WorldWideScience

Sample records for strong flux pinning

  1. Flux pinning characteristics of YBCO coated conductor

    International Nuclear Information System (INIS)

    Matsushita, T.; Watanabe, T.; Fukumoto, Y.; Yamauchi, K.; Kiuchi, M.; Otabe, E.S.; Kiss, T.; Watanabe, T.; Miyata, S.; Ibi, A.; Muroga, T.; Yamada, Y.; Shiohara, Y.

    2005-01-01

    Flux pinning properties of PLD-processed YBCO coated conductors deposited on IBAD substrate are investigated. The thickness of YBCO layer is changed in the range of 0.27-1.0 μm. The thickness dependence of critical current density, n-value and irreversibility field are measured in a wide range of magnetic field. The results are compared with the theoretical flux creep-flow model. It is found that these pinning properties are strongly influenced by the thickness as well as the pinning strength. Optimum condition for high field application of this superconductor is discussed

  2. Matching of the Flux Lattice to Geometrically Frustrated Pinning Arrays

    Science.gov (United States)

    Trastoy, J.; Bernard, R.; Briatico, J.; Villegas, J. E.; Lesueur, J.; Ulysse, C.; Faini, G.

    2013-03-01

    We use vortex dynamics on artificial nanoscale energy landscapes as a model to experimentally investigate a problem inspired by ``spin ice'' systems. In particular, we study the matching of the flux lattice to pinning arrays in which the geometrical frustration is expected to impede a unique stable vortex configuration and to promote metastability. This is done with YBCO films in which the nanoscale vortex energy landscape is fabricated via masked ion irradiation. Surprisingly, we found that minimal changes in the distance between pinning sites lead to the suppression of some of the magneto-resistance matching effects, that is, for certain well-defined vortex densities. This effect strongly depends on the temperature. We argue that this behavior can be explained considering the arrays' geometrical frustration and the thermally activated reconfiguration of the vortex lattice between isoenergetic states. Work supported by the French ANR via SUPERHYRBIDS-II and ``MASTHER,'' and the Galician Fundacion Barrie

  3. Self-organized critical behavior in pinned flux lattices

    International Nuclear Information System (INIS)

    Pla, O.; Nori, F.

    1991-01-01

    We study the response of pinned fluxed lattices, under small perturbations in the driving force, below and close to the pinning-depinning transition. For driving Lorentz forces below F c (the depinning force at which the whole flux lattice slides), the system has instabilities against small force increases, with a power-law distribution characteristic of self-organized criticality. Specifically, D(d)∼d -1,3 , where d is the displacement of a flux line after a very small force increase. We also study the initial stages of the motion of the lattice once the driving force overcomes the pinning forces

  4. Close Proximity Robotic Maneuvering through Flux Pinning Manipulation

    Data.gov (United States)

    National Aeronautics and Space Administration — Non-contacting actuation technology like flux pinning has never been demonstrated in space. The development of a nonphysical joint is critical for maneuvers such as...

  5. Flux-Vortex Pinning and Neutron Star Evolution

    Indian Academy of Sciences (India)

    M. Ali Alpar

    Flux-Vortex Pinning and Neutron Star Evolution. M. ALI ALPAR. Faculty of Engineering and Natural Sciences, Sabancı University, 34956, Istanbul, Turkey. E-mail: alpar@sabanciuniv.edu. MS received 22 May 2017; accepted 24 July 2017; published online 12 September 2017. Abstract. G. Srinivasan et al. (1990) proposed ...

  6. Experimental study of flux pinning in NbN films and multilayers: Ultimate limits on critical currents in superconductors

    International Nuclear Information System (INIS)

    Gray, K.E.; Kampwirth, R.T.; Capone, D.W. II; Murduck, J.M.

    1988-08-01

    A flux pinning model is presented which predicts the maximum critical current density attainable in superconductors. That such a limit must exist comes from the realization that flux pinning is strongest in regions of weak superconductivity, but these regions cannot carry a large supercurrent. Since the same regions within the superconductor cannot be used for both pinning and supercurrent conductions, there must be an optimum mix, leading to a maximum J/sub c/. Measurements on films and multilayers of NbN have verified many details of the model including anisotropy effects and a strong reduction in J/sub c/ for defect spacings smaller than the flux core diameter. In an optimized multilayer the pinning force reached /approximately/22% of the theoretical maximum. The implications of these results on the practical applications of NbN films and on the maximum critical current density in the new high temperature superconductors are also discussed. 24 refs., 4 figs

  7. Fast Flux Test Facility metal fuel pin fabrication

    International Nuclear Information System (INIS)

    Benecke, M.W.; Dittmer, J.O.; Feigenbutz, L.V.

    1989-05-01

    A new initiative to develop, irradiate, and qualify a binary uranium/zirconium metal fuel system in the Fast Flux Test Facility (FFTF) has been implemented by the Westinghouse Hanford Company for the US Department of Energy. Metal fuel test assemblies have been designed and fabricated and are now being irradiated in FFTF to provide the data needed to support the potential use of binary fuels in FFTF and other liquid metal reactors. These development efforts support licensing activities for metal fuel use in near-term advanced liquid metal reactors. New metal fuel pin design features, fabrication development, and fabrication processes for three metal fuel tests will be described and their irradiation status reported in this paper. 11 figs

  8. Flux pinning by voids in surface-oxidized superconducting niobium and vanadium

    International Nuclear Information System (INIS)

    Meij, G.P. van der.

    1984-03-01

    The volume pinning force in several niobium and vanadium samples with voids is determined at various temperatures. Reasonable agreement is found with the collective pinning theory of Larkin and Ovchinnikov above the field of maximum pinning, if the flux line lattice is assumed to be amorphous in this region and if the elementary pinning force is calculated from the quasi-classical theory of Thuneberg, Kurkijaervi, and Rainer. Also some history and relaxation effects are studied in an alternating field. A qualitative explanation is given in terms of flux line dislocations, which reduce the shear strength of the flux line lattice. (Auth.)

  9. Flux flow, pinning, and resistive behavior in superconducting networks

    International Nuclear Information System (INIS)

    Teitel, S.

    1991-10-01

    We have studied the behavior of fluctuation effects in superconducting systems using numerical simulations of XY and Coulomb gas models. Flux flow resistance in two dimensional Josephson junction arrays has been calculated, and related to correlations in vortex structure. Randomness has been introduced, and its effects on the superconducting transition, and vortex mobility, have been studied. We find that randomness destroys phase coherence, yet the randomness induced pinning reduces flux flow resistance at low temperatures. Vortex line fluctuations in high temperature superconductors have been studied using a three dimensional XY model. We have considered the melting of the vortex line lattice, and the entanglement and cutting of vortex lines in the vortex line liquid phase. Vortex line entangling and cutting appear to occur on the same length scales in the liquid phase. The vortex structure function has been calculated and from it, elastic properties of the vortex line liquid have been inferred. The two dimensional classical Coulomb gas, where charges map onto vortices in the superconducting system, has been simulated. The melting transitions of ordered charge (vortex) lattices have been studied, and we find evidence that these transitions do not have the critical behavior expected from standard symmetry analysis

  10. Enhanced Flux Pinning in Laser Ablated YBCO:BaTiO3 Nanocomposite Thin Film

    Science.gov (United States)

    Jha, Alok K.; Khare, Neeraj; Pinto, R.

    2011-07-01

    The effect of incorporation of BaTiO3 (BTO) nanoparticles on the flux pinning properties of laser deposited YBCO:BTO thin films has been studied. Substantial increase in critical current density (JC) and pinning force density of the nanocomposite thin films was observed. The study of temperature and field dependence of JC of YBCO and YBCO:BTO thin films indicates similar type of pinning. The lattice mismatch between YBCO and BTO seems to introduce more defects resulting in improved flux pinning properties.

  11. Flux pinning in bronze-processed Nb3Sn wires

    International Nuclear Information System (INIS)

    Suenaga, M.; Welch, D.O.

    1980-01-01

    The scaling law derived by Kramer for magnetic flux pinning in high magnetic fields was examined for its applicability to the magnetic field dependence of critical-current densities in the bronze processed monofilamentary Nb 3 Sn wires. From this it was concluded that: (1) its prediction for the form of the dependence of critical current on magnetic field and grain size [/J vector /sub c/ x H vector/ approx. h/sup 1/2/(1-h) 2 (1-a 0 √rho) -2 ] was found to be very good in most cases including wires with very small Nb 3 Sn grains (approx. 400 A). It was found very useful in comparison of J/sub c/ for different wires and in extrapolating to obtain H/sub c2/ for these wires. (2) However, it could not account consistently for the anisotropy in critical current of a tape which was measured with H applied perpendicular and parallel to the tape face. (3) The values of kappa 1 which were determined with the scaling law were too small by a factor of 2 to 3, and the trend in the variation with heat-treating time was opposite to that which is reasonably to be expected. That the behavior of kappa 1 is thus seriously in contradiction with the expected behavior for Nb 3 Sn suggests basic faults in the derivation of the scaling equation for critical currents at high magnetic fields

  12. Flux pinning property in a single crystal NdBa2Cu3Oy superconductor

    International Nuclear Information System (INIS)

    Hasan, M.N.; Kurokawa, T.; Kiuchi, M.; Otabe, E.S.; Matsushita, T.; Chikumoto, N.; Machi, T.; Muralidhar, M.; Murakami, M.

    2005-01-01

    The critical current density J c and the apparent pinning potential U 0 * in a single crystal NdBa 2 Cu 3 O y superconductor which shows a broad peak effect are investigated by measuring a DC magnetization and its relaxation. The field-induced pinning mechanism does not explain the temperature dependence of peak field B p and dip field B d . The experimental results of J c and U 0 * are compared with the theoretical analysis based on the flux creep-flow model, taking the distribution of the flux pinning strength into account. The number of flux lines in the flux bundle (g 2 ), the most probable value of pinning strength (A m ) and distribution width (σ 2 ) are determined so that a good fit is obtained between the experimental and theoretical results. The behavior of these parameters is discussed in correspondence to the disorder transition of flux lines

  13. Stick-Jump (SJ) Evaporation of Strongly Pinned Nanoliter Volume Sessile Water Droplets on Quick Drying, Micropatterned Surfaces.

    Science.gov (United States)

    Debuisson, Damien; Merlen, Alain; Senez, Vincent; Arscott, Steve

    2016-03-22

    We present an experimental study of stick-jump (SJ) evaporation of strongly pinned nanoliter volume sessile water droplets drying on micropatterned surfaces. The evaporation is studied on surfaces composed of photolithographically micropatterned negative photoresist (SU-8). The micropatterning of the SU-8 enables circular, smooth, trough-like features to be formed which causes a very strong pinning of the three phase (liquid-vapor-solid) contact line of an evaporating droplet. This is ideal for studying SJ evaporation as it contains sequential constant contact radius (CCR) evaporation phases during droplet evaporation. The evaporation was studied in nonconfined conditions, and forced convection was not used. Micropatterned concentric circles were defined having an initial radius of 1000 μm decreasing by a spacing ranging from 500 to 50 μm. The droplet evaporates, successively pinning and depinning from circle to circle. For each pinning radius, the droplet contact angle and volume are observed to decrease quasi-linearly with time. The experimental average evaporation rates were found to decrease with decreasing pining radii. In contrast, the experimental average evaporation flux is found to increase with decreasing droplet radii. The data also demonstrate the influence of the initial contact angle on evaporation rate and flux. The data indicate that the total evaporation time of a droplet depends on the specific micropattern spacing and that the total evaporation time on micropatterned surfaces is always less than on flat, homogeneous surfaces. Although the surface patterning is observed to have little effect on the average droplet flux-indicating that the underlying evaporation physics is not significantly changed by the patterning-the total evaporation time is considerably modified by patterning, up to a factor or almost 2 compared to evaporation on a flat, homogeneous surface. The closely spaced concentric circle pinning maintains a large droplet radius and

  14. Flux pinning behaviors of Ti and C co-doped MgB{sub 2} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Y.; Zhao, D.; Shen, T.M.; Li, G.; Zhang, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Feng, Y. [Northwest Institute for Nonferrous Metal Research, P.O. Box 51, Xian, Shaanxi 710016 (China); Western Superconductivity Technology Company, Xian (China); Cheng, C.H. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney 2052, NSW (Australia); Zhang, Y.P. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhao, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney 2052, NSW (Australia)], E-mail: yzhao@swjtu.edu.cn

    2008-09-15

    Flux pinning behavior of carbon and titanium concurrently doped MgB{sub 2} alloys has been studied by ac susceptibility and dc magnetization measurements. It is found that critical current density and irreversibility field of MgB{sub 2} have been significantly improved by doping C and Ti concurrently, sharply contrasted to the situation of C-only-doped or Ti-only-doped MgB{sub 2} samples. AC susceptibility measurement reveals that the dependence of the pinning potential on the dc applied field of Mg{sub 0.95}Ti{sub 0.05}B{sub 1.95}C{sub 0.05} has been determined to be U(B{sub dc}){proportional_to}B{sub dc}{sup -1} compared to that of MgB{sub 2}U(B{sub dc}){proportional_to}B{sub dc}{sup -1.5}. As to the U(J) behavior, a relationship of U(J) {proportional_to} J{sup -0.17} is found fitting well for Mg{sub 0.95}Ti{sub 0.05}B{sub 1.95}C{sub 0.05} with respect to U(J) {proportional_to} J{sup -0.21} for MgB{sub 2}. All the results reveal a strong enhancement of the high field pinning potential in C and Ti co-doped MgB{sub 2}.

  15. Flux pinning and flux flow studies in superconductors using flux flow noise techniques. Progress report, April 1, 1976--December 17, 1976

    International Nuclear Information System (INIS)

    Joiner, W.C.H.

    1976-12-01

    Measurements of flux flow noise power spectra have been combined with critical current measurements and measurements of current-voltage characteristics to study flux flow and local pinning interactions effective during flux flow. A model of flux flow noise generation in the presence of local pinning interactions is developed and applied to situations where pinning is dominated by: (1) grain boundaries, (2) normal metal precipitates in a superconducting matrix, (3) gross deformation producing a critical current peak effect, and (4) surface grooves imposed on a sample surface. In the case of pinning caused by normal metal precipitates in a superconducting matrix, unusual training and hysterisis effects are observed in the flux flow characteristics. The greater sensitivity of noise spectra, as compared with bulk critical current measurements, in obtaining a detailed picture of flux flow is emphasized

  16. Flux pinning and flux flow studies in superconductors using flux flow noise techniques. Progress report, April 1-December 30, 1979

    International Nuclear Information System (INIS)

    Joiner, W.C.H.

    1979-12-01

    Flux flow noise power spectra were investigated, and information obtained through such spectra is applied to describe flux flow and pinning in situations where volume pinning force data is also available. In one case, the application of noise data to PB 80 In 20 samples after recovery and after high temperature annealing is discussed. This work is consistent with a recent model for flux flow noise generation. In the second case we discuss experiments designed to change the fluxoid transit path length, which according to the model should affect both the noise amplitude and the parameter α specifying the longest subpulse times in terms of the average transit time, tau/sub c/. Transient flux flow voltages when a current is switched on after field cycling a Pb 60 In 40 sample have been discovered. Noise spectra have been measured during the transient. These observations are discussed along with a simple model which fits the data. A surprising result is that the transient decay times increase with the applied current. Other characteristics of Pb 60 In 40 after cold working are also discussed

  17. Control of Flux Pinning in MOD YBCO Coated Conductor

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W. [American Superconductor Corporation, Westborough, MA; Huang, Y. [American Superconductor Corporation, Westborough, MA; Li, X. [American Superconductor Corporation, Westborough, MA; Kodenkandath, Thomas [American Superconductor Corporation, Westborough, MA; Rupich, Marty [American Superconductor Corporation, Westborough, MA; Schoop, U. [American Superconductor Corporation, Westborough, MA; Verebelyi, D. T. [American Superconductor Corporation, Westborough, MA; Thieme, C. L. H. [American Superconductor Corporation, Westborough, MA; Siegal, E. E. [American Superconductor Corporation, Westborough, MA; Holesinger, T. G. [Los Alamos National Laboratory (LANL); Maiorov, B. [Los Alamos National Laboratory (LANL); Miller, D. J. [Argonne National Laboratory (ANL); Maroni, V. A. [Argonne National Laboratory (ANL); Goyal, Amit [ORNL; Specht, Eliot D [ORNL; Paranthaman, Mariappan Parans [ORNL

    2007-01-01

    Two different types of defect structures have been identified to be responsible for the enhanced pinning in metal organic deposited YBCO films. Rare earth additions result in the formation of nanodots in the YBCO matrix, which form uncorrelated pinning centers, increasing pinning in all magnetic field orientations. 124-type intergrowths, which form as laminar structures parallel to the ab-plane, are responsible for the large current enhancement when the magnetic field is oriented in the ab-plane. TEM studies showed that the intergrowths emanate from cuprous containing secondary phase particles, whose density is partially controlled by the rare earth doping level. Critical process parameters have been identified to control this phase formation, and therefore, control the f 24 intergrowth formation. This work has shown that through process control and proper conductor design, either by adjusting the composition or by multiple coatings of different functional layers, the desired angular dependence can be achieved.

  18. Control of flux pinning in MOD YBCO coated conductor.

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W.; Huang, Y.; Li, X.; Kodenkandath, T.; Rupich, M. W.; Schoop, U.; Verebelyi, D. T.; Thieme, C. L. H.; Siegal, E.; Holesinger, T. G.; Maiorov, B.; Civale, L.; Miller, D. J.; Maroni, V. A.; Li, J.; Martin, P. M.; Specht, E. D.; Goyal, A.; Paranthaman, M. P.; American Superconductor Corp.; LANL; ORNL

    2007-06-01

    NTwo different types of defect structures have been identified to be responsible for the enhanced pinning in metal organic deposited YBCO films. Rare earth additions result in the formation of nanodots in the YBCO matrix, which form uncorrelated pinning centers, increasing pinning in all magnetic field orientations. 124-type intergrowths, which form as laminar structures parallel to the ab-plane, are responsible for the large current enhancement when the magnetic field is oriented in the ab-plane. TEM studies showed that the intergrowths emanate from cuprous containing secondary phase particles, whose density is partially controlled by the rare earth doping level. Critical process parameters have been identified to control this phase formation, and therefore, control the f 24 intergrowth formation. This work has shown that through process control and proper conductor design, either by adjusting the composition or by multiple coatings of different functional layers, the desired angular dependence can be achieved.

  19. Flux flow and pinning by twin boundaries in single crystal YBa2Cu3O7-δ

    International Nuclear Information System (INIS)

    Kwok, W.K.; Fleshler, S.; Welp, U.; Vinokur, V.M.; Downey, J.; Crabtree, G.W.

    1993-01-01

    We present AC magnetoresistance measurements in fully oxygenated and oxygen deficient single crystals of YBa 2 Cu 3 O 7-δ . From the resistive broadening in magnetic field for H parallel ab parallel I and H parallel ab perpendicular to I, we demonstrate the existence of Lorentz force induced flux flow dissipation near T c . Using a novel crossed magnetic field technique where high angular resolution of Δθ 2 Cu 3 O 7-δ single crystals. The twin boundary pinning onset is characterized by a critical angle model and we extract a phase diagram for the onset of twin boundary pinning. We report on a strong magnetic field dependence of the critical angle for twin boundary pinning for H parallel c which is absent for H parallel ab. In addition, we find the critical angle θ * for H parallel c is greater than that observed for H parallel ab for nearly stoichiometric samples. (orig.)

  20. Flux pinning mechanism and Hc2-anisotropy in melanin doped bulk MgB2

    Science.gov (United States)

    Shahabuddin Shah, M.; Shahabuddin, Mohammed; Alzayed, Nasser S.; Parakkandy, Jafar M.

    2014-06-01

    Flux pinning mechanism in melanin doped MgB2 superconductor has been studied using a scaling law proposed by Dew-Hughes and another method proposed by Eisterer. Our experimental data could be fitted very closely by the aforementioned scaling law. The fitting parameters, the positions of peaks bpeak and k = bpeak/bn confirm a grain-boundary pinning in the 10% melanin doped sample, while the undoped sample consists of mixed pinning. Furthermore, percolation theory was utilized under grain-boundary approximation to investigate the role of Hc2-anisotropy in the critical current density, and its dependence on applied field as well as temperature. The Hc2-anisotropy decreases with melanin doping resulting in the increase of Jc in high field. There is suppression of flux pinning maximum due to melanin doping, which is found to be the main reason for the degradation of low-field Jc.

  1. FFTF [Fast Flux Test Facility]/IEM [Interim Examination and Maintenance] Cell Fuel Pin Weighing System

    International Nuclear Information System (INIS)

    Gibbons, P.W.

    1987-09-01

    A Fuel Pin Weighing Machine has been developed for use in the Fast Flux Test Facility (FFTF) Interim Examination and Maintenance (IEM) Cell to assist in identifying an individual breached fuel pin from its fuel assembly pin bundle. A weighing machine, originally purchased for use in the Fuels and Materials Examination Facility (FMEF) at Hanford, was used as the basis for the IEM Cell system. Design modifications to the original equipment were centered around: 1) adapting the FMEF machine for use in the IEM Cell and 2) correcting operational deficiencies discovered during functional testing in the IEM Cell Mockup

  2. Flux-Vortex Pinning and Neutron Star Evolution

    Indian Academy of Sciences (India)

    M. Ali Alpar

    2017-09-12

    Sep 12, 2017 ... evolution, outward motion of vortex lines will reduce the dipole magnetic moment in proportion to the rotation rate. The presence of a toroidal array of flux lines makes this mechanism inevitable and independent of the angle between the rotation and magnetic axes. The incompressibility of the flux-line array ...

  3. Flux pinning by voids in surface-oxidized superconducting niobium and vanadium

    International Nuclear Information System (INIS)

    Meij, G.P. van der.

    1984-01-01

    This thesis describes a study of flux pinning by small voids (roughly 10 nm) in the type II superconductors niobium and vanadium. These voids were created in rectangular foils (with typical dimensions of 30x3x0.2 mm) during an irradiation with fast neutrons in the High Flux Reactor at Petten at temperatures between 400 and 1000 0 C. The pinning force per unit volume is determined from the magnetic properties of the superconducting samples. The experiments were carried out in a slowly ramped magnetic field, as well as in a combination of a static and a much smaller alternating field. (Auth.)

  4. Weakening of flux-pinning strength for high-Tc superconductors in an alternating magnetic field

    International Nuclear Information System (INIS)

    Chen, Q.Y.

    1992-01-01

    This paper reports on the flux-pinning forces in high temperature superconductors which were found to be weakened in an ac field as the applied field strength or the frequency increases. In the weakly pinned regime, flux dynamics could be described with the concept of magnetic diffusion. Flux-motion-induced finite resistivity could lead to significant skin-effect which was reflected in the ac screening effectiveness. The frequency dependence of the relative local field within a superconducting hollow cylinder were used to deduce the flux-motion resistivity ρ. For superconducting YB 2 Cu 3 O 7 - x compounds at 77K it was found that ρ ∼(mu, Omega)-cm. The corresponding magnetic diffusion coefficient was ∼ 224 cm 2 /s. At 750 Hz the skin depth is around 1.54 mm as compared with the 2-mm sample wall thickness

  5. Pinning of a curved flux line by macroscopic inclusions in a type II superconductor

    International Nuclear Information System (INIS)

    Shehata, L.N.; Saif, A.G.

    1983-08-01

    The pinning force is calculated as a function of the distance between a curved (or straight) flux line and the centre of a macroscopic superconducting (or normal) ellipsoidal inclusion. When the ellipsoidal tends to a spherical inclusion the results agree with those previously obtained. (author)

  6. Group-decoupled multi-group pin power reconstruction utilizing nodal solution 1D flux profiles

    International Nuclear Information System (INIS)

    Yu, Lulin; Lu, Dong; Zhang, Shaohong; Wang, Dezhong

    2014-01-01

    Highlights: • A direct fitting multi-group pin power reconstruction method is developed. • The 1D nodal solution flux profiles are used as the condition. • The least square fit problem is analytically solved. • A slowing down source improvement method is applied. • The method shows good accuracy for even challenging problems. - Abstract: A group-decoupled direct fitting method is developed for multi-group pin power reconstruction, which avoids both the complication of obtaining 2D analytic multi-group flux solution and any group-coupled iteration. A unique feature of the method is that in addition to nodal volume and surface average fluxes and corner fluxes, transversely-integrated 1D nodal solution flux profiles are also used as the condition to determine the 2D intra-nodal flux distribution. For each energy group, a two-dimensional expansion with a nine-term polynomial and eight hyperbolic functions is used to perform a constrained least square fit to the 1D intra-nodal flux solution profiles. The constraints are on the conservation of nodal volume and surface average fluxes and corner fluxes. Instead of solving the constrained least square fit problem numerically, we solve it analytically by fully utilizing the symmetry property of the expansion functions. Each of the 17 unknown expansion coefficients is expressed in terms of nodal volume and surface average fluxes, corner fluxes and transversely-integrated flux values. To determine the unknown corner fluxes, a set of linear algebraic equations involving corner fluxes is established via using the current conservation condition on all corners. Moreover, an optional slowing down source improvement method is also developed to further enhance the accuracy of the reconstructed flux distribution if needed. Two test examples are shown with very good results. One is a four-group BWR mini-core problem with all control blades inserted and the other is the seven-group OECD NEA MOX benchmark, C5G7

  7. Enhanced flux-pinning in fluorine-free MOD YBCO films by chemical doping

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.T.; Pu, M.H.; Yang, Y. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhang, H. [Department of Physics, Peking University, Beijing 100871 (China); Cheng, C.H. [Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia); Zhao, Y., E-mail: yzhao@swjtu.edu.c [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia)

    2010-11-01

    YBCO films without and with dilute cobalt and zinc doping were prepared on (0 0 l) LaAlO{sub 3} substrate by non-fluorine metal organic deposition method. Effects of dilute cobalt and zinc doping on biaxial texture, microstructure and flux-pinning properties of YBCO films were investigated. The surface density and smoothness of the doped YBCO films have been distinctly improved compared with that of the pure film. Dilute cobalt- and zinc-doped YBCO films exhibit significantly enhanced J{sub c} values in the magnetic field. The best result is achieved in the cobalt-doped YBCO film. At 77 K, J{sub c} values of cobalt-doped film are 1.7 and 5.4 times higher than that of pure film in 0.5 T and 1.5 T, respectively. These results strongly suggest that dilute cobalt and zinc doping is a promising way to increase the current carrying capability of YBCO films.

  8. Flux Pinning Enhancement in YBa2Cu3O7-x Films with BaSnO3 Nanoparticles

    Science.gov (United States)

    2008-10-01

    AFRL-RZ-WP-TP-2008-2231 FLUX PINNING ENHANCEMENT IN YBa2Cu3O7-x FILMS WITH BaSnO3 NANOPARTICLES (POSTPRINT) Chakrapani V. Varanasi, P.N...AND SUBTITLE FLUX PINNING ENHANCEMENT IN YBa2Cu3O7-x FILMS WITH BaSnO3 NANOPARTICLES (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER...Nanoparticles of BaSnO3 were incorporated into YBa2Cu3O7-x (YBCO) films on LaAlO3 substrates for magnetic flux pinning enhancements. More than an order of

  9. Strong-pinning regimes by spherical inclusions in anisotropic type-II superconductors

    Science.gov (United States)

    Willa, R.; Koshelev, A. E.; Sadovskyy, I. A.; Glatz, A.

    2018-01-01

    The current-carrying capacity of type-II superconductors is decisively determined by how well material defect structures can immobilize vortex lines. In order to gain deeper insights into the fundamental pinning mechanisms, we have explored the case of vortex trapping by randomly distributed spherical inclusions using large-scale simulations of the time-dependent Ginzburg–Landau equations. We find that for a small density of particles having diameters of two coherence lengths, the vortex lattice preserves its structure and the critical current j c decays with the magnetic field following a power-law {B}-α with α ≈ 0.66, which is consistent with predictions of strong-pinning theory. For a higher density of particles and/or larger inclusions, the lattice becomes progressively more disordered and the exponent smoothly decreases down to α ≈ 0.3. At high magnetic fields, all inclusions capture a vortex and the critical current decays faster than {B}-1 as would be expected by theory. In the case of larger inclusions with a diameter of four coherence lengths, the magnetic-field dependence of the critical current is strongly affected by the ability of inclusions to capture multiple vortex lines. We found that at small densities, the fraction of inclusions trapping two vortex lines rapidly grows within narrow field range leading to a peak in j c(B)-dependence within this range. With increasing inclusion density, this peak transforms into a plateau, which then smooths out. Using the insights gained from simulations, we determine the limits of applicability of strong-pinning theory and provide different routes to describe vortex pinning beyond those bounds.

  10. Strong-pinning regimes by spherical inclusions in anisotropic type-II superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Willa, R.; Koshelev, A. E.; Sadovskyy, I. A.; Glatz, A.

    2017-11-27

    The current-carrying capacity of type-II superconductors is decisively determined by how well material defect structures can immobilize vortex lines. In order to gain deeper insights into intrinsic pinning mechanisms, we have explored the case of vortex trapping by randomly distributed spherical inclusions using large-scale simulations of the time-dependent Ginzburg-Landau equations. We find that for a small density of particles having diameters of two coherence lengths, the vortex lattice preserves its structure and the critical current jc decays with the magnetic field following a power-law B-a with a ~ 0:66, which is consistent with predictions of strong pinning theory. For higher density of particles and/or larger inclusions, the lattice becomes progressively more disordered and the exponent smoothly decreases down to a ~ 0:3. At high magnetic fields, all inclusions capture a vortex and the critical current decays faster than B-1 as would be expected by theory. In the case of larger inclusions with diameter of four coherence length, the magnetic-field dependence of the critical current is strongly affected by the ability of inclusions to capture multiple vortex lines. We found that at small densities, the fraction of inclusions trapping two vortex lines rapidly grows within narrow field range leading to a shallow peak in jc(B)-dependence within this range. With increasing inclusion density, this peak transforms into a plateau, which then smooths out. Using the insights gained from simulations, we determine the limits of applicability of strong pinning theory and provide different routes to describe vortex pinning beyond those bounds.

  11. Modeling of Hts Applications Using Emtp with Flux-Pinning Scaling Models for Practical Hts Superconductors

    Science.gov (United States)

    Cave, J. R.; Sood, V. K.

    2008-03-01

    The EMTP software (Electromagnetic Transient Program) for modeling the behavior of electric power systems is commonly used to obtain the transient response of system disturbances, for example caused by fault currents. We have developed specific modules describing practical HTS materials that can be used to describe new architectures involving superconducting power devices, for example fault current limiters. These modules include flux-pinning scaling models that vary smoothly in their parameterization of the J-T-B-E (current density, temperature, magnetic field and electric field) surfaces. In addition, the non-linear low temperature materials properties, such as specific heat, are included for a more accurate description of device behavior. The advantage of this approach is that the complex and non-linear flux-pinning and thermal characteristics of HTS devices can be integrated into power network models. The modeling is presented, with an emphasis on fault current limiters where three domains of operating characteristics are identified.

  12. Flux pinning properties of rare earth modified (Bi, Pb)-2212 superconductors

    Science.gov (United States)

    Biju, A.; Abhilash Kumar, R. G.; Aloysius, R. P.; Syamaprasad, U.

    2006-08-01

    The flux pinning properties of (Bi, Pb)-2212 superconductors modified by the addition of rare earth (RE) elements La, Gd and Yb with varying concentrations are studied. Samples were prepared by a conventional solid state route with initial stoichiometry of Bi1.7Pb0.4Sr2Ca1.1Cu2.1RExOy (where RE = La, Gd, Yb and x = 0.0 (pure), 0.1, 0.2, 0.3, 0.4). The samples were characterized by powder x-ray diffraction, scanning electron microscopy, R-T measurements and superconductivity measurements at 64 K. It is found that the addition of these elements considerably enhances the flux pinning strength of the system, and there is also an increase of critical temperature (TC) and critical current density (JC). These values become maximum at optimum concentrations (x = 0.2-0.3), and at higher levels of addition, these values decrease. The results are explained based on the replacement of Sr2+ and/or Ca2+ by RE3+ ions and the associated distortion of the lattice and change in carrier concentration of the system. La and Yb are found to be more effective than Gd in obtaining better flux pinning properties.

  13. Intrinsic flux pinning mechanisms in different thickness MgB2 films

    Directory of Open Access Journals (Sweden)

    C. Yang

    2017-03-01

    Full Text Available MgB2 films in four thickness (60 nm, 200nm, 600nm and 1μm have been fabricated by hybrid physical–chemical vapor deposition technique (HPCVD. By measuring the magnetization hysteresis loops and the resistivity, we have obtained the transport and magnetic properties of the four films. After that, the pinning mechanisms in them were discussed. Comparing the pinning behaviors in these ultrathin films, thin films and thick films, it was found that there exist different pinning types in MgB2 films of different thickness. In combination with the study of the surface morphology, cross-section and XRD results, we concluded that MgB2 films had different growth modes in different growth stages. For thin films, films grew along c axis, and grain boundaries acted as surface pinning. While for thick films, films grew along c axis at first, and then changed to a-b axis growth. As a result, the a-b axis grains acted as strong volume pinning.

  14. Thickness Dependence of Magnetic Relaxation and E-J Characteristics in Superconducting (Gd-Y)-Ba-Cu-O Films with Strong Vortex Pinning

    Energy Technology Data Exchange (ETDEWEB)

    Polat, Ozgur [ORNL; Sinclair IV, John W [ORNL; Zuev, Yuri L [ORNL; Thompson, James R [ORNL; Christen, David K [ORNL; Cook, Sylvester W [ORNL; Kumar, Dhananjay [ORNL; Chen, Y [SuperPower Incorporated, Schenectady, New York; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York

    2011-01-01

    The dependence of the critical current density Jc on temperature, magnetic field, and film thickness has been investigated in (Gd-Y)BaCu-oxide materials of 0.7, 1.4, and 2.8 m thickness. Generally, the Jc decreases with film thickness at investigated temperatures and magnetic fields. The nature and strength of the pinning centers for vortices have been identified through angular and temperature measurements, respectively. These films do not exhibit c-axis correlated vortex pinning, but do have correlated defects oriented near the ab-planes. For all film thicknesses studied, strong pinning dominates at most temperatures. The vortex dynamics were investigated through magnetic relaxation studies in the temperature range of 5 77 K in 1 T and 3 T applied magnetic fields, H || surface-normal. The creep rate S is thickness dependent at high temperatures, implying that the pinning energy is also thickness dependent. Maley analyses of the relaxation data show an inverse power law variation for the effective pinning energy Ueff ~ (J0/J) . Finally, the electric field-current density (E-J) characteristics were determined over a wide range of dissipation by combining experimental results from transport, swept field magnetometry (VSM), and Superconducting Quantum Interference Device (SQUID) magnetometry. We develop a self-consistent model of the combined experimental results, leading to an estimation of the critical current density Jc0(T) in the absence of flux creep.

  15. Flux pinning study of RE barium coper oxide coated conductors for high field magnet applications

    Science.gov (United States)

    Xu, Aixia

    REBa2Cu3O7-δ (REBCO, RE = rare earth) coated conductor (CC) holds great promise for high field magnet applications owing to its strong irreversibility field (Hirr), low electromagnetic anisotropy (γ2), and high critical current density (Jc). The work of this thesis is tightly related to the development of the funded 32 T, all-superconducting magnet project at the NHMFL. My concern is thus for understanding the optimizing of the working parameters of REBCO CC at low temperatures T, and very high magnetic fields H, focusing on how to enhance Ic and to reduce its angular dependence. Increasing the active cross-section is a direct and economical strategy to enhance the current-carrying capability for REBCO coated conductors. Unfortunately, the high Jc in thin REBCO layers is seldom sustained in thick layers because of difficulties of thick film growth control. In the presence of strong 3D (pin separation far less than film thickness) pins, a high and thickness-independent (Jc) should result. One of major tasks of this thesis is to explore what are the effective strong 3D pins that develop a high and thickness-independent Jc. High and weak thickness-dependent Jc at 77 K is obtained on most recent coated conductors, and BZO nanorods and RE2O 3 nanoparticles are identified as strong 3D pins contributing to this respectable Jc performance. At 77 K, we found that the strong pinning of BZO nanorods remains at least up to 9 T, whereas the strong pinning of RE2O3 nanoparticles gradually evolves to weak collective pinning as the irreversibility field is approached. The second principal part of this thesis concentrates on understanding and minimizing the angular dependence of Jc. Our study is based on the following procedure. First, we investigated the angular dependence of Jc (Jc(θ)) in the working condition of the future 32 T all-superconducting magnet, i.e. 4.2 K and high magnetic field up to 31 T. Our work shows that the low temperature Jc(θ) is Ginzburg-Landau-like at

  16. Enhanced flux pinning in MOCVD-YBCO films through Zr additions : systematic feasibility studies.

    Energy Technology Data Exchange (ETDEWEB)

    Aytug, T.; Paranthaman, M.; Specht, E. D.; Zhang, Y.; Kim, K.; Zuev, Y. L.; Cantoni, C.; Goyal, A.; Christen, D. K.; Maroni, V. A.; Chen, Y.; Selvamanickam, V.; ORNL; SuperPower, Inc.

    2010-01-01

    Systematic effects of Zr additions on the structural and flux pinning properties of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films deposited by metal-organic chemical vapor deposition (MOCVD) have been investigated. Detailed characterization, conducted by coordinated transport, x-ray diffraction, scanning and transmission electron microscopy analyses, and imaging Raman microscopy have revealed trends in the resulting property/performance correlations of these films with respect to varying mole percentages (mol%) of added Zr. For compositions {le} 7.5 mol%, Zr additions lead to improved in-field critical current density, as well as extra correlated pinning along the c-axis direction of the YBCO films via the formation of columnar, self-assembled stacks of BaZrO{sub 3} nanodots.

  17. Enhanced flux pinning in MOCVD-YBCO films through Zr additions: systematic feasibility studies

    International Nuclear Information System (INIS)

    Aytug, T; Paranthaman, M; Specht, E D; Zhang, Y; Kim, K; Zuev, Y L; Cantoni, C; Goyal, A; Christen, D K; Maroni, V A; Chen, Y; Selvamanickam, V

    2010-01-01

    Systematic effects of Zr additions on the structural and flux pinning properties of YBa 2 Cu 3 O 7-δ (YBCO) films deposited by metal-organic chemical vapor deposition (MOCVD) have been investigated. Detailed characterization, conducted by coordinated transport, x-ray diffraction, scanning and transmission electron microscopy analyses, and imaging Raman microscopy have revealed trends in the resulting property/performance correlations of these films with respect to varying mole percentages (mol%) of added Zr. For compositions ≤7.5 mol%, Zr additions lead to improved in-field critical current density, as well as extra correlated pinning along the c-axis direction of the YBCO films via the formation of columnar, self-assembled stacks of BaZrO 3 nanodots.

  18. Enhanced flux pinning in MOCVD-YBCO films through Zr additions: systematic feasibility studies

    Energy Technology Data Exchange (ETDEWEB)

    Aytug, T; Paranthaman, M; Specht, E D; Zhang, Y; Kim, K; Zuev, Y L; Cantoni, C; Goyal, A; Christen, D K [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Maroni, V A [Argonne National Laboratory, Argonne, IL 60439 (United States); Chen, Y; Selvamanickam, V, E-mail: aytugt@ornl.go [SuperPower, Incorporated, 450 Duane Avenue, Schenectady, NY 12304 (United States)

    2010-01-15

    Systematic effects of Zr additions on the structural and flux pinning properties of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films deposited by metal-organic chemical vapor deposition (MOCVD) have been investigated. Detailed characterization, conducted by coordinated transport, x-ray diffraction, scanning and transmission electron microscopy analyses, and imaging Raman microscopy have revealed trends in the resulting property/performance correlations of these films with respect to varying mole percentages (mol%) of added Zr. For compositions {<=}7.5 mol%, Zr additions lead to improved in-field critical current density, as well as extra correlated pinning along the c-axis direction of the YBCO films via the formation of columnar, self-assembled stacks of BaZrO{sub 3} nanodots.

  19. FFTF [fast flux tests facility] metal fuel pin sodium bond quality verification

    International Nuclear Information System (INIS)

    Pitner, A.L.

    1989-01-01

    The Fast Flux Tests Facility (FFTF) Series III driver fuel design consists of U-10 Zr fuel slugs contained in a ferritic alloy cladding. A liquid-metal, sodium bond between the fuel and cladding is required to prevent unacceptable temperatures during operation. Excessive voiding or porosity in the sodium thermal bond could result in localized fuel melting during irradiation. It is therefore imperative that bond quality be verified during fabrication of these metal fuel pins prior to irradiation. Cladding stripping of two spare metal fuel pins was successfully performed to inspect the quality of the sodium thermal bond and to compare observed defects in the bond with eddy current measurements. Bond quality was found to be generally good, thereby confirming the fabrication process used to bond the fuel and cladding with liquid-metal sodium to be acceptable. Observed porosity distribution in the sodium bond correlated well with eddy current indications

  20. Weak point disorder in strongly fluctuating flux-line liquids

    Indian Academy of Sciences (India)

    We consider the effect of weak uncorrelated quenched disorder (point defects) on a strongly fluctuating flux-line liquid. We use a hydrodynamic model which is based on mapping the flux-line system onto a quantum liquid of relativistic charged bosons in 2 + 1 dimensions [P Benetatos and M C Marchetti, Phys. Rev. B64 ...

  1. Weak point disorder in strongly fluctuating flux-line liquids

    Indian Academy of Sciences (India)

    Abstract. We consider the effect of weak uncorrelated quenched disorder (point defects) on a strongly fluctuating flux-line liquid. We use a hydrodynamic model which is based on mapping the flux-line system onto a quantum liquid of relativistic charged bosons in 2 + 1 dimensions [P Benetatos and M C Marchetti, Phys. Rev.

  2. Flux pinning in hot isostatically pressed Bi2Sr2CaCu2Ox

    International Nuclear Information System (INIS)

    Miller, D.J.; Sengupta, S.; Hettinger, J.D.; Shi, D.; Gray, K.E.; Nash, A.S.; Goretta, K.C.

    1992-01-01

    Magnetic hysteresis data were taken from 4.2 to 35 K on Bi 2 Sr 2 CaCu 2 O x samples that were hot isostatically pressed at 105 MPa in an inert atmosphere at 825 degree C. One set of samples was pressed for only 15 min while the other was pressed for 120 min. The samples pressed for 15 min contained a high density of dislocations and planar faults, while the samples pressed for 120 min contained fewer dislocations and faults, with most dislocations present within subgrain boundaries. The samples with the complex dislocation/planar fault structures exhibited substantially larger hysteresis loops, suggesting enhanced flux pinning

  3. Flux Pinning and AC Loss in Second Generation High Temperature Superconductor Wires

    Energy Technology Data Exchange (ETDEWEB)

    Paranthaman, Mariappan Parans [ORNL; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York

    2007-01-01

    Major advances have been made in the last 18 years in high-temperature superconductor (HTS) reserach and development, resulting in increased use of HTS materials in commerical and pre-commercial electric-power applications. This new and important book addresses the issues related to flux pinning, AC losses and thick YBCO film growth. Written by top most scientists in the world, it presents the current status and issues related to YBCO coated conductors and the need for further fundamental materials science work in YBCO coated conductor. It will be a useful handbook for years to come.

  4. Determination, by neutron diffraction, of basic interaction forces for flux pinning in superconductors

    International Nuclear Information System (INIS)

    Lippmann, G.; Schelten, J.; Schmatz, W.

    1976-01-01

    A new method has been developed for the determination of the basic interaction force exerted on the flux lines in type II superconductors. From neutron diffraction by flux line lattices in the two-phase system Nb with Nb 2 N precipitates of a well defined metallurgical structure, it is observed that the flux lines are bent due to the presence of pinning centres. A measure for the bending is the width of the rocking curve which is rather directly related to the main basic interaction force (f 2 )sup(1/2). For four specimens with different number densities of precipitates from 1.3 x 10 17 to 1.3 x 10 18 m -3 the force (f 2 )sup(1/2) has been evaluated as a function of the flux density B from the angular widths of the measured rocking curves. These widths ranged from 6' to 4 0 . The basic interaction forces were independent of the number density; at B/Bsub(c2) = 0.5 a value (f 2 )sup(1/2) = 2 x 10 -10 N was obtained. The maximum interaction force K 0 obtained from the pinning force densities for one sample agreed well with (f 2 )sup(1/2). Reasonable agreements result from further comparisons of (f 2 )sup(1/2) with K 0 at B = 0 calculated from superconductivity parameters and also with K 0 S measured by Antesberger and Ullmaier (Antesberger, G. and Ullmaier, H.; 1974, Phil. Mag., vol. 29, 1101) on the alloy NbTa which has a precipitate structure similar to that of the Nb samples. (author)

  5. Superconductivity and flux pinning in Dy added (Bi, Pb)-2212 superconductor

    Science.gov (United States)

    Biju, A.; Sarun, P. M.; Aloysius, R. P.; Syamaprasad, U.

    2006-10-01

    The changes in phase evolution, structural, superconducting and flux pinning properties of (Bi, Pb)-2212 superconductor due to the addition of the rare earth Dy have been studied. Bulk polycrystalline samples were used for the study in which Dy content was varied from x = 0.0 to 0.5 on a general stoichiometry of Bi1.7Pb0.4Sr2Ca1.1Cu2.1DyxOy. It was found that the Dy atoms enter into the structure, replacing Sr and Ca with significant changes in the lattice parameters, microstructure, hole concentration, normal state resistivity and flux pinning strength of the system. Consequently, the critical temperature (TC), critical current density (JC) and the field dependence of JC (JC-B characteristics) of the Dy added samples were found to be enhanced considerably for optimum doping levels. A maximum TC-onset of 93.4 K (for x = 0.4) and a maximum JC of 692 A cm-2 at 64 K (for x = 0.2) were observed for doped samples, as against 75.8 K and 107 A cm-2, respectively, for the pure sample. The enhancement in the superconducting properties, particularly in the JC-B characteristics, due to Dy addition seems to have great technological significance.

  6. Flux pinning mechanism and H{sub c2}-anisotropy in melanin doped bulk MgB{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Shahabuddin Shah, M., E-mail: mshahabuddin@ksu.edu.sa; Shahabuddin, Mohammed; Alzayed, Nasser S.; Parakkandy, Jafar M.

    2014-06-15

    Highlights: • Melanin doping enhances superconducting properties of MgB{sub 2}. • Grain boundary pinning is the dominant pinning mechanism in melanin doped MgB{sub 2}. • Experimental J{sub c} data could be very closely fitted using Percolation model. • Anisotropy is reduced due to melanin doping resulting in increase in J{sub c} in high field. • Pinning force maximum is suppressed due to melanin doping. - Abstract: Flux pinning mechanism in melanin doped MgB{sub 2} superconductor has been studied using a scaling law proposed by Dew-Hughes and another method proposed by Eisterer. Our experimental data could be fitted very closely by the aforementioned scaling law. The fitting parameters, the positions of peaks b{sub peak} and k = b{sub peak}/b{sub n} confirm a grain-boundary pinning in the 10% melanin doped sample, while the undoped sample consists of mixed pinning. Furthermore, percolation theory was utilized under grain-boundary approximation to investigate the role of H{sub c2}-anisotropy in the critical current density, and its dependence on applied field as well as temperature. The H{sub c2}-anisotropy decreases with melanin doping resulting in the increase of J{sub c} in high field. There is suppression of flux pinning maximum due to melanin doping, which is found to be the main reason for the degradation of low-field J{sub c}.

  7. Flux pinning and critical current in layered type-II superconductors in parallel magnetic fields

    International Nuclear Information System (INIS)

    Prokic, V.; Davidovic, D.; Dobrosavljevic-Grujic, L.

    1995-01-01

    We have shown, within the Ginzburg-Landau theory, that the interaction between vortices and normal-metal layers in high-T c superconductor--normal-metal superlattices can cause high critical-current densities j c . The interaction is primarily magnetic, except at very low temperatures T, where the core interaction is dominant. For a lattice of vortices commensurate with an array of normal-metal layers in a parallel magnetic field H, strong magnetic pinning is obtained, with a nonmonotonic critical-current dependence on H, and with j c of the order of 10 7 --10 8 A/cm 2

  8. Flux pinning and Critical current density in La2-xSrxCuO4+d

    Science.gov (United States)

    Mohottala, Hashini; Wells, B. O.; Budnick, J. I.; Hines, W. A.; Moodenbaugh, A. R.; Chou, F. C.

    2006-03-01

    We have studied the magnetic characteristics of the critical states in a series of samples of the type La2-xSrxCuO4+d that is doped with both Sr and excess O incorporated using electrochemistry. These samples spontaneously phase separate and show both a superconducting phase with TC near 40 K and a magnetic phase with TM near 40 K. Our previous studies established that the superconducting phase is similar to an optimally doped sample while the magnetic phase is consistent with the static spin density wave reported for x=1/8 Sr or Ba doped samples. Magnetization data at various temperatures showed large reversibility in all the samples. The critical current densities JC(0) values were at least an order of magnitude smaller than that of the reported values for YBa2Cu3O7-d and La2-xSrxCuO4. At higher fields JC(H) was smaller indicating the existence of weak flux pinning in the system. Based on our magnetization data we conclude that the vortex lattice pinning is different from non-phase separated cuprates. This work was partially supported by the US-DOE through contract DE-FG02-00ER45801 and the Cottrell Scholar Program of the Research Corporation.

  9. Flux pinning and phase transitions in model high-temperature superconductors with columnar defects

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K.H.; Stroud, D. (Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States)); Girvin, S.M. (Department of Physics, Indiana University, Bloomington, Indiana 47405 (United States))

    1993-07-01

    We calculate the degree of flux pinning by defects in model high-temperature superconductors (HTSC's). The HTSC is modeled as a three-dimensional network of resistively shunted Josephson junctions in an external magnetic field, corresponding to a HTSC in the extreme type-II limit. Disorder is introduced either by randomizing the coupling between grains (model-[ital A] disorder) or by removing grains (model-[ital B] disorder). Three types of defects are considered: point disorder, random line disorder, and periodic line disorder; but the emphasis is on random line disorder. Static and dynamic properties of the models are determined by Monte Carlo simulations and by solution of the analogous coupled overdamped Josephson equations in the presence of thermal noise. Random line defects considerably raise the superconducting transition temperature [ital T][sub [ital c

  10. Effect of PVA doping on flux pinning in bulk MgB{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Vajpayee, Arpita [National Physical Laboratory, K.S. Krishnan Marg, New Delhi (India); Awana, V.P.S. [National Physical Laboratory, K.S. Krishnan Marg, New Delhi (India); National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)], E-mail: awana@mail.nplindia.ernet.in; Balamurugan, S.; Takayama-Muromachi, E. [National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Kishan, H. [National Physical Laboratory, K.S. Krishnan Marg, New Delhi (India); Bhalla, G.L. [Department of Physics and Astrophysics, University of Delhi, New Delhi (India)

    2007-11-01

    The synthesis and characterization of PVA (Poly Vinyl Acetate) doped bulk MgB{sub 2} superconductor is reported here. PVA is used as a carbon source. PVA doping effects made two distinguishable contributions: first enhancement of J{sub c} field performance and second an increase in H{sub c2} value, both because of carbon incorporation into MgB{sub 2} crystal lattice. The susceptibility measurement reveals that T{sub c} decreased from 37 to 36 K. Lattice parameter 'a' decreased from 3.085 A to 3.081 A due to the partial substitution of carbon at boron site. PVA doped sample exhibited the J{sub c} values greater than 10{sup 5} A/cm{sup 2} at 5 and 10 K at low fields; which is almost 3 times higher than the pure one, while at high fields the J{sub c} is increased by an order of magnitude in comparison to pure MgB{sub 2}. From {rho}(T)H measurements we found higher T{sub c} values under magnetic field for doped sample; indicating an increase in H{sub c2}. Also the magnetization measurements exhibited a significant enhancement in H{sub irr} value. The improved performance of PVA doped MgB{sub 2} can be attributed to the substitution of carbon at boron site in parent MgB{sub 2} and the resulting impact on the carrier density and impurity scattering. The improved flux pinning behavior could easily be seen from reduced flux pinning force plots.

  11. Comparison study of the flux pinning enhancement of YBCO superconductor with BZO and BZO + Y2O3 mixed phase additions

    Science.gov (United States)

    Sebastian, M. A.; Ebbing, C.; Zhang, W.; Huang, J.; Wang, H.; Chen, S.; Gautum, B.; Wu, J.; Haugan, T.

    2017-12-01

    Adding nanophase defects to YBa2Cu3O7-δ (YBCO) superconductor thin films is well-known to enhance flux pinning, resulting in an increase in current density (J ct ). While many previous studies focused on single phase additions, the addition of several phases simultaneously shows promise in improving current density by combining different pinning mechanisms. This paper compares the effect of the addition of two insulating, nonreactive phases of barium zirconium oxide (BZO) and yttrium oxide Y2O3, both as a single addition of BZO and as a double addition in conjunction with Y2O3. Processing parameters vary the target composition volume percent of BZO from 2-6 vol. %, while maintaining 3 vol. % Y2O3, and the remaining vol. % YBCO. Pulsed laser deposition produced thin films on LaAlO3 (LAO) and SrTiO3 (STO) substrates at various deposition temperatures. Comparison of strong and weak flux pinning mechanisms, current densities, critical temperatures, and microstructures of the resulting films will be presented. Films produced from the 2 vol. % BZO + 3 vol. Y2O3 doped YBCO target at a deposition temperature of 825 °C attained the highest current density. The addition of second phase Y2O3 impacted the film microstructure, resulting in more isotropic behavior when compared to the YBCO films doped with only BZO.

  12. Flux pinning properties in YBCO films with growth-controlled nano-dots and heavy-ion irradiation defects

    Science.gov (United States)

    Sueyoshi, T.; Kotaki, T.; Uraguchi, Y.; Suenaga, M.; Makihara, T.; Fujiyoshi, T.; Ishikawa, N.

    2016-11-01

    In order to clarify the influence of size and spatial distribution of three-dimensional pinning centres (3D-PCs) on hybrid flux pinning, columnar defects (CDs) were installed by using 200 MeV Xe ions along the c-axis direction into quasi-multilayered films consisting of YBa2Cu3Oy layers and pseudo layers of BaSnO3. The positive effect of the BaSnO3 doping on the hybrid flux pinning stands out for the critical current density Jc around B || c in high magnetic field and/or inclined magnetic field off the c-axis, which is more remarkable for the multilayered film grown at higher temperature, possibly due to larger BaSnO3 nano-dots. In the case of the in-plane distributed BaSnO3 nano-dots, the Jc around B || ab is remarkably enhanced, whereas there is a detrimental effect on the Jc around B || c. These imply that the tuning of 3D-PCs is one of the keys to improve the Jc at all magnetic field orientations for the hybrid flux pinning.

  13. 'Pinning and flux dynamics I' in the memory of Professor John Clem

    Science.gov (United States)

    Weber, Harald W.

    2014-04-01

    The local Organizing Committee and the International Advisory Committee of EUCAS 2013 decided to dedicate the Session 'Pinning and Flux Dynamics I' to the memory of Professor John Clem, who passed away on 2 August 2013. Let me briefly summarize John's career and try to convey the incredible loss for the whole superconductor community. John was born in 1938 in Waukegan, a small town in Illinois. After school he obtained several scholarships at the University of Illinois. There he received a BSc in Engineering Physics in 1960, followed by an MSc in Physics in 1962, and earned a PhD focusing on the theory of superconductivity under John Bardeen in 1965. After two years of postdoctoral positions at the University of Maryland and the Technical University of Munich, he joined the Physics Department of the Iowa State University and the Ames Laboratory in 1967, where he spent the rest of his scientific career. He became Full Professor at ISU and Senior Physicist at the Ames Lab in 1975 and was Chairman of the Physics Department from 1982 to 1985. He spent several sabbaticals in the US at IBM Yorktown Heights, Stanford and EPRI in Palo Alto, was named 'Distinguished Professor' at ISU, was a Fellow of the American Physical Society and the Institute of Physics in London and, at the ASC 2012 in Portland he received the IEEE Award for 'Continuing and Significant Contributions in the Field of Applied Superconductivity', especially for his theoretical insight into the nature of vortices in 2D superconductors, which he called 'pancake vortices'. John, who married his high school sweetheart Judy right after college graduation, immediately turned Ames into a much-visited center for scientists from all over the world (including myself), who were interested in vortex physics and the properties of the flux line lattice, flux pinning, flux cutting and vortex dynamics. But it was not only the science at ISU that attracted us, it was also the warm atmosphere created by John and Judy at

  14. Flux-pinning-induced stress and magnetostriction in a superconducting strip under combination of transport current and magnetic field

    Science.gov (United States)

    Yang, Yumei; Wang, Xingzhe

    2017-09-01

    The magnetoelastic properties and behaviors arising from the flux-pinning effect are investigated for a long rectangular superconducting strip subject to a combination of applied transport current and magnetic field. Based on the Bean critical state model and linear elastic theory, the flux-pinning-induced stress in the superconducting strip is analytically obtained under the zero-field cooling condition. In particular, the magnetostriction performance for the strip with a one-sided restraint condition is then investigated. The results show that the trapped magnetic flux is distributed asymmetrically along the y-direction. A non-zero resultant force is consequently observed from the magnetization arising from the applied transport current and magnetic field. An obvious tension stress emerges around the constrained side of the strip along which the highest probability for cracking occurs and leads to a structural instability. The analytical results give insight into the flux-pinning-induced stress and magnetostriction response of the superconducting strip under both complex carrying-current and applied magnetic field conditions. These results may also provide helpful guidance in avoiding the breakdown of high-temperature superconductors.

  15. Functionally different PIN proteins control auxin flux during bulbil development in Agave tequilana.

    Science.gov (United States)

    Abraham Juárez, María Jazmín; Hernández Cárdenas, Rocío; Santoyo Villa, José Natzul; O'Connor, Devin; Sluis, Aaron; Hake, Sarah; Ordaz-Ortiz, José; Terry, Leon; Simpson, June

    2015-07-01

    In Agave tequilana, reproductive failure or inadequate flower development stimulates the formation of vegetative bulbils at the bracteoles, ensuring survival in a hostile environment. Little is known about the signals that trigger this probably unique phenomenon in agave species. Here we report that auxin plays a central role in bulbil development and show that the localization of PIN1-related proteins is consistent with altered auxin transport during this process. Analysis of agave transcriptome data led to the identification of the A. tequilana orthologue of PIN1 (denoted AtqPIN1) and a second closely related gene from a distinct clade reported as 'Sister of PIN1' (denoted AtqSoPIN1). Quantitative real-time reverse transcription-PCR (RT-qPCR) analysis showed different patterns of expression for each gene during bulbil formation, and heterologous expression of the A. tequilana PIN1 and SoPIN1 genes in Arabidopsis thaliana confirmed functional differences between these genes. Although no free auxin was detected in induced pedicel samples, changes in the levels of auxin precursors were observed. Taken as a whole, the data support the model that AtqPIN1 and AtqSoPIN1 have co-ordinated but distinct functions in relation to auxin transport during the initial stages of bulbil formation. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  16. Field of first magnetic flux entry and pinning strength of superconductors for rf application measured with muon spin rotation

    Science.gov (United States)

    Junginger, T.; Abidi, S. H.; Maffett, R. D.; Buck, T.; Dehn, M. H.; Gheidi, S.; Kiefl, R.; Kolb, P.; Storey, D.; Thoeng, E.; Wasserman, W.; Laxdal, R. E.

    2018-03-01

    The performance of superconducting radiofrequency (SRF) cavities used for particle accelerators depends on two characteristic material parameters: field of first flux entry Hentry and pinning strength. The former sets the limit for the maximum achievable accelerating gradient, while the latter determines how efficiently flux can be expelled related to the maximum achievable quality factor. In this paper, a method based on muon spin rotation (μ SR ) is developed to probe these parameters on samples. It combines measurements from two different spectrometers, one being specifically built for these studies and samples of different geometries. It is found that annealing at 1400 °C virtually eliminates all pinning. Such an annealed substrate is ideally suited to measure Hentry of layered superconductors, which might enable accelerating gradients beyond bulk niobium technology.

  17. Flux pinning and superconducting properties of melt-textured NEG-123 superconductor with TiO.sub.2./sub. addition

    Czech Academy of Sciences Publication Activity Database

    Muralidhar, M.; Jirsa, Miloš; Tomita, M.

    2010-01-01

    Roč. 470, 13-14 (2010), s. 592-597 ISSN 0921-4534 R&D Projects: GA ČR GA202/08/0722 Institutional research plan: CEZ:AV0Z10100520 Keywords : flux pinning, NEG-123 * high-Tc superconductors * high temperature levitation Subject RIV: BM - Solid Matter Physics ; Magnet ism Impact factor: 1.407, year: 2010

  18. Studies by neutron diffraction and μSR of flux lattice orientation, pinning, melting and decomposition in high-Tc superconductors

    International Nuclear Information System (INIS)

    Forgan, E.M.; Cubitt, R.; Wylie, M.T.

    1994-01-01

    We review the results of recent microscopic measurements of flux line structures and their breakdown in the high-Tc superconductors BSCCO and YBCO. These results show clear effects of flux of lattice melting, dimensional crossover and pinning. The huge differences in behaviour of the flux lattice in these two materials can be understood theoretically

  19. Flux pinning properties in YBCO films with growth-controlled nano-dots and heavy-ion irradiation defects

    Energy Technology Data Exchange (ETDEWEB)

    Sueyoshi, T., E-mail: tetsu@cs.kumamoto-u.ac.jp [Department of Computer Science and Electrical Engineering, Kumamoto University, 2-39-1, Kurokami Chuo-ku, Kumamoto 860-8555 (Japan); Kotaki, T.; Uraguchi, Y.; Suenaga, M.; Makihara, T.; Fujiyoshi, T. [Department of Computer Science and Electrical Engineering, Kumamoto University, 2-39-1, Kurokami Chuo-ku, Kumamoto 860-8555 (Japan); Ishikawa, N. [Japan Atomic Energy Agency (JAEA), Ibaraki 319-1195 (Japan)

    2016-11-15

    Highlights: • BSO/YBCO multilayered films were irradiated using 200 MeV Xe ions along c-axis. • Size and spatial distribution of BSO were tunned by the multilayering process. • Size effect of nano-dots on Jc stands out for high B and B tilted off c-axis. • In-plane distributed nano-dots show a detrimental effect on the Jc around B || c. • In-plane distributed nano-dots significantly enhance Jc around B || ab. - Abstract: In order to clarify the influence of size and spatial distribution of three-dimensional pinning centres (3D-PCs) on hybrid flux pinning, columnar defects (CDs) were installed by using 200 MeV Xe ions along the c-axis direction into quasi-multilayered films consisting of YBa{sub 2}Cu{sub 3}O{sub y} layers and pseudo layers of BaSnO{sub 3}. The positive effect of the BaSnO{sub 3} doping on the hybrid flux pinning stands out for the critical current density J{sub c} around B || c in high magnetic field and/or inclined magnetic field off the c-axis, which is more remarkable for the multilayered film grown at higher temperature, possibly due to larger BaSnO{sub 3} nano-dots. In the case of the in-plane distributed BaSnO{sub 3} nano-dots, the J{sub c} around B || ab is remarkably enhanced, whereas there is a detrimental effect on the J{sub c} around B || c. These imply that the tuning of 3D-PCs is one of the keys to improve the J{sub c} at all magnetic field orientations for the hybrid flux pinning.

  20. Enhancement of flux pinning properties in nanosized MgO added Bi-2212 superconductor through neutron irradiation

    Science.gov (United States)

    Mohiju, Zaahidah'Atiqah; Hamid, Nasri A.; Abdullah, Yusof

    2017-01-01

    For superconducting material to maintain high critical current density, Jc in any applications, effective flux pinning centers are needed. The addition of small size MgO particles in bulk Bi2Sr2CaCu2O8 (Bi-2212) superconductor has been proven to enhance the effective flux pinning centers in the superconducting material by creating a desired microstructure with appropriate defects. To further enhance the pinning properties, radiation is one of the convenient ways to improve the microstructure of the material that has correlation with basic properties of superconductors. Neutron irradiation is one of the niche techniques that can be used to perform the task. Defects with larger radius have dimension comparable to the coherence length of the material and thus improved its superconducting properties. In this paper, a small amount of nanosized MgO particles was used to create defects in the Bi-2212 superconducting material. The Bi-2212/MgO compounds were heat treated, followed by partial melting and slow cooling. Part of the samples was subjected to neutron irradiation using the TRIGA-MARK-II research reactor at the Malaysian Nuclear Agency. Characterization of non-irradiated and irradiated samples was performed via the temperature dependence on electrical resistance measurements, X-ray Diffraction Patterns (XRD), and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX) analysis. From the analysis, there was changed in the critical current density and transition temperature of samples subjected to neutron irradiation due to formation of point defects in the microstructure. Higher critical current density indicates better flux pinning properties in the Bi-2212/MgO compounds.

  1. Using Strong Solar Coronal Emission Lines as Coronal Flux Proxies

    Science.gov (United States)

    Falconer, David A.; Jordan, Studart D.; Davila, Joseph M.; Thomas, Roger J.; Andretta, Vincenzo; Brosius, Jeffrey W.; Hara, Hirosha

    1997-01-01

    A comparison of Skylab results with observations of the strong EUV lines of Fe XVI at 335 A and 361 A from the Goddard Solar EUV Rocket Telescope and Spectrograph (SERTS) flight of 1989 suggests that these lines, and perhaps others observed with SERTS, might offer good proxies for estimating the total coronal flux over important wavelength ranges. In this paper, we compare SERTS observations from a later, 1993 flight with simultaneous cospatial Yohkoh soft X-ray observations to test this suggestion over the energy range of the Soft X-ray Telescope (SXT) on Yohkoh. Both polynomial and power-law fits are obtained, and errors are estimated, for the SERTS lines of Fe XVI 335 A and 361 A, Fe XV 284 A and 417 A, and Mg IX 368 A. It is found that the power-law fits best cover the full range of solar conditions from quiet Sun through active region, though not surprisingly the 'cooler' Mg IX 368 A line proves to be a poor proxy. The quadratic polynomial fits yield fair agreement over a large range for all but the Mg IX line, but the linear fits fail conspicuously when extrapolated into the quiet Sun regime. The implications of this work for the He 11 304 A line formation problem are briefly considered. The paper concludes with a discussion of the value of these iron lines observed with SERTS for estimating stellar coronal fluxes, as observed for example with the EUVE satellite.

  2. Weak point disorder in strongly fluctuating flux-line liquids

    Indian Academy of Sciences (India)

    Potential techno- logical applications of high-temperature superconductors rely on the pinning of the vortices in order to eliminate dissipative losses from their motion. In addition, ..... (11) where i, j = (x, y), PL ij(q⊥) = q⊥iq⊥j/q2. ⊥ and PT ij (q⊥) = δij − PL ij(q⊥) are longitu- dinal and transverse projection operators and.

  3. The flux-based PIN allocation mechanism can generate either canalyzed or diffuse distribution patterns depending on geometry and boundary conditions.

    Directory of Open Access Journals (Sweden)

    Michael Luke Walker

    Full Text Available Growth and morphogenesis in plants require controlled transport of the plant hormone auxin. An important participant is the auxin effluxing protein PIN, whose polarized subcellular localization allows it to effectively transport auxin large distances through tissues. The flux-based model, in which auxin flux through a wall stimulates PIN allocation to that wall, is a dominant contender among models determining where and in what quantity PIN is allocated to cell walls. In this paper we characterise the behaviour of flux-based PIN allocation models in various tissues of the shoot apical meristem. Arguing from both mathematical analysis and computer simulations, we describe the natural behaviours of this class of models under various circumstances. In particular, we demonstrate the important dichotomy between sink- and source- driven systems, and show that both diffuse and canalized PIN distributions can be generated simultaneously in the same tissue, without model hybridization or variation of PIN-related parameters. This work is performed in the context of the shoot apical and floral meristems and is applicable to the construction of a unified PIN allocation model.

  4. Flux pinning by heavy-ion-irradiation induced linear defects in YBa2Cu3O7 epitaxial films

    International Nuclear Information System (INIS)

    Budhani, R.C.; Zhu, Y.; Suenaga, M.

    1992-01-01

    We report some transport measurements carried out to study flux pinning by heavy-ion-irradiation induced linear defects in Y 1 Ba 2 Cu 3 O 7 films. Our results show that in these in situ deposited films containing a large concentration of defects frozen-in at the time of film growth, a marginal enhancement in critical current density occurs when the density of linear defects 10 /cm 2 , and their diameter of the order of coherence length. This criterion is satisfied by Ag +21 ions. The damage due to Au +24 ions is much too severe to improve the J c

  5. Improved interface growth and enhanced flux pinning in YBCO films deposited on an advanced IBAD-MgO based template

    Science.gov (United States)

    Khan, M. Z.; Zhao, Y.; Wu, X.; Malmivirta, M.; Huhtinen, H.; Paturi, P.

    2018-02-01

    The growth mechanism is studied from the flux pinning point of view in small-scale YBa2Cu3O6+x (YBCO) thin films deposited on a polycrystalline hastelloy with advanced IBAD-MgO based buffer layer architecture. When compared the situation with YBCO films grown on single crystal substrates, the most critical issues that affect the suitable defect formation and thus the optimal vortex pinning landscape, have been studied as a function of the growth temperature and the film thickness evolution. We can conclude that the best critical current property in a wide applied magnetic field range is observed in films grown at relatively low temperature and having intermediate thickness. These phenomena are linked to the combination of the improved interface growth, to the film thickness related crystalline relaxation and to the formation of linear array of edge dislocations that forms the low-angle grain boundaries through the entire film thickness and thus improve the vortex pinning properties. Hence, the optimized buffer layer structure proved to be particularly suitable for new coated conductor solutions.

  6. Strong flux of low-energy neutrons produced by thunderstorms.

    Science.gov (United States)

    Gurevich, A V; Antonova, V P; Chubenko, A P; Karashtin, A N; Mitko, G G; Ptitsyn, M O; Ryabov, V A; Shepetov, A L; Shlyugaev, Yu V; Vildanova, L I; Zybin, K P

    2012-03-23

    We report here for the first time about the registration of an extraordinary high flux of low-energy neutrons generated during thunderstorms. The measured neutron count rate enhancements are directly connected with thunderstorm discharges. The low-energy neutron flux value obtained in our work is a challenge for the photonuclear channel of neutron generation in thunderstorm: the estimated value of the needed high-energy γ-ray flux is about 3 orders of magnitude higher than that one observed.

  7. A high critical current density MOCVD coated conductor with strong vortex pinning centers suitable for very high field use

    International Nuclear Information System (INIS)

    Chen, Z; Kametani, F; Larbalestier, D C; Chen, Y; Xie, Y; Selvamanickam, V

    2009-01-01

    We have made extensive low temperature and high field evaluations of a recent 2.1 μm thick coated conductor (CC) grown by metal-organic chemical vapor deposition (MOCVD) with a view to its use for high field magnet applications, for which its very strong Hastelloy substrate makes it very suitable. This conductor contains dense three-dimensional (Y,Sm) 2 O 3 nanoprecipitates, which are self-aligned in planes tilted ∼7 deg. from the tape plane. Very strong vortex pinning is evidenced by high critical current density J c values of ∼3.1 MA cm -2 at 77 K and ∼43 MA cm -2 at 4.2 K, and by a strongly enhanced irreversibility field H irr , which reaches that of Nb 3 Sn (∼28 T at 1.5 K) at 60 K, even in the inferior direction of H parallel c axis. At 4.2 K, J c values are ∼15% of the depairing current density J d , much the highest of any superconductor suitable for magnet construction.

  8. A high critical current density MOCVD coated conductor with strong vortex pinning centers suitable for very high field use

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z; Kametani, F; Larbalestier, D C [National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Chen, Y; Xie, Y; Selvamanickam, V [SuperPower Incorporated, Schenectady, NY 12304 (United States)], E-mail: zhijun@asc.magnet.fsu.edu

    2009-05-15

    We have made extensive low temperature and high field evaluations of a recent 2.1 {mu}m thick coated conductor (CC) grown by metal-organic chemical vapor deposition (MOCVD) with a view to its use for high field magnet applications, for which its very strong Hastelloy substrate makes it very suitable. This conductor contains dense three-dimensional (Y,Sm){sub 2}O{sub 3} nanoprecipitates, which are self-aligned in planes tilted {approx}7 deg. from the tape plane. Very strong vortex pinning is evidenced by high critical current density J{sub c} values of {approx}3.1 MA cm{sup -2} at 77 K and {approx}43 MA cm{sup -2} at 4.2 K, and by a strongly enhanced irreversibility field H{sub irr}, which reaches that of Nb{sub 3}Sn ({approx}28 T at 1.5 K) at 60 K, even in the inferior direction of H parallel c axis. At 4.2 K, J{sub c} values are {approx}15% of the depairing current density J{sub d}, much the highest of any superconductor suitable for magnet construction.

  9. Flux pinning properties of ErBa2Cu3Oy thin films with BaZrO3 nanorods

    International Nuclear Information System (INIS)

    Haruta, M; Fujiyoshi, T; Sueyoshi, T; Dezaki, K; Ichigosaki, D; Miyahara, K; Miyagawa, R; Mukaida, M; Matsumoto, K; Yoshida, Y; Ichinose, A; Horii, S

    2006-01-01

    ErBa 2 Cu 3 O y (ErBCO) thin films with BaZrO 3 (BZO) nanorods were prepared by a PLD method for an enhancement of the critical current density J c . The values of J c for the ErBCO thin film containing 1.5 wt% BZO (Er15) in magnetic fields are higher than those for the ErBCO thin film containing 0.5 wt% BZO (Er05). The peaks of J c have been observed in the angular dependence of J c in both the films when the magnetic field is applied parallel to the c-axis. It has been found that the peak is attributed to the flux pinning by BZO nanorods oriented parallel to the c-axis. The vortex glass-liquid transition temperature T g and the pinning parameter m were derived by fitting observed electric transport properties to the theoretical expression based on the percolation transition model. The value of T g of Er15 is higher than that of Er05. This result indicates that the vortex glass phase extends to a higher temperature region on increasing the fraction of BZO. The peak of m has been found in the magnetic field dependence. This fact is probably due to matching the density of BZO nanorods with that of fluxoids, which was confirmed by TEM observations

  10. Vortex lattice melting, pinning and kinetics

    International Nuclear Information System (INIS)

    Doniach, S.; Ryu, S.; Kapitulnik, A.

    1994-01-01

    The phenomenology of the high T c superconductors is discussed both at the level of the thermodynamics of melting of the Abrikosov flux lattice and in terms of the melting and kinetics of the flux lattice for a pinned system. The authors review results on 3D melting obtained by a Monte Carlo simulation approach in which the 2D open-quotes pancakeclose quotes vortices are treated as statistical variables. The authors discuss pinning in the context of the strong pinning regime in which the vortex density given in terms of the applied field B is small compared to that represented by an effective field B pin measuring the pinning center density. The authors introduce a new criterion for the unfreezing of a vortex glass on increase of magnetic field or temperature, in the strong pinning, small field unit. The authors model this limit in terms of a single flux line interacting with a columnar pin. This model is studied both analytically and by computer simulation. By applying a tilt potential, the authors study the kinetics of the vortex motion in an external current and show that the resulting current-voltage characteristic follows a basic vortex glass-like scaling relation in the vicinity of the depinning transition

  11. Enhanced flux pinning properties in superconducting YBa{sub 2}Cu{sub 3}O{sub 7−z} films by a novel chemical doping approach

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.T., E-mail: wtwang@swjtu.edu.cn [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Pu, M.H.; Lei, M.; Zhang, H.; Wang, Z. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Zhang, H. [Department of Physics, Peking University, Beijing 100871 (China); Cheng, C.H. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia); Zhao, Y., E-mail: yzhao@swjtu.edu.cn [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia)

    2013-10-15

    Highlights: • Pure and Co-doped YBCO films were prepared by newly-developed chemical method. • The doped films have much denser and smoother surface microstructures. • Significantly enhanced fux-pinning properties have been obtained for dilute Co-doped flm. -- Abstract: Pure and cobalt-doped superconducting YBa{sub 2}Cu{sub 3}O{sub 7−z} (YBCO) films were prepared on (0 0 l) LaAlO{sub 3} substrate by a newly developed polymer-assisted metal organic deposition method. The cobalt-doped YBCO films display much denser and smoother surface microstructures and the superconducting transition temperature T{sub c} spans a small range of 1.7 K with the doping levels. Significantly enhanced flux-pinning properties have been obtained for dilute cobalt-doped film. This may be attributed to the good grain connections and the effective flux pinning centers introduced by cobalt doping.

  12. Fast neutron induced flux pinning in Tl-based high-Tc single crystals and thin films, highly textured tapes and melt-textured bulk 123-superconductors

    International Nuclear Information System (INIS)

    Brandstaetter, G.; Samadi Hosseinalli, G.; Kern, C.; Sauerzopf, F.M.; Schulz, G.W.; Straif, W.; Yang, X.; Weber, H.W.; Hu, Q.Y.

    1999-01-01

    Various compounds (TI-2223, TI-1223, TI-2212) as well as material forms (single crystals, thin films, ceramics, tapes) of TI-based high temperature superconductors were investigated by magnetic and transport techniques. TI-2223 has a very 'low lying' irreversibility line (H parallel e) and negligible critical current densities J c at 77 K. However, the irreversibility line shifts to higher fields and temperatures and J c is strongly enhanced, even at 77 K, after fast neutron irradiation. In contrast, the related TI-1223 compound has a much steeper irreversibility line (H parallel c) similar to that of Y-123. J c is significant up to 77 K, even in the unirradiated state, and can be largely improved by neutron irradiation. Transport measurements made on TI-1223 tapes still show much lower critical current densities. TI-2212 and Tl-2223 thin films have J c 's at 77 K, which are comparable to those of TI-1223 single crystals. Transport measurements on highly textured Bi-2223 tapes as well as flux profile measurements on Nd-123 bulk superconductors confirm the beneficial effects of neutron induced defects (collision cascades) for flux pinning. (author)

  13. Sound power flux measurements in strongly exited ducts with flow

    Science.gov (United States)

    Holland, Keith R.; Davies, Peter O. A. L.; van der Walt, Danie C.

    2002-12-01

    This contribution describes new robust procedures for the measurement of sound power flux at appropriate axial positions along a duct with flow, using pairs of flush wall mounted microphones, or pressure transducers. The technology includes the application of selective averaging, order tracking, and optimized sampling rate methods to identify the small fraction of the total fluctuating wave energy that is being propagated along the flow path in a reverberent, or highly reactive duct system. Such measurements can also be used to quantify the local acoustic characteristics that govern the generation, transfer, and propagation of wave energy in the system. Illustrative examples include the determination of the acoustic characteristics of individual silencing elements installed in IC engine intakes and exhausts both on the flow bench and during controlled acceleration or run down on a test bed, where the wave component spectral levels approached 170 dB.

  14. Vortex pinning and creep experiments

    International Nuclear Information System (INIS)

    Kes, P.H.

    1991-01-01

    A brief review of basic flux-pinning and flux-creep ingredients and a selection of experimental results on high-temperature-superconductivity compounds is presented. Emphasis is put on recent results and on those properties which are central to the emerging understanding of the flux-pinning and flux-creep mechanisms of these fascinating materials

  15. Strong Coupling of a Quantum Oscillator to a Flux Qubit at Its Symmetry Point

    NARCIS (Netherlands)

    Fedorov, A.; Feofanov, A.K.; Macha, P.; Forn-Díaz, P.; Harmans, C.J.P.M.; Mooij, J.E.

    2010-01-01

    A flux qubit biased at its symmetry point shows a minimum in the energy splitting (the gap), providing protection against flux noise. We have fabricated a qubit of which the gap can be tuned fast and have coupled this qubit strongly to an LC oscillator. We show full spectroscopy of the

  16. Effect of sorbic acid doping on flux pinning in bulk MgB{sub 2} with the percolation model

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Y. [Key Laboratory of Advanced Technologies of Materials (Ministry of Education of China), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Key Laboratory of Magnetic Levitation and Maglev Train (Ministry of Education of China), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Cheng, C.H. [School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia); Wang, L.; Sun, H.H. [Key Laboratory of Advanced Technologies of Materials (Ministry of Education of China), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Key Laboratory of Magnetic Levitation and Maglev Train (Ministry of Education of China), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhao, Y., E-mail: yzhao@swjtu.edu.c [Key Laboratory of Advanced Technologies of Materials (Ministry of Education of China), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Key Laboratory of Magnetic Levitation and Maglev Train (Ministry of Education of China), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia)

    2010-11-01

    In this paper, we study the doping effect of sorbic acid (C{sub 6}H{sub 8}O{sub 2}), from 0 to 20 wt.% of the total MgB{sub 2}, on critical temperature (T{sub c}), critical current density (J{sub c}), irreversibility field (H{sub irr}) and crystalline structure. The XRD patterns of samples show a slightly decrease in a-axis lattice parameter for doped samples, due to the partial substitution of carbon at boron site. On the other hand, we investigate the influence of doping on the behavior of flux pinning and J{sub c}(B) in the framework of percolation theory and it is found that the J{sub c}(B) behavior could be well fitted in high field region. The two key parameters, anisotropy and percolation threshold, play very important roles. It is believed that the enhancement of J{sub c} is due to the reduction of anisotropy in high field region.

  17. Flux pinning properties of B-rich and SiC-doped MgB{sub 2} tapes prepared by in situ PIT two-stage heat-treatment process

    Energy Technology Data Exchange (ETDEWEB)

    Miura, O. [Department of Electrical Engineering, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397 (Japan)], E-mail: osuke@eei.metro-u.ac.jp; Saeki, A.; Tomioka, H.; Ito, D. [Department of Electrical Engineering, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397 (Japan); Harada, N. [Department of Electrical and Electronics Engineering, Yamaguchi University, Ube, Yamaguchi 755-8611 (Japan)

    2007-10-01

    B-rich and SiC-doped MgB{sub 2} tapes were fabricated by a modified in situ PIT method with two-stage heat-treatment, using Mg flakes with little oxide film. Combination of heat-treatment and rolling process brought about a dense MgB{sub 2} core and a strong inter granular connectivity. For all B-rich MgB{sub 2} tapes T{sub c} remained almost 38 K, while T{sub c} decreased for SiC-doped MgB{sub 2} tapes. J{sub c} for B-rich tapes increased systematically in whole magnetic fields with the increase of B composition ratio. The maximum J{sub c} values of 1.8 x 10{sup 5} at 20 K, 0 T and 0.84 x 10{sup 3} A/cm{sup 2} at 3 T were obtained for a specimen with the ratio of Mg:B of 1:2.8. The grain size of B-rich tapes was smaller than that of the stoichiometric one. SiC-doped tapes also achieved J{sub c} enhancement mainly in high-fields. Irreversibility fields increased for both MgB{sub 2} tapes. Analyses based on the single vortex pinning theory revealed two factors contributing to the improvement of J{sub c} for B-rich tapes. One is an increase of the grain boundary density and the other is an enhancement of the elementary pinning force at grain boundaries. On the other hand, for SiC-doped tapes, such factors slightly increased compared to B-rich tapes. It is believed that this difference of flux pinning behavior originates in the different flux pinning mechanism.

  18. Enhanced flux pinning in pulsed laser deposited Y Ba 2 Cu 3 O 7-δ : BaTiO 3 nanocomposite thin films

    Science.gov (United States)

    Jha, Alok K.; Khare, Neeraj; Pinto, R.

    2011-10-01

    The effect of incorporation of BaTiO 3(BTO) nanoparticles on the flux pinning properties of pulsed laser deposited YBCO:BTO thin films was studied. Substantial increase in the critical current density ( JC) and the pinning force density ( Fp) of the nanocomposite thin films was observed. At 77 K, and zero applied magnetic field, the value of JC for YBCO and YBCO:BTO (2%) thin films were 2.93 MA/cm 2 and 6.43 MA/cm 2, respectively. At the same temperature and an applied magnetic field of 4 T, the value of JC increases from 3.6×10 4 A/cm 2 for YBCO thin film to 2.7×10 5 A/cm 2 for YBCO:BTO (2%) nanocomposite thin film. The study of temperature and field dependence of J of YBCO and YBCO:BTO thin films indicates similar type of pinning. The lattice mismatch between YBCO and BTO seems to introduce more defects resulting in the improvement of flux pinning properties.

  19. Flux pinning enhancements in YBa2Cu3O7-8 superconductors through phase separated, self-assembled LaMnO3-MgO nanocomposite films.

    Energy Technology Data Exchange (ETDEWEB)

    Polat, Ozgur [ORNL; Aytug, Tolga [ORNL; Paranthaman, Mariappan Parans [ORNL; Leonard, Keith J [ORNL; Pennycook, Stephen J [ORNL; Kim, Kyunghoon [ORNL; Cook, Sylvester W [ORNL; Thompson, James R [ORNL; Christen, David K [ORNL; Goyal, Amit [ORNL; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York; Lupini, Andrew R [ORNL; Meyer, Hendrik [ORNL; Qiu, Xiaofeng [ORNL; Xiong, X. [SuperPower Incorporated, Schenectady, New York

    2011-01-01

    Technological applications of high temperature superconductors (HTS) require high critical current density, Jc, under operation at high magnetic field strengths. This requires effective flux pinning by introducing artificial defects through creative processing. In this work, we generated correlated disorder for strong vortex pinning in the YBa2Cu3O7- (YBCO) films by replacing the standard LaMnO3 (LMO) cap buffer layers in ion beam assisted deposited MgO templates with LMO:MgO composite films. Such films revealed formation of two phase-separated, but at the same time vertically aligned, self-assembled composite nanostructures that extend throughout the entire thickness of the film. Measurements of magnetic-field orientation-dependent Jc of YBCO coatings deposited on these nanostructured cap layers showed correlated c-axis pinning and improved in-field Jc performance compared to those of YBCO films deposited on standard LMO buffers. The present results demonstrate feasibility of novel and potentially practical approaches in the pursuit of more efficient, economical, and high performance superconducting devices.

  20. Approaches in controllable generation of artificial pinning center in REBa2Cu3O y -coated conductor for high-flux pinning

    Science.gov (United States)

    Yoshida, Y.; Miura, S.; Tsuchiya, Y.; Ichino, Y.; Awaji, S.; Matsumoto, K.; Ichinose, A.

    2017-10-01

    This paper reviews the progress of studies to determine optimum shapes of the artificial pinning center (APC) of REBa2Cu3O y thin films and coated conductors towards superconducting magnets operating at temperatures of 77 K or less. Superconducting properties vary depending on the kind and quantity of BaMO3 materials. Therefore, we study changes in the shapes of nanorods that are due to the difference in the quality of additives and growth temperature. In addition, we aim to control the APC using an optimum shape that matches the operating temperature. In particular, we describe the shape control of nanorods in SmBCO thin films and coated conductors by employing lower temperature growth (LTG) technology using seed layers. From the cross-sectional transmission electron microscopy observations, we confirmed that using the LTG method, the BaHfO3 (BHO) nanorods, which were comparatively thin and short in length, formed a firework structure in the case of SmBCO films with coated conductors. The superconducting properties in the magnetic field of the SmBCO-coated conductor with the optimum amount of BHO showed that {F}{{p}}\\max = 1.6 TN m‑3 on a single crystalline substrate and 1.5 TN m‑3 on metallic substrate with a biaxially textured MgO layer fabricated by ion-beam assisted deposition method tape 4.2 K.

  1. Determination of the neutron flux in the reactor zones with the strong neutron absorption and leakage

    International Nuclear Information System (INIS)

    Ljubenov, V.; Milosevic, M.

    2004-01-01

    The procedures for the numerical and experimental determination of the neutron flux in the zones with the strong neutron absorption and leakage are described in this paper. Numerical procedure is based on the SCALE-4.4a code system application with the use of Dancoff factor determined by the VEGA2DAN code. Experimental methodology consists of the irradiated foils activity measurement, and foil averaged neutron absorption cross-section determination via mentioned SCALE- 4.4a calculation procedure. The proposed procedures have been applied for the determination of the neutron flux in the internal neutron converter used with the RB reactor core configuration number 114. (author) [sr

  2. Enhanced flux pinning by BaZrO3 and (Gd,y)2O3 nano-structures in metal organic chemical vapor deposited GdYBCO high temperature superconductor tapes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y [SuperPower Incorporated, Schenectady, New York; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York; Paranthaman, Mariappan Parans [ORNL; Cantoni, Claudia [ORNL; Aytug, Tolga [ORNL; Goyal, Amit [ORNL; Lee, Dominic F [ORNL; Specht, Eliot D [ORNL; Zuev, Yuri L [ORNL; Zhang, Yifei [ORNL

    2009-01-01

    We have formed BaZrO3 nano-columns and (Gd,Y)2O3 nano-precipitates in reel-to-reel MOCVD processed (Gd,Y)Ba2Cu3O7-x coated conductors and increased the critical currents (Ic) of the conductors in applied magnetic fields to remarkable levels. A (Gd,Y)Ba2Cu3O7-x tape of 1m length with 6.5% Zr-additions and 30% composition rich in both Gd and Y showed Ic values of 813 A/cm-width at (self-field, 77K) and above 186 A/cm-width at (1T, 77K). The strongly enhanced flux pinning over a wide range of magnetic field orientations can be attributed to the bidirectionally aligned defect structures of BaZrO3 and (Gd,Y)2O3 created by optimized MOCVD conditions.

  3. Observation of record flux pinning in melt-textured NEG-123 superconductor doped by Nb, Mo, and Ti nanopaticles

    Czech Academy of Sciences Publication Activity Database

    Muralidhar, M.; Tomita, M.; Jirsa, Miloš; Sakai, N.; Murakami, M.; Hirabayashi, I.

    2009-01-01

    Roč. 469, 15-20 (2009), s. 1196-1199 ISSN 0921-4534 R&D Projects: GA ČR GA202/08/0722 Institutional research plan: CEZ:AV0Z10100520 Keywords : NEG-123 * critical currents * record vortex pinning * high-Tc superconductor s * levitation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.723, year: 2009

  4. A Model Approach to Flux-Pinning Properties of YBa2Cu 3O7-delta Thin Film Vortex States via Non-Superconducting Impurities

    Science.gov (United States)

    Gamble, Ronald S., Jr.

    Thin film YBa2Cu3O7--delta (YBCO) samples with added non-superconducting nanodot defects of CeO 2 and BaSnO2 are the focus of recent high-temperature superconductor studies. These nanodots allow magnetic flux to penetrate at these sites of the superconducting lattice thus creating a magnetic flux vortex state. Examining the structure shows that these quantized magnetic flux vortices arrange themselves in a self-assembled lattice. The nanodots, with non-superconducting properties, serve to present structural properties to restrict motion of these vorticies under a pinning-force and to enhance the critical current density. A formulation of a new model for the system by a variation in the electron pair velocity via the virtual work from the nanodot defects in accordance to the well-known Superconductivity theories is tested. A solution to the expression for the magnetic flux, zero net force and pair velocity will generate a setting for the optimal deposition parameters of number density, growth geometry and mass density of these nanodot structures. With a calculation of pair velocities from a similar work, a comparison is made between experimental and theoretical velocity calculations using growth geometry and chemical potential. This will yield insight into how the current density for a doped high-temperature superconductor will be modified and tuned based on the dynamics and density of the nanodots themselves.

  5. Concurrent doping effect of Ti and nano-diamond on flux pinning of MgB{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Y., E-mail: yzhao@swjtu.edu.c [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia); Ke, C. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Cheng, C.H. [Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia); Feng, Y. [Northwest Institute for Nonferrous Metal Research, P.O. Box 51, Xian, Shaanxi 710016 (China); Western Superconductivity Technology Company, Xian (China); Yang, Y. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Munroe, P. [Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia)

    2010-11-01

    Nano-diamond and titanium concurrently doped MgB{sub 2} nanocomposites have been prepared by solid state reaction method. The effects of carbon and Ti concurrent doping on J{sub c}-H behavior and pinning force scaling features of MgB{sub 2} have been investigated. Although T{sub c} was slightly depressed, J{sub c} of MgB{sub 2} have been significantly improved by the nano-diamond doping, especially in the high field region. In the mean time, the J{sub c} value in low field region is sustained though concurrent Ti doping. Microstructure analysis reveals that when nano-diamond was concurrently doped with titanium in MgB{sub 2}, a unique nanocomposite in which TiB{sub 2} forms a thin layer surrounding MgB{sub 2} grains whereas nano-diamond particles were wrapped inside the MgB{sub 2} grains. Besides, nano-diamond doping results in a high density stress field in the MgB{sub 2} samples, which may take responsibility for the {Delta}{kappa} pinning behavior in the carbon-doped MgB{sub 2} system.

  6. Improved flux-pinning properties of REBa{sub 2}Cu{sub 3}O{sub 7-z} films by low-level Co doping

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wentao; Pu, Minghua; Wang, Weiwei; Lei, Ming [Key Laboratory of Magnetic Levitation and Maglev Trains, Ministry of Education of China, Superconductivity R and D Centre (SRDC), Southwest Jiaotong University, Erhuanlu Beiyiduan 111, 610031 Chengdu (China); Cheng, Cuihua [Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wales, 2052 NSW, Sydney (Australia); Zhao, Yong [Key Laboratory of Magnetic Levitation and Maglev Trains, Ministry of Education of China, Superconductivity R and D Centre (SRDC), Southwest Jiaotong University, Erhuanlu Beiyiduan 111, 610031 Chengdu (China); Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wales, 2052 NSW, Sydney (Australia)

    2011-09-15

    Biaxially textured REBa{sub 2}Cu{sub 3-x}Co{sub x}O{sub 7-z} (RE = Gd,Y) films were prepared on (00l) LaAlO{sub 3} substrate using self-developed fluorine-free chemical solution deposition (CSD) approach. The in-field J{sub c} values are significantly improved for REBa{sub 2}Cu{sub 3-x}Co{sub x}O{sub 7-z} films through low-level Co doping. Co-doped GdBa{sub 2}Cu{sub 3}O{sub 7-z} film shows the highest J{sub c} values at higher temperatures and fields, whereas the J{sub c} values of Co-doped YBa{sub 2}Cu{sub 3}O{sub 7-z} film surpass that of other films at lower temperatures and fields. In addition, the volume pinning force densities of films with Co doping have been distinctly enhanced in the applied fields, indicating improved flux-pinning properties. The possible reasons are discussed in detail. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Comparison between nano-diamond and carbon nanotube doping effects on critical current density and flux pinning in MgB2

    International Nuclear Information System (INIS)

    Cheng, C H; Yang, Y; Munroe, P; Zhao, Y

    2007-01-01

    Doping effects of nano-diamond and carbon nanotubes (CNTs) on critical current density of bulk MgB 2 have been studied. CNTs are found prone to be doped into the MgB 2 lattice whereas nano-diamond tends to form second-phase inclusions in the MgB 2 matrix, leading to a more significant improvement of J c (H) by doping by nano-diamond than by CNTs in MgB 2 . TEM reveals tightly packed MgB 2 nanograins (50-100 nm) with a dense distribution of diamond nanoparticles (10-20 nm) inside MgB 2 grains in nano-diamond-doped samples. Such a unique microstructure leads to a flux pinning behaviour different from that in CNTs-doped MgB 2

  8. Energy fluxes in a high Arctic tundra heath subjected to strong climate warming

    Science.gov (United States)

    Lund, M.; Hansen, B. U.; Pedersen, S. H.; Stiegler, C.; Tamstorf, M. P.

    2012-12-01

    During recent decades the observed warming in the Arctic has been almost twice as large as the global average. The implications of such strong warming on surface energy balance, regulating permafrost thaw, hydrology, soil stability and carbon mineralization, need to be assessed. In Zackenberg, northeast Greenland, measurements of energy balance components in various environments have been performed since late 90's, coordinated by Zackenberg Ecological Research Operations. During 1996-2009, mean annual temperature in the area has increased by ca. 0.15 °C yr-1; while maximum thaw depth has increased by 1.4-1.8 cm yr-1. Eddy covariance measurements of energy fluxes have been performed in a Cassiope heath plant community, a commonly occurring tundra ecosystem type in circumpolar middle and high Arctic areas, in Zackenberg allowing for detailed investigations of relationships between energy fluxes and meteorological and soil physical characteristics. As the available data set spans more than a decade, possible trends in energy flux components resulting from warming related changes such as earlier snow melt, increased active layer depth and higher temperatures can be investigated. This presentation will focus on the mid-summer period from which eddy covariance measurements are available. The summer-time energy partitioning at the Zackenberg tundra heath site will be characterized using ratios of sensible, latent and ground heat flux to net radiation and Bowen ratio, whereas the surface characteristics will be described using surface resistance, McNaughton and Jarvis Ω value and Priestley-Taylor α coefficient. Furthermore, we aim to estimate the full year, all energy balance components for the tundra heath site using Snow Model (Liston and Elder 2006) for the dark winter period during which no eddy covariance measurements are available. The snow cover duration in the area is a major regulator of the energy partitioning. Early results point towards high summer

  9. Nondestrucive analysis of fuel pins

    Science.gov (United States)

    Stepan, I.E.; Allard, N.P.; Suter, C.R.

    1972-11-03

    Disclosure is made of a method and a correspondingly adapted facility for the nondestructive analysis of the concentation of fuel and poison in a nuclear reactor fuel pin. The concentrations of fuel and poison in successive sections along the entire length of the fuel pin are determined by measuring the reactivity of a thermal reactor as each successive small section of the fuel pin is exposed to the neutron flux of the reactor core and comparing the measured reactivity with the reactivities measured for standard fuel pins having various known concentrations. Only a small section of the length of the fuel pin is exposed to the neutron flux at any one time while the remainder of the fuel pin is shielded from the neutron flux. In order to expose only a small section at any one time, a boron-10-lined dry traverse tube is passed through the test region within the core of a low-power thermal nuclear reactor which has a very high fuel sensitivity. A narrow window in the boron-10 lining is positioned at the core center line. The fuel pins are then systematically traversed through the tube past the narrow window such that successive small sections along the length of the fuel pin are exposed to the neutron flux which passes through the narrow window.

  10. The flux pinning properties of BaSnO{sub 3}-added GdBa{sub 2}Cu3O{sub 7-δ} films with varying growth conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. K.; Oh, J. Y.; Kang, B. [Dept. of Physics, Chungbuk National University, Cheongju (Korea, Republic of); Lee, J. M.; Kang, W. N. [Dept. of Physics, Sungkyunkwan University, Suwon (Korea, Republic of)

    2017-09-15

    Addition of BaSnO{sub 3} (BSO) to GdBa{sub 2}Cu{sub 3}O{sub 7-δ} (GdBCO) is reported to enhance the flux pinning property of GdBCO thick films. To investigate the effect of growth condition on the pinning properties, 700 nm-thick BSO-added GdBCO films deposited with varying temperatures and growth rates were prepared by using a pulsed laser deposition method. As the deposition temperature increases, the critical current density and the pinning force density show an improved field dependence up to 750 ℃ due to the increase in the formation of the a-axis growth and the BSO nanostructures. The films deposited at higher temperatures show degraded surfaces and as a result, degraded pinning behaviors. For the change in growth rate, the critical current density and the pinning force increase as the repetition rate increase at low magnetic fields, but this behavior is reversed in high magnetic fields. These results indicate that the film growth conditions significantly affect the formation of BSO nanostructures and the pinning properties of BSO-added GdBCO films.

  11. Collective Dynamics and Strong Pinning near the Onset of Charge Order in La1.48Nd0.4Sr0.12CuO4

    Science.gov (United States)

    Baity, P. G.; Sasagawa, T.; Popović, Dragana

    2018-04-01

    The dynamics of charge-ordered states is one of the key issues in underdoped cuprate high-temperature superconductors, but static short-range charge-order (CO) domains have been detected in almost all cuprates. We probe the dynamics across the CO (and structural) transition in La1.48Nd0.4Sr0.12CuO4 by measuring nonequilibrium charge transport, or resistance R as the system responds to a change in temperature and to an applied magnetic field. We find evidence for metastable states, collective behavior, and criticality. The collective dynamics in the critical regime indicates strong pinning by disorder. Surprisingly, nonequilibrium effects, such as avalanches in R , are revealed only when the critical region is approached from the charge-ordered phase. Our results on La1.48Nd0.4Sr0.12CuO4 provide the long-sought evidence for the fluctuating order across the CO transition, and also set important constraints on theories of dynamic stripes.

  12. Matrix chemical ratio and its optimization for highest flux pinning in ternary (Nd-Eu-Gd)Ba.sub.2./sub.Cu.sub.3./sub.O.sub.y./sub..

    Czech Academy of Sciences Publication Activity Database

    Muralidhar, M.; Jirsa, Miloš; Sakai, N.; Murakami, M.

    2002-01-01

    Roč. 15, - (2002), s. 688-693 ISSN 0953-2048. [International Workshop on Processing and Application of Superconducting (RE) BCO Large Grain Materials /3./. Seatle, 11.07.2001-13.07.2001] R&D Projects: GA AV ČR IAA1010919 Institutional research plan: CEZ:AV0Z1010914 Keywords : (Nd-Eu-Gd)Ba 2 Cu 3 O y * flux pinning * irreversibility field * pinning defects Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.138, year: 2002

  13. Pin care

    Science.gov (United States)

    ... Drugs & Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Pin care URL of this page: //medlineplus.gov/ency/patientinstructions/000481.htm Pin care To use the sharing features on this page, please enable JavaScript. Broken bones can be fixed in surgery with metal ...

  14. High-latitude electromagnetic and particle energy flux during an event with sustained strongly northward IMF

    Directory of Open Access Journals (Sweden)

    H. Korth

    2005-06-01

    Full Text Available We present a case study of a prolonged interval of strongly northward orientation of the interplanetary magnetic field on 16 July 2000, 16:00-19:00 UT to characterize the energy exchange between the magnetosphere and ionosphere for conditions associated with minimum solar wind-magnetosphere coupling. With reconnection occurring tailward of the cusp under northward IMF conditions, the reconnection dynamo should be separated from the viscous dynamo, presumably driven by the Kelvin-Helmholtz (KH instability. Thus, these conditions are also ideal for evaluating the contribution of a viscous interaction to the coupling process. We derive the two-dimensional distribution of the Poynting vector radial component in the northern sunlit polar ionosphere from magnetic field observations by the constellation of Iridium satellites together with drift meter and magnetometer observations from the Defense Meteorological Satellite Program (DMSP F13 and F15 satellites. The electromagnetic energy flux is then compared with the particle energy flux obtained from auroral images taken by the far-ultraviolet (FUV instrument on the Imager for Magnetopause to Aurora Global Exploration (IMAGE spacecraft. The electromagnetic energy input to the ionosphere of 51 GW calculated from the Iridium/DMSP observations is eight times larger than the 6 GW due to particle precipitation all poleward of 78° MLAT. This result indicates that the energy transport is significant, particularly as it is concentrated in a small region near the magnetic pole, even under conditions traditionally considered to be quiet and is dominated by the electromagnetic flux. We estimate the contributions of the high and mid-latitude dynamos to both the Birkeland currents and electric potentials finding that high-latitude reconnection accounts for 0.8 MA and 45kV while we attribute <0.2MA and ~5kV to an interaction at lower latitudes having the sense of a viscous interaction. Given that these

  15. Magnetic field orientation dependence of flux pinning in (Gd,Y)Ba2Cu3O7-x coated conductor with tilted lattice and nanostructures

    International Nuclear Information System (INIS)

    Zhang, Y.; Specht, E.D.; Cantoni, C.; Christen, D.K.; Thompson, J.R.; Sinclair, J.W.; Goyal, A.; Zuev, Y.L.; Aytug, T.; Paranthaman, M.P.; Chen, Y.; Selvamanickam, V.

    2009-01-01

    The dependence of the critical current density (J c ) on the orientation of an applied magnetic field was studied for a prototype (Gd,Y)Ba 2 Cu 3 O 7-x (GdYBCO) coated conductor fabricated by MOCVD on an IBAD-MgO template. Additional rare-earth cations (Y and Gd) and Zr were incorporated into the superconducting film to form (Y,Gd) 2 O 3 and BaZrO 3 nanoparticles extended nearly parallel to the a-b planes and to the c-axis, respectively, to enhance the flux pinning. In-field measurement of J c was carried out with electrical current flowing either along or perpendicular to the longitudinal axis of the tape, while a maximum Lorentz force configuration was always maintained. Details in the angular dependence of J c were related to the unique structure of the film, specifically the tilt in the GdYBCO lattice and the tilts in the extended (Y,Gd) 2 O 3 and BaZrO3 nanoparticles. XRD and TEM were used to study the structure of the coated conductor. The effect of the misalignment between the external field H and the internal field B on the angular dependence of J c is discussed.

  16. Magnetic field orientation dependence of flux pinning in (Gd,Y)Ba2Cu3O7-x coated conductor with tilted lattice and nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yifei [ORNL; Specht, Eliot D [ORNL; Cantoni, Claudia [ORNL; Christen, David K [ORNL; Zuev, Yuri L [ORNL; Goyal, Amit [ORNL; Sinclair, J. [University of Tennessee, Knoxville (UTK); Thompson, James R [ORNL; Aytug, Tolga [ORNL; Paranthaman, Mariappan Parans [ORNL; Chen, Y [SuperPower Incorporated, Schenectady, New York; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York

    2009-01-01

    The dependence of the critical current density (J{sub c}) on the orientation of an applied magnetic field was studied for a prototype (Gd,Y)Ba{sub 2}Cu{sub 3}O{sub 7?x} (GdYBCO) coated conductor fabricated by MOCVD on an IBAD-MgO template. Additional rare-earth cations (Y and Gd) and Zr were incorporated into the superconducting film to form (Y,Gd){sub 2}O{sub 3} and BaZrO{sub 3} nanoparticles extended nearly parallel to the a-b planes and to the c-axis, respectively, to enhance the flux pinning. In-field measurement of J{sub c} was carried out with electrical current flowing either along or perpendicular to the longitudinal axis of the tape, while a maximum Lorentz force configuration was always maintained. Details in the angular dependence of J{sub c} were related to the unique structure of the film, specifically the tilt in the GdYBCO lattice and the tilts in the extended (Y,Gd){sub 2}O{sub 3} and BaZrO{sub 3} nanoparticles. XRD and TEM were used to study the structure of the coated conductor. The effect of the misalignment between the external field H and the internal field B on the angular dependence of J{sub c} is discussed.

  17. Formation of Self-Assembled Ba2YNbO6 Nanocolumns and their Contribution to Flux-Pinning and Jc in Nb-doped YBa2Cu3O7- Films

    Energy Technology Data Exchange (ETDEWEB)

    Wee, Sung Hun [ORNL; Goyal, Amit [ORNL; Zuev, Yuri L [ORNL; Cantoni, Claudia [ORNL; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York; Specht, Eliot D [ORNL

    2010-01-01

    Ba{sub 2}RENbO{sub 6} (RE = rare earth elements including Y) compounds are considered new additives for superior flux-pinning in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films due to their excellent chemical inertness to and large lattice mismatches with YBCO. Simultaneous laser ablation of a YBCO target and a Nb metal foil attached to the surface of the target resulted in epitaxial growth of YBCO films having columnar defects comprised of self-aligned Ba{sub 2}YNbO{sub 6} (BYNO) nanorods parallel to the c-axis of the film. Compared to pure YBCO, YBCO+BYNO films exhibited no T{sub c} reduction as well as superior J{sub c} performance with higher self- and in-field J{sub c} by a factor of 1.5-7 and also exhibited a strong J{sub c} peak for H {parallel} c indicative of strong c-axis correlated flux-pinning.

  18. AmeriFlux and EuroFlux: History of a Strong Collaboration that Provided Unique Resources to the Scientific Community

    Science.gov (United States)

    Papale, D.; Agarwal, D.; Biraud, S.; Canfora, E.; Pastorello, G.; Torn, M. S.; Trotta, C.

    2017-12-01

    In 1995 scientific communities in Europe and North America using the eddy covariance technique to measure carbon, water, and energy exchanges between the terrestrial biosphere and the atmosphere started to organize their respective regional networks. Although there was a general interest and agreement to collaborate and exchange information and data between the two communities, these mainly occurred at the single site or individual levels through direct communications rather than systematically across networks. Between 2000 and 2008 common strategies to facilitate data sharing, promote data use across the two networks, and outreach to the scientific community, started to be more deeply discussed. Early on, harmonization across networks was deemed necessary to the success of both networks. This actually required major effort including lengthy discussions, compromises, and interactions between the networks for concrete implementation of common platforms and tools. Topics such as measurement units, variable definitions and labeling, data processing methods, data sharing policy, data distribution systems and formats, were key elements that had to be addressed and agreed upon carefully to build integrated and inter-operable research infrastructures (RIs). Today, AmeriFlux and EuroFlux are the basis, not only of the continental research infrastructures (ICOS in Europe), but they are also the driving force behind FLUXNET, where other regional networks are joining this coalition and contributing to the definition of a common system to make complex measurements accessible and comparable across continents. The latest dataset produced from this collaboration includes data contributed by over 200 sites around the world, with records spanning over two decades of data, and has been downloaded by over 900 users in the first 1.5 years of its publication. The core strategy of this collaboration, critical aspects and implemented solutions, as well as the current state of this effort

  19. Pinning in nonmagnetic borocarbides

    International Nuclear Information System (INIS)

    Zholobenko, A.N.; Mikitik, G.P.; Fil, V.D.; Kim, J.D.; Lee, S.I.

    2005-01-01

    The field dependences of the Labush parameter in nonmagnetic borocarbides are measured by the method which does not require the free flux flow regime. The anticipated critical current densities are estimated. These values are by two orders of magnitude higher than those measured 'directly' in transport (magnetic) experiments. The giant peak-effect in the field dependences of the Labush parameter is revealed in the Y-based borocarbides. Its behavior is well approximated by the collective pinning theory

  20. Pinning, de-pinning and re-pinning of a slowly varying rivulet

    KAUST Repository

    Paterson, C.

    2013-09-01

    The solutions for the unidirectional flow of a thin rivulet with prescribed volume flux down an inclined planar substrate are used to describe the locally unidirectional flow of a rivulet with constant width (i.e. pinned contact lines) but slowly varying contact angle as well as the possible pinning and subsequent de-pinning of a rivulet with constant contact angle and the possible de-pinning and subsequent re-pinning of a rivulet with constant width as they flow in the azimuthal direction from the top to the bottom of a large horizontal cylinder. Despite being the same locally, the global behaviour of a rivulet with constant width can be very different from that of a rivulet with constant contact angle. In particular, while a rivulet with constant non-zero contact angle can always run from the top to the bottom of the cylinder, the behaviour of a rivulet with constant width depends on the value of the width. Specifically, while a narrow rivulet can run all the way from the top to the bottom of the cylinder, a wide rivulet can run from the top of the cylinder only to a critical azimuthal angle. The scenario in which the hitherto pinned contact lines of the rivulet de-pin at the critical azimuthal angle and the rivulet runs from the critical azimuthal angle to the bottom of the cylinder with zero contact angle but slowly varying width is discussed. The pinning and de-pinning of a rivulet with constant contact angle, and the corresponding situation involving the de-pinning and re-pinning of a rivulet with constant width at a non-zero contact angle which generalises the de-pinning at zero contact angle discussed earlier, are described. In the latter situation, the mass of fluid on the cylinder is found to be a monotonically increasing function of the constant width. © 2013 Elsevier Masson SAS. All rights reserved.

  1. Growth temperature dependence of flux pinning properties in ErBa2Cu3Oy thin films with nano-rods

    International Nuclear Information System (INIS)

    Haruta, M.; Sueyoshi, T.; Fujiyoshi, T.; Mukaida, M.; Kai, H.; Matsumoto, K.; Mele, P.; Maeda, T.; Horii, S.

    2011-01-01

    Nano-rods were introduced into ErBa 2 Cu 3 O y thin films to improve J c . Pinning properties depended on the growth temperature of the films. Morphology of nano-rods was affected by the growth temperature. The growth temperature is important to achieve high in-field J c 's. Irreversibility lines and distributions of local critical current density (J cl ) based on the percolation transition model were affected by the growth temperature (T s ) in 3.5 wt.%-BaNb 2 O 6 -doped ErBa 2 Cu 3 O y thin films. The vortex-Bose-glass-like state appeared by the introduction of nano-rods, and this vortex state was affected by T s . The shape and width of the J cl distribution strongly depended on T s . These results are probably caused by variations of the density and the growth direction for nano-rods reflecting T s . The growth temperature is an important factor to achieve higher critical current properties under magnetic fields for coated conductors of rare-earth-based cuprates with nano-rods.

  2. Growth temperature dependence of flux pinning properties in ErBa{sub 2}Cu{sub 3}O{sub y} thin films with nano-rods

    Energy Technology Data Exchange (ETDEWEB)

    Haruta, M., E-mail: haruta.masakazu@kochi-tech.ac.jp [Kochi University of Technology, Tosayamada-cho, Kami-shi, Kochi 782-8502 (Japan); Sueyoshi, T.; Fujiyoshi, T. [Kumamoto University, 2-39-1, Kurokami, Kumamoto 860-8555 (Japan); Mukaida, M.; Kai, H. [Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0385 (Japan); Matsumoto, K.; Mele, P. [Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata-ku, Kitakyushu 804-8550 (Japan); Maeda, T.; Horii, S. [Kochi University of Technology, Tosayamada-cho, Kami-shi, Kochi 782-8502 (Japan)

    2011-11-15

    Nano-rods were introduced into ErBa{sub 2}Cu{sub 3}O{sub y} thin films to improve J{sub c}. Pinning properties depended on the growth temperature of the films. Morphology of nano-rods was affected by the growth temperature. The growth temperature is important to achieve high in-field J{sub c}'s. Irreversibility lines and distributions of local critical current density (J{sub cl}) based on the percolation transition model were affected by the growth temperature (T{sub s}) in 3.5 wt.%-BaNb{sub 2}O{sub 6}-doped ErBa{sub 2}Cu{sub 3}O{sub y} thin films. The vortex-Bose-glass-like state appeared by the introduction of nano-rods, and this vortex state was affected by T{sub s}. The shape and width of the J{sub cl} distribution strongly depended on T{sub s}. These results are probably caused by variations of the density and the growth direction for nano-rods reflecting T{sub s}. The growth temperature is an important factor to achieve higher critical current properties under magnetic fields for coated conductors of rare-earth-based cuprates with nano-rods.

  3. Happy Pinning

    DEFF Research Database (Denmark)

    Fausing, Bent

    2012-01-01

    This is about Pinterest, but with a different approach than usual to social networks. Pinterest is an image site par excellence. The images are as Windows that open outwards and also lets us look inwards and displays the soul and heart, the unintentional or pre-conscious desires. Happy Pinning!...

  4. Pinning by oxygen vacancies in high-Tc superconductors

    International Nuclear Information System (INIS)

    Chudnovsky, E.M.

    1990-01-01

    It is shown that recent data of Murray et al. on spatial correlations in flux lattices of Bi-Sr-Ca-Cu-O (BSCCO) may be explained if one assumes that 1% of oxygen atoms in CuO 2 layers are missing. This estimate, being in remarkable agreement with that deduced by Kes and van der Beek from ac-susceptibility measurements, provides strong confidence that oxygen vacancies are the major source of pinning in BSCCO

  5. Strong localized variations of the low-altitude energetic electron fluxes in the evening sector near the plasmapause

    Directory of Open Access Journals (Sweden)

    E. E. Titova

    1998-01-01

    Full Text Available Specific type of energetic electron precipitation accompanied by a sharp increase in trapped energetic electron flux are found in the data obtained from low-altitude NOAA satellites. These strongly localized variations of the trapped and precipitated energetic electron flux have been observed in the evening sector near the plasmapause during recovery phase of magnetic storms. Statistical characteristics of these structures as well as the results of comparison with proton precipitation are described. We demonstrate the spatial coincidence of localized electron precipitation with cold plasma gradient and whistler wave intensification measured on board the DE-1 and Aureol-3 satellites. A simultaneous localized sharp increase in both trapped and precipitating electron flux could be a result of significant pitch-angle isotropization of drifting electrons due to their interaction via cyclotron instability with the region of sharp increase in background plasma density.Key words. Ionosphere (particle precipitation; wave-particle interaction Magnetospheric Physics (plasmasphere

  6. Damage dosimetry in EL.3 reflector in view of irradiating steels under a strong thermal flux

    International Nuclear Information System (INIS)

    Alberman, A.; Morin, C.; Salon, L.; Meftah, A.

    1978-03-01

    Some A 537 steel samples were irradiated in view of obtaining the correlations between mechanical properties and the thermal dose. The locations that were chosen (DS.8 and DS.9 in EL 3 reflector) make it possible to have a ratio: thermal flux/nickel flux approximately equal to 1000) on bare impact-test specimens. The farthest stages were cadmium screened. A damage dosimetry was effected in both cases for usual fast neutron correlations. The graphite/nickel spectral index such obtained was constant at the medium level but was increasing linearly at the farthest levels. Spectrum calculations using a one-dimensional transport code appear unadapted to recover the spectrum index previously measured inside the reflector (-3%) and also to explain the axial spectrum effect that had been obtained [fr

  7. Net Fluorescein Flux Across Corneal Endothelium Strongly Suggests Fluid Transport is due to Electro-osmosis.

    Science.gov (United States)

    Sanchez, J M; Cacace, V; Kusnier, C F; Nelson, R; Rubashkin, A A; Iserovich, P; Fischbarg, J

    2016-08-01

    We have presented prior evidence suggesting that fluid transport results from electro-osmosis at the intercellular junctions of the corneal endothelium. Such phenomenon ought to drag other extracellular solutes. We have investigated this using fluorescein-Na2 as an extracellular marker. We measured unidirectional fluxes across layers of cultured human corneal endothelial (HCE) cells. SV-40-transformed HCE layers were grown to confluence on permeable membrane inserts. The medium was DMEM with high glucose and no phenol red. Fluorescein-labeled medium was placed either on the basolateral or the apical side of the inserts; the other side carried unlabeled medium. The inserts were held in a CO2 incubator for 1 h (at 37 °C), after which the entire volume of the unlabeled side was collected. After that, label was placed on the opposite side, and the corresponding paired sample was collected after another hour. Fluorescein counts were determined with a (Photon Technology) DeltaScan fluorometer (excitation 380 nm; emission 550 nm; 2 nm bwth). Samples were read for 60 s. The cells utilized are known to transport fluid from the basolateral to the apical side, just as they do in vivo in several species. We used 4 inserts for influx and efflux (total: 20 1-h periods). We found a net flux of fluorescein from the basolateral to the apical side. The flux ratio was 1.104 ± 0.056. That difference was statistically significant (p = 0.00006, t test, paired samples). The endothelium has a definite restriction at the junctions. Hence, an asymmetry in unidirectional fluxes cannot arise from osmosis, and can only point instead to paracellular solvent drag. We suggest, once more, that such drag is due to electro-osmotic coupling at the paracellular junctions.

  8. Using sonic anemometer temperature to measure sensible heat flux in strong winds

    Directory of Open Access Journals (Sweden)

    S. P. Burns

    2012-09-01

    Full Text Available Sonic anemometers simultaneously measure the turbulent fluctuations of vertical wind (w' and sonic temperature (Ts', and are commonly used to measure sensible heat flux (H. Our study examines 30-min heat fluxes measured with a Campbell Scientific CSAT3 sonic anemometer above a subalpine forest. We compared H calculated with Ts to H calculated with a co-located thermocouple and found that, for horizontal wind speed (U less than 8 m s−1, the agreement was around ±30 W m−2. However, for U ≈ 8 m s−1, the CSAT H had a generally positive deviation from H calculated with the thermocouple, reaching a maximum difference of ≈250 W m−2 at U ≈ 18 m s−1. With version 4 of the CSAT firmware, we found significant underestimation of the speed of sound and thus Ts in high winds (due to a delayed detection of the sonic pulse, which resulted in the large CSAT heat flux errors. Although this Ts error is qualitatively similar to the well-known fundamental correction for the crosswind component, it is quantitatively different and directly related to the firmware estimation of the pulse arrival time. For a CSAT running version 3 of the firmware, there does not appear to be a significant underestimation of Ts; however, a Ts error similar to that of version 4 may occur if the CSAT is sufficiently out of calibration. An empirical correction to the CSAT heat flux that is consistent with our conceptual understanding of the Ts error is presented. Within a broader context, the surface energy balance is used to evaluate the heat flux measurements, and the usefulness of side-by-side instrument comparisons is discussed.

  9. Pinning Mechanisms in YBCO Tapes

    CERN Document Server

    Spera, Marcello; Ballarino, Amalia

    2015-01-01

    In this thesis work, a study on flux pinning mechanisms of commercial YBCO tapes is presented. This study has been performed via critical current characterization using transport (via direct I-V curves) and magnetization (via a Vibrating Sample Magnetometer) measurements. The latter ones turned out to be better concerning the comprehension of the pinning landscape of the provided samples, as a wider range of magnetic fields and temperatures is available for those measurements in the setup I used. The comparison of the experimental data with existing theoretical models allowed me to draw a picture of the pinning mechanisms underlying in each sample, and they turned out to be quite different one another. Moreover, for high-performance research tapes, another interesting feature has been found: the counterplay between the self-field critical current and the in-field one. Very well engineered artificial pinning structures limit the self-field critical current density due to the hi...

  10. Effect of nanoscopic ZrO.sub.2./sub. particles on flux pinning in (Nd,Eu,Gd)-123/Gd-211 composites

    Czech Academy of Sciences Publication Activity Database

    Muralidhar, M.; Sakai, N.; Jirsa, Miloš; Murakami, M.; Koshizuka, N.

    2004-01-01

    Roč. 17, - (2004), s. 1129-1132 ISSN 0953-2048 Institutional research plan: CEZ:AV0Z1010914 Keywords : ZrO 2 particles pinning by nanoscopic particles * high T c superconductor s * melt-textured compounds Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.556, year: 2004

  11. Copper ion fluxes through the floating water bridge under strong electric potential.

    Science.gov (United States)

    Giuliani, Livio; D'Emilia, Enrico; Lisi, Antonella; Grimaldi, Settimio; Brizhik, Larissa; Del Giudice, Emilio

    2015-01-01

    We have performed a series of experiments applying high voltage between two electrodes, immersed in two beakers containing bidistilled water in a way similar to experiments conducted by Fuchs and collaborators, which showed that a water bridge can be formed between the two containers. We also observed the formation of water bridge. Moreover, choosing different pairs of electrodes depending on the material they are made up of, we observed that copper ions flow can pass along the bridge if the negative electrode is made up of copper. We show that the direction of the flux not only depends on the applied electrostatic field but on the relative electronegativity of the electrodes too. These results open new perspectives in understanding the properties of water. We suggest a possible explanation of the obtained results.

  12. Analytical method for reconstruction pin to pin of the nuclear power density distribution

    International Nuclear Information System (INIS)

    Pessoa, Paulo O.; Silva, Fernando C.; Martinez, Aquilino S.

    2013-01-01

    An accurate and efficient method for reconstructing pin to pin of the nuclear power density distribution, involving the analytical solution of the diffusion equation for two-dimensional neutron energy groups in homogeneous nodes, is presented. The boundary conditions used for analytic as solution are the four currents or fluxes on the surface of the node, which are obtained by Nodal Expansion Method (known as NEM) and four fluxes at the vertices of a node calculated using the finite difference method. The analytical solution found is the homogeneous distribution of neutron flux. Detailed distributions pin to pin inside a fuel assembly are estimated by the product of homogeneous flux distribution by local heterogeneous form function. Furthermore, the form functions of flux and power are used. The results obtained with this method have a good accuracy when compared with reference values. (author)

  13. Analytical method for reconstruction pin to pin of the nuclear power density distribution

    Energy Technology Data Exchange (ETDEWEB)

    Pessoa, Paulo O.; Silva, Fernando C.; Martinez, Aquilino S., E-mail: ppessoa@con.ufrj.br, E-mail: fernando@con.ufrj.br, E-mail: aquilino@imp.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    An accurate and efficient method for reconstructing pin to pin of the nuclear power density distribution, involving the analytical solution of the diffusion equation for two-dimensional neutron energy groups in homogeneous nodes, is presented. The boundary conditions used for analytic as solution are the four currents or fluxes on the surface of the node, which are obtained by Nodal Expansion Method (known as NEM) and four fluxes at the vertices of a node calculated using the finite difference method. The analytical solution found is the homogeneous distribution of neutron flux. Detailed distributions pin to pin inside a fuel assembly are estimated by the product of homogeneous flux distribution by local heterogeneous form function. Furthermore, the form functions of flux and power are used. The results obtained with this method have a good accuracy when compared with reference values. (author)

  14. Magnetic pinning in superconductor-ferromagnet multilayers

    International Nuclear Information System (INIS)

    Bulaevskii, L. N.; Chudnovsky, E. M.; Maley, M. P.

    2000-01-01

    We argue that superconductor/ferromagnet multilayers of nanoscale period should exhibit strong pinning of vortices by the magnetic domain structure in magnetic fields below the coercive field when ferromagnetic layers exhibit strong perpendicular magnetic anisotropy. The estimated maximum magnetic pinning energy for single vortex in such a system is about 100 times larger than the pinning energy by columnar defects. This pinning energy may provide critical currents as high as 10 6 -10 7 A/cm 2 at high temperatures (but not very close to T c ) at least in magnetic fields below 0.1 T. (c) 2000 American Institute of Physics

  15. Magnetic pinning in superconductor-ferromagnet multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Bulaevskii, L. N. [Department of Physics and Astronomy, CUNY Lehman College 250 Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Chudnovsky, E. M. [Department of Physics and Astronomy, CUNY Lehman College, 250 Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States); Maley, M. P. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2000-05-01

    We argue that superconductor/ferromagnet multilayers of nanoscale period should exhibit strong pinning of vortices by the magnetic domain structure in magnetic fields below the coercive field when ferromagnetic layers exhibit strong perpendicular magnetic anisotropy. The estimated maximum magnetic pinning energy for single vortex in such a system is about 100 times larger than the pinning energy by columnar defects. This pinning energy may provide critical currents as high as 10{sup 6}-10{sup 7} A/cm{sup 2} at high temperatures (but not very close to T{sub c}) at least in magnetic fields below 0.1 T. (c) 2000 American Institute of Physics.

  16. Co-current Doping Effect of Nanoscale Carbon and Aluminum Nitride on Critical Current Density and Flux Pinning Properties of Bulk MgB2 Superconductors

    Science.gov (United States)

    Tripathi, D.; Dey, T. K.

    2018-01-01

    The effect of nanoscale aluminum nitride (n-AlN) and carbon (n-C) co-doping on superconducting properties of polycrystalline bulk MgB2 superconductor has been investigated. Polycrystalline pellets of MgB2 , MgB2 + 0.5 wt% AlN (nano), MgB_{1.99}C_{0.01} and MgB_{1.99}C_{0.01} + 0.5 wt% AlN (nano) have been synthesized by a solid reaction process under inert atmosphere. The transition temperature (TC) estimated from resistivity measurement indicates only a small decrease for C (nano) and co-doped MgB2 samples. The magnetic field response of investigated samples has been measured at 4, 10, and 20 K in the field range ± 6 T. MgB2 pellets co-doped with 0.5 wt% n-AlN and 1 wt% n-C display appreciable enhancement in critical current density (J_C ) of MgB2 in both low (≥ 3 times), as well as, high-field region (≥ 15 times). J_C versus H behavior of both pristine and doped MgB2 pellets is well explained in the light of the collective pinning model. Further, the normalized pinning force density f_p(= F_p/F_{pmax}) displays a fair correspondence with the scaling procedure proposed by Eisterer et al. Moreover, the scaled data of the pinning force density (i.e., f_p{-}h data) of the investigated pellets at different temperature are well interpreted by a modified Dew-Hughes expression reported by Sandu and Chee.

  17. An evaluation of phase separated, self-assembled LaMnO3-MgO nanocomposite films directly on IBAD-MgO as buffer layers for flux pinning enhancements in YBa2YCu3O7-& coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Polat, Ozgur [ORNL; Aytug, Tolga [ORNL; Paranthaman, Mariappan Parans [ORNL; Leonard, Keith J [ORNL; Lupini, Andrew R [ORNL; Pennycook, Stephen J [ORNL; Meyer III, Harry M [ORNL; Kim, Kyunghoon [ORNL; Qiu, Xiaofeng [ORNL; Cook, Sylvester W [ORNL; Thompson, James R [ORNL; Christen, David K [ORNL; Goyal, Amit [ORNL; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York; Xiong, X. [SuperPower Incorporated, Schenectady, New York

    2010-01-01

    Technological applications of high temperature superconductors (HTS) require high critical current density, Jc, under operation at high magnetic field strengths. This requires effective flux pinning by introducing artificial defects through creative processing. In this work, we evaluated the feasibility of mixed-phase LaMnO3:MgO (LMO:MgO) films as a potential cap buffer layer for the epitaxial growth and enhanced performance of YBa2Cu3O7-d (YBCO) films. Such composite films were sputter deposited directly on IBAD-MgO templates (with no additional homo-epitaxial MgO layer) and revealed the formation of two phase-separated, but at the same time vertically aligned, self-assembled composite nanostructures that extend throughout the entire thickness of the film. The YBCO coatings deposited on these nanostructured cap layers showed correlated c-axis pinning and improved in-field Jc performance compared to those of YBCO films fabricated on standard LMO buffers. Microstructural characterization revealed additional extended disorder in the YBCO matrix. The present results demonstrate the feasibility of novel and potentially practical approaches in the pursuit of more efficient, economical, and high performance superconducting devices.

  18. Enhanced Flux Pinning and Critical Current Density via Incorporation of Self-Assembled Rare-Earth Barium Tantalate Nanocolumns within YBa2Cu3O7-δ Films

    Energy Technology Data Exchange (ETDEWEB)

    Wee, Sung Hun [ORNL; Goyal, Amit [ORNL; Specht, Eliot D [ORNL; Cantoni, Claudia [ORNL; Zuev, Yuri L [ORNL; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York; Cook, Sylvester W [ORNL

    2010-01-01

    We report rare earth barium tantalates, Ba2RETaO6 (BRETO, RE = rare earth elements) as a new class of additives for superior flux-pinning in YBa2Cu3O7- (YBCO) films. BRETO compounds have excellent chemical inertness to and large lattice mismatch with YBCO. This results in phase separation and strain minimization driven self-assembly of BRETO nanocolumns within YBCO films. YBCO+4 vol% Ba2GdTaO6 films show similar Tc to that of an un-doped film of ~ 88.3 K, a higher self-field Jc of 3.8 MA/cm2 at 77 K, and significantly improved in-field Jc higher by a factor of 1.5-6 over entire magnetic field and angular ranges.

  19. Flux

    DEFF Research Database (Denmark)

    Ravn, Ib

    . FLUX betegner en flyden eller strømmen, dvs. dynamik. Forstår man livet som proces og udvikling i stedet for som ting og mekanik, får man et andet billede af det gode liv end det, som den velkendte vestlige mekanicisme lægger op til. Dynamisk forstået indebærer det gode liv den bedst mulige...... kanalisering af den flux eller energi, der strømmer igennem os og giver sig til kende i vore daglige aktiviteter. Skal vores tanker, handlinger, arbejde, samvær og politiske liv organiseres efter stramme og faste regelsæt, uden slinger i valsen? Eller skal de tværtimod forløbe ganske uhindret af regler og bånd...

  20. The extent to which ATP demand controls the glycolytic flux depends strongly on the organism and conditions for growth

    DEFF Research Database (Denmark)

    Købmann, Brian Jensen; Westerhoff, H.V.; Snoep, J.L.

    2002-01-01

    Using molecular genetics we have introduced uncoupled ATPase activity in two different bacterial species, Escherichia coli and Lactococcus lactis, and determined the elasticities of the growth rate and glycolytic flux towards the intracellular [ATP]/[ADP] ratio. During balanced growth in batch...... cultures of E. coli the ATP demand was found to have almost full control on the glycolytic flux (FCC=0.96) and the flux could be stimulated by 70%. In contrast to this, in L. lactis the control by ATP demand on the glycolytic flux was close to zero. However, when we used non-growing cells of L. lactis...... (which have a low glycolytic flux) the ATP demand had a high flux control and the flux could be stimulated more than two fold. We suggest that the extent to which ATP demand controls the glycolytic flux depends on how much excess capacity of glycolysis is present in the cells....

  1. Electro-optical fuel pin identification system

    International Nuclear Information System (INIS)

    Kirchner, T.L.

    1978-09-01

    A prototype Electro-Optical Fuel Pin Identification System referred to as the Fuel Pin Identification System (FPIS) has been developed by the Hanford Engineering Development Laboratory (HEDL) in support of the Fast Flux Test Facility (FFTF) presently under construction at HEDL. The system is designed to remotely read an alpha-numeric identification number that is roll stamped on the top of the fuel pin end cap. The prototype FPIS consists of four major subassemblies: optical read head, digital compression electronics, video display, and line printer

  2. Greatly enhanced flux pinning properties of fluorine-free metal–organic decomposition YBCO films by co-addition of halogens (Cl, Br) and metals (Zr, Sn, Hf)

    Science.gov (United States)

    Motoki, Takanori; Ikeda, Shuhei; Nakamura, Shin-ichi; Honda, Genki; Nagaishi, Tatsuoki; Doi, Toshiya; Shimoyama, Jun-ichi

    2018-04-01

    Additive-free YBCO films, as well as those with halogen (X) added, metal (M) added and (X, M) co-added, have been prepared by the fluorine-free metal–organic decomposition method on SrTiO3(100) single crystalline substrates, where X = Cl, Br and M = Zr, Sn, Hf. It was revealed that the addition of both Cl and Br to the starting solution resulted in the generation of oxyhalide, Ba2Cu3O4 X 2, in the YBCO films, and that the oxyhalide was found to promote the bi-axial orientation of the YBCO crystals. By adding a decent amount of Cl or Br, highly textured YBCO films with high J c were reproducibly obtained, even when an impurity metal, M, was co-added, while the addition of M without X did not greatly improve J c owing to the poor bi-axial orientation of the YBCO crystals. Our results suggest that the addition of Br more effectively enhances J c than the addition of Cl. The pinning force density at 40 K in 4.8 T reached ∼55 GN m‑3 with the co-addition of (Br, M). This value is much larger than that of the pure YBCO film, reaching ∼17 GN m‑3.

  3. Thermodynamics of Meissner effect and flux pinning behavior in the bulk of single-crystal La2-xSrxCuO4 ( x=0.09 )

    Energy Technology Data Exchange (ETDEWEB)

    Dhiman, I.; Ziesche, R.; Anand, V. K.; Riik, L.; Song, Gian; Islam, A. T. M. N.; Tanaka, Isao; Treimer, W.

    2017-09-01

    We have studied the magnetic flux pinning behavior and Meissner effect for the high-$T_{\\rm c}$ single crystal La$_{2-x}$Sr$_{x}$CuO$_{4}$ ($x$ = 0.09) superconductor using the polarized neutron imaging method with varying magnetic field and temperature. In the Meissner state expulsion of magnetic field (switched on during the measurements) is visualized, and the signatures of mixed state with increasing temperature are observed. While, for flux pinning behavior between 5 K $\\leq$ $T$ $\\leq$ 15 K and $H_{\\rm ext}$ = 63.5 mT (switched off during the measurements), the evolution of fringe pattern for both 0$^{o}$ and 90$^{o}$ sample orientation indicates magnetic flux pinning inside the bulk of the sample. At 25 K $\\leq$ $T$ $\\leq$ 32 K, a continuous decrease of inhomogeneously distribution pinned magnetic flux is observed, with the sample reaching a normal conducting state at $T_{\\rm c}$ ($\\approx$ 32 K). The flux pinning behavior is also explored as a function of $H_{\\rm ext}$, at $T$ = 5 K. As expected, with increasing $H_{\\rm ext}$ an increase in fringe density is observed, indicating an increase in magnetic flux pinning in the bulk of the sample. Therefore, in the present work for the first time we report bulk visualization of Meissner effect and flux pinning behavior in high-$T_{\\rm c}$ La$_{2-x}$Sr$_{x}$CuO$_{4}$ ($x$ = 0.09) superconductor. This study clearly demonstrates the potential of real space polarized neutron imaging technique for the visualization of the superconducting mixed state, particularly in the field of high-$T_{\\rm c}$ superconductors.

  4. Strong low-pass filtering effects on water vapour flux measurements with closed-path eddy correlation systems

    DEFF Research Database (Denmark)

    Ibrom, Andreas; Dellwik, Ebba; Flyvbjerg, Henrik K.

    2007-01-01

    forest in Soro, Zealand, Denmark, amounted on average to 42% of the measured flux, while it was only 4% for the CO2 flux, which was measured with the same EC system. We recommend using the described method to correct water vapour fluxes measured in any closed-path EC system for unintended low......Turbulent water vapour fluxes measured with closed-path eddy correlation (EC) systems are unintentionally low-pass filtered by the system in a manner that varies with environmental conditions. Why and how is described here. So is the practical method that systematically corrects long-term flux...... datasets for this substantial measurement error. In contrast to earlier studies, a large number of spectra and raw data have been used in the analysis to define the low-pass filtering characteristic of the EC system. This revealed that the cut-off frequency of the closed-path EC system for water vapour...

  5. Accretion disc dynamo activity in local simulations spanning weak-to-strong net vertical magnetic flux regimes

    Science.gov (United States)

    Salvesen, Greg; Simon, Jacob B.; Armitage, Philip J.; Begelman, Mitchell C.

    2016-03-01

    Strongly magnetized accretion discs around black holes have attractive features that may explain enigmatic aspects of X-ray binary behaviour. The structure and evolution of these discs are governed by a dynamo-like mechanism, which channels part of the accretion power liberated by the magnetorotational instability (MRI) into an ordered toroidal magnetic field. To study dynamo activity, we performed three-dimensional, stratified, isothermal, ideal magnetohydrodynamic shearing box simulations. The strength of the self-sustained toroidal magnetic field depends on the net vertical magnetic flux, which we vary across almost the entire range over which the MRI is linearly unstable. We quantify disc structure and dynamo properties as a function of the initial ratio of mid-plane gas pressure to vertical magnetic field pressure, β _0^mid = p_gas / p_B. For 10^5 ≥ β _0^mid ≥ 10 the effective α-viscosity parameter scales as a power law. Dynamo activity persists up to and including β _0^mid = 10^2, at which point the entire vertical column of the disc is magnetic pressure dominated. Still stronger fields result in a highly inhomogeneous disc structure, with large density fluctuations. We show that the turbulent steady state βmid in our simulations is well matched by the analytic model of Begelman et al. describing the creation and buoyant escape of toroidal field, while the vertical structure of the disc can be broadly reproduced using this model. Finally, we discuss the implications of our results for observed properties of X-ray binaries.

  6. Evidence for carbon flux shortage and strong carbon/nitrogen interactions in pea nodules at early stages of water stress.

    Science.gov (United States)

    Gálvez, Loli; González, Esther M; Arrese-Igor, Cesar

    2005-09-01

    Symbiotic N2 fixation in legume nodules declines under a wide range of environmental stresses. A high correlation between N2 fixation decline and sucrose synthase (SS; EC 2.4.1.13) activity down-regulation has been reported, although it has still to be elucidated whether a causal relationship between SS activity down-regulation and N2 fixation decline can be established. In order to study the likely C/N interactions within nodules and the effects on N2 fixation, pea plants (Pisum sativum L. cv. Sugar snap) were subjected to progressive water stress by withholding irrigation. Under these conditions, nodule SS activity declined concomitantly with apparent nitrogenase activity. The levels of UDP-glucose, glucose-1-phosphate, glucose-6-phosphate, and fructose-6-phosphate decreased in water-stressed nodules compared with unstressed nodules. Drought also had a marked effect on nodule concentrations of malate, succinate, and alpha-ketoglutarate. Moreover, a general decline in nodule adenylate content was detected. NADP+-dependent isocitrate dehydrogenase (ICDH; EC 1.1.1.42) was the only enzyme whose activity increased as a result of water deficit, compensating for a possible C/N imbalance and/or supplying NADPH in circumstances that the pentose phosphate pathway was impaired, as suggested by the decline in glucose-6-phosphate dehydrogenase (G6PDH; EC 1.1.1.49) activity. The overall results show the occurrence of strong C/N interactions in nodules subjected to water stress and support a likely limitation of carbon flux that might be involved in the decline of N2 fixation under drought.

  7. Unified Scaling Law for flux pinning in practical superconductors: III. Minimum datasets, core parameters, and application of the Extrapolative Scaling Expression

    Science.gov (United States)

    Ekin, Jack W.; Cheggour, Najib; Goodrich, Loren; Splett, Jolene

    2017-03-01

    In Part 2 of these articles, an extensive analysis of pinning-force curves and raw scaling data was used to derive the Extrapolative Scaling Expression (ESE). This is a parameterization of the Unified Scaling Law (USL) that has the extrapolation capability of fundamental unified scaling, coupled with the application ease of a simple fitting equation. Here in Part 3, the accuracy of the ESE relation to interpolate and extrapolate limited critical-current data to obtain complete I c(B,T,ɛ) datasets is evaluated and compared with present fitting equations. Accuracy is analyzed in terms of root mean square (RMS) error and fractional deviation statistics. Highlights from 92 test cases are condensed and summarized, covering most fitting protocols and proposed parameterizations of the USL. The results show that ESE reliably extrapolates critical currents at fields B, temperatures T, and strains ɛ that are remarkably different from the fitted minimum dataset. Depending on whether the conductor is moderate-J c or high-J c, effective RMS extrapolation errors for ESE are in the range 2-5 A at 12 T, which approaches the I c measurement error (1-2%). The minimum dataset for extrapolating full I c(B,T,ɛ) characteristics is also determined from raw scaling data. It consists of one set of I c(B,ɛ) data at a fixed temperature (e.g., liquid helium temperature), and one set of I c(B,T) data at a fixed strain (e.g., zero applied strain). Error analysis of extrapolations from the minimum dataset with different fitting equations shows that ESE reduces the percentage extrapolation errors at individual data points at high fields, temperatures, and compressive strains down to 1/10th to 1/40th the size of those for extrapolations with present fitting equations. Depending on the conductor, percentage fitting errors for interpolations are also reduced to as little as 1/15th the size. The extrapolation accuracy of the ESE relation offers the prospect of straightforward implementation of

  8. Development of instrumentation for fuel pin scanner

    International Nuclear Information System (INIS)

    Saisubalakshmi, D.; Parthasarathy, R.; Brahmaji Rao, J.S.; Senthilvadivu, E.; Seshadreesan, N.P.

    2011-01-01

    A study is being carried out using a surrogate vibro-packed fuel pin with micro-spheres of two different sizes to get the density distribution by gamma transmission technique. A shielded (with 2 mm slit of ∼ 2''SS collimator) LaBr scintillation detector is used as the detector system. A strong 137 Cs source is used as the source. The source strength as it is transmitted through the fuel pin is measured by the scintillation detector. The entire length of the fuel pin is gradually moved up from one end to other end and the detector is allowed to continuously examine the transmission profile of the fuel pin. The instrumentation for the fuel pin scanner has been developed and is integrated with the system. The instrumentation includes microcontroller based motor control system and customized detector pulse counting systems. The systems are interfaced to a computer through serial communication. (author)

  9. Experimental investigation of effect of surface gravity waves and spray on heat and momentum flux at strong wind conditions

    Science.gov (United States)

    Troitskaya, Yuliya; Sergeev, Daniil; Vdovin, Maxim; Kandaurov, Alexander; Ermakova, Olga; Kazakov, Vassily

    2015-04-01

    The most important characteristics that determine the interaction between atmosphere and ocean are fluxes of momentum, heat and moisture. For their parameterization the dimensionless exchange coefficients (the surface drag coefficient CD and the heat transfer coefficient or the Stanton number CT) are used. Numerous field and laboratory experiments show that CD increases with increasing wind speed at moderate and strong wind, and as it was shows recently CD decreases at hurricane wind speed. Waves are known to increase the sea surface resistance due to enhanced form drag, the sea spray is considered as a possible mechanism of the 'drag reduction' at hurricane conditions. The dependence of heat transfer coefficient CD on the wind speed is not so certain and the role of the mechanism associated with the wave disturbances in the mass transfer is not completely understood. Observations and laboratory data show that this dependence is weaker than for the CD, and there are differences in the character of the dependence in different data sets. The purpose of this paper is investigation of the effect of surface waves on the turbulent exchange of momentum and heat within the laboratory experiment, when wind and wave parameters are maintained and controlled. The effect of spray on turbulent exchange at strong winds is also estimated. A series of experiments to study the processes of turbulent exchange of momentum and heat in a stably stratified temperature turbulent boundary layer air flow over waved water surface were carried out at the Wind - wave stratified flume of IAP RAS, the peculiarity of this experiment was the option to change the surface wave parameters regardless of the speed of the wind flow in the channel. For this purpose a polyethylene net with the variable depth (0.25 mm thick and a cell of 1.6 mm × 1.6mm) has been stretched along the channel. The waves were absent when the net was located at the level of the undisturbed water surface, and had maximum

  10. Pin potential effect on vortex pinning in YBa2Cu3O7-δ films containing nanorods: Pin size effect and mixed pinning

    Science.gov (United States)

    Horide, Tomoya; Matsukida, Naoki; Ishimaru, Manabu; Kita, Ryusuke; Awaji, Satoshi; Matsumoto, Kaname

    2017-01-01

    The pin size effect and mixed pinning of nanorods and matrix defects are discussed for YBa2Cu3O7-δ films containing nanorods. BaSnO3 nanorods with a diameter of 11 nm and BaHfO3 nanorods with a diameter of 7 nm were prepared, and critical current density (Jc) and resistivity were measured in the films. When the coherence length was larger than the nanorod size at high temperatures near the critical temperature, the trapping angle and activation energy of the vortex flow depended on the nanorod diameter. At a moderate temperature of 65-77 K, the pin size effect on Jc disappeared since the coherence length became smaller than the nanorod size. At a low temperature of 20 K, the contribution from matrix pinning became comparable to that of nanorods in a high magnetic field due to the small coherence length. Thus, the temperature-dependent coherence length caused the pin potential situation to vary significantly, namely, the pin size effect and mixed pinning, which strongly affected vortex pinning in YBa2Cu3O7-δ containing nanorods.

  11. Nuclear fuel pin scanner

    Science.gov (United States)

    Bramblett, Richard L.; Preskitt, Charles A.

    1987-03-03

    Systems and methods for inspection of nuclear fuel pins to determine fiss loading and uniformity. The system includes infeed mechanisms which stockpile, identify and install nuclear fuel pins into an irradiator. The irradiator provides extended activation times using an approximately cylindrical arrangement of numerous fuel pins. The fuel pins can be arranged in a magazine which is rotated about a longitudinal axis of rotation. A source of activating radiation is positioned equidistant from the fuel pins along the longitudinal axis of rotation. The source of activating radiation is preferably oscillated along the axis to uniformly activate the fuel pins. A detector is provided downstream of the irradiator. The detector uses a plurality of detector elements arranged in an axial array. Each detector element inspects a segment of the fuel pin. The activated fuel pin being inspected in the detector is oscillated repeatedly over a distance equal to the spacing between adjacent detector elements, thereby multiplying the effective time available for detecting radiation emissions from the activated fuel pin.

  12. MAVEN Observations of Magnetic Flux Ropes with a Strong Field Amplitude in the Martian Magnetosheath During the ICME Passage on 8 March 2015

    Science.gov (United States)

    Hara, Takuya; Luhmann, Janet G.; Halekas, Jasper S.; Espley, Jared R.; Seki, Kanako; Brain, David A.; Hasegawa, Hiroshi; McFadden, James P.; Mitchell, David L.; Mazelle, Christian; hide

    2016-01-01

    We present initial results of strong field amplitude flux ropes observed by Mars Atmosphere and Volatile EvolutioN (MAVEN) mission around Mars during the interplanetary coronal mass ejection (ICME) passage on 8 March 2015. The observed durations were shorter than 5 s and the magnetic field magnitudes peaked above 80 nT, which is a few times stronger than those usually seen in the magnetosheath barrier. These are the first unique observations that MAVEN detected such flux ropes with a strong field at high altitudes (greater than 5000 km). Across these structures, MAVEN coincidentally measured planetary heavy ions with energies higher than a few keV. The spatial properties inferred from the Grad-Shafranov equation suggest that the speed of the structure can be estimated at least an order of magnitude faster than those previously reported quiet-time counterparts. Hence, the space weather event like the ICME passage can be responsible for generating the observed strong field, fast-traveling flux ropes.

  13. Strongly enhanced vortex pinning from 4 to 77 K in magnetic fields up to 31 T in 15 mol.% Zr-added (Gd, Y-Ba-Cu-O superconducting tapes

    Directory of Open Access Journals (Sweden)

    A. Xu

    2014-04-01

    Full Text Available Applications of REBCO coated conductors are now being developed for a very wide range of temperatures and magnetic fields and it is not yet clear whether vortex pinning strategies aimed for high temperature, low field operation are equally valid at lower temperatures and higher fields. A detailed characterization of the superconducting properties of a 15 mol. % Zr-added REBCO thin film made by metal organic chemical vapor deposition, from 4.2 to 77 K under magnetic fields up to 31 T is presented in this article. Even at a such high level of Zr addition, Tc depression has been avoided (Tc = 91 K, while at the same time an exceptionally high irreversibility field Hirr ≈ 14.8 T at 77 K and a remarkably high vortex pinning force density Fp ≈ 1.7 TN/m3 at 4.2 K have been achieved. We ascribe the excellent pinning performance at high temperatures to the high density (equivalent vortex matching field ∼7 T of self-assembled BZO nanorods, while the low temperature pinning force is enhanced by large additional pinning which we ascribe to strain-induced point defects induced in the REBCO matrix by the BZO nanorods. Our results suggest even more room for further performance enhancement of commercial REBCO coated conductors and point the way to REBCO coil applications at liquid nitrogen temperatures since the critical current density Jc(H//c characteristic at 77 K are now almost identical to those of fully optimized Nb-Ti at 4 K.

  14. Strongly enhanced vortex pinning from 4 to 77 K in magnetic fields up to 31 T in 15 mol.% Zr-added (Gd, Y)-Ba-Cu-O superconducting tapes

    Energy Technology Data Exchange (ETDEWEB)

    Xu, A; Delgado, L; Khatri, N; Liu, Y; Selvamanickam, V; Abraimov, D; Jaroszynski, J; Kametani, F; Larbalestier, DC

    2014-04-01

    Applications of REBCO coated conductors are now being developed for a very wide range of temperatures and magnetic fields and it is not yet clear whether vortex pinning strategies aimed for high temperature, low field operation are equally valid at lower temperatures and higher fields. A detailed characterization of the superconducting properties of a 15 mol.% Zr-added REBCO thin film made by metal organic chemical vapor deposition, from 4.2 to 77 K under magnetic fields up to 31 T is presented in this article. Even at a such high level of Zr addition, T-c depression has been avoided (T-c = 91 K), while at the same time an exceptionally high irreversibility field H-irr approximate to 14.8 T at 77 K and a remarkably high vortex pinning force density F-p approximate to 1.7 TN/m(3) at 4.2 K have been achieved. We ascribe the excellent pinning performance at high temperatures to the high density (equivalent vortex matching field similar to 7 T) of self-assembled BZO nanorods, while the low temperature pinning force is enhanced by large additional pinning which we ascribe to strain-induced point defects induced in the REBCO matrix by the BZO nanorods. Our results suggest even more room for further performance enhancement of commercial REBCO coated conductors and point the way to REBCO coil applications at liquid nitrogen temperatures since the critical current density J(c)(H//c) characteristic at 77 K are now almost identical to those of fully optimized Nb-Ti at 4 K. (C) 2014 Author(s).

  15. Fuel pin transfer tool

    International Nuclear Information System (INIS)

    Randazza, J. B.

    1984-01-01

    A fuel pin transfer tool has a tubular housing of sufficient length to enable it to be suspended in a body of water in which a fuel pin assembly is submerged with the upper end of the housing above the water and with the tool in vertical alignment with a selected fuel pin from which the lower end of the tool is closely spaced. The housing has a cylinder spaced from its ends in which there is a piston having a tubular piston rod extending slidably through both ends of the cylinder. An actuator, the control for which has first and second positions, is fixed on the upper end of the piston rod and has a member extending freely downwardly therethrough which on short downward travel, resulting when the control is in its second position, effects the pin-releasing position of a latching device secured to the lower end of the piston rod. The pin-releasing position is held until the control is returned to its first position with the latching device held in its pin-gripping position until the control is again in its second position. When the piston is in its low position and the control is in its second position, the selected pin may then be gripped by the latching device when the control is in its first position

  16. PINS Spectrum Identification Guide

    Energy Technology Data Exchange (ETDEWEB)

    A.J. Caffrey

    2012-03-01

    The Portable Isotopic Neutron Spectroscopy—PINS, for short—system identifies the chemicals inside munitions and containers without opening them, a decided safety advantage if the fill chemical is a hazardous substance like a chemical warfare agent or an explosive. The PINS Spectrum Identification Guide is intended as a reference for technical professionals responsible for the interpretation of PINS gamma-ray spectra. The guide is divided into two parts. The three chapters that constitute Part I cover the science and technology of PINS. Neutron activation analysis is the focus of Chapter 1. Chapter 2 explores PINS hardware, software, and related operational issues. Gamma-ray spectral analysis basics are introduced in Chapter 3. The six chapters of Part II cover the identification of PINS spectra in detail. Like the PINS decision tree logic, these chapters are organized by chemical element: phosphorus-based chemicals, chlorine-based chemicals, etc. These descriptions of hazardous, toxic, and/or explosive chemicals conclude with a chapter on the identification of the inert chemicals, e.g. sand, used to fill practice munitions.

  17. Twofold reduction of phosphofructokinase activity in Lactococcus lactis results in strong decreases in growth rate and in glycolytic flux

    DEFF Research Database (Denmark)

    Andersen, Heidi Winterberg; Solem, Christian; Hammer, Karin

    2001-01-01

    reduced. Surprisingly, the mutants still showed homolactic fermentation, which indicated that the limitation was different from standard glucose-limited conditions, One explanation could be that the reduced activity of phosphofructokinase resulted in the accumulation of sugar-phosphates. Indeed, when one...... kinase and lactate dehydrogenase remained closer to the wild-type level. In defined medium supplemented with glucose, the growth rate of the mutants was reduced to 57 to 70% of wild-type levels and the glycolytic flux was reduced to 62 to 76% of wild-type levels. In complex medium growth was even further...... of the mutants was starved for glucose in glucose-limited chemostat, the growth rate could gradually be increased to 195% of the growth fate observed in glucose-saturated batch culture, suggesting that phosphofructokinase does affect the concentration of upstream metabolites. The pools of glucose-6- phosphate...

  18. A pin by pin microscopic depletion scheme using an homogeneous core calculation with pin-power reconstruction

    International Nuclear Information System (INIS)

    Hoareau, F.; Fliscounakis, M.; Couyras, D.; Guillo, M.; Pora, Y.

    2009-01-01

    EDF/R and D is currently developing a new calculation scheme based on the transport-Simplified P n (SP n ) approach. The lattice code used is the CEA deterministic code APOLLO2, while the core code COCAGNE is currently under development at EDF R and D. This paper presents a new calculation scheme aimed at computing the pin by pin isotopic concentrations of fuel assemblies. This new scheme is based on homogeneous calculations and the use of the pin-power reconstruction method already implemented in COCAGNE. Indeed, this dehomogenization technique can supply the core code with an approximate pin by pin flux. The former is a necessary input for the microscopic depletion solver of COCAGNE. In order to validate this new microscopic depletion scheme, two kind of tests were performed. Firstly, direct comparisons with APOLLO2 results were made on the depletion calculation of a fuel assembly. It is shown that isotopic concentrations and the multiplication factor (keff) obtained by COCAGNE are consistent with APOLLO2 results. Secondly, the new scheme was compared with the existing calculation procedure of COCAGNE, that is heterogeneous calculations coupled with the microscopic depletion solver. The second test indicates that the new procedure gives also fairly accurate results. (author)

  19. Sticky pin mounting

    OpenAIRE

    Lilja, David

    2016-01-01

    The study was conducted at Volvo Arvika were pins sometimes are sticky to mount during assembly of wheel loaders. This causes problems regarding ergonomic, quality, cost and productivity. Due to deviations in tolerances, defects and errors, assemblers are forced to use equipment such as sledgehammers to mount the pins. The purpose of this study is to achieve and assembly process which meets Volvo´s criteria’s. By investigation the flows for frames at Volvo Arvika, defects and errors were disc...

  20. Enhancement of the point defect pinning effect in Mo-doped Bi2212 single crystals of reduced anisotropy

    CERN Document Server

    Han, S H; Dai, Y; Zhang, Y; Zhang, H; Zhao, Y

    2002-01-01

    High quality Bi sub 2 Sr sub 2 CaCu sub 2 sub - sub x Mo sub x O sub y (x = 0, 0.01 and 0.02) single crystals have been grown by a self-flux method in a horizontal temperature gradient and their flux pinning and irreversibility behaviour have been investigated. The irreversibility lines of the undoped and Mo-doped Bi2212 crystals have been greatly improved by reducing the anisotropy parameter gamma. However, this improvement is much more pronounced for Mo-doped crystals than for the undoped ones. The peak effect of magnetization loops also changes with both Mo-doping and gamma. The results provide strong evidence that the point defect pinning served by Mo is greatly enhanced when the anisotropy of the system is reduced.

  1. Strongly enhanced vortex pinning from 4 to 77 K in magnetic fields up to 31 T in 15 mol.% Zr-added (Gd, Y)-Ba-Cu-O superconducting tapes

    OpenAIRE

    A. Xu; L. Delgado; N. Khatri; Y. Liu; V. Selvamanickam; D. Abraimov; J. Jaroszynski; F. Kametani; D. C. Larbalestier

    2014-01-01

    Applications of REBCO coated conductors are now being developed for a very wide range of temperatures and magnetic fields and it is not yet clear whether vortex pinning strategies aimed for high temperature, low field operation are equally valid at lower temperatures and higher fields. A detailed characterization of the superconducting properties of a 15 mol. % Zr-added REBCO thin film made by metal organic chemical vapor deposition, from 4.2 to 77 K under magnetic fields up to 31 T is presen...

  2. PINS-3X Operations

    Energy Technology Data Exchange (ETDEWEB)

    E.H. Seabury

    2013-09-01

    Idaho National Laboratory’s (INL’s) Portable Isotopic Neutron Spectroscopy System (PINS) non-intrusively identifies the chemical fill of munitions and sealed containers. The PINS-3X variant of the system is used to identify explosives and uses a deuterium-tritium (DT) electronic neutron generator (ENG) as the neutron source. Use of the system, including possession and use of the neutron generator and shipment of the system components requires compliance with a number of regulations. This report outlines some of these requirements as well as some of the requirements in using the system outside of INL.

  3. Pinning Down versus Density

    OpenAIRE

    Juhász, István; Soukup, Lajos; Szentmiklóssy, Zoltán

    2015-01-01

    The pinning down number $ {pd}(X)$ of a topological space $X$ is the smallest cardinal $\\kappa$ such that for any neighborhood assignment $U:X\\to \\tau_X$ there is a set $A\\in [X]^\\kappa$ with $A\\cap U(x)\

  4. Lever-Arm Pin Puller

    Science.gov (United States)

    Macmartin, Malcolm

    1994-01-01

    Mechanism holds retaining pins in place except when actuated to release pins quickly. Mechanism is integral part of cover designed to be removed with simple downward motion of hand. Before removal, mechanism secures cover in place. After removal, mechanism holds retaining pins for reuse.

  5. Nanowall pinning for enhanced pinning force in YBCO films with nanofabricated structures

    Energy Technology Data Exchange (ETDEWEB)

    Palau, A.; Rouco, V.; Luccas, R.F.; Obradors, X.; Puig, T., E-mail: teresa.puig@icmab.es

    2014-11-15

    Highlights: • High resolution lithography techniques to fabricate artificial pinning centres in high temperature superconductors. • Enhanced critical currents of YBCO films with engineered nanofabricated structures. • Controlled nano-walls with weakened superconductivity acting as strong pinning centres. - Abstract: High resolution nanofabrication tools (Focused Ion Beam and Electron Beam Lithography) have been used to fabricate nano-metric milled structures in high critical current YBCO thin films able to further increase their vortex pinning capabilities. We have demonstrated that pinning forces at 77 K and 3 T are increased by a 70–80% by proper nanostructure designs. Model systems with linear trenches and triangular blind antidots of different sizes, distribution and density have been generated and studied. We demonstrate that specific milled nanostructures can increase the total current through the system at expenses of a limited decrease of cross section. We have identified the length of fabricated nano-walls as the main parameter controlling the pinning potential of nanostructures and thus defined the optimised milling conditions and nanostructure morphology to maximise pinning efficiency.

  6. Vortex Avalanches with Periodic Arrays of Pinning Sites

    Science.gov (United States)

    Abbas, J.; Heckel, T.; Kakalios, J.

    2001-03-01

    Numerical simulations by Nori and co-workers of dynamical phase transitions for magnetic vortices in type II superconductors when the defects which act as pinning sites are arranged in a periodic array have found a dramatic non-linear relationship between vortex voltage and driving current.2,4 In order to experimentally test the predictions of these simulations, a macroscopic physical analog of an array of flux vortices in the presense of an ordered lattice of pinning sites has been constructed. This simple table-top experimental system consists of conventional household magnets, arranged in an ordered grid (serving as the lattice of fixed pinning centers). A plexiglass sheet is positioned above these fixed magnets, and another collection of magnets (representing the magnetic flux vortices), oriented so that they are attracted to the fixed magnets are placed on top of the sheet. The entire apparatus is then tilted to a given angle (the analog of the driving voltage) and the velocity of the avalanching magnets is recorded using the induced voltage in a pick-up coil. By varying the ratio of movable magnets to fixed pinning magnets, the filling fraction can be adjusted, as can the pinning strength, by adjusting the separation of the plexiglass sheet between the fixed and movable magnets. The velocity of the avalanching magnets as the filling fraction is varied displays a jamming transition, with a non-trivial dependence on the pinning strength of the lattice of fixed magnets below the sheet.

  7. Nuclear fuel pin

    International Nuclear Information System (INIS)

    Hartley, Kenneth; Moulding, T.L.J.; Rostron, Norman.

    1979-01-01

    Fuel pin for use in fast breeder nuclear reactors containing fissile and fertile areas of which the fissile and fertile materials do not mix. The fissile material takes the shape of large and small diameter microspheres (the small diameter microspheres can pass through the interstices between the large microspheres). The barrier layers being composed of microspheres with a diameter situated between those of the large and small microspheres ensure that the materials do not mix [fr

  8. Critical currents in quasiperiodic pinning arrays: chains and Penrose lattices.

    Science.gov (United States)

    Misko, Vyacheslav; Savel'ev, Sergey; Nori, Franco

    2005-10-21

    We study the critical depinning current Jc versus the applied magnetic flux Phi, for quasiperiodic (QP) chains and 2D arrays of pinning centers placed on the nodes of a fivefold Penrose lattice. In QP chains, the peaks in Jc(Phi) are determined by a sequence of harmonics of the long and short segments of the chain. The critical current Jc(Phi) has a remarkable self-similarity. In 2D QP pinning arrays, we predict analytically and numerically the main features of Jc(Phi), and demonstrate that the Penrose lattice of pinning sites provides an enormous enhancement of Jc(Phi), even compared to triangular and random pinning site arrays. This huge increase in Jc(Phi) could be useful for applications.

  9. Vortex lattice ordering in the flux flow state of Nb thin films

    International Nuclear Information System (INIS)

    Grimaldi, Gaia; Leo, Antonio; Nigro, Angela; Pace, Sandro

    2010-01-01

    We measure current-voltage characteristics at high driving currents for different magnetic fields and temperatures in Nb thin films of rather strong pinning. In a definite range of the B-T phase diagram we find that a current induced transition occurs in the flux flow motion of the vortex lattice, namely a dynamic ordering (DO). Contrary to the case of weaker pinning materials, DO is observed only at low fields, due to the stronger intrinsic disorder that can deform plastically the moving vortex lattice even for small applied fields.

  10. The PIN-FORMED (PIN) protein family of auxin transporters.

    Science.gov (United States)

    Krecek, Pavel; Skupa, Petr; Libus, Jirí; Naramoto, Satoshi; Tejos, Ricardo; Friml, Jirí; Zazímalová, Eva

    2009-01-01

    The PIN-FORMED (PIN) proteins are secondary transporters acting in the efflux of the plant signal molecule auxin from cells. They are asymmetrically localized within cells and their polarity determines the directionality of intercellular auxin flow. PIN genes are found exclusively in the genomes of multicellular plants and play an important role in regulating asymmetric auxin distribution in multiple developmental processes, including embryogenesis, organogenesis, tissue differentiation and tropic responses. All PIN proteins have a similar structure with amino- and carboxy-terminal hydrophobic, membrane-spanning domains separated by a central hydrophilic domain. The structure of the hydrophobic domains is well conserved. The hydrophilic domain is more divergent and it determines eight groups within the protein family. The activity of PIN proteins is regulated at multiple levels, including transcription, protein stability, subcellular localization and transport activity. Different endogenous and environmental signals can modulate PIN activity and thus modulate auxin-distribution-dependent development. A large group of PIN proteins, including the most ancient members known from mosses, localize to the endoplasmic reticulum and they regulate the subcellular compartmentalization of auxin and thus auxin metabolism. Further work is needed to establish the physiological importance of this unexpected mode of auxin homeostasis regulation. Furthermore, the evolution of PIN-based transport, PIN protein structure and more detailed biochemical characterization of the transport function are important topics for further studies.

  11. Dynamique de la régénération naturelle chez le pin sylvestre, Pinus sylvestris L. : impacts de la structure des peuplements et des flux de gènes à différentes échelles spatiales sur la diversité génétique

    OpenAIRE

    Aspe, Pascal

    2009-01-01

    La phase de renouvellement constitue l’étape clé de la transmission du patrimoine génétique d’un peuplement forestier et du maintien de sa diversité génétique. Son succès est conditionné par la production de pollen et de graines. Cette thèse s’intéresse à l’impact de la structure des peuplements reproducteurs à différentes échelles spatiales sur les flux de gènes lors de régénérations naturelles de pin sylvestre (Pinus sylvestris L.). Elle identifie les principaux déterminants de la productio...

  12. Magnetic nanoparticles in MgB2: Vortex pinning, pair breaking and connectivity

    Science.gov (United States)

    Babić, Emil; Novosel, Nikolina; Pajić, Damir; Galić, Stipe; Zadro, Krešo; Drobac, Đuro

    2016-02-01

    The results indicating magnetic flux pinning in MgB2 wires doped with three types of magnetic nanoparticles (MNP) are reported. The magnetic state of MNPs, both as-prepared and inside the MgB2 core, was determined with magnetization and ac susceptibility measurements. The competition between detrimental influence of doping (reduced connectivity, pair breaking) and enhanced flux pinning leads to deterioration of electromagnetic properties of doped wires at high MNP content, whereas light doping causes an enhancement of critical current density, Jc, and/or irreversibility field, Birr, for all our MNPs. For Ni and dextrin coated NiFe2O4 MNPs the enhancement of Jc was comparable to that achieved with the best nonmagnetic dopands. Detailed analysis indicates the contribution of magnetic flux pinning including the matching effects in flux pinning on MNPs.

  13. Pinned vorticity in rotating superfluids, with application to neutron stars

    International Nuclear Information System (INIS)

    Pines, D.; Shaham, J.; Alpar, M.A.; Anderson, P.W.

    1981-01-01

    The dynamic consequences of the existence of pinned vorticity in a rotating superfluid are studied by means of a simple model: the behavior of a rotating cylinder which contains a uniform region of either weakly or strongly pinned vorticity and which is being spun up or spun down by an external torque. It is shown that in the case of strong pinning, spin down can lead to periodic jumps (glitches) in the rotation frequency of the cylinder, followed by quasi-oscillatory relaxation, while in the case of weak pinning no glitches occur unless the cylinder is shaken so violently that vortices unpin. We conclude that the giant glitches and post-glitch behavior observed in the Vela pulsar may be explained by the sudden release of some 10% of the strongly pinned vortices in the neutron crust every few years as a result of pulsar spin down. We further suggest that the post-glitch behavior observed in the Crab pulsar can be explained if the macroglitches represent vorticity jumps induced by small starquakes in the weakly pinned vortex region expected in the crust of a young neutron star, and that the differences in ''glitch'' behavior of the Crab, Vela, and older pulsars may be explained on evolutionary grounds. (author)

  14. Development of 3D pseudo pin-by-pin calculation methodology in ANC

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, B.; Mayhue, L.; Huria, H.; Ivanov, B. [Westinghouse Electric Company LLC, 1000 Westinghouse Drive, Cranberry, PA 16066 (United States)

    2012-07-01

    Advanced cores and fuel assembly designs have been developed to improve operational flexibility, economic performance and further enhance safety features of nuclear power plants. The simulation of these new designs, along with strong heterogeneous fuel loading, have brought new challenges to the reactor physics methodologies currently employed in the industrial codes for core analyses. Control rod insertion during normal operation is one operational feature in the AP1000{sup R} plant of Westinghouse next generation Pressurized Water Reactor (PWR) design. This design improves its operational flexibility and efficiency but significantly challenges the conventional reactor physics methods, especially in pin power calculations. The mixture loading of fuel assemblies with significant neutron spectrums causes a strong interaction between different fuel assembly types that is not fully captured with the current core design codes. To overcome the weaknesses of the conventional methods, Westinghouse has developed a state-of-the-art 3D Pin-by-Pin Calculation Methodology (P3C) and successfully implemented in the Westinghouse core design code ANC. The new methodology has been qualified and licensed for pin power prediction. The 3D P3C methodology along with its application and validation will be discussed in the paper. (authors)

  15. Development of 3D pseudo pin-by-pin calculation methodology in ANC

    International Nuclear Information System (INIS)

    Zhang, B.; Mayhue, L.; Huria, H.; Ivanov, B.

    2012-01-01

    Advanced cores and fuel assembly designs have been developed to improve operational flexibility, economic performance and further enhance safety features of nuclear power plants. The simulation of these new designs, along with strong heterogeneous fuel loading, have brought new challenges to the reactor physics methodologies currently employed in the industrial codes for core analyses. Control rod insertion during normal operation is one operational feature in the AP1000 R plant of Westinghouse next generation Pressurized Water Reactor (PWR) design. This design improves its operational flexibility and efficiency but significantly challenges the conventional reactor physics methods, especially in pin power calculations. The mixture loading of fuel assemblies with significant neutron spectrums causes a strong interaction between different fuel assembly types that is not fully captured with the current core design codes. To overcome the weaknesses of the conventional methods, Westinghouse has developed a state-of-the-art 3D Pin-by-Pin Calculation Methodology (P3C) and successfully implemented in the Westinghouse core design code ANC. The new methodology has been qualified and licensed for pin power prediction. The 3D P3C methodology along with its application and validation will be discussed in the paper. (authors)

  16. Synchronizability on complex networks via pinning control

    Indian Academy of Sciences (India)

    article/fulltext/pram/080/04/0593-0606 ... Numerical simulations show that different pinning strategies have different pinning synchronizability on the same complex network, and the synchronizability with pinning control is consistent with one ...

  17. Liquid-metal pin-fin pressure drop by correlation in cross flow

    International Nuclear Information System (INIS)

    Wang, Zhibi; Kuzay, T.M.; Assoufid, L.

    1994-01-01

    The pin-fin configuration is widely used as a heat transfer enhancement method in high-heat-flux applications. Recently, the pin-fin design with liquid-metal coolant was also applied to synchrotron-radiation beamline devices. This paper investigates the pressure drop in a pin-post design beamline mirror with liquid gallium as the coolant. Because the pin-post configuration is a relatively new concept, information in literature about pin-post mirrors or crystals is rare, and information about the pressure drop in pin-post mirrors with liquid metal as the coolant is even more sparse. Due to this the authors considered the cross flow in cylinder-array geometry, which is very similar to that of the pin-post, to examine the pressure drop correlation with liquid metals over pin fins. The cross flow of fluid with various fluid characteristics or properties through a tube bank was studied so that the results can be scaled to the pin-fin geometry with liquid metal as the coolant. Study lead to two major variables to influence the pressure drop: fluid properties, viscosity and density, and the relative length of the posts. Correlation of the pressure drop between long and short posts and the prediction of the pressure drop of liquid metal in the pin-post mirror and comparison with an existing experiment are addressed

  18. Critical Currents in Quasiperiodic Pinning Arrays: Chains and Penrose Lattices

    OpenAIRE

    Misko, V. R.; Savel'ev, Sergey; Nori, Franco

    2005-01-01

    We study the critical depinning current Jc versus the applied magnetic flux Phi, for quasiperiodic (QP) chains and 2D arrays of pinning centers placed on the nodes of a five-fold Penrose lattice. In QP chains, the peaks in Jc(Phi) are determined by a sequence of harmonics of the long and short segments of the chain. The critical current Jc(Phi) has a remarkable self-similarity. In 2D QP pinning arrays, we predict analytically and numerically the main features of Jc(Phi), and demonstrate that ...

  19. Pinning and irreversibility in superconducting bulk MgB{sub 2} with added nanodiamonds

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Anurag [Superconductivity and Cryogenics Division, National Physical Laboratory (CSIR), New Delhi-110012 (India); Narlikar, A V, E-mail: anurag@mail.nplindia.ernet.i [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore-452017, MP (India)

    2009-12-15

    Resistance, R(T), and magnetization, M(B), studies on superconducting bulk MgB{sub 2} samples containing nanodiamonds (ND) as additives (wt% of ND: x = 0%, 1%, 3%, 5%, 7% and 10%) were recently published in two articles (Vajpayee et al 2007 Supercond. Sci. Technol. 20 S155, Vajpayee et al 2008 J. Appl. Phys. 103 07C708). The main observations reported were significant improvements in the critical current density J{sub c}(B), irreversibility line B{sub irr}(T) and upper critical field B{sub c2}(T) with ND addition. However, a closer look shows that as regards the potential of this technologically important material at higher magnetic fields and temperatures, there is still a lot of room for improvement. With that in mind we revisit the R(T) and M(B) data and analyze them, in the present work. We show that, despite ND addition, J{sub c} depends strongly on B in the high field region and tends to vanish at irreversibility lines that lie deep, i.e. at around 0.3 B{sub c2}(T), in the B-T phase diagram. The irreversibility lines, determined by R(T){yields}0 in the presence of B, are found to lie at around 0.5 B{sub c2}(T) in the phase diagram. These results for pinning and irreversibility lines are discussed in the light of various models such as those of surface sheath superconductivity, magnetically introduced percolation in polycrystalline MgB{sub 2}, thermally assisted flux motion (TAFM) and a modified flux line shear mechanism. Our analysis hints at TAFM and weak pinning channels with distributed superconducting properties percolating in our samples determining the irreversibility and pinning properties.

  20. Resonant pinning spectroscopy with spin-vortex pairs

    Science.gov (United States)

    Holmgren, E.; Bondarenko, A.; Ivanov, B. A.; Korenivski, V.

    2018-03-01

    Vortex pairs in magnetic nanopillars with strongly coupled cores and pinning of one of the cores by a morphological defect, are used to perform resonant pinning spectroscopy, in which a microwave excitation applied to the nanopillar produces pinning or depinning of the cores only when the excitation is in resonance with the rotational or gyrational eigenmodes of the specific initial state of the core-core pair. The shift in the eigenmode frequencies between the pinned and depinned states is determined experimentally and explained theoretically, and illustrates the potential for multicore spin-vortex memory with resonant writing of information onto various stable vortex pair states. Further, it is shown how the same resonant spectroscopy techniques applied to a vortex pair can be used as a sensitive nanoscale probe for characterizing morphological defects in magnetic films.

  1. Local imaging of magnetic flux in superconducting thin films

    International Nuclear Information System (INIS)

    Shapoval, Tetyana

    2010-01-01

    Local studies of magnetic flux line (vortex) distribution in superconducting thin films and their pinning by natural and artificial defects have been performed using low-temperature magnetic force microscopy (LT-MFM). Taken a 100 nm thin NbN film as an example, the depinning of vortices from natural defects under the influence of the force that the MFM tip exerts on the individual vortex was visualized and the local pinning force was estimated. The good agreement of these results with global transport measurements demonstrates that MFM is a powerful and reliable method to probe the local variation of the pinning landscape. Furthermore, it was demonstrated that the presence of an ordered array of 1-μm-sized ferromagnetic permalloy dots being in a magneticvortex state underneath the Nb film significantly influences the natural pinning landscape of the superconductor leading to commensurate pinning effects. This strong pinning exceeds the repulsive interaction between the superconducting vortices and allows vortex clusters to be located at each dot. Additionally, for industrially applicable YBa 2 Cu 3 O 7-δ thin films the main question discussed was the possibility of a direct correlation between vortices and artificial defects as well as vortex imaging on rough as-prepared thin films. Since the surface roughness (droplets, precipitates) causes a severe problem to the scanning MFM tip, a nanoscale wedge polishing technique that allows to overcome this problem was developed. Mounting the sample under a defined small angle results in a smooth surface and a monotonic thickness reduction of the film along the length of the sample. It provides a continuous insight from the film surface down to the substrate with surface sensitive scanning techniques. (orig.)

  2. Local imaging of magnetic flux in superconducting thin films

    Energy Technology Data Exchange (ETDEWEB)

    Shapoval, Tetyana

    2010-01-26

    Local studies of magnetic flux line (vortex) distribution in superconducting thin films and their pinning by natural and artificial defects have been performed using low-temperature magnetic force microscopy (LT-MFM). Taken a 100 nm thin NbN film as an example, the depinning of vortices from natural defects under the influence of the force that the MFM tip exerts on the individual vortex was visualized and the local pinning force was estimated. The good agreement of these results with global transport measurements demonstrates that MFM is a powerful and reliable method to probe the local variation of the pinning landscape. Furthermore, it was demonstrated that the presence of an ordered array of 1-{mu}m-sized ferromagnetic permalloy dots being in a magneticvortex state underneath the Nb film significantly influences the natural pinning landscape of the superconductor leading to commensurate pinning effects. This strong pinning exceeds the repulsive interaction between the superconducting vortices and allows vortex clusters to be located at each dot. Additionally, for industrially applicable YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} thin films the main question discussed was the possibility of a direct correlation between vortices and artificial defects as well as vortex imaging on rough as-prepared thin films. Since the surface roughness (droplets, precipitates) causes a severe problem to the scanning MFM tip, a nanoscale wedge polishing technique that allows to overcome this problem was developed. Mounting the sample under a defined small angle results in a smooth surface and a monotonic thickness reduction of the film along the length of the sample. It provides a continuous insight from the film surface down to the substrate with surface sensitive scanning techniques. (orig.)

  3. Automated fuel pin loading system

    Science.gov (United States)

    Christiansen, D.W.; Brown, W.F.; Steffen, J.M.

    An automated loading system for nuclear reactor fuel elements utilizes a gravity feed conveyor which permits individual fuel pins to roll along a constrained path perpendicular to their respective lengths. The individual lengths of fuel cladding are directed onto movable transports, where they are aligned coaxially with the axes of associated handling equipment at appropriate production stations. Each fuel pin can be be reciprocated axially and/or rotated about its axis as required during handling steps. The fuel pins are inerted as a batch prior to welding of end caps by one of two disclosed welding systems.

  4. FFTF/IEM cell fuel pin weighing system

    International Nuclear Information System (INIS)

    Gibbons, P.W.

    1987-01-01

    The Interim Examination and Maintenance (IEM) cell in the Fast Flux Test Facility (FFTF) is used for remote disassembly of irradiated fuel and materials experiments. For those fuel experiments where the FFTF tag-gas detection system has indicated a fuel pin cladding breach, a weighing system is used in identifying that fuel pin with a reduced weight due to the escape of gaseous and volatile fission products. A fuel pin weighing machine, originally purchased for use in the Fuels and Materials Examination Facility (FMEF), was the basis for the IEM cell system. Design modifications to the original equipment were centered around adapting the machine to the differences between the two facilities and correcting deficiencies discovered during functional testing in the IEM cell mock-up

  5. Ordered Pinning Arrays with Tunable Geometry via Thermal Effects

    Science.gov (United States)

    Trastoy, Juan; Bernard, Rozenn; Briatico, Javier; Villegas, Javier E.; Malnou, Maxime; Bergeal, Nicolas; Lesueur, Jerome; Ulysse, Christian; Faini, Giancarlo

    2015-03-01

    We have used geometrically frustrated pinning arrays to create artificial vortex-ice. The pinning arrays are fabricated via ion irradiation of high-Tc superconducting films. These arrays present a very unique characteristic: the frustration can be reversibly switched on/off using temperature as a control knob, which allows stabilizing either a vortex-ice or a square vortex lattice. We have further investigated the thermal switching mechanism by studying the matching of the flux lattice to arrays that are incrementally deformed upon fabrication by introducing minute variations of the distance between pins. The array deformation exacerbates the thermal effects, leading to dramatic variations of the vortex distribution as a function of temperature. These results illustrate the strength of the temperature-induced reconfiguration effects, which may constitute a novel knob in fluxtronic devices based on vortex manipulation. Work supported by the French ANR MASTHER, the COST Action NanoSC, the Ville de Paris and the Galician Fundacion Barrie.

  6. Theory of activated glassy dynamics in randomly pinned fluids

    Science.gov (United States)

    Phan, Anh D.; Schweizer, Kenneth S.

    2018-02-01

    We generalize the force-level, microscopic, Nonlinear Langevin Equation (NLE) theory and its elastically collective generalization [elastically collective nonlinear Langevin equation (ECNLE) theory] of activated dynamics in bulk spherical particle liquids to address the influence of random particle pinning on structural relaxation. The simplest neutral confinement model is analyzed for hard spheres where there is no change of the equilibrium pair structure upon particle pinning. As the pinned fraction grows, cage scale dynamical constraints are intensified in a manner that increases with density. This results in the mobile particles becoming more transiently localized, with increases of the jump distance, cage scale barrier, and NLE theory mean hopping time; subtle changes of the dynamic shear modulus are predicted. The results are contrasted with recent simulations. Similarities in relaxation behavior are identified in the dynamic precursor regime, including a roughly exponential, or weakly supra-exponential, growth of the alpha time with pinning fraction and a reduction of dynamic fragility. However, the increase of the alpha time with pinning predicted by the local NLE theory is too small and severely so at very high volume fractions. The strong deviations are argued to be due to the longer range collective elasticity aspect of the problem which is expected to be modified by random pinning in a complex manner. A qualitative physical scenario is offered for how the three distinct aspects that quantify the elastic barrier may change with pinning. ECNLE theory calculations of the alpha time are then presented based on the simplest effective-medium-like treatment for how random pinning modifies the elastic barrier. The results appear to be consistent with most, but not all, trends seen in recent simulations. Key open problems are discussed with regard to both theory and simulation.

  7. Magnetic nanoparticles in MgB{sub 2}: Vortex pinning, pair breaking and connectivity

    Energy Technology Data Exchange (ETDEWEB)

    Babić, Emil [Department of Physics, Faculty of Science, University of Zagreb, Bijenička c. 32, HR-10000 Zagreb (Croatia); Novosel, Nikolina, E-mail: nnovosel@phy.hr [Department of Physics, Faculty of Science, University of Zagreb, Bijenička c. 32, HR-10000 Zagreb (Croatia); Pajić, Damir; Galić, Stipe; Zadro, Krešo [Department of Physics, Faculty of Science, University of Zagreb, Bijenička c. 32, HR-10000 Zagreb (Croatia); Drobac, Đuro [Institute of Physics, Bijenička c. 46, HR-10000 Zagreb (Croatia)

    2016-02-15

    The results indicating magnetic flux pinning in MgB{sub 2} wires doped with three types of magnetic nanoparticles (MNP) are reported. The magnetic state of MNPs, both as-prepared and inside the MgB{sub 2} core, was determined with magnetization and ac susceptibility measurements. The competition between detrimental influence of doping (reduced connectivity, pair breaking) and enhanced flux pinning leads to deterioration of electromagnetic properties of doped wires at high MNP content, whereas light doping causes an enhancement of critical current density, J{sub c}, and/or irreversibility field, B{sub irr}, for all our MNPs. For Ni and dextrin coated NiFe{sub 2}O{sub 4} MNPs the enhancement of J{sub c} was comparable to that achieved with the best nonmagnetic dopands. Detailed analysis indicates the contribution of magnetic flux pinning including the matching effects in flux pinning on MNPs. - Highlights: • Rigorous study of the effects of magnetic particles on superconductivity in MgB2 wires. • Detailed characterisation of magnetic state of nanoparticles embedded in MgB2 matrix. • Matching effects in pinning of vortices on magnetic nanoparticles • Consistent indications of possible contribution of magnetic pinning of vortices.

  8. Strong Evidence of Variable Micro-meteor Flux from Apollo 17 Samples Obtained at Shorty Crater and on the Light Mantle Avalanche at Taurus-Littrow

    Science.gov (United States)

    Schmitt, H. H.; Petro, N. E.

    2017-12-01

    Light-gray regolith overlying the orange and black pyroclastic ash (Schmitt, 2017) at Shorty Crater protected the ash from incorporation into surrounding basaltic regolith for 3.5 billion years (Tera and Wasserburg, 1976; Saito and Alexander, 1979). Inspection of LROC images indicate this regolith probably came from a 350 m diameter, degraded impact crater (Fitzgibbon Crater), about 1 km NNE of Shorty. This regolith was derived largely from basalt and spread over the ash deposit about 24 Myr (Eugster, et al., 1979, corrected for post-Shorty exposure) after the last ash eruption. Maturity indexes for light gray regolith samples 74441 and 74461 are about 8 (Morris, 1978) and agglutinate concentrations are 8% and 7.7% (Heiken and McKay, 1974), respectively. These values are inconsistent with the exposure and cycling of the light-gray regolith during 3.5 billion years in the lunar surface impact environment (i.e., the time between ash deposition and the light mantle avalanche). If agglutinate content and Is/FeO indexes largely reflect the cumulative effect of micro-meteor impacts, as generally concluded, the light-gray regolith formed in an environment with significantly less micro-meteor flux than that which has prevailed more recently. 14-18% of fragile, ropy glass in the light-gray regolith, as compared with meteor flux during development. The high recent micro-meteor flux appears to have existed for at least for the last 75 million years (Schmitt, et al., 2017), the estimated time using LROC-based crater frequency analysis (van der Bogert, et al., 2012) since the light mantle avalanche of South Massif regolith covered the light-gray regolith. New regolith on the light mantle appears to be developing a higher concentration of agglutinates and a higher maturity index relative to regolith in deeper portions of the unit. Light mantle avalanche samples 73141 (subsurface) and 73121 (near surface), have agglutinates at 32% and 42% and Is/FeO indexes of 48 and 78

  9. Intrinsic pinning in superconductors with extremely small coherence lengths

    International Nuclear Information System (INIS)

    Schimmele, L.; Kronmueller, H.; Teichler, H.

    1988-01-01

    By means of a Ginsburg-Landau-type theory which takes into account the discrete lattice structure the variation of the energy ('Peierls potential') of an isolated flux line is calculated when shifted relatively to the crystal lattice. In particular, a primitive cubic lattice is considered with a straight flux line, aligned parallel to a cubic axis. The resulting Peierls potential may lead to intrinsic pinning if the coherence length is smaller than about two nearest neighbour distances. The coherence lengths at low temperatures determined for the recently discovered high T c superconductors of the YBa 2 Cu 3 O 7 class come very close to this value so that intrinsic pinning might possibly be relevant for these superconductors. (author)

  10. Spatial chaotic behavior of vortices in type-II superconductors with different pinning strength

    Energy Technology Data Exchange (ETDEWEB)

    Lin, H.-T. [Faculty of Information Management, Cheng Shui University, Taiwan (China); Pan, M. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity R and D Center, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Cheng, C.H. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity R and D Center, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney (Australia); Cui, Y.J. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity R and D Center, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhao, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity R and D Center, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney (Australia)], E-mail: yzhao@swjtu.edu.cn

    2008-09-15

    Spatial chaotic character in systems where defects are arranged in periodic arrays has been investigated by computer simulation. Due to the high nonlinearity of the vortex-defect interaction, arrangement of the vortices in a periodic pinning array can be chaotic (glassy), depending on the vortex-defect interaction state and vortex-vortex interaction. Two types of disordered vortex states in the system are observed. The type-I disorder arises from the intrinsically chaotic nature of the nonlinear system, existing when the pinning disorder is low and the pinning strength is weak. The type-II disordered state is related to the pinning disorder, which is dominating when both the pinning disorder and the pinning strength are strong.

  11. Domain-growth kinetics and aspects of pinning: A Monte Carlo simulation study

    DEFF Research Database (Denmark)

    Castán, T.; Lindgård, Per-Anker

    1991-01-01

    By means of Monte Carlo computer simulations we study the domain-growth kinetics after a quench across a first-order line to very low and moderate temperatures in a multidegenerate system with nonconserved order parameter. The model is a continuous spin model relevant for martensitic...... transformations, surface reconstructions, and magnetic transitions. No external impurities are introduced, but the model has a number of intrinsic, annealable pinning mechanisms, which strongly influences the growth kinetics. It allows a study of pinning effects of three kinds: (a) pinning of domain walls...... by defects-this is found in effect to stop the growth, forming a metastable state at low temperatures T; (b) temporary pinning by stacking faults or zero-curvature domain walls; and (c) topological pinnings, which are also found to be temporary. These just slow down the growth. The pinning mechanisms...

  12. Spatial chaotic behavior of vortices in type-II superconductors with different pinning strength

    International Nuclear Information System (INIS)

    Lin, H.-T.; Pan, M.; Cheng, C.H.; Cui, Y.J.; Zhao, Y.

    2008-01-01

    Spatial chaotic character in systems where defects are arranged in periodic arrays has been investigated by computer simulation. Due to the high nonlinearity of the vortex-defect interaction, arrangement of the vortices in a periodic pinning array can be chaotic (glassy), depending on the vortex-defect interaction state and vortex-vortex interaction. Two types of disordered vortex states in the system are observed. The type-I disorder arises from the intrinsically chaotic nature of the nonlinear system, existing when the pinning disorder is low and the pinning strength is weak. The type-II disordered state is related to the pinning disorder, which is dominating when both the pinning disorder and the pinning strength are strong

  13. Neutron-diffraction investigations of flux-lines in superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Forgan, E.M. [Birmingham Univ. (United Kingdom); Lee, S.L. [Saint Andrews Univ. (United Kingdom); McKPaul, D. [Warwick Univ., Coventry (United Kingdom); Mook, H.A. [Oak Ridge National Lab., TN (United States); Cubitt, R. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1997-04-01

    SANS has proved an extremely useful tool for investigating flux-line structures within the bulk of superconductors. With high-T{sub c} materials, the scattered intensities are weak, but careful measurements are giving important new information about flux lattices, flux pinning and flux-lattice melting. (author). 10 refs.

  14. Influence of magnetic domain landscape on the flux dynamics in superconductor/ferromagnet bilayers

    Science.gov (United States)

    Adamus, Z.; Cieplak, Marta Z.; Kończykowski, M.; Zhu, L. Y.; Chien, C. L.

    2016-02-01

    We use a line of miniature Hall sensors to study the influence of the magnetic domain distribution on the flux dynamics in superconductor/ferromagnet bilayers. Two bilayers are built of a ferromagnetic Co/Pt multilayer with perpendicular magnetic anisotropy and a superconducting Nb layer, with the insulating layer in-between to avoid proximity effect. The magnetic domain patterns of various geometries are reversibly predefined in the Co/Pt multilayers using the appropriate magnetization procedure. The Pt thickness is different in the two bilayers, resulting in different width and length of the domains, which profoundly affects vortex dynamics. We show that narrow short domains lead to strong confinement of vortices at the sample edge, while narrow elongated domains of uniform width induce smaller confinement and easy vortex entry. Large enhancement of flux pinning and critical current density, by a factor of more than 7, is observed in the last case, while the former results in smaller enhancement. When domains are wide, the disorder in the domain widths becomes beneficial for larger enhancement of pinning, while more uniform distribution of domain widths results in a precipitous drop of the enhancement. The analysis of these results suggests that with increasing domain width, a transition occurs from vortex chains pinned by narrow domains to disordered triangular vortex lattice pinned by a maze of multiply interconnected magnetic domains.

  15. Enhanced pinning in superconducting thin films with graded pinning landscapes

    Science.gov (United States)

    Motta, M.; Colauto, F.; Ortiz, W. A.; Fritzsche, J.; Cuppens, J.; Gillijns, W.; Moshchalkov, V. V.; Johansen, T. H.; Sanchez, A.; Silhanek, A. V.

    2013-05-01

    A graded distribution of antidots in superconducting a-Mo79Ge21 thin films has been investigated by magnetization and magneto-optical imaging measurements. The pinning landscape has maximum density at the sample border, decreasing linearly towards the center. Its overall performance is noticeably superior than that for a sample with uniformly distributed antidots: For high temperatures and low fields, the critical current is enhanced, whereas the region of thermomagnetic instabilities in the field-temperature diagram is significantly suppressed. These findings confirm the relevance of graded landscapes on the enhancement of pinning efficiency, as recently predicted by Misko and Nori [Phys. Rev. B 85, 184506 (2012)].

  16. Controlling the flux dynamics in superconductors by nanostructured magnetic arrays

    Science.gov (United States)

    Kapra, Andrey

    In this thesis we investigate theoretically how the critical current jc of nano-engineered mesoscopic superconducting film can be improved and how one can control the dynamics of the magnetic flux, e.g., the transition from flux-pinned to flux-flow regime, using arrays of magnetic nanostructures. In particularly we investigate: (1) Vortex transport phenomena in superconductors with deposited ferromagnetic structures on top, and the influence of the sample geometry on the critical parameters and on the vortex configurations. Changing geometry of the magnetic bars and magnetization of the bars will affect the critical current jc of the superconducting film. Such nanostructured ferromagnets strongly alter the vortex structure in its neighborhood. The influence of geometry, position and magnetization of the ferromagnet (single bar or regular lattice of the bars) on the critical parameters of the superconductor is investigated. (2) Effect of flux confinement in narrow superconducting channels with zigzag-shaped banks: the flux motion is confined in the transverse (perpendicular) direction of a diamond-cell-shape channel. The matching effect for the magnetic flux is found in the system relevantless of boundary condition. We discuss the dynamics of vortices in the samples and vortex pattern formation in the channel. We show how the inclusion of higher-Tc superconductor into the sample can lead to enhanced properties of the system. By adding an external driving force, we study the vortex dynamics. The different dynamic regimes are discussed. They allowed an effective control of magnetic flux in superconductors.

  17. PinBus Interface Design

    Energy Technology Data Exchange (ETDEWEB)

    Hammerstrom, Donald J.; Adgerson, Jewel D.; Sastry, Chellury; Pratt, Richard M.; Pratt, Robert G.

    2009-12-30

    On behalf of the U.S. Department of Energy, PNNL has explored and expanded upon a simple control interface that might have merit for the inexpensive communication of smart grid operational objectives (demand response, for example) to small electric end-use devices and appliances. The approach relies on bi-directional communication via the electrical voltage states of from one to eight shared interconnection pins. The name PinBus has been suggested and adopted for the proposed interface protocol. The protocol is defined through the presentation of state diagrams and the pins’ functional definitions. Both simulations and laboratory demonstrations are being conducted to demonstrate the elegance and power of the suggested approach. PinBus supports a very high degree of interoperability across its interfaces, allowing innumerable pairings of devices and communication protocols and supporting the practice of practically any smart grid use case.

  18. MONJU fuel pin performance analysis

    International Nuclear Information System (INIS)

    Kitagawa, H.; Yamanaka, T.; Hayashi, H.

    1979-01-01

    Monju fuel pin has almost the same properties as other LMFBR fuel pins, i.e. Phenix, PFR, CRBR, but would be irradiated under severe conditions: maximum linear heat rate of 381 watt/cm, hot spot cladding temperature of 675 deg C, peak burnup of 131,000 MWd/t, peak fluence (E greater than 0.1 MeV) of 2.3 10 23 n/cm 2 . In order to understand in-core performance of Monju fuel pin, its thermal and mechanical behaviour was predicted using the fast running performance code SIMPLE. The code takes into account pellet-cladding interaction due to thermal expansion and swelling, gap conductance, structural changes of fuel pellets, fission product gas release with burnup and temperature increase, swelling and creep of fuel pellets, corrosion of cladding due to sodium flow and chemical attack by fission products, and cumulative damage of the cladding due to thermal creep

  19. Collective-pinning properties of superconducting a-NbxGe and a-MoxSi films

    International Nuclear Information System (INIS)

    Woerdenweber, R.

    1987-01-01

    This thesis describes a study of superconducting flux pinning in amorphous NbGe and MoSi films of various compositions and thickness. Amorphous NbGe and MoSi alloys belong to the weak-coupling type-II superconductors in the extreme dirty limit. This feature enables to determine several important superconducting parameters from well-known theoretical expressions. It is also responsible for the weak pinning, which is necessary to observe the two-dimensional collective pinning properties according to the Larkin-Ovchinnikov theory. (Auth.)

  20. Improved pinning regime by energetic ions using reduction of pinning potential

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Roy; Gandini, Alberto; Sawh, Ravi-Persad; Parks, Drew; Mayes, Bill

    2003-05-15

    When ion damage is used to create pinning centers, full columnar pinning centers provide the largest pinning potential, U{sub pin}, but not the greatest J{sub c} or pinned field, B{sub pin}. Some of the characteristics of columnar defects which limit J{sub c} and B{sub pin} are discussed, including reduction of percolation path, and the need for a larger number of columns of damage, for pinning, than are usually estimated. It is concluded that columnar pinning centers are limited to B{sub pin}<4 T, and also severely reduce J{sub c}. Evidence is reviewed that aligned damage, or broken-columnar pinning centers, described herein, can provide orders of magnitude higher J{sub c}, and higher pinned field, despite providing lower U{sub pin}. A pinning center morphology is discussed which utilizes multiple-in-line-damage (MILD). For, e.g., present day large grain HTS J{sub c}, obtainable by MILD pinning, is estimated to be of the order of 10{sup 6} A/cm{sup 2} at 77 K, even when crystal plane alignment and weak links are not improved. Pinned field is increased by over an order of magnitude. An experiment is proposed to confirm these observations, and to directly compare MILD to columnar pinning centers. It will also determine the optimum MILD structure. Other measurements of interest, made possible by the same data set, are described.

  1. Multicenter Study of Pin Site Infections and Skin Complications Following Pinning of Pediatric Supracondylar Humerus Fractures.

    Science.gov (United States)

    Combs, Kristen; Frick, Steven; Kiebzak, Gary

    2016-12-03

    Pediatric supracondylar humerus fractures are the most common elbow fractures in pediatric patients. Surgical fixation using pins is the primary treatment for displaced fractures. Pin site infections may follow supracondylar humerus fracture fixation; the previously reported incidence rate in the literature is 2.34%, but there is significant variability in reported incidence rates of pin site infection. This study aims to define the incidence rate and determine pre-, peri-, and postoperative factors that may contribute to pin site infection following operative reduction, pinning, and casting. A retrospective chart analysis was performed over a one-year period on patients that developed pin site infection. A cast care form was added to Nemours' electronic medical records (EMR) system (Epic Systems Corp., Verona, WI) to identify pin site infections for retrospective review. The cast care form noted any inflamed or infected pins. Patients with inflamed or infected pin sites underwent a detailed chart review. Preoperative antibiotic use, number and size of pins used, method of postoperative immobilization, pin dressings, whether postoperative immobilization was changed prior to pin removal, and length of time pins were in place was recorded. A total of 369 patients underwent operative reduction, pinning, and casting. Three patients developed a pin site infection. The pin site infection incidence rate was 3/369=0.81%. Descriptive statistics were reported for the three patients that developed pin site infections and three patients that developed pin site complications. Pin site infection development is low. Factors that may contribute to the development of pin site infection include preoperative antibiotic use, length of time pins are left in, and changing the cast prior to pin removal.

  2. Strong Links Between Teleconnections and Ecosystem Exchange Found at a Pacific Northwest Old-Growth Forest from Flux Tower and MODIS EVI Data

    Energy Technology Data Exchange (ETDEWEB)

    Wharton, S; Chasmer, L; Falk, M; Paw U, K T

    2009-03-12

    Variability in three Pacific teleconnection patterns are examined to see if net carbon exchange at a low-elevation, old-growth forest is affected by climatic changes associated with these periodicities. Examined are the Pacific Decadal Oscillation (PDO), Pacific/North American Oscillation (PNA) and El Nino-Southern Oscillation (ENSO). We use nine years of eddy covariance CO{sub 2}, H{sub 2}O and energy fluxes measured at the Wind River AmeriFlux site, Washington, USA and eight years of tower-pixel remote sensing data from the Moderate Resolution Imaging Spectroradiometer (MODIS) to address this question. We compute a new Composite Climate Index (CCI) based on the three Pacific Oscillations to divide the measurement period into positive- (2003 and 2005), negative- (1999 and 2000) and neutral-phase climate years (2001, 2002, 2004, 2006 and 2007). The forest transitioned from an annual net carbon sink (NEP = + 217 g C m{sup -2} year{sup -1}, 1999) to a source (NEP = - 100 g C m{sup -2} year{sup -1}, 2003) during two dominant teleconnection patterns. Net ecosystem productivity (NEP), water use efficiency (WUE) and light use efficiency (LUE) were significantly different (P < 0.01) during positive (NEP = -0.27 g C m{sup -2} day{sup -1}, WUE = 4.1 mg C/g H{sub 2}O, LUE = 0.94 g C MJ{sup -1}) and negative (NEP = +0.37 g C m{sup -2} day{sup -1}, WUE = 3.4 mg C/g H{sub 2}O, LUE = 0.83 g C MJ{sup -1}) climate phases. The CCI was linked to variability in the MODIS Enhanced Vegetation Index (EVI) but not to MODIS Fraction of absorbed Photosynthetically Active Radiation (FPAR). EVI was highest during negative climate phases (1999 and 2000) and was positively correlated with NEP and showed potential for using MODIS to estimate teleconnection-driven anomalies in ecosystem CO{sub 2} exchange in old-growth forests. This work suggests that any increase in the strength or frequency of ENSO coinciding with in-phase, low frequency Pacific oscillations (PDO and PNA) will likely increase

  3. Silicide Schottky Contacts to Silicon: Screened Pinning at Defect Levels

    Energy Technology Data Exchange (ETDEWEB)

    Drummond, T.J.

    1999-03-11

    Silicide Schottky contacts can be as large as 0.955 eV (E{sub v} + 0.165 eV) on n-type silicon and as large as 1.05 eV (E{sub c} {minus} 0.07 eV) on p-type silicon. Current models of Schottky barrier formation do not provide a satisfactory explanation of occurrence of this wide variation. A model for understanding Schottky contacts via screened pinning at defect levels is presented. In the present paper it is shown that most transition metal silicides are pinned approximately 0.48 eV above the valence band by interstitial Si clusters. Rare earth disilicides pin close to the divacancy acceptor level 0.41 eV below the conduction band edge while high work function silicides of Ir and Pt pin close to the divacancy donor level 0.21 eV above the valence band edge. Selection of a particular defect pinning level depends strongly on the relative positions of the silicide work function and the defect energy level on an absolute energy scale.

  4. Suspension scheme for fuel pin

    International Nuclear Information System (INIS)

    Butts, C.E.; Gray, H.C.

    1975-01-01

    A description is presented of a nuclear fuel pin suspension arrangement comprising, in combination, a rod; a first beam member connected to said rod at one end; a plurality of parallel-spaced slidable fuel support plates attached to said first beam member, the longitudinal axis of first beam member being perpendicular to the longitudinal axis of each of said fuel support plates, a first coupling means disposed along the length of the first beam member for permitting slidable fuel support plates parallel movement with respect to the longitudinal axis of said first beam member, a second coupling means located at one end of each of slidable fuel plates for slidably engaging first coupling means of first beam member, a second beam member connected to the other end of each of parallel-spaced slidable fuel support plates and providing an extension, second beam member being provided with a third coupling means disposed along the length of second beam member at one end thereof; and a plurality of fuel pins provided with a fourth coupling means located at one end of each fuel pin for slidably engaging third coupling means of second beam member to permit each fuel pin parallel movement with respect to the longitudinal axis of second beam member. (U.S.)

  5. Fuel pin bowing in CAGR

    International Nuclear Information System (INIS)

    Crossland, I.G.

    1982-01-01

    Some of the more important mechanisms by which pin bowing can occur in Advanced Gas Cooled Reactors are examined. These include creep relaxation of the stresses which occur when thermal bowing is restrained and asymmetric axial clad creep. The clad temperature changes which accompany such bowing are also investigated and the theoretical results briefly compared with the empirical behaviour. (author)

  6. Microstrip PIN diode microwave switch

    OpenAIRE

    Usanov, Dmitry A.; Skripal, A. V.; Kulikov, M. Yu.

    2011-01-01

    A possibility of creating narrow-band electrically controlled microwave breakers and switches with enhanced attenuation level in the blocking mode has been considered. The specified devices are based on the structure containing a short-circuited microstrip link with connected capacitor and the loop coupler, in the center of which is located a PIN diode.

  7. C-axis correlated pinning mechanism in vortex liquid and solid phases for Sm123 film with well-aligned BaHfO3 nanorods

    Science.gov (United States)

    Awaji, Satoshi; Tsuchiya, Yuji; Miura, Shun; Ichino, Yusuke; Yoshida, Yutaka; Matsumoto, Kaname

    2017-11-01

    Nanorods, which are nano-scaled columnar-shape precipitates, have recently been used to improve critical current density J c in magnetic fields for REBa2Cu3O y (RE123, RE: rare earth element) high temperature superconducting tapes/films. However, the flux pinning mechanism of the nanorod is not clear yet. We investigated the J c and resistivity ρ properties in detail and discussed the flux pinning properties on the basis of the flux pinning state diagram for high-quality Sm123 films with well-aligned 5.6 vol% BaHfO3 nanorods. Plateaus were observed in the field dependence of J c and ρ at high temperatures above the delocalization temperature. This suggests that nanorod pinning becomes effective in the vortex liquid phase and it grows up when the temperature decreases toward the delocalization temperature. In the ‘many-nanorod’ state in the high temperature region above the delocalization temperature, double peaks in the F p curves appear due to the coexistence of nanorod pinning and random pinning. At low temperatures below 70 K, however, the well-scaled F p curves at low fields and temperature dependent (non-scaled) normalized F p curves are observed. From detailed analysis using the cooperation model of the random and the correlated pinning centers, we found that nanorod pinning is dominant below the matching field and the cooperation between nanorod pinning and random pinning determines the high field J c properties above the matching field.

  8. Propagative Landau states and Fermi level pinning in carbon nanotubes.

    Science.gov (United States)

    Nanot, Sébastien; Avriller, Rémi; Escoffier, Walter; Broto, Jean-Marc; Roche, Stephan; Raquet, Bertrand

    2009-12-18

    We present strong evidence of Landau states formation in multiwalled carbon nanotubes with metallic or semiconducting outer shells, under magnetic fields as high as 60 T. Magnetoconductance data are found to converge to a gate-independent value for semiconducting shells, whereas for metallic shells, the Landau states introduce a strong reintroduction of backscattering and Fermi level pinning close to the charge neutrality point. Electronic band structure and transport calculations provide a consistent interpretation of the experimental data.

  9. Diagnosing Undersampling in Monte Carlo Eigenvalue and Flux Tally Estimates

    Energy Technology Data Exchange (ETDEWEB)

    Perfetti, Christopher M [ORNL; Rearden, Bradley T [ORNL

    2015-01-01

    This study explored the impact of undersampling on the accuracy of tally estimates in Monte Carlo (MC) calculations. Steady-state MC simulations were performed for models of several critical systems with varying degrees of spatial and isotopic complexity, and the impact of undersampling on eigenvalue and fuel pin flux/fission estimates was examined. This study observed biases in MC eigenvalue estimates as large as several percent and biases in fuel pin flux/fission tally estimates that exceeded tens, and in some cases hundreds, of percent. This study also investigated five statistical metrics for predicting the occurrence of undersampling biases in MC simulations. Three of the metrics (the Heidelberger-Welch RHW, the Geweke Z-Score, and the Gelman-Rubin diagnostics) are commonly used for diagnosing the convergence of Markov chains, and two of the methods (the Contributing Particles per Generation and Tally Entropy) are new convergence metrics developed in the course of this study. These metrics were implemented in the KENO MC code within the SCALE code system and were evaluated for their reliability at predicting the onset and magnitude of undersampling biases in MC eigenvalue and flux tally estimates in two of the critical models. Of the five methods investigated, the Heidelberger-Welch RHW, the Gelman-Rubin diagnostics, and Tally Entropy produced test metrics that correlated strongly to the size of the observed undersampling biases, indicating their potential to effectively predict the size and prevalence of undersampling biases in MC simulations.

  10. Self-shearing retentive pins: a laboratory evaluation of pin channel penetration before shearing.

    Science.gov (United States)

    Barkmeier, W W; Cooley, R L

    1979-09-01

    This laboratory study determined the depth reached by self-shearing pins in dentin pin channels. Pin channels were prepared with the self-limiting shoulder twist drill for each of the four systems tested. Mean channel depth reached for the various pin systems was: Stabilok (small), 2.31 mm; Stabilok (medium), 1.78 mm; Reten Pin, 1.40 mm; and TMS (Regular), 2.04 mm. A coparison was also made by calculating the mean percent of penetration in relation to the depth of prepared pin channel: Stabilok (small), 92.50%; Stabilok (medium), 63.62%; Reten Pin, 66.67%; and TMS (Regular) 81.75%.

  11. The PIN-FORMED (PIN) protein family of auxin transporters

    Czech Academy of Sciences Publication Activity Database

    Křeček, Pavel; Skůpa, Petr; Libus, Jiří; Naramoto, S.; Tejos, R.; Friml, J.; Zažímalová, Eva

    2009-01-01

    Roč. 10, č. 12 (2009), s. 249.1-249.11 ISSN 1474-760X R&D Projects: GA MŠk(CZ) LC06034; GA AV ČR KJB600380904; GA AV ČR(CZ) IAA601630703 Institutional research plan: CEZ:AV0Z50380511 Keywords : PIN protein family * auxin efflux carriers * auxin transport Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.626, year: 2009

  12. Phylogeny and molecular evolution analysis of PIN-FORMED 1 in angiosperm.

    Directory of Open Access Journals (Sweden)

    Pengkai Wang

    Full Text Available PIN-FORMED 1 (PIN1 is an important secondary transporter and determines the direction of intercellular auxin flow. As PIN1 performs the conserved function of auxin transport, it is expected that the sequence and structure of PIN1 is conserved. Therefore, we hypothesized that PIN1 evolve under pervasive purifying selection in the protein-coding sequences in angiosperm. To test this hypothesis, we performed detailed evolutionary analyses of 67 PIN1 sequences from 35 angiosperm species. We found that the PIN1 sequences are highly conserved within their transmembrane regions, part of their hydrophilic regions. We also found that there are two or more PIN1 copies in some of these angiosperm species. PIN1 sequences from Poaceae and Brassicaceae are representative of the modern clade. We identified 12 highly conserved motifs and a significant number of family-specific sites within these motifs. One family-specific site within Motif 11 shows a different residue between monocots and dicots, and is functionally critical for the polarity of PIN1. Likewise, the function of PIN1 appears to be different between monocots and dicots since the phenotype associated with PIN1 overexpression is opposite between Arabidopsis and rice. The evolution of angiosperm PIN1 protein-coding sequences appears to have been primarily driven by purifying selection, but traces of positive selection associated with sequences from certain families also seem to be present. We verified this observation by calculating the numbers of non-synonymous and synonymous changes on each branch of a phylogenetic tree. Our results indicate that the evolution of angiosperm PIN1 sequences involve strong purifying selection. In addition, our results suggest that the conserved sequences of PIN1 derive from a combination of the family-specific site variations and conserved motifs during their unique evolutionary processes, which is critical for the functional integrity and stability of these auxin

  13. Phylogeny and molecular evolution analysis of PIN-FORMED 1 in angiosperm.

    Science.gov (United States)

    Wang, Pengkai; Cheng, Tielong; Wu, Shuang; Zhao, Fangfang; Wang, Guangping; Yang, Liming; Lu, Mengzhu; Chen, Jinhui; Shi, Jisen

    2014-01-01

    PIN-FORMED 1 (PIN1) is an important secondary transporter and determines the direction of intercellular auxin flow. As PIN1 performs the conserved function of auxin transport, it is expected that the sequence and structure of PIN1 is conserved. Therefore, we hypothesized that PIN1 evolve under pervasive purifying selection in the protein-coding sequences in angiosperm. To test this hypothesis, we performed detailed evolutionary analyses of 67 PIN1 sequences from 35 angiosperm species. We found that the PIN1 sequences are highly conserved within their transmembrane regions, part of their hydrophilic regions. We also found that there are two or more PIN1 copies in some of these angiosperm species. PIN1 sequences from Poaceae and Brassicaceae are representative of the modern clade. We identified 12 highly conserved motifs and a significant number of family-specific sites within these motifs. One family-specific site within Motif 11 shows a different residue between monocots and dicots, and is functionally critical for the polarity of PIN1. Likewise, the function of PIN1 appears to be different between monocots and dicots since the phenotype associated with PIN1 overexpression is opposite between Arabidopsis and rice. The evolution of angiosperm PIN1 protein-coding sequences appears to have been primarily driven by purifying selection, but traces of positive selection associated with sequences from certain families also seem to be present. We verified this observation by calculating the numbers of non-synonymous and synonymous changes on each branch of a phylogenetic tree. Our results indicate that the evolution of angiosperm PIN1 sequences involve strong purifying selection. In addition, our results suggest that the conserved sequences of PIN1 derive from a combination of the family-specific site variations and conserved motifs during their unique evolutionary processes, which is critical for the functional integrity and stability of these auxin transporters

  14. Flux flow, pinning, and resistive behavior in superconducting networks

    International Nuclear Information System (INIS)

    Teitel, S.

    1993-10-01

    We have studied the behavior of fluctuation effects in superconducting systems using numerical simulations of XY and Coulomb gas models. The fluctuation of vortex lines in high temperature superconductors, in the presence of an external magnetic field, has been studied using a three dimensional XY model. We have continued earlier work and verified the existence of two distinct phase transitions in this model. As the vortex line lattice is heated, it melts first into a line liquid where superconductivity is destroyed for currents perpendicular to the applied magnetic field, but persists for currents parallel to the field. As heating continues, the thermal excitation of closed vortex line loops links all the lines together, leading to completely normal metal properties in all directions. Upon cooling of the vortex line liquid, we find that as the system width increases, one can get trapped into an entangled non-equilibrium state in which vortex line cuttings are frozen out on measurable nine scales. We have also continued simulations of the two dimensional Coulomb gas, as a model for vortex fluctuations in two dimensional arrays of Josephson junctions, and thin film superconductors. Our preliminary results support the accepted view of a Kosterlitz-Thouless melting of the vortex lattice, in the limit of a uniform continous film

  15. Flux Flow, Pinning, and Resistive Behavior in Superconducting Networks

    International Nuclear Information System (INIS)

    Stephen Teitel

    2005-01-01

    Numerical simulators are used to study the behavior of interacting quantized vortices and vortex lines in superconducting networks, films, and three dimensional bulk samples. An emphasis is on the explanation of the phenomenological behavior of the ''high-Tc'' copper-oxide superconductors and related model systems

  16. Flux-Vortex Pinning and Neutron Star Evolution

    Indian Academy of Sciences (India)

    Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately.

  17. A covalent PIN1 inhibitor selectively targets cancer cells by a dual mechanism of action

    Science.gov (United States)

    Campaner, Elena; Rustighi, Alessandra; Zannini, Alessandro; Cristiani, Alberto; Piazza, Silvano; Ciani, Yari; Kalid, Ori; Golan, Gali; Baloglu, Erkan; Shacham, Sharon; Valsasina, Barbara; Cucchi, Ulisse; Pippione, Agnese Chiara; Lolli, Marco Lucio; Giabbai, Barbara; Storici, Paola; Carloni, Paolo; Rossetti, Giulia; Benvenuti, Federica; Bello, Ezia; D'Incalci, Maurizio; Cappuzzello, Elisa; Rosato, Antonio; Del Sal, Giannino

    2017-06-01

    The prolyl isomerase PIN1, a critical modifier of multiple signalling pathways, is overexpressed in the majority of cancers and its activity strongly contributes to tumour initiation and progression. Inactivation of PIN1 function conversely curbs tumour growth and cancer stem cell expansion, restores chemosensitivity and blocks metastatic spread, thus providing the rationale for a therapeutic strategy based on PIN1 inhibition. Notwithstanding, potent PIN1 inhibitors are still missing from the arsenal of anti-cancer drugs. By a mechanism-based screening, we have identified a novel covalent PIN1 inhibitor, KPT-6566, able to selectively inhibit PIN1 and target it for degradation. We demonstrate that KPT-6566 covalently binds to the catalytic site of PIN1. This interaction results in the release of a quinone-mimicking drug that generates reactive oxygen species and DNA damage, inducing cell death specifically in cancer cells. Accordingly, KPT-6566 treatment impairs PIN1-dependent cancer phenotypes in vitro and growth of lung metastasis in vivo.

  18. Characterization of pinning stability of HTS Gd123 bulks by using a pulsed-field magnetization

    International Nuclear Information System (INIS)

    Taguchi, R; Miki, M; Tsuzuki, K; Izumi, M; Yamaguchi, K; Kimura, Y; Ida, T

    2010-01-01

    High-temperature superconductor (HTS) Gd-bulks are used for field-pole magnets of rotating machines. We have conducted a study of pulsed-field magnetization (PFM) for the bulks to be magnetized alternatively on the rotor. Performances of HTS bulks have been qualified on the basis of the field-cooling magnetization (FCM). HTS bulks are a kind of crystals containing lots of tiny crystals boundaries. It is difficult to find comparable data between PFM and FCM results, mainly because of the different pinning stability through both processes. We need to assess an effective method of characterization for the flux pinning stability under PFM. We compared two HTS bulks: one shows a flux flow and relatively small trapped flux while the other is magnetized with a little flux instability and a large integrated trapped flux. These Gd123 bulks are 100 mm in diameter and 20 mm in thickness. After applying PFM at the liquid nitrogen temperature, we measured the trapped field density distribution and introduced a new parameter representing the trapped flux instability at each position on the surface of the bulk. We propose a way of visualization of the flux pinning instability of the HTS bulks.

  19. The kinetics of root gravitropism in PIN mutants suggest redundancy in the signal transduction pathway

    Science.gov (United States)

    Wolverton, Chris

    As nonmotile organisms, plants rely on differential growth responses to maximize exposure to the resources necessary for growth and reproduction. One of the primary environmental cues causing differential growth in roots is gravity, which is thought to be sensed predominately in the root cap. This gravity perception event is thought to be transduced into information in the form of an auxin gradient across the cap and propagating basipetally toward the elongation zone. The discovery of several families of auxin efflux and influx carriers has provided significant insight into the mechanisms of directional auxin transport, and the identification of mutants in the genes encoding these carriers provides the opportunity to test the roles of these transporters in plant gravitropism. In this study, we report the results of a systematic, high-resolution study of the kinetics of root gravitropism of mutants in the PIN family of auxin efflux carriers. Based on reported expression and localization patterns, we predicted mutations in PIN2, PIN3, PIN4, and PIN7 to cause the greatest reduction in root gravitropism. While pin2 mutants showed severe gravitropic deficiencies in roots as reported previously, several alleles of pin3, pin4 and pin7 remained strongly gravitropic. PIN3 has been localized to the central columella cells, the purported gravisensing cells in the root, and shown to rapidly relocate to the lower flank of the columella cells upon gravistimulation, suggesting an early role in auxin gradient formation. Mutant alleles of PIN3 showed an early delay in response, with just 7 deg of curvature in the first hour compared to approximately 15 deg h-1 in wild-type, but their rate of curvature recovered to near wild-type levels over the ensuing 3 h. Pin3 mutants also showed a slower overall growth rate (124 µm h-1 ), elongating at approximately half the rate of wild-type roots (240 µm h-1 ). PIN4 has been localized to the quiescent center in the root, where it presumably

  20. Thermal-Hydraulic Simulations of Single Pin and Assembly Sector for IVG- 1M Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Garner, P. [Argonne National Lab. (ANL), Argonne, IL (United States); Hanan, N. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-01-15

    Thermal-hydraulic simulations have been performed using computational fluid dynamics (CFD) for the highly-enriched uranium (HEU) design of the IVG.1M reactor at the Institute of Atomic Energy (IAE) at the National Nuclear Center (NNC) in the Republic of Kazakhstan. Steady-state simulations were performed for both types of fuel assembly (FA), i.e. the FA in rows 1 & 2 and the FA in row 3, as well as for single pins in those FA (600 mm and 800 mm pins). Both single pin calculations and bundle sectors have been simulated for the most conservative operating conditions corresponding to the 10 MW output power, which corresponds to a pin unit cell Reynolds number of only about 7500. Simulations were performed using the commercial code STAR-CCM+ for the actual twisted pin geometry as well as a straight-pin approximation. Various Reynolds-Averaged Navier-Stokes (RANS) turbulence models gave different results, and so some validation runs with a higher-fidelity Large Eddy Simulation (LES) code were performed given the lack of experimental data. These singled out the Realizable Two-Layer k-ε as the most accurate turbulence model for estimating surface temperature. Single-pin results for the twisted case, based on the average flow rate per pin and peak pin power, were conservative for peak clad surface temperature compared to the bundle results. Also the straight-pin calculations were conservative as compared to the twisted pin simulations, as expected, but the single-pin straight case was not always conservative with regard to the straight-pin bundle. This was due to the straight-pin temperature distribution being strongly influenced by the pin orientation, particularly near the outer boundary. The straight-pin case also predicted the peak temperature to be in a different location than the twisted-pin case. This is a limitation of the straight-pin approach. The peak temperature pin was in a different location from the peak power pin in every case simulated, and occurred at an

  1. PIN6 auxin transporter at endoplasmic reticulum and plasma membrane mediates auxin homeostasis and organogenesis in Arabidopsis.

    Science.gov (United States)

    Simon, Sibu; Skůpa, Petr; Viaene, Tom; Zwiewka, Marta; Tejos, Ricardo; Klíma, Petr; Čarná, Mária; Rolčík, Jakub; De Rycke, Riet; Moreno, Ignacio; Dobrev, Petre I; Orellana, Ariel; Zažímalová, Eva; Friml, Jiří

    2016-07-01

    Plant development mediated by the phytohormone auxin depends on tightly controlled cellular auxin levels at its target tissue that are largely established by intercellular and intracellular auxin transport mediated by PIN auxin transporters. Among the eight members of the Arabidopsis PIN family, PIN6 is the least characterized candidate. In this study we generated functional, fluorescent protein-tagged PIN6 proteins and performed comprehensive analysis of their subcellular localization and also performed a detailed functional characterization of PIN6 and its developmental roles. The localization study of PIN6 revealed a dual localization at the plasma membrane (PM) and endoplasmic reticulum (ER). Transport and metabolic profiling assays in cultured cells and Arabidopsis strongly suggest that PIN6 mediates both auxin transport across the PM and intracellular auxin homeostasis, including the regulation of free auxin and auxin conjugates levels. As evidenced by the loss- and gain-of-function analysis, the complex function of PIN6 in auxin transport and homeostasis is required for auxin distribution during lateral and adventitious root organogenesis and for progression of these developmental processes. These results illustrate a unique position of PIN6 within the family of PIN auxin transporters and further add complexity to the developmentally crucial process of auxin transport. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  2. Unicortical self-drilling external fixator pins reduce thermal effects during pin insertion.

    Science.gov (United States)

    Greinwald, Markus; Varady, Patrick A; Augat, Peter

    2017-12-14

    External fixation is associated with the risk of pin loosening and pin infection potentially associated to thermal bone necrosis during pin insertion. This study aims to investigate if the use of external fixator systems with unicortical pins reduces the heat production during pin insertion compared to fixators with bicortical pins. Porcine bone specimens were employed to determine bone temperatures during insertion of fixator pins. Two thermographic cameras were used for a simultaneous temperature measurement on the bone surface (top view) and a bone cross-section (front view). Self-drilling unicortical and bicortical pins were inserted at different rotational speeds: (30-600) rpm. Maximum and mean temperatures of the emerging bone debris, bone surface and bone cross-section were analyzed. Maximum temperatures of up to 77 ± 26 °C were measured during pin insertion in the emerging debris and up to 42 ± 2 °C on the bone surface. Temperatures of the emerging debris increased with increasing rotational speeds. Bicortical pin insertion generated significantly higher temperatures at low insertion speed (30 rpm) CONCLUSION: The insertion of external fixator pins can generate a considerable amount of heat around the pins, primarily emerging from bone debris and at higher insertion speeds. Our findings suggest that unicortical, self-drilling fixator pins have a decreased risk for thermal damage, both to the surrounding tissue and to the bone itself.

  3. Spectroscopic amplifier for pin diode; Amplificador espectroscopico para diodo Pin

    Energy Technology Data Exchange (ETDEWEB)

    Alonso M, M. S.; Hernandez D, V. M.; Vega C, H. R., E-mail: bebe.luna_s@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2014-10-15

    The photodiode remains the basic choice for the photo-detection and is widely used in optical communications, medical diagnostics and field of corpuscular radiation. In detecting radiation it has been used for monitoring radon and its progeny and inexpensive spectrometric systems. The development of a spectroscopic amplifier for Pin diode is presented which has the following characteristics: canceler Pole-Zero (P/Z) with a time constant of 8 μs; constant gain of 57, suitable for the acquisition system; 4th integrator Gaussian order to waveform change of exponential input to semi-Gaussian output and finally a stage of baseline restorer which prevents Dc signal contribution to the next stage. The operational amplifier used is the TLE2074 of BiFET technology of Texas Instruments with 10 MHz bandwidth, 25 V/μs of slew rate and a noise floor of 17 nv/(Hz)1/2. The integrated circuit has 4 operational amplifiers and in is contained the total of spectroscopic amplifier that is the goal of electronic design. The results show like the exponential input signal is converted to semi-Gaussian, modifying only the amplitude according to the specifications in the design. The total system is formed by the detector, which is the Pin diode, a sensitive preamplifier to the load, the spectroscopic amplifier that is what is presented and finally a pulse height analyzer (Mca) which is where the spectrum is shown. (Author)

  4. Pin Wire Coating Trip Report

    International Nuclear Information System (INIS)

    Spellman, G P

    2004-01-01

    A meeting to discuss the current pin wire coating problems was held at the Reynolds plant in Los Angeles on 2MAR04. The attendance list for Reynolds personnel is attached. there was an initial presentation which gave a brief history and the current status of pin wire coating at Reynolds. There was a presentation by Lori Primus on the requirements and issues for the coating. There was a presentation by Jim Smith of LANL on the chemistry and to some extent process development done to date. There was a long session covering what steps should be taken in the short term and, to a lesser extent, the long term. The coating currently being used is a blend of two polymers, polyethersulfone and polyparabanic acid (PPA) and some TiO2 filler. This system was accepted and put into production when the pin wire coating was outsourced to another company in 1974. When that company no longer was interested, the wire coating was brought in-house to Reynolds. At that time polyparabanic acid was actually a commercial product available from Exxon under the trade name Tradlon. However, it appears that the material used at Reynolds was synthesized locally. Also, it appears that a single large batch was synthesized in that time period and used up to 1997 when the supply ran out. The reason for the inclusion of TiO2 is not known although it does act as a rheological thickener. However, a more controlled thickening can be obtained with materials such as fumed silica. This material would have less likelihood of causing point imperfections in the coatings. Also, the mixing technique being used for all stages of the process is a relatively low shear ball mill process and the author recommends a high shear process such as a three roll paint mill, at least for the final mixing. Since solvent is added to the powder at Reynolds, it may be that they need to have the paint mill there

  5. Auxin efflux by PIN-FORMED proteins is activated by two different protein kinases, D6 PROTEIN KINASE and PINOID

    KAUST Repository

    Zourelidou, Melina

    2014-06-19

    The development and morphology of vascular plants is critically determined by synthesis and proper distribution of the phytohormone auxin. The directed cell-to-cell distribution of auxin is achieved through a system of auxin influx and efflux transporters. PIN-FORMED (PIN) proteins are proposed auxin efflux transporters, and auxin fluxes can seemingly be predicted based on the-in many cells-asymmetric plasma membrane distribution of PINs. Here, we show in a heterologous Xenopus oocyte system as well as in Arabidopsis thaliana inflorescence stems that PIN-mediated auxin transport is directly activated by D6 PROTEIN KINASE (D6PK) and PINOID (PID)/WAG kinases of the Arabidopsis AGCVIII kinase family. At the same time, we reveal that D6PKs and PID have differential phosphosite preferences. Our study suggests that PIN activation by protein kinases is a crucial component of auxin transport control that must be taken into account to understand auxin distribution within the plant.

  6. Vortex pinning in superconducting Nb thin films deposited on nanoporous alumina templates

    DEFF Research Database (Denmark)

    Vinckx, W.; Vanacken, J.; Moshchalkov, V.V.

    2006-01-01

    We present a study of magnetization and transport properties of superconducting Nb thin films deposited on nanoporous aluminium oxide templates. Periodic oscillations in the critical temperature vs. field, matching effects in fields up to 700 mT and strongly enhanced critical currents were observed....... These fields are considerably higher than those typical for periodic pinning arrays made by lithographic techniques, which reflects the benefits of nanostructuring superconductors by using self-organized growth. This method provides a periodic pinning potential with sub-100 nm spacing between the pinning...

  7. Vortex phase diagram studies in the weakly pinned single crystals of ...

    Indian Academy of Sciences (India)

    flux line lattice symmetry have been reported in these systems via the small angle neutron scattering experiments. .... parable to the penetration depth value in the YNi2B2C system [20,36]. However, it is known that ..... 6 attest to the scaling behaviour operative for the pinning force as regards the PE phenomenon, and this is ...

  8. Heat Exchanger With Internal Pin Elements

    Science.gov (United States)

    Gerstmann, Joseph; Hannon, Charles L.

    2004-01-13

    A heat exchanger/heater comprising a tubular member having a fluid inlet end, a fluid outlet end and plurality of pins secured to the interior wall of the tube. Various embodiments additionally comprise a blocking member disposed concentrically inside the pins, such as a core plug or a baffle array. Also disclosed is a vapor generator employing an internally pinned tube, and a fluid-heater/heat-exchanger utilizing an outer jacket tube and fluid-side baffle elements, as well as methods for heating a fluid using an internally pinned tube.

  9. Integral Fast Reactor fuel pin processor

    International Nuclear Information System (INIS)

    Levinskas, D.

    1993-01-01

    This report discusses the pin processor which receives metal alloy pins cast from recycled Integral Fast Reactor (IFR) fuel and prepares them for assembly into new IFR fuel elements. Either full length as-cast or precut pins are fed to the machine from a magazine, cut if necessary, and measured for length, weight, diameter and deviation from straightness. Accepted pins are loaded into cladding jackets located in a magazine, while rejects and cutting scraps are separated into trays. The magazines, trays, and the individual modules that perform the different machine functions are assembled and removed using remote manipulators and master-slaves

  10. Spectroscopic amplifier for pin diode

    International Nuclear Information System (INIS)

    Alonso M, M. S.; Hernandez D, V. M.; Vega C, H. R.

    2014-10-01

    The photodiode remains the basic choice for the photo-detection and is widely used in optical communications, medical diagnostics and field of corpuscular radiation. In detecting radiation it has been used for monitoring radon and its progeny and inexpensive spectrometric systems. The development of a spectroscopic amplifier for Pin diode is presented which has the following characteristics: canceler Pole-Zero (P/Z) with a time constant of 8 μs; constant gain of 57, suitable for the acquisition system; 4th integrator Gaussian order to waveform change of exponential input to semi-Gaussian output and finally a stage of baseline restorer which prevents Dc signal contribution to the next stage. The operational amplifier used is the TLE2074 of BiFET technology of Texas Instruments with 10 MHz bandwidth, 25 V/μs of slew rate and a noise floor of 17 nv/(Hz)1/2. The integrated circuit has 4 operational amplifiers and in is contained the total of spectroscopic amplifier that is the goal of electronic design. The results show like the exponential input signal is converted to semi-Gaussian, modifying only the amplitude according to the specifications in the design. The total system is formed by the detector, which is the Pin diode, a sensitive preamplifier to the load, the spectroscopic amplifier that is what is presented and finally a pulse height analyzer (Mca) which is where the spectrum is shown. (Author)

  11. The two-dimensional vibrating reed technique. A study of anisotropic pinning in high-temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Karelina, Anna

    2004-02-18

    In this work the anisotropy of the pinning forces of vortices in a-b plane of high temperature-supraconductors was examined. For this purpose vibrating reed with two degrees of freedom of the oscillation was constructed. The pinning forces were examined in single crystals of YBa{sub 2}Cu{sub 3}O{sub 7} and Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}. The experiments with YBa{sub 2}Cu{sub 3}O{sub 7} show that at temperatures lower than 78 K the vortices are in a nonequilibrium state. This leads to a flux creep and to a drift of the resonance frequency with time. This prevents the comparison of resonance curves in different directions of oscillations. In Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} single crystals the vortices are in more stable state, but the measurements of the resonance curves in different directions show no indication of the four-fold symmetry. At temperatures below 60 K a strong hysteresis of the resonance frequency and the resonance-oscillation amplitude was found in YBa{sub 2}Cu{sub 3}O{sub 7} crystals as a function of the magnetic field. (orig.)

  12. Performance of IN-706 and PE-16 cladding in mixed-oxide fuel pins

    International Nuclear Information System (INIS)

    Makenas, B.J.; Lawrence, L.A.; Jensen, B.W.

    1982-05-01

    Iron-nickel base, precipitation-strengthened alloys, IN-706 and PE-16, advanced alloy cladding considered for breeder reactor applications, were irradiated in mixed-oxide fuel pins in the HEDL-P-60 subassembly in EBR-II. Initial selection of candidate advanced alloys was done using only nonfueled materials test results. However, to establish the performance characteristics of the candidate cladding alloys, i.e., dimensional stability and structural integrity under conditions of high neutron flux, elevated temperature, and applied stress, it was necessary to irradiate fuel pins under typical operating conditions. Fuel pins were clad with solution treated IN-706 and PE-16 and irradiated to peak fluences of 6.1 x 10 22 n/cm 2 (E > .1 MeV) and 8.8 x 10 22 n/cm 2 (E > .1 MeV) respectively. Fabrication and operating parameters for the fuel pins with the advanced cladding alloy candidates are summarized. Irradiation of HEDL-P-60 was interrupted with the breach of a pin with IN-706 cladding at 5.1 at % and the test was terminated with cladding breach in a pin with PE-16 cladding at 7.6 at %

  13. A comparative CFD investigation of helical wire-wrapped 7, 19 and 37 fuel pin bundles and its extendibility to 217 pin bundle

    International Nuclear Information System (INIS)

    Gajapathy, R.; Velusamy, K.; Selvaraj, P.; Chellapandi, P.; Chetal, S.C.

    2009-01-01

    Preliminary investigations of sodium flow and temperature distributions in heat generating fuel pin bundles with helical spacer wires have been carried out. Towards this, the 3D conservation equations of mass, momentum and energy have been solved using a commercial computational fluid dynamics (CFD) code. Turbulence has been accounted through the use of high Reynolds number version of standard k-ε model, with uniform mesh density respecting wall function requirements. The geometric details of the bundle and the heat flux in are similar to that of the Indian Prototype Fast Breeder Reactor (PFBR) that is currently under construction. The mixing characteristics of the flow among the peripheral and central zones are compared for 7, 19 and 37 fuel pin bundles and the characteristics are extended to a 217 pin bundle. The friction factors of the pin bundles obtained from the present study is seen to agree well with the values derived from experimental correlations. It is found that the normalized outlet velocities in the peripheral and central zones are nearly equal to 1.1-0.9, respectively which is in good agreement with the published hydraulic experimental measurements of 1.1-0.85 for a 91 pin bundle. The axial velocity is the maximum in the peripheral zone where spacer wires are located and minimum in the zones which are diametrically opposite to the respective zone of maximum velocity. The sodium temperature is higher in the zones where the flow area and mass flow rates are less due to the presence of the spacer wires though the axial velocity is higher there. It is the minimum in the peripheral zones where the circumferential flow is larger. Based on the flow and temperature distributions obtained for 19 and 37 pin bundles, a preliminary extrapolation procedure has been established for estimating the temperatures of peripheral and central zones of 217 pin bundle.

  14. Failure Analysis of Electrical Pin Connectors

    Science.gov (United States)

    Newman, John A.; Baughman, James M.; Smith, Stephen W.; Herath, Jeffrey A.

    2008-01-01

    A study was initiated to determine the root cause of failure for circuit board electrical connection pins that failed during vibRatory testing. The circuit board is part of an unmanned space probe, and the vibratory testing was performed to ensure component survival of launch loading conditions. The results of this study show that the pins failed as a result of fatigue loading.

  15. Jig Quickly Checks Connector Pin Alinement

    Science.gov (United States)

    Hall, W. M.; Papac, T. P.

    1983-01-01

    Test jig checks whether pins of connector are within location tolerance. Jig greatly reduces test time. Machined slots on opposite faces of plate form matrix of rectangular windows at intersections. If connector pin is out of alinement, it makes electrical contact with side of window, triggering indicator.

  16. TACO: fuel pin performance analysis

    International Nuclear Information System (INIS)

    Stoudt, R.H.; Buchanan, D.T.; Buescher, B.J.; Losh, L.L.; Wilson, H.W.; Henningson, P.J.

    1977-08-01

    The thermal performance of fuel in an LWR during its operational lifetime must be described for LOCA analysis as well as for other safety analyses. The determination of stored energy in the LOCA analysis, for example, requires a conservative fuel pin thermal performance model that is capable of calculating fuel and cladding behavior, including the gap conductance between the fuel and cladding, as a function of burnup. The determination of parameters that affect the fuel and cladding performance, such as fuel densification, fission gas release, cladding dimensional changes, fuel relocation, and thermal expansion, should be accounted for in the model. Babcock and Wilcox (B and W) has submitted a topical report, BAW-10087P, December 1975, which describes their thermal performance model TACO. A summary of the elements that comprise the TACO model and an evaluation are presented

  17. Analysis of PWR control rod ejection accident with the coupled code system SKETCH-INS/TRACE by incorporating pin power reconstruction model

    International Nuclear Information System (INIS)

    Nakajima, T.; Sakai, T.

    2010-01-01

    The pin power reconstruction model was incorporated in the 3-D nodal kinetics code SKETCH-INS in order to produce accurate calculation of three-dimensional pin power distributions throughout the reactor core. In order to verify the employed pin power reconstruction model, the PWR MOX/UO 2 core transient benchmark problem was analyzed with the coupled code system SKETCH-INS/TRACE by incorporating the model and the influence of pin power reconstruction model was studied. SKETCH-INS pin power distributions for 3 benchmark problems were compared with the PARCS solutions which were provided by the host organisation of the benchmark. SKETCH-INS results were in good agreement with the PARCS results. The capability of employed pin power reconstruction model was confirmed through the analysis of benchmark problems. A PWR control rod ejection benchmark problem was analyzed with the coupled code system SKETCH-INS/ TRACE by incorporating the pin power reconstruction model. The influence of pin power reconstruction model was studied by comparing with the result of conventional node averaged flux model. The results indicate that the pin power reconstruction model has significant effect on the pin powers during transient and hence on the fuel enthalpy

  18. Pin fin compliant heat sink with enhanced flexibility

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, Mark D.

    2018-04-10

    Heat sinks and methods of using the same include a top and bottom plate, at least one of which has a plurality of pin contacts flexibly connected to one another, where the plurality of pin contacts have vertical and lateral flexibility with respect to one another; and pin slice layers, each having multiple pin slices, arranged vertically between the top and bottom plates such that the plurality of pin slices form substantially vertical pins connecting the top and bottom plates.

  19. Effects of Auxins on PIN-FORMED2 (PIN2) Dynamics Are Not Mediated by Inhibiting PIN2 Endocytosis1

    Science.gov (United States)

    Jásik, Ján; Bokor, Boris; Stuchlík, Stanislav; Mičieta, Karol; Turňa, Ján; Schmelzer, Elmon

    2016-01-01

    By using the photoconvertible fluorescence protein Dendra2 as a tag we demonstrated that neither the naturally occurring auxins indole-3-acetic acid and indole-3-butyric acid, nor the synthetic auxin analogs 1-naphthaleneacetic acid and 2,4-dichlorophenoxyacetic acid nor compounds inhibiting polar auxin transport such as 2,3,5-triiodobenzoic acid and 1-N-naphthylphthalamic acid, were able to inhibit endocytosis of the putative auxin transporter PIN-FORMED2 (PIN2) in Arabidopsis (Arabidopsis thaliana) root epidermis cells. All compounds, except Indole-3-butyric acid, repressed the recovery of the PIN2-Dendra2 plasma membrane pool after photoconversion when they were used in high concentrations. The synthetic auxin analogs 1-naphthaleneacetic acid and 2,4-dichlorophenoxyacetic acid showed the strongest inhibition. Auxins and auxin transport inhibitors suppressed also the accumulation of both newly synthesized and endocytotic PIN2 pools in Brefeldin A compartments (BFACs). Furthermore, we demonstrated that all compounds are also interfering with BFAC formation. The synthetic auxin analogs caused the highest reduction in the number and size of BFACs. We concluded that auxins and inhibitors of auxin transport do affect PIN2 turnover in the cells, but it is through the synthetic rather than the endocytotic pathway. The study also confirmed inappropriateness of the BFA-based approach to study PIN2 endocytosis because the majority of PIN2 accumulating in BFACs is newly synthesized and not derived from the plasma membrane. PMID:27506239

  20. Effects of Auxins on PIN-FORMED2 (PIN2) Dynamics Are Not Mediated by Inhibiting PIN2 Endocytosis.

    Science.gov (United States)

    Jásik, Ján; Bokor, Boris; Stuchlík, Stanislav; Mičieta, Karol; Turňa, Ján; Schmelzer, Elmon

    2016-10-01

    By using the photoconvertible fluorescence protein Dendra2 as a tag we demonstrated that neither the naturally occurring auxins indole-3-acetic acid and indole-3-butyric acid, nor the synthetic auxin analogs 1-naphthaleneacetic acid and 2,4-dichlorophenoxyacetic acid nor compounds inhibiting polar auxin transport such as 2,3,5-triiodobenzoic acid and 1-N-naphthylphthalamic acid, were able to inhibit endocytosis of the putative auxin transporter PIN-FORMED2 (PIN2) in Arabidopsis (Arabidopsis thaliana) root epidermis cells. All compounds, except Indole-3-butyric acid, repressed the recovery of the PIN2-Dendra2 plasma membrane pool after photoconversion when they were used in high concentrations. The synthetic auxin analogs 1-naphthaleneacetic acid and 2,4-dichlorophenoxyacetic acid showed the strongest inhibition. Auxins and auxin transport inhibitors suppressed also the accumulation of both newly synthesized and endocytotic PIN2 pools in Brefeldin A compartments (BFACs). Furthermore, we demonstrated that all compounds are also interfering with BFAC formation. The synthetic auxin analogs caused the highest reduction in the number and size of BFACs. We concluded that auxins and inhibitors of auxin transport do affect PIN2 turnover in the cells, but it is through the synthetic rather than the endocytotic pathway. The study also confirmed inappropriateness of the BFA-based approach to study PIN2 endocytosis because the majority of PIN2 accumulating in BFACs is newly synthesized and not derived from the plasma membrane. © 2016 American Society of Plant Biologists. All Rights Reserved.

  1. Fracture repair with transfixation pins and fiberglass cast in llamas and small ruminants.

    Science.gov (United States)

    Kaneps, A J; Schmotzer, W B; Huber, M J; Riebold, T W; Watrous, B J; Arnold, J S

    1989-11-01

    Transfixation pinning with fiberglass casting is an effective and adaptable method of longbone fracture fixation in llamas and small ruminants. Treatment of fractures in 7 limbs of 4 llamas and 2 small ruminants with this technique are described. Steinmann pins are placed transcortically proximal, and if necessary, distal to the fracture. The pin ends and limb are encased in fiberglass cast material. The cast is strong enough in animals of this size to eliminate the need for external frames or connecting bars. Severely comminuted fractures and fractures near joints are especially suited to fixation with this technique. Complications encountered in these cases included loosening of pins and one delayed union. All fractures healed to permit full use of the limb.

  2. Strongly enhanced irreversibility fields and Bose-glass behaviour in bulk YBCO with discontinuous columnar irradiation defects

    International Nuclear Information System (INIS)

    Fuchs, G; Nenkov, K; Krabbes, G; Weinstein, R; Gandini, A; Sawh, R; Mayes, B; Parks, D

    2007-01-01

    Flux pinning properties and irreversibility fields B irr (T) of melt-textured YBCO with discontinuous or multiple-in-line-damage (MILD) columnar defects produced by irradiation with high-energy U 238 ions were studied at a constant matching field of B φ = 10 T and for several energy losses between S e = 1.67 and 2.4 keV A -1 . With increasing S e and increasing length of the MILD pins, the critical current density j c (H,T) strongly increases and B irr (T) for fields along the c axis progressively shifts upwards reaching 9 T at 77 K. For S e = 2.4 keV A -1 , a pronounced kink is observed in B irr (T) at 8 T which is a strong indication of Bose-glass behaviour. The j c (H) dependence of this sample shows a peak at a low applied field B p . This peak effect is explained by the entanglement of vortices. It is argued that for MILD pins single vortices interact simultaneously with many short columnar defects in neighbouring ion trails resulting in an automatic splay in the vortex orientation. The observed decrease of B p with increasing temperature is estimated taking the increasing thermal fluctuations into account

  3. Stresses in pin-loaded tubes

    Science.gov (United States)

    Ahmad, Ishtiaq

    This thesis deals with a parametric 3-dimensional photoelastic study of the stresses in pin-loaded tubes, commonly used in securing an aircraft engine into the air frame. Among the geometric variables studied (normalised with reference to the outer tube diameter) are included form values of the ratio of pin-hole diameter to outer tube diameter (0.10, 0.20, 0.40 and 0.60), four different hole-centre positions relative to the tube end and six values of the ratio of tube thickness to outer tube diameter (0.04, 0.08, 0.16, 0.25, 0.32 and 0.50). The other variables investigated are clearance between pin and hole, pin stiffness and lubrication. Some combinations of pairs of pins, either parallel or "crossed" have also been studied, and the effects of different modes of tensile loading, compressive loading, bending loading and torsional loading have been assessed. The results include details of the distribution of normalised changes in tube diameter along the planes of symmetry, the distribution of stress indices around the tube ends, the distribution of stress indices along planes of symmetry and the distribution of stress indices around the pin-loaded holes. The work is discussed in detail. The results provide a valuable reference in the design of pin-loaded tubes.

  4. Cesium chemistry in GCFR fuel pins

    International Nuclear Information System (INIS)

    Fee, D.C.; Johnson, C.E.

    1979-01-01

    The fuel rod design for the Gas Cooled Fast-Breeder Reactor (GCFR) is similar to that employed for the Liquid Metal Fast Breeder Reactor (LMFBR) with the exception of the unique features inherent to the use of helium as the coolant. These unique design features include the use of (1) vented and pressure-equalized fuel rods, and (2) ribbed cladding along 75% of the fuel section. The former design feature enables reduction in cladding thickness and prevention of possible creep collapse of the cladding due to the high coolant pressure (8.5 MPa). The latter design feature brings about improved heat transfer characteristics. Each GCFR fuel rod is vented to a manifold whereby gaseous fission products diffusing out of the fuel pin are retained on charcoal traps. As a result, the internal pressure of a GCFR fuel pin does not increase during irradiation. In addition, the venting system also maintains the pressure within the fuel pin slightly below (0.3 to 0.5 MPa) the coolant pressure outside the fuel pin. Consequently, should a breach occur in the cladding, helium flows into the breached fuel pin thereby minimizing fission product contamination of the coolant. These desirable aspects of a GCFR fuel pin can be maintained only as long as axial gas transport paths are available and operating within the fuel pin

  5. Thickness-modulated tungsten-carbon superconducting nanostructures grown by focused ion beam induced deposition for vortex pinning up to high magnetic fields.

    Science.gov (United States)

    Serrano, Ismael García; Sesé, Javier; Guillamón, Isabel; Suderow, Hermann; Vieira, Sebastián; Ibarra, Manuel Ricardo; De Teresa, José María

    2016-01-01

    We report efficient vortex pinning in thickness-modulated tungsten-carbon-based (W-C) nanostructures grown by focused ion beam induced deposition (FIBID). By using FIBID, W-C superconducting films have been created with thickness modulation properties exhibiting periodicity from 60 to 140 nm, leading to a strong pinning potential for the vortex lattice. This produces local minima in the resistivity up to high magnetic fields (2.2 T) in a broad temperature range due to commensurability effects between the pinning potential and the vortex lattice. The results show that the combination of single-step FIBID fabrication of superconducting nanostructures with built-in artificial pinning landscapes and the small intrinsic random pinning potential of this material produces strong periodic pinning potentials, maximizing the opportunities for the investigation of fundamental aspects in vortex science under changing external stimuli (e.g., temperature, magnetic field, electrical current).

  6. COMETHE III J a computer code for predicting mechanical and thermal behaviour of a fuel pin

    International Nuclear Information System (INIS)

    Verbeek, P.; Hoppe, N.

    1976-01-01

    The design of fuel pins for power reactors requires a realistic evaluation of their thermal and mechanical performances throughout their irradiation life. This evaluation involves the knowledge of a number of parameters, very intricate and interconnected, for example, the temperature, the restructuring and the swelling rates of the fuel pellets, the dimensions, the stresses and the strains in the clad, the composition and the properties of gases, the inner gas pressure etc. This complex problem can only be properly handled by a computer programme which analyses the fuel pin thermal and mechanical behaviour at successive steps of its irradiation life. This report presents an overall description of the COMETHE III-J computer programme, designed to calculate the integral performance of oxide fuel pins with cylindrical metallic cladding irradiated in thermal or fast flux. (author)

  7. Equalized radiography using special modulator pins

    Energy Technology Data Exchange (ETDEWEB)

    Aitkenhead, W.F.; Gershman, R.J.

    1991-11-19

    This patent describes a system for examining an object with penetrating radiation. It comprises a source/modulator which generates a fan of penetrating radiation scanning an object position and comprises wedge- shaped pins of a radiation attenuating material movable into the fan in the scanning direction and arranged in at least one row extending in a direction transverse to both the scanning direction and the propagation direction of the radiation; each of the pins having a ridge pointing to or away from the origin of the fan and each pin having sections of different areas in different planes normal to the scanning direction; and a control circuit moving the pins individually to respective degrees into the scanning fan.

  8. Pinning Synchronization of Switched Complex Dynamical Networks

    Directory of Open Access Journals (Sweden)

    Liming Du

    2015-01-01

    Full Text Available Network topology and node dynamics play a key role in forming synchronization of complex networks. Unfortunately there is no effective synchronization criterion for pinning synchronization of complex dynamical networks with switching topology. In this paper, pinning synchronization of complex dynamical networks with switching topology is studied. Two basic problems are considered: one is pinning synchronization of switched complex networks under arbitrary switching; the other is pinning synchronization of switched complex networks by design of switching when synchronization cannot achieved by using any individual connection topology alone. For the two problems, common Lyapunov function method and single Lyapunov function method are used respectively, some global synchronization criteria are proposed and the designed switching law is given. Finally, simulation results verify the validity of the results.

  9. Ultrasonic inspections of fuel alignment pins

    International Nuclear Information System (INIS)

    Rathgeb, W.; Schmid, R.

    1994-01-01

    As a remedy to the practical problem of defects in fuel alignment pins made of Inconel X750, an inspection technique has been developed which fully meets the requirements of detecting defects. The newly used fuel alignment pins made of austenite are easy to test and therefore satisfy the necessity of further inspections.For the fuel alignment pins of the upper core structure a safe and fast inspection technique was made available. The inspection sensitivity is high and it is possible to give quantitative directions concerning defect orientation and depth. After the required inspections had been concluded in 1989, a total of 18 inspections were carried out in various national and international nuclear power plants in the following years. During this time more than 6000 fuel alignment pines were examined.For the fuel alignment pins the inspection technique provided could increase the understanding of the defect process. This technique contributed to the development of an adaptive and economical repair strategy. ((orig.))

  10. LOFT DTT rake pin stress analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mosby, W.R.

    1979-01-23

    A stress analysis of the 3/8-inch and 1/4-inch pins which hold the rake assembly to the flange was performed and shows stresses to be lower than the Class 1 allowables of the ASME Boiler and Pressure Vessel Code. The alternating pin stresses were found to be below the endurance limit and fatigue failure will not occur. The rake assembly was assumed to be loaded by steady drag and lift forces and alternating vortex shedding forces.

  11. IMp: The customizable LEGO® Pinned Insect Manipulator

    Directory of Open Access Journals (Sweden)

    Steen Dupont

    2015-02-01

    Full Text Available We present a pinned insect manipulator (IMp constructed of LEGO® building bricks with two axes of movement and two axes of rotation. In addition we present three variants of the IMp to emphasise the modular design, which facilitates resizing to meet the full range of pinned insect specimens, is fully customizable, collapsible, affordable and does not require specialist tools or knowledge to assemble.

  12. Fabrication drawings of fuel pins for FUJI project among PSI, JNC and NRG. Revised version

    International Nuclear Information System (INIS)

    Ozawa, Takayuki; Nakazawa, Hiroaki; Abe, Tomoyuki; Nagayama, Masahiro

    2002-02-01

    Irradiation tests and post-irradiation examinations in the framework of JNC-PSI-NRG collaboration project will be performed in 2003-2005. Irradiation fuel pins will be fabricated by the middle of 2003. The fabrication procedure for irradiation fuel pins has been started in 2001. Several fabrication tests and qualification tests in JNC and PSI (Paul Scherrer Institute, Switzerland) have been performed before the fuel pin fabrication. According to the design assignment between PSI and JNC in the frame of this project, PSI should make a specification document for the fuel pellet, the sphere-pac fuel particles, the vipac fuel particles, and the fuel pin. JNC should make a fabrication drawing for irradiation pins. JNC has been performed the fuel design in cooperation with PSI and NRG (Nuclear Research and Consultancy Group, Netherlands). In this project, the pelletized fuel, the sphere-pac fuel, and the vipac fuel will be simultaneously irradiated on HFR (High Flux Reactor, Netherlands). This fabrication drawing has been made under the design assignment with PSI, and consists of the drawing of MOX pellet, thermal insulator pellet, pin components, fuel segments, and the constructed pin. The fabrication drawings were approved in October 2001, but after that, the optimization of specifications has been discussed and agreed among all partners. In this report, the revised fabrication drawings will be shown. Based on the commission of Plutonium Fuel Technology Group, Advanced Fuel Recycle Technology Division, this design work has been performed in Fuel Design and Evaluation Group, Plutonium Fuel Fabrication Division, Plutonium Fuel Center. (author)

  13. Tailoring the vortex pinning strength of YBCO thin films by systematic incorporation of hybrid artificial pinning centers

    Science.gov (United States)

    Jha, Alok K.; Matsumoto, Kaname; Horide, Tomoya; Saini, Shrikant; Mele, Paolo; Ichinose, Ataru; Yoshida, Yutaka; Awaji, Satoshi

    2015-11-01

    The effect of hybrid (columnar and spherical together) artificial pinning centers (APCs) on the vortex pinning properties of YBa2Cu3O7-δ (YBCO) thin films is investigated in detail on the basis of variation of critical current density (J C ) with applied magnetic field and also with the orientation of the applied magnetic field at 65 K and 77 K. Premixed YBCO + BaSnO3 composite targets are used for the deposition of the YBCO films which consist of self-assembled BaSnO3 nanocolumns (1D APCs); on the other hand, for the deposition of the YBCO films with hybrid APCs (BaSnO3 nanocolumns together with Y2O3 nanoparticles), the surface of the premixed YBCO + BaSnO3 composite targets are modified by putting a thin Y2O3 sectored piece on the premixed YBCO + BaSnO3 composite targets by means of silver paste. F pmax value increases systematically with incorporation of 1D and 1D and 3D APCs and it also shifts towards higher applied magnetic fields. Films with 1D APCs exhibit a strong J C peak at Θ = 0° (H//c-axis) whereas films consisting of hybrid APCs exhibit enhanced J C at all the investigated angular regimes. A possible mechanism of vortex pinning in samples with hybrid APCs is also discussed suggesting the role of 1D and 3D APCs.

  14. Improved pinning by multiple in-line damage

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Roy [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Sawh, Ravi-Persad [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Gandini, Alberto [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Parks, Drew [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States)

    2005-02-01

    Columnar pinning centres provide the largest pinning potential, U{sub pin}, but not the greatest J{sub c} or pinnable field, B{sub pin}. Characteristics of ion-generated columnar defects which limit J{sub c} and B{sub pin} are discussed, including reduction of the percolation path, and the need for a larger number of columns of damage, for pinning, than are usually estimated. It is concluded that columnar pinning centres limit B{sub pin} to less than 4 T, and also severely reduce J{sub c}. The goal of maximizing U{sub pin}, via columnar centres, appears to have obscured a more rewarding approach and resulted in neglect of a large regime of ion interactions. Evidence is reviewed that multiple in-line damage (MILD), described herein, can provide orders of magnitude higher J{sub c} and B{sub pin}, despite providing lower U{sub pin}. The MILD pinning centre morphology is discussed, and it is estimated that for present-day large grain high T{sub c} superconductors, a J{sub c} value of {approx}10{sup 6}Acm{sup -2} is obtainable at 77 K, even when crystal plane alignment and weak links are not improved. In addition, the pinned field is increased by over an order of magnitude. An experiment is proposed to confirm these calculations, directly compare MILD pinning to continuous columnar pinning, and determine the optimum MILD structure. Applications of MILD pinning are discussed.

  15. Glassy dynamics in randomly pinned particle systems

    Science.gov (United States)

    Phan, Anh; Schweizer, Kenneth

    We generalize the force-level, microscopic Elastically Collective Nonlinear Langevin Equation theory of activated relaxation in bulk hard sphere and thermal liquids to address the role of internal quenched disorder. So-called neutral confinement is considered where a subset of particles are randomly pinned and there is no change of equilibrium pair structure. As the pinned fraction grows, the cage scale dynamical constraints are intensified, resulting in the mobile particles becoming more localized, a larger glassy shear modulus, and an enhanced cage scale barrier. However, based on an approximate analysis of how quenched disorder modifies collective elastic field fluctuations, random pinning is predicted to effectively screen or localize the strain field associated with the longer range elastic component of the activation barrier, leading to an overall reduction of it with pinning fraction. The different response of the cage and elastic barriers to quenched disorder results in subtle predictions for how the alpha relaxation time varies with pinning fraction and system volume fraction. A semi-quantitative comparison with recent simulations of a pinned-mobile water model are consistent with the theory. Predictions are made for thermal molecular liquids.

  16. Fermi Level Pinning at Electrical Metal Contacts of Monolayer Molybdenum Dichalcogenides.

    Science.gov (United States)

    Kim, Changsik; Moon, Inyong; Lee, Daeyeong; Choi, Min Sup; Ahmed, Faisal; Nam, Seunggeol; Cho, Yeonchoo; Shin, Hyeon-Jin; Park, Seongjun; Yoo, Won Jong

    2017-02-28

    Electrical metal contacts to two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDCs) are found to be the key bottleneck to the realization of high device performance due to strong Fermi level pinning and high contact resistances (R c ). Until now, Fermi level pinning of monolayer TMDCs has been reported only theoretically, although that of bulk TMDCs has been reported experimentally. Here, we report the experimental study on Fermi level pinning of monolayer MoS 2 and MoTe 2 by interpreting the thermionic emission results. We also quantitatively compared our results with the theoretical simulation results of the monolayer structure as well as the experimental results of the bulk structure. We measured the pinning factor S to be 0.11 and -0.07 for monolayer MoS 2 and MoTe 2 , respectively, suggesting a much stronger Fermi level pinning effect, a Schottky barrier height (SBH) lower than that by theoretical prediction, and interestingly similar pinning energy levels between monolayer and bulk MoS 2 . Our results further imply that metal work functions have very little influence on contact properties of 2D-material-based devices. Moreover, we found that R c is exponentially proportional to SBH, and these processing parameters can be controlled sensitively upon chemical doping into the 2D materials. These findings provide a practical guideline for depinning Fermi level at the 2D interfaces so that polarity control of TMDC-based semiconductors can be achieved efficiently.

  17. Analyses of physics specimens in fuel pins 1 and 2 irradiated in the Dounreay Prototype Fast Reactor

    International Nuclear Information System (INIS)

    Raman, S.; Broadhead, B.L.; Dickens, J.K.; Walker, R.L.; Botts, J.L.

    1992-01-01

    The United States and the United Kingdom have been engaged in a joint research program in which samples of fissile and fertile actinides have been incorporated into three separate fuel pins and irradiated in the Dounreay Prototype Fast Reactor in Scotland. The actinides in the second fuel pin were studied for fission-product decay, specifically to obtain absolute yields of 137 Cs. Comparisons with calculated yields result in ratios of measured to calculated between 0.67 (±0.05) and 1.09 (±0.18). Plotting of experimental versus calculated values of 137 Cs indicated that the assumed flux levels were some 5 to 20% overestimated. This flux level information will be useful in the forthcoming analysis of the last fuel pin, FP-4

  18. Some possible effects of periodic pinning in high T csuperconductors

    Science.gov (United States)

    Rezlescu, N.; Anghelache, R.; Ciobotaru, I.; Puha, I.

    1997-04-01

    We are assuming that the pinning points could be created in the center of each unit cell of the planar superconducting lattice. The existence of periodic pinning suggests a particular dynamics of vortices in the mixed state of 2D and 3D high Tcsuperconductors. Such a moving mechanism may be studied using a planar Potts model. We used such a model to perform some numerical simulations focusing on the melting of the Abrikosov lattice of vortices in a system of Josephson arrays of superconducting grains. A Monte Carlo analysis on the resulting hamiltonian in a field given by a starting filling factor off = 1/2 exhibits two phase transitions, in both 2D and 3D. The 2D model gives the critical temperatures[formula]and[formula]. The~3D one gives[formula]and[formula]. The numerical estimation of the Challa parameters for both transitions indicates their continuous nature in both 2D and 3D versions of this model. The results suggest that, below Tc1, the superconductor is in the Meissner phase, between Tc1and Tmit is in the mixed state and above Tmit is in the melted flux state, i.e. technological normal state.

  19. FFTF metal fuel pin fabrication

    International Nuclear Information System (INIS)

    Dittmer, J.O.; Benecke, M.W.; Feigenbutz, L.V.

    1989-01-01

    A major new initiative to develop, irradiate, and qualify a binary uranium/zirconium metal-fuel system in the Fast Flux Test Facility (FFTF) has been implemented by the Westinghouse Hanford Company for the US Department of Energy. Metal-fuel test assemblies have been designed and fabricated, and are now being irradiated in FFTF to provide the data needed to support the potential use of binary metal fuels in FFTF and other liquid-metal reactors. These development efforts support licensing activities for metal-fuel use in near-term advanced liquid-metal reactors

  20. Whole-Pin Furnace system: An experimental facility for studying irradiated fuel pin behavior under potential reactor accident conditions

    International Nuclear Information System (INIS)

    Liu, Y.Y.; Tsai, H.C.; Donahue, D.A.; Pushis, D.O.; Savoie, F.E.; Holland, J.W.; Wright, A.E.; August, C.; Bailey, J.L.; Patterson, D.R.

    1990-05-01

    The whole-pin furnace system is a new in-cell experimental facility constructed to investigate how irradiated fuel pins may fail under potential reactor accident conditions. Extensive checkouts have demonstrated excellent performance in remote operation, temperature control, pin breach detection, and fission gas handling. The system is currently being used in testing of EBIR-II-irradiated Integral Fast Reactor (IFR) metal fuel pins; future testing will include EBR-II-irradiated mixed-oxide fuel pins. 7 refs., 4 figs

  1. Experimental and simulation study of missing matching peaks in Nb thinfilms with square pinning arrays

    Czech Academy of Sciences Publication Activity Database

    Cao, R.; Horng, L.; Wu, T.C.; Lin, J.C.; Wu, J.C.; Yang, T.-J.; Koláček, Jan

    2011-01-01

    Roč. 109, č. 8 (2011), "083920-1"-"083920-5" ISSN 0021-8979 R&D Projects: GA ČR(CZ) GAP204/11/0015; GA MŠk(CZ) ME10069 Institutional research plan: CEZ:AV0Z10100521 Keywords : critical currents * flux pinning * galvanomagnetic effects * interstitials * metallic thin films * niobium * superconducting thin films Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.168, year: 2011

  2. The ac effect of vortex pinning in the arrays of defect sites on Nb films

    Czech Academy of Sciences Publication Activity Database

    Wu, T.C.; Horng, L.; Wu, J.C.; Hsiao, C.W.; Koláček, Jan; Yang, T.-J.

    2006-01-01

    Roč. 99, č. 8 (2006), 08M515/1-08M515/3 ISSN 0021-8979 R&D Projects: GA ČR(CZ) GA202/05/0173 Institutional research plan: CEZ:AV0Z10100521 Keywords : superconducting vortex dynamics * flux pinning * vortex-motion control device Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.316, year: 2006

  3. Whole core pin-by-pin coupled neutronic-thermal-hydraulic steady state and transient calculations using COBAYA3 code

    International Nuclear Information System (INIS)

    Jimenez, J.; Herrero, J. J.; Cuervo, D.; Aragones, J. M.

    2010-10-01

    Nowadays coupled 3-dimensional neutron kinetics and thermal-hydraulic core calculations are performed by applying a radial average channel approach using a meshing of one quarter of assembly in the best case. This approach does not take into account the subchannels effects due to the averaging of the physical fields and the loose of heterogeneity in the thermal-hydraulic model. Therefore the models do not have enough resolution to predict those subchannels effects which are important for the fuel design safety margins, because it is in the local scale, where we can search the hottest pellet or the maximum heat flux. The Polytechnic University of Madrid advanced multi-scale neutron-kinetics and thermal-hydraulics methodologies being implemented in COBAYA3 include domain decomposition by alternate core dissections for the local 3-dimensional fine-mesh scale problems (pin cells/subchannels) and an analytical nodal diffusion solver for the coarse mesh scale coupled with the thermal-hydraulic using a model of one channel per assembly or per quarter of assembly. In this work, we address the domain decomposition by the alternate core dissections methodology applied to solve coupled 3-dimensional neutronic-thermal-hydraulic problems at the fine-mesh scale. The neutronic-thermal-hydraulic coupling at the cell-subchannel scale allows the treatment of the effects of the detailed thermal-hydraulic feedbacks on cross-sections, thus resulting in better estimates of the local safety margins at the pin level. (Author)

  4. Development of a fast pin-by-pin transport solver in ARCADIA registered

    International Nuclear Information System (INIS)

    Geemert, R. van

    2009-01-01

    For satisfaction of future global customer needs, dedicated efforts are being coordinated internationally and pursued continuously at AREVA NP. The currently ongoing CONVERGENCE project is committed to the development of the ARCADIA registered next generation core simulation software package. ARCADIA registered will be put to global use by all AREVA NP business regions, for the entire spectrum of core design processes, licensing computations and safety studies. As part of the currently ongoing trend towards more sophisticated neutronics methodologies, an SP 3 nodal transport concept (van Geemert 2008) has been developed for ARTEMIS (Hobson 2008) which is the steady-state and transient core simulation part of ARCADIA registered . For enabling a high computational performance, the SP 3 calculations are accelerated by applying multi-level coarse mesh rebalancing (van Geemert 2006). In the current implementation, SP 3 is typically about 1.4 times as expensive computationally as SP 1 (diffusion). The developed SP 3 solution concept is foreseen as the future computational workhorse for many-group 3D pin-by-pin full core computations by ARCADIA registered . With the entire numerical workload being highly parallelizable through domain decomposition techniques, associated CPU-time requirements that adhere to the efficiency needs in the nuclear industry can be expected to become feasible in the near future. The accuracy enhancement obtainable by using SP 3 instead of SP 1 has been verified by a detailed comparison of ARTEMIS 16-group pin-by-pin SP N results with KAERI's DeCart reference results (Kozlowski 2003) for the 2D pin-by-pin Purdue UO 2 /MOX benchmark. Within the associated pin-by-pin grid, large pin-to-pin variations in cross-section values occur due to the explicit modelling of guide tubes, gadolinium pins as well as the heterogeneous distribution of MOX assemblies and UO 2 assemblies featuring significantly different burnups. With a pin-by-pin grid as

  5. PINS Testing and Modification for Explosive Identification

    Energy Technology Data Exchange (ETDEWEB)

    E.H. Seabury; A.J. Caffrey

    2011-09-01

    The INL's Portable Isotopic Neutron Spectroscopy System (PINS)1 non-intrusively identifies the chemical fill of munitions and sealed containers. PINS is used routinely by the U.S. Army, the Defense Threat Reduction Agency, and foreign military units to determine the contents of munitions and other containers suspected to contain explosives, smoke-generating chemicals, and chemical warfare agents such as mustard and nerve gas. The objects assayed with PINS range from softball-sized M139 chemical bomblets to 200 gallon DOT 500X ton containers. INL had previously examined2 the feasibility of using a similar system for the identification of explosives, and based on this proof-of-principle test, the development of a dedicated system for the identification of explosives in an improvised nuclear device appears entirely feasible. INL has been tasked by NNSA NA-42 Render Safe Research and Development with the development of such a system.

  6. Fabrication drawings of fuel pins for FUJI project among PSI, JNC and NRG. Revised version 2

    International Nuclear Information System (INIS)

    Ozawa, Takayuki; Nakazawa, Hiroaki; Abe, Tomoyuki; Nagayama, Masahiro

    2002-10-01

    Irradiation tests and post-irradiation examinations in the framework of JNC-PSI-NRG collaboration project will be performed in 2003-2005. Irradiation fuel pins will be fabricated by the middle of 2003. The fabrication procedure for irradiation fuel pins has been started in 2001. Several fabrication tests and qualification tests in JNC and PSI (Paul Scherrer Institut, Switzerland) have been performed before the fuel pin fabrication. According to the design assignment between PSI and JNC in the frame of this project, PSI should make specification documents for the fuel pellet, the sphere-pac fuel particles, the vipac fuel fragments, and the fuel segment fabrication. JNC should make the fabrication drawings for irradiation pins. JNC has been performed the fuel design in cooperation with PSI and NRG (Nuclear Research and Consultancy Group, Holland). In this project, the pelletized fuel, the sphere-pac fuel, and the vipac fuel will be simultaneously irradiated on HFR (High Flux Reactor, Holland). The fabrication drawings have been made under the design assignment with PSI, and consist of the drawings of MOX pellet, thermal insulator pellet, pin components, fuel segments, and the constructed pin. The fabrication drawings were approved in October 2001, but after that, the optimization of specifications was discussed and agreed among all partners. According to this agreement, the fabrication drawings were revised in January 2002. After the earlier revision, the shape of particle retainer to be made by PSI was modified from its drawing beforehand delivered. In this report, the fabrication drawings revised again will be shown, and the fabrication procedure (welding Qualification Tests) will be modified in accordance with the result of discussion on the 3rd technical meeting held in September 2002. These design works have been performed in Fuel Design and Evaluation Group, Plutonium Fuel Fabrication Division, Plutonium Fuel Center under the commission of Plutonium Fuel

  7. Enhancement of the forced convective heat transfer on mini pin fin heat sinks with micro spiral fins

    Science.gov (United States)

    Khonsue, Osot

    2018-02-01

    This research is an experimental study on the characteristics of heat transfer and pressure drop in mini heat sinks using air as the working fluid. The experiments were performed under a constant heat flux ranging from 9.132-13.698 kW/m2 and the air Reynolds number range 322-1982. Three different types of mini heat sinks were rectangle pin fins, cylindrical pin fins, and spiral pin fins with 36x28x9 mm and 5 mm fins high. There were 63 fins altogether and all were made of aluminum. The results showed that the characteristics of the temperature of heat sink of spiral pin fins was the least. Meanwhile the average heat transfer coefficient and Nusselt number of spiral pin fins were the most . Regarding the pressure drop, the rectangular pin fins was the least. The results of this study can be used to guide the design and development of electronic devices cooling system with forced convective heat transfer for higher performance in the future.

  8. pi-N charge exchange and pi(+)-pi(0) scattering at low energies

    OpenAIRE

    Pocanic, D.; Frlez, E.

    1997-01-01

    pi-N and pi-pi interactions near threshold are uniquely sensitive to the chiral symmetry breaking part of the strong interaction. The pi-N sigma-term value with its implications for nucleon quark structure and the recent controversy concerning the size of the scalar quark condensate have renewed the experimental interest in these two fundamental systems. We report new differential cross sections for the reaction $pi^-p \\to \\pi^0n$ at 27.5 MeV pion incident kinetic energy, measured between $\\t...

  9. Kinetic roughening and pinning of coupled precursor and impregnation fronts in porous media

    International Nuclear Information System (INIS)

    Balankin, Alexander S.; Garcia Paredes, Rafael; Marquez Gonsalez, Jesus; Susarrey Huerta, Orlando; Morales Matamoros, Daniel; Castrejon Vacio, Fernando

    2006-01-01

    In the paper wetting experiments at low evaporation rate, after a short Washburn regime the film flow of filtered water overtakes the main impregnation front. Accordingly, we study the kinetic roughening dynamics and pinning of two strongly coupled fronts moving in different papers. We find that the kinetic roughening dynamics of precursor and main fronts belongs to different universality classes, nevertheless, at the final stage the distance between the fronts decrease until both fronts are pinned in the same configuration z P (x,y), the scaling properties of which are determined by the long-range correlations in the pore network

  10. Computational and analytical comparison of flux discretizations for the semiconductor device equations beyond Boltzmann statistics

    Science.gov (United States)

    Farrell, Patricio; Koprucki, Thomas; Fuhrmann, Jürgen

    2017-10-01

    We compare three thermodynamically consistent numerical fluxes known in the literature, appearing in a Voronoï finite volume discretization of the van Roosbroeck system with general charge carrier statistics. Our discussion includes an extension of the Scharfetter-Gummel scheme to non-Boltzmann (e.g. Fermi-Dirac) statistics. It is based on the analytical solution of a two-point boundary value problem obtained by projecting the continuous differential equation onto the interval between neighboring collocation points. Hence, it serves as a reference flux. The exact solution of the boundary value problem can be approximated by computationally cheaper fluxes which modify certain physical quantities. One alternative scheme averages the nonlinear diffusion (caused by the non-Boltzmann nature of the problem), another one modifies the effective density of states. To study the differences between these three schemes, we analyze the Taylor expansions, derive an error estimate, visualize the flux error and show how the schemes perform for a carefully designed p-i-n benchmark simulation. We present strong evidence that the flux discretization based on averaging the nonlinear diffusion has an edge over the scheme based on modifying the effective density of states.

  11. Surface flux density distribution characteristics of bulk high-T c superconductor in external magnetic field

    International Nuclear Information System (INIS)

    Nishikawa, H.; Torii, S.; Yuasa, K.

    2005-01-01

    This paper describes the measured results of the two-dimensional flux density distribution of a YBCO bulk under applied AC magnetic fields with various frequency. Melt-processed oxide superconductors have been developed in order to obtain strong pinning forces. Various electric mechanical systems or magnetic levitation systems use those superconductors. The major problem is that cracks occur because the bulk superconductors are brittle. The bulk may break in magnetizing process after cracks make superconducting state instable. The trapped flux density and the permanent current characteristics of bulk superconductors have been analyzed, so as to examine the magnetizing processes or superconducting states of the bulk. In those studies, the two-dimensional surface flux density distributions of the bulk in static fields are discussed. On the other hand, the distributions in dynamic fields are little discussed. We attempted to examine the states of the bulk in the dynamic fields, and made a unique experimental device which has movable sensors synchronized with AC applied fields. As a result, the two-dimensional distributions in the dynamic fields are acquired by recombining the one-dimensional distributions. The dynamic states of the flux of the bulk and the influences of directions of cracks are observed from the distributions. In addition, a new method for measuring two-dimensional flux density distribution under dynamic magnetic fields is suggested

  12. The effect of substrate conduction on boiling data on pin-fin heat sinks

    International Nuclear Information System (INIS)

    McNeil, D.A.; Raeisi, A.H.; Kew, P.A.; Hamed, R.S.

    2015-01-01

    Heat-transfer experiments for a copper heat sink containing pin-fins with a cross section of 1 mm by 1 mm and a height of 1 mm have been reported previously. The pin-fins were manufactured on a 5 mm thick, 50 mm square base plate in a square, in-line arrangement with a pitch of 2 mm. Data were produced while boiling R113 and water at atmospheric pressure. The heat sink was heated from below through a 5 mm thick aluminium wall by an electrical heating method that is normally associated with the uniform heat flux boundary condition. However, variations in the heat-transfer coefficient and the liquid subcooling interacted with the high thermal conductivity of the aluminium and copper materials to produce a near isothermal wall boundary condition. Thus, heat conduction effects had to be taken into account when determining the heat-flux distribution required in the analysis of the data. Many experiments like these have used the uniform heat-flux assumption to analyse the data. The discrepancies produced from this approach are explored. Single-phase flows across a pin-fin surface produce a reasonably uniform distribution of heat-transfer coefficient. However, the liquid temperature increases as it moves across the heat sink. This produces a non-uniform heat flux distribution at the solid–fluid interface. The uniform heat-flux assumption is shown to lead to errors of ±17% in the estimation of the heat-transfer coefficient. The original boiling flow experiments found that the water data were confined and that the majority of the R113 data were not. The confined and unconfined data are processed with the thermal conduction in the walls taken into account and by assuming a uniform heat flux at the solid–fluid interface. The uniform heat-flux distribution analysis for unconfined flows shows errors in the heat-transfer coefficient to be typically ±17%. Confined flows produce smaller errors, typically ±12%, close to the onset of nucleation. However, these damp out

  13. Micro-alloying and the toughness of glasses: Modeling with pinned particles

    Science.gov (United States)

    Dasgupta, Ratul; Mishra, Pankaj; Procaccia, Itamar; Samwer, Konrad

    2013-05-01

    The usefulness of glasses, and particularly of metallic glasses, in technological applications is often limited by their toughness, (which is defined as the area under the stress vs. strain curve before plastic yielding). Recently, toughness was found to increase significantly by the addition of small concentrations of foreign atoms that act as pinning centers. We model this phenomenon at zero temperature and quasi-static straining with randomly positioned particles that participate in the elastic deformation, but are pinned in the non-affine return to mechanical equilibrium. We find a very strong effect on toughness via the increase of both the shear modulus and the yield stress as a function of the density of pinned particles. Understanding the results calls for analyzing separately the elastic, or "Born term", and the contributions of the "excess modes" that result from glassy disorder. Finally, we present a scaling theory that collapses the data on one universal curve as a function of rescaled variables.

  14. On the pinned field image binarization for signature generation in image ownership verification method

    Directory of Open Access Journals (Sweden)

    Chang Hsuan

    2011-01-01

    Full Text Available Abstract The issue of pinned field image binarization for signature generation in the ownership verification of the protected image is investigated. The pinned field explores the texture information of the protected image and can be employed to enhance the watermark robustness. In the proposed method, four optimization schemes are utilized to determine the threshold values for transforming the pinned field into a binary feature image, which is then utilized to generate an effective signature image. Experimental results show that the utilization of optimization schemes can significantly improve the signature robustness from the previous method (Lee and Chang, Opt. Eng. 49 (9, 097005, 2010. While considering both the watermark retrieval rate and the computation speed, the genetic algorithm is strongly recommended. In addition, compared with Chang and Lin's scheme (J. Syst. Softw. 81 (7, 1118-1129, 2008, the proposed scheme also has better performance.

  15. Forced convective performance of perforated circular pin-fin heat sinks

    Science.gov (United States)

    Wen, Mao-Yu; Yeh, Cheng-Hsiung

    2017-05-01

    This study examines heat transfer performance under forced convection for two different types (Type A and Type B) of pin-fin heat sinks with and without a hollow in the heated base. The effects of the Reynolds number, heights of the fin and base plate, finning factor, heat sink porosity and perforated base plate on the heat-transfer coefficient, fin effectiveness and pressure drop were investigated and evaluated. The present study strongly suggests the use of a small hollow [( D h / D b ) plate of the pin-fin heat sink. In order to obtain insight into the fluid flow phenomena, flow visualization was also made to observe the detailed fluid flow characteristics of the present pin-fin heat sinks.

  16. Increasing FSW join strength by optimizing feed rate, rotating speed and pin angle

    Science.gov (United States)

    Darmadi, Djarot B.; Purnowidodo, Anindito; Siswanto, Eko

    2017-10-01

    Principally the join in Friction Stir Welding (FSW) is formed due to mechanical bonding. At least there are two factors determines the quality of this join, first is the temperature in the area around the interface and secondly the intense of mixing forces in nugget zone to create the mechanical bonding. The adequate temperature creates good flowability of the nugget zone and an intensive mixing force produces homogeneous strong bonding. Based on those two factors in this research the effects of feed rate, rotating speed and pin angle of the FSW process to the tensile strength of resulted join are studied. The true experimental method was used. Feed rate was varied at 24, 42, 55 and 74 mm/minutes and from the experimental results, it can be concluded that the higher feed rate decreases the tensile strength of weld join and it is believed due to the lower heat embedded in the material. Inversely, the higher rotating speed increases the join’s tensile strength as a result of higher heat embedded in base metal and higher mixing force in the nugget zone. The rotating speed were 1842, 2257 and 2904 RPMs. The pin angle determines the direction of mixing force. With variation of pin angle: 0°, 4°, 8° and 12° the higher pin angle generally increases the tensile strength because of more intensive mixing force. For 12° pin angle the lower tensile strength is found since the force tends to push out the nugget area from the joint gap.

  17. Pinning Susceptibility at the Jamming Transition

    Science.gov (United States)

    Graves, Amy; Padgett, Elliot; Goodrich, Carl; Liu, Andrea

    2013-03-01

    Jamming in the presence of fixed or pinned obstacles, representing quenched disorder, is a situation of both practical and theoretical interest. We study the jamming of soft, bidisperse discs in which a subset of discs are pinned while the remaining particles equilibrate around them at a given volume fraction. The obstacles provide a supporting structure for the jammed configuration which not only lowers the jamming threshold, ϕJ, but affects the coordination number and other parameters of interest as the critical point is approached. In the limit of low obstacle density, one can calculate a pinning susceptibility χP, analogous to the magnetic susceptibility, with obstacle density playing the role of the magnetic field. The pinning susceptibility is thus expected to diverge in the thermodynamic limit as χP ~| ϕ -ϕJ | -γP . Finite-size scaling calculations allow us to confirm this and calculate the critical exponent, γP. Acknowledgement is made to the Donors of the Petrolium Research Fund administered by the American Chemical Society, Swarthmore College's Eugene M. Lang Faculty Fellowship, NSF grant DMR-1062638 and DOE grant DE-FG02-05ER46199.

  18. Synchronizability on complex networks via pinning control

    Indian Academy of Sciences (India)

    Synchronizability on complex networks via pinning control. YI LIANG1,2 and XINGYUAN WANG1,∗. 1Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology,. Dalian 116024, China. 2Department of Electronics and Information Engineering, Yili Normal College,. Yining 835000, China. ∗.

  19. Radiographic examination methods for fuel pins

    International Nuclear Information System (INIS)

    Smirnov, V.P.; Dvoretskii, V.G.

    1987-11-01

    To study the fast neutron reactor fuel pins structure the NIIAR Institute used x diffraction, neutronic radiography and autoradiographies. The two first methods are used for internal macrostructure studies, the third method for the plutonium and uranium radial distribution. These methods and the main results are indicated in this document [fr

  20. Physicist pins hopes on particle collider

    CERN Multimedia

    2007-01-01

    Physicist pins hopes on particle collider By Deseret Morning News Published: Monday, Dec. 31, 27 12:4 a.m. MST FONT Scott Thomas, a 187 State University graduate, is working at the frontiers of science. The theoretical physicist is crafting ways to extract fundamental secrets that seem certain to be uncovered by the Large Hadron Collider.

  1. Video Meteor Fluxes

    Science.gov (United States)

    Campbell-Brown, M. D.; Braid, D.

    2011-01-01

    estimate the flux (Love & Brownlee, 1993); here the physical area of the detector is well known, but the masses depend strongly on the unknown velocity distribution. In the same size range, Thomas & Netherway (1989) used the narrow-beam radar at Jindalee to calculate the flux of sporadics. In between these very large and very small sizes, a number of video and photographic observations were reduced by Ceplecha (2001). These fluxes were calculated (details are given in Ceplecha, 1988) taking the Halliday et al. (1984) MORP fireball fluxes, slightly corrected in mass, as a calibration, and adjusting the flux of small cameras to overlap with the number/mass relation from that work.

  2. Method for producing microstructured templates and their use in providing pinning enhancements in superconducting films deposited thereon

    Science.gov (United States)

    Aytug, Tolga; Paranthaman, Mariappan Parans; Polat, Ozgur

    2013-07-16

    The present invention relates to a method for producing a phase-separated layer useful as a flux pinning substrate for a superconducting film, wherein the method includes subjecting at least a first and a second target material to a sputtering deposition technique in order that a phase-separated layer is deposited epitaxially on a primary substrate containing an ordered surface layer. The invention is also directed to a method for producing a superconducting tape containing pinning defects therein by depositing a superconducting film on a phase-separated layer produced by the method described above.

  3. Thermal management of electronics using phase change material based pin fin heat sinks

    International Nuclear Information System (INIS)

    Baby, R; Balaji, C

    2012-01-01

    This paper reports the results of an experimental study carried out to explore the thermal characteristics of phase change material based heat sinks for electronic equipment cooling. The phase change material (PCM) used in this study is n – eicosane. All heat sinks used in the present study are made of aluminium with dimensions of 80 × 62 mm 2 base with a height of 25 mm. Pin fins acts as the thermal conductivity enhancer (TCE) to improve the distribution of heat more uniformly as the thermal conductivity of the PCM is very low. A total of three different pin fin heat sink geometries with 33, 72 and 120 pin fins filled with phase change materials giving rise to 4%, 9% and 15% volume fractions of the TCE respectively were experimentally investigated. Baseline comparisons are done with a heat sink filled with PCM, without any fin. Studies are conducted for heat sinks on which a uniform heat load is applied at the bottom for the finned and unfinned cases. The effect of pin fins of different volume fractions with power levels ranging from 4 to 8 W corresponding to a heat flux range of 1. 59 to 3.17 kW/m 2 , was explored in this paper. The volume fraction of the PCM (PCM volume / (Total volume – fin volume)) is also varied as 0. 3, 0.6 and 1 to determine the effect of PCM volume on the overall performance of the electronic equipment.

  4. Vortex matter in the presence of an array of pinning centers of variable strength

    International Nuclear Information System (INIS)

    Nunes, J.S.; Zadorosny, R.; Oliveira, A.A.M.; Lepienski, C.M.; Patino, E.J.; Blamire, M.G.; Ortiz, W.A.

    2008-01-01

    This contribution reports on the magnetic response of a 200 nm thick Nb film, pierced with a set of 900 columnar indentations of nearly triangular cross section, forming a square lattice. The column effective diameter is 1 μm and the array lattice parameter is 10 μm. To probe the interaction of vortex matter with the array of antidots, we have excited the sample with an AC-field, so that flux trapped by the columns could be unpinned and admitted into the superconducting sea surrounding the defects. An order-disorder line was determined for this system, with a kink separating two regimes, suggesting a crossover from the efficient pinning regime, at lower temperatures, to a temperature-induced depinning. To exploit the influence of pinning efficiency on vortex dynamics, we have determined the order-disorder line at different angles between the applied field and the plane of the film. A plot of the field component perpendicular to the film versus temperature, gives a collapsed response near T c , which splits for lower temperatures, as a consequence of pinning weakening due to the component of the applied AC-field perpendicular to the columns. Consistently, the kink tends to progressively disappear as the pinning strength decreases

  5. Pinning control of complex networked systems synchronization, consensus and flocking of networked systems via pinning

    CERN Document Server

    Su, Housheng

    2013-01-01

    Synchronization, consensus and flocking are ubiquitous requirements in networked systems. Pinning Control of Complex Networked Systems investigates these requirements by using the pinning control strategy, which aims to control the whole dynamical network with huge numbers of nodes by imposing controllers for only a fraction of the nodes. As the direct control of every node in a dynamical network with huge numbers of nodes might be impossible or unnecessary, it’s then very important to use the pinning control strategy for the synchronization of complex dynamical networks. The research on pinning control strategy in consensus and flocking of multi-agent systems can not only help us to better understand the mechanisms of natural collective phenomena, but also benefit applications in mobile sensor/robot networks. This book offers a valuable resource for researchers and engineers working in the fields of control theory and control engineering.   Housheng Su is an Associate Professor at the Department of Contro...

  6. Post irradiation examination on test fuel pins for PWR

    International Nuclear Information System (INIS)

    Fogaca Filho, N.; Ambrozio Filho, F.

    1981-01-01

    Certain aspects of irradiation technology on test fuel pins for PWR, are studied. The results of post irradiation tests, performed on test fuel pins in hot cells, are presented. The results of the tests permit an evaluation of the effects of irradiation on the fuel and cladding of the pin. (Author) [pt

  7. Primary hip spica with crossed retrograde intramedullary rush pins ...

    African Journals Online (AJOL)

    Bursitis and penetration of pins at the site of Rush pin insertion is a complication associated with this method of treatment. Conclusion: Closed reduction and internal fixation with crossed Rush pins was a superior treatment method in terms of early weight bearing and restoration of normal anatomy. Keywords: Femoral ...

  8. Estimation of wood properties using pin pushing in method with various shapes of the penetration pin

    Directory of Open Access Journals (Sweden)

    Michal Kloiber

    2009-01-01

    Full Text Available The existing penetration methods for the identification of the density of wood that forms a part of structures do not make it possible to describe the density in the entire element profile but only on its surface. However, wood density changes throughout the profile which affects the accuracy of the density determination. The instruments used until now based on the principle of a pin shot into the material thus needed to be supplemented with a test during which the pin would be pushed at least to the centre of the measured element. Pins of 3 mm in diameter were manufactured with a special jig fastening them to a universal testing machine. Using the testing machine, the force required to push the pin in was measured at a constant travel speed. It has been found out that the mechanical work needed for the pin penetration correlates very well with the wood density determined in the surroundings of the place where the pin was pushed in.

  9. Genome-wide identification and evolution of the PIN-FORMED (PIN) gene family in Glycine max.

    Science.gov (United States)

    Liu, Yuan; Wei, Haichao

    2017-07-01

    Soybean (Glycine max) is one of the most important crop plants. Wild and cultivated soybean varieties have significant differences worth further investigation, such as plant morphology, seed size, and seed coat development; these characters may be related to auxin biology. The PIN gene family encodes essential transport proteins in cell-to-cell auxin transport, but little research on soybean PIN genes (GmPIN genes) has been done, especially with respect to the evolution and differences between wild and cultivated soybean. In this study, we retrieved 23 GmPIN genes from the latest updated G. max genome database; six GmPIN protein sequences were changed compared with the previous database. Based on the Plant Genome Duplication Database, 18 GmPIN genes have been involved in segment duplication. Three pairs of GmPIN genes arose after the second soybean genome duplication, and six occurred after the first genome duplication. The duplicated GmPIN genes retained similar expression patterns. All the duplicated GmPIN genes experienced purifying selection (K a /K s < 1) to prevent accumulation of non-synonymous mutations and thus remained more similar. In addition, we also focused on the artificial selection of the soybean PIN genes. Five artificially selected GmPIN genes were identified by comparing the genome sequence of 17 wild and 14 cultivated soybean varieties. Our research provides useful and comprehensive basic information for understanding GmPIN genes.

  10. The Half-Pin and the Pin Tract: A Survey of the Limb Lengthening and Reconstruction Society

    Science.gov (United States)

    2013-09-01

    Heikkila J, Magyar G, Toksvig-Larsen S, Giannini S. Fixation strength and pin tract infection of hydroxyapatite-coated tapered pins. Clin Orthop. 2001...Enhanced fixation with hydroxyapatite coated pins. Clin Orthop. 1998;(346):171-177. 13. Magyar G, Toksvig-Larsen S, Moroni A. Hydroxyapatite coating

  11. Prolyl isomerase Pin1 is highly expressed in Her2-positive breast cancer and regulates erbB2 protein stability

    Directory of Open Access Journals (Sweden)

    Lu Kun

    2008-12-01

    Full Text Available Abstract Overexpression of HER-2/Neu occurs in about 25–30% of breast cancer patients and is indicative of poor prognosis. While Her2/Neu overexpression is primarily a result of erbB2 amplification, it has recently been recognized that erbB2 levels are also regulated on the protein level. However, factors that regulate Her2/Neu protein stability are less well understood. The prolyl isomerase Pin1 catalyzes the isomerization of specific pSer/Thr-Pro motifs that have been phosphorylated in response to mitogenic signaling. We have previously reported that Pin1-catalyzed post-phosphorylational modification of signal transduction modulates the oncogenic pathways downstream from c-neu. The goal of this study was to examine the expression of prolyl isomerase Pin1 in human Her2+ breast cancer, and to study if Pin1 affects the expression of Her2/Neu itself. Methods Immunohistochemistry for Her2 and Pin1 were performed on two hundred twenty-three human breast cancers, with 59% of the specimen from primary cancers and 41% from metastatic sites. Pin1 inhibition was achieved using siRNA in Her2+ breast cancer cell lines, and its effects were studied using cell viability assays, immunoblotting and immunofluorescence. Results Sixty-four samples (28.7% stained positive for Her2 (IHC 3+, and 54% (122/223 of all breast cancers stained positive for Pin1. Of the Her2-positive cancers 40 (62.5% were also Pin1-positive, based on strong nuclear or nuclear and cytoplasmic staining. Inhibition of Pin1 via RNAi resulted in significant suppression of Her2-positive tumor cell growth in BT474, SKBR3 and AU565 cells. Pin1 inhibition greatly increased the sensitivity of Her2-positive breast cancer cells to the mTOR inhibitor Rapamycin, while it did not increase their sensitivity to Trastuzumab, suggesting that Pin1 might act on Her2 signaling. We found that Pin1 interacted with the protein complex that contains ubiquitinated erbB2 and that Pin1 inhibition accelerated erbB2

  12. Irradiation of a 19 pin subassembly with mixed carbide fuel in KNK II

    Energy Technology Data Exchange (ETDEWEB)

    Geitthoff, D. (Kernforschungszentrum Karlsruhe GmbH (Germany). Inst. fuer Materialforschung 3); Muehling, G. (Kernforschungszentrum Karlsruhe GmbH (Germany). European Fast Reactor); Richter, K. (Europaeisches Inst. fuer Transurane, Karlsruhe (Germany))

    1992-06-01

    The presentation deals with the fabrication, irradiation and nondestructive postirradiation examinations of LMR fuel pins with mixed (U, PU)-carbide fuels. The mixed carbide fuel was fabricated by the European Institute of Transuranium Elements using various fabrication procedures. Fuel composition varied therefore in a wide range of tolerances with respect to oxygen and phase content and microstructure. The 19 carbide pins were irradiated in the fast neutron flux of the KNK II reactor to a burn-up of about 7 at% without any failure in the centre of a KNK 'carrier element' at a maximum linear rating of 800 W/cm. After dismantling in the Hot Cells of KfK nondestructive examinations were carried out comprising dimensional controls, radiography, [gamma]-scanning and eddy-current testing. The results indicate differences in fuel behaviour with respect to composition of the fuel. (orig.).

  13. Low-field vortex pinning model for undoped sintered MgB2 powders

    International Nuclear Information System (INIS)

    Agassi, Y D

    2011-01-01

    Sintered MgB 2 powders constitute a porous ensemble of irregularly shaped agglomerates of tightly packed grains. The low-field critical current density in such powders was experimentally observed to scale with the inverse of the average agglomerate size. Motivated by this observation we consider a flux pinning model which accounts for the MgB 2 powder porosity by focusing on a single finite-size agglomerate size. According to the model the observed critical current density dependence on the agglomerate size reflects the outward pull exerted on a vortex that is pinned in proximity to the agglomerate edges. The calculated critical current density replicates the observed scaling within agglomerate-size bounds. Implications of the model are discussed.

  14. Elementary pinning force for a superconducting vortex

    International Nuclear Information System (INIS)

    Hyun, O.B.; Finnemore, D.K.; Schwartzkopf, L.; Clem, J.R.

    1987-01-01

    The elementary pinning force f/sub p/ has been measured for a single vortex trapped in one of the superconducting layers of a cross-strip Josephson junction. At temperatures close to the transition temperature the vortex can be pushed across the junction by a transport current. The vortex is found to move in a small number of discrete steps before it exits the junction. The pinning force for each site is found to be asymmetric and to have a value of about 10/sup -6/ N/m at the reduced temperature, t = T/T/sub c/ = 0.95. As a function of temperature, f/sub p/ is found to vary approximately as (1-t)/sup 3/2/. .AE

  15. Top-nozzle mounted replacement guide pin assemblies

    International Nuclear Information System (INIS)

    Gilmore, C.B.; Andrews, W.H.

    1993-01-01

    A replacement guide pin assembly is provided for aligning a nuclear fuel assembly with an upper core plate of a nuclear reactor core. The guide pin assembly includes a guide pin body having a radially expandable base insertable within a hole in the top nozzle, a ferrule insertable within the guide pin base and capable of imparting a radially and outwardly directed force on the expandable base to expand it within the hole of the top nozzle and thereby secure the guide pin body to the top nozzle in response to a predetermined displacement of the ferrule relative to the guide pin body along its longitudinal axis, and a lock screw interfitted with the ferrule and threaded into the guide pin body so as to produce the predetermined displacement of the ferrule. (author)

  16. Modeling the instability behavior of thin film devices: Fermi Level Pinning

    Science.gov (United States)

    Moeini, Iman; Ahmadpour, Mohammad; Gorji, Nima E.

    2018-05-01

    We investigate the underlying physics of degradation/recovery of a metal/n-CdTe Schottcky junction under reverse or forward bias stressing conditions. We used Sah-Noyce-Shockley (SNS) theory to investigate if the swept of Fermi level pinning at different levels (under forward/reverse bias) is the origin of change in current-voltage characteristics of the device. This theory is based on Shockley-Read-Hall recombination within the depletion width and takes into account the interface defect levels. Fermi Level Pinning theory was primarily introduced by Ponpon and developed to thin film solar cells by Dharmadasa's group in Sheffield University-UK. The theory suggests that Fermi level pinning at multiple levels occurs due to high concentration of electron-traps or acceptor-like defects at the interface of a Schottky or pn junction and this re-arranges the recombination rate and charage collection. Shift of these levels under stress conditions determines the change in current-voltage characteristics of the cell. This theory was suggested for several device such as metal/n-CdTe, CdS/CdTe, CIGS/CdS or even GaAs solar cells without a modeling approach to clearly explain it's physics. We have applied the strong SNS modeling approach to shed light on Fermi Level Pinning theory. The modeling confirms that change in position of Fermi Level and it's pining in a lower level close to Valence band increases the recombination and reduces the open-circuit voltage. In contrast, Fermi Level pinning close to conduction band strengthens the electric field at the junction which amplifies the carrier collection and boosts the open-circuit voltage. This theory can well explain the stress effect on device characteristics of various solar cells or Schottky junctions by simply finding the right Fermi level pinning position at every specific stress condition.

  17. Magnetic flux noise in copper oxide superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, M.J.

    1991-11-01

    Magnetic flux noise and flux creep in thin films and single crystals of YBa{sub 2}Cu{sub 3}O{sub 7-x}, Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+x}, Tl{sub 2}Ca{sub 2}Ba{sub 2}Cu{sub 3}O{sub x}, and TlCa{sub 2}Ba{sub 2}Cu{sub 3}O{sub x} are measured with a superconducting quantum interference device (SQUID). The noise power spectrum generally scales as 1/f (f is frequency) from 1 Hz to 1 kHz, increases with temperature, and decreases in higher-quality films. It is proportional to the magnetic field B in which the sample is cooled, at least in the range 0.1 mT < B < 3 mT. A model of thermally activated vortex motion is developed which explains the dependence of the noise on frequency, temperature, current, and applied magnetic field. The pinning potential is idealized as an ensemble of double wells, each with a different activation energy separating the two states. From the noise measurements, this model yields the distribution of pinning energies in the samples, the vortex hopping distance, the number density of mobile vortices, and the restoring force on a vortex at a typical pinning site. The distribution of pinning energies in YBa{sub 2}Cu{sub 3}O{sub 7-x} shows a broad peak below 0.1 eV. The small ambient magnetic field, and the detection of noise even in the absence of a driving force, insure that the measured pinning energies are characteristic of isolated vortices near thermal equilibrium. The observed vortex density in fields much less than 0.1 mT is too large to be explained by the ambient field, suggesting a mechanism intrinsic to the sample which produces trapped vortices.

  18. Performance measurements of hybrid PIN diode arrays

    International Nuclear Information System (INIS)

    Jernigan, J.G.; Arens, J.F.; Collins, T.; Herring, J.; Shapiro, S.L.; Wilburn, C.D.

    1990-05-01

    We report on the successful effort to develop hybrid PIN diode arrays and to demonstrate their potential as components of vertex detectors. Hybrid pixel arrays have been fabricated by the Hughes Aircraft Co. by bump bonding readout chips developed by Hughes to an array of PIN diodes manufactured by Micron Semiconductor Inc. These hybrid pixel arrays were constructed in two configurations. One array format having 10 x 64 pixels, each 120 μm square, and the other format having 256 x 256 pixels, each 30 μm square. In both cases, the thickness of the PIN diode layer is 300 μm. Measurements of detector performance show that excellent position resolution can be achieved by interpolation. By determining the centroid of the charge cloud which spreads charge into a number of neighboring pixels, a spatial resolution of a few microns has been attained. The noise has been measured to be about 300 electrons (rms) at room temperature, as expected from KTC and dark current considerations, yielding a signal-to-noise ratio of about 100 for minimum ionizing particles. 4 refs., 13 figs

  19. Time-Integral Correlations of Multiple Variables With the Relativistic-Electron Flux at Geosynchronous Orbit: The Strong Roles of Substorm-Injected Electrons and the Ion Plasma Sheet

    Science.gov (United States)

    Borovsky, Joseph E.

    2017-12-01

    Time-integral correlations are examined between the geosynchronous relativistic electron flux index Fe1.2 and 31 variables of the solar wind and magnetosphere. An "evolutionary algorithm" is used to maximize correlations. Time integrations (into the past) of the variables are found to be superior to time-lagged variables for maximizing correlations with the radiation belt. Physical arguments are given as to why. Dominant correlations are found for the substorm-injected electron flux at geosynchronous orbit and for the pressure of the ion plasma sheet. Different sets of variables are constructed and correlated with Fe1.2: some sets maximize the correlations, and some sets are based on purely solar wind variables. Examining known physical mechanisms that act on the radiation belt, sets of correlations are constructed (1) using magnetospheric variables that control those physical mechanisms and (2) using the solar wind variables that control those magnetospheric variables. Fe1.2-increasing intervals are correlated separately from Fe1.2-decreasing intervals, and the introduction of autoregression into the time-integral correlations is explored. A great impediment to discerning physical cause and effect from the correlations is the fact that all solar wind variables are intercorrelated and carry much of the same information about the time sequence of the solar wind that drives the time sequence of the magnetosphere.

  20. Friction at high sliding speed of WC-6Co pin versus steel disc AISI 1045: estimation of the contact temperature

    Directory of Open Access Journals (Sweden)

    T Kagnaya

    2016-04-01

    Full Text Available Cemented carbide based cutting tools remain widely used in machiningprocesses for their wear resistance. Knowledge and modelling of wearprocesses are of prior importance to get models to predict and increasethe cutting tool service life. The present paper deals with some results of aresearch work that study relationships between wear and temperature inthe case of pin-on-disc tribological experiments. Topic of the paper isfocussed on the estimation of the pin/disc contact temperature bycoupling experimental measurements and computational methods.Friction experiments are conducted with WC-6Co pins against steeldiscs made of an AISI 1045 grade. Furthermore, WC-6Co pins areinstrumented with two type-K thermocouples. A large sliding velocity rangeis considered in the study: from 100m/min up to 600m/min. The presentpaper is focussed on the 600m/min velocity. During these tribological tests,tangential forces and thermocouple temperatures are measured andmonitored. From these values, the heat flux in the WC-6Co pin is estimatedby two different ways. On one hand by considering the unidirectionalFourier law, on the other hand by estimating the heat partition coefficient [1]between the disc and the pin. The heat partition coefficient is determinedfrom a physical approach based on the consideration of the mechanicalpower dissipated in the contact. In both cases, the heat transfer in the pinis then modelled by finite element methods. It is necessary to performnumerical analysis to estimate the pin/disc interface temperature becauseof the impossibility to measure it directly during friction tests. Results ofexperiments and of numerical simulations are compared.

  1. Transport properties and pinning analysis for Co-doped BaFe2As2 thin films on metal tapes

    Science.gov (United States)

    Xu, Zhongtang; Yuan, Pusheng; Fan, Fan; Chen, Yimin; Ma, Yanwei

    2018-05-01

    We report on the transport properties and pinning analysis of BaFe1.84Co0.16As2 (Ba122:Co) thin films on metal tapes by pulsed laser deposition. The thin films exhibit a large in-plane misorientation of 5.6°, close to that of the buffer layer SrTiO3 (5.9°). Activation energy U 0(H) analysis reveals a power law relationship with field, having three different exponents at different field regions, indicative of variation from single-vortex pinning to a collective flux creep regime. The Ba122:Co coated conductors present {{T}{{c}}}{{onset}} = 20.2 K and {{T}{{c}}}{{zero}} = 19.0 K along with a self-field J c of 1.14 MA cm‑2 and an in-field J c as high as 0.98 and 0.86 MA cm‑2 up to 9 T at 4.2 K for both major crystallographic directions of the applied field, promising for high field applications. Pinning force analysis indicates a significant enhancement compared with similar Ba122:Co coated conductors. By using the anisotropic scaling approach, intrinsic pinning associated with coupling between superconducting blocks can be identified as the pinning source in the vicinity of H//ab, while for H//c random point defects are likely to play a role but correlated defects start to be active at high temperatures.

  2. Neutron scattering from an imperfect flux-line lattice

    International Nuclear Information System (INIS)

    Brandt, E.H.

    1978-01-01

    The diffraction of neutrons from the imperfect vortex lattice of a type-II superconductor is investigated. It is found that flux pinning leads not only to a broadening of the Bragg reflections but also to diffuse scattering into the first Brillouin zone, which at high fields exceeds Bragg scattering

  3. A novel phylogeny and morphological reconstruction of the PIN genes and first phylogeny of the ACC-oxidases (ACOs

    Directory of Open Access Journals (Sweden)

    Ronald Matthew Clouse

    2014-06-01

    Full Text Available The PIN and ACO gene families present interesting questions about the evolution of plant physiology, including testing hypotheses about the ecological drivers of their diversification and whether unrelated genes have been recruited for similar functions. The PIN-formed proteins contribute to the polar transport of auxin, a hormone which regulates plant growth and development. PIN loci are categorized into groups according to their protein length and structure, as well as subcellular localization. An interesting question with PIN genes is the nature of the ancestral form and location. ACOs are members of a superfamily of oxygenases and oxidases that catalyze the last step of ethylene synthesis, which regulates many aspects of the plant life cycle. We used publicly available PIN and ACO sequences to conduct phylogenetic analyses. Third codon positions of these genes in monocots have a high GC content, which could be historical but is more likely due to a mutational bias. Thus we developed methods to extract phylogenetic information from nucleotide sequences while avoiding this convergent feature. One method consisted in using only A-T transformations, and another used only the first and second codon positions for serine, which can only take A or T and G or C, respectively. We also conducted tree-searches for both gene families using unaligned amino acid sequences and dynamic homology. PIN genes appear to have diversified earlier than ACOs, with monocot and dicot copies more mixed in the phylogeny. However, gymnosperm PINs appear to be derived and not closely related to those from primitive plants. We find strong support for a long PIN gene ancestor with short forms subsequently evolving one or more times. ACO genes appear to have diversified mostly since the dicot-monocot split, as most genes cluster into a small number of monocot and dicot clades when the tree is rooted by genes from mosses. Gymnosperm ACOs were recovered as closely related and

  4. Spatiotemporal dynamics and plastic flow of vortices in superconductors with periodic arrays of pinning sites

    Science.gov (United States)

    Reichhardt, C.; Groth, J.; Olson, C. J.; Field, Stuart B.; Nori, Franco

    1996-12-01

    We present simulations of flux-gradient-driven superconducting rigid vortices interacting with square and triangular arrays of columnar pinning sites in an increasing external magnetic field. These simulations allow us to quantitatively relate spatiotemporal microscopic information of the vortex lattice with typically measured macroscopic quantities, such as the magnetization M(H). The flux lattice does not become completely commensurate with the pinning sites throughout the sample at the magnetization matching peaks, but forms a commensurate lattice in a region close to the edge of the sample. Matching fields related to unstable vortex configurations do not produce peaks in M(H). We observe a variety of evolving complex flux profiles, including flat terraces or plateaus separated by winding current-carrying strings and, near the peaks in M(H), plateaus only in certain regions, which move through the sample as the field increases. Several short videos, illustrating several particular cases of the type of dynamics described here, are available at http://www-personal.engin.umich.edu/~nori.

  5. Spatiotemporal dynamics and plastic flow of vortices in superconductors with periodic arrays of pinning sites

    International Nuclear Information System (INIS)

    Reichhardt, C.; Groth, J.; Olson, C.J.; Field, S.B.; Nori, F.

    1996-01-01

    We present simulations of flux-gradient-driven superconducting rigid vortices interacting with square and triangular arrays of columnar pinning sites in an increasing external magnetic field. These simulations allow us to quantitatively relate spatiotemporal microscopic information of the vortex lattice with typically measured macroscopic quantities, such as the magnetization M(H). The flux lattice does not become completely commensurate with the pinning sites throughout the sample at the magnetization matching peaks, but forms a commensurate lattice in a region close to the edge of the sample. Matching fields related to unstable vortex configurations do not produce peaks in M(H). We observe a variety of evolving complex flux profiles, including flat terraces or plateaus separated by winding current-carrying strings and, near the peaks in M(H), plateaus only in certain regions, which move through the sample as the field increases. Several short videos, illustrating several particular cases of the type of dynamics described here, are available at http://www-personal.engin.umich.edu/--nori. copyright 1996 The American Physical Society

  6. Moving vortex phases, dynamical symmetry breaking, and jamming for vortices in honeycomb pinning arrays

    Energy Technology Data Exchange (ETDEWEB)

    Reichhardt, Charles [Los Alamos National Laboratory; Reichhardt, Cynthia [Los Alamos National Laboratory

    2008-01-01

    We show using numerical simulations that vortices in honeycomb pinning arrays can exhibit a remarkable variety of dynamical phases that are distinct from those found for triangular and square pinning arrays. In the honeycomb arrays, it is possible for the interstitial vortices to form dimer or higher n-mer states which have an additional orientational degree of freedom that can lead to the formation of vortex molecular crystals. For filling fractions where dimer states appear, a dynamical symmetry breaking can occur when the dimers flow in one of two possible alignment directions. This leads to transport in the direction transverse to the applied drive. We show that dimerization produces distinct types of moving phases which depend on the direction of the driving force with respect to the pinning lattice symmetry. When the dimers are driven along certain directions, a reorientation of the dimers can produce a jamming phenomenon which results in a strong enhancement in the critical depinning force. The jamming can also cause unusual effects such as an increase in the critical depinning force when the size of the pinning sites is reduced.

  7. Analysis of three idealized reactor configurations: plate, pin, and homogeneous

    International Nuclear Information System (INIS)

    McKnight, R.D.

    1983-01-01

    Detailed Monte Carlo calculations have been performed for three distinct configurations of an idealized fast critical assembly. This idealized assembly was based on the LMFBR benchmark critical assembly ZPR-6/7. In the first configuration, the entire core was loaded with the plate unit cell of ZPR-6/7. In the second configuration, the entire core was loaded with the ZPR sodium-filled pin calandria. The actual ZPR pin calandria are loaded with mixed (U,Pu) oxide pins which closely match the composition of the ZPR-6/7 plate unit cell. For the present study, slight adjustments were made in the atom concentrations and the length of the pin calandria in order to make the core boundaries and average composition for the pin-cell configuration identical to those of the plate-cell configuration. In the third configuration, the core was homogeneous, again with identical core boundaries and average composition as the plate and pin configurations

  8. AFG-MONSU. A program for calculating axial heterogeneities in cylindrical pin cells

    International Nuclear Information System (INIS)

    Neltrup, H.; Kirkegaard, P.

    1978-08-01

    The AGF-MONSU program complex is designed to calculate the flux in cylindrical fuel pin cells into which heterogeneities are introduced in a regular array. The theory - integral transport theory combined with Monte Carlo by help of a superposition principle - is described in some detail. Detailed derivation of the superposition principle as well as the formulas used in the DIT (Discrete Integral Transport) method is given in the appendices along with a description of the input structure of the AFG-MONSU program complex. (author)

  9. Experimental Research on heat transfer enhancement of lubricating-oil cooler with mixing integral pin-fin tubes and plain tubes

    International Nuclear Information System (INIS)

    Niu Guanglin; Yan Changqi; Sun Zhongning; Shi Shuai; Wang Lei

    2010-01-01

    A lot of comparison experimental research has been done to the lubricating-oil cooler with mixing integral pin-fin tubes and plain tubes. It is discovered that the mixing integral pin-fin tubes heat transfer capacity in unit volume is higher, pressure drop is lower, and the very strong heat transfer ability than plain tubes when oil volume flow rate is at constant value. The results show the performance of lubricating-oil cooler with mixing integral pin-fin tubes and plain tubes is superiority. So this can made lubricating-oil cooler miniaturize in the same Heat changing condition. (authors)

  10. Machine optimization in construction of pin blocks

    International Nuclear Information System (INIS)

    Vlasov, G.A.; Zimin, A.M.

    2000-01-01

    The possibility for design of the parts by machine optimization method involves the advent of program products, such as NASTRAN, NIZA, ANSYS and others. The machine optimization is carried out not for partial detail with conforming boundary conditions but a pin block in the assembly in terms of as strengthening, so its dynamic loading. The brief report of optimization using in the ANSYS program is demonstrated. The application of the machine optimization makes it possible to decrease the equivalent static stress to 7 % and load stress to 19 % as compared with original construction [ru

  11. Multi-megawatt pin core space reactor

    International Nuclear Information System (INIS)

    Hornung, R.J.; Normand, E.; Stevens, A.; Teare, K.R.

    1989-01-01

    Boeing has assembled an experienced team to perform a concept definition study of a multi-megawatt (MMW) nuclear power system designed to provide burst power for a space based platform. The design uses the hydrogen needed for platform cooling as the working fluid in an open thermodynamic cycle. The hydrogen is heated by a pin-fuel, fast spectrum reactor and generates power through a pair of counter-rotating turbines which drive four wound rotor alternators. This paper gives an overview of the system, concentrating on features of the reactor design and operation

  12. Analytic models for fuel pin transient performance

    International Nuclear Information System (INIS)

    Bard, F.E.; Fox, G.L.; Washburn, D.F.; Hanson, J.E.

    1976-09-01

    HEDL's ability to analyze various mechanisms that operate within a fuel pin has progressed substantially through development of codes such as PECTCLAD, which solves cladding response, and DSTRESS, which solves fuel response. The PECTCLAD results show good correlation with a variety of mechanical tests on cladding material and also demonstrate the significance of cladding strength when applying the life fraction rule. The DSTRESS results have shown that fuel deforms sufficiently during overpower transient tests that available volumes are filled, whether in the form of a central cavity or start-up cracks

  13. Optimum Prestress of Tanks with Pinned Base

    DEFF Research Database (Denmark)

    Brøndum-Nielsen, Troels

    1998-01-01

    Amin Ghali and Eleanor Elliott presented in their paper an interesting suggestion for prestressing of circular tanks without sliding joints. For many prestressed tanks the following construction procedure is adopted:In order to ensure compressive hoop forces in the wall near the base, the wall...... is allowed to slide freely in the radial direction during tensioning (free base).After tensioning such displacements are prevented (pinned base). The present paper addresses the problem of prestress of such tanks.Keywords: circular prestressing; creep properties; prestressed concrete; redistribution...

  14. Sodium erosion of boron carbide from breached absorber pins

    International Nuclear Information System (INIS)

    Basmajian, J.A.; Baker, D.E.

    1981-03-01

    The purpose of the irradiation experiment was to provide an engineering demonstration of the irradiation behavior of breached boron carbide absorber pins. By building defects into the cladding of prototypic absorber pins, and performing the irradiation under typical FFTF operating conditions, a qualitative assessment of the consequences of a breach was achieved. Additionally, a direct comparison of pin behavior with that of the ex-reactor test could be made

  15. Heat transfer in a fuel pin shipping container

    International Nuclear Information System (INIS)

    Ingham, J.G.

    1980-01-01

    Maximum cladding temperatures occur when the IDENT 1578 fuel pin shipping container is installed in the T-3 Cask. The maximum allowable cladding temperature of 800 0 F is reached when the rate of energy deposited in the 19-pin basket reaches 400 watts. Since 45% of the energy which is generated in the fuel escapes the 19-pin basket without being deposited, mostly gamma energy, the maximum allowable rate of heat generation is 400/.55 = 727 watts. Similarly, the maximum allowable cladding temperature of 800 0 F is reached when the rate of energy deposited in the 40-pin basket reaches 465 watts. Since 33% of the energy which is generated in the fuel escapes the 40-pin basket without being deposited, mostly gamma energy, the maximum allowable rate of heat generation is 465/.66 = 704 watts. The IDENT 1578 fuel pin shipping container therefore meets its thermal design criteria. IDENT 1578 can handle fuel pins with a decay heat load of 600 watts while maintaining the maximum fuel pin cladding temperature below 800 0 F. The emissivities which were determined from the test results for the basket tubes and container are relatively low and correspond to new, shiny conditions. As the IDENT 1578 container is exposed to high temperatures for extended periods of time during the transportation of fuel pins, the emissivities will probably increase. This will result in reduced temperatures

  16. Nano-engineered pinning centres in YBCO superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Crisan, A., E-mail: adrian.crisan@infim.ro [National Institute for Materials Physics Bucharest, 105 bis Atomistilor Str., 077125 Magurele (Romania); School of Metallurgy and Materials, University of Birmingham, Edgbaston, B15 2TT Birmingham (United Kingdom); Dang, V.S. [School of Metallurgy and Materials, University of Birmingham, Edgbaston, B15 2TT Birmingham (United Kingdom); Nano and Energy Center, VNU Hanoi University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi (Viet Nam); Mikheenko, P. [School of Metallurgy and Materials, University of Birmingham, Edgbaston, B15 2TT Birmingham (United Kingdom); Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway)

    2017-02-15

    Highlights: • Power applications of YBCO films/coated conductors in technological relevant magnetic fields requires nano-engineered pinning centre. • Three approaches have been proposed: substrate decoration, quasi-multilayers, and targets with secondary phase nano-inclusions. • Combination of all three approaches greatly increased critical current in YBCO films. • Bulk pinning force, pinning potential, and critical current density are estimated and discussed in relation with the type and strength of pinning centres related to the defects evidenced by Transmission Electron Microscopy. - Abstract: For practical applications of superconducting materials in applied magnetic fields, artificial pinning centres in addition to natural ones are required to oppose the Lorentz force. These pinning centres are actually various types of defects in the superconductor matrix. The pinning centres can be categorised on their dimension (volume, surface or point) and on their character (normal cores or Δκ cores). Different samples have been produced by Pulsed Laser Deposition, with various thicknesses, temperatures and nanostructured additions to the superconducting matrix. They have been characterized by SQUID Magnetic Properties Measurement System and Physical Properties Measurement System, as well as by Transmission Electron Microscopy (TEM). Correlations between pinning architecture, TEM images, and critical currents at various fields and field orientations will be shown for a large number of YBa{sub 2}Cu{sub 3}O{sub x} films with various types and architectures of artificial pinning centres.

  17. Study of the Radiation Hardness of VCSEL and PIN Arrays

    CERN Document Server

    Gan, K.K.; Kagan, H.P.; Kass, R.D.; Law, A.; Rau, A.; Smith, D.S.; Lebbai, M.R.M.; Skubic, P.L.; Abi, B.; Rizardinova, F.

    2008-01-01

    The silicon trackers of the ATLAS experiment at LHC (CERN) use optical links for data transmission. VCSEL arrays operating at 850 nm are used to transmit optical signals while PIN arrays are used to convert the optical signals into electrical signals. We investigate the feasibility of using the devices at the Super LHC (SLHC). We irradiated VCSEL and GaAs PIN arrays from three vendors and silicon PIN arrays from one vendor. All arrays can be operated up to the SLHC dosage except the GaAs PIN arrays which have very low responsivities after irradiation and hence are probably not suitable for the SLHC application.

  18. Dynamic Phases of Vortices in Superconductors with Periodic Pinning

    International Nuclear Information System (INIS)

    Reichhardt, C.; Olson, C.; Nori, F.

    1997-01-01

    We present results from extensive simulations of driven vortex lattices interacting with periodic arrays of pinning sites. Changing an applied driving force produces a rich variety of novel dynamical plastic flow phases which are very distinct from those observed in systems with random pinning arrays. Signatures of the transition between these different dynamical phases include sudden jumps in the current-voltage curves as well as marked changes in the vortex trajectories and vortex lattice order. Several dynamical phase diagrams are obtained as a function of commensurability, pinning strength, and spatial order of the pinning sites. copyright 1997 The American Physical Society

  19. Strong Relationship between Irreversibility Field and Crystallinity Discovered in Undoped and Carbon Substituted MgB2 Bulks

    International Nuclear Information System (INIS)

    Yamamoto, Akiyasu; Shimoyama, Jun-ichi; Ueda, Shinya; Iwayama, Isao; Katsura, Yukari; Horii, Shigeru; Kishio, Kohji

    2006-01-01

    The relationship between irreversibility field, H irr , and crystallinity of MgB 2 bulks including SiC or B 4 C doped samples was studied. Among the XRD peaks of MgB 2 , the FWHM of (110) reflection corresponding to the in-plane disorder was strongly dependent on the samples and H irr was found to be systematically increased with an increase of the FWHM of MgB 2 (110) peak. Enhanced intra-band scattering and strengthened grain boundary flux pinning are suggested to contribute to the excellent H irr characteristics. On the other hand, weak correlation between H irr and FWHM of (002) peak was confirmed. These mean that introduction of disorders into the ab-plane, i.e., distortion in honeycomb boron sheet, is essentially effective to enhance H irr

  20. FABRICE process for the refrabrication of experimental pins in a hot cell, from pins pre-irradiated in power reactors

    International Nuclear Information System (INIS)

    Vignesoult, N.; Atabek, R.; Ducas, S.

    1982-06-01

    The Fabrice ''hot cell refabrication'' process for small pins from very long irradiated fuel elements was developed at the CEA to allow parametric studies of the irradiation behavior of pins from nuclear power plants. Since this operation required complete assurance of the validity of the process, qualification of the fabrication was performed on test pins, refabricated in the hot cell, as well as irradiation qualification. The latter qualification was intended to demonstrate that, in identical experimental irradiation conditions, the refabricated Fabrice pins behaved in the same way as whole pins with the same initial characteristics. This qualification of the Fabrice process, dealing with more than twenty pins at different burnups, showed that fabrication did not alter: the inherent characteristics of the sampled fuel element and the irradiation behavior of the sampled fuel element [fr

  1. Pin-ups: pictures that fascinate and seduce Pin-ups: fotografias que encantam e seduzem

    Directory of Open Access Journals (Sweden)

    Maria Irene Pellegrino de Oliveira Souza

    2010-08-01

    Full Text Available Starting from photography studies, social anthropology and body visual, this article approaches the social construction of the feminine image through times. It narrates the history of erotic pinups photography and its fetishist elements. Pin-ups have aroused in the end of 19tcentury and it represents the free spirit of women. Slowly, it provokes the breakup of sensuality and sexuality feminine traditionalism. The article also discusses women’s sensuality as a desire object. The pin-ups sensual demure – with a mystery atmosphere – stimulated the eroticism at the beginning of the 20 century and, until nowadays, it provokes admiration, sigh and desire. Com base em estudos sobre fotografia, antropologia social e visual do corpo, este artigo aborda a imagem feminina socialmente construída através dos tempos. Narra o histórico da fotografia erótica de pin-ups e seus elementos fetichistas. As pin-ups surgiram no final do século XIX e representaram o espírito “livre” das mulheres. Sutilmente, incitavam o rompimento do tradicionalismo da época quanto à sensualidade e sexualidade feminina. O artigo aborda também a sensualidade feminina como objeto de desejo. O recato sensual das pin-ups – com ar de mistério – alavancou o erotismo no início do século XX e, até os dias atuais, provoca admiração, suspiros e desejos.

  2. The Egyptian Hair Pin: practical, sacred, fatal

    Directory of Open Access Journals (Sweden)

    Joann Fletcher

    2016-11-01

    Full Text Available Generally regarded as little more than a mundane tool employed in daily life, the humble hairpin occasionally played a rather more prominent role in history than has perhaps been appreciated. As the most ancient implements associated with hair styling, simple pins of bone and ivory were commonly employed in Egypt by c.4000 BC as a means of securing long hair in an upswept style (e.g. Petrie and Mace 1901, 21, 34. Although their occasional use by men undermines the assumption that hairpins are 'a relatively certain example of a “gendered” artefact' (Wilfong 1997, 67, the vast majority have been found in female burials. They can be made of bone and ivory, wood, steatite, glass, gold, silver and bronze, and two 12cm long bronze examples were found within the hair of Princess Ahmosi c.1550 BC (Fletcher 1995, 376, 441 while the hair of an anonymous woman at Gurob c.AD 110 had been secured in a bun with pins of bone, tortoiseshell and silver (Walker and Bierbrier 1997, 209.

  3. BARS - a heterogeneous code for 3D pin-by-pin LWR steady-state and transient calculation

    International Nuclear Information System (INIS)

    Avvakumov, A.V.; Malofeev, V.M.

    2000-01-01

    A 3D pin-by-pin dynamic model for LWR detailed calculation was developed. The model is based on a coupling of the BARS neutronic code with the RELAP5/MOD3.2 thermal hydraulic code. This model is intended to calculate a fuel cycle, a xenon transient, and a wide range of reactivity initiated accidents in a WWER and a PWR. Galanin-Feinberg heterogeneous method was realized in the BARS code. Some results for a validation of the heterogeneous method are presented for reactivity coefficients, a pin-by-pin power distribution, and a fast pulse transient. (Authors)

  4. Experimental study on the effect of heat flux tilt on rod bundle dryout limitation

    International Nuclear Information System (INIS)

    Sugawara, S.; Terunuma, K.; Kamoshida, H.

    1995-01-01

    The effect of heat flux tilt on rod bundle dryout limitation was studied experimentally using a full-scale mock-up test facility and simulated 36-rod fuel bundles in which heater pins have azimuthal nonuniform heat flux distribution (i.e., heat flux tilt). Experimental results for typical lateral power distribution in the bundle indicate that the bundle dryout power with azimuthal heat flux tilt is higher than that without azimuthal heat flux tilt in the entire experimental range. Consequently, it is concluded that the dryout experiment using the test bundle with heater pins which has circumferentially uniform heat flux distribution gives conservative results for the usual lateral power distribution in a bundle in which the relative power of outermost-circle fuel rods is higher than those of middle- and inner-circle ones. (author). 15 refs., 2 tabs., 8 figs

  5. Characterization of high flux magnetized helium plasma in SCU-PSI linear device

    Science.gov (United States)

    Xiaochun, MA; Xiaogang, CAO; Lei, HAN; Zhiyan, ZHANG; Jianjun, WEI; Fujun, GOU

    2018-02-01

    A high-flux linear plasma device in Sichuan University plasma-surface interaction (SCU-PSI) based on a cascaded arc source has been established to simulate the interactions between helium and hydrogen plasma with the plasma-facing components in fusion reactors. In this paper, the helium plasma has been characterized by a double-pin Langmuir probe. The results show that the stable helium plasma beam with a diameter of 26 mm was constrained very well at a magnetic field strength of 0.3 T. The core density and ion flux of helium plasma have a strong dependence on the applied current, magnetic field strength and gas flow rate. It could reach an electron density of 1.2 × 1019 m‑3 and helium ion flux of 3.2 × 1022 m‑2 s‑1, with a gas flow rate of 4 standard liter per minute, magnetic field strength of 0.2 T and input power of 11 kW. With the addition of ‑80 V applied to the target to increase the helium ion energy and the exposure time of 2 h, the flat top temperature reached about 530 °C. The different sizes of nanostructured fuzz on irradiated tungsten and molybdenum samples surfaces under the bombardment of helium ions were observed by scanning electron microscopy. These results measured in the SCU-PSI linear device provide a reference for International Thermonuclear Experimental Reactor related PSI research.

  6. Optical fuel pin scanner. [Patent application; for reading identifications

    Science.gov (United States)

    Kirchner, T.L.; Powers, H.G.

    1980-12-09

    This patent relates to an optical identification system developed for post-irradiation disassembly and analysis of fuel bundle assemblies. The apparatus is designed to be lowered onto a stationary fuel pin to read identification numbers or letters imprinted on the circumference of the top fuel pin and cap. (DLC)

  7. Percutaneous pin fixation of Gartland Type III supraconylar fractures ...

    African Journals Online (AJOL)

    The remaining three (7.5%) had poor results due to varus deformity that neededcorrective surgery. One case of pin tract infection was recorded. The average hospital stay was 1.2 days. The study confirmed that percutaneous pin fixation is an effective, minimally invasive and safe method of fixation of these difficult fractures ...

  8. Pinning Stabilizes Neighboring Surface Nanobubbles against Ostwald Ripening

    NARCIS (Netherlands)

    Dollet, B.; Lohse, Detlef

    2016-01-01

    Pinning of the contact line and gas oversaturation explain the stability of single surface nanobubbles. In this article, we theoretically show that the pinning also suppresses the Ostwald ripening process between neighboring surface nanobubbles, thus explaining why in a population of neighboring

  9. 21 CFR 872.3740 - Retentive and splinting pin.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3740 Retentive and splinting pin. (a) Identification. A retentive and splinting pin is a device made of austenitic alloys or alloys containing 75 percent or greater gold and metals of the platinum group intended to be placed permanently in a tooth to...

  10. In vitro analysis of self-shearing retentive pins.

    Science.gov (United States)

    Collard, E W; Caputo, A A; Standlee, J P; Duncanson, M G

    1981-02-01

    Combining stress, analysis, microscopic examination, mechanical testing of the shear mechanism, and retention of the Reten Pin leads to the following conclusions: 1. The suggested 0.006 inch pin-channel mismatch induces high lateral and apical stresses. Microscopically, this was seen to correlate with injury to the dentin. 2. The degree of retention was increased by using a smaller pin-channel mismatch. This correlates with smaller stresses and reduced dentinal damage. 3. The shear mechanism acts in a uniform manner, with a relatively small variation from the mean. It is suggested that for the best results the manufacturer should supply larger twist drills and pins with a somewhat deeper self-shearing groove to minimize apical involvement during shearing of the handle from the pin.

  11. Retrievable fuel pin end member for a nuclear reactor

    International Nuclear Information System (INIS)

    Rosa, J.M.

    1982-01-01

    A bottom end member on a retrievable fuel pin secures the pin within a nuclear reactor by engaging on a transverse attachment rail with a spring clip type of action. Removal and reinstallation if facilitated as only axial movement of the fuel pin is required for either operation. A pair of resilient axially extending blades are spaced apart to define a slot having a seat region which receives the rail and having a land region, closer to the tips of the blades which is normally of less width than the rail. Thus an axially directed force sufficient to wedge the resilient blades apart is required to emplace or release the fuel pin such force being greater than the axial forces on the fuel pins which occur during operation of the reactor

  12. Verification of the CASMO-3/SIMULATE-3 pin power accuracy by comparison with operating boiling water reactor measurements

    International Nuclear Information System (INIS)

    Uegata, T.; Saji, E.; Tanaka, H.

    1993-01-01

    Intranodal pin power distributions calculated by the CASMO-3/SIMULATE-3 code have been compared with pin gamma scan measurements. These data were obtained from the depleted core of an operating boiling water reactor (BWR), which is more complicated than a pressurized water reactor to calculate because of the existence of coolant void distributions and cruciform control blades. Furthermore, measured bundles include mixed-oxide (MOX) bundles in which steep thermal flux gradients occur. Both UO 2 and MOX bundles have been calculated in the same manner based on the standard CASMO-3/SIMULATE-3 methods. The total pin power root-mean-square (rms) error is 2.7%, which includes measurement error, from an 896-point comparison. There is no obvious dependency on axial elevations (void fractions) and no significant difference between fuel types (UO 2 or MOX), although the errors in a peripheral bundle, which is less important from the standpoint of core design, are somewhat larger than those in the internal bundles. If the peripheral bundle is excluded, the total rms error is reduced to 2.2%. From these results, it is concluded that excellent agreement has been obtained between the calculations and measurements and that the calculational capability of CASMO-3/SIMULATE-3 for the intranodal pin power distribution is quite satisfactory and useful for BWR core design

  13. A pinning puzzle: two similar, non-superconducting chemical deposits in YBCO-one pins, the other does not

    Energy Technology Data Exchange (ETDEWEB)

    Sawh, Ravi-Persad; Weinstein, Roy; Gandini, Alberto; Skorpenske, Harley; Parks, Drew, E-mail: Weinstein@uh.ed [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Department of Physics, University of Houston, Houston, TX 77204-5005 (United States); Texas Center for Superconductivity at UH, University of Houston, Houston, TX 77204-5002 (United States)

    2009-09-15

    The pinning effects of two kinds of U-rich deposits in YBCO (YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}) are compared. One is a five-element compound, (U{sub 0.6}Pt{sub 0.4})YBa{sub 2}O{sub 6}, which is a paramagnetic double perovskite which forms as profuse stable nanosize deposits, and pins very well. The other is a four-element compound, (U{sub 0.4}Y{sub 0.6})BaO{sub 3}, which is a ferromagnetic single perovskite which forms as profuse stable nanosize deposits and pins very weakly or not at all. The pinning comparison is done with nearly equal deposit sizes and number of deposits per unit volume for the two compounds. Evidence for the pinning capability, chemical makeup, x-ray diffraction signature, and magnetic properties of the two compounds is reported.

  14. Critical flux determination by flux-stepping

    DEFF Research Database (Denmark)

    Beier, Søren; Jonsson, Gunnar Eigil

    2010-01-01

    In membrane filtration related scientific literature, often step-by-step determined critical fluxes are reported. Using a dynamic microfiltration device, it is shown that critical fluxes determined from two different flux-stepping methods are dependent upon operational parameters such as step......, such values are more or less useless in itself as critical flux predictors, and constant flux verification experiments have to be conducted to check if the determined critical fluxes call predict sustainable flux regimes. However, it is shown that using the step-by-step predicted critical fluxes as start...

  15. Roles of pinning strength and density in vortex melting

    International Nuclear Information System (INIS)

    Obaidat, I M; Khawaja, U Al; Benkraouda, M

    2008-01-01

    We have investigated the role of pinning strength and density on the equilibrium vortex-lattice to vortex-liquid phase transition under several applied magnetic fields. This study was conducted using a series of molecular dynamic simulations on several samples with different strengths and densities of pinning sites which are arranged in periodic square arrays. We have found a single solid-liquid vortex transition when the vortex filling factor n>1. We have found that, for fixed pinning densities and strengths, the melting temperature, T m , decreases almost linearly with increasing magnetic field. Our results provide direct numerical evidence for the significant role of both the strength and density of pinning centers on the position of the melting line. We have found that the vortex-lattice to vortex-liquid melting line shifts up as the pinning strength or the pinning density was increased. The effect on the melting line was found to be more pronounced at small values of strength and density of pinning sites

  16. Loss of Pin1 Suppresses Hedgehog-Driven Medulloblastoma Tumorigenesis

    Directory of Open Access Journals (Sweden)

    Tao Xu

    2017-03-01

    Full Text Available Medulloblastoma is the most common malignant brain tumor in children. Therapeutic approaches to medulloblastoma (combination of surgery, radiotherapy, and chemotherapy have led to significant improvements, but these are achieved at a high cost to quality of life. Alternative therapeutic approaches are needed. Genetic mutations leading to the activation of the Hedgehog pathway drive tumorigenesis in ~30% of medulloblastoma. In a yeast two-hybrid proteomic screen, we discovered a novel interaction between GLI1, a key transcription factor for the mediation of Hedgehog signals, and PIN1, a peptidylprolyl cis/trans isomerase that regulates the postphosphorylation fate of its targets. The GLI1/PIN1 interaction was validated by reciprocal pulldowns using epitope-tagged proteins in HEK293T cells as well as by co-immunoprecipiations of the endogenous proteins in a medulloblastoma cell line. Our results support a molecular model in which PIN1 promotes GLI1 protein abundance, thus contributing to the positive regulation of Hedgehog signals. Most importantly, in vivo functional analyses of Pin1 in the GFAP-tTA;TRE-SmoA1 mouse model of Hedgehog-driven medulloblastoma demonstrate that the loss of Pin1 impairs tumor development and dramatically increases survival. In summary, the discovery of the GLI1/PIN1 interaction uncovers PIN1 as a novel therapeutic target in Hedgehog-driven medulloblastoma tumorigenesis.

  17. Flux trapping and shielding in irreversible superconductors

    International Nuclear Information System (INIS)

    Frankel, D.J.

    1978-05-01

    Flux trappings and shielding experiments were carried out on Pb, Nb, Pb-Bi, Nb-Sn, and Nb-Ti samples of various shapes. Movable Hall probes were used to measure fields near or inside the samples as a function of position and of applied field. The trapping of transverse multipole magnetic fields in tubular samples was accomplished by cooling the samples in an applied field and then smoothly reducing the applied field to zero. Transverse quadrupole and sextupole fields with gradients of over 2000 G/cm were trapped with typical fidelity to the original impressed field of a few percent. Transverse dipole fields of up to 17 kG were also trapped with similar fidelity. Shielding experiments were carried out by cooling the samples in zero field and then gradually applying an external field. Flux trapping and shielding abilities were found to be limited by two factors, the pinning strength of the material, and the susceptibility of a sample to flux jumping. The trapping and shielding behavior of flat disk samples in axial fields and thin-walled tubular samples in transverse fields was modeled. The models, which were based on the concept of the critical state, allowed a connection to be made between the pinning strength and critical current level, and the flux trapping and shielding abilities. Adiabatic and dynamic stability theories are discussed and applied to the materials tested. Good qualitative, but limited quantitative agreement was obtained between the predictions of the theoretical stability criteria and the observed flux jumping behavior

  18. Discovery of novel selenium derivatives as Pin1 inhibitors by high-throughput screening

    Energy Technology Data Exchange (ETDEWEB)

    Subedi, Amit [Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science, Wako, Saitama, 351-0198 (Japan); Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570 (Japan); Shimizu, Takeshi [Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science, Wako, Saitama, 351-0198 (Japan); Ryo, Akihide [Department of Microbiology, Yokohama City University School of Medicine, Yokohama, Kanagawa, 236-0004 (Japan); Sanada, Emiko [Bio-Active Compounds Discovery Unit, RIKEN Center for Sustainable Resource Science, Wako, Saitama, 351-0198 (Japan); Watanabe, Nobumoto [Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science, Wako, Saitama, 351-0198 (Japan); Bio-Active Compounds Discovery Unit, RIKEN Center for Sustainable Resource Science, Wako, Saitama, 351-0198 (Japan); Osada, Hiroyuki, E-mail: hisyo@riken.jp [Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science, Wako, Saitama, 351-0198 (Japan); Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570 (Japan)

    2016-06-03

    Peptidyl prolyl cis/trans isomerization by Pin1 regulates various oncogenic signals during cancer progression, and its inhibition through multiple approaches has established Pin1 as a therapeutic target. However, lack of simplified screening systems has limited the discovery of potent Pin1 inhibitors. We utilized phosphorylation-dependent binding of Pin1 to its specific substrate to develop a screening system for Pin1 inhibitors. Using this system, we screened a chemical library, and identified a novel selenium derivative as Pin1 inhibitor. Based on structure-activity guided chemical synthesis, we developed more potent Pin1 inhibitors that inhibited cancer cell proliferation. -- Highlights: •Novel screening for Pin1 inhibitors based on Pin1 binding is developed. •A novel selenium compound is discovered as Pin1 inhibitor. •Activity guided chemical synthesis of selenium derivatives resulted potent Pin1 inhibitors.

  19. Inverse crystallization if Abrikosov vortex system at periodic pinning

    CERN Document Server

    Zyubin, M V; Kashurnikov, V A

    2002-01-01

    The vortex system in the quasi-two-dimensional HTSC plate is considered in the case of the periodic pinning. The M(H) magnetization curves by various values of the external magnetic field and different temperatures are calculated through the Monte Carlo method. It is shown that in the case of the periodic pinning the crystallization of the vortex system is possible by the temperature increase. A number of peculiarities conditioned by the impact of the pinning centers periodic lattice are identified on the magnetization curves. The pictures of the vortex distribution corresponding to various points on the M(H) curve are obtained

  20. Cladding dimensional changes in mixed oxide fuel pins

    International Nuclear Information System (INIS)

    Makenas, B.J.; Jost, J.W.; Hales, J.W.

    1980-01-01

    Several types of stainless steel (304, 316, 316-20% Cold Worked, and 316 Titanium stabilized 20% CW) have been used as cladding for mixed oxide (U, Pu)O 2 fuel pins irradiated in EBR-II. All of the materials have performed satisfactorily in their respective experimental subassemblies but significant differences in swelling and inelastic strain behavior have been found at high fast fluences among the different materials and among different heats of the same material. Cladding diameter increases were measured for 622 developmental and FFTF reference design fuel pins which were irradiated in 19 experimental subassemblies. Fuel pin diameters were determined from multiangle axial trace profilometry measurements

  1. Fabrication of oxide dispersion strengthened ferritic clad fuel pins

    International Nuclear Information System (INIS)

    Zirker, L.R.; Bottcher, J.H.; Shikakura, S.; Tsai, C.L.

    1991-01-01

    A resistance butt welding procedure was developed and qualified for joining ferritic fuel pin cladding to end caps. The cladding are INCO MA957 and PNC ODS lots 63DSA and 1DK1, ferritic stainless steels strengthened by oxide dispersion, while the end caps are HT9 a martensitic stainless steel. With adequate parameter control the weld is formed without a residual melt phase and its strength approaches that of the cladding. This welding process required a new design for fuel pin end cap and weld joint. Summaries of the development, characterization, and fabrication processes are given for these fuel pins. 13 refs., 6 figs., 1 tab

  2. Fuel pin design algorithm for conceptual design studies

    International Nuclear Information System (INIS)

    Uselman, J.P.

    1979-01-01

    Two models are available which are currently verified by part of the requirements and which are adaptable as algorithms for the complete range. Fuel thermal performance is described by the HEDL SIEX model. Cladding damage and total deformation are determined by the GE GRO-II structural analysis code. A preliminary fuel pin performance model for analysis of (U, P/sub U/)O 2 pins in the COROPT core conceptual design system has been constructed by combining the key elements of SIEX and GRO-II. This memo describes the resulting pin performance model and its interfacing with COROPT system. Some exemplary results are presented

  3. Inventory Assessment of Pin-wise Isotopic Composition in the Spent Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Zafar, Zafar Iqbal; Kim, Myung Hyun [Kyung Hee University, Yongin (Korea, Republic of)

    2016-05-15

    There is no direct method to determine the pin-wise composition in a reasonable time frame, so, different multifaceted attempts have been made to calculate isotopic distribution of the SNF under special circumstances. There are numerous factors that influence the final SNF composition; initial fuel composition (especially enrichment), operating conditions of the reactor and final burnup imparted to the fuel, to name a few. An assumption, usually employed implicitly, is that the SNF composition is a function of the burnup and the initial enrichment only. Current methodology can be utilized by making use of the three code strategy i.e. (HELIOS 1.5, MASTER 2.2, and ORIGEN2) to assess the amount of the isotopes that are hazardous for being radioactive as well as those ones that have some role (positive or negative) in reactivity variations inside the core. Effect of the operating power i.e. dominant neutron flux is also incorporated. The minor spectrum variation from BOC to the EOC could be neglected because PWR assemblies are adorned in a way to make the neutron spectrum uniform over the core; (2) minor variation of the neutron spectrum has very little effect on the SNF composition. Few isotopes like Cs-135, Pu-241, etc. show remarkable dependence on the reactor operating conditions (e.g. operating power level) while many important isotopes like U-235, I-129, Cs-137, etc. depend on the net burnup imparted to the fuel only. Detailed pin-wise isotopic composition of the spent nuclear fuel from PWRs could be ascertained if influence of all of the concerned parameters is considered precisely. Here, we considered effect of the burnup on the composition of a selected fuel pin from the assembly B-7. Effect of the operating power level (i.e. flux) is accounted implicitly. This technique of composition reconstruction utilizes the pin-wise burnup calculation capability of the core analysis code MASTER 2.2. The relative magnitudes of the considered isotopes from two different

  4. The NuMA-related Mud protein binds Pins and regulates spindle orientation in Drosophila neuroblasts.

    Science.gov (United States)

    Siller, Karsten H; Cabernard, Clemens; Doe, Chris Q

    2006-06-01

    Asymmetric cell division generates cell diversity during development and regulates stem-cell self-renewal in Drosophila and mammals. In Drosophila, neuroblasts align their spindle with a cortical Partner of Inscuteable (Pins)-G alpha i crescent to divide asymmetrically, but the link between cortical polarity and the mitotic spindle is poorly understood. Here, we show that Pins directly binds, and coimmunoprecipitates with, the NuMA-related Mushroom body defect (Mud) protein. Pins recruits Mud to the neuroblast apical cortex, and Mud is also strongly localized to centrosome/spindle poles, in a similar way to NuMA. In mud mutants, cortical polarity is normal, but the metaphase spindle frequently fails to align with the cortical polarity axis. When spindle orientation is orthogonal to cell polarity, symmetric division occurs. We propose that Mud is a functional orthologue of mammalian NuMA and Caenorhabditis elegans Lin-5, and that Mud coordinates spindle orientation with cortical polarity to promote asymmetric cell division.

  5. Superconducting vortex pinning with artificial magnetic nanostructures.

    Energy Technology Data Exchange (ETDEWEB)

    Velez, M.; Martin, J. I.; Villegas, J. E.; Hoffmann, A.; Gonzalez, E. M.; Vicent, J. L.; Schuller, I. K.; Univ. de Oviedo-CINN; Unite Mixte de Physique CNRS/Thales; Univ. Paris-Sud; Univ.Complutense de Madrid; Univ. California at San Diego

    2008-11-01

    This review is dedicated to summarizing the recent research on vortex dynamics and pinning effects in superconducting films with artificial magnetic structures. The fabrication of hybrid superconducting/magnetic systems is presented together with the wide variety of properties that arise from the interaction between the superconducting vortex lattice and the artificial magnetic nanostructures. Specifically, we review the role that the most important parameters in the vortex dynamics of films with regular array of dots play. In particular, we discuss the phenomena that appear when the symmetry of a regular dot array is distorted from regularity towards complete disorder including rectangular, asymmetric, and aperiodic arrays. The interesting phenomena that appear include vortex-lattice reconfigurations, anisotropic dynamics, channeling, and guided motion as well as ratchet effects. The different regimes are summarized in a phase diagram indicating the transitions that take place as the characteristic distances of the array are modified respect to the superconducting coherence length. Future directions are sketched out indicating the vast open area of research in this field.

  6. Ideal glass transitions by random pinning

    Science.gov (United States)

    Cammarota, Chiara; Biroli, Giulio

    2012-01-01

    We study the effect of freezing the positions of a fraction c of particles from an equilibrium configuration of a supercooled liquid at a temperature T. We show that within the random first-order transition theory pinning particles leads to an ideal glass transition for a critical fraction c = cK(T) even for moderate supercooling; e.g., close to the Mode-Coupling transition temperature. First we derive the phase diagram in the T - c plane by mean field approximations. Then, by applying a real-space renormalization group method, we obtain the critical properties for |c - cK(T)| → 0, in particular the divergence of length and time scales, which are dominated by two zero-temperature fixed points. We also show that for c = cK(T) the typical distance between frozen particles is related to the static point-to-set length scale of the unconstrained liquid. We discuss what are the main differences when particles are frozen in other geometries and not from an equilibrium configuration. Finally, we explain why the glass transition induced by freezing particles provides a new and very promising avenue of research to probe the glassy state and ascertain, or disprove, the validity of the theories of the glass transition. PMID:22623524

  7. A PWR Thorium Pin Cell Burnup Benchmark

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Kevan Dean; Zhao, X.; Pilat, E. E; Hejzlar, P.

    2000-05-01

    As part of work to evaluate the potential benefits of using thorium in LWR fuel, a thorium fueled benchmark comparison was made in this study between state-of-the-art codes, MOCUP (MCNP4B + ORIGEN2), and CASMO-4 for burnup calculations. The MOCUP runs were done individually at MIT and INEEL, using the same model but with some differences in techniques and cross section libraries. Eigenvalue and isotope concentrations were compared on a PWR pin cell model up to high burnup. The eigenvalue comparison as a function of burnup is good: the maximum difference is within 2% and the average absolute difference less than 1%. The isotope concentration comparisons are better than a set of MOX fuel benchmarks and comparable to a set of uranium fuel benchmarks reported in the literature. The actinide and fission product data sources used in the MOCUP burnup calculations for a typical thorium fuel are documented. Reasons for code vs code differences are analyzed and discussed.

  8. Application of PIN photodiodes as radiation detectors

    International Nuclear Information System (INIS)

    Canu, B.; Dolleiser, M.; Peak, L.

    2000-01-01

    Full text: PIN photodiode based detectors have been built, tested and are currently in use as radiation monitors in the Belle experiment at KEK, Japan. The photodiode operates in unbiased mode as a current source attached to an operational amplifier (Burr-Brown OPA 129). The detector has been designed to have an almost linear response over a very wide range of radiation dose. To test the efficiency of these unbiased units, we have measured the response of the same detector for varying bias voltages to an input signal of mono-energetic electrons. As a source of these mono-energetic electrons, we have designed and constructed a high luminosity beta spectrometer. The output pulses were collected using a Hewlett-Packard 54522A sampling oscilloscope. They were then analysed and compared with the results of our own simulation code - as well as with EGS4 software. The experiment shows the efficiency of the unbiased detector is as high as ∼75% of the efficiency of the almost fully depleted unit (with bias voltage 54 Volts)

  9. Nodal methods for calculating nuclear reactor transients, control rod patterns, and fuel pin powers

    International Nuclear Information System (INIS)

    Cho, Byungoh.

    1990-01-01

    Nodal methods which are used to calculate reactor transients, control rod patterns, and fuel pin powers are investigated. The 3-D nodal code, STORM, has been modified to perform these calculations. Several numerical examples lead to the following conclusions: (1) By employing a thermal leakage-to-absorption ratio (TLAR) approximation for the spatial shape of the thermal fluxes for the 3-D Langenbuch-Maurer-Werner (LMW) and the superprompt critical transient problems, the convergence of the conventional two-group scheme is accelerated. (2) By employing the steepest-ascent hill climbing search with heuristic strategies, Optimum Control Rod Pattern Searcher (OCRPS) is developed for solving control rod positioning problem in BWRs. Using the method of approximation programming the objective function and the nuclear and thermal-hydraulic constraints are modified as heuristic functions that guide the search. The test calculations have demonstrated that, for the first cycle of the Edwin Hatch Unit number-sign 2 reactor, OCRPS shows excellent performance for finding a series of optimum control rod patterns for six burnup steps during the operating cycle. (3) For the modified two-dimensional EPRI-9R problem, the least square second-order polynomial flux expansion method was demonstrated to be computationally about 30 times faster than a fine-mesh finite difference calculation in order to achieve comparable accuracy for pin powers. The basic assumption of this method is that the reconstructed flux can be expressed as a product of an assembly form function and a second-order polynomial function

  10. Magnetic flux noise in copper oxide superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, Mark Joseph [Univ. of California, Berkeley, CA (United States)

    1991-11-01

    Magnetic flux noise and flux creep in thin films and single crystals of YBa2Cu3O7-x, Bi2Sr2CaCu2O8+x, Tl2Ca2Ba2Cu3Ox, and TlCa2Ba2Cu3Ox are measured with a superconducting quantum interference device (SQUID). The noise power spectrum generally scales as 1/f (f is frequency) from 1 Hz to 1 kHz, increases with temperature, and decreases in higher-quality films. It is proportional to the magnetic field B in which the sample is cooled, at least in the range 0.1 mT < B < 3 mT. A model of thermally activated vortex motion is developed which explains the dependence of the noise on frequency, temperature, current, and applied magnetic field. The pinning potential is idealized as an ensemble of double wells, each with a different activation energy separating the two states. From the noise measurements, this model yields the distribution of pinning energies in the samples, the vortex hopping distance, the number density of mobile vortices, and the restoring force on a vortex at a typical pinning site. The distribution of pinning energies in YBa2Cu3O7-x shows a broad peak below 0.1 eV. The small ambient magnetic field, and the detection of noise even in the absence of a driving force, insure that the measured pinning energies are characteristic of isolated vortices near thermal equilibrium. The observed vortex density in fields much less than 0.1 mT is too large to be explained by the ambient field, suggesting a mechanism intrinsic to the sample which produces trapped vortices.

  11. Magnetic flux creep in HTSC and Anderson-Kim theory

    International Nuclear Information System (INIS)

    Lykov, A.N.

    2014-01-01

    The theoretical and experimental data on flux creep in high-temperature superconductors (HTSC) were analyzed in the review paper. On the one hand, the main attention is paid to the most striking experimental results which have had a significant influence on the investigations of flux creep in HTSC. On the other hand, the analysis of theoretical studies is concentrated on the works, which explain the features of flux creep on the basis of the Anderson-Kim (AK) theory modifications, and received previously unsufficient attention. However, it turned out that the modified AK theory could explain a lot of features of flux creep in HTSC: the scaling behaviour of current-voltage curves of HTSC, the finite rate of flux creep at ultra low temperatures, the logarithmic dependence of effective pinning potential as a function of transport current and its decrease with temperature. The harmonic potential field which is used in this approach makes it possible to solve accurately the both problems: viscous vortex motion and flux creep in this field. Moreover the distribution of pinning potential and the interaction of vortices with each other are taken into account in the approach. Thus, the modification of the AK theory consists, essentially, in its detailed elaboration and approaching to real situations in superconductors

  12. Experimental friction coefficients for bovine cartilage measured with a pin-on-disk tribometer: testing configuration and lubricant effects.

    Science.gov (United States)

    Shi, Liu; Sikavitsas, Vassilios I; Striolo, Alberto

    2011-01-01

    The friction coefficient between wet articular cartilage surfaces was measured using a pin-on-disk tribometer adopting different testing configurations: cartilage-on-pin vs. alumina-on-disk (CA); cartilage-on-pin vs. cartilage-on-disk (CC); and alumina-on-pin vs. cartilage-on-disk (AC). Several substances were dissolved in the phosphate buffered saline (PBS) solution to act as lubricants: 10,000 molecular weight (MW) polyethylene glycol (PEG), 100,000 MW PEG, and chondroitin sulfate (CS), all at 100 mg/mL concentration. Scanning electron microscopy photographs of the cartilage specimens revealed limited wear due to the experiment. Conducting the experiments in PBS solutions we provide evidence according to which a commercial pin-on-disk tribometer allows us to assess different lubrication mechanisms active in cartilage. Specifically, we find that the measured friction coefficient strongly depends on the testing configuration. Our results show that the friction coefficient measured under CC and AC testing configurations remains very low as the sliding distance increases, probably because during the pin displacement the pores present in the cartilage replenish with PBS solution. Under such conditions the fluid phase supports a large load fraction for long times. By systematically altering the composition of the PBS solution we demonstrate the importance of solution viscosity in determining the measured friction coefficient. Although the friction coefficient remains low under the AC testing configuration in PBS, 100 mg/mL solutions of both CS and 100,000 MW PEG in PBS further reduce the friction coefficient by ~40%. Relating the measured friction coefficient to the Hersey number, our results are consistent with a Stribeck curve, confirming that the friction coefficient of cartilage under the AC testing configuration depends on a combination of hydrodynamic, boundary, and weep bearing lubrication mechanisms.

  13. PIN architecture for ultrasensitive organic thin film photoconductors.

    Science.gov (United States)

    Jin, Zhiwen; Wang, Jizheng

    2014-06-17

    Organic thin film photoconductors (OTFPs) are expected to have wide applications in the field of optical communications, artificial vision and biomedical sensing due to their great advantages of high flexibility and low-cost large-area fabrication. However, their performances are not satisfactory at present: the value of responsivity (R), the parameter that measures the sensitivity of a photoconductor to light, is below 1 AW(-1). We believe such poor performance is resulted from an intrinsic self-limited effect of present bare blend based device structure. Here we designed a PIN architecture for OTFPs, the PIN device exhibits a significantly improved high R value of 96.5 AW(-1). The PIN architecture and the performance the PIN device shows here should represent an important step in the development of OTFPs.

  14. PIN architecture for ultrasensitive organic thin film photoconductors

    Science.gov (United States)

    Jin, Zhiwen; Wang, Jizheng

    2014-01-01

    Organic thin film photoconductors (OTFPs) are expected to have wide applications in the field of optical communications, artificial vision and biomedical sensing due to their great advantages of high flexibility and low-cost large-area fabrication. However, their performances are not satisfactory at present: the value of responsivity (R), the parameter that measures the sensitivity of a photoconductor to light, is below 1 AW−1. We believe such poor performance is resulted from an intrinsic self-limited effect of present bare blend based device structure. Here we designed a PIN architecture for OTFPs, the PIN device exhibits a significantly improved high R value of 96.5 AW−1. The PIN architecture and the performance the PIN device shows here should represent an important step in the development of OTFPs. PMID:24936952

  15. Danish calculations of the NEACRP pin-power benchmark

    International Nuclear Information System (INIS)

    Hoejerup, C.F.

    1994-01-01

    This report describes calculations performed for the NEACRP pin-power benchmark. The calculations are made with the code NEM2D, a diffusion theory code based on the nodal expansion method. (au) (15 tabs., 15 ills., 5 refs.)

  16. Investigation of pinning in MgB2 superconductors

    International Nuclear Information System (INIS)

    Mohammad, S.; Reissner, M.; Steiner, W.; Bauer, E.; Giovannini, M.

    2006-01-01

    Full text: The pinning behaviour of bulk MgB 2 superconductors is peculiar in many respects. Pinning seems to be stronger than in classical high T C materials and there seems to be no weak link problem in these compounds, giving hope to produce bulk samples and wires with current densities appropriate for technical applications. But, although many studies concerning the pinning behaviour in this compound appeared in recent years, the results are still contradictory. In the present work we present results of an investigation of the pinning behaviour by magnetic relaxation measurements of three MgB 2 samples: a pure one, a sample with 8 at% Al substitution and a sample with 10 wt% of SiC admixture. A comparison of different analyses methods is given. (author)

  17. Pin Worm Survey on Infant School Children in Gunma Prefecture

    OpenAIRE

    佐藤, 久美子; 阿部, 美幸; 伊藤, 恵美; 金田, 聡子; 関口, 直美; 深町, 容子; 松渕, ユカ子; 柳, 博美; 鈴木, 守

    1991-01-01

    Pin worms (Enterobius vermicularis) are the commonest intestinal parasite in Japan. Examination of this worm infection is usually made by microscopic observation on the swab taken on a scothch tape. We conducted a survey of pin worm infection among infant school children of 4-6 years old. Suitable days for swab examination were studied by comparing the detection rate according to the consecutive days tested. Results were summarized as follows: 1. Three hundred sixteen children (172 boys and 1...

  18. Domain Walls in Helical Magnets: Elasticity and Pinning

    OpenAIRE

    Nattermann, Thomas

    2012-01-01

    Recently completely new types of domain walls (DWs) have been discovered in helical magnets, consisting generically of a regular array of {\\it pairs} of magnetic vortex lines \\cite{Li+12}. Only for special orientations DWs are free of vortices. In this article we calculate their elastic and pinning properties, using the pitch angle $\\theta$ as a small parameter. In particular we show that vortex free DWs exhibit long range elasticity which makes them very stiff and suppresses their pinning by...

  19. AtPIN: Arabidopsis thaliana Protein Interaction Network

    Directory of Open Access Journals (Sweden)

    Silva-Filho Marcio C

    2009-12-01

    Full Text Available Abstract Background Protein-protein interactions (PPIs constitute one of the most crucial conditions to sustain life in living organisms. To study PPI in Arabidopsis thaliana we have developed AtPIN, a database and web interface for searching and building interaction networks based on publicly available protein-protein interaction datasets. Description All interactions were divided into experimentally demonstrated or predicted. The PPIs in the AtPIN database present a cellular compartment classification (C3 which divides the PPI into 4 classes according to its interaction evidence and subcellular localization. It has been shown in the literature that a pair of genuine interacting proteins are generally expected to have a common cellular role and proteins that have common interaction partners have a high chance of sharing a common function. In AtPIN, due to its integrative profile, the reliability index for a reported PPI can be postulated in terms of the proportion of interaction partners that two proteins have in common. For this, we implement the Functional Similarity Weight (FSW calculation for all first level interactions present in AtPIN database. In order to identify target proteins of cytosolic glutamyl-tRNA synthetase (Cyt-gluRS (AT5G26710 we combined two approaches, AtPIN search and yeast two-hybrid screening. Interestingly, the proteins glutamine synthetase (AT5G35630, a disease resistance protein (AT3G50950 and a zinc finger protein (AT5G24930, which has been predicted as target proteins for Cyt-gluRS by AtPIN, were also detected in the experimental screening. Conclusions AtPIN is a friendly and easy-to-use tool that aggregates information on Arabidopsis thaliana PPIs, ontology, and sub-cellular localization, and might be a useful and reliable strategy to map protein-protein interactions in Arabidopsis. AtPIN can be accessed at http://bioinfo.esalq.usp.br/atpin.

  20. Behavior of a bundle of fast fuel pins under irradiation

    International Nuclear Information System (INIS)

    Marbach, G.; Millet, P.; Robert, J.; Languille, A.

    1979-01-01

    In the French design of fuel elements for fast reactors, great deformation of pins can bring about interaction with the hexagonal tube through the spacer wires. The change in such bundles is described here when the diameter of the cladding increases and the outcome of this reaction (bending and ovalization of pins) is calculated with a simplified model. It is shown that the results achieved agree well with the experimental observations [fr

  1. Pin and roller attachment system for ceramic blades

    Science.gov (United States)

    Shaffer, J.E.

    1995-07-25

    In a turbine, a plurality of blades are attached to a turbine wheel by way of a plurality of joints which form a rolling contact between the blades and the turbine wheel. Each joint includes a pin and a pair of rollers to provide rolling contact between the pin and an adjacent pair of blades. Because of this rolling contact, high stress scuffing between the blades and the turbine wheel reduced, thereby inhibiting catastrophic failure of the blade joints. 3 figs.

  2. Pin tract infection after uniplanar external fixation of open fractures at ...

    African Journals Online (AJOL)

    Pin tract infection after uniplanar external fixation of open fractures at a national, teaching and referral hospital. ... Background: Pin tract infection is the most common complication of external fixation accounting for 43% of complications. The presence of a pin tract infection leads to subsequent pin loosening and fixation ...

  3. Delayed Fission Product Gamma-Ray Transmission Through Low Enriched UO2 Fuel Pin Lattices in Air

    Energy Technology Data Exchange (ETDEWEB)

    Trumbull, TH [Rensselaer Polytechnic Inst., Troy, NY (United States)

    2004-10-18

    The transmission of delayed fission-product gamma rays through various arrangements of low-enriched UO2 fuel pin lattices in an air medium was studied. Experimental measurements, point-kernel and Monte Carlo photon transport calculations were performed to demonstrate the shielding effect of ordered lattices of fuel pins on the resulting gamma-ray dose to a detector outside the lattice. The variation of the gamma-ray dose on the outside of the lattice as a function of radial position, the so-called “channeling” effect, was analyzed. Techniques for performing experimental measurements and data reduction at Rensselaer Polytechnic Institute’s Reactor Critical Facility (RCF) were derived. An experimental apparatus was constructed to hold the arrangements of fuel pins for the measurements. A gamma-ray spectroscopy system consisting of a sodium-iodide scintillation detector was used to collect data. Measurements were made with and without a collimator installed. A point-kernel transport code was developed to map the radial dependence of the gamma-ray flux. Input files for the Monte Carlo code, MCNP, were also developed to accurately model the experimental measurements. The results of the calculations were compared to the experimental measurements. In order to determine the delayed fission-product gamma-ray source for the calculations, a technique was developed using a previously written code, DELBG and the reactor state-point data obtained during the experimental measurements. Calculations were performed demonstrating the effects of material homogenization on the gamma-ray transmission through the fuel pin lattice.Homogeneous and heterogeneous calculations were performed for all RCF fuel pin lattices as well as for a typical commercial pressurized water reactor fuel bundle. The results of the study demonstrated the effectiveness of the experimental measurements to isolate the channeling effect of delayed fission-product gamma-rays through lattices of RCF fuel pins

  4. Aperture averaging in strong oceanic turbulence

    Science.gov (United States)

    Gökçe, Muhsin Caner; Baykal, Yahya

    2018-04-01

    Receiver aperture averaging technique is employed in underwater wireless optical communication (UWOC) systems to mitigate the effects of oceanic turbulence, thus to improve the system performance. The irradiance flux variance is a measure of the intensity fluctuations on a lens of the receiver aperture. Using the modified Rytov theory which uses the small-scale and large-scale spatial filters, and our previously presented expression that shows the atmospheric structure constant in terms of oceanic turbulence parameters, we evaluate the irradiance flux variance and the aperture averaging factor of a spherical wave in strong oceanic turbulence. Irradiance flux variance variations are examined versus the oceanic turbulence parameters and the receiver aperture diameter are examined in strong oceanic turbulence. Also, the effect of the receiver aperture diameter on the aperture averaging factor is presented in strong oceanic turbulence.

  5. Interplay between collective pinning and artificial defects on domain wall propagation in Co/Pt multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Rodriguez, G; Hierro-Rodriguez, A; Perez-Junquera, A; Montenegro, N; Alameda, J M; Velez, M [Dept. Fisica, Universidad de Oviedo-CINN, 33007 Oviedo (Spain); Menendez, J L [Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN). Principado de Asturias-Consejo Superior de Investigaciones Cientificas (CSIC)-Univ. Oviedo -UO, Parque Tecnologico de Asturias, 33428 Llanera (Spain); Ravelosona, D, E-mail: mvelez@uniovi.e [Institut d' Electronique Fondamentale, UMR CNRS 8622, Univ. Paris Sud, 91405 Orsay Cedex (France)

    2010-08-04

    The interplay between collective pinning on intrinsic structural defects and artificial pinning at a patterned hole is studied in magnetic multilayers with perpendicular anisotropy. The pinning strength of a patterned hole is measured through its efficiency to stop domain wall (DW) propagation into a consecutive unpatterned nanowire section (using antisymmetric magnetoresistance to detect the direction of DW propagation) whereas collective pinning is characterized by the field dependence of DW velocity. Close to room temperature, collective pinning becomes weaker than artificial pinning so that pinning at the hole compensates nucleation-pad geometry, blocking DW propagation across the nanowire.

  6. Interplay between collective pinning and artificial defects on domain wall propagation in Co/Pt multilayers

    International Nuclear Information System (INIS)

    Rodriguez-Rodriguez, G; Hierro-Rodriguez, A; Perez-Junquera, A; Montenegro, N; Alameda, J M; Velez, M; Menendez, J L; Ravelosona, D

    2010-01-01

    The interplay between collective pinning on intrinsic structural defects and artificial pinning at a patterned hole is studied in magnetic multilayers with perpendicular anisotropy. The pinning strength of a patterned hole is measured through its efficiency to stop domain wall (DW) propagation into a consecutive unpatterned nanowire section (using antisymmetric magnetoresistance to detect the direction of DW propagation) whereas collective pinning is characterized by the field dependence of DW velocity. Close to room temperature, collective pinning becomes weaker than artificial pinning so that pinning at the hole compensates nucleation-pad geometry, blocking DW propagation across the nanowire.

  7. Repeat biopsy in patients with initial diagnosis of PIN; La biopsia ripetuta nei pazienti con diagnosi iniziale di PIN

    Energy Technology Data Exchange (ETDEWEB)

    De Matteis, Massimo [Azienda Ospedaliera Policlinico S. Orsola-Malpighi, Bologna (Italy). UO Radiologia Albertoni; Poggi, Cristina; De Martino, Antonietta; Pavlica, Pietro [Azienda Ospedaliera Policlinico S. Orsola-Malpighi, Bologna (Italy). UO Radiologia Palagi, Dipartimento area radiologica; Corti, Barbara [Azienda Ospedaliera Policlinico S. Orsola-Malpighi, Bologna (Italy). UO Anatomia ed istologia patologica, Dipartimento oncologico ed ematologico; Barozzi, Libero [Azienda Ospedaliera Policlinico S. Orsola-Malpighi, Bologna (Italy). UO Radiologia d' urgenza, Dipartimento emergenze ed accettazione

    2005-09-15

    Purpose. Prostatic intra-epithelial neoplasia (PIN) is considered a pre-malignant lesion and the main precursor of invasive prostatic adenocarcinoma. A PIN diagnosis established by prostate needle biopsy poses a difficult clinical management. problem. We retrospectively reviewed our three-year experience in order to identify criteria for referring patients to repeat biopsy. Materials and methods. We reviewed the repeat biopsy records of 72 patients in whom PIN had been detected on initial US-guided needle biopsy of the prostate. All the patients had a minimum of 6 biopsy cores taken, and they all had PSA > 4 ng/ml. Results. Adenocarcinoma was detected in 15 patients out of 50 (30%) with an initial diagnosis of low-grade PIN and in 10 patients out of 22 (45.4%) with high grade PIN, in 7 out of 18 (39%) in whom PSA levels had decreased during the observation interval, in 16 patients out of 46 (35%) in whom the PSA had increased and in 2 patients out of 8 (25%) with stable PSA. Conclusions. Our results seem to confirm that PIN can be considered a precursor of prostatic adenocarcinoma or a histological alteration often associated with it. Patients with low-grade PIN and particularly those with high-grade PIN should be regularly subjected to repeat biopsy at short intervals due to the high frequency of the final diagnosis of carcinoma. No agreement has been reached on the time interval between the first and the second biopsy. The PSA changes during the observation period are not a statistically significant parameter to suggest the repetition of prostatic biopsy. [Italian] Scopo. La neoplasia prostatica intraepiteliale (PIN) e considerata una lesione premaligna ed il precursore principale dell'adenocarcinoma prostatico infiltrante. La diagnosi di PIN ottenuta con l'agobiopsia della prostata rappresenta un difficile problema gestionale clinico. In una valutazione retrospettiva della nostra esperienza di 3 anni si e cercato di individuare i criteri che possano

  8. Equations of motion for two-phase flow in a pin bundle of a nuclear reactor

    International Nuclear Information System (INIS)

    Chawla, T.C.; Ishii, M.

    1978-01-01

    By performing Eulerian area averaging over a channel area of the local continuity, momentum, and energy equations for single phase turbulent flow and assuming each phase in two-phase flows to be continuum but coupled by the appropriate 'jump' conditions at the interface, the corresponding axial macroscopic balances for two-fluid model in a pin bundle are obtained. To determine the crossflow, a momentum equation in transverse (to the gap between the pins) direction is obtained for each phase by carrying out Eulerian segment averaging of the local momentum equation, where the segment is taken parallel to the gap. By considering the mixture as a whole, a diffusion model based on drift-flux velocity is formulated. In the axial direction it is expressed in terms of three mixture conservation equations of mass, momentum, and energy with one additional continuity equation for the vapor phase. For the determination of crossflow, transverse momentum equation for a mixture is obtained. It is considered that the previous formulation of the two-phase flow based on the 'slip' flow model and the integral subchannel balances using finite control volumes is inadequate in that the model is heuristic and, a priori, assumes the order of magnitude of the terms, also the model is incomplete and incorrect when applied to two-phase mixtures in thermal non-equilibrium such as during accidental depressurization of a water cooled reactor. The governing equations presented are shown to be a very formal and sound physical basis and are indispensable for physically correct methods of analyzing two-phase flows in a pin bundle. (author)

  9. Direct observation of nanometer-scale pinning sites in (Nd.sub.0.33./sub.Eu.sub.0.20./sub.Gd.sub.0.47./sub.)Ba.sub.2./sub.Cu.sub.3./sub.O.sub.7-δ./sub. single crystals

    Czech Academy of Sciences Publication Activity Database

    Das, P.; Koblischka, M.R.; Turner, S.; van Tendeloo, G.; Wolf, Th.; Jirsa, Miloš; Hartmann, U.

    2008-01-01

    Roč. 83, č. 3 (2008), 37005/p1-37005/p4 ISSN 0295-5075 Institutional research plan: CEZ:AV0Z10100520 Keywords : vortex lattices * flux pinning * flux creep * critical currents * effects of crystal defects * doping and substitution Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.203, year: 2008

  10. Subchannel and Computational Fluid Dynamic Analyses of a Model Pin Bundle

    Energy Technology Data Exchange (ETDEWEB)

    Gairola, A.; Arif, M.; Suh, K. Y. [Seoul National Univ., Seoul (Korea, Republic of)

    2014-05-15

    The current study showed that the simplistic approach of subchannel analysis code MATRA was not good in capturing the physical behavior of the coolant inside the rod bundle. With the incorporation of more detailed geometry of the grid spacer in the CFX code it was possible to approach the experimental values. However, it is vital to incorporate more advanced turbulence mixing models to more realistically simulate behavior of the liquid metal coolant inside the model pin bundle in parallel with the incorporation of the bottom and top grid structures. In the framework of the 11{sup th} international meeting of International Association for Hydraulic Research and Engineering (IAHR) working group on the advanced reactor thermal hydraulics a standard problem was conducted. The quintessence of the problem was to check on the hydraulics and heat transfer in a novel pin bundle with different pitch to rod diameter ratio and heat flux cooled by liquid metal. The standard problem stems from the field of nuclear safety research with the idea of validating and checking the performances of computer codes against the experimental results. Comprehensive checks between the two will succor in improving the dependability and exactness of the codes used for accident simulations.

  11. Strongly coupled interaction between a ridge of fluid and an inviscid airflow

    KAUST Repository

    Paterson, C.

    2015-07-01

    © 2015 AIP Publishing LLC. The behaviour of a steady thin sessile or pendent ridge of fluid on an inclined planar substrate which is strongly coupled to the external pressure gradient arising from an inviscid airflow parallel to the substrate far from the ridge is described. When the substrate is nearly horizontal, a very wide ridge can be supported against gravity by capillary and/or external pressure forces; otherwise, only a narrower (but still wide) ridge can be supported. Classical thin-aerofoil theory is adapted to obtain the governing singular integro-differential equation for the profile of the ridge in each case. Attention is focused mainly on the case of a very wide sessile ridge. The effect of strengthening the airflow is to push a pinned ridge down near to its edges and to pull it up near to its middle. At a critical airflow strength, the upslope contact angle reaches the receding contact angle at which the upslope contact line de-pins, and continuing to increase the airflow strength beyond this critical value results in the de-pinned ridge becoming narrower, thicker, and closer to being symmetric in the limit of a strong airflow. The effect of tilting the substrate is to skew a pinned ridge in the downslope direction. Depending on the values of the advancing and receding contact angles, the ridge may first de-pin at either the upslope or the downslope contact line but, in general, eventually both contact lines de-pin. The special cases in which only one of the contact lines de-pins are also considered. It is also shown that the behaviour of a very wide pendent ridge is qualitatively similar to that of a very wide sessile ridge, while the important qualitative difference between the behaviour of a very wide ridge and a narrower ridge is that, in general, for the latter one or both of the contact lines may never de-pin.

  12. Manipulating light with strongly modulated photonic crystals

    International Nuclear Information System (INIS)

    Notomi, Masaya

    2010-01-01

    Recently, strongly modulated photonic crystals, fabricated by the state-of-the-art semiconductor nanofabrication process, have realized various novel optical properties. This paper describes the way in which they differ from other optical media, and clarifies what they can do. In particular, three important issues are considered: light confinement, frequency dispersion and spatial dispersion. First, I describe the latest status and impact of ultra-strong light confinement in a wavelength-cubic volume achieved in photonic crystals. Second, the extreme reduction in the speed of light is reported, which was achieved as a result of frequency dispersion management. Third, strange negative refraction in photonic crystals is introduced, which results from their unique spatial dispersion, and it is clarified how this leads to perfect imaging. The last two sections are devoted to applications of these novel properties. First, I report the fact that strong light confinement and huge light-matter interaction enhancement make strongly modulated photonic crystals promising for on-chip all-optical processing, and present several examples including all-optical switches/memories and optical logics. As a second application, it is shown that the strong light confinement and slow light in strongly modulated photonic crystals enable the adiabatic tuning of light, which leads to various novel ways of controlling light, such as adiabatic frequency conversion, efficient optomechanics systems, photon memories and photons pinning.

  13. Influence of pin geometry on mechanical and structural properties of butt friction stir welded 2024-T351 aluminum alloy

    Directory of Open Access Journals (Sweden)

    Radisavljević Igor Z.

    2015-01-01

    Full Text Available The aim of this work was to investigate the combined effect of small difference in pin geometry, together with rotation and welding speed on the weldability, mechanical and structural properties of FSW 2024-T351 Al plates. The only difference in tool pin design was the shape of thread: regular and rounded. Specimens were welded using rotation rate of 750 rev/min and welding speeds of 73 and 93 mm/min. In all four cases, specimens were defect free, with good or acceptable weld surface. Modification in pin design showed strong influence on macro structure and hardness distribution. Weak places are identified as low hardness zone, close to the nugget zone and are in good agreement with fracture location in tensile testing. Weld efficiency, as a measure of weld quality, are better in case of 310 tool, while UTS values can differ up to 13% for the equal welding parameters. Therefore, it can be assumed that small modification in tool design, particularly in pin geometry, can have great influence on weld formation and mechanical properties.

  14. Engineered flux-pinning centers in BSCCO TBCCO and YBCO superconductors

    Science.gov (United States)

    Goretta, K.C.; Lanagan, M.T.; Miller, D.J.; Sengupta, S.; Parker, J.C.; Hu, J.; Balachandran, U.; Siegel, R.W.; Shi, D.

    1999-07-27

    A method of preparing a high temperature superconductor is disclosed. A method of preparing a superconductor includes providing a powdered high temperature superconductor and a nanophase material. These components are combined to form a solid compacted mass with the material disposed in the polycrystalline high temperature superconductor. This combined mixture is rapidly heated, forming a dispersion of nanophase size particles without a eutectic reaction. These nanophase particles can have a flat plate or columnar type morphology. 4 figs.

  15. Crystal Chemical Substitutions of YBa2Cu3O7-d to Enhance Flux Pinning (Postprint)

    Science.gov (United States)

    2012-02-01

    1.015 0.000 0210 J. at0.1 T [98] 0.200 0.350 0.400 0.680 0.700 0.290 1.000 0.190 y 1.019 v, .• oy . PLDfilms 1.027 0.000 0.300 [19] 0.200 2.800...Physica C 314 (1999) 55-68. L. Cao, J. Zegenhagen, Phys. Stat. Sol. 215 (1999) 587-589. C. Kwon , L.R. Kinder, Y. Gim, Y. Fan, J.Y. Coulter, M.P

  16. Three-dimensional vortex pinning by nano-precipitates in a Sm-doped YBa2Cu3O7-x coated conductor

    International Nuclear Information System (INIS)

    Chen, Z; Feldmann, D M; Song, X; Kim, S I; Gurevich, A; Reeves, J L; Xie, Y Y; Selvamanickam, V; Larbalestier, D C

    2007-01-01

    We report on the thickness and angular dependence of the critical current density J c (H,θ), the irreversibility field H irr , and the bulk pinning force F p (H) of a metal-organic chemical vapour deposition (MOCVD) grown YBa 2 Cu 3 O 7-x (YBCO) coated conductor, which contains ∼17 vol% of ∼10 nm sized (Y,Sm) 2 O 3 precipitates with an average spacing of ∼10-15 nm. Some surface porosity and amorphous second-phase particles on the scale of ∼0.5-1 μm appear to reduce the current-carrying cross-section, which controls the magnitude of J c but not the vortex pinning. We observed an enhanced H irr ∼9 T at 77 K along the c-axis which, like the shape of J c (H) and F p (H), was independent of thickness as the sample was milled down to ∼0.16 μm. Angular-dependent measurements of J c showed the usual excess vortex pinning along the c-axis and along the ab-plane, but with a background that could only be fitted with an unusually small anisotropy parameter of 3, which, like the high H irr and the thickness-independent shape of F p (H), we ascribe to strong vortex pinning centre interactions. Together, these measurements show very different behaviour from most pulsed-laser-deposited films, which exhibit strong thickness-dependent properties. We ascribe the present different results to the dense array of small, insulating precipitates, which act as strong pinning centres and produce strong three-dimensional (3D) vortex pinning, because their separation of 10-15 nm is always much smaller than the film thickness

  17. Reconstruction of pin burnup characteristics from nodal calculations in hexagonal geometry

    International Nuclear Information System (INIS)

    Yang, W.S.; Finck, P.J.; Khalil, H.S.

    1990-01-01

    A reconstruction method has been developed for recovering pin burnup characteristics from fuel cycle calculations performed in hexagonal-z geometry using the nodal diffusion option of the DIF3D/REBUS-3 code system. Intra-modal distributions of group fluxes, nuclide densities, power density, burnup, and fluence are efficiently computed using polynomial shapes constrained to satisfy nodal information. The accuracy of the method has been tested by performing several numerical benchmark calculations and by comparing predicted local burnups to values measured for experimental assemblies in EBR-11. The results indicate that the reconstruction methods are quite accurate, yielding maximum errors in power and nuclide densities that are less than 2% for driver assemblies and typically less than 5% for blanket assemblies. 14 refs., 2 figs., 5 tabs

  18. Unusual magneto-transport of YBa2Cu3O7−δ films due to the interplay of anisotropy, random disorder and nanoscale periodic pinning

    International Nuclear Information System (INIS)

    Trastoy, J; Rouco, V; Bernard, R; Briatico, J; Villegas, J E; Ulysse, C; Faini, G; Palau, A; Puig, T; Lesueur, J

    2013-01-01

    We study the general problem of a manifold of interacting elastic lines whose spatial correlations are strongly affected by the competition between random and ordered pinning. This is done through magneto-transport experiments with YBa 2 Cu 3 O 7−δ thin films that contain a periodic vortex pinning array created via masked ion irradiation, in addition to the native random pinning. The strong field-matching effects we observe suggest the prevalence of periodic pinning, and indicate that at the matching field each vortex line is bound to an artificial pinning site. However, the vortex-glass transition dimensionality—quasi-two dimensional instead of the usual three dimensional—evidences reduced vortex-glass correlations along the vortex line. This is also supported by an unusual angular dependence of the magneto-resistance, which greatly differs from that of Bose-glass systems. A quantitative analysis of the angular magneto-resistance allows us to link this behaviour to the enhancement of the system anisotropy, a collateral effect of the ion irradiation. (paper)

  19. Alpha particles spectrometer with photodiode PIN; Espectrometro de particulas alfa con fotodiodo PIN

    Energy Technology Data Exchange (ETDEWEB)

    Chacon R, A.; Hernandez V, R.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidades Academicas de Estudios Nucleares e Ingenieria Electrica, Calle Cipres No. 10, Fracc. La Penuela, 09869 Zacatecas (Mexico); Ramirez G, J. [Instituto Nacional de Estadistica Geografia e Informatica, Direccion General de Innovacion y Tecnologia de Informacion, Av. Heroes de Nacozari Sur 2301, Fracc. Jardines del Parque, 20276 Aguascalientes (Mexico)], e-mail: achruiz@hotmail.com

    2009-10-15

    The radiation propagates in form of electromagnetic waves or corpuscular radiation; if the radiation energy causes ionization in environment that crosses it is considered ionizing radiation. To detect radiation several detectors types are used, if the radiation are alpha particles are used detectors proportional type or trace elements. In this work the design results, construction and tests of an alpha particles spectrometer are presented, which was designed starting from a photodiode PIN type. The system design was simulated with a code for electronic circuits. With results of simulation phase was constructed the electronic phase that is coupled to a multichannel analyzer. The resulting electronic is evaluated analyzing the electronic circuit performance before an alphas triple source and alpha radiation that produce two smoke detectors of domestic use. On the tests phase we find that the system allows obtain, in a multichannel, the pulses height spectrum, with which we calibrate the system. (Author)

  20. Flux-flow noise in type II superconductors

    International Nuclear Information System (INIS)

    Choe, H.M.; Ziel, A. van der

    1976-01-01

    This paper discusses flux-flow noise in type II superconductors. A theoretical expression is given for flux-flow noise in a rectangular sample with two probes, and compared with earlier models; the differences are not very large. Experiments give no flicker noise below 20 μW/mm 2 dissipation at 4.2 K, whereas much larger dissipations can be tolerated below the lambda temperature before flicker noise sets in. The shape of the spectrum at elevated frequencies is of the 1/f type, as predicted by the theory, followed by a probe size effect at still higher frequencies. The noise is much larger than would be expected from single fluxoids; this is caused by the flux bundle effect which, in turn, is due to pinning and fluxoid interaction. The size of the flux bundles can be determined from the data, it decreases with increasing current. (Auth.)

  1. Pin1 and neurodegeneration: a new player for prion disorders?

    Directory of Open Access Journals (Sweden)

    Elisa Isopi

    2015-07-01

    Full Text Available Pin1 is a peptidyl-prolyl isomerase that catalyzes the cis/trans conversion of phosphorylated proteins at serine or threonine residues which precede a proline. The peptidyl-prolyl isomerization induces a conformational change of the proteins involved in cell signaling process. Pin1 dysregulation has been associated with some neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and Huntington's disease. Proline-directed phosphorylation is a common regulator of these pathologies and a recent work showed that it is also involved in prion disorders. In fact, prion protein phosphorylation at the Ser-43-Pro motif induces prion protein conversion into a disease-associated form. Furthermore, phosphorylation at Ser-43-Pro has been observed to increase in the cerebral spinal fluid of sporadic Creutzfeldt-Jakob Disease patients. These findings provide new insights into the pathogenesis of prion disorders, suggesting Pin1 as a potential new player in the disease. In this paper, we review the mechanisms underlying Pin1 involvement in the aforementioned neurodegenerative pathologies focusing on the potential role of Pin1 in prion disorders.

  2. Cluster synchronization for directed community networks via pinning partial schemes

    International Nuclear Information System (INIS)

    Hu Cheng; Jiang Haijun

    2012-01-01

    Highlights: ► Cluster synchronization for directed community networks is proposed by pinning partial schemes. ► Each community is considered as a whole. ► Several novel pinning criteria are derived based on the information of communities. ► A numerical example with simulation is provided. - Abstract: In this paper, we focus on driving a class of directed networks to achieve cluster synchronization by pinning schemes. The desired cluster synchronization states are no longer decoupled orbits but a set of un-decoupled trajectories. Each community is considered as a whole and the synchronization criteria are derived based on the information of communities. Several pinning schemes including feedback control and adaptive strategy are proposed to select controlled communities by analyzing the information of each community such as indegrees and outdegrees. In all, this paper answers several challenging problems in pinning control of directed community networks: (1) What communities should be chosen as controlled candidates? (2) How many communities are needed to be controlled? (3) How large should the control gains be used in a given community network to achieve cluster synchronization? Finally, an example with numerical simulations is given to demonstrate the effectiveness of the theoretical results.

  3. Pin-Type Gas Cooled Reactor for Nuclear Electric Propulsion

    Science.gov (United States)

    Wright, Steven A.; Lipinski, Ronald J.

    2003-01-01

    This paper describes a point design for a pin-type Gas-Cooled Reactor concept that uses a fuel pin design similar to the SP100 fuel pin. The Gas-Cooled Reactor is designed to operate at 100 kWe for 7 years plus have a reduced power mode of 20% power for a duration of 5 years. The power system uses a gas-cooled, UN-fueled, pin-type reactor to heat He/Xe gas that flows directly into a recuperated Brayton system to produce electricity. Heat is rejected to space via a thermal radiator that unfolds in space. The reactor contains approximately 154 kg of 93.15 % enriched UN in 313 fuel pins. The fuel is clad with rhenium-lined Nb-1Zr. The pressures vessel and ducting are cooled by the 900 K He/Xe gas inlet flow or by thermal radiation. This permits all pressure boundaries to be made of superalloy metals rather than refractory metals, which greatly reduces the cost and development schedule required by the project. The reactor contains sufficient rhenium (a neutron poison) to make the reactor subcritical under water immersion accidents without the use of internal shutdown rods. The mass of the reactor and reflectors is about 750 kg.

  4. Generation of clusters in complex dynamical networks via pinning control

    International Nuclear Information System (INIS)

    Li Kezan; Fu Xinchu; Small, Michael

    2008-01-01

    Many real-world networks show community structure, i.e., groups (or clusters) of nodes that have a high density of links within them but with a lower density of links between them. In this paper, by applying feedback injections to a fraction of network nodes, various clusters are synchronized independently according to the community structure generated by the group partition of the network (cluster synchronization). This control is achieved by pinning (i.e. applying linear feedback control) to a subset of the network nodes. Those pinned nodes are selected not randomly but according to the topological structure of communities of a given network. Specifically, for a given group partition of a network, those nodes with direct connections between groups must be pinned in order to achieve cluster synchronization. Both the local stability and global stability of cluster synchronization are investigated. Taking the tree-shaped network and the most modular network as two particular examples, we illustrate in detail how the pinning strategy influences the generation of clusters. The simulations verify the efficiency of the pinning schemes used in this paper

  5. Performance of electrical contact pins near a nuclear explosion

    International Nuclear Information System (INIS)

    Ragan, C.E.; Silbert, M.G.; Ellis, A.N.; Robinson, E.E.; Daddario, M.J.

    1977-09-01

    The pressures attainable in equation-of-state studies using nuclear-explosion-driven shock waves greatly exceed those that can be reached in normal laboratory conditions. However, the diagnostic instrumentation must survive in the high-radiation environment present near such an explosion. Therefore, a set of experiments were fielded on the Redmud event to test the feasibility of using electrical contact pins in this environment. In these experiments a 60-cm-high shield of boron-lead was placed on the rack lid approximately 1 m from the device. A sample consisting of slabs of molybdenum and 238 U was placed on top of the shield, and twelve electrical contact pins were embedded to five different depths in the materials. Five different multiplexing-charging circuits were used for the pins, and a piezoelectric quartz gauge was placed on top of the uranium to obtain an estimate of the fission-energy deposition. All of the charged pins survived the radiation and produced signals indicating shock arrival. The uncertainty in determining the pin-closure time was approximately 3 ns. The signal from the quartz gauge corresponded to a pressure that was consistent with the calculated neutron fluence

  6. MICRO PIN ARRAY DETECTOR (MIPA): FIRST TEST RESULTS.

    Energy Technology Data Exchange (ETDEWEB)

    REHAK,P.; SMITH,G.C.; WARREN,J.B.; YU,B.

    1999-06-28

    A novel gas proportional detector, consisting of an array of pins immersed into a cathode made out of closely packed hexagonals has been developed. The resulting geometry of the detector is 3 dimensional. Electron multiplication is limited to a region in close proximity to the tip of each pin, where the electric field decreases with distance from the pin at a rate faster than 1/r, the rate that exists in a traditional wire chamber. The multiplication region is limited to a small part of the detector volume leading to stability of operation up to high charge gas gains. The amplification region is located far enough from any dielectric surface that the gas gain is insensitive to the charge state of the surface, a significant benefit compared with many other micro-pattern detectors. The microscopic dimensions of the individual pins of the array result in signals whose total duration is about a microsecond. Two identical, but opposite polarity signals are detected, one on the pin and one on the cathode. Both signals can be used by two independent, charge division, read-out systems to obtain unambiguous x-y position information of the primary ionization.

  7. MICRO PIN ARRAY DETECTOR (MIPA): FIRST TEST RESULTS.

    Energy Technology Data Exchange (ETDEWEB)

    REHAK,P.; SMITH,G.C.; WARREN,J.B.; YU,B.

    1999-06-28

    A novel gas proportional detector, consisting of an array of pins immersed into a cathode made out of closely packed hexagonals has been developed. The resulting geometry of the detector is 3 dimensional. Electron multiplication is limited to a region in close proximity to the tip of each pin, where the electric field decreases with distance from the pin at a rate faster than l/r, the rate that exists in a traditional wire chamber. The multiplication region is limited to a small part of the detector volume leading to stability of operation up to high charge gas gains. The amplification region is located far enough from any dielectric surface that the gas gain is insensitive to the charge state of the surface, a significant benefit compared with many other micro-pattern detectors. The microscopic dimensions of the individual pins of the array result in signals whose total duration is about a microsecond. Two identical, but opposite polarity signals are detected, one on the pin and one on the cathode. Both signals can be used by two independent, charge division, read-out systems to obtain unambiguous x-y position information of the primary ionization.

  8. Numerical study and optimizing on micro square pin-fin heat sink for electronic cooling

    International Nuclear Information System (INIS)

    Zhao, Jin; Huang, Shanbo; Gong, Liang; Huang, Zhaoqin

    2016-01-01

    Micro pin-fin heat sink, characterized by low thermal resistance, compact structure and uniform temperature distribution along the flow direction, is effective and valuable for thermal management of electronic devices. To enhance the cooling performance of the micro square pin-fin heat sink, a geometry optimizing method changing pin-fin porosity and pin-fin located angle is proposed in this paper. The flow and heat transfer characteristics were studied numerically and the geometry of the micro square pin-fin heat sink was optimized. To reveal the characteristics and advantages of the micro square pin-fin heat sink, the comparison between the square pin-fin and the column pin-fin was made. Numerical results indicate that both the pin-fin porosity and located angle are important for the cooling capacity and thermal performance of the micro square pin-fin heat sink; the optimal porosity and located angle for thermal performance are 0.75 and 30° respectively. Furthermore, micro heat sinks with the optimized square pin-fin present better thermal performance than micro column pin-fin heat sinks, which implies that there is great potential to employ micro square pin-fin heat sinks for thermal management on electronic devices with high energy density. - Highlights: • An optimization method on geometry is proposed for micro square pin-fin heat sink. • Pin-fin porosity and pin-fin located angle are important on thermal performance. • Heat sinks with optimized square pin-fin hold higher cooling capacity than column pin-fin.

  9. Pin Tool Geometry Effects in Friction Stir Welding

    Science.gov (United States)

    Querin, J. A.; Rubisoff, H. A.; Schneider, J. A.

    2009-01-01

    In friction stir welding (FSW) there is significant evidence that material can take one of two different flow paths when being displaced from its original position in front of the pin tool to its final position in the wake of the weld. The geometry of the pin tool, along with the process parameters, plays an important role in dictating the path that the material takes. Each flow path will impart a different thermomechanical history on the material, consequently altering the material microstructure and subsequent weld properties. The intention of this research is to isolate the effect that different pin tool attributes have on the flow paths imparted on the FSWed material. Based on published weld tool geometries, a variety of weld tools were fabricated and used to join AA2219. Results from the tensile properties and microstructural characterization will be presented.

  10. Radiation detectors of PIN type for X-rays

    International Nuclear Information System (INIS)

    Ramirez-Jimenez, F.J.

    2003-01-01

    In this laboratory session, tree experiments are proposed: the measurement of X-ray energy spectra from radioactive sources with a high resolution cooled Si-Li detector, with a room temperature PIN diode and the measurement of the response of a PIN diode to the intensity of X-rays of radio-diagnostic units. The spectra obtained with the Si-Li detector help to understand the energy distribution of X-rays and are used as a reference to compare the results obtained with the PIN diode. Measurements in medical X-ray machines are proposed. Low cost, simple electronic instruments and systems are used as tools to make measurements in X-ray units used in radio-diagnostic

  11. Quality assurance of metallic fuel pins using Eddy current technique

    International Nuclear Information System (INIS)

    Sasi, B.; Thirunavukkarasu, S.; Rao, B.P.C.; Jayakumar, T.; Baldev Raj

    2009-01-01

    Metallic fuels (U-Pu-Zr) is promising for future fast reactors in view of their higher breeding ratio and burn-up as compared to oxide, carbide and other ceramic fuels. The metallic fuel pins are made of T91 tubes filled with fuel slugs with sodium as bonding material. Quality assurance of metallic fuel pins using non destructive evaluation (NDE) techniques is important. For this, eddy current (EC) technique is a natural choice in view of its sensitivity, speed, versatility and ease of use. NDE of metallic fuel pins comprises of detection of defects in T91 tubes, defects in metallic fuel slugs (2.84 mm diameter) and voids in sodium. For these inspection requirements, separate EC techniques would be employed and in this direction, finite element (FE) modelling has been performed and experimental simulation studies have been carried out. This paper discusses the results of these studies

  12. Transverse commensurability effect for vortices on periodic pinning arrays

    Energy Technology Data Exchange (ETDEWEB)

    Reichhardt, Charles [Los Alamos National Laboratory; Reichhardt, Cynthia J [Los Alamos National Laboratory

    2008-01-01

    Using computer simulations, we demonstrate a type of commensurability that occurs for vortices moving longitudinally through periodic pinning arrays in the presence of an additional transverse driving force. As a function of vortex density, there is a series of broad maxima in the transverse critical depinning force that do not fall at the matching fields where the number of vortices equals an integer multiple of the number of pinning sites. The commensurability effects are associated with dynamical states in which evenly spaced structures consisting of one or more moving rows of vortices form between rows of pinning sites. Remarkably, the critical transverse depinning force can be more than an order of magnitude larger than the longitudinal depinning force.

  13. Identification of IAA transport inhibitors including compounds affecting cellular PIN trafficking by two chemical screening approaches using maize coleoptile systems.

    Science.gov (United States)

    Nishimura, Takeshi; Matano, Naoyuki; Morishima, Taichi; Kakinuma, Chieko; Hayashi, Ken-Ichiro; Komano, Teruya; Kubo, Minoru; Hasebe, Mitsuyasu; Kasahara, Hiroyuki; Kamiya, Yuji; Koshiba, Tomokazu

    2012-10-01

    The monocot coleoptile tip region has been generally supposed to be the source of IAA to supply IAA to basal parts by the polar IAA transport system, which results in gravi- and phototropic curvature of coleoptiles. Based on this IAA transport system and gravitropism of maize coleoptiles, we have developed two screening methods to identify small molecules from a large chemical library that inhibit IAA transport. The methods detect molecules that affect (i) gravitropic curvature of coleoptiles; and (ii) the amount of IAA transported from the tip. From 10,000 chemicals, eight compounds were identified and categorized into two groups. Four chemicals in group A decreased IAA transport from the tip, and increased endogenous IAA levels in the tip. The structures of two compounds resembled that of 1-N-naphthylphthalamic acid (NPA), but those of the other two differed from structures of known IAA transport inhibitors. Four chemicals in group B strongly inhibited IAA transport from the tip, but IAA levels at the tip were only slightly affected. At higher concentrations, group B compounds inhibited germination of Arabidopsis, similarly to brefeldin A (BFA). Analysis of the cellular distribution of PIN2-green fluorescent protein (GFP) and PIN1-GFP in Arabidopsis revealed that one of the four chemicals in group B induced internalization of PIN1 and PIN2 proteins into vesicles smaller than BFA bodies, suggesting that this compound affects cellular vesicle trafficking systems related to PIN trafficking. The eight chemicals identified here will be a useful tool for understanding the mechanisms of IAA transport in plants.

  14. Sessile droplet de-pinning: new life for gravimetric data.

    Science.gov (United States)

    Chan, Kwaichow B; Pierce, Scott M

    2007-02-01

    Using three different types of surfaces as exemplars, we report a gravimetric method as a viable tool for studying the de-pinning process. Namely, the de-pin time, tau(d) (the time required for a horizontal sessile droplet to de-pin at the triple phase line on a given substrate), is estimated without using a time consuming and expensive video imaging system. This is made possible by deciphering the non-linear portion of mass vs time data of an evaporating sessile droplet. Typical gravimetric glass-substrate evaporative mass loss vs time data has two regimes: a long, linear regime followed by a short, non-linear regime. Traditionally, researchers extract only the evaporation rate of a droplet from the linear regime but discard (by truncating the data) or ignore (thus deriving no information from) the non-linear regime. The origin of the linear to non-linear transition, found almost universally in gravimetric data, persists unremarked upon. By constructing three very different types of surfaces and comparing gravimetric data with video imaging data taken simultaneously, we report the transition is correlated to the onset of the de-pinning event in each case. This realization enables us to measure the de-pin time, tau(d), with gravimetric data only; i.e., without the video system, gathering more information from gravimetric data than previously considered. The method has application in estimating the de-pin time of a droplet deposited on a substrate that yields poor top-view contrast for videography, such as a water droplets on silicon wafers or glass substrates. Finally, gravimetric data is more accurate for evaporation modeling when substrate/droplet interaction areas are not circular.

  15. Creep relaxation of fuel pin bending and ovalling stresses

    International Nuclear Information System (INIS)

    Chan, D.P.; Jackson, R.J.

    1979-06-01

    Analytical methods for calculating fuel pin cladding bending and ovalling stresses due to pin bundle-duct mechanical interaction taking into account nonlinear creep are presented. Calculated results are in close agreement with finite element results by MARC-CDC program. The methods are used to investigate the effect of creep on the FTR fuel cladding bending and ovalling stresses. It is concluded that the cladding of 316 SS 20% CW and reference design has high creep rates in the FTR core region to keep the bending and ovalling stresses to low levels

  16. Medical Gas Cylinder with Mismatched Colour and Pin Index

    Directory of Open Access Journals (Sweden)

    Mukherjee S

    2014-08-01

    Full Text Available The medical gas cylinders have various safety features to prevent the administration of wrong gas to the patient. Most of the features have visual impact (colour, label, markings on the cylinder body except pin index system on the cylinder valve, so error in this feature is difficult to analyze and is highly unpredictable. We had received one such cylinder in our institution where all other features (label, colour, marking pointed to nitrous oxide except the pin index which resembled with that of oxygen

  17. Fuel pin failure in the PFR/TREAT experiments

    International Nuclear Information System (INIS)

    Herbert, R.; Hunter, C.W.; Kramer, J.M.; Wood, M.H.; Wright, A.E.

    1986-01-01

    The PFR/TREAT safety testing programme involves the transient testing of fresh and pre-irradiated UK and US fuel pins. This paper summarizes the experimental and calculational results obtained to date on fuel pin failure during transient overpower (resulting from an accidental addition of resolivity) and transient undercooling followed by overpower (arising from an accidental stoppage of the primary sodium circulating pumps) accidents. Companion papers at this conference address: (I) the progress and future plans of the programme, and (II) post-failure material movements

  18. Analysis of the porosity distribution of mixed oxide pins

    International Nuclear Information System (INIS)

    Lieblich, M.; Lopez, J.

    1987-01-01

    In the frame of the Joint Irradiation Program IVO-FR2-Vg7 between the Centre of Nuclear Research of Karlsruhe (KfK), the irradiation of 30 mixed-oxide fuel rods in the FR2 experimental reactor was carried out. The pins were located in 10 single-walled NaK capsules. The behaviour of the fuel during its burnup was studied, mainly, the rest-porosity and cracking distribution in the pellet, partial densification, etc. In this work 3 pins from the capsule No. 165 were analyzed. The experimental results (pore and cracking profiles) were interpreted by the fuel rod code SATURN. (Author) 20 refs

  19. Establishment of the PIN within the Colombian party system

    Directory of Open Access Journals (Sweden)

    Vanessa Ortiz López

    2012-12-01

    Full Text Available This paper is a review of the legislative elections held in Colombia in 2010 and one of their main results, the establishment of the National Integration Party (PIN. The authors offer an analysis of articles that appeared in printed media, taking into consideration such variables as financing, legal constitution, popular acceptance and settling time. In this way, the authors attempt to demonstrate how the PIN managed to get a place in the political system and what are the consequences of this development, in particular, as the Department of Valle del Cauca is concerned.

  20. OpenFLUX: efficient modelling software for 13C-based metabolic flux analysis

    Directory of Open Access Journals (Sweden)

    Nielsen Lars K

    2009-05-01

    Full Text Available Abstract Background The quantitative analysis of metabolic fluxes, i.e., in vivo activities of intracellular enzymes and pathways, provides key information on biological systems in systems biology and metabolic engineering. It is based on a comprehensive approach combining (i tracer cultivation on 13C substrates, (ii 13C labelling analysis by mass spectrometry and (iii mathematical modelling for experimental design, data processing, flux calculation and statistics. Whereas the cultivation and the analytical part is fairly advanced, a lack of appropriate modelling software solutions for all modelling aspects in flux studies is limiting the application of metabolic flux analysis. Results We have developed OpenFLUX as a user friendly, yet flexible software application for small and large scale 13C metabolic flux analysis. The application is based on the new Elementary Metabolite Unit (EMU framework, significantly enhancing computation speed for flux calculation. From simple notation of metabolic reaction networks defined in a spreadsheet, the OpenFLUX parser automatically generates MATLAB-readable metabolite and isotopomer balances, thus strongly facilitating model creation. The model can be used to perform experimental design, parameter estimation and sensitivity analysis either using the built-in gradient-based search or Monte Carlo algorithms or in user-defined algorithms. Exemplified for a microbial flux study with 71 reactions, 8 free flux parameters and mass isotopomer distribution of 10 metabolites, OpenFLUX allowed to automatically compile the EMU-based model from an Excel file containing metabolic reactions and carbon transfer mechanisms, showing it's user-friendliness. It reliably reproduced the published data and optimum flux distributions for the network under study were found quickly ( Conclusion We have developed a fast, accurate application to perform steady-state 13C metabolic flux analysis. OpenFLUX will strongly facilitate and

  1. Radon flux measurement methodologies

    International Nuclear Information System (INIS)

    Nielson, K.K.; Rogers, V.C.

    1984-01-01

    Five methods for measuring radon fluxes are evaluated: the accumulator can, a small charcoal sampler, a large-area charcoal sampler, the ''Big Louie'' charcoal sampler, and the charcoal tent sampler. An experimental comparison of the five flux measurement techniques was also conducted. Excellent agreement was obtained between the measured radon fluxes and fluxes predicted from radium and emanation measurements

  2. Overexpression of PvPin1, a Bamboo Homolog of PIN1-Type Parvulin 1, Delays Flowering Time in Transgenic Arabidopsis and Rice

    Directory of Open Access Journals (Sweden)

    Zhigang Zheng

    2017-09-01

    Full Text Available Because of the long and unpredictable flowering period in bamboo, the molecular mechanism of bamboo flowering is unclear. Recent study showed that Arabidopsis PIN1-type parvulin 1 (Pin1At is an important floral activator and regulates floral transition by facilitating the cis/trans isomerization of the phosphorylated Ser/Thr residues preceding proline motifs in suppressor of overexpression of CO 1 (SOC1 and agamous-like 24 (AGL24. Whether bamboo has a Pin1 homolog and whether it works in bamboo flowering are still unknown. In this study, we cloned PvPin1, a homolog of Pin1At, from Phyllostachys violascens (Bambusoideae. Bioinformatics analysis showed that PvPin1 is closely related to Pin1-like proteins in monocots. PvPin1 was widely expressed in all tested bamboo tissues, with the highest expression in young leaf and lowest in floral bud. Moreover, PvPin1 expression was high in leaves before bamboo flowering then declined during flower development. Overexpression of PvPin1 significantly delayed flowering time by downregulating SOC1 and AGL24 expression in Arabidopsis under greenhouse conditions and conferred a significantly late flowering phenotype by upregulating OsMADS56 in rice under field conditions. PvPin1 showed subcellular localization in both the nucleus and cytolemma. The 1500-bp sequence of the PvPin1 promoter was cloned, and cis-acting element prediction showed that ABRE and TGACG-motif elements, which responded to abscisic acid (ABA and methyl jasmonate (MeJA, respectively, were characteristic of P. violascens in comparison with Arabidopsis. On promoter activity analysis, exogenous ABA and MeJA could significantly inhibit PvPin1 expression. These findings suggested that PvPin1 may be a repressor in flowering, and its delay of flowering time could be regulated by ABA and MeJA in bamboo.

  3. Pin1, a new player in the fate of HIF-1α degradation: an hypothetical mechanism inside vascular damage as Alzheimer’s disease risk factor.

    Directory of Open Access Journals (Sweden)

    Elena eLonati

    2014-01-01

    Full Text Available Aetiology of neurodegenerative mechanisms underlying Alzheimer's disease (AD are still under elucidation. The contribution of cerebrovascular deficiencies (such as cerebral ischemia/stroke has been strongly endorsed in recent years. Reduction of blood supply leading to hypoxic condition is known to activate cellular responses mainly controlled by hypoxia-inducible transcription factor-1 (HIF-1. Thus alterations of oxygen responsive HIF-1α subunit in the central nervous system may contribute to the cognitive decline, especially influencing mechanisms associated to APP (amyloid precursor protein amyloidogenic metabolism. Although HIF-1α protein level is known to be regulated by von Hippel-Lindau (VHL ubiquitin-proteasome system, it has been recently suggested that Gsk-3β (glycogen synthase kinase-3β promotes a VHL-independent HIF-1α degradation. Here we provide evidences that in rat primary hippocampal cell cultures, HIF-1α degradation might be mediated by a synergic action of Gsk-3β and Pin1 (peptidyl-prolyl cis/trans isomerase. In post-ischemic conditions, such as those mimicked with oxygen glucose deprivation (OGD, HIF-1α protein level increases remaining unexpectedly high for long time after normal condition restoration jointly with the increase of LDH (lactate dehydrogenase and BACE1 (β-secretase 1 protein expression (70% and 140% respectively. Interestingly the Pin1 activity decreases about 40%-60% and Pin1S16 inhibitory phosphorylation significantly increases, indicating that Pin1 binding to its substrate and enzymatic activity are reduced by treatment. Co-immunoprecipitation experiments demonstrate that HIF-1α/Pin1 in normoxia are associated, and that in presence of specific Pin1 and Gsk-3β inhibitors their interaction is reduced in parallel to an increase of HIF-1α protein level. Thus we suggest that in post-OGD neurons the high level of HIF-1α might be due to Pin1 binding ability and activity reduction which affects HIF-1

  4. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  5. A modified barbell-shaped PNN-PZT-PIN piezoelectric ceramic energy harvester

    Science.gov (United States)

    Gao, Xiangyu; Wu, Jingen; Yu, Yang; Dong, Shuxiang

    2017-11-01

    The quaternary system of relaxor-ferroelectric based Pb(Ni1/3Nb2/3)O3-Pb(ZrxTi1-x)O3-Pb(In0.5Nb0.5)O3 (PNN-PZT-PIN) piezoelectric ceramic at the morphotropic phase boundary was investigated via the solid reaction method. The optimized ceramic with excellent electric properties of ɛr = 8084, d33 = 977 pC/N, kp = 0.61, and Ec = 3.0 kV/cm was fabricated into d33-mode discs with separated surface electrodes, which were arranged in a series connection and, then as a piezo-stack, assembled into a barbell-shaped energy harvester that could bear a strong mechanical vibration. It is found that under a vibration mass-induced bending moment, the energy harvester produces an open circuit voltage of 26.4 Vp-p at the acceleration of 2.5 g at a load of 1.56 MΩ, which is two times higher in comparison to one without surface electrode separation. Its power output is 30 μW at the acceleration of 1 g and 104 μW at 2.5 g, which are even six times higher than that of a previously reported barbell-shaped energy harvester at room-temperature with the same acceleration. The enhanced power output can be attributed to (i) the excellent piezoelectric response of PNN-PZT-PIN ceramic and (ii) harvesting positive and negative charges from the separated surface electrodes other than a full surface electrode on piezoelectric discs under bending moment. Furthermore, the practical test was performed within a car engine, which shows that the PNN-PZT-PIN piezoelectric ceramic is a promising candidate for vibration energy harvesting.

  6. A numerical method for PCM-based pin fin heat sinks optimization

    International Nuclear Information System (INIS)

    Pakrouh, R.; Hosseini, M.J.; Ranjbar, A.A.; Bahrampoury, R.

    2015-01-01

    Highlights: • Optimization of PCM-based heat sink by using the Taguchi method. • Derivation of optimal PCM percentage to reach the maximum critical time. • Optimization is performed for four different critical temperatures. • Effective design factors are fins’ height and fins’ number. • The optimum configuration depends on geometric properties and the critical temperature. - Abstract: This paper presents a numerical investigation on geometric optimization of PCM-based pin fin heat sinks. Paraffin RT44HC is used as PCM while the fins and heat sink base is made of aluminum. The fins act as thermal conductivity enhancers (TCEs). The main goal of the study is to obtain the configurations that maximize the heat sink operational time. An approach witch couples Taguchi method with numerical simulations is utilized for this purpose. Number of fins, fins height, fins thickness and the base thickness are parameters which are studied for optimization. In this study natural convection and PCM volume variation during melting process are considered in the simulations. Optimization is performed for different critical temperatures of 50 °C, 60 °C, 70 °C and 80 °C. Results show that a complex relation exists between PCM and TCE volume percentages. The optimal case strongly depends on the fins’ number, fins’ height and thickness and also the critical temperature. The optimum PCM percentages are found to be 60.61% (corresponds to 100 pin fin heat sink with 4 mm thick fins) for critical temperature of 50 °C and 82.65% (corresponds to 100 pin fin heat sink with 2 mm thick fins) for other critical temperatures

  7. Ultrasensitive Ambient Mass Spectrometric Analysis with a Pin-to-Capillary Flowing Atmospheric-Pressure Afterglow Source

    Science.gov (United States)

    Shelley, Jacob T.; Wiley, Joshua S.; Hieftje, Gary M.

    2011-01-01

    The advent of ambient desorption/ionization mass spectrometry has resulted in a strong interest in ionization sources that are capable of direct analyte sampling and ionization. One source that has enjoyed increasing interest is the Flowing Atmospheric-Pressure Afterglow (FAPA). FAPA has been proven capable of directly desorbing/ionizing samples in any phase (solid, liquid, or gas) and with impressive limits of detection (analytes, which ultimately compromised analyte identification and quantification. In the present study, a change in the FAPA configuration from a pin-to-plate to a pin-to-capillary geometry was found to vastly improve performance. Background signals in positive- and negative-ionization modes were reduced by 89% and 99%, respectively. Additionally, the capillary anode strongly reduced the amount of atomic oxygen that could cause oxidation of analytes. Temperatures of the gas stream that interacts with the sample, which heavily influences desorption capabilities, were compared between the two sources by means of IR thermography. The performance of the new FAPA configuration is evaluated through the determination of a variety of compounds in positive- and negative-ion mode, including agrochemicals and explosives. A detection limit of 4 amol was found for the direct determination of the agrochemical ametryn, and appears to be spectrometer-limited. The ability to quickly screen for analytes in bulk liquid samples with the pin-to-capillary FAPA is also shown. PMID:21627097

  8. Effect of III-nitride polarization on V{sub OC} in p-i-n and MQW solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Namkoong, Gon; Boland, Patrick; Foe, Kurniawan; Latimer, Kevin [Department of Electrical and Computer Engineering, Old Dominion University, Applied Research Center, 12050 Jefferson Avenue, Newport News, VA 23606 (United States); Bae, Si-Young; Shim, Jae-Phil; Lee, Dong-Seon [School of Information and Communications, Gwangju Institute of Science and Technology, 261 Cheomdan-gwagiro (Oryong-dong), Buk-gu, Gwangju 500-712 (Korea, Republic of); Jeon, Seong-Ran [Korea Photonics Technology Institute, 971-35, Wolchul-dong, Buk-gu, Gwangju, 500-779 (Korea, Republic of); Doolittle, W. Alan [School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

    2011-02-15

    We performed detailed studies of the effect of polarization on III-nitride solar cells. Spontaneous and piezoelectric polarizations were assessed to determine their impacts upon the open circuit voltages (V{sub OC}) in p-i(InGaN)-n and multi-quantum well (MQW) solar cells. We found that the spontaneous polarization in Ga-polar p-i-n solar cells strongly modifies energy band structures and corresponding electric fields in a way that degrades V{sub OC} compared to non-polar p-i-n structures. In contrast, we found that piezoelectric polarization in Ga-polar MQW structures does not have a large influence on V{sub OC} compared to non-polar MQW structures. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Impact of compound doping on hole and electron balance in p-i-n organic light-emitting diodes

    Directory of Open Access Journals (Sweden)

    Xin-Xin Wang

    2013-10-01

    Full Text Available The fluorescent and phosphorescent p-i-n organic light-emitting diodes (OLEDs with well controllable compound doping have been systematically investigated, where MoO3 and LiF are the effective p-type and n-type dopants, respectively. For both the bulk and interfacial doping, the hole and electron balance in the devices is found to be strongly dependent on the doping configuration, which could either facilitate or compromise the device power efficiency. The impact of the compound doping on the charge balance is further confirmed by the change of the emission region with different doping configuration. The modulation of p-type and n-type doping densities and position is thus essential for optimizing hole and electron balance in p-i-n OLEDs.

  10. Image analysis for remote examination of fuel pins

    International Nuclear Information System (INIS)

    Cook, J.H.; Nayak, U.P.

    1982-01-01

    An image analysis system operating in the Wing 9 Hot Cell Facility at Los Alamos National Laboratory provides quantitative microstructural analyses of irradiated fuels and materials. With this system, fewer photomicrographs are required during postirradiation microstructural examination and data are available for analysis much faster. The system has been used successfully to examine Westinghouse Advanced Reactors Division experimental fuel pins

  11. Pinning an Ion with an Intracavity Optical Lattice

    DEFF Research Database (Denmark)

    Linnet, Rasmus Bogh; Leroux, Ian Daniel; Marciante, Mathieu

    2012-01-01

    We report one-dimensional pinning of a single ion by an optical lattice. A standing-wave cavity produces the lattice potential along the rf-field-free axis of a linear Paul trap. The ion’s localization is detected by measuring its fluorescence when excited by standing-wave fields with the same...

  12. Construction of mammary gland specific expression plasmid pIN ...

    African Journals Online (AJOL)

    Then the neo gene was amplified from plasmid pCDNA3.1 and placed downstream of the β-casein 3' arm as a positive selection marker. In order to analyze the bioactivity of plasmid pIN, it was transfected into the Bcap-37 cell line and injected into goat mammary gland. Western-blotting and quantitative polymerase chain ...

  13. Silicon PIN diode array hybrids for charged particle detection

    International Nuclear Information System (INIS)

    Shapiro, S.L.; Dunwoodie, W.M.; Arens, J.F.; Jernigan, J.G.; Gaalema, S.

    1988-09-01

    We report on the design of silicon PIN diode array hybrids for use as charged particle detectors. A brief summary of the need for vertex detectors is presented. Circuitry, block diagrams and device specifications are included. 8 refs., 7 figs., 1 tab

  14. Review of HEDL fuel pin transient analyses analytical programs

    International Nuclear Information System (INIS)

    Scott, J.H.; Baars, R.E.

    1975-05-01

    Methods for analysis of transient fuel pin performance are described, as represented by the steady-state SIEX code and the PECT series of codes used for steady-state and transient mechanical analyses. The empirical fuel failure correlation currently in use for analysis of transient overpower accidents is described. (U.S.)

  15. Pinning of size-selected Pd nanoclusters on graphite

    NARCIS (Netherlands)

    Gibilisco, S.; Di Vece, M.; Palomba, S.; Faraci, G.; Palmer, R.E.

    2006-01-01

    The production of stable cluster arrays on smooth surfaces has several potential technological applications. We report a study of the pinning of size-selected palladium nanoclusters on the graphite surface. The clusters formed during gas aggregation in vacuum are projected with sufficient kinetic

  16. On pins and needles: how vaccines are portrayed on Pinterest.

    Science.gov (United States)

    Guidry, Jeanine P D; Carlyle, Kellie; Messner, Marcus; Jin, Yan

    2015-09-22

    Vaccination is an effective public health tool for reducing morbidity and mortality caused by infectious diseases. However, increasing numbers of parents question the safety of vaccines or refuse to vaccinate their children outright. The Internet is playing a significant role in the growing voice of the anti-vaccination movement as a growing number of people use the Internet to obtain health information, including information about vaccines. Given the role the Internet plays in providing vaccination-related communication, coupled with limited research in this area, this study focused on the social media platform Pinterest, analyzing 800 vaccine-related pins through a quantitative content analysis. The majority of the pins were anti-vaccine, and most were original posts as opposed to repins. Concerns about vaccine safety and side effects were oft-repeated themes, as was the concept of conspiracy theory. Pro-vaccine pins elicited consistently more engagement than anti-vaccine pins. Health educators and public health organizations should be aware of these dynamics, since a successful health communication campaign should start with an understanding of what and how publics communicate about the topic at hand. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Percutaneous Pin Fixation of Gartland Type I11 Supraconylar ...

    African Journals Online (AJOL)

    This was a prospective study of 40 children with severely displaced (Gartland Type 111) supracondylar fractures of the humerus treated by lateral percutaneous pin fixation together with a 'figure of eight' plaster casting. Their mean age was 6.9 years, the mean follow up was 2 years/. Eighteen (45%) of the patients had ...

  18. ``Pinning strategy": a novel approach for predicting the backbone ...

    Indian Academy of Sciences (India)

    2006-09-06

    Sep 6, 2006 ... In this study, we propose a new method called “pinning strategy” that used this specific feature to predict long protein fragments. Its goal is to define highly probable successions of PBs. It starts from the most probable SW and is then extended with overlapping SWs. Starting from an initial prediction rate of ...

  19. Vortex lattice mobility and effective pinning potentials in the peak ...

    Indian Academy of Sciences (India)

    In that region of field and temperature the mobility of the vortex lattice (VL) is found to be dependent on the dynamical history. Recently we reported evidence that the VL reorganizes and accesses to robust VL configurations (VLCs) with different effective pinning potential wells arising in response to different system histories.

  20. Assemblies and fuel pin behaviour under irradiation in FBR-350

    International Nuclear Information System (INIS)

    Karaulov, V.N.; Blynski, A.P.; Yakovlev, I.L.; Kononova, E.V.

    1998-01-01

    The efficiency of all types of assemblies and fuel pins of the reactor BN-350 is considered in detail. The factors limiting the efficiency are indicated. The behaviour of assemblies with stainless steel ducts is studied. It is shown that the efficiency is restricted in this case by shape and dimensional changes of hexagonal ducts due to radiation swelling and radiation creep of structural materials. The problem of dimensional changes of ducts was solved for cores of reactors BN-350 and BN-600 after testing in BN-350 of experimental assemblies with ducts made of ferritic-martensitic steel 12Cr13Mo2NbVB. For fuel pins of the second type of loading with clad made of stainless steel 0Cr16Ni15Mo3Nb the efficiency is limited by burnup of 13% h.a. and damage dose of 90 dpa. To increase the burnup the core of the BN-350 is supplied by assemblies of modernized type with pins having a large gas plenum and clad made of the stainless steel 0Cr16Ni15Mo2Mn2TiVB that has a good resistance to irradiation. The efficiency of fuel pins of modernized assemblies in the reactor BN-350 core conditions is provided up to 15% h.a. and damage dose 105 dpa. (author)

  1. Pinning strategy": a novel approach for predicting the backbone ...

    Indian Academy of Sciences (India)

    2006-09-06

    Sep 6, 2006 ... In this study, we propose a new method called “pinning strategy” that used this specific feature to predict long protein fragments. Its goal is to define highly probable successions of PBs. It starts from the most probable SW and is then extended with overlapping SWs. Starting from an initial prediction rate of ...

  2. Percutaneous Pin Fixation of Gartland Type I11 Supraconylar ...

    African Journals Online (AJOL)

    S G Lungu M.Med (Orth). Specialist Orthopaedic Surgeon. Zambian Italian Orthopaedic Hospital, Lusaka. Key words: Percutaneous, pin fixation, Gartland type Ill, supracondylar, fractures, and humerus. This was a prospective study of 40 children with severely displaced (Gartland Type 111) supracondylar fractures of the ...

  3. Alternative heat transfer surfaces for AGR fuel pins

    International Nuclear Information System (INIS)

    Wilkie, D.

    1983-01-01

    Advanced gas-cooled reactors employing stainless-steel clad fuel pins must be economical in the use of steel to avoid incurring crippling penalties arising from neutron absorption. Any means of enhancing heat transfer by altering the surface of the pin by the adoption of projections necessitates that these projections are of low height relative to the equivalent diameter of the surrounding passage. This rules out the use of extended surfaces in the form of large fins, which in any case would be ruled out on thermal efficiency grounds owing to the large temperature drop down the poorly conducting steel but it does not rule out the use of many fins of low height. Longitudinal fins of low height for which results have been obtained for single pins tested in smooth circular channels and multi-start ribs for which single-pin and cluster results are available, are considered. The advantages and disadvantages of these and other ideas are considered in relation to the Advanced Gas-cooled Reactor. (author)

  4. Calculation of fuel pin failure timing under LOCA conditions

    International Nuclear Information System (INIS)

    Jones, K.R.; Wade, N.L.; Siefken, L.J.; Straka, M.; Katsma, K.R.

    1992-01-01

    The objective of this research was to develop and demonstrate a methodology for calculation of the time interval between receipt of the containment isolation signals and the first fuel pin failure for loss-of-coolant accidents (LOCAs). Demonstration calculations were performed for a Babcock and Wilcox design (Oconee) and a Westinghouse 4-loop design (Seabrook). Sensitivity studies were performed to assess the impacts of fuel pin burnup, axial peaking factor, break size, emergency core cooling system availability, and main coolant pump trip on these times. The analysis was performed using a four-code approach, comprised of FRAPCON-2, SCDAP/RELAP5/MOD3, TRAC-PF1/MOD1, and FRAP-T6. In addition to the calculation of timing results, this analysis provided a comparison of the capabilities of SCDAP/RELAP5/MOD3 with TRAC-PF1/MOD1 for large-break LOCA analysis. This paper discusses the methodology employed and the code development efforts required to implement the methodology. The shortest time intervals calculated between initiation of containment isolation and fuel pin failure were 11.4 s and 19.1 s for the Babcock and Wilcox and Westinghouse plants, respectively. The FRAP-T6 fuel pin failure times calculated using thermal-hydraulic data generated by SCDAP/RELAP5/MOD3 were more conservative than those calculated using data generated by TRAC-PF1/MOD1

  5. Calculation of fuel pin failure timing under LOCA conditions

    International Nuclear Information System (INIS)

    Jones, K.R.; Wade, N.L.; Siefken, L.J.; Straka, M.; Katsma, K.R.

    1991-10-01

    The objective of this research was to develop and demonstrate a methodology for calculation of the time interval between receipt of the containment isolation signals and the first fuel pin failure for loss-of-coolant accidents (LOCAs). Demonstration calculations were performed for a Babcock and Wilcox (B ampersand W) design (Oconee) and a Westinghouse (W) 4-loop design (Seabrook). Sensitivity studies were performed to assess the impacts of fuel pin burnup, axial peaking factor, break size, emergency core cooling system (ECCS) availability, and main coolant pump trip on these items. The analysis was performed using a four-code approach, comprised of FRAPCON-2, SCDAP/RELAP5/MOD3, TRAC-PF1/MOD1, and FRAP-T6. In addition to the calculation of timing results, this analysis provided a comparison of the capabilities of SCDAP/RELAP5/MOD3 with TRAC-PF1/MOD1 for large-break LOCA analysis. This paper discusses the methodology employed and the code development efforts required to implement the methodology. The shortest time intervals calculated between initiation of containment isolation and fuel pin failure were 11.4 s and 19.1 for the B ampersand W and W plants, respectively. The FRAP-T6 fuel pin failure times calculated using thermal-hydraulic data generated by SCDAP/RELAP5/MOD3 were more conservative than those calculated using data generated by TRAC-PF1/MOD1. 18 refs., 7 figs., 4 tabs

  6. Pin weighing system for the Fuels and Materials Examination Facility

    International Nuclear Information System (INIS)

    Frandsen, G.B.; Mullally, J.A.; Gaal, P.S.

    1981-01-01

    A pin weighing system was designed and built for use in the FMEF Nondestructive Examination Cell. The system provides a 5000 gram capacity with a +- 0.03 gram overall accuracy and a +- 0.02 gram reproducibility. The design incorporates all required features to operate and maintain the system remotely in a hot cell environment

  7. Performance of advanced oxide fuel pins in EBR-II

    International Nuclear Information System (INIS)

    Lawrence, L.A.; Jensen, S.M.; Hales, J.W.; Karnesky, R.A.; Makenas, B.J.

    1986-05-01

    The effects of design and operating parameters on mixed-oxide fuel pin irradiation performance were established for the Hanford Engineering Development Laboratory (HEDL) advanced oxide EBR-II test series. Fourteen fuel pins breached in-reactor with reference 316 SS cladding. Seven of the breaches are attributed to FCMI. Of the remaining seven breached pins, three are attributed to local cladding over-temperatures similar to the breach mechanism for the reference oxide pins irradiated in EBR-II. FCCI was found to be a contributing factor in two high burnup, i.e., 11.7 at. % breaches. The remaining two breaches were attributed to mechanical interaction of UO 2 fuel and fission products accumulated in the lower cladding insulator gap, and a loss of cladding ductility possibly due to liquid metal embrittlement. Fuel smear density appears to have the most significant impact on lifetime. Quantitative evaluations of cladding diameter increases attributed to FCMI, established fuel smear density, burnup, and cladding thickness-to-diameter ratio as the major parameters influencing the extent of cladding strain

  8. Ising antiferromagnet with mobile, pinned, and quenched defects

    Directory of Open Access Journals (Sweden)

    W.Selk

    2005-01-01

    Full Text Available Motivated by recent experiments on (Sr,Ca,La14Cu24O41, a two-dimensional Ising antiferromagnet with mobile, locally pinned and quenched defects is introduced and analyzed using mainly Monte Carlo techniques. The interplay between the arrangement of the defects and the magnetic ordering as well as the effect of an external field are studied.

  9. 1071-IJBCS-Article-Crépin Pene

    African Journals Online (AJOL)

    KODJIO NORBERT

    ://indexmedicus.afro.who.int. Late season sugarcane performance as affected by soil water deficit at the yield formation stage in commercial farms of northern Ivory Coast. Crépin B. PÉNÉ *, Marco H. OUATTARA and Sylvain G. KOULIBALY.

  10. Fuel pins volume measuring installation in hot cells

    International Nuclear Information System (INIS)

    Prokudanov, D.L.; Troitskii, S.V.

    1987-11-01

    The NIIAR Institute has elaborated a method and concepted an installation for determining precisely the fuel pin volume. This determination is based on a fluid measurement level by ultrason. The operation principle and the installation diagram are indicated in this document [fr

  11. Neutron radiography for quality assurance of PHWR fuel pins

    International Nuclear Information System (INIS)

    Chandrasekharan, K.N.; Patil, B.P.; Ghosh, J.K.; Ganguly, C.

    1993-01-01

    Neutron radiography was employed for quality assurance (QA) for advanced PHWR experimental fuel pins containing mixed uranium-plutonium dioxide and thorium-plutonium dioxide pellets. Direct, transfer and track-etch techniques were utilised. The thermal neutron beam facility of APSARA research reactor at Bhabha Atomic Research Centre was used. (author). 5 refs., 16 figs., 2 tabs

  12. Vortex lattice mobility and effective pinning potentials in the peak

    Indian Academy of Sciences (India)

    In that region of field and temperature the mobility of the vortex lattice (VL) is found to be dependent on the dynamical history. Recently we reported evidence that the VL reorganizes and accesses to robust VL configurations (VLCs) with different effective pinning potential wells arising in response to different system histories.

  13. Pin Tract Infection after Uniplanar External Fixation of Open ...

    African Journals Online (AJOL)

    ADMIN

    Regionally, a study by Jellis et al in Lusaka, Zambia, compared the rate of severe pin tract infection in HIV negative and positive ... likelihood of infection such as human immunodeficiency virus infection, diabetes mellitus, liver failure, renal failure, tumours ... Combined Open Tibia-Fibular. And Femur Fractures. 2. 2.7. Totals.

  14. The stress distribution in pin-loaded orthotropic plates

    Science.gov (United States)

    Klang, E. C.; Hyer, M. W.

    1985-01-01

    The performance of mechanically fastened composite joints was studied. Specially, a single-bolt connector was modeled as a pin-loaded, infinite plate. The model that was developed used two dimensional, complex variable, elasticity techniques combined with a boundary collocation procedure to produce solutions for the problem. Through iteration, the boundary conditions were satisfied and the stresses in the plate were calculated. Several graphite epoxy laminates were studied. In addition, parameters such as the pin modulus, coefficient of friction, and pin-plate clearance were varied. Conclusions drawn from this study indicate: (1) the material properties (i.e., laminate configuration) of the plate alter the stress state and, for highly orthotropic materials, the contact stress deviates greatly from the cosinusoidal distribution often assumed; (2) friction plays a major role in the distribution of stresses in the plate; (3) reversing the load direction also greatly effects the stress distribution in the plate; (4) clearance (or interference) fits change the contact angle and thus the location of the peak hoop stress; and (5) a rigid pin appears to be a good assumption for typical material systems.

  15. ER-localized auxin transporter PIN8 regulates auxin homeostasis and male gametophyte development in Arabidopsis.

    Science.gov (United States)

    Ding, Zhaojun; Wang, Bangjun; Moreno, Ignacio; Dupláková, Nikoleta; Simon, Sibu; Carraro, Nicola; Reemmer, Jesica; Pěnčík, Aleš; Chen, Xu; Tejos, Ricardo; Skůpa, Petr; Pollmann, Stephan; Mravec, Jozef; Petrášek, Jan; Zažímalová, Eva; Honys, David; Rolčík, Jakub; Murphy, Angus; Orellana, Ariel; Geisler, Markus; Friml, Jiří

    2012-07-03

    Auxin is a key coordinative signal required for many aspects of plant development and its levels are controlled by auxin metabolism and intercellular auxin transport. Here we find that a member of PIN auxin transporter family, PIN8 is expressed in male gametophyte of Arabidopsis thaliana and has a crucial role in pollen development and functionality. Ectopic expression in sporophytic tissues establishes a role of PIN8 in regulating auxin homoeostasis and metabolism. PIN8 co-localizes with PIN5 to the endoplasmic reticulum (ER) where it acts as an auxin transporter. Genetic analyses reveal an antagonistic action of PIN5 and PIN8 in the regulation of intracellular auxin homoeostasis and gametophyte as well as sporophyte development. Our results reveal a role of the auxin transport in male gametophyte development in which the distinct actions of ER-localized PIN transporters regulate cellular auxin homoeostasis and maintain the auxin levels optimal for pollen development and pollen tube growth.

  16. Fracture resistance of composite and amalgam cores retained by pins coated with new adhesive resins.

    Science.gov (United States)

    Tjan, A H; Dunn, J R; Grant, B E

    1992-06-01

    This study determined the effects of coating pins with either Panavia EX or with 4-META (Cover-Up) materials on the fracture resistance of pin-retained amalgam and composite cores. Gold-plated stainless steel (TMS) and titanium (Filpin) self-threading pins were used. Findings of this study corroborated the findings of several other studies that the use of pins reduces the fracture resistance of restorations. However, coating the pins with adhesion promoters such as Panavia EX and 4-META materials has been found to be effective in improving the fracture resistance. Cross-preference was observed between TMS and Filpin pins; that is, Panavia material coating was more effective with TMS pins, while 4-META was more effective with Filpin pins.

  17. Investigation on flow and heat transfer characteristics in rectangular channel with drop-shaped pin fins

    Directory of Open Access Journals (Sweden)

    Fengming Wang

    2012-12-01

    Full Text Available The flow and heat transfer characteristics inside a rectangular channel embedded with pin fins were numerically and experimentally investigated. Several differently shaped pin fins (i.e., circular, elliptical, and drop-shaped with the same cross-sectional areas were compared in a staggered arrangement. The Reynolds number based on the obstructed section hydraulic diameter (defined as the ratio of the total wetted surface area to the open duct volume available for flow was varied from 4800 to 8200. The more streamlined drop-shaped pin fins were better at delaying or suppressing separation of the flow passing through them, which decreased the aerodynamic penalty compared to circular pin fins. The heat transfer enhancement of the drop-shaped pin fins was less than that of the circular pin fins. In terms of specific performance parameters, drop-shaped pin fins are a promising alternative configuration to circular pin fins.

  18. Vortex Dynamics in Superconductors with Different Types of Pinning Potentials

    International Nuclear Information System (INIS)

    Laguna, Maria Fabiana

    2001-01-01

    In this work we study the behavior of the vortex system in the mixed state of a type II superconductor when it interacts with different kinds of pinning potentials. To do this, we perform numerical simulations in the presence of an external magnetic field, by making use of two different approaches.One corresponds to a Langevin simulation of the three dimensional XY model or Josephson-junction network, whereas the other corresponds to a Molecular dynamics simulation of two dimensional point-like vortices.We analyze the transport properties of highly anisotropic superconductors with different kinds of topological disorder in the configuration in which the external field is applied perpendicular to the CuO planes.We found that for systems with point defects the activation energy is the same for the two components of the resistivity, while in systems with columnar defects the activation energies can be different.We also study the structure, phase transitions and transport properties of the vortex system when the external magnetic field lies parallel to the planes in layered superconductors. We analyze the stability of different phases at low temperatures and show under which conditions the smectic phase is stable.Our results indicate the presence of the smectic phase in an intermediate range of temperatures.We have studied a vortex array in a periodic pinning potential with triangular and kagome geometries.We obtain the ground state vortex configurations and calculate some thermodynamic quantities for different magnetic fields.We observe several stages of lattice pinning and melting and we characterize different phases and transitions between them.Finally, simulating the Bitter pinning effect over the vortex system, we study static and dynamic properties of the vortex system in the presence of the surface Bitter pinning and the bulk pinning.We found low temperature structures similar to those obtained experimentally.We analyze the dynamics of the nucleation and growth

  19. Report of the collaboration project for research and development of sphere-pac fuel among JNC-PSI-NRG (1). Planning, fuel design, pin fabrication

    International Nuclear Information System (INIS)

    Morihira, Masayuki; Ozawa, Takayuki; Tomita, Yutaka; Suzuki, Masahiro; Kihara, Yoshiyuki; Shigetome, Yoshiaki; Kohno, Shusaku

    2004-07-01

    The collaboration project concerning sphere-pac fuel among JNC, Swiss PSI (Paul Scherrer Institut) and Dutch NRG (Nuclear Research and Consultancy Group) is in progress. Final target of the project is comparative irradiation tests of sphere-pac fuel in the HFR (High Flux Reactor) in Petten in the Netherlands with pellet type fuel and vipack fuel. Total 16 fuel segments (8 pins) of these three types of fuel are planned to be irradiated. Two sphere-pac fuel segments contain 5%Np in addition to 20%Pu-MOX. Other segments contain no Np. The objective of the irradiation tests is to obtain the restructuring data in the early beginning of life for SPF as well as power-to-melt test data for the potential study of SPF. At the same time introduction of modeling technique for irradiation performance analysis, fuel design, fuel fabrication is also important objective for JNC. Fabrication of irradiation test pins was completed till May 2003 in PSI. After transportation of the fuel pins to Petten, two times of irradiation were performed in January to March in 2004 and now post irradiation tests are in progress. Later two irradiations will be done till the autumn in 2004. This report summarized the basic plan, fuel design, and fabrication of irradiation test pins concerning this collaboration project. (author)

  20. Comparative prediction of irradiation test of CNFT and Cise prototypes of CIRENE fuel pins, a prediction by transuranus M1V1J12 code

    International Nuclear Information System (INIS)

    Suwardi

    2014-01-01

    A prototype of fuel pin design for HWR by CIRENE has been realized by Center for Nuclear Fuel Technology CNFT-BATAN. The prototype will be irradiated in PRTF Power Ramp Test (PRTF). The facility has been installed inside RSG-GA Siwabessy at Serpong. The present paper reports the preparation of experimentation and prediction of irradiation test. One previous PCI test report is found in, written by Lysell G and Valli G in 1973. The CNFT fuel irradiation test parameter is adapted to both PRTF and power loop design for RSG-GAS reactor in Serpong mainly the maxima of: rod length, neutrons flux, total power of rod, and power ramp rate. The CNFT CIRENE prototype design has been reported by Futichah et al 2007 and 2010. The AEC-India HWR fuel pin is of 19/22 fuel bundle design has also been evaluated as comparison. The first PCI test prediction has experiment comparison for Cise pin. The second prediction will be used for optimizing the design of ramp test for CNFT CIRENE fuel pin prototype. (author)

  1. Transfixation pinning and casting of radial-ulnar fractures in calves: A review of three cases

    OpenAIRE

    St-Jean, Guy; Debowes, Richard M.

    1992-01-01

    We reviewed the medical records of three calves with radial-ulnar fractures which were reduced and stabilized by transfixation pinning and casting. Multiple Steinmann pins were placed transversely through proximal and distal fracture fragments and the pin ends were incorporated in fiberglass cast material after fracture reduction. Cast material was placed from proximal to distal radius and served as an external frame to maintain pin position and fracture reduction.

  2. Heat flux viscosity in collisional magnetized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C., E-mail: cliu@pppl.gov [Princeton University, Princeton, New Jersey 08544 (United States); Fox, W. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Bhattacharjee, A. [Princeton University, Princeton, New Jersey 08544 (United States); Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2015-05-15

    Momentum transport in collisional magnetized plasmas due to gradients in the heat flux, a “heat flux viscosity,” is demonstrated. Even though no net particle flux is associated with a heat flux, in a plasma there can still be momentum transport owing to the velocity dependence of the Coulomb collision frequency, analogous to the thermal force. This heat-flux viscosity may play an important role in numerous plasma environments, in particular, in strongly driven high-energy-density plasma, where strong heat flux can dominate over ordinary plasma flows. The heat flux viscosity can influence the dynamics of the magnetic field in plasmas through the generalized Ohm's law and may therefore play an important role as a dissipation mechanism allowing magnetic field line reconnection. The heat flux viscosity is calculated directly using the finite-difference method of Epperlein and Haines [Phys. Fluids 29, 1029 (1986)], which is shown to be more accurate than Braginskii's method [S. I. Braginskii, Rev. Plasma Phys. 1, 205 (1965)], and confirmed with one-dimensional collisional particle-in-cell simulations. The resulting transport coefficients are tabulated for ease of application.

  3. New Universal Tribometer as Pin or Ball-on-Disc and Reciprocating Pin-on-Plate Types

    Directory of Open Access Journals (Sweden)

    H. Kaleli

    2016-06-01

    Full Text Available The present paper contains a description of a new Universal Tribometer design which enables simulation of different contact and test types such as pin-on-disc, ball-on-disc and linear reciprocating tests. There are many models of wear Tribometer in the world market. These devices are manufactured by various companies abroad and are imported to our country. Cost of this devices start from 50.000 euros and goes to hundreds of thousands of euros. One of the most commonly used of this device is Reciprocating Pin-on-Plate Tribo Test Machine. This wear tester is produced at a low limited cost within the KAP (Scientifical Research Project Coordinator of Yıldız Technical University. The test machine can work including three types of Tribotest rigs (Reciprocating Pin-on-Plate, Pin-on-Disc and Ball-on-Disc. It is designed to operate also at high temperatures up to 500 ˚C. The new piece of equipment allows instrumented tribological testing of piston ring and cylinder liner samples at low and high temperatures and boundary lubrication conditions of any typical gasoline or Diesel engines. Some friction results were shown in boundary lubricating conditions between piston ring and cylinder liner sliding pairs describing Tribotest machine is driven by AC servo motor which is more accurate than DC motor.

  4. Refabrication of spent fuel pins provided with instrumentation by means of the FABRICE process

    International Nuclear Information System (INIS)

    Garcia, A.; Malard, J.P.; Mery, M.; Vouillot, M.

    1986-05-01

    The Fabrice ''hot cell refabrication'' process for small pins from very long irradiated fuel elements was developed at the CEA to allow parametic studies of the irradiation behavior of pins from nuclear power plants. The present note describes the adaptation of techniques to the fabrication of pins provided with important instrumentations [fr

  5. Use of a modified transfixation pin cast for treatment of comminuted phalangeal fractures in horses.

    Science.gov (United States)

    Rossignol, Fabrice; Vitte, Amélie; Boening, Josef

    2014-01-01

    To (1) report a modified transfixation pin cast technique, using dorsal recumbency for fracture reduction, distal positioning of the pins in the epiphysis and distal metaphysis, and a hybrid cast, combining plaster of Paris (POP) and fiberglass casting, and (2) report outcome in 11 adult horses. Case series. Adult horses (n = 11) with comminuted phalangeal fractures. Horses were anesthetized and positioned in dorsal recumbency. The phalangeal fracture was reduced by limb traction using a cable attached to the hoof. Screw fixation in lag fashion of fracture fragments was performed when possible. Transfixation casting was performed using two 6.3 mm positive profile centrally threaded pins with the 1st pin placed in the epiphysis of the metacarpus/tarsus at the center of, or slightly proximal to, the condylar fossa and the 2nd one 3-4 cm proximal. A hybrid cast was applied. Forelimbs were involved in 9 horses and the hind limb in 2. Pins were maintained for a minimum of 6 weeks. No pin loosening was observed at the time of removal (6-8 weeks). A pony fractured the distal aspect of the metacarpus at the proximal pin. Nine horses survived (82%); none of the horses developed septic arthritis despite the distal location of the distal pin, close to the fetlock joint. This modified transfixation pin casting technique was associated with good pin longevity and could reduce the risk of secondary pin hole fractures and pin loosening. © Copyright 2013 by The American College of Veterinary Surgeons.

  6. Impregnation of a glass fibre roving with a polypropylene melt in a pin assisted process

    NARCIS (Netherlands)

    Gaymans, R.J.; Wevers, E.

    1998-01-01

    The impregnation of a glass fibre bundle with a polypropylene (PP) melt is studied with a pin assisted process. A fibre is pulled over a pin, which is positioned in a chamber filled with a melt. The melt is at atmospheric pressure. The impregnation rate is studied as a function of size of the pin,

  7. Distribution of Endogenous NO Regulates Early Gravitropic Response and PIN2 Localization in Arabidopsis Roots

    Directory of Open Access Journals (Sweden)

    Ramiro París

    2018-04-01

    Full Text Available High-resolution and automated image analysis of individual roots demonstrated that endogenous nitric oxide (NO contribute significantly to gravitropism of Arabidopsis roots. Lowering of endogenous NO concentrations strongly reduced and even reversed gravitropism, resulting in upward bending, without affecting root growth rate. Notably, the asymmetric accumulation of NO along the upper and lower sides of roots correlated with a positive gravitropic response. Detection of NO by the specific DAF-FM DA fluorescent probe revealed that NO was higher at the lower side of horizontally-oriented roots returning to initial values 2 h after the onset of gravistimulation. We demonstrate that NO promotes plasma membrane re-localization of PIN2 in epidermal cells, which is required during the early root gravitropic response. The dynamic and asymmetric localization of both auxin and NO is critical to regulate auxin polar transport during gravitropism. Our results collectively suggest that, although auxin and NO crosstalk occurs at different levels of regulation, they converge in the regulation of PIN2 membrane trafficking in gravistimulated roots, supporting the notion that a temporally and spatially coordinated network of signal molecules could participate in the early phases of auxin polar transport during gravitropism.

  8. Pinning centres and enhancement of critical current density in YBCO doped with Pr, Ca and Ni

    Energy Technology Data Exchange (ETDEWEB)

    Huhtinen, H [Wihuri Physical Laboratory, University of Turku, FIN-20014 Turku (Finland); Awana, V P S [National Physical Laboratory, Dr K S Krishnan Road, New Delhi-110012 (India); Gupta, Anurag [National Physical Laboratory, Dr K S Krishnan Road, New Delhi-110012 (India); Kishan, Hari [National Physical Laboratory, Dr K S Krishnan Road, New Delhi-110012 (India); Laiho, R [Wihuri Physical Laboratory, University of Turku, FIN-20014 Turku (Finland); Narlikar, A V [Wihuri Physical Laboratory, University of Turku, FIN-20014 Turku (Finland)

    2007-09-15

    Substitutional studies have been carried out on sintered bulk samples of YBCO to determine the effect of doping it with Pr, Ca (at Y site) and Ni (at Cu site) in small concentrations on the formation of effective pinning centres for j{sub c} enhancement. The results show Pr and Ca substitutions to be far more effective than Ni substitution. The former two give rise to formation of rows of oxygen vacancies with pronounced strain fields in CuO{sub 2} planes where superconductivity resides. The defects thus formed seem to be analogous to arrays of normal nanodots in CuO{sub 2} planes which are expected to have strong intragrain pinning interactions with pancake vortices of CuO{sub 2} planes forming the mixed state structure. Both these substitutions tend to marginalize the adverse effects of grain boundaries. The superconducting volume fraction of the pristine sample is significantly raised by both these substitutions. These special features are, however, absent with Ni substitution. This paper brings out the importance of Pr substitution in significantly enhancing j{sub c}(B)

  9. Resistive transition of superconducting-wire networks. Influence of pinning and fluctuations

    International Nuclear Information System (INIS)

    Giroud, M.; Buisson, O.; Wang, Y.Y.; Pannetier, B.; Mailly, D.

    1992-01-01

    The authors studied the resistive transition of several 2-D superconducting-wire networks of various coupling strengths, which they characterize in terms of the Kosterlitz-Thouless transition temperature and the ratio ξ/a of the coherence length to the array period. In the extreme strong-coupling limit where the mesh size is of the order of the zero-temperature coherence length, the superconducting behavior is well described by the mean-field properties of the superconducting wave function. Extending to 2-D array, the 1-D phase-slippage model explains the dissipative regime observed above the Ginzburg-Landau depairing critical current. On the other hand, when the coupling is weak, phase fluctuations below the Ginzburg-Landau transition and vortex depinning dominate the resistive behavior. An activated dissipation is observed even below the depairing critical current. Results obtained in this regime for critical temperature, magnetoresistance, or critical current versus temperature, and magnetic field are shown; their periodic oscillations are discussed in terms of depinning of vortices on the array. A simple periodic pinning potential for a vortex in a wire network is calculated, and compared with the case of pinning in Josephson junction arrays. It is shown that this model explains qualitatively the experimental results observed for small ξ/a

  10. The doxastic shear pin: delusions as errors of learning and memory.

    Science.gov (United States)

    Fineberg, S K; Corlett, P R

    2016-01-01

    We reconsider delusions in terms of a "doxastic shear pin", a mechanism that errs so as to prevent the destruction of the machine (brain) and permit continued function (in an attenuated capacity). Delusions may disable flexible (but energetically expensive) inference. With each recall, delusions may be reinforced further and rendered resistant to contradiction. We aim to respond to deficit accounts of delusions - that delusions are only a problem without any benefit - by considering delusion formation and maintenance in terms of predictive coding. We posit that brains conform to a simple computational principle: to minimize prediction error (the mismatch between prior top-down expectation and current bottom-up input) across hierarchies of brain regions and psychological representation. Recent data suggest that delusions may form in the absence of constraining top-down expectations. Then, once formed, they become new priors that motivate other beliefs, perceptions, and actions by providing strong (sometimes overriding) top-down expectation. We argue that delusions form when the shear-pin breaks, permitting continued engagement with an overwhelming world, and ongoing function in the face of paralyzing difficulty. This crucial role should not be ignored when we treat delusions: we need to consider how a person will function in the world without them..

  11. Flux-line-cutting losses in type-II superconductors

    International Nuclear Information System (INIS)

    Clem, J.R.

    1982-01-01

    Energy dissipation associated with flux-line cutting (intersection and cross-joining of adjacent nonparallel vortices) is considered theoretically. The flux-line-cutting contribution to the dissipation per unit volume, arising from mutual annihilation of transverse magnetic flux, is identified as J/sub parallel/xE/sub parallel/, where J/sub parallel/ and E/sub parallel/ are the components of the current density and the electric field parallel to the magnetic induction. The dynamical behavior of the magnetic structure at the flux-line-cutting threshold is shown to be governed by a special critical-state model similar to that proposed by previous authors. The resulting flux-line-cutting critical-state model, characterized in planar geometry by a parallel critical current density J/sub c/parallel or a critical angle gradient k/sub c/, is used to calculate predicted hysteretic ac flux-line-cutting losses in type-II superconductors in which the flux pinning is weak. The relation of the theory to previous experiments is discussed

  12. Magnetic flux trapping in superconducting niobium

    CERN Document Server

    Benvenuti, Cristoforo; Campisi, I E; Darriulat, Pierre; Durand, C; Peck, M A; Russo, R; Valente, A M

    1997-01-01

    In a systematic study of the RF response of superconducting niobium cavities operated in their fundamental TM010 mode at 1.5 GHz, magnetic flux trapping has been used as a tool to diagnose the presenc e of pinning centres. In addition to bulk niobium cavities the study covers copper cavities, the inner walls of which are coated with 1.5 µm thick niobium films grown by magnetron sputtering in a nobl e gas atmosphere. The use of different gases (Xe, Kr, Ar and Ne) or gas mixtures has made it possible to vary the concentration of noble gas atoms in the films. Film contamination is characterised by an electron mean free path l calculated from the results of systematic measurements of the penetration depth at T = 0 K, l0, and from RRR measurements made on samples prepared under similar conditions as the cavity films.

  13. Performance test of Si PIN photodiode line scanner for thermal neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Totsuka, Daisuke, E-mail: totsuka@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Nihon Kessho Kogaku Co., Ltd., 810-5 Nobe-cho Tatebayashi, Gunma 374-0047 (Japan); Yanagida, Takayuki [New Industry Creation Hatchery Center (NICHe) 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Fukuda, Kentaro; Kawaguchi, Noriaki [Tokuyama Corp., 3 Shibuya Shibuya-ku, Tokyo 150-8383 (Japan); Fujimoto, Yutaka [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Pejchal, Jan [Institute of Physics AS CR, Cukrovarnicka 10, Prague 6, 162-53 (Czech Republic); Yokota, Yuui [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Yoshikawa, Akira [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); New Industry Creation Hatchery Center (NICHe) 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan)

    2011-12-11

    Thermal neutron imaging using Si PIN photodiode line scanner and Eu-doped LiCaAlF{sub 6} crystal scintillator has been developed. The pixel dimensions of photodiode are 1.18 mm (width) Multiplication-Sign 3.8 mm (length) with 0.4 mm gap and the module has 192 channels in linear array. The emission peaks of Eu-doped LiCaAlF{sub 6} after thermal neutron excitation are placed at 370 and 590 nm, and the corresponding photon sensitivities of photodiode are 0.04 and 0.34 A/W, respectively. Polished scintillator blocks with a size of 1.18 mm (width) Multiplication-Sign 3.8 mm (length) Multiplication-Sign 5.0 mm (thickness) were wrapped by several layers of Teflon tapes as a reflector and optically coupled to the photodiodes by silicone grease. JRR-3 MUSASI beam line emitting 13.5 meV thermal neutrons with the flux of 8 Multiplication-Sign 10{sup 5} n/cm{sup 2} s was used for the imaging test. As a subject for imaging, a Cd plate was moved at the speed of 50 mm/s perpendicular to the thermal neutron beam. Analog integration time was set to be 416.6 {mu}s, then signals were converted by a delta-sigma A/D converter. After the image processing, we successfully obtained moving Cd plate image under thermal neutron irradiation using PIN photodiode line scanner coupled with Eu-doped LiCaAlF{sub 6} scintillator.

  14. Performance test of Si PIN photodiode line scanner for thermal neutron detection

    International Nuclear Information System (INIS)

    Totsuka, Daisuke; Yanagida, Takayuki; Fukuda, Kentaro; Kawaguchi, Noriaki; Fujimoto, Yutaka; Pejchal, Jan; Yokota, Yuui; Yoshikawa, Akira

    2011-01-01

    Thermal neutron imaging using Si PIN photodiode line scanner and Eu-doped LiCaAlF 6 crystal scintillator has been developed. The pixel dimensions of photodiode are 1.18 mm (width)×3.8 mm (length) with 0.4 mm gap and the module has 192 channels in linear array. The emission peaks of Eu-doped LiCaAlF 6 after thermal neutron excitation are placed at 370 and 590 nm, and the corresponding photon sensitivities of photodiode are 0.04 and 0.34 A/W, respectively. Polished scintillator blocks with a size of 1.18 mm (width)×3.8 mm (length)×5.0 mm (thickness) were wrapped by several layers of Teflon tapes as a reflector and optically coupled to the photodiodes by silicone grease. JRR-3 MUSASI beam line emitting 13.5 meV thermal neutrons with the flux of 8×10 5 n/cm 2 s was used for the imaging test. As a subject for imaging, a Cd plate was moved at the speed of 50 mm/s perpendicular to the thermal neutron beam. Analog integration time was set to be 416.6 μs, then signals were converted by a delta-sigma A/D converter. After the image processing, we successfully obtained moving Cd plate image under thermal neutron irradiation using PIN photodiode line scanner coupled with Eu-doped LiCaAlF 6 scintillator.

  15. Clustering of Emerging Flux

    Science.gov (United States)

    Ruzmaikin, A.

    1997-01-01

    Observations show that newly emerging flux tends to appear on the Solar surface at sites where there is flux already. This results in clustering of solar activity. Standard dynamo theories do not predict this effect.

  16. The prolyl isomerase Pin1 increases β-cell proliferation and enhances insulin secretion.

    Science.gov (United States)

    Nakatsu, Yusuke; Mori, Keiichi; Matsunaga, Yasuka; Yamamotoya, Takeshi; Ueda, Koji; Inoue, Yuki; Mitsuzaki-Miyoshi, Keiko; Sakoda, Hideyuki; Fujishiro, Midori; Yamaguchi, Suguru; Kushiyama, Akifumi; Ono, Hiraku; Ishihara, Hisamitsu; Asano, Tomoichiro

    2017-07-14

    The prolyl isomerase Pin1 binds to the phosphorylated Ser/Thr-Pro motif of target proteins and enhances their cis-trans conversion. This report is the first to show that Pin1 expression in pancreatic β cells is markedly elevated by high-fat diet feeding and in ob/ob mice. To elucidate the role of Pin1 in pancreatic β cells, we generated β-cell-specific Pin1 KO (βPin1 KO) mice. These mutant mice showed exacerbation of glucose intolerance but had normal insulin sensitivity. We identified two independent factors underlying impaired insulin secretion in the βPin1 KO mice. Pin1 enhanced pancreatic β-cell proliferation, as indicated by a reduced β-cell mass in βPin1 KO mice compared with control mice. Moreover, a diet high in fat and sucrose failed to increase pancreatic β-cell growth in the βPin1 KO mice, an observation to which up-regulation of the cell cycle protein cyclin D appeared to contribute. The other role of Pin1 was to activate the insulin-secretory step: Pin1 KO β cells showed impairments in glucose- and KCl-induced elevation of the intracellular Ca 2+ concentration and insulin secretion. We also identified salt-inducible kinase 2 (SIK2) as a Pin1-binding protein that affected the regulation of Ca 2+ influx and found Pin1 to enhance SIK2 kinase activity, resulting in a decrease in p35 protein, a negative regulator of Ca 2+ influx. Taken together, our observations demonstrate critical roles of Pin1 in pancreatic β cells and that Pin1 both promotes β-cell proliferation and activates insulin secretion. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Dependence of J c on pinning center morphology: An explanation of record J c observed for discontinuous columnar pinning of vortices

    International Nuclear Information System (INIS)

    Weinstein, R.; Gandini, A.; Parks, D.; Sawh, R.; Mayes, B.

    2006-01-01

    An experimental study of defects caused by ion irradiation has proven that very discontinuous multiple-in-line-damage results in much higher J c than continuous columnar pinning centers. This is contrary to conventional wisdom. We develop a first approximation to a theory relating J c to the morphology of pinning centers. Qualitative agreement with experiment is achieved. Conclusions indicate the relative importance of pinning potential, percolation, and critical temperature for various morphologies. Results suggest the leading importance of pinning, compared to texture, weak links and oxygenation in achievement of the goal of high J c especially in large grain HTS

  18. Report on fabrication of pin components for fuel fabrication in FUJI project (Co-operation in the research and development of advanced sphere-pac fuel among PSI, JNC, and NRG)

    International Nuclear Information System (INIS)

    Suzuki, Masahiro; Hinai, Hiroshi; Shigetome, Yoshiaki; Kono, Shusaku; Matsuzaki, Masaaki

    2003-03-01

    Japan Nuclear Cycle Development Institute (JNC) has conducted the co-operation concerning vibro-packed fuels with Paul Scherrer Institut (PSI) in Switzerland and Nuclear Research and consultancy Group (NRG) in the Netherlands. The project 'Research and Development of advanced Sphere-pac Fuel' is called FUJI (FUel irradiations for JNC and PSI) Project. In this project, three types of fuels that are sphere-pac fuels, vipac fuels, and pellet fuels will be irradiated in the High Flux Reactor (HFR) to compare their performance. Based on the drawing which has been agreed among three parties, fabrication of the pin components and welding of the upper and lower connection end plugs were performed in accordance with ISO9001 in JNC. This report describes data of the fabricated pin components, results of welding qualification tests, and quality assurance of the welded components. The fabrication of pin components was successfully completed and they were delivered to PSI in October 2002. (author)

  19. Thermal performance of fresh mixed-oxide fuel in a fast flux LMR [liquid metal reactor

    International Nuclear Information System (INIS)

    Ethridge, J.L.; Baker, R.B.

    1985-01-01

    A test was designed and irradiated to provide power-to-melt (heat generation rate necessary to initiate centerline fuel melting) data for fresh mixed-oxide UO 2 -PuO 2 fuel irradiated in a fast neutron flux under prototypic liquid metal reactor (LMR) conditions. The fuel pin parameters were selected to envelope allowable fabrication ranges and address mass production of LMR fuel using sintered-to-size techniques. The test included fuel pins with variations in fabrication technique, pellet density, fuel-to-cladding gap, Pu concentration, and fuel oxygen-to-metal ratios. The resulting data base has reestablished the expected power-to-melt in mixed-oxide fuels during initial reactor startup when the fuel temperatures are expected to be the highest. Calibration of heat transfer models of fuel pin performance codes with these data are providing more accurate capability for predicting steady-state thermal behavior of current and future mixed-oxide LMR fuels

  20. Broad Temperature Pinning Study of 15 mol.% Zr-Added (Gd, Y)-Ba-Cu-O MOCVD Coated Conductors

    Energy Technology Data Exchange (ETDEWEB)

    Xu, AX; Khatri, N; Liu, YH; Majkic, G; Galstyan, E; Selvamanickam, V; Chen, YM; Lei, CH; Abraimov, D; Hu, XB; Jaroszynski, J; Larbalestier, D

    2015-06-01

    BaZrO3 (BZO) nanocolumns have long been shown to be very effective for raising the pinning force F-p of REBa2Cu3Ox (REBCO, where RE = rare earth) films at high temperatures and recently at low temperatures too. We have successfully incorporated a high density of BZO nanorods into metal organic chemical vapor deposited (MOCVD) REBCO coated conductors via Zr addition. We found that, compared to the 7.5% Zr-added coated conductor, dense BZO nanorod arrays in the 15% Zr-added conductor are effective over the whole temperature range from 77 K down to 4.2 K. We attribute the substantially enhanced J(c) at 30 K to the weak uncorrelated pinning as well as the strong correlated pinning. Meanwhile, by tripling the REBCO layer thickness to similar to 2.8 mu m, the engineering critical current density J(e) at 30 K exceeds J(e) of optimized Nb-Ti wires at 4.2 K.

  1. Pin1 promotes production of Alzheimer's amyloid β from β-cleaved amyloid precursor protein

    International Nuclear Information System (INIS)

    Akiyama, Hirotada; Shin, Ryong-Woon; Uchida, Chiyoko; Kitamoto, Tetsuyuki; Uchida, Takafumi

    2005-01-01

    Here we show that prolyl isomerase Pin1 is involved in the Aβ production central to the pathogenesis of Alzheimer's disease. Enzyme immunoassay of brains of the Pin1-deficient mice revealed that production of Aβ40 and Aβ42 was lower than that of the wild-type mice, indicating that Pin1 promotes Aβ production in the brain. GST-Pin1 pull-down and immunoprecipitation assay revealed that Pin1 binds phosphorylated Thr668-Pro of C99. In the Pin1 -/- MEF transfected with C99, Pin1 co-transfection enhanced the levels of Aβ40 and Aβ42 compared to that without Pin1 co-transfection. In COS7 cells transfected with C99, Pin1 co-transfection enhanced the generation of Aβ40 and Aβ42, and reduced the expression level of C99, facilitating the C99 turnover. Thus, Pin1 interacts with C99 and promotes its γ-cleavage, generating Aβ40 and Aβ42. Further, GSK3 inhibitor lithium blocked Pin1 binding to C99 by decreasing Thr668 phosphorylation and attenuated Aβ generation, explaining the inhibitory effect of lithium on Aβ generation

  2. Clinical and histomorphometrical study on titanium dioxide-coated external fixation pins.

    Science.gov (United States)

    Koseki, Hironobu; Asahara, Tomohiko; Shida, Takayuki; Yoda, Itaru; Horiuchi, Hidehiko; Baba, Koumei; Osaki, Makoto

    2013-01-01

    Pin site infection is the most common and significant complication of external fixation. In this work, the efficacy of pins coated with titanium dioxide (TiO(2)) for inhibition of infection was compared with that of stainless steel control pins in an in vivo study. Pins contaminated with an identifiable Staphylococcus aureus strain were inserted into femoral bone in a rat model and exposed to ultraviolet A light for 30 minutes. On day 14, the animals were sacrificed and the bone and soft tissue around the pin were retrieved. The clinical findings and histological findings were evaluated in 60 samples. Clinical signs of infection were present in 76.7% of untreated pins, but in only 36.7% of TiO(2)-coated pins. The histological bone infection score and planimetric rate of occupation for bacterial colonies and neutrophils in the TiO(2)-coated pin group were lower than those in the control group. The bone-implant contact ratio of the TiO(2)-coated pin group was significantly higher (71.4%) than in the control pin group (58.2%). The TiO(2) was successful in decreasing infection both clinically and histomorphometrically. The photocatalytic bactericidal effect of TiO(2) is thought to be useful for inhibiting pin site infection after external fixation.

  3. Investigation into Z-Pin Reinforced Composite Skin/Stiffener Debond under Monotonic and Cyclic Bending

    Science.gov (United States)

    Zhang, Xiangyang; Li, Yong; Van Hoa, Suong; Xiao, Jun; Chu, Qiyi

    2018-02-01

    Skin/stiffener debonding has been a longstanding concern for the users of stiffened composite panels in long-term service. Z-pinning technology is an emerging solution to reinforce the composite assembly joints. This work experimentally characterizes the progressive debonding of Z-pinned skin/stiffener interface with the skin under static bend loading. The three-stage failure process is identified as: flange edge debonding, pin/laminate debonding, and ultimate structural failure. Three different distribution patterns were compared in terms of the static debonding properties revealed the affirmative fact that locating pins in high normal stress regions, that is close to the flange edges in skin/stiffener structures, is more beneficial to utilize the full potential of Z-pinning reinforcement. The unit strip FE model was developed and demonstrated effective to analysis the effect of Z-pin distribution on the ultimate debond load. On the other hand, the evolution of fatigue cracks at Z-pinned skin/flange interface was investigated with a series of displacement-controlled fatigue bending tests and microscopic observations. Results show that Z-pinning postpones crack initiations at low displacement levels, and the remarkable crack-arresting function of pins enables the structure a prolonged fatigue life. However, pins become less effective when the maximum displacement exceeds the crack initiation level due to gradually pullout of pins.

  4. Evaluation of new radiolucent polymer headholder pins for use in intraoperative computed tomography.

    Science.gov (United States)

    Ardeshiri, Ardeshir; Radina, Christian; Edlauer, Martin; Ardeshiri, Ardavan; Riepertinger, Alfred; Nerlich, Andreas; Tonn, Jörg-Christian; Winkler, Peter A

    2009-12-01

    With the introduction of intraoperative CT (iCT) scanning, neurosurgeons can now obtain images of the brain during surgery, offering the possibility of intraoperative resection control and monitoring of potential intraoperative complications. The combination of iCT with neuronavigation makes it possible to update the reference scans intraoperatively when necessary. However, the headholder pins normally used for iCT scanning still show artifacts. In the present study, new polymer pins, producing nearly no artifacts in laboratory tests, are compared with the usual pins with regard to their mechanical and artifact behavior to evaluate their potential use in the clinical routine. Pins made of different materials (titanium, Macor, silicon nitride, zirconium oxide, sapphire, polyetheretherketone, and polyparaphenylene copolymer) were used for the fixation of 10 cadaveric heads. Special force sensors measured the fixation pressure of the pins, and histological analysis revealed the penetration depth. Computed tomography scans of a head phantom, fixed with the different pins, were obtained to reveal artifact behavior. All pins were biocompatible. Pins did not differ significantly in fixation pressures and mechanical behavior. Penetration depths were comparable (maximum 1.4 mm) and did not cause opening of the diploe. Polymer pins made of polyparaphenylene showed the best results in artifact behavior in CT scans. The authors' results demonstrate that the new polymer pins are comparable in their mechanical behavior to the usual pins but superior in artifact behavior. Therefore, their use in the clinical routine of iCT scanning will be beneficial for the surgeon.

  5. Study of the Radiation-Hardness of VCSEL and PIN

    CERN Document Server

    Gan, K K; Fernando, W; Kagan, H P; Kass, R D; Lebbai, M R M; Merritt, H; Moore, J R; Nagarkar, A; Rizatdinova, F; Skubic, P L; Smith, D S; Strang, M

    2009-01-01

    The silicon trackers of the ATLAS experiment at the Large Hadron Collider (LHC) at CERN (Geneva) use optical links for data transmission. An upgrade of the trackers is planned for the Super LHC (SLHC), an upgraded LHC with ten times higher luminosity. We study the radiation-hardness of VCSELs (Vertical-Cavity Surface-Emitting Laser) and GaAs and silicon PINs using 24 GeV/c protons at CERN for possible application in the data transmission upgrade. The optical power of VCSEL arrays decreases significantly after the irradiation but can be partially annealed with high drive currents. The responsivities of the PIN diodes also decrease significantly after irradiation, but can be recovered by operating at higher bias voltage. This provides a simple mechanism to recover from the radiation damage.

  6. Polarization of concave domains by traveling wave pinning.

    Directory of Open Access Journals (Sweden)

    Slawomir Bialecki

    Full Text Available Pattern formation is one of the most fundamental yet puzzling phenomena in physics and biology. We propose that traveling front pinning into concave portions of the boundary of 3-dimensional domains can serve as a generic gradient-maintaining mechanism. Such a mechanism of domain polarization arises even for scalar bistable reaction-diffusion equations, and, depending on geometry, a number of stationary fronts may be formed leading to complex spatial patterns. The main advantage of the pinning mechanism, with respect to the Turing bifurcation, is that it allows for maintaining gradients in the specific regions of the domain. By linking the instant domain shape with the spatial pattern, the mechanism can be responsible for cellular polarization and differentiation.

  7. Performance of refractory alloy-clad fuel pins

    International Nuclear Information System (INIS)

    Dutt, D.S.; Cox, C.M.; Millhollen, M.K.

    1984-12-01

    This paper discusses objectives and basic design of two fuel-cladding tests being conducted in support of SP-100 technology development. Two of the current space nuclear power concepts use conventional pin type designs, where a coolant removes the heat from the core and transports it to an out-of-core energy conversion system. An extensive irradiation testing program was conducted in the 1950's and 1960's to develop fuel pins for space nuclear reactors. The program emphasized refractory metal clad uranium nitride (UN), uranium carbide (UC), uranium oxide (UO 2 ), and metal matrix fuels (UCZr and BeO-UO 2 ). Based on this earlier work, studies presented here show that UN and UO 2 fuels in conjunction with several refractory metal cladding materials demonstrated high potential for meeting space reactor requirements and that UC could serve as an alternative but higher risk fuel

  8. Turbine blade and non-integral platform with pin attachment

    Science.gov (United States)

    Campbell, Christian X; Eng, Darryl; Marra, John J

    2015-01-27

    Platforms (36, 38) span between turbine blades (23, 24, 25) on a disk (32). Each platform may be individually mounted to the disk by a pin attachment (42). Each platform (36) may have a rotationally rearward edge portion (50) that underlies a forward portion (45) of the adjacent platform (38). This limits centrifugal bending of the rearward portion of the platform, and provides coolant sealing. The rotationally forward edge (44A, 44B) of the platform overlies a seal element (51) on the pressure side (28) of the forwardly adjacent blade, and does not underlie a shelf on that blade. The pin attachment allows radial mounting of each platform onto the disk via tilting (60) of the platform during mounting to provide mounting clearance for the rotationally rearward edge portion (50). This facilitates quick platform replacement without blade removal.

  9. Exponential synchronization of complex delayed dynamical networks via pinning periodically intermittent control

    Energy Technology Data Exchange (ETDEWEB)

    Cai Shuiming, E-mail: caishuiming2008@yahoo.com.c [Department of Mathematics, Shanghai University, Shanghai 200444 (China); Institute of System Biology, Shanghai University, Shanghai 200444 (China); Hao Junjun [Institute of System Biology, Shanghai University, Shanghai 200444 (China); He, Qinbin [Department of Mathematics, Taizhou University, Linhai 317000 (China); Institute of System Biology, Shanghai University, Shanghai 200444 (China); Liu Zengrong, E-mail: zrongliu@126.co [Department of Mathematics, Shanghai University, Shanghai 200444 (China) and Institute of System Biology, Shanghai University, Shanghai 200444 (China)

    2011-05-09

    The problem of synchronization for a class of complex delayed dynamical networks via pinning periodically intermittent control is considered in this Letter. Some novel and useful exponential synchronization criteria are obtained by utilizing the methods which are different from the techniques employed in the existing works, and the derived results are less conservative. Especially, the traditional assumptions on control width and time delays are released in our results. Moreover, a pinning scheme deciding what nodes should be chosen as pinned candidates and how many nodes are needed to be pinned for a fixed coupling strength is provided. A Barabasi-Albert network example is finally given to illustrate the effectiveness of the theoretical results. - Highlights: Pinning control problem of complex networks via intermittent control is investigated. The traditional assumptions on control width and time delays are removed. A scheme deciding what nodes should be chosen as pinned candidates is proposed. A scheme deciding how many nodes are needed to be pinned is provided.

  10. Investigation of silicon PIN-detector for laser pulse detection

    OpenAIRE

    Chau, Sam

    2004-01-01

    This report has been written at SAAB Bofors Dynamics (SBD) AB in Gothenburg at the department of optronic systems. In military observation operations, a target to hit is chosen by illumination of a laser designator. From the targetpoint laser radiation is reflected on a detector that helps identify the target. The detector is a semiconductor PIN-type that has been investigated in a laboratory environment together with a specially designed laser source. The detector is a photodiode and using p...

  11. Prevention of pin tract infection with titanium-copper alloys.

    Science.gov (United States)

    Shirai, Toshiharu; Tsuchiya, Hiroyuki; Shimizu, Tohru; Ohtani, Kaori; Zen, Yo; Tomita, Katsuro

    2009-10-01

    The most frequent complication in external fixation is pin tract infection. To reduce the incidence of implant-associated infection, many published reports have looked at preventing bacterial adhesion by treating the pin surface. This study aimed to evaluate the antibacterial activity of a Titanium-Copper (Ti-Cu) alloy on implant infection, and to determine the potential use of the Ti-Cu alloy as a biomaterial. Two forms of Ti-Cu alloys were synthesized: one with 1% Cu and the other with 5% Cu. For analyzing infectious behavior, the implants were exposed to Staphylococcus aureus and Escherichia coli. The reaction of pathogens to the Ti-Cu alloys was compared with their reaction to stainless steel and pure titanium as controls. Both Ti-Cu alloys evidently inhibited colonization by both bacteria. Conversely, cytocompatibility studies were performed using fibroblasts and colony formation on the metals was assessed by counting the number of colonies. Ti-1% Cu alloy showed no difference in the number of colonies compared with the control. External fixator pins made of Ti-Cu alloys were evaluated in a rabbit model. The tissue-implant interactions were analyzed for the presence of infection, inflammatory changes and osteoid-formation. Ti-1% Cu alloy significantly inhibited inflammation and infection, and had excellent osteoid-formation. Copper blood levels were measured before surgery and at 14 days postoperatively. Preoperative and postoperative blood copper values were not statistically different. Overall, it was concluded that Ti-Cu alloys have antimicrobial activity and substantially reduce the incidence of pin tract infection. Ti-1% Cu alloy shows particular promise as a biomaterial. (c) 2009 Wiley Periodicals, Inc.

  12. Examination of failed tube guide pins in operational conditions

    International Nuclear Information System (INIS)

    Cattant, F.; Pichon, C.

    1985-01-01

    The examinations at the High Activity Laboratory in Chinon (France) of the guide tube pins taken from power plants showed, that the pieces have cracks induced by stress corrosion in primary medium, that any metallurgical state initially considered hit and that cracks are at the level of the first inferior thread, of shank-flange hollow and at the level of the flexible branches [fr

  13. Anticipating WPS PIN Vulnerability to Secure Wireless Network

    Directory of Open Access Journals (Sweden)

    Indra Dwi Rianto

    2013-12-01

    Full Text Available WiFi Protected Setup (WPS is a standardized function supported by numerous vendors of wireless routers and access point to help set up connection to a wireless local area network. It is designed to simplify the set up and generally enabled by default. Due to design flaw, the WPS or QSS PIN is susceptible to a brute forceattack. In this paper, we test the security vulnerability occurred, evaluate the performance and give recommendations to anticipate the attack.

  14. X-ray measurement with Pin type semiconductor detectors

    International Nuclear Information System (INIS)

    Ramirez J, F.J.

    1999-01-01

    Here are presented the experimental results of the applications of Pin type radiation detectors developed in a National Institute of Nuclear Research (ININ) project, in the measurement of low energy gamma and X-rays. The applications were oriented mainly toward the Medical Physics area. It is planned other applications which are in process of implementation inside the National Institute of Nuclear Research in Mexico. (Author)

  15. PinK - a TCL/TK based database interface to ADAMO and DAD

    International Nuclear Information System (INIS)

    Ackerstaff, K.; Funk, M.A.; Dueren, M.; Ferstl, M.; Wander, W.; Welch, P.

    1996-01-01

    PinK is a TCL/TK extension developed initially for the HERMES experiment at HERA/DESY. Like other HEP experiments, HERMES needs a highly structured database to cope with the complexity and amount of data being handled. HERMES uses the ADAMO Entity Relationship database concept together with the DAD package which extends the use of ADAMO towards a distributed database with flexible, fast I/O and time dependent data handling. With a large and complex time dependent database and many programs accessing it, there is a strong demand for a flexible common user interface. PINK incorporates the functionality of ADAMO and DAD providing an Object Oriented interface to the database. It can be used as an interactive command line, as well as graphical user interface to access and manipulate data on the databases serves and files. (author)

  16. Calibration of the E Si detector in a DE-E telescope with a ^212Pb pin source

    Science.gov (United States)

    Chan, Ka Pang

    2012-10-01

    In nuclear physics experiments, telescopes composed of two or more large area silicon strip detectors are used to identify charged particles. To use the energy loss method for particle identification, a thin (˜0.065mm) silicon detector (DE) is mounted in front of a thicker E detector (˜1.5 mm). The DE Si detector can be calibrated with 8.785, 6.778, 6.288, 5.685 and 5.423 MeV alpha particles emitted from a ^228Th source. However, this method cannot be used to calibrate the E detector as the alpha particles cannot penetrate the front DE detector. We have developed a method to calibrate the E detector by inserting a small irradiated dowel pin between the two Si detectors. The pin source is electroplated with ^212Pb nuclei which emit alpha particles with 8.785 MeV, 6.090 and 6.051 MeV. Insertion of the dowel pin is designed and guided so that the head of the pin lies near the center of the detector at a distance of 2.72 mm away from the surface of the E detector. In addition to providing two strong alpha peaks for calibrations, the close distance and high pixilation of the E detector allows accurate determination of the front dead layer of the E Si strip detector. This technique has been implemented successfully in calibrating the E Si detectors in the NSCL High Resolution Array (HiRA) consisting of 20 closely pack DE-E-CsI telescopes.

  17. End-threaded intramedullary positive profile screw ended self-tapping pin (Admit pin - A cost-effective novel implant for fixing canine long bone fractures

    Directory of Open Access Journals (Sweden)

    Mitin Chanana

    2018-02-01

    Full Text Available Aim: The current study was undertaken to evaluate the clinical efficacy of end-threaded intramedullary pinning for management of various long bone fractures in canines. Materials and Methods: This study was conducted in two phases, managing 25 client-owned dogs presented with different fractures. The technique of application of end-threaded intramedullary pinning in long bone fractures was initially standardized in 6 clinical patients presented with long bone fractures. In this phase, end-threaded pins of different profiles, i.e., positive and negative, were used as the internal fixation technique. On the basis of results obtained from standardization phase, 19 client-owned dogs clinically presented with different fractures were implanted with end-threaded intramedullary positive profile screw ended self-tapping pin in the clinical application phase. Results: The patients, allocated randomly in two groups, when evaluated postoperatively revealed slight pin migration in Group-I (negative profile, which resulted in disruption of callus site causing delayed union in one case and large callus formation in other two cases whereas no pin migration was observed in Group-II (positive profile. Other observations in Group-I was reduced muscle girth and delayed healing time as compared to Group-II. In clinical application, phase 21st and 42nd day post-operative radiographic follow-up revealed no pin migration in any of the cases, and there was no bone shortening or fragment collapse in end-threaded intramedullary positive profile screw ended self-tapping pin. Conclusion: The end-threaded intramedullary positive profile screw ended self-tapping pin used for fixation of long bone fractures in canines can resist pin migration, pin breakage, and all loads acting on the bone, i.e., compression, tension, bending, rotation, and shearing to an extent with no post-operative complications.

  18. Contact and Non-contact Measurements of Grinding Pins

    Directory of Open Access Journals (Sweden)

    Magdziak Marek

    2015-01-01

    Full Text Available The paper presents the results of contact and non-contact measurements of external profiles of selected grinding pins. The measurements were conducted in order to choose the appropriate measuring technique in the case of the considered measurement task. In the case of contact measurements the coordinate measuring machine ACCURA II was applied. The used coordinate measuring machine was equipped with the contact scanning probe VAST XT and the Calypso inspection software. Contact coordinate measurements were performed by using of different measurement strategies. The applied strategies included different scanning velocities and distances between measured points. Non-contact measurements were conducted by means of the tool presetter produced by the Mahr company. On the basis of gained results the guidelines concerning measurements of grinding pins were formulated. The measurements of analyzed grinding pins performed by means of the non-contact measuring system are characterized by higher reproducibility than the contact measurements. The low reproducibility of contact measurements may be connected with the inaccuracy of the selected coordinate measuring machine and the measuring probe, the measurement parameters and environmental conditions in the laboratory where the coordinate measuring machine is located. Moreover, the paper presents the possible application of results of conducted investigations. The results of non-contact measurements can be used in the simulation studies of grinding processes. The simulations may reduce the costs of machining processes.

  19. Strongly Correlated Topological Insulators

    Science.gov (United States)

    2016-02-03

    Strongly Correlated Topological Insulators In the past year, the grant was used for work in the field of topological phases, with emphasis on finding...surface of topological insulators. In the past 3 years, we have started a new direction, that of fractional topological insulators. These are materials...in which a topologically nontrivial quasi-flat band is fractionally filled and then subject to strong interactions. The views, opinions and/or

  20. Strong Cosmic Censorship

    Science.gov (United States)

    Isenberg, James

    2017-01-01

    The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

  1. Vortex dynamics in supraconductors in the presence of anisotropic pinning

    International Nuclear Information System (INIS)

    Soroka, O.K.

    2004-01-01

    Vortex dynamics in two different classes of superconductors with anisotropic unidirected pinning sites was experimentally investigated by magnetoresistivity measurements: YBCO-films with unidirected twins and Nb-films deposited on faceted Al 2 O 3 substrate surfaces. For the interpretation of the experimental results a theoretical model based on the Fokker-Planck equation was used. It was proved by X-ray measurements that YBCO films prepared on (001) NdGaO 3 substrates exhibit only one twin orientation in contrast to YBCO films grown on (100) SrTiO 3 substrates. The magnetoresistivity measurements of the YBCO films with unidirected twin boundaries revealed the existence of two new magnetoresistivity components, which is a characteristic feature of a guided vortex motion: an odd longitudinal component with respect to the magnetic field sign reversal and an even transversal component. However, due to the small coherence length in YBCO and the higher density of point-like defects comparing to high-quality YBCO single crystals, the strength of the isotropic point pinning was comparable with the strength of the pinning produced by twins. This smeared out all e ects caused by the pinning anisotropy. The behaviour of the odd longitudinal component was found to be independent of the transport current direction with respect to the twin planes. The magnetoresistivity measurements of faceted Nb films demonstrated the appearance of an odd longitudinal and even transversal component of the magnetoresistivity. The temperature and magnetic field dependences of all relevant magnetoresistivity components were measured. The angles between the average vortex velocity vector and the transport current direction calculated from the experimental data for the different transport current orientations with respect to the facet ridges showed that the vortices moved indeed along the facet ridges. An anomalous Hall effect, i.e. a sign change of the odd transversal magnetoresistivity, has been

  2. X-ray measurement with Pin type semiconductor detectors; Medicion de rayos X con detectores de semiconductor tipo PIN

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez J, F.J. [Instituto Nacional de Investigaciones Nucleares, Departamento de Electronica, C.P. 52045 Salazar, Estado de Mexico (Mexico)

    2000-07-01

    Here are presented the experimental results of the applications of Pin type radiation detectors developed in a National Institute of Nuclear Research (ININ) project, in the measurement of low energy gamma and X-rays. The applications were oriented mainly toward the Medical Physics area. It is planned other applications which are in process of implementation inside the National Institute of Nuclear Research in Mexico. (Author)

  3. Cell plate-restricted association of Arabidopsis dynamin related proteins and PIN auxin efflux carriers is required for PIN endocytic trafficking during cytokinesis.

    NARCIS (Netherlands)

    Mravec, J.; Petrasek, J.; Li, N.; Boeren, J.A.; Karlova, R.B.; Kitakura, S.; Naramoto, S.; Nodzynski, T.; Dhonukshe, P.B.; Vries, de S.C.; Zazimalova, E.; Friml, J.

    2011-01-01

    The polarized transport of the phytohormone auxin [1], which is crucial for the regulation of different stages of plant development [ [2] and [3] ], depends on the asymmetric plasma membrane distribution of the PIN-FORMED (PIN) auxin efflux carriers [4 A. Vieten, M. Sauer, P.B. Brewer and J. Friml,

  4. Establishing the need for an engineering standard for agricultural hitch pins.

    Science.gov (United States)

    Deboy, G R; Knapp, W M; Field, W E; Krutz, G W; Corum, C L

    2012-04-01

    Documented incidents have occurred in which failure or unintentional disengagement of agricultural hitch pins has contributed to property damage and personal injury. An examination of current hitch pin use on a convenience sample of farm operations in Indiana revealed a variety of non-standard, worn and damaged, and inappropriately sized hitch pins in use. Informal interviews with the farm operators confirmed that hitch pin misuse, failure, or disengagement is a relatively widespread problem that remains largely unaddressed. On-site observations also suggested a low use of hitch pin retaining devices or safety chains. A review of prior research revealed that little attention has been given to this problem, and currently no documentation allows for an estimate of the frequency or severity of losses associated with hitch pin misuse, failure, or disengagement. No specific engineering standards were found that directly applied to the design, appropriate selection, or loading capacity of agricultural hitch pins. Major suppliers of replacement hitch pins currently provide little or no information on matching hitch pin size to intended applications, and most replacement hitch pins examined were of foreign origin, with the overwhelming majority imported from China or India. These replacement hitch pins provided no specifications other than diameter, length, and, in some cases, labeling that indicated that the pins had been "heat treated. " Testing of a sample of 11 commercially available replacement hitch pins found variation along the length of the pin shaft and between individual pins in surface hardness, a potential predictor of pin failure. Examination of 17 commercially available replacement pins also revealed a variety of identifiers used to describe pin composition and fabrication methods, e.g., "heat treated." None of the pins examined provided any specifications on loading capacity. It was therefore concluded that there is a need to develop an agricultural hitch

  5. Postirradiation examinations of fuel pins from the GCFR F-1 series of mixed-oxide fuel pins at 5.5 at. % burnup

    International Nuclear Information System (INIS)

    Strain, R.V.; Johnson, C.E.

    1978-05-01

    Postirradiation examinations were performed on five fuel pins from the Gas-Cooled Fast-Breeder Reactor F-1 experiment irradiated in EBR-II to a peak burnup of approximately 5.5 at. %. These encapsulated fuel pins were irradiated at peak-power linear ratings from approximately 13 to 15 kW/ft and peak cladding inside diameter temperatures from approximately 625 to 760 0 C. The maximum diametral change that occurred during irradiation was 0.2% ΔD/D 0 . The maximum fuel-cladding chemical interaction depth was 2.6 mils in fuel pin G-1 and 1 mil or less in the other three pins examined destructively. Significant migration of the volatile fission products occurred axially to the fuel-blanket interfaces. Teh postirradiation examination data indicate that fuel melted at the inner surface of the annular fuel pellets in the two highest power rating fuel pins, but little axial movement of fuel occurred

  6. Thermal and stress analyses in thermoelectric generator with tapered and rectangular pin configurations

    International Nuclear Information System (INIS)

    Yilbas, Bekir Sami; Akhtar, S.S.; Sahin, A.Z.

    2016-01-01

    Thermal stress developed in thermoelectric generators is critical for long service applications. High temperature gradients, due to a large temperature difference across the junctions, causes excessive stress levels developed in the device pins and electrodes at the interfaces. In the present study, a thermoelectric generator with horizontal pin configuration is considered and thermal stress analysis in the device is presented. Ceramic wafer is considered to resemble the high temperature plate and copper electrodes are introduced at the pin junctions to reduce the electrical resistance between the pins and the high and low temperature junction plates during the operation. Finite element code is used to simulate temperature and stress fields in the thermoelectric generator. In the simulations, convection and radiation losses from the thermoelectric pins are considered and bismuth telluride pin material with and without tapering is incorporated. It is found that von Mises stress attains high values at the interface between the hot and cold junctions and the copper electrodes. Thermal stress developed in tapered pin configuration attains lower values than that of rectangular pin cross-section. - Highlights: • Different cold junction temperatures improves thermoelectric generator performance. • von Mises stress remains high across copper electrodes and hot junction ceramics. • von Mises stress reduces along pin length towards cold junction. • Pin tapering lowers stress levels in thermoelectric generator.

  7. In vivo corrosion behavior of gold-plated versus titanium dental retention pins.

    Science.gov (United States)

    Palaghias, G; Eliades, G; Vougiouklakis, G

    1992-02-01

    Two types of titanium dental retention pins and a gold-plated stainless steel pin were tested for their in vivo corrosion behavior. Six paired samples of titanium and gold-plated pins were placed in box preparations of 12 periodontally involved premolars. Half of the samples were restored with a high copper admixed type amalgam while the rest were restored with a BisGMA-POCl2 bonding resin and a hybrid visible light-cured composite resin. After 3 months in vivo, the teeth were extracted, and the pins were removed and examined with an electron microprobe. The surface of the titanium pins was found to be smooth and without defects. Only traces of Ca and P could be identified from dentin. The gold-plated pins demonstrated cracks and pores, especially at the outer part of the serrations, resulting in disruption of the electroplated film. Traces of Hg, Sn, Cu, S, Zn, Ca, K, Cl, P, and S were detected at the gold-plated pin/amalgam interface, while Cl and P were found at the gold-plated pin/composite resin interface. The in vivo corrosion resistance of the titanium pins was found to be superior to that of the gold-plated stainless steel pins.

  8. Excessive Cellular S-nitrosothiol Impairs Endocytosis of Auxin Efflux Transporter PIN2

    Directory of Open Access Journals (Sweden)

    Min Ni

    2017-11-01

    Full Text Available S-nitrosoglutathione reductase (GSNOR1 is the key enzyme that regulates cellular levels of S-nitrosylation across kingdoms. We have previously reported that loss of GSNOR1 resulted in impaired auxin signaling and compromised auxin transport in Arabidopsis, leading to the auxin-related morphological phenotypes. However, the molecular mechanism underpinning the compromised auxin transport in gsnor1-3 mutant is still unknown. Endocytosis of plasma-membrane (PM-localized efflux PIN proteins play critical roles in auxin transport. Therefore, we investigate whether loss of GSNOR1 function has any effects on the endocytosis of PIN-FORMED (PIN proteins. It was found that the endocytosis of either the endogenous PIN2 or the transgenically expressed PIN2-GFP was compromised in the root cells of gsnor1-3 seedlings relative to Col-0. The internalization of PM-associated PIN2 or PIN2-GFP into Brefeldin A (BFA bodies was significantly reduced in gsnor1-3 upon BFA treatment in a manner independent of de novo protein synthesis. In addition, the exogenously applied GSNO not only compromised the endocytosis of PIN2-GFP but also inhibited the root elongation in a concentration-dependent manner. Taken together, our results indicate that, besides the reduced PIN2 level, one or more compromised components in the endocytosis pathway could account for the reduced endocytosis of PIN2 in gsnor1-3.

  9. Monoaxial external fixation of the calcaneus: An anatomical study assessing the safety of monoaxial pin insertion.

    Science.gov (United States)

    Thomson, Callum M; Esparon, Tom; Rea, Paul M; Jamal, Bilal

    2016-10-01

    The use of external fixation for intra-articular calcaneal fractures is increasing in popularity. Studies have shown fine wire and monoaxial external fixation to be a viable surgical alternative to more invasive methods of open reduction and internal fixation of the calcaneus. However, there is an absence of literature that quantifies the risk of pin insertion for monoaxial fixation. This study aimed to determine the safety of inserting monoaxial pins within the calcaneus to house the Orthofix Calcaneal Mini-Fixator. Five formalin embalmed cadaveric ankle and lower leg specimens were inserted with six monoaxial pins. Careful dissection then revealed the presence of the tendons of peroneus longus and brevis, the sural nerve and the small saphenous vein in relation to these pins. Measurements from each pin to each of these structures were made as the structures transected lines drawn from each pin to two palpable bony landmarks: the inferior tip of the lateral malleolus and the posterosuperior calcaneus. In doing this, the risk posed by each pin could be evaluated. We found that two particular pins, those used to hold the articular surface of the subtalar joint in a reduced position, posed a larger risk of injury to surrounding structures than the remaining pins. These findings therefore suggest that monoaxial fixation of the calcaneus using a six pin approach is a relatively safe method of rectifying calcaneal fractures and thus may serve as a welcome alternative to other methods of calcaneal fixation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Analysis and results of a hydrogen-moderated isotope production assembly in the Fast Flux Test Facility

    International Nuclear Information System (INIS)

    Wootan, D.W.; Rawlins, J.A.; Carter, L.L.; Brager, H.R.; Schenter, R.E.

    1989-01-01

    This paper reports on a cobalt test assembly containing yttrium hydride pins for neutron moderation irradiated in the Fast Flux Test Facility (FFTF) during cycle 9A for 137.7 equivalent full-power days at a power level of 291 MW. The 36 test pins consisted of a batch of 32 pins containing cobalt metal used to produce 60 Co and a set of four pins with europium oxide to produce 153 Gd, a radioisotope used in detection of the bone disease osteoporosis. Postirradiation examination of the cobalt pins determined the 60 Co production to be predictable to an accuracy of ∼ 5%. The measured 60 Co spatially distributed concentrations were within 20% of the calculated concentrations. The assembly average 60 Co measured activity was 4% less than the calculated value. The europium oxide pins were gamma scanned for the europium isotopes 152 Eu and 154 Eu to an absolute accuracy of ≅ 10%. The measured europium radioisotope and 153 Gd concentrations were within 20% of calculated values. The hydride assembly performed well and is an excellent vehicle for many FFTF isotope production applications. The results also demonstrate the accuracy of the calculational methods developed by the Westinghouse Hanford Company for predicting isotope production rates in this type of assembly

  11. Strong Arcwise Connectedness

    OpenAIRE

    Espinoza, Benjamin; Gartside, Paul; Kovan-Bakan, Merve; Mamatelashvili, Ana

    2012-01-01

    A space is `n-strong arc connected' (n-sac) if for any n points in the space there is an arc in the space visiting them in order. A space is omega-strong arc connected (omega-sac) if it is n-sac for all n. We study these properties in finite graphs, regular continua, and rational continua. There are no 4-sac graphs, but there are 3-sac graphs and graphs which are 2-sac but not 3-sac. For every n there is an n-sac regular continuum, but no regular continuum is omega-sac. There is an omega-sac ...

  12. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2009-01-01

    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally......'s scenarios have some valuable future or admitted that killing them is not seriously morally wrong. Finally, if "valuable future" is interpreted as referring to objective standards, one ends up with implausible and unpalatable moral claims....

  13. Spectroscopy and coherent manipulation of single and coupled flux qubits

    International Nuclear Information System (INIS)

    Wu Yu-Lin; Deng Hui; Huang Ke-Qiang; Tian Ye; Yu Hai-Feng; Xue Guang-Ming; Jin Yi-Rong; Li Jie; Zhao Shi-Ping; Zheng Dong-Ning

    2013-01-01

    Measurements of three-junction flux qubits, both single flux qubits and coupled flux qubits, using a coupled direct current superconducting quantum interference device (dc-SQUID) for readout are reported. The measurement procedure is described in detail. We performed spectroscopy measurements and coherent manipulations of the qubit states on a single flux qubit, demonstrating quantum energy levels and Rabi oscillations, with Rabi oscillation decay time T Rabi = 78 ns and energy relaxation time T 1 = 315 ns. We found that the value of T Rabi depends strongly on the mutual inductance between the qubit and the magnetic coil. We also performed spectroscopy measurements on inductively coupled flux qubits. (general)

  14. Compact neutron flux monitor

    International Nuclear Information System (INIS)

    Madhavi, V.; Phatak, P.R.; Bahadur, C.; Bayala, A.K.; Jakati, R.K.; Sathian, V.

    2003-01-01

    Full text: A compact size neutron flux monitor has been developed incorporating standard boards developed for smart radiation monitors. The sensitivity of the monitors is 0.4cps/nV. It has been tested up to 2075 nV flux with standard neutron sources. It shows convincing results even in high flux areas like 6m away from the accelerator in RMC (Parel) for 106/107 nV. These monitors have a focal and remote display, alarm function with potential free contacts for centralized control and additional provision of connectivity via RS485/Ethernet. This paper describes the construction, working and results of the above flux monitor

  15. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.

    1992-01-01

    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  16. Evidence of pinning crossover and the role of twin boundaries in the peak effect in FeSeTe iron based superconductor

    Science.gov (United States)

    Galluzzi, A.; Buchkov, K.; Tomov, V.; Nazarova, E.; Leo, A.; Grimaldi, G.; Nigro, A.; Pace, S.; Polichetti, M.

    2018-01-01

    The correlation between the appearance of a peak effect in the critical current of a superconducting material and the presence of twin boundaries, involved in a crossover between different pinning regimes, is investigated by means of dc magnetic measurements on a FeSe0.5Te0.5 crystal. In particular, by analyzing the temperature dependence of the critical current density J c(T) for different magnetic fields H, a crossover from a weak pinning regime to a strong pinning regime has been revealed. The analysis shows that this crossover can be ascribed to the presence of twin boundary defects inside the sample, and can be associated to the onset of the peak effect and interpreted as the start of the vortex dynamic processes responsible for the increase of J c with the field. On the basis of the information extracted by our analysis, a plausible dynamic scenario involving the contribution of the different pinning regimes depending on the applied field has been described, and the relative H(T) vortex phase diagram has been determined. Moreover, in our description, the peak in the J c(H) curve corresponds to the end of the processes leading to the peak effect and it is confirmed to be related to the transition from an elastic to a plastic deformation regime in the vortex lattice.

  17. Three-dimensional vortex pinning by nano-precipitates in a Sm-doped YBa{sub 2}Cu{sub 3}O{sub 7-x} coated conductor

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z [University of Wisconsin-Madison, Madison, WI 53706 (United States); Feldmann, D M [University of Wisconsin-Madison, Madison, WI 53706 (United States); Song, X [University of Wisconsin-Madison, Madison, WI 53706 (United States); Kim, S I [University of Wisconsin-Madison, Madison, WI 53706 (United States); Gurevich, A [University of Wisconsin-Madison, Madison, WI 53706 (United States); Reeves, J L [SuperPower Incorporated, 450 Duane Avenue, Schenectady, NY 12304 (United States); Xie, Y Y [SuperPower Incorporated, 450 Duane Avenue, Schenectady, NY 12304 (United States); Selvamanickam, V [SuperPower Incorporated, 450 Duane Avenue, Schenectady, NY 12304 (United States); Larbalestier, D C [University of Wisconsin-Madison, Madison, WI 53706 (United States)

    2007-09-15

    We report on the thickness and angular dependence of the critical current density J{sub c}(H,{theta}), the irreversibility field H{sup irr}, and the bulk pinning force F{sub p}(H) of a metal-organic chemical vapour deposition (MOCVD) grown YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) coated conductor, which contains {approx}17 vol% of {approx}10 nm sized (Y,Sm){sub 2}O{sub 3} precipitates with an average spacing of {approx}10-15 nm. Some surface porosity and amorphous second-phase particles on the scale of {approx}0.5-1 {mu}m appear to reduce the current-carrying cross-section, which controls the magnitude of J{sub c} but not the vortex pinning. We observed an enhanced H{sup irr}{approx}9 T at 77 K along the c-axis which, like the shape of J{sub c}(H) and F{sub p}(H), was independent of thickness as the sample was milled down to {approx}0.16 {mu}m. Angular-dependent measurements of J{sub c} showed the usual excess vortex pinning along the c-axis and along the ab-plane, but with a background that could only be fitted with an unusually small anisotropy parameter of 3, which, like the high H{sup irr} and the thickness-independent shape of F{sub p}(H), we ascribe to strong vortex pinning centre interactions. Together, these measurements show very different behaviour from most pulsed-laser-deposited films, which exhibit strong thickness-dependent properties. We ascribe the present different results to the dense array of small, insulating precipitates, which act as strong pinning centres and produce strong three-dimensional (3D) vortex pinning, because their separation of 10-15 nm is always much smaller than the film thickness.

  18. Fractional Matching Effect due to Pinning of the Vortex Lattice by an Array of Magnetic Dots

    Science.gov (United States)

    Stoll, O. M.; Montero, M. I.; Jönsson-Åkerman, B. J.; Schuller, Ivan K.

    2001-03-01

    We have investigated the pinning of magnetic flux quanta by rectangular arrays of nanoscaled magnetic dots. We measured the resistivity vs. magnetic field characteristics using a high magnetic field resolution of up to 0.1 G over the full field range ( 2 kG to 2 kG). By this we the appearance of minima at half and third integer values of the matching field. It is well known that a reconfiguration of the vortex lattice from a rectangular to a square type geometry occurs in rectangular arrays of magnetic dots when the magnetic field is increased over a threshold value H_r. If we lower the magnetic field after crossing H_r, we find that some of the minima at the full integer matching field are missing. This hysteretic behavior occurs only when Hr is exceeded before the subsequent decrease of the magnetic field. We present the experimental results and discuss preliminary models for the explanation of these observations. This work was supported by the grants NSF and DOE. Two of us acknowledge postdoctoral fellowships by the DAAD (Deutscher Akademischer Austauschdienst) (O.M.S.) and the Secretaria De Estado De Educacion Y Universidades (M.I.M.) respectively.

  19. Progress on DEMO blanket attachment concept with keys and pins

    International Nuclear Information System (INIS)

    Vizvary, Zsolt; Iglesias, Daniel; Cooper, David; Crowe, Robert; Riccardo, Valeria

    2015-01-01

    Highlights: • DEMO blanket attachment system with keys and pins (without using bolts). • Blanket segments are preloaded by progressively designed springs. • Blanket back plate flexibility has a major impact on spring design. • Mechanical analysis of other components indicates no unresolvable issues. • Thermal analysis indicates acceptable temperatures for the support system. - Abstract: The blanket attachment has to cope with gravity, thermal and electromagnetic loads, also it has to be installed and serviced by remote handling. Pre-stressed components suffer from stress relaxation in irradiated environments such as DEMO. To circumvent this problem pre-stressed component should be either avoided or shielded, and where possible keys and pins should be used. This strategy has been proposed for the DEMO multi-module segments (MMS). The blanket segments are held by two tapered keys each, designed to allow thermal expansions while providing contact with the vacuum vessel and to resist the poloidal and radial moments the latter being dominant at 9.1 MNm inboard and 15 MNm outboard. On the top of the blanket segment there is a pin which provides vertical support. At the bottom another vertical support has to lock them in position after installation and manage the pre-load on the segments. The pre-load is required to deal with the electromagnetic loads during disruption. This is provided by a set of springs, which require shielding as they are preloaded. These are sized to cope with the force (3 MN inboard, 1.4 MN outboard) due to halo currents and the toroidal moment which can reverse. Calculations show that the flexibility of the blanket segment itself plays a significant role in defining the required support system. The blanket segment acts as a preloaded spring and it has to be part of the attachment design as well.

  20. Pinning Properties of PLD (NdxSmxGd1−2x)Ba2Cu3O7−δ Thin films

    DEFF Research Database (Denmark)

    Li, Xiaofen; Grivel, Jean-Claude; Yue, Zhao

    2012-01-01

    that the accommodation field at low temperature is increased due to the substitution. However, the decay of the self field critical current density and less effective pinning at higher temperature make the high level substituted films less attractive compared with the low level substituted film from the application......The self field critical current density, flux relaxation rate and accommodation field is studied in ternary rare earth (RE) barium cuprate thin films made by PLD on STO, with RE=Nd, Sm and Gd. By systematically changing the substitution level of Nd and Sm in GdBCO films, we found...

  1. GaN-based PIN alpha particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Wang Guo [Peking University, Shenzhen Graduate School, Guangdong Shenzhen 518055 (China); Peking University, Beijing, 100871 (China); Fu Kai; Yao Changsheng [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Science, Jiangsu Suzhou 215123 (China); Su Dan; Zhang Guoguang [China Institute of Atomic Energy, Beijing 102413 (China); Wang Jinyan [Peking University, Beijing, 100871 (China); Lu Min, E-mail: mlu2006@sinano.ac.cn [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Science, Jiangsu Suzhou 215123 (China)

    2012-01-21

    GaN-based PIN alpha particle detectors are studied in this article. The electrical properties of detectors have been investigated, such as current-voltage (I-V) and capacitance-voltage (C-V). The reverse current of all detectors is in nA range applied at 30 V, which is suitable for detector operation. The charge collection efficiency (CCE) is measured to be approximately 80% but the energy resolution is calculated to be about 40% mostly because the intrinsic layer is not sufficiently thick enough.

  2. Analyzing the use of pins in safety bearings

    DEFF Research Database (Denmark)

    da Fonseca, Cesar A. L. L.; Weber, Hans I.; Fleischer, Philip F.

    2015-01-01

    A new concept for safety bearings is analyzed: useful in emergency situations, it shall protect the bearing from destruction by the use of pins which impact with a disc, both capable of good energy dissipation. Results of work in progress are presented by validating partial stages......, the variation of energy content of the disc after each contact is considered. Actually, the validation of the clamped-free rotor is done. The main goal is to design an automatic system with the capability of changing the gap when necessary in order to avoid the rotor colliding with the inner part of the bearing....

  3. Current Kink and Capacitance Frequency Dispersion in Silicon PIN Photodiodes

    Science.gov (United States)

    Guo, Xia; Feng, Yajie; Liu, Qiaoli; Wang, Huaqiang; Li, Chong; Hu, Zonghai; He, Xiaoying

    2017-09-01

    Silicon PIN photodiodes in the visible wavelength range have been widely applied in aerospace, defense, security, medical, and scientific instruments because of their high sensitivity and low cost. In this paper, the phenomena of the current kink and the capacitance frequency dispersion are observed. Contamination at the p-type Ohmic contact interface is proposed to explain the current kink effect and capacitance frequency dispersion, according to the temperature-dependent I-V measurement results in which trap-assisted tunneling process demonstrated.

  4. FFTF fuel pin design procedure verification for transient operation

    International Nuclear Information System (INIS)

    Baars, R.E.

    1975-05-01

    The FFTF design procedures for evaluating fuel pin transient performance are briefly reviewed, and data where available are compared with design procedure predictions. Specifically, burst conditions derived from Fuel Cladding Transient Tester (FCTT) tests and from ANL loss-of-flow tests are compared with burst pressures computed using the design procedure upon which the cladding integrity limit was based. Failure times are predicted using the design procedure for evaluation of rapid reactivity insertion accidents, for five unterminated TREAT experiments in which well characterized fuel failures were deliberately incurred. (U.S.)

  5. Etat des lieux et perspectives du pin sylvestre en Wallonie

    OpenAIRE

    Thibaut, K.; Colson, Vincent; Lecomte, H.; Claessens, Hugues

    2007-01-01

    Si le pin sylvestre fut l’un des pionniers de la reforestation de nos contrées, l’engouement qu’il suscita au XIXe siècle semble aujourd’hui bien retombé. À travers l’analyse de la ressource disponible et d’une rapide enquête auprès des cantonnements de la DNF, l’article propose un état des lieux de cette essence et discute de ses perspectives dans le contexte actuel.

  6. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin

    2011-01-01

    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

  7. An automated alpha scanner for estimating plutonium contamination levels on FBTR fuel pin

    International Nuclear Information System (INIS)

    Bagul, D.G.; Sharma, V.P.; Benadikar, S.V.; Karnani, N.K.; Kamath, K.V.

    1995-01-01

    An automated alpha scanner has been developed for estimating plutonium contamination on SS clad fuel pins fabricated in Radiometallurgy Division for Fast Breeder Test Reactor (FBTR). The unit can detect as low as 1% of the allowed contamination limit for the fuel pin. Because of automation, large number of pins can be systematically scanned for Pu contamination with minimum radiation exposure to the operator. (author). 3 refs., 1 fig., 1 tab

  8. Objects of agreement: Placing pins to progress collaborative activity in custom dressmaking

    DEFF Research Database (Denmark)

    Nevile, Maurice Richard

    2018-01-01

    ’s body, including lifting and folding the fabric, and gesture and move around the dancer. Analyses focus on moments when the dressmaker places a pin into the dress fabric. I suggest that placing a pin provides a physical and visual realization of talk and embodied conduct directed towards agreement...... on suggested changes to the dress. Placing a pin therefore objectifies participation and progress in collaborative activity for dressmaking. The data language is Danish....

  9. Influences on ARC Stability in Welding of Aluminum Pin-Structures

    Science.gov (United States)

    Wittwer, Lukas; Jank, Nasrin; Bećirović, Almedin; Waldhör, Andreas; Enzinger, Norbert

    Pin structures offer an innovative way of joining dissimilar materials such as metals and plastics based on an additional geometric link. Therefore pins are placed on a metal sheet substrate by use of a special arc welding technique called cold metal transfer (CMT), developed by Fronius International. The key element of the CMT process is moving the wire back and forth during the welding process. This controlled movement combined with proper welding parameters allows a defined shaping of the pin.

  10. [Treatment of complex hand injuries by stable osteosynthesis using a "multiple pinning" technique].

    Science.gov (United States)

    Le Nen, D; Hu, W; Genestet, M; Liot, M; Tran Quan, J; Dos Remédios, C; Mener, G

    2004-04-01

    The multiple pinning technique has been reported by the authors as an effective method for the treatment of comminuted osteo-articular fractures of the digits. This procedure can be performed rapidly, offers good stability and thereby allows early post-operative physiotherapy. The aim of this type of management is to offer the patient recovery of thumb to digit pinch by restoring two functional joints (MCP, PIP) or at least one functional joint (MCP), particularly as far as the radial digits are concerned. After performing reduction, very small diameter pins are introduced and the bone fragments are reconstructed like a puzzle. The very small calibre of the pins allows multiple pinning and simultaneously permits them to be easily orientated. The pins being multiple, and parallel or diverging are responsible for the stability of the construct. The ends of the pins are either bent over or more frequently, just cut flush with the surface of the bone. Comminuted fractures, even the most severe, respond very nicely to this management. The multiple pinning technique offers remarkable stability, allowing early post-operative physiotherapy. This technique is particularly effective when faced with the difficulties of treating open fractures of the metacarpals and phalanges. Moreover, this technique avoids performing an extensive skin incision. The stability of this multiple pinning technique could be related to the following factors: the shortness of the pins offering more rigidity and less flexibility, the proper fixation of the pins within the cortical bone, especially in the diaphysis and the large number of pins offering more strength. The disadvantage of this technique is the possibility of pin migration.

  11. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

  12. Solar Magnetic Flux Ropes

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... The most probable initial magnetic configuration of a CME is a flux rope consisting of twisted field lines which fill the whole volume of a dark coronal cavity. The flux ropes can be in stable equilibrium in the coronal magnetic field for weeks and even months, but suddenly they lose their stability and erupt with ...

  13. The PIN1 family gene PvPIN1 is involved in auxin-dependent root emergence and tillering in switchgrass

    Directory of Open Access Journals (Sweden)

    Kaijie Xu

    2016-03-01

    Full Text Available Abstract Switchgrass (Panicum virgatum L.; family Poaceae is a warm-season C4 perennial grass. Tillering plays an important role in determining the morphology of aboveground parts and the final biomass yield of switchgrass. Auxin distribution in plants can affect a variety of important growth and developmental processes, including the regulation of shoot and root branching, plant resistance and biological yield. Auxin transport and gradients in plants are mediated by influx and efflux carriers. PvPIN1, a switchgrass PIN1-like gene that is involved in regulating polar transport, is a putative auxin efflux carrier. Neighbor-joining analysis using sequences deposited in NCBI databases showed that the PvPIN1gene belongs to the PIN1 family and is evolutionarily closer to the Oryza sativa japonica group. Tiller emergence and development was significantly promoted in plants subjected toPvPIN1 RNA interference (RNAi, which yielded a phenotype similar to that of wild-type plants treated with the auxin transport inhibitor TIBA (2,3,5-triiodobenzoic acid. A transgenic approach that inducedPvPIN1 gene overexpression or suppression altered tiller number and the shoot/root ratio. These data suggest that PvPIN1plays an important role in auxin-dependent adventitious root emergence and tillering.

  14. Strong pinning in very fast grown reactive co-evaporated GdBa2Cu3O7 coated conductors

    Directory of Open Access Journals (Sweden)

    J. L. MacManus-Driscoll

    2014-08-01

    Full Text Available We report on compositional tuning to create excellent field-performance of Jc in “self-doped,” GdBa2Cu3O7−y (GdBCO coated conductors grown by ultrafast reactive co-evaporation. In order to give excess liquid and Gd2O3, the overall compositions were all Ba-poor and Cu-rich compared to GdBCO. The precise composition was found to be critical to the current carrying performance. The most copper-rich composition had an optimum self-field Jc of 3.2 MA cm−2. A more Gd-rich composition had the best in-field performance because of the formation of low coherence, splayed Gd2O3 nanoparticles, giving Jc (77 K, 1 T of over 1 MA cm−2 and Jc (77 K, 5 T of over 0.1 MA cm−2.

  15. Effects of Pin1 loss in HdhQ111 knock-in mice

    Directory of Open Access Journals (Sweden)

    Elena eAgostoni

    2016-05-01

    Full Text Available Huntington’s disease (HD is a fatal, dominantly inherited, neurodegenerative disorder due to a pathological expansion of the CAG repeat in the coding region of the HTT gene. In the quest for understanding the molecular basis of neurodegeneration, we have previously demonstrated that the prolyl isomerase Pin1 plays a crucial role in mediating p53-dependent apoptosis triggered by mutant huntingtin (mHtt in vitro. To assess the effects of the lack of Pin1 in vivo, we have bred Pin1 knock-out mice with HdhQ111 knock-in mice, a genetically precise model of HD. We show that Pin1 genetic ablation modifies a portion of HdhQ111 phenotypes in a time-dependent fashion. As an early event, Pin1 activity reduces the DNA damage response. In midlife mice, by taking advantage of next-generation sequencing technology, we show that Pin1 activity modulates a portion of the alterations triggered by mHtt, extending the role of Pin1 to two additional HdhQ111 phenotypes: the unbalance in the synthesis/concentration of hormones, as well as the alteration of Wnt/β-catenin signaling. In aging animals, Pin1 significantly increases the number of mHtt-positive nuclear inclusions while it reduces gliosis. In summary, this work provides further support for a role of Pin1 in HD pathogenesis.

  16. Peptidyl Prolyl Isomerase PIN1 Directly Binds to and Stabilizes Hypoxia-Inducible Factor-1α.

    Directory of Open Access Journals (Sweden)

    Hyeong-Jun Han

    Full Text Available Peptidyl prolyl isomerase (PIN1 regulates the functional activity of a subset of phosphoproteins through binding to phosphorylated Ser/Thr-Pro motifs and subsequently isomerization of the phosphorylated bonds. Interestingly, PIN1 is overexpressed in many types of malignancies including breast, prostate, lung and colon cancers. However, its oncogenic functions have not been fully elucidated. Here, we report that PIN1 directly interacts with hypoxia-inducible factor (HIF-1α in human colon cancer (HCT116 cells. PIN1 binding to HIF-1α occurred in a phosphorylation-dependent manner. We also found that PIN1 interacted with HIF-1α at both exogenous and endogenous levels. Notably, PIN1 binding stabilized the HIF-1α protein, given that their levels were significantly increased under hypoxic conditions. The stabilization of HIF-1α resulted in increased transcriptional activity, consequently upregulating expression of vascular endothelial growth factor, a major contributor to angiogenesis. Silencing of PIN1 or pharmacologic inhibition of its activity abrogated the angiogenesis. By utilizing a bioluminescence imaging technique, we were able to demonstrate that PIN1 inhibition dramatically reduced the tumor volume in a subcutaneous mouse xenograft model and angiogenesis as well as hypoxia-induced transcriptional activity of HIF-1α. These results suggest that PIN1 interacting with HIF-1α is a potential cancer chemopreventive and therapeutic target.

  17. Optimal Number of Fixation Pins for Dedicated Mini Jig Cutting Guides During Navigated Total Knee Arthroplasty.

    Science.gov (United States)

    D'Costa, Elliott; Sivakumar, Brahman; Tsung, Jason

    2016-12-01

    The optimal number of fixation pins for minimally invasive cutting guides in computer-navigated arthroplasty has not been determined. The authors hypothesized that more fixation pins will lead to greater mechanical stability and more accurate resections. 12 bovine knee joints were divided into three groups with differing numbers of fixation pins. The ASM [Stryker] knee navigation system was utilized to perform resections, and accuracy of alignment and posterior slope was measured. Comparison was performed between the groups to calculate average differences between predicted and actual resection with differing number of pins. The difference between actual and predicted values showed a trend toward diminishing with a greater number of fixation pins. The mean difference in coronal alignment of predicted versus actual resection was 0.75° for two fixation pins, 0.5° for three pins and 1° for four fixation pins. Similarly, the difference between posterior slope was 2.75°, 2°, and 1°, respectively. This study reveals a trend toward greater accuracy of resections with more fixation pins. Further investigation may be beneficial.

  18. Enquiry into the Topology of Plasma Membrane-Localized PIN Auxin Transport Components.

    Science.gov (United States)

    Nodzyński, Tomasz; Vanneste, Steffen; Zwiewka, Marta; Pernisová, Markéta; Hejátko, Jan; Friml, Jiří

    2016-11-07

    Auxin directs plant ontogenesis via differential accumulation within tissues depending largely on the activity of PIN proteins that mediate auxin efflux from cells and its directional cell-to-cell transport. Regardless of the developmental importance of PINs, the structure of these transporters is poorly characterized. Here, we present experimental data concerning protein topology of plasma membrane-localized PINs. Utilizing approaches based on pH-dependent quenching of fluorescent reporters combined with immunolocalization techniques, we mapped the membrane topology of PINs and further cross-validated our results using available topology modeling software. We delineated the topology of PIN1 with two transmembrane (TM) bundles of five α-helices linked by a large intracellular loop and a C-terminus positioned outside the cytoplasm. Using constraints derived from our experimental data, we also provide an updated position of helical regions generating a verisimilitude model of PIN1. Since the canonical long PINs show a high degree of conservation in TM domains and auxin transport capacity has been demonstrated for Arabidopsis representatives of this group, this empirically enhanced topological model of PIN1 will be an important starting point for further studies on PIN structure-function relationships. In addition, we have established protocols that can be used to probe the topology of other plasma membrane proteins in plants. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Research on Pin Tumbler Locks and the Characteristics of Surface Traces Formed by Unlocking Guns

    Science.gov (United States)

    Yi, Gao; Yifeng, Jin; Yanping, Bai; Hongcheng, Mei; Zhen, Xu

    2018-02-01

    In this paper, taking the structure of the pin tumbler locks and the principle of opening and closing locks as breakthrough point, we have studied the machining traces of pin tumbler components and trace characters of pin surface during normal operating. At the same time, taking the unlocking gun as an example, the paper analyzes the unlocking technology and the formation of traces, and summarizes the changing rules of the surface traces of elastic bead locks by comparing the positions and the characteristics of the traces, which provides technical support for the future study of traces of pin tumbler locks.

  20. Experimental determination of configurational entropy in a two-dimensional liquid under random pinning

    Science.gov (United States)

    Williams, Ian; Turci, Francesco; Hallett, James E.; Crowther, Peter; Cammarota, Chiara; Biroli, Giulio; Royall, C. Patrick

    2018-03-01

    A quasi two-dimensional colloidal suspension is studied under the influence of immobilisation (pinning) of a random fraction of its particles. We introduce a novel experimental method to perform random pinning and, with the support of numerical simulation, we find that increasing the pinning concentration smoothly arrests the system, with a cross-over from a regime of high mobility and high entropy to a regime of low mobility and low entropy. At the local level, we study fluctuations in area fraction and concentration of pins and map them to entropic structural signatures and local mobility, obtaining a measure for the local entropic fluctuations of the experimental system.