WorldWideScience

Sample records for local critical current

  1. Interface localization near criticality

    CERN Document Server

    Delfino, Gesualdo

    2016-01-01

    The theory of interface localization in near-critical planar systems at phase coexistence is formulated from first principles. We show that mutual delocalization of two interfaces, amounting to interfacial wetting, occurs when the bulk correlation length critical exponent $\

  2. Evaluation of global and local critical current densities in 122-type iron-based superconducting tapes

    Energy Technology Data Exchange (ETDEWEB)

    Pyon, Sunseng, E-mail: pyon@ap.t.u-tokyo.ac.jp; Mine, Akinori; Suwa, Takahiro; Tamegai, Tsuyoshi

    2016-11-15

    Highlights: • (Ba,K)Fe{sub 2}As{sub 2} superconducting pressed tapes are fabricated. • We found an intriguing anisotropy in J{sub c} determined by magnetic measurements, which is related to microcrack structures affecting the local J{sub c}. • Microcrack structures are directly observed by magneto-optical imaging technique. - Abstract: We demonstrate the fabrication of (Ba,K)Fe{sub 2}As{sub 2} superconducting pressed tapes through a powder-in-tube method using uniaxial cold pressing technique, and evaluate global and local J{sub c} by several physical measurements. We found an intriguing anisotropy in J{sub c} determined by magnetic measurements, which is related to microcrack structures affecting the local J{sub c}. The maximum J{sub c} estimated from magnetization measurements has reached ∼1.9 × 10{sup 5} A/cm{sup 2} under self-field at 4.2 K. Furthermore, microcrack structures are directly observed by magneto-optical imaging technique.

  3. Global and local critical current density in superconducting SmFeAsO{sub 1-x}F{sub x} measured by two methods

    Energy Technology Data Exchange (ETDEWEB)

    Otabe, E.S., E-mail: otabe@cse.kyutech.ac.j [Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka 820-8502 (Japan); Kiuchi, M.; Kawai, S. [Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka 820-8502 (Japan); Morita, Y.; Ge, J.; Ni, B. [Department of Life, Environment and Material Science, Fukuoka Institute of Technology, 3-30-1 Wajirohigashi, Higashi-ku, Fukuoka 811-0295 (Japan); Gao, Z.; Wang, L.; Qi, Y.; Zhang, X.; Ma, Y. [Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, P.O. Box 2703, Beijing 100190 (China)

    2009-11-01

    The critical current densities of polycrystalline bulk SmFeAsO{sub 1-x}F{sub x} prepared by the powder-in-tube (PIT) method and by a conventional solid-state reaction were investigated using the remnant magnetic moment method and Campbell's method. Two types of shielding current, corresponding to global and local critical current densities J{sub c} were observed using both measurement methods. The global and local J{sub c} were on the order of 10{sup 7} A/m{sup 2} and 10{sup 10} A/m{sup 2} at 5 K, respectively. The local J{sub c} decreased slightly with increasing magnetic field. The global J{sub c} was independent of the preparation method, while the local J{sub c} was larger for samples prepared by PIT than for those prepared by solid-state reaction.

  4. Correlation of local structure peculiarities and critical current density of 2G MOCVD YBCO tapes with BaZrO3 nanoinclusions

    Science.gov (United States)

    Menushenkov, A. P.; Ivanov, V. G.; Chepikov, V. N.; Nygaard, R. R.; Soldatenko, A. V.; Rudnev, I. A.; Osipov, M. A.; Mineev, N. A.; Kaul, A. R.; Mathon, O.; Monteseguro, V.

    2017-04-01

    We have studied the influence of BaZrO3 nanoinclusions on the local structure and critical current density of second-generation high temperature superconducting tapes based on YBa2Cu3O7-δ (YBCO) films. The films were made by metal-organic chemical vapor deposition (MOCVD). The crystal and local structure of the materials under study were analysed by x-ray diffraction and x-ray absorption spectroscopy (EXAFS + XANES). We have found that, being added at MOCVD process, Zr forms BaZrO3 nanoinclusions in YBCO matrix. The distance between Zr and the neighboring atoms is shorter than that one in a bulk crystalline BaZrO3, so we conclude that the nanoinclusions are in compressed state. The incorporation of 5 mol% BaZrO3 minimizes the static disorder of Cu-O bonds and maximizes their stiffness in YBCO. We show that the local structure peculiarities correlate well with the observed critical current behavior and consider this to be additional evidence in favor of small amounts of BaZrO3 nanoinclusions as efficient pinning centers.

  5. Enhancing superconducting critical current by randomness.

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y. L.; Thoutam, L. R.; Xiao, Z. L.; Shen, B.; Pearson, J.; Divan, R.; Ocola, L. E.; Crabtree, G. W.; Kwok, W. K.

    2016-01-11

    The key ingredient of high critical currents in a type-II superconductor is defect sites that pin vortices. Here, we demonstrate that a random pinscape, an overlooked pinning system in nanopatterned superconductors, can lead to a substantially larger critical current enhancement at high magnetic fields than an ordered array of vortex pin sites. We reveal that the better performance of a random pinscape is due to the variation of the local density of its pinning sites, which mitigates the motion of vortices. This is confirmed by achieving even higher enhancement of the critical current through a conformally mapped random pinscape, where the distribution of the local density of pinning sites is further enlarged. Our findings highlight the potential of random pinscapes in enhancing the superconducting critical currents of applied superconductors in which random pin sites of nanoscale defects emerging in the materials synthesis process or through ex-situ irradiation are the only practical choice for large-scale production. Our results may also stimulate research on effects of a random pinscape in other complementary systems such as colloidal crystals, Bose-Einstein condensates, and Luttinger liquids.

  6. Critical state model with anisotropic critical current density

    CERN Document Server

    Bhagwat, K V; Ravikumar, G

    2003-01-01

    Analytical solutions of Bean's critical state model with critical current density J sub c being anisotropic are obtained for superconducting cylindrical samples of arbitrary cross section in a parallel geometry. We present a method for calculating the flux fronts and magnetization curves. Results are presented for cylinders with elliptical cross section with a specific form of the anisotropy. We find that over a certain range of the anisotropy parameter the flux fronts have shapes similar to those for an isotropic sample. However, in general, the presence of anisotropy significantly modifies the shape of the flux fronts. The field for full flux penetration also depends on the anisotropy parameter. The method is extended to the case of anisotropic J sub c that also depends on the local field B, and magnetization hysteresis curves are presented for typical values of the anisotropy parameter for the case of |J sub c | that decreases exponentially with |B|.

  7. Enhancing critical current density of cuprate superconductors

    Science.gov (United States)

    Chaudhari, Praveen

    2015-06-16

    The present invention concerns the enhancement of critical current densities in cuprate superconductors. Such enhancement of critical current densities include using wave function symmetry and restricting movement of Abrikosov (A) vortices, Josephson (J) vortices, or Abrikosov-Josephson (A-J) vortices by using the half integer vortices associated with d-wave symmetry present in the grain boundary.

  8. Critical current densities in superconducting materials

    Indian Academy of Sciences (India)

    P Chaddah

    2003-02-01

    We discuss recent research in the area of critical current densities $(J_C)$ in superconductors. This shall cover recent work on newly discovered superconductors, as well as on the magnetic-field dependence of $J_C$.

  9. Variable-Temperature Critical-Current Measurements

    Energy Technology Data Exchange (ETDEWEB)

    L. F. Goodrich; T. C. Stauffer

    2009-05-19

    This is the final report of a three year contract that covered 09/19/2005 to 07/14/2008. We requested and received a no cost time extension for the third year, 07/15/2007 to 07/14/2008, to allow DoE to send us funds if they became available during that year. It turned out that we did not receive any funding for the third year. The following paper covers our variable-temperature critical-current measurements. We made transport critical-current (Ic) measurements on commercial multifilamentary Nb3Sn strands at temperatures (T) from 4 to 17 K and magnetic fields (H) from 0 to 14 T. One of the unique features of our measurements is that we can cover a wide range of critical currents from less than 0.1 A to over 700 A.

  10. Noncontact Measurement Of Critical Current In Superconductor

    Science.gov (United States)

    Israelsson, Ulf E.; Strayer, Donald M.

    1992-01-01

    Critical current measured indirectly via flux-compression technique. Magnetic flux compressed into gap between superconductive hollow cylinder and superconductive rod when rod inserted in hole in cylinder. Hall-effect probe measures flux density before and after compression. Method does not involve any electrical contact with superconductor. Therefore, does not cause resistive heating and consequent premature loss of superconductivity.

  11. Critical current properties in HTS tapes

    Energy Technology Data Exchange (ETDEWEB)

    Kiss, T.; Inoue, M.; Kuga, T.; Ishimaru, M.; Egashira, S.; Irie, S.; Ohta, T.; Imamura, K.; Yasunaga, M.; Takeo, M.; Matsushita, T.; Iijima, Y.; Kakimoto, K.; Saitoh, T.; Awaji, S.; Watanabe, K.; Shiohara, Y

    2003-10-15

    The author's recent studies on the critical current properties in Bi-2223 multifilamentary tapes as well as YBCO coated IBAD tapes have been reviewed. Extended electric field vs. current density (E-J) characteristics were studied over wide range of temperature, T, magnetic field, B, and angle, {theta}. Based on the analysis of statistic J{sub c} distribution and scaling, we derived an analytical expression for J as a function of E, T, B, and {theta}. This method allows us to describe and extrapolate the nonlinear E-J characteristics even in extremely low E region and/or high B region based on rather simple measurements.

  12. Critical current density: Measurements vs. reality

    Science.gov (United States)

    Pan, A. V.; Golovchanskiy, I. A.; Fedoseev, S. A.

    2013-07-01

    Different experimental techniques are employed to evaluate the critical current density (Jc), namely transport current measurements and two different magnetisation measurements forming quasi-equilibrium and dynamic critical states. Our technique-dependent results for superconducting YBa2Cu3O7 (YBCO) film and MgB2 bulk samples show an extremely high sensitivity of Jc and associated interpretations, such as irreversibility fields and Kramer plots, which lose meaning without a universal approach. We propose such approach for YBCO films based on their unique pinning features. This approach allows us to accurately recalculate the magnetic-field-dependent Jc obtained by any technique into the Jc behaviour, which would have been measured by any other method without performing the corresponding experiments. We also discovered low-frequency-dependent phenomena, governing flux dynamics, but contradicting the considered ones in the literature. The understanding of these phenomena, relevant to applications with moving superconductors, can clarify their dramatic impact on the electric-field criterion through flux diffusivity and corresponding measurements.

  13. Criticality and turbulence in a resistive magnetohydrodynamic current sheet.

    Science.gov (United States)

    Klimas, Alexander J; Uritsky, Vadim M

    2017-02-01

    Scaling properties of a two-dimensional (2d) plasma physical current-sheet simulation model involving a full set of magnetohydrodynamic (MHD) equations with current-dependent resistivity are investigated. The current sheet supports a spatial magnetic field reversal that is forced through loading of magnetic flux containing plasma at boundaries of the simulation domain. A balance is reached between loading and annihilation of the magnetic flux through reconnection at the current sheet; the transport of magnetic flux from boundaries to current sheet is realized in the form of spatiotemporal avalanches exhibiting power-law statistics of lifetimes and sizes. We identify this dynamics as self-organized criticality (SOC) by verifying an extended set of scaling laws related to both global and local properties of the current sheet (critical susceptibility, finite-size scaling of probability distributions, geometric exponents). The critical exponents obtained from this analysis suggest that the model operates in a slowly driven SOC state similar to the mean-field state of the directed stochastic sandpile model. We also investigate multiscale correlations in the velocity field and find them numerically indistinguishable from certain intermittent turbulence (IT) theories. The results provide clues on physical conditions for SOC behavior in a broad class of plasma systems with propagating instabilities, and suggest that SOC and IT may coexist in driven current sheets which occur ubiquitously in astrophysical and space plasmas.

  14. Criticality and turbulence in a resistive magnetohydrodynamic current sheet

    Science.gov (United States)

    Klimas, Alexander J.; Uritsky, Vadim M.

    2017-02-01

    Scaling properties of a two-dimensional (2d) plasma physical current-sheet simulation model involving a full set of magnetohydrodynamic (MHD) equations with current-dependent resistivity are investigated. The current sheet supports a spatial magnetic field reversal that is forced through loading of magnetic flux containing plasma at boundaries of the simulation domain. A balance is reached between loading and annihilation of the magnetic flux through reconnection at the current sheet; the transport of magnetic flux from boundaries to current sheet is realized in the form of spatiotemporal avalanches exhibiting power-law statistics of lifetimes and sizes. We identify this dynamics as self-organized criticality (SOC) by verifying an extended set of scaling laws related to both global and local properties of the current sheet (critical susceptibility, finite-size scaling of probability distributions, geometric exponents). The critical exponents obtained from this analysis suggest that the model operates in a slowly driven SOC state similar to the mean-field state of the directed stochastic sandpile model. We also investigate multiscale correlations in the velocity field and find them numerically indistinguishable from certain intermittent turbulence (IT) theories. The results provide clues on physical conditions for SOC behavior in a broad class of plasma systems with propagating instabilities, and suggest that SOC and IT may coexist in driven current sheets which occur ubiquitously in astrophysical and space plasmas.

  15. Critical Consciousness: Current Status and Future Directions

    Science.gov (United States)

    Watts, Roderick J.; Diemer, Matthew A.; Voight, Adam M.

    2011-01-01

    In this chapter, the authors consider Paulo Freire's construct of critical consciousness (CC) and why it deserves more attention in research and discourse on youth political and civic development. His approach to education and similar ideas by other scholars of liberation aims to foster a critical analysis of society--and one's status within…

  16. Critical Current in YBCO Coated Conductors in the Presence of a Macroscopic Defect (POSTPRINT)

    Science.gov (United States)

    2010-03-01

    AFRL-RZ-WP-TP-2010-2084 CRITICAL CURRENT IN YBCO COATED CONDUCTORS IN THE PRESENCE OF A MACROSCOPIC DEFECT (POSTPRINT) Milan Polak and...CRITICAL CURRENT IN YBCO COATED CONDUCTORS IN THE PRESENCE OF A MACROSCOPIC DEFECT (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c...display, or disclose the work. 14. ABSTRACT We have studied the effects of localized defects in the YBCO coated conductors on the critical current. The

  17. Magnetization of a Current-Carrying Superconducting Disk with B-Dependent Critical Current Density

    Science.gov (United States)

    Sohrabi, Mahdi; Babaei-Brojeny, Ali A.

    2010-11-01

    In the frame work of the critical state model (CSM), the magnetic response of a thin type-II superconducting disk that carries a radial transport current and is subjected to an applied magnetic field have been studied. To this end, we have studied the process of the magnetic flux-penetration. For a disk initially containing no magnetic flux but carrying a radial current, when a perpendicular magnetic field is applied, magnetic flux-penetration occurs in three stages: (1) the magnetic flux gradually penetrates from the edges of the disk until an instability occurs, (2) there is a rapid inflow of magnetic flux into the disk’s central region, which becomes resistive, and (3) magnetic flux continues to enter the disk, while persistent azimuthal currents flow in an outer annular region where the net current density is equal to J c . Also the behavior of a current-carrying disk subjected to an AC magnetic field is calculated. The magnetic flux, the current profiles and the magnetization hysteresis loops are calculated for several commonly used J c ( B) dependences. Finally, the results of the applications of the local field-dependent of the critical current density J c ( B) are compared with those obtained from the Bean model.

  18. Critical current measurement for design of HTS DC power cables

    Science.gov (United States)

    Watanabe, Hirofumi

    2017-02-01

    Critical currents of HTS DC power cables were calculated. In the calculation a relationship between critical current density and magnetic flux density proposed by Gömöry et al. [1] was used and the parameters used in the relationship were obtained by the critical current measurements with respect to the external magnetic field for a sample of the HTS tape. Numerical models of cables were composed and their critical currents were calculated, which showed the strong dependence on the arrangement of the HTS tapes in the cable. Critical current measurements of model cables assembled based on the calculations showed that the measured critical currents also depended on the arrangement of the HTS tapes strongly. The calculated results were compared with the experimental results, which showed that the experimental results agreed well with the calculated results.

  19. High Critical Current in Metal Organic Derived YBCO Films

    Science.gov (United States)

    2010-10-31

    Contract No. FA9550-07-C-0034 “High Critical Current in Metal Organic Derived YBCO Films” Final Report Prepared for: Dr. Harold...Critical Current in Metal Organic Derived YBCO Films 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT...Project focused on optimization of the Metal Organic Deposition (MOD) process for deposition thick, high critical current YBCO films for use in the

  20. Current approach to burn critical care.

    Science.gov (United States)

    Sakallioglu, A E; Haberal, M

    2007-10-01

    Burn trauma is a frequent cause of morbidity and mortality all over the world. Advancements in resuscitation, surgical tecniques, infection control and nutritional/metaolic support decreased mortality and morbidity. This article intends to review current outlines for initial treatment and resuscitation nutritional/metabolic support and wound management peculiar to burn patients.

  1. Percutaneous vertebroplasty: Current concepts and local experience

    Directory of Open Access Journals (Sweden)

    Hee Hwan

    2005-01-01

    Full Text Available With the aging population in our country, symptomatic osteoporotic compression fractures are increasingly common. Osteolytic compression fractures from spinal metastasis are also becoming more frequently seen because of the longer life expectancy from improvements in chemotherapy. Percutaneous vertebroplasty with PMMA has been shown to be an efficient procedure to treat pain due to these fractures. It is a minimally invasive procedure performed under local anesthesia and sedation. Injection of PMMA provides immediate stability when it hardens, and permits the patient to ambulate without pain. Appropriate patient selection is the key to clinical success. However, this procedure must be treated with respect, and has to be performed by physicians with the necessary training. Otherwise, increased pain, paralysis, and even death may occur from this seemingly innocuous procedure. In this article, I will deal with the background issues of osteoporotic and osteolytic vertebral compression fractures, patient selection, surgical technique, complications, and review of current literature on vertebroplasty. Key areas of development in this field include the use of kyphoplasty, defining the role of prophylactic augmentation, and improvements in biomaterials.

  2. The critical current and irreversible magnetisation in UPt 3

    Science.gov (United States)

    Kambe, S.; Huxley, A. D.; Rodière, P.; Paulsen, C.; Flouquet, J.

    1999-01-01

    We have measured the field-dependence of critical current and magnetisation in the superconducting phase of a single crystal of UPt 3. At low temperatures the critical current shows a peak below Hc2, which is also seen in measurements of the magnetic hysterisis. The onset of the peak does not coincide with the transition between the B and C superconducting phases, which is consistent with measurements of the magnetic hysterisis.

  3. Micromagnetic modeling of critical current oscillations in magnetic Josephson junctions

    Science.gov (United States)

    Golovchanskiy, I. A.; Bol'ginov, V. V.; Stolyarov, V. S.; Abramov, N. N.; Ben Hamida, A.; Emelyanova, O. V.; Stolyarov, B. S.; Kupriyanov, M. Yu.; Golubov, A. A.; Ryazanov, V. V.

    2016-12-01

    In this work we propose and explore an effective numerical approach for investigation of critical current dependence on applied magnetic field for magnetic Josephson junctions with in-plane magnetization orientation. This approach is based on micromagnetic simulation of the magnetization reversal process in the ferromagnetic layer with introduced internal magnetic stiffness and subsequent reconstruction of the critical current value using total flux or reconstructed actual phase difference distribution. The approach is flexible and shows good agreement with experimental data obtained on Josephson junctions with ferromagnetic barriers. Based on this approach we have obtained a critical current dependence on applied magnetic field for rectangular magnetic Josephson junctions with high size aspect ratio. We have shown that the rectangular magnetic Josephson junctions can be considered for application as an effective Josephson magnetic memory element with the value of critical current defined by the orientation of magnetic moment at zero magnetic field. An impact of shape magnetic anisotropy on critical current is revealed and discussed. Finally, we have considered a curling magnetic state in the ferromagnetic layer and demonstrated its impact on critical current.

  4. Controlling local currents in molecular junctions

    CERN Document Server

    Yadalam, Hari Kumar

    2016-01-01

    The effect of non-equilibrium constraints and dephasing on the circulating currents in molecular junctions are analyzed. Circulating currents are manifestations of quantum effects and can be induced either by externally applied bias or an external magnetic field through the molecular system. In symmetric Aharonov-Bohm ring, bond currents have two contributions, bias driven and magnetic field driven. We analyze the competition between these two contributions and show that, as a consequence, current through one of the branches can be completely suppressed. We then study the effect of asymmetry (as a result of chemical substitution) on the current pathways inside the molecule and study asymmetry induced circulating currents (without magnetic field) by tuning the coupling strength of the substituent (at finite bias).

  5. Current distribution and enhancement of the engineering critical current density in multifilament Bi-2223 tapes

    DEFF Research Database (Denmark)

    Wang, W.G.; Jensen, M.B.; Kindl, B.;

    2000-01-01

    The spatial distribution of the critical current density (Jc) and engineering critical current density (Je) along the tape width direction was studied by a cutting technique on Bi-2223 multifilamentary tapes. In general, an increase of Jc towards the centre of the tape was measured. We attribute...... this tendency to the stress-strain experienced in the tape during the rolling process. Jc of 50 kA/cm2 and Jeof 18 kA/cm2 was measured at the centre part (185 μm wide and 200 μm thick) of a tape cut from a 500 meters long tape (average Je of 8 kA/cm2). The low Jc of the edge part is a result of the porous...... microstructure with a great amount of secondary phases. Local variation of Jc was measured within the centre segment of the tape. This indicates the influence of other factors on Jc, such as filament shape, connectivity of the filaments, and sausaging. Enhancement of Je has been pursued in which average Je of 12...

  6. Critical current studies of a HTS rectangular coil

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Z. [Department of Engineering, University of Cambridge (United Kingdom); Chudy, M., E-mail: Michal.chudy@stuba.sk [Graduate School of Technology Management, University of Pretoria (South Africa); Institute of Power and Applied Electrical Engineering, Slovak University of Technology in Bratislava (Slovakia); Ruiz, H.S. [Department of Engineering, University of Leicester, Leicester LE1 7RH (United Kingdom); Zhang, X.; Coombs, T. [Department of Engineering, University of Cambridge (United Kingdom)

    2017-05-15

    Highlights: • Unique square pancake coil was manufactured. • Measurements in relatively high magnetic field were performed. • Different sections of the coil were characterized. • Parts of the coil which are limiting critical current were identified. - Abstract: Nowadays, superconducting high field magnets are used in numerous applications due to their superior properties. High temperature superconductors (HTS) are usually used for production of circular pancake or racetrack coils. However different geometries of HTS coils might be required for some specific applications. In this study, the HTS coil wound on a rectangular frame was fully characterized in homogeneous DC background field. The study contains measurements of critical current angular dependencies. The critical current of the entire coil and two selected strands under different magnitudes and orientations of external magnetic fields are measured. The critical regions of the coil in different angular regimes are determined. This study brings better understanding of the in- field performance of HTS coils wound on frames with right-angles.

  7. Microstructures and critical currents in high-{Tc} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Suenaga, Masaki

    1998-11-01

    Microstructural defects are the primary determining factors for the values of critical-current densities in a high {Tc} superconductor after the electronic anisotropy along the a-b plane and the c-direction. A review is made to assess firstly what would be the maximum achievable critical-current density in YBa{sub 2}Cu{sub 3}O{sub 7} if nearly ideal pinning sites were introduced and secondly what types of pinning defects are currently introduced or exist in YBa{sub 2}Cu{sub 3}O{sub 7} and how effective are these in pinning vortices.

  8. Current management of locally recurrent rectal cancer

    DEFF Research Database (Denmark)

    Nielsen, Mette Bak; Laurberg, Søren; Holm, Thorbjörn

    2011-01-01

    ABSTRACT Objective: A review of the literature was undertaken to provide an overview of the surgical management of locally recurrent rectal cancer (LRRC) after the introduction of total mesorectal excision (TME). Method: A systematic literature search was undertaken using PubMed, Embase, Web...

  9. Local ecosystem feedbacks and critical transitions in the climate

    Directory of Open Access Journals (Sweden)

    M. Rietkerk

    2009-10-01

    Full Text Available Global and regional climate models, such as those used in IPCC assessments, are the best tools available for climate predictions. Such models typically account for large-scale land-atmosphere feedbacks. However, these models omit local vegetation-environment feedbacks that are crucial for critical transitions in ecosystems. Here, we reveal the hypothesis that, if the balance of feedbacks is positive at all scales, local vegetation-environment feedbacks may trigger a cascade of amplifying effects, propagating from local to large scale, possibly leading to critical transitions in the large-scale climate. We call for linking local ecosystem feedbacks with large-scale land-atmosphere feedbacks in global and regional climate models in order to yield climate predictions that we are more confident about.

  10. Scaling rules for critical current density in anisotropic biaxial superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yingxu, E-mail: yingxuli@swjtu.edu.cn [Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province, School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Kang, Guozheng [Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province, School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Gao, Yuanwen, E-mail: ywgao@lzu.edu.cn [Key Laboratory of Mechanics on Environment and Disaster in Western China, The Ministry of Education of China, Lanzhou, Gansu 730000 (China); Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)

    2016-06-15

    Recent researches highlight the additional anisotropic crystallographic axis within the superconducting plane of high temperature superconductors (HTS), demonstrating the superconducting anisotropy of HTS is better understood in the biaxial frame than the previous uniaxial coordinates within the superconducting layer. To quantitatively evaluate the anisotropy of flux pinning and critical current density in HTS, we extend the scaling rule for single-vortex collective pinning in uniaxial superconductors to account for flux-bundle collective pinning in biaxial superconductors. The scaling results show that in a system of random uncorrected point defects, the field dependence of the critical current density is described by a unified function with the scaled magnetic field of the isotropic superconductor. The obtained angular dependence of the critical current density depicts the main features of experimental observations, considering possible corrections due to the strong-pinning interaction.

  11. Critical current characteristics and history dependence in superconducting SmFeAsOF bulk

    Energy Technology Data Exchange (ETDEWEB)

    Ni, B; Ge, J [Department of Life, Environment and Materials Science, Fukuoka Institute of Technology, Fukuoka 811-0295 (Japan); Kiuchi, M; Otabe, E S [Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka 820-8502 (Japan); Gao, Z; Wang, L; Qi, Y; Zhang, X; Ma, Y, E-mail: nee@fit.ac.j [Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, PO Box 2703, Beijing 100190 (China)

    2010-06-01

    The superconducting SmFeAsO{sub 1-x}F{sub x} (x=0.2) polycrystalline bulks were prepared by the powder-in-tube (PIT) method. The magnetic field and temperature dependences of critical current densities in the samples were investigated by resistive and ac inductive (Campbell's) methods. It was found that a fairly large shielding current density over 10{sup 9} A/m{sup 2}, which is considered to correspond to the local critical current density, flows locally with the perimeter size similar to the average grain size of the bulk samples, while an extremely low transport current density of about 10{sup 5} A/m{sup 2} corresponding to the global critical current density flows through the whole sample. Furthermore, a unique history dependence of global critical current density was observed, i.e., it shows a smaller value in the increasing-field process than that in the decreasing-field process. The history dependence of global critical current characteristic in our case can be ascribed to the existence of the weak-link property between the grains in SmFeAsO{sub 1-x}F{sub x} bulk.

  12. Critical current characteristics and history dependence in superconducting SmFeAsOF bulk

    Science.gov (United States)

    Ni, B.; Ge, J.; Kiuchi, M.; Otabe, E. S.; Gao, Z.; Wang, L.; Qi, Y.; Zhang, X.; Ma, Y.

    2010-06-01

    The superconducting SmFeAsO1-xFx (x=0.2) polycrystalline bulks were prepared by the powder-in-tube (PIT) method. The magnetic field and temperature dependences of critical current densities in the samples were investigated by resistive and ac inductive (Campbell's) methods. It was found that a fairly large shielding current density over 109 A/m2, which is considered to correspond to the local critical current density, flows locally with the perimeter size similar to the average grain size of the bulk samples, while an extremely low transport current density of about 105 A/m2 corresponding to the global critical current density flows through the whole sample. Furthermore, a unique history dependence of global critical current density was observed, i.e., it shows a smaller value in the increasing-field process than that in the decreasing-field process. The history dependence of global critical current characteristic in our case can be ascribed to the existence of the weak-link property between the grains in SmFeAsO1-xFx bulk.

  13. Engineering Critical Current Density Improvement in Ag- Bi-2223 Tapes

    DEFF Research Database (Denmark)

    Wang, W. G.; Seifi, Behrouz; Eriksen, Morten;

    2000-01-01

    Ag alloy sheathed Bi-2223 multifilament tapes were produced by the powder-in-tube method. Engineering critical current density improvement has been achieved through both enhancement of critical current density by control of the thermal behavior of oxide powder and by an increase of the filling...... the superconductor composite sustaining large proportional oxide ceramics in the composite during drawing and rolling process. By optimization of the thermal and mechanical process, a Je of 12 kA/cm2 has been achieved in a 0.183.1 mm2 size tape which carried 67 A...

  14. Strand critical current degradation in $Nb_{3}$ Sn Rutherford cables

    CERN Document Server

    Barzi, E; Higley, H C; Scanlan, R M; Yamada, R; Zlobin, A V

    2001-01-01

    Fermilab is developing 11 Tesla superconducting accelerator magnets based on Nb/sub 3/Sn superconductor. Multifilamentary Nb/sub 3/Sn strands produced using the modified jelly roll, internal tin, and powder-in-tube technologies were used for the development and test of the prototype cable. To optimize the cable geometry with respect to the critical current, short samples of Rutherford cable with packing factors in the 85 to 95% range were fabricated and studied. In this paper, the results of measurements of critical current, n-value and RRR made on the round virgin strands and on the strands extracted from the cable samples are presented. (5 refs).

  15. Interlaboratory Comparisons of NbTi Critical Current Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Godeke, A.; Turrioni, D.; Boutboul, T.; Cheggour, N.; Goodrich, L.F.; Ghosh, A.; Den Ouden, A.; Meinesz, M.

    2009-08-16

    We report on a multi-institute comparison of critical current data measured on a modern NbTi wire for the Large Hadron Collider (LHC), which has shown a standard deviation below 1% in critical current density spread in more than 1500 measurements. Interlaboratory comparisons on Nb{sub 3}Sn wires have shown ambiguities that could be attributable to strain related differences in critical current density, originating from differences in sample handling, reaction, and mounting techniques, or also to differences in the magnetic field and current calibrations between the institutes. A round robin test of a well characterized NbTi wire provides a baseline variance in critical current results that is presumed to be attributable only to differences in the characterization systems. Systematic differences on the order of 3.5% are found in the comparison. The most likely cause for the observed differences is a small diameter holder that brings the wire into a strain regime in which strain effects can no longer be ignored. A NbTi round robin test, when performed properly, will separate system differences from sample specific differences and provide laboratories with an opportunity to calibrate equipment against a standard measurement.

  16. Critical Current Measurements in Commercial Tapes, Coils, and Magnets.

    Science.gov (United States)

    Gubser, D. U.; Soulen, R. J., Jr.; Fuller-Mora, W. W.; Francavilla, T. L.

    1996-03-01

    We have measured a number of tapes, coils, and magnets produced by commercial vendors and determined their properties as functions of magnetic field and temperature. The tapes were measured at the National High Magnetic Field Laboratory in magnetic fields to 20 tesla and at temperatures of 4.2 K, 27 K, 65 K, and 77 K. For the tapes we report critical currents and current-voltage characteristics. Six inch diameter coils were measured at NRL in zero magnetic field. Critical currents, current-voltage characteristics, and reliability studies are reported for the coils. Larger 10 inch diameter coils, which are to be used in a 200 hp superconducting motor, were also measured and results will be presented. The talk will also review the status of the most recent tests of the superconducting motor.

  17. Effect of heating on critical current of YBCO nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Golubev, D., E-mail: dmitry.golubev@aalto.fi [Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, 00076 Aalto (Finland); Institute of Nanotechnology, Karlsruhe Institute of Technology, D-76021 Karlsruhe (Germany); Lombardi, F.; Bauch, T. [Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-412 96 Göteborg (Sweden)

    2014-11-15

    Highlights: • We discuss transport of heat in YBCO nanowires and its implications to their superconducting properties. • We demonstrate that in long wires the measured value of the critical current may be much lower than its theoretical value. • Our results may be interesting in view of potential applications of YBCO nanowires in detectors of radiation. - Abstract: We discuss transport of heat in YBCO nanowires and its implications to their superconducting properties. We find under which conditions the central part of a nanowire may turn normal. We demonstrate that in long wires it may happen at currents much lower than the theoretical value of superconducting critical current. We derive a simple formula for the corresponding threshold current in terms of the heat transport parameters of YBCO. Our results may be interesting in view of potential applications of YBCO nanowires in detectors of radiation.

  18. Critical current and electronic properties of YBCO-Ag compounds

    Energy Technology Data Exchange (ETDEWEB)

    Dwir, B.; Affronte, M.; Pavuna, D. (Physics Dept., Swiss Federal Inst. of Tech., Lausanne (Switzerland))

    1989-12-01

    We have found that in YBCO-Ag ceramic compounds Ag fills the intergranular space (''holes'') without affecting Tc. Normal-state resistivity is decreased by {approx equal} x 100 when adding up to 50 wt% Ag. Percolation analysis shows that the critical indices t,s are in agreement with 3D theoretical values, but p{sub c} is higher than expected. The critical current density J{sub c} is enhanced by up to 50% in the samples containing {approx equal} 10 wt% Ag, this enhancement corresponds to a maximum YBCO compactness in the samples. (orig.).

  19. Hawking Radiation and Nonequilibrium Quantum Critical Current Noise

    Science.gov (United States)

    Sonner, Julian; Green, A. G.

    2012-08-01

    The dynamical scaling of quantum critical systems in thermal equilibrium may be inherited in the driven steady state, leading to universal out-of-equilibrium behavior. This attractive notion has been demonstrated in just a few cases. We demonstrate how holography—a mapping between the quantum critical system and a gravity dual—provides an illuminating perspective and new results. Nontrivial out-of-equilibrium universality is particularly apparent in current noise, which is dual to Hawking radiation in the gravitational system. We calculate this in a two-dimensional system driven by a strong in-plane electric field and deduce a universal scaling function interpolating between previously established equilibrium and far-from-equilibrium current noise. Since this applies at all fields, out-of-equilibrium experiments no longer require very high fields for comparison with theory.

  20. Transport critical current of MgB2 wires: pulsed current of varying rate compared to direct current method

    Science.gov (United States)

    See, K. W.; Xu, X.; Horvat, J.; Cook, C. D.; Dou, S. X.

    2011-10-01

    The measurement of transport critical current (Ic) for MgB2 wires and tapes has been investigated with two different techniques, the conventional four-probe arrangement with direct current (DC) power source, and a tailored triangle pulse at different rates of current change. The DC method has been widely used and practiced by various groups, but suffers from inevitable heating effects when high currents are used at low magnetic fields. The pulsed current method has no heating effects, but the critical current can depend on the rate of the current change (dI/dt) in the pulse. Our pulsed current measurements with varying dI/dt show that the same values of Ic are obtained as with the DC method, but without the artifacts of heating. Our method is particularly useful at low field regions which are often inaccessible by DC methods. We also performed a finite element method (FEM) analysis to obtain the time dependent heat distribution in MgB2 due to the electric potential produced at the current contacts to the superconducting sample and its gradient around the contacts. This gradient is defined as the current transfer length (CTL) of the samples and leads to Joule heating of the wire near the contacts. The FEM results provide further evidence of the limitation of the DC method in obtaining high transport critical current.

  1. Non-local currents and the structure of eigenstates in planar discrete systems with local symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Röntgen, M., E-mail: mroentge@physnet.uni-hamburg.de [Zentrum für optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Morfonios, C.V., E-mail: christian.morfonios@physnet.uni-hamburg.de [Zentrum für optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Diakonos, F.K., E-mail: fdiakono@phys.uoa.gr [Department of Physics, University of Athens, GR-15771 Athens (Greece); Schmelcher, P., E-mail: pschmelc@physnet.uni-hamburg.de [Zentrum für optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)

    2017-05-15

    Local symmetries are spatial symmetries present in a subdomain of a complex system. By using and extending a framework of so-called non-local currents that has been established recently, we show that one can gain knowledge about the structure of eigenstates in locally symmetric setups through a Kirchhoff-type law for the non-local currents. The framework is applicable to all discrete planar Schrödinger setups, including those with non-uniform connectivity. Conditions for spatially constant non-local currents are derived and we explore two types of locally symmetric subsystems in detail, closed-loops and one-dimensional open ended chains. We find these systems to support locally similar or even locally symmetric eigenstates. - Highlights: • We extend the framework of non-local currents to discrete planar systems. • Structural information about the eigenstates is gained. • Conditions for the constancy of non-local currents are derived. • We use the framework to design two types of example systems featuring locally symmetric eigenstates.

  2. MOS: A critical tool for current and future radio surveys

    CERN Document Server

    Smith, Daniel J B

    2015-01-01

    Since radio continuum observations are not affected by dust obscuration, they are of immense potential diagnostic power as cosmological probes and for studying galaxy formation and evolution out to high redshifts. However, the power-law nature of radio frequency spectra ensures that ancillary spectroscopic information remains critical for studying the properties of the faint radio sources being detected in rapidly-increasing numbers on the pathway to the Square Kilometre Array. In this contribution, I present some of the key scientific motivations for exploiting the immense synergies between radio continuum observations and multi-object spectroscopic surveys. I review some of the ongoing efforts to obtain the spectra necessary to harness the huge numbers of star-forming galaxies and AGN that current and future radio surveys will detect. I also touch on the WEAVE-LOFAR survey, which will use the WEAVE spectrograph currently being built for the William Herschel Telescope to target hundreds of thousands of low f...

  3. Local Government and Local Development: Bridging the Gap through Critical Discourse: Evidence from the Commonwealth Caribbean

    Directory of Open Access Journals (Sweden)

    Eris D Schoburgh

    2012-08-01

    Full Text Available Local development, whether construed broadly as community development or more narrowly as local as economic development (LED is not always associated with local government but rather is the purview of a central government department or agency in Anglophone Caribbean policy systems. However with the emergence of ‘local place - and people-oriented approaches’ to development that offer new propositions about how to respond to risks and opportunities brought by globalization, local government is seen increasingly as an appropriate institutional context in which to pursue short-range objectives, such as creation of market opportunities and redressing the disparities within national economies; as well as the long-range goal of social transformation. A developmental role for local government raises two questions that form the central concerns of this paper: What are the institutional and organisational imperatives of a developmental role for local government? To what extent have these imperatives been addressed in reform? A critical analysis of local government reform policies in Trinidad and Tobago and Jamaica revealed substantive convergence around local development as an outcome of reform but also important divergence in the approach to achieving this goal which suggests the absence of a cohesive model. The paper argues for a new agenda in reform that links local government more consistently with a local development strategy. It asserts that such a strategy must incorporate gender equality, the informal economy and institutional organisational capacity in the process of transformation and as a basis for creating a local context in which all types of resources can be maximized in the process of wealth creation in a locality.

  4. Critical Properties of the Many-Body Localization Transition

    Science.gov (United States)

    Khemani, Vedika; Lim, S. P.; Sheng, D. N.; Huse, David A.

    2017-04-01

    The transition from a many-body localized phase to a thermalizing one is a dynamical quantum phase transition that lies outside the framework of equilibrium statistical mechanics. We provide a detailed study of the critical properties of this transition at finite sizes in one dimension. We find that the entanglement entropy of small subsystems looks strongly subthermal in the quantum critical regime, which indicates that it varies discontinuously across the transition as the system size is taken to infinity, even though many other aspects of the transition look continuous. We also study the variance of the half-chain entanglement entropy, which shows a peak near the transition, and find substantial variation in the entropy across eigenstates of the same sample. Furthermore, the sample-to-sample variations in this quantity are strongly growing and are larger than the intrasample variations. We posit that these results are consistent with a picture in which the transition to the thermal phase is driven by an eigenstate-dependent sparse resonant "backbone" of long-range entanglement, which just barely gains enough strength to thermalize the system on the thermal side of the transition as the system size is taken to infinity. This discontinuity in a global quantity—the presence of a fully functional bath—in turn implies a discontinuity even for local properties. We discuss how this picture compares with existing renormalization group treatments of the transition.

  5. Fabrication and Enhancement of Critical Currents of Silver Sheathed

    Science.gov (United States)

    Hu, Qingyu

    X-ray diffraction was used to characterise the phase composition and to investigate the formation mechanism of the (Bi,Pb)_2Sr_2Ca_2Cu _3O_{10} phase from the precursor with (Bi,Pb)_2Sr_2CaCu _2O_8 as the main phase. The reaction is found to be a two-dimensional nucleation (random)-growth type, (-(ln(1-F)) ^{1/2} = kt, where F is the conversional fraction of (Bi,Pb) _2Sr_2CaCu_2O_8 phase and t is the sintering time. The two dimensional behaviour of the critical current in (Bi,Pb)_2Sr2Ca_2Cu _3O_{10}/Ag tapes was observed and analysed by introducing an effective grain misalignment angle, varphi_{eff}. This angle was found to be identical to the average crystallographic grain misalignment angle in the superconducting core. Furthermore, after fast neutron irradiation, which is isotropical, the J_{c}'s of the tapes were modified by the introduction of artificial defects, but the varphi_{eff}'s remained the same. The transport critical current of (Bi,Pb) _2Sr_2Ca_2Cu_3O_ {10}/Ag tapes was measured in magnetic fields up to 15 T and at temperatures from of 4.2 to 84 K. At high temperatures, the J_ {c} is strongly anisotropic and the anisotropy increases rapidly with magnetic field, whereas at low temperatures the critical current is less anisotropic and the anisotropy is almost field independent above 1 T. The transport J_{c }'s in (Bi,Pb)_2Sr_2Ca _2Cu_3O_{10}/Ag tapes at 77 K and higher magnetic fields after neutron irradiation are significantly enhanced. This enhancement is attributed to an improvement in the flux pinning capability of this material by the neutron-induced defects. The angular dependence of J_{c} is still consistent with two-dimensionality, i.e. flux pinning of pancake and/or Josephson vortices is directly confirmed by this transport measurement. Short multifilamentary (Bi,Pb)_2Sr_2Ca_2Cu_2O_{10 }/Ag tapes were fabricated. The sintering parameters were optimised to be 832^circ C and 180 h. The multifilamentary tape consists mainly of pure (Bi,Pb)_2Sr_2Ca

  6. Local Hubble Expansion: Current State of the Problem

    CERN Document Server

    Dumin, Yurii V

    2016-01-01

    We present a brief qualitative overview of the current state of the problem of Hubble expansion at the sufficiently small scales (e.g., in planetary systems or local intergalactic volume). The crucial drawbacks of the available theoretical treatments are emphasized, and the possible ways to avoid them are outlined. Attention is drawn to a number of observable astronomical phenomena that could be naturally explained by the local Hubble expansion.

  7. Critical thresholds in flocking hydrodynamics with non-local alignment.

    Science.gov (United States)

    Tadmor, Eitan; Tan, Changhui

    2014-11-13

    We study the large-time behaviour of Eulerian systems augmented with non-local alignment. Such systems arise as hydrodynamic descriptions of agent-based models for self-organized dynamics, e.g. Cucker & Smale (2007 IEEE Trans. Autom. Control 52, 852-862. (doi:10.1109/TAC.2007.895842)) and Motsch & Tadmor (2011 J. Stat. Phys. 144, 923-947. (doi:10.1007/s10955-011-0285-9)) models. We prove that, in analogy with the agent-based models, the presence of non-local alignment enforces strong solutions to self-organize into a macroscopic flock. This then raises the question of existence of such strong solutions. We address this question in one- and two-dimensional set-ups, proving global regularity for subcritical initial data. Indeed, we show that there exist critical thresholds in the phase space of the initial configuration which dictate the global regularity versus a finite-time blow-up. In particular, we explore the regularity of non-local alignment in the presence of vacuum.

  8. Mapping the current–current correlation function near a quantum critical point

    Energy Technology Data Exchange (ETDEWEB)

    Prodan, Emil, E-mail: prodan@yu.edu [Department of Physics, Yeshiva University, New York, NY 10016 (United States); Bellissard, Jean [School of Mathematics and School of Physics, Georgia Institute of Technology, Atlanta, GA (United States)

    2016-05-15

    The current–current correlation function is a useful concept in the theory of electron transport in homogeneous solids. The finite-temperature conductivity tensor as well as Anderson’s localization length can be computed entirely from this correlation function. Based on the critical behavior of these two physical quantities near the plateau–insulator or plateau–plateau transitions in the integer quantum Hall effect, we derive an asymptotic formula for the current–current correlation function, which enables us to make several theoretical predictions about its generic behavior. For the disordered Hofstadter model, we employ numerical simulations to map the current–current correlation function, obtain its asymptotic form near a critical point and confirm the theoretical predictions.

  9. Development of high temperature superconductors having high critical current density

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Gye Wong; Kim, C. J.; Lee, H.G.; Kwon, S. C.; Lee, H. J.; Kim, K. B.; Park, J. Y.; Jung, C. H

    2000-08-01

    Fabrication of high T{sub c} superconductors and its applications for electric power device were carried out for developing superconductor application technologies. High quality YBCO superconductors was fabricated by melt texture growth, top-seeded melt growth process and multi-seeded melt growth process and the properties was compared. The critical current density of the melt processed YBCO superconductors was about few 10,000 A/cm{sup 2} and the levitation force was 50 N. The processing time needed for the growth of the 123 single grain was greatly reduced by applying multi-seeding without no significant degradation of the levitation force. The multi-seeded melt growth process was confirmed as a time-saving and cost-effective method for the fabrication of bulk superconductors with controlled crystallographic orientation.

  10. Critical current densities in Bi-2223 sinter forgings.

    Energy Technology Data Exchange (ETDEWEB)

    Balachandran, U.; Fisher, B. L.; Goretta, K. C.; Harris, N. C.; Murayama, N.

    1999-07-23

    (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Bi-2223) bars, prepared by sinter forging, exhibited good phase purity and strong textures with the c axes of the Bi-2223 grains parallel to the forging direction. The initial zero-field critical current density (J{sub c}) of the bars was 10{sup 3} A/cm{sup 2}, but because the forged bars were uncoated, this value decreased with repeated thermal cycling. J{sub c} as a function of applied magnetic field magnitude and direction roughly followed the dependencies exhibited by Ag-sheathed Bi-2223 tapes, but the forged bars were more strongly dependent on field strength and less strongly dependent on field angle.

  11. Caffeine and cardiovascular diseases: critical review of current research.

    Science.gov (United States)

    Zulli, Anthony; Smith, Renee M; Kubatka, Peter; Novak, Jan; Uehara, Yoshio; Loftus, Hayley; Qaradakhi, Tawar; Pohanka, Miroslav; Kobyliak, Nazarii; Zagatina, Angela; Klimas, Jan; Hayes, Alan; La Rocca, Giampiero; Soucek, Miroslav; Kruzliak, Peter

    2016-06-01

    Caffeine is a most widely consumed physiological stimulant worldwide, which is consumed via natural sources, such as coffee and tea, and now marketed sources such as energy drinks and other dietary supplements. This wide use has led to concerns regarding the safety of caffeine and its proposed beneficial role in alertness, performance and energy expenditure and side effects in the cardiovascular system. The question remains "Which dose is safe?", as the population does not appear to adhere to the strict guidelines listed on caffeine consumption. Studies in humans and animal models yield controversial results, which can be explained by population, type and dose of caffeine and low statistical power. This review will focus on comprehensive and critical review of the current literature and provide an avenue for further study.

  12. Targeted temperature management: Current evidence and practices in critical care

    Directory of Open Access Journals (Sweden)

    Saurabh Saigal

    2015-01-01

    Full Text Available Targeted temperature management (TTM in today′s modern era, especially in intensive care units represents a promising multifaceted therapy for a variety of conditions. Though hypothermia is being used since Hippocratic era, the renewed interest of late has been since early 21 st century. There have been multiple advancements in this field and varieties of cooling devices are available at present. TTM requires careful titration of its depth, duration and rewarming as it is associated with side-effects. The purpose of this review is to find out the best evidence-based clinical practice criteria of therapeutic hypothermia in critical care settings. TTM is an unique therapeutic modality for salvaging neurological tissue viability in critically ill patients viz. Post-cardiac arrest, traumatic brain injury (TBI, meningitis, acute liver failure and stroke. TTM is standard of care in post-cardiac arrest situations; there has been a lot of controversy of late regarding temperature ranges to be used for the same. In patients with TBI, it reduces intracranial pressure, but has not shown any favorable neurologic outcome. Hypothermia is generally accepted treatment for hypoxic ischemic encephalopathy in newborns. The current available technology to induce and maintain hypothermia allows for precise temperature control. Future studies should focus on optimizing hypothermic treatment to full benefit of our patients and its application in other clinical scenarios.

  13. Mill’s Liberal Feminism: Its Legacy and Current Criticism

    Directory of Open Access Journals (Sweden)

    MARIANA SZAPUOVÁ

    2006-12-01

    Full Text Available This paper highlights John Stuart Mill’s views on the problem of gender equality as expressed in The Subjection of Women, which is commonly regarded as one of the core texts of Enlightenment liberal feminism of the 19th century. In this paper, the author outlines the historical context of both Mill’s views and his personal biography, which influenced his argumentation for the emancipation of women, and considers Mill’s utilitarianism and liberalism, as the main philosophical background for his criticism of social conditions that subordinated women. She reflects on some of the philosopher’s ideas and arguments for equality and friendship between women and men which may still be considered noteworthy and relevant. Attention is also given to the main lines of contemporary reception of Mill’s liberal feminism from the perspective of current feminist philosophy, within which certain critical views predominate. Despite some problematic points in Mill’s considerations, his essay on women’s subjection may be regarded as one of the philosophically most interesting conceptions of liberal feminist thinking.

  14. Current options in local anesthesia for groin hernia repairs.

    Science.gov (United States)

    Kulacoglu, Hakan; Alptekin, Alp

    2011-01-01

    Inguinal hernia repair is one of the most common procedures in general surgery. All anesthetic methods can be used in inguinal hernia repairs. Local anesthesia for groin hernia repair had been introduced at the very beginning of the last century, and gained popularity following the success reports from the Shouldice Hospital, and the Lichtenstein Hernia Institute. Today, local anesthesia is routinely used in specialized hernia clinics, whereas its use is still not a common practice in general hospitals, in spite of its proven advantages and recommendations by current hernia repair guidelines. In this review, the technical options for local anaesthesia in groin hernia repairs, commonly used local anaesthetics and their doses, potential complications related to the technique are evaluated. A comparison of local, general and regional anesthesia methods is also presented. Local anaesthesia technique has a short learning curve requiring simple training. It is easy to learn and apply, and its use is in open anterior repairs a nice way for health care economics. Local anesthesia has been shown to have certain advantages over general and regional anesthesia in inguinal hernia repairs. It is more economic and requires a shorter time in the operating room and shorter stay in the institution. It causes less postoperative pain, requires less analgesic consumption; avoids nausea, vomiting, and urinary retention. Patients can mobilize and take oral liquids and solid foods much earlier. Most importantly, local anesthesia is the most suitable type of anesthesia in elder, fragile patients and patients with ASA II-IV scores.

  15. Local structure of the magnetotail current sheet: 2001 Cluster observations

    Directory of Open Access Journals (Sweden)

    A. Runov

    2006-03-01

    Full Text Available Thirty rapid crossings of the magnetotail current sheet by the Cluster spacecraft during July-October 2001 at a geocentric distance of 19 RE are examined in detail to address the structure of the current sheet. We use four-point magnetic field measurements to estimate electric current density; the current sheet spatial scale is estimated by integration of the translation velocity calculated from the magnetic field temporal and spatial derivatives. The local normal-related coordinate system for each case is defined by the combining Minimum Variance Analysis (MVA and the curlometer technique. Numerical parameters characterizing the plasma sheet conditions for these crossings are provided to facilitate future comparisons with theoretical models. Three types of current sheet distributions are distinguished: center-peaked (type I, bifurcated (type II and asymmetric (type III sheets. Comparison to plasma parameter distributions show that practically all cases display non-Harris-type behavior, i.e. interior current peaks are embedded into a thicker plasma sheet. The asymmetric sheets with an off-equatorial current density peak most likely have a transient nature. The ion contribution to the electric current rarely agrees with the current computed using the curlometer technique, indicating that either the electron contribution to the current is strong and variable, or the current density is spatially or temporally structured.

  16. Invariant currents in lossy acoustic waveguides with complete local symmetry

    CERN Document Server

    Kalozoumis, P A; Diakonos, F K; Theocharis, G; Schmelcher, P

    2015-01-01

    We implement the concept of complete local symmetry in lossy acoustic waveguides. Despite the presence of losses, the existence of a spatially invariant current is shown theoretically and observed experimentally. We demonstrate how this invariant current leads to the generalization of the Bloch and parity theorems for lossy systems defining a mapping of the pressure field between symmetry related spatial domains. Using experimental data we verify this mapping with remarkable accuracy. For the performed experiment we employ a construction technique based on local symmetries which allows the design of setups with prescribed perfect transmission resonances in the lossless case. Our results reveal the fundamental role of symmetries in restricted spatial domains and clearly indicate that completely locally symmetric devices constitute a promising class of setups, regarding the manipulation of wave propagation.

  17. Mechanism for the uniaxial strain dependence of the critical current in practical REBCO tapes

    Science.gov (United States)

    Osamura, Kozo; Machiya, Shutaro; Hampshire, Damian P.

    2016-06-01

    In order to elucidate the effect of uniaxial strain on the critical current of practical REBCO tapes (REBa2Cu3O7-d , RE = Y and Gd) fabricated by Superpower and SuNAM, two types of critical current measurements were carried out. In the first, the tape sample was attached directly to a universal testing machine and pulled under a tensile load. In the second, the tape was soldered to a Cu-Be springboard and then attached to the testing machine and then pushed or pulled in order to apply both tensile and compressive strains to the tape sample. An inverse parabolic behaviour was observed for the uniaxial strain dependence of the critical current of both tapes. Using synchrotron radiation, the local strain exerted on the REBCO layer was measured at room temperature under the conditions used for the two techniques for making I c measurements. On the basis of these room temperature data, the local strain exerted on the REBCO layer at 77 K was numerically evaluated. A one-dimensional chain model for current flow in the REBCO material with fractional lengths of A-domains and B-domains oriented along the uniaxial strain direction is proposed. The model can explain the parabolic strain behaviour of the critical current and shows that the strain at which the peak in I c occurs, is not only determined by pre-compression or pre-tension on the superconductor at the operating temperature, but also by the ratio of the fractional amounts of the two domains.

  18. Adjuvants to local anesthetics: Current understanding and future trends

    Science.gov (United States)

    Swain, Amlan; Nag, Deb Sanjay; Sahu, Seelora; Samaddar, Devi Prasad

    2017-01-01

    Although beneficial in acute and chronic pain management, the use of local anaesthetics is limited by its duration of action and the dose dependent adverse effects on the cardiac and central nervous system. Adjuvants or additives are often used with local anaesthetics for its synergistic effect by prolonging the duration of sensory-motor block and limiting the cumulative dose requirement of local anaesthetics. The armamentarium of local anesthetic adjuvants have evolved over time from classical opioids to a wide array of drugs spanning several groups and varying mechanisms of action. A large array of opioids ranging from morphine, fentanyl and sufentanyl to hydromorphone, buprenorphine and tramadol has been used with varying success. However, their use has been limited by their adverse effect like respiratory depression, nausea, vomiting and pruritus, especially with its neuraxial use. Epinephrine potentiates the local anesthetics by its antinociceptive properties mediated by alpha-2 adrenoreceptor activation along with its vasoconstrictive properties limiting the systemic absorption of local anesthetics. Alpha 2 adrenoreceptor antagonists like clonidine and dexmedetomidine are one of the most widely used class of local anesthetic adjuvants. Other drugs like steroids (dexamethasone), anti-inflammatory agents (parecoxib and lornoxicam), midazolam, ketamine, magnesium sulfate and neostigmine have also been used with mixed success. The concern regarding the safety profile of these adjuvants is due to its potential neurotoxicity and neurological complications which necessitate further research in this direction. Current research is directed towards a search for agents and techniques which would prolong local anaesthetic action without its deleterious effects. This includes novel approaches like use of charged molecules to produce local anaesthetic action (tonicaine and n butyl tetracaine), new age delivery mechanisms for prolonged bioavailability (liposomal

  19. Scanning Hall-probe microscopy system for two-dimensional imaging of critical current density in RE-123 coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Higashikawa, K., E-mail: kohei@super.ees.kyushu-u.ac.jp [Department of Electrical Engineering, Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Inoue, M.; Kawaguchi, T.; Shiohara, K.; Imamura, K.; Kiss, T. [Department of Electrical Engineering, Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Iijima, Y.; Kakimoto, K.; Saitoh, T. [Material Technology Laboratory, Fujikura, 1-5-1, Kiba, Koto-ku, Tokyo 135-8512 (Japan); Izumi, T. [Superconductivity Research Laboratory, International Superconductivity Technology Center, 1-10-13 Shinonome, Koto-ku, Tokyo 135-0062 (Japan)

    2011-11-15

    Nondestructive characterization method of in-plane distribution of critical current density for coated conductors. Current distribution in a coated conductor compared with that from theoretical analysis. Relationship between local critical current density and local magnetic field. We have developed a characterization method for two-dimensional imaging of critical current density in coated conductors (CCs) based on scanning Hall-probe microscopy (SHPM). The distributions of the magnetic field around a sample were measured for several different conditions of external magnetic fields, and then were converted to those of the sheet current density which flowed to shield the external magnetic field or to trap the penetrated magnetic field. As a result, it was found that the amplitude of the sheet current density corresponded to that of critical current density almost in all the area of the sample except for the region where current direction changed. This indicates that we could obtain an in-plane distribution of the critical current density with a spatial resolution of around 100 {mu}m in non-destructive manner by this method. We believe that this measurement will be a multifunctional and comprehensive characterization method for coated conductors.

  20. Characterization of the critical current and physical properties of superconducting epitaxial NbTiN sub-micron structures

    Energy Technology Data Exchange (ETDEWEB)

    Klimov, A., E-mail: aklimov@ite.waw.pl [Institute of Electron Technology, Al. Lotników 32/46, 02-668 Warsaw (Poland); Słysz, W.; Guziewicz, M. [Institute of Electron Technology, Al. Lotników 32/46, 02-668 Warsaw (Poland); Kolkovsky, V.; Zaytseva, I.; Malinowski, A. [Institute of Physics Polish Academy of Science, Al. Lotników 32/46, 02-668 Warsaw (Poland)

    2017-05-15

    Highlights: • This manuscript presents investigation of the critical current dependence of Nb(Ti)N nanostructured superconducting single photon detectors (SNSPD) in function of temperature and applied magnetic field. • Presented results are complimentary and compared with the same data received for submicron-wide single bridge Nb(Ti)N structures. • Our data demonstrate significant influence of local constrictions on physical properties of our SNSPD detectors. - Abstract: Measurements of critical current in NbTiN as a function of applied magnetic field and temperature are reported for two samples: 700-nm-wide bridge and 100-nm-wide meander. In 700-nm-wide NbTiN bridge we pinpointed the limiting factors for the critical current density to be current-driven vortex de-pinning at low temperatures and thermally activated flux flow closer to the transition temperature. In 100-nm-wide NbTiN meander we found phase slips activation, accompanied by hotspots formation at all measured temperatures. These two types of structures demonstrate different dependence of the critical current on the applied magnetic field. Although our NbTiN meander structures has high de-pairing critical current densities ∼10{sup 7} A/cm{sup 2} at low temperatures, the real critical currents are smaller due to the presence of the local constrictions.

  1. Vibration effect on magnetization and critical current density of superconductors

    Science.gov (United States)

    Golovchanskiy, Igor A.; Pan, Alexey V.; George, Jonathan; Wells, Frederick S.; Fedoseev, Sergey A.; Rozenfeld, Anatoly

    2016-07-01

    In this work the effect of vibrations on critical current density (J c ) of superconductors has been studied. The vibrations are shown to affect J c of all types of superconductors during their measurements, employing a vibrating sample magnetometer (VSM). Increasing vibration frequency (f) and/or amplitude (A) leads to progressive reduction of J c as a function of magnetic field (B a ). The effect of vibrations is substantially stronger in thin films. It leads to development of unexpected kinks on {J}c({B}a) curves. Analysis of magnetization loops and relaxation of magnetization in YBCO films revealed that the vibration effect can be treated as the effective reduction of pinning potential. The asymmetry of the vibration effect in ascending and descending B a is observed, indicating differences in free energy of the corresponding vortex structures. Thermal effects induced by vibrations with large f and A are shown to have rather insignificant influence, while the vibrational vortex dynamics exhibit a strong impact. The irreversibility field ({B}{{irr}}) is shown to be instrumentally defined, and its value depends on VSM settings. In addition, the practical importance of {B}{{irr}} for J c modeling is demonstrated.

  2. Semi-local quantum criticality in string/M-theory

    CERN Document Server

    Donos, Aristomenis; Pantelidou, Christiana

    2012-01-01

    Semi-local quantum critical behaviour in $D-1$ spacetime dimensions can be holographically described by metrics that are conformal to $AdS_2\\times\\mathbb{R}^{D-2}$, with the conformal factor characterised by a parameter $\\eta$. We analyse such "$\\eta$-geometries" in a top-down setting by focussing on the $U(1)^4$ truncation of D=4 N=8 gauged supergravity. The model has extremal black hole solutions carrying three non-zero electric or magnetic charges which approach $AdS_4$ in the UV and an $\\eta=1$ geometry in the IR. Adding a fourth charge provides a mechanism to resolve the singularity of the $\\eta$-geometry, replacing it with an $AdS_2\\times\\mathbb{R}^2$ factor in the IR, while maintaining a large region where the $\\eta$-geometry scaling is approximately valid. Some of the magnetically charged black hole solutions preserve supersymmetry while others just preserve it in the IR. Finally, we show that $\\eta$-geometries, with various values of $\\eta$, can be obtained from the dimensional reduction of geometrie...

  3. Invariant currents and scattering off locally symmetric potential landscapes

    Science.gov (United States)

    Kalozoumis, P. A.; Morfonios, C. V.; Diakonos, F. K.; Schmelcher, P.

    2015-11-01

    We study the effect of discrete symmetry breaking in inhomogeneous scattering media within the framework of generic wave propagation. Our focus is on one-dimensional scattering potentials exhibiting local symmetries. We find a class of spatially invariant nonlocal currents, emerging when the corresponding generalized potential exhibits symmetries in arbitrary spatial domains. These invariants characterize the wave propagation and provide a spatial mapping of the wave function between any symmetry related domains. This generalizes the Bloch and parity theorems for broken reflection and translational symmetries, respectively. Their nonvanishing values indicate the symmetry breaking, whereas a zero value denotes the restoration of the global symmetry where the well-known forms of the two theorems are recovered. These invariants allow for a systematic treatment of systems with any local symmetry combination, providing a tool for the investigation of the scattering properties of aperiodic but locally symmetric systems. To this aim we express the transfer matrix of a locally symmetric potential unit via the corresponding invariants and derive quantities characterizing the complete scattering device which serve as key elements for the investigation of transmission spectra and particularly of perfect transmission resonances.

  4. Critical Values for Yen’s Q3: Identification of Local Dependence in the Rasch model using Residual Correlations

    DEFF Research Database (Denmark)

    Christensen, Karl Bang; Makransky, Guido; Horton, Mike

    2016-01-01

    The assumption of local independence is central to all IRT models. Violations can lead to inflated estimates of reliability and problems with construct validity. For the most widely used fit statistic Q3 there are currently no well-documented suggestions of the critical values which should be used...... guidelines that researchers and practitioners can follow when making decisions about local dependence during scale development and validation. We propose that a parametric bootstrapping procedure should be implemented in each separate situation in order to obtain the critical value of local dependence...... applicable to the data set, and provide example critical values for a number of data structure situations. The results show that for the Q3 fit statistic no single critical value is appropriate for all situations, as the percentiles in the empirical null distribution are influenced by the number of items...

  5. Local current mapping and patterning of reduced graphene oxide.

    Science.gov (United States)

    Mativetsky, Jeffrey M; Treossi, Emanuele; Orgiu, Emanuele; Melucci, Manuela; Veronese, Giulio Paolo; Samorì, Paolo; Palermo, Vincenzo

    2010-10-13

    Conductive atomic force microscopy (C-AFM) has been used to correlate the detailed structural and electrical characteristics of graphene derived from graphene oxide. Uniform large currents were measured over areas exceeding tens of micrometers in few-layer films, supporting the use of graphene as a transparent electrode material. Moreover, defects such as electrical discontinuities were easily detected. Multilayer films were found to have a higher conductivity per layer than single layers. It is also shown that a local AFM-tip-induced electrochemical reduction process can be used to pattern conductive pathways on otherwise-insulating graphene oxide. Transistors with micrometer-scale tip-reduced graphene channels that featured ambipolar transport and an 8 order of magnitude increase in current density upon reduction were successfully fabricated.

  6. Metatheoretical critics on current trends in Quantum Mechanics

    Directory of Open Access Journals (Sweden)

    Carlos C. Aranda

    2014-06-01

    Full Text Available Is our purpose in this article to review several approaches to modern problems in quantum mechanics from a critical point of view using the approximation of the traditional mathematical thinking. Nevertheless we point out several natural questions that arise in abstract mathematical reasoning.

  7. Postgraduate Research Supervision: A Critical Review of Current Practice

    Science.gov (United States)

    McCallin, Antoinette; Nayar, Shoba

    2012-01-01

    Changes in the funding and delivery of research programmes at the university level have, in recent years, resulted in significant changes to research supervision. This paper critically reviews key influences effecting postgraduate supervision. Analysis draws on literature spanning 2000-2010 to determine the appropriateness of traditional models of…

  8. Temperature Distribution and Critical Current of Long HTS Cables Cooled with Subcooled Liquid Nitrogen

    Science.gov (United States)

    Vyatkin, V. S.; Ivanov, Y. V.; Watanabe, H.; Chikumoto, N.; Yamaguchi, S.

    2017-07-01

    Cooling of the long HTS power transmission lines performs by pumping of subcooled liquid nitrogen (LN2) along the cable. The temperature of LN2 along the cable increases due to the heat losses of the cryostat and heat generation in the HTS cable. The experiment using test cable line in Ishikari shows that flow rate of 35 L/min retains increasing of LN2 temperature by 1 K per 1 km of length. The technology when the back flow of LN2 cools the radiation shield surrounding the cable pipe is also applied in Ishikari-2 project. In this case the ambient heat flow into cable pipe is 50 times less than that without radiation shield. Back flow of LN2 removes almost all heat coming from the environment. When transport current is close to the critical value the Joule heat of HTS cable is significant. This heat additionally increases the temperature of LN2 flowing along the HTS cable. Near the outlet the temperature of HTS cable is maximal and the local critical current is minimal. The current matching critical current criterion of average electrical field of E 0 = 10-4 V/m provides the voltage drop and significant Joule heat at the hot end of the cable. It can lead the damage of the cable. The present work contains analysis of temperature distribution along the cable and the way to achieve the fail-safe operation of long HTS cable cooled by subcooled LN2. We also performed extrapolation of obtained results for several times longer cable lines by decreasing the LN2 flow rate.

  9. Critical Language Awareness Part I: A Critical Review of Three Current Approaches to Language Awareness.

    Science.gov (United States)

    Clark, Romy; And Others

    1990-01-01

    Argues for a critical language awareness (LA) and for LA to be closely linked to the development of learners' practical language capabilities. The paper offers a critical evaluation of three major programmatic statements about LA: Committee for Linguistics in Education (1985); National Congress on Languages in Education (1985); and Hawkins (1984).…

  10. Kolmogorov complexity, Lovasz local lemma and critical exponents

    CERN Document Server

    Rumyantsev, Andrey

    2010-01-01

    D. Krieger and J. Shallit have proved that every real number greater than 1 is a critical exponent of some sequence. We show how this result can be derived from some general statements about sequences whose subsequences have (almost) maximal Kolmogorov complexity. In this way one can also construct a sequence that has no "approximate" fractional powers with exponent that exceeds a given value.

  11. Neural correlates of metacognition: A critical perspective on current tasks.

    Science.gov (United States)

    Insabato, Andrea; Pannunzi, Mario; Deco, Gustavo

    2016-12-01

    Humans have a remarkable ability to reflect upon their behavior and mental processes, a capacity known as metacognition. Recent neurophysiological experiments have attempted to elucidate the neural correlates of metacognition in other species. Despite this increased attention, there is still no operational definition of metacognition and the ability of behavioral tasks to reflect metacognition is the subject of debate. The most widely used task for studying metacognition in animals, the uncertain-option task, has been criticized because it can be solved by simple associative mechanisms. Here we propose a broad perspective that generalizes those critiques to another task, post-decision wagering. Moreover, we extend this critical view to account for recent neurophysiological evidence. We argue these tasks are simple enough that any animal could solve them using very simple mechanisms such as sensory-motor associations. In this case, it is impossible to know whether all animals are metacognitive, or if the tasks are simply not appropriate. Therefore, we suggest using better defined concepts until a suitable task for metacognition is available. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Managing Current Complexity: Critical Energy Infrastructure Failures in North America

    Directory of Open Access Journals (Sweden)

    Colin MacDonald

    2012-04-01

    Full Text Available

    This paper applies the competing theories of High Reliability Organizations (HRO and Normal Accidents Theory (NAT, two competing views of risk management in highly-complex and tightly-coupled systems, in analyzing the 1998 Ice Storm and the 2003 Blackout to examine vulnerabilities in North America’s critical energy infrastructure (CEI. Inferences are then made by highlighting the similarities and differences in the two cases, which are then used to draw lessons for public managers regarding the protection of CEIs.

     

    As CEIs are highly-complex and tightly-coupled systems, failures stemming from complex and uncertain risks are inevitable. There is an increasingly low tolerance for failure in energy infrastructure because society’s critical infrastructures have become increasingly interdependent. Public managers must regulate CEIs in order to ensure an emphasis is placed on safety and security while also finding ways to reduce unnecessary complexities. It is through the adoption of such measures that public managers will aid in minimizing the cascading effects of inevitable failures.

     

  13. Vortex-lattice pinning and critical current density in anisotropic high-temperature superconductors

    Science.gov (United States)

    Li, Yingxu; Li, Xiangyu; Kang, Guozheng; Gao, Yuanwen

    2016-10-01

    The anisotropy of critical current density is an impressive manifestation in the physics of high-temperature superconductors. We develop an analytical characterization of anisotropic flux-lattice pinning and critical current density in a system of random point defects. The effect of superconducting anisotropy on the pinning force and critical current density is formulated. The in-plane/out-of-plane anisotropy and microscopic characteristic lengths are incorporated in the field and angular dependence of the critical current density. This is helpful in understanding the physical essence of the scaling behavior in the experiments for critical current anisotropy. We discuss the role of strong and weak point defects in the anisotropic flux-lattice pinning. Relevance of the theory to the critical-state model is dictated as well.

  14. Critical reflections on the currently leading definition of sustainable employability.

    Science.gov (United States)

    Fleuren, Bram Bi; de Grip, Andries; Jansen, Nicole Wh; Kant, Imjert; Zijlstra, Fred Rh

    2016-06-01

    the labor market to maintain economic welfare (1). Moreover, as a consequence of population aging (2-6), longevity, rapid changes in technology (7, 8) and changes in the nature of work (1), both the need to promote sustainable employability of individuals in society and the complexity to succeed in doing so increase even further. Only recently, van der Klink et al provided the first definition of the concept in the international scientific literature (1, p74): "Sustainable employability means that throughout their working lives, workers can achieve tangible opportunities in the form of a set of capabilities. They also enjoy the necessary conditions that allow them to make a valuable contribution through their work, now and in the future, while safeguarding their health and welfare. This requires, on the one hand, a work context that facilitates this for them and, on the other, the attitude and motivation to exploit these opportunities." This definition is accompanied by an equally recent operationalization of SE as a set of capabilities (9). Moreover, the definition itself also appeared in an earlier Dutch publication (10), which other international publications about SE most commonly refer to [ie, in comparison with other definitions in the non-international (eg, Dutch) literature] (11-13). As mentioned, the present paper provides a critical reflection on van der Klink et al's aforementioned definition of SE (1). Merits Van der Klink et al's definition of SE (1) has three important merits. First, SE is seen as a multidimensional construct. It is presented as consisting of a broad set of opportunities for employees to create value for themselves and for their employer that cover various aspects of working. Moreover, the individual's health and well-being as well as attitudinal and motivational aspects are included in the definition as well. This acknowledgement of the multidimensionality of SE is favorable, as it illustrates the complexity of the construct and of what

  15. Current trends in developing medical students' critical thinking abilities.

    Science.gov (United States)

    Harasym, Peter H; Tsai, Tsuen-Chiuan; Hemmati, Payman

    2008-07-01

    Health care is fallible and prone to diagnostic and management errors. The major categories of diagnostic errors include: (1) no-fault errors--the disease is present but not detected; (2) system errors--a diagnosis is delayed or missed because of the imperfection in the health care system; and (3) cognitive errors--a misdiagnosis from faulty data collection or interpretation, flawed reasoning, or incomplete knowledge. Approximately one third of patient problems are mismanaged because of diagnostic errors. Part of the solution lies in improving the diagnostic skills and critical thinking abilities of physicians as they progress through medical school and residency training. However, this task is challenging since both medical problem-solving and the learning environments are complex and not easily understood. There are many interacting variables including the motivation of the medical student (e.g. deep versus surface learning), the acquisition and evolution of declarative and conditional knowledge (e.g. reduced, dispersed, elaborated, scheme, and scripted), problem-solving strategies (e.g. procedural knowledge-guessing, hypothetical deductive, scheme inductive, and pattern recognition), curricular models (e.g. apprenticeship, discipline-based, body system-based, case-based, clinical presentation-based), teaching strategies (e.g. teaching general to specific or specific to general), the presented learning opportunities (PBL versus scheme inductive PBL), and the nature of the learning environment (e.g. modeling critical thinking and expert problem-solving). This paper elaborates on how novices differ from experts and how novices can be educated in a manner that enhances their level of expertise and diagnostic abilities as they progress through several years of medical training.

  16. Local ecosystem feedbacks and critical transitions in the climate

    NARCIS (Netherlands)

    Rietkerk, M.; Brovkin, V.; Bodegom, van P.M.; Kabat, P.; Nes, van E.H.

    2011-01-01

    Global and regional climate models, such as those used in IPCC assessments, are the best tools available for climate predictions. Such models typically account for large-scale land-atmosphere feedbacks. However, these models omit local vegetation-environment feedbacks that may be crucial for

  17. The immutability of the critical current under any sample cross-sectional form modification

    Energy Technology Data Exchange (ETDEWEB)

    Bogolyubov, N.A. [Institute of Inorganic Chemistry Russian Academy of Sciences, Siberian Branch, Lavrent' eva 3, Novosibirsk 630090 (Russian Federation)], E-mail: bna@che.nsk.su

    2008-11-24

    The temperature and size dependences of the critical currents in bismuth-based high-temperature superconducting ceramic samples consisting of randomly oriented grains have been studied in zero magnetic field. It is shown that the critical current is a function of the sample cross-sectional area only. At constant sample cross-sectional area the value of the critical current is independent of any variation of a sample cross-sectional shape. At the same time the distributions of the critical current density and induced magnetic field in ceramics are functions of the sample cross-sectional shape. These values very in accordance with a change of the sample cross-sectional shape (at constant cross-sectional area i.e. at constant value of the critical current). The field and current distributions in the rectangular sample are reported.

  18. A new method for estimating the critical current density of a superconductor from its hysteresis loop

    Energy Technology Data Exchange (ETDEWEB)

    Lal, Ratan, E-mail: rlal_npl_3543@yahoo.i [Superconductivity Division, National Physical Laboratory, Council of Scientific and Industrial Research, Dr. K.S. Krishnan Road, New Delhi 110012 (India)

    2010-02-15

    The critical current density J{sub c} of some of the superconducting samples, calculated on the basis of the Bean's model, shows negative curvature for low magnetic field with a downward bending near H = 0. To avoid this problem Kim's expression of the critical current density, J{sub c} = k/(H{sub 0} + H), where J{sub c} has positive curvature for all H, has been employed by connecting the positive constants k and H{sub 0} with the features of the hysteresis loop of a superconductor. A relation between the full penetration field H{sub p} and the magnetic field H{sub min}, at which the magnetization is minimum, is obtained from the Kim's theory. Taking the value of J{sub c} at H = H{sub p} according to the actual loop width, as in the Bean's theory, and at H = 0 according to an enhanced loop width due to the local internal field, values of k and H{sub 0} are obtained in terms of the magnetization values M{sup +}(-H{sub min}), M{sup -}(H{sub min}), M{sup +}(H{sub p}) and M{sup -}(H{sub p}). The resulting method of estimating J{sub c} from the hysteresis loop turns out to be as simple as the Bean's method.

  19. Core Stability in Athletes: A Critical Analysis of Current Guidelines.

    Science.gov (United States)

    Wirth, Klaus; Hartmann, Hagen; Mickel, Christoph; Szilvas, Elena; Keiner, Michael; Sander, Andre

    2017-03-01

    Over the last two decades, exercise of the core muscles has gained major interest in professional sports. Research has focused on injury prevention and increasing athletic performance. We analyzed the guidelines for so-called functional strength training for back pain prevention and found that programs were similar to those for back pain rehabilitation; even the arguments were identical. Surprisingly, most exercise specifications have neither been tested for their effectiveness nor compared with the load specifications normally used for strength training. Analysis of the scientific literature on core stability exercises shows that adaptations in the central nervous system (voluntary activation of trunk muscles) have been used to justify exercise guidelines. Adaptations of morphological structures, important for the stability of the trunk and therefore the athlete's health, have not been adequately addressed in experimental studies or in reviews. In this article, we explain why the guidelines created for back pain rehabilitation are insufficient for strength training in professional athletes. We critically analyze common concepts such as 'selective activation' and training on unstable surfaces.

  20. Local quantum criticality of an iron-pnictide tetrahedron.

    Science.gov (United States)

    Ong, T Tzen; Coleman, Piers

    2012-03-01

    Motivated by the close correlation between transition temperature (T(c)) and the tetrahedral bond angle of the As-Fe-As layer observed in the iron-based superconductors, we study the interplay between spin and orbital physics of an isolated iron-arsenide tetrahedron embedded in a metallic environment. Whereas the spin-Kondo effect is suppressed to low temperatures by Hund's coupling, the orbital degrees of freedom are expected to quantum mechanically quench at high temperatures, giving rise to an overscreened, non-Fermi liquid ground state. Translated into a dense environment, this critical state may play an important role in the superconductivity of these materials.

  1. Detection of localized damage by eddy currents technique

    Directory of Open Access Journals (Sweden)

    Aoukili A.

    2014-01-01

    Full Text Available Non destructive evaluation techniques based on eddy currents (EC are largely used for quality control of the castings in a lot of industries. The principle of detection by EC consists in using an adequate inductive coil to generate them by a variable magnetic field, and measuring their effects by using one or several sensors. These effects result from the interaction between the induced magnetic field and the excited conductive material. A local variation of the physical properties or geometry of the tested sample, due to a singularity or a flaw, causes a modification of the EC distribution, enabling thus detection. In order to optimize the capacity of defect revealing by means of EC based probes, an accurate modelling of the problem is essential. This can be used to perform simulation of the EC distribution under different circumstances and to analyze the EC sensitivity to the various implicated parameters. In this work, the modelling of EC is made by using the finite element method. Using a B-scan strategy was used, detection of a small defect having the shape of an open cavity is shown to be correctly indicated via monitoring variations of the induced voltage in the receiver coil.

  2. Transport critical-current density of superconducting films with hysteretic ferromagnetic dots

    Directory of Open Access Journals (Sweden)

    Nuria Del-Valle

    2012-06-01

    Full Text Available Superconductor-ferromagnet hybrids present a rich and complex phenomenology. Particularly, a hysteretic behavior on the transport critical-current density, as a function of a uniform perpendicular applied field, has been experimentally found in superconducting films with some embedded ferromagnets. Here we analyze the interaction superconductor-ferromagnets by means of an iterative model based on the critical-state model with field-dependent internal critical-current density and compare the results with actual transport measurements. By using arguments of field compensation, we show how the change in the magnetization of the ferromagnetic inclusions is responsible for the observed hysteresis on the transport critical current.

  3. Low frequency critical current noise and two level system defects in Josephson junctions

    Science.gov (United States)

    Nugroho, Christopher Daniel

    The critical current in a Josephson junction is known to exhibit a 1/falpha low frequency noise. Implemented as a superconducting qubit, this low frequency noise can lead to decoherence. While the 1/f noise has been known to arise from an ensemble of two level systems connected to the tunnel barrier, the precise microscopic nature of these TLSs remain a mystery. In this thesis we will present measurements of the 1/f alpha low frequency noise in the critical current and tunneling resistance of Al-AlOx-Al Josephson junctions. Measurements in a wide range of resistively shunted and unshunted junctions confirm the equality of critical current and tunneling resistance noise. That is the critical current fluctuation corresponds to fluctuations of the tunneling resistance. In not too small Al-AlOx-Al junctions we have found that the fractional power spectral density scales linearly with temperature. We confirmed that the 1/falpha power spectrum is the result of a large number of two level systems modulating the tunneling resistance. At small junction areas and low temperatures, the number of thermally active TLSs is insufficient to integrate out a featureless 1/ f spectral shape. By analyzing the spectral variance in small junction areas, we have been able to deduce the TLS defect density, n ≈ 2.53 per micrometer squared per Kelvin spread in the TLS energy per factor e in the TLS lifetimes. This density is consistent with the density of tunneling TLSs found in glassy insulators, as well as the density deduced from coherent TLSs interacting at qubit frequencies. The deduced TLS density combined with the magnitude of the 1/f power spectral density in large area junctions, gives an average TLS effective area, A ˜ 0.3 nanometer squared. In ultra small tunnel junctions, we have studied the time-domain dynamics of isolated TLSs. We have found a TLS whose dynamics is described by the quantum tunneling between the two localized wells, and a one-phonon absorption

  4. Current anti-doping policy: a critical appraisal

    Directory of Open Access Journals (Sweden)

    Mauron Alexandre

    2007-03-01

    Full Text Available Abstract Background Current anti-doping in competitive sports is advocated for reasons of fair-play and concern for the athlete's health. With the inception of the World Anti Doping Agency (WADA, anti-doping effort has been considerably intensified. Resources invested in anti-doping are rising steeply and increasingly involve public funding. Most of the effort concerns elite athletes with much less impact on amateur sports and the general public. Discussion We review this recent development of increasingly severe anti-doping control measures and find them based on questionable ethical grounds. The ethical foundation of the war on doping consists of largely unsubstantiated assumptions about fairness in sports and the concept of a "level playing field". Moreover, it relies on dubious claims about the protection of an athlete's health and the value of the essentialist view that sports achievements reflect natural capacities. In addition, costly antidoping efforts in elite competitive sports concern only a small fraction of the population. From a public health perspective this is problematic since the high prevalence of uncontrolled, medically unsupervised doping practiced in amateur sports and doping-like behaviour in the general population (substance use for performance enhancement outside sport exposes greater numbers of people to potential harm. In addition, anti-doping has pushed doping and doping-like behaviour underground, thus fostering dangerous practices such as sharing needles for injection. Finally, we argue that the involvement of the medical profession in doping and anti-doping challenges the principles of non-maleficience and of privacy protection. As such, current anti-doping measures potentially introduce problems of greater impact than are solved, and place physicians working with athletes or in anti-doping settings in an ethically difficult position. In response, we argue on behalf of enhancement practices in sports within a

  5. Current anti-doping policy: a critical appraisal.

    Science.gov (United States)

    Kayser, Bengt; Mauron, Alexandre; Miah, Andy

    2007-03-29

    Current anti-doping in competitive sports is advocated for reasons of fair-play and concern for the athlete's health. With the inception of the World Anti Doping Agency (WADA), anti-doping effort has been considerably intensified. Resources invested in anti-doping are rising steeply and increasingly involve public funding. Most of the effort concerns elite athletes with much less impact on amateur sports and the general public. We review this recent development of increasingly severe anti-doping control measures and find them based on questionable ethical grounds. The ethical foundation of the war on doping consists of largely unsubstantiated assumptions about fairness in sports and the concept of a "level playing field". Moreover, it relies on dubious claims about the protection of an athlete's health and the value of the essentialist view that sports achievements reflect natural capacities. In addition, costly antidoping efforts in elite competitive sports concern only a small fraction of the population. From a public health perspective this is problematic since the high prevalence of uncontrolled, medically unsupervised doping practiced in amateur sports and doping-like behaviour in the general population (substance use for performance enhancement outside sport) exposes greater numbers of people to potential harm. In addition, anti-doping has pushed doping and doping-like behaviour underground, thus fostering dangerous practices such as sharing needles for injection. Finally, we argue that the involvement of the medical profession in doping and anti-doping challenges the principles of non-maleficience and of privacy protection. As such, current anti-doping measures potentially introduce problems of greater impact than are solved, and place physicians working with athletes or in anti-doping settings in an ethically difficult position. In response, we argue on behalf of enhancement practices in sports within a framework of medical supervision. Current anti

  6. Current and Emerging Detoxification Therapies for Critical Care

    Directory of Open Access Journals (Sweden)

    Brett A. Howell

    2010-04-01

    Full Text Available Toxicity resulting from prescription drugs such as tricyclic antidepressants and cardioactive steroids, as well as drugs of abuse and exposure to environmental chemicals, represents a major need for detoxification treatments. Particles and colloids, antibody fragments (Fab, and indirect treatment methods such as macroemulsions, are currently being developed or employed as detoxification therapies. Colloids, particles, and protein fragments typically mitigate toxicity by binding to the toxin and reducing its concentration in vital organs. Indirect methods such as macroemulsions and sodium bicarbonate act directly on the affected organs, rather than the toxin. In this review, key design parameters (i.e. binding affinity, biocompatibility, pharmacokinetics are discussed for each type of detoxification treatment. In addition, some of the latest research in each area is reviewed.

  7. Experience with current multiaxial diagnostic systems: a critical review.

    Science.gov (United States)

    Kastrup, Marianne

    2002-01-01

    It is difficult to capture the complexity of the psychiatric condition with a single diagnostic category, and a multiaxial approach provides a more comprehensive picture of the current disorder. The WPA section on classification has developed a multiaxial schema based on the ICD-10 family of classifications. Four axes are proposed. Axis I: on clinical disorders; axis II: on disabilities; axis III: on contextual factors, and axis IV: on quality of life. Even though the multiaxial approach has been widely taught and surveys report on its international acceptability, daily use by clinicians of the 'non-diagnostic' axes have till now been limited, despite expressed interest by the very same clinicians. The multiaxial formulation is still developing and transcultural experiences need to be gained.

  8. Analysis of distribution of critical current of bent-damaged Bi2223 composite tape

    Energy Technology Data Exchange (ETDEWEB)

    Ochiai, S; Okuda, H; Hojo, M [Graduate School of Engineering, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606- 8501 (Japan); Sugano, M [Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura, Nishikyo-ku, Kyoto 615-8530 (Japan); Osamura, K [Research Institute for Applied Sciences, Sakyo-ku, Kyoto 606-8202 (Japan); Kuroda, T; Kumakura, H; Kitaguchi, H; Itoh, K; Wada, H, E-mail: shojiro.ochiai@materials.mbox.media.kyoto-u.ac.jp [National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2011-10-29

    Distributions of critical current of damaged Bi2223 tape specimens bent by 0.6, 0.8 and 1.0% were investigated analytically with a modelling approach based on the correlation of damage evolution to distribution of critical current. It was revealed that the distribution of critical current is described by three parameter Weibull distribution function through the distribution of the tensile damage strain of Bi2223 filaments that determines the damage front in bent-composite tape. Also it was shown that the measured distribution of critical current values can be reproduced successfully by a Monte Carlo simulation using the distributions of tensile damage strain of filaments and original critical current.

  9. Critical analysis of biomarkers in the current periodontal practice.

    Science.gov (United States)

    Khiste, Sujeet V; Ranganath, V; Nichani, Ashish S; Rajani, V

    2011-04-01

    Periodontal disease is a chronic microbial infection that triggers inflammation-mediated loss of the periodontal ligament and alveolar bone that supports the teeth. Because of the increasing prevalence and associated comorbidities, there is a need for the development of new diagnostic tests that can detect the presence of active disease, predict future disease progression, and evaluate the response to periodontal therapy, thereby improving the clinical management of periodontal patients. The diagnosis of active phases of periodontal disease and the identification of patients at risk for active disease represent challenges for clinical investigators and practitioners. Advances in diagnostic research are moving toward methods whereby the periodontal risk can be identified and quantified by objective measures using biomarkers. Patients with periodontitis may have elevated circulating levels of specific inflammatory markers that can be correlated to the severity of the disease. Advances in the use of oral fluids as possible biological samples for objective measures of the current disease state, treatment monitoring, and prognostic indicators have boosted saliva- and other oral-based fluids to the forefront of technology. Gingival crevicular fluid (GCF) is an inflammatory exudate that can be collected at the gingival margin or within the gingival crevice. This article highlights recent advances in the use of biomarker-based disease diagnostics that focus on the identification of active periodontal disease from plaque biofilms, GCF, and saliva.

  10. Critical currents in A-15 structure Nb3Al converted from cold-worked bcc structure

    Science.gov (United States)

    Woollam, J. A.; Alterovitz, S. A.; Haugland, E.; Webb, G. W.

    1980-01-01

    The paper considers critical currents in A-15 structure Nb3Al converted from a cold-worked bcc structure. Nb3Al prepared in the ductile phase by quenching and mechanical working followed by conversion to the A-15 structure could carry currents above 10 to the 9th power A/sq m in fields near 20 T. These critical currents are comparable to those of Nb3Ge and V3Ga which are closest competing materials for use in high fields; further enhancement of the critical current is possible if thermal treatments are optimized.

  11. Frequency-dependent critical current and transport ac loss of superconductor strip and Roebel cable

    Energy Technology Data Exchange (ETDEWEB)

    Thakur, Kailash Prasad [Landcare Research, Palmerston North 4442 (New Zealand); Raj, Ashish [Computer Science in Radiology, Weill Medical College, Cornell University, NY 10022 (United States); Brandt, Ernst Helmut [Max-Planck-Institut fuer Metallforschung, PO B 800665, D-70506 Stuttgart (Germany); Kvitkovic, Jozef; Pamidi, Sastry V, E-mail: thakurk@landcareresearch.co.nz, E-mail: asr2004@med.cornell.edu, E-mail: ehb@mf.mpg.de, E-mail: kvitkovic@caps.fsu.edu, E-mail: pamidi@caps.fsu.edu [Center for Advanced Power System, Florida State University, Tallahassee, FL 32310 (United States)

    2011-06-15

    The frequency-dependent critical current of a superconductor strip and Roebel cable has been studied using a 2D finite element simulation. It is shown that the critical current of the superconductor increases with frequency as f{sup 1/n}, where n is the exponent of the power law flux creep model. Transport ac loss in a superconductor strip decreases with frequency as f{sup -2/n} when the amplitude of the applied ac current is far less than its critical current. However, when the applied current is large and becomes comparable to the critical current, the transport ac loss decreases with frequency as 1/f. The analytical results are substantiated with available experimental data and the results of a 2D finite element simulation.

  12. Dipolar field effects on the critical current for spin transfer switch of iron and permalloy nanoelements

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, L. L.; Dantas, J. T. S.; Souza, R. M.; Carriço, A. S., E-mail: ascarrico@gmail.com [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Dantas, Ana L. [Departamento de Física, Universidade do Estado do Rio Grande do Norte, 59610-210 Mossoró, RN (Brazil)

    2014-05-07

    We report a theoretical study of dipolar effects on the switching current density of soft ferromagnetic elliptical nanoelements. Relevant changes on the critical current value are found according to the orientation of the magnetization and the spin polarization with the major axis. We show that the critical current density may be reduced by as much as 92% for thin nanoelements magnetized along the minor axis direction, using in-plane spin polarization parallel to the magnetization.

  13. LOCAL ANAESTHETIC SYSTEMIC TOXICITY: CURRENT CONCEPTS AND MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Lakshmi

    2014-03-01

    Full Text Available Local anesthetics are one of the most commonly used drugs in the field of medicine. Local anesthetics are widely used to induce anesthesia and analgesia for surgical procedures and pain management. Local an aesthetic systemic toxicity (LAST is a rare but potentially fatal complication of regional anesthesia and has been recognized and reported since the late1800s. This narrative review summarizes the pharmacology of local anesthetics, clinical manifestations of systemic toxicity associated with these agents, necessary preventive measures and recent treatment strategies

  14. Spatially localized attacks on interdependent networks: the existence of a finite critical attack size

    CERN Document Server

    Berezin, Yehiel; Danziger, Michael M; Li, Daqing; Havlin, Shlomo

    2013-01-01

    Many real world complex systems such as infrastructure, communication and transportation networks are embedded in space, where entities of one system may depend on entities of other systems. These systems are subject to geographically localized failures due to malicious attacks or natural disasters. Here we study the resilience of a system composed of two interdependent spatially embedded networks to localized geographical attacks. We find that if an attack is larger than a finite (zero fraction of the system) critical size, it will spread through the entire system and lead to its complete collapse. If the attack is below the critical size, it will remain localized. In contrast, under random attack a finite fraction of the system needs to be removed to initiate system collapse. We present both numerical simulations and a theoretical approach to analyze and predict the effect of local attacks and the critical attack size. Our results demonstrate the high risk of local attacks on interdependent spatially embedd...

  15. LOCAL BUDGETS UNDER CURRENT DECENTRALIZATION: UKRAINE AND FOREIGN EXPERIENCE

    Directory of Open Access Journals (Sweden)

    O. Cheberyako

    2016-04-01

    Full Text Available The article is devoted to the major trends and issues of development of local budgets in Ukraine. A study of the essence of fiscal decentralization as one of the components of the management, aimed at reducing the dependence of local governments from the central government with regard to foreign experience. Particular attention is paid to local budgets under decentralization of own and delegated financial powers. The theoretical principles of fiscal decentralization and its proven impact on the socio-economic development. Studied the European countries model of local budgets. The features of formation of revenues of local budgets under decentralization. The role in shaping tax revenues of local budgets in foreign countries and Ukraine. The analysis of state policy of financial support for regional development in Ukraine. The structure of tax revenue in the context of changes in the budget and tax legislation in a decentralized tax powers. Systematized features of fiscal decentralization in Ukraine. Problems and grounded main ways of optimizing the formation of local budgets in a decentralized tax powers. Formed selection of areas targeted as ways to increase economic and financial independence of regions of Ukraine.

  16. A Quantitative Study of Critical Thinking Skills amongst Local Emergency Managers

    Science.gov (United States)

    Peerbolte, Stacy L.

    2010-01-01

    Emergency managers must be able to think critically to identify and anticipate situations, solve problems, and make judgments and decisions to effectively and efficiently assume and manage risks. An assessment of the extent to which local emergency managers are able to think critically has not yet been conducted. Based in systems theory and the…

  17. Method for determining transport critical current densities and flux penetration depth in bulk superconductors

    Science.gov (United States)

    Israelsson, Ulf E. (Inventor); Strayer, Donald M. (Inventor)

    1992-01-01

    A contact-less method for determining transport critical current density and flux penetration depth in bulk superconductor material. A compressor having a hollow interior and a plunger for selectively reducing the free space area for distribution of the magnetic flux therein are formed of superconductor material. Analytical relationships, based upon the critical state model, Maxwell's equations and geometrical relationships define transport critical current density and flux penetration depth in terms of the initial trapped magnetic flux density and the ratio between initial and final magnetic flux densities whereby data may be reliably determined by means of the simple test apparatus for evaluating the current density and flux penetration depth.

  18. Parental Photography at School Events: Current Local Authority Best Practice

    OpenAIRE

    Bessant, Claire

    2015-01-01

    An analysis of local authority policy and guidance on parental photography at school events considering possible policy content and approaches to informing parents of policy/obtaining parental consent.

  19. Direct Current and Pulsed Direct Current Plasma Nitriding of Ferrous Materials a Critical Review

    Directory of Open Access Journals (Sweden)

    Łępicka Magdalena

    2016-06-01

    Full Text Available Nowadays, the improvement of ferrous materials performance is a problem of high interest. One of well-known wear- and corrosion properties improving technique is plasma nitriding, in which elemental nitrogen is introduced to the surface of a metal part for subsequent diffusion into the material. As a result, a compound, “white” layer and a diffusion zone are formed at the detail’s surface. Most of the authors positively describe the effects of surface ion nitiding. On the other hand, there are also reports on adverse effects of direct current and pulsed direct current plasma nitriding on ferrous materials performance. Therefore, an attempt to provide comprehensive summary on direct current and pulsed direct current ion nitriding and its influence on ferrous materials’ mechanical and corrosion properties has been made. According to the results, some of the technique drawbacks are hard to avoid in mass production.

  20. Influence of Fast Neutron Irradiation on Critical Current Densities of Bi-2223/Ag Tape

    Institute of Scientific and Technical Information of China (English)

    Duan Zhenzhong

    2004-01-01

    Experimental results on the magnetic field behavior of the critical current in silver sheathed Bi-2223 tapes are presented. The experiments consist of transport and magnetic measurements in a wide temperature range and in external magnetic field up to 6 T. Significant enhancement of the intragrain critical current densities Jc are observed after irradiation with fast neutron. This is attributed to an improvement of flux pinning capability by the neutron induced defects, but the weak link structure is somewhat damaged as evidenced by the small degradation of transport critical current at low field. According to the measurement of remanent magnetic moment before and after irradiation with fast neutron, the connectivity in Bi-2223 tapes is reduced by 50% after irradiated to a fluence of 2 × 1021 m-2, which resulted in the critical currents degradated by a factor of 10%.

  1. Effect of hexagonal patterned arrays and defect geometry on the critical current of superconducting films

    CERN Document Server

    Sadovskyy, I A; Xiao, Z -L; Kwok, W -K; Glatz, A

    2016-01-01

    Understanding the effect of pinning on the vortex dynamics in superconductors is a key factor towards controlling critical current values. Large-scale simulations of vortex dynamics can provide a rational approach to achieve this goal. Here, we use the time-dependent Ginzburg-Landau equations to study thin superconducting films with artificially created pinning centers arranged periodically in hexagonal lattices. We calculate the critical current density for various geometries of the pinning centers --- varying their size, strength, and density. Furthermore, we shed light upon the influence of pattern distortion on the magnetic field dependent critical current. We compare our result directly with available experimental measurements on patterned molybdenum-germanium films, obtaining good agreement. Our results give important systematic insights into the mechanisms of pinning in these artificial pinning landscapes and open a path for tailoring superconducting films with desired critical current behavior.

  2. Effect of hexagonal patterned arrays and defect geometry on the critical current of superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Sadovskyy, I. A.; Wang, Y. L.; Xiao, Z. -L.; Kwok, W. -K.; Glatz, A.

    2017-02-07

    Understanding the effect of pinning on the vortex dynamics in superconductors is a key factor towards controlling critical current values. Large-scale simulations of vortex dynamics can provide a rational approach to achieve this goal. Here, we use the time-dependent Ginzburg-Landau equations to study thin superconducting films with artificially created pinning centers arranged periodically in hexagonal lattices. We calculate the critical current density for various geometries of the pinning centers—varying their size, strength, and density. Furthermore, we shed light upon the influence of pattern distortion on the magnetic-field-dependent critical current. We compare our result directly with available experimental measurements on patterned molybdenum-germanium films, obtaining good agreement. Our results give important systematic insights into the mechanisms of pinning in these artificial pinning landscapes and open a path for tailoring superconducting films with desired critical current behavior.

  3. Enhancement of critical current in mesoscopic superconducting strips by external magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Ilin, Konstantin; Henrich, Dagmar; Luck, Yannick; Fuchs, Lea; Meckbach, Johannes Maximilian; Siegel, Michael [Institut fuer Mikro- und Nanoelektronische Systeme, Karlsruher Institut fuer Technologie, Hertzstrasse 16, 76187 Karlsruhe (Germany)

    2013-07-01

    Current crowding in superconducting mesoscopic strips with bends results in decrease of critical current in these structures with respect to the strips without geometrical non-uniformities. Recently it has been shown that Meissner currents induced by externally applied magnetic field of appropriate direction allow to suppress this effect so that I{sub c}(B) can exceed I{sub c}(0). Experimental dependencies of critical current in mesoscopic bended strips made from ultra-thin superconducting films on externally applied magnetic field and their comparison to the theoretical predictions are presented and discussed.

  4. Global and Local Approaches Describing Critical Phenomena on the Developing and Developed Financial Markets

    Science.gov (United States)

    Grech, Dariusz

    We define and confront global and local methods to analyze the financial crash-like events on the financial markets from the critical phenomena point of view. These methods are based respectively on the analysis of log-periodicity and on the local fractal properties of financial time series in the vicinity of phase transitions (crashes). The log-periodicity analysis is made in a daily time horizon, for the whole history (1991-2008) of Warsaw Stock Exchange Index (WIG) connected with the largest developing financial market in Europe. We find that crash-like events on the Polish financial market are described better by the log-divergent price model decorated with log-periodic behavior than by the power-law-divergent price model usually discussed in log-periodic scenarios for developed markets. Predictions coming from log-periodicity scenario are verified for all main crashes that took place in WIG history. It is argued that crash predictions within log-periodicity model strongly depend on the amount of data taken to make a fit and therefore are likely to contain huge inaccuracies. Next, this global analysis is confronted with the local fractal description. To do so, we provide calculation of the so-called local (time dependent) Hurst exponent H loc for the WIG time series and for main US stock market indices like DJIA and S&P 500. We point out dependence between the behavior of the local fractal properties of financial time series and the crashes appearance on the financial markets. We conclude that local fractal method seems to work better than the global approach - both for developing and developed markets. The very recent situation on the market, particularly related to the Fed intervention in September 2007 and the situation immediately afterwards is also analyzed within fractal approach. It is shown in this context how the financial market evolves through different phases of fractional Brownian motion. Finally, the current situation on American market is

  5. Local Helioseismology of Sunspots: Current Status and Perspectives (Invited Review)

    CERN Document Server

    Kosovichev, A G

    2010-01-01

    Mechanisms of formation and stability of sunspots are among the longest-standing and intriguing puzzles of solar physics and astrophysics. Sunspots are controlled by subsurface dynamics hidden from direct observations. Recently, substantial progress in our understanding of physics of the turbulent magnetized plasma has been made by numerical simulations and local helioseismology. Both, the simulations and helioseismic measurements, are extremely challenging, but it becomes clear that the key to understanding the enigma of sunspots is a synergy between models and observations. Recent observations and radiative MHD numerical simulations have provided a convincing explanation to the Evershed flows in sunspot penumbra. Also, they lead to the understanding of sunspots as self-organized magnetic structures in the turbulent plasma of the upper convection zone, which are maintained by a large-scale dynamics. Local helioseismic diagnostics of sunspots still have many uncertainties, some of which are discussed in this ...

  6. On a common critical state in localized and diffuse failure modes

    Science.gov (United States)

    Zhu, Huaxiang; Nguyen, Hien N. G.; Nicot, François; Darve, Félix

    2016-10-01

    Accurately modeling the critical state mechanical behavior of granular material largely relies on a better understanding and characterizing the critical state fabric in different failure modes, i.e. localized and diffuse failure modes. In this paper, a mesoscopic scale is introduced, in which the organization of force-transmission paths (force-chains) and cells encompassed by contacts (meso-loops) can be taken into account. Numerical drained biaxial tests using a discrete element method are performed with different initial void ratios, in order to investigate the critical state fabric on the meso-scale in both localized and diffuse failure modes. According to the displacement and strain fields extracted from tests, the failure mode and failure area of each specimen are determined. Then convergent critical state void ratios are observed in failure area of specimens. Different mechanical features of two kinds of meso-structures (force-chains and meso-loops) are investigated, to clarify whether there exists a convergent meso-structure inside the failure area of granular material, as the signature of critical state. Numerical results support a positive answer. Failure area of both localized and diffuse failure modes therefore exhibits the same fabric in critical state. Hence, these two failure modes prove to be homological with respect to the concept of the critical state.

  7. Critical behaviour of the local magnetic susceptibility in a ferromagnetic film

    Science.gov (United States)

    Korneta, W.; Pytel, Z.

    1985-07-01

    The nearest-neighbour Ising model of a ferromagnetic film in which couplings between surface spins may differ from couplings between remaining spins is considered. Using the mean-field approximation, the local magnetic susceptibility defined as the derivative of the local magnetization with respect to the external uniform magnetic field is obtained. The behaviour of the local magnetic susceptibility near the ordinary, surface-bulk and surface phase transitions and in a range of temperatures where physical quantities have pseudocritical behaviour is discussed. The critical behaviour of the local magnetic susceptibility in a three-dimensional semi-infinite model is also given for comparison.

  8. Effect of longitudinal applied magnetic field on the self-pinched critical current in intense electron beam diode

    Institute of Scientific and Technical Information of China (English)

    Liu Guo-Zhi; Huang Wen-Hua; Shao Hao; Xiao Ren-Zhen

    2006-01-01

    The effect of applied longitudinal magnetic field on the self-pinched critical current in the intense electron beam diode is discussed. The self-pinched critical current is derived and its validity is tested by numerical simulations. The results shows that an applied longitudinal magnetic field tends to increase the self-pinched critical current. Without the effect of anode plasma, the maximal diode current approximately equals the self-pinched critical current with the longitudinal magnetic field applied; when self-pinched occurs, the diode current approaches the self-pinched critical current.

  9. Flux quantum tunneling effect and its influence on the experimental critical current density

    Institute of Scientific and Technical Information of China (English)

    闻海虎; 赵忠贤; GriessenR.

    1995-01-01

    By using magnetic sweeping method, the temperature and magnetic field dependencies of the experimental current density and the normalized relaxation rate have been obtained. The true critical current density corresponding to the zero activation energy has been carried out based on the collective-pinning and the thermally-activated flux motion models, and therefore the influences of the quantum tunneling effect and the thermal activation effect on the experimental critical current density are distinguished. It is found that, with temperature lower than 10 K, the relaxation rate will not drop to zero when T approaches zero K because of the occurrence of the flux quantum tunneling. This additional flux motion further reduces the experimental critical current density j making it saturated with lowering temperature.

  10. Magnetic Field Dependence of the Critical Current in S-N Bilayer Thin Films

    Science.gov (United States)

    Sadleir, John E.; Lee, Sang-Jun; Smith, Stephen James; Bandler, Simon; Chervenak, James; Kilbourne, Caroline A.; Finkbeiner, Fred M.; Porter, Frederick S.; Kelley, Richard L.; Adams, Joseph S.; Eckart, Megan E.; Busch, Sarah; Porst, Jan-Patrick

    2013-01-01

    Here we investigate the effects a non-uniform applied magnetic field has on superconducting transition-edge sensors (TESs) critical current. This has implications on TES optimization. It has been shown that TESs resistive transition can be altered by magnetic fields. We have observed critical current rectification effects and explained these effects in terms of a magnetic self-field arising from asymmetric current injection into the sensor. Our TES physical model shows that this magnetic self-field can result in significantly degraded or improved TES performance. In order for this magnetically tuned TES strategy to reach its full potential we are investigating the effect a non-uniform applied magnetic field has on the critical current.

  11. High critical current densities in industrial scale composites made from high homogeneity NB 46. 5 TI

    Energy Technology Data Exchange (ETDEWEB)

    Larbalestier, D.C.; Hemachalam, K.; Lee, P.; McDonald, W.K.; O' Larey, P.; Scanlan, R.; Starch, W.; Taylor, C.; Warnes, W.; West, A.W.; Zeitlin, B.

    1985-03-01

    Recent work in our group on the fabricationmicrostructure-superconducting properties of composites of Nb-Ti has produced much new information about the precipitate morphology and origins of high critical current density (J /SUB c/ ) in these materials./sup 1 -4/ Precipitation of Ti-rich phase is seen to commence as a grain boundary film 2 - 4 nm thick, the film then developing into approximately equiaxed particles of ..cap alpha..-Ti at the boundary triple points. The typical size of such precipitates is 50 - 100 nm. Controlled drawing of such a structure produces an array of locally ordered ribbon precipitates. These precipitates are typically 3 - 5 nm thick by 100 - 300 nm long (when observed in transverse section). Their length in longitudinal section appears to be several hundred nm, indicating great ductility in these small ..cap alpha..-Ti precipitates. The typical separation of the precipitates is 20 - 30 nm. Thus the dimensions of the precipitate array are quite comparable to that of the flux lattice since the fluxoid separation is 22 nm at 5 T and the fluxoid diameter of Nb 46.5 wt% Ti is approximately 10 nm. The flux pinning behavior of these precipitate structures is expected to be complex: /SUP 2.4/ the defect density is very high, the precipitate morphology has a very high aspect ratio and the extreme thinness of the precipitates must permit some superconductivity to be induced in them by the proximity effect./sup 5/

  12. Local Classical and Quantum Criticality due to Electron-Vibration Interaction

    OpenAIRE

    2009-01-01

    We study the local classical and quantum critical properties of electron-vibration interaction, represented by the Yu-Anderson model. It exhibits an instability, similar to the Wentzel-Bardeen singularity, whose nature resembles to weakly first order quantum phase transitions at low temperatures, and crosses over to Gaussian behaviour with increasing temperature. We determine the dominant energy scale separating the quantum from classical criticality, study the effect of dissipation and analy...

  13. Critical adsorption profiles around a sphere and a cylinder in a fluid at criticality: Local functional theory

    Science.gov (United States)

    Yabunaka, Shunsuke; Onuki, Akira

    2017-09-01

    We study universal critical adsorption on a solid sphere and a solid cylinder in a fluid at bulk criticality, where preferential adsorption occurs. We use a local functional theory proposed by Fisher et al. [M. E. Fisher and P. G. de Gennes, C. R. Acad. Sci. Paris Ser. B 287, 207 (1978); M. E. Fisher and H. Au-Yang, Physica A 101, 255 (1980), 10.1016/0378-4371(80)90112-0]. We calculate the mean order parameter profile ψ (r ) , where r is the distance from the sphere center and the cylinder axis, respectively. The resultant differential equation for ψ (r ) is solved exactly around a sphere and numerically around a cylinder. A strong adsorption regime is realized except for very small surface field h1, where the surface order parameter ψ (a ) is determined by h1 and is independent of the radius a . If r considerably exceeds a , ψ (r ) decays as r-(1 +η ) for a sphere and r-(1 +η )/2 for a cylinder in three dimensions, where η is the critical exponent in the order parameter correlation at bulk criticality.

  14. High magnetic-field scales and critical currents in SmFeAs(O, F) crystals

    Science.gov (United States)

    Moll, Philip J. W.; Puzniak, Roman; Balakirev, Fedor; Rogacki, Krzysztof; Karpinski, Janusz; Zhigadlo, Nikolai D.; Batlogg, Bertram

    2010-08-01

    With the discovery of new superconducting materials, such as the iron pnictides, exploring their potential for applications is one of the foremost tasks. Even if the critical temperature Tc is high, intrinsic electronic properties might render applications difficult, particularly if extreme electronic anisotropy prevents effective pinning of vortices and thus severely limits the critical current density, a problem well known for cuprates. Although many questions concerning microscopic electronic properties of the iron pnictides have been successfully addressed and estimates point to a very high upper critical field, their application potential is less clear. Thus, we focus here on the critical currents, their anisotropy and the onset of electrical dissipation in high magnetic fields up to 65T. Our detailed study of the transport properties of SmFeAsO0.7F0.25 single crystals reveals a promising combination of high (>2×106Acm-2) and nearly isotropic critical current densities along all crystal directions. This favourable intragrain current transport in SmFeAs(O, F), which shows the highest Tc of 54K at ambient pressure, is a crucial requirement for possible applications. Essential in these experiments are four-probe measurements on focused-ion-beam-cut single crystals with a sub-square-micrometre cross-section, with current along and perpendicular to the crystallographic c axis.

  15. Local and cluster critical dynamics of the 3d random-site Ising model

    Science.gov (United States)

    Ivaneyko, D.; Ilnytskyi, J.; Berche, B.; Holovatch, Yu.

    2006-10-01

    We present the results of Monte Carlo simulations for the critical dynamics of the three-dimensional site-diluted quenched Ising model. Three different dynamics are considered, these correspond to the local update Metropolis scheme as well as to the Swendsen-Wang and Wolff cluster algorithms. The lattice sizes of L=10-96 are analysed by a finite-size-scaling technique. The site dilution concentration p=0.85 was chosen to minimize the correction-to-scaling effects. We calculate numerical values of the dynamical critical exponents for the integrated and exponential autocorrelation times for energy and magnetization. As expected, cluster algorithms are characterized by lower values of dynamical critical exponent than the local one: also in the case of dilution critical slowing down is more pronounced for the Metropolis algorithm. However, the striking feature of our estimates is that they suggest that dilution leads to decrease of the dynamical critical exponent for the cluster algorithms. This phenomenon is quite opposite to the local dynamics, where dilution enhances critical slowing down.

  16. Locally converging algorithms for determining the critical temperature in Ising systems

    Science.gov (United States)

    Faraggi, Eshel; Robb, Daniel T.

    2008-10-01

    We introduce a class of algorithms that converge to criticality automatically, in a way similar to the invaded cluster algorithm. Unlike the invaded cluster algorithm which uses global percolation as a test for criticality, these local algorithms use an average over local observables, specifically the number of satisfied bonds, in a feedback loop which drives the system toward criticality. Two specific algorithms are introduced, the average algorithm and the locally converging Wolff algorithm. We apply these algorithms to study the Ising square lattice and the Ising Bethe lattice. We find reasonable convergence to the critical temperature for both systems under the locally converging Wolff algorithm. We also re-examine the phase diagram of the dilute two-dimensional (2D) Ising model and find results supporting our previously reported conclusions regarding the existence of a local regime of magnetization below the percolations threshold. In addition, the presented algorithms are computationally more efficient than the invaded cluster algorithm, requiring less CPU time and memory.

  17. Prediction of Critical Currents for a Diluted Square Lattice Using Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Sajjad Ali Haider

    2017-03-01

    Full Text Available Studying critical currents, critical temperatures, and critical fields carries substantial importance in the field of superconductivity. In this work, we study critical currents in the current–voltage characteristics of a diluted-square lattice on an Nb film. Our measurements are based on a commercially available Physical Properties Measurement System, which may prove time consuming and costly for repeated measurements for a wide range of parameters. We therefore propose a technique based on artificial neural networks to facilitate extrapolation of these curves for unforeseen values of temperature and magnetic fields. We demonstrate that our proposed algorithm predicts the curves with an immaculate precision and minimal overhead, which may as well be adopted for prediction in other types of regular and diluted lattices. In addition, we present a detailed comparison between three artificial neural networks architectures with respect to their prediction efficiency, computation time, and number of iterations to converge to an optimal solution.

  18. 3-Terminal pMTJ reduces critical current and switching time

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Lanting [Department of Electrical Engineering, University of California, Riverside, CA 92521 (United States); Khizroev, Sakhrat [Department of Electrical Engineering, Florida International University, Miami, FL 33174 (United States); Liang, Ping [Department of Electrical Engineering, University of California, Riverside, CA 92521 (United States)

    2014-05-01

    To realize the potential of magnetic tunnel junctions (MTJs) for high-density non-volatile memory and non-volatile logic, the critical current to switch the magnetization must be lowered. This paper presents a simulation study of a new structure of perpendicular MTJs (pMTJs) which divides the fixed layer into two coupling parts. We investigate the TMR and the critical current density of this new pMTJ by micromagnetic simulation using OOMMF for various cases. The simulation results show that this new structure pMTJ has lower critical current and shorter switching time compared to the conventional three-layer MTJs. - Highlights: • We investigate the factors which may affect the critical current density. • A new structure of 3-ternimal perpendicular MTJ is proposed which can switch between two states without changing the direction of the induced current. • Energy consumed will be lowered since a relatively low induced current density is needed. • The switching time between different states is shorter than conventional perpendicular MTJs.

  19. Health content in local television news: a current appraisal.

    Science.gov (United States)

    Wang, Zheng; Gantz, Walter

    2010-04-01

    While local television news remains an important channel for the dissemination of health information, there has been little systematic examination of health content on those newscasts. This study, designed to update and expand upon earlier efforts, examined 1,382.5 hours of newscasts that aired on seven channels in four markets between December 2004 and June 2005. The four markets were a major-, a large-, a medium-, and a small-size market in the Midwestern United States. In total, 40,112 news stories were coded. About 8.1% of the news stories were devoted to health content. Health stories covered a large array of topics. Physical illnesses/diseases and healthy living issues received the most frequent coverage, while mental health and aging-related content were covered least frequently. Most health stories were neutral in tone and rather brief, with an average duration of less than 1 minute. One in eight (12.4%) health stories provided follow-up options. This is primarily due to an increase in the number of health news stories presented with a website URL compared to previous findings. Market differences emerged, although, interestingly, stations in the larger markets were not the leaders in health coverage.

  20. ['I'm worthless' and other forms of self-criticism: Current knowledge and therapeutic interventions].

    Science.gov (United States)

    Maillard, Pauline; Kramer, Ueli

    2015-01-01

    Self-criticism is considered as a harsh or punitive evaluation of the self. It is omnipresent in culture, in daily life as well as in psychotherapy. Self-criticism can lead to question oneself but can also open new perspectives and guide us. However, it can become excessive, rigid, and might turn out to be deleterious. This present article focuses on the concept of self-criticism in clinical psychology and psychotherapy and aims to review current knowledge about this topic. First, its definition and the reasons for its development in individuals will be presented. Second, a description of the links between self-criticism and psychopathology will be made, in particular regarding depression. Finally, the third part of this article will be dedicated to the therapeutic interventions that can reduce self-criticism.

  1. Current Trends in Local Policing Provision in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Oldřich Krulík

    2014-12-01

    Full Text Available The paper examines the current trends of national police forces as they increasingly often pull back from their positions, and the consequences which many municipal councils in the Czech Republic are now facing. In the last couple of years, some municipalities chose relatively unconventional ways to deal with increased levels of crime and other forms of antisocial behaviour on their territories. This created space – for example – for signing public agreements with other municipalities, hiring private security companies to perform the role of municipal police or various forms of sponsoring the Police of the Czech Republic.

  2. Calibration of Hall sensor array for critical current measurement of YBCO tape with ferromagnetic substrate

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yunpeng; Wang, Gang; Liu, Liyuan [Key laboratory of Magnetic levitation Technologies and Maglev Trains (Ministry of Education), Superconductor and New Energy R& D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, 610031 (China); Yang, Xinsheng, E-mail: xsyang@swjtu.edu.cn [Key laboratory of Magnetic levitation Technologies and Maglev Trains (Ministry of Education), Superconductor and New Energy R& D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, 610031 (China); Zhao, Yong [Key laboratory of Magnetic levitation Technologies and Maglev Trains (Ministry of Education), Superconductor and New Energy R& D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, 610031 (China); Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney 2052, NSW (Australia)

    2015-12-15

    Abstract : HAS (Hall sensor array) is a powerful tool to detect the uniformity of HTS (high temperature superconductor) tape through mapping the distribution of remanent or shielding field along the surface of the tape. However, measurement of HTS tape with ferromagnetic parts by HSA is still an issue because the ferromagnetic substrate has influence on the magnetic field around the HTS layer. In this work, a continuous HSA system has been designed to measure the critical current of the YBCO tape with ferromagnetic substrate. The relationship between the remanent field and critical current was calibrated by the finite element method. The result showed that the HSA is an effective method for evaluating the critical current of the HTS tape with ferromagnetic substrate. - Highlight: • A continuous Hall sensor array system has been designed. • The inhomogeneity of YBCO tape with ferromagnetic substrate can be detected by HAS. • Finite element method is an effective method for calibrating the remanent field.

  3. Magnetic response and critical current properties of mesoscopic-size YBCO superconducting samples

    Energy Technology Data Exchange (ETDEWEB)

    Lisboa-Filho, P N [UNESP - Universidade Estadual Paulista, Grupo de Materiais Avancados, Departamento de Fisica, Bauru (Brazil); Deimling, C V; Ortiz, W A, E-mail: plisboa@fc.unesp.b [Grupo de Supercondutividade e Magnetismo, Departamento de Fisica, Universidade Federal de Sao Carlos, Sao Carlos (Brazil)

    2010-01-15

    In this contribution superconducting specimens of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} were synthesized by a modified polymeric precursor method, yielding a ceramic powder with particles of mesoscopic-size. Samples of this powder were then pressed into pellets and sintered under different conditions. The critical current density was analyzed by isothermal AC-susceptibility measurements as a function of the excitation field, as well as with isothermal DC-magnetization runs at different values of the applied field. Relevant features of the magnetic response could be associated to the microstructure of the specimens and, in particular, to the superconducting intra- and intergranular critical current properties.

  4. Change of surface critical current in the surface superconductivity and mixed states of superconducting niobium

    Science.gov (United States)

    Aburas, Muhamad; Pautrat, Alain; Bellido, Natalia

    2017-01-01

    A systematic study of irreversible magnetization was performed in bulk niobium after different surface treatments. Starting with smooth surfaces and abrading them, a strong increase of the critical current is observed up to an apparent limiting value. An impressive change of the critical current is also observed in the surface superconductivity (SSC) state, reaching values of the same order of magnitude as in the mixed state. We explain also the observation of strong SSC for magnetic fields perpendicular to large facets in terms of nucleation of superconductivity along bumps of a corrugated surface.

  5. Weak Centers and Local Bifurcations of Critical Periods at Infinity for a Class of Rational Systems

    Institute of Scientific and Technical Information of China (English)

    Wen-tao HUANG; Valery G. ROMANOVSKI; WEI-NIAN ZHANG

    2013-01-01

    We describe an approach to studying the center problem and local bifurcations of critical periods at infinity for a class of differential systems.We then solve the problem and investigate the bifurcations for a class of rational differential systems with a cubic polynomial as its numerator.

  6. Gauging the Potential of Socially Critical Environmental Education (EE): Examining Local Environmental Problems through Children's Perspective

    Science.gov (United States)

    Tsoubaris, Dimitris; Georgopoulos, Aleksandros

    2013-01-01

    The objective of this qualitative research work is to detect the needs, aspirations and feelings of pupils experiencing local environmental problems and elaborate them through the prism of a socially critical educational approach. Semi-structured focus group interviews are used as a research method applied to four primary schools located near…

  7. 'Leak Current' correction for critical current measurement of no-insulation HTS coil

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jung Bin [Laboratoire National des Champs Magnétiques Intenses, CNRS, Grenoble (France); Hahn, Seung Yong [Dept. of Electrical and Computer Engineering, Seoul National University, Seoul (Korea, Republic of)

    2017-06-15

    Discrepancy between a power supply current and an actual “spiral” coil current makes the conventional 4-probe measurement of a critical current (I{sub c}) of a no-insulation (NI) high temperature superconductor (HTS) coil inaccurate and time-consuming. This paper presents a fast and accurate approach for I{sub c} measurement of NI HTS coils. With an NI HTS coil energized at a constant ramping rate, a complete analytic expression for the spiral coil current was obtained from a first-order partial differential equation that derived from an equivalent circuit model of the NI coil. From the analytic solution, both spiral coil current and radial leak current can be obtained simultaneously, which enables fast and accurate measurement of the NI coil I{sub c}. To verify the proposed approach, an NI double-pancake (DP) coil, wound with GdBCO tapes of 6 mm × 0.1 mm, was constructed and its Ic was repeatedly measured with various ramping rates in a bath of liquid nitrogen at 77 K. The measured results agreed well with the calculated ones, which validates the proposed approach to measure I{sub c} of an NI HTS coil.

  8. 24 CFR 1000.320 - How is Formula Current Assisted Stock adjusted for local area costs?

    Science.gov (United States)

    2010-04-01

    ... § 1000.320 How is Formula Current Assisted Stock adjusted for local area costs? There are two adjustment... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false How is Formula Current Assisted Stock adjusted for local area costs? 1000.320 Section 1000.320 Housing and Urban Development...

  9. Critical current studies on fine filamentary NbTi accelerator wires

    Energy Technology Data Exchange (ETDEWEB)

    Garber, M.; Suenaga, M.; Sampson, W.B.; Sabatini, R.L.

    1985-01-01

    The magnets for the Superconductig Super Collider, a high energy proton colliding beam accelerator, require a superconductor with very high current density (>2400 A/mm/sup 2/ at 5 T) and very small filaments (approx. 2..mu..m in diameter). Previous work has shown that by controlling the formation of Cu/sub 4/Ti compound particles on the filament surfaces it is possible to make fine filamentary NbTi wire with high critical current density. The performance of multi-filamentary wire is characterized by the current density and the quantity ''n'' which describes the superconducting-normal transition. Micrographs of wires having high J/sub c/ and high n show smooth, uniform filaments. Recently wires of very high critical current and high n have been produced in experimental quantities by commercial manufactures.

  10. Experimental study of yttrium barium copper oxide superconducting tape’s critical current under twisting moment

    Indian Academy of Sciences (India)

    Ziauddin Khan; Ananya Kundu; Subrata Pradhan

    2013-10-01

    Critical current (c) characteristics of 2G YBCO superconducting tape under the influence of twisting moment was experimentally investigated at varying current ramp rates in the self-field. Under a uniform twist, the degradation in the current-carrying capacity of YBCO tape up to 30% was observed at 77 K. The degradation is largely attributed to the shear stress and torsional shear strain resulting from the twisting. The superconductor to resistive transition index, , is also found to behave in an identical manner with increase in the twisting. Finite element analysis (FEA) of the tape in the experimental configuration with twisting moment being applied on to it has been carried out in COMSOL. The torsional strain calculated analytically as per the experimental configuration matches closely with that of FEA results, which shows that the critical current degradation is a function of strain.

  11. Nonlocal discrete continuity and invariant currents in locally symmetric effective Schr\\"odinger arrays

    CERN Document Server

    Morfonios, C V; Diakonos, F K; Schmelcher, P

    2016-01-01

    A nonlocal discrete continuity formalism is developed which relates spatial symmetries in subparts of Hermitian or non-Hermitian lattice systems to the properties of adapted nonlocal currents. Broken local symmetries thereby act as current sources or sinks, and the time evolution of the associated nonlocal charge is governed by the nonlocal currents at the boundaries of domains with local symmetry. We apply the framework to locally inversion-(time-) and translation-(time-) symmetric one-dimensional photonic waveguide arrays effectively described by Schr\\"odinger's equation with a tight-binding Hamiltonian. The nonlocal currents of stationary states are shown to be translationally invariant within local symmetry domains for arbitrary wavefunction profiles, and cases of complete, overlapping, and gapped local symmetry are demonstrated for model setups. Two distinct versions of the nonlocal invariant currents enable a mapping between wave amplitudes of symmetry-related sites, thereby generalizing the global Bloc...

  12. Dependence of critical current density on crystalline direction in thin YBCO films

    DEFF Research Database (Denmark)

    Paturi, P.; Peurla, M.; Raittila, J.

    2005-01-01

    The dependence of critical current density (J(c)) on the angle between the current direction and the (100) direction in the ab-plane of thin YBCO films deposited on (001)-SrTiO3 from natiocrystalline and microcrystalline targets is studied using magneto-optical microscopy. In the films made from ...... indicating that in addition to linear defects also the twin boundaries are very important flux pinning sites. (c) 2005 Elsevier B.V. All rights reserved....

  13. Self-organized criticality revisited: non-local transport by turbulent amplification

    DEFF Research Database (Denmark)

    Milovanov, Alexander V.; Rasmussen, Jens Juul

    2015-01-01

    We revise the applications of self-organized criticality (SOC) as a paradigmatic model for tokamak plasma turbulence. The work, presented here, is built around the idea that some systems do not develop a pure critical state associable with SOC, since their dynamical evolution involves as a compet......We revise the applications of self-organized criticality (SOC) as a paradigmatic model for tokamak plasma turbulence. The work, presented here, is built around the idea that some systems do not develop a pure critical state associable with SOC, since their dynamical evolution involves...... with the causes and origins of non-local transport in magnetized plasma, and show that this type of transport occurs naturally in self-consistent strong turbulence via a complexity coupling to the inverse cascade. We expect these coupling phenomena to occur in the parameter range of strong nonlinearity and time...

  14. Critical currents and superconductivity ferromagnetism coexistence in high-Tc oxides

    CERN Document Server

    Khene, Samir

    2016-01-01

    The book comprises six chapters which deal with the critical currents and the ferromagnetism-superconductivity coexistence in high-Tc oxides. It begins by gathering key data for superconducting state and the fundamental properties of the conventional superconductors, followed by a recap of the basic theories of superconductivity. It then discusses the differences introduced by the structural anisotropy on the Ginzburg-Landau approach and the Lawrence-Doniach model before addressing the dynamics of vortices and the ferromagnetism-superconductivity coexistence in high-Tc oxides, and provides an outline of the pinning phenomena of vortices in these materials, in particular the pinning of vortices by the spins. It elucidates the methods to improve the properties of superconducting materials for industrial applications. This optimization aims at obtaining critical temperatures and densities of critical currents at the maximum level possible. Whereas the primary objective is the basic mechanisms pushing the superco...

  15. Critical currents of Rutherford MgB2 cables compacted by two-axial rolling

    Science.gov (United States)

    Kopera, L.; Kováč, P.; Kulich, M.; Melišek, T.; Rindfleisch, M.; Yue, J.; Hušek, I.

    2017-01-01

    Two types of Rutherford cables made of two strand layers of commercial MgB2 wires manufactured by Hyper Tech Research, Inc. have been made. Flat rectangular cables consisting of 12 single-core MgB2/Nb/Cu10Ni, or 6-filaments MgB2/Nb/Cu strands, both of diameter 390 mewm, were assembled using a back-twist cabling machine with transposition length of 20 mm. In order to analyze impact of the cable compaction on critical currents, cables were two-axially rolled, each by a single step reduction of 3.5%-29.7% to thickness range of 0.775-0.62 mm. It was found that by increasing the packing factor (PF) of cable above 0.79, the critical current begins to increase. It is improved nearly two times up to the PF limit 0.89. Compaction over the PF limit introduced cable degradation and decrease of critical current. Bending tests applied to cables showed that critical current degradation starts below the bending diameter 120 mm for 6-filaments Cu sheath and 70 mm for single-core Cu10Ni sheath cable. Tensile tests showed similar irreversible strain values for the both types of cables. Rutherford cables assembled of single-core strands are promising for low field (2.7-4 T) applications where low bending diameters are required.

  16. Measurement of critical current of superconducting materials at the changing magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Qingrong; Hu Yongchang

    1986-06-01

    In this paper we present a new method for measuring the critical current of superconductor materials. The experimental results indicate the I/sub c/(H) character of the samples rather directly and, comparing with other methods, we can get more data at the same interval.

  17. Critical current density in wire drawn and hydrostatically extruded Nb-Ti superconductors

    Science.gov (United States)

    Alterovitz, S. A.; Woollam, J. A.; Collings, E. W.

    1979-01-01

    Critical current studies have been made on copper-clad Nb-Ti composite wire prepared under area reductions of 100:1 and 10,000:1 by hydrostatic extrusion (HE), wire drawing and HE plus drawing. Comparative evaluation of the thermomechanical processing equivalent of HE was performed.

  18. Investigation of the Critical Current Density of YBaCuO high-temperature Superconductor Ceramic

    OpenAIRE

    METSKHVARISHVILI, I. R.; KEKELIDZE, N. P.; METSKHVARISHVILI, M. R.

    2002-01-01

    The method of high harmonics is used to investigate penetration of low magnetic fields within the Y1Ba2Cu3O7 high-temperature superconductor ceramic. Given experimental results are explained by the modal dependencies between the value of critical current density and the magnetic induction B: jc(B) = jc(0){\\frac{{B02}} {{B02 + B2}}}.

  19. AFM nano-plough planar YBCO micro-bridges: critical currents and magnetic field effects.

    Science.gov (United States)

    Elkaseh, A A O; Perold, W J; Srinivasu, V V

    2010-10-01

    The critical current (Ic) of YBa2Cu3O7-x (YBCO) AFM plough micro-constrictions is measured as a function of temperature, width and the magnetic flux density (B), which was applied perpendicular to the YBCO ab-plane and surface of the bridges. C-axis oriented thin films of YBa2Cu3O7-x were deposited on MgO substrates using an inverted cylindrical magnetron (ICM) sputtering technique. The films were then patterned into 8-10 micron size strips, using standard photolithography and dry etching processes. Micro-bridges with widths between 1.9 microm to 4.1 microm were fabricated by using atomic force microscope (AFM) nanolithography techniques. Critical current versus temperature data shows a straight-line behavior, which is typical of constriction type Josephson junctions. The Ic versus B characteristics exhibited a modulation, and a suppression of the critical current of up to 84%. It was also found that the critical current increases with increasing constriction width.

  20. Critical Infrastructure Vulnerability to Spatially Localized Failures with Applications to Chinese Railway System.

    Science.gov (United States)

    Ouyang, Min; Tian, Hui; Wang, Zhenghua; Hong, Liu; Mao, Zijun

    2017-01-17

    This article studies a general type of initiating events in critical infrastructures, called spatially localized failures (SLFs), which are defined as the failure of a set of infrastructure components distributed in a spatially localized area due to damage sustained, while other components outside the area do not directly fail. These failures can be regarded as a special type of intentional attack, such as bomb or explosive assault, or a generalized modeling of the impact of localized natural hazards on large-scale systems. This article introduces three SLFs models: node centered SLFs, district-based SLFs, and circle-shaped SLFs, and proposes a SLFs-induced vulnerability analysis method from three aspects: identification of critical locations, comparisons of infrastructure vulnerability to random failures, topologically localized failures and SLFs, and quantification of infrastructure information value. The proposed SLFs-induced vulnerability analysis method is finally applied to the Chinese railway system and can be also easily adapted to analyze other critical infrastructures for valuable protection suggestions.

  1. The critical current irreversibility of Bi(2223)/Ag tape and its modification

    Institute of Scientific and Technical Information of China (English)

    兰玉成; 郭树权; 肖业皋; 叶斌; 曾荣; 周怡茹

    1996-01-01

    The critical currents of Bi(2223)/Ag tape at magnetic fields up to 2.5T have been measured at different field orientations. The IC values depend on the history of magnetic fields. This phenomenon can be explained in terms of irreversibility of the effective magnetic field caused by the induced persistent current and the screening persistent current. If the mean of the increasing and the decreasing applied field (Hap), defined as the effective field (Hcff), is linearly related to the applied field, i.e. Heff, using Heff instead of Hap, the modified IC(H) curves curves are obtainable.

  2. Direct mapping of local redox current density on a monolith electrode by laser scanning.

    Science.gov (United States)

    Lee, Seung-Woo; Lopez, Jeffrey; Saraf, Ravi F

    2013-09-15

    An optical method of mapping local redox reaction over a monolith electrode using simple laser scanning is described. As the optical signal is linearly proportional to the maximum redox current that is measured concomitantly by voltammetry, the optical signal quantitatively maps the local redox current density distribution. The method is demonstrated on two types of reactions: (1) a reversible reaction where the redox moieties are ionic, and (2) an irreversible reaction on two different types of enzymes immobilized on the electrode where the reaction moieties are nonionic. To demonstrate the scanning capability, the local redox behavior on a "V-shaped" electrode is studied where the local length scale and, hence, the local current density, is nonuniform. The ability to measure the current density distribution by this method will pave the way for multianalyte analysis on a monolith electrode using a standard three-electrode configuration. The method is called Scanning Electrometer for Electrical Double-layer (SEED).

  3. Critical depinning current of elastic vortex strings in superconductors with extended linear defects

    Science.gov (United States)

    Fedirko, V. A.; Kasatkin, A. L.; Polyakov, S. V.

    2016-09-01

    The problem of the depinning of an Abrikosov elastic vortex string from an extended linear defect in the plate of a 3 D anisotropic superconductor of thickness d > 2λ (where λ is the London penetration depth) under the action of an inhomogeneously distributed transport current that flows in the surface shielding layer has been solved using classical mechanics approach. Conditions for the appearance of the instability of the pinned state of a vortex have been investigated and calculations of the corresponding critical current density on the surface at which the depinning of the vortex string occurs have been carried out. The dependence of the average of the critical current density on the thickness of the plate has been determined.

  4. Localized persistent spin currents in defect-free quasiperiodic rings with Aharonov–Casher effect

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, R.Z.; Chen, C.H.; Cheng, Y.H.; Hsueh, W.J., E-mail: hsuehwj@ntu.edu.tw

    2015-06-26

    We propose strongly localized persistent spin current in one-dimensional defect-free quasiperiodic Thue–Morse rings with Aharonov–Casher effect. The results show that the characteristics of these localized persistent currents depend not only on the radius filling factor, but also on the strength of the spin–orbit interaction. The maximum persistent spin currents in systems always appear in the ring near the middle position of the system array whether or not the Thue–Morse rings array is symmetrical. The magnitude of the persistent currents is proportional to the sharpness of the resonance peak, which is dependent on the bandwidth of the allowed band in the band structure. The maximum persistent spin currents also increase exponentially as the generation order of the system increases. - Highlights: • Strongly localized persistent spin current in quasiperiodic AC rings is proposed. • Localized persistent spin currents are much larger than those produced by traditional mesoscopic rings. • Characteristics of the localized persistent currents depend on the radius filling factor and SOI strength. • The maximum persistent current increases exponentially with the system order. • The magnitude of the persistent currents is related to the sharpness of the resonance.

  5. Effects of rf current on critical field for magnetization reversal in spin torque devices

    Science.gov (United States)

    Chen, Wenyu; Florez, Sylvia; Katine, Jordan; Carey, Matthew; Folks, Liesl; Terris, Bruce

    2009-03-01

    Current induced switching assisted by rf current has recently been observed in spin torque devices at low temperature [1, 2]. This effect allows control of spin transfer induced magnetization reversal through the frequency of an injected rf current. In this study, the effects of the rf current injection on critical field for magnetization reversal in spin valve junctions have been investigated. Measurements were conducted at room temperature, and the magnetic field was applied along the easy axis of the junction. An rf current was injected into the nanojunction at various frequencies ranging between 1 and 20 GHz. The dynamic resistance, dV/dI, was measured as a function of the rf frequency, power and the dc bias current while ramping the magnetic field. The rf current injection was observed to change the critical field for free layer magnetization reversal when the intrinsic spin-transfer-induced dynamics is frequency-locked with the injected rf. The results will be discussed in the context of macrospin models of spin transfer in metallic spin valve structures. [1] S. H. Florez et al. Phys. Rev. B 78, 184403 (2008) [2] Y.-T. Cui et al. Phys. Rev. B 77, 214440 (2008)

  6. High critical current of Ti-sheathed MgB{sub 2} wires for AC and weight-critical applications

    Energy Technology Data Exchange (ETDEWEB)

    Alessandrini, M; Fang, H; Hanna, M; Putman, P; Zhou, Y X; Salama, K [Department of Mechanical Engineering and Texas Center for Superconductivity, University of Houston, Houston, TX 77204-4006 (United States)

    2006-01-15

    The peculiar features of magnesium diboride make it suitable for many potential applications. In the last four years of investigation of MgB{sub 2}, the scientific community's research was mainly motivated by features such as low cost, compatibility with straightforward processing methods, relatively high critical temperature, and absence of weak links between grains. Other applications suggest the accentuation of other MgB{sub 2} properties. In particular its very low mass density makes it attractive for space activities, where the cost per kilogram for orbiting is still a huge obstacle, e.g. the cost of transport to low Earth orbit can reach 15 k$ kg{sup -1}. In order to promote the use of this compound for space activities, we tested titanium as a sheath material. Titanium is non-magnetic and its alloys are almost half the weight of steel but with yield stresses up to three times higher. We fabricated Ti-sheathed MgB{sub 2} through the powder-in-tube process. These wires show similar results to those sheathed with Fe. At 4 K the critical current density J{sub c} is well above 7 x 10{sup 5} A cm{sup -2}. The interface between the superconducting intermetallic compound and the lightweight sheath does not show any evidence of reaction and diffusion up to 900 deg. C. An analysis was carried out using x-ray diffraction, scanning electron microscopy with an energy dispersive spectrometer, and electron microprobe analysis.

  7. Comparison between the magnetic and transport critical current densities in high critical current density melt-textured yttrium barium copper-oxide

    Science.gov (United States)

    Gao, L.; Meng, R. L.; Xue, Y. Y.; Hor, P. H.; Chu, C. W.

    1991-01-01

    Using a recently developed pulsed critical current density (Jc) measuring system, the Jc of the high-Jc melt-textured YBa2Cu3O(7-delta) (Y123) bulk samples has been determined. I-V curves with a voltage resolution of 0.5 microV were obtained, and transport Jc's along the a-b plane as high as 7.2 x 10 to the 4th A/sq cm were extracted. These results are comparable to the values obtained magnetically. On the other hand, transport Jc along the c axis were found to be two orders of magnitude smaller, even though the magnetic Jc along the c axis is only about five times smaller than Jc along the a-b plane. It is suggested that for the high-temperature superconducting materials which are highly anisotropic, caution should be taken when using the nontransport magnetic methods to determine Jc.

  8. CRITICAL CURRENT AND JUNCTION BETWEEN PANCAKE STUDIES FOR HTS COIL DESIGN

    CERN Document Server

    Lécrevisse, Y; Louchart, O; Rey, J-M; Tixador, P

    2011-01-01

    YBCO Coated Conductor (CC) are very attractive for very high magnetic field coil with lower cryogenics need. We study two major aspects of HTS coil building. First the results of critical current measurements on YBCO tape provided by SuperPower are presented for a large temperature range and in parallel magnetic field configuration. A model is also proposed to extrapolate those measurements at other temperatures and fields. Then we focus on the critical aspect of junctions between pancakes. Junctions in cylindrical configuration are studied using three different soldering materials. The results are promising for further coil building.

  9. Risk prediction of Critical Infrastructures against extreme natural hazards: local and regional scale analysis

    Science.gov (United States)

    Rosato, Vittorio; Hounjet, Micheline; Burzel, Andreas; Di Pietro, Antonio; Tofani, Alberto; Pollino, Maurizio; Giovinazzi, Sonia

    2016-04-01

    Natural hazard events can induce severe impacts on the built environment; they can hit wide and densely populated areas, where there is a large number of (inter)dependent technological systems whose damages could cause the failure or malfunctioning of further different services, spreading the impacts on wider geographical areas. The EU project CIPRNet (Critical Infrastructures Preparedness and Resilience Research Network) is realizing an unprecedented Decision Support System (DSS) which enables to operationally perform risk prediction on Critical Infrastructures (CI) by predicting the occurrence of natural events (from long term weather to short nowcast predictions, correlating intrinsic vulnerabilities of CI elements with the different events' manifestation strengths, and analysing the resulting Damage Scenario. The Damage Scenario is then transformed into an Impact Scenario, where punctual CI element damages are transformed into micro (local area) or meso (regional) scale Services Outages. At the smaller scale, the DSS simulates detailed city models (where CI dependencies are explicitly accounted for) that are of important input for crisis management organizations whereas, at the regional scale by using approximate System-of-Systems model describing systemic interactions, the focus is on raising awareness. The DSS has allowed to develop a novel simulation framework for predicting earthquakes shake maps originating from a given seismic event, considering the shock wave propagation in inhomogeneous media and the subsequent produced damages by estimating building vulnerabilities on the basis of a phenomenological model [1, 2]. Moreover, in presence of areas containing river basins, when abundant precipitations are expected, the DSS solves the hydrodynamic 1D/2D models of the river basins for predicting the flux runoff and the corresponding flood dynamics. This calculation allows the estimation of the Damage Scenario and triggers the evaluation of the Impact Scenario

  10. Critical Phenomenon in a Neural Network Model: A Localization-Delocalization Transition of Excited Clusters

    Science.gov (United States)

    Satoh, Kazuhiro; Okabe, Yutaka

    1993-01-01

    Numerical study is done on a critical phenomenon in a neural network model of the McCulloch-Pitts type. Such a net, one of excitable media, consists of “neurons” (binary decision elements) each of which randomly sits on a square lattice and is connected to its four neighbors. When the net is activated locally, the “fire” spreads over from the origin according to the deterministic rule. After transient, a self-sustained mode of excitation (time-periodic firing pattern) is established. It is found that a size of the largest excitation tends to diverge as the excitability of the net is increased (a localization-delocalization transition). Numerically evaluated power-law exponents suggest that the criticality of such transition belongs to the same universality class of the percolation transition.

  11. Local criticality, diffusion and chaos in generalized Sachdev-Ye-Kitaev models

    CERN Document Server

    Gu, Yingfei; Stanford, Douglas

    2016-01-01

    The Sachdev-Ye-Kitaev model is a $(0+1)$-dimensional model describing Majorana fermions or complex fermions with random interactions. This model has various interesting properties such as approximate local criticality (power law correlation in time), zero temperature entropy, and quantum chaos. In this article, we propose a higher dimensional generalization of the Sachdev-Ye-Kitaev model, which is a lattice model with $N$ Majorana fermions at each site and random interactions between them. Our model can be defined on arbitrary lattices in arbitrary spatial dimensions. In the large $N$ limit, the higher dimensional model preserves many properties of the Sachdev-Ye-Kitaev model such as local criticality in two-point functions, zero temperature entropy and chaos measured by the out-of-time-ordered correlation functions. In addition, we obtain new properties unique to higher dimensions such as diffusive energy transport and a "butterfly velocity" describing the propagation of chaos in space. We mainly present res...

  12. Localization transition in random Lévy matrices: multifractality of eigenvectors in the localized phase and at criticality

    Science.gov (United States)

    Monthus, Cécile

    2016-09-01

    For random Lévy matrices of size N× N , where matrix elements are drawn with some heavy-tailed distribution P≤ft({{H}ij}\\right)\\propto {{N} -1}|{{H}ij}{{|}-1-μ} with 0text{max}}∼ {{N}\\frac{1μ}} . Here we study the localization properties of the corresponding eigenvectors via some strong disorder perturbative expansion that remains consistent within the localized phase and that yields their inverse participation ratios (IPR) Y q as a function of the continuous parameter 0. In the region 0  q c but diverge in the region 0  text{c}}=1 corresponding to Cauchy matrices: the IPR Y q of the corresponding critical eigenstates follow the strong-multifractality spectrum characterized by the generalized fractal dimensions {{D}\\text{criti}}(q)=\\frac{1-2q}{1-q}θ ≤ft(0≤slant q≤slant \\frac{1}{2}\\right) , which has been found previously in various other Localization problems in spaces of effective infinite dimensionality.

  13. On localization with robust power control for safety critical wireless sensor networks

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A hybrid methodology is proposed for use in low power, safety critical wireless sensor network applications, where quality-of-service orientated transceiver output power control is required to operate in parallel with radio frequency-based localization. The practical implementation is framed in an experimental procedure designed to track a moving agent in a realistic indoor environment. An adaptive time synchronized approach is employed to ensure the positioning technique can operate effectively in the pres...

  14. Quantum Hall criticality and localization in graphene with short-range impurities at the Dirac point.

    Science.gov (United States)

    Gattenlöhner, S; Hannes, W-R; Ostrovsky, P M; Gornyi, I V; Mirlin, A D; Titov, M

    2014-01-17

    We explore the longitudinal conductivity of graphene at the Dirac point in a strong magnetic field with two types of short-range scatterers: adatoms that mix the valleys and "scalar" impurities that do not mix them. A scattering theory for the Dirac equation is employed to express the conductance of a graphene sample as a function of impurity coordinates; an averaging over impurity positions is then performed numerically. The conductivity σ is equal to the ballistic value 4e2/πh for each disorder realization, provided the number of flux quanta considerably exceeds the number of impurities. For weaker fields, the conductivity in the presence of scalar impurities scales to the quantum-Hall critical point with σ≃4×0.4e2/h at half filling or to zero away from half filling due to the onset of Anderson localization. For adatoms, the localization behavior is also obtained at half filling due to splitting of the critical energy by intervalley scattering. Our results reveal a complex scaling flow governed by fixed points of different symmetry classes: remarkably, all key manifestations of Anderson localization and criticality in two dimensions are observed numerically in a single setup.

  15. Critical properties of the Anderson localization transition and the high-dimensional limit

    Science.gov (United States)

    Tarquini, E.; Biroli, G.; Tarzia, M.

    2017-03-01

    In this paper we present a thorough study of transport, spectral, and wave-function properties at the Anderson localization critical point in spatial dimensions d =3 , 4, 5, 6. Our aim is to analyze the dimensional dependence and to assess the role of the d →∞ limit provided by Bethe lattices and treelike structures. Our results strongly suggest that the upper critical dimension of Anderson localization is infinite. Furthermore, we find that dU=∞ is a much better starting point compared to dL=2 to describe even three-dimensional systems. We find that critical properties and finite-size scaling behavior approach by increasing d those found for Bethe lattices: the critical state becomes an insulator characterized by Poisson statistics and corrections to the thermodynamics limit become logarithmic in the number N of lattice sites. In the conclusion, we present physical consequences of our results, propose connections with the nonergodic delocalized phase suggested for the Anderson model on infinite-dimensional lattices, and discuss perspectives for future research studies.

  16. Evidence for enhancement of critical current by intergrain Ag in YBaCuO-Ag ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Dwir, B.; Affronte, M.; Pavuna, D.

    1989-07-24

    We report the evidence for enhancement of critical current density /ital J//sub /ital c// by /similar to/50%, which occurs when /similar to/10 wt. % Ag is added to Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7/minus//delta// ceramics. The maximal /ital J//sub /ital c// (/similar to/700 A/cm/sup 2/ at /ital T/=77 K) appears simultaneously with maximum YBaCuO compactness in the samples. The silver fills the intergranular space (holes) without Cu substitution, and the critical temperature /ital T//sub /ital c// is not reduced from the bulk value (/similar to/91 K). Normal-state resistivity of Ag-YBaCuO samples is decreased by an order of magnitude, and samples exhibit improved contact resistance and resistance to water. While the critical density is improved by adding /similar to/10 wt. % Ag, it decreases at higher Ag concentrations.

  17. Range-based underwater vehicle localization in the presence of unknown ocean currents: Theory and experiments

    Digital Repository Service at National Institute of Oceanography (India)

    Bayat, M.; Crasta, N.; Aguiar, A.P.; Pascoal, A.M.

    This paper addresses the problem of range-based autonomous underwater vehicle (AUV) localization in the presence of unknown ocean currents. In the setup adopted, the AUV is equipped with an attitude and heading reference system, a depth sensor...

  18. Strong critical current density enhancement in NiCu/NbN superconducting nanostripes for optical detection

    Science.gov (United States)

    Marrocco, N.; Pepe, G. P.; Capretti, A.; Parlato, L.; Pagliarulo, V.; Peluso, G.; Barone, A.; Cristiano, R.; Ejrnaes, M.; Casaburi, A.; Kashiwazaki, N.; Taino, T.; Myoren, H.; Sobolewski, Roman

    2010-08-01

    We present measurements of ferromagnet/superconductor (NiCu/NbN) and plain superconducting (NbN) nanostripes with the linewidth ranging from 150 to 300 nm. The NiCu (3 nm)/NbN (8 nm) bilayers, as compared to NbN (8 nm), showed a up to six times increase in their critical current density, reaching at 4.2 K the values of 5.5 MA/cm2 for a 150 nm wide nanostripe meander and 12.1 MA/cm2 for a 300 nm one. We also observed six-time sensitivity enhancement when the 150 nm wide NiCu/NbN nanostripe was used as an optical detector. The strong critical current enhancement is explained by the vortex pinning strength and density increase in NiCu/NbN bilayers and confirmed by approximately tenfold increase in the vortex polarizability factor.

  19. Critical report of current fisheries management measures implemented for the North Sea mixed demersal fisheries

    DEFF Research Database (Denmark)

    Nielsen, J. Rasmus; Ulrich, Clara; Hegland, Troels J.

    The present report is an EU-FP7-SOCIOEC Report giving an overview and critical evaluation of the current management measures implemented for the North Sea mixed demersal fisheries and the fish stocks involved in this. Also, this involves review and critical evaluation of the scientific advice sup...... to distinguish specific effects and impacts of each individual measures implemented. Accordingly, it is also very difficult to make scientific management evaluation and advice associated to the individual measures......The present report is an EU-FP7-SOCIOEC Report giving an overview and critical evaluation of the current management measures implemented for the North Sea mixed demersal fisheries and the fish stocks involved in this. Also, this involves review and critical evaluation of the scientific advice....... The prevailing management system and principle has been landing quotas (TAC, Total Allowable Catch) mainly based on the EU principle of relative stability in the international sharing of the TAC. Also, general effort limitations and technical measures are set for the EU and Norwegian fisheries on top of the TAC...

  20. Analysis of the ac SQUID with low inductance and low critical current

    DEFF Research Database (Denmark)

    Sørensen, O. H.

    1976-01-01

    The properties of the ac SQUID magnetometer has been analyzed. The results are valid in the low-inductance low-critical-current regime, where the Lri0 producted is belowthe value at which the relation between the enclosed and externally applied magnetic dc flux becomes reentrant. The effects...... of the screening current circulating in the SQUID ring as well as of the SQUID-ring time constant, tau-Lr/R9 are taken into account. Here LR IS THE SQUID-ring inductance, and R is the shunt resistance in the shunted junction model assumed to describe the weak link. It is shown that for finite values of omegatau...

  1. Altering critical depinning current via domain wall pile-up in magnetic nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Liwei D.; Jin, Yongmei M., E-mail: ymjin@mtu.edu

    2015-11-01

    An important role of domain wall pile-up in current-driven domain wall depinning in magnetic nanowires is revealed using micromagnetic simulations. It is found that the critical current for domain wall depinning can be substantially reduced and conveniently tuned by controlling domain wall number in the pile-up at pinning site, in analogy to dislocation pile-up responsible for Hall–Petch effect in mechanical strength. Domain wall pinning and depinning at an s-shape bend is considered, and the effects of curvature and current crowding in magnetic circuit on domain wall behaviors are discussed. - Highlights: • Advance fundamental knowledge of current-driven domain wall phenomena. • Provide a novel approach to drastically reduce the critical depinning current. • Solve an outstanding problem of effective control of domain wall pinning/depinning. • Report appealing new findings of magnetic domain wall pile-up mechanism. • Overcome the limitations of materials properties for domain wall-based devices.

  2. On the study of phase formation and critical current density in superconducting MgB2

    Indian Academy of Sciences (India)

    Suchitra Rajput; Sujeet Chaudhary; Subhash C Kashyap; Pankaj Srivastava

    2006-06-01

    Superconducting bulk MgB2 samples have been synthesized by employing sintering technique without using any additional process steps, generally undertaken in view of the substantial loss of magnesium, during heat treatment. Starting with Mg rich powders having different atomic ratios of Mg : B, as against the nominally required Mg : B = 1 : 2 ratio, we have obtained superconducting MgB2 samples of different characteristics. The effect of excess Mg in the starting mixture and processing temperature on the phase-formation, transition temperature (C) and critical current density (C) have been investigated by electrical transport and a.c. susceptibility measurements. The X-ray diffraction and X-ray photoelectron spectroscopic analyses of MgB2 bulk samples have been carried out to understand the role of excess Mg and the effect of processing temperature. It is established that MgB2 samples with high critical current density can be synthesized from a Mg rich powder having Mg : B in 2 : 2 ratio, at temperatures around 790°C. Critical current density has been found to vary systematically with processing temperature.

  3. Josephson critical current of long SNS junctions in the presence of a magnetic field

    Science.gov (United States)

    Meier, Hendrik; Fal'Ko, Vladimir I.; Glazman, Leonid I.

    We evaluate the Josephson critical current of a long and wide two-dimensional superconductor-normal metal-superconductor (SNS) junction, taking into account the effect of electron reflection off the side edges of the junction. Considering clean junctions, we find that the effect of edges alters the usual Fraunhofer-like dependence of the Josephson critical current Ic on the magnetic flux Φ. At relatively weak fields, B edge effect lifts zeros of the Ic (Φ) dependence and gradually shifts the maxima of that function by Φ0 / 2 . (Here W is the width of the junction and Φ0 the magnetic flux quantum.) At higher fields, B >~Φ0 /W2 , the edge effect leads to an accelerated decay of the critical current Ic (Φ) with increasing Φ. Our results are robust with respect to the roughness of realistic boundaries. Finally, we discuss the role of mesoscopic fluctuations of Ic (Φ) originating from the scattering off the edges, and compare our findings to recent experiments.

  4. Intracardiac Origin of Heart Rate Variability, Pacemaker Funny Current and their Possible Association with Critical Illness

    Science.gov (United States)

    Papaioannou, Vasilios E; Verkerk, Arie O; Amin, Ahmed S; de Bakker, Jaques MT

    2013-01-01

    Heart rate variability (HRV) is an indirect estimator of autonomic modulation of heart rate and is considered a risk marker in critical illness, particularly in heart failure and severe sepsis. A reduced HRV has been found in critically ill patients and has been associated with neuro-autonomic uncoupling or decreased baroreflex sensitivity. However, results from human and animal experimental studies indicate that intracardiac mechanisms might also be responsible for interbeat fluctuations. These studies have demonstrated that different membrane channel proteins and especially the so-called ‘funny’ current (If), an hyperpolarization-activated, inward current that drives diastolic depolarization resulting in spontaneous activity in cardiac pacemaker cells, are altered during critical illness. Furthermore, membrane channels kinetics seem to have significant impact upon HRV, whose early decrease might reflect a cellular metabolic stress. In this review article we present research findings regarding intracardiac origin of HRV, at the cellular level and in both isolated sinoatrial node and whole ex vivo heart preparations. In addition, we will review results from various experimental studies that support the interrelation between If and HRV during endotoxemia. We suggest that reduced HRV during sepsis could also be associated with altered pacemaker cell membrane properties, due to ionic current remodeling. PMID:22920474

  5. Effect of a pinning field on the critical current density for current-induced domain wall motion in perpendicular magnetic anisotropy nanowires.

    Science.gov (United States)

    Ooba, Ayaka; Fujimura, Yuma; Takahashi, Kota; Komine, Takashi; Sugita, Ryuji

    2012-09-01

    In this study, the effect of a pinning field on the critical current density for current-induced domain wall motion in nanowires with perpendicular magnetic anisotropy was investigated using micromagnetic simulations. In order to estimate the pinning field in notched nanowires, we conducted wall energy calculations for nanowires with various saturation magnetizations. The pinning field increased as the notch size increased. The pinning field decreased as the saturation magnetization decreased. As a result, the decreased in the pinning field causes the reduction of the critical current density. Therefore, a significant reduction of the critical current density can be obtained by decreasing the saturation magnetization, even if wall pinning occurs.

  6. The local property taxes and municipal federalism. Current and future inequity condition of Italian Property Taxation

    Directory of Open Access Journals (Sweden)

    Michele Argiolas

    2013-08-01

    Full Text Available The main purpose of this paper is to analyze and compare the current local tax on real estate and the future and assessing criticality. The tax base is calculated by applying calculation methods that differ depending on the type of property you must tax. For buildings used for residential, the tax base is calculated on the basis of the cadastral income; in the case of building land is rather used the market value of land and buildings and, for rent, rural manor. The land property values are always lower than market values, which is because some time trying to implement a revision of the class with the objective of bringing the two values. The reclass procedure has recently been adopted in the municipality of Milano where it was decided to reclass of buildings located within a few micro-climates for the most central, in which houses were originally built affordable housing to meet the housing needs of the social classes poor and that over time turned into mansions in the city center. From 1 January 2012, the Imu will come into force, only municipal tax, which replaces the current Ici; the two taxes differ in the higher fixed rate (7.6 ‰, which does not involve substantial modifications to the old system tax. In this way, the result will be to produce an increase in the tax burden without solving the inequalities of the old system but increasing the gap. The Implementation Act contains provisions which IMU when applied to allow municipalities to solve some problems present in the Ici.

  7. Ship waves on uniform shear current at finite depth: wave resistance and critical velocity

    CERN Document Server

    Li, Yan

    2016-01-01

    We present a comprehensive theory for linear gravity-driven ship waves in the presence of a shear current with uniform vorticity, including the effects of finite water depth. The wave resistance in the presence of shear current is calculated for the first time, containing in general a non-zero lateral component. While formally apparently a straightforward extension of existing deep water theory, the introduction of finite water depth is physically non-trivial, since the surface waves are now affected by a subtle interplay of the effects of the current and the sea bed. This becomes particularly pronounced when considering the phenomenon of critical velocity, the velocity at which transversely propagating waves become unable to keep up with the moving source. The phenomenon is well known for shallow water, and was recently shown to exist also in deep water in the presence of a shear current [Ellingsen, J.~Fluid Mech.\\ {\\bf 742} R2 (2014)]. We derive the exact criterion for criticality as a function of an intrin...

  8. The influence of critical current density of Bi-2212 superconductors by defects after Yb-doping

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Tianni [State key Laboratory for Mechanical Behavior of Materials of Xi' an Jiaotong University, Xi' an 710014 (China); SMRC, Northwest Institute for Nonferrous Metal Research, Xi' an 710016 (China); Zhang, Cuiping [SMRC, Northwest Institute for Nonferrous Metal Research, Xi' an 710016 (China); Guo, Shengwu [State key Laboratory for Mechanical Behavior of Materials of Xi' an Jiaotong University, Xi' an 710014 (China); Wu, Yifang [State key Laboratory for Mechanical Behavior of Materials of Xi' an Jiaotong University, Xi' an 710014 (China); SMRC, Northwest Institute for Nonferrous Metal Research, Xi' an 710016 (China); Li, Chengshan, E-mail: csli368@126.com [SMRC, Northwest Institute for Nonferrous Metal Research, Xi' an 710016 (China); Zhou, Lian [State key Laboratory for Mechanical Behavior of Materials of Xi' an Jiaotong University, Xi' an 710014 (China); SMRC, Northwest Institute for Nonferrous Metal Research, Xi' an 710016 (China)

    2015-12-15

    Highlights: • Ca substituting Yb element in Bi-2212 single crystal. • The critical current density of this sample is the highest without the optimal Tc value. • The Cu–O{sub 2} and Ca–O layers in pure and doping samples are observed using HRTEM. • The optimal defect density is calculated. - Abstract: Bi{sub 2}Sr{sub 2}Ca{sub 1−x}Yb{sub x}Cu{sub 2}O{sub 8+δ} (Bi-2212) single crystals with x = 0.000, 0.005, 0.010 and 0.020 have been prepared by self-flux method. The influences of Yb doping on the formation of the dislocations in the lattice structures, as well as the related current carrying capability are investigated. Due to the SQUID measurement and the Bean model calculation, the maximum critical current density (Jc) is obtained when the Yb doping content is x = 0.010, though the Tc and the carrier concentration are not in the optimal region. Based on the HRTEM analyses of the Ca–O and Cu–O{sub 2} layers, the optimal dislocation density in the Cu–O{sub 2} layers is deduced according to the number of the dislocations per unit area. Besides, the sizes of the dislocations also prove the effectiveness of Yb substitution on the enhancement of the current carrying capability in Bi-2212 single crystals.

  9. Can critical inquiry differ from criticism? A dialogue with current occupational science and occupational therapy schools of inquiry

    Directory of Open Access Journals (Sweden)

    Jessie Wilson

    2016-07-01

    Full Text Available Introduction: Critical inquiry has been adopted by various academic disciplines. However, there is a lack of consistency and transparency in the way this complex theoretical and methodological position is applied in research. For novice researchers that ambiguity can lead to blurring the conceptual distinction between critical research and the act of criticizing. Objective: The purpose of this essay is to reflect on what it means to keep a critical perspective for novice researchers. Method: The concepts are explored through a personal narrative that allows authors to examine the details of their trajectory to embrace a critical perspective, which has the power to lead to change, both personal and social. Results: We explore the methodological foundations of the critical research and observe how the emotion is taken over or suppressed in the investigation process. Conclusion: We contextualize key concepts of critical investigation, examining its recent application both in occupational science and in occupational therapy.

  10. Definition of current density in the presence of a non-local potential.

    Science.gov (United States)

    Li, Changsheng; Wan, Langhui; Wei, Yadong; Wang, Jian

    2008-04-16

    In the presence of a non-local potential arising from electron-electron interaction, the conventional definition of current density J(c) = (e/2m)([(p-eA)ψ](*)ψ-ψ(*)[(p-eA)ψ]) cannot satisfy the condition of current conservation, i.e., [Formula: see text] in the steady state. In order to solve this problem, we give a new definition of current density including the contribution due to the non-local potential. We show that the current calculated based on the new definition of current density conserves the current and is the same as that obtained from the Landauer-Büttiker formula. Examples are given to demonstrate our results.

  11. Recalled peer relationship experiences and current levels of self-criticism and self-reassurance.

    Science.gov (United States)

    Kopala-Sibley, Daniel C; Zuroff, David C; Leybman, Michelle J; Hope, Nora

    2013-03-01

    Numerous studies have shown that personality factors may increase or decrease individuals' vulnerability to depression, but little research has examined the role of peer relationships in the development of these factors. Accordingly, this study examined the role of recalled parenting and peer experiences in the development of self-criticism and self-reassurance. It was hypothesized that, controlling for recalled parenting behaviours, specific recalled experiences of peer relationships would be related to current levels of specific forms of self-criticism and self-reassurance. Hypotheses were tested using a retrospective design in which participants were asked to recall experiences of parenting and peer relationships during early adolescence. This age was chosen as early adolescence has been shown to be a critical time for the development of vulnerability to depression. A total of 103 female and 97 male young adults completed measures of recalled parenting, overt and relational victimization and prosocial behaviour by peers, and current levels of self-criticism and self-reassurance. Hierarchical regression analyses showed that parents and peers independently contributed to the development of self-criticism and self-reassurance. Specifically, controlling for parental care and control, overt victimization predicted self-hating self-criticism, relational victimization predicted inadequacy self-criticism, and prosocial behaviour predicted self-reassurance. As well, prosocial behaviour buffered the effect of overt victimization on self-reassurance. Findings highlight the importance of peers in the development of personality risk and resiliency factors for depression, and suggest avenues for interventions to prevent the development of depressive vulnerabilities in youth. The nature of a patient's personality vulnerability to depression may be better understood through a consideration of the patient's relationships with their peers as well as with parents during

  12. High critical currents in iron-clad superconducting MgB2 wires.

    Science.gov (United States)

    Jin, S; Mavoori, H; Bower, C; van Dover, R B

    2001-05-31

    Technically useful bulk superconductors must have high transport critical current densities, Jc, at operating temperatures. They also require a normal metal cladding to provide parallel electrical conduction, thermal stabilization, and mechanical protection of the generally brittle superconductor cores. The recent discovery of superconductivity at 39 K in magnesium diboride (MgB2) presents a new possibility for significant bulk applications, but many critical issues relevant for practical wires remain unresolved. In particular, MgB2 is mechanically hard and brittle and therefore not amenable to drawing into the desired fine-wire geometry. Even the synthesis of moderately dense, bulk MgB2 attaining 39 K superconductivity is a challenge because of the volatility and reactivity of magnesium. Here we report the successful fabrication of dense, metal-clad superconducting MgB2 wires, and demonstrate a transport Jc in excess of 85,000 A cm-2 at 4.2 K. Our iron-clad fabrication technique takes place at ambient pressure, yet produces dense MgB2 with little loss of stoichiometry. While searching for a suitable cladding material, we found that other materials dramatically reduced the critical current, showing that although MgB2 itself does not show the 'weak-link' effect characteristic of the high-Tc superconductors, contamination does result in weak-link-like behaviour.

  13. High critical currents in iron-clad superconducting MgB2 wires

    Science.gov (United States)

    Jin, S.; Mavoori, H.; Bower, C.; van Dover, R. B.

    2001-05-01

    Technically useful bulk superconductors must have high transport critical current densities, Jc, at operating temperatures. They also require a normal metal cladding to provide parallel electrical conduction, thermal stabilization, and mechanical protection of the generally brittle superconductor cores. The recent discovery of superconductivity at 39K in magnesium diboride (MgB2) presents a new possibility for significant bulk applications, but many critical issues relevant for practical wires remain unresolved. In particular, MgB2 is mechanically hard and brittle and therefore not amenable to drawing into the desired fine-wire geometry. Even the synthesis of moderately dense, bulk MgB2 attaining 39K superconductivity is a challenge because of the volatility and reactivity of magnesium. Here we report the successful fabrication of dense, metal-clad superconducting MgB2 wires, and demonstrate a transport Jc in excess of 85,000Acm-2 at 4.2K. Our iron-clad fabrication technique takes place at ambient pressure, yet produces dense MgB2 with little loss of stoichiometry. While searching for a suitable cladding material, we found that other materials dramatically reduced the critical current, showing that although MgB2 itself does not show the `weak-link' effect characteristic of the high-Tc superconductors, contamination does result in weak-link-like behaviour.

  14. Critical Behaviors in a Stochastic Local Limited One-Dimensional Rice-Pile Model

    Institute of Scientific and Technical Information of China (English)

    SUN Hong-Zhang; TANG Zheng-Xin

    2008-01-01

    A stochastic local fimited one-dimensional rice-pile model is numerically investigated. The distributions for ayalanche sizes have a clear power-law behavior and it displays a simple finite size scaling. We obtain the avalanche exponents Ts = 1.54±0.10, βs = 2.17±0.10 and τT = 1.80±0.10, βT = 1.46±0.10. This self-organized critical model belongs to the same universality class with the Oslo rice-pile model studied by K. Christensen et al. [Phys. Rev. Lett. 77 (1996) 107], a rice-pile model studied by L.A.N. Amaral et al. [Phys. Rev. E 54 (1996) 4512], and a simple deterministic self-organized critical model studied by M.S. Vieira [Phys. Rev. E 61 (2000) 6056].

  15. Self-organized criticality revisited: non-local transport by turbulent amplification

    Science.gov (United States)

    Milovanov, A. V.; Rasmussen, J. J.

    2015-12-01

    > We revise the applications of self-organized criticality (SOC) as a paradigmatic model for tokamak plasma turbulence. The work, presented here, is built around the idea that some systems do not develop a pure critical state associable with SOC, since their dynamical evolution involves as a competing key factor an inverse cascade of the energy in reciprocal space. Then relaxation of slowly increasing stresses will give rise to intermittent bursts of transport in real space and outstanding transport events beyond the range of applicability of the `conventional' SOC. Also, we are concerned with the causes and origins of non-local transport in magnetized plasma, and show that this type of transport occurs naturally in self-consistent strong turbulence via a complexity coupling to the inverse cascade. We expect these coupling phenomena to occur in the parameter range of strong nonlinearity and time scale separation when the Rhines time in the system is small compared with the instability growth time.

  16. Higher critical current density achieved in Bi-2223 High-Tc superconductors

    Directory of Open Access Journals (Sweden)

    M.S. Shalaby

    2016-07-01

    Full Text Available Bi2Sr2Ca2Cu3Ox (Bi-2223 were prepared using a solid state reaction method at different sintering times and temperatures. Structural phase identifications have been done using X-Ray analysis and refinement by Reitveld method which proves the coexistence of Bi-2223 and Bi-2212 phases. The critical transition temperature Tc and critical current density Jc values were measured using superconducting quantum interference device magnetometer (SQUID and by the magneto-optics technique. A remarkable rapid decrease to the diamagnetic signal in the magnetization versus temperature M(T at 110 K and Jc around 1.2 × 107 A/m2 at 5 K are confirmed for the Bi-2223 compound.

  17. A nonparametric approach to calculate critical micelle concentrations: the local polynomial regression method.

    Science.gov (United States)

    López Fontán, J L; Costa, J; Ruso, J M; Prieto, G; Sarmiento, F

    2004-02-01

    The application of a statistical method, the local polynomial regression method, (LPRM), based on a nonparametric estimation of the regression function to determine the critical micelle concentration (cmc) is presented. The method is extremely flexible because it does not impose any parametric model on the subjacent structure of the data but rather allows the data to speak for themselves. Good concordance of cmc values with those obtained by other methods was found for systems in which the variation of a measured physical property with concentration showed an abrupt change. When this variation was slow, discrepancies between the values obtained by LPRM and others methods were found.

  18. A nonparametric approach to calculate critical micelle concentrations: the local polynomial regression method

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Fontan, J.L.; Costa, J.; Ruso, J.M.; Prieto, G. [Dept. of Applied Physics, Univ. of Santiago de Compostela, Santiago de Compostela (Spain); Sarmiento, F. [Dept. of Mathematics, Faculty of Informatics, Univ. of A Coruna, A Coruna (Spain)

    2004-02-01

    The application of a statistical method, the local polynomial regression method, (LPRM), based on a nonparametric estimation of the regression function to determine the critical micelle concentration (cmc) is presented. The method is extremely flexible because it does not impose any parametric model on the subjacent structure of the data but rather allows the data to speak for themselves. Good concordance of cmc values with those obtained by other methods was found for systems in which the variation of a measured physical property with concentration showed an abrupt change. When this variation was slow, discrepancies between the values obtained by LPRM and others methods were found. (orig.)

  19. Anisotropy of the critical current in MgB2 tapes made of high energy milled precursor powder

    DEFF Research Database (Denmark)

    Hässler, W.; Kovac, P.; Eisterer, M.;

    2010-01-01

    For applications of MgB2 wires or tapes, high critical currents in high magnetic fields are essential. By using tapes in superconducting coils the anisotropic behaviour of the critical current, i.e. the dependence on the direction of the external field in relation to the tape surface, has...

  20. Large critical current density improvement in Bi-2212 wires through the groove-rolling process

    Science.gov (United States)

    Malagoli, A.; Bernini, C.; Braccini, V.; Romano, G.; Putti, M.; Chaud, X.; Debray, F.

    2013-04-01

    Recently there has been a growing interest in Bi-2212 superconductor round wire for high magnetic field use despite the fact that an increase of the critical current is still needed to boost its successful use in such applications. Recent studies have demonstrated that the main obstacle to current flow, especially in long wires, is the residual porosity inside these powder-in-tube processed conductors that develops from bubble agglomeration when the Bi-2212 melts. In this work we tried to overcome this issue affecting the wire densification by changing the deformation process. Here we show the effects of groove rolling versus the drawing process on the critical current density JC and on the microstructure. In particular, groove-rolled multifilamentary wires show a JC increased by a factor of about 3 with respect to drawn wires prepared with the same Bi-2212 powder and architecture. We think that this approach in the deformation process is able to produce the required improvements both because the superconducting properties are enhanced and because it makes the fabrication process faster and cheaper.

  1. Localized persistent spin currents in defect-free quasiperiodic rings with Aharonov-Casher effect

    Science.gov (United States)

    Qiu, R. Z.; Chen, C. H.; Cheng, Y. H.; Hsueh, W. J.

    2015-06-01

    We propose strongly localized persistent spin current in one-dimensional defect-free quasiperiodic Thue-Morse rings with Aharonov-Casher effect. The results show that the characteristics of these localized persistent currents depend not only on the radius filling factor, but also on the strength of the spin-orbit interaction. The maximum persistent spin currents in systems always appear in the ring near the middle position of the system array whether or not the Thue-Morse rings array is symmetrical. The magnitude of the persistent currents is proportional to the sharpness of the resonance peak, which is dependent on the bandwidth of the allowed band in the band structure. The maximum persistent spin currents also increase exponentially as the generation order of the system increases.

  2. Local governments' roles of the compensation for damage by the Tokai JCO criticality accident

    Energy Technology Data Exchange (ETDEWEB)

    Tanabe, Tomoyuki [Central Research Inst. of Electric Power Industry, Tokyo (Japan). Socio-Economic Research Center

    2003-03-01

    The Tokai JCO criticality accident on September 30, 1999 was the first case to which The Law on Compensation for Nuclear Damage was applied. Although the Law on Compensation for Nuclear Damage formulates the outline of the institutional framework for nuclear third party liability together with operator's insurance scheme, details of actual compensation procedure are not specified. By this reason, the compensation procedure in the Tokai accident had been executed without a concrete legal specification and a precedent. In spite of this situation, the compensation procedure with the accident led to an unexpectedly successful result. We observe the several reasons why the compensation procedure was implemented successfully despite the lack of concrete legal specification and a precedent. One of the reasons is that the local governments, Tokai Village and Ibaraki Prefecture, immediately took the leadership in implementing a temporary regime of compensation procedure without wasting time for waiting national government's directives. Upon practicing this compensation procedure, the local governments implemented the following steps. (1) Initial estimation of the amount and scope of damage. (2) Providing the criteria and heads of damage subject to compensation. (3) Unitary compensation procedure at the local levels. (4) Distribution of emergency payments for the victims. (5) Facilitating compensatory negotiation between the victims and JCO as arbitrator. However, some concerns are also pointed out about the fact that the local government directed the whole procedure without sufficient adjustment with the national government for compensation policy. Among all, in the compensation led by the local governments, it was difficult to guarantee fairness of compensation because victims who are influential on the local government such as industrial associations would have unfairly strong negotiation power in the compensatory negotiation, while the operator being

  3. Dramatic role of critical current anisotropy on flux avalanches in MgB2 films.

    Science.gov (United States)

    Albrecht, J; Matveev, A T; Strempfer, J; Habermeier, H-U; Shantsev, D V; Galperin, Y M; Johansen, T H

    2007-03-16

    Anisotropic penetration of magnetic flux in MgB(2) films grown on vicinal sapphire substrates is investigated using magneto-optical imaging. Regular penetration above 10 K proceeds more easily along the substrate surface steps, the anisotropy of the critical current being 6%. At lower temperatures the penetration occurs via abrupt dendritic avalanches that preferentially propagate perpendicular to the surface steps. This inverse anisotropy in the penetration pattern becomes dramatic very close to 10 K where all flux avalanches propagate in the strongest pinning direction. The observed behavior is fully explained using a thermomagnetic model of the dendritic instability.

  4. Method and composition for improving flux pinning and critical current in superconductors

    Science.gov (United States)

    Morris, Donald E.

    1995-01-01

    Superconducting materials and methods of forming superconducting materials are disclosed. Highly oxidized superconductors are heated at a relatively high temperature so as to release oxygen, which migrates out of the material, and form a non-superconducting phase which does not diffuse out of grains of the material. The material is then reoxidized at a lower temperature, leaving the non-superconducting inclusions inside a superconducting phase. The non-superconducting inclusions act as pinning centers in the superconductor, increasing the critical current thereof.

  5. Temperature dependence of critical current of heterostructures YBCO-STO-LCMO nearly Tc

    CERN Document Server

    Khokhlov, V A; Drobotko, V F; Levchenko, G G; Mikheenko, P N; Chakalov, R; Muirhead, C R

    2003-01-01

    The complex differential susceptibility a pure YBCO film and YBCO-STO-LCMO structures of different STO width (0; 2; 7 nm) is studied. It is shown, that a decrease of superconducting transition temperature T sub o nset and critical current density j sub c is observed, as expected for the structure YBCO-LCMO in comparison with the pure YBCO film. Conversely, the YBCO-STO-LCMO structures display an increase in T sub o nset; as for j sub c , it increases in the structure with 2 nm STO and decreases in that with 7 nm STO. It is suggested the pinning mechanism of vortices undergoes a change with decreasing temperature.

  6. Asymmetry of the critical current and peak effect in superconducting multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Gavrilkin, S Yu; Ivanenko, O M; Lykov, A N; Mitsen, K V; Tsvetkov, A Yu [P N Lebedev Physical Institute, Leninsky prospekt 53, 119991 Moscow (Russian Federation); Attanasio, C; Cirillo, C [CNR-SPIN-Salerno and Dipartimento di Fisica ' E R Caianiello' , Universita degli Studi di Salerno, Fisciano (Saudi Arabia) I-84084 (Italy); Prischepa, S L [Belarus State University of Informatics and Radioelectronics, P Brovka Street 6, Minsk 220013 (Belarus)

    2010-06-15

    The critical current I{sub c} in Nb/NbO and Nb/Pd multilayers with different periods has been investigated in parallel magnetic fields H. The I{sub c}(H) curves were measured for two opposite directions of the bias current I{sub bias} (always oriented perpendicularly to the magnetic field) which causes the motion of the vortices towards the free surface of the sample and the substrate, respectively. For both directions of the current the so-called peak effect has been observed in the I{sub c}(H) dependencies but with a large difference in the absolute values of I{sub c} for the positive and negative directions of I{sub bias}. The position of the peak in the I{sub c}(H) dependencies does not depend on the direction of I{sub bias} and it is shifted towards higher H values when the period of the multilayered structures is increased. These experimental results can be explained by considering the superposition of the applied magnetic field and the field induced by the transport current along the layers which, if the superconducting properties in different Nb layers are non-homogeneous, causes an asymmetric redistribution of the current. The effect is more pronounced when only one superconducting layer has different properties.

  7. Localized excitations in nonlinear complex systems current state of the art and future perspectives

    CERN Document Server

    Cuevas-Maraver, Jesús; Frantzeskakis, Dimitri; Karachalios, Nikos; Kevrekidis, Panayotis; Palmero-Acebedo, Faustino

    2014-01-01

    The study of nonlinear localized excitations is a long-standing challenge for research in basic and applied science, as well as engineering, due to their importance in understanding and predicting phenomena arising in nonlinear and complex systems, but also due to their potential for the development and design of novel applications. This volume is a compilation of chapters representing the current state-of-the-art on the field of localized excitations and their role in the dynamics of complex physical systems.

  8. Microstructural understanding and critical current optimization of advanced high field superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Bonney, L.A.; Willis, T.C.; Larbalestier, D.C.

    1993-01-01

    It is of great importance to improve critical current density, J[sub c] in A15 superconductors for high field magnet applications. Most current work to improve J[sub c] in A15 wires concentrates on increasing the overall J[sub c] by increasing the fraction of superconducting phase in the wire, by improving the uniformity of the superconductor cross section along the length of the wire and by adjusting the strainstate of the A15 layer. The goal of the A15 work in this group was to investigate the intrinsic J[sub c] of the A15 layer itself. To do this, a better understanding of factors controlling the intrinsic J[sub c]of the Nb[sub 3]Sn was pursued.

  9. Local Spin State Measurements in Critically Doped La0 . 83Sr0 . 17CO3

    Science.gov (United States)

    Gulec, Ahmet; Klie, Robert F.

    2014-03-01

    Strontium doped LaCO3 has fascinating magnetic phases which are believed to be directly related to Co spin states. Critically doped La0 . 83 Sr0 . 17 CO3 undergoes a simultaneous Insulator to Metal Transition (IMT) and ferromagnetic (FM) order transition. In this work, we will utilized atomic-resolution Z-contrast imaging, annular bright field (ABF) imaging and electron energy-loss spectroscopy in the aberration-corrected JEOL JEM-ARM200CF in combination with cooling experiments to examine the local magnetic and spin-state transitions in critically doped La0 . 83 Sr0 . 17 CO3 between 80 K and 300 K. Our energy-loss magnetic circular dichroism (EMCD) experiments confirm the non-localized increase in the dichromatic signal at low temperature, associated with a change in the co-ion spin state. On the other hand, by using he ABF imaging, a distortion of the CO6 octahedral and the changes in the Co-O bond lengths within the same unit cell are observed. NSF CAREER Award DMR-0846748

  10. Critical current and flux dynamics in Ag-doped FeSe superconductor

    Science.gov (United States)

    Galluzzi, A.; Polichetti, M.; Buchkov, K.; Nazarova, E.; Mancusi, D.; Pace, S.

    2017-02-01

    The measurements of DC magnetization as a function of the temperature M(T), magnetic field M(H), and time M(t) have been performed in order to compare the superconducting and pinning properties of an undoped FeSe0.94 sample and a silver doped FeSe0.94 + 6 wt% Ag sample. The M(T) curves indicate an improvement of the superconducting critical temperature and a reduction of the non-superconducting phase Fe7Se8 due to the silver doping. This is confirmed by the field and temperature dependent critical current density Jc(H,T) extracted from the superconducting hysteresis loops at different temperatures within the Bean critical state model. Moreover, the combined analysis of the Jc(T) and of the pinning force Fp(H/Hirr) indicate that the pinning mechanisms in both samples can be described in the framework of the collective pinning theory. The U*(T, J) curves show a pinning crossover from an elastic creep regime of intermediate size flux bundles, for low temperatures, to a plastic creep regime at higher temperatures for both the samples. Finally, the vortex hopping attempt time has been evaluated for both samples and the results are comparable with the values reported in the literature for high Tc materials.

  11. Overlooked mountain rock pools in deserts are critical local hotspots of biodiversity.

    Directory of Open Access Journals (Sweden)

    Cândida Gomes Vale

    Full Text Available The world is undergoing exceptional biodiversity loss. Most conservation efforts target biodiversity hotspots at large scales. Such approach overlooks small-sized local hotspots, which may be rich in endemic and highly threatened species. We explore the importance of mountain rock pools (gueltas as local biodiversity hotspots in the Sahara-Sahel. Specifically, we considered how many vertebrates (total and endemics use gueltas, what factors predict species richness, and which gueltas are of most priority for conservation. We expected to provide management recommendations, improve local biodiversity conservation, and simultaneously contribute with a framework for future enhancement of local communities' economy. The identification of local hotspots of biodiversity is important for revaluating global conservation priorities.We quantified the number of vertebrate species from each taxonomic group and endemics present in 69 gueltas in Mauritania, then compared these with species present in a surrounding area and recorded in the country. We evaluated the predictors of species number's present in each guelta through a multiple regression model. We ranked gueltas by their priority for conservation taking into account the percentage of endemics and threats to each guelta. Within a mere aggregate extent of 43 ha, gueltas hold about 32% and 78% of the total taxa analysed and endemics of Mauritania, respectively. The number of species present in each guelta increased with the primary productivity and area of gueltas and occurrence of permanent water. Droughts and human activities threaten gueltas, while 64% of them are currently unprotected.Gueltas are crucial for local biodiversity conservation and human activities. They require urgent management plans in Mauritania's mountains. They could provide refugia under climate change being important for long-term conservation of Sahara-Sahel biodiversity. Given their disproportional importance in relation to their

  12. Overlooked mountain rock pools in deserts are critical local hotspots of biodiversity.

    Science.gov (United States)

    Vale, Cândida Gomes; Pimm, Stuart L; Brito, José Carlos

    2015-01-01

    The world is undergoing exceptional biodiversity loss. Most conservation efforts target biodiversity hotspots at large scales. Such approach overlooks small-sized local hotspots, which may be rich in endemic and highly threatened species. We explore the importance of mountain rock pools (gueltas) as local biodiversity hotspots in the Sahara-Sahel. Specifically, we considered how many vertebrates (total and endemics) use gueltas, what factors predict species richness, and which gueltas are of most priority for conservation. We expected to provide management recommendations, improve local biodiversity conservation, and simultaneously contribute with a framework for future enhancement of local communities' economy. The identification of local hotspots of biodiversity is important for revaluating global conservation priorities. We quantified the number of vertebrate species from each taxonomic group and endemics present in 69 gueltas in Mauritania, then compared these with species present in a surrounding area and recorded in the country. We evaluated the predictors of species number's present in each guelta through a multiple regression model. We ranked gueltas by their priority for conservation taking into account the percentage of endemics and threats to each guelta. Within a mere aggregate extent of 43 ha, gueltas hold about 32% and 78% of the total taxa analysed and endemics of Mauritania, respectively. The number of species present in each guelta increased with the primary productivity and area of gueltas and occurrence of permanent water. Droughts and human activities threaten gueltas, while 64% of them are currently unprotected. Gueltas are crucial for local biodiversity conservation and human activities. They require urgent management plans in Mauritania's mountains. They could provide refugia under climate change being important for long-term conservation of Sahara-Sahel biodiversity. Given their disproportional importance in relation to their size, they are

  13. A route for a strong increase of critical current in nanostrained iron-based superconductors.

    Science.gov (United States)

    Ozaki, Toshinori; Wu, Lijun; Zhang, Cheng; Jaroszynski, Jan; Si, Weidong; Zhou, Juan; Zhu, Yimei; Li, Qiang

    2016-10-06

    The critical temperature Tc and the critical current density Jc determine the limits to large-scale superconductor applications. Superconductivity emerges at Tc. The practical current-carrying capability, measured by Jc, is the ability of defects in superconductors to pin the magnetic vortices, and that may reduce Tc. Simultaneous increase of Tc and Jc in superconductors is desirable but very difficult to realize. Here we demonstrate a route to raise both Tc and Jc together in iron-based superconductors. By using low-energy proton irradiation, we create cascade defects in FeSe0.5Te0.5 films. Tc is enhanced due to the nanoscale compressive strain and proximity effect, whereas Jc is doubled under zero field at 4.2 K through strong vortex pinning by the cascade defects and surrounding nanoscale strain. At 12 K and above 15 T, one order of magnitude of Jc enhancement is achieved in both parallel and perpendicular magnetic fields to the film surface.

  14. Experimental determination of two-dimensional critical current density distribution in YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Amemiya, Naoyuki; Shinkai, Yoshichika [Faculty of Engineering, Yokohama National University, Tokiwadai, Hodogaya, Yokohama (Japan); Iijima, Yasuhiro; Kakimoto, Kazuomi; Takeda, Kaoru [Materials Research Laboratory, Fujikura Ltd., Kiba, Koto, Tokyo (Japan)

    2001-08-01

    The critical current density (J{sub c}) distribution in YBCO coated conductors is attracting interest from the viewpoint of its influence on their AC loss characteristics as well as from material science and process engineering. A two-dimensional J{sub c} distribution in a YBCO coated conductor made by the IBAD (ion-beam assisted deposition) and the PLD (pulse-laser deposition) method can be determined by the magnetic-knife method with spatial resolutions of 0.2 mm lateral and 10 mm longitudinal directions, respectively. In an up-to-date 80A-class YBCO coated conductor, the J{sub c} is relatively uniform in the central part and reaches mbox{l_brace}7$x$10{sup 9} A m{sup -2}, {r_brace} while the J{sub c} fluctuates spatially in the central part of a tape fabricated earlier and with less critical current. Near the edges of the tapes, the J{sub c} is higher or lower than in the central part and the experimentally determined J{sub c} distributions are far from uniform. This suggests that a presumption of a uniform J{sub c} for AC loss estimations is not always reasonable and can lead to a large error in the estimated AC losses. (author)

  15. Critical current retention of potted and unpotted REBCO Roebel cables under transverse pressure and thermal cycling

    Science.gov (United States)

    Talantsev, E. F.; Badcock, R. A.; Mataira, R.; Chong, S. V.; Bouloukakis, K.; Hamilton, K.; Long, N. J.

    2017-04-01

    Coated conductor Roebel cables are an effective way to create a high current density, fully transposed cable. However, despite REBCO tapes being robust against transverse stress, the Roebel architecture can concentrate transverse stress in non-trivial and random patterns depending on the exact arrangement of strands. If stands are embedded in a solid media which consolidates all strands then a transverse stress concentration will not occur. We tested this idea through mechanical and thermo-cycling tests on 5 strand Roebel cables. For non-impregnated cable irreversible degradation in critical currents is initiated at transverse pressures in a range of 4–34 MPa. Optical examination of the cables shows stress concentration patterns beyond those predicted by thickness variations. For cables impregnated with epoxy filled with SiO2 nanopowder, which has a similar thermal expansion coefficient to the metallic substrate of the strands, the irreversibility point is increased above our highest experimentally available pressure of 270 MPa. Thermo-cycling experiments confirmed a closely matched thermal expansion coefficient between the embedding media and metallic substrate is critical to avoid wire failures.

  16. Phase development and critical current density of Bi-2223 tapes fabricated by groove rolling

    Science.gov (United States)

    Iyer, A. N.; Salib, S.; Vipulanandan, C.; Salama, K.; Balachandran, U.

    1999-07-01

    The powder-in-tube technique is the most widely used method for fabricating silver-clad Bi-2223 wires and tapes. In this method the silver billet containing the precursor material is transformed to the final shape using metallurgical deformation techniques such as wire drawing and flat rolling. In the present study, a modified version of the powder-in-tube technique was adopted where the silver billet was reduced in size by groove rolling instead of wire drawing. Microstructural analysis during the initial deformation stage revealed crack formation in the superconductor core. Stress conditions during groove rolling were analysed and appropriate changes were incorporated in the deformation process. After groove rolling the wires were flat rolled to a final thickness of 250 icons/Journals/Common/mu" ALT="mu" ALIGN="TOP"/>m. Subsequent thermomechanical treatment resulted in tapes with critical current density of icons/Journals/Common/approx" ALT="approx" ALIGN="TOP"/>19700 A cm-2 (critical current of icons/Journals/Common/approx" ALT="approx" ALIGN="TOP"/>40 A).

  17. Critical current density measurement of thin films by AC susceptibility based on the penetration parameter h

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiaofen, E-mail: xiaofenli@gmail.com [Materials Research Division, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Grivel, Jean-Claude; Abrahamsen, Asger B.; Andersen, Niels H. [Materials Research Division, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)

    2012-07-15

    We have numerically proved that the dependence of AC susceptibility {chi} of a E(J) power law superconducting thin disc on many parameters can be reduced to one penetration parameter h, with E the electric field and J the current density. Based on this result, we propose a way of measuring the critical current density J{sub c} of superconducting thin films by AC susceptibility. Compared with the normally used method based on the peak of the imaginary part, our method uses a much larger range of the AC susceptibility curve, thus allowing determination of the temperature (T) dependence of J{sub c} from a normally applied {chi}(T) measurement. A fitting equation J{sub c} = 1.9H{sub a} Divides {chi} Prime Divides {sup 0.69}/d, -0.4 < {chi} Prime < -0.001 derived from the critical state case (Bean model) can be used in most situations, where H{sub a} is the amplitude of the applied AC field, {chi} Prime is the real part of the normalized susceptibility and d is the thickness of the film. The method is valid for the cases where the film is fully penetrated. We also discuss how the finite London penetration depth affects the susceptibility when the film is screened. Measurements with varying T, H{sub a} and DC background field H{sub dc} are performed to support the arguments.

  18. Measurement of local current density of all-vanadium redox flow batteries

    Science.gov (United States)

    Hsieh, Wen-Yen; Leu, Chih-Hsing; Wu, Chun-Hsing; Chen, Yong-Song

    2014-12-01

    This article presents a preliminary study of the measurement of local current density in all-vanadium redox flow batteries. Two batteries are designed and manufactured in this study, and the experimental results are compared. In the first cell, the current collector is divided into 25 segments, and the flow field plate is not segmented, whereas in the other cell, the flow field plate is segmented. The effects of the electrolyte flow rate on the battery efficiencies and the local current density variation are investigated. The experimental results show that the current density near the outlet significantly decreases when the discharge capacity approaches zero. In addition, the battery has a larger discharge depth at a higher electrolyte flow rate.

  19. Will current conservation responses save the Critically Endangered Sumatran rhinoceros Dicerorhinus sumatrensis?

    DEFF Research Database (Denmark)

    Havmøller, Rasmus Gren; Payne, Junaidi; Ramono, Widodo

    2016-01-01

    The Critically Endangered Sumatran rhinoceros Dicerorhinus sumatrensis formerly ranged across South-east Asia. Hunting and habitat loss have made it one of the rarest large mammals and the species faces extinction despite decades of conservation efforts. The number of individuals remaining...... is unknown as a consequence of inadequate methods and lack of funds for the intensive field work required to estimate the population size of this rare and solitary species. However, all information indicates that numbers are low and declining. A few individuals persist in Borneo, and three tiny populations...... increased but the species has continued to go locally extinct across its range. Conventional captive breeding has also proven difficult; from a total of 45 Sumatran rhinoceros taken from the wild since 1984 there were no captive births until 2001. Since then only two pairs have been actively bred...

  20. Improved critical current density of MgB2--carbon nanotubes composite.

    Science.gov (United States)

    Shekhar, Chandra; Giri, Rajiv; Malik, S K; Srivastav, O N

    2007-06-01

    In the present study, we report a systematic study of doping/admixing of carbon nanotubes (CNTs) in different concentrations in MgB2. The composite material corresponding to MgB2-x at.% CNTs (35 at.% > or = x > or = 0 at.%) have been prepared by solid-state reaction at ambient pressure. All the samples in the present investigation have been subjected to structural/microstructural characterization employing XRD, Scanning electron microscopic (SEM), and Transmission electron microscopic (TEM) techniques. The magnetization measurements were performed by Physical property measurement system (PPMS) and electrical transport measurements have been done by the four-probe technique. The microstructural investigations reveal the formation of MgB2-carbon nanotube composites. A CNT connecting the MgB2 grains may enhance critical current density due to its size (approximately 5-20 nm diameter) compatible with coherence length of MgB2 (approximately 5-6 nm) and ballistic transport current carrying capability along the tube axis. The transport critical current density (Jct) of MgB2 samples with varying CNTs concentration have been found to vary significantly e.g., Jct of the MgB2 sample with 10 at.% CNT addition is approximately 2.3 x 10(3) A/cm2 and its value for MgB2 sample without CNT addition is approximately 7.2 x 102 A/cm2 at 20 K. In order to study the flux pinning effect of CNTs doping/ admixing in MgB2, the evaluation of intragrain critical current density (JJ) has been carried out through magnetic measurements on the fine powdered version of the as synthesized samples. The optimum result on Jc is obtained for 10 at.% CNTs admixed MgB2 sample at 5 K, the Jc reaches approximately 5.2 x 10(6) A/cm2 in self field, -1.6 x 10(6) A/cm2 at 1 T, approximately 2.9 x 10(5) A/cm2 at 2.6 T, and approximately 3.9 x 10(4) A/cm2 at 4 T. The high value of intragrain Jc in 10 at.% CNTs admixed MgB2 superconductor has been attributed to the incorporation of CNTs into the crystal matrix of

  1. Glueballs in large-N YM by localization on critical points

    CERN Document Server

    Bochicchio, Marco

    2011-01-01

    By exploiting in large-N YM the change of variables from the gauge connection to the ASD part of its curvature by a non-SUSY version of the Nicolai map, we show that certain twistor Wilson loops supported on a Lagrangian submanifold of twistor space are localized on lattices of surface operators of Z(N) holonomy that form translational invariant sectors labelled by the magnetic charge k=1,2,...,N-1 at a point. The localization is obtained reducing the loop equation in the ASD variables in the holomorphic gauge, regularized by analytic continuation to Minkowski space-time, to a critical equation, by exploiting the invariance of the twistor Wilson loops by deformations for the addition of backtracking arcs ending with cusps on the singular divisor of surface operators. Alternatively localization is obtained contracting the YM measure in the ASD variables on the fixed points of a semigroup that acts on the fiber of the Lagrangian twistor fibration which twistor Wilson loops are supported on and leaves invariant ...

  2. Anticoagulant therapy in patients undergoing dental interventions: a critical review of the literature and current perspectives.

    Science.gov (United States)

    Isola, G; Matarese, G; Cordasco, G; Rotondo, F; Crupi, A; Ramaglia, L

    2015-02-01

    Patients treated with oral anticoagulant therapy (OAT) represent an issue to the dentist, as an increasing number of people are using anticoagulant drugs for cardiovascular disease. The choice of an eventual suspension or continuation of anticoagulant therapy is important when considering an efficient management of the patient. Patients in anticoagulant therapy and requiring dental procedures sometimes represent therapeutic concerns especially concerning the suspension of the anticoagulant treatment. At the moment there is no consensus among international experts of a possible discontinuation of therapy before invasive dental procedures. In this paper, the authors try to focus on this topic through a critical review of the literature. Most of the studies suggest the continuation of the anticoagulant treatment with heparin before invasive oral surgical interventions. Based on the data of the literature, two rules must be adopted in clinical practice: 1) maintenance of anticoagulation related to the international normalized ratio (INR); 2) local application of antifibrinolytic agents to ensure a proper hemostatic process. Given the widespread use of anticoagulant drugs in cardiovascular disease, dentists must often face the problem of the therapy and, since there is no consensus on the management of these patients, the authors propose, after a thorough critical review of the literature, the implementation of a multiphase protocol of surgical approach to be implemented with safety in daily clinical practice.

  3. SOME CONSIDERATIONS ON LOCAL FINANCIAL AUTONOMY IN THE CONTEXT OF THE CURRENT FINANCIAL CRISIS

    Directory of Open Access Journals (Sweden)

    Vezure Oana Sabina

    2012-03-01

    Full Text Available Financing of local authorities is currently at the Centre of the political discourse is a daily concern. Romania faces, usually with an attempt to offset the need for control and reduction of public spending with greater financial autonomy of local authorities. At the time, it was searched and searches for a path, a means to achieve a fair distribution of financial resources between the various levels of administration, budget reductions to all of them. If strengthening democracy means to strengthen local autonomy, then it means you have created a system for financing local authorities to be efficient, fair and pointing towards the economic needs of States. In other words, decentralization and local financing and the principle of subsidiarity are mutually dependent. Rightly, the decentralisation of financial management is considered to be the "backbone" of the administrative system of decentralisation, the financial resources being those which are operational link between the needs of local communities and the rules necessary to satisfy them. Thus, the lack of financial resources of the local self-government can result in failure to meet the needs of its members, which at the same time failure of administrative decentralization. The decentralisation of financial management can also be seen as the Government of some specific functions on the line of management authority and the tax revenue to the local public authorities.

  4. Efficient stopping of current-driven domain wall using a local Rashba field

    Science.gov (United States)

    Tatara, Gen; Saarikoski, Henri; Mitsumata, Chiharu

    2016-10-01

    We show theoretically that a locally embedded Rashba interaction acts as a strong pinning center for current-driven domain walls and demonstrate efficient capturing and depinning of the wall using a weak Rashba interaction of the order of 0.01 eV Å. Our discovery is expected to be useful for highly reliable control of domain walls in racetrack memories.

  5. Perineuronal nets increase inhibitory GABAergic currents during the critical period in rats

    Directory of Open Access Journals (Sweden)

    Zheng-Qin Yin

    2013-04-01

    Full Text Available AIM: To investigate inhibitory γ-aminobutyric acid (GABA ergic postsynaptic currents (IPSCs and postsynaptic currents (PSCs in layer IV of the rat visual cortex during the critical period and when plasticity was extended through dissolution of the perineuronal nets (PNNs.METHODS:We employed 24 normal Long-Evans rats to study GABAA-PSC characteristics of neurons within layer IV of the visual cortex during development. The animals were divided into six groups of four rats according to ages at recording:PW3 (P21-23d, PW4 (P28-30d, PW5 (P35-37d, PW6 (P42-44d, PW7 (P49-51d, and PW8 (56-58d. An additional 24 chondroitin sulfate proteoglycan (CSPG degradation rats (also Long-Evans were generated by making a pattern of injections of chondroitinase ABC (chABC into the visual cortex 1 week prior to recording at PW3, PW4, PW5, PW6, PW7, and PW8. Immunohistochemistry was used to identify the effect of chABC injection on CSPGs. PSCswere detected with whole-cell patch recordings, and GABAA receptor-mediated IPSCs were pharmacologically isolated.RESULTS:IPSC peak current showed a strong rise in the age-matched control group, peaked at PW5 and were maintained at a roughly constant value thereafter. Although there was a small increase in peak current for the chABC group with age, the peak currents continued to decrease with the delayed highest value at PW6, resulting in significantly different week-by-week comparison with normal development. IPSC decay time continued to increase until PW7 in the control group, while those in the chABC group were maintained at a stable level after an initial increase at PW4. Compared with normal rats, the decay times recorded in the chABC rats were always shorter, which differed significantly at each age. We did not observe any differences in IPSC properties between the age-matched control and penicillinase (P-ase group.However, the change in IPSCs after chABC treatment was not reflected in the total PSCs or in basic membrane

  6. Critical current densities estimated from AC susceptibilities in proximity-induced superconducting matrix of multifilamentary wire

    Science.gov (United States)

    Akune, Tadahiro; Sakamoto, Nobuyoshi

    2009-03-01

    In a multifilamentary wire proximity-currents between filaments show a close resemblance with the inter-grain current in a high-Tc superconductor. The critical current densities of the proximity-induced superconducting matrix Jcm can be estimated from measured twist-pitch dependence of magnetization and have been shown to follow the well-known scaling law of the pinning strength. The grained Bean model is applied on the multifilamentary wire to obtain Jcm, where the filaments are immersed in the proximity-induced superconducting matrix. Difference of the superconducting characteristics of the filament, the matrix and the filament content factor give a variety of deformation on the AC susceptibility curves. The computed AC susceptibility curves of multifilamentary wires using the grained Bean model are favorably compared with the experimental results. The values of Jcm estimated from the susceptibilities using the grained Bean model are comparable to those estimated from measured twist-pitch dependence of magnetization. The applicability of the grained Bean model on the multifilamentary wire is discussed in detail.

  7. Critical current densities estimated from AC susceptibilities in proximity-induced superconducting matrix of multifilamentary wire

    Energy Technology Data Exchange (ETDEWEB)

    Akune, Tadahiro; Sakamoto, Nobuyoshi, E-mail: akune@te.kyusan-u.ac.j [Department of Electrical Engineering and Information Technology, Kyushu Sangyo University, 2-3-1 Matsukadai, Fukuoka 813-8503 (Japan)

    2009-03-01

    In a multifilamentary wire proximity-currents between filaments show a close resemblance with the inter-grain current in a high-T{sub c} superconductor. The critical current densities of the proximity-induced superconducting matrix J{sub cm} can be estimated from measured twist-pitch dependence of magnetization and have been shown to follow the well-known scaling law of the pinning strength. The grained Bean model is applied on the multifilamentary wire to obtain J{sub cm}, where the filaments are immersed in the proximity-induced superconducting matrix. Difference of the superconducting characteristics of the filament, the matrix and the filament content factor give a variety of deformation on the AC susceptibility curves. The computed AC susceptibility curves of multifilamentary wires using the grained Bean model are favorably compared with the experimental results. The values of J{sub cm} estimated from the susceptibilities using the grained Bean model are comparable to those estimated from measured twist-pitch dependence of magnetization. The applicability of the grained Bean model on the multifilamentary wire is discussed in detail.

  8. The influence of critical current density of Bi-2212 superconductors by defects after Yb-doping

    Science.gov (United States)

    Lu, Tianni; Zhang, Cuiping; Guo, Shengwu; Wu, Yifang; Li, Chengshan; Zhou, Lian

    2015-12-01

    Bi2Sr2Ca1-xYbxCu2O8+δ (Bi-2212) single crystals with x = 0.000, 0.005, 0.010 and 0.020 have been prepared by self-flux method. The influences of Yb doping on the formation of the dislocations in the lattice structures, as well as the related current carrying capability are investigated. Due to the SQUID measurement and the Bean model calculation, the maximum critical current density (Jc) is obtained when the Yb doping content is x = 0.010, though the Tc and the carrier concentration are not in the optimal region. Based on the HRTEM analyses of the Ca-O and Cu-O2 layers, the optimal dislocation density in the Cu-O2 layers is deduced according to the number of the dislocations per unit area. Besides, the sizes of the dislocations also prove the effectiveness of Yb substitution on the enhancement of the current carrying capability in Bi-2212 single crystals.

  9. Enhancement of Local Photovoltaic Current at Ferroelectric Domain Walls in BiFeO3

    Science.gov (United States)

    Yang, Ming-Min; Bhatnagar, Akash; Luo, Zheng-Dong; Alexe, Marin

    2017-02-01

    Domain walls, which are intrinsically two dimensional nano-objects exhibiting nontrivial electronic and magnetic behaviours, have been proven to play a crucial role in photovoltaic properties of ferroelectrics. Despite this recognition, the electronic properties of domain walls under illumination until now have been accessible only to macroscopic studies and their effects upon the conduction of photovoltaic current still remain elusive. The lack of understanding hinders the developing of nanoscale devices based on ferroelectric domain walls. Here, we directly characterize the local photovoltaic and photoconductive properties of 71° domain walls on BiFeO3 thin films with a nanoscale resolution. Local photovoltaic current, proven to be driven by the bulk photovoltaic effect, has been probed over the whole illuminated surface by using a specially designed photoelectric atomic force microscopy and found to be significantly enhanced at domain walls. Additionally, spatially resolved photoconductive current distribution reveals a higher density of excited carriers at domain walls in comparison with domains. Our measurements demonstrate that domain wall enhanced photovoltaic current originates from its high conduction rather than the internal electric field. This photoconduction facilitated local photovoltaic current is likely to be a universal property of topological defects in ferroelectric semiconductors.

  10. Micromagnetic model for studies on Magnetic Tunnel Junction switching dynamics, including local current density

    Energy Technology Data Exchange (ETDEWEB)

    Frankowski, Marek, E-mail: mfrankow@agh.edu.pl; Czapkiewicz, Maciej; Skowronski, Witold; Stobiecki, Tomasz

    2014-02-15

    We present a model introducing the Landau–Lifshitz–Gilbert equation with a Slonczewski's Spin-Transfer-Torque (STT) component in order to take into account spin polarized current influence on the magnetization dynamics, which was developed as an Object Oriented MicroMagnetic Framework extension. We implement the following computations: magnetoresistance of vertical channels is calculated from the local spin arrangement, local current density is used to calculate the in-plane and perpendicular STT components as well as the Oersted field, which is caused by the vertical current flow. The model allows for an analysis of all listed components separately, therefore, the contribution of each physical phenomenon in dynamic behavior of Magnetic Tunnel Junction (MTJ) magnetization is discussed. The simulated switching voltage is compared with the experimental data measured in MTJ nanopillars.

  11. Local and Global Well-Posedness for the Critical Schrodinger-Debye System

    CERN Document Server

    Corcho, Adan J; Silva, Jorge Drumond

    2011-01-01

    We establish local well-posedness results for the Initial Value Problem associated to the Schr\\"odinger-Debye system in dimensions $N=2, 3$ for data in $H^s\\times H^{\\ell}$, with $s$ and $\\ell$ satisfying $\\max \\{0, s-1\\} \\le \\ell \\le \\min\\{2s, s+1\\}$. In particular, these include the energy space $H^1\\times L^2$. Our results improve the previous ones obtained in \\cite{Bidegaray1}, \\cite{Bidegaray2} and \\cite{Corcho-Linares}. Moreover, in the critical case ($N=2$) and for initial data in $H^1\\times L^2$, we prove that solutions exist for all times, thus providing a negative answer to the open problem mentioned in \\cite{Fibich-Papanicolau} concerning the formation of singularities for these solutions.

  12. Critical desertification transition in semi-arid ecosystems: The role of local facilitation and colonization rate

    Science.gov (United States)

    Corrado, Raffaele; Cherubini, Anna Maria; Pennetta, Cecilia

    2015-05-01

    In this work we study the effect of two different ecological mechanisms on the desertification transition in arid or semi-arid ecosystems, modeled by a stochastic cellular automaton. Namely we consider the role of the facilitation mechanism, i.e. the local positive effects of plants on their neighborhood and of colonization factors, such as seed production, survival and germination probabilities. Within the model, the strength of these two mechanisms is determined by the parameters f and b, respectively controlling the rates of the recovery and colonization processes. In particular we focus on the full desertification transition occurring at increasing value of the mortality rate m and we discuss how the values of f and b affect the critical mortality mc , the critical exponents β and γσ‧, determining the power-law scaling of the average vegetation density and of the root-mean-square deviation of the density fluctuations, and the character of the transition: continuous or abrupt. We show that mc strongly depends on both f and b, a dependence which accounts for the higher resilience of the ecosystems to external stresses as a consequence of an increased effectiveness of positive feedback effects. On the other hand, concerning the value of the exponents and the character of the transition, our results point out that both these features are unaffected by changes in the strength of the local facilitation. Viceversa, we show that an increase of the colonization factor b significantly modifies the values of the exponents and the order of the transition, changing a continuous transition into an abrupt one. We explain these results in terms of the different range of the interactions characterizing facilitation and colonization mechanisms.

  13. Treatment of pediculosis capitis: a critical appraisal of the current literature.

    Science.gov (United States)

    Feldmeier, Hermann

    2014-10-01

    Pediculosis capitis is the most common ectoparasitic disease in children in industrialized countries and extremely common in resource-poor communities of the developing world. The extensive use of pediculicides with a neurotoxic mode of action has led to the development and spread of resistant head lice populations all over the world. This triggered the development of compounds with other modes of action. The current literature on treatment approaches of head lice infestation was searched, and published randomized controlled trials were critically analyzed. The following compounds/family of compounds were identified: spinosad, a novel compound with a new neurotoxic mode of action, isopropyl myristate, 1,2-octanediol, ivermectin, plant-based products, and dimeticones. The efficacy and safety of these compounds are reviewed and recommendations for the treatment of pediculosis capitis in individuals as well as the interruption of ongoing epidemics are provided.

  14. Doubled critical current density in Bi-2212 round wires by reduction of the residual bubble density

    Science.gov (United States)

    Jiang, J.; Starch, W. L.; Hannion, M.; Kametani, F.; Trociewitz, U. P.; Hellstrom, E. E.; Larbalestier, D. C.

    2011-08-01

    We have recently shown that the gas present in the only ~ 70% dense filaments of as-drawn Bi-2212 wire agglomerates into large bubbles that fill the entire filament diameter during the melt phase of the heat treatment. Once formed, these bubbles never disappear, although they can be bridged by 2212 grains formed on cooling. In order to test the effect of these bubbles on the critical current Ic, we increased the density of the filaments after drawing using 2 GPa of cold isostatic pressure, finding that the bubble density and size were greatly reduced and that Ic could be at least doubled. We conclude that enhancement of the filament packing density is of great importance for making major Ic improvements in this very useful, round superconducting wire.

  15. Strain induced irreversible critical current degradation in highly dense Bi-2212 round wire

    CERN Document Server

    Bjoerstad, R; Rikel, M.O.; Ballarino, A; Bottura, L; Jiang, J; Matras, M; Sugano, M; Hudspeth, J; Di Michiel, M

    2015-01-01

    The strain induced critical current degradation of overpressure processed straight Bi 2212/Ag wires has been studied at 77 K in self-field. For the first time superconducting properties, lattice distortions, composite wire stress and strain have been measured simultaneously in a high energy synchrotron beamline. A permanent Ic degradation of 5% occurs when the wire strain exceeds 0.60%. At a wire strain of about 0.65% a drastic n value and Ic reduction occur, and the composite stress and the Bi-2212 lattice parameter reach a plateau, indicating Bi-2212 filament fracturing. The XRD measurements show that Bi-2212 exhibits linear elastic behaviour up to the irreversible strain limit.

  16. Fracture behaviors of thin superconducting films with field-dependent critical current density

    Science.gov (United States)

    He, An; Xue, Cun; Yong, Huadong; Zhou, Youhe

    2013-09-01

    The fracture behaviors under electromagnetic force with field-dependent critical current density in thin superconducting film are investigated. Applying finite element method, the energy release rates and stress intensity factors of one central crack versus applied field and crack length are obtained for the Bean model and Kim model. It is interesting that the profile of the stress intensity factor is generally the same as the magnetostrictive behavior during one full cycle applied field. Furthermore, the crack problem of two collinear cracks with respect to crack length and distance is also researched for the Kim model. The results show that the energy release rates and stress intensity factors of the two collinear cracks at left tip and right tip are remarkably different for relatively small crack distance and long crack length. This work can offer good estimations and provide a basis for interpretation of cracking and mechanical failure of HTS thin films in numerous real situations.

  17. Quasi-steady multiple flux tubes induced by localized current perturbation in toroidal plasma

    Science.gov (United States)

    Yun, Gunsu

    2015-11-01

    Quasi-steady helical modes with dual, triple, or more flux tubes are easily produced by localized current drive in the core of sawtoothing plasma on the KSTAR tokamak. Individual flux tubes have m / n = 1 / 1 helicity, co-rotate around the magnetic axis, and later merge into a single m = 1 mode. The merged mode eventually crashes with rapid collapse of the core pressure and the next cycle repeats the same pattern, exhibiting sawtooth-like oscillations in the core pressure. The generation mechanism of multiple flux tubes (MFTs) has been studied in two different approaches to understand the observed trend that the number of flux tubes increases as the current drive location moves away from the magnetic axis up to about the magnetic surface of the safety factor q = 1 at the mode collapse: (1) nonlinear reduced MHD simulation with a localized current source modeling the time-varying interaction between the current source and flux tubes and (2) linear MHD simulation with a prescribed q profile with a radially localized current blip. Both studies show that MFTs can be produced only in plasmas with nearly flat q profile close to unity, suggesting the collapse of the m = 1 mode (i.e., sawtooth crash) is complete. Recent observation of long-lived MFTs induced by localized current drive in non-sawtoothing plasma suggests that q profile evolution toward lower- m instability is required for the merging and crash of MFTs. Work supported by the National Research Foundation of Korea, US D.O.E., and Japan Society for the Promotion of Science.

  18. Evidence for improvement of critical current by Ag in YBaCuO-Ag thick films

    Science.gov (United States)

    Dwir, B.; Kellett, B.; Mieville, L.; Pavuna, D.

    1991-04-01

    The evidence is reported for enhancement of critical current density J(c) in YBa2Cu3O(7-delta) thick films with the addition of Ag, which is correlated with improvements in structural properties. An improvement of 50 percent in J(c) (up to about 500 A/sq cm at T = 4.2 K) was obtained in films made from YBCO + 60 wt pct Ag powder, fabricated by the spin-on technique on (100) SrTiO3, which is correlated with improvements in structure. The resulting films are 10 microns thick, uniform, partially textured, and show good adherence. The critical temperature Tc is improved by the addition of Ag, and a reduction in the density of microcracks and in the amount of secondary phases in the sintered films was observed. Normal-state resistivity is reduced by almost three orders of magnitude, making these films potentially useful for electronic applications in interconnects and novel hybrid circuits.

  19. Evidence for improvement of critical current by Ag in YBaCuO-Ag thick films

    Energy Technology Data Exchange (ETDEWEB)

    Dwir, B.; Kellett, B.; Mieville, L.; Pavuna, D. (Institute of Micro- and Opto-electronics, Department of Physics, Swiss Federal Institute of Technology, CH-1015 Lausanne, Switzerland (CH))

    1991-04-15

    The evidence is reported for enhancement of critical current density {ital J}{sub {ital c}} in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thick films with the addition of Ag, which is correlated with improvements in structural properties. An improvement of 50% in {ital J}{sub {ital c}} (up to {similar to}500 A/cm{sup 2} at {ital T}=4.2 K) was obtained in films made from YBCO+60wt % Ag powder, fabricated by the spin-on technique on (100) SrTiO{sub 3}, which is correlated with improvements in structure. The resulting films are 10 {mu}m thick, uniform, partially textured, and show good adherence. The critical temperature {ital T}{sub {ital c}} is improved by the addition of Ag, and a reduction in the density of microcracks and in the amount of secondary phases in the sintered films was observed. Normal-state resistivity is reduced by almost three orders of magnitude, making these films potentially useful for electronic applications in interconnects and novel hybrid circuits.

  20. High critical current density YBCO films and fabrication of dc-SQUIDs

    CERN Document Server

    Kuriki, S; Kawaguchi, Y; Matsuda, M; Otowa, T

    2002-01-01

    In order to improve the sensitivity of SQUID magnetometers made of high-T sub c films, we have studied the conditions of pulsed-laser deposition of YBCO films. Among the different deposition parameters examined, extensive degassing of the vacuum chamber before and precise control of the substrate temperature during the film deposition were found effective for obtaining high critical temperature T sub c and high critical current density J sub c. It was also found that the residual-resistance ratio has a clear correlation with J sub c , indicating that it can be a good, and easy to measure, index of the film quality. Films having T sub c approx 89-90 K and J sub c >= 5x10 sup 6 A cm sup - sup 2 at 77 K were used to fabricate SQUIDs without a pickup loop. Grain-boundary junctions formed on bicrystal substrates with a 30 deg. misorientation angle exhibited I sub c R sub n values of more than 100 mu V at 77 K. The well-known scaling behaviour of the relation I sub c R sub n propor to (J sup G sup B sub c) sup 1 su...

  1. Critical Development? Using a Critical Theory Lens to Examine the Current Role of Evaluation in the Youth-Development Field

    Science.gov (United States)

    Zeller-Berkman, Sarah

    2010-01-01

    A critical theory lens is used to explore the role of evaluation in youth development, a field aimed at recognizing youth as assets. A theory of change in the field is questioned for its emphasis on individual youth outcomes as programmatic outcome measures. A review of 209 evaluations of 131 programs in the Harvard Family Research Project's…

  2. Direct current stimulation (tDCS) reveals parietal asymmetry in local/global and salience-based selection.

    Science.gov (United States)

    Bardi, Lara; Kanai, Ryota; Mapelli, Daniela; Walsh, Vincent

    2013-03-01

    Data from neuropsychology and neuroimaging studies indicate hemispheric asymmetries in processing object's global form versus local parts. However the attentional mechanisms subtending visual selection of different levels of information are poorly understood. The classical left hemisphere/local-right hemisphere/global dichotomy has been recently challenged by studies linking the asymmetry of activation in the posterior parietal cortex (PPC) with the relative salience of the stimulus rather than with the local/global level. The present study aimed to assess hemispheric asymmetry in local-global and salience-based selection in hierarchical stimuli by using transcranial direct current stimulation (tDCS). To this end, tDCS has been applied to the PPC of both the hemispheres. Our data revealed that tDCS did affect the selection of the target on the basis of its relative salience in a manner that depended on the tDCS polarity applied to the two hemispheres. This result is in line with previous findings that the left PPC is critically involved in attention for low-salience stimuli in the presence of high-salience distractor information, while right PPC is involved in attending to more salient stimuli. Hemispheric asymmetries were also found in local/global selection. Overall the results suggest that neural activation in the PPC is related to both the salience and the level of stimulus representations mediating responses to hierarchical stimuli. The comparison of the results from Experiments 1 and 2 in local/global-based selection suggests that the effect of stimulation could be completely opposite depending on subtle differences in demands of attentional control (sustained attention vs task switching).

  3. Critical current densities in Ag-added bulk MgB{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, M., E-mail: miryala1@shibaura-it.ac.jp [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Inoue, K. [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Koblischka, M.R. [Experimental Physics, Saarland University, Campus C 6 3, 66123 Saarbrücken (Germany); Murakami, M. [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan)

    2015-11-15

    Highlights: • Bulk MgB{sub 2} samples with Ag contents of 0–10 wt% were sintered at 775 °C for 3 h. • Magnetization measurements showed a sharp superconducting transition with T{sub c} (onset) around 38.5–38.7 K. • Atomic force microscopy indicated that Ag-based MgB{sub 2} particles are of nanometer size. • The sample with 4 wt% Ag addition exhibited the highest J{sub c} of 400 kA/cm{sup 2} at 10 K and self field. - Abstract: In previous studies, we found that bulk MgB{sub 2} contained numerous voids in various shapes and sizes. With the aim of improving the critical current density as well as the mechanical performance of the disk-shaped MgB{sub 2} bulk superconductors, we added Ag and optimized the processing conditions. The samples with varied Ag content from 0, 2, 4, 6, to 10 wt% were synthesized in pure Ar atmosphere. Microstructural observation by scanning electron microscopy confirmed that metallic Ag particles are embedded in the void regions. Furthermore, atomic force microscopy indicated that silver-based MgB{sub 2} particles are of nanometer size. As a result, the critical current density (J{sub c}) values were improved with Ag addition as compared to pure MgB{sub 2} bulk. The sample with 4 wt% Ag addition exhibited the highest J{sub c} of 293 kA/cm{sup 2} at 20 K and self field. The respective J{sub c} values at 10 K were 400 kA/cm{sup 2}, 300 kA/cm{sup 2}, and 100 kA/cm{sup 2} in self field, 1 T and 2 T. These values are the highest record values so far reported in bulk MgB{sub 2} materials.

  4. The effects of bending strain on the critical current and AC loss of BSCCO/Ag tapes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guo Min [Center for Advanced Power Systems, Florida State University, Tallahassee, FL 32310 (United States); Schwartz, Justin [Center for Advanced Power Systems, Florida State University, Tallahassee, FL 32310 (United States); Sastry, P V P S S [Center for Advanced Power Systems, Florida State University, Tallahassee, FL 32310 (United States); Lin Liangzhen [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100080 (China); Xiao Liye [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100080 (China); Yu Yunjia [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100080 (China)

    2004-08-01

    When a coil or a winding is made, the superconducting tapes must be bent to different curvatures. Bending of high temperature superconducting (HTS) tapes can result in degradation of the critical current density and thus increase the AC losses of the tapes. Therefore, the effects of bending strain on the critical current and AC loss should be considered in the design of high temperature superconducting apparatus. In this paper, the dependence of critical current and AC loss on the bending diameter of the superconductor tape was experimentally investigated. The diameters of the curved tape were varied from 110 to 36 mm. AC loss measurements were taken at 77 K, 50 Hz. Analysis of the bending strain effects on the critical current and AC loss are presented. An expression describing the dependence of AC losses on bending strain is proposed by modifying Norris' formula. The experimental results are presented and compared with the calculated values.

  5. Correlation of Critical Current Density with Cu3+ Concentration and Density in YBa2Cu3O7-x

    Science.gov (United States)

    Dou, S. X.; Liu, H. K.; Zhou, J. P.; Bourdillon, A. J.; Savvides, N.; Apperley, M.; Gouch, A.; Sorrell, C. C.

    Superconducting YBa2Cu3O7 wires and tapes were fabricated by cold drawing, rolling and extrusion processes. It was found that the critical current density, after O2 equilibration, correlates both with density and Cu3+ concentration. Full density was achieved by using a special heat treatment, but the critical current density was low owing to the low Cu3+ concentration present in this heavily twinned material. The best critical current density results were obtained for material with density of 92-95% of the theoretical value. The low critical current density of the porous specimens is attributed not only to a poor connectivity between grains but also to a low Cu3+ concentration due to the instability of Cu3+ at crystallite surfaces which increase in area with specimen porosity.

  6. The isolated critical value phenomenon in local-global riddling bifurcation

    Institute of Scientific and Technical Information of China (English)

    谭宁; 徐健学; 陈永红

    2002-01-01

    A chaotic synchronized system of two coupled skew tent maps is discussed in this paper. The locally and globallyriddled basins of the chaotic synchronized attractor are studied. It is found that there is a novel phenomenon in thelocal-global riddling bifurcation of the attractive basin of the chaotic synchronized attractor in some specific couplingintervals. The coupling parameter corresponding to the locally riddled basin has a single value which is embeddedin the coupling parameter interval corresponding to the globally riddled basin, just like a breakpoint. Also, there isno relation between this phenomenon and the form of the chaotic synchronized attractor. This phenomenon is foundanalytically. We also try to explain it in a physical sense. It may be that the chaotic synchronized attractor is in thecritical state, as it is infinitely close to the boundary of its attractive basin. We conjecture that this isolated criticalvalue phenomenon will be common in a system with a chaotic attractor in the critical state, in spite of the system beingdiscrete or differential.

  7. Temperature and Magnetic Field Dependence of Critical Current Density of YBCO with Varying Flux Pinning Additions (POSTPRINT)

    Science.gov (United States)

    2010-03-01

    AFRL-RZ-WP-TP-2010-2083 TEMPERATURE AND MAGNETIC FIELD DEPENDENCE OF CRITICAL CURRENT DENSITY OF YBCO WITH VARYING FLUX PINNING ADDITIONS...MAGNETIC FIELD DEPENDENCE OF CRITICAL CURRENT DENSITY OF YBCO WITH VARYING FLUX PINNING ADDITIONS (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b...20 ‒ 77 K. Films were prepared with pulsed laser deposition by (M/ YBCO )N multilayer or ( YBCO )1-x Mx single-target methods, for different M phases

  8. Prospective Analysis of the Current Demand of the Local Labour Market

    Directory of Open Access Journals (Sweden)

    Druzhinina Viktoriya V.

    2014-01-01

    Full Text Available The goal of the article lies in forecasting tendencies of the current demand of the local labour market on the basis of the method of statistical equations of dependencies and correlation and regression analysis for prolongation of relevant processes at the meso-level. The article considers a forecast model for co-ordination of dynamics of vacancies depending on socio-economic indicators of city development, which is formed on the basis of the method of statistical equations. This method requires identification of parameters of equations of single-factor dependencies and ratios of communication stability. On the basis of calculated values of these parameters and on the basis of economic and mathematical modelling of certain macro-economic indicators, the article builds equations of multiple regression, use of which would allow forecasting the current demand in the local labour market in the middle-term perspective. The prospect of further studies is forecasting the level of current balance of the local labour market, using the provided methods for forecasting the current supply.

  9. High critical current density and enhanced irreversibility field in superconducting MgB2 thin films.

    Science.gov (United States)

    Eom, C B; Lee, M K; Choi, J H; Belenky, L J; Song, X; Cooley, L D; Naus, M T; Patnaik, S; Jiang, J; Rikel, M; Polyanskii, A; Gurevich, A; Cai, X Y; Bu, S D; Babcock, S E; Hellstrom, E E; Larbalestier, D C; Rogado, N; Regan, K A; Hayward, M A; He, T; Slusky, J S; Inumaru, K; Haas, M K; Cava, R J

    2001-05-31

    The discovery of superconductivity at 39 K in magnesium diboride offers the possibility of a new class of low-cost, high-performance superconducting materials for magnets and electronic applications. This compound has twice the transition temperature of Nb3Sn and four times that of Nb-Ti alloy, and the vital prerequisite of strongly linked current flow has already been demonstrated. One possible drawback, however, is that the magnetic field at which superconductivity is destroyed is modest. Furthermore, the field which limits the range of practical applications-the irreversibility field H*(T)-is approximately 7 T at liquid helium temperature (4.2 K), significantly lower than about 10 T for Nb-Ti (ref. 6) and approximately 20 T for Nb3Sn (ref. 7). Here we show that MgB2 thin films that are alloyed with oxygen can exhibit a much steeper temperature dependence of H*(T) than is observed in bulk materials, yielding an H* value at 4.2 K greater than 14 T. In addition, very high critical current densities at 4.2 K are achieved: 1 MA cm-2 at 1 T and 105 A cm-2 at 10 T. These results demonstrate that MgB2 has potential for high-field superconducting applications.

  10. Critical evaluation of current developmental toxicity testing strategies: a case of babies and their bathwater.

    Science.gov (United States)

    Carney, Edward W; Ellis, Amy L; Tyl, Rochelle W; Foster, Paul M D; Scialli, Anthony R; Thompson, Kary; Kim, James

    2011-10-01

    This review is the second in a series of four papers emanating from a workshop entitled "Developmental Toxicology-New Directions," which was sponsored by the ILSI Health and Environmental Sciences Institute's (HESI) Developmental and Reproductive Toxicology Technical Committee. The present review analyzes the strengths and weaknesses of current developmental safety testing approaches in an effort to identify those strengths that should be retained in the future versus the weaknesses that should be eliminated. Workshop participants considered the following to be key strengths of current testing approaches: the integrated biology of pregnant animal models including pharmacokinetic and pharmacodynamic processes, the ability to detect low incidence malformations as well as maternally mediated toxicity, and the long history of use coupled with extensive historical data. A number of weaknesses were related to the resource-intensive nature of developmental toxicity testing (e.g., large number of animals, high costs, low throughput, the inability to keep pace with the demand for more toxicity data). Other weaknesses included the use of very high dose levels that often far exceed human exposure levels, the confounding influence of maternal toxicity, sparse understanding of basic developmental mechanisms and genetics of standard animal models relative to mouse or lower organisms, difficulties interpreting low incidence findings, and issues surrounding the interpretation of minor skeletal variations. An appreciation of these strengths and weaknesses is critical for the design of new approaches to developmental toxicity testing in the 21st century. © 2011 Wiley Periodicals, Inc.

  11. Critical current density measurement of thin films by AC susceptibility based on the penetration parameter h

    Science.gov (United States)

    Li, Xiao-Fen; Grivel, Jean-Claude; Abrahamsen, Asger B.; Andersen, Niels H.

    2012-07-01

    We have numerically proved that the dependence of AC susceptibility χ of a E(J) power law superconducting thin disc on many parameters can be reduced to one penetration parameter h, with E the electric field and J the current density. Based on this result, we propose a way of measuring the critical current density Jc of superconducting thin films by AC susceptibility. Compared with the normally used method based on the peak of the imaginary part, our method uses a much larger range of the AC susceptibility curve, thus allowing determination of the temperature (T) dependence of Jc from a normally applied χ(T) measurement. A fitting equation Jc = 1.9Ha∣χ‧∣0.69/d, -0.4 Bean model) can be used in most situations, where Ha is the amplitude of the applied AC field, χ‧ is the real part of the normalized susceptibility and d is the thickness of the film. The method is valid for the cases where the film is fully penetrated. We also discuss how the finite London penetration depth affects the susceptibility when the film is screened. Measurements with varying T, Ha and DC background field Hdc are performed to support the arguments.

  12. Drain current local variability from linear to saturation region in 28 nm bulk NMOSFETs

    Science.gov (United States)

    Karatsori, T. A.; Theodorou, C. G.; Haendler, S.; Dimitriadis, C. A.; Ghibaudo, G.

    2017-02-01

    In this work, we investigate the impact of the source - drain series resistance mismatch on the drain current variability in 28 nm bulk MOSFETs. For the first time, a mismatch model including the local fluctuations of the threshold voltage (Vt), the drain current gain factor (β) and the source - drain series resistance (RSD) in both linear and saturation regions is presented. Furthermore, it is demonstrated that the influence of the source - drain series resistance mismatch is attenuated in the saturation region, due to the weaker sensitivity of the drain current variability on the series resistance variation. The experimental results were further verified by numerical simulations of the drain current characteristics with sensitivity analysis of the MOSFET parameters Vt, β and RSD.

  13. Scapulothoracic bursitis and snapping scapula syndrome: a critical review of current evidence.

    Science.gov (United States)

    Warth, Ryan J; Spiegl, Ulrich J; Millett, Peter J

    2015-01-01

    Symptomatic scapulothoracic disorders, such as painful scapular crepitus and/or bursitis, are uncommon; however, they can produce significant pain and disability in many patients. To review the current knowledge pertaining to snapping scapula syndrome and to identify areas of further research that may be helpful to improve clinical outcomes and patient satisfaction. Systematic review. We performed a preliminary search of the PubMed and Embase databases using the search terms "snapping scapula," "scapulothoracic bursitis," "partial scapulectomy," and "superomedial angle resection" in September 2013. All nonreview articles related to the topic of snapping scapula syndrome were included. The search identified a total of 167 unique articles, 81 of which were relevant to the topic of snapping scapula syndrome. There were 36 case series of fewer than 10 patients, 16 technique papers, 11 imaging studies, 9 anatomic studies, and 9 level IV outcomes studies. The level of evidence obtained from this literature search was inadequate to perform a formal systematic review or meta-analysis. Therefore, a critical review of current evidence is presented. Snapping scapula syndrome, a likely underdiagnosed condition, can produce significant shoulder dysfunction in many patients. Because the precise origin is typically unknown, specific treatments that are effective for some patients may not be effective for others. Nevertheless, bursectomy with or without partial scapulectomy is currently the most effective primary method of treatment in patients who fail nonoperative therapy. However, many patients experience continued shoulder disability even after surgical intervention. Future studies should focus on identifying the modifiable factors associated with poor outcomes after operative and nonoperative management for snapping scapula syndrome in an effort to improve clinical outcomes and patient satisfaction. © 2014 The Author(s).

  14. Theory analysis of critical-current degeneration in bended superconducting tapes of multifilament composite Bi2223/Ag

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Peifeng; Wang, Xingzhe, E-mail: xzwang@lzu.edu.cn

    2015-10-15

    Highlights: • We proposed an empirical model to describe carrying-current degradation of bent Bi2223/Ag tapes. • Asymmetric damage of superconductor multifilament is taken into account. • Both the loading and unloading processes of bend deformation are captured. • Carrying-current property can be improved by designing configuration of the multifilament core. - Abstract: This paper proposed a degradation model to explore the influence of the mechanical bending deformation on the critical-current of superconducting composite Bi2223/Ag tape taking into account the asymmetric mechanical damage. With the aid of Weibull distribution function of statistical damage of filaments, the critical-current dependence upon bending strain of the superconducting tape in processes of loading and unloading is characterized. The degradation profile of critical-current in the superconducting composite tape is theoretically investigated by the proposed model for different critical damage strains and configurations of superconducting multifilament core at the cross-section. It is shown that the theoretical predictions are in reasonably good agreement with the experimental data, and the configuration of the multifilament core of the superconducting composite tape has a significant influence on the critical-current degradation. The superconducting multifilament core located near the compression region of the cross-section remarkably improves the mechanical and carrying-current capabilities of the superconducting composite tape.

  15. [Team approaches to critical bleeding (massive bleeding and transfusion) - chairmen's introductory remarks. Questionnaire survey on current status of hospital clinical laboratories evaluating critical hemorrhage].

    Science.gov (United States)

    Kino, Shuichi; Suwabe, Akira

    2014-12-01

    In 2007, "the Guidelines for Actions against Intraoperative Critical Hemorrhage" were established by the Japanese Society of Anaesthesiologists and the Japanese Society of Blood transfusion and Cell Therapy. The documentation of in-hospital procedures for critical hemorrhage, especially about how to select RBC units, has widely standardized hospital practice. Patients with intraoperative critical hemorrhage sometimes suffer from massive blood loss. In this situation, some patients develop coagulopathy. To treat them, we need to evaluate their coagulation status based on laboratory test results. So, we performed a nationwide questionnaire survey on the current status of hospital clinical laboratories evaluating critical hemorrhage. From the results of this survey, it was recommended that central hospital laboratories should try to reduce the turn-around time required to test for coagulation parameters as much as possible for appropriate substitution therapy. (Review).

  16. Microstructural and crystallographic imperfections of MgB2 superconducting wire and their correlation with the critical current density

    Directory of Open Access Journals (Sweden)

    Mohammed Shahabuddin

    2014-01-01

    Full Text Available A comprehensive study of the effects of structural imperfections in MgB2 superconducting wire has been conducted. As the sintering temperature becomes lower, the structural imperfections of the MgB2 material are increased, as reflected by detailed X-ray refinement and the normal state resistivity. The crystalline imperfections, caused by lattice disorder, directly affect the impurity scattering between the π and σ bands of MgB2, resulting in a larger upper critical field. In addition, low sintering temperature keeps the grain size small, which leads to a strong enhancement of pinning, and thereby, enhanced critical current density. Owing to both the impurity scattering and the grain boundary pinning, the critical current density, irreversibility field, and upper critical field are enhanced. Residual voids or porosities obviously remain in the MgB2, however, even at low sintering temperature, and thus block current transport paths.

  17. Critical current density behaviors across a grain boundary inclined to current with different angles in YBa2Cu3O7-δ bicrystal junctions

    Science.gov (United States)

    Tao, Hua; Wei-Wei, Xu; Zheng-Ming, Ji; Da-Yuan, Guo; Qing-Yun, Wang; Xiang-Rong, Ma; Rui-Yu, Liang

    2016-06-01

    The critical current density behaviors across a bicrystal grain boundary (GB) inclined to the current direction with different angles in YBa2Cu3O7-δ bicrystal junctions in magnetic fields are investigated. There are two main reasons for the difference in critical current density in junctions at different GB inclined angles in the same magnetic field: (i) the GB plane area determines the current carrying cross section; (ii) the vortex motion dynamics at the GB affects the critical current value when the vortex starts to move along the GB by Lorentz force. Furthermore, the vortex motion in a bicrystal GB is studied by investigating transverse (Hall) and longitudinal current-voltage characteristics (I-V xx and I-V xy ). It is found that the I-V xx curve diverges from linearity at a high driving current, while the I-V xy curve keeps nearly linear, which indicates the vortices inside the GB break out of the GB by Lorentz force. Project supported by the National Natural Science Foundation of China (Grant Nos. 61501222, 61371036, and 61571219) and the School Scientific Research Fund of Nanjing Institute of Technology, China (Grant Nos. YKJ201418).

  18. Coupled multiphysics, barrier localization, and critical radius effects in embedded nanowire superlattices

    Science.gov (United States)

    Prabhakar, Sanjay; Melnik, Roderick; Bonilla, Luis L.

    2013-06-01

    The new contribution of this paper is to develop a cylindrical representation of an already known multiphysics model for embedded nanowire superlattices (NWSLs) of wurtzite structure that includes a coupled, strain dependent 8-band k .p Hamiltonian in cylindrical coordinates and investigate the influence of coupled piezo-electromechanical effects on the barrier localization and critical radius in such NWSLs. The coupled piezo-electromechanical model for semiconductor materials takes into account the strain, piezoelectric effects, and spontaneous polarization. Based on the developed 3D model, the band structures of electrons (holes) obtained from results of modeling in Cartesian coordinates are in good agreement with those values obtained from our earlier developed 2D model in cylindrical coordinates. Several parameters such as lattice mismatch, piezo-electric fields, valence, and conduction band offsets at the heterojunction of AlxGa1-xN/GaN superlattice can be varied as a function of the Al mole fraction. When the band offsets at the heterojunction of AlxGa1-xN/GaN are very small and the influence of the piezo-electromechanical effects can be minimized, then the barrier material can no longer be treated as an infinite potential well. In this situation, it is possible to visualize the penetration of the Bloch wave function into the barrier material that provides an estimation of critical radii of NWSLs. In this case, the NWSLs can act as inversion layers. Finally, we investigate the influence of symmetry of the square and cylindrical NWSLs on the band structures of electrons in the conduction band.

  19. Additive Manufacturing Techniques in Prosthodontics: Where Do We Currently Stand? A Critical Review.

    Science.gov (United States)

    Alharbi, Nawal; Wismeijer, Daniel; Osman, Reham B

    The aim of this article was to critically review the current application of additive manufacturing (AM)/3D-printing techniques in prosthodontics and to highlight the influence of various technical factors involved in different AM technologies. A standard approach of searching MEDLINE, EMBASE, and Google Scholar databases was followed. The following search terms were used: (Prosth* OR Restoration) AND (Prototype OR Additive Manufacture* OR Compute* OR 3D-print* OR CAD/CAM) AND (Dentistry OR Dental). Hand searching the reference lists of the included articles and personal connections revealed additional relevant articles. Selection criteria were any article written in English and reporting on the application of AM in prosthodontics from 1990 to February 2016. From a total of 4,290 articles identified, 33 were seen as relevant. Of these, 3 were narrative reviews, 18 were in vitro studies, and 12 were clinical in vivo studies. Different AM technologies are applied in prosthodontics, directly and indirectly for the fabrication of fixed metal copings, metal frameworks for removable partial dentures, and plastic mock-ups and resin patterns for further conventional metal castings. Technical factors involved in different AM techniques influence the overall quality, the mechanical properties of the printed parts, and the total cost and manufacturing time. AM is promising and offers new possibilities in the field of prosthodontics, though its application is still limited. An understanding of these limitations and of developments in material science is crucial prior to considering AM as an acceptable method for the fabrication of dental prostheses.

  20. Critical Current Test of Liquid Hydrogen Cooled HTC Superconductors under External Magnetic Field

    Science.gov (United States)

    Shirai, Yasuyuki; Shiotsu, Masahiro; Tatsumoto, Hideki; Kobayashi, Hiroaki; Naruo, Yoshihiro; Nonaka, Satoshi; Inatani, Yoshifumi

    High-Tc (HTC) superconductors including MgB2 will show excellent properties under temperature of Liquid Hydrogen (LH2:20K), which has large latent heat and low viscosity coefficient. In order to design and fabricate the LH2 cooled superconducting energy devices, we must clear the cooling property of LH2 for superconductors, the cooling system and safety design of LH2 cooled superconducting devices and electro-magnetic property evaluation of superconductors (BSCCO, REBCO and MgB2) and their magnets cooled by LH2. As the first step of the study, an experimental setup which can be used for investigating heat transfer characteristics of LH2 in a pool and also in forced flow (circulation loop with a pump), and also for evaluation of electro-magnetic properties of LH2 cooled superconductors under external magnetic field (up to 7 T). In this paper, we will show a short sketch of the experimental set-up, practical experiences in safety operation of liquid hydrogen cooling system and example test results of critical current evaluation of HTC superconductors cooled by LH2.

  1. High critical current densities in bulk MgB{sub 2} fabricated using amorphous boron

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, Miryala; Kenta, Nozaki; Murakami, Masato [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, Tokyo 135-8548 (Japan); Koblischka, Michael R. [Institute of Experimental Physics, Saarland University, P.O. Box 151150, 66041 Saarbruecken (Germany)

    2015-10-15

    We prepared bulk MgB{sub 2} from high-purity commercial powders of Mg metal (99.9% purity) and amorphous B (99% purity) powders using a single-step solid state reaction at 775 C for varying sintering duration from 1 to 10 h in pure argon atmosphere. X-ray diffraction analysis showed that all the samples were single phase MgB{sub 2}. The magnetization measurements confirmed a sharp superconducting transition with T{sub c,onset} at around 38.2-38.8 K. The critical current density (J{sub c}) values for the MgB{sub 2} samples produced at 1 h sintering time is the highest one in all processed materials here. Scanning electron microscopy analyses indicated that the sintering time has a crucial influence on the grain size. As a result, the highest J{sub c} value of 270 kA cm{sup -2} at 20 K and self-field was achieved in the sample produced at 775 C for 1 h. Our results clearly demonstrate that the optimization of the sintering conditions is essential to improve the bulk MgB{sub 2} performance. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Current status of presurgical infant orthopaedic treatment for cleft lip and palate patients: A critical review

    Science.gov (United States)

    Niranjane, P. Priyanka; Kamble, R. H.; Diagavane, S. Pallavi; Shrivastav, S. Sunita; Batra, Puneet; Vasudevan, S. D.; Patil, Pushkar

    2014-01-01

    Rehabilitation of cleft lip and palate (CLP) patients is a challenge for all the concerned members of the cleft team, and various treatment modalities have been attempted to obtain aesthetic results. Presurgical infant orthopaedics (PSIO) was introduced to reshape alveolar and nasal segments prior to surgical repair of cleft lip. However, literature reports lot of controversy regarding the use of PSIO in patients with CLP. Evaluation of long-term results of PSIO can provide scientific evidence on the efficacy and usefulness of PSIO in CLP patients. The aim was to assess the scientific evidence on the efficiency of PSIO appliances in patients with CLP and to critically analyse the current status of PSIO. A PubMed search was performed using the terms PSIO, presurgical nasoalveolar moulding and its long-term results and related articles were selected for the review. The documented studies report no beneficial effect of PSIO on maxillary arch dimensions, facial aesthetics and in the subsequent development of dentition and occlusion in CLP patients. Nasal moulding seems to be more beneficial and effective in unilateral cleft lip and palate patients with better long-term results. PMID:25593413

  3. Critical Current Oscillations in the Intrinsic Hybrid Vortex State of SmFeAs(O,F)

    Science.gov (United States)

    Moll, Philip J. W.; Balicas, Luis; Zhu, Xiyu; Wen, Hai-Hu; Zhigadlo, Nikolai D.; Karpinski, Janusz; Batlogg, Bertram

    2014-10-01

    In layered superconductors the order parameter may be modulated within the unit cell, leading to nontrivial modifications of the vortex core if the interlayer coherence length ξc(T ) is comparable to the interlayer spacing. In the iron pnictide SmFeAs(O,F) (Tc≈50 K ) this occurs below a crossover temperature T⋆≈41 K , which separates two regimes of vortices: anisotropic Abrikosov-like at high and Josephson-like at low temperatures. Yet in the transition region around T⋆ , hybrid vortices between these two characteristics appear. Only in this region around T⋆ and for magnetic fields well aligned with the FeAs layers, we observe oscillations of the c -axis critical current jc(H ) periodic in 1 /√{H } due to a delicate balance of intervortex forces and interaction with the layered potential. jc(H ) shows pronounced maxima when a hexagonal vortex lattice is commensurate with the underlying crystal structure. The narrow temperature window in which oscillations are observed suggests a significant suppression of the order parameter between the superconducting layers in SmFeAs(O,F), despite its low coherence length anisotropy (γξ≈3 - 5 ).

  4. Atmospheric deposition and critical loads for nitrogen and metals in Arctic Alaska: Review and current status

    Science.gov (United States)

    Linder, Greg L.; Brumbaugh, William G.; Neitlich, Peter; Little, Edward

    2013-01-01

    To protect important resources under their bureau’s purview, the United States National Park Service’s (NPS) Arctic Network (ARCN) has developed a series of “vital signs” that are to be periodically monitored. One of these vital signs focuses on wet and dry deposition of atmospheric chemicals and further, the establishment of critical load (CL) values (thresholds for ecological effects based on cumulative depositional loadings) for nitrogen (N), sulfur, and metals. As part of the ARCN terrestrial monitoring programs, samples of the feather moss Hylocomium splendens are being col- lected and analyzed as a cost-effective means to monitor atmospheric pollutant deposition in this region. Ultimately, moss data combined with refined CL values might be used to help guide future regulation of atmospheric contaminant sources potentially impacting Arctic Alaska. But first, additional long-term studies are needed to determine patterns of contaminant deposition as measured by moss biomonitors and to quantify ecosystem responses at particular loadings/ ranges of contaminants within Arctic Alaska. Herein we briefly summarize 1) current regulatory guidance related to CL values 2) derivation of CL models for N and metals, 3) use of mosses as biomonitors of atmospheric deposition and loadings, 4) preliminary analysis of vulnerabilities and risks associated with CL estimates for N, 5) preliminary analysis of existing data for characterization of CL values for N for interior Alaska and 6) implications for managers and future research needs.

  5. Magnetic Field Dependence of the Critical Current of Planar Geometry Josephson Junctions

    Science.gov (United States)

    Ma, Meng; Cho, Ethan; Huynh, Chuong; Cybart, Shane; Dynes, Robert

    2015-03-01

    We report a study on the magnetic field dependence of the critical current of planar geometry Josephson junctions. We have fabricated Josephson junctions by using a focused helium ion beam to irradiate a narrow barrier in the plane of a 25 nm thick Y-Ba-Cu-O film. The London penetration depth λL is large (~1 μm) because of the ultra-thin thickness of the film. As a result, calculations of the Josephson penetration depth λJ are not realistic nor physical. Therefore in this work, we measure λJ experimentally. We tested devices with bridge widths ranging from 4 to 50 μm, and present measurements of the Fraunhofer quantum diffraction pattern (IC (B)). We observe a crossover from short to long junction behavior, which gives an experimentally measured λJ that ranges between 3 μm to 5 μm. The shape of the IC (B) pattern is strongly affected by the width of the bridge because of self-field effects. As the bridge width increases, Josephson vortices enter the junction and skew the patterns. This work shows that the electronic properties of the planar junctions are very different than those classical ``sandwich'' junctions due to the differences in geometry.

  6. Fracture behaviors of thin superconducting films with field-dependent critical current density

    Energy Technology Data Exchange (ETDEWEB)

    He, An; Xue, Cun; Yong, Huadong; Zhou, Youhe, E-mail: zhouyh@lzu.edu.cn

    2013-09-15

    Highlights: • The fracture behaviors of superconducting films for the Kim model are studied. • The profile of stress intensity factor is generally the same as magnetostriction. • The crack problem of two collinear cracks is also researched for the Kim model. -- Abstract: The fracture behaviors under electromagnetic force with field-dependent critical current density in thin superconducting film are investigated. Applying finite element method, the energy release rates and stress intensity factors of one central crack versus applied field and crack length are obtained for the Bean model and Kim model. It is interesting that the profile of the stress intensity factor is generally the same as the magnetostrictive behavior during one full cycle applied field. Furthermore, the crack problem of two collinear cracks with respect to crack length and distance is also researched for the Kim model. The results show that the energy release rates and stress intensity factors of the two collinear cracks at left tip and right tip are remarkably different for relatively small crack distance and long crack length. This work can offer good estimations and provide a basis for interpretation of cracking and mechanical failure of HTS thin films in numerous real situations.

  7. Field and temperature scaling of the critical current density in commercial REBCO coated conductors

    CERN Document Server

    Senatore, Carmine; Bonura, Marco; Kulich, Miloslav; Mondonico, Giorgio

    2016-01-01

    Scaling relations describing the electromagnetic behaviour of coated conductors (CCs) greatly simplify the design of REBCO-based devices. The performance of REBCO CCs is strongly influenced by fabrication route, conductor architecture and materials, and these parameters vary from one manufacturer to the others. In the present work we have examined the critical surface for the current density, Jc(T,B,θ ), of coated conductors from six different manufacturers: American Superconductor Co. (US), Bruker HTS GmbH (Germany), Fujikura Ltd. (Japan), SuNAM Co. Ltd. (Korea), SuperOx ZAO (Russia) and SuperPower Inc. (US). Electrical transport and magnetic measurements were performed at temperatures between 4.2 K and 77 K and in magnetic field up to 19 T. Experiments were conducted at three different orientations of the field with respect to the crystallographic c-axis of the REBCO layer, θ = 0deg , 45deg and 90deg , in order to probe the angular anisotropy of Jc. In spite of the large variability of CCs performance, ...

  8. Current status of presurgical infant orthopaedic treatment for cleft lip and palate patients: A critical review

    Directory of Open Access Journals (Sweden)

    P Priyanka Niranjane

    2014-01-01

    Full Text Available Rehabilitation of cleft lip and palate (CLP patients is a challenge for all the concerned members of the cleft team, and various treatment modalities have been attempted to obtain aesthetic results. Presurgical infant orthopaedics (PSIO was introduced to reshape alveolar and nasal segments prior to surgical repair of cleft lip. However, literature reports lot of controversy regarding the use of PSIO in patients with CLP. Evaluation of long-term results of PSIO can provide scientific evidence on the efficacy and usefulness of PSIO in CLP patients. The aim was to assess the scientific evidence on the efficiency of PSIO appliances in patients with CLP and to critically analyse the current status of PSIO. A PubMed search was performed using the terms PSIO, presurgical nasoalveolar moulding and its long-term results and related articles were selected for the review. The documented studies report no beneficial effect of PSIO on maxillary arch dimensions, facial aesthetics and in the subsequent development of dentition and occlusion in CLP patients. Nasal moulding seems to be more beneficial and effective in unilateral cleft lip and palate patients with better long-term results.

  9. Local leakage current behaviours of BiFeO3 films

    Institute of Scientific and Technical Information of China (English)

    Zou Cheng; Chen Bin; Zhu Xiao-Jian; Zuo Zheng-Hu; Liu Yi-Wei; Chen Yuan-Fu; Zhan Qing-Feng; Li Run-Wei

    2011-01-01

    The leakage current behaviours of polycrystalline BiFeO3 thin films are investigated by using both conductive atomic force microscopy and current-voltage characteristic measurements.The local charge transport pathways are found to be located mainly at the grain boundaries of the films.The leakage current density can be tuned by changing the post-annealing temperature,the annealing time,the bias voltage and the light illumination,which can be used to improve the performances of the ferroelectric devices based on the BiFeO3 films.A possible leakage mechanism is proposed to interpret the charge transports in the polycrystalline BiFeO3 films.

  10. Evaluation of critical current density and residual resistance ratio limits in powder in tube Nb3Sn conductors

    CERN Document Server

    Segal, Christopher; Sung, Zu Hawn; Lee, Peter J; Sailer, Bernd; Thoener, Manfred; Schlenga, Klaud; Ballarino, Amalia; Bottura, Luca; Bordini, Bernardo; Scheuerlein, Christian; Larnalestier, David C

    2016-01-01

    High critical current density ( Jc) Nb3Sn A15 multifilamentary wires require a large volume fraction of small grain (SG), superconducting A15 phase, as well as Cu stabilizer with high Residual Resistance Ratio (RRR) to provide electromagnetic stabilization and protection. In powder-in-tube (PIT) wires the unreacted Nb7.5 wt%Ta outer layer of the tubular filaments acts as a diffusion barrier and protects the interfilamentary Cu stabilizer from Sn contamination. A high RRR requirement generally imposes a restricted A15 reaction heat treatment to prevent localized full reaction of the filament that could allow Sn to reach the Cu. In this study we investigate recent high quality PIT wires that achieve a Jc (12 T, 4.2 K) up to ∼2500 A mm−2 and find that the minimum diffusion barrier thickness decreases as the filament aspect ratio increases from ∼1 in the inner rings of filaments to 1.3 in the outer filament rings. We found that just 2–3 diffusion barrier breaches can degrade RRR from 300 to 150 or less. U...

  11. Evaluation of critical current density and residual resistance ratio limits in powder in tube Nb3Sn conductors

    CERN Document Server

    Segal, Christopher; Sung, Zu Hawn; Lee, Peter J; Sailer, Bernd; Thoener, Manfred; Schlenga, Klaud; Ballarino, Amalia; Bottura, Luca; Bordini, Bernardo; Scheuerlein, Christian; Larnalestier, David C

    2016-01-01

    High critical current density ( Jc) Nb3Sn A15 multifilamentary wires require a large volume fraction of small grain (SG), superconducting A15 phase, as well as Cu stabilizer with high Residual Resistance Ratio (RRR) to provide electromagnetic stabilization and protection. In powder-in-tube (PIT) wires the unreacted Nb7.5 wt%Ta outer layer of the tubular filaments acts as a diffusion barrier and protects the interfilamentary Cu stabilizer from Sn contamination. A high RRR requirement generally imposes a restricted A15 reaction heat treatment to prevent localized full reaction of the filament that could allow Sn to reach the Cu. In this study we investigate recent high quality PIT wires that achieve a Jc (12 T, 4.2 K) up to ∼2500 A mm−2 and find that the minimum diffusion barrier thickness decreases as the filament aspect ratio increases from ∼1 in the inner rings of filaments to 1.3 in the outer filament rings. We found that just 2–3 diffusion barrier breaches can degrade RRR from 300 to 150 or less. U...

  12. Evaluation of critical current density and residual resistance ratio limits in powder in tube Nb3Sn conductors

    Science.gov (United States)

    Segal, Christopher; Tarantini, Chiara; Hawn Sung, Zu; Lee, Peter J.; Sailer, Bernd; Thoener, Manfred; Schlenga, Klaus; Ballarino, Amalia; Bottura, Luca; Bordini, Bernardo; Scheuerlein, Christian; Larbalestier, David C.

    2016-08-01

    High critical current density (J c) Nb3Sn A15 multifilamentary wires require a large volume fraction of small grain (SG), superconducting A15 phase, as well as Cu stabilizer with high Residual Resistance Ratio (RRR) to provide electromagnetic stabilization and protection. In powder-in-tube (PIT) wires the unreacted Nb7.5 wt%Ta outer layer of the tubular filaments acts as a diffusion barrier and protects the interfilamentary Cu stabilizer from Sn contamination. A high RRR requirement generally imposes a restricted A15 reaction heat treatment to prevent localized full reaction of the filament that could allow Sn to reach the Cu. In this study we investigate recent high quality PIT wires that achieve a J c (12 T, 4.2 K) up to ˜2500 A mm-2 and find that the minimum diffusion barrier thickness decreases as the filament aspect ratio increases from ˜1 in the inner rings of filaments to 1.3 in the outer filament rings. We found that just 2-3 diffusion barrier breaches can degrade RRR from 300 to 150 or less. Using progressive etching of the Cu we also found that the RRR degradation is localized near the external filaments where deformation is highest. Consequently minimizing filament distortion during strand fabrication is important for reducing RRR degradation. The additional challenge of developing the highest possible J c must be addressed by forming the maximum fraction of high J c SG A15 and minimizing low J c large-grain (LG) A15 morphologies. In one wire we found that 15% of the filaments had a significantly enhanced SG/LG A15 ratio and no residual A15 in the core, a feature that opens a path to substantial J c improvement.

  13. Genetic Otx2 mis-localization delays critical period plasticity across brain regions.

    Science.gov (United States)

    Lee, H H C; Bernard, C; Ye, Z; Acampora, D; Simeone, A; Prochiantz, A; Di Nardo, A A; Hensch, T K

    2017-02-14

    Accumulation of non-cell autonomous Otx2 homeoprotein in postnatal mouse visual cortex (V1) has been implicated in both the onset and closure of critical period (CP) plasticity. Here, we show that a genetic point mutation in the glycosaminoglycan recognition motif of Otx2 broadly delays the maturation of pivotal parvalbumin-positive (PV+) interneurons not only in V1 but also in the primary auditory (A1) and medial prefrontal cortex (mPFC). Consequently, not only visual, but also auditory plasticity is delayed, including the experience-dependent expansion of tonotopic maps in A1 and the acquisition of acoustic preferences in mPFC, which mitigates anxious behavior. In addition, Otx2 mis-localization leads to dynamic turnover of selected perineuronal net (PNN) components well beyond the normal CP in V1 and mPFC. These findings reveal widespread actions of Otx2 signaling in the postnatal cortex controlling the maturational trajectory across modalities. Disrupted PV+ network function and deficits in PNN integrity are implicated in a variety of psychiatric illnesses, suggesting a potential global role for Otx2 function in establishing mental health.Molecular Psychiatry advance online publication, 14 February 2017; doi:10.1038/mp.2017.1.

  14. Disaster management and the critical thinking skills of local emergency managers: correlations with age, gender, education, and years in occupation.

    Science.gov (United States)

    Peerbolte, Stacy L; Collins, Matthew Lloyd

    2013-01-01

    Emergency managers must be able to think critically in order to identify and anticipate situations, solve problems, make judgements and decisions effectively and efficiently, and assume and manage risk. Heretofore, a critical thinking skills assessment of local emergency managers had yet to be conducted that tested for correlations among age, gender, education, and years in occupation. An exploratory descriptive research design, using the Watson-Glaser Critical Thinking Appraisal-Short Form (WGCTA-S), was employed to determine the extent to which a sample of 54 local emergency managers demonstrated the critical thinking skills associated with the ability to assume and manage risk as compared to the critical thinking scores of a group of 4,790 peer-level managers drawn from an archival WGCTA-S database. This exploratory design suggests that the local emergency managers, surveyed in this study, had lower WGCTA-S critical thinking scores than their equivalents in the archival database with the exception of those in the high education and high experience group. © 2013 The Author(s). Journal compilation © Overseas Development Institute, 2013.

  15. Enhancement of critical current density in fast neutron irradiated melt-textured YBa 2Cu 3O 7- x

    Science.gov (United States)

    Puźniak, R.; Wiśniewski, A.; Baran, M.; Szymczak, H.; Pingxiang, Zhang; Jingrong, Wang; Lian, Zhou; Pytel, K.; Pytel, B.

    The critical current density in melt-textured samples obtained by the powder melting process was determined from magnetization measurements. Linear dependence between the width of the hysteresis loop and sample size was observed for both unirradiated and irradiated samples. This indicates that the critical current is circulating through the whole sample and is not disconnected by weak links, even when a magnetic field is applied in the irradiated sample. After fast neutron irradiation with fluences from 5 × 10 16 to 6 × 10 17 n cm -2 ( E > 0.5 MeV), significant enhancement of the critical current density, jc, was observed. Critical current density, determined from magnetization measurements, for magnetic field perpendicular to the a-b plane, jcab, reaches - 10 5 A cm 42 at 77 K in 1 T. For H parallel to the a-b plane, jcc along the c-axis reaches 5 × 10 3 A cm -2. An increase in the anisotropy of the critical current was observed after fast neutron irradiation in the temperature range 60 - 80 K.

  16. Systemic and localized scleroderma in children: current and future treatment options.

    Science.gov (United States)

    Rosenkranz, Margalit E; Agle, Lucila M A; Efthimiou, Petros; Lehman, Thomas J A

    2006-01-01

    Scleroderma is a group of rare and complex diseases with varied clinical manifestations. The most obvious manifestation of the diseases is skin hardening and sclerosis. Scleroderma can be divided into two main subgroups: systemic and localized. The systemic form, also known as systemic sclerosis, involves diffuse skin involvement and potentially severe visceral involvement. Localized scleroderma on the other hand is more common in children and usually confined to a specific region of the body with no internal organ involvement. The juvenile forms of systemic sclerosis and localized scleroderma are important conditions in children because of the clinical severity and substantial mortality of systemic scleroderma and the major growth defects associated with childhood-onset localized disease even if the active disease itself is self-limited. The pathogenic pathways of the various forms of scleroderma are only partially defined, but the main defect in scleroderma is abnormal collagen deposition leading to eventual fibrosis in the skin as well as multiple organ systems such as the heart and lungs in juvenile systemic sclerosis. Therapeutics are divided into three main subgroups for systemic sclerosis: antifibrotics, anti-inflammatories, and vasodilators. For localized disease, anti-inflammatories, vitamin D analogs, and UV irradiation have been investigated. However, the infrequency of scleroderma in the pediatric population plus the fact that this disease is very often self-limiting makes randomized controlled trials very difficult. It is for this reason that most data on treatment modalities for this disease have been extrapolated from studies in adult patients. There is no one therapy for systemic sclerosis or localized scleroderma that has proven to be very effective or significantly disease modifying. However, current therapeutic strategies must be initiated early in the disease course for maximum beneficial clinical effects. New interventions such as autologous

  17. A critical period for the recovery of sound localization accuracy following monaural occlusion in the barn owl.

    Science.gov (United States)

    Knudsen, E I; Knudsen, P F; Esterly, S D

    1984-04-01

    We studied the ability of barn owls to recover accurate sound localization after being raised with one ear occluded. Most of the owls had ear plugs inserted before they reached adult size, and therefore they never experienced normal adult localization cues until their ear plugs were removed. Upon removal of their ear plugs, these owls exhibited large systematic sound localization errors. The rate at which they recovered accurate localization decreased with the age of the bird at the time of plug removal, and recovery essentially ceased when owls reached 38 to 42 weeks of age. We interpret this age as the end of a critical period for the consolidation of associations between auditory cues and locations in space. Owls that had experienced adult localization cues for a short period of time before ear plugging recovered normal accuracy rapidly, even if they remained plugged well past the end of the critical period. This suggests that a brief exposure to normal adult cues early in the critical period is sufficient to enable the recovery of localization accuracy much later in life.

  18. Estimation of critical current density and grain connectivity in superconducting MgB 2 bulk using Campbell’s method

    Science.gov (United States)

    Ni, B.; Morita, Y.; Liu, Z.; Liu, C.; Himeki, K.; Otabe, E. S.; Kiuchi, M.; Matsushita, T.

    2008-09-01

    Many recent reports on the critical current density ( Jc) in superconducting MgB 2 bulks indicated that improving the grain connectivity is important, since the obtained Jc values were generally much lower than those in other metallic superconductors and it was ascribed to the poor connectivity between grains in polycrystalline MgB 2. In this study, we focused on the estimation of the global critical current density, super-current path, grain connectivity and their relationships with the faults volume fraction in the MgB 2 bulks prepared by a modified PIT (powder in tube) method. Campbell’s method was applied for the purpose of obtaining the penetrating AC flux profile and the characteristic of AC magnetic field vs. penetration depth from the sample’s surface. A computer simulation on the penetrating AC flux profile in MgB 2 bulks with randomly distributed voids, oxidized grains and other faults was also carried out. Jc obtained by Campbell’s method turned out to be smaller than that obtained from the SQUID measurement, implying that the global super-current was reduced by the existence of various faults and the lack of the electrical connectivity. It was verified that the relationship between the global critical current characteristics and the faults contained in MgB 2 samples can be quantitatively clarified by comparing the simulated critical current densities and other factors with the experimental results.

  19. The influence of post-growth thermal treatments on the critical current density of TSMG YBCO bulk superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Diko, P; Antal, V; Zmorayova, K; Sefcikova, M; Kovac, J [Institute of Experimental Physics SAS, Watsonova 47, 04001 Kosice (Slovakia); Chaud, X [CNRS/CRETA, 25, Avenue des Martyrs, 38042 Grenoble Cedex 9 (France); Yao, X [Department of Physics, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Chen, I [Department of Materials Science and Engineering, National Cheng Kung University (NCKU) Tainan, Taiwan (China); Eisterer, M; Weber, H W [Vienna University of Technology, Atominstitut, Stadionallee 2, 1020 Vienna (Austria)

    2010-12-15

    Oxygenation and thermochemical post-growth treatments of top seeded melt-growth (TSMG) YBCO bulk superconductors can significantly influence critical current density. It is shown that, depending on oxygenation conditions and the size of 211 particles, different reductions of intrinsic critical current density values can be obtained due to the reduction in the sample cross-section caused by the presence of a/b-microcracks induced by 211 particles, and a/b- and a/c-cracks induced by oxygenation. The possibility of eliminating oxygenation cracks by high pressure oxygenation and consequently significantly increasing the macroscopic critical current density is demonstrated. An effective dopant concentration for chemical pinning is proposed and possible clustering of substitutions in the Y123 lattice by thermochemical treatments is shown.

  20. Self-field effects on critical current density and current-voltage characteristics in superconducting YBaCuO thick films

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, A.D.; Hart, C.; Martinez, C.M.; Ares, O. [Superconductivity Lab, IMRE-University of Havana, Vedado 10400, Havana (Cuba)

    1999-07-01

    The self-field and percolative influences on transport measurements of polycrystalline bridges engraved on YBaCuO thick film have been investigated. A maximum in the dependence of the critical current density on cross-sectional area of the bridge (A = 0.003 mm{sup 2}-0.3 mm{sup 2}) has been found experimentally, in samples with low critical current densities (J{sub c}<50 A cm{sup -2}). The result of the measurements are in agreement with Mulet and coworkers, who have predicted that, under certain conditions, the self-field effects on transport measurements are negligible and the J{sub c} dependence on the sample dimensions is determined by the percolative character of the transport current. Self-field influences have also been observed in current-voltage characteristics, which have been analysed using the Ambegaokar-Halperin phase-slip theory. By allowing the noise parameter ({gamma}) to change with temperature, magnetic field and transport current, adequate agreement between theoretical and experimental current-voltage characteristics has been obtained. The dependence of the noise parameter with the transport current is demonstrated to be related with the self-field. (author)

  1. Development of Ti-sheathed MgB{sub 2} wires with high critical current density

    Energy Technology Data Exchange (ETDEWEB)

    Liang, G [Department of Physics, Sam Houston State University, Huntsville, TX 77341 (United States); Fang, H [Department of Physics, Sam Houston State University, Huntsville, TX 77341 (United States); Hanna, M [Department of Mechanical Engineering and Texas Center for Superconductivity, University of Houston, Houston, TX 77204-4006 (United States); Yen, F [Texas Center for Superconductivity, University of Houston, Houston, TX 77204-4006 (United States); Lv, B [Department of Chemistry, University of Houston, Houston, TX 77204-5003 (United States); Alessandrini, M [Department of Mechanical Engineering and Texas Center for Superconductivity, University of Houston, Houston, TX 77204-4006 (United States); Keith, S [Department of Physics, Sam Houston State University, Huntsville, TX 77341 (United States); Hoyt, C [Department of Physics, Sam Houston State University, Huntsville, TX 77341 (United States); Tang, Z [Department of Chemistry, University of Houston, Houston, TX 77204-5003 (United States); Salama, K [Department of Mechanical Engineering and Texas Center for Superconductivity, University of Houston, Houston, TX 77204-4006 (United States)

    2006-11-15

    Working towards developing lightweight superconducting magnets for future space and other applications, we have successfully fabricated mono-core Ti-sheathed MgB{sub 2} wires by the powder-in-tube method. The wires were characterized by magnetization, electrical resistivity, x-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry measurements. The results indicate that the Ti sheath does not react with the magnesium and boron, and the present wire rolling process can produce MgB{sub 2} wires with a superconducting volume fraction of at least 64% in the core. Using the Bean model, it was found that at 5 K, the magnetic critical current densities, J{sub c}, measured in magnetic fields of 0, 5, and 8 T are about 4.2 x 10{sup 5}, 3.6 x 10{sup 4}, and 1.4 x 10{sup 4} A cm{sup -2}, respectively. At 20 K and 0 T, the magnetic J{sub c} is about 2.4 x 10{sup 5} A cm{sup -2}. These results show that at zero and low fields, the values of the magnetic J{sub c} for Ti-sheathed MgB{sub 2} wires are comparable with the best results available for the Fe-sheathed MgB{sub 2} wires. At high fields, however, the J{sub c} for Ti-sheathed MgB{sub 2} wires appears higher than that for the Fe-sheathed MgB{sub 2} wires.

  2. Current practices in the identification of critical habitat for threatened species.

    Science.gov (United States)

    Camaclang, Abbey E; Maron, Martine; Martin, Tara G; Possingham, Hugh P

    2015-04-01

    The term critical habitat is used to describe the subset of habitat that is essential to the survival and recovery of species. Some countries legally require that critical habitat of listed threatened and endangered species be identified and protected. However, there is little evidence to suggest that the identification of critical habitat has had much impact on species recovery. We hypothesized that this may be due at least partly to a mismatch between the intent of critical habitat identification, which is to protect sufficient habitat for species persistence and recovery, and its practice. We used content analysis to systematically review critical habitat documents from the United States, Canada, and Australia. In particular, we identified the major trends in type of information used to identify critical habitat and in occupancy of habitat identified as critical. Information about population viability was used to identify critical habitat for only 1% of the species reviewed, and for most species, designated critical habitat did not include unoccupied habitat. Without reference to population viability, it is difficult to determine how much of a species' occupied and unoccupied habitat will be required for persistence. We therefore conclude that the identification of critical habitat remains inconsistent with the goal of protecting sufficient habitat to support persistence and recovery of the species. Ensuring that critical habitat identification aligns more closely with its intent will improve the accuracy of the designations and may therefore help improve the benefits to species recovery when combined with adequate implementation and enforcement of legal protections. © 2014 Society for Conservation Biology.

  3. Requirements on localized current drive for the suppression of neoclassical tearing modes

    Science.gov (United States)

    Bertelli, N.; De Lazzari, D.; Westerhof, E.

    2011-10-01

    A heuristic criterion for the full suppression of an NTM was formulated as ηNTM ≡ jCD,max/jBS >= 1.2 (Zohm et al 2005 J. Phys. Conf. Ser. 25 234), where jCD,max is the maximum in the driven current density profile applied to stabilize the mode and jBS is the local bootstrap current density. In this work we subject this criterion to a systematic theoretical analysis on the basis of the generalized Rutherford equation. Taking into account only the effect of jCD inside the island, a new criterion for full suppression by a minimum applied total current is obtained in the form of a maximum allowed value for the width of the driven current, wdep, combined with a required minimum for the total driven current in the form of wdepηNTM, where both limits depend on the marginal and saturated island sizes. These requirements can be relaxed when additional effects are taken into account, such as a change in the stability parameter Δ' from the current driven outside the island, power modulation, the accompanying heating inside the island or when the current drive is applied preemptively. When applied to ITER scenario 2, the requirement for full suppression of either the 3/2 or 2/1 NTM becomes wdep ~ 5 cm in agreement with (Sauter et al 2010 Plasma Phys. Control. Fusion 52 025002). Optimization of the ITER ECRH Upper Port Launcher design towards minimum required power for full NTM suppression requires an increase in the toroidal injection angle of the lower steering mirror of several degrees compared with its present design value, while for the upper steering mirror the present design value is close to the optimum.

  4. Effect of Distortion Ratio on Local Scour Under Tidal Currents and Waves

    Institute of Scientific and Technical Information of China (English)

    窦希萍; 董凤舞

    2004-01-01

    Five generalized physical models of different distortion ratios were built according to DOU Guo-ren' s similarity theory of total sediment transport modeling for estuarine and coastal regions. Experiments on local scour in front of groins were made under the actions of tidal currents and waves with clear and sediment entraining water. The scour depths under different dynamic actions are compared. The effect of the distortion ratio on the depth of scour hole is discussed. A relationship between scour depths for distorted and undistorted models is given.

  5. Rainforest pharmacopeia in Madagascar provides high value for current local and prospective global uses.

    Directory of Open Access Journals (Sweden)

    Christopher D Golden

    Full Text Available Botanical diversity provides value to humans through carbon sequestration, air and water purification, and the provisioning of wild foods and ethnomedicines. Here we calculate the value of botanical ethnomedicines in a rainforest region of Madagascar, the Makira Protected Area, using a substitution method that combines replacement costs and choice modeling. The Makira watershed may comprise approximately 0.8% of global botanical diversity and possesses enormous value both in its ability to provision botanical ethnomedicines to local people and as a source of potentially novel pharmaceutical drugs for society as a whole. Approximately 241 locally-recognized species are used as ethnomedicines, including 113 agricultural or weed species. We equated each ethnomedicinal treatment to the monetary value of a comparable pharmaceutical treatment adjusted by personal preferences in perceived efficacy (rather than from known or assumed medicinal equivalency. The benefit value of these botanical ethnomedicines per individual is $5.40-7.90 per year when using the value of highly subsidized Malagasy pharmaceuticals and $100.60-287.40 when using the value of American pharmaceuticals. Using local pharmaceuticals as substitutes, the value per household is $30.24-44.30 per year, equivalent to 43-63% of median annual household income, demonstrating their local importance. Using the value of American pharmaceuticals, the amount is equivalent to 22-63% of the median annual health care expenditures for American adults under 45 in 2006. The potential for developing novel biomedicines from the Makira watershed's unique flora ranges in untapped benefit value from $0.3-5.7 billion for American pharmaceutical companies, non-inclusive of the importance of providing novel medicines and improved healthcare to society. This study provides evidence of the tremendous current local and prospective global value of botanical ethnomedicines and furthers arguments for the

  6. Common Ground of Two Paradigms: Incorporating Critical Theory into Current Art Therapy Practices

    Science.gov (United States)

    Nolan, Emily

    2013-01-01

    Clinical art therapy and studio-based community art therapy represent two major paradigms in art therapy practice. This viewpoint explores how critical theory can be incorporated into both paradigms and result in common ground between them. Critical theory encompasses an understanding of oppression in psychological, social, and cultural contexts…

  7. Common Ground of Two Paradigms: Incorporating Critical Theory into Current Art Therapy Practices

    Science.gov (United States)

    Nolan, Emily

    2013-01-01

    Clinical art therapy and studio-based community art therapy represent two major paradigms in art therapy practice. This viewpoint explores how critical theory can be incorporated into both paradigms and result in common ground between them. Critical theory encompasses an understanding of oppression in psychological, social, and cultural contexts…

  8. Protection of the African Lion: A Critical Analysis of the Current International Legal Regime

    Directory of Open Access Journals (Sweden)

    Samantha Watts

    2016-04-01

    Full Text Available This article looks at the current international regime that pertains to the African lion, a species that needs adequate protection across its range (a range that does not adhere to state boundaries. This analysis comes at a time when threats such as habitat and prey loss, retaliatory killing, trophy hunting and trade, are all impacting the remaining populations of African lions. The species is in danger of rapid population decline and possible extinction in the near future. Two decades ago there was an abundance of African lions, roughly 100 000, on the continent. But at present there are less than 32 000, while some believe there to be as little as 15 000 left. This decline is mainly due to the threats noted above. African lions are currently listed as "vulnerable" on the International Union for Conservation of Nature Red List of Threatened Species. This listing is being contested by commentators who believe that the species now requires an "endangered" status. African lion populations, and the threats to the species, extend across state boundaries. Therefore, international law is of particular importance in providing conservation and protection measures to the species. Creating conservation obligations at a global level allows for more uniform action, implementation and enforcement of legislation at regional and local levels. Therefore this article looks at each threat to African lion populations in detail and then assesses the international legal regime pertaining to each of these threats, and whether that regime is adequate. The Convention on Biological Diversity, Convention on the Conservation of Migratory Species, Convention on International Trade in Endangered Species of Wild Fauna and Flora and the Convention on Wetlands of International Importance are but some of the international instruments that are analysed. This article outlines the arguments that the international legal framework is not acceptable for the protection of the species

  9. Modeling of the Critical-Current Behavior of Nb3Sn Subsized Cables Under Transverse Load Using 2D Finite Element Analysis and a Strain Scaling Law

    CERN Document Server

    Wang, T; Takayasu, M; Bordini, B

    2014-01-01

    The mechanisms causing the critical-current degradation of ITER-type Nb3Sn Cable-in-Conduit-Conductors have been studied in the past decade. One of the origins of the degradation of the performance is the Lorentz load during magnet operations. The strands within the cable subjected to the transverse loads locally experience larger strains than the ones caused by tensile loads. Results obtained with experiments on full size cables are limited due to their cost and difficulty so, to predict the degradations of a Nb3Sn CICC under transverse loads, empirical laws should be established. Strain scaling laws are available but have never been used to determine the behavior of strands under transverse load. We propose a new method, by which the critical-current behavior of a subsized cable under transverse loads is derived from the critical-current behavior under uni-axial strains. This method is based on the strain state of the Nb3Sn filaments obtained by finite element analysis (FEA). The FEA strain results are used...

  10. Instability of current sheets with a localized accumulation of magnetic flux

    Science.gov (United States)

    Pritchett, P. L.

    2015-06-01

    The longstanding problem of whether a current sheet with curved magnetic field lines associated with a small "normal" Bz component is stable is investigated using two-dimensional electromagnetic particle-in-cell simulations, employing closed boundary conditions analogous to those normally assumed in energy principle calculations. Energy principle arguments [Sitnov and Schindler, Geophys. Res. Lett. 37, L08102 (2010)] have suggested that an accumulation of magnetic flux at the tailward end of a thin current sheet could produce a tearing instability. Two classes of such current sheet configurations are probed: one with a monotonically increasing Bz profile and the other with a localized Bz "hump." The former is found to be stable (in 2D) over any reasonable time scale, while the latter is prone to an ideal-like instability that shifts the hump peak in the direction of the curvature normal and erodes the field on the opposite side. The growth rate of this instability is smaller by an order of magnitude than previous suggestions of an instability in an open system. An example is given that suggests that such an unstable hump configuration is unlikely to be produced by external driving of a current sheet with no Bz accumulation even in the presence of open boundary conditions.

  11. Direct evidence for local oscillatory current sources and intracortical phase gradients in turtle visual cortex.

    Science.gov (United States)

    Prechtl, J C; Bullock, T H; Kleinfeld, D

    2000-01-18

    Visual stimuli induce oscillations in the membrane potential of neurons in cortices of several species. In turtle, these oscillations take the form of linear and circular traveling waves. Such waves may be a consequence of a pacemaker that emits periodic pulses of excitation that propagate across a network of excitable neuronal tissue or may result from continuous and possibly reconfigurable phase shifts along a network with multiple weakly coupled neuronal oscillators. As a means to resolve the origin of wave propagation in turtle visual cortex, we performed simultaneous measurements of the local field potential at a series of depths throughout this cortex. Measurements along a single radial penetration revealed the presence of broadband current sources, with a center frequency near 20 Hz (gamma band), that were activated by visual stimulation. The spectral coherence between sources at two well-separated loci along a rostral-caudal axis revealed the presence of systematic timing differences between localized cortical oscillators. These multiple oscillating current sources and their timing differences in a tangential plane are interpreted as the neuronal activity that underlies the wave motion revealed in previous imaging studies. The present data provide direct evidence for the inference from imaging of bidirectional wave motion that the stimulus-induced electrical waves in turtle visual cortex correspond to phase shifts in a network of coupled neuronal oscillators.

  12. Regional estimation of geomagnetically induced currents based on the local magnetic or electric field

    Directory of Open Access Journals (Sweden)

    Viljanen Ari

    2015-01-01

    Full Text Available Previous studies have demonstrated a close relationship between the time derivative of the horizontal geomagnetic field vector (dH/dt and geomagnetically induced currents (GIC at a nearby location in a power grid. Similarly, a high correlation exists between GIC and the local horizontal geoelectric field (E, typically modelled from a measured magnetic field. Considering GIC forecasting, it is not feasible to assume that detailed prediction of time series will be possible. Instead, other measures summarising the activity level over a given period are preferable. In this paper, we consider the 30-min maximum of dH/dt or E as a local activity indicator (|dH/dt|30 or |E|30. Concerning GIC, we use the sum of currents through the neutral leads at substations and apply its 30-min maximum as a regional activity measure (GIC30. We show that |dH/dt|30 at a single point yields a proxy for GIC activity in a larger region. A practical consequence is that if |dH/dt|30 can be predicted at some point then it is also possible to assess the expected GIC level in the surrounding area. As is also demonstrated, |E|30 and GIC30 depend linearly on |dH/dt|30, so there is no saturation with increasing geomagnetic activity contrary to often used activity indices.

  13. Systemic sclerosis and localized scleroderma--current concepts and novel targets for therapy.

    Science.gov (United States)

    Distler, Oliver; Cozzio, Antonio

    2016-01-01

    Systemic sclerosis (SSc) is a chronic autoimmune disease with a high morbidity and mortality. Skin and organ fibrosis are key manifestations of SSc, for which no generally accepted therapy is available. Thus, there is a high unmet need for novel anti-fibrotic therapeutic strategies in SSc. At the same time, important progress has been made in the identification and characterization of potential molecular targets in fibrotic diseases over the recent years. In this review, we have selected four targeted therapies, which are tested in clinical trials in SSc, for in depths discussion of their preclinical characterization. Soluble guanylate cyclase (sGC) stimulators such as riociguat might target both vascular remodeling and tissue fibrosis. Blockade of interleukin-6 might be particularly promising for early inflammatory stages of SSc. Inhibition of serotonin receptor 2b signaling links platelet activation to tissue fibrosis. Targeting simultaneously multiple key molecules with the multityrosine kinase-inhibitor nintedanib might be a promising approach in complex fibrotic diseases such as SSc, in which many partially independent pathways are activated. Herein, we also give a state of the art overview of the current classification, clinical presentation, diagnostic approach, and treatment options of localized scleroderma. Finally, we discuss whether the novel targeted therapies currently tested in SSc could be used for localized scleroderma.

  14. Current trends in local antibacterial therapy of periprosthetic infection and osteomyelitis

    Directory of Open Access Journals (Sweden)

    S. A. Bozhkova

    2015-01-01

    Full Text Available The rational use of antibiotics in the treatment of orthopedic infection still presents a significant problem. Local antibiotic delivery systems enable to achieve effective concentrations of drugs in the focus of bone infection without the development of toxicity. It is the important accompaniment to systemic antibiotics in the treatment of periprosthetic infection and osteomyelitis. The data collected through the PubMed and eLIBRARY databases (http://www.ncbi.nlm. nih.gov/pubmed, 1995-2015; http://elibrary.ru, 2005-2015 years present the information about bone substitutes used for local antibiotic therapy in scientific investigations and in clinical practice. The information is submitted in accordance with the groups of materials: cements based on polymethylmethacrylate, bone grafts, demineralized bone matrix, bioceramics, natural and synthetic polymers, combined antibiotic delivery systems. The majority of these materials have only been studied experimentally and only a limited range of them is registered for use in clinical practice. Informing orthopedic surgeons about current methods of local antibiotic use is the key to the development of a modern integrated approach to the therapy of infectious complications after orthopedic surgery.

  15. Effect of External Magnetic Field on Critical Current for the Onset of Virtual Cathode Oscillations in Relativistic Electron Beams

    CERN Document Server

    Hramov, Alexander E; Morozov, Mikhail; Mushtakov, Alexander

    2008-01-01

    In this Letter we research the space charge limiting current value at which the oscillating virtual cathode is formed in the relativistic electron beam as a function of the external magnetic field guiding the beam electrons. It is shown that the space charge limiting (critical) current decreases with growth of the external magnetic field, and that there is an optimal induction value of the magnetic field at which the critical current for the onset of virtual cathode oscillations in the electron beam is minimum. For the strong external magnetic field the space charge limiting current corresponds to the analytical relation derived under the assumption that the motion of the electron beam is one-dimensional [High Power Microwave Sources. Artech House Microwave Library, 1987. Chapter~13]. Such behavior is explained by the characteristic features of the dynamics of electron space charge in the longitudinal and radial directions in the drift space at the different external magnetic fields.

  16. Localization of endocardial ectopic activity by means of noninvasive endocardial surface current density reconstruction

    Science.gov (United States)

    Lai, Dakun; Liu, Chenguang; Eggen, Michael D.; Iaizzo, Paul A.; He, Bin

    2011-07-01

    Localization of the source of cardiac ectopic activity has direct clinical benefits for determining the location of the corresponding ectopic focus. In this study, a recently developed current-density (CD)-based localization approach was experimentally evaluated in noninvasively localizing the origin of the cardiac ectopic activity from body-surface potential maps (BSPMs) in a well-controlled experimental setting. The cardiac ectopic activities were induced in four well-controlled intact pigs by single-site pacing at various sites within the left ventricle (LV). In each pacing study, the origin of the induced ectopic activity was localized by reconstructing the CD distribution on the endocardial surface of the LV from the measured BSPMs and compared with the estimated single moving dipole (SMD) solution and precise pacing site (PS). Over the 60 analyzed beats corresponding to ten pacing sites (six for each), the mean and standard deviation of the distance between the locations of maximum CD value and the corresponding PSs were 16.9 mm and 4.6 mm, respectively. In comparison, the averaged distance between the SMD locations and the corresponding PSs was slightly larger (18.4 ± 3.4 mm). The obtained CD distribution of activated sources extending from the stimulus site also showed high consistency with the endocardial potential maps estimated by a minimally invasive endocardial mapping system. The present experimental results suggest that the CD method is able to locate the approximate site of the origin of a cardiac ectopic activity, and that the distribution of the CD can portray the propagation of early activation of an ectopic beat.

  17. Current use of imaging and electromagnetic source localization procedures in epilepsy surgery centers across Europe.

    Science.gov (United States)

    Mouthaan, Brian E; Rados, Matea; Barsi, Péter; Boon, Paul; Carmichael, David W; Carrette, Evelien; Craiu, Dana; Cross, J Helen; Diehl, Beate; Dimova, Petia; Fabo, Daniel; Francione, Stefano; Gaskin, Vladislav; Gil-Nagel, Antonio; Grigoreva, Elena; Guekht, Alla; Hirsch, Edouard; Hecimovic, Hrvoje; Helmstaedter, Christoph; Jung, Julien; Kalviainen, Reetta; Kelemen, Anna; Kimiskidis, Vasilios; Kobulashvili, Teia; Krsek, Pavel; Kuchukhidze, Giorgi; Larsson, Pål G; Leitinger, Markus; Lossius, Morten I; Luzin, Roman; Malmgren, Kristina; Mameniskiene, Ruta; Marusic, Petr; Metin, Baris; Özkara, Cigdem; Pecina, Hrvoje; Quesada, Carlos M; Rugg-Gunn, Fergus; Rydenhag, Bertil; Ryvlin, Philippe; Scholly, Julia; Seeck, Margitta; Staack, Anke M; Steinhoff, Bernhard J; Stepanov, Valentin; Tarta-Arsene, Oana; Trinka, Eugen; Uzan, Mustafa; Vogt, Viola L; Vos, Sjoerd B; Vulliémoz, Serge; Huiskamp, Geertjan; Leijten, Frans S S; Van Eijsden, Pieter; Braun, Kees P J

    2016-05-01

    In 2014 the European Union-funded E-PILEPSY project was launched to improve awareness of, and accessibility to, epilepsy surgery across Europe. We aimed to investigate the current use of neuroimaging, electromagnetic source localization, and imaging postprocessing procedures in participating centers. A survey on the clinical use of imaging, electromagnetic source localization, and postprocessing methods in epilepsy surgery candidates was distributed among the 25 centers of the consortium. A descriptive analysis was performed, and results were compared to existing guidelines and recommendations. Response rate was 96%. Standard epilepsy magnetic resonance imaging (MRI) protocols are acquired at 3 Tesla by 15 centers and at 1.5 Tesla by 9 centers. Three centers perform 3T MRI only if indicated. Twenty-six different MRI sequences were reported. Six centers follow all guideline-recommended MRI sequences with the proposed slice orientation and slice thickness or voxel size. Additional sequences are used by 22 centers. MRI postprocessing methods are used in 16 centers. Interictal positron emission tomography (PET) is available in 22 centers; all using 18F-fluorodeoxyglucose (FDG). Seventeen centers perform PET postprocessing. Single-photon emission computed tomography (SPECT) is used by 19 centers, of which 15 perform postprocessing. Four centers perform neither PET nor SPECT in children. Seven centers apply magnetoencephalography (MEG) source localization, and nine apply electroencephalography (EEG) source localization. Fourteen combinations of inverse methods and volume conduction models are used. We report a large variation in the presurgical diagnostic workup among epilepsy surgery centers across Europe. This diversity underscores the need for high-quality systematic reviews, evidence-based recommendations, and harmonization of available diagnostic presurgical methods. Wiley Periodicals, Inc. © 2016 International League Against Epilepsy.

  18. Critical thinking, nurse education and universities: some thoughts on current issues and implications for nursing practice.

    Science.gov (United States)

    Morrall, Peter; Goodman, Benny

    2013-09-01

    When in the latter part of the 20th century nurse 'training' in the UK left the old schools of nursing (based within the health delivery system) and entered universities, the promise was not just a change of focus from training to education but an embracement of 'higher' education. Specifically, nurses were to be exposed to the demands of thinking rather than just doing - and critical thinking at that. However, despite a history of critical perspectives informing nursing theory, that promise may be turning sour. The insidious saturation of the university system in bureaucracy and managerialism has, we argue, undermined critical thinking. A major funding restructuring of higher education in the UK, coinciding with public concern about the state of nursing practice, is undermining further the viability of critical thinking in nursing and potentially the acceptability of university education for nurses. Nevertheless, while critical thinking in universities has decayed, there is no obvious educational alternative that can provide this core attribute, one that is even more necessary to understand health and promote competent nursing practice in an increasingly complex and globalising world. We propose that nurse academics and their colleagues from many other academic and professional disciplines engage in collegiate 'moral action' to re-establish critical thinking in UK universities.

  19. Determining the true polarity and amplitude of synaptic currents underlying gamma oscillations of local field potentials.

    Directory of Open Access Journals (Sweden)

    Gonzalo Martín-Vázquez

    Full Text Available Fluctuations in successive waves of oscillatory local field potentials (LFPs reflect the ongoing processing of neuron populations. However, their amplitude, polarity and synaptic origin are uncertain due to the blending of electric fields produced by multiple converging inputs, and the lack of a baseline in standard AC-coupled recordings. Consequently, the estimation of underlying currents by laminar analysis yields spurious sequences of inward and outward currents. We devised a combined analytical/experimental approach that is suitable to study laminated structures. The approach was essayed on an experimental oscillatory LFP as the Schaffer-CA1 gamma input in anesthetized rats, and it was verified by parallel processing of model LFPs obtained through a realistic CA1 aggregate of compartmental units. This approach requires laminar LFP recordings and the isolation of the oscillatory input from other converging pathways, which was achieved through an independent component analysis. It also allows the spatial and temporal components of pathway-specific LFPs to be separated. While reconstructed Schaffer-specific LFPs still show spurious inward/outward current sequences, these were clearly stratified into distinct subcellular domains. These spatial bands guided the localized delivery of neurotransmitter blockers in experiments. As expected, only Glutamate but not GABA blockers abolished Schaffer LFPs when applied to the active but not passive subcellular domains of pyramidal cells. The known chemical nature of the oscillatory LFP allowed an empirical offset of the temporal component of Schaffer LFPs, such that following reconstruction they yield only sinks or sources at the appropriate sites. In terms of number and polarity, some waves increased and others decreased proportional to the concomitant inputs in native multisynaptic LFPs. Interestingly, the processing also retrieved the initiation time for each wave, which can be used to discriminate

  20. Transport currents along c-axis and (a,b) planes in YBCO single domain materials. Critical current densities and normal-superconducting transitions

    Energy Technology Data Exchange (ETDEWEB)

    Porcar, L.; Bourgault, D.; Chaud, X.; Noudem, J.G.; Tournier, R. [CNRS, Grenoble (France). EPM-Matformag; Belmont, O.; Barbut, J.M.; Barrault, M. [Schneider Electric SA, Usine A, Rue Volta, 38050 Grenoble cedex 09 (France); Tixador, P. [CRTBT, CNRS, BP 166, 38042 Grenoble cedex 09 (France)

    1998-05-01

    High transport currents along the (a,b) planes and along the c-axis have been measured in pulsed current of different pseudo-frequencies. Self field losses and transport current of 8000 A (20000 A cm{sup -2}) have been measured in Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} bars textured by the melting zone technique. Critical currents as high as 500 A (90000 A cm{sup -2}) along the (a,b) planes or 3000 A (7500 A cm{sup -2}) along the c-axis have been measured. For both orientations, the transition from the normal state to the superconducting state has been observed. Electric field of 1000 V m{sup -1} and study of the superconducting state recovery are reported. (orig.) 6 refs.

  1. Critical analysis of the current approaches to modelling educational effectiveness : The importance of establishing a dynamic model

    NARCIS (Netherlands)

    Creemers, B. P. M.; Kyriakides, L.

    2006-01-01

    Researchers in the area of educational effectiveness should attempt to develop a new theoretical framework. A critical analysis of the current models of educational effectiveness research is provided and reveals that a dynamic model of effectiveness must: (a) be multilevel in nature, (b) be based on

  2. Oscillations of critical superconducting current in thin doubly-connected Sn films in an external perpendicular magnetic field

    Science.gov (United States)

    Sivakov, A. G.; Pokhila, A. S.; Glukhov, A. M.; Kuplevakhsky, S. V.; Omelyanchouk, A. N.

    2014-05-01

    We report the results of experimental and theoretical studies of critical current oscillations in thin doubly-connected Sn films in an external perpendicular magnetic field. The experiments were performed on samples that consisted of two wide electrodes joined together by two narrow channels. The length of the channels l satisfied the condition l ≫ ξ (ξ is the Ginzburg-Landau coherence length). At temperatures close to the critical temperature Tc, the dependence of the critical current Ic on average external magnetic flux Φ¯e has the form of a piecewise linear function, periodic with respect to the flux quantum Φ0. The amplitude of the Ic oscillation at a given temperature is proportional to the factor ξ/l. Moreover, the dependence Ic=Ic(Φ ¯e) is found to be multivalued, hence indicating the presence of metastable states. Based on the Ginzburg-Landau approximation, a theory was constructed that explains the above features of the oscillation phenomenon taking a perfectly symmetric system as an example. Further, the experiments displayed the effects related to the critical currents imbalance between the superconducting channels, i.e., shift of the maxima of the dependence Ic=Ic(Φ ¯e) accompanied by an asymmetry with respect to the transport current direction.

  3. Critical current and strand stiffness of three types Nb3Sn strand subjected to spatial periodic bending

    NARCIS (Netherlands)

    Nijhuis, Arend; Ilyin, Y.; Wessel, Wilhelm A.J.; Abbas, Wouter

    2006-01-01

    Knowledge of the influence of bending on the critical current (Ic) of Nb3Sn strands is essential for the understanding of the reduction in performance due to transverse electromagnetic load. In particular, for the large cable-in-conduit conductors (CICCs) meant for the international thermonuclear

  4. Casimir amplitudes and capillary condensation of near-critical fluids between parallel plates: renormalized local functional theory.

    Science.gov (United States)

    Okamoto, Ryuichi; Onuki, Akira

    2012-03-21

    We investigate the critical behavior of a near-critical fluid confined between two parallel plates in contact with a reservoir by calculating the order parameter profile and the Casimir amplitudes (for the force density and for the grand potential). Our results are applicable to one-component fluids and binary mixtures. We assume that the walls absorb one of the fluid components selectively for binary mixtures. We propose a renormalized local functional theory accounting for the fluctuation effects. Analysis is performed in the plane of the temperature T and the order parameter in the reservoir ψ(∞). Our theory is universal if the physical quantities are scaled appropriately. If the component favored by the walls is slightly poor in the reservoir, there appears a line of first-order phase transition of capillary condensation outside the bulk coexistence curve. The excess adsorption changes discontinuously between condensed and noncondensed states at the transition. With increasing T, the transition line ends at a capillary critical point T=T(c) (ca) slightly lower than the bulk critical temperature T(c) for the upper critical solution temperature. The Casimir amplitudes are larger than their critical point values by 10-100 times at off-critical compositions near the capillary condensation line.

  5. Dependence of the critical current density on the first matching field density

    Energy Technology Data Exchange (ETDEWEB)

    Obaidat, I.M. [Department of Physics, United Arab Emirates University, Al-Ain 17551 (United Arab Emirates)], E-mail: iobaidat@uaeu.ac.ae; Benkraouda, M.; Khawaja, U. Al [Department of Physics, United Arab Emirates University, Al-Ain 17551 (United Arab Emirates)

    2008-10-01

    Molecular dynamic simulations were carried out to investigate the properties of the critical depinning force in high temperature superconductors at several vortex densities at the first matching field. The study was conducted on samples with periodic square arrays of vortices and pinning sites. The variables in the simulations were the vortex density, the pinning sites density, the temperature, the pinning strength, the size of pinning sites. The critical depinning force is found to decrease with temperature for all first matching field densities. The rate of this decrease was found to be slower as the pinning strength and size of pinning site gets larger. At low temperatures and for large pinning strengths, the critical depinning force was found to decrease with increasing the first matching field density. But very interesting results were obtained at moderate temperatures where the critical depinning force was found to increase as the first matching field density increases. The same behavior of the critical depinning force was found at low temperatures, for small pinning strengths. These unexpected results were attributed to a vortex structural phase transition from a disordered state to an ordered state.

  6. Choice of sample size for high transport critical current density in a granular superconductor: percolation versus self-field effects

    Energy Technology Data Exchange (ETDEWEB)

    Mulet, R.; Diaz, O.; Altshuler, E. [Superconductivity Laboratory, IMRE-Physics Faculty, University of Havana, La Habana (Cuba)

    1997-10-01

    The percolative character of the current paths and the self-field effects were considered to estimate optimal sample dimensions for the transport current of a granular superconductor by means of a Monte Carlo algorithm and critical-state model calculations. We showed that, under certain conditions, self-field effects are negligible and the J{sub c} dependence on sample dimensions is determined by the percolative character of the current. Optimal dimensions are demonstrated to be a function of the fraction of superconducting phase in the sample. (author)

  7. Field-dependent critical state of high-Tc superconducting strip simultaneously exposed to transport current and perpendicular magnetic field

    Science.gov (United States)

    Xue, Cun; He, An; Yong, Huadong; Zhou, Youhe

    2013-12-01

    We present an exact analytical approach for arbitrary field-dependent critical state of high-Tc superconducting strip with transport current. The sheet current and flux-density profiles are derived by solving the integral equations, which agree with experiments quite well. For small transport current, the approximate explicit expressions of sheet current, flux-density and penetration depth for the Kim model are derived based on the mean value theorem for integration. We also extend the results to the field-dependent critical state of superconducting strip in the simultaneous presence of applied field and transport current. The sheet current distributions calculated by the Kim model agree with experiments better than that by the Bean model. Moreover, the lines in the Ia-Ba plane for the Kim model are not monotonic, which is quite different from that the Bean model. The results reveal that the maximum transport current in thin superconducting strip will decrease with increasing applied field which vanishes for the Bean model. The results of this paper are useful to calculate ac susceptibility and ac loss.

  8. Field-dependent critical state of high-Tc superconducting strip simultaneously exposed to transport current and perpendicular magnetic field

    Directory of Open Access Journals (Sweden)

    Cun Xue

    2013-12-01

    Full Text Available We present an exact analytical approach for arbitrary field-dependent critical state of high-Tc superconducting strip with transport current. The sheet current and flux-density profiles are derived by solving the integral equations, which agree with experiments quite well. For small transport current, the approximate explicit expressions of sheet current, flux-density and penetration depth for the Kim model are derived based on the mean value theorem for integration. We also extend the results to the field-dependent critical state of superconducting strip in the simultaneous presence of applied field and transport current. The sheet current distributions calculated by the Kim model agree with experiments better than that by the Bean model. Moreover, the lines in the Ia-Ba plane for the Kim model are not monotonic, which is quite different from that the Bean model. The results reveal that the maximum transport current in thin superconducting strip will decrease with increasing applied field which vanishes for the Bean model. The results of this paper are useful to calculate ac susceptibility and ac loss.

  9. Field-dependent critical state of high-Tc superconducting strip simultaneously exposed to transport current and perpendicular magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Cun; He, An; Yong, Huadong; Zhou, Youhe, E-mail: zhouyh@lzu.edu.cn [Key Laboratory of Mechanics on Disaster and Environment in Western China attached to the Ministry of Education of China, and Department of Mechanics and Engineering Sciences, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)

    2013-12-15

    We present an exact analytical approach for arbitrary field-dependent critical state of high-T{sub c} superconducting strip with transport current. The sheet current and flux-density profiles are derived by solving the integral equations, which agree with experiments quite well. For small transport current, the approximate explicit expressions of sheet current, flux-density and penetration depth for the Kim model are derived based on the mean value theorem for integration. We also extend the results to the field-dependent critical state of superconducting strip in the simultaneous presence of applied field and transport current. The sheet current distributions calculated by the Kim model agree with experiments better than that by the Bean model. Moreover, the lines in the I{sub a}-B{sub a} plane for the Kim model are not monotonic, which is quite different from that the Bean model. The results reveal that the maximum transport current in thin superconducting strip will decrease with increasing applied field which vanishes for the Bean model. The results of this paper are useful to calculate ac susceptibility and ac loss.

  10. Anticonvulsant pharmacotherapy for generalized and localized vulvodynia : a critical review of the literature

    NARCIS (Netherlands)

    Spoelstra, Symen K.; Borg, Charmaine; Schultz, Willibrord C. M. Weijmar

    Anticonvulsant therapy has occasionally been recommended to treat vulvodynia. However, convincing evidence to support this therapeutic option is lacking. The goal of this study was to critically review studies published on the effectiveness of anticonvulsants for the treatment of vulvodynia.

  11. Critical currents in ballistic two-dimensional InAs-based superconducting weak links

    NARCIS (Netherlands)

    Heida, J.P.; Wees, B.J. van; Klapwijk, T.M.; Borghs, G.

    1999-01-01

    The critical supercurrent Ic carried by a short (0.3 to 0.8 µm) ballistic two-dimensional InAs-based electron gas between superconducting niobium electrodes is studied. In relating the maximum value to the resistance of the weak link in the normal state Rn a much lower value is found than

  12. A study of enhancing critical current densities (J(sub c)) and critical temperature (T(sub c)) of high-temperature superconductors

    Science.gov (United States)

    Vlasse, Marcus

    1992-01-01

    The development of pure phase 123 and Bi-based 2223 superconductors has been optimized. The pre-heat processing appears to be a very important parameter in achieving optimal physical properties. The synthesis of pure phases in the Bi-based system involves effects due to oxygen partial pressure, time, and temperature. Orientation/melt-sintering effects include the extreme c-axis orientation of Yttrium 123 and Bismuth 2223, 2212, and 2201 phases. This orientation is conductive to increasing critical currents. A procedure was established to substitute Sr for Ba in Y-123 single crystals.

  13. Critical line of the Φ4 scalar field theory on a 4D cubic lattice in the local potential approximation

    Directory of Open Access Journals (Sweden)

    J.-M. Caillol

    2013-01-01

    Full Text Available We establish the critical line of the one-component Φ4 (or Landau-Ginzburg model on a simple four dimensional cubic lattice. Our study is performed in the framework of the non-perturbative renormalization group in the local potential approximation with a soft infra-red regulator. The transition is found to be of second order even in the Gaussian limit where first order would be expected according to some recent theoretical predictions.

  14. Pseudoelasticity of NiTi Orthodontic Wires Modified by Current Methodologies : A Critical Comparison

    OpenAIRE

    Airoldi, G.; Riva, G

    1995-01-01

    It is well known that applications of NiTi alloys in orthodontics rely on the pseudoelastic properties developed at temperatures higher than Af. That implies as a necessary condition that the body temperature (Tb) be higher than Af ; the level of reversion stress, σr depends moreover upon the difference between Tb and Af. Nowadays the interest is directed to obtain an archwire with distinct σr in different segments : that means to modify locally the properties of the wire by local thermal tre...

  15. Dynamics of the east India coastal current. 1. Analytic solutions forced by interior Ekman pumping and local alongshore winds

    Digital Repository Service at National Institute of Oceanography (India)

    Shankar, D.; McCreary, J.P.; Han, W.; Shetye, S.R.

    OF GEOPHYSICAL RESEARCH, VOL. 101, NO. C6, PAGES 13,975-13,991, JUNE 15, 1996 Dynamics of the East India Coastal Current 1. Analytic solutions forced by interior Ekman pumping and local alongshore winds D. Snankar Centre for Mathematical Modelling... linear, continuously stratified model is used to investigate how forcing by interior Ekman pumping and local alongshore winds affects the East India Coastal Current (EICC). Solutions are found analytically to an approximate version of the equations...

  16. Spin torque and critical currents for magnetic vortex nano-oscillator in nanopillars

    Energy Technology Data Exchange (ETDEWEB)

    Guslienko, K Y; Gonzalez, J [Dpto. Fisica de Materiales, Universidad del Pais Vasco, 20018 Donostia-San Sebastian (Spain); Aranda, G R, E-mail: sckguslk@ehu.es [Centro de Fisica de Materiales UPV/EHU-CSIC, 20018 San Sebastian (Spain)

    2011-04-01

    We calculated the main dynamic parameters of the spin polarized current induced magnetic vortex oscillations in nanopillars, such as the range of current density, where vortex steady oscillations exist, the oscillation frequency and orbit radius. We accounted for both the non-linear vortex frequency and non-linear vortex damping. To describe the vortex excitations by the spin polarized current we used a generalized Thiele approach to motion of the vortex core as a collective coordinate. All the calculation results are represented via the free layer sizes, saturation magnetization, and the Gilbert damping. Predictions of the developed model can be checked experimentally.

  17. Spatial periodic contact stress and critical current of a Nb3Sn strand measured in TARSIS

    NARCIS (Netherlands)

    Nijhuis, Arend; Ilyin, Y.; Wessel, Wilhelm A.J.

    2006-01-01

    We have developed a new probe for testing the influence of local contact load from crossing superconducting Nb3Sn strands. The probe is part of the TARSIS setup for strand stress–strain characterization. The results from the TARSIS setup with different probes developed for the characterization of

  18. Hypersensitive reactions to local dental anesthetics and patient information: critical review of a drug leaflet

    Directory of Open Access Journals (Sweden)

    Simonet D

    2011-09-01

    Full Text Available Daniel Simonet School of Business and Management, American University of Sharjah, Sharjah, United Arab Emirates Abstract: This paper discusses the case of a patient who experienced adverse reactions to a local anesthetic. It reviews symptoms of adverse reactions, possible causes, patient management, and alternative anesthesia modes. The second part of the paper discusses the product leaflet information and the associated legal issues. Keywords: hypersensitive reactions, local dental anesthetics, patient information

  19. Critical current densities and irreversibility fields of MgB 2 bulks

    Science.gov (United States)

    Kumakura, H.; Takano, Y.; Fujii, H.; Togano, K.; Kito, H.; Ihara, H.

    2001-11-01

    We prepared two MgB 2 bulks by applying conventional sintering and high-pressure sintering methods, and compared the current carrying properties. Jc obtained by the resistive method was larger than that obtained by the magnetic method. Jc- B curves obtained by the resistive method showed no history effect. These results indicate that most of the superconducting currents flowing in the MgB 2 bulks were intergrain (transport) currents and intragrain currents were negligibly small. The high-pressure sintered sample with smaller grain size showed smaller field dependence of Jc and higher Birr than the conventionally sintered sample with larger grain size. This behavior can be explained by the grain boundary flux pinning.

  20. Temperature dependence of the critical current of the superconducting microladder in zero magnetic field: Theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Fink, H.J. (Department of Electrical Engineering and Computer Science, University of California, Davis, Davis, California 95616 (USA)); Buisson, O.; Pannetier, B. (Centre de Recherches sur les Tres Basses Temperature, Centre National de la Recherche Scientifique, Boite Postale 166X, 38042 Grenoble CEDEX, France (FR))

    1991-05-01

    The largest supercurrent which can be injected into a superconducting microladder was calculated as a function of nodal spacing {ital scrL} and temperature for zero magnetic flux using (i) exact solutions of the Ginzburg-Landau equation in terms of Jacobian elliptic functions and (ii) approximate solutions in terms of hyperbolic functions. The agreement is good for {ital scrL}/{xi}({ital T}){lt}3, where {xi}({ital T}) is the temperature-dependent coherence length. Since solution (ii) is much simpler than solution (i), it is of considerable value when calculating critical currents of micronets with nodal spacings comparable to {xi}({ital T}). We find that the temperature-dependent critical current deviates significantly from the classical 3/2 power law of the Ginzburg-Landau theory. Preliminary experiments on a submicrometer ladder confirm such deviations.

  1. Exploring local adaptation and the ocean acidification seascape – studies in the California Current Large Marine Ecosystem

    Directory of Open Access Journals (Sweden)

    G. E. Hofmann

    2013-07-01

    Full Text Available The California Current Large Marine Ecosystem (CCLME, a temperate marine region dominated by episodic upwelling, is predicted to experience rapid environmental change in the future due to ocean acidification. Aragonite saturation state within the California Current System is predicted to decrease in the future, with near-permanent undersaturation conditions expected by the year 2050. Thus, the CCLME is a critical region to study due to the rapid rate of environmental change that resident organisms will experience and because of the economic and societal value of this coastal region. Recent efforts by a research consortium – the Ocean Margin Ecosystems Group for Acidification Studies (OMEGAS – has begun to characterize a portion of the CCLME; both describing the mosaic of pH in coastal waters and examining the responses of key calcification-dependent benthic marine organisms to natural variation in pH and to changes in carbonate chemistry that are expected in the coming decades. In this review, we present the OMEGAS strategy of co-locating sensors and oceanographic observations with biological studies on benthic marine invertebrates, specifically measurements of functional traits such as calcification-related processes and genetic variation in populations that are locally adapted to conditions in a particular region of the coast. Highlighted in this contribution are (1 the OMEGAS sensor network that spans the west coast of the US from central Oregon to southern California, (2 initial findings of the carbonate chemistry amongst the OMEGAS study sites, (3 an overview of the biological data that describes the acclimatization and the adaptation capacity of key benthic marine invertebrates within the CCLME.

  2. Empathy and Critical Thinking: Primary Students Solving Local Environmental Problems through Outdoor Learning

    Science.gov (United States)

    Ampuero, David; Miranda, Christian E.; Delgado, Luisa E.; Goyen, Samantha; Weaver, Sean

    2015-01-01

    The present study explores the outcomes of teaching empathy and critical thinking to solve environmental problems. This investigation was done throughout the duration of an environmental education course within a primary school located in central Chile. A community-based research methodology was used to understand the formation of empathy and…

  3. Empathy and Critical Thinking: Primary Students Solving Local Environmental Problems through Outdoor Learning

    Science.gov (United States)

    Ampuero, David; Miranda, Christian E.; Delgado, Luisa E.; Goyen, Samantha; Weaver, Sean

    2015-01-01

    The present study explores the outcomes of teaching empathy and critical thinking to solve environmental problems. This investigation was done throughout the duration of an environmental education course within a primary school located in central Chile. A community-based research methodology was used to understand the formation of empathy and…

  4. Anticonvulsant pharmacotherapy for generalized and localized vulvodynia : a critical review of the literature

    NARCIS (Netherlands)

    Spoelstra, Symen K.; Borg, Charmaine; Schultz, Willibrord C. M. Weijmar

    2013-01-01

    Anticonvulsant therapy has occasionally been recommended to treat vulvodynia. However, convincing evidence to support this therapeutic option is lacking. The goal of this study was to critically review studies published on the effectiveness of anticonvulsants for the treatment of vulvodynia. Evaluat

  5. Effects of grain size and grain boundary on critical current density of high T(sub c) superconducting oxides

    Science.gov (United States)

    Zhao, Y.; Zhang, Q. R.; Zhang, H.

    1990-01-01

    By means of adding impurity elements in high T sub c oxides, the effects were studied of grain size and grain boundary on the critical current density of the following systems: YBa2Cu3O(7-y) and Bi-Pr-Sr-Ca-Cu-O. In order to only change the microstructure instead of the superconductivity of the grains in the samples, the impurity elements were added into the systems in terms of the methods like this: (1) substituting Y with the lanthanide except Pr, Ce, and Tb in YBa2Cu3O(7-y) system to finning down grains in the samples, therefore, the effect can be investigated of the grain size on the critical current density of 1:2:3 compounds; (2) mixing the high T sub c oxides with the metal elements, such as Ag, according to the composition of (high T sub c oxide)1-xAgx to metallize the grain boundaries in the samples, studying the effect of the electric conductivity of the grain boundaries on the critical current density; (3) adding SiO2, PbO2, and SnO2 into the high T sub c oxide to form impurity phases in the grain boundaries, trying to find out the effects of the impurity phases or metalloid grain boundaries on the critical current density of the high T sub c superconductors. The experimental results indicate that in the case of of the presence of the metalloid grain boundaries finning down grains fails to enhance the j sub c, but restrains it strongly, the granular high T sub c superconductors with the small size grains coupled weakly is always the low j sub c system.

  6. General approach for the determination of the magneto-angular dependence of the critical current of YBCO coated conductors

    Science.gov (United States)

    Zhang, X.; Zhong, Z.; Ruiz, H. S.; Geng, J.; Coombs, T. A.

    2017-02-01

    The physical understanding and numerical modelling of superconducting devices which exploit the high performance of second generation high temperature superconducting tapes (2G-HTS), is commonly hindered by the lack of accurate functions which allow the consideration of the in-field dependence of the critical current. This is true regardless of the manufacturer of the superconducting tape. In this paper, we present a general approach for determining a unified function I c(B, θ), ultimately capable of describing the magneto-angular dependence of the in-field critical current of commercial 2G-HTS tapes in the Lorentz configuration. Five widely different superconducting tapes, provided by three different manufacturers, have been tested in a liquid nitrogen bath and external magnetic fields of up to 400 mT. The critical current was recorded at 90 different orientations of the magnetic field ranging from θ = 0°, i.e., with B aligned with the crystallographic ab-planes of the YBCO layer, towards ±90°, i.e., with B perpendicular to the wider surfaces of the 2G-HTS tape. The whole set of experimental data has been analysed using a novel multi-objective model capable of predicting a sole function I c(B, θ). This allows an accurate validation of the experimental data regardless of the fabrication differences and widths of the superconducting tapes. It is shown that, in spite of the wide set of differences between the fabrication and composition of the considered tapes, at liquid nitrogen temperature the magneto-angular dependence of the in-field critical current of YBCO-based 2G-HTS tapes, can be described by a universal function I c(f(B), θ), with a power law field dependence dominated by the Kim’s factor B/B 0, and an angular dependence moderated by the electron mass anisotropy ratio of the YBCO layer.

  7. Angular dependence of critical current density and magnetoresistance of sputtered high-T{sub c}-films

    Energy Technology Data Exchange (ETDEWEB)

    Geerkens, A.; Frenck, H.J.; Ewert, S. [Technical Univ. of Cottbus (Germany)] [and others

    1994-12-31

    The angular dependence of the critical current density and the magnetoresistance of high-T{sub c}-films in high and low magnetic fields and for different temperatures were measured to investigate the flux pinning and the superconducting properties. A comparison of the results for the different superconductors shows their increasing dependence on the angle {Theta} between the magnetic field and the c-axis of the film due to the anisotropy of the chosen superconductor. Furthermore the influence of the current direction to the {Theta}-rotation plane is discussed.

  8. Assessing the ability of current climate information to facilitate local climate services for the water sector.

    Science.gov (United States)

    Koutroulis, Aristeidis; Tsanis, Ioannis; Grillakis, Manolis; Jacob, Daniela

    2014-05-01

    In the frame of ECLISE EU FP6 project researchers, in close cooperation with local users of the water sector from the area of Crete, Greece, explored the ability of current climate information to develop and support local climate services water resources management and climate adaption policies. A wealth of climate modeling output ranging from event scale to decadal and centennial experiments, at temporal scales ranging from hourly to monthly, and at spatial scales from very high resolution regional climate models (2 km) to typical GCMs, were used in order to practically assess climate change impacts on water resources. Water resources availability issues analysed and facilitated within the project, focusing on estimates of the future water demands of the island, and comparing with seven "state of the art" CMIP5 simulations within COMBINE framework (under RCPs 2.6, 4.5 and 8.5) to estimate water resources availability, during 21st century. The ability of decadal GCM prediction experiments to reproduce basic hydrometeorological variables like precipitation and temperature for local impact studies, was also examined. Water availability for the whole island at basin scale until 2100 is estimated using the SAC-SMA rainfall-runoff model for a range of different scenarios of projected hydro-climatological regime, demand and supply potential. A robust signal of temperature increase and precipitation decrease is projected for all the pathways. Several messages could be extracted from this provider - user interaction such as the communication of basic concepts and uncertainties, user skepticism and feedback. The main user concern was the coarse spatial scale of climate information and in order to cope with this feedback a special case was framed in collaboration with the project modeling groups for demonstrating a high resolution climate modeling application of an extreme precipitation-flood event over the study area. This effort provided a realistic reproduction of the

  9. Effect of Two Interacting Localized Defects on the Critical Load for Thin Cylindrical Shells Under Axial Compression

    Directory of Open Access Journals (Sweden)

    Abdellatif Khamlichi

    2010-01-01

    Full Text Available Problem statement: Many modern structures are made from thin shells. Design of these elements depends to a large extent on their buckling behavior which is hugely affected by the initial geometric imperfections. Approach: For axially compressed isotropic circular cylindrical shells, axisymmetric localized geometric imperfections were found to reduce severely the buckling strength. Among various axisymmetric shapes of localized defects that were investigated, the entering triangular form was recognized to yield the most adverse case. Since multiple localized defects may be present in the same shell structure and interact, studying their mutual effect on the buckling load is of great importance for shell design. Results: In this study, the effect of two interacting entering triangular localized axisymmetric initial geometric imperfections on shell buckling strength under uniform axial compression was modeled by means of the finite element method. A special software package which was dedicated to buckling analysis of quasi axisymmetric shells was used in order to compute the buckling load either via the linear Euler buckling analysis or through the full non linear iterative procedure. A set of five factors including shell aspect ratios, defect characteristics and the distance separating the localized initial geometric imperfections had been found to govern the buckling problem. A statistical approach based on the Taguchi method was used then to study their relative influence on the buckling load reduction. It was shown by comparison with the single imperfection case that further diminution of the critical load was obtained. Conclusion/Recommendations: In the range of investigated parameters, the distance separating the localized geometric imperfections and imperfection wavelength were found to yield major influences on the critical load. Further studies must be performed in order to assess shell buckling strength in the presence of more than two

  10. The local projection in the density functional theory plus U approach: A critical assessment.

    Science.gov (United States)

    Wang, Yue-Chao; Chen, Ze-Hua; Jiang, Hong

    2016-04-14

    Density-functional theory plus the Hubbard U correction (DFT + U) method is widely used in first-principles studies of strongly correlated systems, as it can give qualitatively (and sometimes, semi-quantitatively) correct description of energetic and structural properties of many strongly correlated systems with similar computational cost as local density approximation or generalized gradient approximation. On the other hand, the DFT + U approach is limited both theoretically and practically in several important aspects. In particular, the results of DFT + U often depend on the choice of local orbitals (the local projection) defining the subspace in which the Hubbard U correction is applied. In this work we have systematically investigated the issue of the local projection by considering typical transition metal oxides, β-MnO2 and MnO, and comparing the results obtained from different implementations of DFT + U. We found that the choice of the local projection has significant effects on the DFT + U results, which are more significant for systems with stronger covalent bonding (e.g., MnO2) than those with more ionic bonding (e.g., MnO). These findings can help to clarify some confusion arising from the practical use of DFT + U and may also provide insights for the development of new first-principles approaches beyond DFT + U.

  11. CRITICAL SUCCESS FACTORS FOR BUSINESS – IT ALIGNMENT:A REVIEW OF CURRENT RESEARCH

    OpenAIRE

    Ilir Kurti; Ezmolda Barolli; Kozeta Sevrani

    2013-01-01

    Business-IT alignment still remains one of the three main research streams in IS literature, and from 1994 it constantly ranks among the top three concerns of CIOs. While a lot of research has been published around business-IT alignment in the last three decades, a number of models have been proposed to structure the concept into various dimensions and levels. However, only a few studies have been made regarding the critical success factors. Moreover, we were unable to find any systematically...

  12. CRITICAL SUCCESS FACTORS FOR BUSINESS – IT ALIGNMENT:A REVIEW OF CURRENT RESEARCH

    OpenAIRE

    Ilir Kurti; Ezmolda Barolli; Kozeta Sevrani

    2013-01-01

    Business-IT alignment still remains one of the three main research streams in IS literature, and from 1994 it constantly ranks among the top three concerns of CIOs. While a lot of research has been published around business-IT alignment in the last three decades, a number of models have been proposed to structure the concept into various dimensions and levels. However, only a few studies have been made regarding the critical success factors. Moreover, we were unable to find any systematically...

  13. Current research on cigarette toxicity: critical appraisal in view of clinical laboratory

    Directory of Open Access Journals (Sweden)

    Prajwal Gyawali

    2016-06-01

    Full Text Available Cigarette smoking has been implicated as a potential risk factor for development and progression of chronic obstructive pulmonary disease (COPD and cardiovascular disease (CVD, including ischemic heart disease. Although, several methods are in existence to measuring cigarette toxicity, evidence regarding adoption of a gold standard technique is still imprecise. In this study, we reviewed articles describing methods of measuring cigarette toxicity in relation to clinical laboratory practice. A critical analysis of the benefits and limitations of each method in relation to low-middle income countries is discussed. [Int J Res Med Sci 2016; 4(6.000: 1785-1793

  14. HISTORICAL CRITICAL PEDAGOGY AND OBJECTIVE KNOWLEDGE VERSUS THE MULTICULTURALISM AND RELATIVISM CURRENT ACADEMIC DEBATE

    Directory of Open Access Journals (Sweden)

    Julia Malanchen

    2015-06-01

    Full Text Available The article discusses the existing antagonistic understanding among the authors who discuss curriculum from the multiculturalist perspective and the authors of the Historical-Critical Pedagogy. The aim is to explain the postmodern relativists bases and multiculturalism, which opposes the defense of objective knowledge as central to the organization of a curriculum. Finally we point out what content should integrate an academic, with the objective, human development, human emancipation and social transformation, which allow the human being aim to provide social and consciously so increasingly free and universal.

  15. Superconducting-magnetic heterostructures: a method of decreasing AC losses and improving critical current density in multifilamentary conductors.

    Science.gov (United States)

    Glowacki, B A; Majoros, M

    2009-06-24

    Magnetic materials can help to improve the performance of practical superconductors on the macroscale/microscale as magnetic diverters and also on the nanoscale as effective pinning centres. It has been established by numerical modelling that magnetic shielding of the filaments reduces AC losses in self-field conditions due to decoupling of the filaments and, at the same time, it increases the critical current of the composite. This effect is especially beneficial for coated conductors, in which the anisotropic properties of the superconductor are amplified by the conductor architecture. However, ferromagnetic coatings are often chemically incompatible with YBa(2)Cu(3)O(7) and (Pb,Bi)(2)Sr(2)Ca(2)Cu(3)O(9) conductors, and buffer layers have to be used. In contrast, in MgB(2) conductors an iron matrix may remain in direct contact with the superconducting core. The application of superconducting-magnetic heterostructures requires consideration of the thermal and electromagnetic stability of the superconducting materials used. On one hand, magnetic materials reduce the critical current gradient across the individual filaments but, on the other hand, they often reduce the thermal conductivity between the superconducting core and the cryogen, which may cause destruction of the conductor in the event of thermal instability. A possible nanoscale method of improving the critical current density of superconducting conductors is the introduction of sub-micron magnetic pinning centres. However, the volumetric density and chemical compatibility of magnetic inclusions has to be controlled to avoid suppression of the superconducting properties.

  16. A critical friend: monitoring and evaluation systems, development cooperation and local government. The case of Tuscany.

    Science.gov (United States)

    Rossignoli, Serena; Coticchia, Fabrizio; Mezzasalma, Annarosa

    2015-06-01

    The role of monitoring and evaluation (M&E) systems in the field of development cooperation has globally increased in last decades. International and regional organizations, as well as states, local governments and NGOs have largely adopted the tools provided by M&E in order to enhance transparency, effectiveness and efficiency. The paper aims at verifying how and to what extent the implementation of M&E systems has affected the overall quality of international cooperation projects financed by a local government. After a literature review on M&E in development cooperation, the research analyzes the wide range of activities (evaluation ex-ante, mid-term, final, monitoring, consultancy) carried out by the Evaluation Team of the XY in the last eight years in behalf of an Italian local government: the Region of Tuscany. The paper reveals the strategic significance of adopting M&E systems in the medium-long term.

  17. Influence of Electrolyte Modulus on the Local Current Density at a Dendrite Tip on a Lithium Metal Electrode

    Energy Technology Data Exchange (ETDEWEB)

    Harry, KJ; Higa, K; Srinivasan, V; Balsara, NP

    2016-08-10

    Understanding and controlling the electrochemical deposition of lithium is imperative for the safe use of rechargeable batteries with a lithium metal anode. Solid block copolymer electrolyte membranes are known to enhance the stability of lithium metal anodes by mechanically suppressing the formation of lithium protrusions during battery charging. Time-resolved hard X-ray microtomography was used to monitor the internal structure of a symmetric lithium-polymer cell during galvanostatic polarization. The microtomography images were used to determine the local rate of lithium deposition, i.e. local current density, in the vicinity of a lithium globule growing through the electrolyte. Measurements of electrolyte displacement enabled estimation of local stresses in the electrolyte. At early times, the current density was maximized at the globule tip, as expected from simple current distribution arguments. At later times, the current density was maximized at the globule perimeter. We show that this phenomenon is related to the local stress fields that arise as the electrolyte is deformed. The local current density, normalized for the radius of curvature, decreases with increasing compressive stresses at the lithium-polymer interface. To our knowledge, our study provides the first direct measurement showing the influence of local mechanical stresses on the deposition kinetics at lithium metal electrodes.

  18. Mars ISRU for Production of Mission Critical Consumables - Options, Recent Studies, and Current State of the Art

    Science.gov (United States)

    Sanders, G. B.; Paz, A.; Oryshchyn, L.; Araghi, K.; Muscatello, A.; Linne, D.; Kleinhenz, J.; Peters, T.

    2015-01-01

    In 1978, a ground breaking paper titled, "Feasibility of Rocket Propellant Production on Mars" by Ash, Dowler, and Varsi discussed how ascent propellants could be manufactured on the Mars surface from carbon dioxide collected from the atmosphere to reduce launch mass. Since then, the concept of making mission critical consumables such as propellants, fuel cell reactants, and life support consumables from local resources, commonly known as In-Situ Resource Utilization (ISRU), for robotic and human missions to Mars has been studied many times. In the late 1990's, NASA initiated a series of Mars Human Design Reference Missions (DRMs), the first of which was released in 1997. These studies primarily focused on evaluating the impact of making propellants on Mars for crew ascent to Mars orbit, but creating large caches of life support consumables (water & oxygen) as a backup for regenerative life support systems for long-duration surface stays (>500 days) was also considered in Mars DRM 3.0. Until science data from the Mars Odyssey orbiter and subsequent robotic missions revealed that water may be widely accessable across the surface of Mars, prior Mars ISRU studies were limited to processing Mars atmospheric resources (carbon dioxide, nitrogen, argon, oxygen, and water vapor). In December 2007, NASA completed the Mars Human Design Reference Architecture (DRA) 5.0 study which considered water on Mars as a potential resource for the first time in a human mission architecture. While knowledge of both water resources on Mars and the hardware required to excavate and extract the water were very preliminary, the study concluded that a significant reduction in mass and significant enhancements to the mission architecture were possible if Mars water resources were utilized. Two subsequent Mars ISRU studies aimed at reexamining ISRU technologies, processing options, and advancements in the state-of-the-art since 2007 and to better understand the volume and packaging associated

  19. Critical appraisal of the current practice in murine TNBS-induced colitis

    NARCIS (Netherlands)

    A.A.T. Velde; M.I. Verstege; D.W. Hommes

    2006-01-01

    There is no standard practice in the induction of colitis by 2,4,6-trinitrobenzene sulfonic acid. In this review the current practice in 2,4,6-trinitrobenzene sulfonic acid colitis is studied using 20 recently published articles. We compare the different protocols, discuss the mechanism of disease a

  20. Critical analysis of the current treatment guidelines for complex ptsd in adults

    NARCIS (Netherlands)

    de Jongh, A.; Resick, P.A.; Zoelner, L.A.; van Minnen, A.; Lee, C.W.; Monson, C.M.; Foa, E.B.; Wheeler, K.; ten Broeke, E.; Feeny, N.; Rauch, S.A.M.; Chard, K.M.; Mueser, K.T.; Sloan, D.M.; van der Gaag, M.; Rothbaum, B.O.; Neuner, F.; de Roos, C.; Hehenkamp, L.M.J.; Rosner, R.; Bicanic, I.A.E.

    2016-01-01

    According to current treatment guidelines for Complex PTSD (cPTSD), psychotherapy for adults with cPTSD should start with a “stabilization phase.” This phase, focusing on teaching self-regulation strategies, was designed to ensure that an individual would be better able to tolerate trauma-focused

  1. CRITICAL ANALYSIS of the CURRENT TREATMENT GUIDELINES for COMPLEX PTSD in ADULTS

    NARCIS (Netherlands)

    De Jongh, Ad; Resick, Patricia A.; Zoellner, Lori A.; Van Minnen, Agnes; Lee, Christopher W.; Monson, Candice M.; Foa, Edna B.; Wheeler, Kathleen; Broeke, Erik Ten; Feeny, Norah; Rauch, Sheila A M; Chard, Kathleen M.; Mueser, Kim T.; Sloan, Denise M.; Van Der Gaag, Mark; Rothbaum, Barbara Olasov; Neuner, Frank; De Roos, Carlijn; Hehenkamp, Lieve M J; Rosner, Rita; Bicanic, Iva A E

    2016-01-01

    According to current treatment guidelines for Complex PTSD (cPTSD), psychotherapy for adults with cPTSD should start with a "stabilization phase." This phase, focusing on teaching self-regulation strategies, was designed to ensure that an individual would be better able to tolerate trauma-focused

  2. Current research trends and perspectives on materials-based hydrogen storage solutions: A critical review

    CSIR Research Space (South Africa)

    Ren, Jianwei

    2016-01-01

    Full Text Available Effective hydrogen storage solutions have been pursued for decades, and materials-based hydrogen storage is a research frontier of much current interest. Yet, no researched materials to date have come close to the DOE 2020 targets for hydrogen...

  3. Ghost spins and quantum critical behavior in a spin chain with local bond deformation

    Science.gov (United States)

    Dai, Jianhui; Wang, Yupeng; Eckern, U.

    1999-09-01

    We study the impurity-induced critical behavior in an integrable SU(2)-invariant model consisting of an open spin chain of arbitrary spin S (Takhatajian-Babujian model) interacting with an impurity of spin S-->' located at one of the boundaries. For S=1/2 or S'=1/2, the impurity interaction takes a very simple form JS-->1.S-->' that describes the deformed boundary bond between the impurity S-->' and the first bulk spin S-->1 with an arbitrary coupling strength J. For a weak coupling 0S, and S'=J0/[(S+S')2-1/4], the impurity spin is split into two ghost spins. Their cooperative effect leads to a variety of new critical behaviors with different values of \\|S'-S\\|.

  4. A DMFT+CTQMC Investigation of Strange Metallicity in Local Quantum Critical Scenario

    Science.gov (United States)

    Acharya, Swagata; Laad, M. S.; Taraphder, A.

    2016-10-01

    “Strange” metallicity is now a pseudonym for a novel metallic state exhibiting anomalous infra-red (branch-cut) continuum features in one- and two-particle responses. Here, we employ dynamical mean-field theory (DMFT) using low-temperature continuous-time- quantum Monte-Carlo (CTQMC) solver for an extended periodic Anderson model (EPAM) model to investigate unusual magnetic fluctuations in the strange metal. We show how extinction of Landau quasiparticles in the orbital selective Mott phase (OSMP) leads to (i) qualitative explication of strange transport features and (ii) anomalous quantum critical magnetic fluctuations due to critical liquid-like features in dynamical spin fluctuations, in excellent accord with data in some f-electron systems.

  5. Radio-guided localization of clinically occult breast lesions: current modalities and future directions.

    Science.gov (United States)

    Aydogan, Fatih; Velidedeoglu, Mehmet; Kilic, Fahrettin; Yilmaz, Halit

    2014-01-01

    The extensive availability of breast cancer screening programs and improvement in diagnostic imaging have led to more frequent detection of suspicious and clinically occult breast lesions. Early detection of tumor is important for breast-conserving treatment. Incomplete excision is a major risk factor for local recurrence. Following precise localization and removing the entire lesion while achieving adequate clear margins is the key factor for successful management of non-palpable breast lesions. For this purpose, several techniques such as wire-guided localization, intra-operative ultrasound guided resection, radio-guided occult lesion localization and radioactive seed localization have been described and applied. In this article, we overview the two commonly used localization techniques, radio-guided occult lesion localization and wire-guided localization, particularly describing their advantages and drawbacks.

  6. Critical analysis of the empirical tests of local hidden-variable theories

    Science.gov (United States)

    Santos, Emilio

    1992-10-01

    A local hidden-variable model is exhibited for the experiments by Aspect, Grangier, and Roger [Phys. Rev. Lett. 47, 460 (1981); 49, 91 (1982)] and Aspect, Dalibard, and Roger [Phys. Rev. Lett. 49, 1804 (1982)] measuring polarization correlation of optical-photon pairs. The model agrees with quantum-mechanical predictions for all measurable quantities even with ideal polarizers and detectors, and emphasizes the need of a high degree of directional correlation, besides the correlation of spin (or polarization or other quantities), in any test of locality. It is proved that homogeneous inequalities, involving only coincidence detection rates, cannot discriminate between quantum mechanics and local theories, which invalidates all previously used empirical tests. The role of supplementary assumptions, like the so-called no enhancement, for the derivation of Bell's inequalities is discussed. Finally it is conjectured that quantum mechanics might be compatible with local realism, if we assume that not all self-adjoint operators represent observables and not all density operators represent states.

  7. Biological Activities and Bioavailability of Mangosteen Xanthones: A Critical Review of the Current Evidence

    Directory of Open Access Journals (Sweden)

    Mark L. Failla

    2013-08-01

    Full Text Available Mangosteen (Garcinia mangostana L. is a tropical tree native to Southeast Asia that produces a fruit whose pericarp contains a family of tricyclic isoprenylated polyphenols referred to as xanthones. Numerous in vitro studies have shown that these xanthones possess anti-oxidant, anti-proliferative, pro-apoptotic, anti-inflammatory and anti-carcinogenic activities. Aggressive marketing of such health promoting benefits has resulted in mangosteen’s classification as a “superfruit”. This has led to sales of mangosteen containing beverages in USA alone exceeding $200 million in 2008 despite very limited animal and human studies. This review will (a critically address recent reports of in vivo studies on the bioavailability and metabolism of mangosteen xanthones, (b update the in vitro and in vivo data on anti-cancer and anti-inflammatory activities of mangosteen xanthones, and (c suggest needed areas of inquiry regarding the absorption, metabolism and efficacy of mangosteen xanthones.

  8. Do current clinical trials meet society's needs?: a critical review of recent evidence.

    Science.gov (United States)

    Pocock, Stuart J; Gersh, Bernard J

    2014-10-14

    This paper describes some important controversies regarding the current state of clinical trials research in cardiology. Topics covered include the inadequacy of trial research on medical devices, problems with industry-sponsored trials, the lack of head-to-head trials of new effective treatments, the need for wiser handling of drug safety issues, the credibility (or lack thereof) of trial reports in medical journals, problems with globalization of trials, the role of personalized (stratified) medicine in trials, the need for new trials of old drugs, the need for trials of treatment withdrawal, the importance of pragmatic trials of treatment strategies, and the limitations of observational comparative effectiveness studies. All issues are illustrated by recent topical trials in cardiology. Overall, we explore the extent to which clinical trials, as currently practiced, are successful in meeting society's expectations.

  9. Critical review of geometry in current textbooks in lower secondary schools in Japan and the UK

    OpenAIRE

    Fujita, T; Jones, K

    2003-01-01

    This paper reports on an initial analysis of current best-selling textbooks for lower secondary schools in Japan and the UK (specifically Scotland) using an analytic framework derived from the study of the textbooks in the “Trends in International Mathematics and Science Study” (TIMSS). Our analysis indicates that, following the specification of the mathematics curriculum in these countries, Japanese textbooks set out to develop students’ deductive reasoning skills through the explicit teachi...

  10. Language Ideologies and Local Languages as the Medium-of-Instruction Policy: A Critical Ethnography of a Multilingual School in Nepal

    Science.gov (United States)

    Phyak, Prem

    2013-01-01

    This paper analyzes the ideologies and practices of local languages as the medium-of-instruction (MOI) policy in a multilingual school in Nepal. Grounded on the notion of language policy as a locally situated social practice, this critical ethnographic study investigates challenges--both ideological and implementational--that local languages MOI…

  11. Current technological advances in magnetic resonance with critical impact for clinical diagnosis and therapy.

    Science.gov (United States)

    Runge, Val M

    2013-12-01

    The last 5 years of technological advances with major impact on clinical magnetic resonance (MR) are discussed, with greater emphasis on those that are most recent. These developments have already had a critical positive effect on clinical diagnosis and therapy and presage continued rapid improvements for the next 5 years. This review begins with a discussion of 2 topics that encompass the breadth of MR, in terms of anatomic applications, contrast media, and MR angiography. Subsequently, innovations are discussed by anatomic category, picking the areas with the greatest development, starting with the brain, moving forward to the liver and kidney, and concluding with the musculoskeletal system, breast, and prostate. Two final topics are then considered, which will likely, with time, become independent major fields in their own right, interventional MR and MR positron emission tomography (PET).The next decade will bring a new generation of MR contrast media, with research focused on substantial improvements (>100-fold) in relaxivity (contrast effect), thus providing greater efficacy, safety, and tissue targeting. Magnetic resonance angiography will see major advances because of the use of compressed sensing, in terms of spatial and temporal resolution, with movement away from nondynamic imaging. The breadth of available techniques and tissue contrast has greatly expanded in brain imaging, benefiting both from the introduction of new basic categories of imaging techniques, such as readout-segmented echo planar imaging and 3D fast spin echo imaging with variable flip angles, and from new refinements specific to anatomic areas, such as double inversion recovery and MP2RAGE. Liver imaging has benefited from the development of techniques to easily and rapidly assess lipid, and will see, overall, a marked improvement in the next 5 years from new techniques on the verge of clinical introduction, such as controlled aliasing in parallel imaging results in higher acceleration

  12. Rank aggregation of local expert knowledge for conservation planning of the critically endangered saola.

    Science.gov (United States)

    Wilkinson, Nicholas M; Van Duc, Luong

    2017-06-01

    There has been much recent interest in using local knowledge and expert opinion for conservation planning, particularly for hard-to-detect species. Although it is possible to ask for direct estimation of quantities such as population size, relative abundance is easier to estimate. However, an expert's knowledge is often geographically restricted relative to the area of interest. Combining (or aggregating) experts' assessments of relative abundance is difficult when each expert only knows a part of the area of interest. We used Google's PageRank algorithm to aggregate ranked abundance scores elicited from local experts through a rapid rural-appraisal method. We applied this technique to conservation planning for the saola (Pseudoryx nghetinhensis), a poorly known bovid. Near a priority landscape for the species, composed of 3 contiguous protected areas, we asked groups of local people to indicate relative abundances of saola and other species by placing beans on community maps. For each village, we used this information to rank areas within the knowledge area of that village for saola abundance. We used simulations to compare alternative methods to aggregate the rankings from the different villages. The best-performing method was then used to produce a single map of relative abundance across the entire landscape, an area larger than that known to any one village. This map has informed prioritization of surveys and conservation action in the continued absence of direct information about the saola. © 2016 Society for Conservation Biology.

  13. Locally self-organized quasi-critical percolation in a multiple disease model

    CERN Document Server

    Juul, Jeppe

    2011-01-01

    Diseases emerge, persist and vanish in an ongoing battle for available hosts. Hosts, on the other hand, defend themselves by developing immunity that limits the ability of pathogens to reinfect them. We here explore a multi-disease system with emphasis on mutual exclusion. We demonstrate that such a system develops towards a steady state, where the spread of individual diseases self-organizes to a state close to that of critical percolation, without any global control mechanism or separation of time scale. For a broad range of introduction rates of new diseases, the likelihood of transmitting diseases remains approximately constant.

  14. Recanalization of Chronic Total Occlusion Lesions: A Critical Appraisal of Current Devices and Techniques

    Science.gov (United States)

    2016-01-01

    Chronic Total Occlusion (CTO) has been considered as one of the “final frontier” in interventional cardiology. Until recently, the patients with CTO are often managed surgically or medically due to lack of published evidence of clinical benefits and lower success rate of percutaneous recanalization of CTO. However, the introduction of enhanced guidewires, microcatheters combined with novel specialized devices and techniques reduce the number of unapproachable CTO. In this review article, current techniques and devices of percutaneous recanalization of CTO have been systematically summarized, which may help budding interventional cardiologists to theoretically understand these complex procedures and to deliver safe and effective percutaneous management of CTO to the patients. PMID:27790503

  15. Constructivisms from a genetic point of view: a critical classification of current tendencies.

    Science.gov (United States)

    Sánchez, José Carlos; Loredo, José Carlos

    2009-12-01

    In this paper, we propose a critical classification of contemporary constructivist orientations. Our fundamental theoretical reference is the notion of genesis, understood as the construction of reality in a way that is neither relativist nor positivist-realist. We identify a nucleus of classic, genetic constructivism that revolves around the ideas of Baldwin, Piaget and Vygotsky and discuss two tendencies that distort the spirit of that nucleus: objectivism and subjectivism. Objectivism rules out the psychological, constructive activity of the subject, subordinating (or just reducing) it to objective structures either from nature (like genetic endowment or neural functioning), or from culture (like language or social practices). Subjectivism completely detaches the objectivity of knowledge from its construction on the part of the subject, reducing it to the mere product of individual interest, view, or irrationality. Thus, subjectivism is the non-constructive way to conceive the subject. Then, we attempt to show the dialectics that exists between these two tendencies and the scope of our criteria by analysing a representative (non exhaustive) group of authors who are defined as constructivists or who bring important elements to the debate about constructivism.

  16. A critical overview of the current myofascial pain literature - January 2016.

    Science.gov (United States)

    Dommerholt, Jan; Finnegan, Michelle; Grieve, Rob; Hooks, Todd

    2016-01-01

    Reflecting on the past year, the number of publications on myofascial pain continues to increase in a steady rate. The current review includes 30 basic and clinical studies, case reports, reviews, and reports from fifteen different countries about trigger points (TrP), myofascial pain (MP), dry needling (DN) and other related interventions. We are pleased that during 2015 this article made the top 15 of most downloaded articles as many as three times! In general, the quality of published papers is improving as well. Nevertheless, several papers included in this overview, mention the application of "ischemic compression", which is a questionable concept in the context of TrP inactivation. As we have outlined previously, in the current thinking about myofascial pain, TrPs feature significant hypoxia and a lowered pH (Ballyns et al., 2011; Shah and Gilliams, 2008), and attempts to induce more ischemia would be counterproductive. Already in 1999, Simons, Travell and Simons changed the terminology from ischemic compression to TrP compression (Simons et al., 1999) and we recommend that contemporary researchers and clinicians adopt the new terminology and stop using the term "ischemic compression."

  17. Phase Diagrams, Criticality, and Local Properties of Spin Glasses and Random-Field Ising Models from Renormalization - Calculations.

    Science.gov (United States)

    Hartford, Edward John

    This position-space renormalization-group study focuses on two systems with quenched disorder: the Ising spin glass and the asymmetric random-field Ising model. We have employed the Migdal-Kadanoff approach to determine local recursion relations and have retained the full correlated probability distribution of interactions and fields at each iteration in a series of histograms. We find an equilibrium spin-glass phase in three dimensions, but not in two. The spin glass is characterized by a distribution of effective interactions that broadens under iteration, signaling both the long-range order of the phase and the importance of competing interactions on all length scales. We have introduced a method to calculate the distribution of local properties by differentiating the free energy with respect to a particular magnetic field or interaction. Within the spin-glass phase, the nearest neighbor correlation ranges from negative one to one, showing the strong correlations and the local variation within the phase. The spin-glass-to-paramagnet phase transition is second order, with a smooth specific heat indicated by a negative critical exponent alpha. The multicritical point separating the spin-glass, paramagnetic, and ferromagnetic phases lies along the Nishimori line and also has a nondivergent specific heat. When the system undergoes quenched dilution, the resulting critical and multicritical behaviors are identical to those of the undiluted system. Even the addition of an infinitesimal magnetic field destroys the long-range spin-glass order; however, the characteristic broadening of the distribution continues for several iterations for small fields and low temperatures, suggesting the persistence of sizable spin-glass domains. Our study of the asymmetric random-field Ising model is motivated by recent experiments on phase transitions in porous media and mean-field treatments, which suggest that new critical behavior could occur when the distribution of fields is

  18. Application of Hazard Analysis Critical Control Point in the local manufacture of ready-to-use therapeutic foods (RUTFs).

    Science.gov (United States)

    Henry, C Jeya K; Xin, Janice Lim Wen

    2014-06-01

    The local manufacture of ready-to-use therapeutic foods (RUTFs) is increasing, and there is a need to develop methods to ensure their safe production. We propose the application of Hazard Analysis Critical Control Point (HACCP) principles to achieve this goal. The basic principles of HACCP in the production of RUTFs are outlined. It is concluded that the implementation of an HACCP system in the manufacture of RUTFs is not only feasible but also attainable. The introduction of good manufacturing practices, coupled with an effective HACCP system, will ensure that RUTFs are produced in a cost-effective, safe, and hygienic manner.

  19. High critical current density in powder-in-tube processed MgB2/Ta/Cu wire

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The magnetization of dense MgB2/Ta/Cu wires prepared by the powder-in-tube method is measured by a SQUID magnetometer. The results indicate that the critical temperature of MgB2/Ta/Cu is around 38.4 K with a sharp transition width of 0.6 K. The MgB2/Ta/Cu wire shows a strong flux pinning and the critical current density is higher than 105 A/cm2 (5 K, self-field) and 104 A/cm2 (20 K, 1 T). Also, the irreversibility field of the sample reaches 6.6 T at 5 K.

  20. A Critical Assessment of the Resource Depletion Potential of Current and Future Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Jens F. Peters

    2016-12-01

    Full Text Available Resource depletion aspects are repeatedly used as an argument for a shift towards new battery technologies. However, whether serious shortages due to the increased demand for traction and stationary batteries can actually be expected is subject to an ongoing discussion. In order to identify the principal drivers of resource depletion for battery production, we assess different lithium-ion battery types and a new lithium-free battery technology (sodium-ion under this aspect, applying different assessment methodologies. The findings show that very different results are obtained with existing impact assessment methodologies, which hinders clear interpretation. While cobalt, nickel and copper can generally be considered as critical metals, the magnitude of their depletion impacts in comparison with that of other battery materials like lithium, aluminum or manganese differs substantially. A high importance is also found for indirect resource depletion effects caused by the co-extraction of metals from mixed ores. Remarkably, the resource depletion potential per kg of produced battery is driven only partially by the electrode materials and thus depends comparably little on the battery chemistry itself. One of the key drivers for resource depletion seems to be the metals (and co-products in electronic parts required for the battery management system, a component rather independent from the actual battery chemistry. However, when assessing the batteries on a capacity basis (per kWh storage capacity, a high-energy density also turns out to be relevant, since it reduces the mass of battery required for providing one kWh, and thus the associated resource depletion impacts.

  1. Liquid Metallic Hydrogen II. A Critical Assessment of Current and Primordial Helium Levels in the Sun

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2013-04-01

    Full Text Available Before a solar model becomes viable in astrophysics, one mus t consider how the ele- mental constitution of the Sun was ascertained, especially relative to its principle com- ponents: hydrogen and helium. Liquid metallic hydrogen has been proposed as a solar structural material for models based on condensed matter (e .g. Robitaille P.-M. Liq- uid Metallic Hydrogen: A Building Block for the Liquid Sun. Progr. Phys. , 2011, v. 3, 60–74. There can be little doubt that hydrogen plays a d ominant role in the uni- verse and in the stars; the massive abundance of hydrogen in t he Sun was established long ago. Today, it can be demonstrated that the near isointe nse nature of the Sun’s Balmer lines provides strong confirmatory evidence for a dis tinct solar surface. The situation relative to helium remains less conclusive. Stil l, helium occupies a prominent role in astronomy, both as an element associated with cosmol ogy and as a byproduct of nuclear energy generation, though its abundances within the Sun cannot be reliably estimated using theoretical approaches. With respect to th e determination of helium lev- els, the element remains spectroscopically silent at the le vel of the photosphere. While helium can be monitored with ease in the chromosphere and the prominences of the corona using spectroscopic methods, these measures are hig hly variable and responsive to elevated solar activity and nuclear fragmentation. Dire ct assays of the solar winds are currently viewed as incapable of providing definitive in formation regarding solar helium abundances. As a result, insight relative to helium r emains strictly based on the- oretical estimates which couple helioseismological appro aches to metrics derived from solar models. Despite their “state of the art” nature, heliu m estimates based on solar models and helioseismology are suspect on several fronts, i ncluding their reliance on solar opacities. The best knowledge can only come from the so

  2. Scaling and Locality properties of the Entanglement Hamiltonian in Critical Fermionic systems

    Science.gov (United States)

    Lanata, Nicola; Yao, Yong-Xin; Deng, Xiaoyu; Pouranvari, Mohammad

    We study the entanglement Hamiltonian of several gapless Fermionic systems. In particular, we consider an infinite metallic one dimensional chain of free Fermions, and show that the corresponding entanglement Hamiltonian F (L) for a subsystem of length L is local. Furthermore, we show that F (L) displays a well defined continuum limit, which is related with the so called logarithmically enhanced area law of the entanglement entropy, S (L) ~ log (L) . Finally, using the ``Gutzwiller renormalization group'' [arXiv:1509.05441], we discuss these concepts in relation with the physics of the Anderson impurity model.

  3. Structural and critical current properties in polycrystalline SmFeAsO{sub 1-x}F{sub x}

    Energy Technology Data Exchange (ETDEWEB)

    Wang Lei; Gao Zhaoshun; Qi Yanpeng; Zhang Xianping; Wang Dongliang; Ma Yanwei [Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, PO Box 2703, Beijing 100190 (China)], E-mail: ywma@mail.iee.ac.cn

    2009-01-15

    A series of polycrystalline SmFeAsO{sub 1-x}F{sub x} bulks (x = 0.15, 0.2, 0.3 and 0.4) was prepared by a conventional solid state reaction. The resistivity, susceptibility, magnetic hysteresis, critical current density, and microstructure of these samples have been investigated. The resistivity result shows that the critical transition temperature T{sub c} increases steadily with increasing fluorine content, with the highest onset T{sub c} = 53 K at x = 0.4. On the other hand, a study on the effect of lattice constants on the critical transition temperature and resistivity at 60 K ({rho}{sub 60K}) presents a possible correlation; that is, T{sub c} increases with the shrinkage of the a-axis while {rho}{sub 60 K} increases with the enlargement of the c-axis. A global critical current density of 1.1 x 10{sup 4} A cm{sup -2} at 5 K in self-field was achieved in the purest sample. An inter-grain J{sub c} of about 3.6 x 10{sup 3} A cm{sup -2} at 5 K in self-field was estimated by comparing the difference in magnetization between powder and bulk samples, in contrast to the intra-grain J{sub c} of 10{sup 6} A cm{sup -2}. A weak field dependence was observed in the estimated inter-grain J{sub c}, and the effect of composition gradients on the inter-grain J{sub c} is discussed.

  4. [Disabled people in current economically critical situation. Statistics, legislation and institutions, role of occupational physician].

    Science.gov (United States)

    Leocata, G

    2012-01-01

    The number of employed disabled people decreased in 2008-2009 while there has been an increase in the number of temporary contracts and employed disabled women. The work admission of foreign disabled workers has decreased whereas admission of people with psychic problems has been positively assessed. The ASL (Local Health Service) occupational physicians face some difficulties in the Civil Disability Boards for the excessive number of patients and because of the conflict between their inspective role in institutional activity and their task of checking working conditions of disabled workers. Often company physicians do not follow disabled people from recruitment or when not subjected to health surveillance. In addition they face difficulties when companies intend to fire a disabled person or ask for unsuitable work performances. Generally speaking, specialists working in INAIL (Italian Workers' Compensation Authority) are not adequately integrated with subjects/agencies/organizations working in the specific sector of targeted employment and their forensic physicians are not allowed to monitor disabled people conditions within the company.

  5. Urethral Stricture is an Unpleasant Complication after Prostate Surgery: A Critical Review of Current Literature

    Directory of Open Access Journals (Sweden)

    Emrullah Söğütdelen

    2016-03-01

    Full Text Available Urethral stricture is narrowing of the urethra due to inflammation that results in scarring. Prostatectomies for benign and malign prostatic diseases are common surgical procedures among men mainly after their fifties. Urethral stricture or bladder neck contraction following transurethral resection of the prostate (TURP is seen in up to 19% of men in different series. Urethral stricture after laser prostatectomy is less frequently reported than TURP, which is about 3.6%. Open prostatectomy for benign prostatic hyperplasia is the oldest technique, nonetheless, it is a reasonable alternative for patients with larger prostates. Urethral stricture is reported in 1.9-4.8% of patients after open prostatectomy. Radical prostatectomy (RP is the most common surgical procedure done worldwide for the treatment of localized prostate cancer. Contracture of the bladder neck at the level of the anastomosis is a well-recognized complication after RP occurring in 0.4-32% of patients. Strictures are mainly treated with endoscopic procedures. Rarely, urethroplasty with buccal mucosa grafts is needed for more complicated cases.

  6. Estimation of critical current distribution in Bi2Sr2CaCu2O x cables and coils using a self-consistent model

    Science.gov (United States)

    Liu, Donghui; Xia, Jing; Yong, Huadong; Zhou, Youhe

    2016-06-01

    Superconducting magnets can generate high magnetic fields. Multi-filamentary Ag-alloy sheathed Bi2Sr2CaCu2O x (Bi-2212) round wire can have a high critical current density in a very high magnetic field. Thus, Bi-2212 has great potential for the development of high-field magnets. For safe and reliable operation of superconducting magnets, it is necessary to estimate the critical current during the design of cables and coils. In this paper, we extend the self-consistent model proposed by Zermeño et al to study the critical current of Bi-2212 cables and coils. First, based on the distribution of Bi-2212 filaments and the experimental test of the critical current of a single strand, the critical currents in cables and coils are calculated. The self-field effect on the critical current is also analyzed. Then, we use an equivalent model to to estimate critical current of large superconducting coils. The equivalent model can effectively estimate the critical current in coils. Using the equivalent model, the results of coils in self-field and high field are compared and discussed. The method and results could be useful for the design of high-field coils.

  7. Distinct doping dependence of critical temperature and critical current density in Ba1-xKxFe2As2 superconductor.

    Science.gov (United States)

    Song, Dongjoon; Ishida, Shigeyuki; Iyo, Akira; Nakajima, Masamichi; Shimoyama, Jun-Ichi; Eisterer, Michael; Eisaki, Hiroshi

    2016-05-25

    Since the high transition temperature (High-Tc) superconductivity was discovered in the series of materials containing iron (Fe), their potential for the applications has been extensively scrutinized. In particular, a lot of effort has been made in achieving the high current-carrying ability by revealing the vortex pinning behavior. Here, we report on the critical current density (Jc) for the pristine Ba1-xKxFe2As2 single crystals with various K concentrations (0.25 ≤ x ≤ 0.52) determined by the magnetization hysteresis loop measurements. The x-dependence of Jc is characterized by a spike-like peak at x ~ 0.30, which corresponds to the under-doped region. This behavior is distinct from a moderate Tc dome with a broad maximum spanning from x ~ 0.3 to 0.5. For the under-doped samples, with increasing magnetic field (H), a second magnetization peak in Jc is observed, whereas for the optimally- and over-doped samples, Jc monotonically decreases with H. This result emphasizes that fine tuning of doping composition is important to obtain strong flux pinning. The origin of the characteristic doping dependence of Jc is discussed in connection with the orthorhombic phase domain boundary, as well as the chemical inhomogeneity introduced by the dopant substitutions.

  8. Distinct doping dependence of critical temperature and critical current density in Ba1‑xKxFe2As2 superconductor

    Science.gov (United States)

    Song, Dongjoon; Ishida, Shigeyuki; Iyo, Akira; Nakajima, Masamichi; Shimoyama, Jun-Ichi; Eisterer, Michael; Eisaki, Hiroshi

    2016-05-01

    Since the high transition temperature (High-Tc) superconductivity was discovered in the series of materials containing iron (Fe), their potential for the applications has been extensively scrutinized. In particular, a lot of effort has been made in achieving the high current-carrying ability by revealing the vortex pinning behavior. Here, we report on the critical current density (Jc) for the pristine Ba1‑xKxFe2As2 single crystals with various K concentrations (0.25 ≤ x ≤ 0.52) determined by the magnetization hysteresis loop measurements. The x-dependence of Jc is characterized by a spike-like peak at x ~ 0.30, which corresponds to the under-doped region. This behavior is distinct from a moderate Tc dome with a broad maximum spanning from x ~ 0.3 to 0.5. For the under-doped samples, with increasing magnetic field (H), a second magnetization peak in Jc is observed, whereas for the optimally- and over-doped samples, Jc monotonically decreases with H. This result emphasizes that fine tuning of doping composition is important to obtain strong flux pinning. The origin of the characteristic doping dependence of Jc is discussed in connection with the orthorhombic phase domain boundary, as well as the chemical inhomogeneity introduced by the dopant substitutions.

  9. High critical current Ag and Ag alloy sheathed multifilament Bi-2223 tapes

    DEFF Research Database (Denmark)

    Wang, W.G.; Han, Z.; Skov-Hansen, P.;

    1999-01-01

    grain connectivity through reducing the 2201 phase and alkaline earth cuprate phases, increasing superconductor core density as well as enhancing current contribution from edge filaments. A high J(c) of 50 kA/cm(2) with an I-c of 42 A has been achieved reproducibly in 19 filament tapes with dimensions...... of 0.16x2.8 mm(2) and silver/superconductor ratios of 4.4:1. By reducing the silver ratio, a J(e) of 14 kA/cm(2) with an I, of 38 A has been obtained in 55 filament tapes and an I-c of 84 A has been obtained in a tape with dimensions of 4x0.23 mm(2). A record J(c) of more than 30 kA/cm(2) with an I...

  10. Cross-validation of component models: a critical look at current methods.

    Science.gov (United States)

    Bro, R; Kjeldahl, K; Smilde, A K; Kiers, H A L

    2008-03-01

    In regression, cross-validation is an effective and popular approach that is used to decide, for example, the number of underlying features, and to estimate the average prediction error. The basic principle of cross-validation is to leave out part of the data, build a model, and then predict the left-out samples. While such an approach can also be envisioned for component models such as principal component analysis (PCA), most current implementations do not comply with the essential requirement that the predictions should be independent of the entity being predicted. Further, these methods have not been properly reviewed in the literature. In this paper, we review the most commonly used generic PCA cross-validation schemes and assess how well they work in various scenarios.

  11. Person-centred health care: a critical assessment of current and emerging research approaches.

    Science.gov (United States)

    Martin, Carmel M; Félix-Bortolotti, Margot

    2014-12-01

    Person-centred health care is prominent in international health care reforms. A shift to understanding and improving personal care at the point of delivery has generated debates about the nature of the person-centred research agenda. This paper purviews research paradigms that influence current person-centred research approaches and traditions that influence knowledge foundations in the field. It presents a synthesis of the emergent approaches and methodologies and highlights gaps between static academic research and the increasing accessibility of evaluation, informatics and big data from health information systems. Paradigms in health services research range from theoretical to atheoretical, including positivist, interpretive, postmodern and pragmatic. Interpretivist (subjective) and positivist (objectivist) paradigms have been historically polarized. Yet, integrative and pragmatic approaches have emerged. Nevertheless, there is a tendency to reductionism, and to reduce personal experiences to metrics in the positivist paradigm. Integrating personalized information into clinical systems is increasingly driven by the pervasive health information technology, which raises many issues about the asymmetry and uncertainty in the flow of information to support personal health journeys. The flux and uncertainty of knowledge between and within paradigmatic or pragmatic approaches highlights the uncertainty and the 'unorder and disorder' in what is known and what it means. Transdisciplinary, complex adaptive systems theory with multi-ontology sense making provides an overarching framework for making sense of the complex dynamics in research progress. A major challenge to current research paradigms is focus on the individualizing of care and enhancing experiences of persons in health settings. There is an urgent need for person-centred research to address this complex process. A transdisciplinary and complex systems approach provides a sense-making framework. © 2014 John

  12. GEP, a Local Growth Factor, is Critical for Odontogenesis and Amelogenesis

    Directory of Open Access Journals (Sweden)

    Zhengguo Cao, Baichun Jiang, Yixia Xie, Chuan-ju Liu, Jian Q. Feng

    2010-01-01

    Full Text Available Granulin epithelin precursor (GEP is a new growth factor that functions in brain development, chondrogenesis, tissue regeneration, tumorigenesis, and inflammation. The goal of this study was to study whether GEP was critical for odontogenesis and amelogenesis both in vivo and in vitro. The in situ hybridization and immunohistochemistry data showed that GEP was expressed in both odontoblast and ameloblast cells postnatally. Knockdown of GEP by crossing U6-ploxPneo-GEP and Sox2-Cre transgenic mice led to a reduction of dentin thickness, an increase in predentin thickness, and a reduction in mineral content in enamel. The in vitro application of recombinant GEP up-regulated molecular markers important for odontogenesis (DMP1, DSPP, and ALP and amelogenesis (ameloblastin, amelogenin and enamelin. In conclusion, both the in vivo and the in vivo data support an important role of GEP in tooth formation during postnatal development.

  13. GEP, a local growth factor, is critical for odontogenesis and amelogenesis.

    Science.gov (United States)

    Cao, Zhengguo; Jiang, Baichun; Xie, Yixia; Liu, Chuan-ju; Feng, Jian Q

    2010-11-25

    Granulin epithelin precursor (GEP) is a new growth factor that functions in brain development, chondrogenesis, tissue regeneration, tumorigenesis, and inflammation. The goal of this study was to study whether GEP was critical for odontogenesis and amelogenesis both in vivo and in vitro. The in situ hybridization and immunohistochemistry data showed that GEP was expressed in both odontoblast and ameloblast cells postnatally. Knockdown of GEP by crossing U6-ploxPneo-GEP and Sox2-Cre transgenic mice led to a reduction of dentin thickness, an increase in predentin thickness, and a reduction in mineral content in enamel. The in vitro application of recombinant GEP up-regulated molecular markers important for odontogenesis (DMP1, DSPP, and ALP) and amelogenesis (ameloblastin, amelogenin and enamelin). In conclusion, both the in vivo and the in vivo data support an important role of GEP in tooth formation during postnatal development.

  14. Anomalous Thouless energy and critical statistics on the metallic side of the many-body localization transition

    Science.gov (United States)

    Bertrand, Corentin L.; García-García, Antonio M.

    2016-10-01

    We study a one-dimensional XXZ spin chain in a random field on the metallic side of the many-body localization transition by level statistics. For a fixed interaction, and intermediate disorder below the many-body localization transition, we find that, asymptotically, the number variance grows faster than linear with a disorder-dependent exponent. This is consistent with the existence of an anomalous Thouless energy in the spectrum. In noninteracting disordered metals, this is an energy scale related to the typical time for a particle to diffuse across the sample. In the interacting case, it seems related to a more intricate anomalous diffusion process. This interpretation is not fully consistent with recent claims that for intermediate disorder, level statistics are described by a plasma model with power-law decaying interactions whose number variance grows slower than linear. As disorder is further increased, still on the metallic side, the Thouless energy is gradually washed out. In the range of sizes we can explore, level statistics are scale invariant and approach Poisson statistics at the many-body localization transition. Slightly below the many-body localization transition, spectral correlations, well described by critical statistics, are quantitatively similar to those of a high-dimensional, noninteracting, disordered conductor at the Anderson transition.

  15. The influence of structural defects on intra-granular critical currents of bulk MgB2

    OpenAIRE

    Serquis, A.; Liao, X. Z.; Civale, L.; Zhu, Y. T.; Coulter, J. Y.; Peterson, D E; Mueller, F. M.

    2003-01-01

    Bulk MgB2 samples were prepared under different synthesis conditions and analyzed by scanning and transmission electron microscopy. The critical current densities were determined from the magnetization versus magnetic field curves of bulk and powder-dispersed-in-epoxy samples. Results show that through a slow cooling process, the oxygen dissolved in bulk MgB2 at high synthesis temperatures can segregate and form nanometer-sized coherent precipitates of Mg(B,O)2 in the MgB2 matrix. Magnetizati...

  16. Influence of the 3D-2D crossover on the critical current of Nb/Cu multilayers

    DEFF Research Database (Denmark)

    Krasnov, V. M.; Pedersen, Niels Falsig; Oboznov, V. A.

    1994-01-01

    of the dimensional 3D-2D cross-over on the I(c)perpendicular-to was observed. Thus, as the temperature becomes smaller than T2D, hysteresis in the current-voltage characteristic appears and the behavior of the temperature dependence of the I(c)perpendicular-to changes. For T > T2D the diminishing of the hysteresis......(c)perpendicular-to (T) was found. From the theoretical simulations, we have obtained the dependence of the crossover and the critical temperatures of multilayers on the layer thicknesses, the boundary transparency, and layer conductivity....

  17. Effect of strain on the critical current density of Bi-2223 thick films sandwiched between Ag sheets

    Energy Technology Data Exchange (ETDEWEB)

    Jia, J.H. (Academia Sinica, Hefei (China). Inst. of Solid State Physics); Kong, Q.P. (Academia Sinica, Hefei (China). Inst. of Solid State Physics); Wang, S.X. (Academia Sinica, Hefei, Anhui (China). Inst. of Plasma Physics); Han, H.M. (Academia Sinica, Hefei, Anhui (China). Inst. of Plasma Physics)

    1994-08-16

    The tapes of (Bi, Pb)[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub x] (Bi-2223) thick film sandwiched between Ag sheets are known to have very high J[sub c]. In this note, the stress-strain behaviour and the strain dependence of critical current density of the Ag/Bi-2223/Ag tapes are investigated. The microstructure of superconducting thick films subjected to various amounts of deformation was examined with a scanning electron microscope (SEM). (orig.)

  18. Effects of densification of precursor pellets on microstructures and critical current properties of YBCO melt-textured bulks

    Science.gov (United States)

    Setoyama, Yui; Shimoyama, Jun-ichi; Motoki, Takanori; Kishio, Kohji; Awaji, Satoshi; Kon, Koichi; Ichikawa, Naoki; Inamori, Satoshi; Naito, Kyogo

    2016-12-01

    Effects of densification of precursor disks on the density of residual voids and critical current properties for YBCO melt-textured bulk superconductors were systematically investigated. Six YBCO bulks were prepared from precursor pellets with different initial particle sizes of YBa2Cu3Oy (Y123) powder and applied pressures for pelletization. It was revealed that use of finer Y123 powder and consolidation using cold-isostatic-pressing (CIP) with higher pressures result in reduction of residual voids at inner regions of bulks and enhance Jc especially under low fields below the second peak.

  19. Laser-induced modification of the critical current in Y-Ba-Cu-O step-edge Josephson junctions

    Science.gov (United States)

    Adam, Roman; Kula, Witold; Murduck, J. M.; Pettiette-Hall, C.; Sobolewski, Roman

    1996-03-01

    Transport properties of YBa2Cu3O7- x (YBCO) step-edge weak links were measured in the absence and presence of the magnetic field B, both before and after the cw-laser annealing. Depending on the laser power density, either an increase (up to 75%) or decrease (up to 100%) of the junction critical current I c was observed. The I c (B) characteristics of the laser-treated junctions exhibited about 10% variations of the I c (B) periodicity, indicating permanent changes in the junction barrier and/or adjacent YBCO electrodes.

  20. Magneto-elastic behaviour of thin type-II superconducting strip with field-dependent critical current

    Science.gov (United States)

    Xue, Cun; He, An; Yong, Huadong; Zhou, Youhe

    2013-01-01

    The magneto-elastic behavior of thin superconducting strip in perpendicular magnetic field with field-dependent critical current is studied. We calculate numerically the body force, strain, displacement, and thickness changes in the strip for the Bean model and Kim model during the field ascent and descent. The differences in magnetostriction between the Bean model and the Kim model are analyzed. The magnetostriction during one full cycle of the applied field for both models is presented. The results show that magnetostriction loops are different in these models, and at low temperatures Kim model is in better agreement with experiment than Bean model.

  1. Current maternal depression moderates the relation between critical expressed emotion in mothers and depressive symptoms in their adolescent daughters.

    Science.gov (United States)

    Mellick, William; Kalpakci, Allison; Sharp, Carla

    2015-06-30

    Prior studies have examined critical expressed emotion (EE-Crit) in mothers in the intergenerational transmission of depression. However, the potential moderating effect of maternal depression diagnostic status in relation to EE-Crit and youth depressive symptoms has yet to be determined. A total of N=121 biological mother/daughter dyads that differed in maternal depression diagnostic status were recruited for the present study: (1) currently depressed mothers (current depression, n=29); (2) formerly depressed mothers (past depression, n=39); and (3) mothers free from any psychiatric history (healthy controls, n=53). Mothers were administered structured clinical interviews and completed self-report measures of EE-Crit and psychopathology, and daughters self-reported depressive symptoms. Results indicated no significant group differences in EE-Crit; however, current maternal depression status moderated EE-Crit such that the magnitude of the relation between EE-Crit and adolescent depressive symptoms was significantly greater in daughters of currently depressed mothers. These findings highlight the importance of considering current maternal depression, rather than a history of maternal depression, in relation to EE-Crit and adolescent depressive symptoms, providing impetus for future investigations. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. In-field critical current property of IBAD/PLD coated conductors

    Science.gov (United States)

    Fujita, S.; Daibo, M.; Igarashi, M.; Kikutake, R.; Kakimoto, K.; Iijima, Y.; Itoh, M.; Saitoh, T.

    2014-05-01

    REBa2Cu3Oy, (RE : rare earth elements, RE123) coated conductors are expected to show high performance in superconducting applications, due to their high mechanical strength and high current density in magnetic fields. Fujikura has developed ion-beam-assisted-deposition (IBAD) and pulsed-laser-deposition (PLD) technique, and today we routinely manufacture coated conductors with length over 500 m and Ic over 500 A/cm-width at 77 K, self field. We have also been able to fabricate long conductors with higher Ic by thickening RE123 layer. Although Ic performances at 77 K, self field are important, but performances in magnetic fields at lower temperatures below 77 K are more important for coil applications. In this work, we evaluated coated conductors with thick RE123 layer in magnetic fields at low temperatures. All samples are fabricated with long length. We measured samples by four-probe transport method at wide temperature range from 77 K to 10 K by using cryo-cooled cryostat. A conductor with 5.5 μm thick RE123 exhibits high Ic values of 937 A/cm-width at 77 K, self field, 637 A/cm-width at 50 K, 5T and 976 A/cm-width at 40 K, 5T.

  3. Emergency obstetric care availability: a critical assessment of the current indicator.

    Science.gov (United States)

    Gabrysch, Sabine; Zanger, Philipp; Campbell, Oona M R

    2012-01-01

    Monitoring progress in reducing maternal and perinatal mortality requires suitable indicators. The density of emergency obstetric care (EmOC) facilities has been proposed as a potentially useful indicator, but different UN documents make inconsistent recommendations, and its current formulation is not associated with maternal mortality. We compiled recently published indicator benchmarks and distinguished three sources of inconsistency: (i) use of different denominator metrics (per birth and per population), (ii) different assumptions on need for EmOC and for EmOC facilities and (iii) failure to specify facility capacity (birth load). The UN guidelines and handbook require fewer EmOC facilities than the World Health Report 2005 and do not specify capacity for deliveries or staffing levels. We recommend (i) always using births as the denominator for EmOC facility density, (ii) clearly stating assumptions on the proportion of deliveries needing basic and comprehensive emergency obstetric care and the desired proportion of deliveries in EmOC facilities and (iii) specifying facility capacity and staffing and adapting benchmarks for settings with different population density to ensure geographical accessibility.

  4. X-ray Constrained Extremely Localized Molecular Orbitals: Theory and Critical Assessment of the New Technique.

    Science.gov (United States)

    Genoni, Alessandro

    2013-07-09

    Following the X-ray constrained wave function approach proposed by Jayatilaka, we have devised a new technique that allows to extract molecular orbitals strictly localized on small molecular fragments from sets of experimental X-ray structure factors amplitudes. Since the novel strategy enables to obtain electron distributions that have quantum mechanical features and that can be easily interpreted in terms of traditional chemical concepts, the method can be also considered as a new useful tool for the determination and the analysis of charge densities from high-resolution X-ray experiments. In this paper, we describe in detail the theory of the new technique, which, in comparison to our preliminary work, has been improved both treating the effects of isotropic secondary extinctions and introducing a new protocol to halt the fitting procedure against the experimental X-ray scattering data. The performances of the novel strategy have been studied both in function of the basis-sets flexibility and in function of the quality of the considered crystallographic data. The tests performed on four different systems (α-glycine, l-cysteine, (aminomethyl)phosphonic acid and N-(trifluoromethyl)formamide) have shown that the achievement of good statistical agreements with the experimental measures mainly depends on the quality of the crystal structures (i.e., geometry positions and thermal parameters) used in the X-ray constrained calculations. Finally, given the reliable transferability of the obtained Extremely Localized Molecular Orbitals (ELMOs), we envisage to exploit the novel approach to construct new ELMOs databases suited to the development of linear-scaling methods for the refinement of macromolecular crystal structures.

  5. Critical exponents for a transition from integrability to non-integrability via localization of invariant tori in the Hamiltonian system

    Energy Technology Data Exchange (ETDEWEB)

    Leonel, Edson D; De Oliveira, Juliano A; Saif, Farhan, E-mail: edleonel@rc.unesp.br [Departamento de EstatIstica, Matematica Aplicada e Computacao, UNESP-Univ. Estadual Paulista, Av. 24A, 1515, Bela Vista, 13506-900 Rio Claro, Sao Paulo (Brazil)

    2011-07-29

    Critical exponents that describe a transition from integrability to non-integrability in a two-dimensional, nonlinear and area-preserving map are obtained via localization of the first invariant spanning curve (invariant tori) in the phase space. In a general class of systems, the position of the first invariant tori is estimated by reducing the mapping of the system to the standard mapping where a transition takes place from local to global chaos. The phase space of the mapping shows a large chaotic sea surrounding periodic islands and limited by a set of invariant tori whose position of the first of them depends on the control parameters. The formalism leads us to obtain analytically critical exponents that describe the behaviour of the average variable (action) along the chaotic sea. The result is compared to several models in the literature confirming the approach is of large interest. The formalism used is general and the procedure can be extended to many other different systems. (fast track communication)

  6. A critical review of engineered nanomaterial release data: Are current data useful for material flow modeling?

    Science.gov (United States)

    Caballero-Guzman, Alejandro; Nowack, Bernd

    2016-06-01

    Material flow analysis (MFA) is a useful tool to predict the flows of engineered nanomaterials (ENM) to the environment. The quantification of release factors is a crucial part of MFA modeling. In the last years an increasing amount of literature on release of ENM from materials and products has been published. The purpose of this review is to analyze the strategies implemented by MFA models to include these release data, in particular to derive transfer coefficients (TC). Our scope was focused on those articles that analyzed the release from applications readily available in the market in settings that resemble average use conditions. Current MFA studies rely to a large extent on extrapolations, authors' assumptions, expert opinions and other informal sources of data to parameterize the models. We were able to qualitatively assess the following aspects of the release literature: (i) the initial characterization of ENM provided, (ii) quantitative information on the mass of ENM released and its characterization, (iii) description of transformation reactions and (iv) assessment of the factors determining release. Although the literature on ENM release is growing, coverage of exposure scenarios is still limited; only 20% of the ENMs used industrially and 36% of the product categories involved have been investigated in release studies and only few relevant release scenarios have been described. Furthermore, the information provided is rather incomplete concerning descriptions and characterizations of ENMs and the released materials. Our results show that both the development of methods to define the TCs and of protocols to enhance assessment of ENM release from nano-applications will contribute to increase the exploitability of the data provided for MFA models. The suggestions we provide in this article will likely contribute to an improved exposure modeling by providing ENM release estimates closer to reality.

  7. A critical overview of the current myofascial pain literature - October 2015.

    Science.gov (United States)

    Dommerholt, Jan; Grieve, Rob; Hooks, Todd; Layton, Michelle

    2015-10-01

    The number of publications about myofascial pain and trigger points (TrP) seems to increase every year. In the current overview we include 27 articles published in past months. The Basic Review section includes articles about the presence and characteristics of TrPs in various neck and shoulder muscles, the correlation between referred pain from active TrPs and knee osteoarthritis, and an anatomical study exploring whether the location of TrPs may be related to the nerve innervation of muscles. Zuil-Escobar and colleagues from Spain considered the intra-rater reliability of the identification of latent TrPs in several leg muscles and the possible correlation of TrP and the presence of a lower medial longitudinal arch. In the section on manual approaches, contributing author Rob Grieve and colleagues continue their studies of TrPs in the lower extremity muscles, while Méndez-Rebolledo and colleagues studied the impact of cross taping and compression. Dry needling (DN) continues to be a topic of interest. We included twelve papers addressing a wide range of topics, such as the effectiveness and safety of DN, and the impact of DN on proprioception, spasticity, and fibromyalgia. Two papers investigated the utilization of repetitive transcranial magnetic stimulation and laser on TrPs, The final section on other clinical studies and reviews includes 8 papers. The studies originated in thirteen different countries with Spain leading the charts with 7 contributions to the literature, followed by Brazil with four. As we have mentioned in previous editions of this literature overview, many studies suffer from very small sample sizes, which makes it difficult to reach definitive conclusions. Nevertheless, myofascial pain continues to be a topic of interest to researchers and clinicians around the globe. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Significant reduction of critical currents in MRAM designs using dual free layer with perpendicular and in-plane anisotropy

    Science.gov (United States)

    Suess, D.; Vogler, C.; Bruckner, F.; Sepehri-Amin, H.; Abert, C.

    2017-06-01

    One essential feature in magnetic random access memory cells is the spin torque efficiency, which describes the ratio of the critical switching current to the energy barrier. In this paper, it is reported that the spin torque efficiency can be improved by a factor of 3.2 by the use of a dual free layer device, which consists of one layer with perpendicular crystalline anisotropy and another layer with in-plane crystalline anisotropy. Detailed simulations solving the spin transport equations simultaneously with the micromagnetics equation were performed in order to understand the origin of the switching current reduction by a factor of 4 for the dual layer structure compared to a single layer structure. The main reason could be attributed to an increased spin accumulation within the free layer due to the dynamical tilting of the magnetization within the in-plane region of the dual free layer.

  9. A new model analysis of the third harmonic voltage in inductive measurement for critical current density of superconducting films

    Institute of Scientific and Technical Information of China (English)

    Zhang Xu; Wu Zhi-Zhen; Zhou Tie-Ge; He Ming; Zhao Xin-Jie; Yan Shao-Lin; Fang Lan

    2011-01-01

    The critical current density Jc is one of the most important parameters of high temperature superconducting films in superconducting applications, such as superconducting filter and superconducting Josephson devices. This paper presents a new model to describe inhomogeneous current distribution throughout the thickness of superconducting films applying magnetic field by solving the differential equation derived from Maxwell equation and the second London equation. Using this model, it accurately calculates the inductive third-harmonic voltage when the film applying magnetic field with the inductive measurement for Jc. The theoretic curve is consistent with the experimental results about measuring superconducting film, especially when the third-harmonic voltage just exceeds zero. The Jc value of superconducting films determined by the inductive method is also compared with results measured by four-probe transport method. The agreements between inductive method and transport method are very good.

  10. Influence of critical current density on magnetic force of HTSC bulk above PMR with 3D-modeling numerical solutions

    Science.gov (United States)

    Lu, Yiyun; Qin, Yujie

    2015-09-01

    Numerical simulations of thermo-electromagnetic properties of a high temperature superconducting (HTS) bulk levitating over a permanent magnetic guideway (PMG) are performed by resorting to the quasistatic approximation of the H-method coupling with the classical description of the heat conduction equation. The numerical resolving codes are practiced with the help of the finite element program generation system (FEPG) platform using finite element method (FEM). The E-J power law is used to describe the electric current nonlinear characteristics of HTS bulk. The simulation results show that the heat conduction and the critical current density are tightly relative to the thermal effects of the HTS bulk over the PMG. The heat intensity which responds to the heat loss of the HTS bulk is mainly distributed at the two bottom-corners of the bulk sample.

  11. The Influence of Surface Morphology of Buffer Layer on the Critical Current Density in YBCO Coated Conductors

    Directory of Open Access Journals (Sweden)

    Jie Xiong

    2013-01-01

    Full Text Available 1 μm-thick YBa2Cu3O7-δ (YBCO films were grown on the Y2O3/yttria stabilized zirconia (YSZ/CeO2 buffer layers with different surface morphologies using direct-current sputtering. The critical current density (Jc value of YBCO was 1.1 MA/cm2 when the root mean square surface roughness (Rrms of the buffer layer was 2.5 nm. As the Rrms of the buffer layer increased to 15 nm, the Jc decreased to 0.3 MA/cm2. X-ray diffraction and scanning electron microscopy showed the strong relevance of the evolution of the structure and surface morphologies of YBCO films with the buffer layer of different Rrms. A model was proposed to explain the influence of surface morphology on the superconducting properties of YBCO films.

  12. Non-Fermi Liquid Behavior Close to a Quantum Critical Point in a Ferromagnetic State without Local Moments

    Directory of Open Access Journals (Sweden)

    E. Svanidze

    2015-03-01

    Full Text Available A quantum critical point (QCP occurs upon chemical doping of the weak itinerant ferromagnet Sc_{3.1}In. Remarkable for a system with no local moments, the QCP is accompanied by non-Fermi liquid behavior, manifested in the logarithmic divergence of the specific heat both in the ferro-and the paramagnetic states, as well as linear temperature dependence of the low-temperature resistivity. With doping, critical scaling is observed close to the QCP, as the critical exponents δ, γ, and β have weak composition dependence, with δ nearly twice and β almost half of their respective mean-field values. The unusually large paramagnetic moment μ_{PM}∼1.3μ_{B}/F.U. is nearly composition independent. Evidence for strong spin fluctuations, accompanying the QCP at x_{c}=0.035±0.005, may be ascribed to the reduced dimensionality of Sc_{3.1}In, associated with the nearly one-dimensional Sc-In chains.

  13. Summertime coastal current reversal opposing offshore forcing and local wind near the middle east coast of Korea: Observation and dynamics

    Science.gov (United States)

    Park, Jae-Hyoung; Chang, Kyung-Il; Nam, SungHyun

    2016-07-01

    A 6 year long current measurement at a buoy station off the middle east coast of Korea reveals an equatorward reversal of coastal current in summer opposing poleward local wind stress and offshore boundary current. The current reversal extends about 40 km offshore from the coast and is concurrent with warming and freshening of water column. Estimates of the depth-averaged alongshore momentum balance suggest a major balance between the alongshore pressure gradient and the lateral friction. Sources of the pressure gradient for the summertime current reversal are identified as the alongshore buoyancy gradient driven by the wind curl gradient and the prevalence of warmer and lower salinity water in the north. Alongshore pressure gradient and velocity induced by the wind curl gradient are quantified, which yields the observed seasonal current reversal.

  14. Enhancement of the high-magnetic-field critical current density of superconducting MgB2 by proton irradiation.

    Science.gov (United States)

    Bugoslavsky, Y; Cohen, L F; Perkins, G K; Polichetti, M; Tate, T J; Gwilliam, R; Caplin, A D

    2001-05-31

    Magnesium diboride, MgB2, has a relatively high superconducting transition temperature, placing it between the families of low- and high-temperature (copper oxide based) superconductors. Supercurrent flow in MgB2 is unhindered by grain boundaries, making it potentially attractive for technological applications in the temperature range 20-30 K. But in the bulk material, the critical current density (Jc) drops rapidly with increasing magnetic field strength. The magnitude and field dependence of the critical current are related to the presence of structural defects that can 'pin' the quantized magnetic vortices that permeate the material, and a lack of natural defects in MgB2 may be responsible for the rapid decline of Jc with increasing field strength. Here we show that modest levels of atomic disorder induced by proton irradiation enhance the pinning of vortices, thereby significantly increasing Jc at high field strengths. We anticipate that either chemical doping or mechanical processing should generate similar levels of disorder, and so achieve performance that is technologically attractive in an economically viable way.

  15. Enhanced in-field critical currents of YBCO second-generation (2G) wire by Dy additions

    Energy Technology Data Exchange (ETDEWEB)

    Long, N [Industrial Research Ltd, PO Box 31-310, Lower Hutt (New Zealand); Strickland, N [Industrial Research Ltd, PO Box 31-310, Lower Hutt (New Zealand); Chapman, B [Industrial Research Ltd, PO Box 31-310, Lower Hutt (New Zealand); Ross, N [Industrial Research Ltd, PO Box 31-310, Lower Hutt (New Zealand); Xia, J [Industrial Research Ltd, PO Box 31-310, Lower Hutt (New Zealand); Li, X [American Superconductor Corporation, Westborough, MA 01581 (United States); Zhang, W [American Superconductor Corporation, Westborough, MA 01581 (United States); Kodenkandath, T [American Superconductor Corporation, Westborough, MA 01581 (United States); Huang, Y [American Superconductor Corporation, Westborough, MA 01581 (United States); Rupich, M [American Superconductor Corporation, Westborough, MA 01581 (United States)

    2005-12-15

    The addition of dysprosium oxide nanoparticles is shown to improve the critical current in perpendicular magnetic fields for second-generation (2G) wire formed by metal-organic deposition (MOD). Typical enhancements in J{sub c} are from 0.17 MA cm{sup -2} to over 0.33 MA cm{sup -2} at 77 K and B{sub perp} = 1.5 T. TEM analysis shows that we are introducing (Y,Dy){sub 2}O{sub 3} nanoparticles with dimensions of 10-50 nm. A simple theoretical analysis shows that the maximum pinning effect for additions is expected at excess concentrations of approximately 70% DyO{sub 1.5}, i.e. for YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}+0.7DyO{sub 1.5} if the added nanoparticles are randomly dispersed and a strong pinning model is valid. An interesting feature is that the critical current in parallel field is reduced in these samples. We present evidence that shows this may be due to reduced planar defects in the YBCO.

  16. Critical current degradation behaviour of GdBCO CC tapes in pure torsion and combined tension-torsion modes

    Science.gov (United States)

    Gorospe, Alking; Bautista, Zhierwinjay; Shin, Hyung-Seop

    2016-10-01

    Coated conductor (CC) tapes utilized in high-current-density superconducting cables are commonly subjected to different loading modes, primarily torsion and tension especially in the case of twisted stacked-tape cable. Torsion load can occur due to twisting along the length or when winding the CC tapes around a former, while tension load can occur due to pre-tension when coiled and as a hoop stress when the coil is energized. In this study, electromechanical properties of single CC tapes under torsion load were investigated using a new test apparatus. The results could provide basic information for cable designers to fully characterize stacked cables. Copper-electroplated and brass-laminated CC tapes fabricated with different deposition techniques were subjected to pure torsion and combined tension-torsion loading. The critical current, I c degradation behaviours of CC tapes under torsional deformation were examined. Also, the effect of further external lamination on the I c degradation behaviour of the CC tapes under such loading conditions was investigated. In the case of the combined tension-torsion test, short samples were subjected to twist pitches of 200 mm and 100 mm. Critical parameters including reversible axial stress and strain in such twist pitch conditions were also investigated.

  17. Managerial accounting in local authorities : An overview of the current/real situation

    OpenAIRE

    Letort, Frederique

    2016-01-01

    This thesis raises the question of the appropriate type of management accounting in local government. Thepurpose of this research is to study how local authorities have been using managerial accounting. Originally,managerial accounting was meant for companies and using it for non-profit organizations, which have differentpurposes, is problematic. Studying the literature on this topic shows that the use of this management tool bylocal authorities since the 1980s has not been smooth, as it orig...

  18. Stochastic macromodel of magnetic tunnel junction resistance variation and critical current dependence on resistance variation for SPICE simulation

    Science.gov (United States)

    Choi, Juntae; Song, Yunheub

    2017-04-01

    The resistance distribution of a magnetic tunnel junction (MTJ) shows nonuniformity according to various MTJ parameters. Moreover, this resistance variation leads to write-current density variation, which can cause serious problems when designing peripheral circuits for spin transfer torque magnetoresistance random access memory (STT-MRAM) and commercializing gigabit STT-MRAM. Therefore, a macromodel of MTJ including resistance, tunneling magnetoresistance ratio (TMR), and critical current variations is required for circuit designers to design MRAM peripheral circuits, that can overcome the various effects of the variations, such as write failure and read failure, and realize STT-MRAM. In this study, we investigated a stochastic behavior macromodel of the write current dependence on the MTJ resistance variation. The proposed model can possibly be used to analyze the write current density in relation to the resistance and TMR variations of MTJ with various parameter variations. It can be very helpful for designing STT-MRAM circuits and simulating the operation of STT-MRAM devices considering MTJ variations.

  19. Direct observation of current in type-I edge-localized-mode filaments on the ASDEX upgrade tokamak

    DEFF Research Database (Denmark)

    Vianello, N.; Zuin, M.; Cavazzana, R.;

    2011-01-01

    Magnetically confined plasmas in the high confinement regime are regularly subjected to relaxation oscillations, termed edge localized modes (ELMs), leading to large transport events. Present ELM theories rely on a combined effect of edge current and the edge pressure gradients which result in in...

  20. The estrogen receptor alpha nuclear localization sequence is critical for fulvestrant-induced degradation of the receptor.

    Science.gov (United States)

    Casa, Angelo J; Hochbaum, Daniel; Sreekumar, Sreeja; Oesterreich, Steffi; Lee, Adrian V

    2015-11-01

    Fulvestrant, a selective estrogen receptor down-regulator (SERD) is a pure competitive antagonist of estrogen receptor alpha (ERα). Fulvestrant binds ERα and reduces the receptor's half-life by increasing protein turnover, however, its mechanism of action is not fully understood. In this study, we show that removal of the ERα nuclear localization sequence (ERΔNLS) resulted in a predominantly cytoplasmic ERα that was degraded in response to 17-β-estradiol (E2) but was resistant to degradation by fulvestrant. ERΔNLS bound the ligands and exhibited receptor interaction similar to ERα, indicating that the lack of degradation was not due to disruption of these processes. Forcing ERΔNLS into the nucleus with a heterologous SV40-NLS did not restore degradation, suggesting that the NLS domain itself, and not merely receptor localization, is critical for fulvestrant-induced ERα degradation. Indeed, cloning of the endogenous ERα NLS onto the N-terminus of ERΔNLS significantly restored both its nuclear localization and turnover in response to fulvestrant. Moreover, mutation of the sumoylation targets K266 and K268 within the NLS impaired fulvestrant-induced ERα degradation. In conclusion, our study provides evidence for the unique role of the ERα NLS in fulvestrant-induced degradation of the receptor.

  1. The Critical Richardson Number and Limits of Applicability of Local Similarity Theory in the Stable Boundary Layer

    Science.gov (United States)

    Grachev, Andrey A.; Andreas, Edgar L.; Fairall, Christopher W.; Guest, Peter S.; Persson, P. Ola G.

    2013-04-01

    Measurements of atmospheric turbulence made over the Arctic pack ice during the Surface Heat Budget of the Arctic Ocean experiment (SHEBA) are used to determine the limits of applicability of Monin-Obukhov similarity theory (in the local scaling formulation) in the stable atmospheric boundary layer. Based on the spectral analysis of wind velocity and air temperature fluctuations, it is shown that, when both the gradient Richardson number, Ri, and the flux Richardson number, Rf, exceed a `critical value' of about 0.20-0.25, the inertial subrange associated with the Richardson-Kolmogorov cascade dies out and vertical turbulent fluxes become small. Some small-scale turbulence survives even in this supercritical regime, but this is non-Kolmogorov turbulence, and it decays rapidly with further increasing stability. Similarity theory is based on the turbulent fluxes in the high-frequency part of the spectra that are associated with energy-containing/flux-carrying eddies. Spectral densities in this high-frequency band diminish as the Richardson-Kolmogorov energy cascade weakens; therefore, the applicability of local Monin-Obukhov similarity theory in stable conditions is limited by the inequalities Ri < Ri cr and Rf < Rf cr. However, it is found that Rf cr = 0.20-0.25 is a primary threshold for applicability. Applying this prerequisite shows that the data follow classical Monin-Obukhov local z-less predictions after the irrelevant cases (turbulence without the Richardson-Kolmogorov cascade) have been filtered out.

  2. Current organic waste recycling and the potential for local recycling through urban agriculture in Metro Manila.

    Science.gov (United States)

    Hara, Yuji; Furutani, Takashi; Murakami, Akinobu; Palijon, Armando M; Yokohari, Makoto

    2011-11-01

    Using the solid waste management programmes of three barangays (the smallest unit of local government in the Philippines) in Quezon City, Metro Manila, as a case study, this research aimed to further the development of efficient organic waste recycling systems through the promotion of urban agricultural activities on green and vacant spaces. First, the quantity of organic waste and compost produced through ongoing barangay projects was measured. The amount of compost that could potentially be utilized on farmland and vacant land within the barangays was then identified to determine the possibility of a local recycling system. The results indicate that, at present, securing buyers for compost is difficult and, therefore, most compost is distributed to large neighbouring farm villages. However, the present analysis of potential compost use within the barangay demonstrates that a more local compost recycling system is indeed feasible.

  3. Field-aligned currents in Saturn's magnetosphere: Local time dependence of southern summer currents in the dawn sector between midnight and noon

    Science.gov (United States)

    Hunt, G. J.; Cowley, S. W. H.; Provan, G.; Bunce, E. J.; Belenkaya, E. S.; Alexeev, I. I.; Kalegaev, V. V.; Dougherty, M. K.; Coates, A. J.

    2016-12-01

    We examine and compare the magnetic field perturbations associated with field-aligned ionosphere-magnetosphere coupling currents at Saturn, observed by the Cassini spacecraft during two sequences of highly inclined orbits in 2006/7 and 2008 under late southern summer conditions. These sequences explore the southern currents in the dawn-noon and midnight sectors, respectively. This allows investigation of possible origins of the local time (LT) asymmetry in auroral Saturn kilometric radiation (SKR) emissions, which peak in power at 8 h LT in the dawn-noon sector. We first show that the dawn-noon field data generally have the same four-sheet current structure as found previously in the midnight data, and that both are similarly modulated by "planetary period oscillation" (PPO) currents, these being associated with the 10.7 h magnetic field oscillations observed throughout Saturn's magnetosphere. We then separate the averaged PPO-independent (e.g., subcorotation) and PPO-related currents for both LT sectors using the latter current system symmetry properties. Surprisingly, we find that the PPO-independent currents are essentially identical within uncertainties in the dawn-dusk and midnight sectors, thus providing no explanation for the LT dependence of the SKR emissions. The main PPO-related currents are, however, found to be slightly stronger and narrower in latitudinal width at dawn-noon than at midnight, leading to estimated precipitating electron powers, and hence emissions, that are on average a factor of 1.3 larger at dawn-noon than at midnight, inadequate to account for the observed LT asymmetry in SKR power by a factor of 2.7. Some other factor must also be involved, such as a LT asymmetry in the hot magnetospheric auroral source electron population.

  4. Mechanism of thickness dependence of critical current density in HTS YBCO film and its elimination using nano-engineering

    Science.gov (United States)

    Wang, Xiang

    The most promising characteristic of a High Temperature Superconductor (HTS) is its ability to carry larger electrical current at liquid nitrogen boiling temperature and strong applied magnetic field with minimal dissipation. Numerous large scale applications such as HTS transmission cables, HTS magnets and HTS motors have been developed using HTS materials. The major limitation that prevents its wide commercialization is its high cost-to-performance ratio. However, the effort to further improve HTS current carrying capability is jeopardized by a mysterious thickness dependence of the critical current density (Jc) --- Jc monotonically decreases with increasing thickness (t) at 77 K and self-field (SF). This poses a great challenge for both HTS applications and the understanding of vortex dynamics. What further complicates this issue is the complex defect structure in HTS films as well as the creep nature of magnetic vortices at a finite temperature. After a systematic study of the temperature and magnetic field effects on Jc--t, we conclude that Jc--t is most likely the result of a collective pinning effect dictated by a random pinning potential. Besides that, thermal fluctuations also alter Jc--t in a predictable way. Therefore, by either modifying the vortex structure or pinning structure, J c--t can be eliminated. Indeed, a thin film J c has been restored in a HTS/insulator/HTS trilayer while the magnetic coupling is weakened. Moreover, Jc--t has been removed when the random distributed point pins are overpowered by strong linear defects.

  5. Non-inductive current built-up by local electron cyclotron heating and current drive with a 28 GHz focused beam on QUEST

    Science.gov (United States)

    Onchi, Takumi; Idei, Hiroshi; Hasegawa, Makoto; Ohwada, Hiroaki; Zushi, Hideki; Hanada, Kazuaki; Kariya, Tsuyoshi; Mishra, Kishore; Shikama, Taichi; Quest Team

    2016-10-01

    The plasma current can be driven solely by injecting electron cyclotron waves (ECWs) in spherical tokamak (ST) configuration. A system of 28 GHz gyrotron (maximum power: 270 kW) is renewed and reinstalled on QUEST. A focused ECW beam, whose diameter is about 5 cm at the second harmonic resonance, is injected for local ECW heating and current drive. The local power density at resonance exceeds 75 MW/m2 at an injection power of 150 kW. The incident ECW polarization can be adjusted employing the phase shifter consisting of two corrugated plates. During 1.25 second pulse of ECH, plasma current is built up to Ip = 70 kA fully non-inductively with a core electron density of ne > 1018 m-3. The closed flux in such ST plasma is determined at the inboard limiter on the center stack. Energetic electrons are also responsible for the pressure and equilibrium. This work is supported by JSPS KAKENHI (15H04231, 15K17800), NIFS Collaboration Research program (NIFS13KUTR085, NIFS11KUTR069, NIFS16KUTR114).

  6. Magnetic signature of current carrying edge localized modes filaments on the Joint European Torus tokamak

    DEFF Research Database (Denmark)

    Migliucci, P.; Naulin, Volker

    2010-01-01

    Fast magnetic pickup coils are used in forward modeling to match parameters in a simple edge localized mode (ELM) filament model. This novel method allows us to determine key parameters for the evolution of the ELM filaments, as effective mode number, radial and toroidal velocities, and average...

  7. The Critical Richardson Number and Limits of Applicability of Local Similarity Theory in the Stable Boundary Layer

    CERN Document Server

    Grachev, Andrey A; Fairall, Christopher W; Guest, Peter S; Persson, P Ola G

    2012-01-01

    Measurements of atmospheric turbulence made over the Arctic pack ice during the Surface Heat Budget of the Arctic Ocean experiment (SHEBA) are used to determine the limits of applicability of Monin-Obukhov similarity theory (in the local scaling formulation) in the stable atmospheric boundary layer. Based on spectral analysis of wind velocity and air temperature fluctuations, it is shown that when both gradient Richardson number, Ri, and flux Richardson number, Rf, exceed a 'critical value' about 0.20-0.25, the inertial subrange associated with the Kolmogorov cascade dies out and vertical turbulent fluxes become small. Some small-scale turbulence survives even in the supercritical regime, but this is non-Kolmogorov turbulence and it decays rapidly with further increasing stability. Similarity theory is based on the turbulent fluxes in the high-frequency part of the spectra that are associated with energy-containing/flux-carrying eddies. Spectral densities in this high-frequency band diminish as the Kolmogorov...

  8. Critical length of disorder for the onset of localization in YBa2Cu3O6.9films

    Science.gov (United States)

    Gauzzi, Andrea; Joensson, B. J.; Clerc-Dubois, Arnaud; Pavuna, Davor

    1996-07-01

    We report a combined analysis of resistivity and x-ray diffraction rocking curve measurements on c-axis oriented YBA2Cu3O6.9 films epitaxially grown on (100) SrTiO3 and LaAlO3 by ion-beam sputtering. We find that the growth-induced reduction of long-range lattice order in the films begins to depress superconductivity and normal conductivity at a critical value of lattice coherence length of approximately equals 10 and 5 nm for the two above types of substrates respectively. Evidence for disorder-induced localization is given by a deviation from linearity of the temperature-dependence of the resistivity which scales as the reduction of superconducting critical temperature. Similar nonlinear dependence observed in slightly reduced or lightly Co-doped samples suggests that the disorder in our films significantly affects the CuO chains. Our analysis of the paraconductivity term in the films gives evidence for the enhancement of the superconducting fluctuations by the disorder.

  9. Influence of powder pre-annealing on the phase formation and critical current of Bi-2223/Ag tapes

    DEFF Research Database (Denmark)

    Chen, X.P.; Grivel, Jean-Claude; Li, M.Y.;

    2004-01-01

    the precursor with Ca2PbO4 phase (tape T1) had lower transformation rate of 2223 phase than tapes fabricated using the precursor with 3321 phase (tape T2). SEM results show that a large fraction of secondary phases with big particle size was formed in the tape T1 during the subsequent sintering, which might......The influence of precursor powders with different lead-rich phases, such as Ca2PbO4 and Pb-3(Sr,Bi)(3)Ca2CuOy (3 3 2 1), on the phase formation and critical current of Bi-2223/Ag tapes has been studied. Three precursors with different phase assemblages were prepared and used to make the tapes...

  10. Temperature and magnetic field dependence of the critical current in polycrystalline Ba2YCu3O(y)

    Science.gov (United States)

    Obara, H.; Yamasaki, H.; Kimura, Y.; Higashida, Y.; Ishihara, T.

    Temperature and magnetic field dependence on the critical current density Jc of polycrystalline high-Tc oxide superconductor, Ba2YCu3O(y), have been measured. In the low magnetic field range, 0.6 to about 7 kOe, the Jc behavior changed at around 70 K. Below 70 K, Jc showed different temperature dependence between field cooling and zero-field cooling, that is, the Jc value measured when the sample was cooled in a fixed magnetic field, was different from that measured when the sample was cooled in zero magnetic field and then a magnetic field was applied. Above 70 K, however, such different temperature dependence on Jc was not observed. These experimental results can be attributed to the effects of anisotropy. A crossover between the two- and three-dimensional superconductivity is considered to occur.

  11. Intrinsic strain effect on critical current in Cu-stabilized GdBCO coated conductor tapes with different substrates

    Science.gov (United States)

    Shin, Hyung-Seop; Dedicatoria, Marlon J.

    2013-05-01

    The intrinsic strain effect on critical current, Ic in Cu-stabilized GdBCO coated conductor (CC) tapes under bending and uniaxial tension has been investigated. The bending deformation tolerance of Ic in GdBCO CC tapes, fabricated by reactive co-evaporation by deposition and reaction (RCE-DR) with substrate materials of Hastelloy and stainless steel and fabricated by the metal organic chemical vapour deposition (MOCVD) process was evaluated. The intrinsic strain response of Ic under bending was found to be independent of the fabrication process, the substrate material and the geometry of the sample. For samples with a Hastelloy substrate, the intrinsic strain response of Ic/Icmax under bending was well correlated with those under uniaxial tension. However, for samples with a stainless steel substrate, these had a large strain sensitivity for Ic under uniaxial tension even though this showed a much higher irreversible strain limit up to 1.05%.

  12. Fabrication of superconductor–ferromagnet–insulator–superconductor Josephson junctions with critical current uniformity applicable to integrated circuits

    Science.gov (United States)

    Ito, Hiroshi; Taniguchi, Soya; Ishikawa, Kouta; Akaike, Hiroyuki; Fujimaki, Akira

    2017-03-01

    Nb Josephson junctions (JJs) were fabricated with a Pd89Ni11 ferromagnetic interlayer and an AlO x tunnel barrier layer for use in large-scale superconducting integrated circuits. The junctions had a small critical current (I c) spread, where the standard deviation 1σ was less than 2% at 4.2 K for junctions with the same designed size. It was observed that the electrical behavior of the junctions could be controlled by manipulating the film thickness of the PdNi interlayer. The junctions behaved as a π-JJ for thicknesses of 9 and 11 nm, showing 1σ in the I c spread of 1.2% for 9 nm.

  13. The role of interfacial defects in enhancing the critical current density of YBa2Cu3O7-delta coatings

    Energy Technology Data Exchange (ETDEWEB)

    Foltyn, Stephen R [Los Alamos National Laboratory; Wang, Haiyan [Los Alamos National Laboratory; Civale, Leonardo [Los Alamos National Laboratory; Maiorov, Boris A [Los Alamos National Laboratory; Jia, Quanxi [Los Alamos National Laboratory

    2009-01-01

    The critical current density (J{sub c}) of YBa{sub 2}Cu{sub 3}0{sub 7-{delta}} (YBCO) films can approach 10 MA/cm{sup 2} at 77 K in self field , but only for very thin films. We have shown previously that strong thickness dependence results if J{sub c} is enhanced near the film-substrate interface. In the present work we investigate interfacial enhancement using laser-deposited YBCO films on NdGaO{sub 3} substrates, and find that we can adjust deposition conditions to switch the enhancement on and off. Interestingly, we find that the 'on' state is accompanied by interfacial misfit dislocations, establishing an unambiguous correlation between enhanced J{sub c} and dislocations at the film-substrate interface.

  14. Effect of various mechanical deformation processes on critical current density and microstructure in MgB2 tapes and wires

    Science.gov (United States)

    Zhou, Sihai; Pan, Alexey V.; Liu, Huakun; Horvat, Joseph; Dou, Shixue

    2002-11-01

    MgB2 tapes and wires have been prepared by the in situ reaction method. Two cycle drawing and groove-rolling were used for the mechanic deformation of the samples. The critical current density, Jc, as a function of applied magnetic field, Ba, was measured and compared for all the prepared samples. The influence of the different processing at its different stages on the MgB2 microstructure was studied by scanning electron microscopy. Weak links introduced in the superconducting core after the second cycle mechanical deformation could not be re-joined with a consecutive heat treatment. Accordingly, for these samples Jc(Ba) turned out to decrease significantly faster in an increasing field than for samples prepared with one-cycle processing.

  15. Continuous Renal Replacement Therapy: Reviewing Current Best Practice to Provide High-Quality Extracorporeal Therapy to Critically Ill Patients.

    Science.gov (United States)

    Connor, Michael J; Karakala, Nithin

    2017-07-01

    Continuous renal replacement therapy (CRRT) use continues to expand globally. Despite improving technology, CRRT remains a complex intervention. Delivery of high-quality CRRT requires close collaboration of a multidisciplinary team including members of the critical care medicine, nephrology, nursing, pharmacy, and nutrition support teams. While significant gaps in medical evidence regarding CRRT persist, the growing evidence base supports evolving best practice and consensus to define high-quality CRRT. Unfortunately, there is wide variability in CRRT operating characteristics and limited uptake of these best practices. This article will briefly review the current best practice on important aspects of CRRT delivery including CRRT dose, anticoagulation, dialysis vascular access, fluid management, and drug dosing in CRRT. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  16. Investigation of local tunneling current noise spectra on the silicon crystal surfaces by means of STM/STS

    Energy Technology Data Exchange (ETDEWEB)

    Mantsevich, V. N., E-mail: vmantsev@spmlab.phys.msu.su; Maslova, N. S. [Moscow State University, Department of Physics (Russian Federation); Cao, G. Y. [Chinese Academy of Sciences, Wuhan Institute of Physics and Mathematics (China)

    2015-08-15

    We report on a careful analysis of the local tunneling conductivity by means of ultra-high vacuum scanning tunneling microscopy/spectroscopy (STM/STS) technique in the vicinity of low-dimensional structures on the Si(111)–(7 × 7) and Si(110)–(16 × 2) surfaces. The power-law exponent α of low-frequency tunneling current noise spectra is investigated for different values of the tunneling contact parameters: relaxation rates, the localized state coupling, and the tunneling barrier width and height.

  17. Relative roles of local disturbance, current climate and palaeoclimate in determining phylogenetic and functional diversity in Chinese forests

    DEFF Research Database (Denmark)

    Feng, Gang; Mi, Xiangcheng; Bøcher, Peder Klith;

    2014-01-01

    studied, their relative importance for other aspects of diversity, notably phylogenetic and functional diversity is so far little studied. Here, we link data from large Chinese forest plots to data on current and Last Glacial Maximum (LGM) climate as well as local disturbance regimes to study...... their relative roles in determining woody plant phylogenetic and functional diversity in this important hotspot for woody plant diversity. Local disturbance was the best predictor of functional diversity as represented by maximum canopy height (Hmax), probably reflecting the dominant role of competition...

  18. Enhancement in the critical current density of C-doped MgB2 wire using a polyacrylic acid dopant.

    Science.gov (United States)

    Lee, Seung Muk; Hwang, Soo Min; Lee, Chang Min; Kim, Won; Joo, Jinho; Lim, Jun Hyung; Kim, Chan-Joong; Hong, Gye-Won

    2012-02-01

    C-doped MgB2 wires were fabricated from a polyacrylic acid (PAA) using a conventional in-situ PIT technique. The effects of the PAA content on the lattice parameter, microstructure, critical temperature (Tc) and critical current density (Jc) were examined. With increasing PAA content, the amount of MgO in the sample increased but the crystallinity, a-axis lattice parameter, and Tc of MgB2 wires decreased, indicating that the C that decomposed from PAA during heat treatment had substituted for B. All doped samples exhibited a higher Jc than the undoped sample at high magnetic field, and the Jc(B) property improved with increasing PAA content: for the 7 wt% doped sample, the Jc was approximately 3-times higher than that of the pristine sample (1.28 kA/cm2 vs. 3.43 kA/cm2) at 5 K and 6.6 T. The improved Jc(B) of the doped sample was attributed to the decreased grain size, enlarged lattice distortion and increased C doping level.

  19. Network excitability in a model of chronic temporal lobe epilepsy critically depends on SK channel-mediated AHP currents.

    Science.gov (United States)

    Schulz, Robert; Kirschstein, Timo; Brehme, Hannes; Porath, Katrin; Mikkat, Ulrike; Köhling, Rüdiger

    2012-01-01

    Hippocampal CA1 pyramidal neurons generate an after-hyperpolarization (AHP) whose medium component is thought to be generated by small-conductance Ca(2+)-activated K(+) channels (SK channels). Neuronal excitability is increased in epilepsy, and the AHP in turn is fundamentally involved in regulation of cellular excitability. We therefore investigated the involvement of the SK channel-mediated AHP in controlling cell and network excitability in the pilocarpine model epilepsy. Both acutely isolated CA1 pyramidal cells and isolated hippocampal slices were investigated in terms of the impact of SK channel-mediated AHP on hyperexcitability. Our findings show that pilocarpine-treated chronically epileptic rats exhibit significantly reduced SK channel-mediated hyperpolarizing outward current which was accompanied by a significant decrease in the somatic AHP. Paradoxically, inhibiting SK channels strongly exacerbated 0-Mg(2+)-induced epileptiform activity in slices from pilocarpine-treated animals, while having a significantly smaller effect in control tissue. This suggests that in chronically epileptic tissue, network excitability very critically depends on the remaining SK-channel mediated AHP. Additional real-time RT-PCR and semiquantitative Western blot experiments revealed that both the SK2 channel transcript and protein were significantly downregulated in the epileptic CA1 region. We conclude that SK2 channels are down-regulated in chronic epilepsy underlying the impaired SK channel function in CA1 pyramidal cells, and a further reduction of the remaining critical mass of SK channels results in an acute network decompensation.

  20. Effects of Y211 phase contents on the critical current density Jc and microstructural analysis in YBCO bulk superconductors

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    YBCO bulk superconductors were prepared by the solid state reaction and top-seed-melt-textured growth (TSMTG) process. By using the AC susceptibility measurement, the critical transition temperature Tc of samples is 91.5 K for the highest value, and the transition width ?Tc is less than 1 K. The highest magnetization critical current densities Jc achieved 106 A/cm2 under 5 T at 10 K and 1.35?104 A/cm2 under 2 T at 70 K (H//c), respectively. The results combining the SEM observation indicate that doping of Y211 particles is more effective in improving the growth quality of melt-textured YBCO superconductor and in reducing the micro-cracks of specimens. Doping of Y2O3 powder forms the rod-shaped Y211 particles, but doping of Y211 particles directly to matrix materials forms the spherical Y211 particles mainly. Combining the microstructures with Jc measurements shows that the interfaces are most important on flux bundle pinning, in which the gradient of free energy is larger than that of other place between the Y211 particles and the Y123 matrix materials.

  1. Perceptions, attitudes, and current practices regards delirium in China: A survey of 917 critical care nurses and physicians in China.

    Science.gov (United States)

    Xing, Jinyan; Sun, Yunbo; Jie, Yaqi; Yuan, Zhiyong; Liu, Wenjuan

    2017-09-01

    The purpose of this study is to assess the knowledge, attitudes, and managements regarding delirium of intensive care nurses and physicans, and to assess the perceived barriers related to intensive care unit (ICU) delirium monitoring in China. A descriptive survey was distributed to 1156 critical care nurses and physicians from 74 tertiary and secondary hospitals across Shandong province, China. The overall response rate was 86.18% (n = 917). The majority of respondents (88%) believed that deirium was associated with prolonged mechanical ventilation, and 79.72% thought delirium was associated with prolonged length of hospitalization. Only 14.17% of respondents believed that delirium was common in the ICU setting. Only 25.62% of the respondents reported routine screening of ICU delirium, and only 15.81% utilized Confusion Assessment Method for Intensive Care Unit screening tools. "Lack of appropriate screening tools" and "time restraints" were the most common perceived barriers. 45.4% of the participants had never received any education on ICU delirium. In conclusion, most nurses and physicians consider ICU delirium to be a serious problem, but lack knowledge on delirium and monitor this condition poorly. The survey infers a disconnection between the perceived significance and current monitoring of ICU delirium. There is a critical unmet need for in-service education on ICU delirium for physicians and nurses in China.

  2. Ecopedagogy as an element of citizenship education: The dialectic of global/local spheres of citizenship and critical environmental pedagogies

    Science.gov (United States)

    Misiaszek, Greg William

    2016-09-01

    Emerging from popular education movements in Latin America, ecopedagogy is a critical environmental pedagogy which focuses on understanding the connections between social conflict and environmentally harmful acts carried out by humans. These connections are often politically hidden in education. Ecopedagogy, while being pluralistic, is in its essence defined as a critical, transformative environmental pedagogy centred on increasing social and environmental justice. Its ultimate aim is to find a sustainable balance between the conflicting goals of diverse notions of human progress and environmental wellbeing. This article is based on two comparative research projects. The first was a qualitative study on ecopedagogical models involving 31 expert ecopedagogues in Argentina, Brazil and the Appalachian region of the United States. They were asked for their perspectives on how successful ecopedagogy can be defined within the contexts in which they taught and conducted research. The second study analysed how 18 international expert scholars of citizenship and/or environmental pedagogy from six world continents regarded the ways in which citizenship intersects with environmental issues and the pedagogies of both in an increasingly globalised world, with specific focus on Global Citizenship Education. Results from the first study indicate the following two needs for effective environmental pedagogies: (1) for there to be an ecopedagogical paradigm shift in environmental teaching and research; and (2) for ecopedagogy to be an essential element of citizenship education (and vice versa). This article examines how conflicting processes of globalisation both help and hinder in achieving such a paradigm shift by decentring traditional nation-state citizenship. Results from the second study indicate how critical teaching within and between different spheres of citizenship (e.g. local, national, global, and planetary citizenship) is essential for ecopedagogy (and the

  3. Ecopedagogy as an element of citizenship education: The dialectic of global/local spheres of citizenship and critical environmental pedagogies

    Science.gov (United States)

    Misiaszek, Greg William

    2016-10-01

    Emerging from popular education movements in Latin America, ecopedagogy is a critical environmental pedagogy which focuses on understanding the connections between social conflict and environmentally harmful acts carried out by humans. These connections are often politically hidden in education. Ecopedagogy, while being pluralistic, is in its essence defined as a critical, transformative environmental pedagogy centred on increasing social and environmental justice. Its ultimate aim is to find a sustainable balance between the conflicting goals of diverse notions of human progress and environmental wellbeing. This article is based on two comparative research projects. The first was a qualitative study on ecopedagogical models involving 31 expert ecopedagogues in Argentina, Brazil and the Appalachian region of the United States. They were asked for their perspectives on how successful ecopedagogy can be defined within the contexts in which they taught and conducted research. The second study analysed how 18 international expert scholars of citizenship and/or environmental pedagogy from six world continents regarded the ways in which citizenship intersects with environmental issues and the pedagogies of both in an increasingly globalised world, with specific focus on Global Citizenship Education. Results from the first study indicate the following two needs for effective environmental pedagogies: (1) for there to be an ecopedagogical paradigm shift in environmental teaching and research; and (2) for ecopedagogy to be an essential element of citizenship education (and vice versa). This article examines how conflicting processes of globalisation both help and hinder in achieving such a paradigm shift by decentring traditional nation-state citizenship. Results from the second study indicate how critical teaching within and between different spheres of citizenship (e.g. local, national, global, and planetary citizenship) is essential for ecopedagogy (and the

  4. Fracture behaviour and its relation to critical current of silver-sheathed Ba2YCu3O(7-x) superconducting composite wires and tapes

    Science.gov (United States)

    Ochiai, Shojiro; Hayashi, Kenji; Osamura, Kozo

    1990-08-01

    Silver-sheathed Ba2YCu3O(7-x) superconducting composite wires and tapes were prepared by rolling, drawing, swaging and pressing methods. The fracture behavior and its influence on critical current at 0T at 77 K of the Ba2YCu3O(7-x) were investigated. The oxide was found to show multiple fracture under applied tensile stress, and the critical current density and tensile strength of the oxide in the rolled, swaged and pressed samples were higher than those in the drawn samples. When the working amount was high, the current density and the strength of the oxide were found to become high. Within the present conditions, there was a correlation between critical current density and cracking stress: the higher the cracking stress, the higher the critical current density became. The cracking stress of the present oxide was determined to be 50 MPa at most, being far lower than that of the Nb3Sn compound (800 to 2000 MPa). The critical current density of the rolled, swaged and pressed samples was reduced rapidly when exerted stress on the oxide exceeded the cracking stress, while the reduction in the drawn samples occurred gradually. A strong dependence of the critical current, as a function of applied stress and cracking stress of the oxide, on the measured portion due to scatter in the size of defects contained in the oxide, was found.

  5. In search of critically endangered species: the current situation of two tiny salamander species in the Neotropical mountains of Mexico.

    Directory of Open Access Journals (Sweden)

    Adriana Sandoval-Comte

    Full Text Available Worldwide, one in every three species of amphibian is endangered, 39 species have gone extinct in the last 500 years and another 130 species are suspected to have gone extinct in recent decades. Of the amphibians, salamanders have the highest portion of their species in one of the risk categories, even higher than the frogs. To date there have been few studies that have used recent field data to examine the status of populations of endangered salamanders. In this study we evaluate the current situation of two tiny salamanders, Parvimolge townsendi and Thorius pennatulus, both of which are distributed at intermediate elevations in the mountains of the northern Neotropics and are considered to be critically endangered; the first has been proposed as possibly extinct. By carrying out exhaustive surveys in both historical and potentially suitable sites for these two species, we evaluated their abundance and the characteristics of their habitats, and we estimated their potential geographic distribution. We visited 22 sites, investing 672 person-hours of sampling effort in the surveys, and found 201 P. townsendi salamanders in 11 sites and only 13 T. pennatulus salamanders in 5 sites. Both species were preferentially found in cloud forest fragments that were well conserved or only moderately transformed, and some of the salamanders were found in shade coffee plantations. The potential distribution area of both species is markedly fragmented and we estimate that it has decreased by more than 48%. The results of this study highlight the importance of carrying out exhaustive, systematic field surveys to obtain accurate information about the current situation of critically endangered species, and help us better understand the crisis that amphibians are facing worldwide.

  6. The enhancement of critical current density on the bulk of BPSCCO-system superconductor with silver additions

    Energy Technology Data Exchange (ETDEWEB)

    Engkir Sukirman; Wisnu Ari Adi; Puji Sulisworo dan W. Prasuad [Materials Science Research Center, BATAN, Serpong (Indonesia)

    1999-10-01

    The influence of silver additions on the critical current density (Jc) of BPSCCO-bulk superconductor was investigated, with the aim of getting an increase of its Jc and trying to find out a correlation of Jc and structures of BPSCCO-silver composites. The BPSCCO-system superconductors with nominal composition Bi{sub 1.84}Pb{sub 0.34}Sr{sub 2.00}Ca{sub 2.03}Cu{sub 3.06}O{sub x} (2223-phase) were synthesized by using solid state reaction method. The silver added was in the powder-AgO form varied from 0 to 30 wt % AgO. The critical current density, crystal structure, and micro-structure of BPSCCO-silver composites were characterized by means of four-point probe, x-ray diffractometer, and scanning electron microscope that is equipped with a link system energy dispersive spectrometer. It was found that silver additions to BPSCCO cause a reasonable improvement in Jc from 120 to 215 A/cm{sup 2}, and a slight increase in Tc from 92 to 108 K, and lattice parameters of the 2223-phase from a 3.811(3) to 3.820(2) A, and from c = 37.08(3) to 37.15(2) A, with the optimum value occurs at 20 wt % AgO. The AgO powders added to the BPSCCO specimens were converted to Ag{sub 2}O and metallic Ag during the annealing process at 827degC for 96 h in air. The addition of AgO to BPSCCO system does not necessarily lead to decomposition of the 2223-phase. The AgO reacts with and suppresses the 2201-phase. (author)

  7. A Critical Examination of Current On-Orbit Satellite Collision Risk Analysis Under Constraints of Public Data

    Science.gov (United States)

    Whitworth, Brandon; Moon, Mark; Pace, William; Baker, Robert

    2010-09-01

    The collision of Cosmos 2251 and Iridium 33 on 10 February 2009, made real the dangers of space operations without accurate situational awareness. A critical examination of the state of the art in collision risk assessment for on-orbit assets quickly reveals that it is inadequate to have provided satellite operators the opportunity to prevent the Cosmos-Iridium collision. Satellite operators need reliable information in a timely manner in order to take appropriate action. The shortfalls of publicly available orbit information place all spacecraft and missions at risk. The accuracy limitations of the General Perturbations(GP) catalog and orbit model(SGP-4) limit the effectiveness of current open source efforts. Beyond the accuracy limits, the relatively low frequency of updates for debris included in the catalog increases the uncertainty in time-space for inactive space objects such as Cosmos 2251. The current state of the art collision risk assessment includes advanced techniques such as expanding the GP model with covariance information which will allow uncertainty in the model to be accounted for in the on-orbit risk calculations. Covariance information can be estimated from consecutively published element sets for the same orbital object. A challenge to covariance estimation is that maneuvers or long periods of time between updates can skew the computed data. Once reliable covariance information is known and an efficient algorithm can be applied to find all of the close approaches between all cataloged objects then it is possible to estimate the collision risk for each close encounter with the tri-variate normal distribution. Unknown covariance will need to be handled in an appropriate way for a complete solution. Covariance information alone cannot solve the problem due to the relatively slow rate of update for all objects by the Space Surveillance Network(SSN) and there is no centralized source for planned and executed orbit changes for powered spacecraft. The

  8. Millisecond Coupling of Local Field Potentials to Synaptic Currents in the Awake Visual Cortex

    OpenAIRE

    Haider, Bilal; Schulz, David P.A.; Häusser, Michael; Carandini, Matteo

    2016-01-01

    Summary The cortical local field potential (LFP) is a common measure of population activity, but its relationship to synaptic activity in individual neurons is not fully established. This relationship has been typically studied during anesthesia and is obscured by shared slow fluctuations. Here, we used patch-clamp recordings in visual cortex of anesthetized and awake mice to measure intracellular activity; we then applied a simple method to reveal its coupling to the simultaneously recorded ...

  9. Millisecond Coupling of Local Field Potentials to Synaptic Currents in the Awake Visual Cortex

    OpenAIRE

    Haider, B; Schulz, D. P.; Häusser, M.; Carandini, M.

    2016-01-01

    The cortical local field potential (LFP) is a common measure of population activity, but its relationship to synaptic activity in individual neurons is not fully established. This relationship has been typically studied during anesthesia and is obscured by shared slow fluctuations. Here, we used patch-clamp recordings in visual cortex of anesthetized and awake mice to measure intracellular activity; we then applied a simple method to reveal its coupling to the simultaneously recorded LFP. LFP...

  10. local

    Directory of Open Access Journals (Sweden)

    Abílio Amiguinho

    2005-01-01

    Full Text Available The process of socio-educational territorialisation in rural contexts is the topic of this text. The theme corresponds to a challenge to address it having as main axis of discussion either the problem of social exclusion or that of local development. The reasons to locate the discussion in this last field of analysis are discussed in the first part of the text. Theoretical and political reasons are there articulated because the question is about projects whose intentions and practices call for the political both in the theoretical debate and in the choices that anticipate intervention. From research conducted for several years, I use contributions that aim at discuss and enlighten how school can be a potential locus of local development. Its identification and recognition as local institution (either because of those that work and live in it or because of those that act in the surrounding context are crucial steps to progressively constitute school as a partner for development. The promotion of the local values and roots, the reconstruction of socio-personal and local identities, the production of sociabilities and the equation and solution of shared problems were the dimensions of a socio-educative intervention, markedly globalising. This scenario, as it is argued, was also, intentionally, one of transformation and of deliberate change of school and of the administration of the educative territoires.

  11. Forced flow He vapor cooled critical current testing facility for measurements of superconductors in a wide temperature and magnetic field range

    Science.gov (United States)

    Baskys, Algirdas; Hopkins, Simon C.; Bader, Jakob; Glowacki, Bartek A.

    2016-10-01

    As superconducting materials find their way into applications, there is increasing need to verify their performance at operating conditions. Testing of critical current with respect to temperature and magnetic field is of particular importance. However, testing facilities covering a range of temperatures and magnetic fields can be costly, especially when considering the cooling power required in the cryogenic system in the temperature range below 65 K (inaccessible for LN2). Critical currents in excess of 500 A are common for commercial samples, making the testing of such samples difficult in setups cooled via a cryocooler, moreover it often does not represent the actual cooling conditions that the sample will experience in service. This work reports the design and operation of a low-cost critical current testing facility, capable of testing samples in a temperature range of 10-65 K, with magnetic field up to 1.6 T and measuring critical currents up to 900 A with variable cooling power.

  12. Localization of defects in steam generator tubes using a multi-coil eddy current probe dedicated to high speed inspection

    Energy Technology Data Exchange (ETDEWEB)

    Joubert, P.-Y.; Le Bihan, Y.; Placko, D. [Ecole Normale Superieure de Cachan (France). Laboratoire d' Electricite Signaux et Robotique

    2002-07-01

    Steam generator (SG) tubing of pressurized water reactor in nuclear plants must be rapidly and accurately checked in order to detect defects in their early stages. In this paper, the authors present a multi-coil eddy current (EC) probe allowing both high speed inspection and circumferential localization of defects in the tube wall. A method of multi-coil EC signal processing, based on a continuous wavelet transform combined with a maximum likelihood diagnosis, is elaborated in order to enhance the detection performances and to provide automatic localization of defects. The inspection of SG tube samples shows good localization performances for defects as small as 10% deep, 15 mm long and 100 {mu}m wide outer diameter notches, of both circumferential and axial orientations. (author)

  13. Kinetics of local "magnetic" moment and non-stationary spin-polarized current in the single impurity Anderson-model

    Science.gov (United States)

    Maslova, N. S.; Mantsevich, V. N.; Arseyev, P. I.

    2017-02-01

    We perform theoretical investigation of the localized state dynamics in the presence of interaction with the reservoir and Coulomb correlations. We analyze kinetic equations for electron occupation numbers with different spins taking into account high order correlation functions for the localized electrons. We reveal that in the stationary state electron occupation numbers with the opposite spins always have the same value - the stationary state is a "paramagnetic" one. "Magnetic" properties can appear only in the non-stationary characteristics of the single-impurity Anderson model and in the dynamics of the localized electrons second order correlation functions. We found, that for deep energy levels and strong Coulomb correlations, relaxation time for initial "magnetic" state can be several orders larger than for "paramagnetic" one. So, long-living "magnetic" moment can exist in the system. We also found non-stationary spin polarized currents flowing in opposite directions for the different spins in the particular time interval.

  14. Presentation of Local and International Culture in Current International English-Language Teaching Textbooks

    Science.gov (United States)

    Shin, Jeeyoung; Eslami, Zohreh R.; Chen, Wen-Chun

    2011-01-01

    The place of culture in teaching English as an international language (EIL) is a complex issue, given the diversity of contexts in which English is currently being used globally. Building on a sociocultural perspective that language use is open to negotiation and is context-dependent, this paper argues that the design and content of…

  15. Value and Efficacy of Transcranial Direct Current Stimulation in the Cognitive Rehabilitation: A Critical Review Since 2000.

    Science.gov (United States)

    Cappon, Davide; Jahanshahi, Marjan; Bisiacchi, Patrizia

    2016-01-01

    Non-invasive brain stimulation techniques, including transcranial direct current stimulation (t-DCS) have been used in the rehabilitation of cognitive function in a spectrum of neurological disorders. The present review outlines methodological communalities and differences of t-DCS procedures in neurocognitive rehabilitation. We consider the efficacy of tDCS for the management of specific cognitive deficits in four main neurological disorders by providing a critical analysis of recent studies that have used t-DCS to improve cognition in patients with Parkinson's Disease, Alzheimer's Disease, Hemi-spatial Neglect, and Aphasia. The evidence from this innovative approach to cognitive rehabilitation suggests that tDCS can influence cognition. However, the results show a high variability between studies both in terms of the methodological approach adopted and the cognitive functions targeted. The review also focuses both on methodological issues such as technical aspects of the stimulation (electrode position and dimension; current intensity; duration of protocol) and on the inclusion of appropriate assessment tools for cognition. A further aspect considered is the optimal timing for administration of tDCS: before, during or after cognitive rehabilitation. We conclude that more studies using common methodology are needed to gain a better understanding of the efficacy of tDCS as a new tool for rehabilitation of cognitive disorders in a range of neurological disorders.

  16. Evaluation of uncertainty in the inductive measurement of critical current densities of superconducting films using third-harmonic voltages

    Science.gov (United States)

    Yamasaki, H.; Mawatari, Y.; Nakagawa, Y.; Yamada, H.

    2012-10-01

    Several techniques can be used for inductive measurement of the critical current density Jc of large-area superconducting thin films used in microwave devices and fault-current limiters. The most popular of these methods employs the third-harmonic voltages V3. We have proposed a standard method using V3 for determining Jc under a criterion of electric field E. Here, the uncertainty in the standard method is evaluated. Since the measured Jc is directly proportional to the magnetic field at the upper surface of the superconducting film, the most significant systematic effect is the deviation of the coil-to-film distance Z1 from the prescribed value. The principal origins of this deviation of Z1 are (1) inadequate pressing of the coil onto the film and (2) ice layers occasionally forming between the coil and the protective polyimide film. If these effects are eliminated, uncertainty of Jc originates mainly from (a) uncertainty of the experimental coil coefficient k', which is dominated by uncertainty of the transport Jc, and (b) underestimation of the induced electric field E when using a simple Bean model. For a typical DyBa2Cu3O7 film specimen, the relative combined standard uncertainty in the standard method was evaluated as ˜5%. The effect of the film edge on Jc measurements is also described.

  17. Value and efficacy of transcranial direct current stimulation in the cognitive rehabilitation : A critical review since 2000.

    Directory of Open Access Journals (Sweden)

    Davide eCappon

    2016-04-01

    Full Text Available Non-invasive brain stimulation techniques, including transcranial direct current stimulation (t-DCS have been used in the rehabilitation of cognitive function in a spectrum of neurological disorders. The present review outlines methodological communalities and differences of t-DCS procedures in neurocognitive rehabilitation. We consider the efficacy of tDCS for the management of specific cognitive deficits in four main neurological disorders by providing a critical analysis of recent studies that have used t-DCS to improve cognition in patients with Parkinson’s Disease, Alzheimer’s Disease, Hemi-spatial Neglect and Aphasia. The evidence from this innovative approach to cognitive rehabilitation suggests that tDCS can influence cognition. However, the results show a high variability between studies both in terms of the methodological approach adopted and the cognitive functions targeted. The review also focuses both on methodological issues such as technical aspects of the stimulation (electrode position and dimension; current intensity; duration of protocol and on the inclusion of appropriate assessment tools for cognition. A further aspect considered is the optimal timing for administration of tDCS: before, during or after cognitive rehabilitation. We conclude that more studies using common methodology are needed to gain a better understanding of the efficacy of tDCS as a new tool for rehabilitation of cognitive disorders in a range of neurological disorders.

  18. International round robin test of the retained critical current after double bending at room temperature of Ag-sheathed Bi-2223 superconducting wires

    Science.gov (United States)

    Yamada, Y.; Nishijima, G.; Osamura, K.; Shin, H. S.; Goldacker, W.; Breschi, M.; Ribani, P.

    2016-02-01

    An international round robin test was carried out in order to establish a test method for retained critical current after double bending at room temperature of Ag-sheathed Bi-2223 superconducting wires. Tests for commercial Bi-2223 tape were conducted by six laboratories using the same guidelines. The standard uncertainties (SUs) of measurands were evaluated for these four quantities: I C0, I C/I C080, I C/I C060, I C/I C050, where, I C0 is initial critical current and I C /I C0XX is critical current after XX mm bending. Using an F test to determine where the most scatter was generated in the test results it was found that the greatest scatter in the normalized critical current measurements came from inter-laboratory scatter. In a type-B uncertainty evaluation, the major contribution was from the bending diameter and measuring temperature. The relative SU tended to increase as the bending diameter decreased. A specific mandrel diameter corresponding to a retained critical current of 95% could be determined with a relative SU of 1.3%. In order to reduce the overall scatter, the temperature difference between the critical current measurements before and after bending should be small.

  19. Quasi-1D van der Waals materials as high current-density local interconnects (Conference Presentation)

    Science.gov (United States)

    Stolyarov, Maxim; Aytan, Ece; Bloodgood, Matthew; Salguero, Tina T.; Balandin, Alexander A.

    2016-09-01

    The continuous downscaling of interconnect dimensions in combination with the introduction of low-k dielectrics has increased the number of heat dissipation, integration and reliability challenges in modern electronics. As a result, there is a strong need for new materials that have high current-carrying capacity for applications as nanoscale interconnects. In this presentation, we show that quasi-one-dimensional (1D) van der Waals metals such as TaSe3 have excellent breakdown current density exceeding that of 5 MA/cm2. This value is above that currently achievable in conventional copper or aluminum wires. The quasi-1D van der Waals materials are characterized by strong bonds along one dimension and weak van der Waals bonds along two other dimensions. The material for this study was grown by the chemical vapor transport (CVT) method. Both mechanical and chemical exfoliation methods were used to fabricate nanowires with lateral dimensions below 100 nm. The dimensions of the quasi-1D nanowires were verified with scanning electron microscopy (SEM) and atomic force microscopy (AFM). The metal (Ti/Au) contacts for the electrical characterization were deposited using electron beam evaporation (EBE). The measurements were conducted on a number of prototype interconnects with multiple electric contacts to ensure reproducibility. The obtained results suggest that quasi-1D van der Waals metals present a feasible alternative to conventional copper interconnects in terms of the current-carrying capacity and the breakdown current-density. This work was supported, in part, by the SRC and DARPA through STARnet Center for Function Accelerated nanoMaterial Engineering (FAME).

  20. Long RE123 coated conductors with high critical current over 500 A/cm by IBAD/PLD technique

    Energy Technology Data Exchange (ETDEWEB)

    Kakimoto, K., E-mail: kkakimoto@fujikura.co.jp [Fujikura Ltd., 1440, Mutsuzaki, Sakura, Chiba 285-8550 (Japan); Igarashi, M.; Hanyu, S.; Sutoh, Y.; Takemoto, T.; Hayashida, T.; Hanada, Y.; Nakamura, N.; Kikutake, R.; Kutami, H.; Iijima, Y.; Saitoh, T. [Fujikura Ltd., 1440, Mutsuzaki, Sakura, Chiba 285-8550 (Japan)

    2011-11-15

    We have developed long RE123 coated conductors with large current capacity by IBAD and HW-PLD technique. We could fabricate an 8 m-long Gd123 coated wire with the I{sub c} of over 900 A/cm-w at 77 K, 0 T. We set the new world record of I{sub c} x L value as 374535 A m (= 609 A x 615 m). We have developed long RE{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-X} (RE123) coated conductors with large current capacity by the ion beam assisted deposition (IBAD) and the pulsed laser deposition using hot wall heating (HW-PLD) technique. As a result, we could fabricate an 8 m-long Gd{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-X} (Gd123) coated wire with the minimum and maximum critical current (I{sub c}) of 951 A/cm-w and 1003 A/cm-w at 77 K, 0 T, respectively, measured in 0.7 m-long sections by the standard 4-probe technique. Furthermore, we succeeded in preparation of over 600 m-long Gd123 coated wire with the uniform I{sub c} distribution over 600 A/cm-w. It had average, maximum and minimum I{sub c} of 665, 698, 609 A/cm-w, respectively. The n-values of the sample showed the maximum I{sub c} and minimum I{sub c} were 40 and 36, respectively. As a result, we set the new world record of I{sub c} x L value as 374535 A m (= 609 A x 615 m). The in-field performance of this long wire was quite high as well; the minimum I{sub c} exceeded 50 A/cm-w at 77 K, 3 T.

  1. Strained local and state government finances among current realities that threaten public hospitals' profitability.

    Science.gov (United States)

    Kane, Nancy M; Singer, Sara J; Clark, Jonathan R; Eeckloo, Kristof; Valentine, Melissa

    2012-08-01

    This study demonstrates that some safety-net hospitals--those that provide a large share of the care to low-income, uninsured, and Medicaid populations--survived and even thrived before the recent recession. We analyzed the financial performance and governance of 150 hospitals during 2003-07. We found, counterintuitively, that those directly governed by elected officials and in highly competitive markets were more profitable than other safety-net hospitals. They were financially healthy primarily because they obtained subsidies from state and local governments, such as property tax transfers or supplemental Medicaid payments, including disproportionate share payments. However, safety-net hospitals now face a new market reality. The economic downturn, slow recovery, and politics of deficit reduction have eroded the ability of local governments to support the safety net. Many safety-net hospitals have not focused on effective management, cost control, quality improvement, or services that attract insured patients. As a result, and coupled with new uncertainties regarding Medicaid expansion stemming from the recent Supreme Court decision on the Affordable Care Act, many are likely to face increasing financial and competitive pressures that may threaten their survival.

  2. Relative roles of local disturbance, current climate and palaeoclimate in determining phylogenetic and functional diversity in Chinese forests

    Directory of Open Access Journals (Sweden)

    G. Feng

    2013-09-01

    Full Text Available The main processes underlying the generation and maintenance of biodiversity include both local factors such as competition and abiotic filtering and regional forces such as palaeoclimate, speciation and dispersal. While the effects of regional and local drivers on species diversity are increasingly studied, their relative importance for other aspects of diversity, notably phylogenetic and functional diversity is so far little studied. Here, we link data from large Chinese forest plots to data on current and Last Glacial Maximum (LGM climate as well as local disturbance regimes to study their relative roles in determining woody plant phylogenetic and functional diversity in this important hotspot for woody plant diversity. Local disturbance was the best predictor of functional diversity as represented by maximum canopy height (Hmax, probably reflecting the dominant role of competition for light in determining the forest Hmax structure. In contrast, the LGM-present anomaly in temperature was the factor with the strongest explanatory power for phylogenetic diversity, with modern climate also important. Hence, local contemporary and regional historical factors have highly contrasting importance for the geographic patterns of the functional and phylogenetic aspects of Chinese forest woody plant diversity. Importantly, contemporary factors are of overriding importance for functional diversity, while palaeoclimate has left a strong signature in the phylogenetic diversity patterns.

  3. Global forces and local currents in Argentina's science policy crossroads: restricted access or open knowledge

    Directory of Open Access Journals (Sweden)

    Horacio Javier Etchichury

    2014-11-01

    Full Text Available The article describes the tensions between two competing approaches to scientific policy in Argentina. The traditional vision favors autonomous research. The neoliberal conception fosters the link between science and markets. In the past few years, a neodevelopmentalist current also tries to stress relevance of scientific research. Finally, the article describes how the Open Access movement has entered the debate. The World Bank intervention and the human rights dimension of the question are discussed in depth. The article introduces the notion of open knowledge as a guiding criterion to design a human-rights based scientific policy.

  4. Local membrane deformations activate Ca2+-dependent K+ and anionic currents in intact human red blood cells.

    Directory of Open Access Journals (Sweden)

    Agnieszka Dyrda

    Full Text Available BACKGROUND: The mechanical, rheological and shape properties of red blood cells are determined by their cortical cytoskeleton, evolutionarily optimized to provide the dynamic deformability required for flow through capillaries much narrower than the cell's diameter. The shear stress induced by such flow, as well as the local membrane deformations generated in certain pathological conditions, such as sickle cell anemia, have been shown to increase membrane permeability, based largely on experimentation with red cell suspensions. We attempted here the first measurements of membrane currents activated by a local and controlled membrane deformation in single red blood cells under on-cell patch clamp to define the nature of the stretch-activated currents. METHODOLOGY/PRINCIPAL FINDINGS: The cell-attached configuration of the patch-clamp technique was used to allow recordings of single channel activity in intact red blood cells. Gigaohm seal formation was obtained with and without membrane deformation. Deformation was induced by the application of a negative pressure pulse of 10 mmHg for less than 5 s. Currents were only detected when the membrane was seen domed under negative pressure within the patch-pipette. K(+ and Cl(- currents were strictly dependent on the presence of Ca(2+. The Ca(2+-dependent currents were transient, with typical decay half-times of about 5-10 min, suggesting the spontaneous inactivation of a stretch-activated Ca(2+ permeability (PCa. These results indicate that local membrane deformations can transiently activate a Ca(2+ permeability pathway leading to increased [Ca(2+](i, secondary activation of Ca(2+-sensitive K(+ channels (Gardos channel, IK1, KCa3.1, and hyperpolarization-induced anion currents. CONCLUSIONS/SIGNIFICANCE: The stretch-activated transient PCa observed here under local membrane deformation is a likely contributor to the Ca(2+-mediated effects observed during the normal aging process of red blood cells, and

  5. Suppressing local hot spots due to eddy currents in magnetic coil systems

    Science.gov (United States)

    Yao, Zhen; Shojinaga, Aaron; Wu, Yong; Shvartsman, Shmaryu; Eagan, Timothy; Chmielewski, Thomas; Brown, Robert

    2011-03-01

    A particular goal in magnetic field applications is to avoid eddy current heating in coils and shields. It is important, in MRI, for example, to avoid hot spots near the patient to be imaged as well as in the vicinity of soldering joints. We develop effective analytical formulas for the eddy current behavior of sources close to surrounding conductors, we verify these via numerical simulations, and we make successful comparisons to corresponding experimental temperature distributions. Optimized patterns of incisions made in the conductors are discovered for addressing particularly troublesome heating locations. The criteria include the need to minimize the number and length of the cuts. Theory and experiment are in agreement on the efficacy of this method for reducing steady-state temperatures. An example of results in the practical design of commercial coils and shields is that a single cut parallel to the long edge of rectangular conductors reduces the temperatures much more than making multiple cuts parallel to the short edge. Supported by Ohio Third Frontier Program

  6. Development of inherent technologies for advanced PWR core - A study on the current status and the construction feasibility of critical facilities

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Won Sik; Yang, Hyun Seok [Chosun University, Kwangju (Korea); Kim, Chang Hyo; Shim, Hyung Jin [Seoul National University, Seoul (Korea)

    1999-03-01

    The objective of this study is to examine the appropriateness of constructing critical facilities in our country and to decide a course of constructing them if necessary by surveying the status and utilization of foreign facilities and by investigating the demand for domestic facilities. We investigated the status and the utilization of foreign critical facilities through literature survey and personal visitation. In our judgement, critical facilities are necessary for developing the advanced reactors and fuels which are being studied as parts of the Nuclear R and D Program by MOST. Considering the construction cost and the current state of domestic economy, however, it is unjustifiable to build three different types of critical facilities (the light water, the heavy water, and the fast critical facility). It appears to be reasonable to build a light water critical, considering the construction cost, degree of utilization, and other constraints. (author). 89 refs., 134 figs., 64 tabs.

  7. Universal correlation between critical current density and normal-state resistivity in porous YBa{sub 2}Cu{sub 3}O{sub 7-x} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bartolome, E [Instituto de Ciencia de Materiales de Barcelona-CSIC, Campus UAB, 08193-Bellaterra (Spain); Goemory, F [Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska Cesta 9, 84239 Bratislava (Slovakia); Granados, X [Instituto de Ciencia de Materiales de Barcelona-CSIC, Campus UAB, 08193-Bellaterra (Spain); Puig, T [Instituto de Ciencia de Materiales de Barcelona-CSIC, Campus UAB, 08193-Bellaterra (Spain); Obradors, X [Instituto de Ciencia de Materiales de Barcelona-CSIC, Campus UAB, 08193-Bellaterra (Spain)

    2007-10-15

    We have simulated the inductive critical currents and transport currents in the dissipative state of superconducting thin films with an increasing amount of porosity by using a Bean model-based programme (Trazacorrientes{sup (registered))) and finite-element software. Simulations allowed us to find a quantitative, quasi-universal relationship between the overall critical current density and the normal-state resistivity via the sample porosity. This theoretical curve served to fit the experimental data found for a large number ({approx}150) of epitaxial YBa{sub 2}Cu{sub 3}O{sub 7-x} thin films grown by the trifluoracetate route.

  8. Current signatures and search for Pop. III stars in the Local Universe

    CERN Document Server

    Komiya, Yutaka; Fujimoto, Masayuki

    2013-01-01

    Recent numerical studies argue that low-mass stars can be formed even at zero-metallicity environment. These low-mass Population III(Pop.~III) stars are thought to be still shining and able to be observed in the Local Universe. Most low-mass Pop.~III stars are thought to be formed as secondary companions in binary systems. They can be escaped from their host mini-halos when their primary companions explode as supernovae. In this paper, we estimate the escape probability of the low-mass Pop.~III stars from their host mini-halos. We find that $\\sim 100$ Pop.~III stars are expected. We also compute spatial distribution of these escaped Pop.~III survivors by means of the semi-analytic hierarchical chemical evolution model. Typically, they are distributed around $\\sim 2$Mpc away from the Milky Way but 5 -- $35\\%$ of the escaped stars fall into the Milky Way halo. These escaped Pop.~III stars are possibly detected by very large scaled surveys being planned.

  9. The intermediates take it all: asymptotics of higher criticism statistics and a powerful alternative based on equal local levels.

    Science.gov (United States)

    Gontscharuk, Veronika; Landwehr, Sandra; Finner, Helmut

    2015-01-01

    The higher criticism (HC) statistic, which can be seen as a normalized version of the famous Kolmogorov-Smirnov statistic, has a long history, dating back to the mid seventies. Originally, HC statistics were used in connection with goodness of fit (GOF) tests but they recently gained some attention in the context of testing the global null hypothesis in high dimensional data. The continuing interest for HC seems to be inspired by a series of nice asymptotic properties related to this statistic. For example, unlike Kolmogorov-Smirnov tests, GOF tests based on the HC statistic are known to be asymptotically sensitive in the moderate tails, hence it is favorably applied for detecting the presence of signals in sparse mixture models. However, some questions around the asymptotic behavior of the HC statistic are still open. We focus on two of them, namely, why a specific intermediate range is crucial for GOF tests based on the HC statistic and why the convergence of the HC distribution to the limiting one is extremely slow. Moreover, the inconsistency in the asymptotic and finite behavior of the HC statistic prompts us to provide a new HC test that has better finite properties than the original HC test while showing the same asymptotics. This test is motivated by the asymptotic behavior of the so-called local levels related to the original HC test. By means of numerical calculations and simulations we show that the new HC test is typically more powerful than the original HC test in normal mixture models.

  10. Critical behaviour of ($2+1$)-dimensional QED: $1/N_f$-corrections in an arbitrary non-local gauge

    CERN Document Server

    Kotikov, A V

    2016-01-01

    Dynamical chiral symmetry breaking (D$\\chi$SB) is studied within ($2+1$)-dimensional QED with $N$ four-component fermions. The leading and next-to-leading orders of the $1/N$ expansion are computed exactly. The analysis is carried out in an arbitrary non-local gauge. Resumming the wave-function renormalization constant at the level of the gap equation yields a strong suppression of the gauge dependence of the critical fermion flavour number, $N_c(\\xi)$ where $\\xi$ is the gauge fixing parameter, which is such that D$\\chi$SB takes place for $N

  11. Sintering process and critical current density of low activation Mg11B2 superconductors from low temperature to high temperature

    Science.gov (United States)

    Cheng, Fang; Liu, Yongchang; Ma, Zongqing; Shahriar Al Hossain, Md; Somer, M.

    2016-08-01

    As the "low activation" superconductor, Mg11B2 has a potential application in superconducting coils for fusion reactor. In present work, the sintering process and critical current density of low activation Mg11B2 superconductors were systemically studied from low temperature to high temperature. It was found that the Jc and Hirr values of Mg11B2 bulks in present work are both obviously higher than that of those samples prepared in previous studies. Furthermore, the low-temperature sintered samples exhibit better Jc performance at high fields than the high-temperature sintered samples, due to strong grain boundaries pinning. On the other hand, the high-temperature sintered samples have higher Jc at low fields compared to low-temperature sintered samples, mainly owing to their better crystallinity and grain connectivity. The highest Jc value (2.20 ×105 A cm-2 at 20 K, self-field) is obtained in the Mg11B2 sample sintered at 850 °C for 45 min.

  12. Effect of Nano-SiC and Nano-Si Doping on Critical Current Density of MgB2

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The discovery of superconductivity in magnesium diboride (MgB2) has opened up a new field in materials science research. It offers a possibility of a new class of high performance superconducting materials for practical applications becauseigher Tc (Tc=39 K) compared with Nb3Sn and Nb-Ti alloys (two or four times that of Nb3Sn and Nb-Ti alloys). However, the weak flux pinning in the magneticfield remains a major challenge. This paper reports the most interesting results on nanomaterial (SiC and Si) doping in magnesium diboride. The high densityof nano-scale defects introduced by doping is responsible for the enhanced pinning. The fabrication method, critical current density, microstructures, flux pinning and cost for magnesium diboride bulks, wires and tapes are also discussed. It is believed that high performance SiC doped MgB2 will have a great potential for many practical applications at 5 K to 25 K up to 5 T.

  13. Multi-criteria decision making to support waste management: A critical review of current practices and methods.

    Science.gov (United States)

    Goulart Coelho, Lineker M; Lange, Liséte C; Coelho, Hosmanny Mg

    2017-01-01

    Solid waste management is a complex domain involving the interaction of several dimensions; thus, its analysis and control impose continuous challenges for decision makers. In this context, multi-criteria decision-making models have become important and convenient supporting tools for solid waste management because they can handle problems involving multiple dimensions and conflicting criteria. However, the selection of the multi-criteria decision-making method is a hard task since there are several multi-criteria decision-making approaches, each one with a large number of variants whose applicability depends on information availability and the aim of the study. Therefore, to support researchers and decision makers, the objectives of this article are to present a literature review of multi-criteria decision-making applications used in solid waste management, offer a critical assessment of the current practices, and provide suggestions for future works. A brief review of fundamental concepts on this topic is first provided, followed by the analysis of 260 articles related to the application of multi-criteria decision making in solid waste management. These studies were investigated in terms of the methodology, including specific steps such as normalisation, weighting, and sensitivity analysis. In addition, information related to waste type, the study objective, and aspects considered was recorded. From the articles analysed it is noted that studies using multi-criteria decision making in solid waste management are predominantly addressed to problems related to municipal solid waste involving facility location or management strategy.

  14. The synthesis of lamellar nano MgB2 grains with nanoimpurities, flux pinning centers and their significantly improved critical current density.

    Science.gov (United States)

    Ma, Zongqing; Liu, Yongchang; Cai, Qi

    2012-03-21

    MgB(2) superconductors with unique microstructures were rapidly fabricated at low temperatures, and exhibited significantly improved critical current density (J(c)). According to the microstructure observations, the prepared samples consisted of lamellar nano MgB(2) grains with many embedded nanoimpurities (about 10 nm). The formation of these lamellar nano MgB(2) grains is associated with the presence of a local Mg-Cu liquid at sintering temperatures as low as 575 °C. The ball milling treatment of the original powders also plays a positive role in the growth of lamellar grains. Based on an analysis of the relationship between resistivity and temperature, the lamellar nano MgB(2) grains in the prepared sample possess better grain connectivity than the typical morphology of MgB(2) samples prepared by traditional high-temperature sintering. Furthermore, the presence of many nano MgB(2) grain boundaries and nano impurities in the prepared sample can obviously increase the flux pinning centers in accordance with the analysis of flux pinning behavior. Both factors mentioned above contribute to the significant improvement in J(c) from low field to relative high field. The method developed in the present work is an effective and low-cost way to further enhance J(c) in MgB(2) superconductors across a wide range of applied magnetic fields without using expensive nanometer-sized dopants.

  15. Local closed world reasoning: a personal view on current status and trends

    Institute of Scientific and Technical Information of China (English)

    Jeff Z. PAN; Yuan REN

    2012-01-01

    1 Introduction In computer science and artificial intelligence,an ontology is a model of (some aspect of) the world that introduces the vocabulary of a particular domain,and specifies the meaning (semantics) of terms.Today's ontologies are based on the description logics (DLs).With the help of DL reasoners,implicit knowledge can be inferred from explicit knowledge in an ontology.Different from the relational database or logic programming,ontologies impose the open world assumption (OWA) instead of the closed world assumption (CWA).In CWA,a proposition will be regarded as false,if there is no evidence for it being true.While in OWA,a proposition will be regarded as false if and only if there is clear.evidence for it being false.These two assumptions seem to contradict with each other.However,in real world applications,it is usually desired to combine OWA and CWA.For example,a restaurant should not close the class ‘Vegetarian Customer’ because whether a new customer is vegetarian or not is unknown to the restaurant unless explicitly asserted by the customer.Nevertheless,it can close the class ‘Vegetarian Food Menu’ because it has the complete knowledge about its own menus.This raises the challenge of doing local closed world reasoning (LCWR) with ontologies.In the following sections of this extended abstract,we review the state of the art regarding this topic.We also propose several emerging topics in this research area and discuss possible technical directions.

  16. Pharmacological treatment of schizophrenia: a critical review of the pharmacology and clinical effects of current and future therapeutic agents.

    Science.gov (United States)

    Miyamoto, S; Miyake, N; Jarskog, L F; Fleischhacker, W W; Lieberman, J A

    2012-12-01

    of comparable or superior efficacy and side-effect profiles to existing APDs; (2) development of novel (and presumably non-D(2)) mechanism APDs; (3) development of compounds to be used as adjuncts to APDs to augment efficacy by targeting specific symptom dimensions of schizophrenia and particularly those not responsive to traditional APD treatment. In addition, efforts are being made to determine if the products of susceptibility genes in schizophrenia, identified by genetic linkage and association studies, may be viable targets for drug development. Finally, a focus on early detection and early intervention aimed at halting or reversing progressive pathophysiological processes in schizophrenia has gained great influence. This has encouraged future drug development and therapeutic strategies that are neuroprotective. This article provides an update and critical review of the pharmacology and clinical profiles of current APDs and drugs acting on novel targets with potential to be therapeutic agents in the future.

  17. Extremely Severe Space Weather and Geomagnetically Induced Currents in Regions with Locally Heterogeneous Ground Resistivity

    Science.gov (United States)

    Fujita, Shigeru; Kataoka, Ryuho; Pulkkinen, Antti; Watari, Shinichi

    2016-01-01

    Large geomagnetically induced currents (GICs) triggered by extreme space weather events are now regarded as one of the serious natural threats to the modern electrified society. The risk is described in detail in High-Impact, Low-Frequency Event Risk, A Jointly-Commissioned Summary Report of the North American Electric Reliability Corporation and the US Department of Energy's November 2009 Workshop, June 2010. For example, the March 13-14,1989 storm caused a large-scale blackout affecting about 6 million people in Quebec, Canada, and resulting in substantial economic losses in Canada and the USA (Bolduc 2002). Therefore, European and North American nations have invested in GIC research such as the Solar Shield project in the USA (Pulkkinen et al. 2009, 2015a). In 2015, the Japanese government (Ministry of Economy, Trade and Industry, METI) acknowledged the importance of GIC research in Japan. After reviewing the serious damages caused by the 2011 Tohoku-Oki earthquake, METI recognized the potential risk to the electric power grid posed by extreme space weather. During extreme events, GICs can be concerning even in mid- and low-latitude countries and have become a global issue.

  18. Relationship of Clinical and Pathologic Nodal Staging in Locally Advanced Breast Cancer: Current Controversies in Daily Practice?

    Science.gov (United States)

    De Felice, Francesca; Musio, Daniela; Bulzonetti, Nadia; Raffetto, Nicola; Tombolini, Vincenzo

    2014-01-01

    Systemic neo-adjuvant therapy plays a primary role in the management of locally advanced breast cancer. Without having any negative effect in overall survival, induction chemotherapy potentially assures a surgery approach in unresectable disease or a conservative treatment in technically resectable disease and acts on a well-vascularized tumor bed, without the modifications induced by surgery. A specific issue has a central function in the neo-adjuvant setting: lymph nodes status. It still represents one of the strongest predictors of long-term prognosis in breast cancer. The discussion of regional radiation therapy should be a matter of debate, especially in a pathological complete response. Currently, the indication for radiotherapy is based on the clinical stage before the surgery, even for the irradiation of the loco-regional lymph nodes. Regardless of pathological down-staging, radiation therapy is accepted as standard adjuvant treatment in locally advanced breast cancer. PMID:25247013

  19. Relativistic electron's butterfly pitch angle distribution modulated by localized background magnetic field perturbation driven by hot ring current ions

    Science.gov (United States)

    Xiong, Ying; Chen, Lunjin; Xie, Lun; Fu, Suiyan; Xia, Zhiyang; Pu, Zuyin

    2017-05-01

    Dayside modulated relativistic electron's butterfly pitch angle distributions (PADs) from ˜200 keV to 2.6 MeV were observed by Van Allen Probe B at L = 5.3 on 15 November 2013. They were associated with localized magnetic dip driven by hot ring current ion (60-100 keV proton and 60-200 keV helium and oxygen) injections. We reproduce the electron's butterfly PADs at satellite's location using test particle simulation. The simulation results illustrate that a negative radial flux gradient contributes primarily to the formation of the modulated electron's butterfly PADs through inward transport due to the inductive electric field, while deceleration due to the inductive electric field and pitch angle change also makes in part contribution. We suggest that localized magnetic field perturbation, which is a frequent phenomenon in the magnetosphere during magnetic disturbances, is of great importance for creating electron's butterfly PADs in the Earth's radiation belts.

  20. Local membrane deformations activate Ca2+-dependent K+ and anionic currents in intact human red blood cells

    DEFF Research Database (Denmark)

    Dyrda, Agnieszka; Cytlak, Urszula; Ciuraszkiewicz, Anna

    2010-01-01

    by such flow, as well as the local membrane deformations generated in certain pathological conditions, such as sickle cell anemia, have been shown to increase membrane permeability, based largely on experimentation with red cell suspensions. We attempted here the first measurements of membrane currents......-activated transient PCa observed here under local membrane deformation is a likely contributor to the Ca(2+)-mediated effects observed during the normal aging process of red blood cells, and to the increased Ca(2+) content of red cells in certain hereditary anemias such as thalassemia and sickle cell anemia.......BACKGROUND: The mechanical, rheological and shape properties of red blood cells are determined by their cortical cytoskeleton, evolutionarily optimized to provide the dynamic deformability required for flow through capillaries much narrower than the cell's diameter. The shear stress induced...

  1. Enhancement of critical current density in fast neutron irradiated melt-textured YBa[sub 2]Cu[sub 3]O[sub 7-x

    Energy Technology Data Exchange (ETDEWEB)

    Puzniak, R.; Wisniewski, A.; Baran, M.; Szymczak, H. (Polska Akademia Nauk, Warsaw (Poland). Inst. Fizyki); Zhang Pingxiang; Wang Jingrong; Zhou Lian (Northwest Inst. for Nonferrous Metal Research, Baoji, SN (China)); Pytel, K.; Pytel, B. (Institute of Atomic Energy, Otwock-Swierk (Poland))

    1993-01-01

    The critical current density in melt-textured samples of YBa[sub 2]Cu[sub 3]O[sub 7]-x obtained by the powder melting process was determined from magnetization measurements. A linear dependence between the width of the hysteresis loop and sample size was observed for both unirradiated and irradiated samples. This indicates that the critical current is circulating through the whole sample and is not disconnected by weak links, even when a magnetic field is applied in the irradiated sample. After fast neutron irradiation with fluences form 5 x 10[sup 16] to 6 x 10[sup 17] n cm[sup -2] (E > 0.5 MeV), significant enhancement of the critical current density, j[sub c], was observed. Critical current density, determined from magnetization measurements, for magnetic field perpendicular to the a-b plane j[sub c][sup ab], reaches [approx] 10[sup 5] A cm[sup -2] at 77 K in 1 T. For H parallel to the a-b plane, j[sub c][sup c] along the c-axis reaches 5 x 10[sup 3] A cm[sup -2]. An increase in the anisotropy of the critical current was observed after fast neutron irradiation in the temperature range 60-80 K. (Author).

  2. High, magnetic-field-insensitive transport critical currents in unoriented polycrystalline thin films of Tl 2CaBa 2Cu 2O y

    Science.gov (United States)

    Kwak, J. F.; Venturini, E. L.; Baughman, R. J.; Morosin, B.; Ginley, D. S.

    1988-08-01

    We report critical current measurements for unoriented polycrystalline films of Tl 2CaBa 2Cu 2O y. At 77 K these films show critical current densities ranging from 10 000 to 110 000 A/cm 2, with a median value of 50 000 A/cm 2. Moreover, the best films' critical currents at 77 K drop less than 50% in an applied magnetic field of 1 T, and less than a factor of 20 at 6 T. At 4 K, critical current densities over 10 6A/cm 2 with less than 15% drop at 6 T have been obtained. The zero-field temperature dependence of the critical current from 4 to 95 K is well described as quadratic. High-field magnetization loops on the films at 76 K show a striking collapse in hysteresis below 0.6 T. Our results indicate that, although the grains in these films are Josephson-coupled, the strength of the coupling is greatly improved over other high- Tc granular systems.

  3. Prosumer-Citizenship and the Local: A Critical Case Study of Consumer Reviewing on Yelp.com

    Science.gov (United States)

    Kuehn, Kathleen M.

    2011-01-01

    Over the past few years, content developers searching for new markets have found a potentially lucrative consumer base in local and location-based services as new media platforms have begun to "expand" their focus to hyper-local place-based communities. This shift to "local 2.0" has given birth to "local listing sites," an emerging social medium…

  4. Prosumer-Citizenship and the Local: A Critical Case Study of Consumer Reviewing on Yelp.com

    Science.gov (United States)

    Kuehn, Kathleen M.

    2011-01-01

    Over the past few years, content developers searching for new markets have found a potentially lucrative consumer base in local and location-based services as new media platforms have begun to "expand" their focus to hyper-local place-based communities. This shift to "local 2.0" has given birth to "local listing sites," an emerging social medium…

  5. State and local levels of preparedness for terrorist incidents : the current and sobering U.S. picture

    Energy Technology Data Exchange (ETDEWEB)

    Paulson, G. [New Jersey Univ. of Medicine and Dentistry, New Brunswick, NJ (United States). School of Public Health; Scott, C.M.; Scott-Dimenna, D. [Rutgers Univ., New Brunswick, NJ (United States)

    2005-07-01

    An increasing number of professional organizations and foundations have surveyed components of the United States readiness programs concerning preparedness for terrorist attacks. This paper reviews the results of research conducted in 2002 and compares them with subsequent studies, demonstrating a gap between desired and current states of readiness. Weaknesses at the local, federal and state levels were discussed. Results from local needs and preparedness surveys were examined, including details and summaries of surveys sent to representatives within all states and territories. Significant gaps still remained in protecting the public from biological and chemical attacks. Cut-backs and a lack of resources were identified as contributing to a lack of local preparedness. In addition, emergency responders were not receiving appropriate training. An independent task force reported that less than 10 per cent of fire departments in the United States had the resources, training and equipment needed to respond to a building collapse. It was noted that less than one-quarter of the United States are able to respond 24 hours a day to reports from hospitals of possible victims of biological or chemical attacks. Bioterrorism preparedness still lacks strategic direction, well-defined priorities and appropriate levels of resources to match needs. In addition, although facilities have been identified as risk management program sites, local responders remain unprepared for threats and many local fire and police departments have not been informed of specific plant hazards or information regarding exact chemical hazards. It was concluded that as the United States approaches its fourth anniversary of the 9/11 attacks, there is is much yet to be done to improve the level of preparedness in cities and towns across the country. 31 refs., 2 tabs.

  6. Local Simulations of Instabilities in Relativistic Jets I: Morphology and Energetics of the Current-Driven Instability

    CERN Document Server

    O'Neill, Sean M; Begelman, Mitchell C

    2012-01-01

    We present the results of a numerical investigation of current-driven instability in magnetized jets. Utilizing the well-tested, relativistic magnetohydrodynamic code Athena, we construct an ensemble of local, co-moving plasma columns in which initial radial force balance is achieved through various combinations of magnetic, pressure, and rotational forces. We then examine the resulting flow morphologies and energetics to determine the degree to which these systems become disrupted, the amount of kinetic energy amplification attained, and the non-linear saturation behaviors. Our most significant finding is that the details of initial force balance have a pronounced effect on the resulting flow morphology. Models in which the initial magnetic field is force-free deform, but do not become disrupted. Systems that achieve initial equilibrium by balancing pressure gradients and/or rotation against magnetic forces, however, tend to shred, mix, and develop turbulence. In all cases, the linear growth of current-drive...

  7. Impact of critical care-trained flight paramedics on casualty survival during helicopter evacuation in the current war in Afghanistan.

    Science.gov (United States)

    Mabry, Robert L; Apodaca, Amy; Penrod, Jason; Orman, Jean A; Gerhardt, Robert T; Dorlac, Warren C

    2012-08-01

    The US Army pioneered medical evacuation (MEDEVAC) by helicopter, yet its system remains essentially unchanged since the Vietnam era. Care is provided by a single combat medic credentialed at the Emergency Medical Technician - Basic level. Treatment protocols, documentation, medical direction, and quality improvement processes are not standardized and vary significantly across US Army helicopter evacuation units. This is in contrast to helicopter emergency medical services that operate within the United States. Current civilian helicopter evacuation platforms are routinely staffed by critical care-trained flight paramedics (CCFP) or comparably trained flight nurses who operate under trained EMS physician medical direction using formalized protocols, standardized patient care documentation, and rigorous quality improvement processes. This study compares mortality of patients with injury from trauma between the US Army's standard helicopter evacuation system staffed with medics at the Emergency Medical Technician - Basic level (standard MEDEVAC) and one staffed with experienced CCFP using adopted civilian helicopter emergency medical services practices. This is a retrospective study of a natural experiment. Using data from the Joint Theater Trauma Registry, 48-hour mortality for severely injured patients (injury severity score ≥ 16) was compared between patients transported by standard MEDEVAC units and CCFP air ambulance units. The 48-hour mortality for the CCFP-treated patients was 8% compared to 15% for the standard MEDEVAC patients. After adjustment for covariates, the CCFP system was associated with a 66% lower estimated risk of 48-hour mortality compared to the standard MEDEVAC system. These findings demonstrate that using an air ambulance system based on modern civilian helicopter EMS practice was associated with a lower estimated risk of 48-hour mortality among severely injured patients in a combat setting.

  8. Kinetics deformation of current-voltage characteristics of the varistor oxide structures due to overcharging of the localized states

    Directory of Open Access Journals (Sweden)

    Tonkoshkur A. S.

    2014-12-01

    Full Text Available Prolonged exposure of zinc oxide varistors to the electrical load leads to current-voltage characteristics (CVC deformation, which is associated with a change in the height and width of the intergranular barriers, which are main structural element of the varistors. Polarization phenomena in zinc oxide ceramics are studied in a number of works, but those are mainly limited to the study of the physics of the CVC deformation process and to determining the parameters of localized electronic states involved in this process. This paper presents the results on the simulation of the deformation of pulse CVC of a separate intergranular potential barrier at transient polarization/depolarization, associated with recharging of surface electronic states (SES, which cause this barrier. It is found that at high density of SES their degree of electron filling is small and the effect of DC voltage leads to a shift of pulse current-voltage characteristics into the region of small currents. Conversely, the low density SES are almost completely filled with electrons, and after crystallite polarization CVC is shifted to high currents. Experimental studies have confirmed the possibility of applying the discovered laws to ceramic varistor structures. The proposed model allows interpreting the «anomalous» effects (such as increase in the classification voltage and reduction of active losses power observed during the varistors accelerated aging test.

  9. Alarm setting for the critically ill patient: a descriptive pilot survey of nurses' perceptions of current practice in an Australian Regional Critical Care Unit.

    Science.gov (United States)

    Christensen, Martin; Dodds, Andrew; Sauer, Josh; Watts, Nigel

    2014-08-01

    The aim of this survey was to assess registered nurse's perceptions of alarm setting and management in an Australian Regional Critical Care Unit. The setting and management of alarms within the critical care environment is one of the key responsibilities of the nurse in this area. However, with up to 99% of alarms potentially being false-positives it is easy for the nurse to become desensitised or fatigued by incessant alarms; in some cases up to 400 per patient per day. Inadvertently ignoring, silencing or disabling alarms can have deleterious implications for the patient and nurse. A total population sample of 48 nursing staff from a 13 bedded ICU/HDU/CCU within regional Australia were asked to participate. A 10 item open-ended and multiple choice questionnaire was distributed to determine their perceptions and attitudes of alarm setting and management within this clinical area. Two key themes were identified from the open-ended questions: attitudes towards inappropriate alarm settings and annoyance at delayed responses to alarms. A significant number of respondents (93%) agreed that alarm fatigue can result in alarm desensitisation and the disabling of alarms, whilst 81% suggested the key factors are those associated with false-positive alarms and inappropriately set alarms. This study contributes to what is known about alarm fatigue, setting and management within a critical care environment. In addition it gives an insight as to what nurses' within a regional context consider the key factors which contribute to alarm fatigue. Clearly nursing burnout and potential patient harm are important considerations for practice especially when confronted with alarm fatigue and desensitisation. Therefore, promoting and maintaining an environment of ongoing intra-professional communication and alarm surveillance are crucial in alleviating these potential problems. Copyright © 2014. Published by Elsevier Ltd.

  10. The Effect of Inclination Angle on Critical Heat Flux in a Locally Heated Liquid Film Moving Under the Action of Gas Flow in a Mini-Channel

    Directory of Open Access Journals (Sweden)

    Tkachenko Egor M.

    2016-01-01

    Full Text Available Intensively evaporating liquid films moving under the action of the cocurrent gas flow in a microchannel are promising for the use in modern cooling systems of semiconductor devices with high local heat release. This work has studied the dependence of the critical heat flux on the inclination angle of the channel. It has been found that the inclination angle in the plane parallel to the flow has no significant effect on the critical heat flux. Whereas the inclination angle in the plane perpendicular to the flow, on the contrary, significantly changes the value of the critical heat flux. However, for a given flow rate of fluid there is a threshold gas velocity at which the critical heat flux does not differ from the case of zero inclination of the channel. Thus, it can be concluded that the cooling system based on shear-driven liquid films can be potentially used when direction of the gravity changes.

  11. Improved critical current densities in bulk FeSe superconductor using ball milled powders and high temperature sintering

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, M.; Furutani, K.; Murakami, M. [Graduate School of Science and Engineering, Superconducting Materials Laboratory, Shibaura Institute of Technology, Tokyo (Japan); Kumar, Dinesh; Rao, M.S. Ramachandra [Department of Physics, Nano Functional Materials Technology Centre and Materials Science Research Centre, Indian Institute of Technology Madras, Chennai (India); Koblischka, M.R. [Institute of Experimental Physics, Saarland University, Saarbruecken (Germany)

    2016-12-15

    The present study is investigating the effect of high temperature sintering combined with ball milled powders for the preparation of FeSe material via solid state sintering technique. The commercial powders of Fe (99.9% purity) and Se (99.9% purity) were mixed in a nominal ratio Fe:Se = 1:1 and thoroughly ground and ball-milled in a glove box during 6 h. Then, the powder mixture was pressed into pellets of 5 mm in diameter and 2 mm thickness using an uniaxial pressure of 100 MPa. The samples were sealed in quartz tubes and sintered at 600 C for 24 h. Then, the pellets were again thoroughly ground and ball-milled in the glove box and pressed into pellets, and the final sintering was performed at two different temperatures, namely at 900 C for 24 h and at 950 C for 24 h. X-ray diffraction results confirmed that both samples showed mainly of the β-FeSe with tetragonal structure. The temperature dependence of magnetization (M-T) curves revealed a sharp superconducting transition T{sub c,} {sub onset} = 8.16 K for the sample sintered at 900 C. Further, scanning electron microscopy observations proved that samples sintered at 900 C show a platelike grain structure with high density. As a result, improved irreversibility fields around 5 T and the critical current density (J{sub c}) values of 6252 A cm{sup -2} at 5 K and self-field are obtained. Furthermore, the normalized volume pinning force versus the reduced field plots indicated a peak position at 0.4 for the sample sintered at 900 C. Improved flux pinning and the high J{sub c} values are attributed to the textured microstructure of the material, produced by a combination of high temperature sintering and ball milling. (copyright 2016 The Authors. Phys. Status Solidi A published by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Implementing a Grant Proposal Writing Exercise in Undergraduate Science Courses to Incorporate Real-World Applications and Critical Analysis of Current Literature

    Science.gov (United States)

    Cole, Kathryn E.; Inada, Maki; Smith, Andrew M.; Haaf, Michael P.

    2013-01-01

    Writing is an essential part of a successful career in science. As such, many undergraduate science courses have begun to implement writing assignments that reflect "real-world" applications and focus on a critical analysis of current literature; these assignments are often in the form of a review or a research proposal. The…

  13. Correlations between critical current density, j{sub c}, critical temperature, T{sub c}, and structural quality of Y{sub 1}B{sub 2}Cu{sub 3}O{sub 7-x} thin superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Chrzanowski, J.; Xing, W.B.; Atlan, D. [Simon Fraser Univ., British Columbia (Canada)] [and others

    1994-12-31

    Correlations between critical current density (j{sub c}) critical temperature (T{sub c}) and the density of edge dislocations and nonuniform strain have been observed in YBCO thin films deposited by pulsed laser ablation on (001) LaAlO{sub 3} single crystals. Distinct maxima in j{sub c} as a function of the linewidths of the (00{ell}) Bragg reflections and as a function of the mosaic spread have been found in the epitaxial films. These maxima in j{sub c} indicate that the magnetic flux lines, in films of structural quality approaching that of single crystals, are insufficiently pinned which results in a decreased critical current density. T{sub c} increased monotonically with improving crystalline quality and approached a value characteristic of a pure single crystal. A strong correlation between j{sub c} and the density of edge dislocations N{sub D} was found. At the maximum of the critical current density the density of edge dislocations was estimated to be N{sub D}{approximately}1-2 x 10{sup 9}/cm{sup 2}.

  14. Lateral critical current distribution and self-field profile of Bi-2223/Ag conductors: measurements and calculations

    NARCIS (Netherlands)

    Demencik, E.; Usak, P.; Polak, M.; Piel, H.; Dhalle, M.

    2006-01-01

    The lateral current distribution and the magnetic self-field induced by a transport current were measured independently in three multifilament Bi-2223/Ag tapes with qualitatively different filament layouts. The current and field data from these two experiments, magnetic knife and scanning Hall probe

  15. Lateral critical current distribution and self-field profile of Bi-2223/Ag conductors: measurements and calculations

    NARCIS (Netherlands)

    Demencik, E.; Usak, P.; Polak, M.; Piel, H.; Dhalle, Marc M.J.

    2006-01-01

    The lateral current distribution and the magnetic self-field induced by a transport current were measured independently in three multifilament Bi-2223/Ag tapes with qualitatively different filament layouts. The current and field data from these two experiments, magnetic knife and scanning Hall

  16. The critical period of high mortality of larvae fish —A discussion based on current research

    Science.gov (United States)

    Li, Sifa; Mathias, J. A.

    1987-03-01

    Most fishes suffer high mortality during early development stages. The existence of a “critical period” was hypothesized by Hjort (1914). However, several decades of research have resulted in considerable controversy over the hypothesis. This paper attempts to clarify the critical period concept, demonstrate its usefulness, and resolve some of the controversy surrounding it. Based on our own studies and the literature, we find that within the “aquaculture school” (those concerned with culturing fishes, particulary larval stages), there is a great deal of evidence for the critical period concept. But we redefine the concept of “critical period” of mortality of fish larvae in this way. The deepest, sharpest, and fastest physiological and ecological changes during the development of the larvae are produced with the shift from endogenous nutrition to exogenous. At this stage, the old functions are quickly being replaced by new functions inside the body. Because of this shifting of function and imperfection of organs, the larvae are most sensitive at this time to environmental factors, particularly food supply. A higher specific mortality rate often occurs immediately folowing the period of strictly endogenous yolk feeding, and during the period of first exogenous feeding. Then it may be followed by a lower specific mortality rate. The significance of a “critical period” for fish populations is discussed. A good understanding of the “critical period” would provide a means for predicting the strength of year classes in natural fish populations, and also suggests approaches for increasing survival in aquaculture systems.

  17. Optimization of sintering conditions in bulk MgB{sub 2} material for improvement of critical current density

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, M., E-mail: miryala1@shibaura-it.ac.jp [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Nozaki, K.; Kobayashi, H. [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Zeng, X.L.; Koblischka-Veneva, A.; Koblischka, M.R. [Experimental Physics, Saarland University, P.O. Box 151150, 66041 Saarbrücken (Germany); Inoue, K.; Murakami, M. [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan)

    2015-11-15

    The present investigation focuses on methods to further improve the J{sub c} values of disk-shaped bulk MgB{sub 2} superconductors by optimizing the sintering conditions. We prepared two sets of bulk MgB{sub 2} material from commercial high-purity powders of Mg metal and amorphous B using a single-step solid-state reaction process. To optimize the sintering time, a set of samples was sintered at 775 °C with sintering duration ranging between 1 and 10 h (pure Ar atmosphere). A second set of samples was produced similarly at 775, 780, 785, 795, 800 and 805 °C (3 h, pure argon atmosphere). X-ray diffraction analysis showed that both sets of samples were single phase MgB{sub 2}. Magnetization measurements confirmed a sharp superconducting transition with T{sub c,onset} ≈ 38.2 K–38.8 K. The critical current density (J{sub c}) values for MgB{sub 2} samples produced for 1 h were the highest in all processed materials, i.e., the high J{sub c} value of 270,000 A/cm{sup 2} and 125,000 A/cm{sup 2} (20 K, self-field and 1 T) were achieved in the sample produced at 775 °C, without any additional doping. In contrast, the second series of samples clearly indicated that at 805 °C (3 h) the highest J{sub c} of 245,000 A/cm{sup 2} and 110,000 A/cm{sup 2} (20 K, self-field and 1 T) were achieved. AFM and EBSD observations indicated that largest amount of fine grains do exist in the sample sintered at 775 °C, but the narrowest distribution of grains does exist in the sample sintered at 800 °C. The present results clearly demonstrate a strong relation between the microstructure and the pinning performance. The optimization of the sintering conditions is crucial to improve the performance of bulk MgB{sub 2} samples. - Highlights: • We had successfully improved the performance of sintered, pure bulk MgB{sub 2} materials. • EBSD observations clarified that the grain sizes are in the 100–500 nm range. • The high J{sub c} value at 20 K, 0 T and 1 T are 2.70 × 10{sup 5} A

  18. Mechanisms of Silver Nanoparticle Release, Transformation and Toxicity: A Critical Review of Current Knowledge and Recommendations for Future Studies and Applications

    Directory of Open Access Journals (Sweden)

    Iseult Lynch

    2013-06-01

    Full Text Available Nanosilver, due to its small particle size and enormous specific surface area, facilitates more rapid dissolution of ions than the equivalent bulk material; potentially leading to increased toxicity of nanosilver. This, coupled with their capacity to adsorb biomolecules and interact with biological receptors can mean that nanoparticles can reach sub-cellular locations leading to potentially higher localized concentrations of ions once those particles start to dissolve or degrade in situ. Further complicating the story is the capacity for nanoparticles to generate reactive oxygen species, and to interact with, and potentially disturb the functioning of biomolecules such as proteins, enzymes and DNA. The fact that the nanoparticle size, shape, surface coating and a host of other factors contribute to these interactions, and that the particles themselves are evolving or ageing leads to further complications in terms of elucidating mechanisms of interaction and modes of action for silver nanoparticles, in contrast to dissolved silver species. This review aims to provide a critical assessment of the current understanding of silver nanoparticle toxicity, as well as to provide a set of pointers and guidelines for experimental design of future studies to assess the environmental and biological impacts of silver nanoparticles. In particular; in future we require a detailed description of the nanoparticles; their synthesis route and stabilisation mechanisms; their coating; and evolution and ageing under the exposure conditions of the assay. This would allow for comparison of data from different particles; different environmental or biological systems; and structure-activity or structure-property relationships to emerge as the basis for predictive toxicology. On the basis of currently available data; such comparisons or predictions are difficult; as the characterisation and time-resolved data is not available; and a full understanding of silver

  19. Superconducting tapes with critical current density of 10 sup 4 A/cm sup 2 at 77 K and zero magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Narumi, E.; Song, L.W.; Hwa, S.; Ye, J.; Yang, F.; Kao, Y.H.; Patel, S.; Shaw, D.T. (New York State Inst. on Superconductivity, State Univ. of New York at Buffalo, Buffalo, NY (US)); Tkaczyk, J.E. (General Electric Co., Schenectady, NY (United States). Corporate Research and Development Center)

    1991-03-01

    This paper reports on critical current density above 10{sup 4} A/cm{sup 2} at both YBa{sub 2}Cu{sub 3}O{sub 6.8} (YBCO) thin films on metallic substrates and Bi-based superconducting films on silver tapes. A transition buffer, consisting of sub-buffers deposited at different temperatures, was used to enhance the crystallinity and the transport properties of YBCO films on metallic substrates. YBCO films were fabricated, using in-situ laser deposition, and they were strongly c-axis oriented. Critical temperature of 87 K and critical current density of 3 {times} 10{sup 4} A/cm{sup 2} at 77 K were obtained for a 0.5 {mu}m-thick YBCO film. Also, the magnetic field dependence of J{sub c} could be increased by using Pt-coated metallic substrates. For 10 {approximately} 20 {mu}m-thick Bi-based superconducting tape, by using brush-on technique and heat treatment, critical current of 10{sup 4} A/cm{sup 2} at 77 K was obtained.

  20. Using Critical Incidents of Instructional Design and Multimedia Production Activities to Investigate Instructional Designers' Current Practices and Roles

    Science.gov (United States)

    Sugar, William A.; Luterbach, Kenneth J.

    2016-01-01

    Through consideration of critical incidents, this study analyzed 106 effective, ineffective and extraordinary instructional design and multimedia production (MP) activities discussed by 36 instructional design professionals. This evaluation provided insights into these professionals' best and not so best practices during the past 6 months.…

  1. Investigation of local heterogeneity of hbO2 and hb in working dog heart in situ under isovolemic hemodilution and critical coronary stenosis

    Science.gov (United States)

    Krug, Alfons; Kessler, Manfred D.; Khuri, Raja; Lust, Robert; Chitwood, Randolph

    1996-12-01

    A tissue spectrophotometer (EMPHO II) working with 70 micrometer micro lightguide sensors enables recording of spectra in the visible wavelength range (500 - 630 nm). During an initial period arterial hypoxia and hyperoxia were induced on working dog heart by mechanical ventilation with oxygen fractions (fiO2) of 0.1 and 0.5. Under these conditions the effects of low and high fiO2 on oxygenation distribution of intracapillary hemoglobin were investigated. In the second part of the experiment the relation between systemic hematocrit, local hemoglobin concentration, local hemoglobin oxygenation and the oxygen regulation mechanism were studied in detail. In the final part of the experiment the effect of critical coronary stenosis on hb and hbO2 was measured. Critical stenosis was achieved by partial clamping of the left anterior coronary artery (LAD).

  2. Influence of operation factors on brittle fracture initiation and critical local normal stress in SE(B) type specimens of VVER reactor pressure vessel steels

    Science.gov (United States)

    Kuleshova, E. A.; Erak, A. D.; Kiselev, A. S.; Bubyakin, S. A.; Bandura, A. P.

    2015-12-01

    A complex of mechanical tests and fractographic studies of VVER-1000 RPV SE(B) type surveillance specimens was carried out: the brittle fracture origins were revealed (non-metallic inclusions and structural boundaries) and the correlation between fracture toughness parameters (CTOD) and fracture surface parameters (CID) was established. A computational and experimental method of the critical local normal stress determination for different origin types was developed. The values of the critical local normal stress for the structural boundary origin type both for base and weld metal after thermal exposure and neutron irradiation are lower than that for initial state due to the lower cohesive strength of grain boundaries as a result of phosphorus segregation.

  3. Critical current densities and n-values of MgB2 strands over a wide range of temperatures and fields

    Science.gov (United States)

    Li, G. Z.; Yang, Y.; Susner, M. A.; Sumption, M. D.; Collings, E. W.

    2012-02-01

    Transport measurements of critical current density, Jct, in monocore powder-in-tube MgB2 strands have been carried out at temperatures, T, of from 4.2 to 40 K, and in transverse fields, B, of up to 14 T. Processing methods used were conventional continuous tube forming/filling (CTFF) and internal magnesium diffusion (IMD). Strands with several powder compositions were measured, including binary (undoped) MgB2, 2% carbon doped MgB2, and 3% carbon doped MgB2. Magnetization loops (M-B) were also measured, and magnetic critical current density, Jcm, values extracted from them. The transport, Jct(B) and magnetic, Jcm(B), critical current densities were compared. Also studied was the influence of doping on the resistively measured irreversibility field, Birr, and upper critical field, Bc2. Critical current densities, Jct, and n-values were extracted from transport measurements and were found to be universally related (for all B and T) according to n\\propto {J}_{{ct}}^{m} in which m = 0.52 ± 0.11. Likewise n was found to be related to B according to n ∝ B-p with a T-dependent p in the range of about 0.08-0.21. Further analysis of the field (B) and temperature (T) dependences of n-value resulted in an expression that enabled n(B,T), for all B and T, to be estimated for a given strand based on the results of transport Jct(B) measurements made at one arbitrarily chosen temperature.

  4. A critical analysis of the combined usage of protein localization prediction methods: Increasing the number of independent data sets can reduce the accuracy of predicted mitochondrial localization

    Science.gov (United States)

    Lythgow, Kieren T.; Hudson, Gavin; Andras, Peter; Chinnery, Patrick F.

    2011-01-01

    In the absence of a comprehensive experimentally derived mitochondrial proteome, several bioinformatic approaches have been developed to aid the identification of novel mitochondrial disease genes within mapped nuclear genetic loci. Often, many classifiers are combined to increase the sensitivity and specificity of the predictions. Here we show that the greatest sensitivity and specificity are obtained by using a combination of seven carefully selected classifiers. We also show that increasing the number of independent prediction methods can paradoxically decrease the accuracy of predicting mitochondrial localization. This approach will help to accelerate the identification of new mitochondrial disease genes by providing a principled way for the selection for combination of appropriate prediction methods of mitochondrial localization of proteins. PMID:21195798

  5. Local interaction scale controls the existence of a non-trivial optimal critical mass in opinion spreading

    CERN Document Server

    Wu, Zhi-Xi

    2010-01-01

    We study a model of opinion formation where the collective decision of group is said to happen if the fraction of agents having the most common opinion exceeds a threshold value, a \\textit{critical mass}. We find that there exists a unique, non-trivial critical mass giving the most efficient convergence to consensus. In addition, we observe that for small critical masses, the characteristic time scale for the relaxation to consensus splits into two. The shorter time scale corresponds to a direct relaxation and the longer can be explained by the existence of intermediate, metastable states similar to those found in [P.\\ Chen and S.\\ Redner, Phys.\\ Rev.\\ E \\textbf{71}, 036101 (2005)]. This longer time-scale is dependent on the precise condition for consensus---with a modification of the condition it can go away.

  6. Intelligent Cycled Current Ice Melting Method and Its Critical Ice-Melting Current Study%智能循环电流融冰方法及其临界融冰电流研究

    Institute of Scientific and Technical Information of China (English)

    舒立春; 罗保松; 蒋兴良; 胡琴; 李特; 兰强

    2012-01-01

    In this paper,intelligent cycled current ice melting method which groups the bundle conductor sub-conductors and allows the total transmission line load current to flow through each sub-conductor group to achieve the ice melting of the transmission line is proposed.Then based on the analysis of heat balance of the ice and conductor surface under critical ice melting condition in the glaze icing process,a method to calculate the critical current of intelligent cycled current ice melting method is established.The model is tested by experiment in artificial climate chamber.Finite element simulation model is also created.The results of them are basically consistent with each other.Then the factors affecting the critical ice-melting current are analyzed,and the critical ice-melting current under weather conditions of serious icing disaster in recent years is calculated and compared with the current corresponding to economic current density.The results show that: under the same conditions,the critical icing melting current for intelligent cycled current ice melting method is lower than the critical ice-melting current for DC Short-circuit method.Critical icing melting current is related to ambient temperature,wind speed and ice thickness.Under the same environmental parameters,the effect of ice thickness on critical icing melting current is not obvious,under the same ice thickness,critical icing melting current shows gradually saturated increasing trends with lowering ambient temperature or increasing wind speed.The current corresponding to economic current density is higher than the critical ice-melting current under weather conditions of serious icing disaster and retains sufficient margin.Therefore,intelligent cycled current in the view of choosing ice-melting current is feasible.%提出了对分裂导线子导线进行分组并将输电线路总负荷电流循环通流至各子导线组以实现输电线路融冰的智能循环电流融冰方法。通过对雨凇覆

  7. Youth Arts, Media, and Critical Literacies as Forms of Public Engagement in the Local/Global Interface

    Science.gov (United States)

    Rogers, Theresa

    2016-01-01

    This article provides a reanalysis of a multisited case study of youth arts, media, and critical literacy to theorize the role of networked and physical "publics" within which youth engage with issues they care about, making claims about their lived experiences. An understanding of the nature and role of publics is crucial to productive…

  8. Ecopedagogy as an Element of Citizenship Education: The Dialectic of Global/Local Spheres of Citizenship and Critical Environmental Pedagogies

    Science.gov (United States)

    Misiaszek, Greg William

    2016-01-01

    Emerging from popular education movements in Latin America, "ecopedagogy" is a critical environmental pedagogy which focuses on understanding the connections between social conflict and environmentally harmful acts carried out by humans. These connections are often politically hidden in education. Ecopedagogy, while being pluralistic, is…

  9. Enhancement of the critical current density in FeO-coated MgB2 thin films at high magnetic fields

    Directory of Open Access Journals (Sweden)

    Andrei E. Surdu

    2011-12-01

    Full Text Available The effect of depositing FeO nanoparticles with a diameter of 10 nm onto the surface of MgB2 thin films on the critical current density was studied in comparison with the case of uncoated MgB2 thin films. We calculated the superconducting critical current densities (Jc from the magnetization hysteresis (M–H curves for both sets of samples and found that the Jc value of FeO-coated films is higher at all fields and temperatures than the Jc value for uncoated films, and that it decreases to ~105 A/cm2 at B = 1 T and T = 20 K and remains approximately constant at higher fields up to 7 T.

  10. Iodine-131 metaiodobenzylguanidine (I-131 MIBG) diagnosis and therapy of pheochromocytoma and paraganglioma: current problems, critical issues and presentation of a sample case.

    Science.gov (United States)

    Castellani, M R; Aktolun, C; Buzzoni, R; Seregni, E; Chiesa, C; Maccauro, M; Aliberti, G L; Vellani, C; Lorenzoni, A; Bombardieri, E

    2013-06-01

    Iodine-131 metaiodobenzylguanidine (I-131 MIBG) has been used for the diagnosis and treatment of malignant pheochromocytomas (PHEO) and paragangliomas (PGL) since 1980's. Despite increasing amount of experience with iodine-131 (I-131) MIBG therapy, many important questions still exist. In this article, we will discuss the current problems learned from clinical experience in diagnosis and therapy of PHEO/PGL with I-131 MIBG, and present a sample case to emphasize the critical aspects for an optimal treatment strategy.

  11. A Critical Evaluation of the Influence of the Dark Exchange Current on the Performance of Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Rodrigo García-Rodríguez

    2016-01-01

    Full Text Available The influence of the thickness of the nanostructured, mesoporous TiO2 film on several parameters determining the performance of a dye-sensitized solar cell is investigated both experimentally and theoretically. We pay special attention to the effect of the exchange current density in the dark, and we compare the values obtained by steady state measurements with values extracted from small perturbation techniques. We also evaluate the influence of exchange current density, the solar cell ideality factor, and the effective absorption coefficient of the cell on the optimal film thickness. The results show that the exchange current density in the dark is proportional to the TiO2 film thickness, however, the effective absorption coefficient is the parameter that ultimately defines the ideal thickness. We illustrate the importance of the exchange current density in the dark on the determination of the current–voltage characteristics and we show how an important improvement of the cell performance can be achieved by decreasing values of the total series resistance and the exchange current density in the dark.

  12. Extracorporeal membrane oxygenation (ECMO) for critically ill adults in the emergency department: history, current applications, and future directions.

    Science.gov (United States)

    Mosier, Jarrod M; Kelsey, Melissa; Raz, Yuval; Gunnerson, Kyle J; Meyer, Robyn; Hypes, Cameron D; Malo, Josh; Whitmore, Sage P; Spaite, Daniel W

    2015-12-17

    Extracorporeal membrane oxygenation (ECMO) is a mode of extracorporeal life support that augments oxygenation, ventilation and/or cardiac output via cannulae connected to a circuit that pumps blood through an oxygenator and back into the patient. ECMO has been used for decades to support cardiopulmonary disease refractory to conventional therapy. While not robust, there are promising data for the use of ECMO in acute hypoxemic respiratory failure, cardiac arrest, and cardiogenic shock and the potential indications for ECMO continue to increase. This review discusses the existing literature on the potential use of ECMO in critically ill patients within the emergency department.

  13. Heavy metal in the intensive care unit: a review of current literature on trace element supplementation in critically ill patients.

    Science.gov (United States)

    Rech, Megan; To, Long; Tovbin, Alina; Smoot, Thomas; Mlynarek, Mark

    2014-02-01

    Trace elements are essential for many physiologic processes. In recent years, supplementation has been studied for a variety of indications, including glycemic control, wound healing, antioxidant effect, and anemia. Critical illness, especially states such as burns, traumas, and septic shock, is associated with inflammatory and oxidative stress, immune dysfunction, and malnutrition. In these patients, enteral and parenteral nutrition or pharmaceutical supplementation is used to provide essential macronutrients, including trace elements. The purpose of this review is to describe trace element supplementation, including iron, copper, chromium, manganese, selenium, and zinc, and highlight their mechanism, pharmacology, outcome data, and adverse effects.

  14. Influence of Critical Current Density on Guidance Force Decay of HTS Bulk Exposed to AC Magnetic Field Perturbation in a Maglev Vehicle System

    Science.gov (United States)

    Longcai, Zhang; Jianguo, Kong

    2012-07-01

    Superconducting maglev vehicle is one of the most promising applications of HTS bulks. In such a system, the HTS bulks are always exposed to AC external magnetic field, which is generated by the inhomogeneous surface magnetic field of the NdFeB guideway. In our previous work, we studied the guidance force decay of the YBCO bulk over the NdFdB guideway used in the High-temperature superconducting maglev vehicle system with the application of the AC external magnetic field, and calculated the guidance force decay as a function of time based on an analytic model. In this paper, we investigated the influence of the critical current density on the guidance force decay of HTS bulk exposed to AC field perturbation in the maglev vehicle system and try to adopt a method to suppress the decay. From the results, it was found that the guidance force decay rate was higher for the bulk with lower critical current density. Therefore, we could suppress the guidance force decay of HTS bulk exposed to AC external magnetic field perturbation in the maglev vehicle system by improving critical current density of the bulk.

  15. Meeting the Challenge of Health Literacy in Rural Uganda: The Critical Role of Women and Local Modes of Communication

    Science.gov (United States)

    Kendrick, Maureen; Mutonyi, Harriet

    2007-01-01

    This article seeks to better understand the relation between local and traditional modes of communication and health literacy within the context of a rural West Nile community in Northern Uganda. Drawing on social semiotics (multimodality) and Bakhtin's notion of the carnival, the focus is on a group of women participating in a grassroots literacy…

  16. Early depth assessment of local burns by videomicroscopy: 24 h after injury is a critical time point.

    Science.gov (United States)

    Mihara, Kyomi; Shindo, Hajime; Ohtani, Minako; Nagasaki, Kotaro; Nakashima, Reiko; Katoh, Norito; Kishimoto, Saburo

    2011-09-01

    Videomicroscopy has simple and prompt operability, and useful in the burn depth assessment in its early phase. A burn wound is, however, a dynamic environment in the first few days and the critical time to assess a burn wound by videomicroscopy has not been investigated. The aim of this study is to investigate the critical time point to assess the burn depth by videomicroscopy. Forty one patients with 44 intermediate depth burns admitted within 7 days after injury were included. Accuracies were assessed by comparison with clinical outcome: healing within 21 days after injury or not with conservative treatment. We prospectively evaluated and compared the accuracy of the videomicroscopy measurements with the clinical assessments. All findings were serialized in order of time after injury and divided into three groups, and we compared the appreciation of burn depth by videomicroscopy findings among groups. The videomicroscopy measurements is significantly accurate compared with clinical assessments (p=0.001). The accuracy of videomicroscopy measurements was significantly lower in the post-injury burn depth and the critical time point to assess the burn depth by videomicroscopy is 24 h after injury. Copyright © 2011 Elsevier Ltd and ISBI. All rights reserved.

  17. Statistical Analysis and Modeling of the Local Ionospheric Critical Frequency: A Mid-latitude Single-Station Model for Use in Forecasting

    Science.gov (United States)

    Sapundjiev, Danislav; Stankov, Stanimir M.

    2016-06-01

    The hourly values of the F-layer critical frequency from the ionospheric sounder in Dourbes (50.1°N, 4.6°E) during the time interval from 1957 to 2010, comprising five solar cycles, were analyzed for the effects of the solar activity. The hourly time series were reduced to hourly monthly medians which in turn were used for fitting a single station foF 2 monthly median model. Two functional approaches have been investigated: a statistical approach and a spectral approach. The solar flux F 10.7 is used to model the dependence of foF 2 on the solar activity and is incorporated into both models by a polynomial expression. The statistical model employs polynomial functions to fit the F-layer critical frequency while the spectral model is based on spectral decomposition of the measured data and offers a better physical interpretation of the fitting parameters. The daytime and nighttime foF 2 values calculated by both approaches are compared during high and low solar activity. In general, the statistical model has a slightly lower uncertainty at the expense of the larger number of fitting parameters. However, the spectral approach is superior for modeling the periodic effects and performs better when comparing the results for high and low solar activity. Comparison with the International Reference Ionosphere (IRI 2012) shows that both local models are better at describing the local values of the F-layer critical frequency.

  18. Indications of a Quantum Critical Point in Bi2Sr2CaCu2O8+δ Using a Local Kondo Effect

    Science.gov (United States)

    Calleja, Eduardo; Dai, Jixia; Arnold, Gerald; Gu, Genda; McElroy, Kyle

    2014-03-01

    A complete understanding of the complex phase diagrams that are present in high temperature superconductors remains elusive. While there is an overwhelming amount of experimental data on the existence and interplay of the phases present in high Tc superconductors from local probes, much of the existing data only looks at the charge degree of freedom of the material. By substituting Fe atoms for Cu atoms in the CuO plane of Bi2Sr2CaCu2O8+δ (Bi2212), we gain the ability to access the spin degree of freedom since the Fe atoms retain their magnetization below the superconducting transition temperature. This leads to a local Kondo effect which can be observed using Spectroscopic-Imaging Scanning Tunneling Microscopy (SI-STM) and the local Kondo temperature can be extracted from spectra via a theoretical model. We show that the examination of this local Kondo temperature across local and sample average doping leads to the observation of a change in the quasiparticle spin degree of freedom at a quantum critical point (QCP) with a nominal hole doping of roughly 0.22, in agreement with other probes. The observation of the QCP in Bi2212 with this new method to access the spin degree of freedom helps to unravel some of the mystery behind the complex phase diagram of Bi2212.

  19. buffer Layer Growth, the Thickness Dependence of Jc in Coated Conductors, Local Identification of Current Limiting Mechanisms and Participation in the Wire Development Group

    Energy Technology Data Exchange (ETDEWEB)

    Larbalestier, David; Hellstron, Eric; Abraimov, Dmytro

    2011-12-17

    The primary thrusts of our work were to provide critical understanding of how best to enhance the current-carrying capacity of coated conductors. These include the deconstruction of Jc as a function of fim thickness, the growth of in situ films incorporating strong pinning centers and the use of a suite of position-sensitive tools that enable location and analysis of key areas where current-limiting occurs.

  20. Many-body localization and new critical phenomena in regular random graphs and constrained Erd\\H{o}s-Renyi networks

    CERN Document Server

    Avetisov, V; Nechaev, S; Valba, O

    2016-01-01

    We consider from the localization perspective the new critical behavior discovered recently for the regular random graphs (RRG) and constrained Erd\\H{o}s-Renyi networks (CERN). The diagonal disorder for standard models, we replace by the fugacity $\\mu$ of triads in the RRG and CERN. At some critical value of $\\mu$ the network decays into the maximally possible number of almost full graphs, and the adjacency matrix acquires the two-gapped structure. We find that the eigenvalue statistics corresponds to delocalized states in the central zone, and to the localized states in the side one. The mobility edge lies between zones. We apply these findings to the many-body localization assuming the approximation of the hierarchical structure of the Fock space (for some interacting many-body system) by the RGG and by CERN with some vertex degree. We allow the 3-cycles in the Fock space and identify particles in the many-body system above the phase transition with clusters in the RRG. We discuss the controversial issue of...

  1. A Critical Analysis of Rejection in Vascularized Composite Allotransplantation: Clinical, cellular and molecular aspects, Current Challenges, and Novel Concepts

    Directory of Open Access Journals (Sweden)

    Karim A Sarhane

    2013-11-01

    Full Text Available Advances in microsurgical techniques and immunomodulatory protocols have contributed to the expansion of Vascularized Composite Allotransplantation (VCA with very encouraging immunological, functional, and cosmetic results. Rejection remains however a major hurdle that portends serious threats to recipients. Rejection features in VCA have been described in a number of studies, and an international consensus on the classification of rejection was established. Unfortunately, current available diagnostic methods carry many shortcomings that, in certain cases, pose a great diagnostic challenge to physicians especially in borderline rejection cases. In this review, we revisit the features of acute skin rejection in hand and face transplantation at the clinical, cellular and molecular levels. The multiple challenges in diagnosing rejection and in defining chronic and antibody-mediated rejection in VCA are then presented, and we finish by analyzing current research directions and novel concepts aiming at improving available diagnostic measures.

  2. Current and calcium responses to local activation of axonal NMDA receptors in developing cerebellar molecular layer interneurons.

    Directory of Open Access Journals (Sweden)

    Bénédicte Rossi

    Full Text Available In developing cerebellar molecular layer interneurons (MLIs, NMDA increases spontaneous GABA release. This effect had been attributed to either direct activation of presynaptic NMDA receptors (preNMDARs or an indirect pathway involving activation of somato-dendritic NMDARs followed by passive spread of somatic depolarization along the axon and activation of axonal voltage dependent Ca(2+ channels (VDCCs. Using Ca(2+ imaging and electrophysiology, we searched for preNMDARs by uncaging NMDAR agonists either broadly throughout the whole field or locally at specific axonal locations. Releasing either NMDA or glutamate in the presence of NBQX using short laser pulses elicited current transients that were highly sensitive to the location of the spot and restricted to a small number of varicosities. The signal was abolished in the presence of high Mg(2+ or by the addition of APV. Similar paradigms yielded restricted Ca(2+ transients in interneurons loaded with a Ca(2+ indicator. We found that the synaptic effects of NMDA were not inhibited by blocking VDCCs but were impaired in the presence of the ryanodine receptor antagonist dantrolene. Furthermore, in voltage clamped cells, bath applied NMDA triggers Ca(2+ elevations and induces neurotransmitter release in the axonal compartment. Our results suggest the existence of preNMDARs in developing MLIs and propose their involvement in the NMDA-evoked increase in GABA release by triggering a Ca(2+-induced Ca(2+ release process mediated by presynaptic Ca(2+ stores. Such a mechanism is likely to exert a crucial role in various forms of Ca(2+-mediated synaptic plasticity.

  3. The effects of distractor sounds presented through bone conduction headphones on the localization of critical environmental sounds.

    Science.gov (United States)

    May, Keenan R; Walker, Bruce N

    2017-05-01

    Bone conduction headphones are devices that transmit sound through the bones of a listener's head rather than through the air in their outer ear. They have been marketed as a safer way to enjoy audio content while walking, jogging, or cycling. However, listening to distracting sounds over bone conduction may still disrupt a listener's awareness of their auditory environment. The present study investigated the nature of this interference with the faculty of sound source localization-a key prerequisite for generating situation awareness through audio. Participants sat in the middle of a circle of loudspeakers and listened for target sounds played from different directions. Each time they heard a sound, they responded by indicating what direction they judged the sound to have come from. Meanwhile, participants listened to distractor sounds played through bone conduction headphones. Participants heard (1) no distractor sounds, (2) a spoken story that they were instructed to ignore, and (3) the same spoken story that they were instructed to attend to. For conditions (2) and (3), some participants heard a version of the story with background music, while others heard the spoken story without the music. Participants had greater localization error in the distractor-present conditions. Additionally, participants who heard the spoken story with music exhibited greater localization error. However, there was no effect of whether participants ignored or attended to distractors. This pattern was attributed to masking effects, and was more pronounced for narrow-band targets compared to broadband targets. Post-hoc analyses found evidence of a 'pulling' effect, in which localization judgments were systematically biased toward the apparent direction of the bone conducted distractors. These results indicate that using bone conduction headphones can be expected to cause a decline in a person's awareness of their environment, in a subtle way that a jogger or cyclist might not be

  4. Critical Accountability: Preventing and Interdicting Terrorist Activity in the U.S. By Effectively Utilizing State and Local Law Enforcement

    Science.gov (United States)

    2009-03-01

    5 Magna Carta Plus, The Nine Principles by Sir Robert Peel, Magna Carta Plus, (November 20020) http://www.magnacartaplus.org...country as effective as having state and local representation from the actual areas that will be working together?34 This question will be examined...proxy for reducing the supply of drugs in the United States. • The PMP focuses on the common features of what HIDTAs actually try to do (again

  5. Phase Transition and Critical Values of a Nearest-Neighbor System with Uncountable Local State Space on Cayley Trees

    Energy Technology Data Exchange (ETDEWEB)

    Jahnel, Benedikt, E-mail: Benedikt.Jahnel@ruhr-uni-bochum.de; Külske, Christof, E-mail: Christof.Kuelske@ruhr-uni-bochum.de [Ruhr-Universität Bochum, Fakultät für Mathematik (Germany); Botirov, Golibjon I., E-mail: botirovg@yandex.ru [Bukhara State University, Faculty of Physics and Mathematics (Uzbekistan)

    2014-12-15

    We consider a ferromagnetic nearest-neighbor model on a Cayley tree of degree k2 with uncountable local state space [0,1] where the energy function depends on a parameter θ ∊[0, 1). We show that for 0θ(5/(3k)) the model has a unique translation-invariant Gibbs measure. If 5/(3k) <θ < 1, there is a phase transition, in particular there are three translation-invariant Gibbs measures.

  6. Vortex pinning properties in Co-doped BaFe2As2 thin films with a high critical current density over 2 MA cm-2 at 9 T

    Science.gov (United States)

    Yuan, Pusheng; Xu, Zhongtang; Wang, Dongliang; Zhang, Ming; Li, Jianqi; Ma, Yanwei

    2017-02-01

    Similar to other high-temperature superconductors, the pinning centers largely determine the critical current density (J c) in Co-doped BaFe2As2 (Ba122:Co). Therefore, understanding the vortex pinning mechanism of high-J c Ba122:Co thin films is important for the applications of Ba122:Co. Herein we report the pinning of the naturally grown defects in Ba122:Co thin films with a high critical current density. The transport J c of thin films is up to 2.6 MA cm-2 in 9 T at 4.2 K, which is the highest value in iron-based superconductors. Microstructure investigations reveal a high density of ab-planar defects (stacking faults) and localized vertical defects present in the sample. The Dew-Hughes mode analyses prove that pinning centers by surface defects and by point defects are responsible for H//ab and H//c, respectively. Therefore, the high J c in strong magnetic field for both H//ab and H//c are related to surface and point defects which act as the pinning centers in Ba122:Co films.

  7. Critical appraisal of assumptions in chains of model calculations used to project local climate impacts for adaptation decision support—the case of Baakse Beek

    Science.gov (United States)

    van der Sluijs, Jeroen P.; Arjan Wardekker, J.

    2015-04-01

    In order to enable anticipation and proactive adaptation, local decision makers increasingly seek detailed foresight about regional and local impacts of climate change. To this end, the Netherlands Models and Data-Centre implemented a pilot chain of sequentially linked models to project local climate impacts on hydrology, agriculture and nature under different national climate scenarios for a small region in the east of the Netherlands named Baakse Beek. The chain of models sequentially linked in that pilot includes a (future) weather generator and models of respectively subsurface hydrogeology, ground water stocks and flows, soil chemistry, vegetation development, crop yield and nature quality. These models typically have mismatching time step sizes and grid cell sizes. The linking of these models unavoidably involves the making of model assumptions that can hardly be validated, such as those needed to bridge the mismatches in spatial and temporal scales. Here we present and apply a method for the systematic critical appraisal of model assumptions that seeks to identify and characterize the weakest assumptions in a model chain. The critical appraisal of assumptions presented in this paper has been carried out ex-post. For the case of the climate impact model chain for Baakse Beek, the three most problematic assumptions were found to be: land use and land management kept constant over time; model linking of (daily) ground water model output to the (yearly) vegetation model around the root zone; and aggregation of daily output of the soil hydrology model into yearly input of a so called ‘mineralization reduction factor’ (calculated from annual average soil pH and daily soil hydrology) in the soil chemistry model. Overall, the method for critical appraisal of model assumptions presented and tested in this paper yields a rich qualitative insight in model uncertainty and model quality. It promotes reflectivity and learning in the modelling community, and leads to

  8. Of Otakus and Fansubs: A Critical Look at Anime Online in Light of Current Issues in Copyright Law

    Directory of Open Access Journals (Sweden)

    Jordan S. Hatcher

    2005-12-01

    Full Text Available The advent of digital technology and increased global connectivity has, to put it mildly, caused some ripples for the entertainment industry specifically and copyright law generally. In the aftermath, many are searching for new ways to incorporate the benefits of digital copies and the internet while minimizing the harms. To some, the anime industry and its fans offer examples of how an industry can benefit and even grow from allowing copyright infringement. This article examines the anime industry in-depth with this suggestion in mind and places the industry among current copyright policy debates, such as those suggested by Lawrence Lessig.

  9. Design of a Probe for Strain Sensitivity Studies of Critical Current Densities in SC Wires and Tapes

    Energy Technology Data Exchange (ETDEWEB)

    Dhanaraj, N.; Barzi, E.; Turrioni, D.; Rusy, A.; Lombardo, V.; /Fermilab

    2011-07-01

    The design of a variable-temperature probe used to perform strain sensitivity measurements on LTS wires and HTS wires and tapes is described. The measurements are intended to be performed at liquid helium temperatures (4.2 K). The wire or tape to be measured is wound and soldered on to a helical spring device, which is fixed at one end and subjected to a torque at the free end. The design goal is to be able to achieve {+-} 0.8 % strain in the wire and tape. The probe is designed to carry a current of 2000A.

  10. Executive summary of NIH workshop on the Use and Biology of Energy Drinks: Current Knowledge and Critical Gaps.

    Science.gov (United States)

    Sorkin, Barbara C; Camp, Kathryn M; Haggans, Carol J; Deuster, Patricia A; Haverkos, Lynne; Maruvada, Padma; Witt, Ellen; Coates, Paul M

    2014-10-01

    Sales of energy drinks in the United States reached $12.5 billion in 2012. Emergency department visits related to consumption of these products have increased sharply, and while these numbers remain small relative to product sales, they raise important questions regarding biological and behavioral effects. Although some common ingredients of energy drinks have been extensively studied (e.g., caffeine, B vitamins, sugars, inositol), data on other ingredients (e.g., taurine) are limited. Summarized here are data presented elsewhere in this issue on the prevalence and patterns of caffeine-containing energy drink use, the effects of these products on alertness, fatigue, cognitive functions, sleep, mood, homeostasis, as well as on exercise physiology and metabolism, and the biological mechanisms mediating the observed effects. There are substantial data on the effects of some energy drink ingredients, such as caffeine and sugars, on many of these outcomes; however, even for these ingredients many controversies and gaps remain, and data on other ingredients in caffeine-containing energy drinks, and on ingredient interactions, are sparse. This summary concludes with a discussion of critical gaps in the data and potential next steps.

  11. Droop Control of Solar PV, Grid and Critical Load using Suppressing DC Current Injection Technique without Battery Storage

    Science.gov (United States)

    Dama Mr., Jayachandra; (Mrs. , Lini Mathew, Dr.; Srikanth Mr., G.

    2017-08-01

    This paper presents design of a sustainable solar Photo voltaic system for an Indian cities based residential/community house, integrated with grid, supporting it as supplementary sources, to meet energy demand of domestic loads. The role of renewable energy sources in Distributed Generation (DG) is increasingly being recognized as a supplement and an alternative to large conventional central power supply. Though centralized economic system that solely depends on cities is hampered due to energy deficiency, the use of solar energy in cities is never been tried widely due to technical inconvenience and high installation cost. To mitigate these problems, this paper proposes an optimized design of grid-tied PV system without storage which is suitable for Indian origin as it requires less installallation cost and supplies residential loads when the grid power is unavailable. The energy requirement is mainly fulfilled from PV energy module for critical load of a city located residential house and supplemented by grid/DG for base and peak load. The system has been developed for maximum daily household demand of 50kWp and can be scaled to any higher value as per requirement of individual/community building ranging from 50kWp to 60kWp as per the requirement. A simplified control system model has been developed to optimize and control flow of power from these sources. The simulation work, using MATLAB Simulink software for proposed energy management, has resulted in an optimal yield leading efficient power flow control of proposed system.

  12. The Ghost in the Shell : Local and Remote Forcing of a Coastal Bivalve Inhabiting the Humboldt Current System

    Science.gov (United States)

    Gosselin, M.

    2014-12-01

    The external skeleton of mollusc bivalves, the shell, can furnish a recording of the environmental changes to which the organisms and population are exposed during their lives. The bivalve's growth is subjected to the thermocline variability; which itself is affected by environmental and climatic events. A highly variable environment such as the Humboldt current system (HCS) requires tools capable of recording its variations over a wide range of periodicities. Upwelling, Coastal trapped waves (CTWs), El Niño Southern Oscillation, and Pacific decadal oscillation events contribute to this environmental and climatic variability. The thermocline depth is modified by these different events at their own time-scales (respectively, daily to weekly, intraseasonally, interseasonally to interannually, and on a decadal scale). The thermocline variation translates into changes in Sea surface temperature (SST) and in the qualitative and quantitative productivity of phytoplankton. These two environmental factors are critical to bivalve growth.The sclerochronological (increment width) and sclerochemical (δ18O and δ13C) study consisted on the analysis of the Chilean bivalve Eurhomalea rufa, collected in 2005, as a recorder of the environmental HCS variability. The calibration step identified daily, monthly, and annual marks in the growth patterns of E. rufa. The results confirmed that the thermocline variability mainly drives the bivalve's activity and led to the establishment of a paleotemperature equation. Moreover, periodogram and wavelet analyses exposed the respective impacts of each environmental event from daily to interannual periodicities. In particular, the growth pattern of E. rufa follows SST variability at an intraseasonal periodicity (~ 60 days) which is remotely induced by CTWs. CTWs are generated by Kelvin oceanic waves, which are formed primarily by eastward equatorial Pacific winds (e.g. Shaffer et al. 1997; Montecino and Lange 2009).Sclerochronological studies

  13. Evidence for weak localization effects on the critical magnetic field for the amorphous alloys V/sub 1-//sub x/Si/sub x/

    Energy Technology Data Exchange (ETDEWEB)

    Ousset, J.C.; Rakoto, H.; Broto, J.M.; Dupuis, V.; Durand, J.; Marchal, G.; Pavuna, D.

    1987-04-01

    In this paper we present measurements of the temperature dependence of the upper critical field H/sub c//sub 2/ and of the magnetoresistance for V/sub 1-//sub x/Si/sub x/ superconducting amorphous alloys. Negative deviations from the classical variation of H/sub c//sub 2/ in a dirty superconductor are observed related to a positive magnetoresistance due to weak localization in amorphous systems with finite spin-orbit coupling. These deviations can be qualitatively explained through the model recently developed by Coffey et al.

  14. Fibroblast-like synoviocytes-dependent effector molecules as a critical mediator for rheumatoid arthritis: Current status and future directions.

    Science.gov (United States)

    Ganesan, Ramamoorthi; Rasool, Mahaboobkhan

    2017-01-02

    Rheumatoid arthritis (RA) is a systemic-autoimmune-mediated disease characterized by synovial hyperplasia and progressive destruction of joint. Currently available biological agents and inhibitor therapy that specifically target tumor necrosis factor-α, interleukin 1β (IL-1β), IL-6, T cells, B cells, and subcellular molecules (p38 mitogen-activated protein kinase and janus kinase) cannot facilitate complete remission in all patients and are unable to cure the disease. Therefore, further potent therapeutic targets need to be identified for effective treatment and successful clinical outcomes in patients with RA. Scientific breakthroughs have brought new insights regarding fibroblast-like synoviocytes (FLS), a major constituent of the synovial hyperplasia. These play a pivotal role in RA invading cartilage and bone tissue. Currently there are no effective therapies available that specifically target these aggressive cells. Recent evidences indicate that FLS-dependent effector molecules (toll-like receptors, nodal effector molecules, hypoxia-inducible factor, and IL-17) have emerged as important mediators of RA. In this review, we discuss the pathological features and recent advances in understanding the role of FLS-dependent effector molecules in the disease onset of RA. Pharmacological inhibition of FLS-dependent effector molecules might be a promising option for FLS-targeted therapy in RA.

  15. Depth-dependent critical-current density of melt-processed Y-Ba-Cu-O discs determined by the third-harmonic technique: Surface barrier and intrinsic pinning

    Science.gov (United States)

    Chen, D.-X.; He, T.-F.; Zhang, M.-J.; Wang, S.-S.; Shi, Y.-H.; Cardwell, D. A.

    2016-08-01

    The critical-current density Jc of three Y-Ba-Cu-O (YBCO) discs, each cut from the upper section of a melt-processed single grain, has been determined as a function of the depth from the top (seeded) and bottom surfaces of the sample by a modified version of the inductive third-harmonic technique proposed originally by Mawatari et al. It is shown that local Jc in the vicinity of the bottom surface of the sample is lower than that in the vicinity of the top surface for thicker discs and there are reduced effect of surface barrier and intrinsic pinning and important surface damage. The technique employed is recommended as a tool for detecting the imperfection within superconducting structure in bulk YBCO.

  16. Local SDSS galaxies in the Herschel Stripe 82 survey: a critical assessment of optically derived star formation rates

    Science.gov (United States)

    Rosario, D. J.; Mendel, J. T.; Ellison, S. L.; Lutz, D.; Trump, J. R.

    2016-04-01

    We study a set of 3319 galaxies in the redshift interval 0.04 neglected in existing studies. We also study the capabilities of infrared selection of star-forming galaxies. FIR selection reveals a substantial population of galaxies dominated by cold dust which are missed by the long-wavelength WISE bands. Our results demonstrate that Herschel large-area surveys offer the means to construct large, relatively complete samples of local star-forming galaxies with accurate estimates of SFR that can be used to study the interplay between nuclear activity and star formation.

  17. A study on the counter current and cocurrent annular flow critical heat flux under low flow conditions

    Energy Technology Data Exchange (ETDEWEB)

    Park, Cheol

    1998-02-15

    Empirical and phenomenological investigations have been performed for countercurrent and cocurrent annular flow critical heat fluxes(CHFs) under low flow conditions. The CHF characteristics on finned surfaces were also examined by experiments and analyses for finned and unfinned geometries. A new form of C{sub w}{sup 2} in the Wallis flooding correlation was proposed for a general use in predicting the flooding limited CHF at tubes, annuli and rectangular channels under zero and very low flow conditions. The suggested correlation showed reasonable predictions compared to the measured CHF with an root-mean-square(RMS) error of 18.8%. A physical model for the prediction of a CHF location at a zero inlet flow condition was improved to take into account entrainment from the liquid film and to extend the applicable range to subcooled inlet flow conditions. The improved model showed reasonable agreements with the Katto data, and provided details of the CHF mechanism due to flooding. It was analytically confirmed that the flooding is a triggering mechanism of a countercurrent annular flow CHF under zero and very low flow conditions. It was also revealed that the heat flux effect such as the nucleation induced entrainment in the liquid film should be considered for the analysis of a flooding limited CHF, especially in small L/D geometry. In addition, an attempt was made to predict CHF values by applying the improved model with predetermined CHF locations. The results showed that the predictions by the improved physical model agreed reasonably with the experimental data. Annular flow hydrodynamic models of Whalley, Levy and Katto, which were developed for high flow conditions, were compared with available low flow CHF data to make out the applicability of the models to low flow conditions. As a result, it was found that Katto model, which improved the fault of Whally and Levy models, could be applied to predict low flow CHF with some improvements although the model

  18. Critical review of current animal models of seizures and epilepsy used in the discovery and development of new antiepileptic drugs.

    Science.gov (United States)

    Löscher, Wolfgang

    2011-06-01

    Animal models for seizures and epilepsy have played a fundamental role in advancing our understanding of basic mechanisms underlying ictogenesis and epileptogenesis and have been instrumental in the discovery and preclinical development of novel antiepileptic drugs (AEDs). However, there is growing concern that the efficacy of drug treatment of epilepsy has not substantially improved with the introduction of new AEDs, which, at least in part, may be due to the fact that the same simple screening models, i.e., the maximal electroshock seizure (MES) and s.c. pentylenetetrazole (PTZ) seizure tests, have been used as gatekeepers in AED discovery for >6 decades. It has been argued that these old models may identify only drugs that share characteristics with existing drugs, and are unlikely to have an effect on refractory epilepsies. Indeed, accumulating evidence with several novel AEDs, including levetiracetan, has shown that the MES and PTZ models do not identify all potential AEDs but instead may fail to discover compounds that have great potential efficacy but work through mechanisms not tested by these models. Awareness of the limitations of acute seizure models comes at a critical crossroad. Clearly, preclinical strategies of AED discovery and development need a conceptual shift that is moving away from using models that identify therapies for the symptomatic treatment of epilepsy to those that may be useful for identifying therapies that are more effective in the refractory population and that may ultimately lead to an effective cure in susceptible individuals by interfering with the processes underlying epilepsy. To realize this goal, the molecular mechanisms of the next generation of therapies must necessarily evolve to include targets that contribute to epileptogenesis and pharmacoresistance in relevant epilepsy models.

  19. DSCR2, a Down syndrome critical region protein, is localized to the endoplasmic reticulum of mammalian cells

    Directory of Open Access Journals (Sweden)

    PA Possik

    2009-06-01

    Full Text Available We used immunocytochemical and fluorescence assays to investigate the subcellular location of the protein encoded by Down syndrome critical region gene 2 (DSCR2 in transfected cells. It was previously suggested that DSCR2 is located in the plasma membrane as an integral membrane protein. Interestingly, we observed this protein in the endoplasmic reticulum (ER of cells.We also studied whether the truncated forms of DSCR2 showed different subcellular distributions. Our observations indicate that DSCR2 probably is not inserted into the membrane of the endoplasmic reticulum since the fragments lacking the predicted transmembrane (TM helices remained associated with the ER. Our analyses suggest that, although DSCR2 is associated with the endoplasmic reticulum, it is not an integral membrane protein and it is maintained on the cytoplasmic side of the ER by indirect interaction with the ER membrane or with another protein.

  20. Relationships of sex steroid hormone levels in benign and cancerous breast tissue and blood: A critical appraisal of current science.

    Science.gov (United States)

    Stanczyk, Frank Z; Mathews, Brett W; Sherman, Mark E

    2015-07-01

    cancer patients are consistent with an obesity-inflammation-aromatase axis occurring locally in breast tissue. The controversies regarding the source of intratumoral estrogens in the breast are summarized. Copyright © 2015 Elsevier Ltd. All rights reserved.