CST Microwave Studio [1], Zeland IE3D [2], and FEMLAB [3], simulations have been carried out to investigate the antenna's performance and characteristics. The antennas designed have been also built and measured to compare the real results with those obtained from the simulations.

  14. 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.

  15. 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.

  16. Integration of carbon nanotubes in slot waveguides (Conference Presentation)

    Science.gov (United States)

    Durán-Valdeiglesias, Elena; Zhang, Weiwei; Hoang, Thi Hong Cam; Alonso-Ramos, Carlos; Serna, Samuel; Le Roux, Xavier; Cassan, Eric; Balestrieri, Matteo; Keita, Al-Saleh; Sarti, Francesco; Biccari, Francesco; Torrini, Ughetta; Vinattieri, Anna; Yang, Hongliu; Bezugly, Viktor; Cuniberti, Gianaurelio; Filoramo, Arianna; Gurioli, Massimo; Vivien, Laurent

    2016-05-01

    Demanding applications such as video streaming, social networking, or web search relay on a large network of data centres, interconnected through optical links. The ever-growing data rates and power consumption inside these data centres are pushing copper links close to their fundamental limits. Optical interconnects are being extensively studied with the purpose of solving these limitations. Among the different possible technology platforms, silicon photonics, due to its compatibility with the CMOS platform, has become one of the preferred solutions for the development of the future generation photonic interconnects. However, the on-chip integration of all photonic and optoelectronic building blocks (sources, modulators and detectors…) is very complex and is not cost-effective due to the various materials involved (Ge for detection, doped Si for modulators and III-V for lasing). Carbon nanotubes (CNTs) are nanomaterials of great interest in photonics thanks to their fundamental optical properties, including near-IR room-temperature foto- and electro- luminescence, Stark effect, Kerr effect and absorption. In consequence, CNTs have the ability to emit, modulate and detect light in the telecommunications wavelength range. Furthermore, they are being extensively developed for new nano-electronics applications. In this work, we propose to use CNTs as active material integrated into silicon photonics for the development of all optoelectronic devices. Here, we report on the development of new integration schemes to couple the light emission from CNTs into optical resonators implemented on the silicon-on-insulator and silicon-nitride-on-insulator platforms. A theoretical and experimental analysis of the light interaction of CNTs with micro-ring resonators based on strip and slot waveguides and slot photonic crystal heterostructure cavities were carried out.

  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. Self-regulated model of galactic spiral structure formation.

    Science.gov (United States)

    Cartin, Daniel; Khanna, Gaurav

    2002-01-01

    The presence of spiral structure in isolated galaxies is a problem that has only been partially explained by theoretical models. Because the rate and pattern of star formation in the disk must depend only on mechanisms internal to the disk, we may think of the spiral galaxy as a self-regulated system far from equilibrium. This paper uses this idea to look at a reaction-diffusion model for the formation of spiral structures in certain types of galaxies. In numerical runs of the model, spiral structure forms and persists over several revolutions of the disk, but eventually dies out.

  20. Spread of the spiraling white fly Aleurodicus dispersus (Homoptera ...

    African Journals Online (AJOL)

    Spread of the spiraling white fly Aleurodicus dispersus (Homoptera: Aleyrodidae) and its parasitoids Encarcia species (Hymenoptera: Aphelinidae) on horticultural plants in Northwest and Central Nigeria.

  1. Topological Signatures in the Electronic Structure of Graphene Spirals

    DEFF Research Database (Denmark)

    Avdoshenko, Stas.M.; Koskinen, Pekka; Sevincli, Haldun

    2013-01-01

    and graphene systems. Here, we introduce topologically distinct graphene forms - graphene spirals - and employ density-functional theory to investigate their geometric and electronic properties. We found that the spiral topology gives rise to an intrinsic Rashba spin-orbit splitting. Through a Hamiltonian...... constrained by space curvature, graphene spirals have topologically protected states due to time-reversal symmetry. In addition, we argue that the synthesis of such graphene spirals is feasible and can be achieved through advanced bottom-up experimental routes that we indicate in this work....

  2. Virtual bronchoscopy based on spiral CT images

    Science.gov (United States)

    Englmeier, Karl-Hans; Haubner, Michael; Krapichler, Christian; Schuhmann, Dietrich; Seemann, Mark; Fuerst, H.; Reiser, Maximilian

    1998-06-01

    Purpose: To improve the diagnosis of pathologic modified airways, a visualization system has been developed and tested based on the techniques of digital image analysis, synthesis of spiral CT and the visualization by methods of virtual reality. Materials and Methods: 20 patients with pathologic modifications of the airways (tumors, obstructions) were examined with Spiral-CT. The three-dimensional shape of the airways and the lung tissue is defined by a semiautomatic volume growing method and a following geometric surface reconstruction. This is the basis of a multidimensional display system which visualizes volumes, surfaces and computation results simultaneously. To enable the intuitive and immersive inspection of the airways a virtual reality system, consisting of two graphic engines, a head mounted display system, data gloves and specialized software was integrated. Results: In 20 cases the extension of the pathologic modification of the airways could be visualized with the virtual bronchoscopy. The user interacts with and manipulates the 3D model of the airways in an intuitive and immersive way. In contrast to previously proposed virtual bronchoscopy systems the described method permits truly interactive navigation and detailed exploration of anatomic structures. The system enables a user oriented and fast inspection of the volumetric image data. Conclusion: To support radiological diagnosis with additional information in an easy to use and fast way a virtual bronchoscopy system was developed. It enables the immersive and intuitive interaction with 3D Spiral CTs by truly 3D navigation within the airway system. The complex anatomy of the central tracheobronchial system could be clearly visualized. Peripheral bronchi are displayed up to 5th degree.

  3. Influence of slot width on the performance of multi-stage overtopping wave energy converters

    Directory of Open Access Journals (Sweden)

    Sirirat Jungrungruengtaworn

    2017-11-01

    Full Text Available A two-dimensional numerical investigation is performed to study the influence of slot width of multi-stage stationary floating overtopping wave energy devices on overtopping flow rate and performance. The hydraulic efficiency based on captured crest energy of different device layouts is compared with that of single-stage device to determine the effect of the geometrical design. The results show optimal trends giving a huge increase in overtopping energy. Plots of efficiency versus the relative slot width show that, for multi-stage devices, the greatest hydraulic efficiency is achieved at an intermediate value of the variable within the parametric range considered, relative slot width of 0.15 and 0.2 depending on design layouts. Moreover, an application of adaptive slot width of multi-stage device is investigated. The numerical results show that the overall hydraulic efficiency of non-adaptive and adaptive slot devices are approximately on par. The effect of adaptive slot width on performance can be negligible. Keywords: Wave energy converter, Overtopping, Multi-stage, Slot width

  4. 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)

  5. 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

  6. 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...

  7. [The characteristics of and social support for pathological gamblers among "pachinko" or "slot" users in Japan].

    Science.gov (United States)

    Kumagami, Takashi

    2014-01-01

    In Japan, there are one to two million people suspected of being pathological gamblers according to the definition in DSM-IV-TR. Almost all of them use "pachinko" or "slot," which are gambling stores, throughout Japan, that number 12,000 in total. However, the characteristics and ratio of pathological "pachinko" and "slot" gamblers have not been investigated. The author aimed to determine the characteristics, ratio, and social support available for these users. The author administered an internet survey for users of "pachinko" or "slot." Two hundred and fifty users visited "pachinko" or "slot" stores more than twice a week, and 250 users visited once a week or once a month. The Japanese version of the South Oaks Gambling Screen was administered, and gamblers were asked about their awareness of pathological gambling and the condition of their social support. The author observed that 70.2% of "pachinko" or "slot" users were suspected pathological gamblers and 28.6% of "pachinko" or "slot" users were severe gamblers. A total of 39.3% of them were aware of their pathological gambling, and 6.5% of users who had awareness of pathological gambling had social support. However, most of their social support consisted of family and friends, and almost none of them attended psychiatric clinics, community health centers, or self-help groups like gamblers anonymous. Almost all "pachinko" or "slot" users were suspected of being pathological or severe gamblers. However, they did not approach psychiatric facilities or self-help groups. The author strongly recommends the need for educational programs in junior or high school to prevent future pathological gambling, and create awareness of the dangers of pathological gambling through TV commercials and "pachinko" or "slot" stores. Pathological gambling is a disease that afflicts many people; hence, psychiatric and social welfare professionals should continue to stress the dangers of and offer prevention programs for "pachinko" or

  8. FEM-based Analysis of a Hybrid Synchronous Generator with Skewed Stator Slots

    Directory of Open Access Journals (Sweden)

    MUNTEANU, A.

    2011-11-01

    Full Text Available The paper presents a simulation study of a hybrid synchronous generator (dual excitation system - permanent magnets and electromagnets with skewed stator slots. The main goal is to establish if the skewing of the slots brings a significant improvement of the air-gap flux density and of the induced stator voltage. The skewness angle is the parameter in discussion. The study is based on finite element method analysis. Due to the particular geometry of the stator slots, a multilayer approach is employed.

  9. Coupling element antenna with slot tuning for handheld devices at LTE frequencies

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Pelosi, Mauro; Franek, Ondrej

    2012-01-01

    . A reconfigurable slot is inserted in the ground plane in order to lower its resonance frequency. The tuning is done by a capacitor across the slot. It is shown that covering all frequencies between the 900-GSM band and the 700-LTE band can be achieved. The radiating structure also presents a resonance in the high...... LTE band which is unaffected by the tuning mechanism of the lower band. Moreover, the efficiency can be optimized by an analysis of the currents across the slot. The study also shows that holding the device does not lead to additional mismatch losses which will further improve the overall efficiency....

  10. Effect of Cutting Parameters on Microhardness in 2 mm Slot Milling Hardened Tool Steel

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2004-01-01

    This paper presents an experimental study on the dependency of surface integrity on cutting parameters in slot milling of hardened tool steel. A series of 2 mm slot milling tests have been performed with different cutting parameters. Microhardness was chosen for evaluation of subsurface integrity....... The process was found to be sensitive to cutting parameters. An increase of feed per tooth or depth of cut produced a reduction of the microhardness of the slot surface. An optimal combination of machining parameters was found to be 80-110 m/min in cutting speed, 0.005 mm in feed per tooth and 0.1 mm in axial...

  11. 2D array based on fermat spiral

    Science.gov (United States)

    Martínez, O.; Martín, C. J.; Godoy, G.; Ullate, L. G.

    2010-01-01

    The main challenge faced by 3D ultrasonic imaging with 2D array transducer is the large number of elements required to achieve an acceptable level of quality in the images. Therefore, the optimization of the array layout to reduce the number of active elements in the aperture has been a research topic in the last years. Nowadays, CMUT array technology has made viable the production of 2D arrays with larger flexibility on elements size, shape and position. This is opening new options in 2D array design, allowing to revise as viable alternatives others layouts that had been studied in the past, like circular and Archimedes spiral layout. In this work the problem of designing an imaging system array with a diameter of 60 λ and a limited number of elements using the Fermat spiral layout has been studied. This study has been done for two different numbers of electronic channels (N = 128 and N = 256). As summary, a general discussion of the results and the most interesting cases are presented.

  12. 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.

  13. A phenomenological theory for polarization flop in spiral multiferroic ...

    Indian Academy of Sciences (India)

    driven polarization flop in TbMnO3. The Néel wall-like magnetic structure in spiral multiferroics induces a space-dependent internal magnetic field which exerts a torque on spins to rotate bc-spiral to abspiral. The external magnetic field is argued ...

  14. A phenomenological theory for polarization flop in spiral multiferroic ...

    Indian Academy of Sciences (India)

    a space-dependent internal magnetic field which exerts a torque on spins to rotate bc-spiral to ab- spiral. The external ... Fv; 75.85.+t. Electric control of magnetization and magnetic control of polarization have been long ... divergence of magnetization, an internal field is induced which has important physical. Figure 1. ab ...

  15. On galaxy spiral arms' nature as revealed by rotation frequencies

    NARCIS (Netherlands)

    Roca-Fabrega, Santi; Valenzuela, Octavio; Figueras, Francesca; Romero-Gomez, Merce; Velazquez, Hector; Antoja Castelltort, Teresa; Pichardo, Barbara

    2013-01-01

    High-resolution N-body simulations using different codes and initial condition techniques reveal two different behaviours for the rotation frequency of transient spiral arms like structures. Whereas unbarred discs present spiral arms nearly corotating with disc particles, strong barred models

  16. 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)

  17. 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…

  18. 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

  19. Standing surface waves in dusty microwave slot-excited plasma

    International Nuclear Information System (INIS)

    Ostrikov, K.N.; Yu, M.Y.; Sugai, H.

    2000-01-01

    Full text: The effect of charged dust particles on microwave slot-excited plasma has been studied. The dusts absorb significant proportion of the plasma electrons, which leads to a substantial modification of the electromagnetic field structure. The overall charge balance and the eigenfrequencies of the standing TM electromagnetic surface modes are modified by the presence of dust. It has been found that the originally excited surface waves can be shifted out of resonance. For certain proportions of dusts, mode conversion appears to be possible. Microwave gas discharges sustained by surface waves (SW) are promising for many industrial applications as sources of large-volume and large-area low-temperature plasmas. Here, we study the surface-wave sustained microwave plasma reactor contaminated by fine dust particles that usually appear as a substrate-etching product or as a result of polymerization in the gaseous phase. The structure that models the slot-excited planar plasma source is considered. A vertical circular cylinder is short-circuited at its top by a metal plate. A dielectric layer isolates the cylinder top from the plasma, and the chamber bottom is open. We have shown that uncontrolled release of the dusts in the discharge chamber can adversely affect the discharge performance and under certain conditions cause a discharge disruption. This can best be understood by noting that macroparticles absorb a significant proportion of plasma electrons and hence modify the ionization-recombination balance. Moreover, stable operation of the microwave surface-wave sustained discharge depends on the resonant conditions for the operating mode, and it is thus crucial to understand how dusts affect the eigenfrequencies of the SWs. We have demonstrated that introduction of additional amounts of contaminant results in a significant shift of the electron plasma density from its resonant value for the initially excited resonant mode. The system can thus be moved out of

  20. 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.

  1. 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

  2. Some statistical properties of spiral galaxies along the Hubble sequence

    Science.gov (United States)

    Ma, Jun; Zhao, Jun-liang; Zhang, Fei-peng; Peng, Qiu-he

    A statistical study has been made for the variations along the Hubble sequence, os such parameters as the degree of tightness of winding of spiral arm λ, the pitch angle μ, the flatness of the disk H/ D25 and the thickness H along the Hubble sequence for 365 spiral galaxies published in A&Ap Supplement Series. The mean values of these quantities for the various Hubble types have been obtained for the first time. The results of the statistics show clearly 1) that the Hubble classification of spiral galaxies is one which has only a qualitative and statistical significance, and 2) that the dispersion relation in the density wave theory is valid for most spiral galaxies, i.e., the arms of most spiral galaxies satisfy the requirements of being tightly wound.

  3. The Effects of Spiral Taping Treatment on Low Back Pain

    Directory of Open Access Journals (Sweden)

    Hwang Jae-Ok

    2006-02-01

    Full Text Available Objective : The purpose of this study is to estimate the effects of spiral taping treatment on low back pain. Methods : 420 low back pain patients were treated with spiral taping or spiral taping plus herbal medicine, and no other treatments such as acupuncture, herbal acupuncture, and chiropractic therapy were added. We evaluated the improvement by physical examination and pain. Results : 364 patients felt no pain or inconvenience of daily life and 43 patients showed improvement of pain or symptom after 1 month of treatment. 13 patients showed same pain with before treatment. Conclusions : These results suggest spiral taping treatments contribute to the improvement of low back pain. Further study is needed for the confirmation of this effect of spiral taping treatments on low back pain.

  4. A hybrid electro-optic polymer and TiO2 double-slot waveguide modulator.

    Science.gov (United States)

    Qiu, Feng; Spring, Andrew M; Maeda, Daisuke; Ozawa, Masa-aki; Odoi, Keisuke; Otomo, Akira; Aoki, Isao; Yokoyama, Shiyoshi

    2015-02-24

    An electro-optic (EO) modulator using a TiO2 slot hybrid waveguide has been designed and fabricated. Optical mode calculations revealed that the mode was primarily confined within the slots when using a double-slot configuration, thus achieving a high EO activity experimentally. The TiO2 slots also acted as an important barrier to induce an enhanced DC field during the poling of the EO polymer and the driving of the EO modulator. The hybrid phase modulator exhibited a driving voltage (Vπ) of 1.6 V at 1550 nm, which can be further reduced to 0.8 V in a 1 cm-long push-pull Mach-Zehnder interferometer (MZI) structure. The modulator demonstrated a low propagation loss of 5 dB/cm and a relatively high end-fire coupling efficiency.

  5. Low-speed aerodynamic test of an axisymmetric supersonic inlet with variable cowl slot

    Science.gov (United States)

    Powell, A. G.; Welge, H. R.; Trefny, C. J.

    1985-01-01

    The experimental low-speed aerodynamic characteristics of an axisymmetric mixed-compression supersonic inlet with variable cowl slot are described. The model consisted of the NASA P-inlet centerbody and redesigned cowl with variable cowl slot powered by the JT8D single-stage fan simulator and driven by an air turbine. The model was tested in the NASA Lewis Research Center 9- by 15-foot low-speed tunnel at Mach numbers of 0, 0.1, and 0.2 over a range of flows, cowl slot openings, centerbody positions, and angles of attack. The variable cowl slot was effective in minimizing lip separation at high velocity ratios, showed good steady-state and dynamic distortion characteristics, and had good angle-of-attack tolerance.

  6. Pathological gambling: A comparison of gambling at German-style slot machines and "Classical" gambling.

    Science.gov (United States)

    Fabian, T

    1995-09-01

    German-style slot machines and related legal issues are described. On the basis of a survey on 437 members of self-help groups (Gamblers Anonymous) in Germany, slot machine gamblers were compared with casino gamblers on such variables as sociodemographic data, gambling behaviour, financial expenditure, emotional experience while gambling, symptoms of pathological gambling, psychosocial consequences and gambling related delinquency. The casino gamblers' gambling behaviour is financially more extensive. There were similarities regarding the emotional intensity of the gambling experience. However the casino gamblers show more pronounced symptoms of pathological gambling and the psychosocial consequences of their gambling behaviour are more severe. In spite of these differences, the data show that for young people slot machines can be as stimulating and therefore as dangerous as casino gambling. The young slot machine gambler runs a similar risk of acquiring a pathological gambling habit as the casino gambler.

  7. Design of slotted high quality factor photonic-crystal nanocavities embedded in electro-optic polymers

    Science.gov (United States)

    Nakadai, Masahiro; Konoike, Ryotaro; Tanaka, Yoshinori; Asano, Takashi; Noda, Susumu

    2017-09-01

    We improve design quality factors of slotted photonic crystal nanocavities embedded in electro-optic polymers (EOPs), which enables control of resonant wavelengths without the use of light-absorbing free carriers. We form nanocavities by modifying single- and double-slotted line-defect waveguides with lattice-constant modulations analytically determined based on dispersions of the waveguides. A double-slotted nanocavity achieves a fourfold increase in Q factor (36 million) compared to a single-slotted nanocavity with similar modulation of lattice constants. Both structures can realize large concentration of light in the EOP region (50%), and resonant wavelength modulations of ∼0.01% are expected with applied voltage of 2 V.

  8. Capture efficiency measurement of pollutants over a workbench with the reinforced slot exhaust system

    Directory of Open Access Journals (Sweden)

    Pavelek M.

    2013-04-01

    Full Text Available The paper deals with the measurement of the capture efficiency of pollutants by the slot reinforced exhaust system situated in two positions over the workbench. The slot reinforced exhaust system, which is known as REEXS, is the traditional slot exhaust hood equipped with an air supply inlet that intensifies exhausting along the axis of the exhaust hood. It can operate in traditional or reinforced exhaust modes. Measurements were made for the same air velocity in the suction slot and with the different momentum flux ratio of supplied and exhausted air flow. The tracer gas method was used for the capture efficiency measurement of the system. As the tracer gas the carbon dioxide was chosen. The knowledge of the shape and range of the effective exhaust area for various configurations in front of the exhaust hood is important for the exhaust hood setting according to a source of pollutants.

  9. Implementation of rectangular slit-inserted ultra-wideband tapered slot antenna.

    Science.gov (United States)

    Kim, Sun-Woong; Choi, Dong-You

    2016-01-01

    In this paper, a tapered slot antenna capable of ultra-wideband communication was designed. In the proposed antenna, rectangular slits were inserted to enhance the bandwidth and reduce the area of the antenna. The rectangular slit-inserted tapered slot antenna operated at a bandwidth of 8.45 GHz, and the bandwidth improved upon the basic tapered slot antenna by 4.72 GHz. The radiation pattern of the antenna was suitable for location recognition in a certain direction owing to an appropriate 3 dB beam width. The antenna gain was analyzed within the proposed bandwidth, and the highest gain characteristic at 7.55 dBi was exhibited at a 5-GHz band. The simulation and measurement results of the proposed tapered slot antenna were similar.

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

    Energy Technology Data Exchange (ETDEWEB)

    Baum, Ulrich E-mail: baum@idr.med.uni-erlangen.de; Greess, Holger; Lell, Michael; Noemayr, Anton; Lenz, Martin

    2000-03-01

    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. 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

  12. A Method to Automate Identification of Spiral Arms in Galaxies

    Science.gov (United States)

    Lacey, Christina K.; Mercer, K.

    2014-01-01

    We present our preliminary results in identifying the spiral arms of NGC 6946 using a nearest-neighbors analysis. NGC 6946 is grand design spiral galaxy with well-defined arms. The spiral arms were previously identified in an Hα image and traced out by Matonick, D. et al., ApJS, 113, 333, (1997) by visual inspection. We want to develop a computer algorithm that will identify the spiral arms automatically. Once the spiral arms have been found digitally, we can use this information to compare the spiral arms with the locations of compact objects such as supernova remnants and perform statistical tests, for example, to determine if the supernova remnants are associated with the spiral arms. We are using the publicly available program PyFITS, a development project of the Science Software Branch at the Space Telescope Science Institute (STScI) that is available for software download from STScI, to perform a computer-based image analysis. We have written python macros that interact with the already written image manipulation and display features of PyFITS to perform the image analysis and implement a nearest-neighbors algorithm to identify and link the centers of the high emission regions from the spiral arm regions. Our code currently identifies the centers of the high emission regions, but more work is needed to link up these sites and draw out the spiral arms. Future work includes improving the code to better identify spiral arms and converting the code to work on the Astropy, a community-developed core Python package for Astronomy (Robitaille, T. P., et al. A&A 558, A33, 2013).

  13. Upright Biplanar Slot Scanning in Pediatric Orthopedics: Applications, Advantages, and Artifacts.

    Science.gov (United States)

    Hull, Nathan C; Binkovitz, Larry A; Schueler, Beth A; Kolbe, Amy B; Larson, A Noelle

    2015-07-01

    Digital slot scanning is a relatively new technology that has been used for imaging of pediatric orthopedic conditions such as scoliosis and leg-length discrepancies. This article will review the clinical applications, advantages, and unique artifacts of this new technology. Upright biplanar slot scanners acquire high-resolution radiographs simultaneously in two orthogonal planes with reduced radiation dose. Other advantages include a more physiologic weightbearing imaging position, improved Cobb angle measurements, and 3D modeling.

  14. Pulsed electromagnetic field radiation from a narrow slot antenna with a dielectric layer

    OpenAIRE

    Stumpf, M.; de Hoop, A. T.; Lager, I. E.

    2010-01-01

    Analytic time domain expressions are derived for the pulsed electromagnetic field radiated by a narrow slot antenna with a dielectric layer in a two?dimensional model configuration. In any finite time window of observation, exact pulse shapes for the propagated, reflected, and refracted wave constituents are constructed with the aid of the modified Cagniard method (Cagniard?DeHoop method). Numerical results are presented for vanishing slot width and field pulse shapes at the dielectric/free s...

  15. Experimental investigation of frequency characteristics of the multistage slot membranes waveguide filters

    Directory of Open Access Journals (Sweden)

    Kopylova Natalia

    2017-01-01

    Full Text Available In this article, we present results of experimental investigation of amplitude-frequency characteristics (AFC of the five-stage “filters with the waveguide-slot membranes” (FWSM in the range of frequencies 5.4…8.5 GHz for six filters. Article shows the following trend change filter frequency response by increasing the width of the slots of the second and fourth membranes: decrease the quality factor, resonant frequency increase, reducing losses in the passband.

  16. An integrated container management model for optimizing slot allocation plan and empty container repositioning

    OpenAIRE

    Chia-hui Chang; Lawrence W Lan; Mee Lee

    2015-01-01

    This article proposes an integrated container management model to jointly optimize slot allocation plan for loaded containers and reposition for empty containers in a shipping network. The proposed model employs linear programming to formulate loaded and empty container shipping problems in a bi-level structure. In upper level the loaded container slot allocation plan aims to maximize operational profits for each service route; whereas in lower level the reposition of empty containers aims to...

  17. Modeling fiber motion in a pulp pressure screen: the effect of slot shape

    International Nuclear Information System (INIS)

    Dong, S.; Salcudean, M.; Gartshore, I.

    2003-01-01

    A pressure screen is a piece of equipment in the pulp and paper industry used either to remove contaminants from the pulp suspension or to separate fibers having different properties. Contaminants such as fiber bundles, bark and plastic specks are introduced when fibers are separated from the wood by mechanical or chemical pulping processes. Contaminants significantly affect the strength and smoothness of the paper and must be removed before the final paper is produced. The screen plate is a critical part of the pressure screen and its design is the key to screen performance. This paper uses a new and comprehensive CFD simulation tool to examine the flow and fiber behavior in a single slot screen having any reasonable slot shape. -This simulation tool includes three coupled models: first, the flow model solves the Reynolds Averaged Navier-Stokes (RANS) equation using the standard k - ε turbulence model to predict the flow field in the equipment. Second, a three-dimensional flexible fiber model is used to track the fiber trajectory in the screen. Third, a very general wall model is used to deal with the case when a fiber touches the equipment wall. The simulated results show that the slot shape has a critical influence on fiber behavior and screen performance. Three general slot shapes were investigated: the smooth slot, the step-step contour slot and slope-slope contour slot. Of these the slope-slope contour slot provides the best passage for the fibers with a length of 1mm and 3mm. (author)

  18. Slot-dimer babinet metamaterials as polarization shapers for terahertz waves

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei; Chigrin, D. N.; Lavrinenko, Andrei

    2013-01-01

    We theoretically study optical properties of free-standing metallic membranes patterned with an array of two-slot elements (dimers) comprising two rectangular slots of different dimensions and orientation. It is shown that these structures feature extraordinary optical transmission with strong...... and spectrally selective polarization conversion capabilities. The output polarization is highly dependent on the dimer geometry, which can be used in the design of compact polarization shapers for terahertz waves....

  19. Queueing models for token and slotted ring networks. Thesis

    Science.gov (United States)

    Peden, Jeffery H.

    1990-01-01

    Currently the end-to-end delay characteristics of very high speed local area networks are not well understood. The transmission speed of computer networks is increasing, and local area networks especially are finding increasing use in real time systems. Ring networks operation is generally well understood for both token rings and slotted rings. There is, however, a severe lack of queueing models for high layer operation. There are several factors which contribute to the processing delay of a packet, as opposed to the transmission delay, e.g., packet priority, its length, the user load, the processor load, the use of priority preemption, the use of preemption at packet reception, the number of processors, the number of protocol processing layers, the speed of each processor, and queue length limitations. Currently existing medium access queueing models are extended by adding modeling techniques which will handle exhaustive limited service both with and without priority traffic, and modeling capabilities are extended into the upper layers of the OSI model. Some of the model are parameterized solution methods, since it is shown that certain models do not exist as parameterized solutions, but rather as solution methods.

  20. Moment method analysis of linearly tapered slot antennas

    Science.gov (United States)

    Koeksal, Adnan

    1993-01-01

    A method of moments (MOM) model for the analysis of the Linearly Tapered Slot Antenna (LTSA) is developed and implemented. The model employs an unequal size rectangular sectioning for conducting parts of the antenna. Piecewise sinusoidal basis functions are used for the expansion of conductor current. The effect of the dielectric is incorporated in the model by using equivalent volume polarization current density and solving the equivalent problem in free-space. The feed section of the antenna including the microstripline is handled rigorously in the MOM model by including slotline short circuit and microstripline currents among the unknowns. Comparison with measurements is made to demonstrate the validity of the model for both the air case and the dielectric case. Validity of the model is also verified by extending the model to handle the analysis of the skew-plate antenna and comparing the results to those of a skew-segmentation modeling results of the same structure and to available data in the literature. Variation of the radiation pattern for the air LTSA with length, height, and taper angle is investigated, and the results are tabulated. Numerical results for the effect of the dielectric thickness and permittivity are presented.

  1. Thinning and rupture of liquid films by moving slot jets.

    Science.gov (United States)

    Berendsen, Christian W J; Zeegers, Jos C H; Darhuber, Anton A

    2013-12-23

    We present systematic experiments of the rupture and dewetting of thin films of a nonvolatile polar liquid on partially wetting substrates due to a moving slot jet, which impinges at normal incidence. The relative motion was provided by a custom-built spin coater with a bidirectionally accessible axis of rotation that enabled us to measure film thickness profiles in situ as a function of substrate velocity using dual-wavelength interference microscopy. On partially wetting polymeric substrates, dry spots form in liquid films with a residual thickness well below 1 μm. We measured the density of dry spots as well as the density and size distribution of the residual droplets as a function of film thickness. In a certain parameter range, the droplet distributions exhibit pronounced anisotropy due to the effect of long-range shear stresses on the dewetting rim instability. We find robust power-law scaling relations over a large range of film thicknesses and a striking similarity to literature data obtained with ultrathin polymer melt layers on silicon substrates.

  2. Collaborative en-route and slot allocation algorithm based on fuzzy comprehensive evaluation

    Science.gov (United States)

    Yang, Shangwen; Guo, Baohua; Xiao, Xuefei; Gao, Haichao

    2018-01-01

    To allocate the en-routes and slots to the flights with collaborative decision making, a collaborative en-route and slot allocation algorithm based on fuzzy comprehensive evaluation was proposed. Evaluation indexes include flight delay costs, delay time and the number of turning points. Analytic hierarchy process is applied to determining index weights. Remark set for current two flights not yet obtained the en-route and slot in flight schedule is established. Then, fuzzy comprehensive evaluation is performed, and the en-route and slot for the current two flights are determined. Continue selecting the flight not yet obtained an en-route and a slot in flight schedule. Perform fuzzy comprehensive evaluation until all flights have obtained the en-routes and slots. MatlabR2007b was applied to numerical test based on the simulated data of a civil en-route. Test results show that, compared with the traditional strategy of first come first service, the algorithm gains better effect. The effectiveness of the algorithm was verified.

  3. EFFECTS OF SLOTTED BLADING ON SECONDARY FLOW IN HIGHLY LOADED COMPRESSOR CASCADE

    Directory of Open Access Journals (Sweden)

    RAMZI MDOUKI

    2013-10-01

    Full Text Available With the aim to increase allowable blade loadings and enlarge stable operating range in highly loaded compressor, this work is carried out in order to explore the potential of passive control via slotted bladings in linear cascade configurations under both design and stall conditions. Through an extensive 2D-numerical study, the effects of location, width and slope of slots were analysed and the best configuration was identified. Based on the optimal slot, the 3D aerodynamic performances of cascade were studied and the influence of slotted blading to control endwall flow was investigated. Both 2D and 3D calculations are performed on steady RANS solver with standard k-epsilon turbulence model and low Mach number regime. The total loss coefficient, turning angle and flow visualizations on the blade and end-wall surfaces are adopted to describe the different configurations. The obtained results show, for 2D situation, that a maximum of 28.3% reduction in loss coefficient had been reached and the flow turning was increased with approximately 5°. Concerning 3D flow fields the slots marked their benefit at large incoming flow angles which delays the separation on both end wall and blade suction surface at mid span. However, at design conditions, the slotted blades are not able to control secondary flows near the wall and so, lose their potential.

  4. Analysis of voltage unbalance effects on induction motors with open and closed slots

    International Nuclear Information System (INIS)

    Donolo, Pablo; Bossio, Guillermo; De Angelo, Cristian

    2011-01-01

    Research highlights: → We study the increase of losses in the induction motor (IM) with voltage unbalance. → We take into account the variations in the negative-sequence impedance of the rotor. → We analyze the performance in IM with open and closed rotor slots. → For both type of rotors, we get the derating factor for different levels of unbalance. → IM with closed-slot are less affected by voltage unbalance than open-slot ones. -- Abstract: This paper aims to complement studies concerning the influence of voltage unbalance on the performance of induction motors. We use sequence equivalent circuits to determine the increase of losses in the induction motor. We take into account the dependence of the rotor negative-sequence reactance with the load state and the increase in rotor resistance with the negative-sequence currents. Variations in the negative-sequence impedance are related with the structural characteristics of the rotor. We analyze motors with open and closed rotor slots, because the impedance of rotors with closed slots grows considerably when the load is less than rated, producing lower negative-sequence currents and lower losses. Increased rotor impedance in closed slot motors protects these motors against problems due to unbalanced supply voltage. For both type of rotors, we analyze motor derating factor based on voltage unbalance and increases in total losses and rotor losses.

  5. Three-dimensional imaging of intracochlear tissue by scanning laser optical tomography (SLOT)

    Science.gov (United States)

    Tinne, N.; Nolte, L.; Antonopoulos, G. C.; Schulze, J.; Andrade, J.; Heisterkamp, A.; Meyer, H.; Warnecke, A.; Majdani, O.; Ripken, T.

    2016-02-01

    The presented study focuses on the application of scanning laser optical tomography (SLOT) for non-destructive visualization of anatomical structures inside the human cochlea ex vivo. SLOT is a laser-based highly efficient microscopy technique, which allows for tomographic imaging of the internal structure of transparent large-scale specimens (up to 1 cm3). Thus, in the field of otology this technique is best convenient for an ex vivo study of the inner ear anatomy. For this purpose, the preparation before imaging comprises mechanically assisted decalcification, dehydration as well as optical clearing of the cochlea samples. Here, we demonstrate results of SLOT visualizing hard and soft tissue structures of the human cochlea with an optical resolution in the micrometer range using absorption and autofluorescence as contrast mechanisms. Furthermore, we compare our results with the method of X-ray micro tomography (micro-CT, μCT) as clinical gold standard which is based only on absorption. In general, SLOT can provide the advantage of covering all contrast mechanisms known from other light microscopy techniques, such as fluorescence or scattering. For this reason, a protocol for antibody staining has been developed, which additionally enables selective mapping of cellular structures within the cochlea. Thus, we present results of SLOT imaging rodent cochleae showing specific anatomical structures such as hair cells and neurofilament via fluorescence. In conclusion, the presented study has shown that SLOT is an ideally suited tool in the field of otology for in toto visualization of the inner ear microstructure.

  6. Frequency Reconfigurable Circular Patch Antenna with an Arc-Shaped Slot Ground Controlled by PIN Diodes

    Directory of Open Access Journals (Sweden)

    Yao Chen

    2017-01-01

    Full Text Available In this paper, a compact frequency reconfigurable circular patch antenna with an arc-shaped slot loaded in the ground layer is proposed for multiband wireless communication applications. By controlling the ON/OFF states of the five PIN diodes mounted on the arc-shaped slot, the effective length of the arc-shaped slot and the effective length of antennas current are changed, and accordingly six-frequency band reconfiguration can be achieved. The simulated and measured results show that the antenna can operate from 1.82 GHz to 2.46 GHz, which is located in DCS1800 (1.71–1.88 GHz, UMTS (2.11–2.20 GHz, WiBro (2.3–2.4 GHz, and Bluetooth (2.4–2.48 GHz frequency bands and so forth. Compared to the common rectangular slot circular patch antenna, the proposed arc-shaped slot circular patch antenna not only has a better rotational symmetry with the circular patch and substrate but also has more compact size. For the given operating frequency at 1.82 GHz, over 55% area reduction is achieved in this design with respect to the common design with rectangular slot. Since the promising frequency reconfiguration, this antenna may have potential applications in modern multiband and multifunctional mobile communication systems.

  7. Wind-tunnel investigation of an NACA 23012 airfoil with several arrangements of slotted flaps with extended lips

    Science.gov (United States)

    Lowry, John G

    1941-01-01

    An investigation was made in the NACA 7- by 10-foot wind tunnel to determine the effect of slot-lip location on the aerodynamic section characteristics of an NACA 23012 airfoil with a 30-percent-chord slotted flap. Tests were made with slot lips located at 90 and 100 percent of the airfoil chord and with two different flap shapes. The results are compared with a slotted flap previously developed by the National advisory Committee for Aeronautics with a slot lip located at 83 percent of the airfoil chord. The extension of the slot lip to the rear increased the section lift and pitching-moment coefficients. Comparisons made on a basis of pitching moment for a given tail length show that the Fowler type flap, lip extended to trailing edge of the airfoil, has the greatest section lift coefficient. For moderate tail lengths, 2 to 3 chord lengths, there was only a slight difference between the previously developed slotted flap and the slotted flap with slot lip extended to 90 percent of the airfoil chord. Of the three flaps tested, the Fowler flap had the lowest drag coefficient at high lift coefficients. The extension of the lower surface at the leading edge of the slot had a negligible effect on the profile drag of the airfoil-flap arrangement with the flap deflected when the lip terminated at 90 percent of the airfoil chord.

  8. Electromagnetic, flow and thermal study of a miniature planar spiral transformer with planar, spiral windings

    Directory of Open Access Journals (Sweden)

    J. B. DUMITRU

    2014-04-01

    Full Text Available This paper presents mathematical modeling and numerical simulation results for a miniature, planar, spiral transformer (MPST fabricated in micro-electromechanical MEMS technology. When the MPST is magnetic nanofluid cored, magnetization body forces occur, entraining it into a complex flow. This particular MPST design is then compared with other competing solutions concerning the lumped (circuit parameters. Finally, the heat transfer problem is solved for different electromagnetic working conditions to assess the thermal loads inside the MPST.

  9. 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.

  10. Processing fine stainless-steel slag using spiral concentration.

    Science.gov (United States)

    Wolfe, Eric R; Klima, Mark S

    2008-04-01

    In this study, the effectiveness of spiral concentration to process a fine (-1 mm) stainless-steel slag was evaluated. Specifically, testing was conducted to determine the feasibility of producing a high metal content stainless steel product and a low metal content aggregate product. This involved investigating a key operating variable for both five-and seven-turn spiral concentrators. The raw slag and spiral products were characterized to determine their respective size and metal distributions. Separation testing was carried out using the two full-scale spiral concentrators to evaluate the effects of feed solids concentration on spiral performance at solids feed rates ranging from 15 to 30 kg/min. The results indicated that under certain conditions, a high-quality metal fraction could be produced. For example, using the five-turn spiral, a product containing 95% metal was obtained at a low metal recovery. Both spirals were ineffective at concentrating the aggregate fraction. Overall, the feed solids concentration did not significantly affect the quality or recoveries of the products, particularly for feed solids concentrations less than 35% by weight. In order to improve the metal recoveries and to produce a low-metal aggregate material, reprocessing of the product streams and/or additional liberation of the raw slag would be required.

  11. Pancreatic adenocarcinoma : usefulness of two and three phase spiral CT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyeong Ah; Kim, Hyung Soo; Park, Cheol Min; Cha, In Ho [Korea Univ. College of Medicine, Seoul (Korea, Republic of)

    1996-10-01

    To evaluate the efficacy of each phases in two and three phase spiral CT in the detection of pancreatic adenocarcinoma. Two phase spiral CT images of 18 patients and three phase spiral CT images of 12 patients with pathologically-proven pancreatic ductal adenocarcinoma were retrospectively compared. Using a single spiral scan, images of early and delayed phases were obtained at 43 seconds and 2{approx}3minutes respectively initiating the after administration of 100-120cc of contrast material (2{approx}3cc/sec), Images of arterial, portal and delayed phases were also obtained at 25 and 60 seconds, and 3{approx}4minutes, respectively, by the use of a double spiral scan. CT scans were performed with 10mm collimation at 1:1 pitch table speed. Contrast between the tumor and adjacent pancreatic parenchyma were compared and graded and enhancement pattern of the tumor were analysed together. In 12 patients (66.7%), images of the early phase were superior to those of the delayed phase. images of the portal phase were superior to those of the arterial phase. Enhancement of tumor was seen in four patients;all tumors were less than 3cm in size. The early phase of two phase spiral CT is superior to the delayed phase and the portal phase of three phase spiral CT is superior to the arterial phase. Both arterial and portal phases are superior to the delayed phase.

  12. Spiral Antenna-Coupled Microbridge Structures for THz Application.

    Science.gov (United States)

    Gou, Jun; Zhang, Tian; Wang, Jun; Jiang, Yadong

    2017-12-01

    Bolometer sensor is a good candidate for THz imaging due to its compact system, low cost, and wideband operation. Based on infrared microbolometer structures, two kinds of antenna-coupled microbridge structures are proposed with different spiral antennas: spiral antenna on support layer and spiral antenna with extended legs. Aiming at applications in detection and imaging, simulations are carried out mainly for optimized absorption at 2.52 THz, which is the radiation frequency of far-infrared CO 2 lasers. The effects of rotation angle, line width, and spacing of the spiral antenna on THz wave absorption of microbridge structures are discussed. Spiral antenna, with extended legs, is a good solution for high absorption rate at low absorption frequency and can be used as electrode lead simultaneously for simplified manufacturing process. A spiral antenna-coupled microbridge structure with an absorption rate of more than 75% at 2.52 THz is achieved by optimizing the structure parameters. This research demonstrates the use of different spiral antennas for enhanced and tunable THz absorption of microbridge structures and provides an effective way to fabricate THz microbolometer detectors with great potential in the application of real-time THz imaging.

  13. Airport slots and slot allocation: driver for mismatch between airline network and city needs? : the case of Rotterdam The Hague Airport

    NARCIS (Netherlands)

    van den Brandt, Marc; Mujica Mota, Miguel; Boosten, Geert; Hromádka, Martin

    2014-01-01

    Aviation increasingly faces capacity challenges exposing inefficiencies and shortcomings of aviation related processes and systems. The European slot allocation system was designed in an era with little to no capacity constraints, now resulting in regulations not fitting in today’s developments.

  14. 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.

  15. 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)

  16. 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)

  17. Harmonic oscillator in an elastic medium with a spiral dislocation

    Science.gov (United States)

    Maia, A. V. D. M.; Bakke, K.

    2018-02-01

    We investigate the behaviour of a two-dimensional harmonic oscillator in an elastic medium that possesses a spiral dislocation (an edge dislocation). We show that the Schrödinger equation for harmonic oscillator in the presence of a spiral dislocation can be solved analytically. Further, we discuss the effects of this topological defect on the confinement to a hard-wall confining potential. In both cases, we analyse if the effects of the topology of the spiral dislocation gives rise to an Aharonov-Bohm-type effect for bound states.

  18. Beyond slots and resources: grounding cognitive concepts in neural dynamics.

    Science.gov (United States)

    Johnson, Jeffrey S; Simmering, Vanessa R; Buss, Aaron T

    2014-08-01

    Research over the past decade has suggested that the ability to hold information in visual working memory (VWM) may be limited to as few as three to four items. However, the precise nature and source of these capacity limits remains hotly debated. Most commonly, capacity limits have been inferred from studies of visual change detection, in which performance declines systematically as a function of the number of items that participants must remember. According to one view, such declines indicate that a limited number of fixed-resolution representations are held in independent memory "slots." Another view suggests that such capacity limits are more apparent than real, but emerge as limited memory resources are distributed across more to-be-remembered items. Here we argue that, although both perspectives have merit and have generated and explained impressive amounts of empirical data, their central focus on the representations--rather than processes--underlying VWM may ultimately limit continuing progress in this area. As an alternative, we describe a neurally grounded, process-based approach to VWM: the dynamic field theory. Simulations demonstrate that this model can account for key aspects of behavioral performance in change detection, in addition to generating novel behavioral predictions that have been confirmed experimentally. Furthermore, we describe extensions of the model to recall tasks, the integration of visual features, cognitive development, individual differences, and functional imaging studies of VWM. We conclude by discussing the importance of grounding psychological concepts in neural dynamics, as a first step toward understanding the link between brain and behavior.

  19. Gambling goals predict chasing behavior during slot machine play.

    Science.gov (United States)

    Lister, Jamey J; Nower, Lia; Wohl, Michael J A

    2016-11-01

    The purpose of this study was to test the effect of gambling goals (i.e., gambling achievement-orientation) on chasing behavior (i.e., decision to chase, chasing spins) over and above known antecedents (e.g., problem gambling severity, winning money motivations, approach/avoidance motivation). Young adult gamblers (N=121) were provided $20 and invited to use those funds on a slot machine situated in an immersive virtual reality casino. Unbeknownst to participants, outcomes were manipulated such that a nominal amount of money was either won or lost (depending on experimental condition) after 30 spins. Before the 31st spin, participants were asked if they wished to continue play. If they agreed, all successive spin outcomes were a loss. This permitted an assessment of what factors influence a player's: (1) decision to chase and (2) the number of chasing spins played in the face of loss. Almost all participants (n=95, 78.5%) screened positive for problem gambling symptoms. The majority of gamblers decided to chase (n=67, 55.4%). In bivariate analyses, higher gambling goal and problem gambling severity scores (but not approach/avoidance nor 'loss/win' condition) were positively related to both forms of chasing. Gamblers 'motivated to win money' were more likely to decide to chase. In multivariate analyses, higher gambling goals best accounted for both forms of chasing independent of known antecedents. This study provides the first evidence that gambling goals can influence chasing. Implications for shaping responsible gambling approaches to be more consistent with motivations for play are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. 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)

  1. Effects of abnormal excitation on the dynamics of spiral waves

    Science.gov (United States)

    Min-Yi, Deng; Xue-Liang, Zhang; Jing-Yu, Dai

    2016-01-01

    The effect of physiological and pathological abnormal excitation of a myocyte on the spiral waves is investigated based on the cellular automaton model. When the excitability of the medium is high enough, the physiological abnormal excitation causes the spiral wave to meander irregularly and slowly. When the excitability of the medium is low enough, the physiological abnormal excitation leads to a new stable spiral wave. On the other hand, the pathological abnormal excitation destroys the spiral wave and results in the spatiotemporal chaos, which agrees with the clinical conclusion that the early after depolarization is the pro-arrhythmic mechanism of some anti-arrhythmic drugs. The mechanisms underlying these phenomena are analyzed. Project supported by the National Natural Science Foundation of China (Grant Nos. 11365003 and 11165004).

  2. Effects of semiclassical spiral fluctuations on hole dynamics

    Science.gov (United States)

    Hamad, I. J.; Manuel, L. O.; Trumper, A. E.

    2012-01-01

    We investigate the dynamics of a single hole coupled to the spiral fluctuations related to the magnetic ground states of the antiferromagnetic J1-J2-J3 Heisenberg model on a square lattice. Using exact diagonalization on finite size clusters and the self-consistent Born approximation in the thermodynamic limit, we find, as a general feature, a strong reduction of the quasiparticle weight along the spiral phases of the magnetic phase diagram. For an important region of the Brillouin zone the hole spectral functions are completely incoherent, whereas at low energies the spectral weight is redistributed on several irregular peaks. We find a characteristic value of the spiral pitch Q=(0.7,0.7)π, for which the available phase space for hole scattering is maximum. We argue that this behavior is due to the nontrivial interference of the magnon-assisted and the free-hopping mechanism for hole motion, characteristic of a hole coupled to semiclassical spiral fluctuations.

  3. Measurement and structure of spiral wave response functions

    Science.gov (United States)

    Dierckx, Hans; Verschelde, Henri; Panfilov, Alexander V.

    2017-09-01

    The rotating spiral waves that emerge in diverse natural and man-made systems typically exhibit a particle-like behaviour since their adjoint critical eigenmodes (response functions) are often seen to be localised around the spiral core. We present a simple method to numerically compute response functions for circular-core and meandering spirals by recording their drift response to many elementary perturbations. Although our method is computationally more expensive than solving the adjoint system, our technique is fully parallellisable, does not suffer from memory limitations and can be applied to experiments. For a cardiac tissue model with the linear spiral core, we find that the response functions are localised near the turning points of the trajectory.

  4. Data Fusion Tool for Spiral Bevel Gear Condition Indicator Data

    Science.gov (United States)

    Dempsey, Paula J.; Antolick, Lance J.; Branning, Jeremy S.; Thomas, Josiah

    2014-01-01

    Tests were performed on two spiral bevel gear sets in the NASA Glenn Spiral Bevel Gear Fatigue Test Rig to simulate the fielded failures of spiral bevel gears installed in a helicopter. Gear sets were tested until damage initiated and progressed on two or more gear or pinion teeth. During testing, gear health monitoring data was collected with two different health monitoring systems. Operational parameters were measured with a third data acquisition system. Tooth damage progression was documented with photographs taken at inspection intervals throughout the test. A software tool was developed for fusing the operational data and the vibration based gear condition indicator (CI) data collected from the two health monitoring systems. Results of this study illustrate the benefits of combining the data from all three systems to indicate progression of damage for spiral bevel gears. The tool also enabled evaluation of the effectiveness of each CI with respect to operational conditions and fault mode.

  5. Relative frequencies of supernovae versus properties of spiral hosts

    OpenAIRE

    Hakobyan, A. A.; Nazaryan, T. A.; Adibekyan, V. Zh.; Petrosian, A. R.; Aramyan, L. S.; Kunth, D.; Mamon, G. A.; de Lapparent, V.; Bertin, E.; Gomes, J. M.; Turatto, M.

    2013-01-01

    In this work, we present an analysis of SNe number ratios in spiral galaxies with different morphological subtypes, luminosities, sSFR, and metallicities, to provide important information about the physical properties of the progenitor populations.

  6. Simulating Fatigue Crack Growth in Spiral Bevel Pinion

    National Research Council Canada - National Science Library

    Ural, Ani

    2003-01-01

    .... To obtain a more detailed understanding of the contact between a cracked pinion tooth in mesh with an uncracked gear tooth, three-dimensional contact analyses were performed on a spiral bevel gear...

  7. Cassini discovers a kinematic spiral ring around Saturn.

    Science.gov (United States)

    Charnoz, S; Porco, C C; Déau, E; Brahic, A; Spitale, J N; Bacques, G; Baillie, K

    2005-11-25

    Since the time of the Voyager flybys of Saturn in 1980-1981, Saturn's eccentric F ring has been known to be accompanied on either side by faint strands of material. New Cassini observations show that these strands, initially interpreted as concentric ring segments, are in fact connected and form a single one-arm trailing spiral winding at least three times around Saturn. The spiral rotates around Saturn with the orbital motion of its constituent particles. This structure is likely the result of differential orbital motion stretching an initial cloud of particles scattered from the dense core of the F ring. Different scenarios of formation, implying ringlet-satellite interactions, are explored. A recently discovered moon candidate, S/2004 S6, is on an orbit that crosses the F-ring core at the intersection of the spiral with the ring, which suggests a dynamical connection between S/2004 S6 and the spiral.

  8. Meter-Scale Atmospheric-Pressure Microwave Plasma Using Sub-Millimeter-Gap Slot

    Science.gov (United States)

    Toyoda, Hirotaka

    2013-09-01

    Atmospheric-pressure pulsed plasmas have been given much attention because of its various possibilities for industrial applications such as surface wettability control, sterilization and so on. Among various atmospheric-pressure plasma sources, microwave plasma that is produced inside waveguide-slots is attractive because high-density plasma up to 1015 cm-3 can be easily produced along very long waveguide with light-weight and rather simple antenna configuration. So far, we have investigated plasma production inside slot of the waveguide and in this talk, elongation of the plasma up to meter-scale with newly-designed plasma source will be presented. In this study, two types of antennas are proposed to elongate the atmospheric-pressure microwave plasma. Firstly, array-structured slot design with a closed-end waveguide is adopted using X-band microwave (10 GHz). In this structure, slot antennas with a total number of more than 40 are positioned with λg/2-pitch along ~1m waveguide so as to utilize standing wave inside the waveguide and to increase the electric field inside the slot. By optimizing the antenna design, arrayed microwave plasmas are successfully produced along ~1m-length waveguide. The arrayed-slot structure, however, the plasma is not completely uniform along the waveguide and plasma density drastically decreases between two adjacent slots. To solve this, an alternative type of antenna that is free from the standing wave effect is designed. In this new-type antenna, travelling wave inside the waveguide with no reflection wave is realized by a combination of a microwave circulator and a ring-structured waveguide. By this transmission line, microwave power flows only to one direction and the average microwave power becomes spatially uniform along the waveguide. By using a single but very long slot up to several tens cm, very uniform plasma is produced along the slot. The result strongly suggests easy scale-up of the plasma source more than one meter that

  9. Dosimetry in dental radiology. Dentascan spiral CT versus panoramic radiography

    International Nuclear Information System (INIS)

    Villari, N.; Stecco, A.; Zatelli, G.

    1999-01-01

    The study compares the doses absorbed by the dentomaxillary area in spiral CT and panoramic examinations. The dose measurements demonstrate that patients receive smaller doses with panoramic radiography than with spiral CT with Dentascan. After following for some variations from instrumental differences, they are in substantial agreement with literature data. Further investigations are needed considering the radiobiological risk related to the growing spread of Dentascan examinations [it

  10. 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

  11. 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

  12. 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)

  13. Effect of Slot Antenna Structure on Production of Planar Surface Wave Plasmas

    Science.gov (United States)

    Nagatsu, M.; Ito, A.; Morita, S.; Ghanashev, I.; Sugai, H.; Toyoda, N.

    1998-10-01

    Characteristics of planar surface wave plasmas (SWP) produced by a 2.45 GHz microwave via slot antennas have been studied(M. Nagatsu et al Plasma Sources Sci. Technol.) 6 (1997) 427.^,(H. Sugai et al Plasma Sources Sci. Technol.) 7 (1998) 192.. Effect of antenna-plasma coupling was investigated for various slot antennas by measuring plasma characteristics against an incident microwave power. Four types of slot antenna, that is, inclined, vertical, transverse and radial slots, were tested. At high pressure of say 1 Torr, optical emission patterns of various TM modes were observed in respective slots as expected by theoretical dispersion relationsfootnote I. Ghanashev et al Jpn. J. Appl. Phys. 36 (1997) 337.. At low pressure of 10 mTorr, uniformly broadened plasma emission was observed regardless of the antenna structure. An attempt of reducing dielectric window area for vacuum sealing has been made to develop economical etching or CVD plasma sources with less impurities(S. Morita et al Jpn. J. Appl. Phys.) 37 (1998) L468.. Recent results of SWP experiments in a larger chamber using 2.45 GHz and 915 MHz waves will be also given. This work was supported by Toshiba Corp., Nissin Inc, and also by a Grant-in-Aid for Science Research from the Ministry of Education, Science, Sports and Culture in Japan.

  14. Dynamic Allocation of SPM Based on Time-Slotted Cache Conflict Graph for System Optimization

    Science.gov (United States)

    Wu, Jianping; Ling, Ming; Zhang, Yang; Mei, Chen; Wang, Huan

    This paper proposes a novel dynamic Scratch-pad Memory allocation strategy to optimize the energy consumption of the memory sub-system. Firstly, the whole program execution process is sliced into several time slots according to the temporal dimension; thereafter, a Time-Slotted Cache Conflict Graph (TSCCG) is introduced to model the behavior of Data Cache (D-Cache) conflicts within each time slot. Then, Integer Nonlinear Programming (INP) is implemented, which can avoid time-consuming linearization process, to select the most profitable data pages. Virtual Memory System (VMS) is adopted to remap those data pages, which will cause severe Cache conflicts within a time slot, to SPM. In order to minimize the swapping overhead of dynamic SPM allocation, a novel SPM controller with a tightly coupled DMA is introduced to issue the swapping operations without CPU's intervention. Last but not the least, this paper discusses the fluctuation of system energy profit based on different MMU page size as well as the Time Slot duration quantitatively. According to our design space exploration, the proposed method can optimize all of the data segments, including global data, heap and stack data in general, and reduce the total energy consumption by 27.28% on average, up to 55.22% with a marginal performance promotion. And comparing to the conventional static CCG (Cache Conflicts Graph), our approach can obtain 24.7% energy profit on average, up to 30.5% with a sight boost in performance.

  15. Ka-Band Slot-Microstrip-Covered and Waveguide-Cavity-Backed Monopulse Antenna Array

    Directory of Open Access Journals (Sweden)

    Li-Ming Si

    2014-01-01

    Full Text Available A slot-microstrip-covered and waveguide-cavity-backed monopulse antenna array is proposed for high-resolution tracking applications at Ka-band. The monopulse antenna array is designed with a microstrip with 2×32 slots, a waveguide cavity, and a waveguide monopulse comparator, to make the structure simple, reduce the feeding network loss, and increase the frequency bandwidth. The 2×32 slot-microstrip elements are formed by a metal clad dielectric substrate and slots etched in the metal using the standard printed circuit board (PCB process with dimensions of 230 mm  ×  10 mm. The proposed monopulse antenna array not only maintains the advantages of the traditional waveguide slot antenna array, but also has the characteristics of wide bandwidth, high consistence, easy of fabrication, and low cost. From the measured results, it exhibits good monopulse characteristics, including the following: the maximum gains of sum pattern are greater than 24 dB, the 3 dB beamwidth of sum pattern is about 2.2 degrees, the sidelobe levels of the sum pattern are less than −18 dB, and the null depths of the difference pattern are less than −25 dB within the operating bandwidth between 33.65 GHz and 34.35 GHz for VSWR ≤ 2.

  16. Joint slot allocation and dynamic pricing of container sea–rail multimodal transportation

    Directory of Open Access Journals (Sweden)

    Di Liu

    2015-06-01

    Full Text Available The container sea–rail multimodal transport system faces complex challenges with demand uncertainties for joint slot allocation and dynamic pricing. The challenge is formulated as a two-stage optimal model based on revenue management (RM as actual slots sale of multi-node container sea–rail multimodal transport usually includes contract sale to large shippers and free sale to scattered shippers. First stage in the model utilizes an origin-destination control approach, formulated as a stochastic integer programming equation, to settle long-term slot allocation in the contract market and empty container allocation. Second stage in the model is formulated as a stochastic nonlinear programming equation to solve a multiproduct joint dynamic pricing and inventory control problem for price settling and slot allocation in each period of free market. Considering the random nature of demand, the methods of chance constrained programming and robust optimization are utilized to transform stochastic models into deterministic models. A numerical experiment is presented to verify the availability of models and solving methods. Results of considering uncertain/certain demand are compared, which show that the two-stage optimal strategy integrating slot allocation with dynamic pricing considering random demand is revealed to increase the revenue for multimodal transport operators (MTO while concurrently satisfying shippers' demand. Research resulting from this paper will contribute to the theory and practice of container sea–rail multimodal transport revenue management and provide a scientific decision-making tool for MTO.

  17. Nonlinear theory of a cyclotron autoresonance maser (CARM) amplifier with outer-slotted-coaxial waveguide

    International Nuclear Information System (INIS)

    Qiu Chunrong; Ouyang Zhengbiao; Zhang Shichang; Zhang Huibo; Jin Jianbo; Lai Yingxin

    2005-01-01

    A self-consistent nonlinear theory for the outer-slotted-coaxial-waveguide cyclotron autoresonance maser (CARM) amplifier is presented, which includes the characteristic equation of the wave, coupling equation of the wave with the relativistic electron beam and the simulation model. The influences of the magnetic field, the slot depth and width are investigated. The interesting characteristic of the device is that the mode competition can be efficiently suppressed by slotting the outer wall of the coaxial waveguide. A typical example is given by the theoretical design of a 137 GHz outer-slotted-coaxial-waveguide CARM amplifier by utilizing an electron beam with a voltage of 90 kV, current of 50 A, velocity pitch angle of 0.85 and a magnetic field of 43.0 kG. The nonlinear simulation predicts a power of 467.9 kW, an electronic efficiency of 10.4% and a saturated gain of 46.7 dB, if the electron beam has no velocity spread. However, the axial velocity spread deteriorates the device; for example, if the axial velocity spread is 2%, the peak power decreases to 332.4 kW with an efficiency of 7.4% and a saturated gain of 45.22 dB. Simulation shows that the efficiency of the outer-slotted-coaxial-waveguide CARM amplifier may be increased from 10.4% to 29.6% by tapering the magnetic field

  18. A model of gas flow with friction in a slotted seal

    Directory of Open Access Journals (Sweden)

    Joachimiak Damian

    2016-09-01

    Full Text Available The paper discusses thermodynamic phenomena accompanying the flow of gas in a slotted seal. The analysis of the gas flow has been described based on an irreversible adiabatic transformation. A model based on the equation of total enthalpy balance has been proposed. The iterative process of the model aims at obtaining such a gas temperature distribution that will fulfill the continuity equation. The model allows for dissipation of the kinetic energy into friction heat by making use of the Blasius equation to determine the friction coefficient. Within the works, experimental research has been performed of the gas flow in a slotted seal of slot height 2 mm. Based on the experimental data, the equation of local friction coefficient was modified with a correction parameter. This parameter was described with the function of pressure ratio to obtain a mass flow of the value from the experiment. The reason for taking up of this problem is the absence of high accuracy models for calculating the gas flow in slotted seals. The proposed model allows an accurate determination of the mass flow in a slotted seal based on the geometry and gas initial and final parameters.

  19. Spiralizations and tropisms in Arabidopsis roots.

    Science.gov (United States)

    Migliaccio, F; Piconese, S

    2001-12-01

    When Arabidopsis seedlings are grown on a hard-agar plate, their primary roots show characteristic spiralling movements, apparent as waves, coils and torsions, together with a slanting toward the right-hand side. All these movements are believed to be the result of three different processes acting on the roots: circumnutation, positive gravitropism and negative thigmotropism. The basic movement of the roots is described as that of a growing right-handed helix, which, because of the root tip hitting the agar plate, is continuously switched from the right-hand to the left-hand of the growth direction, and vice versa. This movement also produces a slanting root-growth direction toward the right-hand because of the incomplete waves made by the right-handed root to the left-hand. By contrast, the torsions seen in the coils and waves are interpreted as artefacts that form as an adaptation of the three-dimensional root helix to the flat two-dimensional agar surface.

  20. Noncontrast peripheral MRA with spiral echo train imaging.

    Science.gov (United States)

    Fielden, Samuel W; Mugler, John P; Hagspiel, Klaus D; Norton, Patrick T; Kramer, Christopher M; Meyer, Craig H

    2015-03-01

    To develop a spin echo train sequence with spiral readout gradients with improved artery-vein contrast for noncontrast angiography. Venous T2 becomes shorter as the echo spacing is increased in echo train sequences, improving contrast. Spiral acquisitions, due to their data collection efficiency, facilitate long echo spacings without increasing scan times. Bloch equation simulations were performed to determine optimal sequence parameters, and the sequence was applied in five volunteers. In two volunteers, the sequence was performed with a range of echo times and echo spacings to compare with the theoretical contrast behavior. A Cartesian version of the sequence was used to compare contrast appearance with the spiral sequence. Additionally, spiral parallel imaging was optionally used to improve image resolution. In vivo, artery-vein contrast properties followed the general shape predicted by simulations, and good results were obtained in all stations. Compared with a Cartesian implementation, the spiral sequence had superior artery-vein contrast, better spatial resolution (1.2 mm(2) versus 1.5 mm(2) ), and was acquired in less time (1.4 min versus 7.5 min). The spiral spin echo train sequence can be used for flow-independent angiography to generate three-dimensional angiograms of the periphery quickly and without the use of contrast agents. © 2014 Wiley Periodicals, Inc.

  1. Mechanics and spiral formation in the rat cornea.

    Science.gov (United States)

    Mohammad Nejad, T; Iannaccone, S; Rutherford, W; Iannaccone, P M; Foster, C D

    2015-01-01

    During the maturation of some mammals such as mice and rats, corneal epithelial cells tend to develop into patterns such as spirals over time. A better understanding of these patterns can help to understand how the organ develops and may give insight into some of the diseases affecting corneal development. In this paper, a framework for explaining the development of the epithelial cells forming spiral patterns due to the effect of tensile and shear strains is proposed. Using chimeric animals, made by combining embryonic cells from genetically distinguishable strains, we can observe the development of patterns in the cornea. Aggregates of cell progeny from one strain or the other called patches form as organs and tissue develop. The boundaries of these patches are fitted with logarithmic spirals on confocal images of adult rat corneas. To compare with observed patterns, we develop a three-dimensional large strain finite element model for the rat cornea under intraocular pressure to examine the strain distribution on the cornea surface. The model includes the effects of oriented and dispersed fibrils families throughout the cornea and a nearly incompressible matrix. Tracing the directions of critical strain vectors on the cornea surface leads to spiral-like curves that are compared to the observed logarithmic spirals. Good agreement between the observed and numerical curves supports the proposed assumption that shear and tensile strains facilitate sliding of epithelial cells to develop spiral patterns.

  2. Improved MRI thermometry with multiple-echo spirals.

    Science.gov (United States)

    Marx, Michael; Butts Pauly, Kim

    2016-09-01

    Low-bandwidth PRF shift thermometry is used to guide HIFU ablation treatments. Low sampling bandwidth is needed for high signal-to-noise ratio with short acquisition times, but can lead to off-resonance artifacts. In this work, improved multiple-echo thermometry is presented that allows for high bandwidth and reduced artifacts. It is also demonstrated with spiral sampling, to improve the trade-off between resolution, speed, and measurement precision. Four multiple-echo thermometry sequences were tested in vivo, one using two-dimensional Fourier transform (2DFT) sampling and three using spirals. The spiral sequences were individually optimized for resolution, for speed, and for precision. Multifrequency reconstruction was used to correct for off-resonance spiral artifacts. Additionally, two different multiecho temperature reconstructions were compared. Weighted combination of per-echo phase differences gave significantly better precision than least squares off-resonance estimation. Multiple-echo 2DFT sequence obtained precision similar to single-echo 2DFT, while greatly increasing sampling bandwidth. The multiecho spiral acquisitions achieved 2× better resolution, 2.9× better uncertainty, or 3.4× faster acquisition time, without negatively impacting the other two design parameters as compared to single-echo 2DFT. Multiecho spiral thermometry greatly improves the capabilities of temperature monitoring, and could improve transcranial treatment monitoring capabilities. Magn Reson Med 76:747-756, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  3. Spiral instabilities in media supporting complex oscillations under periodic forcing

    Science.gov (United States)

    Gao, Qingyu; Li, Jun; Zhang, Kailong; Epstein, Irving R.

    2009-09-01

    The periodically forced Brusselator model displays temporal mixed-mode and quasiperiodic oscillations, period doubling, and chaos. We explore the behavior of such media as reaction-diffusion systems for investigating spiral instabilities. Besides near-core breakup and far-field breakup resulting from unstable modes in the radial direction or Doppler-induced instability (destabilization of the core's location), the observed complex phenomena include backfiring, spiral regeneration, and amplitude modulation from line defects. Amplitude modulation of spirals can evolve to chambered spirals resembling those found in nature, such as pine cones and sunflowers. When the forcing amplitude is increased, the spiral-tip meander evolves from simple rotation to complex petals, corresponding to transformation of the local dynamics from simple oscillations to mixed-mode, period-2, and quasiperiodic oscillations. The number of petals is related to the complexity of the mixed-mode oscillations. Spiral turbulence, standing waves, and homogeneous synchronization permeate the entire system when the forcing amplitude is further increased.

  4. 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...

  5. 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...

  6. A new method for the design of slot antenna arrays: Theory and experiment

    KAUST Repository

    Clauzier, Sebastien

    2016-04-10

    The present paper proposes and validates a new general design methodology that can be used to automatically find proper positions and orientations of waveguide-based radiating slots capable of realizing any given radiation beam profile. The new technique combines basic radiation theory and waveguide propagation theory in a novel analytical model that allows the prediction of the radiation characteristics of generic slots without the need to perform full-wave numerical solution. The analytical model is then used to implement a low-cost objective function within a global optimization scheme (here genetic algorithm.) The algorithm is then deployed to find optimum positions and orientations of clusters of radiating slots cut into the waveguide surface such that any desired beam pattern can be obtained. The method is verified using both full-wave numerical solution and experiment.

  7. Pressure distribution over NACA 23012 airfoil with a slotted and a split flap

    Science.gov (United States)

    Harris, Thomas A; Lowry, John G

    1941-01-01

    A pressure-distribution investigation has been conducted in the NACA 4 by 6-foot vertical wind tunnel to determine the air loads on an NACA 23012 airfoil in combination with a 25.66-percent-chord slotted flap and a 20-percent-chord split flap. Pressures were measured on both the upper and the lower surfaces of the main airfoil and the flaps for several angles of attack and at several flap settings. The data, presented as pressure diagrams and as graphs of the section coefficients for the flap alone and for the airfoil-flap combinations, are applicable to rib and flap design for a combination of a thick airfoil and a slotted or a split flap. The results of previous tests of a NACA 23012 airfoil with a slotted flap are compared with the present results.

  8. Novel Dual-band Slot Antenna Design for Bluetooth and UWB Applications

    Science.gov (United States)

    Huang, Hai-Yan; Shao, Wei; Wang, Bing-Zhong; Ma, Xiao-Liang

    2014-05-01

    A novel technique to introduce an additional low frequency band to compact ultra wideband (UWB) slot antennas is proposed in this paper. To get an additional Bluetooth band, a parasitic strip is mounted on the back side of the slot edge. Because of the interaction of the strip and the slot edge, the Bluetooth band can be obtained while a notch band between the Bluetooth band and UWB band also appears. Two types of feeding, coplanar waveguide and microstrip line, are investigated. The proposed antennas are both fabricated on a low-cost FR4 substrate and have compact size (24 mm × 28 mm × 1 mm). The good agreement between measured and simulated results verifies our design.

  9. An Open Slot Antenna with Bandwidth Extension for WLAN/UWB Applications

    Directory of Open Access Journals (Sweden)

    Jing-Ya Deng

    2015-01-01

    Full Text Available An open slot antenna with extended bandwidth for WLAN and UWB applications is proposed. The radiating structure is composed of a rectangular microstrip patch antenna exciting an L-shaped slot etched on the ground plane. The feed position is optimized to get better impedance match for the higher range of the UWB spectrum, while a step in the slot, realized in the ground plane, is employed to extend the lower limit of the bandwidth so as to cover the 2.4 GHz WLAN frequency band. Using these design solutions the antenna bandwidth is successfully extended to 140% so as to cover both the WLAN and the UWB spectrum.

  10. Benefits and unexpected artifacts of biplanar digital slot-scanning imaging in children.

    Science.gov (United States)

    Blumer, Steven L; Dinan, David; Grissom, Leslie E

    2014-07-01

    Biplanar digital slot-scanning allows for relatively low-dose orthopedic imaging, an advantage in imaging children given the growing concerns regarding radiosensitivity. We have used this system for approximately 1 year for orthopedic imaging of the spine and lower extremities. We have noted advantages of using the digital slot-scanning system when compared with computed radiographic and standard digital radiographic imaging systems, but we also found unexpected but common imaging artifacts that are the direct result of the imaging method and that have not been reported. This pictorial essay serves to familiarize radiologists with the advantages of the digital slot-scanning system as well as imaging artifacts common with this new technology.

  11. The Impact of the Rotor Slot Number on the Behaviour of the Induction Motor

    Directory of Open Access Journals (Sweden)

    Konstantinos N. Gyftakis

    2013-01-01

    Full Text Available The impact of the rotor slot number selection on the induction motors is investigated. Firstly, analytical equations will reveal the spatial harmonic index of the air gap magnetic flux density, connected to the geometrical features and the saturation of the induction motor. Then, six motors with different rotor slot numbers are simulated and studied with FEM. The stator is identical in all motors. The motors are examined under time-harmonic analysis at starting and at 1440 rpm. Their electromagnetic characteristics, such as electromagnetic torque, stator current, and magnetic flux density, are extracted and compared to each other. The analysis will reveal that the proper rotor slot number selection has a strong impact on the induction motor performance.

  12. Wave Propagation in a coaxial waveguide with a periodic slot array

    CERN Document Server

    Alesini, D; Garganese, C; Migliorati, M; Palumbo, L

    2001-01-01

    In this paper we present the numerical and experimental study of the electromagnetic elds that propagate in a coaxial waveguide having periodic slots in the inner conductor. The aim of the work is to estimate the e ects of the holes on the phase velocity of the eld propagating in structures like the LHC liner, and to which extent these elds can be considered synchronous with the generating beam. To this end we have performed a numerical analysis by using the MAFIA simulation code, and have obtained, for a given geometry, the ampli- tude of the slowing down of the phase velocity due to the presence of the slot array. We have then performed a set of measurements of this e ect on a simple coaxial resonator, measuring the shift of the resonance frequencies produced by the slots. This shift, related to the phase velocity, has been compared with the results obtained with the simulations.

  13. Advanced hybrid query tree algorithm based on slotted backoff mechanism in RFID

    Directory of Open Access Journals (Sweden)

    XIE Xiaohui

    2013-12-01

    Full Text Available The merits of performance quality for a RFID system are determined by the effectiveness of tag anti-collision algorithm.Many algorithms for RFID system of tag identification have been proposed,but they all have obvious weaknesses,such as slow speed of identification,unstable and so on.The existing algorithms can be divided into two groups,one is based on ALOHA and another is based on query tree.This article is based on the hybrid query tree algorithm,combined with a slotted backoff mechanism and a specific encoding (Manchester encoding.The number of value“1” in every three consecutive bits of tags is used to determine the tag response time slots,which will greatly reduce the time slot of the collision and improve the recognition efficiency.

  14. Crossed-Slot Cavity-Backed Antenna with Improved Hemispherical Coverage

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav; Østergaard, Allan

    2005-01-01

    The paper presents the results of the investigation of the crossed-slot cavity-backed antenna with the complementary crossed electric dipoles added to compensate the circularly polarized (CP) radiation pattern degradation near the horizon. Dependences of the radiation characteristics of the modif......The paper presents the results of the investigation of the crossed-slot cavity-backed antenna with the complementary crossed electric dipoles added to compensate the circularly polarized (CP) radiation pattern degradation near the horizon. Dependences of the radiation characteristics...... of the modified crossed-slot cavity-backed antenna on the length, width and height of the crossed electric dipoles are shown. Effects of a finite size ground plane are taken into account due to a full wave electromagnetic analysis software utilized in the parametrical investigations. Simulated and measured...

  15. Semi-automatic parking slot marking recognition for intelligent parking assist systems

    Directory of Open Access Journals (Sweden)

    Ho Gi Jung

    2014-01-01

    Full Text Available This paper proposes a semi-automatic parking slot marking-based target position designation method for parking assist systems in cases where the parking slot markings are of a rectangular type, and its efficient implementation for real-time operation. After the driver observes a rearview image captured by a rearward camera installed at the rear of the vehicle through a touchscreen-based human machine interface, a target parking position is designated by touching the inside of a parking slot. To ensure the proposed method operates in real-time in an embedded environment, access of the bird's-eye view image is made efficient: image-wise batch transformation is replaced with pixel-wise instantaneous transformation. The proposed method showed a 95.5% recognition rate in 378 test cases with 63 test images. Additionally, experiments confirmed that the pixel-wise instantaneous transformation reduced execution time by 92%.

  16. Rapid Prototyping of Slot Die Devices for Roll to Roll Production of EL Fibers.

    Science.gov (United States)

    Bellingham, Alyssa; Bromhead, Nicholas; Fontecchio, Adam

    2017-05-29

    There is a growing interest in fibers supporting optoelectrical properties for textile and wearable display applications. Solution-processed electroluminescent (EL) material systems can be continuously deposited onto fiber or yarn substrates in a roll-to-roll process, making it easy to scale manufacturing. It is important to have precise control over layer deposition to achieve uniform and reliable light emission from these EL fibers. Slot-die coating offers this control and increases the rate of EL fiber production. Here, we report a highly adaptable, cost-effective 3D printing model for developing slot dies used in automatic coating systems. The resulting slot-die coating system enables rapid, reliable production of alternating current powder-based EL (ACPEL) fibers and can be adapted for many material systems. The benefits of this system over dip-coating for roll-to-roll production of EL fibers are demonstrated in this work.

  17. Athermal Wavelength Characteristics of Si Slot Ring Resonator Embedded with Benzocyclobutene for Optoelectronic Integrated Circuits

    Science.gov (United States)

    Yuki Atsumi,; Keita Inoue,; Nobuhiko Nishiyama,; Shigehisa Arai,

    2010-05-01

    An athermal Si-slot-waveguide ring resonator embedded with benzocyclobutene (BCB), a low-k material used in electronics, was proposed. By controlling the width of the BCB-filled gap to 90 nm, the temperature coefficient of equivalent index of a Si slot waveguide could be reduced to 3.70× 10-6, which is two orders of magnitude smaller than that of a conventional Si waveguide. The dependences of peak wavelength shift on temperature in the fabricated devices of a conventional Si wire waveguide with SiO2 cladding, Si wire waveguide with BCB cladding, and Si slot waveguide with BCB cladding were 26, 17, and -0.6 pm/K, respectively.

  18. Effect of Slotted Anode on Gas Bubble Behaviors in Aluminum Reduction Cell

    Science.gov (United States)

    Sun, Meijia; Li, Baokuan; Li, Linmin; Wang, Qiang; Peng, Jianping; Wang, Yaowu; Cheung, Sherman C. P.

    2017-12-01

    In the aluminum reduction cells, gas bubbles are generated at the bottom of the anode which eventually reduces the effective current contact area and the system efficiency. To encourage the removal of gas bubbles, slotted anode has been proposed and increasingly adopted by some industrial aluminum reduction cells. Nonetheless, the exact gas bubble removal mechanisms are yet to be fully understood. A three-dimensional (3D) transient, multiphase flow mathematical model coupled with magnetohydrodynamics has been developed to investigate the effect of slotted anode on the gas bubble movement. The Eulerian volume of fluid approach is applied to track the electrolyte (bath)-molten aluminum (metal) interface. Meanwhile, the Lagrangian discrete particle model is employed to handle the dynamics of gas bubbles with considerations of the buoyancy force, drag force, virtual mass force, and pressure gradient force. The gas bubble coalescence process is also taken into account based on the O'Rourke's algorithm. The two-way coupling between discrete bubbles and fluids is achieved by the inter-phase momentum exchange. Numerical predictions are validated against the anode current variation in an industrial test. Comparing the results using slotted anode with the traditional one, the time-averaged gas bubble removal rate increases from 36 to 63 pct; confirming that the slotted anode provides more escaping ways and shortens the trajectories for gas bubbles. Furthermore, the slotted anode also reduces gas bubble's residence time and the probability of coalescence. Moreover, the bubble layer thickness in aluminum cell with slotted anode is reduced about 3.5 mm (17.4 pct), so the resistance can be cut down for the sake of energy saving and the metal surface fluctuation amplitude is significantly reduced for the stable operation due to the slighter perturbation with smaller bubbles.

  19. Clear New View of a Classic Spiral

    Science.gov (United States)

    2010-05-01

    ESO is releasing a beautiful image of the nearby galaxy Messier 83 taken by the HAWK-I instrument on ESO's Very Large Telescope (VLT) at the Paranal Observatory in Chile. The picture shows the galaxy in infrared light and demonstrates the impressive power of the camera to create one of the sharpest and most detailed pictures of Messier 83 ever taken from the ground. The galaxy Messier 83 (eso0825) is located about 15 million light-years away in the constellation of Hydra (the Sea Serpent). It spans over 40 000 light-years, only 40 percent the size of the Milky Way, but in many ways is quite similar to our home galaxy, both in its spiral shape and the presence of a bar of stars across its centre. Messier 83 is famous among astronomers for its many supernovae: vast explosions that end the lives of some stars. Over the last century, six supernovae have been observed in Messier 83 - a record number that is matched by only one other galaxy. Even without supernovae, Messier 83 is one of the brightest nearby galaxies, visible using just binoculars. Messier 83 has been observed in the infrared part of the spectrum using HAWK-I [1], a powerful camera on ESO's Very Large Telescope (VLT). When viewed in infrared light most of the obscuring dust that hides much of Messier 83 becomes transparent. The brightly lit gas around hot young stars in the spiral arms is also less prominent in infrared pictures. As a result much more of the structure of the galaxy and the vast hordes of its constituent stars can be seen. This clear view is important for astronomers looking for clusters of young stars, especially those hidden in dusty regions of the galaxy. Studying such star clusters was one of the main scientific goals of these observations [2]. When compared to earlier images, the acute vision of HAWK-I reveals far more stars within the galaxy. The combination of the huge mirror of the VLT, the large field of view and great sensitivity of the camera, and the superb observing conditions

  20. Cogging Torque Reduction by Slot-Opening Shift for Permanent Magnet Machines

    DEFF Research Database (Denmark)

    Liu, Ting; Huang, Shoudao; Gao, Jian

    2013-01-01

    In this paper, an effective cogging torque reduction method based on shifting the slot-openings is presented. Stator teeth are divided into groups and proper slot-opening shift is applied for each group. The cogging torque can then be greatly reduced while the back-EMF waveforms remain symmetrica....... No additional back-EMF harmonic components will be introduced by this method. Analytical analysis revealing the working principle of this method is given, which gives a clear guide about how this method may be applied to different permanent magnet machines....

  1. A Miniaturized Dual-Mode Bandpass Filter Using Slot Spurline Technique

    Directory of Open Access Journals (Sweden)

    Haiwen Liu

    2013-01-01

    Full Text Available A miniaturized dual-mode bandpass filter (BPF with elliptic function response using slot spurline is designed in this paper. The slot spurline can not only splits the degenerate modes but also determine the type of filter characteristic (Chebyshev or elliptic. To miniaturize the resonator, four sagittate stubs are proposed. For demonstration purpose, a BPF operating at 5.75 GHz for WLAN application was designed, fabricated, and measured. The measured results are in good agreement with the full-wave simulation results.

  2. All-optical logic gates in plasmonic metal-insulator-metal nanowaveguide with slot cavity resonator

    Science.gov (United States)

    Dolatabady, Alireza; Granpayeh, Nosrat

    2017-04-01

    We demonstrate the compact all-optical logic XOR and OR gates in subwavelength plasmonic metal-insulator-metal waveguides with slot cavity resonators, especially for telecommunication wavelengths, with an extinction ratio of 25 dB, which can provide nanoscale logic integrated circuits. The gates behavior is based on suppression or enhancement of resonant modes in a slot cavity resonator induced by a change in position of input ports. The performance of the gates is discussed analytically and verified by the numerical method of finite-difference time-domain (FDTD).

  3. Compact broadband circularly polarised slot antenna for universal UHF RFID readers

    DEFF Research Database (Denmark)

    Xu, Bo; Zhang, Shuai; Liu, Yusha

    2015-01-01

    A compact broadband circularly polarised (CP) slot antenna is designed for universal ultra-high-frequency (UHF) radio frequency identification (RFID) readers. The antenna consists of an L-shaped metal strip and a square-slot-loaded ground plane with four tuning stubs. The total size is 100 mm×100mm......×1.6 mm. The measured –10 dB impedance bandwidth is 40.7% (772–1166 MHz) and the measured 3 dB axial ratio (AR) bandwidth is 13.9% (840–965 MHz). Both the impedance and AR bandwidth cover the worldwide UHF RFID band....

  4. Theoretical and experimental study of microstrip-to-slot line uniplanar transition

    Science.gov (United States)

    Yook, Jong-Gwan; Dib, Nihad I.; Katehi, Linda P. B.; Simons, Rainee N.; Taub, Susan R.

    1994-05-01

    Recent advances in MMCI technology make it possible to construct transitions from CPW-to-microstrip with via hole, microstrip-to-slot line and microshield line-to-CPW all of which have potential applications in the feed network of antennas. In this study we investigate the characteristics of the microstrip-to-slot line uniplanar transition using the finite element methods (FEM) and finite difference time domain (FDTD) techniques, and compared the theoretical results with the measurements. In both cases, the results agree with the measurements within a few percent.

  5. Simple gambling or sophisticated gaming? : applying game analysis methods to modern video slot machine games

    OpenAIRE

    Leppäsalko, Tero

    2017-01-01

    Slot machine games have become the most popular form of gambling worldwide. In Finland, their pervasiveness in public spaces and popularity makes them one of the most common form of gaming. However, in game studies, gambling games are often regarded as borderline games due to the player’s lack of control. In this thesis I ask whether modern video slot machine games can be considered as games and if so, what similarities there are between them and contemporary video games. To find out if m...

  6. Dual-slot antennas for microwave tissue heating: parametric design analysis and experimental validation.

    Science.gov (United States)

    Brace, Christopher L

    2011-07-01

    Design and validate an efficient dual-slot coaxial microwave ablation antenna that produces an approximately spherical heating pattern to match the shape of most abdominal and pulmonary tumor targets. A dual-slot antenna geometry was utilized for this study. Permutations of the antenna geometry using proximal and distal slot widths from 1 to 10 mm separated by 1-20 mm were analyzed using finite-element electromagnetic simulations. From this series, the most optimal antenna geometry was selected using a two-term sigmoidal objective function to minimize antenna reflection coefficient and maximize the diameter-to-length aspect ratio of heat generation. Sensitivities to variations in tissue properties and insertion depth were also evaluated in numerical models. The most optimal dual-slot geometry of the parametric analysis was then fabricated from semirigid coaxial cable. Antenna reflection coefficients at various insertion depths were recorded in ex vivo bovine livers and compared to numerical results. Ablation zones were then created by applying 50 W for 2-10 min in simulations and ex vivo livers. Mean zone diameter, length, aspect ratio, and reflection coefficients before and after heating were then compared to a conventional monopole antenna using ANOVA with post-hoc t-tests. Statistical significance was indicated for P designs utilized a proximal slot width of 1 mm, distal slot width of 4 mm +/- 1 mm and separation of 8 mm +/- 1 mm. These designs were characterized by an active choking mechanism that focused heating to the distal tip of the antenna. A dual-band resonance was observed in the most optimal design, with a minimum reflection coefficient of -20.9 dB at 2.45 and 1.25 GHz. Total operating bandwidth was greater than 1 GHz, but the desired heating pattern was achieved only near 2.45 GHz. As a result, antenna performance was robust to changes in insertion depth and variations in relative permittivity of the surrounding tissue medium. In both simulations and

  7. Efficient electro-optic modulation in low-loss graphene-plasmonic slot waveguides

    DEFF Research Database (Denmark)

    Ding, Y; Guan, Xiaowei; Zhu, X

    2017-01-01

    , and the devices are fully integrated in the silicon-on-insulator platform. By advantageously exploiting low-loss plasmonic slot-waveguide modes, which weakly leak into a substrate while featuring strong fields within the two-layer-graphene covered slots in metals, we successfully achieve a tunability of 0.13 d......B μm-1 for our fabricated graphene-plasmonic waveguide devices with extremely low insertion loss, which outperforms previously reported graphene-plasmonic devices. Our results highlight the potential of graphene plasmonic leaky-mode hybrid waveguides to realize active ultra-compact devices...

  8. 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.

  9. The Globular Cluster System of the Spiral Galaxy NGC 7814

    Science.gov (United States)

    Rhode, Katherine L.; Zepf, Stephen E.

    2003-11-01

    We present the results of a wide-field photometric study of the globular cluster (GC) system of the edge-on Sab spiral NGC 7814. This is the first spiral to be fully analyzed from our survey of the GC systems of a large sample of galaxies beyond the Local Group. NGC 7814 is of particular interest because a previous study estimated that it has 500-1000 GCs, giving it the largest specific frequency (SN) known for a spiral. Understanding this galaxy's GC system is important in terms of our understanding of the GC populations of spirals in general and has implications for the formation of massive galaxies. We observed the galaxy in BVR filters with the WIYN 3.5 m telescope and used image classification and three-color photometry to select GC candidates. We also analyzed archival Hubble Space Telescope (HST) Wide Field Planetary Camera 2 images of NGC 7814, both to help quantify the contamination level of the WIYN GC candidate list and to detect GCs in the inner part of the galaxy halo. Combining HST data with high-quality ground-based images allows us to trace the entire radial extent of this galaxy's GC system and determine the total number of GCs directly through observation. We find that rather than being an especially high-SN spiral, NGC 7814 has <~200 GCs and SN~1, making it comparable to the two most well-studied spiral galaxies, the Milky Way and M31. We explore the implications of these results for models of the formation of galaxies and their GC systems. The initial results from our survey suggest that the GC systems of typical elliptical galaxies can be accounted for by the merger of two or more spirals, but that for highly luminous elliptical galaxies, additional physical processes may be needed.

  10. Creating New Child Care Slots in Mini Child Care Centers: Big Bang for the Buck in New Jersey.

    Science.gov (United States)

    Frankel, Arthur J.; And Others

    1992-01-01

    Small grants of $7,500 with technical assistance were offered to the child care community of New Jersey to either start or increase licensed capacity in mini-child care centers. Results of a subsequent analysis showed that 26 grantees created 481 new child care slots at an average cost of $561 per slot. (Author/SM)

  11. 26 CFR 7.6041-1 - Return of information as to payments of winnings from bingo, keno, and slot machines.

    Science.gov (United States)

    2010-04-01

    ... winnings from bingo, keno, and slot machines. 7.6041-1 Section 7.6041-1 Internal Revenue INTERNAL REVENUE..., keno, and slot machines. (a) In general. On or after May 1, 1977, every person engaged in a trade or... machine play or of $1,500 or more from a keno game shall make an information return with respect to such...

  12. 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.

  13. 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.

  14. Effect of slot height variation on the aerodynamic performance of a circulation control airfoil: A CFD analysis

    Science.gov (United States)

    Capobianco, Vincent J.

    Computational fluid dynamic (CFD) simulations were conducted on a known low aspect ratio wing design as well as four variant designs incorporating Coanda effect circulation control (CC) for lift generation. The U.S. Navy's Kestrel code was employed to explore the relation of slot height and lip thickness to maximize lift augmentation. Reynolds Averaged Navier-Stokes calculations were performed at a Reynolds number of 2.1 million over wing configurations with a 1 ft span and chord with top slot flow blowing coefficients of 0, 0.005, 0.05, 0.1, and 0.15 over the angles of attack of 0°, 4°, 8°, 14°, and 18°. The computational results were compared to experimental measurements of slot unblown and blown configurations. General findings include higher lift augmentation ratios of modified designs with similar lip thickness and larger slot gap. Greater lift coefficients were found with larger lip thicknesses and smaller slot heights.

  15. Dynamic study of the larynx with spiral CT

    International Nuclear Information System (INIS)

    Park, Jong Yeon; Choi, Chang Ho; Yoon, Chi Soon; Kim, Yoon Gyoo; Nam, Sang Hwa; Kim, Kun Il; Kim, Byung Soo; Wang, Soo Guen

    1994-01-01

    It is essential to know the functional and morphologic changes of the larynx in the evaluation of laryngeal lesions. Conventional CT which has relatively long examination time is not suitable for this aim. The purposes of this study are to evaluate the capability of spiral CT in the dynamic study of the larynx and to know whether this new technique can replace conventional laryngography or not. Five healthy volunteers and 20 patients with laryngeal lesions underwent spiral dynamic CT scans with 3-dimensional reconstruction of the mucosal surface. A series of spiral CT scans were done while the volunteers performed various laryngeal positions to obtain the functional and morphologic information. The maneuvers used were: quite breathing, 'E' phonation, Valsalva maneuver, modified Valsalva maneuver, and a new method of our own, 'modified breath holding' technique. The patients were scanned when in quite breathing. Additional scans were obtained by using the 'modified breath holding' technique. The dynamic study with spiral CT could provide high resolutional images which nicely depicted the mobility of vocal cords and the mucosal changes of the laryngeal cavity in both healthy volunteer and patient groups. In patient group, the new 'modified breath holding' technique was easier and more reproducible than other maneuvers. Spiral CT allows a dynamic study of the larynx and can be a new alternative of laryngography

  16. On wave dark matter in spiral and barred galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Medina, Luis A.; Matos, Tonatiuh [Departamento de Física, Centro de Investigación y de Estudios Avanzados del IPN, A.P. 14-740, 07000 México D.F., México. (Mexico); Bray, Hubert L., E-mail: lmedina@fis.cinvestav.mx, E-mail: bray@math.duke.edu, E-mail: tmatos@fis.cinvestav.mx [Mathematics Department, Duke University, Box 90320, Durham, NC 27708 (United States)

    2015-12-01

    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.

  17. 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

  18. 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.

  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. Do cows prefer a barn compartment with a grooved or slotted floor

    NARCIS (Netherlands)

    Stefanowska, J.; Swierstra, D.; Berg, van den J.V.; Metz, J.H.M.

    2002-01-01

    Cow preferences for one of two compartments with different floors were tested in a barn with two symmetrical, connected compartments, each intended for 16 cows. Compartments were identical except for the floor. One floor was grooved longitudinally to the feeding barrier and the other was slotted

  1. Measurements on Buoyant Jet Flows from a Ceiling-Mounted Slot Diffuser

    DEFF Research Database (Denmark)

    Nielsen, Peter V.; Möller, Åke T. A.

    Ceiling-mounted slot diffusers in ventilated rooms will often generate a flow of the wall jet type. The jet follows the ceiling, entrains air from the occupied zone and generates a recirculating flow in the whole room. This paper will deal with the flow in the ceiling region. The wall jet flow...

  2. PIV and LIF study of slot continuous jet at low Reynolds number

    Czech Academy of Sciences Publication Activity Database

    Broučková, Zuzana; Hsu, S.S.; Wang, A. B.; Trávníček, Zdeněk

    2016-01-01

    Roč. 114, March (2016), č. článku 02007. ISSN 2101-6275. [International Conference on Experimental Fluid Mechanics /10./. Praha, 17.11.2015-20.11.2015] R&D Projects: GA ČR GA14-08888S Institutional support: RVO:61388998 Keywords : continuous jet * slot jet * particle image velocimetry Subject RIV: JU - Aeronautics, Aerodynamics, Aircrafts

  3. Perancangan Dan Pembuatan Antena Mikrostrip Rugby Ball Dengan Slot Lingkaran Pada Frekuensi Ultra Wideband (UWB)

    OpenAIRE

    Ir. Erfan Achmad Dahlan, MT., Silvi Aisiyah Dita Permata., Rudy Yuwono, ST., M.Sc

    2014-01-01

    Penelitian ini membahas tentang perancanganantena mikrostrip rugby ball dengan slot lingkaransehingga dapat bekerja pada frekuensi ultra wideband(UWB). Konsep UWB yang ditemukan dalamperancangan antena, ditujukan agar satu antena denganbandwidth yang lebar dapat diaplikasikan pada banyaksistem komunikasi dengan alokasi frekuensi yang berbedatiap aplikasinya. Antena mikrostrip ini dirancang denganmenggunakan insed feed line sebagai metodepencatuannya. Dimensi antena mikrostrip diperolehmelalui...

  4. Printed UWB Antenna with Coupled Slotted Element for Notch-Frequency Function

    Directory of Open Access Journals (Sweden)

    X. L. Bao

    2008-01-01

    Full Text Available A novel printed monopole antenna employing a slotted-plate, which is electromagnetically coupled to the microstrip-fed planar element, is proposed to provide notch-frequency function. This technique enables stopband characteristics with improved control, compared to placing the slot in the microstrip-fed element. A detailed investigation of the rejectband properties has been made for the UWB antenna. Measured data for the optimized case show the 10 dB return loss bandwidth to be 9.8 GHz (from 2.80 GHz to 12.60 GHz with a notchband frequency from 5.15 GHz to 5.825 GHz. Propagation measurements indicate that the electromagnetically coupled slot provides a greater reduction in stopband gain for the three principal planes, compared to placing the slot in the fed element. This is desirable to mitigate interference from WLAN systems. A full parametric study of the antenna is presented.

  5. A Pseudo-Bayesian Approach to Sign-Compute-Resolve Slotted ALOHA

    DEFF Research Database (Denmark)

    Goseling, Jasper; Stefanovic, Cedomir; Popovski, Petar

    2015-01-01

    Access reservation based on slotted ALOHA is commonly used in wireless cellular access. In this paper we investigate its enhancement based on the use of physical-layer network coding and signature coding, whose main feature is enabling simultaneous resolution of up to K users contending for access...

  6. A Universal Vacant Parking Slot Recognition System Using Sensors Mounted on Off-the-Shelf Vehicles

    Directory of Open Access Journals (Sweden)

    Jae Kyu Suhr

    2018-04-01

    Full Text Available An automatic parking system is an essential part of autonomous driving, and it starts by recognizing vacant parking spaces. This paper proposes a method that can recognize various types of parking slot markings in a variety of lighting conditions including daytime, nighttime, and underground. The proposed method can readily be commercialized since it uses only those sensors already mounted on off-the-shelf vehicles: an around-view monitor (AVM system, ultrasonic sensors, and in-vehicle motion sensors. This method first detects separating lines by extracting parallel line pairs from AVM images. Parking slot candidates are generated by pairing separating lines based on the geometric constraints of the parking slot. These candidates are confirmed by recognizing their entrance positions using line and corner features and classifying their occupancies using ultrasonic sensors. For more reliable recognition, this method uses the separating lines and parking slots not only found in the current image but also found in previous images by tracking their positions using the in-vehicle motion-sensor-based vehicle odometry. The proposed method was quantitatively evaluated using a dataset obtained during the day, night, and underground, and it outperformed previous methods by showing a 95.24% recall and a 97.64% precision.

  7. Fleet Planning Decision-Making: Two-Stage Optimization with Slot Purchase

    Directory of Open Access Journals (Sweden)

    Lay Eng Teoh

    2016-01-01

    Full Text Available Essentially, strategic fleet planning is vital for airlines to yield a higher profit margin while providing a desired service frequency to meet stochastic demand. In contrast to most studies that did not consider slot purchase which would affect the service frequency determination of airlines, this paper proposes a novel approach to solve the fleet planning problem subject to various operational constraints. A two-stage fleet planning model is formulated in which the first stage selects the individual operating route that requires slot purchase for network expansions while the second stage, in the form of probabilistic dynamic programming model, determines the quantity and type of aircraft (with the corresponding service frequency to meet the demand profitably. By analyzing an illustrative case study (with 38 international routes, the results show that the incorporation of slot purchase in fleet planning is beneficial to airlines in achieving economic and social sustainability. The developed model is practically viable for airlines not only to provide a better service quality (via a higher service frequency to meet more demand but also to obtain a higher revenue and profit margin, by making an optimal slot purchase and fleet planning decision throughout the long-term planning horizon.

  8. Scattering of Electromagnetic Radiation by Apertures: II. Oblique Incidence on the Slotted Plane for Parallel Polarization,

    Science.gov (United States)

    The report is the second in a series of investigations into the diffraction of electromagnetic radiation by apertures in conducting screens. Herein...is presented a technique for obtaining the fields everywhere for plane electromagnetic radiation incident obliquely on a slotted conducting plane. The

  9. Slot Machines: Pursuing Responsible Gaming Practices for Virtual Reels and Near Misses

    Science.gov (United States)

    Harrigan, Kevin A.

    2009-01-01

    Since 1983, slot machines in North America have used a computer and virtual reels to determine the odds. Since at least 1988, a technique called clustering has been used to create a high number of near misses, failures that are close to wins. The result is that what the player sees does not represent the underlying probabilities and randomness,…

  10. Experimental Hydraulic Optimization of the Wave Energy Converter Seawave Slot-Cone Generator

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter

    This report presents the results of a experimental hydraulic optimization of the wave energy convert (WEC) Seawave Slot-Cone Generator (SSG). SSG is a WEC utilizing wave overtopping in multiple reservoirs. In the present SSG setup three reservoirs has been used. Model tests have been performed...

  11. Wave Loadings on Seawave Slot-Cone Generator (SSG) at Kvitsøy Island

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Frigaard, Peter; Kofoed, Jens Peter

    This report presents results from a new research study performed to derive information on wave loadings acting on Wave Energy Convert (WEC) Seawave Slot-Cone Generator (SSG) exposed to extreme wave conditions. The SSG concept is based on the principle of overtopping and stores the wave energy...

  12. Model Testing of the Wave Energy Converter Seawave Slot-Cone Generator

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter

    This report presents the results of a preliminary experimental study of the wave energy convert (WEC) Seawave Slot-Cone Generator (SSG). SSG is a WEC utilizing wave overtopping in multiple reservoirs. In the present SSG setup three reservoirs has been used. Model tests have been performed using...

  13. The Effect of Slot-Code Optimization in Warehouse Order Picking

    Directory of Open Access Journals (Sweden)

    Andrea Fumi

    2013-07-01

    most appropriate material handling resource configuration. Building on previous work on the effect of slot-code optimization on travel times in single/dual command cycles, the authors broaden the scope to include the most general picking case, thus widening the range of applicability and realising former suggestions for future research.

  14. Problem-Matched Basis Functions for Microstrip Coupled Slot Antennas based on Transmission Line Greens Functions

    NARCIS (Netherlands)

    Bruni, S.; Llombart Juan, N.; Neto, A.; Gerini, G.; Maci, S.

    2004-01-01

    A general algorithm for the analysis of microstrip coupled leaky wave slot antennas was discussed. The method was based on the construction of physically appealing entire domain Methods of Moments (MoM) basis function that allowed a consistent reduction of the number of unknowns and of total

  15. Pulsed electromagnetic field radiation from a narrow slot antenna with a dielectric layer

    NARCIS (Netherlands)

    Štumpf, M.; De Hoop, A.T.; Lager, I.E.

    2010-01-01

    Analytic time domain expressions are derived for the pulsed electromagnetic field radiated by a narrow slot antenna with a dielectric layer in a two?dimensional model configuration. In any finite time window of observation, exact pulse shapes for the propagated, reflected, and refracted wave

  16. Large Ka-Band Slot Array for Digital Beam-Forming Applications

    Science.gov (United States)

    Rengarajan, Sembiam; Zawadzki, Mark S.; Hodges, Richard E.

    2011-01-01

    This work describes the development of a large Ka Band Slot Array for the Glacier and Land Ice Surface Topography Interferometer (GLISTIN), a proposed spaceborne interferometric synthetic aperture radar for topographic mapping of ice sheets and glaciers. GLISTIN will collect ice topography measurement data over a wide swath with sub-seasonal repeat intervals using a Ka-band digitally beamformed antenna. For technology demonstration purpose a receive array of size 1x1 m, consisting of 160x160 radiating elements, was developed. The array is divided into 16 sticks, each stick consisting of 160x10 radiating elements, whose outputs are combined to produce 16 digital beams. A transmit array stick was also developed. The antenna arrays were designed using Elliott's design equations with the use of an infinite-array mutual-coupling model. A Floquet wave model was used to account for external coupling between radiating slots. Because of the use of uniform amplitude and phase distribution, the infinite array model yielded identical values for all radiating elements but for alternating offsets, and identical coupling elements but for alternating positive and negative tilts. Waveguide-fed slot arrays are finding many applications in radar, remote sensing, and communications applications because of their desirable properties such as low mass, low volume, and ease of design, manufacture, and deployability. Although waveguide-fed slot arrays have been designed, built, and tested in the past, this work represents several advances to the state of the art. The use of the infinite array model for the radiating slots yielded a simple design process for radiating and coupling slots. Method of moments solution to the integral equations for alternating offset radiating slots in an infinite array environment was developed and validated using the commercial finite element code HFSS. For the analysis purpose, a method of moments code was developed for an infinite array of subarrays. Overall

  17. 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)

  18. Spiral waves in the Belousov-Zhabotinskii reaction

    Science.gov (United States)

    Keener, James P.; Tyson, John J.

    1986-09-01

    The beautiful spiral waves of oxidation in the Belousov-Zhabotinskii reaction are the source of many interesting and important questions about periods structures in excitable media. It has long been known that these spirals are similar to involutes of circles, at least some distance from the center, but until now, no way has been known to determine the correct wavelength and frequency. In this paper, we show that the parameters of a spiral wave can be viwed s eigenvalues of a problem with unique solution. The critical ingredients of the theory are the effects of curvature on the propagation of wavefronts in two-dimensional media, and the dispersion of plane waves Our analytical results are shown to be in good agreement with experimental data for the Belousov-Zhabotinskii reagent.

  19. 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.

  20. 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

  1. 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

  2. Study on a new water purification equipment with spiral lamellas

    Science.gov (United States)

    Feng, X. R.

    2017-08-01

    A new water purification equipment was introduced, especially the section of spiral lamellas. Utilization of spiral lamellas made the sedimentation space reach to 100%, not only improving sedimentation efficiency and reducing the cover space, but also saving investment. Production test results showed that the new water purification equipment with spiral lamellas had characteristics of excellent treatment efficiency and high shock resistant capacity. As the treatment water volume was 240 m3/d, when the turbidity, CODMn and UV254 were 203 NTU, 1.90 mg/L and 0.030 cm-1 in raw water, they were 0.32 NTU, 0.72mg/L and 0.011 cm-1 respectively in effluent water, which could fully meet the drinking water hygiene requirement.

  3. 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...

  4. 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

  5. Spiral CT for cervical lymph node enlargement. Early clinical results

    International Nuclear Information System (INIS)

    Steinkamp, H.J.; Keske, U.; Schedel, J.; Hosten, N.; Felix, R.

    1994-01-01

    Spiral CT was performed before treatment in 35 patients with suspected cervical lymph node enlargement. By coronary and sagittal reconstruction it is possible to utilise the M/Q quotient which has become accepted as the result of sonographic and MRI examinations. It is now possible to obtain high diagnostic accuracy (97%) for distinguishing between reactive change from metastatic infiltration of lymph nodes (>8 mm) by using CT. Using spiral CT with 5 mm table movement, three patients diagnosed as stage N1 by axial CT were shown to be N2b. This represents a highly sensitive and highly specific method of lymph node diagnosis. Further diagnostic improvement derives from the ability to relate the lymph nodes to surrounding tissues. Spiral CT is also suitable for defining other space occupying lesions, e.g., the exact extent of retropharyngeal abscesses, abnormalities of the salivary glands or laryngocoeles. (orig.)

  6. Elevated CPW-Fed Slotted Microstrip Antenna for Ultra-Wideband Application

    Directory of Open Access Journals (Sweden)

    Chandan Kumar Ghosh

    2012-01-01

    Full Text Available Elevated-coplanar-waveguide- (ECPW- fed microstrip antenna with inverted “G” slots in the back conductor is presented. It is modeled and analyzed for the application of multiple frequency bands. The changes in radiation and the transmission characteristics are investigated by the introduction of the slots in two different positions at the ground plane (back conductor. The proposed antenna without slots exhibits a stop band from 2.55 GHz to 4.25 GHz while introducing two slots on the back conductor, two adjacent poles appear at central frequencies of 3.0 GHz and 3.9 GHz, respectively, and the antenna shows the ultra-wideband (UWB characteristics. The first pole appears at the central frequency of 3.0 GHz and covers the band width of 950 MHz, and the second pole exists at a central frequency of 3.90 GHz covering a bandwidth of 750 MHz. Experimental result shows that impedance bandwidth of 129% (S11<-10 dB is well achieved when the antenna is excited with both slots. Compared to most of the previously reported ECPW structures, the impedance bandwidth of this antenna is increased and also the size of the antenna becomes smaller and more suitable for many wireless applications like PCS (1850–1990 MHz, WLAN (2.4–2.484 GHz, WiMAX (2.5–2.69 GHz and 5.15–5.85 GHz, and also X-band communication.

  7. Evaluation of surface roughness of the bracket slot floor—a 3D perspective study

    Directory of Open Access Journals (Sweden)

    Chetankumar O. Agarwal

    2016-01-01

    Full Text Available Abstract Background An important constituent of an orthodontic appliance is orthodontic brackets. It is either the bracket or the archwire that slides through the bracket slot, during sliding mechanics. Overcoming the friction between the two surfaces demands an important consideration in an appliance design. The present study investigated the surface roughness of four different commercially available stainless steel brackets. Methods All tests were carried out to analyse quantitatively the morphological surface of the bracket slot floor with the help of scanning electron microscope (SEM machine and to qualitatively analyse the average surface roughness (Sa of the bracket slot floor with the help of a three-dimensional (3D non-contact optical surface profilometer machine. Results The SEM microphotographs were evaluated with the help of visual analogue scale, the surface roughness for group A = 0—very rough surface, group C = 1—rough surface, group B = 2—smooth surface, and group D = 3—very smooth surface. Surface roughness evaluation with the 3D non-contact optical surface profilometer machine was highest for group A, followed by group C, group B and group D. Groups B and D provided smooth surface roughness; however, group D had the very smooth surface with values 0.74 and 0.75 for mesial and distal slots, respectively. Conclusions Evaluation of surface roughness of the bracket slot floor with both SEM and profilometer machine led to the conclusion that the average surface roughness was highest for group A, followed by group C, group B and group D.

  8. Diffusive Transport of Several Hundred keV Electrons in the Earth's Slot Region

    Science.gov (United States)

    Ma, Q.; Li, W.; Thorne, R. M.; Bortnik, J.; Reeves, G. D.; Spence, H. E.; Turner, D. L.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Baker, D. N.

    2017-10-01

    We investigate the gradual diffusion of energetic electrons from the inner edge of the outer radiation belt into the slot region. The Van Allen Probes observed slow inward diffusion and decay of 200-600 keV electrons following the intense geomagnetic storm that occurred on 17 March 2013. During the 10 day nondisturbed period following the storm, the peak of electron fluxes gradually moved from L 2.7 to L 2.4, and the flux levels decreased by a factor of 2-4 depending on the electron energy. We simulated the radial intrusion and decay of electrons using a three-dimensional diffusion code, which reproduced the energy-dependent transport of electrons from 100 keV to 1 MeV in the slot region. At energies of 100-200 keV, the electrons experience fast transport across the slot region due to the dominance of radial diffusion; at energies of 200-600 keV, the electrons gradually diffuse and decay in the slot region due to the comparable rate of radial diffusion and pitch angle scattering by plasmaspheric hiss; at energies of E > 700 keV, the electrons stopped diffusing near the inner edge of outer radiation belt due to the dominant pitch angle scattering loss. In addition to plasmaspheric hiss, magnetosonic waves and VLF transmitters can cause the loss of high pitch angle electrons, relaxing the sharp "top-hat" shaped pitch angle distributions created by plasmaspheric hiss. Our simulation indicates the importance of balance between radial diffusion and loss through pitch angle scattering in forming the diffusive intrusion of energetic electrons across the slot region.

  9. Diffusive transport of several hundred keV electrons in the Earth's slot region

    Science.gov (United States)

    Ma, Q.; Li, W.; Thorne, R. M.; Bortnik, J.

    2017-12-01

    We investigate the gradual diffusion of energetic electrons from the inner edge of the outer radiation belt into the slot region. The Van Allen Probes observed slow inward diffusion and decay of 200-600 keV electrons following the intense geomagnetic storm that occurred on 17 March 2013. During the 10-day non-disturbed period following the storm, the peak of electron fluxes gradually moved from L 2.7 to L 2.4, and the flux levels decreased by a factor of 2-4 depending on the electron energy. We simulated the radial intrusion and decay of electrons using a 3-dimentional diffusion code, which reproduced the energy-dependent transport of electrons from 100 keV to 1 MeV in the slot region. At energies of 100-200 keV, the electrons experience fast transport across the slot region due to the dominance of radial diffusion; at energies of 200-600 keV, the electrons gradually diffuse and decay in the slot region due to the comparable radial diffusion rate and pitch angle scattering rate by plasmaspheric hiss; at energies of E > 700 keV, the electrons stopped diffusing near the inner edge of outer radiation belt due to the dominant pitch angle scattering loss. In addition to plasmaspheric hiss, magnetosonic waves and VLF waves can cause the loss of high pitch angle electrons, relaxing the sharp `top-hat' shaped pitch angle distributions created by plasmaspheric hiss. Our simulation indicates the importance of radial diffusion and pitch angle scattering in forming the diffusive intrusion of energetic electrons across the slot region.

  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. 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

  12. 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

  13. Spiral CT angiography of the abdominal aorta and its branches

    Energy Technology Data Exchange (ETDEWEB)

    Costello, P. [Dept. of Radiology, Deaconess Hospital and Harvard Medical School, Boston, MA (United States); Gaa, J. [Dept. of Radiology, Deaconess Hospital and Harvard Medical School, Boston, MA (United States)

    1993-08-01

    Spiral CT angiography (CTA) was performed on 19 patients for the pre-operative assessment of abdominal aortic aneurysms and in 3 post-operative renal artery bypass patients. Spiral CTA performed during intravenous contrast infusion provided a volume of data that was reconstructed at thin increments. Images were edited and reformatted either as surface rendered three-dimensional or maximum intensity projection (MIP) displays. Final images were viewed in a cine-loop presentation of quality comparable to conventional angiograms. The entire aorta can be examined from the coeliac axis to mid-pelvis with only 107 ml of 60% contrast. (orig.)

  14. 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

  15. Necessity for High Accuracy Rotation Curves in Spiral Galaxies

    OpenAIRE

    Blais-Ouellette, Sebastien; Carignan, Claude; Amram, Philippe

    1998-01-01

    In the last 20 years, rotation curves derived from H I kinematics obtained on radio synthesis instruments were used to probe the dark matter distribution in spiral and dwarf irregular galaxies. It is shown, with the aid of the Sd galaxy NGC 5585, that high resolution 2--D H II kinematics is necessary to determine accurately the mass distribution of spirals. New CFHT Fabry--Perot Hff observations are combined with low resolution Westerbork H I data to study its mass distribution. Using the com...

  16. 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 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...

  17. 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

  18. Detailed Study of Closed Stator Slots for a Direct-Driven Synchronous Permanent Magnet Linear Wave Energy Converter

    Directory of Open Access Journals (Sweden)

    Erik Lejerskog

    2014-01-01

    Full Text Available The aim of this paper is to analyze how a permanent magnet linear generator for wave power behaves when the stator slots are closed. The usual design of stator geometry is to use open slots to maintain a low magnetic leakage flux between the stator teeth. By doing this, harmonics are induced in the magnetic flux density in the air-gap due to slotting. The closed slots are designed to cause saturation, to keep the permeability low. This reduces the slot harmonics in the magnetic flux density, but will also increase the flux leakage between the stator teeth. An analytical model has been created to study the flux through the closed slots and the result compared with finite element simulations. The outcome shows a reduction of the cogging force and a reduction of the harmonics of the magnetic flux density in the air-gap. It also shows a small increase of the total magnetic flux entering the stator and an increased magnetic flux leakage through the closed slots.

  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. 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.

  1. Two-Dimensional Air-Flow Tests of the Effect of ITA Flowliner Slot Modification by Grinding/Polishing on Edge Tone Generation Potential

    Science.gov (United States)

    Sutliff, Daniel L. (Technical Monitor); Walker, Bruce E.

    2004-01-01

    Hersh Walker Acoustics (HWA) has performed a series of wind tunnel tests to support crack-repair studies for ITA flowliner vent slots. The overall goal of these tests is to determine if slot shape details have a significant influence on the propensity of the flowliner to produce aero-acoustic oscillations that could increase unsteady stresses on the flowliner walls. The test series, conducted using a full-scale two-dimensional model of a six-slot segment of the 38 slot liner, was intended to investigate the effects of altering slot shape by grinding away cracked portions.

  2. 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

  3. EM-wave absorption properties of hollow spiral iron particles

    International Nuclear Information System (INIS)

    Zhang, Wenqiang; Zhang, Deyuan

    2015-01-01

    Hollow iron spiral particles were fabricated successfully by thermal decomposition method, and they were heat-treated at different temperatures in N 2 atmosphere. The electromagnetic wave absorption properties of hollow iron spiral particles were investigated ranging between 1 GHz and 18 GHz. The results indicated that the phase structures of the particles changed from amorphous to nanocrystal with the treating temperature rising, also causing the significant change in electromagnetic parameters and the reflection loss. The reflection loss could reach −33 dB at 16.2 GHz, indicating that the hollow iron spiral particles had the potential to be used in prepare the a high property EM-wave absorber. - Highlights: • Hollow iron spiral particles were fabricated by thermal decomposition method. • The particles changed from amorphous to nanocrystals with heat-treatment. • Particles’ EM-parameters have a great change after high temperature heat-treatment. • RL results show the particles have potential to be high property EM-wave absorber

  4. 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

  5. Teaching about Energy Through a Spiral Curriculum: Guiding Principles.

    Science.gov (United States)

    Trumper, Ricardo

    1996-01-01

    Conventional science instruction often fails to address or change students' misconceptions about physical phenomena. Students stubbornly cling to anthropocentric, causal, and product conceptions about energy. This article explores scientific and pedagogical arguments favoring development of a spiral curriculum for teaching energy in (Israeli)…

  6. 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...

  7. Multivessel myocardial bridging in a patient with spiral hypertrophic cardiomyopathy

    OpenAIRE

    Fritz, Timothy; Abdallah, Wissam; McNamara, Richard

    2016-01-01

    Myocardial bridging is commonly observed in hypertrophic cardiomyopathy, usually confined to the left anterior descending (LAD), and correlates to the hypertrophic septum. We present a patient with unique spiral hypertrophic cardiomyopathy (HCM) and compression of all three coronary arteries corresponding to this hypertrophy pattern.

  8. 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...

  9. Abundance analysis of giant H II regions in nearby spirals

    OpenAIRE

    Díaz, Angeles I.; Terlevich, E.; Pagel, B.E.J.; Vílchez, J.M; Edmunds, M.G.

    1990-01-01

    This is an electronic version of an article published in Revista Mexicana de Astronomía y Astrofísica. Díaz, Angeles I. et al. Abundance analysis of giant H II regions in nearby spirals. Revista Mexicana de Astronomía y Astrofísica 21 (1990): 223-227

  10. 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

    . However, in the master’s program, such a tight schedule is impractical since students are likely to seek specialization. From a pedagogical point of view, the spiral curriculum is advantageous to use in the initial semesters where the teaching can be conducted so that the students can build...

  11. 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 ...

  12. Learning in 3D Virtual Environments: Collaboration and Knowledge Spirals

    Science.gov (United States)

    Burton, Brian G.; Martin, Barbara N.

    2010-01-01

    The purpose of this case study was to determine if learning occurred within a 3D virtual learning environment by determining if elements of collaboration and Nonaka and Takeuchi's (1995) knowledge spiral were present. A key portion of this research was the creation of a Virtual Learning Environment. This 3D VLE utilized the Torque Game Engine…

  13. 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...

  14. 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.

  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 replacement...

  16. Multiferroic Magnetic Spirals Induced by Random Magnetic Exchanges

    Science.gov (United States)

    Scaramucci, Andrea; Shinaoka, Hiroshi; Mostovoy, Maxim V.; Müller, Markus; Mudry, Christopher; Troyer, Matthias; Spaldin, Nicola A.

    2018-01-01

    Multiferroism can originate from the breaking of inversion symmetry caused by magnetic-spiral order. The usual mechanism for stabilizing a magnetic spiral is competition between magnetic exchange interactions differing by their range and sign, such as nearest-neighbor and next-nearest-neighbor interactions. In insulating compounds, it is unusual for these interactions to be both comparable in magnitude and of a strength that can induce magnetic ordering at room temperature. Therefore, the onset temperatures for multiferroism through this mechanism are typically low. By considering a realistic model for multiferroic YBaCuFeO5 , we propose an alternative mechanism for magnetic-spiral order, and hence for multiferroism, that occurs at much higher temperatures. We show, using Monte Carlo simulations and electronic structure calculations based on density functional theory, that the Heisenberg model on a geometrically nonfrustrated lattice with only nearest-neighbor interactions can have a spiral phase up to high temperature when frustrating bonds are introduced randomly along a single crystallographic direction as caused, e.g., by a particular type of chemical disorder. This long-range correlated pattern of frustration avoids ferroelectrically inactive spin-glass order. Finally, we provide an intuitive explanation for this mechanism and discuss its generalization to other materials.

  17. Embedded spiral patterns in the massive galaxy cluster Abell 1835

    Science.gov (United States)

    Ueda, S.; Kitayama, T.; Dotani, T.

    2017-10-01

    We report on the properties of the intracluster medium (ICM) in the central region of the massive galaxy cluster, Abell 1835, obtained with the data from the Chandra X-ray Observatory. We find distinctive spiral patterns in the cool core in the residual image of the X-ray surface brightness after its nominal profile is subtracted. The spiral patterns consist of two arms. One of them appears as positive, and the other appears as negative excesses in the residual image. Their sizes are ˜ 70 kpc and their morphologies are consistent with each other. We find that the spiral patterns extend from the cool core out to the hotter surrounding ICM. We analyze the X-ray spectra extracted from both regions. We obtain that the ICM properties are similar to those expected by gas sloshing. We also find that the ICM in the two regions of spiral patterns is near or is in pressure equilibrium. Abell 1835 may now be experiencing gas sloshing induced by an off-axis minor merger. These results have been already published (Ueda, Kitayama, & Dotani 2017, ApJ, 837, 34).

  18. 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

  19. 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.)

  20. 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

  1. 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…

  2. Ekman Spiral in Horizontally Inhomogeneous Ocean with Varying Eddy Viscosity

    Science.gov (United States)

    2015-01-01

    thermocline (in temperature) and pycnocline (in density) (e.g., Kraus and Turner 1967; Garwood 1977; Chu and Garwood 1991; Steger et al. 1998; Chu et...spiral as a good statistical fit to low-frequency currents in a coastal strait. Science, 233, 470-472. Steger , J., Collins, C.A., and Chu, P.C. (1998

  3. THE MASS-DISTRIBUTION OF THE DWARF SPIRAL NGC-1560

    NARCIS (Netherlands)

    BROEILS, AH

    H I synthesis observations with the WSRT and optical surface photometry of the dwarf spiral galaxy NGC 1560 are presented. This galaxy has an absolute luminosity of M(B) = -15.87. The observations show that the galaxy is gas rich, with an M(HI)/L(B) of 2.4. We obtained a very detailed rotation curve

  4. Evaluation of spiral CT in the diagnosis of ureteral diseases

    International Nuclear Information System (INIS)

    Li Jiansheng; Li Kangyin; Chen Huyi; Qiang Haixia; Shen Guoqiang; Li Jing

    2001-01-01

    Objective: To discuss the diagnostic value of spiral CT in ureteral diseases. Methods: Spiral CT urography (SCTU) was performed in 27 cases with ureteral diseases, including 9 cases of ureteral calculus, 5 carcinomas, 9 stenosis, 1 malformation, 1 inflammation and 2 fistula. Of the 27 cases,15 also underwent non-enhanced spiral CT scan and 10 received intravenous urography(IVU). Results: (1) Eight cases of radiolucent ureteral calculus were clearly showed by non-enhanced spiral CT. (2) On SCTU, the location and diameter of 9 ureteral calculus (8 radiolucent, 1 radiopaque) and enlargement of renal pelvis and ureter were displayed. Irregular ureteral wall, local rarefaction or obstruction of contrast medium in ureter were detected in 5 case of tumor. Ureteral lumen was narrowed gradually in 7 cases of simple ureteral stenosis without thickening of the wall. Two cases with ectopic vessel compression were clarified at the boundary of ureter and pelvis. 1 malformation with double renal pelvis and ureter was demonstrated. The location and direction of ureteral fistula were notified. Conclusion: SCTU is superior to IVU and conventional CT in improving diagnostic accuracy of ureteral disease

  5. Intervention of malignant biliary obstruction with Hanaro spiral stent

    International Nuclear Information System (INIS)

    Shin, Sung Wook; Choo, Sung Wook; Pyeun, Yong Seon and others

    1999-01-01

    To evaluate the long-term patency of the Hanaro spiral stent (Solco Intermed, Seoul, Korea) when used as a palliative in patients with inoperable malignant biliary obstruction. Between April 1996 and July 1998, 39 patients with malignant biliary obstruction underwent percutaneous placement of 48 Hanaro spiral stents. The causes of obstruction were bile duct carcinoma (n=18), pancreatic carcinoma (n=8), metastatic lymphadenopathy (n=5), gallbladder carcinoma (n=5), hepatocellular carcinoma (n=1) and other tumors (n=2). Using the kaplan-Meier method, patient survival and stet patency rates were estimated with regard to level of obstruction. As regards stent insertion, there was no technical failure. Overall 25- and 50-week survival rates for the entire patient group were 50 % and 11 %, respectively, while overall stent patency rates at 25 and 50 weeks were 42 % and 11 %, respectively. Twenty-five-week stent patency rates in patients with common bile duct (CBD) and hilar obstruction were 51 % and 18 %, respectively. The stent patency rates in the CBD obstruction group was significantly higher than that in the hilar obstruction group (p<0.05). In patients with CBD obstruction, the clinical efficacy of Hanaro spiral stent was superior to that in patients with hilar obstruction. However, Hanaro spiral stents showed a lower patency rate with regard to patient survival, and further investigation is required

  6. 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 ...

  7. 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

  8. 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)

  9. 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

  10. 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

  11. 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.

  12. Experimental analysis of the game in pathological gamblers: effect of the immediacy of the reward in slot machines.

    Science.gov (United States)

    Chóliz, Mariano

    2010-06-01

    Slot machines are the most "addictive" games because (a) the disorder (pathological gambling) appears more rapidly in these games than with any other; (b) most patients who seek professional help are mainly addicted to electronic gambling, and (c) even though it is not the more frequent game, most of all the money spent on legal games of chance (at least in Spain) goes to slot machines. Structural characteristics of slot machines induce to gamble because electronic games show the main parameters of operant conditioning, mainly the immediacy of the reinforcement. Ten pathological gamblers played slot machine in two conditions: immediate and delayed reinforcement. The results corroborate the importance of the immediacy of the reinforcement in gambling, because when the result appears immediately (after 2 s), more games are played than when the result is delayed only 10 s. Critical issues in problem gambling prevention and public health are discussed.

  13. Effect of pole number and slot number on performance of dual rotor permanent magnet wind power generator using ferrite magnets

    Directory of Open Access Journals (Sweden)

    Peifeng Xu

    2017-05-01

    Full Text Available Dual rotor permanent magnet (DRPM wind power generator using ferrite magnets has the advantages of low cost, high efficiency, and high torque density. How to further improve the performance and reduce the cost of the machine by proper choice of pole number and slot number is an important problem to be solved when performing preliminarily design a DRPM wind generator. This paper presents a comprehensive performance comparison of a DRPM wind generator using ferrite magnets with different slot and pole number combinations. The main winding factors are calculated by means of the star of slots. Under the same machine volume and ferrite consumption, the flux linkage, back-electromotive force (EMF, cogging torque, output torque, torque pulsation, and losses are investigated and compared using finite element analysis (FEA. The results show that the slot and pole number combinations have an important impact on the generator properties.

  14. Electromagnetically induced transparency and ultraslow optical solitons in a coherent atomic gas filled in a slot waveguide.

    Science.gov (United States)

    Xu, Jin; Huang, Guoxiang

    2013-02-25

    We investigate the electromagnetically induced transparency (EIT) and nonlinear pulse propagation in a Λ-type three-level atomic gas filled in a slot waveguide, in which electric field is strongly confined inside the slot of the waveguide due to the discontinuity of dielectric constant. We find that EIT effect can be greatly enhanced due to the reduction of optical-field mode volume contributed by waveguide geometry. Comparing with the atomic gases in free space, the EIT transparency window in the slot waveguide system can be much wider and deeper, and the Kerr nonlinearity of probe laser field can be much stronger. We also prove that using slot waveguide ultraslow optical solitons can be produced efficiently with extremely low generation power.

  15. On the feasibility of constructing an imaging array of slot-antennas integrated with SIS mixers. [radio astronomy

    Science.gov (United States)

    Winkler, D.; Mcgrath, W. R.; Nilsson, B.; Claeson, T.; Johansson, J.; Kollberg, E.; Yngvesson, K. S.; Rudner, S.

    1986-01-01

    A prototype 700 GHz subharmonically pumped superconductor-insulator-superconductor (SIS) mixer integrated with a tapered slot antenna on a silicon substrate is described. Imaging using integrated SIS-mixer-antenna chips is discussed.

  16. Effect of Substrate Permittivity and Thickness on Performance of Single-Layer, Wideband, U-Slot Antennas on Microwave Substrates

    National Research Council Canada - National Science Library

    Natarajan, V; Chatterjee, D

    2004-01-01

    This paper presents effects of substrate permittivity and thickness on the performance characteristics like impedance bandwidth, radiation efficiency and gain of a single-layer, wideband, U-slot antenna...

  17. Error Floor Analysis of Coded Slotted ALOHA over Packet Erasure Channels

    DEFF Research Database (Denmark)

    Ivanov, Mikhail; Graell i Amat, Alexandre; Brannstrom, F.

    2014-01-01

    We present a framework for the analysis of the error floor of coded slotted ALOHA (CSA) for finite frame lengths over the packet erasure channel. The error floor is caused by stopping sets in the corresponding bipartite graph, whose enumeration is, in general, not a trivial problem. We therefore ...... identify the most dominant stopping sets for the distributions of practical interest. The derived analytical expressions allow us to accurately predict the error floor at low to moderate channel loads and characterize the unequal error protection inherent in CSA.......We present a framework for the analysis of the error floor of coded slotted ALOHA (CSA) for finite frame lengths over the packet erasure channel. The error floor is caused by stopping sets in the corresponding bipartite graph, whose enumeration is, in general, not a trivial problem. We therefore...

  18. Wind-Tunnel Investigation of an NACA 23012 Airfoil with Various Arrangements of Slotted Flaps

    Science.gov (United States)

    Wenzinger, Carl J; Harris , Thomas A

    1939-01-01

    An investigation was made in the 7 by 10-foot wind tunnel and in the variable-density wind tunnel of the NACA 23012 airfoil with various slotted-flap arrangements. The purpose of the investigation in the 7 by 10-foot wind tunnel was to determine the airfoil section aerodynamic characteristics as affected by flap shape, slot shape, and flap location. The flap position for maximum lift; polars for arrangements favorable for take-off and climb; and complete lift, drag, and pitching-moment characteristics for selected optimum arrangements were determined. The best arrangements were tested in the variable-density tunnel at an effective Reynolds number of 8,000,000. In addition, data from both wind tunnels are included for plain, split, external-airfoil, and Fowler flaps for purposes of comparison.

  19. High S/N Ratio Slotted Step Piezoresistive Microcantilever Designs for Biosensors

    Directory of Open Access Journals (Sweden)

    Mohd Zahid Ansari

    2013-03-01

    Full Text Available This study proposes new microcantilever designs in slotted step configuration to improve the S/N ratio of surface stress-based sensors used in physical, chemical, biochemical and biosensor applications. The cantilevers are made of silicon dioxide with a u-shaped silicon piezoresistor in p-doped. The cantilever step length and piezoresistor length is varied along with the operating voltage to characterise the surface stress sensitivity and thermal drifting sensitivity of the cantilevers when used as immunosensor. The numerical analysis is performed using ANSYS Multiphysics. Results show the surface stress sensitivity and the S/N ratio of the slotted step cantilevers is improved by more than 32% and 22%, respectively, over its monolithic counterparts.

  20. A U-Shaped Slot UWB Antenna with Flexible and Wide Tunable Dual Notch Band

    Directory of Open Access Journals (Sweden)

    Zhang Zhongmin

    2016-01-01

    Full Text Available A coplanar waveguide (CPW fed ultra-wideband (UWB antenna with flexible and wide tunable dual bandnotched characteristics is proposed in this paper. The dual band-notched function is achieved by using an U-shaped slot inserted into the ellipse radiation patch and by using an elliptic parasitic slit placed near the ground plane. The wide tunable band-notched characteristic is implemented by adjusting the length of U-shaped slot and by adjusting the length of ellipse parasitic slit. The design aims to achieve wide reconfigurable band-notched features on the UWB antenna. The simulated results indicate that the proposed antenna has a wide bandwidth (VSWR under 2 from 2.9GHz to 12.6GHz with fractional bandwidth of 125%, and has a wide tunable notch band center frequency from 4.5GHz to 12.4GHz.

  1. Quadrature Slotted Surface Coil Pair for Magnetic Resonance Imaging at 4 Tesla: Phantom Study

    Directory of Open Access Journals (Sweden)

    Solis S.E.

    2012-01-01

    Full Text Available A coil array was composed of two slotted surface coils forming a structure with two plates at 900, each one having 6 circular slots and is introduced in this paper. Numerical simulations of the magnetic field of this coil array were performed at 170 MHz using the finite element method to study its behaviour. This coil array was developed for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode and quadrature driven. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. In vitro images showed the feasibility of this coil array for standard pulses and high field magnetic resonance imaging.

  2. Design of CPW fed printed slot antenna with circular polarization for UWB application

    Science.gov (United States)

    Choudhary, N.; Tiwari, A.; Jangid, K. G.; Sharma, B. R.; Saini, J. S.; Kulhar, V. S.; Bhatnagar, D.

    2016-03-01

    This paper reports the design and performance of a CPW-fed circularized polarized elliptical slot antenna for UWB (ultra wide band) applications. The circular polarization is achieved by applying triangular stubs in the ground plane. The overall volume of this antenna is 40mm × 40 mm × 1.59 mm. The proposed antenna is simulated by applying CST Microwave Studio simulator. This elliptical patch slot antenna provides broad impedance bandwidth (3.1GHz to 10.6 GHz) with maximum gain 4.31dB at 4.45GHz. The simulated 3-dB axial ratio bandwidth is close to 2.51GHz (from 4.76GHz to 7.27GHz) which is 41.76% with respect to the central frequency 6.01GHz.

  3. Slot silicon-gallium nitride waveguide in MMI structures based 1x8 wavelength demultiplexer

    Science.gov (United States)

    Ben Zaken, Bar Baruch; Zanzury, Tal; Malka, Dror

    2017-06-01

    We propose a novel 8-channel wavelength multimode interference (MMI) demultiplexer in slot waveguide structures that operated at 1530 nm, 1535 nm, 1540 nm, 1545 nm, 1550 nm, 1555 nm, 1560 nm and 1565 nm wavelengths. Gallium nitride (GaN) surrounded by silicon (Si) was founded as suitable materials for the slot-waveguide structures. The proposed device was designed by seven 1x2 MMI couplers, fourteen S-band and one input taper. Numerical investigations were carried out on the geometrical parameters by using a full vectorial-beam propagation method (FVBPM). Simulation results show that the proposed device can transmit 8-channel that works in the whole C-band (1530- 1565 nm) with low crosstalk ((-19.97)-(-13.77) dB) and bandwidth (1.8-3.6 nm). Thus, the device can be very useful in optical networking systems that work on dense wavelength division multiplexing (DWDM) technology.

  4. Shape Measurement of Ellipsoidal Particles in a Cross-Slot Microchannel Utilizing Viscoelastic Particle Focusing.

    Science.gov (United States)

    Kim, Junghee; Kim, Jun Young; Kim, Younghun; Lee, Seong Jae; Kim, Ju Min

    2017-09-05

    Shape measurement of nonspherical microparticles by conventional methods such as optical microscopy is challenging owing to particle aggregation or uncertainty regarding the out-of-plane arrangement of particles. In this work, we propose a facile microfluidic method to align particles in-plane utilizing the extensional flow field generated in a cross-slot microchannel. Viscoelastic particle focusing is also harnessed to move particles toward the stagnation point of the cross-slot microchannel. We demonstrate that the shapes of ellipsoidal particles with various aspect ratios can be successfully measured using our novel microfluidic method. This method is expected to be useful in a wide range of applications such as shape measurement of nonspherical cells.

  5. A Novel Structure and Design Optimization of Compact Spline-Parameterized UWB Slot Antenna

    Directory of Open Access Journals (Sweden)

    Koziel Slawomir

    2016-12-01

    Full Text Available In this paper, a novel structure of a compact UWB slot antenna and its design optimization procedure has been presented. In order to achieve a sufficient number of degrees of freedom necessary to obtain a considerable size reduction rate, the slot is parameterized using spline curves. All antenna dimensions are simultaneously adjusted using numerical optimization procedures. The fundamental bottleneck here is a high cost of the electromagnetic (EM simulation model of the structure that includes (for reliability an SMA connector. Another problem is a large number of geometry parameters (nineteen. For the sake of computational efficiency, the optimization process is therefore performed using variable-fidelity EM simulations and surrogate-assisted algorithms. The optimization process is oriented towards explicit reduction of the antenna size and leads to a compact footprint of 199 mm2 as well as acceptable matching within the entire UWB band. The simulation results are validated using physical measurements of the fabricated antenna prototype.

  6. Stability analysis of slot-entry hybrid journal bearings operating with non-newtonian lubricant

    Directory of Open Access Journals (Sweden)

    H.C. Garg

    2015-09-01

    Full Text Available This paper presents theoretical investigations of rheological effects of lubricant on stability parameters of various configurations of slot-entry hybrid journal bearing system. FEM has been used to solve Reynolds equation governing flow of lubricant in bearing clearance space along with restrictor flow equation using suitable iterative technique. The non-Newtonian lubricant has been assumed to follow cubic shear stress law. The stability parameters in terms of stiffness coefficients, damping coefficients, threshold speed and whirl frequency of different configurations of slot-entry hybrid journal bearing have been computed and presented for wide range of external load while operating with Newtonian and Non-Newtonian lubricants. The computed results reveal that variation of viscosity due to non-Newtonian behavior of lubricant affects bearing stability quite significantly. The results are presented in graphical form and logical conclusions are drawn to identify best possible configuration from stability point of view.

  7. Performance evaluation of fractional-slot tubular permanent magnet machines with low space harmonics

    Directory of Open Access Journals (Sweden)

    Wang Jiabin

    2015-12-01

    Full Text Available This paper evaluates the perforamnce of fractional-slot per pole winding configurations for tubular permanent magnet (PM machines that can effectively eliminate the most undesirable space harmonics in a simple and cost-effective manner. The benefits of the proposed machine topology winding configurations are illustrated through comparison with 9-slot, 10-pole tubular PM machine developed for a free piston energy converter under the same specification and volumetric constraints. It has been shown that the proposed machine topology results in more than 7 times reduction in the eddy current loss in the mover magnets and supporting tube, and hence avoids potential problem of excessive mover temperature and risk of demagnetization.

  8. [Measurement of plasma parameters in slot microplasma by optical emission spectrum].

    Science.gov (United States)

    Dong, Li-Fang; Lü, Ying-Hui; Liu, Wei-Yuan; Yue, Han; Lu, Ning; Li, Xin-Chun

    2010-12-01

    Slot microplasma was generated in argon and air mixture by using dielectric barrier discharge device with two parallel water electrodes. The molecular vibrational temperature, molecular rotational temperature and average electron energy of the slot plasma were studied by optical emission spectrum. The molecular vibrational temperature was calculated using the second positive system of nitrogen molecules ( C3 pi(u) --> B3 pi(g)). The molecular rotational temperature was calculated using the first negative system of nitrogen molecular ions ( B 2sigma(u)+ --> X sigma(g)+). The relative intensities of the first negative system of nitrogen molecular ions (391.4 nm) and nitrogen molecules in the excitation level (337.1 nm) emission spectrum line were measured for studying the variations of electron energy. It was found that the molecular vibrational temperature, molecular rotational temperature and average electron energy decrease with gas pressure increasing.

  9. A wideband slotted kicker design for SPS transverse intra-bunch feedback

    CERN Document Server

    Cesaratto, J M; Rivetta, C H; Alesini, D; Gallo, A; Zobov, M; De Santis, S; Hofle, W

    2014-01-01

    In order for the SPS to meet the beam intensity demands for the HL-LHC upgrade, control and mitigation of trans- verse beam instabilities caused by electron cloud and TMCI will be essential. For this purpose a wideband intra-bunch feedback method has been proposed, based on a 4 GS/s front end data acquisition and processing, and on a back end frequency response extending to at least 1 GHz. A slotted type kicker, similar to those used for stochastic cooling, as well as an array of stripline kickers have been considered as the terminal elements of the feedback system. A slotted TEM type kicker has been designed fulfilling the bandwidth and kick strength requirements for the SPS application. In this paper we present an updated version of the design and electromagnetic characteristics, leading into the mechanical design and construction of the kicker occurring later this year.

  10. Theoretical examination of the slot channel waveguide configured in a cylindrically symmetric dielectric ring profile

    Science.gov (United States)

    Gauthier, Robert C.; Alzahrani, Mohammed A.; Jafari, Seyed Hamed

    2014-10-01

    It has recently been experimentally demonstrated that slot channel waveguides, configured in cylindrical space, can support high azimuthal order modes similar to whispering-gallery modes. This paper presents a mode solver based on Maxwell's vector wave equation for the electric field cast into an eigenvalue problem using a Fourier-Bessel basis function space. The modal frequencies and field profiles of the high azimuthal order slot-channel-whispering-gallery (SCWG) modes are computed for a set of nanometer spaced silicon rings supported by oxide. The computations show, that in addition to the traditionally observed, lowest order mode, the structure may support higher order SCWG modes. We complete the analysis by computing structures response as an ambient medium index of refraction sensor which achieves over 400 nm per RIU sensitivity.

  11. Compact SOI optimized slot microring coupled phase-shifted Bragg grating resonator for sensing

    Science.gov (United States)

    Zhao, Chao Ying; Zhang, Lei; Zhang, Cheng Mei

    2018-05-01

    We propose a novel sensor structure composed of a slot microring and a phase-shifted sidewall Bragg gratings in a slot waveguide. We first present a theoretical analysis of transmission by using the transfer matrix. Then, the mode-field distributions of transmission spectrum obtained from 3D simulations based on FDTD method demonstrates that our sensor exhibit theoretical sensitivity of 297 . 13 nm / RIU, a minimum detection limit of 1 . 1 × 10-4 RIU, the maximum extinction ratio of 20 dB, the quality factor of 2 × 103 and a compact dimension-theoretical structure of 15 μm × 8 . 5 μm. Finally, the sensor's performance is simulated for NaCl solution.

  12. Light scattering of rectangular slot antennas: parallel magnetic vector vs perpendicular electric vector.

    Science.gov (United States)

    Lee, Dukhyung; Kim, Dai-Sik

    2016-01-07

    We study light scattering off rectangular slot nano antennas on a metal film varying incident polarization and incident angle, to examine which field vector of light is more important: electric vector perpendicular to, versus magnetic vector parallel to the long axis of the rectangle. While vector Babinet's principle would prefer magnetic field along the long axis for optimizing slot antenna function, convention and intuition most often refer to the electric field perpendicular to it. Here, we demonstrate experimentally that in accordance with vector Babinet's principle, the incident magnetic vector parallel to the long axis is the dominant component, with the perpendicular incident electric field making a small contribution of the factor of 1/|ε|, the reciprocal of the absolute value of the dielectric constant of the metal, owing to the non-perfectness of metals at optical frequencies.

  13. Jupiter as a candidate source for >30 MeV electrons in Earth's slot region

    Science.gov (United States)

    O'Brien, T. P., III; Mazur, J. E.; Looper, M. D.

    2016-12-01

    The Relativistic Proton Spectrometer (RPS) on NASA's Van Allen Probes indicates the presence of >30 MeV leptons in the slot region (L 2) near Earth. We investigate the possibility that these are electrons originating at Jupiter. We account for two physical processes inside the radiation belts: inward radial transport that conserves the first and second adiabatic invariants, and synchrotron energy loss as the electrons reach super-relativistic energies (10s MeV). For our boundary condition outside the radiation belts, we use published spectra of Jovian electrons at 1 AU for conditions of good and poor magnetic connection between Earth and Jupiter. We simulate the >30 MeV spectrum and compare it with the RPS data to assess the plausibility of a Jovian source for the super-relativistic leptons in the slot.

  14. Multiband Slot-Based Dual Composite Right/Left-Handed Transmission Line

    Directory of Open Access Journals (Sweden)

    E. Abdo-Sanchez

    2012-10-01

    Full Text Available A dual Composite Right-/Left-Handed Transmission Line (CRLH TL implementation that presents multiband behaviour is proposed in this contribution. The artificial TL is realized by loading a host microstrip line with alternate rectangular stubs and slots. The required series and shunt immittances are respectively provided by the slot and the stub. Due to the distributed nature of these immittances, the resultant phase response presents theoretically infinite RH and LH alternate bands, thus being appropriate for multiband applications. The design methodology is described with the help of a proposed TLs-based equivalent circuit and highlights the simplicity for balance condition. Full wave simulated results of the dispersion characteristics and frequency response of a unit-cell and a three-cells structure are presented.

  15. PIV and LIF study of slot continuous jet at low Reynolds number

    Directory of Open Access Journals (Sweden)

    Broučková Zuzana

    2016-01-01

    Full Text Available This study deals with a continuous jet issuing from a small narrow slot with a width of 0.36 mm. The experimental arrangement is based on the piezoelectric synthetic jet actuator studied previously for easy comparisons. The working fluid is water at room temperature. The experiments were performed using methods of particle image velocimetry (PIV and flow visualization (laser induced fluorescence, LIF. The time-mean volume flux through the exit nozzle was quantified using precise scales. The mean velocity and the Reynolds number were evaluated as Um = 0.12 m/s and Re = 90, respectively. The results of LIF and PIV techniques revealed the three-dimensional character of the flow field, namely the saddle-shape velocity profiles. This behavior is typical for steady jets from a rectangular nozzle. The obtained results were compared with previous measurements of the synthetic jet issuing from the same cavity and the slot nozzle.

  16. Planar Task Space Control of a Biarticular Manipulator Driven by Spiral Motors

    Directory of Open Access Journals (Sweden)

    Ahmad Zaki bin Hj Shukor

    2012-10-01

    Full Text Available This paper elaborates upon a musculoskeletal-inspired robot manipulator using a prototype of the spiral motor developed in our laboratory. The spiral motors represent the antagonistic muscles due to the high forward/backward drivability without any gears or mechanisms. Modelling of the biarticular structure with spiral motor dynamics was presented and simulations were carried out to compare two control methods, Inverse Kinematics (IK and direct-Cartesian control, between monoarticular only structures and biarticular structures using the spiral motor. The results show the feasibility of the control, especially in maintaining air gaps within the spiral motor.

  17. Microstructure-Fracture Behavior Relationships of Slot-Welded Rail Steels

    Science.gov (United States)

    Allie, Aldinton; Aglan, Heshmat; Fateh, Mahmood

    2011-09-01

    Microstructural analyses of the parent pearlitic and bainitic rail steels were performed, and the results were compared with the microstructure of the welded pearlitic and bainitic steels. An increase in the ASTM grain size number of the heat-affected zone (HAZ) for both pearlitic and bainitic slot welds was observed. The microstructural features that were identified in the weldment of both slot-welded steels were very similar. This was expected since the same welding wire was used to weld both rail steels. The weld consisted of mainly ferrite and had similar grain size. The fusion zones of the welded pearlitic and bainitic rail steels were examined after flexural tests to determine if there were any cracks present due to improper or weak fusion. Examination of the entire fusion zone under high optical magnification revealed no cracks, indicating that a perfect fusion was achieved. The three-point flexural behavior of the parent pearlitic and bainitic steels was evaluated and compared with that of the slot-welded steels. It was found that that the welded pearlitic steel has superior fracture resistance properties when compared to the parent pearlitic steel. The average fracture resistance of the parent pearlitic steel was 79 MPa√m compared to 119 MPa√m for the welded pearlitic steel. The slot-welded bainitic steel, however, showed similar fracture resistance properties to the parent bainitic steel with average values of 121 and 128 MPa√m, respectively. The failure mechanism of the welded and parent pearlitic and bainitic steels was also identified. Microvoid coalescence was observed in both welded rail steel samples. This was manifested by dimpled features, which are associated with ductile failure.

  18. Analytical and hybrid methods in the theory of slot-hole coupling of electrodynamic volumes

    CERN Document Server

    Katrich, Victor A; Berdnik, Sergey L; Berdnik, Sergey L

    2008-01-01

    Narration of the text is both laconic and visually accessible, providing the reader with the possibility of rapid study and application of methods of computer analysis of electrodynamic problemsThe book is aimed at university professors, researchers and those specialists who are interested in theory and practical analysis of waveguide devices and systems using slot coupling elementsTopics included in the book are directly based on the original research results obtained by the authors and otherwise unknown earlier.

  19. Application of fractional-slot concentrated windings to synchronous reluctance motors.

    OpenAIRE

    Spargo, C.M.; Mecrow, B.C.; Widmer, J.D.; Morton, C.

    2015-01-01

    This paper presents an investigation into the application of fractional-slot concentrated windings to synchronous reluctance motors. The advantages and disadvantages of the synthesis of such a machine are explored with thermal aspects included, and a comparison with a similar topology, i.e., the switched reluctance motor, is also presented where appropriate. The differences in electric drive between the two reluctance motors are briefly explored. Finite element studies show that the fractiona...

  20. Radio-Frequency design of a Lower Hybrid Slotted Waveguide Antenna.

    Czech Academy of Sciences Publication Activity Database

    Helou, W.; Goniche, M.; Hillairet, J.; Žáček, František; Achard, J.; Adámek, Jiří; Bogár, Ondrej; Mollard, P.; Pascal, J.-Y.; Poli, S.; Šesták, David; Volpe, R.; Zajac, Jaromír

    2017-01-01

    Roč. 123, November (2017), s. 223-227 ISSN 0920-3796. [SOFT 2016: Symposium on Fusion Technology /29./. Prague, 05.09.2016-09.09.2016] Institutional support: RVO:61389021 Keywords : Lower Hybrid Current Drive * Slotted Waveguide Antenna * Phased arrays Subject RIV: JF - Nuclear Energetics OBOR OECD: Nuclear related engineering Impact factor: 1.319, year: 2016 https://www.sciencedirect.com/science/article/pii/S0920379617304076

  1. Study of Wave Conditions at Kvitsøy Prototype Location of Seawave Slot-Cone Generator

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Guinot, Florent

    This report presents the results of a study of the wave conditions at the planned location of the prototype of the wave energy converter (WEC) Seawave Slot-Cone Generator (SSG). SSG is a WEC utilizing wave overtopping in multiple reservoirs.......This report presents the results of a study of the wave conditions at the planned location of the prototype of the wave energy converter (WEC) Seawave Slot-Cone Generator (SSG). SSG is a WEC utilizing wave overtopping in multiple reservoirs....

  2. A Minimax Network Flow Model for Characterizing the Impact of Slot Restrictions

    Science.gov (United States)

    Lee, Douglas W.; Patek, Stephen D.; Alexandrov, Natalia; Bass, Ellen J.; Kincaid, Rex K.

    2010-01-01

    This paper proposes a model for evaluating long-term measures to reduce congestion at airports in the National Airspace System (NAS). This model is constructed with the goal of assessing the global impacts of congestion management strategies, specifically slot restrictions. We develop the Minimax Node Throughput Problem (MINNTHRU), a multicommodity network flow model that provides insight into air traffic patterns when one minimizes the worst-case operation across all airports in a given network. MINNTHRU is thus formulated as a model where congestion arises from network topology. It reflects not market-driven airline objectives, but those of a regulatory authority seeking a distribution of air traffic beneficial to all airports, in response to congestion management measures. After discussing an algorithm for solving MINNTHRU for moderate-sized (30 nodes) and larger networks, we use this model to study the impacts of slot restrictions on the operation of an entire hub-spoke airport network. For both a small example network and a medium-sized network based on 30 airports in the NAS, we use MINNTHRU to demonstrate that increasing the severity of slot restrictions increases the traffic around unconstrained hub airports as well as the worst-case level of operation over all airports.

  3. Artificial Material Integrated Ultra-wideband Tapered Slot Antenna for Gain Enhancement with Band Notch Characteristics

    Directory of Open Access Journals (Sweden)

    R. Singha

    2018-04-01

    Full Text Available The gain of the ultra-wideband tapered slot antenna (TSA is enhanced by using broadband artificial material with band notch characteristics. The proposed artificial material unit cell is designed by fabricating non-resonant three S-shaped parallel metallic line on single side of the dielectric substrate which provides a longer current path compared to the parallel-line structure. The proposed S-shaped structure is printed on the top side of the tapered slot antenna in the extended substrate periodically. The effective refractive index of the artificial material is lower than antenna substrate and phase velocity in the region of artificial material is much higher than the other region. Therefore, the proposed artificial material acts like a beam focusing lens. The band notch at 5.5 GHz is achieved by creating a split ring resonator (SRR slot near the balun. The basic and artificial material loaded TSAs are fabricated and the measurement results show that the gain of the basic antenna has been increased by 1.6 dBi. At the same time, the proposed antenna achieves a VSWR below 2 from 3 to 11 GHz except at 5.5 GHz with a notch band from 5.1 to 5.8 GHz for band rejection of wireless local area network (WLAN application.

  4. Power and time slot allocation in cognitive relay networks using particle swarm optimization.

    Science.gov (United States)

    Derakhshan-Barjoei, Pouya; Dadashzadeh, Gholamreza; Razzazi, Farbod; Razavizadeh, S Mohammad

    2013-01-01

    The two main problems in cognitive radio networks are power and time slot allocation problems which require a precise analysis and guarantee the quality of service in both the primary and secondary users. In this paper, these two problems are considered and a method is proposed to solve the resulting optimization problem. Our proposed method provides an improved performance in solving the constrained nonlinear multiobject optimization for the power control and beamforming in order to reach the maximum capacity and proper adaption of time slots, and as a result a new scheme for joint power and time slot allocation in cognitive relay networks is proposed. We adopt space diversity access as the secondary users access scheme and divide the time between multiple secondary users according to their contribution to primary user's transmission. Helping primary users provides more opportunities for secondary users to access the channel since the primary users can release the channel sooner. In contrast, primary network leases portion of channel access time to the secondary users for their transmission using particle swarm optimization (PSO). Numerical studies show good performance of the proposed scheme with a dynamic cost function in a nonstationary environment.

  5. Brain cells in the avian 'prefrontal cortex' code for features of slot-machine-like gambling.

    Directory of Open Access Journals (Sweden)

    Damian Scarf

    2011-01-01

    Full Text Available Slot machines are the most common and addictive form of gambling. In the current study, we recorded from single neurons in the 'prefrontal cortex' of pigeons while they played a slot-machine-like task. We identified four categories of neurons that coded for different aspects of our slot-machine-like task. Reward-Proximity neurons showed a linear increase in activity as the opportunity for a reward drew near. I-Won neurons fired only when the fourth stimulus of a winning (four-of-a-kind combination was displayed. I-Lost neurons changed their firing rate at the presentation of the first nonidentical stimulus, that is, when it was apparent that no reward was forthcoming. Finally, Near-Miss neurons also changed their activity the moment it was recognized that a reward was no longer available, but more importantly, the activity level was related to whether the trial contained one, two, or three identical stimuli prior to the display of the nonidentical stimulus. These findings not only add to recent neurophysiological research employing simulated gambling paradigms, but also add to research addressing the functional correspondence between the avian NCL and primate PFC.

  6. Report for slot cutter proof-of-principle test, Buried Waste Containment System project. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-05-21

    Several million cubic feet of hazardous and radioactive waste was buried in shallow pits and trenches within many US Department of Energy (US DOE) sites. The pits and trenches were constructed similarly to municipal landfills with both stacked and random dump waste forms such as barrels and boxes. Many of the hazardous materials in these waste sites are migrating into groundwater systems through plumes and leaching. On-site containment is one of the options being considered for prevention of waste migration. This report describes the results of a proof-of-principle test conducted to demonstrate technology for containing waste. This proof-of-principle test, conducted at the RAHCO International, Inc., facility in the summer of 1997, evaluated equipment techniques for cutting a horizontal slot beneath an existing waste site. The slot would theoretically be used by complementary equipment designed to place a cement barrier under the waste. The technology evaluated consisted of a slot cutting mechanism, muck handling system, thrust system, and instrumentation. Data were gathered and analyzed to evaluate the performance parameters.

  7. Report for slot cutter proof-of-principle test, Buried Waste Containment System project. Revision 1

    International Nuclear Information System (INIS)

    1998-01-01

    Several million cubic feet of hazardous and radioactive waste was buried in shallow pits and trenches within many US Department of Energy (US DOE) sites. The pits and trenches were constructed similarly to municipal landfills with both stacked and random dump waste forms such as barrels and boxes. Many of the hazardous materials in these waste sites are migrating into groundwater systems through plumes and leaching. On-site containment is one of the options being considered for prevention of waste migration. This report describes the results of a proof-of-principle test conducted to demonstrate technology for containing waste. This proof-of-principle test, conducted at the RAHCO International, Inc., facility in the summer of 1997, evaluated equipment techniques for cutting a horizontal slot beneath an existing waste site. The slot would theoretically be used by complementary equipment designed to place a cement barrier under the waste. The technology evaluated consisted of a slot cutting mechanism, muck handling system, thrust system, and instrumentation. Data were gathered and analyzed to evaluate the performance parameters

  8. Assessment of the dimensions and surface characteristics of orthodontic wires and bracket slots

    Directory of Open Access Journals (Sweden)

    Gabriel Schmidt Dolci

    2013-04-01

    Full Text Available OBJECTIVE: The purpose of this study was to evaluate the dimensions and surface characteristics of orthodontic wires and bracket slots of different commercial brands. METHODS: Thirty metallic brackets (0.022 x 0.028-in and 0.022 x 0.030-in were divided in three groups: DYN/3M group = Dyna-Lock, 3M/Unitek (stainless steel, or SS; STD/MO group = Slim Morelli (SS; and Ni-Free/MO group = Slim Morelli (Ni-Free. The stainless steel wires (0.019 x 0.025in were divided into two groups: MO group = Morelli; and 3M group = 3M/Unitek. The bracket and wire measurements were done by two methods: (a Surface Electron Microscopy (SEM, and (b Profile projection. The surface analysis was done qualitatively, based on SEM images and/or by a rugosimeter. The quantitative results were analyzed by ANOVA with Tukey's test (p < 0.05 and Student's t test. RESULTS: A significant difference in the dimensions of slots was observed, and the NiFree/MO group showed the greatest changes when compared to the other groups. The analysis of surface topography of the brackets indicated greater homogeneity of the metallic matrix for DYN/3M and STD/MO groups. As for the dimensions of the wires, groups showed statistically different mean heights. CONCLUSIONS: It was concluded that wires and brackets slots can present altered dimensions, which might directly and unintentionally affect the planned tooth movement.

  9. Design of Ultra-Wideband Tapered Slot Antenna by Using Binomial Transformer with Corrugation

    Science.gov (United States)

    Chareonsiri, Yosita; Thaiwirot, Wanwisa; Akkaraekthalin, Prayoot

    2017-05-01

    In this paper, the tapered slot antenna (TSA) with corrugation is proposed for UWB applications. The multi-section binomial transformer is used to design taper profile of the proposed TSA that does not involve using time consuming optimization. A step-by-step procedure for synthesis of the step impedance values related with step slot widths of taper profile is presented. The smooth taper can be achieved by fitting the smoothing curve to the entire step slot. The design of TSA based on this method yields results with a quite flat gain and wide impedance bandwidth covering UWB spectrum from 3.1 GHz to 10.6 GHz. To further improve the radiation characteristics, the corrugation is added on the both edges of the proposed TSA. The effects of different corrugation shapes on the improvement of antenna gain and front-to-back ratio (F-to-B ratio) are investigated. To demonstrate the validity of the design, the prototypes of TSA without and with corrugation are fabricated and measured. The results show good agreement between simulation and measurement.

  10. Mid-infrared refractive index sensing using optimized slotted photonic crystal waveguides

    Science.gov (United States)

    Kassa-Baghdouche, Lazhar; Cassan, Eric

    2018-02-01

    Slotted photonic crystal waveguides (SPCWs) were designed to act as refractive index sensing devices at mid-infrared (IR) wavelengths around λ = 3.6 μm. In particular, effort was made to engineer the input and output slot waveguide interfaces in order to increase the effective sensitivity through resonant tapering. A slotted PhC waveguide immersed in air and liquid cladding layers was considered. To determine the performance of the sensor, the sensitivity of the device was estimated by calculating the shift in the upper band edge of the output transmission spectrum. The results showed that the sensitivity of a conventionally designed SPCW followed by modifications in the structure parameter yielded a 510 nm shift in the wavelength position of the upper band edge, indicating a sensitivity of more than 1150 nm per refractive index unit (RIU) with an insertion loss level of -0.3 dB. This work demonstrates the viability of photonic crystal waveguide high sensitivity devices in the Mid-IR, following a transposition of the concepts inherited from the telecom band and an optimization of the design, in particular a minimization of photonic device insertion losses.

  11. Two-Slotted Surface Coil Array for Magnetic Resonance Imaging at 4 Tesla

    International Nuclear Information System (INIS)

    Solis, S. E.; Hernandez, J. A.; Rodriguez, A. O.; Tomasi, D.

    2008-01-01

    Arrays of antennas have been widely accepted for magnetic resonance imaging applications due to their high signal-to-noise ratio (SNR) over large volumes of interest. A new surface coil based on the magnetron tube and called slotted surface coil, has been recently introduced by our group. This coil design experimentally demonstrated a significant improvement over the circular-shaped coil when used in the receive-only mode. The slotted coils formed a two-sheet structure with a 90 deg. separation and each coil had 6 circular slots. Numerical simulations were performed using the finite element method for this coil design to study the behaviour of the array magnetic field. Then, we developed a two-coil array for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. In vitro images showed the feasibility of this coil array for standard pulses for high field magnetic resonance imaging

  12. Wind-tunnel tests on model wing with Fowler flap and specially developed leading-edge slot

    Science.gov (United States)

    Weick, Fred E; Platt, Robert C

    1933-01-01

    An investigation was made in the NACA 7 by 10 foot wind tunnel to find the increase in maximum lift coefficient which could be obtained by providing a model wing with both a Fowler trailing-edge extension flap and a Handley Page type leading-edge slot. A conventional Handley page slot proportioned to operate on the plain wing without a flap gave but a slight increase with the flap; so a special form of slot was developed to work more effectively with the flap. With the best combined arrangement the maximum lift coefficient based on the original area was increased from 3.17, for the Fowler wing, to 3.62. The minimum drag coefficient with both devices retracted was increased in approximately the same proportion. Tests were also made with the special-type slot on the plain wing without the flap. The special slot, used either with or without the Fowler flap, gave definitely higher values of the maximum lift coefficient than the slots of conventional form, with an increase of the same order in the minimum drag coefficient.

  13. Numerical exploration of non-axisymmetric divertor closure in the small angle slot (SAS) divertor at DIII-D

    Science.gov (United States)

    Frerichs, H.; Schmitz, O.; Covele, B.; Feng, Y.; Guo, H. Y.; Hill, D.

    2018-05-01

    Numerical simulations of toroidal asymmetries in a tightly baffled small angle slot (SAS) divertor on the DIII-D tokamak show that toroidal asymmetries in divertor closure result in (non-axisymmetric) local onset of detachment within a density window of 10-15% on top of the nominal threshold separatrix density. The SAS divertor is explored at DIII-D for improving access to cold, dissipative/detached divertor conditions. The narrow width of the slot divertor coupled with a small magnetic field line-to-target angle facilitates the buildup of neutral density, thereby increasing radiative and neutrals-related (atoms and molecules) losses in the divertor. Small changes in the strike point location can be expected to have a large impact on divertor conditions. The combination of misaligned slot structure and non-axisymmetric perturbations to the magnetic field configuration causes the strike point to move along the divertor target plate, possibly leaving the divertor slot at some locations. The latter extreme case essentially introduces an opening in the divertor slot from where recycling neutrals can easily escape, and thereby degrade the performance of the slot divertor. Such a strike point dislocation is approximated by a finite gap in the divertor baffle for which 3D edge plasma and neutral gas simulations are performed with the EMC3-EIRENE code.

  14. Kinematic analyses of a cross-slot microchannel applicable to cell deformability measurement under inertial or viscoelastic flow

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ju Min [Ajou University, Suwon (Korea, Republic of)

    2015-12-15

    A cross-slot microchannel has been harnessed for a wide range of applications, such as label-free measurements of cell deformability and rheological characterization of complex fluids. This work investigates flow kinematics in a cross-slot microchannel used for the measurements of cell deformability utilizing finite element method (FEM)- based numerical simulation. In a cross-slot microchannel, the cell is stretched near the stagnation of the cross-slot channel, and cell deformation is significantly affected by its trajectory. Two passive methods, inertia- and viscoelasticitybased, which do not rely on any external force such as an electric field, have been applied to focus particles along the channel centerline so that the cell trajectories are unified. However, it is not well understood how the flow kinematics inside the cross-slot channel is altered by the inertial or viscoelastic effect when these two methods are employed. This work demonstrates that the flow kinematics such as the distributions of flow type and strain rate is notably changed with an increase in the Reynolds number when an inertia-based method is employed. On the other hand, flow kinematics does not significantly deviate from that of an inertia-less Newtonian fluid irrespective of the Weissenberg numbers when a viscoelasticity-based method is used. The current work will be helpful for the design and operation of a cross-slot microdevice for measuring cell deformability.

  15. STAR FORMATION IN PARTIALLY GAS-DEPLETED SPIRAL GALAXIES

    International Nuclear Information System (INIS)

    Rose, James A.; Miner, Jesse; Levy, Lorenza; Robertson, Paul

    2010-01-01

    Broadband B and R and Hα images have been obtained with the 4.1 m SOAR telescope atop Cerro Pachon, Chile, for 29 spiral galaxies in the Pegasus I galaxy cluster and for 18 spirals in non-cluster environments. Pegasus I is a spiral-rich cluster with a low-density intracluster medium and a low galaxy velocity dispersion. When combined with neutral hydrogen (H I) data obtained with the Arecibo 305 m radio telescope, acquired by Levy et al. (2007) and by Springob et al. (2005b), we study the star formation rates in disk galaxies as a function of their H I deficiency. To quantify H I deficiency, we use the usual logarithmic deficiency parameter, DEF. The specific star formation rate (SSFR) is quantified by the logarithmic flux ratio of Hα flux to R-band flux, and thus roughly characterizes the logarithmic SFR per unit stellar mass. We find a clear correlation between the global SFR per unit stellar mass and DEF, such that the SFR is lower in more H I-deficient galaxies. This correlation appears to extend from the most gas-rich to the most gas-poor galaxies. We also find a correlation between the central SFR per unit mass relative to the global values, in the sense that the more H I-deficient galaxies have a higher central SFR per unit mass relative to their global SFR values than do gas-rich galaxies. In fact, approximately half of the H I-depleted galaxies have highly elevated SSFRs in their central regions, indicative of a transient evolutionary state. In addition, we find a correlation between gas depletion and the size of the Hα disk (relative to the R-band disk); H I-poor galaxies have truncated disks. Moreover, aside from the elevated central SSFR in many gas-poor spirals, the SSFR is otherwise lower in the Hα disks of gas-poor galaxies than in gas-rich spirals. Thus, both disk truncation and lowered SSFR levels within the star-forming part of the disks (aside from the enhanced nuclear SSFR) correlate with H I deficiency, and both phenomena are found to

  16. Shadows and spirals in the protoplanetary disk HD 100453

    Science.gov (United States)

    Benisty, M.; Stolker, T.; Pohl, A.; de Boer, J.; Lesur, G.; Dominik, C.; Dullemond, C. P.; Langlois, M.; Min, M.; Wagner, K.; Henning, T.; Juhasz, A.; Pinilla, P.; Facchini, S.; Apai, D.; van Boekel, R.; Garufi, A.; Ginski, C.; Ménard, F.; Pinte, C.; Quanz, S. P.; Zurlo, A.; Boccaletti, A.; Bonnefoy, M.; Beuzit, J. L.; Chauvin, G.; Cudel, M.; Desidera, S.; Feldt, M.; Fontanive, C.; Gratton, R.; Kasper, M.; Lagrange, A.-M.; LeCoroller, H.; Mouillet, D.; Mesa, D.; Sissa, E.; Vigan, A.; Antichi, J.; Buey, T.; Fusco, T.; Gisler, D.; Llored, M.; Magnard, Y.; Moeller-Nilsson, O.; Pragt, J.; Roelfsema, R.; Sauvage, J.-F.; Wildi, F.

    2017-01-01

    Context. Understanding the diversity of planets requires studying the morphology and physical conditions in the protoplanetary disks in which they form. Aims: We aim to study the structure of the 10 Myr old protoplanetary disk HD 100453, to detect features that can trace disk evolution and to understand the mechanisms that drive these features. Methods: We observed HD 100453 in polarized scattered light with VLT/SPHERE at optical (0.6 μm, 0.8 μm) and near-infrared (1.2 μm) wavelengths, reaching an angular resolution of 0.02'', and an inner working angle of 0.09''. Results: We spatially resolve the disk around HD 100453, and detect polarized scattered light up to 0.42'' ( 48 au). We detect a cavity, a rim with azimuthal brightness variations at an inclination of 38° with respect to our line of sight, two shadows and two symmetric spiral arms. The spiral arms originate near the location of the shadows, close to the semi major axis. We detect a faint feature in the SW that can be interpreted as the scattering surface of the bottom side of the disk, if the disk is tidally truncated by the M-dwarf companion currently seen at a projected distance of 119 au. We construct a radiative transfer model that accounts for the main characteristics of the features with an inner and outer disk misaligned by 72°. The azimuthal brightness variations along the rim are well reproduced with the scattering phase function of the model. While spirals can be triggered by the tidal interaction with the companion, the close proximity of the spirals to the shadows suggests that the shadows could also play a role. The change in stellar illumination along the rim induces an azimuthal variation of the scale height that can contribute to the brightness variations. Conclusions: Dark regions in polarized images of transition disks are now detected in a handful of disks and often interpreted as shadows due to a misaligned inner disk. However, the origin of such a misalignment in HD 100453, and

  17. PIV study of large-scale flow organisation in slot jets

    International Nuclear Information System (INIS)

    Shestakov, Maxim V.; Dulin, Vladimir M.; Tokarev, Mikhail P.; Sikovsky, Dmitrii Ph.; Markovich, Dmitriy M.

    2015-01-01

    Highlights: • Volumetric velocity measurements are perfumed by PIV to analyse 3D flow organisation in a slot jet. • Proper orthogonal decomposition is used to extract coherent flow motion. • Movement of quasi-two-dimensional large-scale vortices is associated with jet meandering. • Amplitude of jet meandering is found to be aperiodically modulated. • Secondary longitudinal vortex rolls are important for cross-stream mixing and momentum transfer. - Abstract: The paper reports on particle image velocimetry (PIV) measurements in turbulent slot jets bounded by two solid walls with the separation distance smaller than the jet width (5–40%). In the far-field such jets are known to manifest features of quasi-two dimensional, two component turbulence. Stereoscopic and tomographic PIV systems were used to analyse local flows. Proper orthogonal decomposition (POD) was applied to extract coherent modes of the velocity fluctuations. The measurements were performed both in the initial region close to the nozzle exit and in the far fields of the developed turbulent slot jets for Re ⩾ 10,000. A POD analysis in the initial region indicates a correlation between quasi-2D vortices rolled-up in the shear layer and local flows in cross-stream planes. While the near-field turbulence shows full 3D features, the wall-normal velocity fluctuations day out gradually due to strong wall-damping resulting in an almost two-component turbulence. On the other hand, the longitudinal vortex rolls take over to act as the main agents in wall-normal and spanwise mixing and momentum transfer. The quantitative analysis indicates that the jet meandering amplitude was aperiodically modulated when arrangement of the large-scale quasi-2D vortices changed between asymmetric and symmetric pattern relatively to the jet axis. The paper shows that the dynamics of turbulent slot jets are more complex than those of 2D, plane and rectangular 3D jets. In particular, the detected secondary longitudinal

  18. Fractional-Slot Surface Mounted PM Motors with Concentrated Windings for HEV Traction Drives

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, J.M.

    2005-10-24

    High-power density and efficiency resulting from elimination of rotor windings and reduced magnetic-flux losses have made the rare earth permanent magnet (PM) motor a leading candidate for the Department of Energy's Office of FreedomCAR and Vehicle Technologies (FCVTs) traction drive motor. These traction drives are generally powered by radial-gap motors, having the magnets on or embedded in a rotating cylinder separated from the inside surface of a slotted cylindrical stator by an annular gap. The two main types of radial-gap PM rotors are those with magnets mounted on the surface of a supporting back iron, called PM surface mounted (PMSM) motors, and those with magnets mounted in slots in the rotor, called interior PM (IPM) motors. Most early PM motor research was on the PMSM motor, which was thought to have an inherently low stator inductance. A low stator inductance can lead to currents dangerously exceeding rated current as the back-emf across the inductance increases with speed; consequently, part of the attempted solution has been to increase the stator inductance to reduce the rate of current rise. Although analysis suggested that there should be no problem designing sufficiently high stator inductance into PMSMs, attempts to do so were often not successful and a motor design was sought that would have a higher intrinsic inductance. Commercial research at Toyota has focused on IPM motors because they can achieve a high-saliency ratio, which helps them operate over a high constant power speed ratio (CPSR), but they are more difficult to fabricate. The Oak Ridge National Laboratory's (ORNL) position has been to continue research on brushless direct current (dc) motors (BDCMs) because of ease of fabrication and increased power output. Recently there has been a revival of interest in a fractional-slot PMSMs [15] made with concentrated windings because they possess three important features. First, they can increase the motor's inductance

  19. Curvature-driven bubbles or droplets on the spiral surface

    Science.gov (United States)

    Li, Shanpeng; Liu, Jianlin; Hou, Jian

    2016-11-01

    Directional motion of droplets or bubbles can often be observed in nature and our daily life, and this phenomenon holds great potential in many engineering areas. The study shows that droplets or bubbles can be driven to migrate perpetually on some special substrates, such as the Archimedean spiral, the logarithmic spiral and a cantilever sheet in large deflection. It is found that a bubble approaches or deviates from the position with highest curvature of the substrate, when it is on the concave or convex side. This fact is helpful to explain the repelling water capability of Nepenthes alata. Based on the force and energy analysis, the mechanism of the bubble migration is well addressed. These findings pave a new way to accurately manipulate droplet or bubble movement, which bring inspirations to the design of microfluidic and water harvesting devices, as well as oil displacement and ore filtration.

  20. Synchronized control of spiral CT scan for security inspection device

    International Nuclear Information System (INIS)

    Wang Jue; Jiang Zenghui; Wang Fuquan

    2008-01-01

    In security inspection system of spiral CT, the synchronization between removing and rotating, and the scan synchronization between rotating and sampling influence quality of image reconstruction, so it is difficulty and important that how to realize synchronized scan. According to the controlling demand of multi-slice Spiral CT, the method to realize synchronized scan is given. a synchronized control system is designed, in which we use a industrial PC as the control computer, use magnetic grids as position detectors, use alternating current servo motor and roller motor as drivers respectively drive moving axis and rotating axis. This method can solve the problem of synchronized scan, and has a feasibility and value of use. (authors)

  1. Status of the SPIRAL 2 LINAC cryogenic system

    Science.gov (United States)

    Ghribi, A.; Bernaudin, P.-E.; Vassal, A.; Bonne, F.

    2017-07-01

    SPIRAL 2 is a state of the art superconducting linear accelerator expected to deliver some of the highest intensity rare isotope beams on earth. The project has been in development/design, fabrication and installation for over 10 years and is now reaching its final critical stages before commissioning. One of its most critical parts is a cryoplant and a cryodistribution system that feed the heart of the accelerator with the necessary refrigeration power and allow the required pressure and thermal regulation to be achieved and maintained in a reliable way. This paper summarises the latest updates of the cryogenic system before the first cool down trials. It also plots the strategies and R&D efforts undertaken to tackle some of the challenges that SPIRAL 2 is expected to face.

  2. Distributed temperature sensing using a SPIRAL configuration ultrasonic waveguide

    Science.gov (United States)

    Periyannan, Suresh; Balasubramaniam, Krishnan

    2017-02-01

    Distributed temperature sensing has important applications in the long term monitoring of critical enclosures such as containment vessels, flue gas stacks, furnaces, underground storage tanks and buildings for fire risk. This paper presents novel techniques for such measurements, using wire in a spiral configuration and having special embodiments such a notch for obtaining wave reflections from desired locations. Transduction is performed using commercially available Piezo-electric crystal that is bonded to one end of the waveguide. Lower order axisymmetric guided ultrasonic modes were employed. Time of fight (TOF) differences between predefined reflectors located on the waveguides are used to infer temperature profile in a chamber with different temperatures. The L(0,1) wave mode (pulse echo approach) was generated/received in a spiral waveguide at different temperatures for this work. The ultrasonic measurements were compared with commercially available thermocouples.

  3. The Norma spiral arm: large-scale pitch angle

    Science.gov (United States)

    Vallée, Jacques P.

    2017-09-01

    In the inner Galaxy, we statistically find the mean pitch angle of the recently mapped Norma arm in two galactic quadrants (observed tangentially at galactic longitudes near l=328° and near l=20°), using the twin-tangent method, and obtain -13.7°± 1.4°. We compared with other measurements in the literature. Also, using the latest published data on pitch angle and the latest published data on the radial starting point of the four arms (R_{Gal} = 2.2 kpc) in each galactic quadrant, a revised velocity plot of the Norma spiral arm is made, along with other spiral arms in the Milky Way, in each Galactic quadrant.

  4. Spiral actin-polymerization waves can generate amoeboidal cell crawling

    Energy Technology Data Exchange (ETDEWEB)

    Dreher, A.; Aranson, I. S.; Kruse, K.

    2014-05-01

    Amoeboidal cell crawling on solid substrates is characterized by protrusions that seemingly appear randomly along the cell periphery and drive the cell forward. For many cell types, it is known that the protrusions result from polymerization of the actin cytoskeleton. However, little is known about how the formation of protrusions is triggered and whether the appearance of subsequent protrusions is coordinated. Recently, the spontaneous formation of actin-polymerization waves was observed. These waves have been proposed to orchestrate the cytoskeletal dynamics during cell crawling. Here, we study the impact of cytoskeletal polymerization waves on cell migration using a phase-field approach. In addition to directionally moving cells, we find states reminiscent of amoeboidal cell crawling. In this framework, new protrusions are seen to emerge from a nucleation process, generating spiral actin waves in the cell interior. Nucleation of new spirals does not require noise, but occurs in a state that is apparently displaying spatio-temporal chaos.

  5. Heating hydrocarbon containing formations in a spiral startup staged sequence

    Science.gov (United States)

    Vinegar, Harold J [Bellaire, TX; Miller, David Scott [Katy, TX

    2009-12-15

    Methods for treating a hydrocarbon containing formation are described herein. Methods may include treating a first zone of the formation. Treatment of a plurality of zones of the formation may be begun at selected times after the treatment of the first zone begins. The treatment of at least two successively treated zones may begin at a selected time after treatment of the previous zone begins. At least two of the successively treated zones may be adjacent to the zone treated previously. The successive treatment of the zones proceeds in an outward, substantially spiral sequence from the first zone so that the treatment of the zones may move substantially spirally outwards towards a boundary of the treatment area.

  6. Chiral spiral induced by a strong magnetic field

    Directory of Open Access Journals (Sweden)

    Abuki Hiroaki

    2016-01-01

    Full Text Available We study the modification of the chiral phase structure of QCD due to an external magnetic field. We first demonstrate how the effect of magnetic field can systematically be incorporated into a generalized Ginzburg-Landau framework. We then analyze the phase structure in the vicinity of the chiral critical point. In the chiral limit, the effect is found to be so drastic that it brings a “continent” of chiral spiral in the phase diagram, by which the chiral tricritical point is totally washed out. This is the case no matter how small the intensity of magnetic field is. On the other hand, the current quark mass protects the chiral critical point from a weak magnetic field. However, the critical point will eventually be covered by the chiral spiral phase as the magnetic field grows.

  7. Heat transfer studies on spiral plate heat exchanger

    Directory of Open Access Journals (Sweden)

    Rajavel Rangasamy

    2008-01-01

    Full Text Available In this paper, the heat transfer coefficients in a spiral plate heat exchanger are investigated. The test section consists of a plate of width 0.3150 m, thickness 0.001 m and mean hydraulic diameter of 0.01 m. The mass flow rate of hot water (hot fluid is varying from 0.5 to 0.8 kg/s and the mass flow rate of cold water (cold fluid varies from 0.4 to 0.7 kg/s. Experiments have been conducted by varying the mass flow rate, temperature, and pressure of cold fluid, keeping the mass flow rate of hot fluid constant. The effects of relevant parameters on spiral plate heat exchanger are investigated. The data obtained from the experimental study are compared with the theoretical data. Besides, a new correlation for the Nusselt number which can be used for practical applications is proposed.

  8. Spiral and Rotor Patterns Produced by Fairy Ring Fungi

    Science.gov (United States)

    Karst, N.; Dralle, D.; Thompson, S. E.

    2015-12-01

    Soil fungi fill many essential ecological and biogeochemical roles, e.g. decomposing litter, redistributing nutrients, and promoting biodiversity. Fairy ring fungi offer a rare glimpse into the otherwise opaque spatiotemporal dynamics of soil fungal growth, because subsurface mycelial patterns can be inferred from observations at the soil's surface. These observations can be made directly when the fungi send up fruiting bodies (e.g., mushrooms and toadstools), or indirectly via the effect the fungi have on neighboring organisms. Grasses in particular often temporarily thrive on the nutrients liberated by the fungus, creating bands of rich, dark green turf at the edge of the fungal mat. To date, only annular (the "ring" in fairy ring) and arc patterns have been described in the literature. We report observations of novel spiral and rotor pattern formation in fairy ring fungi, as seen in publically available high-resolution aerial imagery of 22 sites across the continental United States. To explain these new behaviors, we first demonstrate that a well-known model describing fairy ring formation is equivalent to the Gray-Scott reaction-diffusion model, which is known to support a wide range of dynamical behaviors, including annular traveling waves, rotors, spirals, and stable spatial patterns including spots and stripes. Bifurcation analysis and numerical simulation are then used to define the region of parameter space that supports spiral and rotor formation. We find that this region is adjacent to one within which typical fairy rings develop. Model results suggest simple experimental procedures that could potentially induce traditional ring structures to exhibit rotor or spiral dynamics. Intriguingly, the Gray-Scott model predicts that these same procedures could be used to solicit even richer patterns, including spots and stripes, which have not yet been identified in the field.

  9. Spiral model of procedural cycle of educational process management

    OpenAIRE

    Bezrukov Valery I.; Lukashina Elena V.

    2016-01-01

    The article analyzes the nature and characteristics of the spiral model Procedure educational systems management cycle. The authors identify patterns between the development of information and communication technologies and the transformation of the education management process, give the characteristics of the concept of “information literacy” and “Media Education”. Consider the design function, determine its potential in changing the traditional educational paradigm to the new - information....

  10. Scintigraphic diagnosis of spiral fracture in young children

    International Nuclear Information System (INIS)

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

    1988-01-01

    The authors report 8 cases of unsuspected bone fracture in children, identified at bone scan. 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 (sprial fracture of the tibia undisplaced), and the uniform of appearance the bone scan. These data confirm the value of the bone scan in limping children and suggest that spiral fracture of the tibia is a frequent and underdiagnosed condition in children [fr

  11. Spontaneous spiral formation in two-dimensional oscillatory media

    Science.gov (United States)

    Kettunen, Petteri; Amemiya, Takashi; Ohmori, Takao; Yamaguchi, Tomohiko

    1999-08-01

    Computational studies of pattern formation in a modified Oregonator model of the Belousov-Zhabotinsky reaction is described. Initially inactive two-dimensional reaction media with an immobilized catalyst is connected to a reservoir of fresh reactants through a set of discrete points distributed randomly over the interphase surface. It is shown that the diffusion of reactants combined with oscillatory reaction kinetics can give rise to spontaneous spiral formation and phase waves.

  12. Infrared emission and tidal interactions of spiral galaxies

    International Nuclear Information System (INIS)

    Byrd, G.G.

    1987-01-01

    Computer simulations of tidal interactions of spiral galaxies are used to attempt to understand recent discoveries about infrared (IR) emitting galaxies. It is found that the stronger tidal perturbation by a companion the more disk gas clouds are thrown into nucleus crossing orbits and the greater the velocity jumps crossing spiral arms. Both these tidally created characteristics would create more IR emission by high speed cloud collisions and more IR via effects of recently formed stars. This expectation at greater tidal perturbation matches the observation of greater IR emission for spiral galaxies with closer and/or more massive companions. The greater collision velocities found at stronger perturbations on the models will also result in higher dust temperature in the colliding clouds. In the IR pairs examined, most have only one member, the larger, detected and when both are detected, the larger is always the more luminous. In simulations and in a simple analytic description of the strong distance dependence of the tidal force, it is found that the big galaxy of a pair is more strongly affected than the small

  13. Ultra-precision turning of complex spiral optical delay line

    Science.gov (United States)

    Zhang, Xiaodong; Li, Po; Fang, Fengzhou; Wang, Qichang

    2011-11-01

    Optical delay line (ODL) implements the vertical or depth scanning of optical coherence tomography, which is the most important factor affecting the scanning resolution and speed. The spinning spiral mirror is found as an excellent optical delay device because of the high-speed and high-repetition-rate. However, it is one difficult task to machine the mirror due to the special shape and precision requirement. In this paper, the spiral mirror with titled parabolic generatrix is proposed, and the ultra-precision turning method is studied for its machining using the spiral mathematic model. Another type of ODL with the segmental shape is also introduced and machined to make rotation balance for the mass equalization when scanning. The efficiency improvement is considered in details, including the rough cutting with the 5- axis milling machine, the machining coordinates unification, and the selection of layer direction in turning. The onmachine measuring method based on stylus gauge is designed to analyze the shape deviation. The air bearing is used as the measuring staff and the laser interferometer sensor as the position sensor, whose repeatability accuracy is proved up to 10nm and the stable feature keeps well. With this method developed, the complex mirror with nanometric finish of 10.7nm in Ra and the form error within 1um are achieved.

  14. Intracranial aneurysms: evaluation in 200 patients with spiral CT angiography

    International Nuclear Information System (INIS)

    Young, N.; Kingston, R.J.; Markson, G.; Dorsch, N.W.C.; McMahon, J.

    2001-01-01

    The goal of this study was to assess the usefulness of spiral CT angiography (CTA) with three- dimensional reconstructions in defining intracranial aneurysms, particularly around the Circle of Willis. Two hundred consecutive patients with angiographic and/or surgical correlation were studied between 1993 and 1998, with CTA performed on a GE HiSpeed unit and Windows workstation. The following clinical situations were evaluated: conventional CT suspicion of an aneurysm; follow-up of treated aneurysm remnants or of untreated aneurysms; subarachnoid haemorrhage (SAH) and negative angiography; family or past aneurysm history; and for improved definition of aneurysm anatomy. Spiral CTA detected 140 of 144 aneurysms, and an overall sensitivity of 97%, including 30 of 32 aneurysms 3 mm or less in size. In 38 patients with SAH and negative angiography, CTA found six of the seven aneurysms finally diagnosed. There was no significant artefact in 17 of 23 patients (74%) with clips. The specificity of CTA was 86% with 8 false-positive cases. Spiral CTA is very useful in demonstrating intracranial aneurysms. (orig.)

  15. Three-dimensional spiral CT for neurosurgical planning

    International Nuclear Information System (INIS)

    Klein, H.M.; Bertalanffy, H.; Mayfrank, L.; Thron, A.; Guenther, R.W.; Gilsbach, J.M.

    1994-01-01

    We carried out 22 examinations to determine the value of three-dimensional (3D) volumetric CT (spiral CT) for planning neurosurgical procedures. All examinations were carried out on a of the first generation spiral CT. A tube model was used to investigate the influence of different parameter settings. Bolus injection of nonionic contrast medium was used when vessels or strongly enhancing tumours were to be delineated. 3D reconstructions were carried out using the integrated 3D software of the scanner. We found a table feed of 3 mm/s with a slice thickness of 2 mm and an increment of 1 mm to be suitable for most purposes. For larger regions of interest a table feed of 5 mm was the maximum which could be used without blurring of the 3D images. Particular advantages of 3D reconstructed spiral scanning were seen in the planning of approaches to the lower clivus, acquired or congenital bony abnormalities and when the relationship between vessels, tumour and bone was important. (orig.)

  16. 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.

  17. Magnetostrictive hypersound generation by spiral magnets in the vicinity of magnetic field induced phase transition

    Energy Technology Data Exchange (ETDEWEB)

    Bychkov, Igor V. [Chelyabinsk State University, 129 Br. Kashirinykh Str., Chelyabinsk 454001 (Russian Federation); South Ural State University (National Research University), 76 Lenin Prospekt, Chelyabinsk 454080 (Russian Federation); Kuzmin, Dmitry A., E-mail: kuzminda@csu.ru [Chelyabinsk State University, 129 Br. Kashirinykh Str., Chelyabinsk 454001 (Russian Federation); South Ural State University (National Research University), 76 Lenin Prospekt, Chelyabinsk 454080 (Russian Federation); Kamantsev, Alexander P.; Koledov, Victor V.; Shavrov, Vladimir G. [Kotelnikov Institute of Radio-engineering and Electronics of RAS, Mokhovaya Street 11-7, Moscow 125009 (Russian Federation)

    2016-11-01

    In present work we have investigated magnetostrictive ultrasound generation by spiral magnets in the vicinity of magnetic field induced phase transition from spiral to collinear state. We found that such magnets may generate transverse sound waves with the wavelength equal to the spiral period. We have examined two types of spiral magnetic structures: with inhomogeneous exchange and Dzyaloshinskii–Moriya interactions. Frequency of the waves from exchange-caused spiral magnetic structure may reach some THz, while in case of Dzyaloshinskii–Moriya interaction-caused spiral it may reach some GHz. These waves will be emitted like a sound pulses. Amplitude of the waves is strictly depends on the phase transition speed. Some aspects of microwaves to hypersound transformation by spiral magnets in the vicinity of phase transition have been investigated as well. Results of the work may be interesting for investigation of phase transition kinetics as well, as for various hypersound applications. - Highlights: • Magnetostrictive ultrasound generation by spiral magnets at phase transition (PT) is studied. • Spiral magnets during PT may generate transverse sound with wavelength equal to spiral period. • Amplitude of the sound is strictly depends on the phase transition speed. • Microwave-to-sound transformation in the vicinity of PT is investigated as well.

  18. Three-dimensional hard and soft tissue imaging of the human cochlea by scanning laser optical tomography (SLOT.

    Directory of Open Access Journals (Sweden)

    Nadine Tinne

    Full Text Available The present study focuses on the application of scanning laser optical tomography (SLOT for visualization of anatomical structures inside the human cochlea ex vivo. SLOT is a laser-based highly efficient microscopy technique which allows for tomographic imaging of the internal structure of transparent specimens. Thus, in the field of otology this technique is best convenient for an ex vivo study of the inner ear anatomy. For this purpose, the preparation before imaging comprises decalcification, dehydration as well as optical clearing of the cochlea samples in toto. Here, we demonstrate results of SLOT imaging visualizing hard and soft tissue structures with an optical resolution of down to 15 μm using extinction and autofluorescence as contrast mechanisms. Furthermore, the internal structure can be analyzed nondestructively and quantitatively in detail by sectioning of the three-dimensional datasets. The method of X-ray Micro Computed Tomography (μCT has been previously applied to explanted cochlea and is solely based on absorption contrast. An advantage of SLOT is that it uses visible light for image formation and thus provides a variety of contrast mechanisms known from other light microscopy techniques, such as fluorescence or scattering. We show that SLOT data is consistent with μCT anatomical data and provides additional information by using fluorescence. We demonstrate that SLOT is applicable for cochlea with metallic cochlear implants (CI that would lead to significant artifacts in μCT imaging. In conclusion, the present study demonstrates the capability of SLOT for resolution visualization of cleared human cochleae ex vivo using multiple contrast mechanisms and lays the foundation for a broad variety of additional studies.

  19. Diagnosis of pulmonary embolism with spiral and electron-beam CT; Diagnostik der Lungenembolie mit Spiral- und Elektronenstrahl-CT

    Energy Technology Data Exchange (ETDEWEB)

    Schoepf, U.J.; Bruening, R.D.; Becker, C.R.; Konschitzky, H.; Muehling, O.; Staebler, A.; Helmberger, T.; Holzknecht, N.; Reiser, M.F. [Muenchen Univ. (Germany). Inst. fuer Radiologische Diagnostik; Knez, A.; Haberl, R. [Muenchen Univ. (Germany). Medizinische Klinik 1

    1998-12-01

    Purpose: To compare spiral (SCT) and electron-beam CT (EBT) for the diagnosis of pulmonary embolism (PE). Materials and methods: From June 1997 to June 1998 188 patients with suspected acute or chronic thrombembolism of the pulmonary arteries were examined. A total of 108 patients were scanned using SCT and 80 patients using EBT. On each scanner two different scan protocols were evaluated. Conclusions: Advanced CT scanning techniques allow the highly accurate diagnosis of central and peripheral PE. Other potentially life-threatening underlying diseases are also readily recognized. (orig./AJ) [Deutsch] Fragestellung: Spiral-CT (SCT) und Elektronenstrahlcomputertomographie (EBT) sollten hinsichtlich ihrer Eignung fuer die Diagnostik der Lungenembolie (LE) verglichen werden. Methode: Von Juni 1997 bis Juni 1998 wurden 188 Patienten mit Verdacht auf akute oder chronische thrombembolische Veraenderungen der Lungenarterien untersucht. Die CT-Diagnostik erfolgte dabei bei 108 Patienten mit Spiral-CT und bei 80 Patienten mit EBT. Schlussfolgerungen: Moderne CT-Scan-Verfahren erlauben mit hoher Genauigkeit die Diagnose der zentralen und peripheren Lungenembolie. Die EBT bietet Vorteile in der Darstellung herznaher peripherer Lungenarterien. Andere lebendsbedrohliche Ursachen fuer die Beschwerden des Patienten werden mit der CT sicher erkannt. (orig./AJ)

  20. Enhancement of acousto-optical coupling in two-dimensional air-slot phoxonic crystal cavities by utilizing surface acoustic waves

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Tian-Xue [Institute of Engineering Mechanics, Beijing Jiaotong University, Beijing 100044 (China); Wang, Yue-Sheng, E-mail: yswang@bjtu.edu.cn [Institute of Engineering Mechanics, Beijing Jiaotong University, Beijing 100044 (China); Zhang, Chuanzeng [Department of Civil Engineering, University of Siegen, D-57068 Siegen (Germany)

    2017-01-30

    A phoxonic crystal is a periodically patterned material that can simultaneously localize optical and acoustic modes. The acousto-optical coupling in two-dimensional air-slot phoxonic crystal cavities is investigated numerically. The photons can be well confined in the slot owing to the large electric field discontinuity at the air/dielectric interfaces. Besides, the surface acoustic modes lead to the localization of the phonons near the air-slot. The high overlap of the photonic and phononic cavity modes near the slot results in a significant enhancement of the moving interface effect, and thus strengthens the total acousto-optical interaction. The results of two cavities with different slot widths show that the coupling strength is dependent on the slot width. It is expected to achieve a strong acousto-optical/optomechanical coupling in air-slot phoxonic crystal structures by utilizing surface acoustic modes. - Highlights: • Two-dimensional air-slot phoxonic crystal cavities which can confine simultaneously optical and acoustic waves are proposed. • The acoustic and optical waves are highly confined near/in the air-slot. • The high overlap of the photonic and phononic cavity modes significantly enhances the moving interface effect. • Different factors which affect the acousto-optical coupling are discussed.

  1. Naming polyhedra by general face-spirals - theory and applications to fullerenes and other polyhedral molecules

    DEFF Research Database (Denmark)

    Wirz, Lukas; Schwerdtfeger, Peter; Avery, James Emil

    2018-01-01

    We present a general face-spiral algorithm for cubic polyhedral graphs (including fullerenes and fulleroids), and extend it to the full class of all polyhedral graphs by way of the leapfrog transform. This yields compact canonical representations of polyhedra with a simple and intuitive geometrical...... be found together with the canonical general spiral at negligible cost. The algorithm is fully compatible with the classical spiral algorithm developed by Manolopoulos for fullerenes, i. e., classical spirals are accepted as input, and spiralable graphs lead to identical output. We prove that the algorithm...... is correct and complete. The worst case runtime complexity is for general N-vertex polyhedral graphs, with J the sum of all jump lengths. When the number of faces of any particular size is bounded by a constant, such as the case for fullerenes, this reduces to . We have calculated canonical general spirals...

  2. Near monochromatic X-rays for digital slot-scan mammography: initial findings

    International Nuclear Information System (INIS)

    Diekmann, Felix; Diekmann, S.; Richter, K.; Bick, U.; Fischer, T.; Hamm, B.; Lawaczeck, R.; Press, W.R.; Schoen, K.; Weinmann, H.J.; Arkadiev, V.; Bjeoumikhov, A.; Langhoff, N.; Rabe, J.; Roth, P.; Tilgner, J.; Wedell, R.; Krumrey, M.; Linke, U.; Ulm, G.

    2004-01-01

    X-ray spectra are composed of a broad bremsspectrum and anode-characteristic emission lines. In mammography typically molybdenum (Mo), rhodium (Rh) or tungsten (W) anodes are used in combination with Mo, Rh or aluminium filters. Only the photons with energies between 17 and 22 keV of the resulting spectrum are suitable for the soft tissue imaging needed for mammography. The aim of this article is to present first results obtained with a monochromator module mounted at the exit of the X-ray tube of a conventional clinical mammography unit. The experimental setup consists of a Siemens Mammomat 300, an X-ray monochromator module and a linear array detector for image acquisition. The technique is similar to the slot-scan technique known from digital mammography. The experimental machine allows to obtain images both with polychromatic and monochromatic X-rays. Initial evaluation of the system was performed by examination of a contrast-detail phantom (CD-MAM-phantom, Nijmegen, The Netherlands). Images done with the new monochromatic technique were compared to images of the phantom done with polychromatic spectra, with film-screen mammography as well as with digital mammography. The new technique with monochromatic slot-scan mammography resulted in correct identification of 93% of the phantom. Digital slot-scan mammography with polychromatic beam resulted in correct identification of 87%, digital full-field mammography in 83% and conventional film-screen mammography in 70% of the phantom. The results suggest that monochromatization has a potential for improving image quality or decreasing dose in X-ray mammography. (orig.)

  3. Slot Nozzle Effects for Reduced Sonic Boom on a Generic Supersonic Wing Section

    Science.gov (United States)

    Caster, Raymond S.

    2010-01-01

    NASA has conducted research programs to reduce or eliminate the operational restrictions of supersonic aircraft over populated areas. Restrictions are due to the disturbance from the sonic boom, caused by the coalescence of shock waves formed off the aircraft. Results from two-dimensional computational fluid dynamic (CFD) analyses (performed on a baseline Mach 2.0 nozzle in a simulated Mach 2.2 flow) indicate that over-expanded and under-expanded operation of the nozzle has an effect on the N-wave boom signature. Analyses demonstrate the feasibility of reducing the magnitude of the sonic boom N-wave by controlling the nozzle plume interaction with the nozzle boat tail shock structure. This work was extended to study the impact of integrating a high aspect ratio exhaust nozzle or long slot nozzle on the trailing edge of a supersonic wing. The nozzle is operated in a highly under-expanded condition, creating a large exhaust plume and a shock at the trailing edge of the wing. This shock interacts with and suppresses the expansion wave caused by the wing, a major contributor to the sonic boom signature. The goal was to reduce the near field pressures caused by the expansion using a slot nozzle located at the wing trailing edge. Results from CFD analysis on a simulated wing cross-section and a slot nozzle indicate potential reductions in sonic boom signature compared to a baseline wing with no propulsion or trailing edge exhaust. Future studies could investigate if this effect could be useful on a supersonic aircraft for main propulsion, auxiliary propulsion, or flow control.

  4. Courses timetabling problem by minimizing the number of less preferable time slots

    Science.gov (United States)

    Oktavia, M.; Aman, A.; Bakhtiar, T.

    2017-01-01

    In an organization with large number of resources, timetabling is one of the most important factors of management strategy and the one that is most prone to errors or issues. Timetabling the perfect organization plan is quite a task, thus the aid of operations research or management strategy approaches is obligation. Timetabling in educational institutions can roughly be categorized into school timetabling, course timetabling, and examination timetabling, which differ from each other by their entities involved such as the type of events, the kind of institution, and the type and the relative influence of constraints. Education timetabling problem is generally a kind of complex combinatorial problem consisting of NP-complete sub-problems. It is required that the requested timetable fulfills a set of hard and soft constraints of various types. In this paper we consider a courses timetabling problem at university whose objective is to minimize the number of less preferable time slots. We mean by less preferable time slots are those devoted in early morning (07.00 - 07.50 AM) or those in the late afternoon (17.00 - 17.50 AM) that in fact beyond the working hour, those scheduled during the lunch break (12.00 - 12.50 AM), those scheduled in Wednesday 10.00 - 11.50 AM that coincides with Department Meeting, and those in Saturday which should be in fact devoted for day-off. In some cases, timetable with a number of activities scheduled in abovementioned time slots are commonly encountered. The courses timetabling for the Educational Program of General Competence (PPKU) students at odd semester at Bogor Agricultural University (IPB) has been modelled in the framework of the integer linear programming. We solved the optimization problem heuristically by categorizing all the groups into seven clusters.

  5. Using Drainage Slots in Permeable Paving Blocks to Delay the Effects of Clogging: Proof of Concept Study

    Directory of Open Access Journals (Sweden)

    Terry Lucke

    2014-09-01

    Full Text Available Permeable interlocking concrete pavements (PICP are specifically designed to remove sediment and other pollutants from stormwater runoff. Over time, this can lead to clogging of the PICP system. Previous research has shown that much of the clogging occurs on the bedding aggregate directly below the paving joints, while the remainder of the aggregate is unaffected. This paper describes a proof of concept study to delay the effects of clogging by making more efficient use of the bedding aggregate used in PICP systems. Lateral drainage slots were cut into the underside of PICP blocks to allow sediment-laden stormwater to access, and be filtered by, a greater surface area of bedding aggregate. Eight different slot designs were trialed in the study to determine which of the slot designs made the most efficient use of the bedding aggregate to filter the sediment from the stormwater. The study results demonstrated that the eight drainage slot designs deposited between 25% and 366% more sediment (by weight beneath the pavers than the control pavement. The results of the study suggest that PICP systems with drainage slots cast into their bases would take much longer to clog than unmodified pavers, thereby proving the concept of this study.

  6. Design and investigations of a microstrip fed open V-shape slot antenna for wideband dual slant polarization

    Directory of Open Access Journals (Sweden)

    R.V.S. Ram Krishna

    2015-12-01

    Full Text Available A dual slant polarized slot antenna is proposed. The antenna is printed on the two sides of a single substrate and has two microstrip feed lines to excite a V-shaped slot formed by the merging of two tilted rectangular step shaped slots. Stepping of the slot sections as well as the feed line improves the impedance matching. A narrow rectangular metallic stub is introduced at the junction of the slot arms to improve the decoupling between the ports. The antenna polarization is +450/−450 with respect to horizontal under alternate excitation and this dual slant polarized nature is demonstrated through aperture electric field plots and far field radiation patterns. The measured return loss bandwidth (S11 < −10 dB of the antenna is from 2.3 GHz and extends beyond 12 GHz while the measured isolation bandwidth (S21 < −20 dB is from 5 GHz onwards. The time domain characterization of the antenna is also done by calculating the fidelity factor. For evaluating the diversity performance, the envelope correlation coefficients are calculated from the simulated and measured S-parameters. The correlation coefficients are well below the acceptable values. With a peak gain varying between 3 and 5 dBi, the antenna is expected to be useful for wideband dual slant polarized applications.

  7. Numerical exploration of non-axisymmetric divertor closure in the small angle slot (SAS) divertor at DIII-D

    Science.gov (United States)

    Frerichs, Heinke; Schmitz, Oliver; Covele, Brent; Guo, Houyang; Hill, David; Feng, Yuhe

    2017-10-01

    In the Small Angle Slot (SAS) divertor in DIII-D, the combination of misaligned slot structure and non-axisymmetric perturbations to the magnetic field causes the strike point to vary radially along the divertor slot and even leave it at some toroidal locations. This effect essentially introduces an opening in the divertor slot from where recycling neutrals can easily escape, and thereby degrade performance of the slot divertor. This effect has been approximated by a finite gap in the divertor baffle. Simulations with EMC3-EIRENE show that a toroidally localized loss of divertor closure can result in non-axisymmetric divertor densities and temperatures. This introduces a density window of 10-15% on top of the nominal threshold separatrix density during which a non-axisymmetric onset of local detachment occurs, initially leaving the gap and up to 60 deg beyond that still attached. Conversely, the impact of such toroidally localized divertor perturbations on the toroidal symmetry of midplane separatrix conditions is small. This work has been funded by the U.S. Department of Energy under Early Career Award Grant DE-SC0013911, and Grant DE-FC02-04ER54698.

  8. Resistive wall impedance of the LHC beam screen without slots calculated by boundary element method

    CERN Document Server

    Tsutsui, H

    2002-01-01

    In order to calculate the resistive wall impedance of the LHC beam screen without slots, the Boundary Element Method (BEM) is used. The result at 1 GHz is Re(ZL/L) = 6.689×10−3 Ω/m, Re(Zx/L) = 1.251 Ω/m2, Re(Zy/L) = 1.776 Ω/m2, andRe(2Z0,2 cos/kL) = −0.525 Ω/m2, assuming σ = 5.8 × 109 /Ωm.

  9. Cogging Torque Reduction in Brushless DC Motors Using Slot-Opening Shift

    Directory of Open Access Journals (Sweden)

    SAIED, S. A.

    2009-02-01

    Full Text Available In this paper, two new methods for the stator skew are introduced. In contrary with the conventional stator skew, this paper is concentrate on the slot-opening skew. The simula-tion result by finite element shows a considerable reduction in the cogging torque of the motors, the new methods are applied to. Moreover the simulations justify that the back-EMF shape remains trapezoidal for various skew angles in contrary with that in the conventional skew, this fact makes the method highly applicable in BLDC motors.

  10. The effect of a magnetic field on heat transfer in a slotted channel

    International Nuclear Information System (INIS)

    Evtushenko, I.A.; Hua, T.Q.; Kirillov, I.R.; Reed, Claude B.; Sidorenkov, S.S.

    1995-01-01

    The results of numerical and experimental studies of liquid metal heat transfer in slotted channels in a transverse magnetic field are presented. Test results showed an improvement in heat transfer in a straight channel at low and moderate interaction parameter N. The Nusselt number at small N (around 120) was up to twofold higher than in turbulent flow without a magnetic field, the Peclet number being equal. This effect of heat transfer enhancement is caused by the generation and development of large-scale velocity fluctuations close to the heated wall area. Qualitative and quantitative correlations between heat transfer and velocity fluctuation characteristics are presented. (orig.)

  11. Fast printing and in situ morphology observation of organic photovoltaics using slot-die coating.

    Science.gov (United States)

    Liu, Feng; Ferdous, Sunzida; Schaible, Eric; Hexemer, Alexander; Church, Matthew; Ding, Xiaodong; Wang, Cheng; Russell, Thomas P

    2015-02-04

    The mini-slot-die coater offers a simple, convenient, materials-efficient route to print bulk-heterojunction (BHJ) organic photovoltaics (OPVs) that show efficiencies similar to spin-coating. Grazing-incidence X-ray diffraction (GIXD) and GI small-angle X-ray scattering (GISAXS) methods are used in real time to characterize the active-layer formation during printing. A polymer-aggregation-phase-separation-crystallization mechanism for the evolution of the morphology describes the observations. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Modelling of flow in the unloading slot of the control valve

    Science.gov (United States)

    Mrózek, Lukáš; Tajč, Ladislav

    2017-09-01

    The flow in the unloading system of the control valve is modelled. Values of the flow coefficient for various slot widths and openings are evaluated. The changes of pressure in the spaces of the valve are recorded when the performance of the turbine is regulated and its impacts on the level of the stabilizing power at the given setting of the cone lift are evaluated. The results from experiments on the air model of the system are compared with the pressures measured on the model of the valve. The operational characteristics of the experimental steam turbine is considered.

  13. Convective Flow of a Colloidal Suspension in a Vertical Slot Heated from Side Wall

    Science.gov (United States)

    Cherepanov, I. N.; Smorodin, B. L.

    2018-02-01

    Convective flows and the transport of nanoparticles are numerically investigated in the vertical slot filled with a colloidal suspension and heated from the side. The thermodiffusion and gravitational sedimentation of the nanoparticles are taken into account. Two different regimes of laminar flow are found. The intensity of the first regime is much lower than in molecular liquids (the magnitudes of the convective and diffusion fluxes have the same order). The second regime is more intensive. The transitions between these two regimes are investigated. It is shown that intensive convective flow completely mixes the colloidal suspension to a homogeneous state as a result of the long transient process.

  14. Drift and breakup of spiral waves in reaction–diffusion–mechanics systems

    OpenAIRE

    Panfilov, A. V.; Keldermann, R. H.; Nash, M. P.

    2007-01-01

    Rotating spiral waves organize excitation in various biological, physical, and chemical systems. They underpin a variety of important phenomena, such as cardiac arrhythmias, morphogenesis processes, and spatial patterns in chemical reactions. Important insights into spiral wave dynamics have been obtained from theoretical studies of the reaction–diffusion (RD) partial differential equations. However, most of these studies have ignored the fact that spiral wave rotation is often accompanied by...

  15. Pulmonary embolism: spiral CT evaluation; Embolie pulmonaire: apport de la tomodensitometrie helicoidale

    Energy Technology Data Exchange (ETDEWEB)

    Senac, J.P.; Vernhet, H.; Bousquet, C.; Giron, J.; Pieuchot, P.; Durand, G.; Benezet, O.; Aubas, P. [Centre Hospitalier Universitaire, 34 - Montpellier (France)

    1995-06-01

    Purpose: Spiral computed tomography was compared retrospectively with digital substraction pulmonary angiography (PA) in 45 patients suspected of having acute or chronic pulmonary embolism. Materials and method : 45 patients in whom the presence of acute or chronic pulmonary embolism was suspected underwent examination by spiral CT and PA. Diagnosis of pulmonary embolism was based on the direct visualization of intraluminal clots. The study of the agreement between the two methods was based on the Kappa test. In 35 cases, pulmonary emboli were proved. Acute pulmonary emboli were present in 28 cases and chronic in 7 cases. Results: Spiral computed tomography represents an excellent way to detect acute pulmonary embolism. In the chronic form, spiral CT is better than PA to detect intraluminal clots. However, Spiral CT can fail to detect small emboli in the peripheral arterial bed. In the 10 patients without pulmonary embolism, the spiral CT proved diagnosis pulmonary oedema (n=3), lymphangi-carcinoma (n=4), pleural effusion (n=3). Conclusion: This study suggest that the spiral CT examination is accurate for diagnosis of pulmonary embolism specifically in case of suspected important embolism. The advantages of spiral CT are multiple (non invasive, wide diagnosis spectrum). However, may be a limitation to is use is insufficient distal thrombi detection. This eventuality (5 to 10% in the Pioped study) justify the practice of pulmonary angiography. Spiral CT improvements should reduce this insufficiency in the next future. (Authors). 16 refs., 4 figs., 3 tabs.

  16. Magnetic field sensor based on fiber Bragg grating with a spiral microgroove ablated by femtosecond laser.

    Science.gov (United States)

    Dai, Yutang; Yang, Minghong; Xu, Gang; Yuan, Yinquan

    2013-07-15

    A novel magnetic field sensor based on Terfenol-D coated fiber Bragg grating with spiral microstructure was proposed and demonstrated. Through a specially-designed holder, the spiral microstructure was ablated into the fiber Bragg grating (FBG) cladding by femtosecond laser. Due to the spiral microstructure, the sensitivity of FBG coated with magnetostrictive film was enhanced greatly. When the spiral pitch is 50 μm and microgroove depth is 13.5 μm, the sensitivity of the magnetic field sensor is roughly 5 times higher than that of non-microstructured standard FBG. The response to magnetic field is reversible, and could be applicable for magnetic field detection.

  17. Geometric Offsets Across Spiral Arms in M51: Nature of Gas and Star Formation Tracers

    OpenAIRE

    Louie, M.; Koda, J.; Egusa, F.

    2013-01-01

    We report measurements of geometric offsets between gas spiral arms and associated star forming regions in the grand-design spiral galaxy M51. These offsets are a suggested measure of the star formation timescale after the compression of gas at spiral arm entry. A surprising discrepancy, by an order of magnitude, has been reported in recent offset measurements in nearby spiral galaxies. Measurements using CO and H-alpha emission find large and ordered offsets in M51. On the contrary, small or...

  18. A novel measuring method for arbitrary optical vortex by three spiral spectra

    Energy Technology Data Exchange (ETDEWEB)

    Ni, Bo [School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Guo, Lana [School of Electronics and Information, Guangdong Polytechnic Normal University, Guangzhou 510665 (China); Yue, Chengfeng [School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Tang, Zhilie, E-mail: tangzhl@scnu.edu.cn [School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China)

    2017-02-26

    In this letter, the topological charge of non-integer vortices determined by three arbitrary spiral spectra is theoretically demonstrated for the first time. Based on the conclusion, a novel method to measure non-integer vortices is presented. This method is applicable not only to arbitrary non-integer vortex but also to arbitrary integer vortex. - Highlights: • Different non-integer vortices cannot have three spiral spectra is demonstrated. • Relationship between the non-integer topological charge and the spiral spectra is presented. • Topological charge of non-integer vortices can be determined by three arbitrary spiral spectra.

  19. CFD simulation of flow through single and multi vane spiral pump for low pressure application using moving node unsteady computation

    International Nuclear Information System (INIS)

    Banerjee, I.; Mahendra, A.K.; Chandresh, B.G.; Srikanthan, M.R.; Bera, T.K.

    2010-01-01

    A spiral pump uses two interleaved spirals (it can be involutes of a circle, involutes of a square, hybrid wraps, Archimedean spiral, logarithmic spirals and so on). Interleaved spiral orbits eccentrically without rotation around a fixed scroll, thereby trapping and compressing pockets of fluids between the spirals. Another method of providing the compression motion is by virtue of co-rotating the spirals synchronously with an offset in centers of rotation thereby providing relative motion similar to orbiting. Recently spiral pumps for low-pressure application have become popular. Since spiral pumps contain gas volumes, whose shapes and size change continuously, the flow fields inside the pumps is time dependent. The unsteadiness controls the mechanisms responsible for the behavior of the spiral pump components. To improve the spiral pump design for better performance as per our process requirement and reliability, information is required to understand the detailed physics of the unsteady flows inside the spiral pumps. The unsteady flows in a pump are studied numerically. The system simulated includes one side gap between fixed and moving spirals as the other side lies just in the reverse symmetry of the one side. Heavy molecular weight, condensable gas is used as the moving fluid. The mesh free Least Square Kinetic Upwind Method (LSKUM) for moving node is applied for numerical analysis of wobbling spiral. Nodes and boundaries change their positions, for every real time step hence at every iteration nodes take new coordinates. Our work consists of identifying various spiral dimensions and geometry, geometric modeling of suction process, identifying the eccentric orbiting motion of the moving spiral, formation of variable velocity moving nodes. Flow analysis of the spiral pump is done with a view to design and develop new pump as per our requirement. Experimental data from an existing spiral pump is used to carryout validation of the code. (author)

  20. Virtual gastroscopy using spiral CT in gastric lesions

    International Nuclear Information System (INIS)

    Shin, Sang Soo; Kang, Heoung Keun; Jeong, Yong Yeon; Yoon, Man Won; Song, Sang Gook; Jeong, Gwang Woo

    1998-01-01

    To compare virtual gastroscopy using spiral CT with conventional endoscopy for the detection and evaluation of gastric lesions. During a previous six-month period, 30 patients with pathologically-proven gastric lesions underwent conventional endoscopy and virtual gastroscopy using spiral CT. There were 18 cases of advanced gastric carcinoma, eight benign ulcers, and four submucosal tumors(two leiomyomas, two lymphomas). Source images of virtual gastroscopy were three-dim-ensionally reconstructed within an Advantage Windows Workstation and virtual gastroscopic images were obtained using Navigator Software. On analysis, images were graded according to their quality(excellent, good, poor). Virtual gastroscopic images were interpreted by two radiologists blinded to conventional endoscopic findings, and were subsequently compared with endoscopic findings in terms of detectability and findings. In the cases of advanced gastric carcinoma, lesions were classified according to Borrmann's system. For virtual gastroscopy, overall image quality was excellent in 21 cases(70%), good in five(17%), and poor in four(13%). Lesions were detected in 25 cases(83%). Among the 18 advanced gastric carcinomas, virtual gastroscopy image quality was excellent in 14 cases(78%), good in two(11%), and poor in two(11%). Lesions were detected in 16 cases(89%). Two Borrmann type IV cases were not detected. Among the eight benign ulcers, virtual gastroscopy image quality was excellent in three cases(38%), good in three(38%), and poor in two(25%). The detection of lesion was possible in five cases(63%). In all submucosal tumors, virtual gastroscopy image quality was excellent. Lesions were detected in all cases. Virtual gastroscopy using spiral CT is safe and noninvasive, and for the evaluation of gastric lesions may be complementary to axial CT. It successfully detects gastric lesions, and in depicting the pattern of gastric folds its image quality is excellent.=20