WorldWideScience

Sample records for helical deflecting system

  1. A blade deflection monitoring system

    DEFF Research Database (Denmark)

    2017-01-01

    A wind turbine blade comprising a system for monitoring the deflection of a wind turbine blade is described. The system comprises a wireless range-measurement system, having at least one wireless communication device located towards the root end of the blade and at least one wireless communication...

  2. Deflection system for charged-particle beam

    Energy Technology Data Exchange (ETDEWEB)

    Bates, T

    1982-01-13

    A system is described for achromatically deflecting a beam of charged particles without producing net divergence of the beam comprising three successive magnetic deflection means which deflect the beam alternately in opposite directions; the first and second deflect by angles of less than 50/sup 0/ and the third by an angle of at least 90/sup 0/. Particles with different respective energies are transversely spaced as they enter the third deflection means, but emerge completely superimposed in both position and direction and may be brought to a focus in each of two mutually perpendicular planes, a short distance thereafter. Such a system may be particularly compact, especially in the direction in which the beam leaves the system. It is suitable for deflecting a beam of electrons from a linear accelerator so producing a vertical beam of electron (or with an X-ray target, of X-rays) which can be rotated about a horizontal patient for radiation therapy.

  3. Deflection

    Directory of Open Access Journals (Sweden)

    M. Hatami

    2014-08-01

    Full Text Available In this paper, deflection prediction of a cantilever beam subjected to static co-planar loading is investigated using the Differential Transformation Method (DTM and the Homotopy Perturbation Method (HPM. An axial compressive force, FA, and a transverse force, QA, are applied to the beam. It is considered that these forces are follower forces, i.e., they will rotate with the end section of the beam during the deformation, and they will remain tangential and perpendicular at all times, respectively. Comparison between DTM and HPM through numerical results demonstrates that DTM can be an exact and highly efficient procedure for solving these kind of problems. Also the influence of the effect of some parameters appeared in mathematical formulations such as area moment of inertia (I, Young’s modulus (E, transverse force (QA and compressive force (FA on slope variation are investigated in the present study. The results show that slope parameter as well as compressive force increases. By increasing the QA, slope parameter is increased significantly. By increasing the E, due to stiffness of the material, slope variation is decreased. It is evident that when the size of the beam section increases, the area moment of inertia (I will be increased and so the slope variation will be decreased.

  4. Structural analysis of compression helical spring used in suspension system

    Science.gov (United States)

    Jain, Akshat; Misra, Sheelam; Jindal, Arun; Lakhian, Prateek

    2017-07-01

    The main aim of this work has to develop a helical spring for shock absorber used in suspension system which is designed to reduce shock impulse and liberate kinetic energy. In a vehicle, it increases comfort by decreasing amplitude of disturbances and it improves ride quality by absorbing and dissipating energy. When a vehicle is in motion on a road and strikes a bump, spring comes into action quickly. After compression, spring will attempt to come to its equilibrium state which is on level road. Helical springs can be made lighter with more strength by reducing number of coils and increasing the area. In this research work, a helical spring is modeled and analyzed to substitute the existing steel spring which is used in suspension. By using different materials, stress and deflection of helical spring can be varied. Comparability between existing spring and newly replaced spring is used to verify the results. For finding detailed stress distribution, finite element analysis is used to find stresses and deflection in both the helical springs. Finite element analysis is a method which is used to find proximate solutions of a physical problem defined in a finite domain. In this research work, modeling of spring is accomplished using Solid Works and analysis on Ansys.

  5. A Bridge Deflection Monitoring System Based on CCD

    Directory of Open Access Journals (Sweden)

    Baohua Shan

    2016-01-01

    Full Text Available For long-term monitoring of the midspan deflection of Songjiazhuang cloverleaf junction on 309 national roads in Zibo city, this paper proposes Zhang’s calibration-based DIC deflection monitoring method. CCD cameras are used to track the change of targets’ position, Zhang’s calibration algorithm is introduced to acquire the intrinsic and extrinsic parameters of CCD cameras, and the DIC method is combined with Zhang’s calibration algorithm to measure bridge deflection. The comparative test between Zhang’s calibration and scale calibration is conducted in lab, and experimental results indicate that the proposed method has higher precision. According to the deflection monitoring scheme, the deflection monitoring software for Songjiazhuang cloverleaf junction is developed by MATLAB, and a 4-channel CCD deflection monitoring system for Songjiazhuang cloverleaf junction is integrated in this paper. This deflection monitoring system includes functions such as image preview, simultaneous collection, camera calibration, deflection display, and data storage. In situ deflection curves show a consistent trend; this suggests that the proposed method is reliable and is suitable for the long-term monitoring of bridge deflection.

  6. A proton microbeam deflection system to scan target surfaces

    International Nuclear Information System (INIS)

    Heck, D.

    1978-12-01

    A system to deflect the proton beam within the Karlsruhe microbeam setup is described. The deflection is achieved whithin a transverse electrical field generated between parallel electrodes. Their tension is controlled by a pattern generator, thus enabling areal and line scans with a variable number of scan points at variable scan speed. The application is demonstrated at two different examples. (orig.) [de

  7. MHD stability analysis of helical system plasmas

    International Nuclear Information System (INIS)

    Nakamura, Yuji

    2000-01-01

    Several topics of the MHD stability studies in helical system plasmas are reviewed with respect to the linear and ideal modes mainly. Difference of the method of the MHD stability analysis in helical system plasmas from that in tokamak plasmas is emphasized. Lack of the cyclic (symmetric) coordinate makes an analysis more difficult. Recent topic about TAE modes in a helical system is also described briefly. (author)

  8. Helical system. History and current state of helical research

    International Nuclear Information System (INIS)

    Yokoyama, Masayuki

    2017-01-01

    This paper described the following: (1) history of nuclear fusion research of Japan's original heliotron method, (2) worldwide development of nuclear fusion research based on helical system such as stellarator, and (3) worldwide meaning of large helical device (LHD) aiming to demonstrate the steady-state performance of heliotron type in the parameter area extrapolable to the core plasma, and research results of LHD. LHD demonstrated that the helical system is excellent in steady operation performance at the world's most advanced level. In an experiment using deuterium gas in 2017, LHD achieved to reach 120 million degrees of ion temperature, which is one index of nuclear fusion condition, demonstrated the realization of high-performance plasma capable of extrapolating to future nuclear fusion reactors, and established the foundation for full-scale research toward the realization of nuclear fusion reactor. Besides experimental research, this paper also described the helical-type stationary nuclear fusion prototype reactor, FFHR-d1, which was based on progress of large-scale simulation at the world's most advanced level. A large-scale superconducting stellarator experimental device, W7-X, with the same scale as LHD, started experiment in December 2015, whose current state is also touched on here. (A.O.)

  9. Double deflection system for an electron beam device

    International Nuclear Information System (INIS)

    Parker, N.W.; Crewe, A.V.

    1978-01-01

    A double deflection scanning system for electron beam instruments is provided embodying a means of correcting isotropic coma, and anisotropic coma aberrations induced by the magnetic lens of such an instrument. The scanning system deflects the beam prior to entry into the magnetic lens from the normal on-axis intersection of the beam with the lens according to predetermined formulas and thereby reduces the aberrations

  10. Gravitational light deflection in the Solar System

    International Nuclear Information System (INIS)

    Cowling, S.A.

    1984-01-01

    The problems of defining the bending of a light path in general stationary space-times are discussed. It is shown how in situations of axial symmetry the use of 'triangulation lines' leads to a coordinate invariant definition of the bending angle between arbitrary points on a light path. An exact expression is derived for the bending angle in a static, spherically symmetric space-time of arbitrarily strong curvature. This formulation is used to calculate, to second PPN order, the apparent positional shift which is measured when observing, for example, an asteroid or a spacecraft situated close to superior conjunction with the Sun. The possibilities of measuring light deflection effects using modern observational facilities are considered. (author)

  11. A deflection monitoring system for a wind turbine blade

    DEFF Research Database (Denmark)

    2017-01-01

    A wind turbine blade comprising a system for monitoring the deflection of a wind turbine blade is described. The system comprises a wireless range-measurement system, having at least one wireless communication device located towards the root end of the blade and at least one wireless communication...

  12. Dynamics of zonal flows in helical systems.

    Science.gov (United States)

    Sugama, H; Watanabe, T-H

    2005-03-25

    A theory for describing collisionless long-time behavior of zonal flows in helical systems is presented and its validity is verified by gyrokinetic-Vlasov simulation. It is shown that, under the influence of particles trapped in helical ripples, the response of zonal flows to a given source becomes weaker for lower radial wave numbers and deeper helical ripples while a high-level zonal-flow response, which is not affected by helical-ripple-trapped particles, can be maintained for a longer time by reducing their bounce-averaged radial drift velocity. This implies a possibility that helical configurations optimized for reducing neoclassical ripple transport can simultaneously enhance zonal flows which lower anomalous transport.

  13. Transport barrier in Helical system

    International Nuclear Information System (INIS)

    Ida, Katsumi

    1998-01-01

    Experiments on the transport barrier in Helical plasmas are reviewed. There are two mechanisms of transport improvement, that results in the formation of the transport barrier. One is the improvement of neoclassical transport by reducing the ripple loss with radial electric field, which exist only in helical plasma. The other is the improvement of anomalous transport due to the suppression of fluctuations associated with a radial electric field shear both in tokamak and helical plasma. The formation of the transport barrier can be triggered by the radial electric field shear associated with the transition of the radial electric field (L/H transition or ion-electron root transition) or the peaked density or the optimization of magnetic field shear. The mechanisms of transport barrier formation are also discussed. (author). 60 refs

  14. Adaptive radiotherapy using helical tomotherapy system

    International Nuclear Information System (INIS)

    Jeswani, Sam; Ruchala, Kenneth; Olivera, Gustavo; Mackie, T.R.

    2008-01-01

    As commonly known in the field, adaptive radiation therapy (ART) is the use of feedback to modify a radiotherapy treatment. There are numerous ways in which this feedback can be received and used, and this presentation will discuss some of the implementations of ART being investigated with a helical TomoTherapy system

  15. Vacuum systems for the ILC helical undulator

    CERN Document Server

    Malyshev, O B; Clarke, J A; Bailey, I R; Dainton, J B; Malysheva, L I; Barber, D P; Cooke, P; Baynham, E; Bradshaw, T; Brummitt, A; Carr, S; Ivanyushenkov, Y; Rochford, J; Moortgat-Pick, G A

    2007-01-01

    The International Linear Collider (ILC) positron source uses a helical undulator to generate polarized photons of ∼10MeV∼10MeV at the first harmonic. Unlike many undulators used in synchrotron radiation sources, the ILC helical undulator vacuum chamber will be bombarded by photons, generated by the undulator, with energies mostly below that of the first harmonic. Achieving the vacuum specification of ∼100nTorr∼100nTorr in a narrow chamber of 4–6mm4–6mm inner diameter, with a long length of 100–200m100–200m, makes the design of the vacuum system challenging. This article describes the vacuum specifications and calculations of the flux and energy of photons irradiating the undulator vacuum chamber and considers possible vacuum system design solutions for two cases: cryogenic and room temperature.

  16. Ion temperature gradient modes in toroidal helical systems

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, T. [Graduate University for Advanced Studies, Toki, Gifu (Japan); Sugama, H.; Kanno, R.; Okamoto, M.

    2000-04-01

    Linear properties of ion temperature gradient (ITG) modes in helical systems are studied. The real frequency, growth rate, and eigenfunction are obtained for both stable and unstable cases by solving a kinetic integral equation with proper analytic continuation performed in the complex frequency plane. Based on the model magnetic configuration for toroidal helical systems like the Large Helical Device (LHD), dependences of the ITG mode properties on various plasma equilibrium parameters are investigated. Particularly, relative effects of {nabla}B-curvature drifts driven by the toroidicity and by the helical ripples are examined in order to compare the ITG modes in helical systems with those in tokamaks. (author)

  17. Ion temperature gradient modes in toroidal helical systems

    International Nuclear Information System (INIS)

    Kuroda, T.; Sugama, H.; Kanno, R.; Okamoto, M.

    2000-04-01

    Linear properties of ion temperature gradient (ITG) modes in helical systems are studied. The real frequency, growth rate, and eigenfunction are obtained for both stable and unstable cases by solving a kinetic integral equation with proper analytic continuation performed in the complex frequency plane. Based on the model magnetic configuration for toroidal helical systems like the Large Helical Device (LHD), dependences of the ITG mode properties on various plasma equilibrium parameters are investigated. Particularly, relative effects of ∇B-curvature drifts driven by the toroidicity and by the helical ripples are examined in order to compare the ITG modes in helical systems with those in tokamaks. (author)

  18. Perspectives on confinement in helical systems

    International Nuclear Information System (INIS)

    Itoh, Kimitaka; Itoh, Sanae

    1989-01-01

    A review on recent experimental results and theoretical models on anomalous transport and density limit in toroidal helical devices is presented. Importance of transport problems is discussed. Experiments on Heliotron-E, Wendelstein-VIIA and new devices, i.e., ATF, Wendelstein-VIIAS and CHS, are reviewed and an overview on confinement property is given. From recent experimental results one sees that there are anomalous transport, which increases with temperature, and density limit, and that they limit the energy confinement time as well as the attainable beta value. The confinement characteristics of the scrape off layer plasma and loss cone loss are discussed, and perspectives on the high temperature plasma are given. These anomalous transport and density limit will be difficult obstacles in realizing a reactor grade plasma in helical systems. It is an urgent task to draw a realistic picture of the confinement based on the present data base. The relevant knowledge now would be critically essential for the successful development of the research in 1990's. (author) 102 refs

  19. Internal transport barrier physics in helical systems

    International Nuclear Information System (INIS)

    Yokoyama, M.; Minami, T.; Fujisawa, A.; Herranz, J.; Ida, K.; Yamagishi, O.; Yamada, H.; Maaberg, H.; Beidler, C.D.; Dinklage, A.; Estrada, T.; Castejon, F.; Murakami, S.

    2005-01-01

    The electron internal transport barrier (eITB) has been observed in wide range of helical systems, such as CHS [eg.,1], LHD [eg., 2], TJ-II [eg., 3] and W7-AS [eg., 4]. The eITB isA defined as highly peaked electron temperature (Te) profile with strongly positive radial electric field (Er) in the central region. These observations are reviewed in this paper to understand the device-independent common findings and also to draw the main differences. This is the first report from the International Stellarator Profile Database Activity. The formation of the strong central positive Er has been understood mainly as a result of the ambipolarity of neoclassical electron and ion fluxes, although some additional convective electron flux such as driven by ECRH is required in some situations. This 'neoclassical' physics peculiar to low collisional regime of helical plasmas provides the commonly observed existence of the ECRH power threshold (which is also depending on the density). This is contrastive characteristics to the ITB observed in tokamaks. The dependence of the ECRH power threshold on the magnetic configuration and on the heating scenario among these devices are currently being examined by taking the effective ripple and the trapped particle fraction as parameters to achieve the comprehensive understanding. The roles of low order rational surfaces on the onset of eITB formation and also on its radial size (location of the footpoint of the eITB) have been indicated in inward shifted configurations in LHD (depending on the relative locations of heating position and 2/1 island) and TJ-II (eITB becomes possible at higher density when 3/2 rational is introduced in the plasma core region). It is speculated that, for the latter case, the resonance causes an extra electron flux to trigger the positive Er. The interplay between low order rational surfaces and the formation of eITB still waits for the systematic experiment and theoretical analysis. The external controllability

  20. System assessment of helical reactors in comparison with tokamaks

    International Nuclear Information System (INIS)

    Yamazaki, K.; Imagawa, S.; Muroga, T.; Sagara, A.; Okamura, S.

    2002-10-01

    A comparative assessment of tokamak and helical reactors has been performed using equivalent physics/engineering model and common costing model. Higher-temperature plasma operation is required in tokamak reactors to increase bootstrap current fraction and to reduce current-drive (CD) power. In helical systems, lower-temperature operation is feasible and desirable to reduce helical ripple transport. The capital cost of helical reactor is rather high, however, the cost of electricity (COE) is almost same as that of tokamak reactor because of smaller re-circulation power (no CD power) and less-frequent blanket replacement (lower neutron wall loading). The standard LHD-type helical reactor with 5% beta value is economically equivalent to the standard tokamak with 3% beta. The COE of lower-aspect ratio helical reactor is on the same level of high-β N tokamak reactors. (author)

  1. High performance operational limits of tokamak and helical systems

    International Nuclear Information System (INIS)

    Yamazaki, Kozo; Kikuchi, Mitsuru

    2003-01-01

    The plasma operational boundaries of tokamak and helical systems are surveyed and compared with each other. Global confinement scaling laws are similar and gyro-Bohm like, however, local transport process is different due to sawtooth oscillations in tokamaks and ripple transport loss in helical systems. As for stability limits, achievable tokamak beta is explained by ideal or resistive MHD theories. On the other hand, beta values obtained so far in helical system are beyond ideal Mercier mode limits. Density limits in tokamak are often related to the coupling between radiation collapse and disruptive MHD instabilities, but the slow radiation collapse is dominant in the helical system. The pulse length of both tokamak and helical systems is on the order of hours in small machines, and the longer-pulsed good-confinement plasma operations compatible with radiative divertors are anticipated in both systems in the future. (author)

  2. Deflection system of a high-speed streak camera in the form of a delay line

    International Nuclear Information System (INIS)

    Korzhenevich, I.M.; Fel'dman, G.G.

    1993-01-01

    This paper presents an analysis of the operation of a meander deflection system, well-known in oscillography, when it is used to scan the image in a streak-camera tube. Effects that are specific to high-speed photography are considered. It is shown that such a deflection system imposes reduced requirements both on the steepness and on the duration of the linear leading edges of the pulses of the spark gaps that generate the sweep voltage. An example of the design of a meander deflection system whose sensitivity is a factor of two higher than for a conventional system is considered. 5 refs., 3 figs

  3. Space vehicle electromechanical system and helical antenna winding fixture

    Science.gov (United States)

    Judd, Stephen; Dallmann, Nicholas; Guenther, David; Enemark, Donald; Seitz, Daniel; Martinez, John; Storms, Steven

    2017-12-26

    A space vehicle electromechanical system may employ an architecture that enables convenient and practical testing, reset, and retesting of solar panel and antenna deployment on the ground. A helical antenna winding fixture may facilitate winding and binding of the helical antenna.

  4. Multipath Suppression with an Absorber for UWB Wind Turbine Blade Deflection Sensing Systems

    DEFF Research Database (Denmark)

    Zhang, Shuai; Franek, Ondrej; Eggers, Patrick Claus F.

    2017-01-01

    The deflection of a wind turbine blade can be monitored with an ultra-wideband (UWB) deflection sensing system which consists of one transmitting antenna at the blade tip and two receiving antennas at the blade root. The blade deflection is calculated by two estimated tip-root antenna distances...... verifications of the proposed method are carried out with different full-blade measurements. From all the results, it is found that the proposed technique can efficiently suppress multipath for the in-blade tip antenna, and improve the pulse wave front fidelity, so that the UWB sensing system can also...

  5. Effect of shear strain on the deflection of a clamped magnetostrictive film-substrate system

    International Nuclear Information System (INIS)

    Ming Zhenghui; Ming Li; Bo Zou; Xia Luo

    2011-01-01

    The effect of in-plane shear strain of a clamped bimorph on the deflection produced by magnetization of the film is investigated. The deflection is found by minimizing the Gibbs free energy with respect to four parameters, strains and curvatures along x and y directions at the interface, by assuming that the curvature in the y direction varies as a function of aspect ratio w/l along x. A set of standard linear equations of four parameters are obtained and the deflection is expressed in terms of the four parameters by solving the equations using Cramer rules. The inconsistencies pointed out by previous authors are also reviewed. For actuators made of thick and short clamped film-substrate system, the in-plane shear deformation should not be omitted. The present calculation model can give a relatively simple and accurate prediction of deflection for thick and short specimens of aspect ratio w/l<10, which supports the results obtained by finite element modeling. - Highlights: → We model the deflection of a thick magnetostrictive film-substrate cantilever plate. → Total stress along z from magnetic field is not zero without external force. → Effect of in-plane shear strain in calculating deflection examined. → Analytical solution of deflection obtained by assuming a curvature function. → Shear strain for short cantilever film-substrate plate considered.

  6. Linear local stability of electrostatic drift modes in helical systems

    International Nuclear Information System (INIS)

    Yamagishi, O.; Nakajima, N.; Sugama, H.; Nakamura, Y.

    2003-01-01

    We investigate the stability of the drift wave in helical systems. For this purpose, we solve the linear local gyrokinetic-Poisson equation, in the electrostatic regime. As a model of helical plasmas, Large helical Device (LHD) is considered. The equation we apply is rather exact in the framework of linear gyrokinetic theory, where only the approximation is the ballooning representation. In this paper, we consider only collisionless cases. All the frequency regime can be naturally reated without any assumptions, and in such cases, ion temperature gradient modes (ITG), trapped electron modes (TEM), and electron temperature gradient modes (ETG) are expected to become unstable linearly independently. (orig.)

  7. Design and development of a chopping and deflecting system for the high current injector at IUAC

    Science.gov (United States)

    Kedia, Sanjay Kumar; Mehta, R.

    2018-05-01

    The Low Energy Beam Transport (LEBT) section of the High Current Injector (HCI) incorporates a Chopping cum Deflecting System (CDS). The CDS comprises of a deflecting system and a pair of slits that will remove dark current and produce time bunched beam of 60 ns at different repetition rates of 4, 2, 1, 0.5, 0.25 and 0.125 MHz. The distinguishing feature of the design is the use of a multi-plate deflecting structure with low capacitance to optimize the electric field, which in turn results in higher efficiency in terms of achievable ion current. To maximize the effective electric field and its uniformity, the gap between the deflecting plates has been varied and a semi-circular contour has been incorporated on the deflecting plates. Due to this the electric field variation is less than ±0.5% within the plate length. The length of deflecting plates was chosen to maximize the transmission efficiency. Since the velocity of the charged particles in the LEBT section is constant, therefore the separation between two successive sets of deflecting plates has been kept constant to match the ions transient time within the gap which is nearly 32 ns. A square pulse has been chosen, instead of a sinusoidal one, to increase the transmission efficiency and to decrease the tailing effect. The loaded capacitance of the structure was kept 90% transmission efficiency with in the bunch length. Various simulation codes like Solid Works, TRACE 3D, CST MWS and homebrew Python codes were used to validate the design.

  8. Characterization of the protective capacity of flooring systems using force-deflection profiling.

    Science.gov (United States)

    Glinka, Michal N; Karakolis, Thomas; Callaghan, Jack P; Laing, Andrew C

    2013-01-01

    'Safety floors' aim to decrease the risk of fall-related injuries by absorbing impact energy during falls. Ironically, excessive floor deflection during walking or standing may increase fall risk. In this study we used a materials testing system to characterize the ability of a range of floors to absorb energy during simulated head and hip impacts while resisting deflection during simulated single-leg stance. We found that energy absorption for all safety floors (mean (SD)=14.8 (4.9)J) and bedside mats (25.1 (9.3)J) was 3.2- to 5.4-fold greater than the control condition (commercial carpet). While footfall deflections were not significantly different between safety floors (1.8 (0.7)mm) and the control carpet (3.7 (0.6)mm), they were significantly higher for two bedside mats. Finally, all of the safety floors, and two bedside mats, displayed 3-10 times the energy-absorption-to-deflection ratios observed for the baseline carpet. Overall, these results suggest that the safety floors we tested effectively addressed two competing demands required to reduce fall-related injury risk; namely the ability to absorb substantial impact energy without increasing footfall deflections. This study contributes to the literature suggesting that safety floors are a promising intervention for reducing fall-related injury risk in older adults. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

  9. Autonomous shading and light deflection systems; Autarke Sonnenschutz- und Lichtlenksysteme

    Energy Technology Data Exchange (ETDEWEB)

    Klotz, F.H. [Zentrum fuer Sonnenenergie- und Wasserstoff-Forschung Baden-Wuerttemberg (ZSW), Stuttgart (Germany)

    1998-02-01

    The motivations for solar control and daylighting systems at buildings are the reduced use of conventional energy and the improved comfort, for living as well as for working. Light guiding devices can be used in order to obtain daylight still in the deep interior of a building or in order to illuminate special targets. Due to the daily and seasonal changes in the Sun`s position, these devices must be constantly adapted. Using simple and reliable passive thermohydraulic drive technology, many applications for daylighting systems become feasible which were of merely theoretical interest in the past. ZSW has started an initiative for the development of such building-integrated solar systems. This report shows the latest results. (orig.) [Deutsch] Energie- und Umweltaspekte sowie neuere Erkenntnisse der Chronobiologie fordern eine intelligentere und effizientere Architektur und Gebaeudetechnik. Eine zentrale Rolle spielen dabei die transparenten Bauteile (Fenster, Glasfassaden, Atrien, Oberlichter, etc.), da dort der hauptsaechliche Energieaustausch (Waerme, Luft) stattfindet. Eine wirksame Kontrolle dieses Energieflusses - im Kontext der saisonalen und diurnalen Schwankungn der Sonneneinstrahlung - ist der Schluessel zur Reduktion des Gebaeudeenergiebedarfs (Heizung, Kuehlung, Beleuchtung, Lueftung) und der Steigerung des visuellen und thermischen Komforts. Es wurde eine Entwicklungsinitiative fuer passive thermohydraulisch gefuehrte Sonnenschutz- und Lichtlenksysteme gestartet, die durch die Sonne selbst mit Energie versorgt und reguliert werden und damit vollkommen autark sind. Hieraus ergibt sich ein hohes Kostenreduktionspotential fuer den Betrieb solcher Anlagen. Ein Meilenstein dieser Entwicklungen ist der von ZSW fuer die Sonnenlichtlenkung entwickelte erste passive zweiachsig nachgefuehrte Heliostat, welcher bereits seit 16 Monaten stoerungsfrei in Betrieb ist. (orig.)

  10. Properties of the transfer matrices of deflecting magnet systems for free electron laser

    International Nuclear Information System (INIS)

    Takao, Masaru

    1993-01-01

    The oscillation of the free electron laser (FEL) requires the high current and low emittance electron beam. The beam transport system should be achromatic and isochronous to preserve the brightness and the emittance of the electron beam. In this paper we clarify the algebraic properties of the transfer matrices of the magnetic deflection system, which is a key component in the beam transport line. (author)

  11. Plasma transport simulation modeling for helical confinement systems

    International Nuclear Information System (INIS)

    Yamazaki, K.; Amano, T.

    1991-08-01

    New empirical and theoretical transport models for helical confinement systems are developed based on the neoclassical transport theory including the effect of radial electric field and multi-helicity magnetic components, and the drift wave turbulence transport for electrostatic and electromagnetic modes, or the anomalous semi-empirical transport. These electron thermal diffusivities are compared with CHS (Compact Helical System) experimental data, which indicates that the central transport coefficient of the ECH plasma agrees with the neoclassical axi-symmetric value and the transport outside the half radius is anomalous. On the other hand, the transport of NBI-heated plasmas is anomalous in the whole plasma region. This anomaly is not explained by the electrostatic drift wave turbulence models in these flat-density-profile discharges. For the detailed prediction of plasma parameters in LHD (Large Helical Device), 3-D(dimensional) equilibrium/1-D transport simulations including empirical or drift wave turbulence models are carried out, which suggests that the global confinement time of LHD is determined mainly by the electron anomalous transport near the plasma edge region rather than the helical ripple transport in the core region. Even if the ripple loss can be eliminated, the increase of the global confinement is 10%. However, the rise in the central ion temperature is more than 20%. If the anomalous loss can be reduced to the half level of the present scaling, like so-called 'H-mode' of the tokamak discharge, the neoclassical ripple loss through the ion channel becomes important even in the plasma core. The 5% radial inward shift of the plasma column with respect to the major radius is effective for improving plasma confinement and raising more than 50% of the fusion product by reducing this neoclassical asymmetric ion transport loss and increasing 10% in the plasma radius. (author)

  12. Plasma transport simulation modelling for helical confinement systems

    International Nuclear Information System (INIS)

    Yamazaki, K.; Amano, T.

    1992-01-01

    New empirical and theoretical transport models for helical confinement systems are developed on the basis of the neoclassical transport theory, including the effect of the radial electric field and of multi-helicity magnetic components as well as the drift wave turbulence transport for electrostatic and electromagnetic modes or the anomalous semi-empirical transport. These electron thermal diffusivities are compared with experimental data from the Compact Helical System which indicate that the central transport coefficient of a plasma with electron cyclotron heating agrees with neoclassical axisymmetric value and the transport outside the half-radius is anomalous. On the other hand, the transport of plasmas with neutral beam injection heating is anomalous in the whole plasma region. This anomaly is not explained by the electrostatic drift wave turbulence models in these discharges with flat density profiles. For a detailed prediction of the plasma parameters in the Large Helical Device (LHD), 3-D equilibrium/1-D transport simulations including empirical or drift wave turbulence models are performed which suggest that the global confinement time of the LHD is determined mainly by the electron anomalous transport in the plasma edge region rather than by the helical ripple transport in the core region. Even if the ripple loss can be eliminated, the increase in global confinement is 10%. However, the rise in the central ion temperature is more than 20%. If the anomalous loss can be reduced to half of the value used in the present scaling, as is the case in the H-mode of tokamak discharges, the neoclassical ripple loss through the ion channel becomes important even in the plasma core. The 5% radial inward shift of the plasma column with respect to the major radius improves the plasma confinement and increases the fusion product by more than 50% by reducing the neoclassical asymmetric ion transport loss and increasing the plasma radius (10%). (author). 32 refs, 7 figs

  13. A multichannel deflection plates control system for the ALF facility at the APS

    International Nuclear Information System (INIS)

    Deriy, B.

    2006-01-01

    A deflection plates control system was developed as part of SPIRIT (Single Photon Ionization/Resonant Ionization to Threshold), a new secondary neutral mass spectrometry (SNMS) instrument that uses tunable vacuum ultraviolet light from the APS ALF (Argonne Linear Free-electron laser) facility for postionization. The system comprises a crate controller with PC104 embedded computer, 32 amplifiers, and two 1-kV power supplies. Thirty-two D/A converters are used to control voltages at the deflection plates within ± 400 V with 100-mV resolution. An algorithm for simultaneous sweeping of up to 16 XY areas with 10-(micro)s time resolution also has been implemented in the embedded computer. The purpose of the system is to supply potentials to various ion optical elements for electrostatic control of keV primary and secondary ion beams in this SNMS instrument. The control system is of particular value in supplying (1) bipolar potentials for steering ions, (2) multiple potentials for octupole lenses that shape the ion beams, and (3) ramped deflection potentials for rastering the primary ion beam. The system has been in use as part of the SPIRIT instrument at the ALF facility since 2002.

  14. Deflection Control in Composite Building by Using Belt Truss and Outriggers Systems

    OpenAIRE

    S. Fawzia; T. Fatima

    2010-01-01

    The design of high-rise building is more often dictated by its serviceability rather than strength. Structural Engineers are always striving to overcome challenge of controlling lateral deflection and storey drifts as well as self weight of structure imposed on foundation. One of the most effective techniques is the use of outrigger and belt truss system in Composite structures that can astutely solve the above two issues in High-rise constructions. This paper investig...

  15. Dynamics and control of a solar collector system for near Earth object deflection

    International Nuclear Information System (INIS)

    Gong Shenping; Li Junfeng; Gao Yunfeng

    2011-01-01

    A solar collector system is a possible method using solar energy to deflect Earth-threatening near-Earth objects. We investigate the dynamics and control of a solar collector system including a main collector (MC) and secondary collector (SC). The MC is used to collect the sunlight to its focal point, where the SC is placed and directs the collected light to an asteroid. Both the relative position and attitude of the two collectors should be accurately controlled to achieve the desired optical path. First, the dynamical equation of the relative motion of the two collectors in the vicinity of the asteroid is modeled. Secondly, the nonlinear sliding-mode method is employed to design a control law to achieve the desired configuration of the two collectors. Finally, the deflection capability of this solar collector system is compared with those of the gravitational tractor and solar sail gravitational tractor. The results show that the solar collector is much more efficient with respect to deflection capability.

  16. MODELING SUPERSONIC-JET DEFLECTION IN THE HERBIG–HARO 110-270 SYSTEM WITH HIGH-POWER LASERS

    International Nuclear Information System (INIS)

    Yuan, Dawei; Li, Yutong; Lu, Xin; Yin, Chuanlei; Su, Luning; Liao, Guoqian; Zhang, Jie; Wu, Junfeng; Wang, Lifeng; He, Xiantu; Zhong, Jiayong; Wei, Huigang; Zhang, Kai; Han, Bo; Zhao, Gang; Jiang, Shaoen; Du, Kai; Ding, Yongkun; Zhu, Jianqiang

    2015-01-01

    Herbig–Haro (HH) objects associated with newly born stars are typically characterized by two high Mach number jets ejected in opposite directions. However, HH 110 appears to only have a single jet instead of two. Recently, Kajdi et al. measured the proper motions of knots in the whole system and noted that HH 110 is a continuation of the nearby HH 270. It has been proved that the HH 270 collides with the surrounding mediums and is deflected by 58°, reshaping itself as HH 110. Although the scales of the astrophysical objects are very different from the plasmas created in the laboratory, similarity criteria of physical processes allow us to simulate the jet deflection in the HH 110/270 system in the laboratory with high power lasers. A controllable and repeatable laboratory experiment could give us insight into the deflection behavior. Here we show a well downscaled experiment in which a laser-produced supersonic-jet is deflected by 55° when colliding with a nearby orthogonal side-flow. We also present a two-dimensional hydrodynamic simulation with the Euler program, LARED-S, to reproduce the deflection. Both are in good agreement. Our results show that the large deflection angle formed in the HH 110/270 system is probably due to the ram pressure from a flow–flow collision model

  17. Development of Integrated Simulation System for Helical Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Y.; Yokoyama, M.; Nakajima, N.; Fukuyama, A.; Watanabe, K. Y.; Funaba, H.; Suzuki, Y.; Murakami, S.; Ida, K.; Sakakibara, S.; Yamada, H.

    2005-07-01

    Recent progress of computers (parallel/vector-parallel computers, PC clusters, for example) and numerical codes for helical plasmas like three-dimensional MHD equilibrium codes, combined with the development of the plasma diagnostics technique, enable us to do the detailed theoretical analyses of the individual experimental observations. Now, it is pointed out that the experimental data analysis from the viewpoints of integrated physics is an important issue to understand the confinement physics globally. In addition to that, there are international movements towards the integrated numerical simulation study. One is several proposals of integrated modeling of burning tokamak plasmas, motivated by the ITER activity. The integrated numerical simulation will be a good help to draw up new experimental plans especially for burning plasma experiments. Another movement is international collaborations on the confinement database and neoclassical transport in helical plasmas/stellarators. These backgrounds motivate us to start the development of the integrated simulation system which has a modular structure and user-friendly interfaces. The integrated simulation system, which is based on the hierarchical and multi-scale (time and space) modeling, will also be a platform for theoreticians to test their own model such as turbulent transport model. In this paper, we will show the strategy of developing the integrated simulation system and present status of the development. Especially, we discuss the modeling of the time evolution of the plasma net current profile, which is equivalent to the time evolution of the rotational transform profile, in the resistive time scale. (Author)

  18. Electron cyclotron beam measurement system in the Large Helical Device

    Energy Technology Data Exchange (ETDEWEB)

    Kamio, S., E-mail: kamio@nifs.ac.jp; Takahashi, H.; Kubo, S.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Ito, S.; Kobayashi, S.; Mizuno, Y.; Okada, K.; Osakabe, M.; Mutoh, T. [National Institute for Fusion Science, Toki 509-5292 (Japan)

    2014-11-15

    In order to evaluate the electron cyclotron (EC) heating power inside the Large Helical Device vacuum vessel and to investigate the physics of the interaction between the EC beam and the plasma, a direct measurement system for the EC beam transmitted through the plasma column was developed. The system consists of an EC beam target plate, which is made of isotropic graphite and faces against the EC beam through the plasma, and an IR camera for measuring the target plate temperature increase by the transmitted EC beam. This system is applicable to the high magnetic field (up to 2.75 T) and plasma density (up to 0.8 × 10{sup 19} m{sup −3}). This system successfully evaluated the transmitted EC beam profile and the refraction.

  19. Relational dynamics in the multi-helices knowledge production system

    DEFF Research Database (Denmark)

    Thai, Thi Minh; Hjortsø, Carsten Nico Portefée

    -level dynamics are characterized by political ambidexterity that enables the state to maintain control by privileging traditional science and education constituencies, and at the same time support the transition of the knowledge production system towards international methodology and quality standards through......Drawing on the triple helix framework and organizational institutionalism, this article applies a qualitative research approach to analyze structures, institutional logics, power relations that shape inter-organizational relations and the structuration of a knowledge production system...... in an emerging economy. Findings highlight the emergence of a fifth-helices knowledge production system includes the state, science and education, industry, international actors, and society. The system comprises two major segments, one associated with the traditional command economy and characterized...

  20. A broadband helical saline water liquid antenna for wearable systems

    Science.gov (United States)

    Li, Gaosheng; Huang, Yi; Gao, Gui; Yang, Cheng; Lu, Zhonghao; Liu, Wei

    2018-04-01

    A broadband helical liquid antenna made of saline water is proposed. A transparent hollow support is employed to fabricate the antenna. The rotation structure is fabricated with a thin flexible tube. The saline water with a concentration of 3.5% can be injected into or be extracted out from the tube to change the quantity of the solution. Thus, the tunability of the radiation pattern could be realised by applying the fluidity of the liquid. The radiation feature of the liquid antenna is compared with that of a metal one, and fairly good agreement has been achieved. Furthermore, three statements of the radiation performance corresponding to the ratio of the diameter to the wavelength of the helical saline water antenna have been proposed. It has been found that the resonance frequency increases when the length of the feeding probe or the radius of the vertical part of the liquid decreases. The fractional bandwidth can reach over 20% with a total height of 185 mm at 1.80 GHz. The measured results indicate reasonable approximation to the simulated. The characteristics of the liquid antenna make it a good candidate for various wireless applications, especially the wearable systems.

  1. Persistent spin helices in 2D electron systems

    Science.gov (United States)

    Kozulin, A. S.; Malyshev, A. I.; Konakov, A. A.

    2017-03-01

    We present a theoretical investigation of persistent spin helices in two-dimensional electron systems with spin-orbit coupling. For this purpose, we consider a single-particle effective mass Hamiltonian with a generalized linear-in- k spin-orbit coupling term corresponding to a quantum well grown in an arbitrary crystallographic direction, and derive the general condition for the formation of the persistent spin helix. This condition applied for the Hamiltonians describing quantum wells with different growth directions indicates the possibility of existence of the persistent spin helix in a wide class of 2D systems apart from the [001] model with equal Rashba and Dresselhaus spin-orbit coupling strengths and the [110] Dresselhaus model.

  2. Edge transport barrier formation in compact helical system

    International Nuclear Information System (INIS)

    Okamura, S; Minami, T; Oishi, T; Suzuki, C; Ida, K; Isobe, M; Yoshimura, Y; Nagaoka, K; Toi, K; Fujisawa, A; Akiyama, T; Iguchi, H; Ikeda, R; Kado, S; Matsuoka, K; Matsushita, H; Nakamura, K; Nakano, H; Nishimura, S; Nishiura, M; Ohshima, S; Shimizu, A; Takagi, S; Takahashi, C; Takeuchi, M; Yoshinuma, M

    2004-01-01

    The edge transport barrier (ETB) for particle transport is formed in the neutral beam (NB) heated hydrogen discharges in compact helical system (CHS). The transition to the ETB formation and the back transition are controlled by the heating power. The existence of the heating power threshold is confirmed and it is roughly proportional to the density. The Hα emission signal shows a clear drop at the transition (the timescale of signal decrease is ∼1 ms for the high heating power case). The ETB formation continues for the full duration of NB injection (100 ms) with a moderate level of radiation power loss. Local density profile measurement shows increase of the edge density and the movement of the density gradient region towards the edge

  3. Measurements of Beam Ion Loss from the Compact Helical System

    International Nuclear Information System (INIS)

    Darrow, D.S.; Isobe, M.; Kondo, Takashi; Sasao, M.

    2010-01-01

    Beam ion loss from the Compact Helical System (CHS) has been measured with a scintillator-type probe. The total loss to the probe, and the pitch angle and gyroradius distributions of that loss, have been measured as various plasma parameters were scanned. Three classes of beam ion loss were observed at the probe position: passing ions with pitch angles within 10o of those of transition orbits, ions on transition orbits, and ions on trapped orbits, typically 15o or more from transition orbits. Some orbit calculations in this geometry have been performed in order to understand the characteristics of the loss. Simulation of the detector signal based upon the following of orbits from realistic beam deposition profiles is not able to reproduce the pitch angle distribution of the losses measured. Consequently it is inferred that internal plasma processes, whether magnetohydrodynamic modes, radial electric fields, or plasma turbulence, move previously confined beam ions to transition orbits, resulting in their loss.

  4. Design of central control system for large helical device (LHD)

    International Nuclear Information System (INIS)

    Yamazaki, K.; Kaneko, H.; Yamaguchi, S.; Watanabe, K.Y.; Taniguchi, Y.; Motojima, O.

    1993-11-01

    The world largest superconducting fusion machine LHD (Large Helical Device) is under construction in Japan, aiming at steady state operations. Its basic control system consists of UNIX computers, FDDI/Ethernet LANs, VME multiprocessors and VxWorks real-time OS. For flexible and reliable operations of the LHD machine a cooperative distributed system with more than 30 experimental equipments is controlled by the central computer and the main timing system, and is supervised by the main protective interlock system. Intelligent control systems, such as applications of fuzzy logic and neural networks, are planed to be adopted for flexible feedback controls of plasma configurations besides the classical PID control scheme. Design studies of its control system and related R and D programs with coil-plasma simulation systems are now being performed. The construction of the LHD Control Building in a new site will begin in 1995 after finishing the construction of the LHD Experimental Building, and the hardware construction of the LHD central control equipments will be started in 1996. A first plasma production by means of this control system is expected in 1997. (author)

  5. Recent Results of Helical Nonneutral Plasmas on Compact Helical System (CHS)

    International Nuclear Information System (INIS)

    Himura, H.; Yamamoto, Y.; Sanpei, A.; Masamune, S.; Wakabayashi, H.; Isobe, M.

    2006-01-01

    First of all, non-constant space potential φs and electron density ne on magnetic surfaces of helical nonneutral plasmas are verified experimentally. The difference in φs enlarges significantly at the outer region inside the closed magnetic surfaces, and the corresponding equipotential surfaces are inferred to shift upward vertically with respect to magnetic surfaces. Meanwhile, larger value of ne is clearly observed in the downward region (z < 0) of magnetic surfaces, which seems to be consistent with the φs measurement. These results are the first evidence which strongly suggests the equilibrium proposed for nonneutral plasmas confined in closed magnetic surfaces. Secondly, in order to investigate the mechanism of the multiple disruption of helical nonneutral plasmas observed in experiments, space and time evolutions of electron flux are measured carefully inside the magnetic surfaces, when the plasma disruption occurs. Surprisingly, a set of data show that the observed disruption is at first happened at ρ ∼ 0.8, where ρ is the normalized minor radius, and then, it seems to propagate inside magnetic surfaces

  6. Modernizing and Upgrading the Astrogeodetic Camera System for Determining Vertical Deflections

    Science.gov (United States)

    Albayrak, M.; Halicioglu, K.; Basoglu, B.; Ulug, R.; Ozludemir, M. T.; Deniz, R.

    2017-12-01

    The geoid is the equipotential surface of the Earth. Modeling the geoid with high accuracy is one of the critical issues in Geodesy. Development of geoid modeling is based on geodetic, gravimetric and astrogeodetic techniques. In order to reach the intended accuracy, deflection of the vertical (VD) components, which is obtained by the astrogeodetic techniques, can be used. VD is also very important for providing valuable information on the structure of Earth's gravity field. For this reason, astrogeodetic observations were essential gravity field observables and used for astrogeodetic geoid determinations. Scientists in several countries have developed modern instruments to measure vertical deflections. One of those instruments, namely Astro-geodetic Camera System (ACSYS) was developed in Turkey in 2015. The system components include a telescope, a Charged Coupled Device (CCD), two tiltmeters with the accuracy of 0.01 milliradians, a focuser, a single frequency GPS receiver and a substructure. The first version of the ACSYS is capable of determining astronomical coordinates with an accuracy of 0.2-0.3 arc sec, yet it has some limitations in observation duration. Because of the semi-automated mechanical design, leveling the system towards zenith was a time-consuming process. Since the beginning of 2016, the ACSYS has been modernized through the upgrade of the system with new technological components, hardware and software which is supported by The Scientific and Research Council of Turkey. Upgrade process includes the installation of a high-resolution tiltmeter with an accuracy of 1 nano-radians, implementation of a temperature compensating focuser and fully automatized substructure system. The components of the system are controlled by specially designed and integrated software. In the scope of the modernization studies, the project team has also been working on a unified real-time processing and control software for the ACSYS.v2. This study introduces the

  7. Pressure-induced shift of the plasma in a helical system with ideally conducting wall

    International Nuclear Information System (INIS)

    Pustovitov, V.D.

    2004-01-01

    The global plasma shift is calculated analytically for a helical system with an ideal wall. The derived expression for the plasma shift, incorporating both the finite-β plasma expansion and the opposing reaction of the nearby ideal wall, can be used for interpreting the observable high-β equilibrium effects in LHD and other helical devices. (author)

  8. Measuring Time-Dependent Pavement Deflection Profiles Under Drive-by Conditions with a Portable System

    National Research Council Canada - National Science Library

    Peekna, Andres

    2002-01-01

    .... The investigation showed that in order to credibly extrapolate from sensors away from the tires to deflection underneath the tires, a laterally separated pair of sensors at each longitudinal location would be necessary...

  9. Improved confinement and related physics study in Compact Helical System

    International Nuclear Information System (INIS)

    Okamura, S.; Akiyama, T.; Fujisawa, A.; Ida, K.; Iguchi, H.; Isobe, M.; Minami, T.; Nagaoka, K.; Nakamura, K.; Nishimura, S.; Matsuoka, K.; Matsushita, H.; Nakano, H.; Ohshima, S.; Shimizu, A.; Suzuki, C.; Takahashi, C.; Toi, K.; Yoshimura, Y.; Yoshinuma, M.; Oishi, T.; Kado, S.

    2005-01-01

    Recent experimental results in Compact Helical System (CHS) will be presented focusing on the improved confinement and physics study of electric field and turbulence in helical plasmas. Among various improved confinement modes found in CHS experiments, the edge transport barrier (ETB) formation is an important topic, which we have been studying intensively for these years. The discharges of CHS with ETB have characteristics very similar to H-mode discharges in tokamaks and W7-AS stellarator. We observe a sharp drop of Hα emission signal, increase of plasma density together with an increase of local density gradient at the plasma edge, so we call our ETB discharges as H-mode. The power threshold for the transition is clearly observed which is again similar to standard H-mode discharges, i.e., the threshold increases with the density and magnetic field. Unique feature of CHS H-mode is the dependence on the magnetic field configuration. We examined H-mode discharges for the configurations with magnetic axis shift and the magnetic quadrupole control. The transition appeared for a wide range of configurations with the rotational transform at the plasma edge (iota(a)) below and above unity. There is a general dependence of power threshold: higher power needed for the inward shifted configuration (with lower value of iota(a)) and lower power for outward shift. The absolute power threshold of CHS H-mode for the outward shifted configuration is very close to the tokamak H-mode with a divertor configuration. Other topics of confinement studies in CHS will be also presented. We have a unique diagnostic system of two heavy ion beam probes. It is unique in stellarator research and also for all toroidal confinement research including many tokamaks in the world. As well as fruitful result of electric field measurements, that is one of key elements for stellarator physics, this diagnostic measures turbulence in the plasma, which gives essential information for the study of

  10. Laser self-mixing interferometry in VCSELs - an ultra-compact and massproduceable deflection detection system for nanomechanical polymer cantilever sensors

    DEFF Research Database (Denmark)

    Larsson, David; Yvind, Kresten; Hvam, Jørn Märcher

    2008-01-01

    We have realised an ultra-compact deflection detection system based on laser self-mixing interferometry in a Vertical-Cavity Surface-Emitting Laser (VCSEL). The system can be used together with polymer nanomechanical cantilevers to form chemical sensors capable of detecting less than 1nm deflection....

  11. New Modular Heliotron system compatible with closed helical divertor and good plasma confinement

    International Nuclear Information System (INIS)

    Yamazaki, K.; Watanabe, K.Y.

    1994-04-01

    A new helical system ('Modular Heliotron') with improved modular coils compatible with efficient closed helical divertor and good plasma confinement property is proposed based on a Heliotron system with continuous helical coils and one pair of poloidal coils. The physics optimization of this system as a function of the gap angle between adjacent modular coils has been carried out by means of vacuum magnetic surface calculations and finite-beta plasma analyses, and a new improved coil system is invented by combining sectored helical field coils with sectored returning poloidal field coils. The Modular Heliotron with standard coil winding law (reference Modular Heliotron) was previously proposed, but it is found that this is not appropriate to keep clean helical divertor and high beta configuration when the coil gap becomes large. By modulating the modular coil winding with outside-plus and inside-minus pitch modulation, almost the same good magnetic configuration as that of a conventional Heliotron can be produced. The optimal gap angle is determined as a function of the modulation parameter. This improved Modular Heliotron permits larger gap angle between adjacent modules and produces more clean helical divertor configuration than the reference Modular Heliotron. All these helical system are created by only modular coils without poloidal coils. (author)

  12. New modular heliotron system compatible with closed helical divertor and good plasma confinement

    International Nuclear Information System (INIS)

    Yamazaki, K.; Watanabe, K.Y.

    1995-01-01

    A new helical system ('modular heliotron') with improved modular coils compatible with an efficient closed helical divertor and a good plasma confinement property is proposed, based on a heliotron system with continuous helical coils and one pair of poloidal coils. The physics optimization of this system as a function of the gap angle between adjacent modular coils has been carried out by means of vacuum magnetic surface calculations and finite-beta plasma analyses, and a new improved coil system is invented by combining sectored helical field coils with sectored returning poloidal field coils. A modular heliotron with standard coil winding law (the reference modular heliotron) was previously proposed, but it is found that this was not appropriate to keep a clean helical divertor and high beta configuration when the coil gap becomes large. By modulating the modular coil winding with outside-plus and inside-minus pitch modulation, almost the same good magnetic configuration as that of a conventional heliotron can be produced. The optimal gap angle is determined as a function of the modulation parameter. This improved modular heliotron permits a larger gap angle between adjacent modules and produces a cleaner helical divertor configuration than the reference modular heliotron. All these helical systems are created by only modular coils without poloidal coils. (author). Letter-to-the-editor. 11 refs, 7 figs

  13. Electron beam deflection control system of a welding and surface modification installation

    Science.gov (United States)

    Koleva, E.; Dzharov, V.; Gerasimov, V.; Tsvetkov, K.; Mladenov, G.

    2018-03-01

    In the present work, we examined the patterns of the electron beam motion when controlling the transverse with respect to the axis of the beam homogeneous magnetic field created by the coils of the deflection system the electron gun. During electron beam processes, the beam motion is determined the process type (welding, surface modification, etc.), the technological mode, the design dimensions of the electron gun and the shape of the processed samples. The electron beam motion is defined by the cumulative action of two cosine-like control signals generated by a functional generator. The signal control is related to changing the amplitudes, frequencies and phases (phase differences) of the generated voltages. We realized the motion control by applying a graphical user interface developed by us and an Arduino Uno programmable microcontroller. The signals generated were calibrated using experimental data from the available functional generator. The free and precise motion on arbitrary trajectories determines the possible applications of an electron beam process to carrying out various scientific research tasks in material processing.

  14. Edge plasma diagnostics in the compact helical system (CHS) device using fast neutral lithium beam

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, Mario

    1992-05-01

    This paper reports the research activities of the author on using fast neutral lithium beam edge plasma diagnostic, at the Japanese National Institute for Fusion Science compact helical system (CHS). (author). 20 figs.

  15. Active trajectory control for a heavy ion beam probe on the compact helical system

    International Nuclear Information System (INIS)

    Fujisawa, A.; Iguchi, H.; Lee, S.; Crowley, T.P.; Hamada, Y.; Hidekuma, S.; Kojima, M.

    1996-05-01

    A 200 keV heavy ion beam probe (HIBP) on the Compact Helical System torsatron/heliotron uses a newly proposed method in order to control complicated beam trajectories in non-axisymmetrical devices. As a result, the HIBP has successfully measured potential profiles of the toroidal helical plasma. The article will describe the results of the potential profile measurements, together with the HIBP hardware system and procedures to realize the method. (author)

  16. Neutronics investigation of advanced self-cooled liquid blanket systems in helical reactor

    International Nuclear Information System (INIS)

    Tanaka, T.; Sagara, A.; Muroga, T.; Youssef, M.Z.

    2006-10-01

    Neutronics performances of advanced self-cooled liquid blanket systems have been investigated in design activity of the helical-type reactor FFHR2. In the present study, a new three-dimensional (3-D) neutronics calculation system has been developed for the helical-type reactor to enhance quick feedback between neutronics evaluation and design modification. Using this new calculation system, advanced Flibe-cooled and Li-cooled liquid blanket systems proposed for FFHR2 have been evaluated to make clear design issues to enhance neutronics performance. Based on calculated results, modification of the blanket dimensions and configuration have been attempted to achieve the adequate tritium breeding ability and neutron shielding performance in the helical reactor. The total tritium breeding ratios (TBRs) obtained after modifying the blanket dimensions indicated that all the advanced blanket systems proposed for FFHR2 would achieve adequate tritium self-sufficiency by dimension adjustment and optimization of structures in the breeder layers. Issues in neutron shielding performance have been investigated quantitatively using 3-D geometry of the helical blanket system, support structures, poloidal coils etc. Shielding performance of the helical coils against direct neutrons from core plasma would achieve design target by further optimization of shielding materials. However, suppression of the neutron streaming and reflection through the divertor pumping areas in the original design is important issue to protect the poloidal coils and helical coils, respectively. Investigation of the neutron wall loading indicated that the peaking factor of the neutron wall load distribution would be moderated by the toroidal and helical effect of the plasma distribution in the helical reactor. (author)

  17. Radio emission from a helical electron beam-plasma system in a twisted magnetic field

    International Nuclear Information System (INIS)

    Krishan, V.

    1982-01-01

    The excitation of electromagnetic radiation near the harmonics of electron plasma frequency from a helical electron beam travelling parallel to a helical magnetic field through a stationary inhomogeneous plasma is studied. The motivation behind this study is to explain the observed characteristics of the type III solar radio bursts and thus to predict the nature of the plasma system responsible for the generation of these radio bursts. (author)

  18. Microbunch preserving in-line system for an APPLE II helical radiator at the LCLS baseline

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, Gianluca [European XFEL Project Team, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2011-05-15

    In a previous work we proposed a scheme for polarization control at the LCLS baseline, which exploited the microbunching from the planar undulator. After the baseline undulator, the electron beam is transported through a drift by a FODO focusing system, and through a short helical radiator. The microbunching structure can be preserved, and intense coherent radiation is emitted in the helical undulator at fundamental harmonic. The driving idea of this proposal is that the background linearly-polarized radiation from the baseline undulator is suppressed by spatial filtering. Filtering is achieved by letting radiation and electron beam through Be slits upstream of the helical radiator, where the radiation spot size is about ten times larger than the electron beam transverse size. Several changes considered in the present paper were made to improve the previous design. Slits are now placed immediately behind the helical radiator. The advantage is that the electron beam can be spoiled by the slits, and narrower slits width can be used for spatial filtering. Due to this fundamental reason, the present setup is shorter than the previous one. The helical radiator is now placed immediately behind the SHAB undulator. It is thus sufficient to use the existing FODO focusing system of the SHAB undulator for transporting themodulated electron beam. This paper presents complete GENESIS code calculations for the new design, starting from the baseline undulator entrance up to the helical radiator exit including the modulated electron beam transport by the SHAB FODO focusing system. (orig.)

  19. Microbunch preserving in-line system for an APPLE II helical radiator at the LCLS baseline

    International Nuclear Information System (INIS)

    Geloni, Gianluca; Kocharyan, Vitali; Saldin, Evgeni

    2011-05-01

    In a previous work we proposed a scheme for polarization control at the LCLS baseline, which exploited the microbunching from the planar undulator. After the baseline undulator, the electron beam is transported through a drift by a FODO focusing system, and through a short helical radiator. The microbunching structure can be preserved, and intense coherent radiation is emitted in the helical undulator at fundamental harmonic. The driving idea of this proposal is that the background linearly-polarized radiation from the baseline undulator is suppressed by spatial filtering. Filtering is achieved by letting radiation and electron beam through Be slits upstream of the helical radiator, where the radiation spot size is about ten times larger than the electron beam transverse size. Several changes considered in the present paper were made to improve the previous design. Slits are now placed immediately behind the helical radiator. The advantage is that the electron beam can be spoiled by the slits, and narrower slits width can be used for spatial filtering. Due to this fundamental reason, the present setup is shorter than the previous one. The helical radiator is now placed immediately behind the SHAB undulator. It is thus sufficient to use the existing FODO focusing system of the SHAB undulator for transporting themodulated electron beam. This paper presents complete GENESIS code calculations for the new design, starting from the baseline undulator entrance up to the helical radiator exit including the modulated electron beam transport by the SHAB FODO focusing system. (orig.)

  20. Magnetic field structure near the plasma boundary in helical systems and divertor tokamaks

    International Nuclear Information System (INIS)

    Nagasaki, Kazunobu; Itoh, Kimitaka

    1990-02-01

    Magnetic field structure of the scrape off layer (SOL) region in both helical systems and divertor tokamaks is studied numerically by using model fields. The connection length of the field line to the wall is calculated. In helical systems, the connection length, L, has a logarithmic dependence on the distance from the outermost magnetic surface or that from the residual magnetic islands. The effect of axisymmetric fields on the field structure is also determined. In divertor tokamaks, the connection length also has logarithmic properties near the separatrix. Even when the perturbations, which resonate to rational surfaces near the plasma boundary, are added, logarithmic properties still remain. We compare the connection length of torsatron/helical-heliotron systems with that of divertor tokamaks. It is found that the former is shorter than the latter by one order magnitude with similar aspect ratio. (author)

  1. Local Helicity Injection Systems for Non-solenoidal Startup in the PEGASUS Toroidal Experiment

    Science.gov (United States)

    Perry, J. M.; Barr, J. L.; Bongard, M. W.; Fonck, R. J.; Hinson, E. T.; Lewicki, B. T.; Redd, A. J.

    2013-10-01

    Local helicity injection is being developed in the PEGASUS Toroidal Experiment for non-solenoidal startup in spherical tokamaks. The effective loop voltage due to helicity injection scales with the area of the injectors, requiring the development of electron current injectors with areas much larger than the 2 cm2 plasma arc injectors used to date. Solid and gas-effused metallic electrodes were found to be unusable due to reduced injector area utilization from localized cathode spots and narrow operational regimes. An integrated array of 8 compact plasma arc sources is thus being developed for high current startup. It employs two monolithic power systems, for the plasma arc sources and the bias current extraction system. The array effectively eliminates impurity fueling from plasma-material interaction by incorporating a local scraper-limiter and conical-frustum bias electrodes to mitigate the effects of cathode spots. An energy balance model of helicity injection indicates that the resulting 20 cm2 of total injection area should provide sufficient current drive to reach 0.3 MA. At that level, helicity injection drive exceeds that from poloidal induction, which is the relevant operational regime for large-scale spherical tokamaks. Future placement of the injector array near an expanded boundary divertor region will test simultaneous optimization of helicity drive and the Taylor relaxation current limit. Work supported by US DOE Grant DE-FG02-96ER54375.

  2. Implementation of a beam deflection system for studies of liquid interfaces on beamline I07 at Diamond.

    Science.gov (United States)

    Arnold, Thomas; Nicklin, Chris; Rawle, Jonathan; Sutter, John; Bates, Trevor; Nutter, Brian; McIntyre, Gary; Burt, Martin

    2012-05-01

    X-ray optics, based on a double-crystal deflection scheme, that enable reflectivity measurements from liquid surfaces/interfaces have been designed, built and commissioned on beamline I07 at Diamond Light Source. This system is able to deflect the beam onto a fixed sample position located at the centre of a five-circle diffractometer. Thus the incident angle can be easily varied without moving the sample, and the reflected beam is tracked either by a moving Pilatus 100K detector mounted on the diffractometer arm or by a stationary Pilatus 2M detector positioned appropriately for small-angle scattering. Thus the system can easily combine measurements of the reflectivity from liquid interfaces (Q(z) > 1 Å(-1)) with off-specular data collection, both in the form of grazing-incidence small-angle X-ray scattering (GISAXS) or wider-angle grazing-incidence X-ray diffraction (GIXD). The device allows operation over the energy range 10-28 keV.

  3. Conceptual design of the superconducting magnet system for the helical fusion reactor

    International Nuclear Information System (INIS)

    Yanagi, Nagato; Hamaguchi, Shinji; Takahata, Kazuya; Natsume, Kyohei

    2013-01-01

    Current status of conceptual design of superconducting magnet system and low temperature system for the helical fusion reactor are introduced. There are three kinds of candidates of superconducting magnets such as Cable-in-conduit (CIC), Low-Temperature Superconductor (LTS) and High-Temperature Superconductor (HTS). Their characteristic properties, coil designs and cooling systems are stated. The freezer and low temperature distribution system, bus line and current lead, and excitation power source for superconducting coil are reported. The various elements of superconducting magnet system of FFHR-d1, partial cross section of FFHR helical coil using CIC, conceptual diagram of helical coil winding method of FFHR using CIC, relation among mass flow of supercritical helium supplied into CIC conductor and temperature increasing and pressure loss, cross section structure of LTS indirect-cooling conductor at 100 kA, cross section of 100-kA HTS conductor, connection method of helical coil segment and YBCO conductor are illustrated. (S.Y.)

  4. A real-time deflection monitoring system for wind turbine blades using a built-in laser displacement sensor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyeong-Cheol; Giri, Paritosh; Lee, Jung-Ryul [Korea Chonbuk National Univ., Jeonbuk (Korea, Republic of). Dept. of Aerospace Engineering and LANL-CBNU Engineering Inst.

    2012-07-01

    Renewable energy is considered a good alternative to deal with the issues related to fossil fuel and environmental pollution. Wind energy as one of such renewable energy alternatives has seen a substantial growth. With commercially viable global wind power potential, wind energy penetration is further expected to rise, and so will the related problems. One of the issues is the collision of wind blade and tower during operation. To improve safety during operation, to minimize the risk of sudden failure or total breakdown, and to ensure reliable power generation and reduce wind turbine life cycle costs, a structural health monitoring (SHM) technology is required. This study proposes a single laser displacement sensor (LDS) system, where all of the rotating blades could be evaluated effectively. The system is cost-effective as well, as the system costs only a mere thousand dollars. If the blade bolt loosening occurs, it causes deflection in the affected blade. In a similar manner, nacelle tilt or mass loss damage in the blade will result in change of blade's position and the proposed system can identify such problems with ease. With increased demand of energy, the sizes of wind blades are getting bigger and bigger due to which people are installing wind turbines very high above the ground level or offshore. It is impractical to monitor the deflection through wired connection in these cases and hence can be replaced by a wireless solution. This wireless solution is achieved using Zigbee technology which operates in the industrial, scientific and medical (ISM) radio bands, typically 2.4 GHz, 915 MHz and 868 MHz. The output from the LDS is fed to the microcontroller which acts as an analog to digital converter which in turn is connected to the Zigbee transceiver module, which transmits the data. At the other end, the Zigbee reads the data and displays on the PC from where user can monitor the condition of wind blades. (orig.)

  5. Kinetic simulations of neoclassical and anomalous transport processes in helical systems

    International Nuclear Information System (INIS)

    Sugama, Hideo; Watanabe, Tomohiko; Nunami, Masanori; Satake, Shinsuke; Matsuoka, Seikichi; Tanaka, Kenji

    2012-01-01

    Drift kinetic and gyrokinetic theories and simulations are powerful means for quantitative predictions of neoclassical and anomalous transport fluxes in helical systems such as the Large Helical Device (LHD). The δf Monte Carlo particle simulation code, FORTEC-3D, is used to predict radial profiles of the neoclassical particle and heat transport fluxes and the radial electric field in helical systems. The radial electric field profiles in the LHD plasmas are calculated from the ambipolarity condition for the neoclassical particle fluxes obtained by the global simulations using the FORTEC-3D code, in which effects of ion or electron finite orbit widths are included. Gyrokinetic Vlasov simulations using the GKV code verify the theoretical prediction that the neoclassical optimization of helical magnetic configuration enhances the zonal flow generation which leads to the reduction of the turbulent heat diffusivity χ i due to the ion temperature gradient (ITG) turbulence. Comparisons between results for the high ion temperature LHD experiment and the gyrokinetic simulations using the GKV-X code show that the χ i profile and the poloidal wave number spectrum of the density fluctuation obtained from the simulations are in reasonable agreements with the experimental results. It is predicted theoretically and confirmed by the linear GKV simulations that the E × B rotation due to the background radial electric field E r can enhance the zonal-flow response to a given source. Thus, in helical systems, the turbulent transport is linked to the neoclassical transport through E r which is determined from the ambipolar condition for neoclassical particle fluxes and influences the zonal flow generation leading to reduction of the turbulent transport. In order to investigate the E r effect on the regulation of the turbulent transport by the zonal flow generation, the flux-tube bundle model is proposed as a new method for multiscale gyrokinetic simulations. (author)

  6. Imaging Features of Helical Computed Tomography Suggesting Advanced Urothelial Carcinoma Arising from the Pelvocalyceal System

    International Nuclear Information System (INIS)

    Kwak, Kyung Won; Park, Byung Kwan; Kim, Chan Kyo; Lee, Hyun Moo; Choi, Han Y ong

    2008-01-01

    Background: Urothelial carcinoma is the most common malignant tumor arising from the pelvocalyceal system. Helical computed tomography (CT) is probably the best preoperative-stage modality for the determination of treatment plan and prognosis. Purpose: To obtain helical CT imaging features suggesting advanced pelvocalyceal urothelial carcinoma. Material and Methods: Preoperative CT images in 44 patients with pelvocalyceal urothelial carcinoma were retrospectively reviewed and correlated with the pathological examination to determine imaging features suggesting stage III or IV of the disease. Results: Pathological stages revealed stage I in 16, stage II in three, stage III in 17, and stage IV in eight patients. Seven patients had metastatic lymph nodes. CT imaging showed that renal parenchymal invasion, sinus fat invasion, and lymph node metastasis were highly suggestive of advanced urothelial cell carcinoma (P<0.05). Helical CT sensitivity, specificity, and accuracy for advanced pelvocalyceal urothelial carcinoma were 76% (19/25), 84% (16/19), and 80% (35/44), respectively. Conclusion: Preoperative helical CT may suggest imaging features of advanced urothelial carcinoma, influencing treatment plan and patient prognosis, even though its accuracy is not so high

  7. Helical twisting in nemato-cholesteric systems based on cholesterol derivatives and photosensitive azoxy compounds

    Energy Technology Data Exchange (ETDEWEB)

    Serbina, M. I.; Kasian, N. A.; Lisetski, L. N., E-mail: lisetski@isma.kharkov.ua [NAS of Ukraine, Institute for Scintillation Materials, STC ' Institute for Single Crystals' (Ukraine)

    2013-01-15

    For cholesteric liquid crystal systems containing photosensitive nematic ZhK-440 and a mixture of cholesterol derivatives, changes in helical twisting induced by UV radiation were studied. The UV-induced shift of selective reflection maximum {lambda}{sub max} was shown to depend upon concentration of the nematic component. For low concentrations of ZhK-440, {lambda}{sub max} increases, which correlates with corresponding changes with increasing temperature. For higher concentrations, {lambda}{sub max} decreases, regardless of the temperature behavior of the system. A theoretical description of the available experimental data is proposed on the basis of development of molecular models of helical twisting, including an assumed possibility of ordered orientation of short molecular axes of cis-isomers formed as a result of UV irradiation, which is determined by the sense of the cholesteric helix already present in the system.

  8. Non-Abelian parafermions in time-reversal-invariant interacting helical systems

    Science.gov (United States)

    Orth, Christoph P.; Tiwari, Rakesh P.; Meng, Tobias; Schmidt, Thomas L.

    2015-02-01

    The interplay between bulk spin-orbit coupling and electron-electron interactions produces umklapp scattering in the helical edge states of a two-dimensional topological insulator. If the chemical potential is at the Dirac point, umklapp scattering can open a gap in the edge state spectrum even if the system is time-reversal invariant. We determine the zero-energy bound states at the interfaces between a section of a helical liquid which is gapped out by the superconducting proximity effect and a section gapped out by umklapp scattering. We show that these interfaces pin charges which are multiples of e /2 , giving rise to a Josephson current with 8 π periodicity. Moreover, the bound states, which are protected by time-reversal symmetry, are fourfold degenerate and can be described as Z4 parafermions. We determine their braiding statistics and show how braiding can be implemented in topological insulator systems.

  9. Vorticity field, helicity integral and persistence of entanglement in reaction-diffusion systems

    International Nuclear Information System (INIS)

    Trueba, J L; Arrayas, M

    2009-01-01

    We show that a global description of the stability of entangled structures in reaction-diffusion systems can be made by means of a helicity integral. A vorticity vector field is defined for these systems, as in electromagnetism or fluid dynamics. We have found under which conditions the helicity is conserved or lost through the boundaries of the medium, so the entanglement of structures observed is preserved or disappears during time evolution. We illustrate the theory with an example of knotted entanglement in a FitzHugh-Nagumo model. For this model, we introduce new non-trivial initial conditions using the Hopf fibration and follow the time evolution of the entanglement. (fast track communication)

  10. Vorticity field, helicity integral and persistence of entanglement in reaction-diffusion systems

    Energy Technology Data Exchange (ETDEWEB)

    Trueba, J L; Arrayas, M [Area de Electromagnetismo, Universidad Rey Juan Carlos, Camino del Molino s/n, 28943 Fuenlabrada, Madrid (Spain)

    2009-07-17

    We show that a global description of the stability of entangled structures in reaction-diffusion systems can be made by means of a helicity integral. A vorticity vector field is defined for these systems, as in electromagnetism or fluid dynamics. We have found under which conditions the helicity is conserved or lost through the boundaries of the medium, so the entanglement of structures observed is preserved or disappears during time evolution. We illustrate the theory with an example of knotted entanglement in a FitzHugh-Nagumo model. For this model, we introduce new non-trivial initial conditions using the Hopf fibration and follow the time evolution of the entanglement. (fast track communication)

  11. Stereotactic Image-Guided Intensity Modulated Radiotherapy Using the HI-ART II Helical Tomotherapy System

    International Nuclear Information System (INIS)

    Holmes, Timothy W.; Hudes, Richard; Dziuba, Sylwester; Kazi, Abdul; Hall, Mark; Dawson, Dana

    2008-01-01

    The highly integrated adaptive radiation therapy (HI-ART II) helical tomotherapy unit is a new radiotherapy machine designed to achieve highly precise and accurate treatments at all body sites. The precision and accuracy of the HI-ART II is similar to that provided by stereotactic radiosurgery systems, hence the historical distinction between external beam radiotherapy and stereotactic procedures based on differing precision requirements is removed for this device. The objectives of this work are: (1) to describe stereotactic helical tomotherapy processes (SRS, SBRT); (2) to show that the precision and accuracy of the HI-ART meet the requirements defined for SRS and SBRT; and (3) to describe the clinical implementation of a stereotactic image-guided intensity modulated radiation therapy (IG-IMRT) system that incorporates optical motion management

  12. Neoclassical current and plasma rotation in helical systems

    International Nuclear Information System (INIS)

    Nakajima, N.; Okamoto, M.

    1991-01-01

    In order to clarify geometrical effects of the magnetic field on the neoclassical theory in general toroidal systems, the neoclassical parallel particle flow, heat flux, current and plasma rotation of a multispecies plasma are examined using the moment approach on the basis of the original papers under the assumptions of no fluctuations, no external sources and losses except for a fast ion beam and an external inductive electric field, steady state, and |u a | Ta where u a and v Ta are the macro and thermal velocity of species a, respectively. Hence, we might have a point of view of unifying understanding the neoclassical theory in general toroidal systems. Three collisionality regimes, i.e., the 1/ν (in non-axisymmetric toroidal systems) or banana (in axisymmetric toroidal systems), plateau, and Pfirsch-Schlueter collisionality regimes are examined separately. (author) 8 refs

  13. Formation of positive radial electric field by electron cyclotron heating in compact helical system

    International Nuclear Information System (INIS)

    Idei, H.; Ida, K.; Sanuki, H.

    1994-07-01

    The radial electric field is driven to positive value by off-axis second harmonic electron cyclotron heating (ECH) in the Compact Helical System. The observed positive electric field is associated with the outward particle flux enhanced with ECH. The enhanced particle flux triggered by the production of the electrons accelerated perpendicularly to the magnetic field with ECH results in the change of the electric field. (author)

  14. Theoretical and experimental studies on electric field and confinement in helical systems

    International Nuclear Information System (INIS)

    Sanuki, H.; Itoh, K.; Todoroki, J.; Ida, K.; Idei, H.; Iguchi, H.; Yamada, H.

    1994-06-01

    The present study consists of two parts. The first part is oriented to a theoretical model of selfconsistent analysis to determine simultaneously the electric field and loss cone boundary in heliotron/torsatron configurations under the influence of nonclassical particle losses. The second part is referred to the analysis on NBI heated and ECH plasmas in Compact Helical System (CHS) device. A comparison is made between theoretical results and experimental observations. (author)

  15. Shielded helix traveling wave cathode ray tube deflection structure

    Science.gov (United States)

    Norris, N.J.; Hudson, C.L.

    1992-12-15

    Various embodiments of a helical coil deflection structure of a CRT are described and illustrated which provide shielding between adjacent turns of the coil on either three or four sides of each turn in the coil. Threaded members formed with either male or female threads and having the same pitch as the deflection coil are utilized for shielding the deflection coil with each turn of the helical coil placed between adjacent threads which act to shield each coil turn from adjacent turns and to confine the field generated by the coil to prevent or inhibit cross-coupling between adjacent turns of the coil to thereby prevent generation of fast fields which might otherwise deflect the beam out of time synchronization with the electron beam pulse. 13 figs.

  16. Helical Face Gear Development Under the Enhanced Rotorcraft Drive System Program

    Science.gov (United States)

    Heath, Gregory F.; Slaughter, Stephen C.; Fisher, David J.; Lewicki, David G.; Fetty, Jason

    2011-01-01

    U.S. Army goals for the Enhanced Rotorcraft Drive System Program are to achieve a 40 percent increase in horsepower to weight ratio, a 15 dB reduction in drive system generated noise, 30 percent reduction in drive system operating, support, and acquisition cost, and 75 percent automatic detection of critical mechanical component failures. Boeing s technology transition goals are that the operational endurance level of the helical face gearing and related split-torque designs be validated to a TRL 6, and that analytical and manufacturing tools be validated. Helical face gear technology is being developed in this project to augment, and transition into, a Boeing AH-64 Block III split-torque face gear main transmission stage, to yield increased power density and reduced noise. To date, helical face gear grinding development on Northstar s new face gear grinding machine and pattern-development tests at the NASA Glenn/U.S. Army Research Laboratory have been completed and are described.

  17. Helquats, helical extended diquats, as fast electron transfer systems

    Czech Academy of Sciences Publication Activity Database

    Pospíšil, Lubomír; Teplý, Filip; Gál, Miroslav; Adriaenssens, Louis; Horáček, Michal; Severa, Lukáš

    2010-01-01

    Roč. 12, č. 7 (2010), s. 1550-1556 ISSN 1463-9076 R&D Projects: GA ČR GA203/09/0705; GA ČR GP203/09/P502; GA MŠk ME09114; GA MŠk OC 140 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40550506 Keywords : reversible redox systems * self-exchange kinetics * methyl viologen Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.454, year: 2010

  18. Magnetic navigation system for the precise helical and translational motions of a microrobot in human blood vessels

    Science.gov (United States)

    Jeon, S. M.; Jang, G. H.; Choi, H. C.; Park, S. H.; Park, J. O.

    2012-04-01

    Different magnetic navigation systems (MNSs) have been investigated for the wireless manipulation of microrobots in human blood vessels. Here we propose a MNS and methodology for generation of both the precise helical and translational motions of a microrobot to improve its maneuverability in complex human blood vessel. We then present experiments demonstrating the helical and translational motions of a spiral-type microrobot to verify the proposed MNS.

  19. Confinement improvement in H-mode-like plasmas in helical systems

    International Nuclear Information System (INIS)

    Itoh, K.; Sanuki, H.; Itoh, S.; Fukuyama, A.; Yagi, M.

    1993-06-01

    The reduction of the anomalous transport due to the inhomogeneous radial electric field is theoretically studied for toroidal helical plasmas. The self-sustained interchange-mode turbulence is analysed for the system with magnetic shear and magnetic hill. For the system with magnetic well like conventional stellarators, the ballooning mode turbulence is studied. Influence of the radial electric field inhomogeneity on the transport coefficients and fluctuations are quantitatively shown. Unified theory of the transport coefficients in the L-mode and H-mode-like plasmas are presented. (author)

  20. Design and development of the helicity injection system in Versatile Experiment Spherical Torus

    International Nuclear Information System (INIS)

    Park, JongYoon; An, Younghwa; Jung, Bongki; Lee, Jeongwon; Lee, HyunYoung; Chung, Kyoung-Jae; Na, Yong-Su; Hwang, Y.S.

    2015-01-01

    Graphical abstract: - Highlights: • A high current electron gun with single pulse power for both arc and extraction is developed. • The optimal gun operation is confirmed by impedance matching between the PFN and plasma. • The gun injected currents of 0.95 kA with the voltage of ∼410 V for 5 ms with a 1.2 kV PFN. • The helicity injection system using the gun has been developed and tested successfully in VEST. • Toroidal currents of up to 3.8 kA confirm possible relaxation into tokamak-like plasma. - Abstract: A helicity injection system for the Versatile Experiment Spherical Torus (VEST) has been successfully developed and commissioned. A high current electron gun utilizing hollow cathode and washer stacks has been designed and constructed with a single pulse power system that can provide voltages for both arc discharge and extraction sequentially. Tests for electron gun operation with the single pulse power system have been conducted under various toroidal and poloidal field strengths. The estimated plasma impedance, depending on the injection magnetic field structure, can be utilized for the optimal gun operation by impedance matching between the pulse power system and plasma. With the charging voltage of 1.2 kV, injection current of 0.95 kA has been obtained with the injection voltage of 410 V for about 5 ms. Initial helicity injection experiments have been conducted under various toroidal and poloidal field strengths and a toroidal plasma current of up to 3.8 kA is observed with the current multiplication larger than the geometric stacking ratio, confirming the possibility of relaxation into tokamak-like plasma with closed flux formation.

  1. Design and development of the helicity injection system in Versatile Experiment Spherical Torus

    Energy Technology Data Exchange (ETDEWEB)

    Park, JongYoon; An, Younghwa; Jung, Bongki; Lee, Jeongwon; Lee, HyunYoung; Chung, Kyoung-Jae; Na, Yong-Su; Hwang, Y.S., E-mail: yhwang@snu.ac.kr

    2015-10-15

    Graphical abstract: - Highlights: • A high current electron gun with single pulse power for both arc and extraction is developed. • The optimal gun operation is confirmed by impedance matching between the PFN and plasma. • The gun injected currents of 0.95 kA with the voltage of ∼410 V for 5 ms with a 1.2 kV PFN. • The helicity injection system using the gun has been developed and tested successfully in VEST. • Toroidal currents of up to 3.8 kA confirm possible relaxation into tokamak-like plasma. - Abstract: A helicity injection system for the Versatile Experiment Spherical Torus (VEST) has been successfully developed and commissioned. A high current electron gun utilizing hollow cathode and washer stacks has been designed and constructed with a single pulse power system that can provide voltages for both arc discharge and extraction sequentially. Tests for electron gun operation with the single pulse power system have been conducted under various toroidal and poloidal field strengths. The estimated plasma impedance, depending on the injection magnetic field structure, can be utilized for the optimal gun operation by impedance matching between the pulse power system and plasma. With the charging voltage of 1.2 kV, injection current of 0.95 kA has been obtained with the injection voltage of 410 V for about 5 ms. Initial helicity injection experiments have been conducted under various toroidal and poloidal field strengths and a toroidal plasma current of up to 3.8 kA is observed with the current multiplication larger than the geometric stacking ratio, confirming the possibility of relaxation into tokamak-like plasma with closed flux formation.

  2. Stop Smoking—Tube-In-Tube Helical System for Flameless Calcination of Minerals

    Directory of Open Access Journals (Sweden)

    Nils Haneklaus

    2017-11-01

    Full Text Available Mineral calcination worldwide accounts for some 5–10% of all anthropogenic carbon dioxide (CO2 emissions per year. Roughly half of the CO2 released results from burning fossil fuels for heat generation, while the other half is a product of the calcination reaction itself. Traditionally, the fuel combustion process and the calcination reaction take place together to enhance heat transfer. Systems have been proposed that separate fuel combustion and calcination to allow for the sequestration of pure CO2 from the calcination reaction for later storage/use and capture of the combustion gases. This work presents a new tube-in-tube helical system for the calcination of minerals that can use different heat transfer fluids (HTFs, employed or foreseen in concentrated solar power (CSP plants. The system is labeled ‘flameless’ since the HTF can be heated by other means than burning fossil fuels. If CSP or high-temperature nuclear reactors are used, direct CO2 emissions can be divided in half. The technical feasibility of the system has been accessed with a brief parametric study here. The results suggest that the introduced system is technically feasible given the parameters (total heat transfer coefficients, mass- and volume flows, outer tube friction factors, and –Nusselt numbers that are examined. Further experimental work will be required to better understand the performance of the tube-in-tube helical system for the flameless calcination of minerals.

  3. Gear Design Effects on the Performance of High Speed Helical Gear Trains as Used in Aerospace Drive Systems

    Science.gov (United States)

    Handschuh, R.; Kilmain, C.; Ehinger, R.; Sinusas, E.

    2013-01-01

    The performance of high-speed helical gear trains is of particular importance for tiltrotor aircraft drive systems. These drive systems are used to provide speed reduction / torque multiplication from the gas turbine output shaft and provide the necessary offset between these parallel shafts in the aircraft. Four different design configurations have been tested in the NASA Glenn Research Center, High Speed Helical Gear Train Test Facility. The design configurations included the current aircraft design, current design with isotropic superfinished gear surfaces, double helical design (inward and outward pumping), increased pitch (finer teeth), and an increased helix angle. All designs were tested at multiple input shaft speeds (up to 15,000 rpm) and applied power (up to 5,000 hp). Also two lubrication, system-related, variables were tested: oil inlet temperature (160 to 250 degF) and lubricating jet pressure (60 to 80 psig). Experimental data recorded from these tests included power loss of the helical system under study, the temperature increase of the lubricant from inlet to outlet of the drive system and fling off temperatures (radially and axially). Also, all gear systems were tested with and without shrouds around the gears. The empirical data resulting from this study will be useful to the design of future helical gear train systems anticipated for next generation rotorcraft drive systems.

  4. Coupled lateral-torsional-axial vibrations of a helical gear-rotor-bearing system

    Science.gov (United States)

    Li, Chao-Feng; Zhou, Shi-Hua; Liu, Jie; Wen, Bang-Chun

    2014-10-01

    Considering the axial and radial loads, a mathematical model of angular contact ball bearing is deduced with Hertz contact theory. With the coupling effects of lateral, torsional and axial vibrations taken into account, a lumped-parameter nonlinear dynamic model of helical gearrotor-bearing system (HGRBS) is established to obtain the transmission system dynamic response to the changes of different parameters. The vibration differential equations of the drive system are derived through the Lagrange equation, which considers the kinetic and potential energies, the dissipative function and the internal/external excitation. Based on the Runge-Kutta numerical method, the dynamics of the HGRBS is investigated, which describes vibration properties of HGRBS more comprehensively. The results show that the vibration amplitudes have obvious fluctuation, and the frequency multiplication and random frequency components become increasingly obvious with changing rotational speed and eccentricity at gear and bearing positions. Axial vibration of the HGRBS also has some fluctuations. The bearing has self-variable stiffness frequency, which should be avoided in engineering design. In addition, the bearing clearance needs little attention due to its slightly discernible effect on vibration response. It is suggested that a careful examination should be made in modelling the nonlinear dynamic behavior of a helical gear-rotor-bearing system.

  5. Achieved capability of the superconducting magnet system for the large helical device

    International Nuclear Information System (INIS)

    Satow, T.; Imagawa, S.; Yanagi, N.

    2001-01-01

    The Large Helical Device (LHD) is a plasma physics experimental device with a magnetic stored energy of 960 MJ, consisting of two sc (superconducting) helical coils and six sc poloidal coils. The trial operation and the first plasma discharge of the eight-year Phase I project for LHD were finished on 31 March 1998 as initially planned. The second experimental campaign was conducted by additional heating using two NBI devices. The third campaign started in June 1999 and was finished in January 2000. Many plasma heating tests up to a plasma field of 2.90 T were carried out. Major test results on the sc magnet system for LHD are as follows: (1) The LHD cryogenic system succeeded in 13,400-hour operation and proved its high reliability. (2) A central field of 2.91 T at a radius of 3.60 m was achieved at an H-I current of 11.08 kA, H-M current of 11.83 kA and an H-O current of 12.02 kA. (3) All six poloidal coils were excited stably. (4) Nine flexible sc bus-lines with a total length of 497 m were operated stably and safe. (author)

  6. Technical Note: Output and energy fluctuations of the tomotherapy Hi-Art helical tomotherapy system

    International Nuclear Information System (INIS)

    Mahan, Stephen L.; Chase, Daniel J.; Ramsey, Chester R.

    2004-01-01

    The output and energy calibrations for the first clinical Hi-Art 2.0 helical tomotherapy system have been reviewed. Fixed-gantry/fixed-couch and rotational-gantry/fixed-couch measurements were made on a daily basis over a period of 20 weeks to investigate system stability. Static gantry measurements were taken at 10 cm depth in a rectangular stack of Virtual Water at an SSD distance of 90 cm and a field size of 5x40 cm. Rotational gantry measurements were taken in a cylindrical phantom Virtual Water phantom for a field size of 5x40 cm. The Hi-Art 2.0 system has maintained its calibration to within ±2% and energy to within ±1.5% over the initial 20 week period

  7. Clinical benefits of new immobilization system for hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma by helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yong; Zhou, Yong-Kang; Chen, Yi-Xing; Shi, Shi-Ming; Zeng, Zhao-Chong, E-mail: zeng.zhaochong@zs-hospital.sh.cn

    2017-04-01

    Objective: A comprehensive clinical evaluation was conducted, assessing the Body Pro-Lok immobilization and positioning system to facilitate hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma (HCC), using helical tomotherapy to improve treatment precision. Methods: Clinical applications of the Body Pro-Lok system were investigated (as above) in terms of interfractional and intrafractional setup errors and compressive abdominal breath control. To assess interfractional setup errors, a total of 42 patients who were given 5 to 20 fractions of helical tomotherapy for intrahepatic HCC were analyzed. Overall, 15 patients were immobilized using simple vacuum cushion (group A), and the Body Pro-Lok system was used in 27 patients (group B), performing megavoltage computed tomography (MVCT) scans 196 times and 435 times, respectively. Pretreatment MVCT scans were registered to the planning kilovoltage computed tomography (KVCT) for error determination, and group comparisons were made. To establish intrafractional setup errors, 17 patients with intrahepatic HCC were selected at random for immobilization by Body Pro-Lok system, undergoing MVCT scans after helical tomotherapy every week. A total of 46 MVCT re-scans were analyzed for this purpose. In researching breath control, 12 patients, randomly selected, were immobilized by Body Pro-Lok system and subjected to 2-phase 4-dimensional CT (4DCT) scans, with compressive abdominal control or in freely breathing states, respectively. Respiratory-induced liver motion was then compared. Results: Mean interfractional setup errors were as follows: (1) group A: X, 2.97 ± 2.47 mm; Y, 4.85 ± 4.04 mm; and Z, 3.77 ± 3.21 mm; pitch, 0.66 ± 0.62°; roll, 1.09 ± 1.06°; and yaw, 0.85 ± 0.82°; and (2) group B: X, 2.23 ± 1.79 mm; Y, 4.10 ± 3.36 mm; and Z, 1.67 ± 1.91 mm; pitch, 0.45 ± 0.38°; roll, 0.77 ± 0.63°; and yaw, 0.52 ± 0.49°. Between-group differences were statistically significant in 6 directions (p

  8. Clinical benefits of new immobilization system for hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma by helical tomotherapy

    International Nuclear Information System (INIS)

    Hu, Yong; Zhou, Yong-Kang; Chen, Yi-Xing; Shi, Shi-Ming; Zeng, Zhao-Chong

    2017-01-01

    Objective: A comprehensive clinical evaluation was conducted, assessing the Body Pro-Lok immobilization and positioning system to facilitate hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma (HCC), using helical tomotherapy to improve treatment precision. Methods: Clinical applications of the Body Pro-Lok system were investigated (as above) in terms of interfractional and intrafractional setup errors and compressive abdominal breath control. To assess interfractional setup errors, a total of 42 patients who were given 5 to 20 fractions of helical tomotherapy for intrahepatic HCC were analyzed. Overall, 15 patients were immobilized using simple vacuum cushion (group A), and the Body Pro-Lok system was used in 27 patients (group B), performing megavoltage computed tomography (MVCT) scans 196 times and 435 times, respectively. Pretreatment MVCT scans were registered to the planning kilovoltage computed tomography (KVCT) for error determination, and group comparisons were made. To establish intrafractional setup errors, 17 patients with intrahepatic HCC were selected at random for immobilization by Body Pro-Lok system, undergoing MVCT scans after helical tomotherapy every week. A total of 46 MVCT re-scans were analyzed for this purpose. In researching breath control, 12 patients, randomly selected, were immobilized by Body Pro-Lok system and subjected to 2-phase 4-dimensional CT (4DCT) scans, with compressive abdominal control or in freely breathing states, respectively. Respiratory-induced liver motion was then compared. Results: Mean interfractional setup errors were as follows: (1) group A: X, 2.97 ± 2.47 mm; Y, 4.85 ± 4.04 mm; and Z, 3.77 ± 3.21 mm; pitch, 0.66 ± 0.62°; roll, 1.09 ± 1.06°; and yaw, 0.85 ± 0.82°; and (2) group B: X, 2.23 ± 1.79 mm; Y, 4.10 ± 3.36 mm; and Z, 1.67 ± 1.91 mm; pitch, 0.45 ± 0.38°; roll, 0.77 ± 0.63°; and yaw, 0.52 ± 0.49°. Between-group differences were statistically significant in 6 directions (p

  9. Positively deflected anomaly mediation

    International Nuclear Information System (INIS)

    Okada, Nobuchika

    2002-01-01

    We generalize the so-called 'deflected anomaly mediation' scenario to the case where threshold corrections of heavy messengers to the sparticle squared masses are positive. A concrete model realizing this scenario is also presented. The tachyonic slepton problem can be fixed with only a pair of messengers. The resultant sparticle mass spectrum is quite different from that in the conventional deflected anomaly mediation scenario, but is similar to the one in the gauge mediation scenario. The lightest sparticle is mostly B-ino

  10. Computer-aided diagnosis workstation and database system for chest diagnosis based on multi-helical CT images

    Science.gov (United States)

    Satoh, Hitoshi; Niki, Noboru; Mori, Kiyoshi; Eguchi, Kenji; Kaneko, Masahiro; Kakinuma, Ryutarou; Moriyama, Noriyuki; Ohmatsu, Hironobu; Masuda, Hideo; Machida, Suguru; Sasagawa, Michizou

    2006-03-01

    Multi-helical CT scanner advanced remarkably at the speed at which the chest CT images were acquired for mass screening. Mass screening based on multi-helical CT images requires a considerable number of images to be read. It is this time-consuming step that makes the use of helical CT for mass screening impractical at present. To overcome this problem, we have provided diagnostic assistance methods to medical screening specialists by developing a lung cancer screening algorithm that automatically detects suspected lung cancers in helical CT images and a coronary artery calcification screening algorithm that automatically detects suspected coronary artery calcification. We also have developed electronic medical recording system and prototype internet system for the community health in two or more regions by using the Virtual Private Network router and Biometric fingerprint authentication system and Biometric face authentication system for safety of medical information. Based on these diagnostic assistance methods, we have now developed a new computer-aided workstation and database that can display suspected lesions three-dimensionally in a short time. This paper describes basic studies that have been conducted to evaluate this new system. The results of this study indicate that our computer-aided diagnosis workstation and network system can increase diagnostic speed, diagnostic accuracy and safety of medical information.

  11. Study of an edge transport barrier by Langmuir probes in the compact helical system

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, M [Department of Energy Engineering and Science, Nagoya University, Nagoya 464-8603 (Japan); Toi, K [National Institute of Fusion Science, Toki 509-5292 (Japan); Nagaoka, K [National Institute of Fusion Science, Toki 509-5292 (Japan); Suzuki, C [National Institute of Fusion Science, Toki 509-5292 (Japan); Minami, T [National Institute of Fusion Science, Toki 509-5292 (Japan); Akiyama, T [National Institute of Fusion Science, Toki 509-5292 (Japan); Isobe, M [National Institute of Fusion Science, Toki 509-5292 (Japan); Yoshimura, Y [National Institute of Fusion Science, Toki 509-5292 (Japan); Nishimura, S [National Institute of Fusion Science, Toki 509-5292 (Japan); Shimizu, A [National Institute of Fusion Science, Toki 509-5292 (Japan); Takahashi, C [National Institute of Fusion Science, Toki 509-5292 (Japan); Matsuoka, K [National Institute of Fusion Science, Toki 509-5292 (Japan); Okamura, S [National Institute of Fusion Science, Toki 509-5292 (Japan)

    2006-05-15

    The edge transport barrier (ETB) produced by the L-H transition was measured by a triple Langmuir probe (LP) at two toroidal sections of the compact helical system (CHS), of which diagnostic method has good time and spatial resolutions. The radial profiles of electron density (n{sub e}), electron temperature (T{sub e}) and space potential (V{sub s}) in the ETB region have different shapes at two different toroidal sections. These profiles are deformed inside the ETB region at one location and are formed with rather smooth variations at the other. These deformations gradually disappear in the deep H-phase (after {approx}15 ms from the transition) and the profiles inside the ETB become similar at both sections. The deformation seems linked to the presence of a non-rotating magnetic island at the rational surface of the rotational transform {iota}/2{pi} = 1.

  12. Electron cyclotron emission from optically thin plasma in compact helical system

    International Nuclear Information System (INIS)

    Idei, Hiroshi; Kubo, Shin; Hosokawa, Minoru; Iguchi, Harukazu; Ohkubo, Kunizo; Sato, Teruyuki.

    1994-01-01

    A frequency spectrum of second harmonic electron cyclotron emission was observed for an optically thin plasma produced by fundamental electron cyclotron heating in a compact helical system. A radial electron temperature profile deduced from this spectrum neglecting the multiple reflections effect shows a clear difference from that measured by Thomson scattering. We relate the spectrum with the electron temperature profile by the modified emission model including the scrambling effect. The scrambling effect results from both mode conversion and change in the trajectory due to multiple reflections of the emitting ray at the vessel wall. The difference between the two temperature profiles is explained well by using the modified emission model. Reconstruction of the electron temperature profile from the spectrum using this model is also discussed. (author)

  13. Dynamic analysis of compact helical system power supply and designs of its upgrade

    International Nuclear Information System (INIS)

    Tanahashi, S.; Yamada, S.

    1991-09-01

    Computed dynamic waveforms are compared with measured ones for the power supply of the Compact Helical System (CHS) during 1.5T operation and found to be in good agreement. On the basis of these results, designs for the upgraded power supply for 2T operation are discussed in the two cases, with and without power consumption for additional heating. In the former case, the additional heating power is supplied from the ac generator that powers the CHS coils. Electric voltages and currents in the electric circuit are shown for both cases. These designs show the possibility for 2T operation by addition of some components without changing the ratings of existing components. (author)

  14. Proposed high speed pellet injection system 'HIPEL' for Large Helical Device

    International Nuclear Information System (INIS)

    Sudo, S.; Kanno, M.; Kaneko, H.; Saka, S.; Shirai, T.; Baba, T.

    1993-11-01

    From the results of the simulation study including pellet ablation and 1-D transport code, it is found that a high speed pellet injector with pellet velocity of more than 3 km/s is necessary for the penetration of the pellet with diameter of 3 mm into the core region under the expected plasma condition of Large Helical Device (LHD) of heliotron/stellarator type with superconducting coils at NIFS in Japan. Therefore, a two stage pellet injector was constructed and tested successfully in order to obtain the pellet velocity range of 3 km/s. Based upon the above results, a high speed flexible multiple-pellet injection system 'HIPEL' for LHD is proposed. HIPEL consists of independent (1) 10 two-stage gun barrels and (2) 10 single-stage gun barrels. It has multi purposes such as refueling and flexible density profile control, diagnostics and the other functions. (author)

  15. Conceptual design of the cryogenic system for the helical-type fusion power plant FFHR

    International Nuclear Information System (INIS)

    Yamada, S.; Sagara, A.; Imagawa, S.; Mito, T.; Motojima, O.

    2007-01-01

    The force-free helical-type fusion reactor, FFHR, is proposed on the basis of the engineering achievements and confinement properties of the experimental fusion device of LHD. The outputs of the thermal power and electric power are optimized to 3 and 1 GW, respectively. Total weight of the superconducting (SC) coils and their supporting structures of the FFHR are estimated to be 18,000 t. An equivalent refrigeration capacity of 98 kW is necessary for coping with different plant loads. Mass-flow rate of the main circulation compressors is 9.5 kg/s and their power consumption is 29 MW. The FFHR is used for the co-generation system of electricity and hydrogen. The pressurized hydrogen of 100 t per day can be produced, when the stem electrolyzer of 150 MW class is applied. Electric power consumption of the hydrogen liquefaction with 100 t per day is estimated to be 26 MW

  16. Space potential fluctuations during MHD activities in the Compact Helical System (CHS)

    International Nuclear Information System (INIS)

    Iguchi, H.; Fujisawa, A.; Crowley, T.P.

    1998-02-01

    Local space potential fluctuations have been measured during MHD activities in a low-beta NBI heated plasma in the Compact Helical System (CHS) by the use of a heavy ion beam probe (HIBP). Two types of MHD modes with accompanying potential oscillations are observed. One appears in periodic bursts with relatively low frequency (< 40 kHz) and large amplitude (20-40 volts), and is localized around the q=2 surface (average minor radius ρ ∼ 0.7). The other appears in continuous and coherent oscillation with higher frequency (105-125 kHz) and smaller amplitude (∼5 volts). This oscillation also has spatial structure. Possible interpretation for the space potential oscillations is presented. (author)

  17. Beam-driven currents in the 1/ν regime in a helical system

    International Nuclear Information System (INIS)

    Nakajima, Noriyoshi; Okamoto, Masao.

    1990-04-01

    Beam currents driven by a neutral particle injection in a helical system (stellarator, heliotron/torsatron) are studied in the 1/ν collisionality regime. The general expression for the beam-driven current is obtained for arbitrary magnetic field configurations by solving the drift kinetic equation for electrons. It is found that F = J(net)/J(b) (J(net) is the net current and J(b) is the fast ion beam current) increases as f(t) and Zeff where f(t) is the fraction of trapped electrons and Zeff is the effective ionic charge number. Especially, for Zeff ≅ 1 the effect of trapped electrons is large and F is roughly proportional to f(t). On the other hand, if Zeff > or approx 3 the effect of trapped electrons becomes small. (author)

  18. High β experiment and confinement regimes in a compact helical system

    International Nuclear Information System (INIS)

    Matsuoka, K.; Okamura, S.; Nishimura, K.; Tsumori, K.; Akiyama, R.; Yamada, H.; Sakakibara, S.; Lazaros, A.; Xu, J.; Ida, K.; Tanaka, K.; Morisaki, T.; Morita, S.; Arimoto, H.; Fujiwara, M.; Idei, H.; Iguchi, H.; Kaneko, O.; Kawamoto, T.; Kubo, S.; Kuroda, T.; Motojima, O.; Ozaki, T.; Pustovitov, V.D.; Sagara, A.; Takahashi, C.; Toi, K.; Watari, T.; Yamada, I.

    1995-01-01

    A volume-averaged equilibrium β value left angle β eq right angle of 2.14% is achieved in a compact helical system using two neutral beam lines with balanced injection and intense wall conditioning with Ti gettering. This value is the highest β value realized so far in helical systems. Reheat mode, where the stored energy increases after turn-off of a strong gas puff, is employed in the experiment. Discharge conditions are as follows: B t =0.61T; beam power through the port, 1.1MW (coinjection) and 0.8MW (counterinjection); line-averaged electron density n e =6.5x10 13 cm -3 . Amplitudes of magnetic fluctuations integrated over the frequency range from 3kHz to 100kHz become saturated at left angle β eq right angle higher than 1%. Dominant coherent modes are m/n=2/1 and 1/1 when left angle β eq right angle is lower and higher respectively than 1%. Dependence of the energy confinement time τ E on n e (up to 8x10 13 cm -3 ) and B t (from 0.6 to 1.8T) is also studied in this high β experiment. When the density increases τ E degrades compared with the LHD scaling; the density dependence exhibits Bohm-like behaviour. On the contrary, τ E scales as B ∼0.75 t , which is rather close to the LHD scaling (gyro-Bohm-like behaviour). ((orig.))

  19. Deflection control system for prestressed concrete bridges by CCD camera. CCD camera ni yoru prestressed concrete kyo no tawami kanri system

    Energy Technology Data Exchange (ETDEWEB)

    Noda, Y.; Nakayama, Y.; Arai, T. (Kawada Construction Co. Ltd., Tokyo (Japan))

    1994-03-15

    For the long-span prestressed concrete bridge (continuous box girder and cable stayed bridge), the design and construction control becomes increasingly complicated as construction proceeds because of its cyclic works. This paper describes the method and operation of an automatic levelling module using CCD camera and the experimental results by this system. For this automatic levelling system, the altitude can be automatically measured by measuring the center location of gravity of the target on the bridge surface using CCD camera. The present deflection control system developed compares the measured value by the automatic levelling system with the design value obtained by the design calculation system, and manages them. From the real-time continuous measurement for the long term, in which the CCD camera was set on the bridge surface, it was found that the stable measurement accuracy can be obtained. Successful application of this system demonstrates that the system is an effective and efficient construction aid. 11 refs., 19 figs., 1 tab.

  20. Remote control of Alfven eigenmode sensing system on the large helical device

    Energy Technology Data Exchange (ETDEWEB)

    Ito, T. [Nagoya University, Department of Energy Engineering and Science, Furo-cho, Chikusa-ku, Nagoya City, Aichi (Japan)], E-mail: ito.takafumi@lhd.nifs.ac.jp; Toi, K. [Nagoya University, Department of Energy Engineering and Science, Furo-cho, Chikusa-ku, Nagoya City, Aichi (Japan); National Institute for Fusion Science, 322-6 Oroshicho, Toki, Gifu (Japan); Matsunaga, G. [Japan Atomic Energy Agency, 801-1 Mukouyama, Naka, Ibaraki 311-0193 (Japan)

    2008-04-15

    An active sensing system of Alfven eigenmodes (AEs), which consists of a set of toroidally distributed loop antennas and several bi-polar power supplies, has been developed in the large helical device (LHD). The power supplies are controlled with a function generator receiving a control pattern of antenna current and the driving frequency from a personal computer (PC) in an LHD control room. This sensing method is based on the analysis of the frequency dependence of a transfer function that is derived by the ratio of the Fourier-transformed magnetic probe signal ('plasma response') to antenna current one ('exciter signal'). Typically, the driving frequency of the antenna current is swept linearly in time from 10 kHz to 500 kHz for 2 s in the LHD experiment. The sensing system is fully controlled through Ethernet LAN with easy extendable GUI. Configuration and control scheme of the active sensing system of AEs are presented in this paper. An initial result of the system operation is also described.

  1. Remote control of Alfven eigenmode sensing system on the large helical device

    International Nuclear Information System (INIS)

    Ito, T.; Toi, K.; Matsunaga, G.

    2008-01-01

    An active sensing system of Alfven eigenmodes (AEs), which consists of a set of toroidally distributed loop antennas and several bi-polar power supplies, has been developed in the large helical device (LHD). The power supplies are controlled with a function generator receiving a control pattern of antenna current and the driving frequency from a personal computer (PC) in an LHD control room. This sensing method is based on the analysis of the frequency dependence of a transfer function that is derived by the ratio of the Fourier-transformed magnetic probe signal ('plasma response') to antenna current one ('exciter signal'). Typically, the driving frequency of the antenna current is swept linearly in time from 10 kHz to 500 kHz for 2 s in the LHD experiment. The sensing system is fully controlled through Ethernet LAN with easy extendable GUI. Configuration and control scheme of the active sensing system of AEs are presented in this paper. An initial result of the system operation is also described

  2. A small-animal imaging system capable of multipinhole circular/helical SPECT and parallel-hole SPECT

    International Nuclear Information System (INIS)

    Qian Jianguo; Bradley, Eric L.; Majewski, Stan; Popov, Vladimir; Saha, Margaret S.; Smith, Mark F.; Weisenberger, Andrew G.; Welsh, Robert E.

    2008-01-01

    We have designed and built a small-animal single-photon emission computed tomography (SPECT) imaging system equipped with parallel-hole and multipinhole collimators and capable of circular or helical SPECT. Copper-beryllium parallel-hole collimators suitable for imaging the ∼35 keV photons from the decay of 125 I have been built and installed to achieve useful spatial resolution over a range of object-detector distances and to reduce imaging time on our dual-detector array. To address the resolution limitations in the parallel-hole SPECT and the sensitivity and limited field of view of single-pinhole SPECT, we have incorporated multipinhole circular and helical SPECT in addition to expanding the parallel-hole SPECT capabilities. The pinhole SPECT system is based on a 110 mm diameter circular detector equipped with a pixellated NaI(Tl) scintillator array (1x1x5 mm 3 /pixel). The helical trajectory is accomplished by two stepping motors controlling the rotation of the detector-support gantry and displacement of the animal bed along the axis of rotation of the gantry. Results obtained in SPECT studies of various phantoms show an enlarged field of view, very good resolution and improved sensitivity using multipinhole circular or helical SPECT. Collimators with one, three and five, 1-mm-diameter pinholes have been implemented and compared in these tests. Our objective is to develop a system on which one may readily select a suitable mode of either parallel-hole SPECT or pinhole circular or helical SPECT for a variety of small animal imaging applications

  3. Independent calculation of dose distributions for helical tomotherapy using a conventional treatment planning system

    Energy Technology Data Exchange (ETDEWEB)

    Klüter, Sebastian, E-mail: sebastian.klueter@med.uni-heidelberg.de; Schubert, Kai; Lissner, Steffen; Sterzing, Florian; Oetzel, Dieter; Debus, Jürgen [Department of Radiation Oncology, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany, and Heidelberg Institute for Radiation Oncology (HIRO), Im Neuenheimer Feld 400, 69120 Heidelberg, Germany, and German Consortium for Translational Cancer Research (DKTK), Im Neuenheimer Feld 400, 69120 Heidelberg (Germany); Schlegel, Wolfgang [German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Oelfke, Uwe [German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG (United Kingdom); Nill, Simeon [Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG (United Kingdom)

    2014-08-15

    Purpose: The dosimetric verification of treatment plans in helical tomotherapy usually is carried out via verification measurements. In this study, a method for independent dose calculation of tomotherapy treatment plans is presented, that uses a conventional treatment planning system with a pencil kernel dose calculation algorithm for generation of verification dose distributions based on patient CT data. Methods: A pencil beam algorithm that directly uses measured beam data was configured for dose calculation for a tomotherapy machine. Tomotherapy treatment plans were converted into a format readable by an in-house treatment planning system by assigning each projection to one static treatment field and shifting the calculation isocenter for each field in order to account for the couch movement. The modulation of the fluence for each projection is read out of the delivery sinogram, and with the kernel-based dose calculation, this information can directly be used for dose calculation without the need for decomposition of the sinogram. The sinogram values are only corrected for leaf output and leaf latency. Using the converted treatment plans, dose was recalculated with the independent treatment planning system. Multiple treatment plans ranging from simple static fields to real patient treatment plans were calculated using the new approach and either compared to actual measurements or the 3D dose distribution calculated by the tomotherapy treatment planning system. In addition, dose–volume histograms were calculated for the patient plans. Results: Except for minor deviations at the maximum field size, the pencil beam dose calculation for static beams agreed with measurements in a water tank within 2%/2 mm. A mean deviation to point dose measurements in the cheese phantom of 0.89% ± 0.81% was found for unmodulated helical plans. A mean voxel-based deviation of −0.67% ± 1.11% for all voxels in the respective high dose region (dose values >80%), and a mean local

  4. Independent calculation of dose distributions for helical tomotherapy using a conventional treatment planning system

    International Nuclear Information System (INIS)

    Klüter, Sebastian; Schubert, Kai; Lissner, Steffen; Sterzing, Florian; Oetzel, Dieter; Debus, Jürgen; Schlegel, Wolfgang; Oelfke, Uwe; Nill, Simeon

    2014-01-01

    Purpose: The dosimetric verification of treatment plans in helical tomotherapy usually is carried out via verification measurements. In this study, a method for independent dose calculation of tomotherapy treatment plans is presented, that uses a conventional treatment planning system with a pencil kernel dose calculation algorithm for generation of verification dose distributions based on patient CT data. Methods: A pencil beam algorithm that directly uses measured beam data was configured for dose calculation for a tomotherapy machine. Tomotherapy treatment plans were converted into a format readable by an in-house treatment planning system by assigning each projection to one static treatment field and shifting the calculation isocenter for each field in order to account for the couch movement. The modulation of the fluence for each projection is read out of the delivery sinogram, and with the kernel-based dose calculation, this information can directly be used for dose calculation without the need for decomposition of the sinogram. The sinogram values are only corrected for leaf output and leaf latency. Using the converted treatment plans, dose was recalculated with the independent treatment planning system. Multiple treatment plans ranging from simple static fields to real patient treatment plans were calculated using the new approach and either compared to actual measurements or the 3D dose distribution calculated by the tomotherapy treatment planning system. In addition, dose–volume histograms were calculated for the patient plans. Results: Except for minor deviations at the maximum field size, the pencil beam dose calculation for static beams agreed with measurements in a water tank within 2%/2 mm. A mean deviation to point dose measurements in the cheese phantom of 0.89% ± 0.81% was found for unmodulated helical plans. A mean voxel-based deviation of −0.67% ± 1.11% for all voxels in the respective high dose region (dose values >80%), and a mean local

  5. Short-term and long-term deflection of reinforced hollow core ...

    African Journals Online (AJOL)

    This paper presents a study on different methods of analysis that are currently used by design codes to predict the short-term and long-term deflection of reinforced concrete slab systems and compares the predicted deflections with measured deflections. The experimental work to measure deflections involved the testing of ...

  6. Monte-Carlo calculation of perpendicular neutral-beam injection in helical systems

    International Nuclear Information System (INIS)

    Hanatani, K.; Wakatani, M.; Uo, K.

    1981-01-01

    The effect of a helical field ripple on the slowing-down process of the fast ions created by neutral injection is investigated numerically. For this purpose, the guiding-centre orbits are followed in a model magnetic field without plasma current, on the assumption that the slowing-down process is to be classical. Optimum injection angles in two types of helical magnetic traps are compared. One is the Heliotron-E configuration with a large rotational transform and deep helical ripple; the other one is the conventional stellarator field with a small rotational transform and shallow helical ripple. In contrast to the stellarator, the heating efficiency as calculated for Heliotron-E does not decrease monotonically when the injection angle is perpendicular to the toroidal direction; a heating efficiency of above 70% was obtained for perpendicular injection into a high-density plasma with negligible charge-exchange loss. The difference in heating efficiency versus injection angle between heliotron and conventional stellarator fields is explained by a difference in drift motion of the helically trapped fast ions. (author)

  7. Calibration of optical cantilever deflection readers

    International Nuclear Information System (INIS)

    Hu Zhiyu; Seeley, Tim; Kossek, Sebastian; Thundat, Thomas

    2004-01-01

    Because of its ultrahigh sensitivity, the optical lever detection method similar to that used in the atomic force microscope (AFM) has been widely employed as a standard technique for measuring microcantilever deflection. Along with the increasing interest in using the microcantilever as a sensing platform, there is also a requirement for a reliable calibration technique. Many researchers have used the concept of optical lever detection to construct microcantilever deflection readout instruments for chemical, physical, and biological detection. However, without an AFM piezo z scanner, it is very difficult to precisely calibrate these instruments. Here, we present a step-by-step method to conveniently calibrate an instrument using commercially available piezoresistive cantilevers. The experimental results closely match the theoretical calculation. Following this procedure, one can easily calibrate any optical cantilever deflection detection system with high reproducibility, precision, and reliability. A detailed discussion of the optical lever readout system design has been addressed in this article

  8. Performances of solar water pumping system using helical pump for a deep well: A case study for Madinah, Saudi Arabia

    International Nuclear Information System (INIS)

    Benghanem, M.; Daffallah, K.O.; Joraid, A.A.; Alamri, S.N.; Jaber, A.

    2013-01-01

    Highlights: ► The best performance of helical pump has been reached for a deep well. ► Very high potential of solar energy at Saudi Arabia. ► Performance of solar water pumping system for a deep well of 120 m. ► We get the best efficiency of helical pump for the head of 80 m. ► The best configuration of PV generator (24 panels) has been obtained. - Abstract: The photovoltaic water pumping systems (PVWPS) constitute a potential option to draw down water in the remote desert locations for domestic usage and livestock watering. However, the widespread of this technique requires accurate information and experiences in such system sizing and installation. The aim of this work is to determine an optimum photovoltaic (PV) array configuration, adequate to supply a DC Helical pump with an optimum energy amount, under the outdoor conditions of Madinah site. Four different PV array configurations have been tested (6S × 3P, 6S × 4P, 8S × 3P and 12S × 2P). The tests have been carried for a head of 80 m, under sunny daylight hours, in a real well at a farm in Madinah site. The best results have been obtained for two PV array configurations (6S × 4P) and (8S × 3P) which are suitable to provide the optimum energy. Powered by the selected PV array configurations, the helical pump (SQF2.5-2) delivered a maximum daily average volume of water needed (22 m 3 /day).

  9. Functional performance of the helical coil steam generator, Consolidated Nuclear Steam Generator (CNSG) IV system. Executive summary report

    International Nuclear Information System (INIS)

    Watson, G.B.

    1975-10-01

    The objective of this project was to study the functional performance of the CNSG - IV helical steam generator to demonstrate that the generator meets steady-state and transient thermal-hydraulic performance specifications and that secondary flow instability will not be a problem. Economic success of the CNSG concepts depends to a great extent on minimizing the size of the steam generator and the reactor vessel for ship installation. Also, for marine application the system must meet stringent specifications for operating stability, transient response, and control. The full-size two-tube experimental unit differed from the CNSG only in the number of tubes and the mode of primary flow. In general, the functional performance test demonstrated that the helical steam generator concept will exceed the specified superheat of 35F at 100% load. The experimental measured superheat at comparable operating conditions was 95F. Testing also revealed that available computer codes accurately predict trends and overall performance characteristics

  10. Computerized ultrasonic quality control system in the production of helical welded tubes

    International Nuclear Information System (INIS)

    Tar, J.

    1976-01-01

    The inspection of helical welded steel tubes by means of an ultrasonic automatic equipment is described. This equipment is able to recognize the defects of the weld, to identify them and to continuously report back the informations necessary for their elimination

  11. Ergodization of magnetic surfaces due to finite beta effect in a helical system

    International Nuclear Information System (INIS)

    Hayashi, Takaya.

    1989-04-01

    Breaking of magnetic surfaces due to finite beta effect in a l=2 heliotron/torsatron configuration is studied by using a newly developed three dimensional equilibrium code. Breaking can be suppressed by a larger aspect ratio configuration, shaping of magnetic surface (inward shift or prolate shape), pitch modulation of helical coils, or pressure profile control. (author)

  12. Helical filaments

    Energy Technology Data Exchange (ETDEWEB)

    Barbieri, Nicholas; Lim, Khan; Durand, Magali; Baudelet, Matthieu; Richardson, Martin [Townes Laser Institute, CREOL—The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Hosseinimakarem, Zahra; Johnson, Eric [Micro-Photonics Laboratory – Center for Optical Material Science, Clemson, Anderson, South Carolina 29634 (United States)

    2014-06-30

    The shaping of laser-induced filamenting plasma channels into helical structures by guiding the process with a non-diffracting beam is demonstrated. This was achieved using a Bessel beam superposition to control the phase of an ultrafast laser beam possessing intensities sufficient to induce Kerr effect driven non-linear self-focusing. Several experimental methods were used to characterize the resulting beams and confirm the observed structures are laser air filaments.

  13. Flow deflection over a foredune

    Science.gov (United States)

    Hesp, Patrick A.; Smyth, Thomas A. G.; Nielsen, Peter; Walker, Ian J.; Bauer, Bernard O.; Davidson-Arnott, Robin

    2015-02-01

    Flow deflection of surface winds is common across coastal foredunes and blowouts. Incident winds approaching obliquely to the dune toe and crestline tend to be deflected towards a more crest-normal orientation across the stoss slope of the foredune. This paper examines field measurements for obliquely incident winds, and compares them to computational fluid dynamics (CFD) modelling of flow deflection in 10° increments from onshore (0°) to alongshore (90°) wind approach angles. The mechanics of flow deflection are discussed, followed by a comparative analysis of measured and modelled flow deflection data that shows strong agreement. CFD modelling of the full range of onshore to alongshore incident winds reveals that deflection of the incident wind flow is minimal at 0° and gradually increases as the incident wind turns towards 30° to the dune crest. The greatest deflection occurs between 30° and 70° incident to the dune crest. The degree of flow deflection depends secondarily on height above the dune surface, with the greatest effect near the surface and toward the dune crest. Topographically forced flow acceleration ("speed-up") across the stoss slope of the foredune is greatest for winds less than 30° (i.e., roughly perpendicular) and declines significantly for winds with more oblique approach angles. There is less lateral uniformity in the wind field when the incident wind approaches from > 60° because the effect of aspect ratio on topographic forcing and streamline convergence is less pronounced.

  14. Geometric formula for prism deflection

    Indian Academy of Sciences (India)

    , governs deflections produced by prisms of refractive index n. The refractive power, n − 1, of most materials is of the order of unity for visible light, which therefore gets deflected through several degrees by a prism. X-rays and neutrons however ...

  15. Radiation profile measurements for edge transport barrier discharges in Compact Helical System using AXUV photodiode arrays

    International Nuclear Information System (INIS)

    Suzuki, C.; Okamura, S.; Minami, T.; Akiyama, T.; Fujisawa, A.; Ida, K.; Isobe, M.; Matsuoka, K.; Nagaoka, K.; Nishimura, S.; Peterson, B. J.; Shimizu, A.; Takahashi, C.; Toi, K.; Yoshimura, Y.

    2005-01-01

    The formation of edge transport barrier (ETB) has recently been found in Compact Helical System (CHS) plasmas heated by co-injected neutral beam injection (NBI) with strong gas puffing. This regime is characterized by the appearance of the steep gradient of the electron density near the edge following the abrupt drop of hydrogen Balmer alpha (H α ) line intensity. In addition to single channel pyroelectric detector as a conventional bolometer, we have employed unfiltered absolute extreme ultraviolet (AXUV) photodiode arrays as a simple and low-cost diagnostic to investigate spatial and temporal variations of radiation emissivity in the ETB discharges. A compact mounting module for a 20 channel AXUV photodiode array including an in-vacuum preamplifier for immediate current-voltage conversion has successfully been designed and fabricated. Two identical modules installed in the upper and lower viewports provide 40 lines of sight covering the inboard and outboard sides within the horizontally elongated cross section of the CHS plasma with wide viewing angle. Although spectral uniformity of the detector sensitivity of the AXUV photodiode is unsatisfied for photon energies lower than 200 eV, it has been confirmed that the signals of AXUV photodiode and pyroelectric detector in the ETB discharges show roughly the same behavior except for the very beginning and end of the discharges. The results of the measurements in typical ETB discharges show that the signals of all the channels of the AXUV photodiode arrays begin to increase more rapidly at the moment of the transition than before. The rate of the increase is larger for the edge viewing chords than for the center viewing ones, which indicates the flattening of the radiation profile following the change in the electron density profile after the formation of the ETB. However, the signals for the edge chords tend to saturate after several tens of milliseconds, while they still continue to increase for the central chords

  16. Impacts of Deflection Nose on Ballistic Trajectory Control Law

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2014-01-01

    Full Text Available The deflection of projectile nose is aimed at changing the motion of the projectile in flight with the theory of motion control and changing the exterior ballistics so as to change its range and increase its accuracy. The law of external ballistics with the deflectable nose is considered as the basis of the design of a flight control system and an important part in the process of projectile development. Based on the existing rigid external ballistic model, this paper establishes an external ballistic calculation model for deflectable nose projectile and further establishes the solving programs accordingly. Different angle of attack, velocity, coefficients of lift, resistance, and moment under the deflection can be obtained in this paper based on the previous experiments and emulation researches. In the end, the author pointed out the laws on the impaction of external ballistic trajectory by the deflection of nose of the missile.

  17. Proposed Design Procedure of a Helical Coil Heat Exchanger for an Orc Energy Recovery System for Vehicular Application

    Directory of Open Access Journals (Sweden)

    Giacomo Bonafoni

    2015-05-01

    Full Text Available There are several systems that produce energy from low grade heat sources such as Stirling engines, thermoelectric generators, and ORC (Organic Rankine Cycle systems. This paper shows the heat recovery from exhaust gases of a 1400 cc Diesel engine, to vaporize the working fluid of a small (<10 kW ORC system. The main objective is to have a system as compact as possible, to make it suitable for transport applications such as cars, ships, trains, etc. Three fluids were studied for this application: water and two refrigerant fluids: R134a and R245fa, which were found to be more appropriate than water at certain pressure and temperature values. Afterwards, a design procedure was proposed, then the heat exchanger was modeled and finally a steady-state thermal and structural analysis were carried out using a commercial software to find the temperature and the effects of the thermal stress on the material of the helical coiled tube.

  18. Generalized helicity and its time derivative

    International Nuclear Information System (INIS)

    Jarboe, T.R.; Marklin, G.J.

    1985-01-01

    Spheromaks can be sustained against resistive decay by helicity injection because they tend to obey the minimum energy principle. This principle states that a plasma-laden magnetic configuration will relax to a state of minimum energy subject to the constraint that the magnetic helicity is conserved. Use of helicity as a constraint on the minimization of energy was first proposed by Woltjer in connection with astrophysical phenomena. Helicity does decay on the resistive diffusion time. However, if helicity is created and made to flow continuoiusly into a confinement geometry, these additional linked fluxes can relax and sustain the configuration indefinitely against the resistive decay. In this paper we will present an extension of the definition of helicity to include systems where B vector can penetrate the boundary and the penetration can be varying in time. We then discuss the sustainment of RFPs and spheromaks in terms of helicity injection

  19. Measurement of vertical track deflection from a moving rail car.

    Science.gov (United States)

    2013-02-01

    The University of Nebraska has been conducting research sponsored by the Federal Railroad Administrations Office of Research and Development to develop a system that measures vertical track deflection/modulus from a moving rail car. Previous work ...

  20. Superconducting multi-cell trapped mode deflecting cavity

    Science.gov (United States)

    Lunin, Andrei; Khabiboulline, Timergali; Gonin, Ivan; Yakovlev, Vyacheslav; Zholents, Alexander

    2017-10-10

    A method and system for beam deflection. The method and system for beam deflection comprises a compact superconducting RF cavity further comprising a waveguide comprising an open ended resonator volume configured to operate as a trapped dipole mode; a plurality of cells configured to provide a high operating gradient; at least two pairs of protrusions configured for lowering surface electric and magnetic fields; and a main power coupler positioned to optimize necessary coupling for an operating mode and damping lower dipole modes simultaneously.

  1. Experimental studies on heat transfer and thermal performance characteristics of thermosyphon solar water heating system with helical and Left-Right twisted tapes

    International Nuclear Information System (INIS)

    Jaisankar, S.; Radhakrishnan, T.K.; Sheeba, K.N.

    2011-01-01

    Research highlights: → Conventional solar heaters are inefficient due to poor convective heat transfer. → Twisted tapes improve the heat transfer rate in solar water heater system. → Increase in outlet water temperature by 15 o C through the use of twisted tapes. →Thermal performance of twisted tape collector is 19% more than plain tube system. → Reduces collector area (0.6 m 2 ) whereas area for conventional collector is 1 m 2 . -- Abstract: Experimental investigation of heat transfer, friction factor and thermal performance of thermosyphon solar water heater system fitted with helical and Left-Right twist of twist ratio 3 has been performed and presented. The helical twisted tape induces swirl flow inside the riser tubes unidirectional over the length. But, in Left-Right system the swirl flow is bidirectional which increases the heat transfer and pressure drop when compared to the helical system. The experimental heat transfer and friction factors characteristics are validated with theoretical equations and the deviation falls with in the acceptable limits. The results show that heat transfer enhancement in twisted tape collector is higher than the plain tube collector. Compared to helical and Left-Right twisted tape system of same twist ratio 3, maximum thermal performance is obtained for Left-Right twisted tape collector with increase in solar intensity.

  2. New pellet production and acceleration technologies for high speed pellet injection system 'HIPEL' in large helical device

    International Nuclear Information System (INIS)

    Viniar, I.; Sudo, S.

    1994-12-01

    New technologies of pellet production and acceleration for fueling and diagnostics purposes in large thermonuclear reactors are proposed. The technologies are intended to apply to the multiple-pellet injection system 'HIPEL' for Large Helical Device of NIFS in Japan. The pellet production technology has already been tested in a pipe-gun type pellet injector. It will realize the repeating pellet injection by means of decreasing of the pellet formation time into the pipe-gun barrel. The acceleration technology is based upon a new pump tube operation in two-stage gas gun and also upon a new conception of the allowable pressure acting on a pellet into a barrel. Some preliminary estimations have been made, and principles of a pump tube construction providing for a reliable long term operation in the repeating mode without any troubles from a piston are proposed. (author)

  3. HIFLUX: OBLATE FRCS, DOUBLE HELICES,SPHEROMAKS AND RFPS IN ONE SYSTEM

    International Nuclear Information System (INIS)

    SCHAFFER, M.J.; BOEDO, J.A.

    2003-01-01

    OAK-B135 High magnetic flux is required for thermonuclear FRC reactors and, more immediately, to advance the FRC experimental program in general. Oblate FRCs are of special interest because they are predicted to have certain improved MHD stability over elongated FRCs, and oblate FRCs may yield the most compact, magnetically confined fusion reactors. Neither oblate nor high-flux FRCs have been investigated experimentally to date. Our presently proposed technique is to make two high-flux, oppositely-handed plasmas by a pair of large, external, reversed-field pinch (RFP) sources. The plasmas would propagate as two Taylor-relaxed double-helix plasmas, to an oblate main plasma chamber, where they would relax further to a counter-helicity pair of spheromaks, which would finally merge into a single high-flux FRC. A concept for a new experimental facility, HIFLUX, to make and study high-magnetic-flux oblate Field-Reversed Configuration (FRC) plasmas, is described. Similar principles might also enable high flux non-inductive startup of other plasma devices

  4. Optimized enhancement in helical CT: Experiences with a real-time bolus tracking system in 628 patients

    International Nuclear Information System (INIS)

    Kirchner, J.; Kickuth, R.; Laufer, U.; Noack, M.; Liermann, D.

    2000-01-01

    AIMS: Ultrafast detector technology enables bolus-triggered application of contrast media. In a prospective study we investigated the benefit of this new method with the intention of optimizing enhancement during examination of the chest and abdomen. MATERIALS AND METHODS: In total, we examined 548 patients under standardized conditions. All examinations were performed on a Somatom Plus 4 Power CT system (Siemens Corp., Forchheim, Germany) using the CARE-Bolus software. This produces repetitive low-dose test images (e.g. for the lung: 140 kV, 43 mA, TI 0.5 s) and measures the Hounsfield attenuation in a pre-selected region of interest. After exceeding a defined threshold, a diagnostic spiral CT examination was begun automatically. The data obtained from 321 abdominal CT and 179 lung CT examinations were correlated with different parameters such as age, weight and height of the patients and parameters of vascular access. In a group of 80 patients, the injection of contrast medium was stopped after reaching a pre-defined threshold of an increase of 100 HU over the baseline. Then, we assessed the maximal enhancement of liver, pulmonal artery trunk and aortic arch. RESULTS: There was no correlation between bolus geometry and age, body surface or weight. In helical CT of the abdomen the threshold was reached after a mean trigger time of 27 s (range 13-67 s) and only 65 ml (range 41-105 ml) of contrast medium were administered. In helical CT of the lung the threshold was reached after 21 s (range 12-48 s) and the mean amount of administered contrast medium was 48 ml (range 38-71 ml). CONCLUSION: Bolus triggering allows optimized enhancement of the organs and reduces the dose of contrast material required compared with standard administration. Kirchner, J. (2000). Clinical Radiology 55, 368-373

  5. Optimized enhancement in helical CT: experiences with a real-time bolus tracking system in 628 patients.

    Science.gov (United States)

    Kirchner, J; Kickuth, R; Laufer, U; Noack, M; Liermann, D

    2000-05-01

    Ultrafast detector technology enables bolus-triggered application of contrast media. In a prospective study we investigated the benefit of this new method with the intention of optimizing enhancement during examination of the chest and abdomen. In total, we examined 548 patients under standardized conditions. All examinations were performed on a Somatom Plus 4 Power CT system (Siemens Corp., Forchheim, Germany) using the CARE-Bolus software. This produces repetitive low-dose test images (e.g. for the lung: 140 kV, 43 mA, TI 0.5 s) and measures the Hounsfield attenuation in a pre-selected region of interest. After exceeding a defined threshold, a diagnostic spiral CT examination was begun automatically. The data obtained from 321 abdominal CT and 179 lung CT examinations were correlated with different parameters such as age, weight and height of the patients and parameters of vascular access. In a group of 80 patients, the injection of contrast medium was stopped after reaching a pre-defined threshold of an increase of 100 HU over the baseline. Then, we assessed the maximal enhancement of liver, pulmonal artery trunk and aortic arch. There was no correlation between bolus geometry and age, body surface or weight. In helical CT of the abdomen the threshold was reached after a mean trigger time of 27 s (range 13-67 s) and only 65 ml (range 41-105 ml) of contrast medium were administered. In helical CT of the lung the threshold was reached after 21 s (range 12-48 s) and the mean amount of administered contrast medium was 48 ml (range 38-71 ml). Bolus triggering allows optimized enhancement of the organs and reduces the dose of contrast material required compared with standard administration. Copyright 2000 The Royal College of Radiologists.

  6. Study on pipe deflection by using numerical method

    Science.gov (United States)

    Husaini; Zaki Mubarak, Amir; Agustiar, Rizki

    2018-05-01

    Piping systems are widely used in a refinery or oil and gas industry. The piping system must be properly designed to avoid failure or leakage. Pipe stress analysis is conducted to analyze the loads and critical stress occurred, so that the failure of the pipe can be avoided. In this research, it is analyzed the deflection of a pipe by using Finite Element Method. The pipe is made of A358 / 304SS SCH10S Stainless Steel. It is 16 inches in size with the distance between supports is 10 meters. The fluid flown is Liquid Natural Gas (LNG) with the range of temperature of -120 ° C to -170 ° C, and a density of 461.1 kg / m 3. The flow of LNG causes deflection of the pipe. The pipe deflection must be within the permissible tolerable range. The objective is to analyze the deflection occurred in the piping system. Based on the calculation and simulation, the deflection is 4.4983 mm, which is below the maximum limit of deflection allowed, which is 20.3 mm.

  7. Helicity content and tokamak applications of helicity

    International Nuclear Information System (INIS)

    Boozer, A.H.

    1986-05-01

    Magnetic helicity is approximately conserved by the turbulence associated with resistive instabilities of plasmas. To generalize the application of the concept of helicity, the helicity content of an arbitrary bounded region of space will be defined. The definition has the virtues that both the helicity content and its time derivative have simple expressions in terms of the poloidal and toroidal magnetic fluxes, the average toroidal loop voltage and the electric potential on the bounding surface, and the volume integral of E-B. The application of the helicity concept to tokamak plasmas is illustrated by a discussion of so-called MHD current drive, an example of a stable tokamak q profile with q less than one in the center, and a discussion of the possibility of a natural steady-state tokamak due to the bootstrap current coupling to tearing instabilities

  8. Comparison of the effectiveness of different immobilization systems in different body regions using daily megavoltage CT in helical tomotherapy

    Science.gov (United States)

    Cheng, K-F

    2014-01-01

    Objective: Effective immobilization is crucial for the accurate delivery of radiotherapy. This study aimed to compare the effectiveness of the commonly used immobilization systems for different body regions using megavoltage CT (MVCT). Methods: Daily treatment set-up data from 212 patients treated by helical tomotherapy (Accuray, Sunnyvale, CA) in 6 body regions (52 head and neck, 41 chest, 38 abdomen, 36 pelvis, 18 breast and 27 cranium) were obtained. Based on a verification tool using the pre-treatment MVCT, set-up corrections for each patient were recorded. Mean systematic and random errors of lateral, longitudinal, vertical and roll directions and three-dimensional vectors were compared between immobilization systems of each region. Results: Smaller set-up deviations were observed in the Orfit system (Orfit Industries NV, Wijnegem, Belgium) of the head and neck region, while the performance of immobilization systems for the chest, abdomen and pelvis regions was similar. Larger differences were noted in the breast group, where the prone BodyFIX® system (Medical Intelligence, Medizintechnik GmbH, Schwabmünchen, Germany) was less stable than the supine VacLok® system (CIVCO Medical Solutions, Orange City, IA). Conclusion: Differences were found between the immobilization systems in the head and neck region, in which the Orfit system was relatively more effective, whereas the VacLok and BodyFIX systems performed similarly in the chest, abdomen and pelvis regions. For the breast case, the supine position with VacLok was much more stable than the prone breast technique. The results provided references for the estimation of clinical target volume–planning target volume margins. Advances in knowledge: This is the first article on comprehensive comparisons performed in immobilization systems for main body regions that provides some practical recommendations. PMID:24398111

  9. AIDA: Asteroid Impact & Deflection Assessment

    Science.gov (United States)

    Cheng, A. F.; Galvez, A.; Carnelli, I.; Michel, P.; Rivkin, A.; Reed, C.

    2012-12-01

    To protect the Earth from a hazardous asteroid impact, various mitigation methods have been proposed, including deflection of the asteroid by a spacecraft impact. AIDA, consisting of two mission elements, the Double Asteroid Redirection Test (DART) and the Asteroid Impact Monitoring (AIM) mission, is a demonstration of asteroid deflection. To date, there has been no such demonstration, and there is major uncertainty in the result of a spacecraft impact onto an asteroid, that is, the amount of deflection produced by a given momentum input from the impact. This uncertainty is in part due to unknown physical properties of the asteroid surface, such as porosity and strength, and in part due to poorly understood impact physics such that the momentum carried off by ejecta is highly uncertain. A first mission to demonstrate asteroid deflection would not only be a major step towards gaining the capability to mitigate an asteroid hazard, but in addition it would return unique information on an asteroid's strength, other surface properties, and internal structure. This information return would be highly relevant to future human exploration of asteroids. We report initial results of the AIDA joint mission concept study undertaken by the Johns Hopkins Applied Physics Laboratory and ESA with support from NASA centers including Goddard, Johnson and Jet Propulsion Laboratory. For AIDA, the DART spacecraft impactor study is coordinated with an ESA study of the AIM mission, which would rendezvous with the same asteroid to measure effects of the impact. Unlike the previous Don Quijote mission study performed by ESA in 2005-2007, DART envisions an impactor spacecraft to intercept the secondary member of a binary near-Earth asteroid. DART includes ground-based observations to measure the deflection independently of the rendezvous spacecraft observations from AIM, which also measures deflection and provides detailed characterization of the target asteroid. The joint mission AIDA

  10. Helical Tomotherapy Quality Assurance

    International Nuclear Information System (INIS)

    Balog, John; Soisson, Emilie

    2008-01-01

    Helical tomotherapy uses a dynamic delivery in which the gantry, treatment couch, and multileaf collimator leaves are all in motion during treatment. This results in highly conformal radiotherapy, but the complexity of the delivery is partially hidden from the end-user because of the extensive integration and automation of the tomotherapy control systems. This presents a challenge to the medical physicist who is expected to be both a system user and an expert, capable of verifying relevant aspects of treatment delivery. A related issue is that a clinical tomotherapy planning system arrives at a customer's site already commissioned by the manufacturer, not by the clinical physicist. The clinical physicist and the manufacturer's representative verify the commissioning at the customer site before acceptance. Theoretically, treatment could begin immediately after acceptance. However, the clinical physicist is responsible for the safe and proper use of the machine. In addition, the therapists and radiation oncologists need to understand the important machine characteristics before treatment can proceed. Typically, treatment begins about 2 weeks after acceptance. This report presents an overview of the tomotherapy system. Helical tomotherapy has unique dosimetry characteristics, and some of those features are emphasized. The integrated treatment planning, delivery, and patient-plan quality assurance process is described. A quality assurance protocol is proposed, with an emphasis on what a clinical medical physicist could and should check. Additionally, aspects of a tomotherapy quality assurance program that could be checked automatically and remotely because of its inherent imaging system and integrated database are discussed

  11. Microbunch preserving bending system for a helical radiator at the European X-ray Free Electron Laser

    Directory of Open Access Journals (Sweden)

    Y. Li

    2010-08-01

    Full Text Available At the European X-ray Free Electron Laser there is a planar undulator system under construction called SASE3, which produces intense linearly polarized light in the wavelength range from 0.4–1.6 nm. Nevertheless there is a strong demand for circularly polarized radiation in this wavelength range. An important part of a potential solution is described in this paper. After the planar undulator the electron beam, which is completely bunched, is sent through a suitable radiator. This can be an economically and technically convenient method to generate radiation with polarization properties, which are determined only by the radiator. If in addition a bend is used to separate the light created by the linear SASE3 from that of the radiator, two beam lines may be served, one with planar and one with circular radiation. In this case the light of the helical radiator is not contaminated by the light generated by the planar system. In order to obtain coherent radiation in the radiator, the microbunching of the planar undulator must be preserved throughout the bend. This is the basic problem. In this paper a fundamental, basic study is made. Several solutions for bending systems are presented, whose complexities, wavelength ranges, and debunching effects are different. The expected circular polarization and radiation power by such a bend are simulated for a model radiator.

  12. Elevator deflections on the icing process

    Science.gov (United States)

    Britton, Randall K.

    1990-01-01

    The effect of elevator deflection of the horizontal stabilizer for certain icing parameters is investigated. Elevator deflection can severely change the lower and upper leading-edge impingement limits, and ice can accrete on the elevator itself. Also, elevator deflection had practically no effect on the maximum local collection efficiency. It is shown that for severe icing conditions (large water droplets), elevator deflections that increase the projected height of the airfoil can significantly increase the total collection efficiency of the airfoil.

  13. Care-bolus tracking systems in multislice-helical computed tomography - a new method in the screening of cardiovascular failure?

    International Nuclear Information System (INIS)

    Stueckle, C.A.; Kickuth, R.; Kirchner, E.M.; Liermann, D.; Kirchner, J.

    2002-01-01

    Purpose. Recently bolus tracking systems were developed to improve the timing of intravenous contrast media application in helical computed tomography. We investigated the benefit of this new method as a parameter of the cardiac function.Material and methods. Retrospective analysis of 64 patients which incidentally underwent bolus triggered contrast enhanced helical CT and invasive investigation of the heart within one week. All examinations were performed on the CT scanner Somatom Plus 4 Volume Zoom (Siemens Corp., Forchheim, Germany) using the C.A.R.E. trademark Bolus software. This performs repetitive low- dose test scans (e.g. for the abdomen: 140 kV, 20 mA, TI 0,5 s) and measures the Hounsfield attenuation (increase over the baseline) in a preselected region of interest. The displayed increase of vascular density over the time after peripheral contrast media injection (75 ml Iopromid (300 mg/ml), 2 ml/s) was categorised to three types: (a) rapid increase, (b) deceleration before a 100 HE threshold was reached and (c) one or more peaks. The findings of the invasive investigation of the heart were correlated to the findings of the bolus-tracking measurements.Results. The examinations were categorized as follows: 19 type A, 34 type B, 11 type C. We found a high significant correlation between the type of the Hounsfield attenuation and systolic pressure in the left ventricle. There was no correlation between the type of the Hounsfield attenuation and the diastolic pressure in the left ventricle, the pressures related to the right ventricle or the ejection fraction. The bolus- tacking system showed a sensitivity of 53, a specificity of 82, an accuracy of 70%, a positive predictive value of 70% and a negative predictive value of 70% in detection of left heart failure.Conclusion. The bolus tracking system C.A.R.E.-bolus copyright often shows atypical Hounsfield attenuation in cases of cardiac failure but is not suitable as a screening method of the cardiopulmonary

  14. Helical axis stellarator equilibrium model

    International Nuclear Information System (INIS)

    Koniges, A.E.; Johnson, J.L.

    1985-02-01

    An asymptotic model is developed to study MHD equilibria in toroidal systems with a helical magnetic axis. Using a characteristic coordinate system based on the vacuum field lines, the equilibrium problem is reduced to a two-dimensional generalized partial differential equation of the Grad-Shafranov type. A stellarator-expansion free-boundary equilibrium code is modified to solve the helical-axis equations. The expansion model is used to predict the equilibrium properties of Asperators NP-3 and NP-4. Numerically determined flux surfaces, magnetic well, transform, and shear are presented. The equilibria show a toroidal Shafranov shift

  15. Incorporation of a Helical Tube Heat Transfer Model in the MARS Thermal Hydraulic Systems Analysis Code for the T/H Analyses of the SMART Reactor

    International Nuclear Information System (INIS)

    Young Jin Lee; Bub Dong Chung; Jong Chull Jo; Hho Jung Kim; Un Chul Lee

    2004-01-01

    SMART is a medium sized integral type advanced pressurized water reactor currently under development at KAERI. The steam generators of SMART are designed with helically coiled tubes and these are designed to produce superheated steam. The helical shape of the tubes can induce strong centrifugal effect on the secondary coolant as it flows inside the tubes. The presence of centrifugal effect is expected to enhance the formation of cross-sectional circulation flows within the tubes that will increase the overall heat transfer. Furthermore, the centrifugal effect is expected to enhance the moisture separation and thus make it easier to produce superheated steam. MARS is a best-estimate thermal-hydraulic systems analysis code with multi-phase, multi-dimensional analysis capability. The MARS code was produced by restructuring and merging the RELAP5 and the COBRA-TF codes. However, MARS as well as most other best-estimate systems analysis codes in current use lack the detailed models needed to describe the thermal hydraulics of helically coiled tubes. In this study, the heat transfer characteristics and relevant correlations for both the tube and shell sides of helical tubes have been investigated, and the appropriate models have been incorporated into the MARS code. The newly incorporated helical tube heat transfer package is available to the MARS users via selection of the appropriate option in the input. A performance analysis on the steam generator of SMART under full power operation was carried out using the modified MARS code. The results of the analysis indicate that there is a significant improvement in the code predictability. (authors)

  16. Design study of a normal conducting helical snake for AGS

    CERN Document Server

    Takano, Junpei; Okamura, Masahiro; Roser, Thomas; MacKay, William W; Luccio, Alfredo U; Takano, Koji

    2004-01-01

    A new normal conducting snake magnet is being fabricated for the Alternate Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL). In the Relativistic Heavy Ion Collider (RHIC) project, a superconducting type helical dipole magnets had been developed and it performed successfully in high-energy polarized proton acceleration. The new AGS helical snake has the same basic magnetic structure but is more complicated. To achieve no beam shift and no beam deflection in one magnetic device, helical pitches and rotating angles were carefully calculated. Compared to a superconducting magnet, a normal warm magnet must have a large cross- sectional area of conductors which make it difficult to design a magnet with large helical pitch. We developed a modified window frame structure to accommodate the large number of conductors. Its three dimensional magnetic field was simulated by using OPERA3D/TOSCA. 3 Refs.

  17. Helical type vacuum container

    International Nuclear Information System (INIS)

    Owada, Kimio.

    1989-01-01

    Helical type vacuum containers in the prior art lack in considerations for thermal expansion stresses to helical coils, and there is a possibility of coil ruptures. The object of the present invention is to avoid the rupture of helical coils wound around the outer surface of a vacuum container against heat expansion if any. That is, bellows or heat expansion absorbing means are disposed to a cross section of a helical type vacuum container. With such a constitution, thermal expansion of helical coils per se due to temperature elevation of the coils during electric supply can be absorbed by expansion of the bellows or absorption of the heat expansion absorbing means. Further, this can be attained by arranging shear pins in the direction perpendicular to the bellows axis so that the bellows are not distorted when the helical coils are wound around the helical type vacuum container. (I.S.)

  18. Stiffness versus architecture of single helical polyisocyanopeptides

    NARCIS (Netherlands)

    Buul, van A.M.; Schwartz, E.; Brocorens, P.; Koepf, M.; Beljonne, D.; Maan, J.C.; Christianen, P.C.M.; Kouwer, P.H.J.; Nolte, R.J.M.; Engelkamp, H.; Blank, K.; Rowan, A.E.

    2013-01-01

    Helical structures play a vital role in nature, offering mechanical rigidity, chirality and structural definition to biological systems. Little is known about the influence of the helical architecture on the intrinsic properties of polymers. Here, we offer an insight into the nano architecture of

  19. Extension of high T{sub e} regime with upgraded electron cyclotron resonance heating system in the Large Helical Device

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, H., E-mail: takahashi.hiromi@LHD.nifs.ac.jp; Shimozuma, T.; Kubo, S.; Yoshimura, Y.; Igami, H.; Ito, S.; Kobayashi, S.; Mizuno, Y.; Okada, K.; Mutoh, T.; Nagaoka, K.; Osakabe, M.; Yamada, I.; Nakano, H.; Yokoyama, M.; Ido, T.; Shimizu, A.; Seki, R.; Ida, K.; Yoshinuma, M. [National Institute for Fusion Science, Toki 509-5292 (Japan); and others

    2014-06-15

    Enhancement of the output power per gyrotron has been planned in the Large Helical Device (LHD). Three 77-GHz gyrotrons with an output power of more than 1 MW have been operated. In addition, a high power gyrotron with the frequency of 154 GHz (1 MW/5 s, 0.5 MW/CW) was newly installed in 2012, and the total injection power of Electron cyclotron resonance heating (ECRH) reached 4.6 MW. The operational regime of ECRH plasma on the LHD has been extended due to the upgraded ECRH system such as the central electron temperature of 13.5 keV with the line-averaged electron density n{sub e-fir} = 1 × 10{sup 19} m{sup −3}. The electron thermal confinement clearly improved inside the electron internal transport barrier, and the electron thermal diffusivity reached neoclassical level. The global energy confinement time increased with increase of n{sub e-fir}. The plasma stored energy of 530 kJ with n{sub e-fir} = 3.2 × 10{sup 19} m{sup −3}, which is 1.7 times larger than the previous record in the ECRH plasma in the LHD, has been successfully achieved.

  20. Cavity resonance absorption in ultra-high bandwidth CRT deflection structure by a resistive load

    Science.gov (United States)

    Dunham, M.E.; Hudson, C.L.

    1993-05-11

    An improved ultra-high bandwidth helical coil deflection structure for a cathode ray tube is described comprising a first metal member having a bore therein, the metal walls of which form a first ground plane; a second metal member coaxially mounted in the bore of the first metal member and forming a second ground plane; a helical deflection coil coaxially mounted within the bore between the two ground planes; and a resistive load disposed in one end of the bore and electrically connected to the first and second ground planes, the resistive load having an impedance substantially equal to the characteristic impedance of the coaxial line formed by the two coaxial ground planes to inhibit cavity resonance in the structure within the ultra-high bandwidth of operation. Preferably, the resistive load comprises a carbon film on a surface of an end plug in one end of the bore.

  1. Resonant helical fields in tokamaks

    International Nuclear Information System (INIS)

    Okano, V.

    1990-01-01

    Poincare maps of magnetic field lines of a toroidal helical system were made. The magnetic field is a linear superposition of the magnetic fields produced by a toroidal plasma in equilibrium and by external helical currents. Analytical expression for the Poincare maps was no obtained since the magnetic field do not have symmetry. In order to obtain the maps, the equation minus derivative of l vector times B vector = 0 was numerically integrated. In the Poincare maps, the principal and the secondary magnetic island were observed. (author)

  2. An automatic dose verification system for adaptive radiotherapy for helical tomotherapy

    International Nuclear Information System (INIS)

    Mo, Xiaohu; Chen, Mingli; Parnell, Donald; Olivera, Gustavo; Galmarini, Daniel; Lu, Weiguo

    2014-01-01

    Purpose: During a typical 5-7 week treatment of external beam radiotherapy, there are potential differences between planned patient's anatomy and positioning, such as patient weight loss, or treatment setup. The discrepancies between planned and delivered doses resulting from these differences could be significant, especially in IMRT where dose distributions tightly conforms to target volumes while avoiding organs-at-risk. We developed an automatic system to monitor delivered dose using daily imaging. Methods: For each treatment, a merged image is generated by registering the daily pre-treatment setup image and planning CT using treatment position information extracted from the Tomotherapy archive. The treatment dose is then computed on this merged image using our in-house convolution-superposition based dose calculator implemented on GPU. The deformation field between merged and planning CT is computed using the Morphon algorithm. The planning structures and treatment doses are subsequently warped for analysis and dose accumulation. All results are saved in DICOM format with private tags and organized in a database. Due to the overwhelming amount of information generated, a customizable tolerance system is used to flag potential treatment errors or significant anatomical changes. A web-based system and a DICOM-RT viewer were developed for reporting and reviewing the results. Results: More than 30 patients were analysed retrospectively. Our in-house dose calculator passed 97% gamma test evaluated with 2% dose difference and 2mm distance-to-agreement compared with Tomotherapy calculated dose, which is considered sufficient for adaptive radiotherapy purposes. Evaluation of the deformable registration through visual inspection showed acceptable and consistent results, except for cases with large or unrealistic deformation. Our automatic flagging system was able to catch significant patient setup errors or anatomical changes. Conclusions: We developed an automatic

  3. Study on reinforced concrete beams with helical transverse reinforcement

    Science.gov (United States)

    Kaarthik Krishna, N.; Sandeep, S.; Mini, K. M.

    2018-02-01

    In a Reinforced Concrete (R.C) structure, major reinforcement is used for taking up tensile stresses acting on the structure due to applied loading. The present paper reports the behavior of reinforced concrete beams with helical reinforcement (transverse reinforcement) subjected to monotonous loading by 3-point flexure test. The results were compared with identically similar reinforced concrete beams with rectangular stirrups. During the test crack evolution, load carrying capacity and deflection of the beams were monitored, analyzed and compared. Test results indicate that the use of helical reinforcement provides enhanced load carrying capacity and a lower deflection proving to be more ductile, clearly indicating the advantage in carrying horizontal loads. An analysis was also carried out using ANSYS software in order to compare the test results of both the beams.

  4. Research and development of the system for group examination of lung cancer by helical CT

    International Nuclear Information System (INIS)

    2003-03-01

    For the ultimate purpose of heavy particle therapy of lung cancer at an early stage, the system in the title with low dose radiation has been investigated by cooperation of NIRS (as a leading part) and medical/industrial facilities all over the country. The project started essentially in 1984 and has been continuing at 2003. This book described Results hitherto and Materials for application to medical care at disaster (Hanshin-Awaji Earthquake Disaster in 1995) together with reference materials. Results contain all fields of nuclear medicine and of imaging involved in examination/diagnosis of lung cancer, achieved by NIRS, by Health management center and Faculty of Medicine, Chiba University and Japan Anti-Tuberculosis Association in Chiba, by the 3rd Department of Internal Medicine, Fac. Med., Chiba Univ., by Osaka Medical Center for Cancer and Cardiovascular Diseases, by Nippon Med. School, Arakawa-ku cancer protection center and Tokyo Metropolitan Univ. of Health Sciences, by Hitachi health management center, by Fukui Med. College, by Hitachi Medical Corp., by NTT research laboratories, and by Toyohashi Univ. of Technology. The Materials involve Process and summary of conducting the medical care activities, Improvement of the examination automobile, Supplementary equipments and measures for legal problems, System for the medical care activities, Record of the examination automobile activities, Problems in future, and Completion of the medical activities. Reference materials are related with the Materials above. (N.I.)

  5. Field distribution analysis in deflecting structures

    Energy Technology Data Exchange (ETDEWEB)

    Paramonov, V.V. [Joint Inst. for Nuclear Research, Moscow (Russian Federation)

    2013-02-15

    Deflecting structures are used now manly for bunch rotation in emittance exchange concepts, bunch diagnostics and to increase the luminosity. The bunch rotation is a transformation of a particles distribution in the six dimensional phase space. Together with the expected transformations, deflecting structures introduce distortions due to particularities - aberrations - in the deflecting field distribution. The distributions of deflecting fields are considered with respect to non linear additions, which provide emittance deteriorations during a transformation. The deflecting field is treated as combination of hybrid waves HE{sub 1} and HM{sub 1}. The criteria for selection and formation of deflecting structures with minimized level of aberrations are formulated and applied to known structures. Results of the study are confirmed by comparison with results of numerical simulations.

  6. Field distribution analysis in deflecting structures

    International Nuclear Information System (INIS)

    Paramonov, V.V.

    2013-02-01

    Deflecting structures are used now manly for bunch rotation in emittance exchange concepts, bunch diagnostics and to increase the luminosity. The bunch rotation is a transformation of a particles distribution in the six dimensional phase space. Together with the expected transformations, deflecting structures introduce distortions due to particularities - aberrations - in the deflecting field distribution. The distributions of deflecting fields are considered with respect to non linear additions, which provide emittance deteriorations during a transformation. The deflecting field is treated as combination of hybrid waves HE 1 and HM 1 . The criteria for selection and formation of deflecting structures with minimized level of aberrations are formulated and applied to known structures. Results of the study are confirmed by comparison with results of numerical simulations.

  7. Modulus of Subgrade Reaction and Deflection

    Directory of Open Access Journals (Sweden)

    Austin Potts

    2009-01-01

    Full Text Available Differential equations govern the bending and deflection of roads under a concentrated load. Identifying critical parameters, such as the maximum deflection and maximum bending moments of a street supported by an elastic subgrade, is key to designing safe and reliable roadways. This project solves the underlying differential equation in pavement deflection and tests various parameters to highlight the importance in selecting proper foundation materials.

  8. LHD helical divertor

    International Nuclear Information System (INIS)

    Ohyabu, N.; Watanabe, T.; Ji Hantao

    1993-07-01

    The Large Helical Device (LHD) now under construction is a heliotron/torsatron device with a closed divertor system. The edge LHD magnetic structure has been studied in detail. A peculiar feature of the configuration is existence of edge surface layers, a complicated three dimensional magnetic structure which does not, however, seem to hamper the expected divertor functions. Two divertor operational modes are being considered for the LHD experiment, high density, cold radiative divertor operation as a safe heat removal scheme and high temperature divertor plasma operation. In the latter operation, a divertor plasma with temperature of a few kev, generated by efficient pumping, expects to lead to significant improvement in core plasma confinement. Conceptual designs of the LHD divertor components are under way. (author)

  9. UWB Wind Turbine Blade Deflection Sensing for Wind Energy Cost Reduction

    DEFF Research Database (Denmark)

    Zhang, Shuai; Jensen, Tobias Lindstrøm; Franek, Ondrej

    2015-01-01

    A new application of utilizing ultra-wideband (UWB) technology to sense wind turbine blade deflections is introduced in this paper for wind energy cost reduction. The lower UWB band of 3.1–5.3 GHz is applied. On each blade, there will be one UWB blade deflection sensing system, which consists...... is always of sufficient quality for accurate estimations under different deflections. The measured results reveal that the blade tip-root distance and blade deflection can be accurately estimated in the complicated and lossy wireless channels around a wind turbine blade. Some future research topics...

  10. Dual deflectable beam strip engine development.

    Science.gov (United States)

    Dulgeroff, C. R.; Zuccaro, D. E.; Kami, S.; Schnelker, D. E.; Ward, J. W.

    1972-01-01

    This paper describes a dual beam thruster that has been designed, constructed, and tested. The system is suitable for two-axes attitude control and is comprised of two orthogonal strips, each capable of producing 0.30 mlb thrust and beam deflections of more than plus or minus 20 deg. The nominal specific impulse for the thruster is 5000 sec, and the thrust level from each strip can be varied from 0 to 100%. Neutralizer filaments that were developed and life tested over 2000 hours producing more than 40 mA of electron emission per watt of input power are also discussed. The system power required for clean ionizers is approximately 200 W.

  11. Superconducting Helical Snake Magnet for the AGS

    CERN Document Server

    Willen, Erich; Escallier, John; Ganetis, George; Ghosh, Arup; Gupta, Ramesh C; Harrison, Michael; Jain, Animesh K; Luccio, Alfredo U; MacKay, William W; Marone, Andrew; Muratore, Joseph F; Okamura, Masahiro; Plate, Stephen R; Roser, Thomas; Tsoupas, Nicholaos; Wanderer, Peter

    2005-01-01

    A superconducting helical magnet has been built for polarized proton acceleration in the Brookhaven AGS. This "partial Snake" magnet will help to reduce the loss of polarization of the beam due to machine resonances. It is a 3 T magnet some 1940 mm in magnetic length in which the dipole field rotates with a pitch of 0.2053 degrees/mm for 1154 mm in the center and a pitch of 0.3920 degrees/mm for 393 mm in each end. The coil cross-section is made of two slotted cylinders containing superconductor. In order to minimize residual offsets and deflections of the beam on its orbit through the Snake, a careful balancing of the coil parameters was necessary. In addition to the main helical coils, a solenoid winding was built on the cold bore tube inside the main coils to compensate for the axial component of the field that is experienced by the beam when it is off-axis in this helical magnet. Also, two dipole corrector magnets were placed on the same tube with the solenoid. A low heat leak cryostat was built so that t...

  12. Force-deflection behavior of piezoelectric actuators

    Science.gov (United States)

    Singh, Ashok K.; Nagpal, Pawan

    2001-11-01

    In the present endeavour, force - deflection behavior of various piezoelectric actuator configurations has been analyzed for performance comparison. The response of stack actuator has been simulated using MATLAB Simulink, in a stack actuator-pendulum configuration. During simulation, stack actuator has been used in charge control feedback mode, because of the advantage of low hysteresis, and high linearity. The model incorporates three compensation blocks, viz 1) a PID position controller, 2) a PI piezoelectric current controller, and 3) a dynamic force feedback. A typical stack actuator, having 130 layers, 1.20x10-4 m thickness, 3.46x10-5m2 cross sectional area, of PZT-5H type, has been utilized for simulation. The response of the system has been tested by applying a sinusoidal input of frequency 500 Hz, and waveform amplitude of 1x10-3V.

  13. Modelling simple helically delivered dose distributions

    International Nuclear Information System (INIS)

    Fenwick, John D; Tome, Wolfgang A; Kissick, Michael W; Mackie, T Rock

    2005-01-01

    In a previous paper, we described quality assurance procedures for Hi-Art helical tomotherapy machines. Here, we develop further some ideas discussed briefly in that paper. Simple helically generated dose distributions are modelled, and relationships between these dose distributions and underlying characteristics of Hi-Art treatment systems are elucidated. In particular, we describe the dependence of dose levels along the central axis of a cylinder aligned coaxially with a Hi-Art machine on fan beam width, couch velocity and helical delivery lengths. The impact on these dose levels of angular variations in gantry speed or output per linear accelerator pulse is also explored

  14. Evidence for Mixed Helicity in Erupting Filaments

    Science.gov (United States)

    Muglach, K.; Wang, Y.-M.; Kliem, B.

    2009-09-01

    Erupting filaments are sometimes observed to undergo a rotation about the vertical direction as they rise. This rotation of the filament axis is generally interpreted as a conversion of twist into writhe in a kink-unstable magnetic flux rope. Consistent with this interpretation, the rotation is usually found to be clockwise (as viewed from above) if the post-eruption arcade has right-handed helicity, but counterclockwise if it has left-handed helicity. Here, we describe two non-active-region filament events recorded with the Extreme-Ultraviolet Imaging Telescope on the Solar and Heliospheric Observatory in which the sense of rotation appears to be opposite to that expected from the helicity of the post-event arcade. Based on these observations, we suggest that the rotation of the filament axis is, in general, determined by the net helicity of the erupting system, and that the axially aligned core of the filament can have the opposite helicity sign to the surrounding field. In most cases, the surrounding field provides the main contribution to the net helicity. In the events reported here, however, the helicity associated with the filament "barbs" is opposite in sign to and dominates that of the overlying arcade.

  15. Radiation characteristics of helical tomotherapy

    International Nuclear Information System (INIS)

    Jeraj, Robert; Mackie, Thomas R.; Balog, John; Olivera, Gustavo; Pearson, Dave; Kapatoes, Jeff; Ruchala, Ken; Reckwerdt, Paul

    2004-01-01

    Helical tomotherapy is a dedicated intensity modulated radiation therapy (IMRT) system with on-board imaging capability (MVCT) and therefore differs from conventional treatment units. Different design goals resulted in some distinctive radiation field characteristics. The most significant differences in the design are the lack of flattening filter, increased shielding of the collimators, treatment and imaging operation modes and narrow fan beam delivery. Radiation characteristics of the helical tomotherapy system, sensitivity studies of various incident electron beam parameters and radiation safety analyses are presented here. It was determined that the photon beam energy spectrum of helical tomotherapy is similar to that of more conventional radiation treatment units. The two operational modes of the system result in different nominal energies of the incident electron beam with approximately 6 MeV and 3.5 MeV in the treatment and imaging modes, respectively. The off-axis mean energy dependence is much lower than in conventional radiotherapy units with less than 5% variation across the field, which is the consequence of the absent flattening filter. For the same reason the transverse profile exhibits the characteristic conical shape resulting in a 2-fold increase of the beam intensity in the center. The radiation leakage outside the field was found to be negligible at less than 0.05% because of the increased shielding of the collimators. At this level the in-field scattering is a dominant source of the radiation outside the field and thus a narrow field treatment does not result in the increased leakage. The sensitivity studies showed increased sensitivity on the incident electron position because of the narrow fan beam delivery and high sensitivity on the incident electron energy, as common to other treatment systems. All in all, it was determined that helical tomotherapy is a system with some unique radiation characteristics, which have been to a large extent

  16. Conceptual design of high resolution and reliable density measurement system on helical reactor FFHR-d1 and demonstration on LHD

    International Nuclear Information System (INIS)

    Akiyama, T.; Yasuhara, R.; Isobe, M.; Sakamoto, R.; Goto, T.; Kawahata, K.; Sagara, A.; Nakayama, K.; Okajima, S.

    2014-10-01

    This paper describes a conceptual design of the density measurement system on the helical reactor FFHR-d1 based on its quantitative operation scenario. The density measurement is required to meet the reactor design, and to have a high density resolution of the order of 10 17 m -3 with a time resolution of 10 ms and high reliability (no fringe jump). “A dispersion interferometer” is designed and a prototype is tested and installed on LHD, which can realize a demo relevant density plasma. The prototype demonstrates the feasibility on a demo reactor. (author)

  17. Dynamic Analysis of Helical Planetary Gear Sets under Combined Force and Moment Loading

    Directory of Open Access Journals (Sweden)

    Yanfang Liu

    2017-01-01

    Full Text Available The dynamic behavior of a single-stage planetary gear set with helical gears of multishaft automotive automatic transmissions has been studied, in which one component of the planetary gear set is imposed by additional external vertical and axial loading from countershaft gear pair in addition to the moment. Under these combined loading conditions, the contributions of the deflections of the ring gear and the carrier cannot be neglected. A three-dimensional nonlinear time-variant dynamic model considering not only the transverse, torsional, axial, and rotational motions of the gears but also the elasticity of the mounted shafts has been developed by combining the lumped parameter method with finite element method. The natural modes and the forced vibration responses due to static transmission errors have been obtained. The proposed dynamic model is employed to describe the effects of the combined external loading condition and positioning on the dynamic behavior of a four-planet system.

  18. Dynamics of helicity transport and Taylor relaxation

    International Nuclear Information System (INIS)

    Diamond, P.H.; Malkov, M.

    2003-01-01

    A simple model of the dynamics of Taylor relaxation is derived using symmetry principles alone. No statistical closure approximations are invoked or detailed plasma model properties assumed. Notably, the model predicts several classes of nondiffusive helicity transport phenomena, including traveling nonlinear waves and superdiffusive turbulent pulses. A universal expression for the scaling of the effective magnetic Reynolds number of a system undergoing Taylor relaxation is derived. Some basic properties of intermittency in helicity transport are examined

  19. A note on helicity

    International Nuclear Information System (INIS)

    Bialynicki-Birula, I.; Newmann, E.T.; Porter, J.; Winicour, J.; Lukacs, B.; Perjes, Z.; Sebestyen, A.

    1981-03-01

    The authors give a formal definition of the helicity operator for integral spin fields, which does not involve their momentum-space decomposition. The discussion is based upon a representation of the Pauli-Lubanski operator in terms of the action on tensor fields by the Killing vectors associated with the generators of the Poincare group. This leads to an identification of the helicity operator with the duality operator defined by the space-time alternating tensor. Helicity eigenstates then correspond to self-dual or anti-self-dual fields, in agreement with usage implicit in the literature. In addiition, the relationship between helicity eigenstates which are intrinsically non-classical, and states of right or left circular polarization in classical electrodynamics are discussed. (author)

  20. A small-gap electrostatic micro-actuator for large deflections

    Science.gov (United States)

    Conrad, Holger; Schenk, Harald; Kaiser, Bert; Langa, Sergiu; Gaudet, Matthieu; Schimmanz, Klaus; Stolz, Michael; Lenz, Miriam

    2015-01-01

    Common quasi-static electrostatic micro actuators have significant limitations in deflection due to electrode separation and unstable drive regions. State-of-the-art electrostatic actuators achieve maximum deflections of approximately one third of the electrode separation. Large electrode separation and high driving voltages are normally required to achieve large actuator movements. Here we report on an electrostatic actuator class, fabricated in a CMOS-compatible process, which allows high deflections with small electrode separation. The concept presented makes the huge electrostatic forces within nanometre small electrode separation accessible for large deflections. Electrostatic actuations that are larger than the electrode separation were measured. An analytical theory is compared with measurement and simulation results and enables closer understanding of these actuators. The scaling behaviour discussed indicates significant future improvement on actuator deflection. The presented driving concept enables the investigation and development of novel micro systems with a high potential for improved device and system performance. PMID:26655557

  1. Helical CT defecography

    International Nuclear Information System (INIS)

    Ferrando, R.; Fiorini, G.; Beghello, A.; Cicio, G.R.; Derchi, L.E.; Consigliere, M.; Resasco, M.; Tornago, S.

    1999-01-01

    The purpose of this work is to investigate the possible role of Helical CT defecography in pelvic floor disorders by comparing the results of the investigations with those of conventional defecography. The series analyzed consisted of 90 patients, namely 62 women and 28 men, ranging in age 24-82 years. They were all submitted to conventional defecography, and 18 questionable cases were also studied with Helical CT defecography. The conventional examination was performed during the 4 standard phases of resting, squeezing, Valsalva and straining; it is used a remote-control unit. The parameters for Helical CT defecography were: 5 mm beam collimation, pitch 2, 120 KV, 250 m As and 18-20 degrees gantry inclination to acquire coronal images of the pelvic floor. The rectal ampulla was distended with a bolus of 300 mL nonionic iodinated contrast agent (dilution: 3g/cc). The patient wore a napkin and was seated on the table, except for those who could not hold the position and were thus examined supine. Twenty-second helical scans were performed at rest and during evacuation; multiplanar reconstructions were obtained especially on the sagittal plane for comparison with conventional defecographic images. Coronal Helical CT defecography images permitted to map the perineal floor muscles, while sagittal reconstructions provided information on the ampulla and the levator ani. To conclude, Helical CT defecography performed well in study of pelvic floor disorders and can follow conventional defecography especially in questionable cases [it

  2. Synthesis of focusing-and-deflection columns

    International Nuclear Information System (INIS)

    Szilagyi, M.; Mui, P.H.

    1995-01-01

    Szilagyi and Szep have demonstrated that focusing lenses of high performances can be constructed from a column of circular plate electrodes. Later, Szilagyi modified that system to include dipole, quadrupole, and octupole components by partitioning each plate into eight equal sectors. It has already been shown that the additional quadrupole components can indeed bring about substantial improvements in the focusing of charged particle beams. In this article, that design procedure is expanded to construct columns capable of both focusing and deflecting particle beams by just introducing additional dipole components. In this new design, the geometry of the system remains unchanged. The only extra complication is the demand for more individual controls of the sector voltages. Two sample designs, one for negative ions and one for electrons, are presented showing that in both cases a ±2.3 mrad diverging beam can be focused down to a spot of less than 50 nm in radius over a scanning circular area of radius 0.25 mm. The details of the two systems are given in Sec. IV along with the source conditions. The performance of the negative ion system is found to be comparable to the published data. For the relativistic electron system, the interaction of individual components to reduce various aberrations is investigated. copyright 1995 American Vacuum Society

  3. A helical scintillating fiber hodoscope

    CERN Document Server

    Altmeier, M; Bisplinghoff, J; Bissel, T; Bollmann, R; Busch, M; Büsser, K; Colberg, T; Demiroers, L; Diehl, O; Dohrmann, F; Engelhardt, H P; Eversheim, P D; Felden, O; Gebel, R; Glende, M; Greiff, J; Gross, A; Gross-Hardt, R; Hinterberger, F; Jahn, R; Jeske, M; Jonas, E; Krause, H; Lahr, U; Langkau, R; Lindemann, T; Lindlein, J; Maier, R; Maschuw, R; Mayer-Kuckuck, T; Meinerzhagen, A; Naehle, O; Pfuff, M; Prasuhn, D; Rohdjess, H; Rosendaal, D; Von Rossen, P; Sanz, B; Schirm, N; Schulz-Rojahn, M; Schwarz, V; Scobel, W; Thomas, S; Trelle, H J; Weise, E; Wellinghausen, A; Wiedmann, W; Woller, K; Ziegler, R

    1999-01-01

    A novel scintillating fiber hodoscope in helically cylindric geometry has been developed for detection of low multiplicity events of fast protons and other light charged particles in the internal target experiment EDDA at the Cooler Synchrotron COSY. The hodoscope consists of 640 scintillating fibers (2.5 mm diameter), arranged in four layers surrounding the COSY beam pipe. The fibers are helically wound in opposing directions and read out individually using 16-channel photomultipliers connected to a modified commercial encoding system. The detector covers an angular range of 9 deg. <= THETA<=72 deg. and 0 deg. <=phi (cursive,open) Greek<=360 deg. in the lab frame. The detector length is 590 mm, the inner diameter 161 mm. Geometry and granularity of the hodoscope afford a position resolution of about 1.3 mm. The detector design took into consideration a maximum of reliability and a minimum of maintenance. An LED array may be used for monitoring purposes. (author)

  4. Helical CT of ureteral disease

    International Nuclear Information System (INIS)

    Cikman, Pablo; Bengio, Ruben; Bulacio, Javier; Zirulnik, Esteban; Garimaldi, Jorge

    2000-01-01

    Among the new applications of helical CT is the study of the ureteral pathology. The objective of this paper was to evaluate patients with suspected pathology of this organ and the repercussion in the therapeutic plans. We studied 23 patients with a helical CT protocol, without IV contrast injection and performed multiplanar reconstruction (MPR). We called this procedure Pielo CT. Thirteen ureteral stones were detected, 6 calculi, 2 urinary tract tumors, dilatation of the system in a patient with neo-bladder. In 2 patients, in whom ureteral pathology was ruled out, we found other alterations that explained the symptoms, (gallbladder stones, disk protrusion). The Pielo CT let decide a therapeutical approach in 20 or 21 patients with ureteral pathology. (author)

  5. Permanent deformation and deflection relationship from pavement condition assessment

    Directory of Open Access Journals (Sweden)

    Fabricio Leiva-Villacorta

    2017-07-01

    Full Text Available The development of permanent deformation in flexible pavements has been a research topic for several decades. Currently there are models included in the structural design of pavements that can predict this type of failure. However, the variables required for the prediction of this distress are complex or difficult to obtain in the field, making its application in pavement evaluation also difficult. Measurement of the deflection of pavement structures by means of non-destructive testing is a technique used to assess the condition of the pavement. This research study seeks to correlate data from deflections of the pavement surface with probable permanent deformation in time. In addition, prediction of the remaining life of the pavement structure using a specified criterion is also analyzed. In order to accomplish these objectives, data acquired from 4 different full scale accelerated pavement test tracks was used to develop a permanent deformation model as a function of deflection, load repetitions and pavement layer thickness. The developed model considered a time series model that incorporates an Auto-regressive parameter of order 1. The proposed model presents an advantage over currently available models because it reduces the required parameters to predict the permanent deformation and/or remaining life in the structure and because these variables can be easily found and updated in a pavement management system. Keywords: HVS, Permanent deformation, Deflections, APT, Time series, Instrumentation

  6. SLAC's Polarized Electron Source LaserSystem and Minimization of Helicity Correlations for the E-158 Parity Violation Experiment

    CERN Document Server

    Humensky, T

    2002-01-01

    SLAC E-158 is an experiment designed to make the first measurement of parity violation in Moeller scattering. E-158 will measure the right-left cross-section asymmetry, A sub L sub R sup M sup o sup e sup l sup l sup e sup r , in the elastic scattering of a 45-GeV polarized electron beam off unpolarized electrons in a liquid hydrogen target. E-158 plans to measure the expected Standard Model asymmetry of approx 10 sup - sup 7 to an accuracy of better than 10 sup - sup 8. To make this measurement, the polarized electron source requires for operation an intense circularly polarized laser beam and the ability to quickly switch between right- and left-helicity polarization states with minimal right-left helicity-correlated asymmetries in the resulting beam parameters (intensity, position, angle, spot size, and energy), sup b sup e sup a sup m A sub L sub R 's. This laser beam is produced by a unique SLAC-designed flashlamp-pumped Ti:Sapphire laser and is propagated through a carefully designed set of polarization...

  7. Mexico East-West Deflections (DMEX97)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' surface deflection of the vertical grid for Mexico, and North-Central is the DMEX97 model. The computation used about one million terrestrial and marine...

  8. Alaska North-South Deflections (DEFLEC96)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' x 4' surface deflection of the vertical grid for Alaska is the DEFLEC96 model. The computation used about 1.1 million terrestrial and marine gravity data...

  9. Mexico North-South Deflections (DMEX97)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' surface deflection of the vertical grid for Mexico, and North-Central is the DMEX97 model. The computation used about one million terrestrial and marine...

  10. Large membrane deflection via capillary force actuation

    Science.gov (United States)

    Barth, Christina A.; Hu, Xiaoyu; Mibus, Marcel A.; Reed, Michael L.; Knospe, Carl R.

    2018-06-01

    Experimental results from six prototype devices demonstrate that pressure changes induced in a liquid bridge via electrowetting can generate large deflections (20–75 µm) of an elastomeric membrane similar to those used in lab-on-a-chip microfluidic devices. In all cases deflections are obtained with a low voltage (20 V) and very small power consumption (<1 µW). The effects of variations in the bridge size and membrane dimensions on measured displacements are examined. Theoretical predictions are in good agreement with the measured displacements in those cases where the liquid contact angles could be measured within the devices during electrowetting. Contact angle hysteresis and charge injection into the dielectric layers limited the repeatability of deflection behavior during repeated cycling. Approaches for achieving greater deflections and improved repeatability are discussed.

  11. Alaska East-West Deflections (DEFLEC96)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' x 4' surface deflection of the vertical grid for Alaska is the DEFLEC96 model. The computation used about 1.1 millionterrestrial and marine gravity data held...

  12. Measurement methods of building structures deflections

    Directory of Open Access Journals (Sweden)

    Wróblewska Magdalena

    2018-01-01

    Full Text Available Underground mining exploitation is leading to the occurrence of deformations manifested by, in particular, sloping terrain. The structures situated on the deforming subsoil are subject to uneven subsidence which is leading in consequence to their deflection. Before a building rectification process takes place by, e.g. uneven raising, the structure's deflection direction and value is determined so that the structure is restored to its vertical position as a result of the undertaken remedial measures. Deflection can be determined by applying classical as well as modern measurement techniques. The article presents examples of measurement methods used considering the measured elements of building structures’ constructions and field measurements. Moreover, for a given example of a mining area, the existing deflections of buildings were compared with mining terrain sloping.

  13. Shielded serpentine traveling wave tube deflection structure

    Science.gov (United States)

    Hudson, C.L.; Spector, J.

    1994-12-27

    A shielded serpentine slow wave deflection structure is disclosed having a serpentine signal conductor within a channel groove. The channel groove is formed by a serpentine channel in a trough plate and a ground plane. The serpentine signal conductor is supported at its ends by coaxial feed through connectors. A beam interaction trough intersects the channel groove to form a plurality of beam interaction regions wherein an electron beam may be deflected relative to the serpentine signal conductor. 4 figures.

  14. Light deflection in gadolinium molybdate ferroelastic crystals

    International Nuclear Information System (INIS)

    Staniorowski, Piotr; Bornarel, Jean

    2000-01-01

    The deflection of a He-Ne light beam by polydomain gadolinium molybdate (GMO) crystals has been studied with respect to incidence angle α i on the sample at room temperature. The A and B deflected beams do not cross each other during the α i variation, in contrast to results and calculations previously published. The model using the Fresnel equation confirms this result. The model presented is more accurate for numerical calculation than that using the Huygens construction. (author)

  15. Helicity, Reconnection, and Dynamo Effects

    International Nuclear Information System (INIS)

    Ji, Hantao

    1998-01-01

    The inter-relationships between magnetic helicity, magnetic reconnection, and dynamo effects are discussed. In laboratory experiments, where two plasmas are driven to merge, the helicity content of each plasma strongly affects the reconnection rate, as well as the shape of the diffusion region. Conversely, magnetic reconnection events also strongly affect the global helicity, resulting in efficient helicity cancellation (but not dissipation) during counter-helicity reconnection and a finite helicity increase or decrease (but less efficiently than dissipation of magnetic energy) during co-helicity reconnection. Close relationships also exist between magnetic helicity and dynamo effects. The turbulent electromotive force along the mean magnetic field (alpha-effect), due to either electrostatic turbulence or the electron diamagnetic effect, transports mean-field helicity across space without dissipation. This has been supported by direct measurements of helicity flux in a laboratory plasma. When the dynamo effect is driven by electromagnetic turbulence, helicity in the turbulent field is converted to mean-field helicity. In all cases, however, dynamo processes conserve total helicity except for a small battery effect, consistent with the observation that the helicity is approximately conserved during magnetic relaxation

  16. Depicting mass flow rate of R134a /LPG refrigerant through straight and helical coiled adiabatic capillary tubes of vapor compression refrigeration system using artificial neural network approach

    Science.gov (United States)

    Gill, Jatinder; Singh, Jagdev

    2018-07-01

    In this work, an experimental investigation is carried out with R134a and LPG refrigerant mixture for depicting mass flow rate through straight and helical coil adiabatic capillary tubes in a vapor compression refrigeration system. Various experiments were conducted under steady-state conditions, by changing capillary tube length, inner diameter, coil diameter and degree of subcooling. The results showed that mass flow rate through helical coil capillary tube was found lower than straight capillary tube by about 5-16%. Dimensionless correlation and Artificial Neural Network (ANN) models were developed to predict mass flow rate. It was found that dimensionless correlation and ANN model predictions agreed well with experimental results and brought out an absolute fraction of variance of 0.961 and 0.988, root mean square error of 0.489 and 0.275 and mean absolute percentage error of 4.75% and 2.31% respectively. The results suggested that ANN model shows better statistical prediction than dimensionless correlation model.

  17. Helicity conservation under quantum reconnection of vortex rings.

    Science.gov (United States)

    Zuccher, Simone; Ricca, Renzo L

    2015-12-01

    Here we show that under quantum reconnection, simulated by using the three-dimensional Gross-Pitaevskii equation, self-helicity of a system of two interacting vortex rings remains conserved. By resolving the fine structure of the vortex cores, we demonstrate that the total length of the vortex system reaches a maximum at the reconnection time, while both writhe helicity and twist helicity remain separately unchanged throughout the process. Self-helicity is computed by two independent methods, and topological information is based on the extraction and analysis of geometric quantities such as writhe, total torsion, and intrinsic twist of the reconnecting vortex rings.

  18. Hydrodynamic studies of CNT nanofluids in helical coil heat exchanger

    Science.gov (United States)

    Babita; Sharma, S. K.; Mital Gupta, Shipra; Kumar, Arinjay

    2017-12-01

    Helical coils are extensively used in several industrial processes such as refrigeration systems, chemical reactors, recovery processes etc to accommodate a large heat transfer area within a smaller space. Nanofluids are getting great attention due to their enhanced heat transfer capability. In heat transfer equipments, pressure drop is one of the major factors of consideration for pumping power calculations. So, the present work is aimed to study hydrodynamics of CNT nanofluids in helical coils. In this study, pressure drop characteristics of CNT nanofluid flowing inside horizontal helical coils are investigated experimentally. The helical coil to tube diameter was varied from 11.71 to 27.34 keeping pitch of the helical coil constant. Double distilled water was used as basefluid. SDBS and GA surfactants were added to stablilize CNT nanofluids. The volumetric fraction of CNT nanofluid was varied from 0.003 vol% to 0.051 vol%. From the experimental data, it was analyzed that the friction factor in helical coils is greater than that of straight tubes. Concentration of CNT in nanofluids also has a significant influence on the pressure drop/friction factor of helical coils. At a constant concentration of CNT, decreasing helical coil to tube diameter from 27.24 to 11.71, fanning friction factor of helical coil; f c increases for a constant value of p/d t. This increase in the value of fanning friction factor can be attributed to the secondary flow of CNT nanofluid in helical coils.

  19. Helical-D pinch

    International Nuclear Information System (INIS)

    Schaffer, M.J.

    1997-08-01

    A stabilized pinch configuration is described, consisting of a D-shaped plasma cross section wrapped tightly around a guiding axis. The open-quotes helical-Dclose quotes geometry produces a very large axial (toroidal) transform of magnetic line direction that reverses the pitch of the magnetic lines without the need of azimuthal (poloidal) plasma current. Thus, there is no need of a open-quotes dynamoclose quotes process and its associated fluctuations. The resulting configuration has the high magnetic shear and pitch reversal of the reversed field pinch (RFP). (Pitch = P = qR, where R = major radius). A helical-D pinch might demonstrate good confinement at q << 1

  20. Experimental investigation of solar powered diaphragm and helical pumps

    Science.gov (United States)

    For several years, many types of solar powered water pumping systems were evaluated, and in this paper, diaphragm and helical solar photovoltaic (PV) powered water pumping systems are discussed. Data were collected on diaphragm and helical pumps which were powered by different solar PV arrays at mul...

  1. Compensation of aberrations of deflected electron probe by means of dynamical focusing with stigmator

    International Nuclear Information System (INIS)

    Baba, Norio; Ebe, Toyoe; Ikehata, Koichi; Ito, Yasuhiro; Terada, Hiroshi

    1979-01-01

    Electron beam passing through a deflecting field is in general, subjected to aberrations such as distortion, astigmatism and coma in accordance with the deflecting angle. Accordingly the aberration defect of deflected beam is the most serious limiting factor in the performances of micromachining, microminiaturization and high resolution scanning electron microscopes. From many investigators' results, it is obvious that three important compensation methods to aberrations exist in principle, i.e., double deflection system, dynamical focusing, and the dynamical correction using a stigmator. In this paper, based on the aberration formula derived from the eikonal or the path method, the practical data of the aberration constants of deflected electron beam for the sequential deflection system with parallel plates are calculated, and using its result, the distorted spot patterns of an electron probe deflected in two-dimensional directions for various defocusings are graphically displayed by the aid of a computer. Further, by means of the dynamical focusing with a stigmator, the conditions to completely compensate the second order astigmatic aberration are derived, and spot patterns and the electron density distributions within the spots in the case when the compensating conditions are satisfied are also graphically displayed. (Wakatsuki, Y.)

  2. Simulating and visualizing deflections of a remote handling mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Saarinen, Hannu, E-mail: hannu.saarinen@vtt.fi [VTT, Technical Research Centre of Finland, Tekniikankatu 1, 33720 Tampere (Finland); Hämäläinen, Vesa; Karjalainen, Jaakko; Määttä, Timo; Siuko, Mikko [VTT, Technical Research Centre of Finland, Tekniikankatu 1, 33720 Tampere (Finland); Esqué, Salvador [Fusion for Energy, Torres Diagonal Litoral B3, Josep Pla 2, 08019 Barcelona (Spain); Hamilton, David [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2013-10-15

    Highlights: ► An infinitesimal transformation represents elastic deflections. ► Equivalent spring factor is used to combine several deformations. ► Initial VR model accuracy improved from 80 to 5 mm. ► The deflection model is capable of adapting to changes in load at the end-effector. ► The algorithms and approach described are generic and can be adopted for other mechanisms. -- Abstract: Continuing ITER divertor second cassette (SC) remote handling (RH) test campaign has been carried out at divertor test platform (DTP2) in Finland. One of the goals has been to develop and implement efficient algorithms and software tools for simulating and visualizing for the operator the non-instrumented deflections of the RH mechanisms under loading conditions. Based on assumptions of the classical beam theory, the presented solution suggests utilization of an infinitesimal transformation to represent elastic deflections in a mechanical structure. Both structural analysis and measurements of the real structure are utilised during the process. The solution suggests one possible implementation strategy of a software component called structural simulator (SS), which is a software component of the remote handling control system (RHCS) architectural model specified by ITER organisation. Utilisation of the proposed SS necessitates modification of the initial virtual reality (VR) model of RH equipment to a format, which can visually represent the structural deflections. In practise this means adding virtual joints into the model. This will improve the accuracy of the VR visualization and will ensure that the virtual representation of the RH equipment closely aligns with the actual RH equipment. Cassette multifunctional mover (CMM) and second cassette end effector (SCEE) carrying SC were selected to be the initial target system for developing the approach. Demonstrations proved that the approach used can give high levels of accuracy even in complex structures such as the CMM

  3. Simulating and visualizing deflections of a remote handling mechanism

    International Nuclear Information System (INIS)

    Saarinen, Hannu; Hämäläinen, Vesa; Karjalainen, Jaakko; Määttä, Timo; Siuko, Mikko; Esqué, Salvador; Hamilton, David

    2013-01-01

    Highlights: ► An infinitesimal transformation represents elastic deflections. ► Equivalent spring factor is used to combine several deformations. ► Initial VR model accuracy improved from 80 to 5 mm. ► The deflection model is capable of adapting to changes in load at the end-effector. ► The algorithms and approach described are generic and can be adopted for other mechanisms. -- Abstract: Continuing ITER divertor second cassette (SC) remote handling (RH) test campaign has been carried out at divertor test platform (DTP2) in Finland. One of the goals has been to develop and implement efficient algorithms and software tools for simulating and visualizing for the operator the non-instrumented deflections of the RH mechanisms under loading conditions. Based on assumptions of the classical beam theory, the presented solution suggests utilization of an infinitesimal transformation to represent elastic deflections in a mechanical structure. Both structural analysis and measurements of the real structure are utilised during the process. The solution suggests one possible implementation strategy of a software component called structural simulator (SS), which is a software component of the remote handling control system (RHCS) architectural model specified by ITER organisation. Utilisation of the proposed SS necessitates modification of the initial virtual reality (VR) model of RH equipment to a format, which can visually represent the structural deflections. In practise this means adding virtual joints into the model. This will improve the accuracy of the VR visualization and will ensure that the virtual representation of the RH equipment closely aligns with the actual RH equipment. Cassette multifunctional mover (CMM) and second cassette end effector (SCEE) carrying SC were selected to be the initial target system for developing the approach. Demonstrations proved that the approach used can give high levels of accuracy even in complex structures such as the CMM

  4. Nonlinear core deflection in injection molding

    Science.gov (United States)

    Poungthong, P.; Giacomin, A. J.; Saengow, C.; Kolitawong, C.; Liao, H.-C.; Tseng, S.-C.

    2018-05-01

    Injection molding of thin slender parts is often complicated by core deflection. This deflection is caused by molten plastics race tracking through the slit between the core and the rigid cavity wall. The pressure of this liquid exerts a lateral force of the slender core causing the core to bend, and this bending is governed by a nonlinear fifth order ordinary differential equation for the deflection that is not directly in the position along the core. Here we subject this differential equation to 6 sets of boundary conditions, corresponding to 6 commercial core constraints. For each such set of boundary conditions, we develop an explicit approximate analytical solution, including both a linear term and a nonlinear term. By comparison with finite difference solutions, we find our new analytical solutions to be accurate. We then use these solutions to derive explicit analytical approximations for maximum deflections and for the core position of these maximum deflections. Our experiments on the base-gated free-tip boundary condition agree closely with our new explicit approximate analytical solution.

  5. Review of the helicity formalism

    International Nuclear Information System (INIS)

    Barreiro, F.; Cerrada, M.; Fernandez, E.

    1972-01-01

    Our purpose in these notes has been to present a brief and general review of the helicity formalism. We begin by discussing Lorentz invariance, spin and helicity ideas, in section 1 . In section 2 we deal with the construction of relativistic states and scattering amplitudes in the helicity basis and we study their transformation properties under discrete symmetries. Finally we present some more sophisticated topics like kinematical singularities of helicity amplitudes, kinematical constraints and crossing relations 3, 4, 5 respectively. (Author) 8 refs

  6. Helical Confinement Concepts

    Energy Technology Data Exchange (ETDEWEB)

    Beidler, C; Brakel, R; Burhenn, R; Dinklage, A; Erckmann, V; Feng, Y; Geiger, J; Hartmann, D; Hirsch, M; Jaenicke, R; Koenig, R; Laqua, H P; Maassberg, H; Wagner, F; Weller, A; Wobig, H [Max-Planck Institut fuer Plasmaphysik, EURATOM Association, Greifswald (Germany)

    2012-09-15

    Stellarators, conceived 1951 by Lyman Spitzer in Princeton, are toroidal devices that confine a plasma in a magnetic field which originates from currents in coils outside the plasma. A plasma current driven by external means, for example by an ohmic transformer, is not required for confinement. Supplying the desired poloidal field component by external coils leads to a helically structured plasma topology. Thus stellarators - or helical confinement devices - are fully three-dimensional in contrast to the toroidal (rotational) symmetry of tokamaks. As stellarators can be free of an inductive current, whose radial distribution depends on the plasma parameters, their equilibrium must not be established via the evolving plasma itself, but to a first order already given by the vacuum magnetic field. They do not need an active control (like positional feedback) and therefore cannot suffer from its failure. The outstanding conceptual advantage of stellarators is the potential of steady state plasma operation without current drive. As there is no need for current drive, the recirculating power is expected to be smaller than in equivalent tokamaks. The lack of a net current avoids current driven instabilities; specifically, no disruptions, no resistive wall modes and no conventional or neoclassical tearing modes appear. Second order pressure-driven currents (Pfirsch-Schlueter, bootstrap) exist but they can be modified and even minimized by the magnetic design. The magnetic configuration of helical devices naturally possesses a separatrix, which allows the implementation of a helically structured divertor for exhaust and impurity control. (author)

  7. Helical Polyacetylenes Induced via Noncovalent Chiral Interactions and Their Applications as Chiral Materials.

    Science.gov (United States)

    Maeda, Katsuhiro; Yashima, Eiji

    2017-08-01

    Construction of predominantly one-handed helical polyacetylenes with a desired helix sense utilizing noncovalent chiral interactions with nonracemic chiral guest compounds based on a supramolecular approach is described. As with the conventional dynamic helical polymers possessing optically active pendant groups covalently bonded to the polymer chains, this noncovalent helicity induction system can show significant chiral amplification phenomena, in which the chiral information of the nonracemic guests can transfer with high cooperativity through noncovalent bonding interactions to induce an almost single-handed helical conformation in the polymer backbone. An intriguing "memory effect" of the induced macromolecular helicity is observed for some polyacetylenes, which means that the helical conformations induced in dynamic helical polyacetylene can be transformed into metastable static ones by tuning their helix-inversion barriers. Potential applications of helical polyacetylenes with controlled helix sense constructed by the "noncovalent helicity induction and/or memory effect" as chiral materials are also described.

  8. Brachytherapy needle deflection evaluation and correction

    International Nuclear Information System (INIS)

    Wan Gang; Wei Zhouping; Gardi, Lori; Downey, Donal B.; Fenster, Aaron

    2005-01-01

    In prostate brachytherapy, an 18-gauge needle is used to implant radioactive seeds. This thin needle can be deflected from the preplanned trajectory in the prostate, potentially resulting in a suboptimum dose pattern and at times requiring repeated needle insertion to achieve optimal dosimetry. In this paper, we report on the evaluation of brachytherapy needle deflection and bending in test phantoms and two approaches to overcome the problem. First we tested the relationship between needle deflection and insertion depth as well as whether needle bending occurred. Targeting accuracy was tested by inserting a brachytherapy needle to target 16 points in chicken tissue phantoms. By implanting dummy seeds into chicken tissue phantoms under 3D ultrasound guidance, the overall accuracy of seed implantation was determined. We evaluated methods to overcome brachytherapy needle deflection with three different insertion methods: constant orientation, constant rotation, and orientation reversal at half of the insertion depth. Our results showed that needle deflection is linear with needle insertion depth, and that no noticeable bending occurs with needle insertion into the tissue and agar phantoms. A 3D principal component analysis was performed to obtain the population distribution of needle tip and seed position relative to the target positions. Our results showed that with the constant orientation insertion method, the mean needle targeting error was 2.8 mm and the mean seed implantation error was 2.9 mm. Using the constant rotation and orientation reversal at half insertion depth methods, the deflection error was reduced. The mean needle targeting errors were 0.8 and 1.2 mm for the constant rotation and orientation reversal methods, respectively, and the seed implantation errors were 0.9 and 1.5 mm for constant rotation insertion and orientation reversal methods, respectively

  9. Deflection of massive neutrinos by gravitational fields

    International Nuclear Information System (INIS)

    Fargion, D.

    1981-01-01

    The curvature undergone by massive neutrino trajectories, passing by a mass M at a distance b from the center of a body, is examined. Calculations led to the following angle of deflection: δ rho = 2GM/b#betta# 2 sub(infinity)C 2 (1 + #betta# 2 sub(infinity)), where #betta#sub(infinity) is the dimensionless velocity of the particle at infinity. The ultrarelativistic limit (#betta#sub(infinity) = 1) coincides with the usual massless deflection. Physical consequences are considered. (author)

  10. Equilibrium calculations for helical axis stellarators

    International Nuclear Information System (INIS)

    Hender, T.C.; Carreras, B.A.

    1984-04-01

    An average method based on a vacuum flux coordinate system is presented. This average method permits the study of helical axis stellarators with toroidally dominated shifts. An ordering is introduced, and to lowest order the toroidally averaged equilibrium equations are reduced to a Grad-Shafranov equation. Also, to lowest order, a Poisson-type equation is obtained for the toroidally varying corrections to the equilibium. By including these corrections, systems that are toroidally dominated, but with significant helical distortion to the equilibrium, may be studied. Numerical solutions of the average method equations are shown to agree well with three-dimensional calculations

  11. Helical axial injection concept for cyclotrons

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, E.D.

    1981-01-01

    A concept for an external beam injection system using a helical beam path centered on the cyclotron axis is described. This system could be used to couple two accelerator stages, with or without intermediate stripping, in cases where conventional axial injection or radial injection are not practical.

  12. Helical axial injection concept for cyclotrons

    International Nuclear Information System (INIS)

    Hudson, E.D.

    1981-01-01

    A concept for an external beam injection system using a helical beam path centered on the cyclotron axis is described. This system could be used to couple two accelerator stages, with or without intermediate stripping, in cases where conventional axial injection or radial injection are not practical

  13. Low-energy properties of fractional helical Luttinger liquids

    NARCIS (Netherlands)

    Meng, T.; Fritz, L.|info:eu-repo/dai/nl/371569559; Schuricht, D.|info:eu-repo/dai/nl/369284690; Loss, D.

    2014-01-01

    We investigate the low-energy properties of (quasi) helical and fractional helical Luttinger liquids. In particular, we calculate the Drude peak of the optical conductivity, the density of states, as well as charge transport properties of the interacting system with and without attached Fermi liquid

  14. Optical forces through guided light deflections

    DEFF Research Database (Denmark)

    Palima, Darwin; Bañas, Andrew Rafael; Vizsnyiczai, Gaszton

    2013-01-01

    . In this work we look into the object shaping aspect and its potential for controlled optical manipulation. Using a simple bent waveguide as example, our numerical simulations show that the guided deflection of light efficiently converts incident light momentum into optical force with one order...

  15. Particle beam and crabbing and deflecting structure

    Science.gov (United States)

    Delayen, Jean [Yorktown, VA

    2011-02-08

    A new type of structure for the deflection and crabbing of particle bunches in particle accelerators comprising a number of parallel transverse electromagnetic (TEM)-resonant) lines operating in opposite phase from each other. Such a structure is significantly more compact than conventional crabbing cavities operating the transverse magnetic TM mode, thus allowing low frequency designs.

  16. Determining large deflections in rectangular combined loaded ...

    Indian Academy of Sciences (India)

    (Bisshopp & Drucker 1945; Scott et al 1955; Lau 1982; Rao & Rao 1986; Baker 1993; Lee et al 1993; Frisch-Fay 1962; Fertis 1999). Prathap and Varadan (1976) had calculated large deflections in cantilever beams made of non-linear Ramberg–Osgood type material on which concentrated load effected on the free end.

  17. Coulomb double helical structure

    Science.gov (United States)

    Kamimura, Tetsuo; Ishihara, Osamu

    2012-01-01

    Structures of Coulomb clusters formed by dust particles in a plasma are studied by numerical simulation. Our study reveals the presence of various types of self-organized structures of a cluster confined in a prolate spheroidal electrostatic potential. The stable configurations depend on a prolateness parameter for the confining potential as well as on the number of dust particles in a cluster. One-dimensional string, two-dimensional zigzag structure and three-dimensional double helical structure are found as a result of the transition controlled by the prolateness parameter. The formation of stable double helical structures resulted from the transition associated with the instability of angular perturbations on double strings. Analytical perturbation study supports the findings of numerical simulations.

  18. Helically linked mirror arrangement

    International Nuclear Information System (INIS)

    Ranjan, P.

    1986-08-01

    A scheme is described for helical linking of mirror sections, which endeavors to combine the better features of toroidal and mirror devices by eliminating the longitudinal loss of mirror machines, having moderately high average β and steady state operation. This scheme is aimed at a device, with closed magnetic surfaces having rotational transform for equilibrium, one or more axisymmetric straight sections for reduced radial loss, a simple geometrical axis for the links and an overall positive magnetic well depth for stability. We start by describing several other attempts at linking of mirror sections, made both in the past and the present. Then a description of our helically linked mirror scheme is given. This example has three identical straight sections connected by three sections having helical geometric axes. A theoretical analysis of the magnetic field and single-particle orbits in them leads to the conclusion that most of the passing particles would be confined in the device and they would have orbits independent of pitch angle under certain conditions. Numerical results are presented, which agree well with the theoretical results as far as passing particle orbits are concerned

  19. Roles of effective helical ripple rates in nonlinear stability of externally induced magnetic islands

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Seiya, E-mail: n-seiya@kobe-kosen.ac.jp [Kobe City College of Technology, Kobe, Hyogo 651-2194 (Japan)

    2015-02-15

    Magnetic islands are externally produced by resonant magnetic perturbations (RMPs) in toroidal plasmas. Spontaneous annihilation of RMP-induced magnetic islands called self-healing has been observed in helical systems. A possible mechanism of the self-healing is shielding of RMP penetration by helical ripple-induced neoclassical flows, which give rise to neoclassical viscous torques. In this study, effective helical ripple rates in multi-helicity helical systems are revisited, and a multi-helicity effect on the self-healing is investigated, based on a theoretical model of rotating magnetic islands. It is confirmed that effective helical ripple rates are sensitive to magnetic axis positions. It is newly found that self-healing thresholds also strongly depend on magnetic axis positions, which is due to dependence of neoclassical viscous torques on effective helical ripple rates.

  20. Stimuli-Directed Helical Chirality Inversion and Bio-Applications

    Directory of Open Access Journals (Sweden)

    Ziyu Lv

    2016-08-01

    Full Text Available Helical structure is a sophisticated ubiquitous motif found in nature, in artificial polymers, and in supramolecular assemblies from microscopic to macroscopic points of view. Significant progress has been made in the synthesis and structural elucidation of helical polymers, nevertheless, a new direction for helical polymeric materials, is how to design smart systems with controllable helical chirality, and further use them to develop chiral functional materials and promote their applications in biology, biochemistry, medicine, and nanotechnology fields. This review summarizes the recent progress in the development of high-performance systems with tunable helical chirality on receiving external stimuli and discusses advances in their applications as drug delivery vesicles, sensors, molecular switches, and liquid crystals. Challenges and opportunities in this emerging area are also presented in the conclusion.

  1. Electron image reconstruction of helical protein assemblies

    International Nuclear Information System (INIS)

    Cremers, A.F.M.

    1980-01-01

    The analysis of projections of large ordered biological systems obtained by electron microscopy of negatively stained specimens is described. The biological structures amenable to this approach are constructed from a large number of identical protein molecules, which are arranged according to helical symmetry. Electron images of these structures generally contain sufficient information in order to calculate a three-dimensional density map. (Auth.)

  2. UWB Wind Turbine Blade Deflection Sensing for Wind Energy Cost Reduction.

    Science.gov (United States)

    Zhang, Shuai; Jensen, Tobias Lindstrøm; Franek, Ondrej; Eggers, Patrick C F; Olesen, Kim; Byskov, Claus; Pedersen, Gert Frølund

    2015-08-12

    A new application of utilizing ultra-wideband (UWB) technology to sense wind turbine blade deflections is introduced in this paper for wind energy cost reduction. The lower UWB band of 3.1-5.3 GHz is applied. On each blade, there will be one UWB blade deflection sensing system, which consists of two UWB antennas at the blade root and one UWB antenna at the blade tip. The detailed topology and challenges of this deflection sensing system are addressed. Due to the complexity of the problem, this paper will first realize the on-blade UWB radio link in the simplest case, where the tip antenna is situated outside (and on the surface of) a blade tip. To investigate this case, full-blade time-domain measurements are designed and conducted under different deflections. The detailed measurement setups and results are provided. If the root and tip antenna locations are properly selected, the first pulse is always of sufficient quality for accurate estimations under different deflections. The measured results reveal that the blade tip-root distance and blade deflection can be accurately estimated in the complicated and lossy wireless channels around a wind turbine blade. Some future research topics on this application are listed finally.

  3. Turbulent Helicity in the Atmospheric Boundary Layer

    Science.gov (United States)

    Chkhetiani, Otto G.; Kurgansky, Michael V.; Vazaeva, Natalia V.

    2018-05-01

    We consider the assumption postulated by Deusebio and Lindborg (J Fluid Mech 755:654-671, 2014) that the helicity injected into the Ekman boundary layer undergoes a cascade, with preservation of its sign (right- or alternatively left-handedness), which is a signature of the system rotation, from large to small scales, down to the Kolmogorov microscale of turbulence. At the same time, recent direct field measurements of turbulent helicity in the steppe region of southern Russia near Tsimlyansk Reservoir show the opposite sign of helicity from that expected. A possible explanation for this phenomenon may be the joint action of different scales of atmospheric flows within the boundary layer, including the sea-breeze circulation over the test site. In this regard, we consider a superposition of the classic Ekman spiral solution and Prandtl's jet-like slope-wind profile to describe the planetary boundary-layer wind structure. The latter solution mimics a hydrostatic shallow breeze circulation over a non-uniformly heated surface. A 180°-wide sector on the hodograph plane exists, within which the relative orientation of the Ekman and Prandtl velocity profiles favours the left rotation with height of the resulting wind velocity vector in the lowermost part of the boundary layer. This explains the negative (left-handed) helicity cascade toward small-scale turbulent motions, which agrees with the direct field measurements of turbulent helicity in Tsimlyansk. A simple turbulent relaxation model is proposed that explains the measured positive values of the relatively minor contribution to turbulent helicity from the vertical components of velocity and vorticity.

  4. Dark matter prospects in deflected mirage mediation

    International Nuclear Information System (INIS)

    Holmes, Michael; Nelson, Brent D.

    2009-01-01

    The recently introduced deflected mirage mediation (DMM) model is a string-motivated paradigm in which all three of the major supersymmetry-breaking transmission mechanisms are operative. We begin a systematic exploration of the parameter space of this rich model context, paying special attention to the pattern of gaugino masses which arise. In this work we focus on the dark matter phenomenology of the DMM model as such signals are the least influenced by the model-dependent scalar masses. We find that a large portion of the parameter space in which the three mediation mechanisms have a similar effective mass scale of 1 TeV or less will be probed by future direct and indirect detection experiments. Distinguishing deflected mirage mediation from the mirage model without gauge mediation will prove difficult without collider input, though we indicate how gamma ray signals may provide an opportunity for distinguishing between the two paradigms

  5. Deflection evaluation using time-resolved radiography

    International Nuclear Information System (INIS)

    Fry, D.A.; Lucero, J.P.

    1990-01-01

    Time-resolved radiography is the creation of an x-ray image for which both the start-exposure and stop-exposure times are known with respect to the event under study. The combination of image and timing are used to derive information about the event. The authors have applied time-resolved radiography to evaluate motions of explosive-driven events. In the particular application discussed in this paper, the author's intent is to measure maximum deflections of the components involved. Exposures are made during the time just before to just after the event of interest occurs. A smear or blur of motion out to its furthest extent is recorded on the image. Comparison of the dynamic images with static images allows deflection measurements to be made

  6. Helical modes generate antimagnetic rotational spectra in nuclei

    Science.gov (United States)

    Malik, Sham S.

    2018-03-01

    A systematic analysis of the antimagnetic rotation band using r -helicity formalism is carried out for the first time. The observed octupole correlation in a nucleus is likely to play a role in establishing the antimagnetic spectrum. Such octupole correlations are explained within the helical orbits. In a rotating field, two identical fermions (generally protons) with paired spins generate these helical orbits in such a way that its positive (i.e., up) spin along the axis of quantization refers to one helicity (right-handedness) while negative (down) spin along the same quantization-axis decides another helicity (left-handedness). Since the helicity remains invariant under rotation, therefore, the quantum state of a fermion is represented by definite angular momentum and helicity. These helicity represented states support a pear-shaped structure of a rotating system having z axis as the symmetry axis. A combined operation of parity, time-reversal, and signature symmetries ensures an absence of one of the signature partner band from the observed antimagnetic spectrum. This formalism has also been tested for the recently observed negative parity Δ I =2 antimagnetic spectrum in odd-A 101Pd nucleus and explains nicely its energy spectrum as well as the B (E 2 ) values. Further, this formalism is found to be fully consistent with twin-shears mechanism popularly known for such type of rotational bands. It also provides significant clue for extending these experiments in various mass regions spread over the nuclear chart.

  7. The effect of ligation on the load deflection characteristics of nickel titanium orthodontic wire.

    Science.gov (United States)

    Kasuya, Shugo; Nagasaka, Satoshi; Hanyuda, Ai; Ishimura, Sadao; Hirashita, Ayao

    2007-12-01

    This study examined the effect of ligation on the load-deflection characteristics of nickel-titanium (NiTi) orthodontic wire. A modified three-point bending system was used for bending the NiTi round wire, which was inserted and ligated in the slots of three brackets, one of which was bonded to each of the three bender rods. Three different ligation methods, stainless steel ligature (SSL), slot lid (SL), and elastomeric ligature (EL), were employed, as well as a control with neither bracket nor ligation (NBL). The tests were repeated five times under each condition. Comparisons were made of load-deflection curve, load at maximum deflection of 2,000 microm, and load at a deflection of 1,500 microm during unloading. Analysis of Variance (ANOVA) and Dunnett's test were conducted to determine method difference (alpha = 0.05). The interaction between deflection and ligation was tested, using repeated-measures ANOVA (alpha = 0.05). The load values of the ligation groups were two to three times greater than the NBL group at a deflection of 1,500 microm during unloading: 4.37 N for EL, 3.90 N for SSL, 3.02 N for SL, and 1.49 N for NBL (P wire may make NiTi wire exhibit a significantly heavier load than that traditionally expected. NiTi wire exhibited the majority of its true superelasticity with SL, whereas EL may act as a restraint on its superelasticity.

  8. Distribution of flexural deflection in the worldwide outer rise area

    Science.gov (United States)

    Lin, Zi-Jun; Lin, Jing-Yi; Lin, Yi-Chin; Chin, Shao-Jinn; Chen, Yen-Fu

    2015-04-01

    The outer rise on the fringe of a subduction system is caused by an accreted load on the flexed oceanic lithosphere. The magnitude of the deflection is usually linked to the stress state beard by the oceanic plate. In a coupled subduction zone, the stress is abundantly accumulated across the plate boundary which should affect the flexural properties of the subducted plate. Thus, the variation of the outer rise in shape may reflect the seismogenic characteristics of the subduction system. In this study, we intent to find the correlation between the flexure deflection (Wb) of the outer rise and the subduction zone properties by comparing several slab parameters and the Wb distribution. The estimation of Wb is performed based on the available bathymetry data and the statistic analysis of earthquakes is from the global ISC earthquake catalog for the period of 1900-2015. Our result shows a progressive change of Wb in space, suggesting a robust calculation. The average Wb of worldwise subduction system spreads from 348 to 682 m. No visible distinction in the ranging of Wb was observed for different subduction zones. However, in a weak coupling subduction system, the standard variation of Wb has generally larger value. Relatively large Wb generally occurs in the center of the trench system, whereas small Wb for the two ends of trench. The comparison of Wb and several slab parameters shows that the Wb may be correlated with the maximal magnitude and the number of earthquakes. Otherwise, no clear relationship with other parameters can be obtained.

  9. PERFORMANCE ANALYSIS OF VCR SYSTEM WITH VARYING THE DIAMETERS OF HELICAL CONDENSER COIL BY USING R-134A REFRIGERANT

    OpenAIRE

    R.Hussain Vali; P.Yagnasri; S.Naresh Kumar Reddy

    2016-01-01

    Vapor compression machine is a refrigerator in which the heat removed from the cold by evaporation of the refrigerant is given a thermal potential so that it can gravitate to a natural sink by compressing the vapor produced. Majority of the refrigerators works on the Vapor compression refrigeration system. The system consists of components like compressor, condenser, expansion valve and evaporator. The performance of the system depends on the performance of all the components of the system. ...

  10. Construction of the Crystal Ball detector system and study of the helicity asymmetry in γp→pπ0π0

    International Nuclear Information System (INIS)

    Krambrich, D.

    2007-01-01

    Since spring 2004 the Crystal Ball Detector has been used for coincidence experiments probing the structure of the nucleons with real photons at the Mainzer Microtron. A major part of the commissioning, which was the first goal of this work, was the development and implementation of a new system for the Crystal Ball electronics. Components were designed or tested and, if necessary, modified to fit the experimental needs. After the commissioning, the set-up was then used successfully in several pion and eta production experiments for more than 2500 hours of beamtime. The second focus of this dissertation is the first measurement of the beam helicity asymmetry I s un in photoproduction of two neutral pions. The understanding of the excitation spectra of the nucleon requires experiments using polarised photons and/or polarised targets. Models based on different assumptions do reproduce the quantities measured without polarisation equally well but differ in the prediction of polarisation observables. The determination of more sensitive quantities is therefore mandatory. In contrast to single meson production, an observable appears in double pion production when using circularly polarized photons incident on an unpolarized target. This observable was determined as a function of energy and angle in the reactions γ p → p π 0 π 0 and in γ p → p π + π - . The results differ significantly from the model predictions. (orig.)

  11. Employing Helicity Amplitudes for Resummation

    NARCIS (Netherlands)

    Moult, I.; Stewart, I.W.; Tackmann, F.J.; Waalewijn, W.J.

    2015-01-01

    Many state-of-the-art QCD calculations for multileg processes use helicity amplitudes as their fundamental ingredients. We construct a simple and easy-to-use helicity operator basis in soft-collinear effective theory (SCET), for which the hard Wilson coefficients from matching QCD onto SCET are

  12. μtrack profiles for investigating side effects of advanced silicon heads for helical scan tape systems

    NARCIS (Netherlands)

    Hozoi, A.; Groenland, J.P.J.; Lodder, J.C.; Albertini, J.B.

    2002-01-01

    Track and μtrack scans are common techniques in hard disk systems for investigating side writing and side reading, and for characterizing the response of MR read heads. These methods are implemented less in tape systems, where the contact recording mode and flexible medium make it difficult to

  13. MAGNETIC HELICITY FLUX IN THE PRESENCE OF SHEAR

    International Nuclear Information System (INIS)

    Hubbard, Alexander; Brandenburg, Axel

    2011-01-01

    Magnetic helicity has risen to be a major player in dynamo theory, with the helicity of the small-scale field being linked to the dynamo saturation process for the large-scale field. It is a nearly conserved quantity, which allows its evolution equation to be written in terms of production and flux terms. The flux term can be decomposed in a variety of fashions. One particular contribution that has been expected to play a significant role in dynamos in the presence of mean shear was isolated by Vishniac and Cho. Magnetic helicity fluxes are explicitly gauge dependent however, and the correlations that have come to be called the Vishniac-Cho flux were determined in the Coulomb gauge, which turns out to be fraught with complications in shearing systems. While the fluxes of small-scale helicity are explicitly gauge dependent, their divergences can be gauge independent. We use this property to investigate magnetic helicity fluxes of the small-scale field through direct numerical simulations in a shearing-box system and find that in a numerically usable gauge the divergence of the small-scale helicity flux vanishes, while the divergence of the Vishniac-Cho flux remains finite. We attribute this seeming contradiction to the existence of horizontal fluxes of small-scale magnetic helicity with finite divergences.

  14. Magnetic Helicity Flux in the Presence of Shear

    Science.gov (United States)

    Hubbard, Alexander; Brandenburg, Axel

    2011-01-01

    Magnetic helicity has risen to be a major player in dynamo theory, with the helicity of the small-scale field being linked to the dynamo saturation process for the large-scale field. It is a nearly conserved quantity, which allows its evolution equation to be written in terms of production and flux terms. The flux term can be decomposed in a variety of fashions. One particular contribution that has been expected to play a significant role in dynamos in the presence of mean shear was isolated by Vishniac & Cho. Magnetic helicity fluxes are explicitly gauge dependent however, and the correlations that have come to be called the Vishniac-Cho flux were determined in the Coulomb gauge, which turns out to be fraught with complications in shearing systems. While the fluxes of small-scale helicity are explicitly gauge dependent, their divergences can be gauge independent. We use this property to investigate magnetic helicity fluxes of the small-scale field through direct numerical simulations in a shearing-box system and find that in a numerically usable gauge the divergence of the small-scale helicity flux vanishes, while the divergence of the Vishniac-Cho flux remains finite. We attribute this seeming contradiction to the existence of horizontal fluxes of small-scale magnetic helicity with finite divergences.

  15. Flexible helical yarn swimmers.

    Science.gov (United States)

    Zakharov, A P; Leshansky, A M; Pismen, L M

    2016-09-01

    We investigate the motion of a flexible Stokesian flagellar swimmer realised as a yarn made of two intertwined elastomer fibres, one active, that can reversibly change its length in response to a local excitation causing transition to the nematic state or swelling, and the other one, a passive isotropic elastomer with identical mechanical properties. A propagating chemical wave may provide an excitation mechanism ensuring a constant length of the excited region. Generally, the swimmer moves along a helical trajectory, and the propagation and rotation velocity are very sensitive to the ratio of the excited region to the pitch of the yarn, as well as to the size of a carried load. External excitation by a moving actuating beam is less effective, unless the direction of the beam is adjusted to rotation of the swimmer.

  16. Introduction of fuzzy logic theorem for quench detection in the superconducting coil system of a Large Helical Device

    International Nuclear Information System (INIS)

    Adachi, Yamato; Ninomiya, Akira; Uriu, Yoshihisa; Ishigohka, Takeshi; Mito, Toshiyuki; Imagawa, Shinsaku; Yanagi, Nagato; Sekiguchi, Haruo; Yamada, Shuichi

    2005-01-01

    We have analyzed the state of the superconducting coil system in a LHD at NIFS (National Institute of Fusion Science) using a fuzzy logic theorem to detect quenching at an early stage. In this method, the 'warning coefficient' of the coil system is calculated. As for the fuzzy variables, 'effective stored heat' in the coil is introduced in addition to the voltage signal in order to improve quench detection and state estimation. The 'effective stored heat' is an integrated value of the heat generated in the coil on the assumption that instantaneous heat in the conductor is continuously cooled by liquid helium. Experiments conducted using the LHD coils confirmed that quench alarm signals can be issued with sufficient lead time before quenching. On the other hand, in the case of small local disturbances, the system shows only a small increase in the caution level. (author)

  17. A study of topological quantum phase transition and Majorana localization length for the interacting helical liquid system

    International Nuclear Information System (INIS)

    Dey, Dayasindhu; Saha, Sudip Kumar; Deo, P. Singha; Kumar, Manoranjan; Sarkar, Sujit

    2017-01-01

    We study the topological quantum phase transition and also the nature of this transition using the density matrix renormalization group method. We observe the existence of topological quantum phase transition for repulsive interaction, however this phase is more stable for the attractive interaction. The length scale dependent study shows many new and important results and we show explicitly that the major contribution to the excitation comes from the edge of the system when the system is in the topological state. We also show the dependence of Majorana localization length for various values of chemical potential. (author)

  18. Topology of modified helical gears and Tooth Contact Analysis (TCA) program

    Science.gov (United States)

    Litvin, Faydor L.; Zhang, Jiao

    1989-01-01

    The contents of this report covers: (1) development of optimal geometries for crowned helical gears; (2) a method for their generation; (3) tooth contact analysis (TCA) computer programs for the analysis of meshing and bearing contact of the crowned helical gears; and (4) modelling and simulation of gear shaft deflection. The developed method for synthesis was used to determine the optimal geometry for a crowned helical pinion surface and was directed to localize the bearing contact and guarantee favorable shape and a low level of transmission errors. Two new methods for generation of the crowned helical pinion surface are proposed. One is based on the application of a tool with a surface of revolution that slightly deviates from a regular cone surface. The tool can be used as a grinding wheel or as a shaver. The other is based on a crowning pinion tooth surface with predesigned transmission errors. The pinion tooth surface can be generated by a computer-controlled automatic grinding machine. The TCA program simulates the meshing and bearing contact of the misaligned gears. The transmission errors are also determined. The gear shaft deformation was modelled and investigated. It was found that the deflection of gear shafts has the same effect as gear misalignment.

  19. Characterisation of a Mechanical Deflection Sensor

    CSIR Research Space (South Africa)

    Miyambo, M

    2012-10-01

    Full Text Available Mechanical Defl ection Sensor M MIYAMBO AND T PANDELANI CSIR Defence, Peace, Safety and Security, PO Box 395, Pretoria, South Africa, 0001 Email: mmiyambo@csir.co.za ? www.csir.co.za INTRODUCTION The CSIR Defence, Peace, Safety and Security (DPSS...-time duration, which is integrated over time to provide the total measured impulse of a shallow-buried explosive charge near-field blast (Snyman et al, 2006). The Mechanical Deflection Sensor (MDS) was developed by the CSIR LS, in conjunction with Conical...

  20. Development of electron beam deflection circuit

    International Nuclear Information System (INIS)

    Leo Kwee Wah; Lojius Lombigit; Abu Bakar Ghazali; Azaman

    2007-01-01

    This paper describes a development of a power supply circuit to deflect and move the electron beam across the window of the Baby electron beam machine. It comprises a discussion of circuit design, its assembly and the test results. A variety of input and output conditions have been tested and it was found that the design is capable to supply 1.0 A with 50Hz on X-axis coil and 0.4A with 500Hz on Y-axis coil. (Author)

  1. NSF tandem stack support structure deflection characteristics

    International Nuclear Information System (INIS)

    Cook, J.

    1979-12-01

    Results are reported of load tests carried out on the glass legs of the insulating stack of the 30 MV tandem Van de Graaff accelerator now under construction at Daresbury Laboratory. The tests to investigate the vulnerability of the legs when subjected to tensile stresses were designed to; establish the angle of rotation of the pads from which the stresses in the glass legs may be calculated, proof-test the structure and at the same time reveal any asymmetry in pad rotations or deflections, and to confirm the validity of the computer design analysis. (UK)

  2. Hot Flow Anomaly formation by magnetic deflection

    International Nuclear Information System (INIS)

    Onsager, T.G.; Thomsen, M.F.; Winske, D.

    1990-01-01

    Hot Flow Anomalies (HFAs) are localized plasma structures observed in the solar wind and magnetosheath near the Earth's quasi-parallel bow shock. The authors present 1-D hybrid computer simulations illustrating a formation mechanism for HFAs in which the single, hot, ion population results from a spatial separation of two counterstreaming ion beams. The higher-density, cooler regions are dominated by the background (solar wind) ions, and the lower-density, hotter, internal regions are dominated by the beam ions. The spatial separation of the beam and background is caused by the deflection of the ions in large amplitude magnetic fields which are generated by ion/ion streaming instabilities

  3. Optical beam deflection sensor: design and experiments.

    Science.gov (United States)

    Sakamoto, João M S; Marques, Renan B; Kitano, Cláudio; Rodrigues, Nicolau A S; Riva, Rudimar

    2017-10-01

    In this work, we present a double-pass optical beam deflection sensor and its optical design method. To accomplish that, a mathematical model was proposed and computational simulations were performed, in order to obtain the sensor's characteristic curves and to analyze its behavior as function of design parameters. The mathematical model was validated by comparison with the characteristic curves acquired experimentally. The sensor was employed to detect acoustic pulses generated by a pulsed laser in a sample surface, in order to show its potential for monitoring applications handling high energy input as laser welding or laser ablation.

  4. Photothermal deflection spectroscopy investigations of uranium electrochemistry

    International Nuclear Information System (INIS)

    Russo, R.E.; Rudnicki, J.D.

    1993-01-01

    Photothermal Deflection Spectroscopy (PDS) has been successfully applied to the study of uranium oxide electrochemistry. A brief description of PDS and preliminary results that demonstrate the technique are presented. Concentration gradients formed at the electrode surface are measured by this technique. The gradients give insight into the reaction mechanisms. There is some evidence of the initiation of non-electrochemical dissolution of the uranium oxide. Optical absorption by the uranium oxide is measured by PDS and the first results indicate that the absorption of the surface does not change during electrochemical experiments. This result is contrary to literature measurements of bulk samples that indicate that the optical absorption should be strongly changing

  5. High-n helicity-induced shear Alfven eigenmodes

    International Nuclear Information System (INIS)

    Nakajima, N.; Cheng, C.Z.; Okamoto, M.

    1992-05-01

    The high-n Helicity-induced shear Alfven Eigenmodes (HAE) are considered both analytically and numerically for the straight helical magnetic system, where n is the toroidal mode number. The eigenmode equation for the high-n HAE modes is derived along the field line and with the aid of the averaging method is shown to reduce to the Mathieu equation asymptotically. The discrete HAE modes are shown to exist inside the continuum spectrum gaps. The continuous spectrum gaps appear around ω 2 = ω A 2 [N(lι-m)/2] 2 for N = 1,2,.., where ω A is the toroidal Alfven transit frequency, and l, m, and ι are the polarity of helical coils, the toroidal pitch number of helical coils, and the rotational transform, respectively. For the same ω A and ι, the frequency of the helical continuum gap is larger than that of the continuum gap in tokamak plasmas by |l-ι -1 m|. The polarity of helical coils l plays a crucial role in determining the spectrum gaps and the properties of the high-n HAE modes. The spectrum gaps near the magnetic axis are created by the helical ripple with circular flux surfaces for l = 1, and ≥ 3 helicals. For l = 2 helical systems, the spectrum gaps are created by the ellipticity of the flux surfaces. These analytical results for the continuum gaps and the existence of the high-n HAE modes in the continuum gaps are confirmed numerically for the l = 2 case, and we find that the HAE modes exist for mode structures with the even and the odd parities. (author)

  6. Magnetic Helicities and Dynamo Action in Magneto-rotational Turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Bodo, G.; Rossi, P. [INAF/Osservatorio Astrofisico di Torino, Strada Osservatorio 20, I-10025 Pino Torinese (Italy); Cattaneo, F. [Department of Astronomy and Astrophysics, The University of Chicago, 5640 S. Ellis Avenue, Chicago IL 60637 (United States); Mignone, A., E-mail: bodo@oato.inaf.it [Dipartimento di Fisica, Università degli Studi di Torino, Via Pietro Giuria 1, 10125 Torino (Italy)

    2017-07-10

    We examine the relationship between magnetic flux generation, taken as an indicator of large-scale dynamo action, and magnetic helicity, computed as an integral over the dynamo volume, in a simple dynamo. We consider dynamo action driven by magneto-rotational turbulence (MRT) within the shearing-box approximation. We consider magnetically open boundary conditions that allow a flux of helicity in or out of the computational domain. We circumvent the problem of the lack of gauge invariance in open domains by choosing a particular gauge—the winding gauge—that provides a natural interpretation in terms of the average winding number of pairwise field lines. We use this gauge precisely to define and measure the helicity and the helicity flux for several realizations of dynamo action. We find in these cases that the system as a whole does not break reflectional symmetry and that the total helicity remains small even in cases when substantial magnetic flux is generated. We find no particular connection between the generation of magnetic flux and the helicity or the helicity flux through the boundaries. We suggest that this result may be due to the essentially nonlinear nature of the dynamo processes in MRT.

  7. Modeling and simulations of new electrostatically driven, bimorph actuator for high beam steering micromirror deflection angles

    Science.gov (United States)

    Walton, John P.; Coutu, Ronald A.; Starman, LaVern

    2015-02-01

    There are numerous applications for micromirror arrays seen in our everyday lives. From flat screen televisions and computer monitors, found in nearly every home and office, to advanced military weapon systems and space vehicles, each application bringing with it a unique set of requirements. The microelectromechanical systems (MEMS) industry has researched many ways micromirror actuation can be accomplished and the different constraints on performance each design brings with it. This paper investigates a new "zipper" approach to electrostatically driven micromirrors with the intent of improving duel plane beam steering by coupling large deflection angles, over 30°, and a fast switching speed. To accomplish this, an extreme initial deflection is needed which can be reached using high stress bimorph beams. Currently this requires long beams and high voltage for the electrostatic pull in or slower electrothermal switching. The idea for this "zipper" approach is to stack multiple beams of a much shorter length and allow for the deflection of each beam to be added together in order to reach the required initial deflection height. This design requires much less pull-in voltage because the pull-in of one short beam will in turn reduce the height of the all subsequent beams, making it much easier to actuate. Using modeling and simulation software to characterize operations characteristics, different bimorph cantilever beam configurations are explored in order to optimize the design. These simulations show that this new "zipper" approach increases initial deflection as additional beams are added to the assembly without increasing the actuation voltage.

  8. Deflection hardening behaviour of short fibre reinforced fly ash based geopolymer composites

    International Nuclear Information System (INIS)

    Shaikh, F.U.A.

    2013-01-01

    Highlights: • Deflection hardening behaviour is achieved in the DFRGC similar to that observed in DFRCC. • The first crack load or in other word the limit of proportionality (LOP) of DFRGC is similar to that of DFRCC. • The DFRGC also exhibited higher deflection at peak load than DFRCC. • The toughness at peak load of DFRGC is also high than that of DFRCC. • The ductility of DFRGC is also higher than that of DFRCC. - Abstract: This paper reports the newly developed ductile fibre reinforced geopolymer composite (DFRGC) exhibiting deflection hardening and multiple cracking behaviour. The binder of the above composite is different from that used in conventional cement based system. The class F fly ash is used instead of Portland cement in DFRGC and is activated by alkaline liquids (sodium hydroxide and sodium silicate). In this study, two types of fibres namely steel (ST) and polyvinyl alcohol (PVA) fibres are used in mono as well as in ST–PVA hybrid form, with a total volume fraction of 2%. The deflection hardening behaviour of newly developed DFRGC is also compared with that of conventional ductile fibre reinforced cementitious composites (DFRCC). The effects of two different sizes of sand (1.18 mm, and 0.6 mm) and sand/binder ratios of 0.5 and 0.75 on the deflection hardening and multiple cracking behaviour of both DFRGC and DFRCC are also evaluated. Results revel that the deflection hardening and multiple cracking behaviour is achieved in geopolymer based DFRGC similar to that of cement based system. For a given sand size and sand content, comparable deflection hardening behaviour, ultimate flexural strength and the deflection at peak load are observed in both cement and geopolymer based composites irrespective of fibre types and combination. The deflection hardening behaviour of DFRGC is also confirmed by the calculated toughness index values of I 20 > 20. The scanning electron microscope (SEM) study shows no degradation of PVA and steel fibres in the

  9. Deflection of electron beams by ground planes

    International Nuclear Information System (INIS)

    Fernsler, R.F.; Lampe, M.

    1991-01-01

    Analytic methods are used to determine the effect of a nearby ground plane on the trajectory of a relativistic electron beam passing through dense gas. The beam is shown to respond to the ground plane in one of two distinct modes, determined by beam current and energy. Low-power beams deflect from the ground plane and tear longitudinally. High-power beams do not deflect or tear but tilt, i.e., the beam axis is no longer parallel to the direction of propagation. This conclusion is reached by computing the net beam force as a superposition of the ''bare'' ground-plane forces, the shielding forces from the beam-generated plasma, the body coupling forces induced by beam tilt, and the force that arises as the beam separates from the plasma. Effects from electromagnetic retardation and ground resistivity are shown to be negligible in typical cases of interest, and the interaction between ground planes and other external forces is discussed as well

  10. Theoretical aspects of magnetic helicity

    International Nuclear Information System (INIS)

    Hammer, J.H.

    1985-01-01

    The magnetic helicity, usually defined as K=integralA.Bdv, where A is the vector potential and B the magnetic field, measures the topological linkage of magnetic fluxes. Helicity manifests itself in the twistedness and knottedness of flux tubes. Its significance is that it is an ideal MHD invariant. While the helicity formalism has proven very useful in understanding reversed field pinch and spheromak behavior, some problems exist in applying the method consistently for complex (e.g., toroidal) conductor geometries or in situations where magnetic flux penetrates conducting walls. Recent work has attempted to generalize K to allow for all possible geometries

  11. Flow pattern-based mass and heat transfer and frictional drag of gas-non-Newtonian liquid flow in helical coil: two- and three-phase systems

    Science.gov (United States)

    Thandlam, Anil Kumar; Das, Chiranjib; Majumder, Subrata Kumar

    2017-04-01

    Investigation of wall-liquid mass transfer and heat transfer phenomena with gas-Newtonian and non-Newtonian fluids in vertically helical coil reactor have been reported in this article. Experiments were conducted to investigate the effect of various dynamic and geometric parameters on mass and heat transfer coefficients in the helical coil reactor. The flow pattern-based heat and mass transfer phenomena in the helical coil reactor are highlighted at different operating conditions. The study covered a wide range of geometric parameters such as diameter of the tube ( d t ), diameter of the coil ( D c ), diameter of the particle ( d p ), pitch difference ( p/D c ) and concentrations of non-Newtonian liquid. The correlation models for the heat and mass transfer coefficient based on the flow pattern are developed which may be useful in process scale-up of the helical coil reactor for industrial application. The frictional drag coefficient was also estimated and analyzed by mass transfer phenomena based on the electrochemical method.

  12. Deflection of resilient materials for reduction of floor impact sound.

    Science.gov (United States)

    Lee, Jung-Yoon; Kim, Jong-Mun

    2014-01-01

    Recently, many residents living in apartment buildings in Korea have been bothered by noise coming from the houses above. In order to reduce noise pollution, communities are increasingly imposing bylaws, including the limitation of floor impact sound, minimum thickness of floors, and floor soundproofing solutions. This research effort focused specifically on the deflection of resilient materials in the floor sound insulation systems of apartment houses. The experimental program involved conducting twenty-seven material tests and ten sound insulation floating concrete floor specimens. Two main parameters were considered in the experimental investigation: the seven types of resilient materials and the location of the loading point. The structural behavior of sound insulation floor floating was predicted using the Winkler method. The experimental and analytical results indicated that the cracking strength of the floating concrete floor significantly increased with increasing the tangent modulus of resilient material. The deflection of the floating concrete floor loaded at the side of the specimen was much greater than that of the floating concrete floor loaded at the center of the specimen. The Winkler model considering the effect of modulus of resilient materials was able to accurately predict the cracking strength of the floating concrete floor.

  13. Godbillon Vey Helicity and Magnetic Helicity in Magnetohydrodynamics

    Science.gov (United States)

    Webb, G. M.; Hu, Q.; Anco, S.; Zank, G. P.

    2017-12-01

    The Godbillon-Vey invariant arises in homology theory, and algebraic topology, where conditions for a layered family of 2D surfaces forms a 3D manifold were elucidated. The magnetic Godbillon-Vey helicity invariant in magnetohydrodynamics (MHD) is a helicity invariant that occurs for flows, in which the magnetic helicity density hm= A\\cdotB=0 where A is the magnetic vector potential and B is the magnetic induction. Our purpose is to elucidate the evolution of the magnetic Godbillon-Vey field η =A×B/|A|2 and the Godbillon-Vey helicity hgv}= η \\cdot∇ × η in general MHD flows in which the magnetic helicity hm≠q 0. It is shown that hm acts as a source term in the Godbillon-Vey helicity transport equation, in which hm is coupled to hgv via the shear tensor of the background flow. The transport equation for hgv depends on the electric field potential ψ , which is related to the gauge for A, which takes its simplest form for the advected A gauge in which ψ =A\\cdot u where u is the fluid velocity.

  14. Light deflection and Gauss-Bonnet theorem: definition of total deflection angle and its applications

    Science.gov (United States)

    Arakida, Hideyoshi

    2018-05-01

    In this paper, we re-examine the light deflection in the Schwarzschild and the Schwarzschild-de Sitter spacetime. First, supposing a static and spherically symmetric spacetime, we propose the definition of the total deflection angle α of the light ray by constructing a quadrilateral Σ^4 on the optical reference geometry M^opt determined by the optical metric \\bar{g}_{ij}. On the basis of the definition of the total deflection angle α and the Gauss-Bonnet theorem, we derive two formulas to calculate the total deflection angle α ; (1) the angular formula that uses four angles determined on the optical reference geometry M^opt or the curved (r, φ ) subspace M^sub being a slice of constant time t and (2) the integral formula on the optical reference geometry M^opt which is the areal integral of the Gaussian curvature K in the area of a quadrilateral Σ ^4 and the line integral of the geodesic curvature κ _g along the curve C_{Γ}. As the curve C_{Γ}, we introduce the unperturbed reference line that is the null geodesic Γ on the background spacetime such as the Minkowski or the de Sitter spacetime, and is obtained by projecting Γ vertically onto the curved (r, φ ) subspace M^sub. We demonstrate that the two formulas give the same total deflection angle α for the Schwarzschild and the Schwarzschild-de Sitter spacetime. In particular, in the Schwarzschild case, the result coincides with Epstein-Shapiro's formula when the source S and the receiver R of the light ray are located at infinity. In addition, in the Schwarzschild-de Sitter case, there appear order O(Lambda;m) terms in addition to the Schwarzschild-like part, while order O(Λ) terms disappear.

  15. Design windows and cost analysis on helical reactors

    International Nuclear Information System (INIS)

    Kozaki, Y.; Imagawa, S.; Sagara, A.

    2007-01-01

    The LHD type helical reactors are characterized by a large major radius but slender helical coil, which give us different approaches for power plants from tokamak reactors. For searching design windows of helical reactors and discussing their potential as power plants, we have developed a mass-cost estimating model linked with system design code (HeliCos), thorough studying the relationships between major plasma parameters and reactor parameters, and weight of major components. In regard to cost data we have much experience through preparing ITER construction. To compare the weight and cost of magnet systems between tokamak and helical reactors, we broke down magnet systems and cost factors, such as weights of super conducting strands, conduits, support structures, and winding unit costs, through estimating ITER cost data basis. Based on FFHR2m1 deign we considered a typical 3 GWth helical plant (LHD type) with the same magnet size, coil major radius Rc 14 m, magnetic energy 120 GJ, but increasing plasma densities. We evaluated the weight and cost of magnet systems of 3 GWth helical plant, the total magnet weights of 16,000ton and costs of 210 BYen, which are similar values of tokamak reactors (10,200 ton, 110 BYen in ITER 2002 report, and 21,900 ton, 275 BYen in ITER FDR1999). The costs of strands and winding occupy 70% of total magnet costs, and influence entire power plants economics. The design windows analysis and comparative economics studies to optimize the main reactor parameters have been carried out. Economics studies show that it is misunderstanding to consider helical coils are too large and too expensive to achieve power plants. But we should notice that the helical reactor design windows and economics are very sensitive to allowable blanket space (depend on ergodic layer conditions) and diverter configuration for decreasing heat loads. (orig.)

  16. Helicity multiplexed broadband metasurface holograms.

    Science.gov (United States)

    Wen, Dandan; Yue, Fuyong; Li, Guixin; Zheng, Guoxing; Chan, Kinlong; Chen, Shumei; Chen, Ming; Li, King Fai; Wong, Polis Wing Han; Cheah, Kok Wai; Pun, Edwin Yue Bun; Zhang, Shuang; Chen, Xianzhong

    2015-09-10

    Metasurfaces are engineered interfaces that contain a thin layer of plasmonic or dielectric nanostructures capable of manipulating light in a desirable manner. Advances in metasurfaces have led to various practical applications ranging from lensing to holography. Metasurface holograms that can be switched by the polarization state of incident light have been demonstrated for achieving polarization multiplexed functionalities. However, practical application of these devices has been limited by their capability for achieving high efficiency and high image quality. Here we experimentally demonstrate a helicity multiplexed metasurface hologram with high efficiency and good image fidelity over a broad range of frequencies. The metasurface hologram features the combination of two sets of hologram patterns operating with opposite incident helicities. Two symmetrically distributed off-axis images are interchangeable by controlling the helicity of the input light. The demonstrated helicity multiplexed metasurface hologram with its high performance opens avenues for future applications with functionality switchable optical devices.

  17. The Deflector Selector: A machine learning framework for prioritizing hazardous object deflection technology development

    Science.gov (United States)

    Nesvold, E. R.; Greenberg, A.; Erasmus, N.; van Heerden, E.; Galache, J. L.; Dahlstrom, E.; Marchis, F.

    2018-05-01

    Several technologies have been proposed for deflecting a hazardous Solar System object on a trajectory that would otherwise impact the Earth. The effectiveness of each technology depends on several characteristics of the given object, including its orbit and size. The distribution of these parameters in the likely population of Earth-impacting objects can thus determine which of the technologies are most likely to be useful in preventing a collision with the Earth. None of the proposed deflection technologies has been developed and fully tested in space. Developing every proposed technology is currently prohibitively expensive, so determining now which technologies are most likely to be effective would allow us to prioritize a subset of proposed deflection technologies for funding and development. We present a new model, the Deflector Selector, that takes as its input the characteristics of a hazardous object or population of such objects and predicts which technology would be able to perform a successful deflection. The model consists of a machine-learning algorithm trained on data produced by N-body integrations simulating the deflections. We describe the model and present the results of tests of the effectiveness of nuclear explosives, kinetic impactors, and gravity tractors on three simulated populations of hazardous objects.

  18. The Deflector Selector: A Machine Learning Framework for Prioritizing Hazardous Object Deflection Technology Development

    Science.gov (United States)

    Nesvold, Erika; Greenberg, Adam; Erasmus, Nicolas; Van Heerden, Elmarie; Galache, J. L.; Dahlstrom, Eric; Marchis, Franck

    2018-01-01

    Several technologies have been proposed for deflecting a hazardous Solar System object on a trajectory that would otherwise impact the Earth. The effectiveness of each technology depends on several characteristics of the given object, including its orbit and size. The distribution of these parameters in the likely population of Earth-impacting objects can thus determine which of the technologies are most likely to be useful in preventing a collision with the Earth. None of the proposed deflection technologies has been developed and fully tested in space. Developing every proposed technology is currently prohibitively expensive, so determining now which technologies are most likely to be effective would allow us to prioritize a subset of proposed deflection technologies for funding and development. We will present a new model, the Deflector Selector, that takes as its input the characteristics of a hazardous object or population of such objects and predicts which technology would be able to perform a successful deflection. The model consists of a machine-learning algorithm trained on data produced by N-body integrations simulating the deflections. We will describe the model and present the results of tests of the effectiveness of nuclear explosives, kinetic impactors, and gravity tractors on three simulated populations of hazardous objects.

  19. Employing helicity amplitudes for resummation

    International Nuclear Information System (INIS)

    Moult, Ian; Stewart, Iain W.; Tackmann, Frank J.; Waalewijn, Wouter J.; Amsterdam Univ.

    2015-08-01

    Many state-of-the-art QCD calculations for multileg processes use helicity amplitudes as their fundamental ingredients. We construct a simple and easy-to-use helicity operator basis in soft-collinear effective theory (SCET), for which the hard Wilson coefficients from matching QCD onto SCET are directly given in terms of color-ordered helicity amplitudes. Using this basis allows one to seamlessly combine fixed-order helicity amplitudes at any order they are known with a resummation of higher-order logarithmic corrections. In particular, the virtual loop amplitudes can be employed in factorization theorems to make predictions for exclusive jet cross sections without the use of numerical subtraction schemes to handle real-virtual infrared cancellations. We also discuss matching onto SCET in renormalization schemes with helicities in 4- and d-dimensions. To demonstrate that our helicity operator basis is easy to use, we provide an explicit construction of the operator basis, as well as results for the hard matching coefficients, for pp → H+0,1,2 jets, pp → W/Z/γ+0,1,2 jets, and pp → 2,3 jets. These operator bases are completely crossing symmetric, so the results can easily be applied to processes with e + e - and e - p collisions.

  20. Conversion of helical tomotherapy plans to step-and-shoot IMRT plans--Pareto front evaluation of plans from a new treatment planning system.

    Science.gov (United States)

    Petersson, Kristoffer; Ceberg, Crister; Engström, Per; Benedek, Hunor; Nilsson, Per; Knöös, Tommy

    2011-06-01

    The resulting plans from a new type of treatment planning system called SharePlan have been studied. This software allows for the conversion of treatment plans generated in a TomoTherapy system for helical delivery, into plans deliverable on C-arm linear accelerators (linacs), which is of particular interest for clinics with a single TomoTherapy unit. The purpose of this work was to evaluate and compare the plans generated in the SharePlan system with the original TomoTherapy plans and with plans produced in our clinical treatment planning system for intensity-modulated radiation therapy (IMRT) on C-arm linacs. In addition, we have analyzed how the agreement between SharePlan and TomoTherapy plans depends on the number of beams and the total number of segments used in the optimization. Optimized plans were generated for three prostate and three head-and-neck (H&N) cases in the TomoTherapy system, and in our clinical treatment planning systems (TPS) used for IMRT planning with step-and-shoot delivery. The TomoTherapy plans were converted into step-and-shoot IMRT plans in SharePlan. For each case, a large number of Pareto optimal plans were created to compare plans generated in SharePlan with plans generated in the Tomotherapy system and in the clinical TPS. In addition, plans were generated in SharePlan for the three head-and-neck cases to evaluate how the plan quality varied with the number of beams used. Plans were also generated with different number of beams and segments for other patient cases. This allowed for an evaluation of how to minimize the number of required segments in the converted IMRT plans without compromising the agreement between them and the original TomoTherapy plans. The plans made in SharePlan were as good as or better than plans from our clinical system, but they were not as good as the original TomoTherapy plans. This was true for both the head-and-neck and the prostate cases, although the differences between the plans for the latter were

  1. Coherent Bichromatic Force Deflection of Molecules

    Science.gov (United States)

    Kozyryev, Ivan; Baum, Louis; Aldridge, Leland; Yu, Phelan; Eyler, Edward E.; Doyle, John M.

    2018-02-01

    We demonstrate the effect of the coherent optical bichromatic force on a molecule, the polar free radical strontium monohydroxide (SrOH). A dual-frequency retroreflected laser beam addressing the X˜2Σ+↔A˜2Π1 /2 electronic transition coherently imparts momentum onto a cryogenic beam of SrOH. This directional photon exchange creates a bichromatic force that transversely deflects the molecules. By adjusting the relative phase between the forward and counterpropagating laser beams we reverse the direction of the applied force. A momentum transfer of 70 ℏk is achieved with minimal loss of molecules to dark states. Modeling of the bichromatic force is performed via direct numerical solution of the time-dependent density matrix and is compared with experimental observations. Our results open the door to further coherent manipulation of molecular motion, including the efficient optical deceleration of diatomic and polyatomic molecules with complex level structures.

  2. Helicity evolution at small x

    International Nuclear Information System (INIS)

    Kovchegov, Yuri V.; Pitonyak, Daniel; Sievert, Matthew D.

    2016-01-01

    We construct small-x evolution equations which can be used to calculate quark and anti-quark helicity TMDs and PDFs, along with the g 1 structure function. These evolution equations resum powers of α s ln 2  (1/x) in the polarization-dependent evolution along with the powers of α s ln (1/x) in the unpolarized evolution which includes saturation effects. The equations are written in an operator form in terms of polarization-dependent Wilson line-like operators. While the equations do not close in general, they become closed and self-contained systems of non-linear equations in the large-N c and large-N c   N f limits. As a cross-check, in the ladder approximation, our equations map onto the same ladder limit of the infrared evolution equations for the g 1 structure function derived previously by Bartels, Ermolaev and Ryskin http://dx.doi.org/10.1007/s002880050285.

  3. Study on the causes and methods of influencing concrete deflection

    Science.gov (United States)

    Zhou, Ying; Zhou, Xiang; Tang, Jinyu

    2017-09-01

    Under the long-term effect of static load on reinforced concrete beam, the stiffness decreases and the deformation increases with time. Therefore, the calculation of deflection is more complicated. According to the domestic and foreign research results by experiment the flexural deflection of reinforced concrete, creep, age, the thickness of the protective layer, the relative slip, the combination of steel yielding factors of reinforced concrete deflection are summarized, analyzed the advantages and disadvantages of the traditional direct measurement of deflection, that by increasing the beam height, increasing the moment of inertia, ncrease prestressed reinforcement ratio, arching, reduce the load, and other measures to reduce the deflection of prestressed construction, improve the reliability of structure.

  4. Pulling Helices inside Bacteria: Imperfect Helices and Rings

    Science.gov (United States)

    Allard, Jun F.; Rutenberg, Andrew D.

    2009-04-01

    We study steady-state configurations of intrinsically-straight elastic filaments constrained within rod-shaped bacteria that have applied forces distributed along their length. Perfect steady-state helices result from axial or azimuthal forces applied at filament ends, however azimuthal forces are required for the small pitches observed for MreB filaments within bacteria. Helix-like configurations can result from distributed forces, including coexistence between rings and imperfect helices. Levels of expression and/or bundling of the polymeric protein could mediate this coexistence.

  5. Load Deflection Characteristics of Nickel Titanium Initial Archwires

    Directory of Open Access Journals (Sweden)

    Hossein Aghili

    2016-05-01

    Full Text Available Objectives: The aim of this study was to assess and compare the characteristics of commonly used initial archwires by their load deflection graphs.Materials and Methods: This study tested three wire designs namely copper nickel titanium (CNT, nickel titanium (NiTi, and multi-strand NiTi (MSNT archwires engaged in passive self-ligating (PSL brackets, active self-ligating (ASL brackets or conventional brackets. To evaluate the mechanical characteristics of the specimens, a three-point bending test was performed. The testing machine vertically applied force on the midpoint of the wire between the central incisor and canine teeth to obtain 2 and 4mm of deflection. The force level at maximum deflection and characteristics of plateau (the average plateau load and the plateau length were recorded. Two-way ANOVA and Tukey’s test were used at P <0.05 level of significance.Results: Force level at maximum deflection and plateau length were significantly affected by the amount of deflection. The type of archwires and brackets had significant effects on force level at maximum deflection, and plateau length. However, the bracket type had no significant effect on the average plateau force.Conclusion: With any type of brackets in deflections of 2 and 4mm, MSNT wire exerted the lowest while NiTi wire exerted the highest force level at maximum deflection and plateau phase. The force level at maximum deflection and the plateau length increased with raising the amount of primary deflection; however the average plateau force did not change significantly.

  6. Nonlinear Coupled Dynamics of a Rod Fastening Rotor under Rub-Impact and Initial Permanent Deflection

    Directory of Open Access Journals (Sweden)

    Liang Hu

    2016-10-01

    Full Text Available A nonlinear coupled dynamic model of a rod fastening rotor under rub-impact and initial permanent deflection was developed in this paper. The governing motion equation was derived by the D’Alembert principle considering the contact characteristic between disks, nonlinear oil-film force, rub-impact force, unbalance mass, etc. The contact effects between disks was modeled as a flexural spring with cubical nonlinear stiffness. The coupled nonlinear dynamic phenomena of the rub-impact rod fastening rotor bearing system with initial permanent deflection were investigated by the fourth-order Runge-Kutta method. Bifurcation diagram, vibration waveform, frequency spectrum, shaft orbit and Poincaré map are used to illustrate the rich diversity of the system response with complicated dynamics. The studies indicate that the coupled dynamic responses of the rod fastening rotor bearing system under rub-impact and initial permanent deflection exhibit a rich nonlinear dynamic diversity, synchronous periodic-1 motion, multiple periodic motion, quasi-periodic motion and chaotic motion can be observed under certain conditions. Larger radial stiffness of the stator will simplify the system motion and make the oil whirl weaker or even disappear at a certain rotating speed. With the increase of initial permanent deflection length, the instability speed of the system gradually rises, and the chaotic motion region gets smaller and smaller. The corresponding results can provide guidance for the fault diagnosis of a rub-impact rod fastening rotor with initial permanent deflection and contribute to the further understanding of the nonlinear dynamic characteristics of the rod fastening rotor bearing system.

  7. Planetary Defense From Space: Part 2 (Simple) Asteroid Deflection Law

    Science.gov (United States)

    Maccone, Claudio

    2006-06-01

    A system of two space bases housing missiles for an efficient Planetary Defense of the Earth from asteroids and comets was firstly proposed by this author in 2002. It was then shown that the five Lagrangian points of the Earth Moon system lead naturally to only two unmistakable locations of these two space bases within the sphere of influence of the Earth. These locations are the two Lagrangian points L1 (in between the Earth and the Moon) and L3 (in the direction opposite to the Moon from the Earth). In fact, placing missiles based at L1 and L3 would enable the missiles to deflect the trajectory of incoming asteroids by hitting them orthogonally to their impact trajectory toward the Earth, thus maximizing the deflection at best. It was also shown that confocal conics are the only class of missile trajectories fulfilling this “best orthogonal deflection” requirement. The mathematical theory developed by the author in the years 2002 2004 was just the beginning of a more expanded research program about the Planetary Defense. In fact, while those papers developed the formal Keplerian theory of the Optimal Planetary Defense achievable from the Earth Moon Lagrangian points L1 and L3, this paper is devoted to the proof of a simple “(small) asteroid deflection law” relating directly the following variables to each other:the speed of the arriving asteroid with respect to the Earth (known from the astrometric observations);the asteroid's size and density (also supposed to be known from astronomical observations of various types);the “security radius” of the Earth, that is, the minimal sphere around the Earth outside which we must force the asteroid to fly if we want to be safe on Earth. Typically, we assume the security radius to equal about 10,000 km from the Earth center, but this number might be changed by more refined analyses, especially in the case of “rubble pile” asteroids;the distance from the Earth of the two Lagrangian points L1 and L3 where the

  8. Generalized helicity and Beltrami fields

    Energy Technology Data Exchange (ETDEWEB)

    Buniy, Roman V., E-mail: roman.buniy@gmail.com [Schmid College of Science, Chapman University, Orange, CA 92866 (United States); Isaac Newton Institute, University of Cambridge, Cambridge, CB3 0EH (United Kingdom); Kephart, Thomas W., E-mail: tom.kephart@gmail.com [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Isaac Newton Institute, University of Cambridge, Cambridge, CB3 0EH (United Kingdom)

    2014-05-15

    We propose covariant and non-abelian generalizations of the magnetic helicity and Beltrami equation. The gauge invariance, variational principle, conserved current, energy–momentum tensor and choice of boundary conditions elucidate the subject. In particular, we prove that any extremal of the Yang–Mills action functional 1/4 ∫{sub Ω}trF{sub μν}F{sup μν}d{sup 4}x subject to the local constraint ε{sup μναβ}trF{sub μν}F{sub αβ}=0 satisfies the covariant non-abelian Beltrami equation. -- Highlights: •We introduce the covariant non-abelian helicity and Beltrami equation. •The Yang–Mills action and instanton term constraint lead to the Beltrami equation. •Solutions of the Beltrami equation conserve helicity.

  9. Generalized helicity and Beltrami fields

    International Nuclear Information System (INIS)

    Buniy, Roman V.; Kephart, Thomas W.

    2014-01-01

    We propose covariant and non-abelian generalizations of the magnetic helicity and Beltrami equation. The gauge invariance, variational principle, conserved current, energy–momentum tensor and choice of boundary conditions elucidate the subject. In particular, we prove that any extremal of the Yang–Mills action functional 1/4 ∫ Ω trF μν F μν d 4 x subject to the local constraint ε μναβ trF μν F αβ =0 satisfies the covariant non-abelian Beltrami equation. -- Highlights: •We introduce the covariant non-abelian helicity and Beltrami equation. •The Yang–Mills action and instanton term constraint lead to the Beltrami equation. •Solutions of the Beltrami equation conserve helicity

  10. Toroidal helical quartz forming machine

    International Nuclear Information System (INIS)

    Hanks, K.W.; Cole, T.R.

    1977-01-01

    The Scyllac fusion experimental machine used 10 cm diameter smooth bore discharge tubes formed into a simple toroidal shape prior to 1974. At about that time, it was discovered that a discharge tube was required to follow the convoluted shape of the load coil. A machine was designed and built to form a fused quartz tube with a toroidal shape. The machine will accommodate quartz tubes from 5 cm to 20 cm diameter forming it into a 4 m toroidal radius with a 1 to 5 cm helical displacement. The machine will also generate a helical shape on a linear tube. Two sets of tubes with different helical radii and wavelengths have been successfully fabricated. The problems encountered with the design and fabrication of this machine are discussed

  11. The Significance of the Influence of the CME Deflection in Interplanetary Space on the CME Arrival at Earth

    Science.gov (United States)

    Zhuang, Bin; Wang, Yuming; Shen, Chenglong; Liu, Siqing; Wang, Jingjing; Pan, Zonghao; Li, Huimin; Liu, Rui

    2017-08-01

    As one of the most violent astrophysical phenomena, coronal mass ejections (CMEs) have strong potential space weather effects. However, not all Earth-directed CMEs encounter the Earth and produce geo-effects. One reason is the deflected propagation of CMEs in interplanetary space. Although there have been several case studies clearly showing such deflections, it has not yet been statistically assessed how significantly the deflected propagation would influence the CME’s arrival at Earth. We develop an integrated CME-arrival forecasting (iCAF) system, assembling the modules of CME detection, three-dimensional (3D) parameter derivation, and trajectory reconstruction to predict whether or not a CME arrives at Earth, and we assess the deflection influence on the CME-arrival forecasting. The performance of iCAF is tested by comparing the two-dimensional (2D) parameters with those in the Coordinated Data Analysis Workshop (CDAW) Data Center catalog, comparing the 3D parameters with those of the gradual cylindrical shell model, and estimating the success rate of the CME Earth-arrival predictions. It is found that the 2D parameters provided by iCAF and the CDAW catalog are consistent with each other, and the 3D parameters derived by the ice cream cone model based on single-view observations are acceptable. The success rate of the CME-arrival predictions by iCAF with deflection considered is about 82%, which is 19% higher than that without deflection, indicating the importance of the CME deflection for providing a reliable forecasting. Furthermore, iCAF is a worthwhile project since it is a completely automatic system with deflection taken into account.

  12. A numerical study of the stabilitiy of helical vortices using vortex methods

    Energy Technology Data Exchange (ETDEWEB)

    Walther, J H [Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Lyngby (Denmark); Guenot, M [Enginering College in Industrial Systems, FR-17041, La Rochelle (France); Machefaux, E [Enginering College in Industrial Systems, FR-17041, La Rochelle (France); Rasmussen, J T [Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Lyngby (Denmark); Chatelain, P [Computational Laboratory, ETH Zurich, CH-8092 Zurich (Switzerland); Okulov, V L [Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Lyngby (Denmark); Soerensen, J N [Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Lyngby (Denmark); Bergdorf, M [Computational Laboratory, ETH Zurich, CH-8092 Zurich (Switzerland); Koumoutsakos, P [Computational Laboratory, ETH Zurich, CH-8092 Zurich (Switzerland)

    2007-07-15

    We present large-scale parallel direct numerical simulations using particle vortex methods of the instability of the helical vortices. We study the instability of a single helical vortex and find good agreement with inviscid theory. We outline equilibrium configurations for three double helical vortices-similar to those produced by three blade wind turbines. The simulations confirm the stability of the inviscid model, but predict a breakdown of the vortical system due to viscosity.

  13. A numerical study of the stabilitiy of helical vortices using vortex methods

    International Nuclear Information System (INIS)

    Walther, J H; Guenot, M; Machefaux, E; Rasmussen, J T; Chatelain, P; Okulov, V L; Soerensen, J N; Bergdorf, M; Koumoutsakos, P

    2007-01-01

    We present large-scale parallel direct numerical simulations using particle vortex methods of the instability of the helical vortices. We study the instability of a single helical vortex and find good agreement with inviscid theory. We outline equilibrium configurations for three double helical vortices-similar to those produced by three blade wind turbines. The simulations confirm the stability of the inviscid model, but predict a breakdown of the vortical system due to viscosity

  14. A semi-analytical study on helical springs made of shape memory polymer

    International Nuclear Information System (INIS)

    Baghani, M; Naghdabadi, R; Arghavani, J

    2012-01-01

    In this paper, the responses of shape memory polymer (SMP) helical springs under axial force are studied both analytically and numerically. In the analytical solution, we first derive the response of a cylindrical tube under torsional loadings. This solution can be used for helical springs in which both the curvature and pitch effects are negligible. This is the case for helical springs with large ratios of the mean coil radius to the cross sectional radius (spring index) and also small pitch angles. Making use of this solution simplifies the analysis of the helical springs to that of the torsion of a straight bar with circular cross section. The 3D phenomenological constitutive model recently proposed for SMPs is also reduced to the 1D shear case. Thus, an analytical solution for the torsional response of SMP tubes in a full cycle of stress-free strain recovery is derived. In addition, the curvature effect is added to the formulation and the SMP helical spring is analyzed using the exact solution presented for torsion of curved SMP tubes. In this modified solution, the effect of the direct shear force is also considered. In the numerical analysis, the 3D constitutive equations are implemented in a finite element program and a full cycle of stress-free strain recovery of an SMP (extension or compression) helical spring is simulated. Analytical and numerical results are compared and it is shown that the analytical solution gives accurate stress distributions in the cross section of the helical SMP spring besides the global load–deflection response. Some case studies are presented to show the validity of the presented analytical method. (paper)

  15. Helicity and evanescent waves. [Energy transport velocity, helicity, Lorentz transformation

    Energy Technology Data Exchange (ETDEWEB)

    Agudin, J L; Platzeck, A M [La Plata Univ. Nacional (Argentina); Albano, J R [Instituto de Astronomia y Fisica del Espacio, Buenos Aires, Argentina

    1978-02-20

    It is shown that the projection of the angular momentum of a circularly polarized electromagnetic evanescent wave along the mean velocity of energy transport (=helicity) can be reverted by a Lorentz transformation, in spite of the fact that this velocity is c.

  16. l=1 helical axis heliotron device in Kyoto university

    International Nuclear Information System (INIS)

    Nagasaki, K.; Sano, F.; Mizuuchi, T.; Hanatani, K.; Okada, H.; Obiki, T.

    1999-01-01

    Helical systems are an attractive candidate for magnetic fusion reactor. Recently, there has been great progress in theoretical research of three dimensional magnetic field structures, resulting in several kinds of confinement optimization being proposed for toroidal magnetic confinement system. For example, some sophisticated ideas have appeared on stage such as quasi-helical symmetry and quasi-isodynamic system. To find experimentally which way is the best Optimisation, a new helical axis heliotron device, so called 'Heliotron J', is under construction in the Institute of Advanced Energy, Kyoto University, Japan. In this conference, the basic concept and the present status will be presented. In the conventional plane axis helical system, it was difficult to have both good particle confinement and good MHD stability simultaneously. The goal of Heliotron J project is to clarify their compatibility in the spatial axis toroidal device. The best way for Optimising the helical magnetic field configuration will be explored by investigating the plasma response to the change in the field components. The main subjects for plasma experiment are: demonstration of the existence of good magnetic flux surfaces, reduction of neoclassical transport in collisionless regime, MHD Stabilisation in high β plasma, controllability of bootstrap current, good confinement of high energy particles

  17. Coupler induced monopole component and its minimization in deflecting cavities

    Directory of Open Access Journals (Sweden)

    P. K. Ambattu

    2013-06-01

    Full Text Available Deflecting cavities are used in particle accelerators for the manipulation of charged particles by deflecting or crabbing (rotating them. For short deflectors, the effect of the power coupler on the deflecting field can become significant. The particular power coupler type can introduce multipole rf field components and coupler-specific wakefields. Coupler types that would normally be considered like standard on-cell coupler, waveguide coupler, or mode-launcher coupler could have one or two rf feeds. The major advantage of a dual-feed coupler is the absence of monopole and quadrupole rf field components in the deflecting structure. However, a dual-feed coupler is mechanically more complex than a typical single-feed coupler and needs a splitter. For most applications, deflecting structures are placed in regions where there is small space hence reducing the size of the structure is very desirable. This paper investigates the multipole field components of the deflecting mode in single-feed couplers and ways to overcome the effect of the monopole component on the beam. Significant advances in performance have been demonstrated. Additionally, a novel coupler design is introduced which has no monopole field component to the deflecting mode and is more compact than the conventional dual-feed coupler.

  18. Versatile H+ beam chopper system at LAMPF

    International Nuclear Information System (INIS)

    Lunsford, J.S.; Lawrence, G.P.; Bentley, R.F.

    1979-01-01

    The H + chopper system at LAMPF provides two modes (A and B) of beam chopping. Mode A provides single micropulses separated by 1 μs or more. Mode B provides a single pulse 50-ns to 10-μs long at the LAMPF repetition rate of 12 Hz. The mode of operation is selected with coaxial relays which can switch during the dead time between LAMPF macropulses. The chopper consists of 1-m-long push-pull helical-wound slow-wave deflecting structures having an axial pulse velocity of 0.04c, which matches the velocity of the proton beam. The helix ground-planes are biased by a pulser providing push-pull 500-V pulses to deflect the H + beam from the injection channel. In chopping mode A, the helical windings are driven by push-pull, 1000-V, 5-ns pulses delivered by a circuit utilizing avalanche transistors and planar triodes. In mode B, the helical windings are driven by push-pull, 1000-V, 50-ns to 10-μs long pulses, produced by a circuit utilizing beam-power tetrodes and fast SCRs. In both modes, these pulses cancel the ground-plane bias and permit beam pulses to be delivered to the linac

  19. Helical coil alignment in the advanced toroidal facility

    International Nuclear Information System (INIS)

    Taylor, D.J.; Cole, M.J.; Johnson, R.L.; Nelson, B.E.; Warwick, J.E.; Whitson, J.C.

    1985-01-01

    This paper presents a brief overview of the helical coil design concept, detailed descriptions of the method for installation and alignment, and discussions of segment installation and alignment equipment. Alignment is accomplished by optical methods using electronic theodolites connected to a microcomputer to form a coordinate measurement system. The coordinate measurement system is described in detail, along with target selection and fixturing for manipulation of the helical coil segments during installation. In addition, software is described including vendor-supplied software used in the coordinate measurement system and in-house-developed software used to calibrate segment and positioning fixture motion. 2 refs., 8 figs

  20. Progressive and resonant wave helices application to electron paramagnetic resonance; Helices a ondes progressives et resonnantes application a la resonance paramagnetique electronique

    Energy Technology Data Exchange (ETDEWEB)

    Volino, F [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    We show that helices can be used as resonant systems. Their properties are theoretically and experimentally studied. We describe resonant helices for electron paramagnetic resonance in X-band and develop a comparison between their sensitivity and the sensitivity of a normal resonant cavity. For cylindrical samples less than 3 mm diameter, the helix is more sensitive and can produce more intense microwave magnetic fields. (author) [French] Il est montre que les helices peuvent etre utilisees comme systeme resonnant. Leurs proprietes sont discutees theoriquement et experimentalement. Des helices resonnantes en bande X pour la resonance paramagnetique electronique sont decrites et leur sensibilite est comparee a celle des cavites resonnantes. Pour des echantillons cylindriques de moins de 3 mm de diametre, l'helice est plus sensible et peut produire des champs magnetiques hyper fins plus intenses. (auteur)

  1. Progressive and resonant wave helices application to electron paramagnetic resonance; Helices a ondes progressives et resonnantes application a la resonance paramagnetique electronique

    Energy Technology Data Exchange (ETDEWEB)

    Volino, F. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    We show that helices can be used as resonant systems. Their properties are theoretically and experimentally studied. We describe resonant helices for electron paramagnetic resonance in X-band and develop a comparison between their sensitivity and the sensitivity of a normal resonant cavity. For cylindrical samples less than 3 mm diameter, the helix is more sensitive and can produce more intense microwave magnetic fields. (author) [French] Il est montre que les helices peuvent etre utilisees comme systeme resonnant. Leurs proprietes sont discutees theoriquement et experimentalement. Des helices resonnantes en bande X pour la resonance paramagnetique electronique sont decrites et leur sensibilite est comparee a celle des cavites resonnantes. Pour des echantillons cylindriques de moins de 3 mm de diametre, l'helice est plus sensible et peut produire des champs magnetiques hyper fins plus intenses. (auteur)

  2. Parameterization and measurements of helical magnetic fields

    International Nuclear Information System (INIS)

    Fischer, W.; Okamura, M.

    1997-01-01

    Magnetic fields with helical symmetry can be parameterized using multipole coefficients (a n , b n ). We present a parameterization that gives the familiar multipole coefficients (a n , b n ) for straight magnets when the helical wavelength tends to infinity. To measure helical fields all methods used for straight magnets can be employed. We show how to convert the results of those measurements to obtain the desired helical multipole coefficients (a n , b n )

  3. Applications of 2D helical vortex dynamics

    DEFF Research Database (Denmark)

    Okulov, Valery; Sørensen, Jens Nørkær

    2010-01-01

    In the paper, we show how the assumption of helical symmetry in the context of 2D helical vortices can be exploited to analyse and to model various cases of rotating flows. From theory, examples of three basic applications of 2D dynamics of helical vortices embedded in flows with helical symmetry...... of the vorticity field are addressed. These included some of the problems related to vortex breakdown, instability of far wakes behind rotors and vortex theory of ideal rotors....

  4. Double Helical Gear Performance Results in High Speed Gear Trains

    Science.gov (United States)

    Handschuh, Robert F.; Ehinger, Ryan; Sinusas, Eric; Kilmain, Charles

    2010-01-01

    The operation of high speed gearing systems in the transmissions of tiltrotor aircraft has an effect on overall propulsion system efficiency. Recent work has focused on many aspects of high-speed helical gear trains as would be used in tiltrotor aircraft such as operational characteristics, comparison of analytical predictions to experimental data and the affect of superfinishing on transmission performance. Baseline tests of an aerospace quality system have been conducted in the NASA Glenn High-Speed Helical Gear Train Test Facility and have been described in earlier studies. These earlier tests had utilized single helical gears. The results that will be described in this study are those attained using double helical gears. This type of gear mesh can be configured in this facility to either pump the air-oil environment from the center gap between the meshing gears to the outside of tooth ends or in the reverse direction. Tests were conducted with both inward and outward air-oil pumping directions. Results are compared to the earlier baseline results of single helical gears.

  5. Biaxial and antiferroelectric structure of the orthogonal smectic phase of a bent-shaped molecule and helical structure in a chiral mixture system

    Science.gov (United States)

    Kang, Sungmin; Nguyen, Ha; Nakajima, Shunpei; Tokita, Masatoshi; Watanabe, Junji

    2013-05-01

    We examined the biaxial and antiferroelectric properties in the Smectic-APA (Sm-APA) phase of bent-shaped DC-S-8. The biaxiality, which results from the existence of a secondary director, was well established from birefringence observations in the homeotropically aligned Sm-APA. By entering into Sm-APA phase, the birefringence (Δn, difference between two refractive indices of short axes) continuously increased from 0 to 0.02 with decreasing temperature. The antiferroelectric switching and second harmonic generation (SHG) activity on the field-on state were also observed in the Sm-APA phase, and the evaluated spontaneous polarization (PS) value strongly depended on temperature. The temperature dependence of Δn and PS resembles each other and follows Haller's approximation, showing that the biaxiality is due to polar packing in which the molecules are preferentially packed with their bent direction arranged in the same direction, and that the phase transition of Sm-APA to Sm-A is second order. The biaxiality was further examined in chiral Sm-APA*. Doping with chiral components induced the helical twisting of the secondary director in the Sm-APA* phase, which was confirmed by observing the reflection of the circular dichroism (CD) bands in the homeotropically aligned cell. The helical pitch of Sm-APA* is tunable in the range of 300-700 nm wavelength with a variation in the chiral content of 5 to 10 weight (wt)%.

  6. ICRF heating on helical devices

    International Nuclear Information System (INIS)

    Rasmussen, D.A.; Lyon, J.F.; Hoffman, D.J.; Murakami, M.; England, A.C.; Wilgen, J.B.; Jaeger, E.F.; Wang, C.; Batchelor, D.B.

    1995-01-01

    Ion cyclotron range of frequency (ICRF) heating is currently in use on CHS and W7-AS and is a major element of the heating planned for steady state helical devices. In helical devices, the lack of a toroidal current eliminates both disruptions and the need for ICRF current drive, simplifying the design of antenna structures as compared to tokamak applications. However the survivability of plasma facing components and steady state cooling issues are directly applicable to tokamak devices. Results from LHD steady state experiments should be available on a time scale to strongly influence the next generation of steady state tokamak experiments. The helical plasma geometry provides challenges not faced with tokamak ICRF heating, including the potential for enhanced fast ion losses, impurity accumulation, limited access for antenna structures, and open magnetic field lines in the plasma edge. The present results and near term plans provide the basis for steady state ICRF heating of larger helical devices. An approach which includes direct electron, mode conversion, ion minority and ion Bernstein wave heating addresses these issues

  7. ICRF heating on helical devices

    International Nuclear Information System (INIS)

    Rasmussen, D.A.; Lyon, J.F.; Hoffman, D.J.

    1995-01-01

    Ion cyclotron range of frequency (ICRF) heating is currently in use on CHS and W7AS and is a major element of the heating planned for steady state helical devices. In helical devices, the lack of a toroidal current eliminates both disruptions and the need for ICRF current drive, simplifying the design of antenna structures as compared to tokamak applications. However the survivability of plasma facing components and steady state cooling issues are directly applicable to tokamak devices. Results from LHD steady state experiments should be available on a time scale to strongly influence the next generation of steady state tokamak experiments. The helical plasma geometry provides challenges not faced with tokamak ICRF heating, including the potential for enhanced fast ion losses, impurity accumulation, limited access for antenna structures, and open magnetic field lines in the plasma edge. The present results and near term plans provide the basis for steady state ICRF heating of larger helical devices. An approach which includes direct electron, mode conversion, ion minority and ion Bernstein wave heating addresses these issues

  8. The helical tomotherapy thread effect

    International Nuclear Information System (INIS)

    Kissick, M.W.; Fenwick, J.; James, J.A.; Jeraj, R.; Kapatoes, J.M.; Keller, H.; Mackie, T.R.; Olivera, G.; Soisson, E.T.

    2005-01-01

    Inherent to helical tomotherapy is a dose variation pattern that manifests as a 'ripple' (peak-to-trough relative to the average). This ripple is the result of helical beam junctioning, completely unique to helical tomotherapy. Pitch is defined as in helical CT, the couch travel distance for a complete gantry rotation relative to the axial beam width at the axis of rotation. Without scattering or beam divergence, an analytical posing of the problem as a simple integral predicts minima near a pitch of 1/n where n is an integer. A convolution-superposition dose calculator (TomoTherapy, Inc.) included all the physics needed to explore the ripple magnitude versus pitch and beam width. The results of the dose calculator and some benchmark measurements demonstrate that the ripple has sharp minima near p=0.86(1/n). The 0.86 factor is empirical and caused by a beam junctioning of the off-axis dose profiles which differ from the axial profiles as well as a long scatter tail of the profiles at depth. For very strong intensity modulation, the 0.86 factor may vary. The authors propose choosing particular minima pitches or using a second delivery that starts 180 deg off-phase from the first to reduce these ripples: 'Double threading'. For current typical pitches and beam widths, however, this effect is small and not clinically important for most situations. Certain extremely large field or high pitch cases, however, may benefit from mitigation of this effect

  9. Effects of Magnetic and Kinetic Helicities on the Growth of Magnetic Fields in Laminar and Turbulent Flows by Helical Fourier Decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Linkmann, Moritz; Sahoo, Ganapati; Biferale, Luca [Department of Physics and INFN, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, I-00133 Rome (Italy); McKay, Mairi; Berera, Arjun [School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, EH9 3FD, Edinburgh (United Kingdom)

    2017-02-10

    We present a numerical and analytical study of incompressible homogeneous conducting fluids using a helical Fourier representation. We analytically study both small- and large-scale dynamo properties, as well as the inverse cascade of magnetic helicity, in the most general minimal subset of interacting velocity and magnetic fields on a closed Fourier triad. We mainly focus on the dependency of magnetic field growth as a function of the distribution of kinetic and magnetic helicities among the three interacting wavenumbers. By combining direct numerical simulations of the full magnetohydrodynamics equations with the helical Fourier decomposition, we numerically confirm that in the kinematic dynamo regime the system develops a large-scale magnetic helicity with opposite sign compared to the small-scale kinetic helicity, a sort of triad-by-triad α -effect in Fourier space. Concerning the small-scale perturbations, we predict theoretically and confirm numerically that the largest instability is achived for the magnetic component with the same helicity of the flow, in agreement with the Stretch–Twist–Fold mechanism. Vice versa, in the presence of Lorentz feedback on the velocity, we find that the inverse cascade of magnetic helicity is mostly local if magnetic and kinetic helicities have opposite signs, while it is more nonlocal and more intense if they have the same sign, as predicted by the analytical approach. Our analytical and numerical results further demonstrate the potential of the helical Fourier decomposition to elucidate the entangled dynamics of magnetic and kinetic helicities both in fully developed turbulence and in laminar flows.

  10. Formation and sustainment of a very low aspect ratio tokamak using coaxial helicity injection (the Helicity Injected Torus [HIT] experiment)

    International Nuclear Information System (INIS)

    Jarboe, T.R.; Nelson, B.A.

    1992-01-01

    In the paper we will detail the progress of the HIT experiment construction, including the following components: preliminary data and interpretation; diagnostic systems; vacuum vessel and pumping system; helicity source and power supplies; toroidal field coil and power supply; data acquisition system; collaboration with general atomics, with a brief summary given on each

  11. Deflection-based method for seismic response analysis of concrete walls: Benchmarking of CAMUS experiment

    International Nuclear Information System (INIS)

    Basu, Prabir C.; Roshan, A.D.

    2007-01-01

    A number of shake table tests had been conducted on the scaled down model of a concrete wall as part of CAMUS experiment. The experiments were conducted between 1996 and 1998 in the CEA facilities in Saclay, France. Benchmarking of CAMUS experiments was undertaken as a part of the coordinated research program on 'Safety Significance of Near-Field Earthquakes' organised by International Atomic Energy Agency (IAEA). Technique of deflection-based method was adopted for benchmarking exercise. Non-linear static procedure of deflection-based method has two basic steps: pushover analysis, and determination of target displacement or performance point. Pushover analysis is an analytical procedure to assess the capacity to withstand seismic loading effect that a structural system can offer considering the redundancies and inelastic deformation. Outcome of a pushover analysis is the plot of force-displacement (base shear-top/roof displacement) curve of the structure. This is obtained by step-by-step non-linear static analysis of the structure with increasing value of load. The second step is to determine target displacement, which is also known as performance point. The target displacement is the likely maximum displacement of the structure due to a specified seismic input motion. Established procedures, FEMA-273 and ATC-40, are available to determine this maximum deflection. The responses of CAMUS test specimen are determined by deflection-based method and analytically calculated values compare well with the test results

  12. Exploring of PST-TBPM in Monitoring Bridge Dynamic Deflection in Vibration

    Science.gov (United States)

    Zhang, Guojian; Liu, Shengzhen; Zhao, Tonglong; Yu, Chengxin

    2018-01-01

    This study adopts digital photography to monitor bridge dynamic deflection in vibration. Digital photography used in this study is based on PST-TBPM (photographing scale transformation-time baseline parallax method). Firstly, a digital camera is used to monitor the bridge in static as a zero image. Then, the digital camera is used to monitor the bridge in vibration every three seconds as the successive images. Based on the reference system, PST-TBPM is used to calculate the images to obtain the bridge dynamic deflection in vibration. Results show that the average measurement accuracies are 0.615 pixels and 0.79 pixels in X and Z direction. The maximal deflection of the bridge is 7.14 pixels. PST-TBPM is valid in solving the problem-the photographing direction not perpendicular to the bridge. Digital photography used in this study can assess the bridge health through monitoring the bridge dynamic deflection in vibration. The deformation trend curves depicted over time also can warn the possible dangers.

  13. PR/VI North-South Deflections (DEFLEC96)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' surface deflection of the vertical grid for Puerto Rico and the Virgin Islands is distributed as the DEFLEC96 model. The computation used about 26,000...

  14. Hawaiian Islands East-West Deflections (DEFLEC96)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' surface deflection of the vertical grid for the Principal Hawaiian Islands is the DEFLEC96 model. The computation used about 61,000 terrestrial and marine...

  15. Lateral deflection of the SOL plasma during a giant ELM

    International Nuclear Information System (INIS)

    Landman, I.S.; Wuerz, H.

    2001-01-01

    In recent H-mode experiments at JET with giant ELMs a lateral deflection of hot tokamak plasma striking the divertor plate has been observed. This deflection can effect the divertor erosion caused by the hot plasma irradiation. Based on the MHD model for the vapor shield plasma and the hot plasma, the Seebeck effect is analyzed for explanation of the deflection. At t=-∞ both plasmas are at rest and separated by a boundary parallel to the target. The interaction between plasmas develops gradually ('adiabatically') as exp(t/t 0 ) with t 0 ∼10 2 μs the ELM duration time. At inclined impact of the magnetized hot plasma a toroidal current develops in the interaction zone of the plasmas. The JxB force accelerates the interacting plasmas in the lateral direction. The cold plasma motion essentially compensates the current. The magnitude of the hot plasma deflection is comparable to the observed one

  16. PR/VI East-West Deflections (DEFLEC96)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' surface deflection of the vertical grid for Puerto Rico and the Virgin Islands is distributed as the DEFLEC96 model. The computation used about 26,000...

  17. U.S. East-West Deflections (DEFLEC96)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' surface deflection of the vertical grid for the conterminous United States is the DEFLEC96 model. The computationused about 1.8 million terrestrial and...

  18. U.S. North-South Deflections (DEFLEC96)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' surface deflection of the vertical grid for the conterminous United States is the DEFLEC96 model. The computationused about 1.8 million terrestrial and...

  19. Hawaiian Islands North-South Deflections (DEFLEC96)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' surface deflection of the vertical grid for the Principal Hawaiian Islands is the DEFLEC96 model. The computation used about 61,000 terrestrial and marine...

  20. Theory of dynamics in long pulse helical plasmas

    International Nuclear Information System (INIS)

    Itoh, K.; Sanuki, H.; Toda, S.; Yokoyama, M.; Itoh, S.-I.; Yagi, M.; Fukuyama, A.

    2001-01-01

    Self-organized dynamics of toroidal helical plasma, which is induced by the nonlinear transport property, is discussed. Neoclassical ripple diffusion is a dominant mechanism that drives the radial electric field. The bifurcation nature of the electric field generation gives rise to the electric field domain interface, across which the electric field changes strongly. This domain interface is an origin of internal transport barrier in helical systems. This nonlinearity gives rise to the self-organized oscillations; the electric field pulsation is one of the examples. Based on the model of density limit, in which the competition between the transport loss and radiation loss is analyzed, dynamics near the density limit of helical systems is also discussed. (author)

  1. Catastrophic Disruption Threshold and Maximum Deflection from Kinetic Impact

    Science.gov (United States)

    Cheng, A. F.

    2017-12-01

    The use of a kinetic impactor to deflect an asteroid on a collision course with Earth was described in the NASA Near-Earth Object Survey and Deflection Analysis of Alternatives (2007) as the most mature approach for asteroid deflection and mitigation. The NASA DART mission will demonstrate asteroid deflection by kinetic impact at the Potentially Hazardous Asteroid 65803 Didymos in October, 2022. The kinetic impactor approach is considered to be applicable with warning times of 10 years or more and with hazardous asteroid diameters of 400 m or less. In principle, a larger kinetic impactor bringing greater kinetic energy could cause a larger deflection, but input of excessive kinetic energy will cause catastrophic disruption of the target, leaving possibly large fragments still on collision course with Earth. Thus the catastrophic disruption threshold limits the maximum deflection from a kinetic impactor. An often-cited rule of thumb states that the maximum deflection is 0.1 times the escape velocity before the target will be disrupted. It turns out this rule of thumb does not work well. A comparison to numerical simulation results shows that a similar rule applies in the gravity limit, for large targets more than 300 m, where the maximum deflection is roughly the escape velocity at momentum enhancement factor β=2. In the gravity limit, the rule of thumb corresponds to pure momentum coupling (μ=1/3), but simulations find a slightly different scaling μ=0.43. In the smaller target size range that kinetic impactors would apply to, the catastrophic disruption limit is strength-controlled. A DART-like impactor won't disrupt any target asteroid down to significantly smaller size than the 50 m below which a hazardous object would not penetrate the atmosphere in any case unless it is unusually strong.

  2. TIME EVOLUTION OF CORONAL MAGNETIC HELICITY IN THE FLARING ACTIVE REGION NOAA 10930

    International Nuclear Information System (INIS)

    Park, Sung-Hong; Jing, Ju; Wang Haimin; Chae, Jongchul; Tan, Changyi

    2010-01-01

    To study the three-dimensional (3D) magnetic field topology and its long-term evolution associated with the X3.4 flare of 2006 December 13, we investigate the coronal relative magnetic helicity in the flaring active region (AR) NOAA 10930 during the time period of December 8-14. The coronal helicity is calculated based on the 3D nonlinear force-free magnetic fields reconstructed by the weighted optimization method of Wiegelmann, and is compared with the amount of helicity injected through the photospheric surface of the AR. The helicity injection is determined from the magnetic helicity flux density proposed by Pariat et al. using Solar and Heliospheric Observatory/Michelson Doppler Imager magnetograms. The major findings of this study are the following. (1) The time profile of the coronal helicity shows a good correlation with that of the helicity accumulation by injection through the surface. (2) The coronal helicity of the AR is estimated to be -4.3 x 10 43 Mx 2 just before the X3.4 flare. (3) This flare is preceded not only by a large increase of negative helicity, -3.2 x 10 43 Mx 2 , in the corona over ∼1.5 days but also by noticeable injections of positive helicity through the photospheric surface around the flaring magnetic polarity inversion line during the time period of the channel structure development. We conjecture that the occurrence of the X3.4 flare is involved with the positive helicity injection into an existing system of negative helicity.

  3. Investigation of Horizontal Velocity Fields in Stirred Vessels with Helical Coils by PIV

    Directory of Open Access Journals (Sweden)

    Volker Bliem

    2014-01-01

    Full Text Available Horizontal velocity flow fields were measured by particle image velocimetry for a stirred vessel with baffles and two helical coils for enlargement of heat transfer area. The investigation was carried out in a cylindrical vessel with flat base and two different stirrers (radial-flow Rushton turbine and axial-flow propeller stirrer. Combined velocity plots for flow fields at different locations are presented. It was found that helical coils change the flow pattern significantly. Measurements for the axial-flow Rushton turbine showed a strong deflection by the coils, leading to a mainly tangential flow pattern. Behind baffles large areas of unused heat transfer area were found. First results for the axial-flow propeller reveal an extensive absence of fluid movement in the horizontal plane. Improved design considerations for enhanced heat transfer by more compatible equipment compilation are proposed.

  4. Influence of bracket-slot design on the forces released by superelastic nickel-titanium alignment wires in different deflection configurations.

    Science.gov (United States)

    Nucera, Riccardo; Gatto, Elda; Borsellino, Chiara; Aceto, Pasquale; Fabiano, Francesca; Matarese, Giovanni; Perillo, Letizia; Cordasco, Giancarlo

    2014-05-01

    To evaluate how different bracket-slot design characteristics affect the forces released by superelastic nickel-titanium (NiTi) alignment wires at different amounts of wire deflection. A three-bracket bending and a classic-three point bending testing apparatus were used to investigate the load-deflection properties of one superelastic 0.014-inch NiTi alignment wire in different experimental conditions. The selected NiTi archwire was tested in association with three bracket systems: (1) conventional twin brackets with a 0.018-inch slot, (2) a self-ligating bracket with a 0.018-inch slot, and (3) a self-ligating bracket with a 0.022-inch slot. Wire specimens were deflected at 2 mm and 4 mm. Use of a 0.018-inch slot bracket system, in comparison with use of a 0.022-inch system, increases the force exerted by the superelastic NiTi wires at a 2-mm deflection. Use of a self-ligating bracket system increases the force released by NiTi wires in comparison with the conventional ligated bracket system. NiTi wires deflected to a different maximum deflection (2 mm and 4 mm) release different forces at the same unloading data point (1.5 mm). Bracket design, type of experimental test, and amount of wire deflection significantly affected the amount of forces released by superelastic NiTi wires (Pwire's load during alignment.

  5. Cuspal Deflection of Premolars Restored with Bulk-Fill Composite Resins.

    Science.gov (United States)

    Behery, Haytham; El-Mowafy, Omar; El-Badrawy, Wafa; Saleh, Belal; Nabih, Sameh

    2016-01-01

    This in vitro study compared cuspal deflection of premolars restored with three bulk-fill composite resins to that of incrementally-restored ones with a low-shrinkage silorane-based restorative material. Forty freshly-extracted intact human upper premolars were used. Reference points at buccal and palatal cusp tips were acid-etched and composite rods were horizontally bonded to them (TPH-Spectra-HV, Dentsply). Two acrylic resin guiding paths were made for each premolar to guide beaks of a digital micrometer used for cuspal deflection measurements. Standardized MOD cavities, 3 mm wide bucco-lingually and 3.5 mm deep, were prepared on each premolar. Prepared teeth were then equally divided into four groups (n = 10) and each group was assigned to one of four composite resin (QuiXX, Dentsply; X-tra fil, Voco; Tetric EvoCeram Bulk Fill, Ivoclar Vivadent; low-shrinkage Filtek LS, 3M/ESPE). Adper Single Bond-Plus, 3M/ESPE was used with all bulk-fill restoratives. LS-System Adhesive, 3M/ESPE was used with Filtek LS. For each prepared premolar, cuspal deflection was measured in microns as the difference between two readings between reference points before and after restoration completion. Means and SDs were calculated and data statistically-analyzed using One-way ANOVA and Tukey's test. Filtek LS showed the lowest mean cuspal deflection value 6.4(0.84)μm followed by Tetric EvoCeram Bulk Fill 10.1(1.2) μm and X-tra fil 12.4(1.35)μm, while QuiXX showed the highest mean 13(1.05)μm. ANOVA indicated significant difference among mean values of groups (p composite resins tested. Filtek LS had the lowest significant mean cuspal deflection in comparison to all tested bulk-fill restoratives. The use of Tetric EvoCeram Bulk fill composite resin restorative for class II MOD cavities resulted in reduced cuspal deflection in comparison to the two other bulk-fill composite resins tested. The silorane-based Filtek LS restorative resulted in the least cuspal deflection in

  6. Quality assurance of a helical tomotherapy machine

    International Nuclear Information System (INIS)

    Fenwick, J D; Tome, W A; Jaradat, H A; Hui, S K; James, J A; Balog, J P; DeSouza, C N; Lucas, D B; Olivera, G H; Mackie, T R; Paliwal, B R

    2004-01-01

    Helical tomotherapy has been developed at the University of Wisconsin, and 'Hi-Art II' clinical machines are now commercially manufactured. At the core of each machine lies a ring-gantry-mounted short linear accelerator which generates x-rays that are collimated into a fan beam of intensity-modulated radiation by a binary multileaf, the modulation being variable with gantry angle. Patients are treated lying on a couch which is translated continuously through the bore of the machine as the gantry rotates. Highly conformal dose-distributions can be delivered using this technique, which is the therapy equivalent of spiral computed tomography. The approach requires synchrony of gantry rotation, couch translation, accelerator pulsing and the opening and closing of the leaves of the binary multileaf collimator used to modulate the radiation beam. In the course of clinically implementing helical tomotherapy, we have developed a quality assurance (QA) system for our machine. The system is analogous to that recommended for conventional clinical linear accelerator QA by AAPM Task Group 40 but contains some novel components, reflecting differences between the Hi-Art devices and conventional clinical accelerators. Here the design and dosimetric characteristics of Hi-Art machines are summarized and the QA system is set out along with experimental details of its implementation. Connections between this machine-based QA work, pre-treatment patient-specific delivery QA and fraction-by-fraction dose verification are discussed

  7. Observing Bridge Dynamic Deflection in Green Time by Information Technology

    Science.gov (United States)

    Yu, Chengxin; Zhang, Guojian; Zhao, Yongqian; Chen, Mingzhi

    2018-01-01

    As traditional surveying methods are limited to observe bridge dynamic deflection; information technology is adopted to observe bridge dynamic deflection in Green time. Information technology used in this study means that we use digital cameras to photograph the bridge in red time as a zero image. Then, a series of successive images are photographed in green time. Deformation point targets are identified and located by Hough transform. With reference to the control points, the deformation values of these deformation points are obtained by differencing the successive images with a zero image, respectively. Results show that the average measurement accuracies of C0 are 0.46 pixels, 0.51 pixels and 0.74 pixels in X, Z and comprehensive direction. The average measurement accuracies of C1 are 0.43 pixels, 0.43 pixels and 0.67 pixels in X, Z and comprehensive direction in these tests. The maximal bridge deflection is 44.16mm, which is less than 75mm (Bridge deflection tolerance value). Information technology in this paper can monitor bridge dynamic deflection and depict deflection trend curves of the bridge in real time. It can provide data support for the site decisions to the bridge structure safety.

  8. Post mitigation impact risk analysis for asteroid deflection demonstration missions

    Science.gov (United States)

    Eggl, Siegfried; Hestroffer, Daniel; Thuillot, William; Bancelin, David; Cano, Juan L.; Cichocki, Filippo

    2015-08-01

    Even though mankind believes to have the capabilities to avert potentially disastrous asteroid impacts, only the realization of mitigation demonstration missions can validate this claim. Such a deflection demonstration attempt has to be cost effective, easy to validate, and safe in the sense that harmless asteroids must not be turned into potentially hazardous objects. Uncertainties in an asteroid's orbital and physical parameters as well as those additionally introduced during a mitigation attempt necessitate an in depth analysis of deflection mission designs in order to dispel planetary safety concerns. We present a post mitigation impact risk analysis of a list of potential kinetic impactor based deflection demonstration missions proposed in the framework of the NEOShield project. Our results confirm that mitigation induced uncertainties have a significant influence on the deflection outcome. Those cannot be neglected in post deflection impact risk studies. We show, furthermore, that deflection missions have to be assessed on an individual basis in order to ensure that asteroids are not inadvertently transported closer to the Earth at a later date. Finally, we present viable targets and mission designs for a kinetic impactor test to be launched between the years 2025 and 2032.

  9. Subnanosecond pulsing of an 1 MeV ELIT electron accelerator by beam deflection

    International Nuclear Information System (INIS)

    Vasserman, S.B.; Kuzenko, V.; Mehnert, R.; Hermann, R.

    1984-01-01

    Operation principle and performance of a beam deflection system developed for subnanosecond pulsing of an 1 MeV ELIT resonance transformer accelerator are described. Using this system a minimum pulse duration of 0.5 ns (FWHM) and a dose per pulse of about 20 Gy were obtained. As an example the fluorescence of cyclohexane excited by the subnanosecond electron pulse was measured. (author)

  10. Experimental Study of Hypersonic Inflatable Aerodynamic Decelerator (HIAD) Aeroshell with Axisymmetric Surface Deflection Patterns

    Science.gov (United States)

    Hollis, Brian R.; Hollingsworth, Kevin E.

    2017-01-01

    A wind tunnel test program was conducted to obtain aeroheating environment data on Hypersonic Inflatable Aerodynamic Decelerator aeroshells with flexible thermal protection systems. Data were obtained on a set of rigid wind tunnel models with surface deflection patterns of various heights that simulated a range of potential in-flight aeroshell deformations. Wind tunnel testing was conducted at Mach 6 at unit Reynolds numbers from 2.1 × 10(exp 6)/ft to 8.3 × 10(exp 6)/ft and angles of attack from 0 deg to 18 deg. Boundary-layer transition onset and global surface heating distribution measurements were performed using phosphor thermography and flow field images were obtained through schlieren photography. Surface deflections were found to both promote early transition of the boundary layer and to augment heating levels for both laminar and turbulent flows. A complimentary computational flow field study was also performed to provide heating predictions for comparison with the measurements as well as boundary layer flow field properties for use in correlating the data. Correlations of the wind tunnel data were developed to predict deflection effects on boundary layer transition and surface heating and were applied to both the wind tunnel test conditions and to the trajectory of NASA's successful IRVE-3 flight test. In general, the correlations produced at least qualitative agreement with the wind tunnel data, although the heating levels were underpredicted for some of the larger surface deflections. For the flight conditions, the correlations suggested that peak heating levels on the leeward side conical flank of the IRVE-3 vehicle may have exceeded those at nose for times late in the trajectory after the peak heating time point. However, the flight estimates were based on a conservative assumption of surface deflection magnitude (i.e., larger) than likely was produced in flight.

  11. A novel approach to calculate inductance and analyze magnetic flux density of helical toroidal coil applicable to Superconducting Magnetic Energy Storage systems (SMES)

    International Nuclear Information System (INIS)

    Alizadeh Pahlavani, M.R.; Shoulaie, A.

    2010-01-01

    In this paper, formulas are proposed for the self and mutual inductance calculations of the helical toroidal coil (HTC) by the direct and indirect methods at superconductivity conditions. The direct method is based on the Neumann's equation and the indirect approach is based on the toroidal and the poloidal components of the magnetic flux density. Numerical calculations show that the direct method is more accurate than the indirect approach at the expense of its longer computational time. Implementation of some engineering assumptions in the indirect method is shown to reduce the computational time without loss of accuracy. Comparison between the experimental measurements and simulated results for inductance, using the direct and the indirect methods indicates that the proposed formulas have high reliability. It is also shown that the self inductance and the mutual inductance could be calculated in the same way, provided that the radius of curvature is >0.4 of the minor radius, and that the definition of the geometric mean radius in the superconductivity conditions is used. Plotting contours for the magnetic flux density and the inductance show that the inductance formulas of helical toroidal coil could be used as the basis for coil optimal design. Optimization target functions such as maximization of the ratio of stored magnetic energy with respect to the volume of the toroid or the conductor's mass, the elimination or the balance of stress in some coordinate directions, and the attenuation of leakage flux could be considered. The finite element (FE) approach is employed to present an algorithm to study the three-dimensional leakage flux distribution pattern of the coil and to draw the magnetic flux density lines of the HTC. The presented algorithm, due to its simplicity in analysis and ease of implementation of the non-symmetrical and three-dimensional objects, is advantageous to the commercial software such as ANSYS, MAXWELL, and FLUX. Finally, using the

  12. Gynecological applications of helical CT using SmartPrep

    Energy Technology Data Exchange (ETDEWEB)

    Sakurada, Akira; Kakizaki, Dai; Abe, Kimihiko [Tokyo Medical Coll. (Japan)

    1999-11-01

    SmartPrep is software program for scanning a given region of interest (ROI) at optimal contrast density. An operator can arbitrarily define ROI and preset the CT value at which scanning should be started. After the injection of a contrast medium, system conducts continuous monitoring of the ROI and the operator starts helical scanning of the planned region when the present CT value has been reached. In comparison with conventional helical CT that requires a period of time from the beginning of contrast medium injection to the beginning of scanning, SmartPrep minimizes personal error and better depicts the artery-predominant phase under optimal conditions. In this study we examine the usefulness of contrast-enhanced helical CT using SmartPrep in the evaluation of gynecological disease. When the contrast medium was injected into the dorsal vein of the hand at a rate of 3 ml/sec, strong staining of pelvic arteries was observed in the CT images started at 17 to 23 sec after injection. The early-phase helical CT obtained under these conditions provided good depiction of lesions in cases of placenta accreta and invasive mole, as well as clear demonstration of tumor angiogenesis and evaluation of laterality in cases of cervical cancer. Comparison of the early and delayed phase also facilitated easier evaluation of lymph nodes than conventional comparison of simple and contrast-enhanced CT. The results thus suggest the usefulness of contrast-enhanced helical CT using SmartPrep in gynecology. (author)

  13. Directed energy deflection laboratory measurements of common space based targets

    Science.gov (United States)

    Brashears, Travis; Lubin, Philip; Hughes, Gary B.; Meinhold, Peter; Batliner, Payton; Motta, Caio; Madajian, Jonathan; Mercer, Whitaker; Knowles, Patrick

    2016-09-01

    We report on laboratory studies of the effectiveness of directed energy planetary defense as a part of the DE-STAR (Directed Energy System for Targeting of Asteroids and exploRation) program. DE-STAR and DE-STARLITE are directed energy "stand-off" and "stand-on" programs, respectively. These systems consist of a modular array of kilowatt-class lasers powered by photovoltaics, and are capable of heating a spot on the surface of an asteroid to the point of vaporization. Mass ejection, as a plume of evaporated material, creates a reactionary thrust capable of diverting the asteroid's orbit. In a series of papers, we have developed a theoretical basis and described numerical simulations for determining the thrust produced by material evaporating from the surface of an asteroid. In the DESTAR concept, the asteroid itself is used as the deflection "propellant". This study presents results of experiments designed to measure the thrust created by evaporation from a laser directed energy spot. We constructed a vacuum chamber to simulate space conditions, and installed a torsion balance that holds a common space target sample. The sample is illuminated with a fiber array laser with flux levels up to 60 MW/m2 , which allows us to simulate a mission level flux but on a small scale. We use a separate laser as well as a position sensitive centroid detector to readout the angular motion of the torsion balance and can thus determine the thrust. We compare the measured thrust to the models. Our theoretical models indicate a coupling coefficient well in excess of 100 μN/Woptical, though we assume a more conservative value of 80 μN/Woptical and then degrade this with an optical "encircled energy" efficiency of 0.75 to 60 μN/Woptical in our deflection modeling. Our measurements discussed here yield about 45 μN/Wabsorbed as a reasonable lower limit to the thrust per optical watt absorbed. Results vary depending on the material tested and are limited to measurements of 1 axis, so

  14. Helicity formalism and spin effects

    International Nuclear Information System (INIS)

    Anselmino, M.; Caruso, F.; Piovano, U.

    1990-01-01

    The helicity formalism and the technique to compute amplitudes for interaction processes involving leptons, quarks, photons and gluons are reviewed. Explicit calculations and examples of exploitation of symmetry properties are shown. The formalism is then applied to the discussion of several hadronic processes and spin effects: the experimental data, when related to the properties of the elementary constituent interactions, show many not understood features. Also the nucleon spin problem is briefly reviewed. (author)

  15. Dosimetric aspects of breast radiotherapy with three-dimensional and intensity-modulated radiotherapy helical tomotherapy planning modules

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Poonam [Department of Human Oncology, University of Wisconsin-Madison, Madison, WI (United States); Service of Radiation Therapy, University of Wisconsin Aspirus Cancer Center, Wisconsin Rapids, WI (United States); Yan, Yue, E-mail: yyan5@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX (United States); Ignatowski, Tasha [Service of Radiation Therapy, University of Wisconsin Aspirus Cancer Center, Wisconsin Rapids, WI (United States); Olson, Anna [Department of Human Oncology, University of Wisconsin-Madison, Madison, WI (United States); Service of Radiation Therapy, University of Wisconsin Aspirus Cancer Center, Wisconsin Rapids, WI (United States)

    2017-04-01

    In this work, we investigated the dosimetric differences between the intensity-modulated radiotherapy (IMRT) plans and the three-dimensional (3D) helical plans based on the TomoTherapy system. A total of 15 patients with supine setup were randomly selected from the data base. For patients with lumpectomy planning target volume (PTV), regional lymph nodes were also included as part of the target. For dose sparing, the significant differences between the helical IMRT and helical 3D were only found in the heart and contralateral breast. For the dose to the heart, helical IMRT reduced the maximum point dose by 6.98 Gy compared to the helical 3D plan (p = 0.01). For contralateral breast, the helical IMRT plans significantly reduced the maximum point dose by 5.6 Gy compared to the helical 3D plan. However, compared to the helical 3D plan, the helical IMRT plan increased the volume for lower dose (13.08% increase in V{sub 5} {sub Gy}, p = 0.01). In general, there are no significant differences in dose sparing between helical IMRT and helical 3D plans.

  16. Dosimetric aspects of breast radiotherapy with three-dimensional and intensity-modulated radiotherapy helical tomotherapy planning modules

    International Nuclear Information System (INIS)

    Yadav, Poonam; Yan, Yue; Ignatowski, Tasha; Olson, Anna

    2017-01-01

    In this work, we investigated the dosimetric differences between the intensity-modulated radiotherapy (IMRT) plans and the three-dimensional (3D) helical plans based on the TomoTherapy system. A total of 15 patients with supine setup were randomly selected from the data base. For patients with lumpectomy planning target volume (PTV), regional lymph nodes were also included as part of the target. For dose sparing, the significant differences between the helical IMRT and helical 3D were only found in the heart and contralateral breast. For the dose to the heart, helical IMRT reduced the maximum point dose by 6.98 Gy compared to the helical 3D plan (p = 0.01). For contralateral breast, the helical IMRT plans significantly reduced the maximum point dose by 5.6 Gy compared to the helical 3D plan. However, compared to the helical 3D plan, the helical IMRT plan increased the volume for lower dose (13.08% increase in V 5 Gy , p = 0.01). In general, there are no significant differences in dose sparing between helical IMRT and helical 3D plans.

  17. New reconstruction algorithm in helical-volume CT

    International Nuclear Information System (INIS)

    Toki, Y.; Rifu, T.; Aradate, H.; Hirao, Y.; Ohyama, N.

    1990-01-01

    This paper reports on helical scanning that is an application of continuous scanning CT to acquire volume data in a short time for three-dimensional study. In a helical scan, the patient couch sustains movement during continuous-rotation scanning and then the acquired data is processed to synthesize a projection data set of vertical section by interpolation. But the synthesized section is not thin enough; also, the image may have artifacts caused by couch movement. A new reconstruction algorithm that helps resolve such problems has been developed and compared with the ordinary algorithm. The authors constructed a helical scan system based on TCT-900S, which can perform 1-second rotation continuously for 30 seconds. The authors measured section thickness using both algorithms on an AAPM phantom, and we also compared degree of artifacts on clinical data

  18. Effect of loss cone on confinement in toroidal helical device

    International Nuclear Information System (INIS)

    Itoh, K.; Itoh, S.-I.; Fukuyama, A.; Hanatani, K.

    1988-12-01

    Analytical estimation is given on the loss cone in the toroidal helical devices in the presence of the radial electric field and the modulation of the helical ripple. The minimum energy of particles entering the loss cone is calculated. The modulation is not always effective in reducing the loss in the presence of the radial electric field. The plasma loss due to the loss cone is estimated in the collisionless limit. The radial electric field is estimated in the presence of the loss cone. It is found that the transition to the solution with positive radial electric field, which is necessary to achieve the high-ion-temperature mode, becomes difficult. This difficulty is large for the systems with the small helical ripple. (author)

  19. Imploding to equilibrium of helically symmetric theta pinches

    International Nuclear Information System (INIS)

    Sharky, N.N.

    1978-01-01

    The time-dependent, single-fluid, dissipative magnetohydrodynamic equations are solved in helical coordinates (r,phi), where phi = THETA-kz, k = 2π/L and L is the periodicity length in the z-direction. The two-dimensional numerical calculations simulate theta pinches which have an l = 1 helical field added to them. Given the applied magnetic fields and the initial state of the plasma, we study the time evolution of the system. The plasma is found to experience two kinds of oscillations, occurring on different time scales. These are the radial compression oscillations, and the slower helical oscillations of the plasma column. The plasma motion is followed until these oscillations disappear and an equilibrium is nearly reached. Hence given the amplitude and the rise time of the applied magnetic fields, the calculations allow one to relate the initial state of a cold, homogeneous plasma to its final equilibrium state where it is heated and compressed

  20. Helical Antimicrobial Sulfono- {gamma} -AApeptides

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yaqiong; Wu, Haifan; Teng, Peng; Bai, Ge; Lin, Xiaoyang; Zuo, Xiaobing; Cao, Chuanhai; Cai, Jianfeng

    2015-06-11

    Host-defense peptides (HDPs) such as magainin 2 have emerged as potential therapeutic agents combating antibiotic resistance. Inspired by their structures and mechanism of action, herein we report the fi rst example of antimicrobial helical sulfono- γ - AApeptide foldamers. The lead molecule displays broad-spectrum and potent antimicrobial activity against multi-drug-resistant Gram- positive and Gram-negative bacterial pathogens. Time-kill studies and fl uorescence microscopy suggest that sulfono- γ -AApeptides eradicate bacteria by taking a mode of action analogous to that of HDPs. Clear structure - function relationships exist in the studied sequences. Longer sequences, presumably adopting more-de fi ned helical structures, are more potent than shorter ones. Interestingly, the sequence with less helical propensity in solution could be more selective than the stronger helix-forming sequences. Moreover, this class of antimicrobial agents are resistant to proteolytic degradation. These results may lead to the development of a new class of antimicrobial foldamers combating emerging antibiotic-resistant pathogens.

  1. Magnetic helicity and active filament configuration

    Science.gov (United States)

    Romano, P.; Zuccarello, F.; Poedts, S.; Soenen, A.; Zuccarello, F. P.

    2009-11-01

    Context: The role of magnetic helicity in active filament formation and destabilization is still under debate. Aims: Although active filaments usually show a sigmoid shape and a twisted configuration before and during their eruption, it is unclear which mechanism leads to these topologies. In order to provide an observational contribution to clarify these issues, we describe a filament evolution whose characteristics seem to be directly linked to the magnetic helicity transport in corona. Methods: We applied different methods to determine the helicity sign and the chirality of the filament magnetic field. We also computed the magnetic helicity transport rate at the filament footpoints. Results: All the observational signatures provided information on the positive helicity and sinistral chirality of the flux rope containing the filament material: its forward S shape, the orientation of its barbs, the bright and dark threads at 195 Å. Moreover, the magnetic helicity transport rate at the filament footpoints showed a clear accumulation of positive helicity. Conclusions: The study of this event showed a correspondence between several signatures of the sinistral chirality of the filament and several evidences of the positive magnetic helicity of the filament magnetic field. We also found that the magnetic helicity transported along the filament footpoints showed an increase just before the change of the filament shape observed in Hα images. We argued that the photospheric regions where the filament was rooted might be the preferential ways where the magnetic helicity was injected along the filament itself and where the conditions to trigger the eruption were yielded.

  2. Calibration and compensation of deflections and compliances in remote handling equipment configurations

    International Nuclear Information System (INIS)

    Kivelae, Tuomo; Saarinen, H.; Mattila, J.; Haemaelaeinen, V.; Siuko, M.; Semeraro, L.

    2011-01-01

    This paper presents a generic method of calibrating and compensating remote handling system configurations subject to manufacturing and assembly tolerances, deflections and compliances. A method consists of kinematic part and non-kinematic part. A kinematic calibration algorithm is presented for finding the values of kinematic model errors by measuring the end-effector Cartesian position. This is a conventional way to calibrate industrial robots. However, in this case the kinematic calibration is not able to compensate flaws fully due to large deflections and compliances caused by a massive Cassette payload (approx. 9 ton). Positioning error at the furthest point of the cassette before any compensation was 80 mm. Therefore, extra compensation must be introduced in addition to a kinematic calibration. A kinematic calibration together with an extra compensation is a demanding task to carry out. The resulting complex compensation function has to be such that it can be implemented in real-time Cassette Multifunctional Mover (CMM) control system software.

  3. Influence of bending deflection rate on properties of fibrous mortar

    Directory of Open Access Journals (Sweden)

    Metwally Abd Allah Abd el Aty

    2013-04-01

    Full Text Available Selection of the construction materials is affected by many factors including their properties under the applied loads. Loading rate is considered as a very important parameter which influences the behavior of the materials. Fibrous concrete is commonly used in applications in which the loading rate exceeds quasi static conditions by a large margin. This paper investigates the influence of flexural loading rate on the performance of fibrous concrete prisms in flexure. Two hundred and fifty two prisms include fibrous concrete and control specimens were prepared and tested. Fiber type, fiber dosage and flexural loading rate were the main parameters considered in this study. Two types of fibers were investigated namely polypropylene fibers and glass fibers. Three dosages of fiber volume fractions were implemented as 0.5%, 1.0% and 2.0%. A total of 12 different rates of displacement (0.0039 up to 8 mm/s for load application were conducted. A computer controlled universal testing machine provided with data acquisition system capable of performing 1000 loop per second was used. Load–central deflection, flexural strength and toughness were the evaluated properties for the investigated specimens. The results indicated that the flexure strength values exhibited loading rate dependence not only for the control mix but also for the investigated fibrous mortar mixes. Also the performance in flexure varied substantially not only with loading rate but with fiber type and fiber volume fractions as well.

  4. Load-deflection characteristics of small bore insulated pipe clamps

    International Nuclear Information System (INIS)

    Severud, L.K.; Clark, G.L.

    1982-01-01

    High temperature LMFBR piping is subject to rapid temperature changes during transient events. Typically, this pipe is supported by specially designed insulated pipe clamps to prevent excessive thermal stress from developing during these transients. The special insulated clamps used on both FFTF and CRBR piping utilize a Belleville spring arrangement to compensate for pipe thermal expansion. Analysis indicates that this produces a non-linear, directionally sensitive clamp spring rate. Since these spring rates influence the seismic response of a supported piping system, it was deemed necessary to evaluate them further by test. This has been accomplished for the FFTF clamps. A more standard insulated pipe clamp, which does not incorporate Belleville springs to accommodate thermal expansion, was also tested. This type clamp is simple in design, and economically attractive. It may have wide application prospects for use in LMFBR small bore auxiliary piping operating at temperatures below 427 0 C. Load deflection tests were conducted on 2.54 CM and 7.62 CM diameter samples of these commercial clamps

  5. Virtual machining considering dimensional, geometrical and tool deflection errors in three-axis CNC milling machines

    OpenAIRE

    Soori, Mohsen; Arezoo, Behrooz; Habibi, Mohsen

    2014-01-01

    Virtual manufacturing systems can provide useful means for products to be manufactured without the need of physical testing on the shop floor. As a result, the time and cost of part production can be decreased. There are different error sources in machine tools such as tool deflection, geometrical deviations of moving axis and thermal distortions of machine tool structures. Some of these errors can be decreased by controlling the machining process and environmental parameters. However other e...

  6. Virtual machining considering dimensional, geometrical and tool deflection errors in three-axis CNC milling machines

    OpenAIRE

    Soori, Mohsen; Arezoo, Behrooz; Habibi, Mohsen

    2016-01-01

    Virtual manufacturing systems can provide useful means for products to be manufactured without the need of physical testing on the shop floor. As a result, the time and cost of part production can be decreased. There are different error sources in machine tools such as tool deflection, geometrical deviations of moving axis and thermal distortions of machine tool structures. Some of these errors can be decreased by controlling the machining process and environmental parameters. However other e...

  7. All-optical optoacoustic microscopy based on probe beam deflection technique

    OpenAIRE

    Maswadi, Saher M.; Ibey, Bennett L.; Roth, Caleb C.; Tsyboulski, Dmitri A.; Beier, Hope T.; Glickman, Randolph D.; Oraevsky, Alexander A.

    2016-01-01

    Optoacoustic (OA) microscopy using an all-optical system based on the probe beam deflection technique (PBDT) for detection of laser-induced acoustic signals was investigated as an alternative to conventional piezoelectric transducers. PBDT provides a number of advantages for OA microscopy including (i) efficient coupling of laser excitation energy to the samples being imaged through the probing laser beam, (ii) undistorted coupling of acoustic waves to the detector without the need for separa...

  8. Toward Identifying Needed Investments in Modeling and Simulation Tools for NEO Deflection Planning

    Science.gov (United States)

    Adams, Robert B.

    2009-01-01

    Its time: a) To bring planetary scientists, deflection system investigators and vehicle designers together on the characterization/mitigation problem. b) To develop a comprehensive trade space of options. c) To trade options under a common set of assumptions and see what comparisons on effectiveness can be made. d) To explore the synergy that can be had with proposed scientific and exploration architectures while interest in NEO's are at an all time high.

  9. Hamiltonian theory of vacuum helical torus lines of magnetic force

    International Nuclear Information System (INIS)

    Gnudi, Giovanni; Hatori, Tadatsugu

    1994-01-01

    For making plasma into equilibrium state, the lines of magnetic force must have magnetic surfaces. However in a helical system, space is divided into the region having magnetic surface structure and the region that does not have it. Accordingly, it is an important basic research for the plasma confinement in a helical system to examine where is the boundary of both regions and how is the large area structure of the lines of magnetic force in the boundary region. The lines of magnetic force can be treated as a Hamilton mechanics system, and it has been proved that the Hamiltonian for the lines of magnetic force can be expressed by a set of canonical variables and the function of time. In this research, the Hamiltonian that describes the lines of magnetic force of helical system torus coordination in vacuum was successfully determined concretely. Next, the development of new linear symplectic integration method was carried out. The important supports for the theory of determining Hamiltonian are Lie transformation and paraxial expansion. The procedure is explained. In Appendix, Lie transformation, Hamiltonian for the lines of magnetic force, magnetic potential, Taylor expansion of the potential, cylindrical limit approximation, helical toroidal potential and integrable model are described. (K.I.)

  10. New formulae for magnetic relative helicity and field line helicity

    Science.gov (United States)

    Aly, Jean-Jacques

    2018-01-01

    We consider a magnetic field {B} occupying the simply connected domain D and having all its field lines tied to the boundary S of D. We assume here that {B} has a simple topology, i.e., the mapping {M} from positive to negative polarity areas of S associating to each other the two footpoints of any magnetic line, is continuous. We first present new formulae for the helicity H of {B} relative to a reference field {{B}}r having the same normal component {B}n on S, and for its field line helicity h relative to a reference vector potential {{C}}r of {{B}}r. These formulae make immediately apparent the well known invariance of these quantities under all the ideal MHD deformations that preserve the positions of the footpoints on S. They express indeed h and H either in terms of {M} and {B}n, or in terms of the values on S of a pair of Euler potentials of {B}. We next show that, for a specific choice of {{C}}r, the field line helicity h of {B} fully characterizes the magnetic mapping {M} and then the topology of the lines. Finally, we give a formula that describes the rate of change of h in a situation where the plasma moves on the perfectly conducting boundary S without changing {B}n and/or non-ideal processes, described by an unspecified term {N} in Ohm’s law, are at work in some parts of D.

  11. Improvements in or relating to electron beam deflection arrangements

    International Nuclear Information System (INIS)

    Bull, E.W.

    1979-01-01

    This relates to the deflection of ribbon-like electron beams in X-ray tubes particularly in radiographic equipment. The X-ray tubes includes a source of a ribbon-shaped beam of electrons relatively narrow in a direction orthogonal to the direction of the beam and relatively wide in a second orthogonal direction. An elongated target projects X-rays about a chosen direction in response to the incident beam. There is a means (toroidal former, deflection coils or plates) for deflecting the electron beam to scan the region of incidence along the target and correction means for changing the shape of the electron beam depending on the deflection so that the region of incidence of the deflected beam remains a linear region substantially parallel to the region of incidence of the undeflected beam. The apparatus for this, and variations, are described. A medical radiography unit (computerise axial tomography) including the X-ray tube described is also detailed. (U.K.)

  12. Development of sacrificial support fixture using deflection analysis

    Science.gov (United States)

    Ramteke, Ashwini M.; Ashtankar, Kishor M.

    2018-04-01

    Sacrificial support fixtures are the structures used to hold the part during machining while rotating the part about the fourth axis of CNC machining. In Four axis CNC machining part is held in a indexer which is rotated about the fourth axis of rotation. So using traditional fixturing devices to hold the part during machining such as jigs, v blocks and clamping plates needs a several set ups, manufacturing time which increase the cost associated with it. Since the part is rotated about the axis of rotation in four axis CNC machining so using traditional fixturing devices to hold the part while machining we need to reorient the fixture each time for particular orientation of part about the axis of rotation. So our proposed methodology of fixture design eliminates the cost associate with the complicated fixture design for customized parts which in turn reduces the time of manufacturing of the fixtures. But while designing the layout of the fixtures it is found out that the machining the part using four axis CNC machining the accurate machining of the part is directly proportional to the deflection produced in a part. So to machine an accurate part the deflection produced in a part should be minimum. We assume that the deflection produced in a part is a result of the deflection produced in a sacrificial support fixture while machining. So this paper provides the study of the deflection checking in a part machined using sacrificial support fixture by using FEA analysis.

  13. Divertors for Helical Devices: Concepts, Plans, Results, and Problems

    International Nuclear Information System (INIS)

    Koenig, R.; Grigull, P.; McCormick, K.

    2004-01-01

    With Large Helical Device (LHD) and Wendelstein 7-X (W7-X), the development of helical devices is now taking a large step forward on the path to a steady-state fusion reactor. Important issues that need to be settled in these machines are particle flux and heat control and the impact of divertors on plasma performance in future continuously burning fusion plasmas. The divertor concepts that will initially be explored in these large machines were prepared in smaller-scale devices like Heliotron E, Compact Helical System (CHS), and Wendelstein 7-AS (W7-AS). While advanced divertor scenarios relevant for W7-X were already studied in W7-AS, other smaller-scale experiments like Heliotron-J, CHS, and National Compact Stellarator Experiment will be used for the further development of divertor concepts. The two divertor configurations that are being investigated are the helical and the island divertor, as well as the local island divertor, which was successfully demonstrated on CHS and just went into operation on LHD. At present, on its route to a fully closed helical divertor, LHD operates in an open helical divertor configuration. W7-X will be equipped right from the start with an actively cooled discrete island divertor that will allow quasi-continuous operation. The divertor design is very similar to the one explored on W7-AS. For sufficiently large island sizes and not too long field line connection lengths, this divertor gives access to a partially detached quasi-steady-state operating scenario in a newly found high-density H-mode operating regime, which benefits from high energy and low impurity confinement times, with edge radiation levels of up to 90% and sufficient neutral compression in the subdivertor region (>10) for active pumping. The basic physics of the different divertor concepts and associated implementation problems, like asymmetries due to drifts, accessibility of essential operating scenarios, toroidal asymmetries due to symmetry breaking error fields

  14. Employing helicity amplitudes for resummation in SCET

    International Nuclear Information System (INIS)

    Moult, Ian; Stewart, Iain W.; Tackmann, Frank J.; Waalewijn, Wouter J.; Nikhef, Amsterdam

    2016-05-01

    Helicity amplitudes are the fundamental ingredients of many QCD calculations for multi-leg processes. We describe how these can seamlessly be combined with resummation in Soft-Collinear Effective Theory (SCET), by constructing a helicity operator basis for which the Wilson coefficients are directly given in terms of color-ordered helicity amplitudes. This basis is crossing symmetric and has simple transformation properties under discrete symmetries.

  15. Heavy colored SUSY partners from deflected anomaly mediation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Fei [Department of Physics and Engineering, Zhengzhou University,Zhengzhou 450000 (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Academia Sinica,Beijing 100190 (China); Wang, Wenyu [Institute of Theoretical Physics, College of Applied Science, Beijing University of Technology,Beijing 100124 (China); Yang, Jin Min; Zhang, Yang [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Academia Sinica,Beijing 100190 (China)

    2015-07-27

    We propose a deflected anomaly mediation scenario from SUSY QCD which can lead to both positive and negative deflection parameters (there is a smooth transition between these two deflection parameter regions by adjusting certain couplings). Such a scenario can naturally give a SUSY spectrum in which all the colored sparticles are heavy while the sleptons are light. As a result, the discrepancy between the Brookheaven g{sub μ}−2 experiment and LHC data can be reconciled in this scenario. We also find that the parameter space for explaining the g{sub μ}−2 anomaly at 1σ level can be fully covered by the future LUX-ZEPLIN 7.2 Ton experiment.

  16. Deflection of Steel Reinforced Concrete Beam Prestressed With CFRP Bar

    Directory of Open Access Journals (Sweden)

    Selvachandran P.

    2017-09-01

    Full Text Available Carbon Fiber Reinforced polymer (CFRP bars are weak in yielding property which results in sudden failure of structure at failure load. Inclusion of non-pretensioned steel reinforcement in the tension side of CFRP based prestressed concrete beam will balance the yielding requirements of member and it will show the definite crack failure pattern before failure. Experimental investigation has been carried out to study the deflection behavior of partially prestressed beam. Experimental works includes four beam specimens stressed by varying degree of prestressing. The Partial Prestressing Ratio (PPR of specimen is considered for experimental works in the range of 0.6 to 0.8. A new deflection model is recommended in the present study considering the strain contribution of CFRP bar and steel reinforcement for the fully bonded member. New deflection model converges to experimental results with the error of less than 5% .

  17. Force-deflection analysis of offset indentations on pressurised pipes

    International Nuclear Information System (INIS)

    Hyde, T.H.; Luo, R.; Becker, A.A.

    2007-01-01

    The indenter force vs. deflection characteristics of pressurised pipes with long offset indentations under plane strain conditions have been investigated using finite element (FE) and analytical methods with four experimental tests performed on aluminium rings. Two different materials and five different geometries were used to investigate their effects on the elastic-plastic behaviour. A comparison of the experimental, FE and the analytical results indicates that the analytical formulation developed in this paper, for predicting the force-deflection curves for pressurised pipes with offset indenters, is reasonably accurate. Also, all of the analyses presented in this paper indicate that by using a representative flow stress, which is defined as the average of the yield and ultimate tensile stresses, the analytical method can accurately predict the force-deflection curves

  18. Large deflection of viscoelastic beams using fractional derivative model

    International Nuclear Information System (INIS)

    Bahranini, Seyed Masoud Sotoodeh; Eghtesad, Mohammad; Ghavanloo, Esmaeal; Farid, Mehrdad

    2013-01-01

    This paper deals with large deflection of viscoelastic beams using a fractional derivative model. For this purpose, a nonlinear finite element formulation of viscoelastic beams in conjunction with the fractional derivative constitutive equations has been developed. The four-parameter fractional derivative model has been used to describe the constitutive equations. The deflected configuration for a uniform beam with different boundary conditions and loads is presented. The effect of the order of fractional derivative on the large deflection of the cantilever viscoelastic beam, is investigated after 10, 100, and 1000 hours. The main contribution of this paper is finite element implementation for nonlinear analysis of viscoelastic fractional model using the storage of both strain and stress histories. The validity of the present analysis is confirmed by comparing the results with those found in the literature.

  19. Frequency and deflection analysis of cenosphere/glass fiber interply hybrid composite cantilever beam

    Science.gov (United States)

    Bharath, J.; Joladarashi, Sharnappa; Biradar, Srikumar; Kumar, P. Naveen

    2018-04-01

    Interply hybrid laminates contain plies made of two or more different composite systems. Hybrid composites have unique features that can be used to meet specified design requirements in a more cost-effective way than nonhybrid composites. They offer many advantages over conventional composites including balanced strength and stiffness, enhanced bending and membrane mechanical properties, balanced thermal distortion stability, improved fatigue/impact resistance, improved fracture toughness and crack arresting properties, reduced weight and cost. In this paper an interply hybrid laminate composite containing Cenosphere reinforced polymer composite core and glass fiber reinforced polymer composite skin is analysied and effect of volume fraction of filler on frequency and load v/s deflection of hybrid composite are studied. Cenosphere reinforced polymer composite has increased specific strength, specific stiffness, specific density, savings in cost and weight. Glass fiber reinforced polymer composite has higher torsional rigidity when compared to metals. These laminate composites are fabricated to meet several structural applications and hence there is a need to study their vibration and deflection properties. Experimental investigation starts with fabrication of interply hybrid composite with cores of cenosphere reinforced epoxy composite volume fractions of CE 15, CE 25, CE15_UC as per ASTM E756-05C, and glasss fiber reinforced epoxy skin, cast product of required dimension by selecting glass fibre of proper thickness which is currently 0.25mm E-glass bidirectional woven glass fabric having density 2500kg/m3, in standard from cast parts of size 230mmX230mmX5mm in an Aluminum mould. Modal analysis of cantilever beam is performed to study the variation of natural frequency with strain gauge and the commercially available Lab-VIEW software and deflection in each of the cases by optical Laser Displacement Measurement Sensor to perform Load versus Deflection Analysis

  20. Non-intrusive, fast and sensitive ammonia detection by laser photothermal deflection

    International Nuclear Information System (INIS)

    Vries, H.S.M. de; Harren, F.J.M.; Wyers, G.P.; Otjes, R.P.; Slanina, J.; Reuss, J.

    1995-01-01

    A recently developed non-intrusive photothermal deflection (PTD) instrument allows sensitive, rapid and quantitative detection of local ammonia concentrations in the air. Ammonia is vibrationally excited by an infrared CO 2 laser in an intracavity configuration. A HeNe beam passing over the CO 2 laser beam (multipass arrangement) is deflected by the induced refractive index gradient. The detection limit for ammonia in ambient air is 0.5 ppbv with a spatial resolution of a few mm 3 . The time resolution is 0.1 s (single line) or 15 s (multi line). The system is fully automated and suited for non-stop measuring periods of at least one week. Results were compared to those obtained with a continuous-flow denuder (CFD). (author)

  1. Deflection of light and particles by moving gravitational lenses

    International Nuclear Information System (INIS)

    Wucknitz, Olaf; Sperhake, Ulrich

    2004-01-01

    Various authors have investigated the problem of light deflection by radially moving gravitational lenses, but the results presented so far do not appear to agree on the expected deflection angles. Some publications claim a scaling of deflection angles with 1-v to first order in the radial lens velocity v, while others obtained a scaling with 1-2v. In this paper we generalize the calculations for arbitrary lens velocities and show that the first result is the correct one. We discuss the seeming inconsistency of relativistic light deflection with the classical picture of moving test particles by generalizing the lens effect to test particles of arbitrary velocity, including light as a limiting case. We show that the effect of radial motion of the lens is very different for slowly moving test particles and light and that a critical test particle velocity exists for which the motion of the lens has no effect on the deflection angle to first order. An interesting and not immediately intuitive result is obtained in the limit of a highly relativistic motion of the lens towards the observer, where the deflection angle of light reduces to zero. This phenomenon is elucidated in terms of moving refractive media. Furthermore, we discuss the dragging of inertial frames in the field of a moving lens and the corresponding Lense-Thirring precession, in order to shed more light on the geometrical effects in the surroundings of a moving mass. In a second part we discuss the effect of transversal motion on the observed redshift of lensed sources. We demonstrate how a simple kinematic calculation explains the effects for arbitrary velocities of the lens and test particles. Additionally we include the transversal motion of the source and observer to show that all three velocities can be combined into an effective relative transversal velocity similar to the approach used in microlensing studies

  2. Strong deflection lensing by a Lee–Wick black hole

    Directory of Open Access Journals (Sweden)

    Shan-Shan Zhao

    2017-11-01

    Full Text Available We study strong deflection gravitational lensing by a Lee–Wick black hole, which is a non-singular black hole generated by a high derivative modification of Einstein–Hilbert action. The strong deflection lensing is expected to produce a set of relativistic images very closed to the event horizon of the black hole. We estimate its observables for the supermassive black hole in our Galactic center. It is found that the Lee–Wick black hole can be distinguished from the Schwarzschild black hole via such lensing effects when the UV scale is not very large, but the requiring resolution is much higher than current capability.

  3. Multiplexed Force and Deflection Sensing Shell Membranes for Robotic Manipulators

    Science.gov (United States)

    Park, Yong-Lae; Black, Richard; Moslehi, Behzad; Cutkosky, Mark; Chau, Kelvin

    2012-01-01

    Force sensing is an essential requirement for dexterous robot manipulation, e.g., for extravehicular robots making vehicle repairs. Although strain gauges have been widely used, a new sensing approach is desirable for applications that require greater robustness, design flexibility including a high degree of multiplexibility, and immunity to electromagnetic noise. This invention is a force and deflection sensor a flexible shell formed with an elastomer having passageways formed by apertures in the shell, with an optical fiber having one or more Bragg gratings positioned in the passageways for the measurement of force and deflection.

  4. Institute for Fusion Research and Large Helical Device program

    International Nuclear Information System (INIS)

    Iiyoshi, Atsuo

    1989-01-01

    In the research on nuclear fusion, the final objective is to materialize nuclear fusion reactors, and for the purpose, it is necessary to cause nuclear combustion by making the plasma of higher than 100 million deg and confine it for a certain time. So far in various universities, the researches on diversified fusion processes have been advanced, but in February, 1986, the Science Council issued the report 'Nuclear fusion research in universities hereafter'. As the next large scale device, an external conductor system helical device was decided, and it is desirable to found the organization for joint utilization by national universities to promote the project. The researches on the other processes are continued by utilizing the existing facilitie. The reason of selecting a helical device is the data base of the researches carried out so far can be utilized sufficiently, it is sufficiently novel even after 10 years from now, and many researchers can be collected. The place of the research is Toki City, Gifu Prefecture, where the Institute of Plasma Physics, Nagoya University, is to be moved. The basic concept of the superconducting helical device project, the trend of nuclear fusion development in the world, the physical research using a helical system and so on are reported. (Kako, I.)

  5. Orthogonally interdigitated shielded serpentine travelling wave cathode ray tube deflection structure

    Science.gov (United States)

    Hagen, E.C.; Hudson, C.L.

    1995-07-25

    A new deflection structure which deflects a beam of charged particles, such as an electron beam, includes a serpentine set for transmitting a deflection field, and a shielding frame for housing the serpentine set. The serpentine set includes a vertical serpentine deflection element and a horizontal serpentine deflection element. These deflection elements are identical, and are interdigitatedly and orthogonally disposed relative to each other, for forming a central transmission passage, through which the electron beam passes, and is deflected by the deflection field, so as to minimize drift space signal distortion. The shielding frame includes a plurality of ground blocks, and forms an internal serpentine trough within these ground blocks, for housing the serpentine set. The deflection structure further includes a plurality of feedthrough connectors which are inserted through the shielding frame, and which are electrically connected to the serpentine set. 10 figs.

  6. Chaotic coordinates for the Large Helical Device

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, S. R., E-mail: shudson@pppl.gov [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States); Suzuki, Y. [National Institute for Natural Sciences, National Institute for Fusion Sciences, 322-6 Oroshi, Toki, 509-5292 (Japan)

    2014-10-15

    The theory of quadratic-flux-minimizing (QFM) surfaces is reviewed, and numerical techniques that allow high-order QFM surfaces to be efficiently constructed for experimentally relevant, non-integrable magnetic fields are described. As a practical example, the chaotic edge of the magnetic field in the Large Helical Device (LHD) is examined. A precise technique for finding the boundary surface is implemented, the hierarchy of partial barriers associated with the near-critical cantori is constructed, and a coordinate system, which we call chaotic coordinates, that is based on a selection of QFM surfaces is constructed that simplifies the description of the magnetic field, so that flux surfaces become “straight” and islands become “square.”.

  7. Microinstability Studies for the Large Helical Device

    International Nuclear Information System (INIS)

    Rewoldt, G.; Ku, L.-P.; Tang, W.M.; Sugama, H.; Nakajima, N.; Watanabe, K.Y.; Murakami, S.; Yamada, H.; Cooper, W.A.

    2002-01-01

    Fully kinetic assessments of the stability properties of toroidal drift modes have been obtained for cases for the Large Helical Device (LHD). This calculation employs the comprehensive linear microinstability code FULL, as recently extended for nonaxisymmetric systems. The code retains the important effects in the linearized gyrokinetic equation, using the lowest-order ''ballooning representation'' for high toroidal mode number instabilities in the electrostatic limit. These effects include trapped particles, FLR, transit and bounce and magnetic drift frequency resonances, etc., for any number of plasma species. Results for toroidal drift waves destabilized by trapped electrons and ion temperature gradients are presented, using numerically-calculated three-dimensional MHD equilibria. These are reconstructed from experimental measurements. Quasilinear fluxes of particles and energy for each species are also calculated. Pairs of LHD discharges with different magnetic axis positions and with and without pellet injection are compared

  8. Topological helical edge states in water waves over a topographical bottom

    KAUST Repository

    Wu, Shi qiao

    2017-11-27

    We present the discovery of topologically protected helical edge states in water wave systems, which are realized in water wave propagating over a topographical bottom whose height is modulated periodically in a two-dimensional triangular pattern. We develop an effective Hamiltonian to characterize the dispersion relation and use spin Chern numbers to classify the topology. Through full wave simulations we unambiguously demonstrate the robustness of the helical edge states which are immune to defects and disorders so that the backscattering loss is significantly reduced. A spin splitter is designed for water wave systems, where helical edge states with different spin orientations are spatially separated with each other, and potential applications are discussed.

  9. Topological helical edge states in water waves over a topographical bottom

    KAUST Repository

    Wu, Shi qiao; Wu, Ying; Mei, Jun

    2017-01-01

    We present the discovery of topologically protected helical edge states in water wave systems, which are realized in water wave propagating over a topographical bottom whose height is modulated periodically in a two-dimensional triangular pattern. We develop an effective Hamiltonian to characterize the dispersion relation and use spin Chern numbers to classify the topology. Through full wave simulations we unambiguously demonstrate the robustness of the helical edge states which are immune to defects and disorders so that the backscattering loss is significantly reduced. A spin splitter is designed for water wave systems, where helical edge states with different spin orientations are spatially separated with each other, and potential applications are discussed.

  10. On Possibility of Direct Asteroid Deflection by Electric Solar Wind Sail

    Science.gov (United States)

    Merikallio, Sini; Janhunen, Pekka

    2010-05-01

    The Electric Solar Wind Sail (E-sail) is a new propulsion method for interplanetary travel which was invented in 2006 and is currently under development. The E-sail uses charged tethers to extract momentum from the solar wind particles to obtain propulsive thrust. According to current estimates, the E-sail is 2-3 orders of magnitude better than traditional propulsion methods (chemical rockets and ion engines) in terms of produced lifetime-integrated impulse per propulsion system mass. Here we analyze the problem of using the E-sail for directly deflecting an Earth-threatening asteroid. The problem then culminates into how to attach the E-sail device to the asteroid. We assess a number of alternative attachment strategies and arrive at a recommendation of using the gravity tractor method because of its workability for a wide variety of asteroid types. We also consider possible techniques to scale up the E-sail force beyond the baseline one Newton level to deal with more imminent or larger asteroid or cometary threats. As a baseline case we consider a 3 million ton asteroid which can be deflected with a baseline 1 N E-sail in 5-10 years. Once developed, the E-sail would appear to provide a safe and reasonably low-cost way of deflecting dangerous asteroids and other heavenly bodies in cases where the collision threat becomes known several years in advance.

  11. Load-Deflection and Friction Properties of PEEK Wires as Alternative Orthodontic Wires.

    Science.gov (United States)

    Tada, Yoshifumi; Hayakawa, Tohru; Nakamura, Yoshiki

    2017-08-09

    Polyetheretherketone (PEEK) is now attracting attention as an alternative to metal alloys in the dental field. In the present study, we evaluated the load-deflection characteristics of PEEK wires in addition to their frictional properties. Three types of PEEK wires are used: two sizes of rectangular shape, 0.016 × 0.022 in² and 0.019 × 0.025 in² (19-25PEEK), and rounded shape, diameter 0.016 in (16PEEK). As a control, Ni-Ti orthodontic wire, diameter 0.016 in, was used. The three-point bending properties were evaluated in a modified three-point bending system for orthodontics. The static friction between the orthodontic wire and the bracket was also measured. The load-deflection curves were similar among Ni-Ti and PEEK wires, except for 16PEEK with slot-lid ligation. The bending force of 19-25PEEK wire was comparable with that of Ni-Ti wire. 19-25PEEK showed the highest load at the deflection of 1500 μm ( p 0.05). No significant difference was seen in static friction between all three PEEK wires and Ni-Ti wire ( p > 0.05). It is suggested that 19-25PEEK will be applicable for orthodontic treatment with the use of slot-lid ligation.

  12. Evaluation of force released by deflection of orthodontic wires in conventional and self-ligating brackets.

    Science.gov (United States)

    Higa, Rodrigo Hitoshi; Semenara, Nayara Thiago; Henriques, José Fernando Castanha; Janson, Guilherme; Sathler, Renata; Fernandes, Thais Maria Freire

    2016-01-01

    The aim of the study was to evaluate deflection forces of rectangular orthodontic wires in conventional (MorelliTM), active (In-Ovation RTM) and passive (Damon 3MXTM) self-ligating brackets. Two brands of stainless steel and nickel-titanium (NiTi) wires (MorelliTM and GACTM), in addition to OrmcoTM copper-nickel-titanium wires were used. Specimens were assembled in a clinical simulation device especially designed for this study and tested in an Instron universal testing machine. For the testing procedures, an acrylic structure representative of the maxillary right central incisor was lingually moved in activations of 0 to 1 mm, with readings of the force released by deflection in unloading of 0.5, 0.8 and 1 mm at a constant speed of 2 mm/min. Inter-bracket forces with stainless steel, NiTi and CuNiTi were individually compared by two-way ANOVA, followed by Tukey's tests. Results showed that there were lower forces in conventional brackets, followed by active and passive self-ligating brackets. Within the brands, only for NiTi wires, the MorelliTM brand presented higher forces than GACTM wires. Bracket systems provide different degrees of deflection force, with self-ligating brackets showing the highest forces.

  13. Antenna Gain Impact on UWB Wind Turbine Blade Deflection Sensing

    DEFF Research Database (Denmark)

    Zhang, Shuai; Franek, Ondrej; Byskov, Claus

    2018-01-01

    Antenna gain impact on UWB wind turbine blade deflection sensing is studied in this paper. Simulations are applied with a 4.5-meter blade tip. The antennas with high gain (HG) and low gain (LG) in free space are simulated inside a blade. It is interesting to find that tip antennas with HG and LG...

  14. Focused ion beam induced deflections of freestanding thin films

    International Nuclear Information System (INIS)

    Kim, Y.-R.; Chen, P.; Aziz, M. J.; Branton, D.; Vlassak, J. J.

    2006-01-01

    Prominent deflections are shown to occur in freestanding silicon nitride thin membranes when exposed to a 50 keV gallium focused ion beam for ion doses between 10 14 and 10 17 ions/cm 2 . Atomic force microscope topographs were used to quantify elevations on the irradiated side and corresponding depressions of comparable magnitude on the back side, thus indicating that what at first appeared to be protrusions are actually the result of membrane deflections. The shape in high-stress silicon nitride is remarkably flat-topped and differs from that in low-stress silicon nitride. Ion beam induced biaxial compressive stress generation, which is a known deformation mechanism for other amorphous materials at higher ion energies, is hypothesized to be the origin of the deflection. A continuum mechanical model based on this assumption convincingly reproduces the profiles for both low-stress and high-stress membranes and provides a family of unusual shapes that can be created by deflection of freestanding thin films under beam irradiation

  15. Application of the mechanical deflection sensor in blast research

    CSIR Research Space (South Africa)

    Pandelani, T

    2013-10-01

    Full Text Available the occupants. To enable the development of protection solutions for occupants inside military vehicles, the occupant loading must be thoroughly understood. The aim is to show the capability to measure the positive dynamic deflection of the hull plate using...

  16. Correlation function of gravitational deflection angles of light paths

    International Nuclear Information System (INIS)

    Watanabe, Kazuya; Tomita, Kenji.

    1990-04-01

    The correlation function of gravitational deflection angles of light paths is investigated in a simplified cosmological model universe. Under several reasonable assumptions, an analytic formula for the correlation function is derived. The implication to the cosmic microwave background anisotropy and the distance defined by the observed angular (linear) scale of a source is also discussed. (author)

  17. Deflection routing scheme for GMPLS-based OBS networks

    DEFF Research Database (Denmark)

    Eid, Arafat; Mahmood, Waqar; Alomar, Anwar

    2010-01-01

    Integrating the Generalized Multi-Protocol Label Switching (GMPLS) framework into an Optical Burst Switching (OBS) Control Plane is a promising solution to alleviating most of OBS performance and design issues. However, implementing the already proposed OBS deflection routing schemes is not appli...

  18. Deflecting cavity for beam diagnostics at Cornell ERL injector

    International Nuclear Information System (INIS)

    Belomestnykh, Sergey; Bazarov, Ivan; Shemelin, Valery; Sikora, John; Smolenski, Karl; Veshcherevich, Vadim

    2010-01-01

    A single-cell, 1300-MHz, TM110-like mode vertically deflecting cavity is designed and built for beam slice emittance measurements, and to study the temporal response of negative electron affinity photocathodes in the ERL injector at Cornell University. We describe the cavity shape optimization procedure, RF and mechanical design, its performance with beam.

  19. To test photon statistics by atomic beam deflection

    International Nuclear Information System (INIS)

    Wang Yuzhu; Chen Yudan; Huang Weigang; Liu Liang

    1985-02-01

    There exists a simple relation between the photon statistics in resonance fluorescence and the statistics of the momentum transferred to an atom by a plane travelling wave [Cook, R.J., Opt. Commun., 35, 347(1980)]. Using an atomic beam deflection by light pressure, we have observed sub-Poissonian statistics in resonance fluorescence of two-level atoms. (author)

  20. Welding by using doubly-deflected rotating electron beam

    International Nuclear Information System (INIS)

    Dabek, J.W.; Friedel, K.

    1997-01-01

    The paper presents the welding process by using double-deflected rotating electron beam, as a method to obtain good quality welds. It is shown possible variants of work of modified beam, principles of creation, process control and results of welding. Comparison of quality welds obtained by using traditional and modified electron beams is made too. (author). 11 refs, 8 figs

  1. Interferometric weak value deflections: Quantum and classical treatments

    International Nuclear Information System (INIS)

    Howell, John C.; Starling, David J.; Dixon, P. Ben; Vudyasetu, Praveen K.; Jordan, Andrew N.

    2010-01-01

    We derive the weak value deflection given in an article by Dixon et al.[P. B. Dixon et al. Phys. Rev. Lett. 102 173601 (2009)] both quantum mechanically and classically, including diffraction effects. This article is meant to cover some of the mathematical details omitted in that article owing to space constraints.

  2. Beta-helical polymers from isocyanopeptides

    NARCIS (Netherlands)

    Cornelissen, J.J.L.M.; Donners, J.J.J.M.; Gelder, de R.; Graswinckel, W.S.; Metselaar, G.A.; Rowan, A.E.; Sommerdijk, N.A.J.M.; Nolte, R.J.M.

    2001-01-01

    Polymerization of isocyanopeptides results in the formation of high molecular mass polymers that fold in a proteinlike fashion to give helical strands in which the peptide chains are arranged in ß-sheets. The ß-helical polymers retain their structure in water and unfold in a cooperative process at

  3. Magnetic islands created by resonant helical windings

    International Nuclear Information System (INIS)

    Fernandes, A.S.; Heller, M.V.; Caldas, I.L.

    1986-01-01

    The triggering of disruptive instabilities by resonant helical windings in large aspect-ratio tokamaks is associated to destruction of magnetic surfaces. The Chirikov condition is applied to estimate analytically the helical winding current thresholds for ergodization of the magnetic field lines. (Autor) [pt

  4. Helicity amplitudes for matter-coupled gravity

    International Nuclear Information System (INIS)

    Aldrovandi, R.; Novaes, S.F.; Spehler, D.

    1992-07-01

    The Weyl-van der Waerden spinor formalism is applied to the evaluation of helicity invariant amplitudes in the framework of linearized gravitation. The graviton couplings to spin-0, 1 - 2 , 1, and 3 - 2 particles are given, and, to exhibit the reach of this method, the helicity amplitudes for the process electron + positron → photon + graviton are obtained. (author)

  5. Effects of Adaptation on Discrimination of Whisker Deflection Velocity and Angular Direction in a Model of the Barrel Cortex

    Directory of Open Access Journals (Sweden)

    Mainak J. Patel

    2018-06-01

    Full Text Available Two important stimulus features represented within the rodent barrel cortex are velocity and angular direction of whisker deflection. Each cortical barrel receives information from thalamocortical (TC cells that relay information from a single whisker, and TC input is decoded by barrel regular-spiking (RS cells through a feedforward inhibitory architecture (with inhibition delivered by cortical fast-spiking or FS cells. TC cells encode deflection velocity through population synchrony, while deflection direction is encoded through the distribution of spike counts across the TC population. Barrel RS cells encode both deflection direction and velocity with spike rate, and are divided into functional domains by direction preference. Following repetitive whisker stimulation, system adaptation causes a weakening of synaptic inputs to RS cells and diminishes RS cell spike responses, though evidence suggests that stimulus discrimination may improve following adaptation. In this work, I construct a model of the TC, FS, and RS cells comprising a single barrel system—the model incorporates realistic synaptic connectivity and dynamics and simulates both angular direction (through the spatial pattern of TC activation and velocity (through synchrony of the TC population spikes of a deflection of the primary whisker, and I use the model to examine direction and velocity selectivity of barrel RS cells before and after adaptation. I find that velocity and direction selectivity of individual RS cells (measured over multiple trials sharpens following adaptation, but stimulus discrimination using a simple linear classifier by the RS population response during a single trial (a more biologically meaningful measure than single cell discrimination over multiple trials exhibits strikingly different behavior—velocity discrimination is similar both before and after adaptation, while direction classification improves substantially following adaptation. This is the

  6. Improved focusing-and-deflection columns

    International Nuclear Information System (INIS)

    Mui, P.H.; Szilagyi, M.

    1995-01-01

    Our earlier design procedures for constructing quadrupole columns are further expanded to include octupole corrector units and ''octupole'' deflectors with no third-order harmonics. The additional complications are finer partitioning of the plates and increased number of voltage controllers. Two sample designs, one having only the additional octupole deflectors and one having both the deflectors and the correctors, are presented and compared to our previous quadrupole system. The additional octupole components are shown to be capable of increasing the current density from 30% to more than 300% for a four-plate system, designed to focus and scan the electron beam over a circular area of 0.25 mm radius. The electron beam is assumed to have an initial divergence of ±2.3 mrad, an initial energy of 6 kV, a total energy spread of 1 eV, and a final acceleration of 30 keV. These systems are then slightly reoptimized for a superficial comparison with the commercially available column by Micrion Corporation. The numerical results indicate a potential for substantial improvements, demonstrating the power of this design procedure. Finally, a discussion is presented on how the individual components can interact with each other to reduce the various aberrations. copyright 1995 American Vacuum Society

  7. An electromagnetic helical undulator for polarized X-rays

    International Nuclear Information System (INIS)

    Gluskin, E.; Vinokurov, N.; Tcheskidov, V.; Medvedko, A.; Evtushenko, Y.; Kolomogorov, V.; Vobly, P.; Antokhin, E.; Ivanov, P.; Vasserman, I. B.; Trakhtenberg, E. M.; Den Hartog, P. K.; Deriy, B.; Erdmann, M.; Makarov, O.; Moog, E. R.

    1999-01-01

    Linearly and circularly polarized x-rays have been very successfully applied to the study of the properties of materials. Many applications can benefit from the availability of energy-turnable, high-brilliance x-ray beams with adjustable polarization properties. A helical undulator that can generate beams of variable (linear to circular) polarization has been designed and built by the Budker Institute of Nuclear Physics and the Advanced Photon Source. The first harmonic of this 12.8-cm-period device will cover the energy range from 0.4 keV to 3.5 keV. An important feature of this fully electromagnetic device is that it will allow one to generate 100% horizontally (K x =O)or vertically (K y =O) plane-polarized radiation, which will enable many experiments otherwise not technically feasible. With symmetric deflection parameters (K x =K y ), the on-axis radiation will be circularly polarized, with a user-selectable handedness. The polarization can be changed at rates up to 10 Hz

  8. Helical Birods: An Elastic Model of Helically Wound Double-Stranded Rods

    KAUST Repository

    Prior, Christopher

    2014-03-11

    © 2014, Springer Science+Business Media Dordrecht. We consider a geometrically accurate model for a helically wound rope constructed from two intertwined elastic rods. The line of contact has an arbitrary smooth shape which is obtained under the action of an arbitrary set of applied forces and moments. We discuss the general form the theory should take along with an insight into the necessary geometric or constitutive laws which must be detailed in order for the system to be complete. This includes a number of contact laws for the interaction of the two rods, in order to fit various relevant physical scenarios. This discussion also extends to the boundary and how this composite system can be acted upon by a single moment and force pair. A second strand of inquiry concerns the linear response of an initially helical rope to an arbitrary set of forces and moments. In particular we show that if the rope has the dimensions assumed of a rod in the Kirchhoff rod theory then it can be accurately treated as an isotropic inextensible elastic rod. An important consideration in this demonstration is the possible effect of varying the geometric boundary constraints; it is shown the effect of this choice becomes negligible in this limit in which the rope has dimensions similar to those of a Kirchhoff rod. Finally we derive the bending and twisting coefficients of this effective rod.

  9. Impact of helical boundary conditions on nonlinear 3D magnetohydrodynamic simulations of reversed-field pinch

    International Nuclear Information System (INIS)

    Veranda, M; Bonfiglio, D; Cappello, S; Chacón, L; Escande, D F

    2013-01-01

    Helical self-organized reversed-field pinch (RFP) regimes emerge both numerically—in 3D visco-resistive magnetohydrodynamic (MHD) simulations—and experimentally, as in the RFX-mod device at high current (I P above 1 MA). These states, called quasi-single helicity (QSH) states, are characterized by the action of a MHD mode that impresses a quasi-helical symmetry to the system, thus allowing a high degree of magnetic chaos healing. This is in contrast with the multiple helicity (MH) states, where magnetic fluctuations create a chaotic magnetic field degrading the confinement properties of the RFP. This paper reports an extensive numerical study performed in the frame of 3D visco-resistive MHD which considers the effect of helical magnetic boundary conditions, i.e. of a finite value of the radial magnetic field at the edge (magnetic perturbation, MP). We show that the system can be driven to a selected QSH state starting from both spontaneous QSH and MH regimes. In particular, a high enough MP can force a QSH helical self-organization with a helicity different from the spontaneous one. Moreover, MH states can be turned into QSH states with a selected helicity. A threshold in the amplitude of MP is observed above which is able to influence the system. Analysis of the magnetic topology of these simulations indicates that the dominant helical mode is able to temporarily sustain conserved magnetic structures in the core of the plasma. The region occupied by conserved magnetic surfaces increases reducing secondary modes' amplitude to experimental-like values. (paper)

  10. Topology of helical fluid flow

    DEFF Research Database (Denmark)

    Andersen, Morten; Brøns, Morten

    2014-01-01

    function for the topology of the streamline pattern in incompressible flows. On this basis, we perform a comprehensive study of the topology of the flow field generated by a helical vortex filament in an ideal fluid. The classical expression for the stream function obtained by Hardin (Hardin, J. C. 1982...... the zeroes of a single real function of one variable, and we show that three different flow topologies can occur, depending on a single dimensionless parameter. By including the self-induced velocity on the vortex filament by a localised induction approximation, the stream function is slightly modified...... and an extra parameter is introduced. In this setting two new flow topologies arise, but not more than two critical points occur for any combination of parameters....

  11. Helically coiled tube heat exchanger

    International Nuclear Information System (INIS)

    Harris, A.M.

    1981-01-01

    In a heat exchanger such as a steam generator for a nuclear reactor, two or more bundles of helically coiled tubes are arranged in series with the tubes in each bundle integrally continuing through the tube bundles arranged in series therewith. Pitch values for the tubing in any pair of tube bundles, taken transverse to the path of the reactor coolant flow about the tubes, are selected as a ratio of two unequal integers to permit efficient operation of each tube bundle while maintaining the various tube bundles of the heat exchanger within a compact envelope. Preferably, the helix angle and tube pitch parallel to the path of coolant flow are constant for all tubes in a single bundle so that the tubes are of approximately the same length within each bundle

  12. The quantum Hall effect helicity

    Energy Technology Data Exchange (ETDEWEB)

    Shrivastava, Keshav N., E-mail: keshav1001@yahoo.com [Department of Physics, University of Malaya, Kuala Lumpur 50603 (Malaysia); School of Physics, University of Hyderabad, Hyderabad 500046 (India)

    2015-04-16

    The quantum Hall effect in semiconductor heterostructures is explained by two signs in the angular momentum j=l±s and g=(2j+1)/(2l+1) along with the Landau factor (n+1/2). These modifications in the existing theories explain all of the fractional charges. The helicity which is the sign of the product of the linear momentum with the spin p.s plays an important role for the understanding of the data at high magnetic fields. In particular it is found that particles with positive sign in the spin move in one direction and those with negative sign move in another direction which explains the up and down stream motion of the particles.

  13. Helical magnetic axis configuration combined with l = 1 and weak l = -1 torsatron fields

    International Nuclear Information System (INIS)

    Kikuchi, Hitoshi; Saito, Katsunori; Gesso, Hirokazu; Shiina, Shoichi

    1989-01-01

    The superposition of a relatively weak l = -1 torsatron field on a main l = 1 torsatron field leads to the improvement of the confinement properties due to the formation of a local magnetic well, which results from the local curvature of the helical magnetic axis with a larger excursion in the major radius direction. This l±1 helical magnetic axis system has a comparatively simple, compact coil structure. Here the vacuum configuration properties of l = ±1 system are described. (author)

  14. Passive base isolation with superelastic nitinol SMA helical springs

    International Nuclear Information System (INIS)

    Huang, Bin; Zhang, Haiyang; Wang, Han; Song, Gangbing

    2014-01-01

    Seismic isolation of structures such as multi-story buildings, nuclear reactors, bridges, and liquid storage tanks should be designed to preserve structural integrity. By implementing seismic isolation technology, the deformation of superstructures can be dramatically reduced, consequently helping to protect their safety as well. In this paper, an innovative type of passive base isolation system, which is mainly composed of superelastic nitinol SMA helical springs, is developed. In order to verify the effectiveness of the proposed system, a two-story experimental steel frame model is constructed, and two superelastic SMA helical springs are thermo-mechanically built in the laboratory. To describe the nonlinear mechanical properties of the superelastic SMA helical springs under reciprocating load, a phenomenological model is presented in terms of a series of tensile tests. Afterwards, a numerical model of the two-story frame with the suggested isolation system is set up to simulate the response of the isolated frame subjected to an earthquake. Both the experimental and the numerical simulation results indicate that the proposed base isolation system can remarkably suppress structural vibrations and has improved isolation effects when compared with a steel spring isolation system. Due to the capabilities of energy dissipation as well as fully re-centering, it is very applicable to utilize the suggested isolation system in base isolated structures to resist earthquakes. (paper)

  15. Enhanced Control for Local Helicity Injection on the Pegasus ST

    Science.gov (United States)

    Pierren, C.; Bongard, M. W.; Fonck, R. J.; Lewicki, B. T.; Perry, J. M.

    2017-10-01

    Local helicity injection (LHI) experiments on Pegasus rely upon programmable control of a 250 MVA modular power supply system that drives the electromagnets and helicity injection systems. Precise control of the central solenoid is critical to experimental campaigns that test the LHI Taylor relaxation limit and the coupling efficiency of LHI-produced plasmas to Ohmic current drive. Enhancement and expansion of the present control system is underway using field programmable gate array (FPGA) technology for digital logic and control, coupled to new 10 MHz optical-to-digital transceivers for semiconductor level device communication. The system accepts optical command signals from existing analog feedback controllers, transmits them to multiple devices in parallel H-bridges, and aggregates their status signals for fault detection. Present device-level multiplexing/de-multiplexing and protection logic is extended to include bridge-level protections with the FPGA. An input command filter protects against erroneous and/or spurious noise generated commands that could otherwise cause device failures. Fault registration and response times with the FPGA system are 25 ns. Initial system testing indicates an increased immunity to power supply induced noise, enabling plasma operations at higher working capacitor bank voltage. This can increase the applied helicity injection drive voltage, enable longer pulse lengths and improve Ohmic loop voltage control. Work supported by US DOE Grant DE-FG02-96ER54375.

  16. Overview of results from the Large Helical Device

    International Nuclear Information System (INIS)

    Yamada, H.

    2010-11-01

    The physical understanding of net-current free helical plasmas has progressed in the Large Helical Device (LHD) since the last Fusion Energy Conference in Geneva, 2008. The experimental results from LHD have promoted detailed physical documentation of features specific to net-current-free 3-D helical plasmas as well as complementary to the tokamak approach. The primary heating source is NBI with a heating power of 23 MW, and ECH with 3.7 MW plays an important role in local heating and power modulation in transport studies. The maximum central density has reached 1.2 x 10 21 m -3 due to the formation of an Internal Diffusion Barrier (IDB) at the magnetic field of 2.5 T. The IDB has been maintained for 3 s by refueling with repetitive pellet injection. The plasma with a central ion temperature reaching 5.6 keV exhibits the formation of an Internal Transport Barrier (ITB). The ion thermal diffusivity decreases to the level predicted by neoclassical transport. This ITB is accompanied by spontaneous toroidal rotation and an Impurity Hole which generates an impurity-free core. Impurity Hole is due to a large outward convection of impurities in spite of the negative radial electric field. The magnitude of the Impurity Hole is enhanced in the magnetic configuration with larger helical ripple and for higher Z impurities. Another mechanism to suppress impurity contamination has been identified at the plasma edge with a stochastic magnetic field. A helical system shares common physics issues with tokamaks such as 3-D equilibria, transport in a stochastic magnetic field, plasma response to a Resonant Magnetic Perturbation (RMP), divertor physics, and the role of radial electric field and meso-scale structure. (author)

  17. HEMISPHERIC HELICITY TREND FOR SOLAR CYCLE 24

    International Nuclear Information System (INIS)

    Hao Juan; Zhang Mei

    2011-01-01

    Using vector magnetograms obtained with the Spectro-polarimeter (SP) on board Hinode satellite, we studied two helicity parameters (local twist and current helicity) of 64 active regions that occurred in the descending phase of solar cycle 23 and the ascending phase of solar cycle 24. Our analysis gives the following results. (1) The 34 active regions of the solar cycle 24 follow the so-called hemispheric helicity rule, whereas the 30 active regions of the solar cycle 23 do not. (2) When combining all 64 active regions as one sample, they follow the hemispheric helicity sign rule as in most other observations. (3) Despite the so-far most accurate measurement of vector magnetic field given by SP/Hinode, the rule is still weak with large scatters. (4) The data show evidence of different helicity signs between strong and weak fields, confirming previous result from a large sample of ground-based observations. (5) With two example sunspots we show that the helicity parameters change sign from the inner umbra to the outer penumbra, where the sign of penumbra agrees with the sign of the active region as a whole. From these results, we speculate that both the Σ-effect (turbulent convection) and the dynamo have contributed in the generation of helicity, whereas in both cases turbulence in the convection zone has played a significant role.

  18. Comparison of AMI-25 enhanced MRI and helical dynamic CT in the detection of hepatic lesions

    International Nuclear Information System (INIS)

    Saitou, Kazuhiro; Matsuda, Hiromichi; Fukushima, Hiroaki; Kanzaki, Hiroshi; Hirose, Takashi; Karizaki, Dai; Abe, Kimihiko; Amino, Saburou

    1994-01-01

    We performed AMI-25 enhanced MRI and helical dynamic CT in 12 cases of hepatic lesions. Nine of these were hepatocellular carcinomas. Two cases were metastatic liver tumors (the primary lesion was gastric in one and the other was gallbladder cancer). One case was suspected to be adenomatous hyperplasia. Thirty-two lesions were detected in T2-weighted SE images before AMI-25 administration, while 46 lesions were detected in AMI-25 enhanced MRI images. In particular, AMI-25 enhanced MRI was superior to plain MRI in lesions less than 10 mm in size. A total of 48 lesions were detected in helical dynamic CT. Although AMI-25 enhanced MRI almost equaled helical dynamic CT in the detection of liver tumors, helical dynamic CT was slightly superior to AMI-25 enhanced MRI in the detection of subphrenic lesions. It was possible to know the hemodynamics in each hepatic lesion by helical dynamic CT. AMI-25 enhanced MRI was useful to know the inclusion of reticuloendothelial system, and that yielded different diagnoses in adenomatous hyperplasia and well differentiated hepatocellular carcinoma. Helical dynamic CT was useful for qualitative diagnosis. Both AMI-25 enhanced MRI and helical dynamic CT contributed to the detection of liver tumor and qualitative diagnosis. (author)

  19. A data-driven soft sensor for needle deflection in heterogeneous tissue using just-in-time modelling.

    Science.gov (United States)

    Rossa, Carlos; Lehmann, Thomas; Sloboda, Ronald; Usmani, Nawaid; Tavakoli, Mahdi

    2017-08-01

    Global modelling has traditionally been the approach taken to estimate needle deflection in soft tissue. In this paper, we propose a new method based on local data-driven modelling of needle deflection. External measurement of needle-tissue interactions is collected from several insertions in ex vivo tissue to form a cloud of data. Inputs to the system are the needle insertion depth, axial rotations, and the forces and torques measured at the needle base by a force sensor. When a new insertion is performed, the just-in-time learning method estimates the model outputs given the current inputs to the needle-tissue system and the historical database. The query is compared to every observation in the database and is given weights according to some similarity criteria. Only a subset of historical data that is most relevant to the query is selected and a local linear model is fit to the selected points to estimate the query output. The model outputs the 3D deflection of the needle tip and the needle insertion force. The proposed approach is validated in ex vivo multilayered biological tissue in different needle insertion scenarios. Experimental results in five different case studies indicate an accuracy in predicting needle deflection of 0.81 and 1.24 mm in the horizontal and vertical lanes, respectively, and an accuracy of 0.5 N in predicting the needle insertion force over 216 needle insertions.

  20. Polymorphic transformation of helical flagella of bacteria

    Science.gov (United States)

    Lim, Sookkyung; Howard Berg Collaboration; William Ko Collaboration; Yongsam Kim Collaboration; Wanho Lee Collaboration; Charles Peskin Collaboration

    2016-11-01

    Bacteria such as E. coli swim in an aqueous environment by utilizing the rotation of flagellar motors and alternate two modes of motility, runs and tumbles. Runs are steady forward swimming driven by bundles of flagellar filaments whose motors are turning CCW; tumbles involve a reorientation of the direction of swimming triggered by motor reversals. During tumbling, the helical flagellum undergoes polymorphic transformations, which is a local change in helical pitch, helical radius, and handedness. In this work, we investigate the underlying mechanism of structural conformation and how this polymorphic transition plays a role in bacterial swimming. National Science Foundation.

  1. Deflecting modes of the side-coupled cavity structure

    Energy Technology Data Exchange (ETDEWEB)

    Inagaki, Shigemi.

    1990-11-01

    The deflecting modes of the 805 MHz side-coupled cavity structure with the relativistic factor 0.566 are studied. Our main concern is the dispersion properties among different configurations of side-coupling cells and their interpretations. It is shown that the ninety degree side-coupling cell configuration, so to speak, the Mickey Mouse configuration has a merit in reducing the HEM{sub 1} passband. Another concern is the magnitude of the transverse coupling impedance around the synchronization condition. It is shown that the existence of the coupling cell introduces the nonuniformity of the deflecting mode and gives different impedance relative to the beam axis and that the coupling impedance at {pi}/10 exceeds 50 M{Omega}/m if the quality value of the mode is around 12000.

  2. Deflecting modes of the side-coupled cavity structure

    International Nuclear Information System (INIS)

    Inagaki, Shigemi.

    1990-11-01

    The deflecting modes of the 805 MHz side-coupled cavity structure with the relativistic factor 0.566 are studied. Our main concern is the dispersion properties among different configurations of side-coupling cells and their interpretations. It is shown that the ninety degree side-coupling cell configuration, so to speak, the Mickey Mouse configuration has a merit in reducing the HEM 1 passband. Another concern is the magnitude of the transverse coupling impedance around the synchronization condition. It is shown that the existence of the coupling cell introduces the nonuniformity of the deflecting mode and gives different impedance relative to the beam axis and that the coupling impedance at π/10 exceeds 50 MΩ/m if the quality value of the mode is around 12000

  3. Calculating the momentum enhancement factor for asteroid deflection studies

    International Nuclear Information System (INIS)

    Heberling, Tamra; Gisler, Galen; Plesko, Catherine; Weaver, Robert

    2017-01-01

    The possibility of kinetic-impact deflection of threatening near-Earth asteroids will be tested for the first time in the proposed AIDA (Asteroid Impact Deflection Assessment) mission, involving NASAs DART (Double Asteroid Redirection Test). The impact of the DART spacecraft onto the secondary of the binary asteroid 65803 Didymos at a speed of 5 to 7 km/s is expected to alter the mutual orbit by an observable amount. Furthermore, the velocity transferred to the secondary depends largely on the momentum enhancement factor, typically referred to as beta. Here, we use two hydrocodes developed at Los Alamos, RAGE and PAGOSA, to calculate an approximate value for beta in laboratory-scale benchmark experiments. Convergence studies comparing the two codes show the importance of mesh size in estimating this crucial parameter.

  4. Precise atomic mass measurements by deflection mass spectrometry

    CERN Document Server

    Barber, R C

    2003-01-01

    Since its inception nearly 90 years ago by J.J. Thomson, the precise determination of atomic masses by the classical technique of deflecting charged particles in electric and magnetic fields has provided a large body of data on naturally occurring nuclides. Currently, such measurements on stable nuclides have frequently achieved a precision of better than two parts in 10 sup 9 of the mass. A review of the technique, together with a brief summary of the important historical developments in the field of precise atomic mass measurements, will be given. The more recent contributions to this field by the deflection mass spectrometer at the University of Manitoba will be provided as illustrations of the culmination of the techniques used and the applications that have been studied. A brief comparison between this and newer techniques using Penning traps will be presented.

  5. Deflected Mirage Mediation: A Framework for Generalized Supersymmetry Breaking

    International Nuclear Information System (INIS)

    Kim, Ian-Woo

    2008-01-01

    We present a model of supersymmetry breaking in which the contributions from gravity/modulus, anomaly, and gauge mediation are all comparable. We term this scenario 'deflected mirage mediation', which is a generalization of the KKLT-motivated mirage mediation scenario to include gauge mediated contributions. These contributions deflect the gaugino mass unification scale and alter the pattern of soft parameters at low energies. Competitive gauge-mediated terms can naturally appear within phenomenological models based on the KKLT setup by the stabilization of the gauge singlet field responsible for the masses of the messenger fields. We analyze the renormalization group evolution of the supersymmetry breaking terms and the resulting low energy mass spectra.

  6. Strong deflection gravitational lensing by a modified Hayward black hole

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Shan-Shan; Xie, Yi [Nanjing University, School of Astronomy and Space Science, Nanjing (China); Nanjing University, Ministry of Education, Key Laboratory of Modern Astronomy and Astrophysics, Nanjing (China)

    2017-05-15

    A modified Hayward black hole is a nonsingular black hole. It is proposed that it would form when the pressure generated by quantum gravity can stop matter's collapse as the matter reaches the Planck density. Strong deflection gravitational lensing occurring nearby its event horizon might provide some clues of these quantum effects in its central core. We investigate observables of the strong deflection lensing, including angular separations, brightness differences and time delays between its relativistic images, and we estimate their values for the supermassive black hole in the Galactic center. We find that it is possible to distinguish the modified Hayward black hole from a Schwarzschild one, but it demands a very high resolution, beyond current stage. (orig.)

  7. Free Vibration Analysis of Rectangular Orthotropic Membranes in Large Deflection

    Directory of Open Access Journals (Sweden)

    Zheng Zhou-Lian

    2009-01-01

    Full Text Available This paper reviewed the research on the vibration of orthotropic membrane, which commonly applied in the membrane structural engineering. We applied the large deflection theory of membrane to derive the governing vibration equations of orthotropic membrane, solved it, and obtained the power series formula of nonlinear vibration frequency of rectangular membrane with four edges fixed. The paper gave the computational example and compared the two results from the large deflection theory and the small one, respectively. Results obtained from this paper provide some theoretical foundation for the measurement of pretension by frequency method; meanwhile, the results provide some theoretical foundation for the research of nonlinear vibration of membrane structures and the response solving of membrane structures under dynamic loads.

  8. Normal Conducting Deflecting Cavity Development at the Cockcroft Institute

    CERN Document Server

    Burt, G; Dexter, A C; Woolley, B; Jones, R M; Grudiev, A; Dolgashev, V; Wheelhouse, A; Mackenzie, J; McIntosh, P A; Hill, C; Goudket, P; Buckley, S; Lingwood, C

    2013-01-01

    Two normal conducting deflecting structures are currently being developed at the Cockcroft Institute, one as a crab cavity for CERN linear collider CLIC and one for bunch slice diagnostics on low energy electron beams for Electron Beam Test Facility EBTF at Daresbury. Each has its own challenges that need overcome. For CLIC the phase and amplitude tolerances are very stringent and hence beamloading effects and wakefields must be minimised. Significant work has been undertook to understand the effect of the couplers on beamloading and the effect of the couplers on the wakefields. For EBTF the difficulty is avoiding the large beam offset caused by the cavities internal deflecting voltage at the low beam energy. Prototypes for both cavities have been manufactured and results will be presented.

  9. Progress on the gyrocon deflection-modulated amplifier

    International Nuclear Information System (INIS)

    Tallerico, P.J.

    1982-01-01

    The gyrocon is a high-power deflection-modulated amplifier that can have excellent spatial bunching and, hence, high dc-to-rf conversion efficiency. A program to design and build a prototype amplifier at 450 MHz is discussed. Peak powers of 150 kW and conversion efficiencies of 23% have been measured; the testing program is being pursued to improve this performance. Some possible mechanisms for the difference between the experimental and calculated performance are discussed

  10. Plasmoid behavior in helical plasmas

    International Nuclear Information System (INIS)

    Ishizaki, R.; Nakajima, N.

    2009-01-01

    Full text: It is well known that an ablation cloud; a high density and low temperature plasmoid, drifts to the lower field side in tokamak plasmas, which leads to a good performance on fueling in tokamak. Such a good performance, however, has not been obtained yet in the planar axis heliotron; Large Helical Device (LHD) experiments, even if a pellet has been injected from the high field side. The purpose of the study is to clarify the difference on the plasmoid motion between tokamak and LHD plasmas by using the MHD simulation including ablation processes. It is found in tokamaks that the drift motion is induced by a tire tube force and 1/R force in the major radius direction, and that the pressure and density of the plasmoid have oscillation due to fast compressional Alfven wave. On the other hand, the upper and lower portions surrounding the plasmoid center drift to the higher field side, because 1/R force by magnetic field becomes negative in the major radius direction since the magnetic field surrounding the plasmoid is accumulated by the extremely large ablation pressure and the magnetic pressure perturbation becomes positive. It is also found that the plasmoid does not drift when the perturbation of the plasmoid is small. In addition, the motion of the plasmoid is investigated in LHD plasmas in four cases that the plasmoids are initially located at the inner and outer sides of the torus on the vertically and horizontally elongated poloidal cross sections. The plasmoids drift to the lower field sides in all cases. However, in the case that it is located at the inner side of the torus on the horizontally elongated poloidal cross section, it is found that the plasmoid drifts in the negative direction of the major radius and subsequently drifts in the positive direction of it. In other words, the plasmoid finally drifts in the positive direction of the major radius the same as the plasmoid located at the outer side of the torus. This fact might be one of the

  11. Deflection of weakly magnetic materials by superconducting OGMS

    International Nuclear Information System (INIS)

    Boehm, J.; Gerber, R.; Fletcher, D.; Parker, M.R.

    1988-01-01

    Applications of a superconducting Open Gradient Magnetic Separator to fractional separation in air of weakly magnetic materials are presented. The dependence of particle deflection of these materials on the magnetic field strength, release location, magnetic susceptibility, particle density and other properties is investigated. The aim is to maximise the deflection of the magnetically stronger component of the feed to facilitate its separation from the particle stream round the magnet. Materials (e.g. CuSO/sub 4/, MnO/sub 2/) with chi/rho- ratios of the order of 7 x 10/sup -8/ m/sup 3//kg have been deflected. The applicability of dry magnetic separation has thus been considerably extended since up to now the separation of such materials has been restricted to High Gradient Magnetic Separation. The dependence of the separation efficiency upon the method of feeding and the influence of the residence time are studied in order to establish the optimum parameters for the recovery of the desired fraction. The experimental results are compared with predictions of a theory that is based upon novel approximative calculations of magnetic fields in which the use of elliptic integrals is avoided

  12. Angular deflection of rotary nickel titanium files: a comparative study

    Directory of Open Access Journals (Sweden)

    Gianluca Gambarini

    2009-12-01

    Full Text Available A new manufacturing method of twisting nickel titanium wire to produce rotary nickel titanium (RNT files has recently been developed. The aim of the present study was to evaluate whether the new manufacturing process increased the angular deflection of RNT files, by comparing instruments produced using the new manufacturing method (Twisted Files versus instruments produced with the traditional grinding process. Testing was performed on a total of 40 instruments of the following commercially available RNT files: Twisted Files (TF, Profile, K3 and M2 (NRT. All instruments tested had the same dimensions (taper 0.06 and tip size 25. Test procedures strictly followed ISO 3630-1. Data were collected and statistically analyzed by means ANOVA test. The results showed that TF demonstrated significantly higher average angular deflection levels (P<0.05, than RNT manufactured by a grinding process. Since angular deflection represent the amount of rotation (and consequently deformation that a RNT file can withstand before torsional failure, such a significant improvement is a favorable property for the clinical use of the tested RNT files.

  13. Experimental modeling of eddy currents and deflections for tokamak limiters

    International Nuclear Information System (INIS)

    Hua, T.Q.; Knott, M.J.; Turner, L.R.; Wehrle, R.B.

    1986-01-01

    In this study, experiments were performed to investigate deflection, current, and material stress in cantilever beams with the Fusion ELectromagnetic Induction eXperiment (FELIX) at the Argonne National Laboratory. Since structures near the plasma are typically cantilevered, the beams provide a good model for the limiter blades of a tokamak fusion reactor. The test pieces were copper, aluminum, phosphor bronze, and brass cantilever beams, clamped rigidly at one end with a nonconducting support frame inside the FELIX test volume. The primary data recorded as functions of time were the beam deflection measured with a noncontact electro-optical device, the total eddy current measured with a Rogowski coil and linking through a central hole in the beam, and the material stress extracted from strain gauges. Measurements of stress and deflection were taken at selected positions along the beam. The extent of the coupling effect depends on several factors. These include the size, the electrical and mechanical properties of the beam, segmenting of the beam, the decay rate of the dipole field, and the strength of the solenoid field

  14. Moduli stabilization and supersymmetry breaking in deflected mirage mediation

    International Nuclear Information System (INIS)

    Everett, Lisa L.; Kim, Ian-Woo; Ouyang, Peter; Zurek, Kathryn M.

    2008-01-01

    We present a model of supersymmetry breaking in which the contributions from gravity/modulus, anomaly, and gauge mediation are all comparable. We term this scenario 'deflected mirage mediation', which is a generalization of the KKLT-motivated mirage mediation scenario to include gauge mediated contributions. These contributions deflect the gaugino mass unification scale and alter the pattern of soft parameters at low energies. In some cases, this results in a gluino LSP and light stops; in other regions of parameter space, the LSP can be a well-tempered neutralino. We demonstrate explicitly that competitive gauge-mediated terms can naturally appear within phenomenological models based on the KKLT setup by addressing the stabilization of the gauge singlet field which is responsible for the masses of the messenger fields. For viable stabilization mechanisms, the relation between the gauge and anomaly contributions is identical in most cases to that of deflected anomaly mediation, despite the presence of the Kaehler modulus. Turning to TeV scale phenomenology, we analyze the renormalization group evolution of the supersymmetry breaking terms and the resulting low energy mass spectra. The approach sets the stage for studies of such mixed scenarios of supersymmetry breaking at the LHC.

  15. A study of the deflections of metal road guardrail elements

    Directory of Open Access Journals (Sweden)

    O. Prentkovskis

    2009-09-01

    Full Text Available Statistical data on traffic accidents in 2008 in Lithuania is presented. Referring to statistical data, ‘grounding on an obstacle’ makes one-tenth of all registered traffic accidents – 9.4% (an obstacle may be a road guardrail, a lamp post, a tree, a bar, a gate, etc.. Road guardrails of various types are installed on the shoulders and dividing strips of urban and suburban roads. They are as follows: reinforced concrete guardrails, cable guardrails and metal guardrails. Metal guardrails, consisting of Σ-shape metal posts and a protective W-shape horizontal beam, are most popular. The authors of the present paper examine the deformation processes of the elements of the above mentioned guardrail. A mathematical model of metal road guardrail was developed. Metal road guardrail was modelled using one-dimensional first-order finite elements, taking into account only elastic deformations, as well as the effect of soil on the buried post section of the guardrail. Based on the developed mathematical model of metal road guardrail, the deflections of its elements caused by the impact of a vehicle moving at varying speed were determined. The obtained values of deflections of guardrail elements (a protective W-shape horizontal beam and a Σ-shape post presented in paper do not exceed the admissible values (of beam deflections.

  16. Alternating-current ohmic heating in a helical stellarator

    International Nuclear Information System (INIS)

    Funato, Yasuyuki; Kitajima, Sumio; Watanabe, Hiroshige

    1984-01-01

    A toroidal plasma is generated successively by an alternating-current discharge in a helical or non-planar torus, and is confined quasi-stationarily by a longitudinal magnetic field with a high rotational transform angle. The particle confinement time obtained experimentally is estimated to be 3-10 ms, which is compared with theoretical values for this system, and is much larger than the time of pulse interval of the plasma production. (author)

  17. Helicity and Filament Channels? The Straight Twist!

    Science.gov (United States)

    Antiochos, Spiro K.

    2010-01-01

    One of the most important and most puzzling features of the coronal magnetic field is that it appears to have smooth magnetic structure with little evidence for non-potentiality except at special locations, photospheric polarity inversions lines where the non-potentiality is observed as a filament channel. This characteristic feature of the closed-field corona is highly unexpected given that photospheric motions continuously tangle its magnetic field. Although reconnection can eliminate some of the injected structure, it cannot destroy the helicity, which should build up to produce observable complexity. We propose that an inverse cascade process transports the injected helicity from the interior of closed flux regions to their boundaries, polarity inversion lines, creating filament channels. We describe how the helicity is injected and transported and calculate the relevant rates. We argue that one process, helicity transport, can explain both the observed lack and presence of structure in the coronal magnetic field.

  18. Spin versus helicity in processes involving transversity

    CERN Document Server

    Mekhfi, Mustapha

    2011-01-01

    We construct the spin formalism in order to deal in a direct and natural way with processes involving transversity which are now of increasing popularity. The helicity formalism which is more appropriate for collision processes of definite helicity has been so far used also to manage processes with transversity, but at the price of computing numerous helicity amplitudes generally involving unnecessary kinematical variables.In a second step we work out the correspondence between both formalisms and retrieve in another way all results of the helicity formalism but in simpler forms.We then compute certain processes for comparison.A special process:the quark dipole magnetic moment is shown to be exclusively treated within the spin formalism as it is directly related to the transverse spin of the quark inside the baryon.

  19. Helical magnetized wiggler for synchrotron radiation laser

    International Nuclear Information System (INIS)

    Wang Mei; Park, S.Y.; Hirshfield, J.L.

    1999-01-01

    A helical magnetized iron wiggler has been built for a novel infrared synchrotron radiation laser (SRL) experiment. The wiggler consists of four periods of helical iron structure immersed in a solenoid field. This wiggler is to impart transverse velocity to a prebunched 6 MeV electron beam, and thus to obtain a desired high orbit pitch ratio for the SRL. Field tapering at beam entrance is considered and tested on a similar wiggler. Analytic and simulated characteristics of wigglers of this type are discussed and the performance of the fabricated wigglers is demonstrated experimentally. A 4.7 kG peak field was measured for a 6.4 mm air gap and a 5.4 cm wiggler period at a 20 kG solenoid field. The measured helical fields compare favorably with the analytical solution. This type of helical iron wigglers has the potential to be scaled to small periods with strong field amplitude

  20. Helical magnetized wiggler for synchrotron radiation laser

    CERN Document Server

    Wang Mei; Hirshfield, J L

    1999-01-01

    A helical magnetized iron wiggler has been built for a novel infrared synchrotron radiation laser (SRL) experiment. The wiggler consists of four periods of helical iron structure immersed in a solenoid field. This wiggler is to impart transverse velocity to a prebunched 6 MeV electron beam, and thus to obtain a desired high orbit pitch ratio for the SRL. Field tapering at beam entrance is considered and tested on a similar wiggler. Analytic and simulated characteristics of wigglers of this type are discussed and the performance of the fabricated wigglers is demonstrated experimentally. A 4.7 kG peak field was measured for a 6.4 mm air gap and a 5.4 cm wiggler period at a 20 kG solenoid field. The measured helical fields compare favorably with the analytical solution. This type of helical iron wigglers has the potential to be scaled to small periods with strong field amplitude.

  1. Using helical compressors for coke gas condensation

    Energy Technology Data Exchange (ETDEWEB)

    Privalov, V E; Rezunenko, Yu I; Lelyanov, N V; Zarnitzkii, G Eh; Gordienko, A A; Derebenko, I F; Venzhega, A G; Leonov, N P; Gorokhov, N N

    1982-08-01

    Coke oven gas compression is discussed. Presently used multilevel piston compressors are criticized. The paper recommends using helical machines which combine advantages of using volume condensing compressors and compact high-efficiency centrifugal machines. Two kinds of helical compressors are evaluated: dry and oil-filled; their productivities and coke oven gas chemical composition are analyzed. Experiments using helical compressors were undertaken at the Yasinovskii plant. Flowsheet of the installation is shown. Performance results are given in a table. For all operating conditions content of insolubles in oil compounds is found to be lower than the acceptable value (0.08%). Compressor productivity measurements with variable manifold pressure are evaluated. Figures obtained show that efficient condensation of raw coke oven gas is possible. Increasing oil-filled compressor productivity is recommended by decreasing amount of oil injected and simultaneously increasing rotation speed. The dry helical compressor with water seal is found to be most promising for raw coke oven gas condensation. (10 refs.)

  2. Maximum stress estimation model for multi-span waler beams with deflections at the supports using average strains.

    Science.gov (United States)

    Park, Sung Woo; Oh, Byung Kwan; Park, Hyo Seon

    2015-03-30

    The safety of a multi-span waler beam subjected simultaneously to a distributed load and deflections at its supports can be secured by limiting the maximum stress of the beam to a specific value to prevent the beam from reaching a limit state for failure or collapse. Despite the fact that the vast majority of accidents on construction sites occur at waler beams in retaining wall systems, no safety monitoring model that can consider deflections at the supports of the beam is available. In this paper, a maximum stress estimation model for a waler beam based on average strains measured from vibrating wire strain gauges (VWSGs), the most frequently used sensors in construction field, is presented. The model is derived by defining the relationship between the maximum stress and the average strains measured from VWSGs. In addition to the maximum stress, support reactions, deflections at supports, and the magnitudes of distributed loads for the beam structure can be identified by the estimation model using the average strains. Using simulation tests on two multi-span beams, the performance of the model is evaluated by estimating maximum stress, deflections at supports, support reactions, and the magnitudes of distributed loads.

  3. Maximum Stress Estimation Model for Multi-Span Waler Beams with Deflections at the Supports Using Average Strains

    Directory of Open Access Journals (Sweden)

    Sung Woo Park

    2015-03-01

    Full Text Available The safety of a multi-span waler beam subjected simultaneously to a distributed load and deflections at its supports can be secured by limiting the maximum stress of the beam to a specific value to prevent the beam from reaching a limit state for failure or collapse. Despite the fact that the vast majority of accidents on construction sites occur at waler beams in retaining wall systems, no safety monitoring model that can consider deflections at the supports of the beam is available. In this paper, a maximum stress estimation model for a waler beam based on average strains measured from vibrating wire strain gauges (VWSGs, the most frequently used sensors in construction field, is presented. The model is derived by defining the relationship between the maximum stress and the average strains measured from VWSGs. In addition to the maximum stress, support reactions, deflections at supports, and the magnitudes of distributed loads for the beam structure can be identified by the estimation model using the average strains. Using simulation tests on two multi-span beams, the performance of the model is evaluated by estimating maximum stress, deflections at supports, support reactions, and the magnitudes of distributed loads.

  4. Deflections and Strains in Cracked Shafts due to Rotating Loads: A Numerical and Experimental Analysis

    Directory of Open Access Journals (Sweden)

    N. Bachschmid

    2004-01-01

    Full Text Available In this article, the deflections of a circular cross-section beam presenting a transverse crack of different depths, due to different loads (bending, torsion, shear, and axial loads, are analyzed with the aid of a rather refined 3-D model, which takes into account the nonlinear contact forces in the cracked area. The bending and shear loads are applied in several different angular positions, in order to simulate a rotating load on a fixed beam, or, by changing the reference system, a fixed load on a rotating beam. Torsion and axial loads are instead fixed with respect to the beam.

  5. Deflections and Strains in Cracked Shafts Due to Rotating Loads: A Numerical and Experimental Analysis

    Directory of Open Access Journals (Sweden)

    Nicolò Bachschmid

    2003-01-01

    Full Text Available In this article the deflections of a circular cross-section beam presenting a transverse crack of varying depths caused by various loads (bending, torsion, shear, and axial loads are analyzed with the aid of a rather refined three-dimensional model that takes into account the nonlinear contact forces in the cracked area. The bending and shear loads are applied in several different angular positions in order to simulate a rotating load on a fixed beam or, by changing the reference system, a fixed load on a rotating beam. Torsion and axial loads are fixed with respect to the beam.

  6. Multiple helical modes of vortex breakdown

    DEFF Research Database (Denmark)

    Sørensen, Jens Nørkær; Naumov, I. V.; Okulov, Valery

    2011-01-01

    Experimental observations of vortex breakdown in a rotating lid-driven cavity are presented. The results show that vortex breakdown for cavities with high aspect ratios is associated with the appearance of stable helical vortex multiplets. By using results from stability theory generalizing Kelvi......’s problem on vortex polygon stability, and systematically exploring the cavity flow, we succeeded in identifying two new stable vortex breakdown states consisting of triple and quadruple helical multiplets....

  7. Cylindrical Taylor states conserving total absolute magnetic helicity

    Science.gov (United States)

    Low, B. C.; Fang, F.

    2014-09-01

    The Taylor state of a three-dimensional (3D) magnetic field in an upright cylindrical domain V is derived from first principles as an extremum of the total magnetic energy subject to a conserved, total absolute helicity Habs. This new helicity [Low, Phys. Plasmas 18, 052901 (2011)] is distinct from the well known classical total helicity and relative total helicity in common use to describe wholly-contained and anchored fields, respectively. A given field B, tangential along the cylindrical side of V, may be represented as a unique linear superposition of two flux systems, an axially extended system along V and a strictly transverse system carrying information on field-circulation. This specialized Chandrasekhar-Kendall representation defines Habs and permits a neat formulation of the boundary-value problem (BVP) for the Taylor state as a constant-α force-free field, treating 3D wholly-contained and anchored fields on the same conceptual basis. In this formulation, the governing equation is a scalar integro-partial differential equation (PDE). A family of series solutions for an anchored field is presented as an illustration of this class of BVPs. Past treatments of the constant-α field in 3D cylindrical geometry are based on a scalar Helmholtz PDE as the governing equation, with issues of inconsistency in the published field solutions discussed over time in the journal literature. The constant-α force-free equation reduces to a scalar Helmholtz PDE only as special cases of the 3D integro-PDE derived here. In contrast, the constant-α force-free equation and the scalar Helmholtz PDE are absolutely equivalent in the spherical domain as discussed in Appendix. This theoretical study is motivated by the investigation of the Sun's corona but the results are also relevant to laboratory plasmas.

  8. On the helicity of open magnetic fields

    International Nuclear Information System (INIS)

    Prior, C.; Yeates, A. R.

    2014-01-01

    We reconsider the topological interpretation of magnetic helicity for magnetic fields in open domains, and relate this to the relative helicity. Specifically, our domains stretch between two parallel planes, and each of these ends may be magnetically open. It is demonstrated that, while the magnetic helicity is gauge-dependent, its value in any gauge may be physically interpreted as the average winding number among all pairs of field lines with respect to some orthonormal frame field. In fact, the choice of gauge is equivalent to the choice of reference field in the relative helicity, meaning that the magnetic helicity is no less physically meaningful. We prove that a particular gauge always measures the winding with respect to a fixed frame, and propose that this is normally the best choice. For periodic fields, this choice is equivalent to measuring relative helicity with respect to a potential reference field. However, for aperiodic fields, we show that the potential field can be twisted. We prove by construction that there always exists a possible untwisted reference field.

  9. Three-dimensional helical CT for treatment planning of breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hiramatsu, Hideko; Enomoto, Kohji; Ikeda, Tadashi [Keio Univ., Tokyo (Japan). School of Medicine] [and others

    1999-01-01

    The role of three-dimensional (3D) helical CT in the treatment planning of breast cancer was evaluated. Of 36 patients examined, 30 had invasive ductal carcinoma, three had invasive lobular carcinoma, one had DCIS, one had DCIS with minimal invasion, and 1 had Paget`s disease. Patients were examined in the supine position. The whole breast was scanned under about 25 seconds of breath-holding using helical CT (Proceed, Yokogawa Medical Systems, or High-speed Advantage, GE Medical Systems). 3D imaging was obtained with computer assistance (Advantage Windows, GE Medical Systems). Linear and/or spotty enhancement on helical CT was considered to suggest DCIS or intraductal spread in the area surrounding the invasive cancer. Of 36 patients, 24 showed linear and/or spotty enhancement on helical CT, and 22 of those 24 patients had DCIS or intraductal spread. In contrast, 12 of 36 patients were considered to have little or no intraductal spread on helical CT, and eight of the 12 patients had little or no intraductal spread on pathological examination. The sensitivity, specificity, and accuracy rates for detecting intraductal spread on MRI were 85%, 80%, and 83%, respectively. 3D helical CT was considered useful in detecting intraductal spread and planning surgery, however, a larger study using a precise correlation with pathology is necessary. (author)

  10. Diffusion in a tokamak with helical magnetic cells

    International Nuclear Information System (INIS)

    Wakatani, Masahiro

    1975-05-01

    In a tokamak with helical magnetic cells produced by a resonant helical magnetic field, diffusion in the collisional regime is studied. The diffusion coefficient is greatly enhanced near the resonant surface even for a weak helical magnetic field. A theoretical model for disruptive instabilities based on the enhanced transport due to helical magnetic cells is discussed. This may explain experiments of the tokamak with resonant helical fields qualitatively. (author)

  11. Origins of the helical wrapping of phenyleneethynylene polymers about single-walled carbon nanotubes.

    Science.gov (United States)

    Von Bargen, Christopher D; MacDermaid, Christopher M; Lee, One-Sun; Deria, Pravas; Therien, Michael J; Saven, Jeffery G

    2013-10-24

    The highly charged, conjugated polymer poly[p-{2,5-bis(3-propoxysulfonicacidsodiumsalt)}phenylene]ethynylene (PPES) has been shown to wrap single-wall carbon nanotubes (SWNTs), adopting a robust helical superstructure. Surprisingly, PPES adopts a helical rather than a linear conformation when adhered to SWNTs. The complexes formed by PPES and related polymers upon helical wrapping of a SWNT are investigated using atomistic molecular dynamics (MD) simulations in the presence and absence of aqueous solvent. In simulations of the PPES/SWNT system in an aqueous environment, PPES spontaneously takes on a helical conformation. A potential of mean force, ΔA(ξ), is calculated as a function of ξ, the component of the end-to-end vector of the polymer chain projected on the SWNT axis; ξ is a monotonic function of the polymer's helical pitch. ΔA(ξ) provides a means to quantify the relative free energies of helical conformations of the polymer when wrapped about the SWNT. The aqueous system possesses a global minimum in ΔA(ξ) at the experimentally observed value of the helical pitch. The presence of this minimum is associated with preferred side chain conformations, where the side chains adopt conformations that provide van der Waals contact between the tubes and the aliphatic components of the side chains, while exposing the anionic sulfonates for aqueous solvation. The simulations provide a free energy estimate of a 0.2 kcal/mol/monomer preference for the helical over the linear conformation of the PPES/SWNT system in an aqueous environment.

  12. Control of Helical Chirality of Ferrocene-Dipeptide Conjugates by the Secondary Structure of Dipeptide Chains.

    Science.gov (United States)

    Moriuchi, Toshiyuki; Nishiyama, Taiki; Nobu, Masaki; Hirao, Toshikazu

    2017-09-18

    Controlling helical chirality and creating protein secondary structures in cyclic/acyclic ferrocene-dipeptide bioorganometallic conjugates were achieved by adjusting the conformational flexibility of the dipeptide chains. In systems reported to date, the helical chirality of a conjugate was determined by the absolute configuration of the adjacent amino acid reside. In contrast, it was possible to induce both M- and P-helical chirality, even when the configuration of the adjacent amino acid was the same. It is particularly interesting to note that M-helical chirality was produced in a cyclic ferrocene-dipeptide conjugate composed of the l-Ala-d-Pro-cystamine-d-Pro-l-Ala dipeptide sequence (1), in which a type II β-turn-like secondary structure was established. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Helically symmetric experiment, (HSX) goals, design and status

    International Nuclear Information System (INIS)

    Anderson, F.S.B.; Almagri, A.F.; Anderson, D.T.; Matthews, P.G.; Talmadge, J.N.; Shohet, J.L.

    1995-01-01

    HSX is a quasi-helically symmetric (QHS) stellarator currently under construction at the Torsatron-Stellarator Laboratory of the University of Wisconsin-Madison. This device is unique in its magnetic design in that the magnetic field spectrum possesses only a single dominant (helical) component. This design avoids the large direct orbit losses and the low-collisionality neoclassical losses associated with conventional stellarators. The restoration of symmetry to the confining magnetic field makes the neoclassical confinement in this device analogous to an axisymmetric q=1/3 tokamak. The HSX device has been designed with a clear set of primary physics goals: demonstrate the feasibility of construction of a QHS device, examine single particle confinement of injected ions with regard to magnetic field symmetry breaking, compare density and temperature profiles in this helically symmetric system to those for axisymmetric tokamaks and conventional stellarators, examine electric fields and plasma rotation with edge biasing in relation to L-H transitions in symmetric versus non-symmetric stellarator systems, investigate QHS effects on 1/v regime electron confinement, and examine how greatly-reduced neoclassical electron thermal conductivity compares to the experimental χ e profile. 3 refs., 4 figs., 1 tab

  14. Solitary Pulmonary Nodule on Helical Dynamic CT Scans: Analysis of the Enhancement Patterns Using a Computer-Aided Diagnosis (CAD) System

    International Nuclear Information System (INIS)

    Choi, Eun Jung; Jin, Gong Yong; Han, Young Min; Lee, Young Sun; Kweon, Keun Sang

    2008-01-01

    We wanted to investigate the usefulness of a computer-aided diagnosis (CAD) system in assisting radiologists to diagnosis malignant solitary pulmonary nodules (SPNs), as compared with diagnosing SPNs with using direct personal drawing. Forty patients with SPNs were analyzed. After the pre-contrast scan was performed, an additional ten series of post-contrast images were obtained at 20-second intervals. Two investigators measured the attenuation values of the SPNs: a radiologist who drew the regions of interest (ROIs), and a technician who used a CAD system. The Bland and Altman plots were used to compare the net enhancement between a CAD system and direct personal drawing. The diagnostic characteristics of the malignant SPNs were calculated by considering the CAD and direct personal drawing and with using Fisher's exact test. On the Bland and Altman plot, the net enhancement difference between the CAD system and direct personal drawing was not significant (within ± 2 standard deriation). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of diagnosing malignant SPNs using CAD was 92%, 85%, 75%, 96% and 88%, respectively. The sensitivity, specificity, PPV, NPV and accuracy of diagnosing malignant SPNs using direct drawing was 92%, 89%, 79%, 92% and 88%, respectively. The CAD system was a useful tool for diagnosing malignant SPNs

  15. Magnetic helices as metastable states of finite XY ferromagnetic chains: An analytical study

    Science.gov (United States)

    Popov, Alexander P.; Pini, Maria Gloria

    2018-04-01

    We investigated a simple but non trivial model, consisting of a chain of N classical XY spins with nearest neighbor ferromagnetic interaction, where each of the two end-point spins is assumed to be exchange-coupled to a fully-pinned fictitious spin. In the mean field approximation, the system might be representative of a soft ferromagnetic film sandwiched between two magnetically hard layers. We show that, while the ground state is ferromagnetic and collinear, the system can attain non-collinear metastable states in the form of magnetic helices. The helical solutions and their stability were studied analytically in the absence of an external magnetic field. There are four possible classes of solutions. Only one class is metastable, and its helical states contain an integer number of turns. Among the remaining unstable classes, there is a class of helices which contain an integer number of turns. Therefore, an integer number of turns in a helical configuration is a necessary, but not a sufficient, condition for metastability. These results may be useful to devise future applications of metastable magnetic helices as energy-storing elements.

  16. Helical-tokamak hybridization concepts for compact configuration exploration and MHD stabilization

    International Nuclear Information System (INIS)

    Oishi, T.; Yamazaki, K.; Arimoto, H.; Baba, K.; Hasegawa, M.; Ozeki, H.; Shoji, T.; Mikhailov, M.I.

    2010-11-01

    To search for low-aspect-ratio torus systems, a lot of exotic confinement concepts are proposed so far historically. One of the authors previously proposed the tokamak-helical hybrid called TOKASTAR (Tokamak-Stellarator Hybrid) to improve the magnetic local shear near the bad curvature region. This is characterized by simple and compact coil systems with enough divertor space relevant to reactor designs. Based on this TOKASTAR concept, a toroidal mode number N=2 C (compact) -TOKASTAR machine (R - 35 mm) was constructed. The rotational transform of this compact helical configuration is rather small to confine hot ions, but can be utilized as a compact electron plasma machine for multi-purposes. The C-TOKASTAR has a pair of spherically winding helical coils and a pair of poloidal coils. Existence of magnetic surface and electron confinement property in C-TOKASTAR device were investigated by an electron-emission impedance method. Calculation of the particle orbit also supports that closed magnetic surface is formed in the cases that the ratio between poloidal and helical coil current is appropriate. Another aspect of the research using TOKASTAR configuration includes the evaluation of the effect of the outboard helical field application to tokamak plasmas. It is considered that outboard helical field has roles to assist the initiation of plasma current, to improve MHD stability, and so on. To check these roles, we made TOKASTAR-2 machine (R - 0.12 m, B - 1 kG) with ohmic heating central coil, eight toroidal field coils, a pair of vertical field coils and two outboard helical field coil segments. The electron cyclotron heating plasma start-up and plasma current disruption control experiments might be expected in this machine. Calculation of magnetic field line tracing has revealed that magnetic surface can be formed using additional outer helical coils. (author)

  17. SU-E-T-197: Helical Cranial-Spinal Treatments with a Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, J; Bernard, D; Liao, Y; Templeton, A; Turian, J; Chu, J [Rush University Medical Center, Chicago, IL (United States)

    2014-06-01

    Purpose: Craniospinal irradiation (CSI) of systemic disease requires a high level of beam intensity modulation to reduce dose to bone marrow and other critical structures. Current helical delivery machines can take 30 minutes or more of beam-on time to complete these treatments. This pilot study aims to test the feasibility of performing helical treatments with a conventional linear accelerator using longitudinal couch travel during multiple gantry revolutions. Methods: The VMAT optimization package of the Eclipse 10.0 treatment planning system was used to optimize pseudo-helical CSI plans of 5 clinical patient scans. Each gantry revolution was divided into three 120° arcs with each isocenter shifted longitudinally. Treatments requiring more than the maximum 10 arcs used multiple plans with each plan after the first being optimized including the dose of the others (Figure 1). The beam pitch was varied between 0.2 and 0.9 (couch speed 5- 20cm/revolution and field width of 22cm) and dose-volume histograms of critical organs were compared to tomotherapy plans. Results: Viable pseudo-helical plans were achieved using Eclipse. Decreasing the pitch from 0.9 to 0.2 lowered the maximum lens dose by 40%, the mean bone marrow dose by 2.1% and the maximum esophagus dose by 17.5%. (Figure 2). Linac-based helical plans showed dose results comparable to tomotherapy delivery for both target coverage and critical organ sparing, with the D50 of bone marrow and esophagus respectively 12% and 31% lower in the helical linear accelerator plan (Figure 3). Total mean beam-on time for the linear accelerator plan was 8.3 minutes, 54% faster than the tomotherapy average for the same plans. Conclusions: This pilot study has demonstrated the feasibility of planning pseudo-helical treatments for CSI targets using a conventional linac and dynamic couch movement, and supports the ongoing development of true helical optimization and delivery.

  18. Isotope separation by laser deflection of an atomic beam

    International Nuclear Information System (INIS)

    Bernhardt, A.F.

    1975-02-01

    Separation of isotopes of barium was accomplished by laser deflection of a single isotopic component of an atomic beam. With a tunable narrow linewidth dye laser, small differences in absorption frequency of different barium isotopes on the 6s 2 1 S 0 --6s6p 1 P 1 5536A resonance were exploited to deflect atoms of a single isotopic component of an atomic beam through an angle large enough to physically separate them from the atomic beam. It is shown that the principal limitation on separation efficiency, the fraction of the desired isotopic component which can be separated, is determined by the branching ratio from the excited state into metastable states. The isotopic purity of the separated atoms was measured to be in excess of 0.9, limited only by instrumental uncertainty. To improve the efficiency of separation, a second dye laser was employed to excite atoms which had decayed to the 6s5d metastable state into the 6p5d 1 P 1 state from which they could decay to the ground state and continue to be deflected on the 5535A transition. With the addition of the second laser, separation efficiency of greater than 83 percent was achieved, limited by metastable state accumulation in the 5d 2 1 D 2 state which is accessible from the 6p5d 1 P 1 level. It was found that the decay rate from the 6p5d state into the 5d 2 metastable state was fully 2/3 the decay rate to the ground state, corresponding to an oscillator strength of 0.58. (U.S.)

  19. Computational analysis of the effect of surface roughness on the deflection of gold coated silicon micro-cantilevers due to molecular adsorption

    Science.gov (United States)

    Hayden, Victor

    In this work numerical simulations were performed in order to study the effects of surface roughness on the deflection of gold coated silicon cantilevers due to molecular adsorption. The cantilever was modeled using a ball and spring system where the spring constants for the Si-Si, Si-Au, and Au-Au bonds were obtained from first principal calculations. The molecular adsorption process was simulated by elongating the natural bond length at available bonding sites chosen randomly on the cantilever. Increasing the bond length created a surface stress on the cantilever causing it to deflect. In all cases the structure refinement was performed by minimizing the energy of the system using a simulated annealing algorithm and a high quality random number generator called Mersenne Twister. The system studied consisted of a 1 micrometer by 1 micrometer portion of a cantilever of various surface roughnesses with variable boundary condition and was processed in parallel on the ACEnet (Atlantic Computational Excellence Network) cluster. The results have indicated that cantilevers with a rougher gold surface deflected more than those with a smoother surface. The increase in deflection is attributed to an increase in stress raisers in the gold film localized around the surface features. The onset of stress raisers increases the differential stress between the top and bottom surfaces and results in an increase in the deflection of the cantilever.

  20. Deflected Mirage Mediation: A Phenomenological Framework for Generalized Supersymmetry Breaking

    International Nuclear Information System (INIS)

    Everett, Lisa L.; Kim, Ian-Woo; Ouyang, Peter; Zurek, Kathryn M.

    2008-01-01

    We present a general phenomenological framework for dialing between gravity mediation, gauge mediation, and anomaly mediation. The approach is motivated from recent developments in moduli stabilization, which suggest that gravity mediated terms can be effectively loop suppressed and thus comparable to gauge and anomaly mediated terms. The gauginos exhibit a mirage unification behavior at a ''deflected'' scale, and gluinos are often the lightest colored sparticles. The approach provides a rich setting in which to explore generalized supersymmetry breaking at the CERN Large Hadron Collider

  1. Angular dispersion and deflection function for heavy ion elastic scattering

    International Nuclear Information System (INIS)

    Bai Zhen; Han Jianlong; Hu Zhengguo; Chinese Academy of Sciences, Beijing

    2007-01-01

    The differential cross sections for elastic scattering products of 17 F on 208 Pb have been measured. The angular dispersion plots of ln(dσ/dθ) versus θ 2 are obtained from the angular distribution of the elastic scattering differential cross sections. Systematical analysis on the angular dispersion for the available experimental data indicates that there is an angular dispersion turning angle at forward angular range within the grazing angle. This turning angle can be clarified as nuclear rainbow in classical deflection function. The exotic behaviour of the nuclear rainbow angle offers a new probe to investigate the halo and skin phenomena. (authors)

  2. Calculation of deflection for cross laminated timber floor panel

    Directory of Open Access Journals (Sweden)

    Kozarić Ljiljana M.

    2016-01-01

    Full Text Available In this paper analytically calculated values of effective flexural stiffness and deflections of five-layer CLT panels height 14 cm due to the payload defined in Eurocode 1 for floors in residential buildings are compared. Effective flexural stiffness was calculated using Gamma method, K-method and Kreuzinger's analogy. Three floor panels with identical height but with different combinations of lamination thicknesses in cross-layers were analyzed. The panels are 4.5 meters long and 1 meter wide. Lamination thicknesses in cross-sections of panels are 33,4 cm+21,9 cm, then 33 cm+22,5 cm and 52,8 cm.

  3. Transit time spreads in biased paracentric hemispherical deflection analyzers

    International Nuclear Information System (INIS)

    Sise, Omer; Zouros, Theo J.M.

    2016-01-01

    The biased paracentric hemispherical deflection analyzers (HDAs) are an alternative to conventional (centric) HDAs maintaining greater dispersion, lower angular aberrations, and hence better energy resolution without the use of any additional fringing field correctors. In the present work, the transit time spread of the biased paracentric HDA is computed over a wide range of analyzer parameters. The combination of high energy resolution with good time resolution and simplicity of design makes the biased paracentric analyzers very promising for both coincidence and singles spectroscopy applications.

  4. Transit time spreads in biased paracentric hemispherical deflection analyzers

    Energy Technology Data Exchange (ETDEWEB)

    Sise, Omer, E-mail: omersise@sdu.edu.tr [Dept. of Science Education, Faculty of Education, Suleyman Demirel Univ., 32260 Isparta (Turkey); Zouros, Theo J.M. [Dept. of Physics, Univ. of Crete, P.O. Box 2208, GR 71003 Heraklion (Greece); Tandem Lab, INPP, NCSR Demokritos, P.O. Box 60228, GR 15310 Ag. Paraskevi (Greece)

    2016-02-15

    The biased paracentric hemispherical deflection analyzers (HDAs) are an alternative to conventional (centric) HDAs maintaining greater dispersion, lower angular aberrations, and hence better energy resolution without the use of any additional fringing field correctors. In the present work, the transit time spread of the biased paracentric HDA is computed over a wide range of analyzer parameters. The combination of high energy resolution with good time resolution and simplicity of design makes the biased paracentric analyzers very promising for both coincidence and singles spectroscopy applications.

  5. Transit time spreads in biased paracentric hemispherical deflection analyzers

    Science.gov (United States)

    Sise, Omer; Zouros, Theo J. M.

    2016-02-01

    The biased paracentric hemispherical deflection analyzers (HDAs) are an alternative to conventional (centric) HDAs maintaining greater dispersion, lower angular aberrations, and hence better energy resolution without the use of any additional fringing field correctors. In the present work, the transit time spread of the biased paracentric HDA is computed over a wide range of analyzer parameters. The combination of high energy resolution with good time resolution and simplicity of design makes the biased paracentric analyzers very promising for both coincidence and singles spectroscopy applications.

  6. Gyrocon: a deflection-modulated, high-power microwave amplifier

    International Nuclear Information System (INIS)

    Tallerico, P.J.

    1977-10-01

    A large-signal, relativistic theory of the electron-field interaction in a new class of microwave amplifiers is presented and applied to the analysis of a high-power, 450-MHz amplifier for accelerator applications. The analysis indicates that electronic efficiencies in excess of 90 percent are obtainable and that overall efficiencies of 90 percent are possible. The amplifier is unique in several respects; the electron velocity is perpendicular to the circuit energy flow, the device uses a fast-wave circuit, and the electron beam is deflection modulated

  7. From plasma crystals and helical structures towards inorganic living matter

    International Nuclear Information System (INIS)

    Tsytovich, V N; Morfill, G E; Fortov, V E; Gusein-Zade, N G; Klumov, B A; Vladimirov, S V

    2007-01-01

    Complex plasmas may naturally self-organize themselves into stable interacting helical structures that exhibit features normally attributed to organic living matter. The self-organization is based on non-trivial physical mechanisms of plasma interactions involving over-screening of plasma polarization. As a result, each helical string composed of solid microparticles is topologically and dynamically controlled by plasma fluxes leading to particle charging and over-screening, the latter providing attraction even among helical strings of the same charge sign. These interacting complex structures exhibit thermodynamic and evolutionary features thought to be peculiar only to living matter such as bifurcations that serve as 'memory marks', self-duplication, metabolic rates in a thermodynamically open system, and non-Hamiltonian dynamics. We examine the salient features of this new complex 'state of soft matter' in light of the autonomy, evolution, progenity and autopoiesis principles used to define life. It is concluded that complex self-organized plasma structures exhibit all the necessary properties to qualify them as candidates for inorganic living matter that may exist in space provided certain conditions allow them to evolve naturally

  8. A Novel Laser and Video-Based Displacement Transducer to Monitor Bridge Deflections.

    Science.gov (United States)

    Vicente, Miguel A; Gonzalez, Dorys C; Minguez, Jesus; Schumacher, Thomas

    2018-03-25

    The measurement of static vertical deflections on bridges continues to be a first-level technological challenge. These data are of great interest, especially for the case of long-term bridge monitoring; in fact, they are perhaps more valuable than any other measurable parameter. This is because material degradation processes and changes of the mechanical properties of the structure due to aging (for example creep and shrinkage in concrete bridges) have a direct impact on the exhibited static vertical deflections. This paper introduces and evaluates an approach to monitor displacements and rotations of structures using a novel laser and video-based displacement transducer (LVBDT). The proposed system combines the use of laser beams, LED lights, and a digital video camera, and was especially designed to capture static and slow-varying displacements. Contrary to other video-based approaches, the camera is located on the bridge, hence allowing to capture displacements at one location. Subsequently, the sensing approach and the procedure to estimate displacements and the rotations are described. Additionally, laboratory and in-service field testing carried out to validate the system are presented and discussed. The results demonstrate that the proposed sensing approach is robust, accurate, and reliable, and also inexpensive, which are essential for field implementation.

  9. Effects of varying the through silicon via liners thickness on their hoop stresses and deflections

    Directory of Open Access Journals (Sweden)

    Juma Mary Atieno

    2017-03-01

    Full Text Available Through silicon via (TSV interconnect reliability is a problem in electronic packaging. The authors address the insertion losses, deflections which can result to separation of TSV layers and hoop stresses. These problems are due to different coefficient of thermal expansion between materials. The authors propose a robust methodology for (TSV liners in this paper which in turn solves the reliability problem in (TSV. Silicon dioxide material is used in their paper as a TSV liner. First, they modelled the equivalent TSV circuit in advanced design systems (ADS. The authors then simulated it to obtain the TSV characterisation from which they obtained the S-parameter S21 which represents the insertion losses. Insertion losses have been described with changes in frequencies from 0 to 20 GHz with changes in TSV thickness from 7 to 8 µm. Later two different shapes of the TSV liner; the disc- and rod-shaped are modelled in analysis system 14 software. The two shapes with a radius of 5 µm each and a fixed pressure of 100 µPa developed changes in hoop stresses and deflections when the liners thicknesses are varied from 2 to 3 µm. The disc shape experienced least reliability problems so the authors propose its use in via structures.

  10. Measurement of ultra-low ion energy of decelerated ion beam using a deflecting electric field

    Energy Technology Data Exchange (ETDEWEB)

    Thopan, P.; Suwannakachorn, D.; Tippawan, U. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@thep-center.org [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2015-12-15

    In investigation on ultra-low-energy ion bombardment effect on DNA, an ion beam deceleration lens was developed for high-quality ultra-low-energy ion beam. Measurement of the ion energy after deceleration was necessary to confirm the ion beam really decelerated as theoretically predicted. In contrast to conventional methods, this work used a simple deflecting electrostatic field after the deceleration lens to bend the ion beam. The beam bending distance depended on the ion energy and was described and simulated. A system for the measurement of the ion beam energy was constructed. It consisted of a pair of parallel electrode plates to generate the deflecting electrical field, a copper rod measurement piece to detect ion beam current, a vernier caliper to mark the beam position, a stepping motor to translate the measurement rod, and a webcam-camera to read the beam bending distance. The entire system was installed after the ion-beam deceleration lens inside the large chamber of the bioengineering vertical ion beam line. Moving the measurement rod across the decelerated ion beam enabled to obtain beam profiles, from which the beam bending distance could be known and the ion beam energy could be calculated. The measurement results were in good agreement with theoretical and simulated results.

  11. Dynamic helical CT mammography of breast cancer

    International Nuclear Information System (INIS)

    Yamamoto, Akira; Fukushima, Hitoshi; Okamura, Ryuji; Nakamura, Yoshiaki; Morimoto, Taisuke; Urata, Yoji; Mukaihara, Sumio; Hayakawa, Katsumi

    2006-01-01

    The purpose of this study was to determine whether dynamic helical computed tomography (CT)-mammography could assist in selecting the most appropriate surgical method in women with breast cancer. Preoperative contrast-enhanced helical CT scanning of the breast was performed on 133 female patients with suspicion of breast cancer at the same time as clinical, mammographic, and/or ultrasonographic examinations. The patients were scanned in the prone position with a specially designed CT-compatible device. A helical scan was made with rapid intravenous bolus injection (3 ml/s) of 100 ml of iodine contrast material. Three-dimensional maximum intensity projection (MIP) images were reconstructed, and CT findings were correlated with surgical and histopathological findings. Histopathological analysis revealed 84 malignant lesions and seven benign lesions. The sensitivity, specificity, and accuracy levels of the CT scanning were 94.6%, 58.6%, and 78.9%. Helical scanning alone revealed additional contralateral carcinomas in three of four patients and additional ipsilateral carcinomas in three of five patients. However, the technique gave false-positive readings in 24 patients. The preoperative CT-mammogram altered the surgical method in six patients. Dynamic helical CT-mammography in the prone position may be one of the choices of adjunct imaging in patients with suspected breast cancer scheduled for surgery. (author)

  12. Introduction to the m = 1 helicity source

    International Nuclear Information System (INIS)

    Platts, D.A.; Jarboe, T.R.; Wright, B.L.

    1985-01-01

    The m = 1 Helicity Source, formerly called the Kinked Z-pinch, was developed as part of the Electrode Studies program at Los Alamos. The Electrode Studies program was initiated to study the control of electrode erosion in long discharge duration spheromak sources. Erosion control is necessary to reduce plasma impurities and to obtain adequate electrode lifetimes. The first task of the Electrode Studies program is to determine, from among a variety of configurations including the coaxial one, a helicity source geometry with good prospects for erosion control. The more efficient the helicity source the easier it will be to control erosion, but the source most also be easy to diagnose and modify if it is to be a useful test bed. The various erosion control techniques which have been proposed will require extensive experimentation to evaluate and optimize. Proposed techniques include, using refractory metals, profiling of the electrodes and magnetic fields, and various gas injection schemes including porous electrodes. It is considered necessary to do these experiments on an optimized helicity source so that the electrode geometries and plasma properties will be relevant. Therefore the present Electrode Studies program is aimed at developing an improved helicity source design

  13. Self-assembly of hard helices: a rich and unconventional polymorphism.

    Science.gov (United States)

    Kolli, Hima Bindu; Frezza, Elisa; Cinacchi, Giorgio; Ferrarini, Alberta; Giacometti, Achille; Hudson, Toby S; De Michele, Cristiano; Sciortino, Francesco

    2014-11-07

    Hard helices can be regarded as a paradigmatic elementary model for a number of natural and synthetic soft matter systems, all featuring the helix as their basic structural unit, from natural polynucleotides and polypeptides to synthetic helical polymers, and from bacterial flagella to colloidal helices. Here we present an extensive investigation of the phase diagram of hard helices using a variety of methods. Isobaric Monte Carlo numerical simulations are used to trace the phase diagram; on going from the low-density isotropic to the high-density compact phases a rich polymorphism is observed, exhibiting a special chiral screw-like nematic phase and a number of chiral and/or polar smectic phases. We present full characterization of the latter, showing that they have unconventional features, ascribable to the helical shape of the constituent particles. Equal area construction is used to locate the isotropic-to-nematic phase transition, and the results are compared with those stemming from an Onsager-like theory. Density functional theory is also used to study the nematic-to-screw-nematic phase transition; within the simplifying assumption of perfectly parallel helices, we compare different levels of approximation, that is second- and third-virial expansions and a Parsons-Lee correction.

  14. Effect of self-deflection on a totally asymmetric simple exclusion process with functions of site assignments

    Science.gov (United States)

    Tsuzuki, Satori; Yanagisawa, Daichi; Nishinari, Katsuhiro

    2018-04-01

    This study proposes a model of a totally asymmetric simple exclusion process on a single-channel lane with functions of site assignments along the pit lane. The system model attempts to insert a new particle to the leftmost site at a certain probability by randomly selecting one of the empty sites in the pit lane, and reserving it for the particle. Thereafter, the particle is directed to stop at the site only once during its travel. Recently, the system was determined to show a self-deflection effect, in which the site usage distribution biases spontaneously toward the leftmost site, and the throughput becomes maximum when the site usage distribution is slightly biased to the rightmost site. Our exact analysis describes this deflection effect and show a good agreement with simulations.

  15. Hydrogen recycling and transport in the helical divertor of TEXTOR

    Energy Technology Data Exchange (ETDEWEB)

    Clever, Meike

    2010-07-01

    The aim of this thesis was to investigate the hydrogen recycling at the target plates of the helical divertor in TEXTOR and by this the capability of this divertor configuration to access such favourable operational regimes. In order to study the different divertor density regimes in TEXTOR, discharges were performed in which the total plasma density was increased continuously up to the density limit. The recycling was investigated in a fixed helical divertor structure where four helical strike points with a poloidal width of about 8-10 cm are created at the divertor target plates. The experimental investigation of the hydrogen recycling was carried out using mainly spectroscopic methods supplemented by Langmuir probe, interferometric and atomic beam measurements. In the framework of this thesis a spectroscopic multi camera system has been built that facilitates the simultaneous observation of four different spectral lines, recording images of the divertor target plates and the plasma volume close to the target. The system facilitates the simultaneous measurement of the poloidal and toroidal pattern of the recycling flux at the divertor target without the need for sweeping the plasma structure. The simultaneous observation of different spectral lines reduces the uncertainty in the analysis based on several lines, as the contribution from uncertainties in the reproducibility of plasma parameters in different discharges are eliminated and only the uncertainty of the measurement method limits the accuracy. The spatial resolution of the system in poloidal and toroidal direction (0.8 mm{+-}0.01 mm) is small compared to the separation of the helical strike points, the capability of the measurement method to resolve these structures is therefore limited by the line-of-sight integration and the penetration depth of the light emitting species. The measurements showed that the recycling flux increases linearly with increasing plasma density, a high recycling regime is not

  16. Hydrogen recycling and transport in the helical divertor of TEXTOR

    International Nuclear Information System (INIS)

    Clever, Meike

    2010-01-01

    The aim of this thesis was to investigate the hydrogen recycling at the target plates of the helical divertor in TEXTOR and by this the capability of this divertor configuration to access such favourable operational regimes. In order to study the different divertor density regimes in TEXTOR, discharges were performed in which the total plasma density was increased continuously up to the density limit. The recycling was investigated in a fixed helical divertor structure where four helical strike points with a poloidal width of about 8-10 cm are created at the divertor target plates. The experimental investigation of the hydrogen recycling was carried out using mainly spectroscopic methods supplemented by Langmuir probe, interferometric and atomic beam measurements. In the framework of this thesis a spectroscopic multi camera system has been built that facilitates the simultaneous observation of four different spectral lines, recording images of the divertor target plates and the plasma volume close to the target. The system facilitates the simultaneous measurement of the poloidal and toroidal pattern of the recycling flux at the divertor target without the need for sweeping the plasma structure. The simultaneous observation of different spectral lines reduces the uncertainty in the analysis based on several lines, as the contribution from uncertainties in the reproducibility of plasma parameters in different discharges are eliminated and only the uncertainty of the measurement method limits the accuracy. The spatial resolution of the system in poloidal and toroidal direction (0.8 mm±0.01 mm) is small compared to the separation of the helical strike points, the capability of the measurement method to resolve these structures is therefore limited by the line-of-sight integration and the penetration depth of the light emitting species. The measurements showed that the recycling flux increases linearly with increasing plasma density, a high recycling regime is not

  17. SECONDARY POPULATION OF INTERSTELLAR NEUTRALS seems deflected to the side

    Science.gov (United States)

    Nakagawa, H.; Bzowski, M.; Yamazaki, A.; Fukunishi, H.; Watanabe, S.; Takahashi, Y.; Taguchi, M.

    Recently the neutral hydrogen flow in the inner heliosphere was found to be deflected relative to the helium flow by about 4 degrees Lallement et al 2005 The explanation of this delfection offered was a distortion of the heliosphere under the action of an ambient interstellar magnetic field In a separate study a number of data sets pertaining to interstellar neutral atoms obtained with various techniques were compiled and interpreted as due to an inflow of interstellar gas from an ecliptic longitude shifted by 10 - 40 degrees from the canonical upstream interstellar neutral flow direction at 254 degrees Collier et al 2004 The origin and properties of such a flow is still under debate We have performed a cross-experiment analysis of the heliospheric hydrogen and helium photometric observations performed simltaneously by the Nozomi spacecraft between the Earth and Mars orbit and explored possible deflection of hydrogen and helium flows with respect to the canonical upwind direction For the interpretation we used predictions of a state of the art 3D and fully time-dependent model of the neutral gas in the heliosphere with the boundary conditions ionization rates and radiation pressure taken from literature The model includes two populations of the thermal interstellar hydrogen predicted by the highly-reputed Moscow Monte Carlo model of the heliosphere The agreement between the data and simulations is not satifactory when one assumes that the upwind direction is the same for both populations and identical with the direction derived from inerstellar helium

  18. Exploration of Piezoelectric Bimorph Deflection in Synthetic Jet Actuators

    Science.gov (United States)

    Housley, Kevin; Amitay, Michael

    2017-11-01

    The design of piezoelectric bimorphs for synthetic jet actuators could be improved by greater understanding of the deflection of the bimorphs; both their mode shapes and the resulting volume change inside the actuator. The velocity performance of synthetic jet actuators is dependent on this volume change and the associated internal pressure changes. Knowledge of these could aid in refining the geometry of the cavity to improve efficiency. Phase-locked jet velocities and maps of displacement of the surface of the bimorph were compared between actuators of varying diameter. Results from a bimorph of alternate stiffness were also compared. Bimorphs with higher stiffness exhibited a more desirable (0,1) mode shape, which produced a high volume change inside of the actuator cavity. Those with lower stiffness allowed for greater displacement of the surface, initially increasing the volume change, but exhibited higher mode shapes at certain frequency ranges. These higher node shapes sharply reduced the volume change and negatively impacted the velocity of the jet at those frequencies. Adjustments to the distribution of stiffness along the radius of the bimorph could prevent this and allow for improved deflection without the risk of reaching higher modes.

  19. Effects of large bending deflections on blade flutter limits

    Energy Technology Data Exchange (ETDEWEB)

    Kallesoee, Bjarne Skovmose; Hartvig Hansen, Morten

    2008-04-15

    The coupling of bending and torsion due to large blade bending are assumed to have some effects of the flutter limits of wind turbines. In the present report, the aeroelastic blade model suggested by Kallesoee, which is similar to a second order model, is used to investigate the aeroelastic stability limits of the RWT blade with and without the effects of the large blade deflection. The investigation shows no significant change of the flutter limit on the rotor speed due to the blade deflection,whereas the first edgewise bending mode becomes negatively damped due to the coupling with blade torsion which causes a change of the effective direction of blade vibration. These observations are confirmed by nonlinear aeroelastic simulations using HAWC2. This work is part of the UpWind project funded by the European Commission under the contract number SES6-CT-2005-019945 which is gratefully acknowledged. This report is the deliverable D2.3 of the UpWind project. (au)

  20. Clinical application of helical CT colonography

    International Nuclear Information System (INIS)

    Zeng Huiliang; Zhu Xinjin; Liang Rujian; Liang Jianhao; Ou Weiqian; Wen Haomao

    2009-01-01

    Objective: To investigate the clinical value of 16-slice helical CT colonography in the diagnosis of colon tumor and polypus. Methods: 16-slice helical CT volumetric scanning was performed in 18 patients with colonic disease, including colonic tumor (n=16) and colonic polypus (n=2). 3D images, virtual endoscopy and multiplanar reformation were obtained in the AW4.1 workstation. CT appearances were compared with operation and fiberoptic colonoscopy. Results: Satisfied results were achieved from 18 patients, no difference found in results between CT colonography and operation in 16 patients with colonic tumor. Conclusion: 16-slice helical CT colonography is of great value in preoperative staging of colonic tumor and have a high value in clinical application. (authors)

  1. Helicity antenna showers for hadron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Nadine; Skands, Peter [Monash University, School of Physics and Astronomy, Clayton, VIC (Australia); Lifson, Andrew [Monash University, School of Physics and Astronomy, Clayton, VIC (Australia); ETH Zuerich, Zurich (Switzerland)

    2017-10-15

    We present a complete set of helicity-dependent 2 → 3 antenna functions for QCD initial- and final-state radiation. The functions are implemented in the Vincia shower Monte Carlo framework and are used to generate showers for hadron-collider processes in which helicities are explicitly sampled (and conserved) at each step of the evolution. Although not capturing the full effects of spin correlations, the explicit helicity sampling does permit a significantly faster evaluation of fixed-order matrix-element corrections. A further speed increase is achieved via the implementation of a new fast library of analytical MHV amplitudes, while matrix elements from Madgraph are used for non-MHV configurations. A few examples of applications to QCD 2 → 2 processes are given, comparing the newly released Vincia 2.200 to Pythia 8.226. (orig.)

  2. Manipulation of wavefront using helical metamaterials.

    Science.gov (United States)

    Yang, Zhenyu; Wang, Zhaokun; Tao, Huan; Zhao, Ming

    2016-08-08

    Helical metamaterials, a kind of 3-dimensional structure, has relatively strong coupling effect among the helical nano-wires. Therefore, it is expected to be a good candidate for generating phase shift and controlling wavefront with high efficiency. In this paper, using the finite-difference time-domain (FDTD) method, we studied the phase shift properties in the helical metamaterials. It is found that the phase shift occurs for both transmitted and reflected light waves. And the maximum of reflection coefficients can reach over 60%. In addition, the phase shift (φ) is dispersionless in the range of 600 nm to 860 nm, that is, it is only dominated by the initial angle (θ) of the helix. The relationship between them is φ = ± 2θ. Using Jones calculus we give a further explanation for these properties. Finally, by arranging the helixes in an array with a constant phase gradient, the phenomenon of anomalous refraction was also observed in a broad wavelength range.

  3. Helicity antenna showers for hadron colliders

    Science.gov (United States)

    Fischer, Nadine; Lifson, Andrew; Skands, Peter

    2017-10-01

    We present a complete set of helicity-dependent 2→ 3 antenna functions for QCD initial- and final-state radiation. The functions are implemented in the Vincia shower Monte Carlo framework and are used to generate showers for hadron-collider processes in which helicities are explicitly sampled (and conserved) at each step of the evolution. Although not capturing the full effects of spin correlations, the explicit helicity sampling does permit a significantly faster evaluation of fixed-order matrix-element corrections. A further speed increase is achieved via the implementation of a new fast library of analytical MHV amplitudes, while matrix elements from Madgraph are used for non-MHV configurations. A few examples of applications to QCD 2→ 2 processes are given, comparing the newly released Vincia 2.200 to Pythia 8.226.

  4. Neutrino's helicity in a gravitational field

    International Nuclear Information System (INIS)

    Pansart, J.P.

    1996-01-01

    By using approximated solutions of Dirac's equation, we show that there is no helicity reversal for light neutrinos in the Schwarzschild metric nor in an expanding universe. The actual coupling between a particle spin and the angular momentum of a heavy rotating body induces a possible helicity reversal but with an unobservable probability proportional to m 2 p / E 2 , where m p is the particle mass and E its energy. In these calculations, the helicity is defined through the spin orientation with respect to the current and not with respect to the linear momentum. This definition gives simple expressions and is equal to the usual definition in the case of a flat space. (N.T.)

  5. Single-superfield helical-phase inflation

    Energy Technology Data Exchange (ETDEWEB)

    Ketov, Sergei V., E-mail: ketov@tmu.ac.jp [Department of Physics, Tokyo Metropolitan University, Minami-ohsawa 1-1, Hachioji-shi, Tokyo 192-0397 (Japan); Kavli Institute for the Physics and Mathematics of the Universe (IPMU), The University of Tokyo, Chiba 277-8568 (Japan); Institute of Physics and Technology, Tomsk Polytechnic University, 30 Lenin Ave., Tomsk 634050 (Russian Federation); Terada, Takahiro, E-mail: takahiro@hep-th.phys.s.u-tokyo.ac.jp [Department of Physics, The University of Tokyo, Tokyo 113-0033 (Japan); Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg (Germany)

    2016-01-10

    Large-field inflation in supergravity requires the approximate global symmetry needed to protect flatness of the scalar potential. In helical-phase inflation, the U(1) symmetry of the Kähler potential is assumed, the phase part of the complex scalar of a chiral superfield plays the role of inflaton, and the radial part is strongly stabilized. The original model of helical phase inflation, proposed by Li, Li and Nanopoulos (LLN), employs an extra (stabilizer) superfield. We propose a more economical new class of the helical phase inflationary models without a stabilizer superfield. As the specific examples, the quadratic, the natural, and the Starobinsky-type inflationary models are studied in our approach.

  6. Resonant helical fields in the TBR tokamak

    International Nuclear Information System (INIS)

    Bender, O.W.

    1986-01-01

    The influence of external resonant helical fields (RHF) in the tokamak TBR plasma discharges was investigated. These fields were created by helical windings wounded on the TBR vessel with the same helicity of rational magnetic surfaces, producing resonant efects on these surfaces. The characteristics of the MHZ activity (amplitude, frequency and poloidal and toroidal wave numbers, m=2,3,4 and n=1, respectively) during the plasma discharges were modified by eletrical winding currents of the order of 2% of the plasma current. These characterisitics were measured for diferent discharges safety factors at the limiter (q) between 3 and 4, with and without the RHF, with the atenuation of the oscillation amplitudes and the increasing of their frequencies. The existente of expontaneous and induced magnetic islands were investigated. The data were compared with results obtained in other tokamaks. (author) [pt

  7. The helical structure of DNA facilitates binding

    International Nuclear Information System (INIS)

    Berg, Otto G; Mahmutovic, Anel; Marklund, Emil; Elf, Johan

    2016-01-01

    The helical structure of DNA imposes constraints on the rate of diffusion-limited protein binding. Here we solve the reaction–diffusion equations for DNA-like geometries and extend with simulations when necessary. We find that the helical structure can make binding to the DNA more than twice as fast compared to a case where DNA would be reactive only along one side. We also find that this rate advantage remains when the contributions from steric constraints and rotational diffusion of the DNA-binding protein are included. Furthermore, we find that the association rate is insensitive to changes in the steric constraints on the DNA in the helix geometry, while it is much more dependent on the steric constraints on the DNA-binding protein. We conclude that the helical structure of DNA facilitates the nonspecific binding of transcription factors and structural DNA-binding proteins in general. (paper)

  8. Remarks on manipulator classification and reversibility - deflection - backlash - inertia - balance and friction trade off

    International Nuclear Information System (INIS)

    Vertut, Jean.

    1976-01-01

    In a previous work the author proposed a time efficiency quotient based on time to perform a task for a man controlling a manipulator (RO MAN SY 73). This quotient is also a global evaluation of a man-manipulator system, and can be extended to teaching programmed manipulators. Classification based on this quotient emphasizes the importance of force feed-back to the operator, and enables to project the same concept to computer control. This paper concentrates on characteristics reflecting directly to the mechanics of the arm, to the actuators and to the control. They need delicate trade off: reversibility is key to force feed-back, deflection reflects on arm dynamics (oscillation) and precision, backlash allows lower friction but limits servo performances, inertia is high when limited deflection is required, friction is limiting the man in the loop performances, force transducers can compensate irreversibility and/or friction but lead to control sophistication. These trade offs are developed, and some proposed constants are given for force feed-back manipulators

  9. Nonideal, helical, vortical magnetohydrodynamic steady states

    International Nuclear Information System (INIS)

    Agim, Y.Z.; Montgomery, D.

    1991-01-01

    The helically-deformed profiles of driven, dissipative magnetohydrodynamic equilibria are constructed through second order in helical amplitude. The resultant plasma configurations are presented in terms of contour plots of magnetic flux function, pressure, current flux function and the mass flux function, along with the stability boundary at which they are expected to appear. For the Wisconsin Phaedrus-T Tokamak, plasma profiles with significant m = 3, n = 1 perturbation seem feasible; for these, the plasma pressure peaks off-axis. For the smaller aspect ratio case, the configuration with m 1,n =1 is thought to be relevant to the density perturbation observed in JET after a pellet injection. (author)

  10. Helical post stellarator. Part 1: Vacuum configuration

    International Nuclear Information System (INIS)

    Moroz, P.E.

    1997-08-01

    Results on a novel type of stellarator configuration, the Helical Post Stellarator (HPS), are presented. This configuration is different significantly from all previously known stellarators due to its unique geometrical characteristics and unique physical properties. Among those are: the magnetic field has only one toroidal period (M = 1), the plasma has an extremely low aspect ratio, A ∼ 1, and the variation of the magnetic field, B, along field lines features a helical ripple on the inside of the torus. Among the main advantages of a HPS for a fusion program are extremely compact, modular, and simple design compatible with significant rotational transform, large plasma volume, and improved particle transport characteristics

  11. Equilibrium studies of helical axis stellarators

    International Nuclear Information System (INIS)

    Hender, T.C.; Carreras, B.A.; Garcia, L.; Harris, J.H.; Rome, J.A.; Cantrell, J.L.; Lynch, V.E.

    1984-01-01

    The equilibrium properties of helical axis stellarators are studied with a 3-D equilibrium code and with an average method (2-D). The helical axis ATF is shown to have a toroidally dominated equilibrium shift and good equilibria up to at least 10% peak beta. Low aspect ratio heliacs, with relatively large toroidal shifts, are shown to have low equilibrium beta limits (approx. 5%). Increasing the aspect ratio and number of field periods proportionally is found to improve the equilibrium beta limit. Alternatively, increasing the number of field periods at fixed aspect ratio which raises and lowers the toroidal shift improves the equilibrium beta limit

  12. Sistema Basado en Casos para el diseño de engranajes cilíndricos con contacto exterior//Case based system for the design spur and helical external gear

    Directory of Open Access Journals (Sweden)

    Robert Hernández-Ortega

    2013-05-01

    Full Text Available El objetivo de este trabajo fue obtener un sistema Basado en Casos mediante la combinación del Razonamiento Basado en Casos y de las técnicas CAD CAE (Computer Aided Design, Computer Aided Engineering, para mejorar la utilización de la experiencia acumulada por los diseñadores, en la realización de nuevos diseños de transmisiones por engranajes cilíndricos con contacto exterior. La basede casos se obtuvo de la información almacenada en el archivo de diseño de una empresa de producciones mecánicas. La recuperación de las transmisiones se realiza combinando una consulta de selección y la técnica Vecino más Cercano. Como índices se utilizan los datos iniciales del diseño cuya importancia relativa se estableció mediante criterio de Experto. De esta manera, con la combinación de unsistema de gestión de bases de datos y un sistema CAD CAE resulta posible la reutilización de transmisiones diseñadas anteriormente, con o sin modificación, en nuevas aplicaciones.Palabras claves: razonamiento basado en casos, engranajes, diseño._______________________________________________________________________________AbstractThe aim of this work is to obtain a Case Based System by means of the combination of the Case Based Reasoning and CAD CAE (Computer Aided Design Computer Aided Engineering technique to improve the use of the accumulated experience by the designers in the realization of new spur and helical cylindrical external gear designs. The case base was obtained from the information stored in the design files of the mechanical productions company. The recovery of the transmissions is carried out combining a selection query and the nearest neighboring technique. The initial data of the design are used as indexeswhose relative importance settled down by means of Experts criteria. This way, the combination of database management system and CAD CAE system makes possible to use again previously designed transmissions, with or without

  13. Conversion from mutual helicity to self-helicity observed with IRIS

    Science.gov (United States)

    Li, L. P.; Peter, H.; Chen, F.; Zhang, J.

    2014-10-01

    Context. In the upper atmosphere of the Sun observations show convincing evidence for crossing and twisted structures, which are interpreted as mutual helicity and self-helicity. Aims: We use observations with the new Interface Region Imaging Spectrograph (IRIS) to show the conversion of mutual helicity into self-helicity in coronal structures on the Sun. Methods: Using far UV spectra and slit-jaw images from IRIS and coronal images and magnetograms from SDO, we investigated the evolution of two crossing loops in an active region, in particular, the properties of the Si IV line profile in cool loops. Results: In the early stage two cool loops cross each other and accordingly have mutual helicity. The Doppler shifts in the loops indicate that they wind around each other. As a consequence, near the crossing point of the loops (interchange) reconnection sets in, which heats the plasma. This is consistent with the observed increase of the line width and of the appearance of the loops at higher temperatures. After this interaction, the two new loops run in parallel, and in one of them shows a clear spectral tilt of the Si IV line profile. This is indicative of a helical (twisting) motion, which is the same as to say that the loop has self-helicity. Conclusions: The high spatial and spectral resolution of IRIS allowed us to see the conversion of mutual helicity to self-helicity in the (interchange) reconnection of two loops. This is observational evidence for earlier theoretical speculations. Movie associated with Fig. 1 and Appendix A are available in electronic form at http://www.aanda.org

  14. Use Deflected Trailing Edge to Improve the Aerodynamic Performance and Develop Low Solidity LPT Cascade

    Science.gov (United States)

    Chao, Li; Peigang, Yan; Xiangfeng, Wang; Wanjin, Han; Qingchao, Wang

    2017-08-01

    This paper investigates the feasibility of improving the aerodynamic performance of low pressure turbine (LPT) blade cascades and developing low solidity LPT blade cascades through deflected trailing edge. A deflected trailing edge improved aerodynamic performance of both LPT blade cascades and low solidity LPT blade cascades. For standard solidity LPT cascades, deflecting the trailing edge can decrease the energy loss coefficient by 20.61 % for a Reynolds number (Re) of 25,000 and freestream turbulence intensities (FSTI) of 1 %. For a low solidity LPT cascade, aerodynamic performance was also improved by deflecting the trailing edge. Solidity of the LPT cascade can be reduced by 12.5 % for blades with a deflected trailing edge without a drop in efficiency. Here, the flow control mechanism surrounding a deflected trailing edge was also revealed.

  15. The calculation of the deflection angle in a collision process between an atom of rare gas and a complex molecule of Xsub(n)Ysub(m) type

    International Nuclear Information System (INIS)

    Trisca, I.; Vasiu, M.; Vasaru, G.

    1987-01-01

    We report a classical method for the calculation of the angle of deflection in a nonresonant collision in Xsub(n)Ysub(m)-Z physical active systems. The classical turning point versus temperature, for UF 6 -Ar system was calculated. For small temperature has been pointed out the association interaction. (authors)

  16. The Effect of Material and Side Walls on Hull Deflection during a Blast Event

    Science.gov (United States)

    2017-12-13

    ARL-CR-0822 ● DEC 2017 US Army Research Laboratory The Effect of Material and Side Walls on Hull Deflection during a Blast Event...Army Research Laboratory The Effect of Material and Side Walls on Hull Deflection during a Blast Event prepared by Danielle Abell SURVICE...Walls on Hull Deflection during a Blast Event 5a. CONTRACT NUMBER W911QX-16-D-0014 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S

  17. Effective Moment Of Inertia And Deflections Of Reinforced Concrete Beams Under Long-Term Loading

    OpenAIRE

    Mahmood, Khalid M.; Ashour, Samir A.; Al-Noury, Soliman I.

    1995-01-01

    The paper presents a method for estimating long-term deflections of reinforced concrete beams by considering creep and shrinkage effects separately. Based on equilibrium and compatibility conditions a method is developed for investigating the properties of a cracked transformed section under sustained load. The concept of effective moment of inertia is extended to predict initial-plus-creep deflections. Long-term deflections computed by the proposed method are compared with the experimental r...

  18. Implications of resin-based composite (RBC) restoration on cuspal deflection and microleakage score in molar teeth: Placement protocol and restorative material.

    Science.gov (United States)

    McHugh, Lauren E J; Politi, Ioanna; Al-Fodeh, Rami S; Fleming, Garry J P

    2017-09-01

    To assess the cuspal deflection of standardised large mesio-occluso-distal (MOD) cavities in third molar teeth restored using conventional resin-based composite (RBC) or their bulk fill restorative counterparts compared with the unbound condition using a twin channel deflection measuring gauge. Following thermocycling, the cervical microleakage of the restored teeth was assessed to determine marginal integrity. Standardised MOD cavities were prepared in forty-eight sound third molar teeth and randomly allocated to six groups. Restorations were placed in conjunction with (and without) a universal bonding system and resin restorative materials were irradiated with a light-emitting-diode light-curing-unit. The dependent variable was the restoration protocol, eight oblique increments for conventional RBCs or two horizontal increments for the bulk fill resin restoratives. The cumulative buccal and palatal cuspal deflections from a twin channel deflection measuring gauge were summed, the restored teeth thermally fatigued, immersed in 0.2% basic fuchsin dye for 24h, sectioned and examined for cervical microleakage score. The one-way analysis of variance (ANOVA) identified third molar teeth restored using conventional RBC materials had significantly higher mean total cuspal deflection values compared with bulk fill resin restorative restoration (all pmaterial selection is vital in the absence of clinical data. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  19. Drift reversal capability in helical systems

    International Nuclear Information System (INIS)

    Yokoyama, M.; Itoh, K.; Okamura, S.

    2002-10-01

    The maximum-J (J is the second adiabatic invariant) capability, i.e., the drift reversal capability, is examined in quasi-axisymmetric (QAS) stellarators and quasi-poloidally symmetric (QPS) stellarators as a possible mechanism for turbulent transport suppression. Due to the existence of non-axisymmetry of the magnetic field strength in QAS configurations, a local maximum of J is created to cause the drift reversal. The increase of magnetic shear in finite beta equilibria also has favorable effect in realizing the drift reversal. The radial variation of the uniform magnetic field component plays a crucial role for the drift reversal in a QPS configuration. Thus, the drift reversal capability and its external controllability are demonstrated for QAS and QPS stellarators, by which the impact of magnetic configuration on turbulent transport can be studied in experiments. (author)

  20. Drift reversal capability in helical systems

    International Nuclear Information System (INIS)

    Yokoyama, M.; Itoh, K.; Okamura, S.; Matsuoka, K.; Nakajima, N.; Itoh, S.-I.; Neilson, G.H.; Zarnstorff, M.C.; Rewoldt, G.

    2003-01-01

    The maximum-J (J is the second adiabatic invariant) capability, i.e., the drift reversal capability, is examined in quasi-axisymmetric (QAS) stellarators and quasi-poloidally symmetric (QPS) stellarators as a possible mechanism for turbulent transport suppression. Due to the existence of non-axisymmetry of the magnetic field strength in QAS configurations, a local maximum of J is created to cause the drift reversal. The increase of magnetic shear in finite beta equilibria also has favorable effect in realizing the drift reversal. The radial variation of the uniform magnetic field component plays a crucial role for the drift reversal in a QPS configuration. Thus, the drift reversal capability and its external controllability are demonstrated for QAS and QPS stellarators, by which the impact of magnetic configuration on turbulent transport can be studied in experiments. (author)

  1. Light deflection, lensing, and time delays from gravitational potentials and Fermat's principle in the presence of a cosmological constant

    International Nuclear Information System (INIS)

    Ishak, Mustapha

    2008-01-01

    The contributions of the cosmological constant to the deflection angle and the time delays are derived from the integration of the gravitational potential as well as from Fermat's principle. The findings are in agreement with recent results using exact solutions to Einstein's equations and reproduce precisely the new Λ term in the bending angle and the lens equation. The consequences on time-delay expressions are explored. While it is known that Λ contributes to the gravitational time delay, it is shown here that a new Λ term appears in the geometrical time delay as well. Although these newly derived terms are perhaps small for current observations, they do not cancel out as previously claimed. Moreover, as shown before, at galaxy cluster scale, the Λ contribution can be larger than the second-order term in the Einstein deflection angle for several cluster lens systems.

  2. Mikro-Elektro-Mechanisches System und Verfahren zum Herstellen desselben

    OpenAIRE

    Lisec, Thomas; Stoppel, Fabian

    2015-01-01

    A microelectromechanical system comprises a deflectable actuator plate and a stop surface. An integral piezoelectric functional layer of the deflectable actuator plate is formed over an area (APS) of the actuator plate. The deflectable actuator plate is designed to implement a concave curvature in at least one driven or non-driven state, wherein the stop surface is arranged in a manner facing a concave side of the deflectable actuator plate defined by the concave curvature. The deflectable ac...

  3. Dynamics and deformability of α-, 310- and π-helices

    Directory of Open Access Journals (Sweden)

    Narwani Tarun Jairaj

    2018-01-01

    Full Text Available Protein structures are often represented as seen in crystals as (i rigid macromolecules (ii with helices, sheets and coils. However, both definitions are partial because (i proteins are highly dynamic macromolecules and (ii the description of protein structures could be more precise. With regard to these two points, we analyzed and quantified the stability of helices by considering α-helices as well as 310- and π-helices. Molecular dynamic (MD simulations were performed on a large set of 169 representative protein domains. The local protein conformations were followed during each simulation and analyzed. The classical flexibility index (B-factor was confronted with the MD root mean square flexibility (RMSF index. Helical regions were classified according to their level of helicity from high to none. For the first time, a precise quantification showed the percentage of rigid and flexible helices that underlie unexpected behaviors. Only 76.4% of the residues associated with α-helices retain the conformation, while this tendency drops to 40.5% for 310-helices and is never observed for π-helices. α-helix residues that do not remain as an α-helix have a higher tendency to assume β-turn conformations than 310- or π-helices. The 310-helices that switch to the α-helix conformation have a higher B-factor and RMSF values than the average 310-helix but are associated with a lower accessibility. Rare π-helices assume a β-turn, bend and coil conformations, but not α- or 310-helices. The view on π-helices drastically changes with the new DSSP (Dictionary of Secondary Structure of Proteins assignment approach, leading to behavior similar to 310-helices, thus underlining the importance of secondary structure assignment methods.

  4. Review of the helicity formalism; Revision del formalismo de helicidad

    Energy Technology Data Exchange (ETDEWEB)

    Barreiro, F; Cerrada, M; Fernandez, E

    1972-07-01

    Our purpose in these notes has been to present a brief and general review of the helicity formalism. We begin by discussing Lorentz invariance, spin and helicity ideas, in section 1 . In section 2 we deal with the construction of relativistic states and scattering amplitudes in the helicity basis and we study their transformation properties under discrete symmetries. Finally we present some more sophisticated topics like kinematical singularities of helicity amplitudes, kinematical constraints and crossing relations 3, 4, 5 respectively. (Author) 8 refs.

  5. Robust integer and fractional helical modes in the quantum Hall effect

    Science.gov (United States)

    Ronen, Yuval; Cohen, Yonatan; Banitt, Daniel; Heiblum, Moty; Umansky, Vladimir

    2018-04-01

    Electronic systems harboring one-dimensional helical modes, where spin and momentum are locked, have lately become an important field of their own. When coupled to a conventional superconductor, such systems are expected to manifest topological superconductivity; a unique phase hosting exotic Majorana zero modes. Even more interesting are fractional helical modes, yet to be observed, which open the route for realizing generalized parafermions. Possessing non-Abelian exchange statistics, these quasiparticles may serve as building blocks in topological quantum computing. Here, we present a new approach to form protected one-dimensional helical edge modes in the quantum Hall regime. The novel platform is based on a carefully designed double-quantum-well structure in a GaAs-based system hosting two electronic sub-bands; each tuned to the quantum Hall effect regime. By electrostatic gating of different areas of the structure, counter-propagating integer, as well as fractional, edge modes with opposite spins are formed. We demonstrate that, due to spin protection, these helical modes remain ballistic over large distances. In addition to the formation of helical modes, this platform can serve as a rich playground for artificial induction of compounded fractional edge modes, and for construction of edge-mode-based interferometers.

  6. Helical edge states and fractional quantum Hall effect in a graphene electron-hole bilayer.

    Science.gov (United States)

    Sanchez-Yamagishi, Javier D; Luo, Jason Y; Young, Andrea F; Hunt, Benjamin M; Watanabe, Kenji; Taniguchi, Takashi; Ashoori, Raymond C; Jarillo-Herrero, Pablo

    2017-02-01

    Helical 1D electronic systems are a promising route towards realizing circuits of topological quantum states that exhibit non-Abelian statistics. Here, we demonstrate a versatile platform to realize 1D systems made by combining quantum Hall (QH) edge states of opposite chiralities in a graphene electron-hole bilayer at moderate magnetic fields. Using this approach, we engineer helical 1D edge conductors where the counterpropagating modes are localized in separate electron and hole layers by a tunable electric field. These helical conductors exhibit strong non-local transport signals and suppressed backscattering due to the opposite spin polarizations of the counterpropagating modes. Unlike other approaches used for realizing helical states, the graphene electron-hole bilayer can be used to build new 1D systems incorporating fractional edge states. Indeed, we are able to tune the bilayer devices into a regime hosting fractional and integer edge states of opposite chiralities, paving the way towards 1D helical conductors with fractional quantum statistics.

  7. Force-Sensor-Based Estimation of Needle Tip Deflection in Brachytherapy

    Directory of Open Access Journals (Sweden)

    Thomas Lehmann

    2013-01-01

    in real time during needle insertion is the main contribution of this paper. The proposed approach solely relies on the measured forces and torques without a need for any other invasive/noninvasive sensing devices. A few mechanical models have been introduced previously regarding the way the forces are composed along the needle during insertion; we will compare our model to those approaches in terms of accuracy. In order to conduct experiments to verify the deflection model, a custom-built, 2-DOF robotic system for needle insertion is developed and discussed. This system is a prototype of an intelligent, hand-held surgical assistant tool that incorporates the virtual sensor proposed in this paper.

  8. Exabyte helical scan devices at Fermilab

    International Nuclear Information System (INIS)

    Constanta-Fanourakis, P.; Kaczar, K.; Oleynik, G.; Petravick, D.; Votava, M.; White, V.; Hockney, G.; Bracker, S.; de Miranda, J.M.

    1989-05-01

    Exabyte 8mm helical scan storage devices are in use at Fermilab in a number of applications. These devices have the functionality of magnetic tape, but use media which is much more economical and much more dense than conventional 9 track tape. 6 refs., 3 figs

  9. Topological characteristics of helical repeat proteins

    NARCIS (Netherlands)

    Groves, M R; Barford, D

    The recent elucidation of protein structures based upon repeating amino acid motifs, including the armadillo motif, the HEAT motif and tetratricopeptide repeats, reveals that they belong to the class of helical repeat proteins. These proteins share the common property of being assembled from tandem

  10. A Prospective Evaluation of Helical Tomotherapy

    International Nuclear Information System (INIS)

    Bauman, Glenn; Yartsev, Slav; Rodrigues, George; Lewis, Craig; Venkatesan, Varagur M.; Yu, Edward; Hammond, Alex; Perera, Francisco; Ash, Robert; Dar, A. Rashid; Lock, Michael; Baily, Laura; Coad, Terry C; Trenka, Kris C.; Warr, Barbara; Kron, Tomas; Battista, Jerry; Van Dyk, Jake

    2007-01-01

    Purpose: To report results from two clinical trials evaluating helical tomotherapy (HT). Methods and Materials: Patients were enrolled in one of two prospective trials of HT (one for palliative and one for radical treatment). Both an HT plan and a companion three-dimensional conformal radiotherapy (3D-CRT) plan were generated. Pretreatment megavoltage computed tomography was used for daily image guidance. Results: From September 2004 to January 2006, a total of 61 sites in 60 patients were treated. In all but one case, a clinically acceptable tomotherapy plan for treatment was generated. Helical tomotherapy plans were subjectively equivalent or superior to 3D-CRT in 95% of plans. Helical tomotherapy was deemed equivalent or superior in two thirds of dose-volume point comparisons. In cases of inferiority, differences were either clinically insignificant and/or reflected deliberate tradeoffs to optimize the HT plan. Overall imaging and treatment time (median) was 27 min (range, 16-91 min). According to a patient questionnaire, 78% of patients were satisfied to very satisfied with the treatment process. Conclusions: Helical tomotherapy demonstrated clear advantages over conventional 3D-CRT in this diverse patient group. The prospective trials were helpful in deploying this technology in a busy clinical setting

  11. Micropipette Deflection Measurements of Agar-Glass Adhesion

    Science.gov (United States)

    Parg, Richard; Shelton, Erin; Dutcher, John

    Micropipette deflection experiments were used to study the adhesive strength at an agar-glass interface. Agar is a hydrogel commonly used in biological research; however, many of the mechanical properties of this hydrogel are not well characterized. By measuring the peak force required to slide an agar puck supported by a Teflon ring across a clean glass slide, we are able to compare the adhesive strength of 1 % w/w and 1.5 % w/w agar. On average, the force required to break the agar-glass interface was approximately a factor of 2 larger for 1.5 % w/w agar than for 1 % w/w agar. We discuss this result within the context of a simple model of agar adhesion. Additional experiments were performed to measure the kinetic friction between agar and glass to obtain insight into its dependence on agar concentration.

  12. Modified method for registration of particle deflection by bent crystal

    International Nuclear Information System (INIS)

    Afanas'ev, S.V.; Kovalenko, A.D.; Kuznetsov, V.N.; Romanov, S.V.; Sajfulin, Sh.Z.; Taratin, A.M.; Volkov, V.I.; Voevodin, M.A.; Bojko, V.V.

    2003-01-01

    The modified method for registration of particle deflection by a bent crystal was proposed and studied at the external proton beam of the Nuclotron. The telescope of scintillation counters was placed at the angle that was smaller than a crystal bending angle. The count dependence of the telescope on the crystal orientation was formed by the particles, which passed in channeling states only some part of the crystal length. Two maximums were observed in the dependencies due to particles captured into the channeling states on the crystal surface and in the crystal volume. This allows one to obtain, using the telescope and high-intensity beams, useful data about the particle channeling and the crystal, which usually demands more complicated registration by means of the coordinate detectors

  13. Photothermal cantilever deflection spectroscopy of a photosensitive polymer

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Minhyuk; Lee, Dongkyu; Jung, Namchul; Jeon, Sangmin [Department of Chemical Engineering, Pohang University of Science and Technology, Pohang (Korea, Republic of); Kim, Seonghwan; Chae, Inseok; Thundat, Thomas [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada)

    2012-05-14

    The mechanical and chemical information of a poly(methyl methacrylate) (PMMA) film on a microcantilever were simultaneously acquired by photothermal cantilever deflection spectroscopy as a function of ultraviolet (UV) irradiation time. Nanomechanical infrared (IR) spectra from the PMMA-coated microcantilever agreed well with the Fourier transform infrared spectroscopy (FTIR) spectra of PMMA on gold-coated silicon wafer. The decreasing intensities of nanomechanical IR peaks represent chemical as well as mechanical information of UV radiation-induced photodegradation processes in the PMMA which cannot be obtained by a conventional FTIR technique. The observed decrease in the resonance frequency of the microcantilever is related to the change in the Young's modulus of the PMMA under UV exposure.

  14. Fabrication and Testing of Deflecting Cavities for APS

    Energy Technology Data Exchange (ETDEWEB)

    Mammosser, John; Wang, Haipeng; Rimmer, Robert; Jim, Henry; Katherine, Wilson; Dhakal, Pashupati; Ali, Nassiri; Jim, Kerby; Jeremiah, Holzbauer; Genfa, Wu; Joel, Fuerst; Yawei, Yang; Zenghai, Li

    2013-09-01

    Jefferson Lab (Newport News, Virginia) in collaboration with Argonne National Laboratory (Argonne, IL) has fabricated and tested four first article, 2.8 GHz, deflecting SRF cavities, for Argonne's Short-Pulse X-ray (SPX) project. These cavities are unique in many ways including the fabrication techniques in which the cavity cell and waveguides were fabricated. These cavity subcomponents were milled from bulk large grain niobium ingot material directly from 3D CAD files. No forming of sub components was used with the exception of the beam-pipes. The challenging cavity and helium vessel design and fabrication results from the stringent RF performance requirements required by the project and operation in the APS ring. Production challenges and fabrication techniques as well as testing results will be discussed in this paper.

  15. Current deflection NDE for pipeline inspection and monitoring

    Science.gov (United States)

    Jarvis, Rollo; Cawley, Peter; Nagy, Peter B.

    2016-02-01

    Failure of oil and gas pipelines can often be catastrophic, therefore routine inspection for time dependent degradation is essential. In-line inspection is the most common method used; however, this requires the insertion and retrieval of an inspection tool that is propelled by the fluid in the pipe and risks becoming stuck, so alternative methods must often be employed. This work investigates the applicability of a non-destructive evaluation technique for both the detection and growth monitoring of defects, particularly corrosion under insulation. This relies on injecting an electric current along the pipe and indirectly measuring the deflection of current around defects from perturbations in the orthogonal components of the induced magnetic flux density. An array of three orthogonally oriented anisotropic magnetoresistive sensors has been used to measure the magnetic flux density surrounding a 6'' schedule-40 steel pipe carrying 2 A quasi-DC axial current. A finite element model has been developed that predicts the perturbations in magnetic flux density caused by current deflection which has been validated by experimental results. Measurements of the magnetic flux density at 50 mm lift-off from the pipe surface are stable and repeatable to the order of 100 pT which suggests that defect detection or monitoring growth of corrosion-type defects may be possible with a feasible magnitude of injected current. Magnetic signals are additionally incurred by changes in the wall thickness of the pipe due to manufacturing tolerances, and material property variations. If a monitoring scheme using baseline subtraction is employed then the sensitivity to defects can be improved while avoiding false calls.

  16. Theory of using magnetic deflections to combine charged particle beams

    Energy Technology Data Exchange (ETDEWEB)

    Steckbeck, Mackenzie K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Doyle, Barney Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    Several radiation effects projects in the Ion Beam Lab (IBL) have recently required two disparate charged particle beams to simultaneously strike a single sample through a single port of the target chamber. Because these beams have vastly different mass–energy products (MEP), the low-MEP beam requires a large angle of deflection toward the sample by a bending electromagnet. A second electromagnet located further upstream provides a means to compensate for the small angle deflection experienced by the high-MEP beam during its path through the bending magnet. This paper derives the equations used to select the magnetic fields required by these two magnets to achieve uniting both beams at the target sample. A simple result was obtained when the separation of the two magnets was equivalent to the distance from the bending magnet to the sample, and the equation is given by: Bs= 1/2(rc/rs) Bc, where Bs and Bc are the magnetic fields in the steering and bending magnet and rc/rs is the ratio of the radii of the bending magnet to that of the steering magnet. This result is not dependent upon the parameters of the high MEP beam, i.e. energy, mass, charge state. Therefore, once the field of the bending magnet is set for the low-MEP beam, and the field in the steering magnet is set as indicted in the equation, the trajectory path of any high-MEP beam will be directed into the sample.

  17. Helicity-flip in particle production on nuclei

    International Nuclear Information System (INIS)

    Faeldt, G.

    1977-01-01

    Coherent nuclear production processes are generally analyzed assuming helicity conserving production amplitudes. In view of the uncertainties of the actual helicity structure this could be a dangerous assumption. It is shown that helicity-flip contributions might be part of the explanation of the small effective (pππ)-nucleon cross sections observed in coherent production. (Auth.)

  18. A real-scale helical coil winding trial of the Large Helical Device

    International Nuclear Information System (INIS)

    Senba, T.; Yamamoto, T.; Tamaki, T.; Asano, K.; Suzuki, S.; Yamauchi, T.; Uchida, K.; Nakanishi, K.; Yamagiwa, T.; Suzuki, S.; Miyoshi, R.; Sasa, H.; Watanabe, S.; Tatemura, M.; Hatada, N.; Yamaguchi, S.; Imagawa, S.; Yanagi, N.; Satow, T.; Yamamoto, J.; Motojima, O.

    1995-01-01

    A real-scale helical coil winding trial of the Large Helical Device (LHD) has been conducted for a study of coil winding configuration and winding methods and for exhibiting the state of the art. It includes construction and test run of a specifically designed winding machine and development of various manufacturing methods for accurate coil winding. It has been carried out in Hitachi Works before in situ winding, and has provided much needed engineering data for construction of the LHD. (orig.)

  19. Transport properties of a discrete helical electrostatic quadrupole

    International Nuclear Information System (INIS)

    Meitzler, C.R.; Antes, K.; Datte, P.; Huson, F.R.; Xiu, L.

    1991-01-01

    The helical electrostatic quadrupole (HESQ) lens has been proposed as a low energy beam transport system which permits intense H - beams to be focused into an RFQ without seriously increasing the beam's emittance. A stepwise continuous HESQ lens has been constructed, and preliminary tests have shown that the structure does provide focusing. In order to understand the transport properties of this device, further detailed studies have been performed. Emittances were measured 3.5 cm from the end of the HESQ at two different voltages on the HESQ electrodes. A comparison of these experimental results with a linear model of the HESQ beam transport is made. 4 refs., 5 figs

  20. Permeation Barrier Coatings for the Helical Heat Exchanger

    International Nuclear Information System (INIS)

    Korinko, P.S.

    1999-01-01

    A permeation barrier coating was specified for the Helical Heat Exchanger (HHE) to minimize contamination through emissions and/or permeation into the nitrogen system for ALARA reasons. Due to the geometry of the HHE, a special coating practice was needed since the conventional method of high temperature pack aluminization was intractable. A survey of many coating companies was undertaken; their coating capabilities and technologies were assessed and compared to WSRC needs. The processes and limitations to coating the HHE are described. Slurry coating appears to be the most technically sound approach for coating the HHE

  1. Helical computed tomography and the workstation: introduction to a symbiosis

    International Nuclear Information System (INIS)

    Garcia-Santos, J.M.

    1997-01-01

    We do a brief introduction to the possibilities of an helical computed tomography system when it is associated with a powerful workstation. The fast and volumetric way of acquisition constitutes, basically, the main advantage of this sort of computed tomography. The anatomical and radio pathological study, in a workstation, of the acquired information (thanks to multiplanar and 3D reconstruction), increases significantly our capacity of analysis in each patient. Only the clinical and radiological experience will tell us which is the right place that this symbiosis occupies within our diagnosis tools. (Author) 11 refs

  2. Water-Cut Sensor System

    KAUST Repository

    Karimi, Muhammad Akram

    2018-01-11

    Provided in some embodiments is a method of manufacturing a pipe conformable water-cut sensors system. Provided in some embodiments is method for manufacturing a water-cut sensor system that includes providing a helical T-resonator, a helical ground conductor, and a separator at an exterior of a cylindrical pipe. The helical T-resonator including a feed line, and a helical open shunt stub conductively coupled to the feed line. The helical ground conductor including a helical ground plane opposite the helical open shunt stub and a ground ring conductively coupled to the helical ground plane. The feed line overlapping at least a portion of the ground ring, and the separator disposed between the feed line and the portion of the ground ring overlapped by the feed line to electrically isolate the helical T-resonator from the helical ground conductor.

  3. Development of a helical-coil double wall tube steam generator for 4S reactor

    International Nuclear Information System (INIS)

    Kitajima, Yuko; Maruyama, Shigeki; Jimbo, Noboru; Hino, Takehisa; Sato, Katsuhiko

    2011-01-01

    The 4S, Super-Safe Small and Simple, is a small-sized sodium-cooled fast reactor. A fast reactor usually uses sodium as a coolant to transfer heat from core to turbine/generator system. The heat of the intermediate heat transport system and that of the water stream systems are exchanged by the steam generator (SG) tubes. If the tube failure occurs, a sodium/water reaction could be occurred. To prevent the reaction and enhance safety, a helical-coil-type double wall tube with wire mesh interlayer and continuous monitoring systems of tube failure are applied to the SG of the 4S. The development and general features of this type double wall tube were described in Ref. 1) and Ref. 2). Those paper summarized following results; The tubes studied in these references were straight type. To establish this SG, development of manufacturing method of helical-coil-type double wall tube and validation of the tube failure monitoring system are needed. In this study, three demonstration tests have been performed; welding test of the double wall tube to manufacture the tubes with 70-80m length, assembling test of the helical-coil tube, and confirmation test of the tube processing system using the fabricated helical-coil tubes. As a result, following technologies have been successfully established. (1) Development of the welding techniques for manufacturing of the helical-coil-type double wall tube with wire mesh interlayer. (2) The confirmation test for manufacturing the helical coil tube of the SG. (author)

  4. Bearing capacity of helical pile foundation in peat soil from different, diameter and spacing of helical plates

    Science.gov (United States)

    Fatnanta, F.; Satibi, S.; Muhardi

    2018-03-01

    In an area dominated by thick peat soil layers, driven piles foundation is often used. These piles are generally skin friction piles where the pile tips do not reach hard stratum. Since the bearing capacity of the piles rely on the resistance of their smooth skin, the bearing capacity of the piles are generally low. One way to increase the bearing capacity of the piles is by installing helical plates around the pile tips. Many research has been performed on helical pile foundation. However, literature on the use of helical pile foundation on peat soil is still hardly found. This research focus on the study of axial bearing capacity of helical pile foundation in peat soil, especially in Riau Province. These full-scale tests on helical pile foundation were performed in a rectangular box partially embedded into the ground. The box is filled with peat soil, which was taken from Rimbo Panjang area in the district of Kampar, Riau Province. Several helical piles with different number, diameter and spacing of the helical plates have been tested and analysed. The tests result show that helical pile with three helical plates of uniform diameter has better bearing capacity compared to other helical piles with varying diameter and different number of helical plates. The bearing capacity of helical pile foundation is affected by the spacing between helical plates. It is found that the effective helical plates spacing for helical pile foundation with diameter of 15cm to 35cm is between 20cm to 30cm. This behaviour may be considered to apply to other type of helical pile foundations in peat soil.

  5. Pyrolysis of Helical Coordination Polymers for Metal-Sulfide-Based Helices with Broadband Chiroptical Activity.

    Science.gov (United States)

    Hirai, Kenji; Yeom, Bongjun; Sada, Kazuki

    2017-06-27

    Fabrication of chiroptical materials with broadband response in the visible light region is vital to fully realize their potential applications. One way to achieve broadband chiroptical activity is to fabricate chiral nanostructures from materials that exhibit broadband absorption in the visible light region. However, the compounds used for chiroptical materials have predominantly been limited to materials with narrowband spectral response. Here, we synthesize Ag 2 S-based nanohelices derived from helical coordination polymers. The right- and left-handed coordination helices used as precursors are prepared from l- and d-glutathione with Ag + and a small amount of Cu 2+ . The pyrolysis of the coordination helices yields right- and left-handed helices of Cu 0.12 Ag 1.94 S/C, which exhibit chiroptical activity spanning the entire visible light region. Finite element method simulations substantiate that the broadband chiroptical activity is attributed to synergistic broadband light absorption and light scattering. Furthermore, another series of Cu 0.10 Ag 1.90 S/C nanohelices are synthesized by choosing the l- or d-Glu-Cys as starting materials. The pitch length of nanohelicies is controlled by changing the peptides, which alters their chiroptical properties. The pyrolysis of coordination helices enables one to fabricate helical Ag 2 S-based materials that enable broadband chiroptical activity but have not been explored owing to the lack of synthetic routes.

  6. First measurement of the helicity-dependent (vector)({gamma})(vector)(p){yields}p{eta} differential cross-section

    Energy Technology Data Exchange (ETDEWEB)

    Ahrens, J.; Arends, H.J.; Aulenbacher, K.; Beck, R.; Drechsel, D.; Harrach, D. van; Heid, E. [Institut fuer Kernphysik, Universitaet Mainz, D-55099 Mainz (Germany); Altieri, S. [INFN, Sezione di Pavia, I-27100 Pavia (Italy); Dipartimento di Fisica Nucleare e Teorica, Universita di Pavia, I-27100 Pavia (Italy); Annand, J.R.M. [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Anton, G. [Physikalisches Institut, Universitaet Erlangen-Nuernberg, D-91058 Erlangen (Germany); Bradtke, C.; Goertz, S.; Harmsen, J. [Institut fuer Experimentalphysik, Ruhr-Universitaet Bochum, D-44801 Bochum (Germany); Braghieri, A. [INFN, Sezione di Pavia, I-27100 Pavia (Italy); d' Hose, N. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette Cedex (France); Dutz, H. [Physikalisches Institut, Universitaet Bonn, D-53115 Bonn (Germany); Grabmayr, P. [Physikalisches Institut, Universitaet Tuebingen, D-72076 Tuebingen (Germany); Hansen, K. [Department of Physics, University of Lund, Lund (Sweden); Hasegawa, S. [Department of Physics, Nagoya University, Chikusa-ku, Nagoya (Japan); Hasegawa, T. [Faculty of Engineering, Miyazaki University, Miyazaki (Japan); Helbing, K.; Holvoet, H.; Van Hoorebeke, L.; Horikawa, N.; Iwata, T.; Jahn, O.; Jennewein, P.; Kageya, T.; Kiel, B.; Klein, F.; Kondratiev, R.; Kossert, K.; Krimmer, J.; Lang, M.; Lannoy, B.; Leukel, R.; Lisin, V.; Matsuda, T.; McGeorge, J.C.; Meier, A.; Menze, D.; Meyer, W.; Michel, T.; Naumann, J.; Panzeri, A.; Pedroni, P.; Pinelli, T.; Preobrajenski, I.; Radtke, E.; Reichert, E.; Reicherz, G.; Rohlof, Ch.; Rosner, G.; Ryckbosch, D.; Sauer, M.; Schoch, B.; Schumacher, M.; Seitz, B.; Speckner, T.; Takabayashi, N.; Tamas, G.; Thomas, A.; Van de Vyver, R.; Wakai, A.; Weihofen, W.; Wissmann, F.; Zapadtka, F.; Zeitler, G.

    2003-06-01

    The helicity dependence of the (vector)({gamma})(vector)(p){yields}p{eta} reaction has been measured for the first time at a center-of-mass angle {theta}{sup *}{sub {eta}}=70 in the photon energy range from 780 MeV to 790 MeV. The experiment, performed at the Mainz microtron MAMI, used a 4{pi}-detector system, a circularly polarized, tagged photon beam, and a longitudinally polarized frozen-spin target. The helicity 3/2 cross-section is found to be small and the results for helicity 1/2 agree with predictions from the MAID analysis. (orig.)

  7. First measurement of the helicity-dependent vector gamma)vector(p)->p eta differential cross-section

    CERN Document Server

    Ahrens, J; Aulenbacher, K; Beck, R; Drechsel, D; Von Harrach, D; Heid, E; Altieri, S; Annand, J R M; Anton, G; Bradtke, C; Görtz, S; Harmsen, J; Braghieri, A; D'Hose, N; Dutz, H; Grabmayr, P; Hansen, K; Hasegawa, S; Hasegawa, T; Helbing, K; Holvoet, H; Van Hoorebeke, L; Horikawa, N; Iwata, T; Jahn, O; Jennewein, P; Kageya, T; Kiel, B; Klein, F; Kondratiev, R; Kossert, K; Krimmer, J; Lang, M; Lannoy, B; Leukel, R; Lisin, V; Matsuda, T; McGeorge, J C; Meier, A; Menze, D; Meyer, Werner T; Michel, T; Naumann, J; Panzeri, A; Pedroni, P; Pinelli, T; Preobrajenski, I; Radtke, E; Reichert, E; Reicherz, G; Rohlof, C; Rosner, G; Ryckbosch, D; Sauer, M C; Schoch, B; Schumacher, M; Seitz, B; Speckner, T; Takabayashi, N; Tamas, G; Thomas, A; Van De Vyver, R; Wakai, A; Weihofen, W; Wissmann, F; Zapadtka, F; Zeitler, G

    2003-01-01

    The helicity dependence of the vector(gamma)vector(p)->p eta reaction has been measured for the first time at a center-of-mass angle theta sup * subeta=70 in the photon energy range from 780 MeV to 790 MeV. The experiment, performed at the Mainz microtron MAMI, used a 4 pi-detector system, a circularly polarized, tagged photon beam, and a longitudinally polarized frozen-spin target. The helicity 3/2 cross-section is found to be small and the results for helicity 1/2 agree with predictions from the MAID analysis. (orig.)

  8. A rigid motion correction method for helical computed tomography (CT)

    International Nuclear Information System (INIS)

    Kim, J-H; Kyme, A; Fulton, R; Nuyts, J; Kuncic, Z

    2015-01-01

    We propose a method to compensate for six degree-of-freedom rigid motion in helical CT of the head. The method is demonstrated in simulations and in helical scans performed on a 16-slice CT scanner. Scans of a Hoffman brain phantom were acquired while an optical motion tracking system recorded the motion of the bed and the phantom. Motion correction was performed by restoring projection consistency using data from the motion tracking system, and reconstructing with an iterative fully 3D algorithm. Motion correction accuracy was evaluated by comparing reconstructed images with a stationary reference scan. We also investigated the effects on accuracy of tracker sampling rate, measurement jitter, interpolation of tracker measurements, and the synchronization of motion data and CT projections. After optimization of these aspects, motion corrected images corresponded remarkably closely to images of the stationary phantom with correlation and similarity coefficients both above 0.9. We performed a simulation study using volunteer head motion and found similarly that our method is capable of compensating effectively for realistic human head movements. To the best of our knowledge, this is the first practical demonstration of generalized rigid motion correction in helical CT. Its clinical value, which we have yet to explore, may be significant. For example it could reduce the necessity for repeat scans and resource-intensive anesthetic and sedation procedures in patient groups prone to motion, such as young children. It is not only applicable to dedicated CT imaging, but also to hybrid PET/CT and SPECT/CT, where it could also ensure an accurate CT image for lesion localization and attenuation correction of the functional image data. (paper)

  9. Computing the Deflection of the Vertical for Improving Aerial Surveys: A Comparison between EGM2008 and ITALGEO05 Estimates

    Directory of Open Access Journals (Sweden)

    Riccardo Barzaghi

    2016-07-01

    Full Text Available Recent studies on the influence of the anomalous gravity field in GNSS/INS applications have shown that neglecting the impact of the deflection of vertical in aerial surveys induces horizontal and vertical errors in the measurement of an object that is part of the observed scene; these errors can vary from a few tens of centimetres to over one meter. The works reported in the literature refer to vertical deflection values based on global geopotential model estimates. In this paper we compared this approach with the one based on local gravity data and collocation methods. In particular, denoted by ξ and η, the two mutually-perpendicular components of the deflection of the vertical vector (in the north and east directions, respectively, their values were computed by collocation in the framework of the Remove-Compute-Restore technique, applied to the gravity database used for estimating the ITALGEO05 geoid. Following this approach, these values have been computed at different altitudes that are relevant in aerial surveys. The (ξ, η values were then also estimated using the high degree EGM2008 global geopotential model and compared with those obtained in the previous computation. The analysis of the differences between the two estimates has shown that the (ξ, η global geopotential model estimate can be reliably used in aerial navigation applications that require the use of sensors connected to a GNSS/INS system only above a given height (e.g., 3000 m in this paper that must be defined by simulations.

  10. Biot-Savart helicity versus physical helicity: A topological description of ideal flows

    Science.gov (United States)

    Sahihi, Taliya; Eshraghi, Homayoon

    2014-08-01

    For an isentropic (thus compressible) flow, fluid trajectories are considered as orbits of a family of one parameter, smooth, orientation-preserving, and nonsingular diffeomorphisms on a compact and smooth-boundary domain in the Euclidian 3-space which necessarily preserve a finite measure, later interpreted as the fluid mass. Under such diffeomorphisms the Biot-Savart helicity of the pushforward of a divergence-free and tangent to the boundary vector field is proved to be conserved and since these circumstances present an isentropic flow, the conservation of the "Biot-Savart helicity" is established for such flows. On the other hand, the well known helicity conservation in ideal flows which here we call it "physical helicity" is found to be an independent constant with respect to the Biot-Savart helicity. The difference between these two helicities reflects some topological features of the domain as well as the velocity and vorticity fields which is discussed and is shown for simply connected domains the two helicities coincide. The energy variation of the vorticity field is shown to be formally the same as for the incompressible flow obtained before. For fluid domains consisting of several disjoint solid tori, at each time, the harmonic knot subspace of smooth vector fields on the fluid domain is found to have two independent base sets with a special type of orthogonality between these two bases by which a topological description of the vortex and velocity fields depending on the helicity difference is achieved since this difference is shown to depend only on the harmonic knot parts of velocity, vorticity, and its Biot-Savart vector field. For an ideal magnetohydrodynamics (MHD) flow three independent constant helicities are reviewed while the helicity of magnetic potential is generalized for non-simply connected domains by inserting a special harmonic knot field in the dynamics of the magnetic potential. It is proved that the harmonic knot part of the vorticity

  11. Kidnapping small icy asteroids in Earth near encounter to harbour life and to deflect trajectory

    Science.gov (United States)

    Fargion, Daniele

    2016-07-01

    The inter-planetary flight for human being is under danger because of unscreened and lethal solar flare radioactive showers. The screening of the astronauts by huge superconducting magnetic fields is unrealistic by many reasons. On the contrary the ability to reach nearby icy asteroids, to harbour there a complete undergound room where ecological life systems are first set, this goal may offer a later natural and safe currier for future human stations and enterprise. The need to deflect such a small size (a few thousands tons objects) maybe achieved by micro nuclear engines able to dig the asteroid icy skin, to heat and propel the soil by a synchronous jet engine array, bending and driving it to any desired trajectories. The need for such a wide collection of icy asteroid stations, often in a robotic ibernated state, it will offer the safe help station, raft in the wide space sea, where to collect material or energy in long human planetary travels.

  12. Load-deflection characteristics of small-bore insulated-pipe clamps

    International Nuclear Information System (INIS)

    Severud, L.K.; Clark, G.L.

    1981-12-01

    The special insulated clamps used on both FFTF and CRBR piping utilize a Belleville spring arrangement to compensate for pipe thermal expansion. Analysis indicates that this produces a non-linear, directionally sensitive clamp spring rate. Since these spring rates influence the seismic response of a supported piping system, it was deemed necessary to evaluate them further by test. This has been accomplished for the FFTF clamps. A more standard insulated pipe clamp, which does not incorporate Belleville springs to accommodate thermal expansion, was also tested. This type clamp is simple in design, and economically attractive. It may have wide application prospects for use in LMFBR small bore auxiliary piping operating at temperatures below 427 0 C. Load deflection tests were conducted on 2.54 CM and 7.62 CM diameter samples of these commercial clamps

  13. Deflection Prediction of No-Fines Lightweight Concrete Wall Using Neural Network Caused Dynamic Loads

    Directory of Open Access Journals (Sweden)

    Ridho Bayuaji

    2018-04-01

    Full Text Available No-fines lightweight concrete wall with horizontal reinforcement refers to an alternative material for wall construction with an aim of improving the wall quality towards horizontal loads. This study is focused on artificial neural network (ANN application to predicting the deflection deformation caused by dynamic loads. The ANN method is able to capture the complex interactions among input/output variables in a system without any knowledge of interaction nature and without any explicit assumption to model form. This paper explains the existing data research, data selection and process of ANN modelling training process and validation. The results of this research show that the deformation can be predicted more accurately, simply and quickly due to the alternating horizontal loads.

  14. A Passive Flow-rate Regulator Using Pressure-dependent Autonomous Deflection of Parallel Membrane Valves

    International Nuclear Information System (INIS)

    Il, Doh; Cho, Young-Ho

    2009-01-01

    We present a passive flow-rate regulator, capable to compensate inlet pressure variation and to maintain a constant flow-rate for precise liquid control. Deflection of the parallel membrane valves in the passive flowrate regulator adjusts fluidic resistance according to inlet fluid pressure without any external energy. Compared to previous passive flow-rate regulators, the present device achieves precision flow regulation functions at the lower threshold compensation pressure of 20kPa with the simpler structure. In the experimental study, the fabricated device achieves the constant flow-rate of 6.09±0.32 μl/s over the inlet pressure range of 20∼50 kPa. The present flow-rate regulator having simple structure and lower compensation pressure level demonstrates potentials for use in integrated micropump systems

  15. Fuel assembly stress and deflection analysis for loss-of-coolant accident and seismic excitation

    International Nuclear Information System (INIS)

    DeMars, R.V.; Steinke, R.R.

    1975-01-01

    Babcock and Wilcox has evaluated the capability of the fuel assemblies to withstand the effects of a loss-of-coolant accident (LOCA) blowdown, the operational basis earthquake (OBE) and design basis earthquake (DBE), and the simultaneous occurrence of the DBE and LOCA. This method of analysis is applicable to all of B and W's nuclear steam system contracts that specify the skirt-supported pressure vessel. Loads during the saturated and subcooled phases of blowdown following a loss-of-coolant accident were calculated. The maximum loads on the fuel assemblies were found to be below allowable limits, and the maximum deflections of the fuel assemblies were found to be less than those that could prevent the insertion of control rods or the flow of coolant through the core. (U.S.)

  16. MEMS Tunneling Micro Thermometer Based onTip Deflection of Bimetallic Cantilever Beam

    Directory of Open Access Journals (Sweden)

    Samrand K. Nezhadian

    2007-10-01

    Full Text Available Micro-electro-mechanical (MEM technology promises to significantly reduce the size, weight and cost of a variety of sensor systems. In this article has been described a highly sensitive novel type of thermometer based on deflection of a “bimetallic” microbeam. The proposed thermometer converts the thermal changes of a cantilevered bimetallic beam of submillimeter size into an electrical signal through tunneling-current modulation. The governing thermo-mechanical equation of a bimetallic cantilever beam has been derived and solved analytically. The obtained results show that the proposed tunneling micro thermometer is very sensitive to temperature changes due to exponential increasing of tunneling current but because of small gap between metallic electrodes, measurable range of temperature changes is small.

  17. Magnetic helicity balance in the Sustained Spheromak Plasma Experiment

    International Nuclear Information System (INIS)

    Stallard, B.W.; Hooper, E.B.; Woodruff, S.; Bulmer, R.H.; Hill, D.N.; McLean, H.S.; Wood, R.D.

    2003-01-01

    The magnetic helicity balance between the helicity input injected by a magnetized coaxial gun, the rate-of-change in plasma helicity content, and helicity dissipation in electrode sheaths and Ohmic losses have been examined in the Sustained Spheromak Plasma Experiment (SSPX) [E. B. Hooper, L. D. Pearlstein, and R. H. Bulmer, Nucl. Fusion 39, 863 (1999)]. Helicity is treated as a flux function in the mean-field approximation, allowing separation of helicity drive and losses between closed and open field volumes. For nearly sustained spheromak plasmas with low fluctuations, helicity balance analysis implies a decreasing transport of helicity from the gun input into the spheromak core at higher spheromak electron temperature. Long pulse discharges with continuously increasing helicity and larger fluctuations show higher helicity coupling from the edge to the spheromak core. The magnitude of the sheath voltage drop, inferred from cathode heating and a current threshold dependence of the gun voltage, shows that sheath losses are important and reduce the helicity injection efficiency in SSPX

  18. Helical tomotherapy. Experiences of the first 150 patients in Heidelberg

    Energy Technology Data Exchange (ETDEWEB)

    Sterzing, F.; Schubert, K.; Sroka-Perez, G.; Kalz, J.; Debus, J.; Herfarth, K. [Dept. of Radiation Oncology, Univ. of Heidelberg (Germany)

    2008-01-15

    Background and purpose: helical tomotherapy was introduced into clinical routine at the Department of Radiation Oncology, University Hospital of Heidelberg, Germany, in July 2006. This report is intended to describe the experience with the first 150 patients treated with helical tomotherapy. Patient selection, time effort, handling of daily image guidance with megavoltage (MV) CT, and quality of radiation plans shall be assessed. Patients and methods: between July 2006 and May 2007, 150 patients were treated with helical tomotherapy in the University Hospital of Heidelberg. Mean age was 60 years with a minimum of 30 years and a maximum of 85 years. 79 of these patients received radiotherapy as a part of multimodal treatment pre- or postoperatively, 17 patients received treatment as a combined radiochemotherapy. 76% were treated with curative intent. Radiotherapy sites were central nervous system (n = 7), head and neck (n = 28), thoracic (n = 37), abdominal (n = 58) and skeletal system (n = 20). Most common tumor entities were prostate cancer (n = 28), breast cancer (n = 17), gastrointestinal tumors (n = 19), pharyngeal carcinoma (n = 14), lymphoma (n = 13), metastatic disease (bone n = 14, liver n = 6, lung n = 4, lymph node n = 2), sarcoma (n = 8), malignant pleural mesothelioma (n = 5), ovarian cancer treated with whole abdominal irradiation (n = 4), lung cancer (n = 3), skin malignancies (n = 3), chordoma (n = 2), meningioma (n = 2), one ependymoma and one medulloblastoma treated with craniospinal axis irradiation (n = 2), and others (n = 4). Nine patients were treated with single-fraction radiosurgery, nine with image-guided spinal reirradiation, and twelve patients were treated at multiple targets simultaneously. A pretreatment MV-CT scan was performed in 98.2% of the 3,026 fractions applied. After matching with the kilovoltage planning CT, corrections for translations and rotation around longitudinal axis (roll) were done. Results: mean time on table was 24

  19. A simulation methodology of spacer grid residual spring deflection for predictive and interpretative purposes

    International Nuclear Information System (INIS)

    Kim, K. T.; Kim, H. K.; Yoon, K. H.

    1994-01-01

    The in-reactor fuel rod support conditions against the fretting wear-induced damage can be evaluated by spacer grid residual spring deflection. In order to predict the spacer grid residual spring deflection as a function of burnup for various spring designs, a simulation methodology of spacer grid residual spring deflection has been developed and implemented in the GRIDFORCE program. The simulation methodology takes into account cladding creep rate, initial spring deflection, initial spring force, and spring force relaxation rate as the key parameters affecting the residual spring deflection. The simulation methodology developed in this study can be utilized as an effective tool in evaluating the capability of a newly designed spacer grid spring to prevent the fretting wear-induced damage

  20. Determination of angle of light deflection in higher-derivative gravity theories

    Science.gov (United States)

    Xu, Chenmei; Yang, Yisong

    2018-03-01

    Gravitational light deflection is known as one of three classical tests of general relativity and the angle of deflection may be computed explicitly using approximate or exact solutions describing the gravitational force generated from a point mass. In various generalized gravity theories, however, such explicit determination is often impossible due to the difficulty in obtaining an exact expression for the deflection angle. In this work, we present some highly effective globally convergent iterative methods to determine the angle of semiclassical gravitational deflection in higher- and infinite-derivative formalisms of quantum gravity theories. We also establish the universal properties that the deflection angle always stays below the classical Einstein angle and is a strictly decreasing function of the incident photon energy, in these formalisms.

  1. Experimental and Theoretical Deflections of Hybrid Composite Sandwich Panel under Four-point Bending Load

    Directory of Open Access Journals (Sweden)

    Jauhar Fajrin

    2017-03-01

    Full Text Available This paper presents a comparison of theoretical and experimental deflection of a hybrid sandwich panel under four-point bending load. The paper initially presents few basic equations developed under three-point load, followed by development of model under four-point bending load and a comparative analysis between theoretical and experimental results. It was found that the proposed model for predicting the deflection of hybrid sandwich panels provided fair agreement with the experimental values. Most of the sandwich panels showed theoretical deflection values higher than the experimental values, which is desirable in the design. It was also noticed that the introduction of intermediate layer does not contribute much to reduce the deflection of sandwich panel as the main contributor for the total deflection was the shear deformation of the core that mostly determined by the geometric of the samples and the thickness of the core.

  2. Study of the incident pion deflection in passing through atomic nucleus

    International Nuclear Information System (INIS)

    Strugalski, Z.; Pawlak, T.; Pluta, J.

    1982-01-01

    Pion-xenon nucleus collision events at 3.5 GeV/c momentum are studied in which the incident pion is deflected only, without particle production; the deflection is accompanied by emission of nucleons. The multiplicity of the protons emitted is a measure of the nuclear matter layer thickness passed by the pion. It can be concluded that: a) a definite simple relation exists between the pion deflection angle and the thickness of the nuclear matter layer traversed by this pion; b) the deflection angle of the incident pion increases in a definite manner with increasing the thickness of the nuclear matter layer traversed by this pion; c) the average kinetic energy, average longitudinal momentum and average transverse momentum of the protons emitted do not depend on the pion deflection angle

  3. Pitch dependence of longitudinal sampling and aliasing effects in multi-slice helical computed tomography (CT)

    International Nuclear Information System (INIS)

    La Riviere, Patrick J.; Pan Xiaochuan

    2002-01-01

    In this work, we investigate longitudinal sampling and aliasing effects in multi-slice helical CT. We demonstrate that longitudinal aliasing can be a significant, complicated, and potentially detrimental effect in multi-slice helical CT reconstructions. Multi-slice helical CT scans are generally undersampled longitudinally for all pitches of clinical interest, and the resulting aliasing effects are spatially variant. As in the single-slice case, aliasing is shown to be negligible at the isocentre for circularly symmetric objects due to a fortuitous aliasing cancellation phenomenon. However, away from the isocentre, aliasing effects can be significant, spatially variant, and highly pitch dependent. This implies that measures more sophisticated than isocentre slice sensitivity profiles are needed to characterize longitudinal properties of multi-slice helical CT systems. Such measures are particularly important in assessing the question of whether there are preferred pitches in helical CT. Previous analyses have generally focused only on isocentre sampling patterns, and our more global analysis leads to somewhat different conclusions than have been reached before, suggesting that pitches 3, 4, 5, and 6 are favourable, and that half-integer pitches are somewhat suboptimal. (author)

  4. Asymmetric fan beams (AFB) for improvement of the craniocaudal dose distribution in helical tomotherapy delivery

    International Nuclear Information System (INIS)

    Gladwish, Adam; Kron, Tomas; McNiven, Andrea; Bauman, Glenn; Van Dyk, Jake

    2004-01-01

    Helical tomotherapy (HT) is a novel radiotherapy technique that utilizes intensity modulated fan beams that deliver highly conformal dose distributions in a helical beam trajectory. The most significant limitation in dose delivery with a constant fan beam thickness (FBT) is the penumbra width of the dose distribution in the craniocaudal direction, which is equivalent to the FBT. We propose to employ a half-blocked fan beam at start and stop location to reduce the penumbra width by half. By opening the jaw slowly during the helical delivery until the desired FBT is achieved it is possible to create a sharper edge in the superior and inferior direction from the target. The technique was studied using a tomotherapy beam model implemented on a commercial treatment planning system (Theraplan Plus V3.0). It was demonstrated that the dose distribution delivered using a 25 mm fan beam can be improved significantly, to reduce the dose to normal structures located superiorly and inferiorly of the target. Dosimetry for this technique is straightforward down to a FBT of 15 mm and implementation should be simple as no changes in couch movement are required compared to a standard HT delivery. We conclude that the use of asymmetric collimated fan beams for the start and stop of the helical tomotherapeutic dose delivery has the potential of significantly improving the dose distribution in helical tomotherapy

  5. Structure determination of helical filaments by solid-state NMR spectroscopy

    Science.gov (United States)

    Ahmed, Mumdooh; Spehr, Johannes; König, Renate; Lünsdorf, Heinrich; Rand, Ulfert; Lührs, Thorsten; Ritter, Christiane

    2016-01-01

    The controlled formation of filamentous protein complexes plays a crucial role in many biological systems and represents an emerging paradigm in signal transduction. The mitochondrial antiviral signaling protein (MAVS) is a central signal transduction hub in innate immunity that is activated by a receptor-induced conversion into helical superstructures (filaments) assembled from its globular caspase activation and recruitment domain. Solid-state NMR (ssNMR) spectroscopy has become one of the most powerful techniques for atomic resolution structures of protein fibrils. However, for helical filaments, the determination of the correct symmetry parameters has remained a significant hurdle for any structural technique and could thus far not be precisely derived from ssNMR data. Here, we solved the atomic resolution structure of helical MAVSCARD filaments exclusively from ssNMR data. We present a generally applicable approach that systematically explores the helical symmetry space by efficient modeling of the helical structure restrained by interprotomer ssNMR distance restraints. Together with classical automated NMR structure calculation, this allowed us to faithfully determine the symmetry that defines the entire assembly. To validate our structure, we probed the protomer arrangement by solvent paramagnetic resonance enhancement, analysis of chemical shift differences relative to the solution NMR structure of the monomer, and mutagenesis. We provide detailed information on the atomic contacts that determine filament stability and describe mechanistic details on the formation of signaling-competent MAVS filaments from inactive monomers. PMID:26733681

  6. Helical CT of congenital ossicular anomalies

    International Nuclear Information System (INIS)

    Osada, Hisato; Machida, Kikuo; Honda, Norinari

    2001-01-01

    Since January 1996 to December 2000, 26 cases of congenital ossicular anomaly could be diagnosed with helical CT. All cases were unilateral. In 8 patients with malformation of the external ear, CT showed malleoincudal fixation (n=5), malleoincudal fixation and deformed incuts long process (n=1), deformed incus long process (n=1), and partial fusion of malleus neck and incus long process (n=1). In 18 patients with normal external ear, CT showed defect of the incus long process (n=5), defect of both the incus long process and stapes superstructure (n=8, 2 patients with congenital cholesteatoma, 1 with hypoplastic oval window), defect of the stapes superstructure (n=2, 1 patient with oval window absence), defect of the malleus manubrium (n=1), ossification of the stampede's tendon (n=1), and monopod stapes (n=1). Helical CT can evaluate the auditory ossicular chain in detail and is useful for diagnosing congenital ossicular anomaly. (author)

  7. Weaving Knotted Vector Fields with Tunable Helicity.

    Science.gov (United States)

    Kedia, Hridesh; Foster, David; Dennis, Mark R; Irvine, William T M

    2016-12-30

    We present a general construction of divergence-free knotted vector fields from complex scalar fields, whose closed field lines encode many kinds of knots and links, including torus knots, their cables, the figure-8 knot, and its generalizations. As finite-energy physical fields, they represent initial states for fields such as the magnetic field in a plasma, or the vorticity field in a fluid. We give a systematic procedure for calculating the vector potential, starting from complex scalar functions with knotted zero filaments, thus enabling an explicit computation of the helicity of these knotted fields. The construction can be used to generate isolated knotted flux tubes, filled by knots encoded in the lines of the vector field. Lastly, we give examples of manifestly knotted vector fields with vanishing helicity. Our results provide building blocks for analytical models and simulations alike.

  8. SUPERCONDUCTING HELICAL SNAKE MAGNETS: CONSTRUCTION AND MEASUREMENTS

    International Nuclear Information System (INIS)

    Mackay, W.W.; Anerella, M.; Courant, E.

    1999-01-01

    In order to collide polarized protons, the RHIC project will have two snakes in each ring and four rotators around each of two interaction regions. Two snakes on opposite sides of each ring can minimize depolarization during acceleration by keeping the spin tune at a half. Since the spin direction is normally along the vertical direction in a flat ring, spin rotators must be used around an interaction point to have longitudinal polarization in a collider experiment. Each snake or rotator will be composed of four helical dipoles to provide the required rotation of spin with minimal transverse orbit excursions in a compact length of 10m. The basic helical dipole is a superconducting magnet producing a transverse dipole field which is twisted about the magnet axis through 360 o in a length of 2.4 m. The design and construction of the magnets is described in this paper

  9. Three-dimensional printing of freeform helical microstructures: a review.

    Science.gov (United States)

    Farahani, R D; Chizari, K; Therriault, D

    2014-09-21

    Three-dimensional (3D) printing is a fabrication method that enables creation of structures from digital models. Among the different structures fabricated by 3D printing methods, helical microstructures attracted the attention of the researchers due to their potential in different fields such as MEMS, lab-on-a-chip systems, microelectronics and telecommunications. Here we review different types of 3D printing methods capable of fabricating 3D freeform helical microstructures. The techniques including two more common microfabrication methods (i.e., focused ion beam chemical vapour deposition and microstereolithography) and also five methods based on computer-controlled robotic direct deposition of ink filament (i.e., fused deposition modeling, meniscus-confined electrodeposition, conformal printing on a rotating mandrel, UV-assisted and solvent-cast 3D printings) and their advantages and disadvantages regarding their utilization for the fabrication of helical microstructures are discussed. Focused ion beam chemical vapour deposition and microstereolithography techniques enable the fabrication of very precise shapes with a resolution down to ∼100 nm. However, these techniques may have material constraints (e.g., low viscosity) and/or may need special process conditions (e.g., vacuum chamber) and expensive equipment. The five other techniques based on robotic extrusion of materials through a nozzle are relatively cost-effective, however show lower resolution and less precise features. The popular fused deposition modeling method offers a wide variety of printable materials but the helical microstructures manufactured featured a less precise geometry compared to the other printing methods discussed in this review. The UV-assisted and the solvent-cast 3D printing methods both demonstrated high performance for the printing of 3D freeform structures such as the helix shape. However, the compatible materials used in these methods were limited to UV-curable polymers and

  10. Study of Pelvicaliceal Anatomy by Helical Computerized Tomography

    International Nuclear Information System (INIS)

    Al-Qahtani, Fahd N.; Ali, Gaber A.; Kamal, Baher A.; Taha, Saud A.

    2003-01-01

    To evaluate the role of 3-dimensional images produced by computerized tomography (CT), using intravenous contrast, to study pelvicaliceal anatomy.This might be of help in endourological procedure. The study was conducted in the King Fahd Hospital of the University, King Faisal University. Dammam,Kingdom of Saudi Arabia. The study took place from July 2002 through to October 2002 .Helical CT was carried for patients who were investigated using excretory urography for any reason. A CT was carried out to the kidneys only within 10 minutes ( between 5 and 15 minute films of excretory urography).Images were reprocessed by 3-dimension construction after subtracting all structures except for the palvicaliceal system. Thity-six normal kidneys were studied. The upper pole was drained by a single caliceal infundibulum in all 36(100%) kidneys.the middle segement of the kidney was drained by 2 infundibula in 32 (89%) kidneys. Four (11%) kidneys have no middle caliceal infudibula. The lower pole was drained by 2 caliceal infundibula in 23 (64%) and a single infundibulum in 13 (36%) kidneys. The minor calices draining each renal segment were seen clearly. Three-dimensional images derived by helical CT are feasible for evaluating the anatomy of palvicaliceal system,and, can be of help in endourological procedures. (author)/

  11. Dosimetric verification of helical tomotherapy for total scalp irradiation

    International Nuclear Information System (INIS)

    Hardcastle, Nicholas; Soisson, Emilie; Metcalfe, Peter; Rosenfeld, Anatoly B.; Tome, Wolfgang A.

    2008-01-01

    Total scalp irradiation is a treatment technique used for a variety of superficial malignancies. Helical tomotherapy is an effective technique used for total scalp irradiation. Recent published work has shown the TomoTherapy planning system to overestimate the superficial dose. In this study, the superficial doses for a helical tomotherapy total scalp irradiation have been measured on an anthropomorphic phantom using radiochromic and radiographic film as well as a new skin dosimeter, the MOSkin. The superficial dose was found to be accurately calculated by the TomoTherapy planning system. This is in contrast to recent reports, probably due to a combination of the smaller dose grid resolution used in planning and this particular treatment primarily consisting of beamlets tangential to the scalp. The superficial dose was found to increase from 33.6 to 41.2 Gy and 36.0 to 42.0 Gy over the first 2 mm depth in the phantom in selected regions of the PTV, measured with radiochromic film. The prescription dose was 40 Gy. The superficial dose was at the prescription dose or higher in some regions due to the bolus effect of the thermoplastic head mask and the head rest used to aid treatment setup. It is suggested that to achieve the prescription dose at the surface (≤2 mm depth) bolus or a custom thermoplastic helmet is used.

  12. Buoyant Helical Twin-Axial Wire Antenna

    Science.gov (United States)

    2016-11-15

    February 2017 The below identified patent application is available for licensing. Requests for information should be addressed to...300169 1 of 9 BUOYANT HELICAL TWIN-AXIAL WIRE ANTENNA CROSS REFERENCE TO OTHER PATENT APPLICATIONS [0001] This application is a divisional...application and claims the benefit of the filing date of United States Patent Application No. 14/280,889; filed on May 19, 2014; and entitled “Twin-Axial

  13. Molecular Dynamics with Helical Periodic Boundary Conditions

    Czech Academy of Sciences Publication Activity Database

    Kessler, Jiří; Bouř, Petr

    2014-01-01

    Roč. 35, č. 21 (2014), s. 1552-1559 ISSN 0192-8651 R&D Projects: GA ČR GAP208/11/0105; GA MŠk(CZ) LH11033 Grant - others:GA AV ČR(CZ) M200551205; GA MŠk(CZ) LM2010005 Institutional support: RVO:61388963 Keywords : periodic boundary conditions * helical symmetry * molecular dynamics * protein structure * amyloid fibrils Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.589, year: 2014

  14. Simplification of the helical TEN2 laser

    Science.gov (United States)

    Krahn, K.-H.

    1980-04-01

    The observation that the helical TEN2 laser can effectively be simplified by giving up the use of decoupling elements as well as by abolishing the segmentation of the electrode structure is examined. Although, as a consequence of this simplification, the operating pressure range was slightly decreased, the output power could be improved by roughly 30%, a result which is attributed to the new electrode geometry exhibiting lower inductance and lower damping losses.

  15. Field of a helical Siberian Snake

    Energy Technology Data Exchange (ETDEWEB)

    Luccio, A. [Brookhaven National Lab., Upton, NY (United States)

    1995-02-01

    To preserve the spin polarization of a beam of high energy protons in a circular accelerator, magnets with periodic magnetic field, called Siberian Snakes are being used. Recently, it was proposed to build Siberian Snakes with superconducting helical dipoles. In a helical, or twisted dipole, the magnetic field is perpendicular to the axis of the helix and rotates around it as one proceeds along the magnet. In an engineering study of a 4 Tesla helical snake, the coil geometry is derived, by twisting, from the geometry of a cosine superconducting dipole. While waiting for magnetic measurement data on such a prototype, an analytical expression for the field of the helice is important, to calculate the particle trajectories and the spin precession in the helix. This model will also allow to determine the optical characteristics of the snake, as an insertion in the lattice of the accelerator. In particular, one can calculate the integrated multipoles through the magnet and the equivalent transfer matrix. An expression for the field in the helix body, i.e., excluding the fringe field was given in a classical paper. An alternate expression can be found by elaborating on the treatment of the field of a transverse wiggler obtained under the rather general conditions that the variables are separable. This expression exactly satisfies Maxwell`s div and curl equations for a stationary field, {del} {center_dot} B = 0, {del} x B = 0. This approach is useful in that it will allow one to use much of the work already done on the problem of inserting wigglers and undulators in the lattice of a circular accelerator.

  16. Turbulence spectra, transport, and E × B flows in helical plasmas

    International Nuclear Information System (INIS)

    Watanabe, T.-H.; Nunami, M.; Sugama, H.; Satake, S.; Matsuoka, S.; Ishizawa, A.; Tanaka, K.; Maeyama, Shinya

    2012-11-01

    Gyrokinetic simulation of ion temperature gradient turbulence and zonal flows for helical plasmas has been validated against the Large Helical Device experiments with high ion temperature, where a reduced modeling of ion heat transport is also considered. It is confirmed by the entropy transfer analysis that the turbulence spectrum elongated in the radial wavenumber space is associated with successive interactions with zonal flows. A novel multi-scale simulation for turbulence and zonal flows in poloidally-rotating helical plasmas has demonstrated strong zonal flow generation by turbulence, which implies that turbulent transport processes in non-axisymmetric systems are coupled to neoclassical transport through the macroscopic E × B flows determined by the ambipolarty condition for neoclassical particle fluxes. (author)

  17. Helical waves in easy-plane antiferromagnets

    Science.gov (United States)

    Semenov, Yuriy G.; Li, Xi-Lai; Xu, Xinyi; Kim, Ki Wook

    2017-12-01

    Effective spin torques can generate the Néel vector oscillations in antiferromagnets (AFMs). Here, it is theoretically shown that these torques applied at one end of a normal AFM strip can excite a helical type of spin wave in the strip whose properties are drastically different from characteristic spin waves. An analysis based on both a Néel vector dynamical equation and the micromagnetic simulation identifies the direction of magnetic anisotropy and the damping factor as the two key parameters determining the dynamics. Helical wave propagation requires the hard axis of the easy-plane AFM to be aligned with the traveling direction, while the damping limits its spatial extent. If the damping is neglected, the calculation leads to a uniform periodic domain wall structure. On the other hand, finite damping decelerates the helical wave rotation around the hard axis, ultimately causing stoppage of its propagation along the strip. With the group velocity staying close to spin-wave velocity at the wave front, the wavelength becomes correspondingly longer away from the excitation point. In a sufficiently short strip, a steady-state oscillation can be established whose frequency is controlled by the waveguide length as well as the excitation energy or torque.

  18. Helical CT in acute lower gastrointestinal bleeding

    International Nuclear Information System (INIS)

    Ernst, Olivier; Leroy, Christophe; Sergent, Geraldine; Bulois, Philippe; Saint-Drenant, Sophie; Paris, Jean-Claude

    2003-01-01

    The purpose of this study was to assess the usefulness of helical CT in depicting the location of acute lower gastrointestinal bleeding. A three-phase helical CT of the abdomen was performed in 24 patients referred for acute lower gastrointestinal bleeding. The diagnosis of the bleeding site was established by CT when there was at least one of the following criteria: spontaneous hyperdensity of the peribowel fat; contrast enhancement of the bowel wall; vascular extravasation of the contrast medium; thickening of the bowel wall; polyp or tumor; or vascular dilation. Diverticula alone were not enough to locate the bleeding site. The results of CT were compared with the diagnosis obtained by colonoscopy, enteroscopy, or surgery. A definite diagnosis was made in 19 patients. The bleeding site was located in the small bowel in 5 patients and the colon in 14 patients. The CT correctly located 4 small bowel hemorrhages and 11 colonic hemorrhages. Diagnosis of the primary lesion responsible for the bleeding was made in 10 patients. Our results suggest that helical CT could be a good diagnostic tool in acute lower gastrointestinal bleeding to help the physician to diagnose the bleeding site. (orig.)

  19. Total scalp irradiation using helical tomotherapy

    International Nuclear Information System (INIS)

    Orton, Nigel; Jaradat, Hazim; Welsh, James; Tome, Wolfgang

    2005-01-01

    Homogeneous irradiation of the scalp poses technical and dosimetric challenges due to the extensive, superficial, curved treatment volume. Conventional treatments on a linear accelerator use multiple matched electron fields or a combination of electron and photon fields. Problems with these techniques include dose heterogeneity in the target due to varying source-to-skin distance (SSD) and angle of beam incidence, significant dose to the brain, and the potential for overdose or underdose at match lines between the fields. Linac-based intensity-modulated radiation therapy (IMRT) plans have similar problems. This work presents treatment plans for total scalp irradiation on a helical tomotherapy machine. Helical tomotherapy is well-suited for scalp irradiation because it has the ability to deliver beamlets that are tangential to the scalp at all points. Helical tomotherapy also avoids problems associated with field matching and use of more than one modality. Tomotherapy treatment plans were generated and are compared to plans for treatment of the same patient on a linac. The resulting tomotherapy plans show more homogeneous target dose and improved critical structure dose when compared to state-of-the-art linac techniques. Target equivalent uniform dose (EUD) for the best tomotherapy plan was slightly higher than for the linac plan, while the volume of brain tissue receiving over 30 Gy was reduced by two thirds. Furthermore, the tomotherapy plan can be more reliably delivered than linac treatments, because the patient is aligned prior to each treatment based on megavoltage computed tomography (MVCT)

  20. THE EFFECTS OF SPATIAL SMOOTHING ON SOLAR MAGNETIC HELICITY PARAMETERS AND THE HEMISPHERIC HELICITY SIGN RULE

    Energy Technology Data Exchange (ETDEWEB)

    Ocker, Stella Koch [Department of Physics, Oberlin College, Oberlin, OH 44074 (United States); Petrie, Gordon, E-mail: socker@oberlin.edu, E-mail: gpetrie@nso.edu [National Solar Observatory, Boulder, CO 80303 (United States)

    2016-12-01

    The hemispheric preference for negative/positive helicity to occur in the northern/southern solar hemisphere provides clues to the causes of twisted, flaring magnetic fields. Previous studies on the hemisphere rule may have been affected by seeing from atmospheric turbulence. Using Hinode /SOT-SP data spanning 2006–2013, we studied the effects of two spatial smoothing tests that imitate atmospheric seeing: noise reduction by ignoring pixel values weaker than the estimated noise threshold, and Gaussian spatial smoothing. We studied in detail the effects of atmospheric seeing on the helicity distributions across various field strengths for active regions (ARs) NOAA 11158 and NOAA 11243, in addition to studying the average helicities of 179 ARs with and without smoothing. We found that, rather than changing trends in the helicity distributions, spatial smoothing modified existing trends by reducing random noise and by regressing outliers toward the mean, or removing them altogether. Furthermore, the average helicity parameter values of the 179 ARs did not conform to the hemisphere rule: independent of smoothing, the weak-vertical-field values tended to be negative in both hemispheres, and the strong-vertical-field values tended to be positive, especially in the south. We conclude that spatial smoothing does not significantly affect the overall statistics for space-based data, and thus seeing from atmospheric turbulence seems not to have significantly affected previous studies’ ground-based results on the hemisphere rule.