Theory of flux cutting and flux transport at the critical current of a type-II superconducting cylindrical wire

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clem, John R.

2011-02-17

I introduce a critical-state theory incorporating both flux cutting and flux transport to calculate the magnetic-field and current-density distributions inside a type-II superconducting cylinder at its critical current in a longitudinal applied magnetic field. The theory is an extension of the elliptic critical-state model introduced by Romero-Salazar and Perez-Rodriguez. The vortex dynamics depend in detail on two nonlinear effective resistivities for flux cutting ({rho}{parallel}) and flux flow ({rho}{perpendicular}), and their ratio r = {rho}{parallel}/{rho}{perpendicular}. When r < 1, the low relative efficiency of flux cutting in reducing the magnitude of the internal magnetic-flux density leads to a paramagnetic longitudinal magneticmore » moment. As a model for understanding the experimentally observed interrelationship between the critical currents for flux cutting and depinning, I calculate the forces on a helical vortex arc stretched between two pinning centers when the vortex is subjected to a current density of arbitrary angle {phi}. Simultaneous initiation of flux cutting and flux transport occurs at the critical current density J{sub c}({phi}) that makes the vortex arc unstable.« less

Theory of flux cutting and flux transport at the critical current of a type-II superconducting cylindrical wire

NASA Astrophysics Data System (ADS)

Clem, John R.

2011-06-01

I introduce a critical-state theory incorporating both flux cutting and flux transport to calculate the magnetic-field and current-density distributions inside a type-II superconducting cylinder at its critical current in a longitudinal applied magnetic field. The theory is an extension of the elliptic critical-state model introduced by Romero-Salazar and Pérez-Rodríguez. The vortex dynamics depend in detail on two nonlinear effective resistivities for flux cutting (ρ∥) and flux flow (ρ⊥), and their ratio r=ρ∥/ρ⊥. When r<1, the low relative efficiency of flux cutting in reducing the magnitude of the internal magnetic-flux density leads to a paramagnetic longitudinal magnetic moment. As a model for understanding the experimentally observed interrelationship between the critical currents for flux cutting and depinning, I calculate the forces on a helical vortex arc stretched between two pinning centers when the vortex is subjected to a current density of arbitrary angle ϕ. Simultaneous initiation of flux cutting and flux transport occurs at the critical current density Jc(ϕ) that makes the vortex arc unstable.

Double disordered YBCO coated conductors of industrial scale: high currents in high magnetic field

NASA Astrophysics Data System (ADS)

Abraimov, D.; Ballarino, A.; Barth, C.; Bottura, L.; Dietrich, R.; Francis, A.; Jaroszynski, J.; Majkic, G. S.; McCallister, J.; Polyanskii, A.; Rossi, L.; Rutt, A.; Santos, M.; Schlenga, K.; Selvamanickam, V.; Senatore, C.; Usoskin, A.; Viouchkov, Y. L.

2015-11-01

A significant increase of critical current in high magnetic field, up to 31 T, was recorded in long tapes manufactured by employing a double-disorder route. In a double-disordered high-temperature superconductor (HTS), a superimposing of intrinsic and extrinsic disorder takes place in a way that (i) the intrinsic disorder is caused by local stoichiometry deviations that lead to defects of crystallinity that serve as pining centers in the YBa2Cu3O x-δ matrix and (ii) the extrinsic disorder is introduced via embedded atoms or particles of foreign material (e.g. barium zirconate), which create a set of lattice defects. We analyzed possible technological reasons for this current gain. The properties of these tapes over a wider field-temperature range as well as field anisotropy were also studied. Record values of critical current as high as 309 A at 31 T, 500 A at 18 Tm and 1200 A at 5 T were found in 4 mm wide tape at 4.2 K and B perpendicular to tape surface. HTS layers were processed in medium-scale equipment that allows a maximum batch length of 250 m while 22 m long batches were provided for investigation. Abnormally high ratios (up to 10) of critical current density measured at 4.2 K, 19 T to critical current density measured at 77 K, self-field were observed in tapes with the highest in-field critical current. Anisotropy of the critical current as well as angular dependences of n and α values were investigated. The temperature dependence of critical current is presented for temperatures between 4.2 and 40 K. Prospects for the suppression of the dog-bone effect by Cu plating and upscale of processing chain to >500 m piece length are discussed.

Vortices in high-performance high-temperature superconductors

DOE PAGES

Kwok, Wai-Kwong; Welp, Ulrich; Glatz, Andreas; ...

2016-09-21

The behavior of vortex matter in high-temperature superconductors (HTS) controls the entire electromagnetic response of the material, including its current carrying capacity. In this paper, we review the basic concepts of vortex pinning and its application to a complex mixed pinning landscape to enhance the critical current and to reduce its anisotropy. We focus on recent scientific advances that have resulted in large enhancements of the in-field critical current in state-of-the-art second generation (2G) YBCO coated conductors and on the prospect of an isotropic, high-critical current superconductor in the iron-based superconductors. Finally, we discuss an emerging new paradigm of criticalmore » current by design—a drive to achieve a quantitative correlation between the observed critical current density and mesoscale mixed pinning landscapes by using realistic input parameters in an innovative and powerful large-scale time dependent Ginzburg–Landau approach to simulating vortex dynamics.« less

Superconducting magnetic coil

DOEpatents

Aized, Dawood; Schwall, Robert E.

1999-06-22

A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil.

Superconducting magnetic coil

DOEpatents

Aized, Dawood; Schwall, Robert E.

1996-06-11

A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil.

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

NASA Technical Reports Server (NTRS)

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.

The transverse stress effect on the critical current of jelly-roll multifilamentary Nb sub 3 Al wires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeritis, D.; Iwasa, Y.; Ando, T.

This paper reports on experiments conducted to determine the effect of transverse compressive stress (TCS) on the critical current of jelly-roll multifilamentary Nb{sub 3}Al wire (0.8-mm dia.) for magnetic flux densities up to 12 T. For comparison, identical experiments were performed for bronze-process Ti-alloyed multifilamentary Nb{sub 3}Sn wire (1.0-mm dia.). Although the unstressed critical current density of Nb{sub 3}Al was inferior to that of (NbTi){sub 3}Sn at high fields, under applied TCS Nb{sub 3}Al exhibited less critical current degradation than (NbTi){sub 3}Sn. For example, at 12 T and 150 MPa, TCS-induced critical current degradation was approximately 20% for Nb{sub 3}Al,more » whereas it was approximately 65% for (NbTi){sub 3}Sn. There is optimism that Nb{sub 3}Al will evolve into a useful superconductor for large-scale, high-field applications.« less

Crack problem in superconducting cylinder with exponential distribution of critical-current density

NASA Astrophysics Data System (ADS)

Zhao, Yufeng; Xu, Chi; Shi, Liang

2018-04-01

The general problem of a center crack in a long cylindrical superconductor with inhomogeneous critical-current distribution is studied based on the extended Bean model for zero-field cooling (ZFC) and field cooling (FC) magnetization processes, in which the inhomogeneous parameter η is introduced for characterizing the critical-current density distribution in inhomogeneous superconductor. The effect of the inhomogeneous parameter η on both the magnetic field distribution and the variations of the normalized stress intensity factors is also obtained based on the plane strain approach and J-integral theory. The numerical results indicate that the exponential distribution of critical-current density will lead a larger trapped field inside the inhomogeneous superconductor and cause the center of the cylinder to fracture more easily. In addition, it is worth pointing out that the nonlinear field distribution is unique to the Bean model by comparing the curve shapes of the magnetization loop with homogeneous and inhomogeneous critical-current distribution.

Enhanced critical currents in (Gd,Y)Ba2Cu3Ox superconducting tapes with high levels of Zr addition

NASA Astrophysics Data System (ADS)

Selvamanickam, V.; Chen, Y.; Shi, T.; Liu, Y.; Khatri, N. D.; Liu, J.; Yao, Y.; Xiong, X.; Lei, C.; Soloveichik, S.; Galstyan, E.; Majkic, G.

2013-03-01

The critical current and structural properties of (Gd,Y)BaCuO tapes made by metal organic chemical vapor deposition (MOCVD) with Zr addition levels up to 30 at.% have been investigated. The reduction in critical current beyond the previously optimized Zr addition level of 7.5 at.% was found to be due to structural deterioration of the (Gd,Y)Ba2Cu3Ox film. By a modified MOCVD process, enhanced critical current densities have been achieved with high levels of Zr addition, including 3.83 MA cm-2 in 15 at.% Zr-added 1.1 μm thick film at 77 K in zero magnetic field. Critical currents as high as 1072 A/12 mm have been reached in (Gd,Y)BaCuO tapes with 15 at.% Zr addition at 30 K in a field of 3 T applied perpendicular to the tape, corresponding to a pinning force value of 268 GN m-3. The enhanced critical currents achievable with a high density of nanoscale defects by employing high levels of second-phase additions enable the performance targets needed for the use of HTS tapes in coil applications involving high magnetic fields at temperatures below 50 K to be met.

Effect of fatigue loading on critical current in stainless steel-laminated DI-BSCCO superconducting composite tape

NASA Astrophysics Data System (ADS)

Hojo, M.; Osawa, K.; Adachi, T.; Inoue, Y.; Osamura, K.; Ochiai, S.; Ayai, N.; Hayashi, K.

2010-11-01

Tensile strain tolerance of the critical current in (Bi,Pb)2Sr2Ca2Cu3Ox (Bi2223) composite superconductor is dramatically improved when the tape is laminated with stainless steel. For practical applications, it is important to understand whether this reinforcement by lamination is effective under fatigue loading. In the present study, we carried out fatigue tests in LN2 and measured the critical current at the specific fatigue cycles to clarify the strain tolerance of the critical current in stainless steel-laminated drastically innovative Bi2223 (DI-BSCCO®) tapes. The fatigue tests were carried out using a computer-controlled 10 kN servo-hydraulic fatigue testing machine with a load cell capacity of 2.5 kN. Tests under static loading showed that the irreversible stress at which the critical current is reduced by 1% from the original value (tensile stress at Ic/Ic0 = 0.99) was 315 MPa when measured at unloading state. The present fatigue tests results indicated that the critical current was maintained at over 98% of the original value at unloading state after stress cycles of 106 when the static irreversible stress was selected as the maximum stress under fatigue loading. Thus, laminated DI-BSCCO tapes showed excellent mechanical properties even under fatigue loading.

Apparatus and method for critical current measurements

DOEpatents

Martin, Joe A.; Dye, Robert C.

1992-01-01

An apparatus for the measurement of the critical current of a superconductive sample, e.g., a clad superconductive sample, the apparatus including a conductive coil, a means for maintaining the coil in proximity to a superconductive sample, an electrical connection means for passing a low amplitude alternating current through the coil, a cooling means for maintaining the superconductive sample at a preselected temperature, a means for passing a current through the superconductive sample, and, a means for monitoring reactance of the coil, is disclosed, together with a process of measuring the critical current of a superconductive material, e.g., a clad superconductive material, by placing a superconductive material into the vicinity of the conductive coil of such an apparatus, cooling the superconductive material to a preselected temperature, passing a low amplitude alternating current through the coil, the alternating current capable of generating a magnetic field sufficient to penetrate, e.g., any cladding, and to induce eddy currents in the superconductive material, passing a steadily increasing current through the superconductive material, the current characterized as having a different frequency than the alternating current, and, monitoring the reactance of the coil with a phase sensitive detector as the current passed through the superconductive material is steadily increased whereby critical current of the superconductive material can be observed as the point whereat a component of impedance deviates.

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

NASA Astrophysics Data System (ADS)

Shahabuddin, Mohammed; Alzayed, Nasser S.; Oh, Sangjun; Choi, Seyong; Maeda, Minoru; Hata, Satoshi; Shimada, Yusuke; Hossain, Md Shahriar Al; Kim, Jung Ho

2014-01-01

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.

Influence of field dependent critical current density on flux profiles in high Tc superconductors

NASA Technical Reports Server (NTRS)

Takacs, S.

1990-01-01

The field distribution for superconducting cylinders and slabs with field dependent critical current densities in combined DC and AC magnetic fields and the corresponding magnetic fluxes are calculated. It is shown that all features of experimental magnetic-field profile measurements can be explained in the framework of field dependent critical current density. Even the quantitative agreement between the experimental and theoretical results using Kim's model is very good.

Superconducting magnetic coil

DOEpatents

Aized, D.; Schwall, R.E.

1999-06-22

A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil. 15 figs.

The Critical Events Interview Manual.

ERIC Educational Resources Information Center

Avery, Donna M.; Taubert, Alexis

This guide for counselors describes the Critical Events Interview (CEI), a new counseling technique designed to be used with women in transition. The concept of critical events and their influence on adult development is described and the history and current status of the CEI are reviewed, along with current results of CEI evaluations and…

A Needs Assessment of Brain Death Education in Pediatric Critical Care Medicine Fellowships.

PubMed

Ausmus, Andrew M; Simpson, Pippa M; Zhang, Liyun; Petersen, Tara L

2018-04-12

To assess the current training in brain death examination provided during pediatric critical care medicine fellowship. Internet-based survey. United States pediatric critical care medicine fellowship programs. Sixty-four pediatric critical care medicine fellowship program directors and 230 current pediatric critical care medicine fellows/recent graduates were invited to participate. Participants were asked demographic questions related to their fellowship programs, training currently provided at their fellowship programs, previous experience with brain death examinations (fellows/graduates), and perceptions regarding the adequacy of current training. Twenty-nine program directors (45%) and 91 current fellows/graduates (40%) responded. Third-year fellows reported having performed a median of five examinations (interquartile range, 3-6). On a five-point Likert scale, 93% of program directors responded they "agree" or "strongly agree" that their fellows receive enough instruction on performing brain death examinations compared with 67% of fellows and graduates (p = 0.007). The responses were similar when asked about opportunity to practice brain death examinations (90% vs 54%; p < 0.001). In a regression tree analysis, number of brain death examinations performed was the strongest predictor of trainee satisfaction. Both fellows and program directors preferred bedside demonstration or simulation as educational modalities to add to the fellowship curriculum. Pediatric critical care medicine fellows overall perform relatively few brain death examinations during their training. Pediatric critical care medicine fellows and program directors disagree in their perceptions of the current training in brain death examination, with fellows perceiving a need for increased training. Both program directors and fellows prefer additional training using bedside demonstration or simulation. Since clinical exposure to brain death examinations is variable, adding simulated brain death examinations to the pediatric critical care medicine fellowship curriculum could help standardize the experience.

The Reduction of the Critical Currents in Nb3Sn Cables under Transverse Loads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Oort, J.M.; Scanlan, R.M.; Weijers, H.W.

1992-08-01

The degradation of the critical current of impregnated Rutherford type Nb{sub 3}Sn cables is investigated as a function of the applied transverse load and magnetic field. The cable is made of TWCA modified jelly-roll type strand material and has a keystone angle of 1.0 degree. The voltage-current characteristics are determined for the magnetic field ranging from 2 to 11 tesla and transverse pressure up to 250 MPa on the cable surface. It is found that the 48-strand cable, made of strands with 6 elements in the matrix, shows a larger critical current degradation than the 26-strand cable with 36 elementsmore » per strand. The global degradation of the 48-strand cable is 63% at 150 MPa, and 40% at 150 MPa for the 26-strand cable. Micro-analysis of the cross-section shows permanent damage to the sharp edge of the cable. The influence of the keystone angle on the critical-current degradation is currently under investigation.« less

Enhancing superconducting critical current by randomness

DOE PAGES

Wang, Y. L.; Thoutam, L. R.; Xiao, Z. L.; ...

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, wheremore » 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.« less

Development of a 10 m quasi-isotropic strand assembled from 2G wires

NASA Astrophysics Data System (ADS)

Kan, Changtao; Wang, Yinshun; Hou, Yanbing; Li, Yan; Zhang, Han; Fu, Yu; Jiang, Zhe

2018-03-01

Quasi-isotropic strands made of second generation (2G) high temperature superconducting (HTS) wires are attractive to applications of high-field magnets at low temperatures and power transmission cables at liquid nitrogen temperature in virtue of their high current carrying capability and well mechanical property. In this contribution, a 10 m length quasi-isotropic strand is manufactured and successfully tested in liquid nitrogen to verify the feasibility of an industrial scale production of the strand by the existing cabling technologies. The strand with copper sheath consists of 72 symmetrically assembled 2G wires. The uniformity of critical properties of long quasi-isotropic strands, including critical current and n-value, is very important for their using. Critical currents as well as n-values of the strand are measured every 1 m respectively and compared with the simulation results. Critical current and n-value of the strand are calculated basing on the self-consistent model solved by the finite element method (FEM). Effects of self-field on the critical current and n-value distributions in wires of the strand are analyzed in detail. The simulation results show good agreement with the experimental data and the 10 m quasi-isotropic strand has good critical properties uniformity.

Higher Education: A Critical Business.

ERIC Educational Resources Information Center

Barnett, Ronald

Current concepts of critical thinking need to be reconstrued into the much broader concept of "critical being" and applied to higher education. Under this construct, critical persons (students) become more than just critical thinkers; they engage critically with the world and with themselves; they not only reflect critically on…

Magnetic field oscillations of the critical current in long ballistic graphene Josephson junctions

NASA Astrophysics Data System (ADS)

Rakyta, Péter; Kormányos, Andor; Cserti, József

2016-06-01

We study the Josephson current in long ballistic superconductor-monolayer graphene-superconductor junctions. As a first step, we have developed an efficient computational approach to calculate the Josephson current in tight-binding systems. This approach can be particularly useful in the long-junction limit, which has hitherto attracted less theoretical interest but has recently become experimentally relevant. We use this computational approach to study the dependence of the critical current on the junction geometry, doping level, and an applied perpendicular magnetic field B . In zero magnetic field we find a good qualitative agreement with the recent experiment of M. Ben Shalom et al. [Nat. Phys. 12, 318 (2016), 10.1038/nphys3592] for the length dependence of the critical current. For highly doped samples our numerical calculations show a broad agreement with the results of the quasiclassical formalism. In this case the critical current exhibits Fraunhofer-like oscillations as a function of B . However, for lower doping levels, where the cyclotron orbit becomes comparable to the characteristic geometrical length scales of the system, deviations from the results of the quasiclassical formalism appear. We argue that due to the exceptional tunability and long mean free path of graphene systems a new regime can be explored where geometrical and dynamical effects are equally important to understand the magnetic field dependence of the critical current.

Critical Decay Index at the Onset of Solar Eruptions

NASA Astrophysics Data System (ADS)

Zuccarello, F. P.; Aulanier, G.; Gilchrist, S. A.

2015-12-01

Magnetic flux ropes are topological structures consisting of twisted magnetic field lines that globally wrap around an axis. The torus instability model predicts that a magnetic flux rope of major radius R undergoes an eruption when its axis reaches a location where the decay index -d({ln}{B}{ex})/d({ln}R) of the ambient magnetic field Bex is larger than a critical value. In the current-wire model, the critical value depends on the thickness and time evolution of the current channel. We use magnetohydrodynamic simulations to investigate whether the critical value of the decay index at the onset of the eruption is affected by the magnetic flux rope’s internal current profile and/or by the particular pre-eruptive photospheric dynamics. The evolution of an asymmetric, bipolar active region is driven by applying different classes of photospheric motions. We find that the critical value of the decay index at the onset of the eruption is not significantly affected by either the pre-erupitve photospheric evolution of the active region or the resulting different magnetic flux ropes. As in the case of the current-wire model, we find that there is a “critical range” [1.3-1.5], rather than a “critical value” for the onset of the torus instability. This range is in good agreement with the predictions of the current-wire model, despite the inclusion of line-tying effects and the occurrence of tether-cutting magnetic reconnection.

Eddy current technique for predicting burst pressure

DOEpatents

Petri, Mark C.; Kupperman, David S.; Morman, James A.; Reifman, Jaques; Wei, Thomas Y. C.

2003-01-01

A signal processing technique which correlates eddy current inspection data from a tube having a critical tubing defect with a range of predicted burst pressures for the tube is provided. The method can directly correlate the raw eddy current inspection data representing the critical tubing defect with the range of burst pressures using a regression technique, preferably an artificial neural network. Alternatively, the technique deconvolves the raw eddy current inspection data into a set of undistorted signals, each of which represents a separate defect of the tube. The undistorted defect signal which represents the critical tubing defect is related to a range of burst pressures utilizing a regression technique.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Selvamanickam, V; Chen, Y; Shi, T

The critical current and structural properties of (Gd,Y)BaCuO tapes made by metal organic chemical vapor deposition (MOCVD) with Zr addition levels up to 30 at.% have been investigated. The reduction in critical current beyond the previously optimized Zr addition level of 7.5 at.% was found to be due to structural deterioration of the (Gd,Y)Ba2Cu3Ox film. By a modified MOCVD process,enhanced critical current densities have been achieved with high levels of Zr addition,including 3.83 MA cm(-2) in 15 at.% Zr- added 1.1 mu m thick film at 77 K in zero magnetic field. Critical currents as high as 1072 A/ 12more » mm have been reached in (Gd,Y) BaCuO tapes with 15 at.% Zr addition at 30 K in a field of 3 T applied perpendicular to the tape,corresponding to a pinning force value of 268 GN m(-3). The enhanced critical currents achievable with a high density of nanoscale defects by employing high levels of second- phase additions enable the performance targets needed for the use of HTS tapes in coil applications involving high magnetic fields at temperatures below 50 K to be met.« less

Correlations between critical current density, j(sub c), critical temperature, T(sub c),and structural quality of Y1B2Cu3O(7-x) thin superconducting films

NASA Technical Reports Server (NTRS)

Chrzanowski, J.; Xing, W. B.; Atlan, D.; Irwin, J. C.; Heinrich, B.; Cragg, R. A.; Zhou, H.; Angus, V.; Habib, F.; Fife, A. A.

1995-01-01

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) LaAlO3 single crystals. Distinct maxima in j(sub c) as a function of the linewidths of the (00 l) 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 approachingthat 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 ND 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(exp 9)/sq cm.

Excess current experiment on YBCO tape conductor with metal stabilized layer

NASA Astrophysics Data System (ADS)

Tasaki, Kenji; Yazawa, Takashi; Ono, Michitaka; Kuriyama, Toru

2006-06-01

Excess current experiments were performed using YBCO tape conductors with a metal stabilized layer on the superconducting layer. The purpose of this research is to obtain the stable criteria of energy dissipation when YBCO tape is forced to flow excess current higher than its critical current. This situation should be considered in power applications. In the experiments short-length samples were immersed in liquid nitrogen and several cycles of 50Hz sinusoidal current were supplied to the samples by an induction voltage regulator. The critical current of the samples was about 110 A. With pulse length as long as 60 ms, YBCO tapes were able to be energized up to twelve times as the critical current without electrical or mechanical deformation. Prior to the excess current experiments, temperature dependency of resistance of the sample was measured so that the temperature rise was estimated by the generated resistance. It is found that YBCO tapes with a copper stabilized layer can be transiently heated to over 400K without degradation.

The influence of winding direction of two-layer HTS DC cable on the critical current

NASA Astrophysics Data System (ADS)

Vyatkin, V. S.; Kashiwagi, K.; Ivanov, Y. V.; Otabe, E. S.; Yamaguchi, S.

2017-09-01

The design of twist pitch and direction of winding in multilayer HTS coaxial cable is important. For HTS AC transmitting cables, the main condition of twist pitch is the balance of inductances of each layer for providing the current balance between layers. In this work, the finite element method analysis for the coaxial cables with both same and opposite directions winding is used to calculate magnetic field distribution, and critical current of the cable is estimated. It was found that the critical current of the cable with same direction winding is about 10 percent higher than that in the case of the cable with the opposite direction winding.

Critical Education, Critical Pedagogies, Marxist Education in the United States

ERIC Educational Resources Information Center

Foley, Jean Ann; Morris, Doug; Gounari, Panayota; Agostinone-Wilson, Faith

2015-01-01

As critical pedagogy becomes more mainstream on the educational landscape in the United States, it is important to revisit the original tenets of critical pedagogy and explore their current manifestations. Since the beginning of "criticalism" from the theoretical/foundational work of the Frankfurt School of Critical Social Theory,…

Critical current studies of a HTS rectangular coil

NASA Astrophysics Data System (ADS)

Zhong, Z.; Chudy, M.; Ruiz, H. S.; Zhang, X.; Coombs, T.

2017-05-01

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.

RAPID COMMUNICATION: Effect of strain, magnetic field and field angle on the critical current density of Y Ba2Cu3O7-δ coated conductors

NASA Astrophysics Data System (ADS)

van der Laan, D. C.; Ekin, J. W.; Douglas, J. F.; Clickner, C. C.; Stauffer, T. C.; Goodrich, L. F.

2010-07-01

A large, magnetic-field-dependent, reversible reduction in critical current density with axial strain in Y Ba2Cu3O7-δ coated conductors at 75.9 K has been measured. This effect may have important implications for the performance of Y Ba2Cu3O7-δ coated conductors in applications where the conductor experiences large stresses in the presence of a magnetic field. Previous studies have been performed only under tensile strain and could provide only a limited understanding of the in-field strain effect. We now have constructed a device for measuring the critical current density as a function of axial compressive and tensile strain and applied magnetic field as well as magnetic field angle, in order to determine the magnitude of this effect and to create a better understanding of its origin. The reversible reduction in critical current density with strain becomes larger with increasing magnetic field at all field angles. At 76 K the critical current density is reduced by about 30% at - 0.5% strain when a magnetic field of 5 T is applied parallel to the c-axis of the conductor or 8 T is applied in the ab-plane, compared to a reduction of only 13% in self-field. Differences in the strain response of the critical current density at various magnetic field angles indicate that the pinning mechanisms in Y Ba2Cu3O7-δ coated conductors are uniquely affected by strain. Contribution of NIST, not subject to US copyright.

Spatial characterization of the edge barrier in wide superconducting films

NASA Astrophysics Data System (ADS)

Sivakov, A. G.; Turutanov, O. G.; Kolinko, A. E.; Pokhila, A. S.

2018-03-01

The current-induced destruction of superconductivity is discussed in wide superconducting thin films, whose width is greater than the magnetic field penetration depth, in weak magnetic fields. Particular attention is paid to the role of the boundary potential barrier (the Bin-Livingston barrier) in critical state formation and detection of the edge responsible for this critical state with different mutual orientations of external perpendicular magnetic field and transport current. Critical and resistive states of the film were visualized using the space-resolving low-temperature laser scanning microscopy (LTLSM) method, which enables detection of critical current-determining areas on the film edges. Based on these observations, a simple technique was developed for investigation of the critical state separately at each film edge, and for the estimation of residual magnetic fields in cryostats. The proposed method only requires recording of the current-voltage characteristics of the film in a weak magnetic field, thus circumventing the need for complex LTLSM techniques. Information thus obtained is particularly important for interpretation of studies of superconducting film single-photon light emission detectors.

Superconducting current injection transistor with very high critical-current-density edge-junctions

NASA Astrophysics Data System (ADS)

van Zeghbroeck, B. J.

1985-03-01

A Superconducting Current Injection Transistor (Super-CIT) was fabricated with very high critical current-density edge-junctions. The junctions have a niobium base electrode and a lead-alloy counter electrode. The length of the junctions is 30 microns and the critical-current density is 190KA/sq cm. The Super-CIT has a current gain of 2, a large signal transresistance of 100 mV/A, and the turn-on delay, inferred from the junction resonance, is 7ps. The power dissipation is 3.5 microwatts and the power-delay product is 24.5aJ. Gap reduction due to heating was observed, limiting the maximum power dissipation per unit length to 1.1 microwatt/micron. Compared to lead-alloy Super-CITs, the device is five times smaller, three times faster, and has a three times larger output voltage. The damping resistor and the contact junction could also be eliminated.

Assessing Students' Critical Thinking Performance: Urging for Measurements Using Multi-Response Format

ERIC Educational Resources Information Center

Ku, Kelly Y. L.

2009-01-01

The current paper discusses ambiguities in critical thinking assessment. The paper first reviews the components of critical thinking. It then discusses the features and issues of commonly used critical thinking tests and to what extend they are made compatible to the conceptualization of critical thinking. The paper argues that critical thinking…

On-line and real-time diagnosis method for proton membrane fuel cell (PEMFC) stack by the superposition principle

NASA Astrophysics Data System (ADS)

Lee, Young-Hyun; Kim, Jonghyeon; Yoo, Seungyeol

2016-09-01

The critical cell voltage drop in a stack can be followed by stack defect. A method of detecting defective cell is the cell voltage monitoring. The other methods are based on the nonlinear frequency response. In this paper, the superposition principle for the diagnosis of PEMFC stack is introduced. If critical cell voltage drops exist, the stack behaves as a nonlinear system. This nonlinearity can explicitly appear in the ohmic overpotential region of a voltage-current curve. To detect the critical cell voltage drop, a stack is excited by two input direct test-currents which have smaller amplitude than an operating stack current and have an equal distance value from the operating current. If the difference between one voltage excited by a test current and the voltage excited by a load current is not equal to the difference between the other voltage response and the voltage excited by the load current, the stack system acts as a nonlinear system. This means that there is a critical cell voltage drop. The deviation from the value zero of the difference reflects the grade of the system nonlinearity. A simulation model for the stack diagnosis is developed based on the SPP, and experimentally validated.

Effects of high-energy proton irradiation on the superconducting properties of Fe(Se,Te) thin films

NASA Astrophysics Data System (ADS)

Sylva, G.; Bellingeri, E.; Ferdeghini, C.; Martinelli, A.; Pallecchi, I.; Pellegrino, L.; Putti, M.; Ghigo, G.; Gozzelino, L.; Torsello, D.; Grimaldi, G.; Leo, A.; Nigro, A.; Braccini, V.

2018-05-01

In this paper we explore the effects of 3.5 MeV proton irradiation on Fe(Se,Te) thin films grown on CaF2. In particular, we carry out an experimental investigation with different irradiation fluences up to 7.30 · 1016 cm‑2 and different proton implantation depths, in order to clarify whether and to what extent the critical current is enhanced or suppressed, what are the effects of irradiation on the critical temperature, resistivity, and critical magnetic fields, and finally what is the role played by the substrate in this context. We find that the effect of irradiation on superconducting properties is generally small compared to the case of other iron-based superconductors. The irradiation effect is more evident on the critical current density Jc, while it is minor on the transition temperature Tc, normal state resistivity ρ, and on the upper critical field Hc2 up to the highest fluences explored in this work. In more detail, our analysis shows that when protons implant in the substrate far from the superconducting film, the critical current can be enhanced up to 50% of the pristine value at 7 T and 12 K; meanwhile, there is no appreciable effect on critical temperature and critical fields together with a slight decrease in resistivity. On the contrary, when the implantation layer is closer to the film–substrate interface, both critical current and temperature show a decrease accompanied by an enhancement of the resistivity and lattice strain. This result evidences that possible modifications induced by irradiation in the substrate may affect the superconducting properties of the film via lattice strain. The robustness of the Fe(Se,Te) system to irradiation-induced damage makes it a promising compound for the fabrication of magnets in high-energy accelerators.

Criticality and turbulence in a resistive magnetohydrodynamic current sheet

NASA Astrophysics Data System (ADS)

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.

Criticality and turbulence in a resistive magnetohydrodynamic current sheet.

PubMed

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.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prodan, Emil, E-mail: prodan@yu.edu; Bellissard, Jean

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 amore » critical point and confirm the theoretical predictions.« less

A "Networked-Hutong Siwei of Critiques" for Critical Teacher Education

ERIC Educational Resources Information Center

Qi, Jing

2014-01-01

This paper offers a conceptual basis for refashioning the formulation of critical teacher education. It argues that current critical teacher education is uncritically constructed upon key theoretical departures from critical theories. Drawing on Boltanski's critique of critical theories, the paper examines the ways these theoretical departures…

Feminist Literary Criticism; Explorations in Theory.

ERIC Educational Resources Information Center

Donovan, Josephine, Ed.

A collection of five essays (plus preface and afterword) by noted feminist critics, this book provides an overview of the existing body of feminist literary criticism in order to promote an understanding of the issues feminist critics are currently discussing among themselves and with other critics. A theoretical framework for understanding this…

Critical experiments at Sandia National Laboratories : technical meeting on low-power critical facilities and small reactors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harms, Gary A.; Ford, John T.; Barber, Allison Delo

2010-11-01

Sandia National Laboratories (SNL) has conducted radiation effects testing for the Department of Energy (DOE) and other contractors supporting the DOE since the 1960's. Over this period, the research reactor facilities at Sandia have had a primary mission to provide appropriate nuclear radiation environments for radiation testing and qualification of electronic components and other devices. The current generation of reactors includes the Annular Core Research Reactor (ACRR), a water-moderated pool-type reactor, fueled by elements constructed from UO2-BeO ceramic fuel pellets, and the Sandia Pulse Reactor III (SPR-III), a bare metal fast burst reactor utilizing a uranium-molybdenum alloy fuel. The SPR-IIImore » is currently defueled. The SPR Facility (SPRF) has hosted a series of critical experiments. A purpose-built critical experiment was first operated at the SPRF in the late 1980's. This experiment, called the Space Nuclear Thermal Propulsion Critical Experiment (CX), was designed to explore the reactor physics of a nuclear thermal rocket motor. This experiment was fueled with highly-enriched uranium carbide fuel in annular water-moderated fuel elements. The experiment program was completed and the fuel for the experiment was moved off-site. A second critical experiment, the Burnup Credit Critical Experiment (BUCCX) was operated at Sandia in 2002. The critical assembly for this experiment was based on the assembly used in the CX modified to accommodate low-enriched pin-type fuel in water moderator. This experiment was designed as a platform in which the reactivity effects of specific fission product poisons could be measured. Experiments were carried out on rhodium, an important fission product poison. The fuel and assembly hardware for the BUCCX remains at Sandia and is available for future experimentation. The critical experiment currently in operation at the SPRF is the Seven Percent Critical Experiment (7uPCX). This experiment is designed to provide benchmark reactor physics data to support validation of the reactor physics codes used to design commercial reactor fuel elements in an enrichment range above the current 5% enrichment cap. A first set of critical experiments in the 7uPCX has been completed. More experiments are planned in the 7uPCX series. The critical experiments at Sandia National Laboratories are currently funded by the US Department of Energy Nuclear Criticality Safety Program (NCSP). The NCSP has committed to maintain the critical experiment capability at Sandia and to support the development of a critical experiments training course at the facility. The training course is intended to provide hands-on experiment experience for the training of new and re-training of practicing Nuclear Criticality Safety Engineers. The current plans are for the development of the course to continue through the first part of fiscal year 2011 with the development culminating is the delivery of a prototype of the course in the latter part of the fiscal year. The course will be available in fiscal year 2012.« less

Effects of repeated bending load at room temperature for composite Nb3Sn wires

NASA Astrophysics Data System (ADS)

Awaji, Satoshi; Watanabe, Kazuo; Katagiri, Kazumune

2003-09-01

In order to realize a react and wind (R&W) method for Nb3Sn wires, the influences of a bending load at room temperature are investigated. Usually, the superconducting wires undergo bending loads at room temperature repeatedly during winding and insulation processes. We define these bending loads as 'pre-bending' treatments. We applied the pre-bending strain of 0 and 0.5% to the highly strengthened CuNb/(Nb, Ti)3Sn wires, and measured the stress/strain properties and critical currents. The improvements of stress dependence of normalized critical current and the increase of the maximum critical current by the pre-bending treatments were found. The model based on the distribution of the local tensile strain as a bending strain describes the experimental results well without the increase of the maximum critical current. When the pre-bending strain was applied, the calculated results indicate that the mechanical properties are improved due to the local work hardening, and hence the stress dependence of Ic increases.

Certification Processes for Safety-Critical and Mission-Critical Aerospace Software

NASA Technical Reports Server (NTRS)

Nelson, Stacy

2003-01-01

This document is a quick reference guide with an overview of the processes required to certify safety-critical and mission-critical flight software at selected NASA centers and the FAA. Researchers and software developers can use this guide to jumpstart their understanding of how to get new or enhanced software onboard an aircraft or spacecraft. The introduction contains aerospace industry definitions of safety and safety-critical software, as well as, the current rationale for certification of safety-critical software. The Standards for Safety-Critical Aerospace Software section lists and describes current standards including NASA standards and RTCA DO-178B. The Mission-Critical versus Safety-Critical software section explains the difference between two important classes of software: safety-critical software involving the potential for loss of life due to software failure and mission-critical software involving the potential for aborting a mission due to software failure. The DO-178B Safety-critical Certification Requirements section describes special processes and methods required to obtain a safety-critical certification for aerospace software flying on vehicles under auspices of the FAA. The final two sections give an overview of the certification process used at Dryden Flight Research Center and the approval process at the Jet Propulsion Lab (JPL).

Electric breakdown during the pulsed current spreading in the sand

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vasilyak, L. M., E-mail: vasilyak@ihed.ras.ru; Vetchinin, S. P.; Panov, V. A.

2016-03-15

Processes of spreading of the pulsed current from spherical electrodes and an electric breakdown in the quartz sand are studied experimentally. When the current density on the electrode exceeds the critical value, a nonlinear reduction occurs in the grounding resistance as a result of sparking in the soil. The critical electric field strengths for ionization and breakdown are determined. The ionization-overheating instability is shown to develop on the electrode, which leads to the current contraction and formation of plasma channels.

Critical current densities in superconducting Y-Ba-Cu-O prepared by chelating method

NASA Astrophysics Data System (ADS)

Fujisawa, Tadashi; Okuyama, Katsuro; Ohshima, Shigetoshi; Takagi, Akira

1990-10-01

The IDA, NTA, HEDTA, EDTA, TTHA, and DTPA chelating agents have been used to prepare the Y-Ba-Cu-O compounds whose critical current is presently investigated. It is noted that the precursor YBCO prepared from large stability-constant metal complexes (HEDTA, EDTA, DTPA, and TTHA) exhibited very fine and homogeneous particles. The critical current density of a 1 x 4 x 15 mm block of YBCO sintered at 880-910 C for 24 h and subsequently annealed at 500 C in an O2 flow was approximately 500 A/sq cm at 77 K, in zero magnetic field.

Huge critical current density and tailored superconducting anisotropy in SmFeAsO₀.₈F₀.₁₅ by low-density columnar-defect incorporation.

PubMed

Fang, L; Jia, Y; Mishra, V; Chaparro, C; Vlasko-Vlasov, V K; Koshelev, A E; Welp, U; Crabtree, G W; Zhu, S; Zhigadlo, N D; Katrych, S; Karpinski, J; Kwok, W K

2013-01-01

Iron-based superconductors could be useful for electricity distribution and superconducting magnet applications because of their relatively high critical current densities and upper critical fields. SmFeAsO₀.₈F₀.₁₅ is of particular interest as it has the highest transition temperature among these materials. Here we show that by introducing a low density of correlated nano-scale defects into this material by heavy-ion irradiation, we can increase its critical current density to up to 2 × 10⁷ A cm⁻² at 5 K--the highest ever reported for an iron-based superconductor--without reducing its critical temperature of 50 K. We also observe a notable reduction in the thermodynamic superconducting anisotropy, from 8 to 4 upon irradiation. We develop a model based on anisotropic electron scattering that predicts that the superconducting anisotropy can be tailored via correlated defects in semimetallic, fully gapped type II superconductors.

Critical Theory-Based Approaches in Geography Teaching Departments in Turkey

ERIC Educational Resources Information Center

Bilgili, Münür

2018-01-01

The aim of this study is to understand the relationships between critical theory-based approaches and its implementations in geography teaching departments in Turkey. Critical theory dates back to 1930s and has developed over time aiming to deal with institutions, culture and society through critical lens. Currently, critical theory-based research…

War, Critical Thinking, and Self-Understanding

ERIC Educational Resources Information Center

Noddings, Nel

2004-01-01

Can students learn to think critically if they are not asked to engage with critical issues? Fostering critical thinking is frequently stated as a fundamental aim of education, and yet many teachers report that they have been forbidden to discuss such critical issues as current wars, religion, and cultural differences in styles of parenting. The…

Neural network based automatic limit prediction and avoidance system and method

NASA Technical Reports Server (NTRS)

Calise, Anthony J. (Inventor); Prasad, Jonnalagadda V. R. (Inventor); Horn, Joseph F. (Inventor)

2001-01-01

A method for performance envelope boundary cueing for a vehicle control system comprises the steps of formulating a prediction system for a neural network and training the neural network to predict values of limited parameters as a function of current control positions and current vehicle operating conditions. The method further comprises the steps of applying the neural network to the control system of the vehicle, where the vehicle has capability for measuring current control positions and current vehicle operating conditions. The neural network generates a map of current control positions and vehicle operating conditions versus the limited parameters in a pre-determined vehicle operating condition. The method estimates critical control deflections from the current control positions required to drive the vehicle to a performance envelope boundary. Finally, the method comprises the steps of communicating the critical control deflection to the vehicle control system; and driving the vehicle control system to provide a tactile cue to an operator of the vehicle as the control positions approach the critical control deflections.

Numerical simulation of inductive method for determining spatial distribution of critical current density

NASA Astrophysics Data System (ADS)

Kamitani, A.; Takayama, T.; Tanaka, A.; Ikuno, S.

2010-11-01

The inductive method for measuring the critical current density jC in a high-temperature superconducting (HTS) thin film has been investigated numerically. In order to simulate the method, a non-axisymmetric numerical code has been developed for analyzing the time evolution of the shielding current density. In the code, the governing equation of the shielding current density is spatially discretized with the finite element method and the resulting first-order ordinary differential system is solved by using the 5th-order Runge-Kutta method with an adaptive step-size control algorithm. By using the code, the threshold current IT is evaluated for various positions of a coil. The results of computations show that, near a film edge, the accuracy of the estimating formula for jC is remarkably degraded. Moreover, even the proportional relationship between jC and IT will be lost there. Hence, the critical current density near a film edge cannot be estimated by using the inductive method.

Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

DTIC Science & Technology

2008-04-30

resumed testing, and has no plans to test. It has reduced the time needed to conduct a nuclear test. Critics raised concerns about the implications of...lieu of the current treaty.1 On October 24, Senator Jon Kyl delivered a speech critical of the CTBT and of Section 3122 in H.R. 1585, the FY2008...2007. Critics expressed concern about the implications of these policies for testing and new weapons. A statement by Physicians for Social

The mediating role of self-criticism and dependency in the association between perceptions of maternal caring and depressive symptoms.

PubMed

Campos, Rui C; Besser, Avi; Blatt, Sidney J

2010-12-01

This study examined a theoretically based mediation model including participants' perceptions of early relationships with their mother, self-criticism, dependency, and current depressive symptoms. We expect that (a) early relationships characterized by low levels of care and high levels of overprotection will be positively associated with both current depressive state and self-criticism and dependency; (b) high levels of self-criticism and dependency will be positively associated with depressive symptoms; and (c) self-criticism and dependency will play a mediating role in the association between participants' perceptions of early relationships characterized by low levels of care and high levels of overprotection and their current depressive symptoms. A nonclinical community sample of 200 Portuguese adults participated in the study. Perceptions of early relationships were measured using the mother scales of the Parental Bonding Instrument (Parker et al. [1979: Br J Med Psychol 52:1-10]), levels of self-criticism and dependency were measured using the Depressive Experiences Questionnaire (Blatt et al. [1976: J Abn Psy 6:383-389]), and depressive symptoms were measured using the Center for the Epidemiological Studies of Depression Scale (Radloff [1977: Appl Psychol Meas 1:385-401]. Structural equation modeling showed that the link between participants' perceptions of early caretaking relationships with their mothers and their current depressive symptoms is mediated by high levels of self-criticism--a personality trait associated with vulnerability to depression--but not Dependency. However, an ancillary analysis indicated that the link between participants' perceptions of early maternal overprotective relationships and their current depressive symptoms is mediated by high levels of Neediness. Findings underscore the role of perceived early relationships in psychological vulnerability to depression among highly self-critical and among highly needy individuals and highlight the negative role played by perceived mothers' early dysfunctional practices, characterized by low levels of caring and high levels of overprotection, for the self-critical vulnerability to depression and by perceived mothers' high levels of overprotection, for the neediness vulnerability to depression. These potential causal mechanisms warrant longitudinal evaluation. Theoretical and clinical implications of the findings are discussed.

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

NASA Technical Reports Server (NTRS)

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.

AEIS Policy vs. Site-Based Management: Research Agenda Implications.

ERIC Educational Resources Information Center

Nash, John B.

This paper examines the problems of centralized academic-indicator systems in light of the move toward site-based management. Problems with current practice are examined in the framework of critical inquiry. Alternatives to current accountability guidelines are presented that harmonize positivism with critical inquiry, while respecting both local…

Transformative Critique: What Confucianism Can Contribute to Contemporary Education

ERIC Educational Resources Information Center

Sigurðsson, Geir

2017-01-01

Critical thinking is currently much celebrated in the contemporary West and beyond, not least in higher education. Tertiary education students are generally expected to adopt a critical attitude in order to become responsible and constructive participants in the development of modern democratic society. Currently, the perceived desirability of…

Over 15 MA/cm2 of critical current density in 4.8 µm thick, Zr-doped (Gd,Y)Ba2Cu3Ox superconductor at 30 K, 3T.

PubMed

Majkic, Goran; Pratap, Rudra; Xu, Aixia; Galstyan, Eduard; Selvamanickam, Venkat

2018-05-03

An Advanced MOCVD (A-MOCVD) reactor was used to deposit 4.8 µm thick (Gd,Y)BaCuO tapes with 15 mol% Zr addition in a single pass. A record-high critical current density (J c ) of 15.11 MA/cm 2 has been measured over a bridge at 30 K, 3T, corresponding to an equivalent (I c ) value of 8705 A/12 mm width. This corresponds to a lift factor in critical current of ~11 which is the highest ever reported to the best of author's knowledge. The measured critical current densities at 3T (B||c) and 30, 40 and 50 K, respectively, are 15.11, 9.70 and 6.26 MA/cm 2 , corresponding to equivalent Ic values of 8705, 5586 and 3606 A/12 mm and engineering current densities (J e ) of 7068, 4535 and 2928 A/mm 2 . The engineering current density (J e ) at 40 K, 3T is 7 times higher than that of the commercial HTS tapes available with 7.5 mol% Zr addition. Such record-high performance in thick films (>1 µm) is a clear demonstration that growing thick REBCO films with high critical current density (J c ) is possible, contrary to the usual findings of strong J c degradation with film thickness. This achievement was possible due to a combination of strong temperature control and uniform laminar flow achieved in the A-MOCVD system, coupled with optimization of BaZrO 3 nanorod growth parameters.

Effect of annealing high-dose heavy-ion irradiated high-temperature superconductor wires

NASA Astrophysics Data System (ADS)

Strickland, N. M.; Wimbush, S. C.; Kluth, P.; Mota-Santiago, P.; Ridgway, M. C.; Kennedy, J. V.; Long, N. J.

2017-10-01

Heavy-ion irradiation of high-temperature superconducting thin films has long been known to generate damage tracks of amorphized material that are of close-to-ideal dimension to effectively contribute to pinning of magnetic flux lines and thereby enhance the in-field critical current. At the same time, though, the presence of these tracks reduces the superconducting volume fraction available to transport current while the irradiation process itself generates oxygen depletion and disorder in the remaining superconducting material. We have irradiated commercially available superconducting coated conductors consisting of a thick film of (Y,Dy)Ba2Cu3O7 deposited on a buffered metal tape substrate in a continuous reel-to-reel process. Irradiation was by 185 MeV 197Au ions. A high fluence of 3 × 1011 ions/cm2 was chosen to emphasize the detrimental effects. The critical current was reduced following this irradiation, but annealing at relatively low temperatures of 200 °C and 400 °C substantially restore the critical current of the irradiated material. At high fields and high temperatures there is a net benefit of critical current compared to the untreated material.

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

PubMed

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.

On Being Critical: Uniting Theory and Practice through Emancipatory Action Research

ERIC Educational Resources Information Center

Ledwith, Margaret

2007-01-01

This paper engages with some of the specific issues that challenge critical practice. My argument is related to the Carr and Kemmis debate on "staying critical" and to ideas expressed in my current book, "Community Development: A Critical Approach." I refer to critical practice as any practice that has a transformative social justice intention,…

Utilization of low temperatures in electrical machines

NASA Astrophysics Data System (ADS)

Kwasniewska-Jankowicz, L.; Mirski, Z.

1983-09-01

The dimensions of conventional and superconducting direct and alternating current generators are compared and the advantages of using superconducting magnets are examined. The critical temperature, critical current, and critical magnetic field intensity of superconductors in an induction winding are discussed as well as the mechanical properties needed for bending connectors at small radii. Investigations of cryogenic cooling, cryostats, thermal insulation and rotary seals are reported as well as results of studies of the mechanical properties of austenitic Cr-Ni steels, welded joints and plastics for insulation.

Critical Thinking and the Danger of Intellectual Conformity.

ERIC Educational Resources Information Center

Walter, Kerry S.

1987-01-01

Although the goals of critical thinking are to foster critical ability and broad-mindedness, it tends to encourage absolutism, promote passivity, and breed intolerance. The current concentration on critical thinking's reductionism should be balanced with the teaching of alternative approaches to understanding knowledge and reality. (Author/LB)

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chrzanowski, J.; Xing, W.B.; Atlan, D.

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 currentmore » 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}.« less

Low energy electron beam processing of YBCO thin films

NASA Astrophysics Data System (ADS)

Chromik, Š.; Camerlingo, C.; Sojková, M.; Štrbík, V.; Talacko, M.; Malka, I.; Bar, I.; Bareli, G.; Jung, G.

2017-02-01

Effects of low energy 30 keV electron irradiation of superconducting YBa2Cu3O7-δ thin films have been investigated by means of transport and micro-Raman spectroscopy measurements. The critical temperature and the critical current of 200 nm thick films initially increase with increasing fluency of the electron irradiation, reach the maximum at fluency 3 - 4 × 1020 electrons/cm2, and then decrease with further fluency increase. In much thinner films (75 nm), the critical temperature increases while the critical current decreases after low energy electron irradiation with fluencies below 1020 electrons/cm2. The Raman investigations suggest that critical temperature increase in irradiated films is due to healing of broken Cusbnd O chains that results in increased carrier's concentration in superconducting CuO2 planes. Changes in the critical current are controlled by changes in the density of oxygen vacancies acting as effective pinning centers for flux vortices. The effects of low energy electron irradiation of YBCO turned out to result from a subtle balance of many processes involving oxygen removal, both by thermal activation and kick-off processes, and ordering of chains environment by incident electrons.

Critical current density enhancement by phase decomposition of YBa 2Cu 4O 8 into YBa 2Cu 3O 7-σ and CuO

NASA Astrophysics Data System (ADS)

Krelaus, J.; Heinemann, K.; Ullmann, B.; Freyhardt, H. C.

1995-02-01

Bulk YBa 2Cu 4O 8 (Y-124) is prepared from YBa 2Cu 3O 7-σ (Y-123) and CuO by a powder-metallurgical method. The superconducting features of the Y-124, in particular critical current densities and activation energies, are measured resistively using a four-probe technique and magnetically using a Faraday magnetometer. In a second step the Y-124 is decomposed at high temperatures. The intragranular critical current density is measured at different annealing times, tA, in order to determine and discuss the characteristics of the jc( tA) curves.

Polaron-like vortices, dissociation transition, and self-induced pinning in magnetic superconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bulaevskii, L. N., E-mail: lnb@lanl.gov; Lin, S.-Z.

2013-09-15

Vortices in magnetic superconductors polarize spins nonuniformly and repolarize them when moving. At a low spin relaxation rate and at low bias currents, vortices carrying magnetic polarization clouds become polaron-like and their velocities are determined by the effective drag coefficient that is significantly bigger than the Bardeen-Stephen (BS) one. As the current increases, vortices release polarization clouds and the velocity as well as the voltage in the I-V characteristics jump to values corresponding to the BS drag coefficient at a critical current J{sub c}. The nonuniform components of the magnetic field and magnetization drop as the velocity increases, resulting inmore » weaker polarization and a discontinuous dynamic dissociation depinning transition. Experimentally, the jump shows up as a depinning transition and the corresponding current at the jump is the depinning current. As the current decreases, on the way back, vortices are retrapped by polarization clouds at the current J{sub r} < J{sub c}. As a result, the polaronic effect suppresses dissipation and enhances the critical current. Borocarbides (RE)Ni{sub 2}B{sub 2}C with a short penetration length and highly polarizable rare earth spins seem to be optimal systems for a detailed study of vortex polaron formation by measuring I-V characteristics. We also propose to use a superconductor-magnet multilayer structure to study polaronic mechanism of pinning with the goal to achieve high critical currents. The magnetic layers should have large magnetic susceptibility to enhance the coupling between vortices and magnetization in magnetic layers while the relaxation of the magnetization should be slow. For Nb and a proper magnet multilayer structure, we estimate the critical current density J{sub c} {approx} 10{sup 9} A/m{sup 2} at the magnetic field B Almost-Equal-To 1 T.« less

Critical current densities of Jelly-Roll and powder metallurgy Nb{sub 3}Al wires as a function of temperature and magnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thieme, C.L.H.; Kim, J.B.; Takayasu, M.

Critical current densities of multi-filamentary Nb{sub 3}Al wire made with the Jelly-Roll process (JR) and mono-core powder metallurgy process (PM) wire were measured as a function of temperature and magnetic field. The temperature dependence of the resistive critical field B{sub c2} was measured in PM wires. There is a significant difference between these resistive B{sub c2} values and the ones determined by Kramer plots. The field dependence of the critical current depends on the manufacturing method. In general, it follows a relationship that falls between pure Kramer and one where the pinning force is inversely proportional with B{sup 2}. Inmore » contrast with Nb{sub 3}Sn no maximum in the bulk pinning force is observed down to 3 T (0.15MxB{sub c2}).« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xue, Cun; He, An; Yong, Huadong

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 agreemore » 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.« less

Enhanced critical current density in the pressure-induced magnetic state of the high-temperature superconductor FeSe

PubMed Central

Jung, Soon-Gil; Kang, Ji-Hoon; Park, Eunsung; Lee, Sangyun; Lin, Jiunn-Yuan; Chareev, Dmitriy A.; Vasiliev, Alexander N.; Park, Tuson

2015-01-01

We investigate the relation of the critical current density (Jc) and the remarkably increased superconducting transition temperature (Tc) for the FeSe single crystals under pressures up to 2.43 GPa, where the Tc is increased by ~8 K/GPa. The critical current density corresponding to the free flux flow is monotonically enhanced by pressure which is due to the increase in Tc, whereas the depinning critical current density at which the vortex starts to move is more influenced by the pressure-induced magnetic state compared to the increase of Tc. Unlike other high-Tc superconductors, FeSe is not magnetic, but superconducting at ambient pressure. Above a critical pressure where magnetic state is induced and coexists with superconductivity, the depinning Jc abruptly increases even though the increase of the zero-resistivity Tc is negligible, directly indicating that the flux pinning property compared to the Tc enhancement is a more crucial factor for an achievement of a large Jc. In addition, the sharp increase in Jc in the coexisting superconducting phase of FeSe demonstrates that vortices can be effectively trapped by the competing antiferromagnetic order, even though its antagonistic nature against superconductivity is well documented. These results provide new guidance toward technological applications of high-temperature superconductors. PMID:26548444

In situ hydrostatic pressure induced improvement of critical current density and suppression of magnetic relaxation in Y(Dy0.5)Ba2Cu3O7‑δ coated conductors

NASA Astrophysics Data System (ADS)

Sang, Lina; Gutiérrez, Joffre; Cai, Chuanbing; Dou, Shixue; Wang, Xiaolin

2018-07-01

We report on the effect of in situ hydrostatic pressure on the enhancement of the in-magnetic-field critical current density parallel to the crystallographic c-axis and vortex pinning in epitaxial Y(Dy0.5)Ba2Cu3O7‑δ coated conductors prepared by metal organic deposition. Our results show that in situ hydrostatic pressure greatly enhances the critical current density at high fields and high temperatures. At 80 K and 5 T we observe a ten-fold increase in the critical current density under the pressure of 1.2 GPa, and the irreversibility line is shifted to higher fields without changing the critical temperature. The normalized magnetic relaxation rate shows that vortex creep rates are strongly suppressed due to applied pressure, and the pinning energy is significantly increased based on the collective creep theory. After releasing the pressure, we recover the original superconducting properties. Therefore, we speculate that the in situ hydrostatic pressure exerted on the coated conductor enhances the pinning of existing extended defects. This is totally different from what has been observed in REBa2Cu3O7‑δ melt-textured crystals, where the effect of pressure generates point-like defects.

Unconventional critical state in YBa2Cu3O7-δ thin films with a vortex-pin lattice fabricated by masked He+ ion beam irradiation

NASA Astrophysics Data System (ADS)

Zechner, G.; Mletschnig, K. L.; Lang, W.; Dosmailov, M.; Bodea, M. A.; Pedarnig, J. D.

2018-04-01

Thin superconducting YBa2Cu3O7-δ films are patterned with a vortex-pin lattice consisting of columnar defect regions (CDs) with 180 nm diameter and 300 nm spacing. They are fabricated by irradiation with 75 keV He+ ions through a stencil mask. Peaks of the critical current reveal the commensurate trapping of vortices in domains near the edges of the sample. Upon ramping an external magnetic field, the positions of the critical current peaks are shifted from their equilibrium values to lower magnetic fields in virgin and to higher fields in field-saturated down-sweep curves, respectively. Based on previous theoretical predictions, this irreversibility is interpreted as a nonuniform, terrace-like critical state, in which individual domains are occupied by a constant number of vortices per pinning site. The magnetoresistance, probed at low current densities, is hysteretic and angle dependent and exhibits minima that correspond to the peaks of the critical current. The minima’s positions scale with the component of the magnetic field parallel to the axes of the CDs, as long as the tilted vortices can be accommodated within the CDs. This behavior, different from unirradiated films, confirms that the CDs dominate the pinning.

High critical current superconducting tapes

DOEpatents

Holesinger, Terry G [Los Alamos, NM; Jia, Quanxi [Los Alamos, NM; Foltyn, Stephen R [Los Alamos, NM

2003-09-23

Improvements in critical current capacity for superconducting film structures are disclosed and include the use of a superconducting RE-BCO layer including a mixture of rare earth metals, e.g., yttrium and europium, where the ratio of yttrium to europium in the RE-BCO layer ranges from about 3 to 1 to from about 1.5 to 1.

Chasing Ambiguity: Critical Reflections on Working with Dance Graduates

ERIC Educational Resources Information Center

Roe, Sarah

2017-01-01

This paper questions whether are we able to foster uncertainty and ambiguity within higher education arts programmes, specifically alongside current institutional demands and embedded pedagogies. If not, then what effect does this have on current dance graduates? I attend to these questions through critical reflections upon my work as a pedagogue,…

[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].

PubMed

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).

A statistical study of current-sheet formation above solar active regions based on selforganized criticality

NASA Astrophysics Data System (ADS)

Dimitropoulou, M.; Isliker, H.; Vlahos, L.; Georgoulis, M.; Anastasiadis, A.; Toutountzi, A.

2013-09-01

We treat flaring solar active regions as physical systems having reached the self-organized critical state. Their evolving magnetic configurations in the low corona may satisfy an instability criterion, related to the excession of a specific threshold in the curl of the magnetic field. This imposed instability criterion implies an almost zero resistivity everywhere in the solar corona, except in regions where magnetic-field discontinuities and. hence, local currents, reach the critical value. In these areas, current-driven instabilities enhance the resistivity by many orders of magnitude forming structures which efficiently accelerate charged particles. Simulating the formation of such structures (thought of as current sheets) via a refined SOC cellular-automaton model provides interesting information regarding their statistical properties. It is shown that the current density in such unstable regions follows power-law scaling. Furthermore, the size distribution of the produced current sheets is best fitted by power laws, whereas their formation probability is investigated against the photospheric magnetic configuration (e.g. Polarity Inversion Lines, Plage). The average fractal dimension of the produced current sheets is deduced depending on the selected critical threshold. The above-mentioned statistical description of intermittent electric field structures can be used by collisional relativistic test particle simulations, aiming to interpret particle acceleration in flaring active regions and in strongly turbulent media in astrophysical plasmas. The above work is supported by the Hellenic National Space Weather Research Network (HNSWRN) via the THALIS Programme.

Jordanian TEFL Graduate Students' Use of Critical Thinking Skills (as Measured by the Cornell Critical Thinking Test, Level Z)

ERIC Educational Resources Information Center

Bataineh, Ruba Fahmi; Zghoul, Lamma Hmoud

2006-01-01

This study investigates the critical thinking skills of 50 students currently enrolled in the Master's TEFL Programme at Yarmouk University, Jordan. The Cornell Critical Thinking Test, Level Z is utilised to test the students' use, or lack thereof, of the critical thinking skills of deduction, semantics, credibility, induction, definition and…

Effective Instruction and Assessment Methods That Lead to Gains in Critical Thinking as Measured by the Critical Thinking Assessment Test (CAT)

ERIC Educational Resources Information Center

Leming, Katie P.

2016-01-01

Previous qualitative research on educational practices designed to improve critical thinking has relied on anecdotal or student self-reports of gains in critical thinking. Unfortunately, student self-report data have been found to be unreliable proxies for measuring critical thinking gains. Therefore, in the current interpretivist study, five…

Field-Tuned Superconductor-Insulator Transition with and without Current Bias.

PubMed

Bielejec, E; Wu, Wenhao

2002-05-20

The magnetic-field-tuned superconductor-insulator transition has been studied in ultrathin beryllium films quench condensed near 20 K. In the zero-current limit, a finite-size scaling analysis yields the scaling exponent product nuz = 1.35+/-0.10 and a critical sheet resistance, R(c), of about 1.2R(Q), with R(Q) = h/4e(2). However, in the presence of dc bias currents that are smaller than the zero-field critical currents, nuz becomes 0.75+/-0.10. This new set of exponents suggests that the field-tuned transitions with and without a dc bias current belong to different universality classes.

Josephson current in ballistic graphene Corbino disk

NASA Astrophysics Data System (ADS)

Abdollahipour, Babak; Mohammadkhani, Ramin; Khalilzadeh, Mina

2018-06-01

We solve Dirac-Bogoliubov-De-Gennes (DBdG) equation in a superconductor-normal graphene-superconductor (SGS) junction with Corbino disk structure to investigate the Josephson current through this junction. We find that the critical current Ic has a nonzero value at Dirac point in which the concentration of the carriers is zero. We show this nonzero critical current depends on the system geometry and it decreases monotonically to zero by decreasing the ratio of the inner to outer radii of the Corbino disk (R1 /R2), while in the limit of R1 /R2 → 1 it scales like a diffusive Corbino disk. The product of the critical current and the normal-state resistance IcRN increases by increasing R1 /R2 and attains the same value for the wide and short rectangular structure at the limit of R1 /R2 → 1 at zero doping. These results reveals the pseudodiffusive behavior of the graphene Corbino Josephson junction similar to the rectangular structure at the zero doping.

Consensus recommendations for the management of hyperglycaemia in critically ill patients in the Indian setting.

PubMed

Mukherjee, J J; Chatterjee, P S; Saikia, M; Muruganathan, A; Das, Ashok Kumar

2014-07-01

Hyperglycaemia occurs frequently in critically-ill patients. Not only does it occur among patients with pre-existing diabetes mellitus but elevated blood glucose values during an acute illness can also be seen in previously glucose-tolerant individuals (stress hyperglycaemia). Numerous observational studies have shown an increase in morbidity and mortality in critically ill patients with hyperglycaemia. Interestingly, outcomes in individuals with stress hyperglycaemia are worse than that in critically ill hyperglycaemic patients with pre-existing diabetes. Proper management of hyperglycaemia has been shown to result in improved clinical outcomes. Critically ill patients with hyperglycaemia should primarily be managed with intravenous insulin infusion to allow dynamic adjustment of treatment to suit the rapid changes in blood glucose values in these patients. Currently, there are in existence a fair number of published protocols to administer intensive intravenous insulin therapy that range from the relatively simple to the fairly complex. Different management strategies have been proposed depending upon whether the critically ill hyperglycaemic patient is stationed in the emergency department, the medical intensive care unit (ICU), the surgical ICU or the coronary care unit. Moreover, the ideal target blood glucose value to maintain in this group of patients remains controversial. Keeping these issues in mind, a group of leading experts in the fields of diabetes and critical care extensively reviewed the literature and framed recommendations with special attention to clinical practice in India. The aim was to formulate recommendations which are based on sound evidence and yet are simple and easy to understand and implement across the ICU throughout the country. In the current recommendations, intensive intravenous insulin therapy has been suggested as the preferred mode of managing hyperglycaemia in patients admitted to critical care settings. The current recommendations suggest using a simple and similar protocol for managing hyperglycaemia in critically-ill patients irrespective of their location among the various critical care units in a hospital. Recommendations have also been made for transition from intravenous to subcutaneous administration of insulin when the patient is transferred out of the critical care setting. It is hoped that the current recommendations shall form the basis for the management of hyperglycaemia in critically ill patients across the country.

Following Alice: Theories of Critical Thinking and Reflective Practice in Action at Postgraduate Level

ERIC Educational Resources Information Center

Swanwick, Ruth; Kitchen, Ruth; Jarvis, Joy; McCracken, Wendy; O'Neil, Rachel; Powers, Steve

2014-01-01

This paper presents a flexible framework of principles for teaching critical thinking and reflective practice skills at the postgraduate level. It reports on a collaborative project between four UK institutions providing postgraduate programmes in deaf education. Through a critical review of current theories of critical thinking and reflective…

Irradiation response of commercial, high-Tc superconducting tapes: Electromagnetic transport properties

DOE PAGES

Gapud, A. A.; Greenwood, N. T.; Alexander, J. A.; ...

2015-07-01

Effects of low dose irradiation on the electrical transport current properties of commercially available high-temperature superconducting, coated-conductor tapes were investigated, in view of potential applications in the irradiative environment of fusion reactors. Three different tapes, each with unique as-grown flux-pinning structures, were irradiated with Au and Ni ions at energies that provide a range of damage effects, with accumulated damage levels near that expected for conductors in a fusion reactor environment. Measurements using transport current determined the pre- and post-irradiation resistivity, critical current density, and pinning force density, yielding critical temperatures, irreversibility lines, and inferred vortex creep rates. Results showmore » that at the irradiation damage levels tested, any detriment to as-grown pre-irradiation properties is modest; indeed in one case already-superior pinning forces are enhanced, leading to higher critical currents.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rupich, Martin W.; Sathyamurthy, Srivatsan; Fleshler, Steven

We demonstrate a twofold increase in the in-field critical current of AMSC's standard 2G coil wire by irradiation with 18-MeV Au ions. The optimum pinning enhancement is achieved with a dose of 6 × 10 11 Au ions/cm 2. Although the 77 K, self-field critical current is reduced by about 35%, the in-field critical current (H//c) shows a significant enhancement between 4 and 50 K in fields > 1 T. The process was used for the roll-to-roll irradiation of AMSC's standard 46-mm-wide production coated conductor strips, which were further processed into standard copper laminated coil wire. The long-length wires showmore » the same enhancement as attained with short static irradiated samples. The roll-to-roll irradiation process can be incorporated in the standard 2G wire manufacturing, with no modifications to the current process. In conclusion, the enhanced performance of the wire will benefit rotating machine and magnet applications.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rupich, Martin W.; Sathyamurthy, Srivatsan; Fleshler, Steven

We demonstrate a twofold increase in the in-field critical current of AMSC's standard 2G coil wire by irradiation with 18-MeV Au ions. The optimum pinning enhancement is achieved with a dose of 6 x 10(11) Au ions/cm(2). Although the 77 K, self-field critical current is reduced by about 35%, the in-field critical current (H//c) shows a significant enhancement between 4 and 50 K in fields > 1 T. The process was used for the roll-to-roll irradiation of AMSC's standard 46-mm-wide production coated conductor strips, which were further processed into standard copper laminated coil wire. The long-length wires show the samemore » enhancement as attained with short static irradiated samples. The roll-to-roll irradiation process can be incorporated in the standard 2G wire manufacturing, with no modifications to the current process. The enhanced performance of the wire will benefit rotating machine and magnet applications.« less

Comment on ''Carrier-concentration dependence of critical superconducting current induced by the proximity effect in silicon''

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kleinsasser, A.W.

1987-06-01

It is pointed out that effect of an applied gate voltage on the critical current observed in a gate-controlled Si-coupled weak link by Nishino, Yamada, and Kawabe (Phy. Rev. B 33, 2042 (1986)) is much larger than that expected from the small change of carrier density in the link.

Apparatus for measurement of critical current in superconductive tapes

DOEpatents

Coulter, J. Yates; DePaula, Raymond

2002-01-01

A cryogenic linear positioner which is primarily used for characterizing coated conductor critical current homogeneity at 75K is disclosed. Additionally, this tool can be used to measure the positional dependence of the coated conductor resistance at room temperature, and the room temperature resistance of the underlying YBCB coating without the overlaying protective cover of silver.

Noncontact Measurement Of Critical Current In Superconductor

NASA Technical Reports Server (NTRS)

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.

A Critical Analysis of Approaches To Targeted PTSD Prevention: Current Status and Theoretically Derived Future Directions

ERIC Educational Resources Information Center

Feldner, Matthew T.; Monson, Candice M.; Friedman, Matthew J.

2007-01-01

Although efforts to prevent posttraumatic stress disorder (PTSD) have met with relatively limited success, theoretically driven preventive approaches with promising efficacy are emerging. The current article critically reviews investigations of PTSD prevention programs that target persons at risk for being exposed to a traumatic event or who have…

Critical Issues for Teacher Educators and Literacy Specialists: A View from Higher Education in New York

ERIC Educational Resources Information Center

Goatley, Virginia

2008-01-01

This article outlines five critical issues for teacher educators and literacy specialists in New York State. Intended to raise issues and share recent policy decisions, the article provides background and conversations about current policy. Readers are encouraged to make decisions about how to participate in the current conversations across the…

Dark Zones of Solid Propellant Flames: Critical Assessment and Quantitative Modeling of Experimental Datasets With Analysis of Chemical Pathways and Sensitivities

DTIC Science & Technology

2011-01-01

with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1...Research Associate at ARL with WRA, and largely completed more recently while at Dept. of Chem., SUNY, Cortland, NY. Currently unaffiliated. †Former...promised to provide an extensive, definitive review critically assessing our current understanding of DZ structure and chemistry, and providing a documented

Analysis and critical assessment of the current and near future plans of the Brazilian satellite applications program and its role in the global space program

NASA Technical Reports Server (NTRS)

Parada, N. D. J. (Principal Investigator)

1983-01-01

Brazilian programs using satellites for remote sensing, meteorology and communications are analyzed including their current status and near future plans. The experience gained and available information are used to critically discuss some aspects of great importance for the existing and prospective user countries.

Critical current oscillations of elliptical Josephson junctions with single-domain ferromagnetic layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glick, Joseph A.; Khasawneh, Mazin A.; Niedzielski, Bethany M.

We report that josephson junctions containing ferromagnetic layers are of considerable interest for the development of practical cryogenic memory and superconducting qubits. Such junctions exhibit a ground-state phase shift of π for certain ranges of ferromagnetic layer thicknesses. We present studies of Nb based micron-scale elliptically shaped Josephson junctions containing ferromagnetic barriers of Ni 81Fe 19 or Ni 65Fe 15Co 20. By applying an external magnetic field, the critical current of the junctions is found to follow characteristic Fraunhofer patterns and display sharp switching behavior suggestive of single-domain magnets. The high quality of the Fraunhofer patterns enables us to extractmore » the maximum value of the critical current even when the peak is shifted significantly outside the range of the data due to the magnetic moment of the ferromagnetic layer. The maximum value of the critical current oscillates as a function of the ferromagnetic barrier thickness, indicating transitions in the phase difference across the junction between values of zero and π. Lastly, we compare the data to previous work and to models of the 0-π transitions based on existing theories.« less

Critical current oscillations of elliptical Josephson junctions with single-domain ferromagnetic layers

DOE PAGES

Glick, Joseph A.; Khasawneh, Mazin A.; Niedzielski, Bethany M.; ...

2017-10-06

We report that josephson junctions containing ferromagnetic layers are of considerable interest for the development of practical cryogenic memory and superconducting qubits. Such junctions exhibit a ground-state phase shift of π for certain ranges of ferromagnetic layer thicknesses. We present studies of Nb based micron-scale elliptically shaped Josephson junctions containing ferromagnetic barriers of Ni 81Fe 19 or Ni 65Fe 15Co 20. By applying an external magnetic field, the critical current of the junctions is found to follow characteristic Fraunhofer patterns and display sharp switching behavior suggestive of single-domain magnets. The high quality of the Fraunhofer patterns enables us to extractmore » the maximum value of the critical current even when the peak is shifted significantly outside the range of the data due to the magnetic moment of the ferromagnetic layer. The maximum value of the critical current oscillates as a function of the ferromagnetic barrier thickness, indicating transitions in the phase difference across the junction between values of zero and π. Lastly, we compare the data to previous work and to models of the 0-π transitions based on existing theories.« less

Critical current density of TlBa 2Ca 2Cu 3O 9 thin films on MgO (100) in magnetic fields

NASA Astrophysics Data System (ADS)

Piehler, A.; Ströbel, J. P.; Reschauer, N.; Löw, R.; Schönberger, R.; Renk, K. F.; Kraus, M.; Daniel, J.; Saemann-Ischenko, G.

1994-04-01

We report on the critical current density of TlBa 2Ca 2Cu 3O 9 thin films on (100) MgO substrates in magnetic fields. Single- phase and highly c-axis oriented thin films were prepared by laser ablation in combination with thermal evaporation of Tl 2O 3. Scanning electron microscope investigations indicated a flat plate-like microstructure and DC magnetization measurements showed the onset of superconductivity at ∼ 115 K. The critical current density jc was determined from magnetization cycles. Typical values of jc were 9 × 10 5 A/cm 2 at 6 K and 2.5 × 10 5 A/cm 2 at 77 K. In a magnetic field to 1 T applied parallel to the c-axis the critical current densities were 3 × 10 5 A/cm 2 at 6 K and 3 × 10 3 A/cm 2 at 77 K. The decrease of jc at higher magnetic fields is discussed and attributed to the microstructure of the TlBa 2Ca 2Cu 3O 9 thin films.

Hawking radiation and nonequilibrium quantum critical current noise.

PubMed

Sonner, Julian; Green, A G

2012-08-31

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.

Structural and critical current properties in Al-doped MgB 2

NASA Astrophysics Data System (ADS)

Zheng, D. N.; Xiang, J. Y.; Lang, P. L.; Li, J. Q.; Che, G. C.; Zhao, Z. W.; Wen, H. H.; Tian, H. Y.; Ni, Y. M.; Zhao, Z. X.

2004-08-01

A series of Al-doped Mg 1- xAl xB 2 samples have been fabricated and systematic study on structure and superconducting properties have been carried out for the samples. In addition to a structural transition observed by XRD, TEM micrographs showed the existence of a superstructure of double c-axis lattice constant along the direction perpendicular to the boron honeycomb sheet. In order to investigate the effect of Al doping on flux pinning and critical current properties in MgB 2, measurements on the superconducting transition temperature Tc, irreversible field Birr and critical current density Jc were performed too, for the samples with the doping levels lower than 0.15 in particular. These experimental observations were discussed in terms of Al doping induced changes in carrier concentration.

Effect of notch depth of modified current collector on internal-short-circuit mitigation for lithium-ion battery

NASA Astrophysics Data System (ADS)

Wang, Meng; Noelle, Daniel J.; Shi, Yang; Le, Anh V.; Qiao, Yu

2018-01-01

Formation of internal short circuit (ISC) may result in catastrophic thermal runaway of lithium-ion battery (LIB). Among LIB cell components, direct contact between cathode and anode current collectors is most critical to the ISC behavior, yet is still relatively uninvestigated. In the current study, we analyze the effect of heterogeneity of current collector on the temperature increase of LIB cells subjected to mechanical abuse. The cathode current collector is modified by surface notches, so that it becomes effectively brittle and the ISC site can be isolated. Results from impact tests on LIB cells with modified current collectors suggest that their temperature increase can be negligible. The critical parameters include the failure strain and the failure work of modified current collector, both of which are related to the notch depth.

MgB2-based superconductors for fault current limiters

NASA Astrophysics Data System (ADS)

Sokolovsky, V.; Prikhna, T.; Meerovich, V.; Eisterer, M.; Goldacker, W.; Kozyrev, A.; Weber, H. W.; Shapovalov, A.; Sverdun, V.; Moshchil, V.

2017-02-01

A promising solution of the fault current problem in power systems is the application of fast-operating nonlinear superconducting fault current limiters (SFCLs) with the capability of rapidly increasing their impedance, and thus limiting high fault currents. We report the results of experiments with models of inductive (transformer type) SFCLs based on the ring-shaped bulk MgB2 prepared under high quasihydrostatic pressure (2 GPa) and by hot pressing technique (30 MPa). It was shown that the SFCLs meet the main requirements to fault current limiters: they possess low impedance in the nominal regime of the protected circuit and can fast increase their impedance limiting both the transient and the steady-state fault currents. The study of quenching currents of MgB2 rings (SFCL activation current) and AC losses in the rings shows that the quenching current density and critical current density determined from AC losses can be 10-20 times less than the critical current determined from the magnetization experiments.

Evidence of Spin-Injection-Induced Cooper Pair Breaking in Perovskite Ferromagnet-Insulator-Superconductor Heterostructures via Pulsed Current Measurements

NASA Technical Reports Server (NTRS)

Yeh, N. C.; Samoilov, A. V.; Veasquez, R. P.; Li, Y.

1998-01-01

The effect of spin-polarized currents on the critical current densities of cuprate superconductors is investigated in perovskite ferromagnet-insulator-superconductor heterostructures with a pulsed current technique.

High voltage and high current density vertical GaN power diodes

DOE PAGES

Fischer, A. J.; Dickerson, J. R.; Armstrong, A. M.; ...

2016-01-01

We report on the realization of a GaN high voltage vertical p-n diode operating at > 3.9 kV breakdown with a specific on-resistance < 0.9 mΩ.cm 2. Diodes achieved a forward current of 1 A for on-wafer, DC measurements, corresponding to a current density > 1.4 kA/cm 2. An effective critical electric field of 3.9 MV/cm was estimated for the devices from analysis of the forward and reverse current-voltage characteristics. Furthermore this suggests that the fundamental limit to the GaN critical electric field is significantly greater than previously believed.

Global trends in critical values practices and their harmonization.

PubMed

Kost, Gerald J; Hale, Kristin N

2011-02-01

The objectives of this article were 1) to identify current trends in critical values practices in North America, Europe, and other regions; 2) to describe progress toward harmonization of critical limits; and 3) to synthesize strategies that will encourage global consensus. Critical limits are described in national surveys. Critical value practices are guided by federal statutes, The Joint Commission regulations, and accreditation requirements in the US; by provincial healthcare agencies in Canada; by thought leaders and ISO EN 15189:2007 in Europe; and in SE Asia, mostly by ad hoc policies lacking statutory grip. Review of databases, literature, websites, federal statutes, litigation, official policies, current affairs, and accreditation agency requirements. Practical strategies will accelerate harmonization of critical values practices, as follows: a) continue national and international survey comparisons; b) clarify age, ethnic, and subject dependencies; c) standardize qualitative and quantitative decision levels for urgent clinician notification; d) monitor compliance and timeliness for safety; and e) alert high frequencies of critical values related to adverse events. New expectations and communication technologies present opportunities for enhanced performance using wireless closed-loop reporting with recipient acknowledgment to reduce phone calls and improve efficiency. Hospitals worldwide can benefit from developing consensus for critical values practices.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geerkens, A.; Frenck, H.J.; Ewert, S.

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.

Analysis of critical thinking ability in direct current electrical problems solving

NASA Astrophysics Data System (ADS)

Hartono; Sunarno, Widha; Sarwanto; Arya Nugraha, Dewanta

2017-11-01

This study concern on analyzing the ability of students in critical thinking skills on the subject matter of direct current electricity. Samples were taken using purposive random sampling consisted of 32 students of grade XI, Multimedia 1, SMK Negeri 3 Surakarta in academic year 2016/2017. This study used descriptive quantitative method. The data were collected using tests and interviews regarding the subject matter of direct current electricity. Based on the results, students are getting some difficulties in solving problem in indicator 4. The average of students’ correct answer is 62.8%.

Angular dependence of critical current density and magnetoresistance of sputtered high-T(sub c)-films

NASA Technical Reports Server (NTRS)

Geerkens, A.; Meven, M.; Frenck, H.-J.; Ewert, S.

1995-01-01

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.

Effectiveness of past and current critical incident analysis on reflective learning and practice change.

PubMed

Vachon, Brigitte; LeBlanc, Jeannette

2011-09-01

Critical incident analysis (CIA) is one of the strategies frequently used to facilitate reflective learning. It involves the thorough description and analysis of an authentic and experienced event within its specific context. However, CIA has also been described as having the potential to expose vulnerabilities, threaten learners' coping mechanisms and increase rather than reduce their anxiety levels. The aim of this study was to compare the analysis of current critical incidents with that of past critical incidents, and to further explore why and how the former is more conducive to reflective learning and practice change than the latter. A collaborative research study was conducted. Eight occupational therapists were recruited to participate in a reflective learning group that convened for 12 meetings held over a 15-month period. The group facilitator planned and adapted the learning strategies to be used to promote reflective learning and guided the group process. Critical incident analysis represented the main activity carried out in the group discussions. The data collected were analysed using the grounded theory method. Three phenomena were found to differentiate between the learning contexts created by the analysis of, respectively, past and current critical incidents: attitudinal disposition; legitimacy of purpose, and the availability of opportunities for experimentation. Analysis of current clinical events was found to improve participants' motivation to self-evaluate, to increase their self-efficacy, and to help them transfer learning into action and to progressively self-regulate. The results of this collaborative research study suggest that the analysis of current clinical events in order to promote reflection offers a safer and more constructive learning environment than does the analysis of incidents that have occurred in the past. This learning strategy is directly grounded in health professional practice. The remaining challenge for continuing education providers is that of creating conditions conducive to its use. © Blackwell Publishing Ltd 2011.

Concurrent Data Elicitation Procedures, Processes, and the Early Stages of L2 Learning: A Critical Overview

ERIC Educational Resources Information Center

Leow, Ronald P.; Grey, Sarah; Marijuan, Silvia; Moorman, Colleen

2014-01-01

Given the current methodological interest in eliciting direct data on the cognitive processes L2 learners employ as they interact with L2 data during the early stages of the learning process, this article takes a critical and comparative look at three concurrent data elicitation procedures currently employed in the SLA literature: Think aloud (TA)…

No Good Wars: Teaching the History of Modern American Wars as a Means of Resisting Current Ones

ERIC Educational Resources Information Center

Long, Kenneth

2008-01-01

In the fall 2005 semester, the author designed a course in the history of America's modern wars hoping to encourage students to criticize and oppose the country's current aggressions in Afghanistan and Iraq. Surveys of student attitude change suggest that the course did promote criticism but did far less to facilitate student activism. The author…

Critical Infrastructures: Background, Policy, and Implementation

DTIC Science & Technology

2006-04-18

initially approved. The current review process for such purchases, implemented under authority of the Exon- Florio provision of the Defense Production Act (50...legislative proposals “broaden” coverage of Exon- Florio to include the purchase of assets associated with critical infrastructure. As currently written...Exon- Florio covers persons engaged in interstate commerce. While this covers a broad range of “persons,” extending beyond those that might be part

Teaching the Banking System According to Critical Education. A Study of a Schoolbook on Economics

ERIC Educational Resources Information Center

Vaina, Maria; Katidioti, Evaggelia; Ktitikos, Antonis

2013-01-01

The main objective of the current paper is to establish the deficiencies of teaching Economics in the Greek educational system. It also proposes critical education as a way of partially overcoming these issues and the way it can contribute to the protection of the everyday man and woman against the rising and current existential threats of the…

Implementing a Grant Proposal Writing Exercise in Undergraduate Science Courses to Incorporate Real-World Applications and Critical Analysis of Current Literature

ERIC Educational Resources Information Center

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…

Critical Care Nurses' Reasons for Poor Attendance at a Continuous Professional Development Program.

PubMed

Viljoen, Myra; Coetzee, Isabel; Heyns, Tanya

2016-12-01

Society demands competent and safe health care, which obligates professionals to deliver quality patient care using current knowledge and skills. Participation in continuous professional development programs is a way to ensure quality nursing care. Despite the importance of continuous professional development, however, critical care nurse practitioners' attendance rates at these programs is low. To explore critical care nurses' reasons for their unsatisfactory attendance at a continuous professional development program. A nominal group technique was used as a consensus method to involve the critical care nurses and provide them the opportunity to reflect on their experiences and challenges related to the current continuous professional development program for the critical care units. Participants were 14 critical care nurses from 3 critical care units in 1 private hospital. The consensus was that the central theme relating to the unsatisfactory attendance at the continuous professional development program was attitude. In order of importance, the 4 contributing priorities influencing attitude were communication, continuous professional development, time constraints, and financial implications. Attitude relating to attending a continuous professional development program can be changed if critical care nurses are aware of the program's importance and are involved in the planning and implementation of a program that focuses on the nurses' individual learning needs. ©2016 American Association of Critical-Care Nurses.

Critical infrastructure protection.

PubMed

Deitz, Kim M

2012-01-01

Current government policies for protecting the nation's critical infrastructure are described in this article which focuses on hospital disaster planning and incident management and the significant role of Security in infrastructure protection

Charge imbalance and Josephson effects in superconductor-normal metal mesoscopic structures

NASA Astrophysics Data System (ADS)

Volkov, A. F.

2007-11-01

We consider a SBS Josephson junction the superconducting electrodes S of which are in contact with normal metal reservoirs ( B means a barrier). For temperatures near Tc we calculate an effective critical current Ic* and the resistance of the system at the currents I

Engineered pinning landscapes for enhanced 2G coil wire

DOE PAGES

Rupich, Martin W.; Sathyamurthy, Srivatsan; Fleshler, Steven; ...

2016-04-01

We demonstrate a twofold increase in the in-field critical current of AMSC's standard 2G coil wire by irradiation with 18-MeV Au ions. The optimum pinning enhancement is achieved with a dose of 6 × 10 11 Au ions/cm 2. Although the 77 K, self-field critical current is reduced by about 35%, the in-field critical current (H//c) shows a significant enhancement between 4 and 50 K in fields > 1 T. The process was used for the roll-to-roll irradiation of AMSC's standard 46-mm-wide production coated conductor strips, which were further processed into standard copper laminated coil wire. The long-length wires showmore » the same enhancement as attained with short static irradiated samples. The roll-to-roll irradiation process can be incorporated in the standard 2G wire manufacturing, with no modifications to the current process. In conclusion, the enhanced performance of the wire will benefit rotating machine and magnet applications.« less

Inelastic effects of Josephson junctions

NASA Astrophysics Data System (ADS)

Ranjan, Samir

We have investigated the effects of the inelastic interaction of electrons with phonons in the barrier region of S-I-S and S-N-S Josephson junctions. We find that under suitable conditions this mechanism can cause substantial modifications of the temperature dependence of the critical current jsb{c} as the inevitable loss of coherence can be more than compensated by the enhancement of the tunneling probability resulting from the phonon absorption. The effect depends strongly on the ratio qsb{TF}a of the junction width a to the screening length in the barrier region. For a S-I-S junction, a monotonic decrease in the critical current with temperature is found for qsb{TF}a ≫ 1 whereas for qsb{TF}a ≪ 1, the appearance of a peak in jsb{c}(T) near Tsb{c} is predicted. This new interesting effect is the consequence of the competition between the decrease of the superconducting gap function and the increase in the number of phonons with temperature. A wide range of parameter values has been explored and contact with relevant experimental results has been made. For an S-N-S junction, there is a large increase in the coherence length in the non-superconducting region leading to a substantial enhancement of the critical current over a wide range of temperature. It turns out that the entire temperature range can be divided broadly into two regimes. At low temperatures, the electron predominantly exchanges energy with just one phonon and it is this process that mainly determines the critical current. At higher temperatures the critical current is determined by processes in which the electrons exchange energy with many phonons during their under barrier motion.

Progress in second-generation HTS wire development and manufacturing

NASA Astrophysics Data System (ADS)

Selvamanickam, V.; Chen, Y.; Xiong, X.; Xie, Y.; Zhang, X.; Rar, A.; Martchevskii, M.; Schmidt, R.; Lenseth, K.; Herrin, J.

2008-09-01

2007 has marked yet another year of continued rapid progress in developing and manufacturing high-performance, long-length second-generation (2G) HTS wires at high speeds. Using ion beam assisted deposition (IBAD) MgO and associated buffer sputtering processes, SuperPower has now exceeded piece lengths of 1000 m of fully buffered tape reproducibly with excellent in-plane texture of 6-7 degrees and uniformity of about 2%. These kilometer lengths are produced at high speeds of about 350 m/h of 4 mm wide tape. In combination with metal organic chemical vapor deposition (MOCVD), 2G wires up to single piece lengths to 790 m with a minimum critical current value of 190 A/cm corresponding to a Critical current × Length performance of 150,100 Am have been achieved. Tape speeds up to 180 m/h have been reached MOCVD while maintaining critical currents above 200 A/cm in 100+ m lengths. Thick film MOCVD technology has been transitioned to Pilot manufacturing system where a minimum critical current of 320 A/cm has been demonstrated over a length of 155 m processed at a speed of 70 m/h in 4 mm width. Finally, nearly 10,000 m of 2G wire has been produced, exhaustively tested, and delivered to the Albany Cable project. The average minimum critical current of the wire delivered in 225 segments of 43-44 m is 70 A in 4 mm widths. A 30 m cable has been fabricated with this wire by Sumitomo Electric and has been installed in the power grid of National Grid in downtown Albany and is the world’s first 2G device installed in the grid.

Program Development for Primary School Teachers' Critical Thinking

ERIC Educational Resources Information Center

Boonjeam, Waraporn; Tesaputa, Kowat; Sri-ampai, Anan

2017-01-01

The objectives of this research were: 1) to study the elements and indicators of primary school teachers' critical thinking, 2) to study current situation, desirable situation, development technique, and need for developing the primary school teachers' critical thinking, 3) to develop the program for developing the primary school teachers'…

Critical Thinking Assessment across Four Sustainability-Related Experiential Learning Settings

ERIC Educational Resources Information Center

Heinrich, William F.; Habron, Geoffrey B.; Johnson, Heather L.; Goralnik, Lissy

2015-01-01

Today's complex societal problems require both critical thinking and an engaged citizenry. Current practices in higher education, such as service learning, suggest that experiential learning can serve as a vehicle to encourage students to become engaged citizens. However, critical thinking is not necessarily a part of every experiential learning…

Critical Discourse Analysis, Adult Education and "Fitba"

ERIC Educational Resources Information Center

Player, John

2013-01-01

In this article I will use an example of current adult education practice, the Glory and Dismay Football Literacies Programme (GDFLP) to appraise the value of critical discourse analysis (CDA) for adult learners, both individually and collectively, and for adult education practitioners with an interest in developing critical literacy skills. The…

Rethinking Critical Thinking

ERIC Educational Resources Information Center

Downs, Christopher J.

2008-01-01

Critical thinking is of primary importance in higher education, yet the concept remains slippery and the skill elusive. The author argues that most current critical thinking textbooks are out of line with the seminal work of John Dewey. Rather than logical argument and justification, it is suggested that carefulness, open-mindedness and creativity…

Empowering the Foreign Language Learner through Critical Literacies Development

ERIC Educational Resources Information Center

Keneman, Margaret

2016-01-01

This article examines current pedagogical trends in the foreign language classroom and argues that a critical literacies pedagogical approach (Freire, 1970) should guide instruction. A critical literacies pedagogical approach is then discussed in the context of foreign language teaching and learning, and particular attention in this article is…

Environmental Activities for Teaching Critical Thinking. [Environmental Education Information Report.

ERIC Educational Resources Information Center

Howe, Robert W.; Disinger, John F.

The ability to think critically is essential if individuals are to live, work, and function effectively in our current and changing society. The activities included in this publication were selected to identify a variety of effective strategies for teaching critical thinking skills through environmental education. Activities include library…

Transforming Violent Selves through Reflection in Critical Communicative Research

ERIC Educational Resources Information Center

Flecha, Ainhoa; Pulido, Cristina; Christou, Miranda

2011-01-01

Currently, teenagers are being socialized into a world of violent realities, not only through social interaction but also through interaction via the media, especially via the Internet. Research conducted using the critical communicative methodology has shown that this methodology helps young people to reflect critically about their violent…

A Critical Analysis of the Conceptualisation of "Coaching Philosophy"

ERIC Educational Resources Information Center

Cushion, Christopher; Partington, Mark

2016-01-01

The aim of this paper was to critically review existing literature relating to, and critically analyse current conceptualisations of, "coaching philosophy." The review reveals a bewildering approach to definitions, terms and frameworks that have limited explanation and reveal a lack of conceptual clarity. It is argued that rather than…

The Effect of Information Literacy on Teachers' Critical Thinking Disposition

ERIC Educational Resources Information Center

Saglam, Aycan Çiçek; Çankaya, Ibrahim; Üçer, Hakan; Çetin, Muhammet

2017-01-01

The concepts of information literacy and critical thinking are two important concepts of today's information and technology age closely related to each other and sometimes used interchangeably. The purpose of the current study is to explore the relationship between the secondary school teachers' critical thinking disposition and information…

Climate change impacts on forest soil critical acid loads and exceedances at a national scale

Treesearch

Steven G. McNulty; Erika C. Cohen; Jennifer A. Moore Myers

2013-01-01

Federal agencies are currently developing guidelines for forest soil critical acid loads across the United States. A critical acid load is defined as the amount of acid deposition (usually expressed on an annual basis) that an ecosystem can absorb. Traditionally, an ecosystem is considered to be at risk for health impairment when the critical acid load exceeds a level...

A Critical Co-Constructed Autoethnography of a Gendered Cross-Cultural Mentoring between Two Early Career Latin@ Scholars Working in the Deep South

ERIC Educational Resources Information Center

Suriel, Regina L.; Martinez, James; Evans-Winters, Venus

2018-01-01

Multicultural mentoring has been suggested to support Latin@ faculty success in their careers, yet current literature on effective mentorships of Latin@ faculty is limited. This critical co-constructed autoethnography draws on critical race theory (CRT) and latin@ critical race theory (LatCrit) frameworks to highlight the lived experiences and key…

Architecture for high critical current superconducting tapes

DOEpatents

Jia, Quanxi; Foltyn, Stephen R.

2002-01-01

Improvements in critical current capacity for superconducting film structures are disclosed and include the use of, e.g., multilayer YBCO structures where individual YBCO layers are separated by a layer of an insulating material such as CeO.sub.2 and the like, a layer of a conducting material such as strontium ruthenium oxide and the like or by a second superconducting material such as SmBCO and the like.

Analysis of electric current flow through the HTc multilayered superconductors

NASA Astrophysics Data System (ADS)

Sosnowski, J.

2016-02-01

Issue of the flow of the transport current through multilayered high-temperature superconductors is considered, depending on the direction of the electric current towards the surface of the superconducting CuO2 layers. For configuration of the current flow inside of the layers and for perpendicular magnetic field, it will be considered the current limitations connected with interaction of pancake type vortices with nano-sized defects, created among other during fast neutrons irradiation. So it makes this issue associated with work of nuclear energy devices, like tokamak ITER, LHC and actually developed accelerator Nuclotron-NICA, as well as cryocables. Phenomenological analysis of the pinning potential barrier formation will be in the paper given, which determines critical current flow inside the plane. Comparison of theoretical model with experimental data will be presented too as well as influence of fast neutrons irradiation dose on critical current calculated. For current direction perpendicular to superconducting planes the current-voltage characteristics are calculated basing on model assuming formation of long intrinsic Josephson's junctions in layered HTc superconductors.

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

PubMed Central

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

Isotropic enhancement in the critical current density of YBCO thin films incorporating nanoscale Y2BaCuO5 inclusions

NASA Astrophysics Data System (ADS)

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

2017-09-01

The effect of incorporation of nanoscale Y2BaCuO5 (Y211) inclusions on the vortex pinning properties of YBa2Cu3O7-δ (YBCO or Y123) superconducting thin films is investigated in detail on the basis of variation of critical current density (JC) with applied magnetic field and also with the orientation of the applied magnetic field at two different temperatures: 77 K and 65 K. Surface modified target approach is employed to incorporate nanoscale Y211 inclusions into the superconducting YBCO matrix. The efficiency of Y211 nanoinclusions in reducing the angular anisotropy of critical current density is found to be significant. The observed angular dependence of the critical current density is discussed on the basis of mutually occupied volume by a vortex and spherical and/or planar defect. A dip in JC near the ab-plane is also observed which has been analyzed on the basis of variation of pinning potential corresponding to a spherical (3-D) or planar (2-D) pinning center and has been attributed to a reduced interaction volume of the vortices with a pinning center and competing nature of the potentials due to spherical and planar defects.

Spatial buckling analysis of current-carrying nanowires in the presence of a longitudinal magnetic field accounting for both surface and nonlocal effects

NASA Astrophysics Data System (ADS)

Foroutan, Shahin; Haghshenas, Amin; Hashemian, Mohammad; Eftekhari, S. Ali; Toghraie, Davood

2018-03-01

In this paper, three-dimensional buckling behavior of nanowires was investigated based on Eringen's Nonlocal Elasticity Theory. The electric current-carrying nanowires were affected by a longitudinal magnetic field based upon the Lorentz force. The nanowires (NWs) were modeled based on Timoshenko beam theory and the Gurtin-Murdoch's surface elasticity theory. Generalized Differential Quadrature (GDQ) method was used to solve the governing equations of the NWs. Two sets of boundary conditions namely simple-simple and clamped-clamped were applied and the obtained results were discussed. Results demonstrated the effect of electric current, magnetic field, small-scale parameter, slenderness ratio, and nanowires diameter on the critical compressive buckling load of nanowires. As a key result, increasing the small-scale parameter decreased the critical load. By the same token, increasing the electric current, magnetic field, and slenderness ratio resulted in a decrease in the critical load. As the slenderness ratio increased, the effect of nonlocal theory decreased. In contrast, by expanding the NWs diameter, the nonlocal effect increased. Moreover, in the present article, the critical values of the magnetic field of strength and slenderness ratio were revealed, and the roles of the magnetic field, slenderness ratio, and NWs diameter on higher buckling loads were discussed.

Josephson junction Q-spoiler

DOEpatents

Clarke, J.; Hilbert, C.; Hahn, E.L.; Sleator, T.

1986-03-25

An automatic Q-spoiler comprising at least one Josephson tunnel junction connected in an LC circuit for flow of resonant current therethrough. When in use in a system for detecting the magnetic resonance of a gyromagnetic particle system, a high energy pulse of high frequency energy irradiating the particle system will cause the critical current through the Josephson tunnel junctions to be exceeded, causing the tunnel junctions to act as resistors and thereby damp the ringing of the high-Q detection circuit after the pulse. When the current has damped to below the critical current, the Josephson tunnel junctions revert to their zero-resistance state, restoring the Q of the detection circuit and enabling the low energy magnetic resonance signals to be detected.

Josephson junction Q-spoiler

DOEpatents

Clarke, John; Hilbert, Claude; Hahn, Erwin L.; Sleator, Tycho

1988-01-01

An automatic Q-spoiler comprising at least one Josephson tunnel junction connected in an LC circuit for flow of resonant current therethrough. When in use in a system for detecting the magnetic resonance of a gyromagnetic particle system, a high energy pulse of high frequency energy irradiating the particle system will cause the critical current through the Josephson tunnel junctions to be exceeded, causing the tunnel junctions to act as resistors and thereby damp the ringing of the high-Q detection circuit after the pulse. When the current has damped to below the critical current, the Josephson tunnel junctions revert to their zero-resistance state, restoring the Q of the detection circuit and enabling the low energy magnetic resonance signals to be detected.

Superconducting properties of nano-sized SiO2 added YBCO thick film on Ag substrate

NASA Astrophysics Data System (ADS)

Almessiere, Munirah Abdullah; Al-Otaibi, Amal lafy; Azzouz, Faten Ben

2017-10-01

The microstructure and the flux pinning capability of SiO2-added YBa2Cu3Oy thick films on Ag substrates were investigated. A series of YBa2Cu3Oy thick films with small amounts (0-0.5 wt%) of nano-sized SiO2 particles (12 nm) was prepared. The thicknesses of the prepared thick films was approximately 100 µm. Phase analysis by x-ray diffraction and microstructure examination by scanning electron microscopy were performed and the critical current density dependence on the applied magnetic field Jc(H) and electrical resistivity ρ(T) were investigated. The magnetic field and temperature dependence of the critical current density (Jc) was calculated from magnetization measurements using Bean's critical state model. The results showed that the addition of a small amount (≤0.02 wt%) of SiO2 was effective in enhancing the critical current densities in the applied magnetic field. The sample with 0.01 wt% of added SiO2 exhibited a superconducting characteristics under an applied magnetic field for a temperature ranging from 10 to 77 K.

Electromigration kinetics and critical current of Pb-free interconnects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Minhua; Rosenberg, Robert

2014-04-07

Electromigration kinetics of Pb-free solder bump interconnects have been studied using a single bump parameter sweep technique. By removing bump to bump variations in structure, texture, and composition, the single bump sweep technique has provided both activation energy and power exponents that reflect atomic migration and interface reactions with fewer samples, shorter stress time, and better statistics than standard failure testing procedures. Contact metallurgies based on Cu and Ni have been studied. Critical current, which corresponds to the Blech limit, was found to exist in the Ni metallurgy, but not in the Cu metallurgy. A temperature dependence of critical currentmore » was also observed.« less

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

NASA Technical Reports Server (NTRS)

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.

The evolution of pediatric critical care nursing: past, present, and future.

PubMed

Foglia, Dorothy C; Milonovich, Lisa M

2011-06-01

Although current nursing literature is overflowing with information related to the history of nursing in general, and even pediatric nursing, very little is published about PICU nursing. The evolution of pediatric critical care nursing is presented based on a historical context, the current state, and future projections. More specifically, this treatise focuses on the environment, the patient and family, and of course, the PICU nurse. Concluding remarks provide an insight into how health care reforms and how the use of clinical information technology will affect the role of the pediatric critical care nurse in the future. Copyright © 2011 Elsevier Inc. All rights reserved.

Probes for investigating the effect of magnetic field, field orientation, temperature and strain on the critical current density of anisotropic high-temperature superconducting tapes in a split-pair 15 T horizontal magnet.

PubMed

Sunwong, P; Higgins, J S; Hampshire, D P

2014-06-01

We present the designs of probes for making critical current density (Jc) measurements on anisotropic high-temperature superconducting tapes as a function of field, field orientation, temperature and strain in our 40 mm bore, split-pair 15 T horizontal magnet. Emphasis is placed on the design of three components: the vapour-cooled current leads, the variable temperature enclosure, and the springboard-shaped bending beam sample holder. The vapour-cooled brass critical-current leads used superconducting tapes and in operation ran hot with a duty cycle (D) of ~0.2. This work provides formulae for optimising cryogenic consumption and calculating cryogenic boil-off, associated with current leads used to make J(c) measurements, made by uniformly ramping the current up to a maximum current (I(max)) and then reducing the current very quickly to zero. They include consideration of the effects of duty cycle, static helium boil-off from the magnet and Dewar (b'), and the maximum safe temperature for the critical-current leads (T(max)). Our optimized critical-current leads have a boil-off that is about 30% less than leads optimized for magnet operation at the same maximum current. Numerical calculations show that the optimum cross-sectional area (A) for each current lead can be parameterized by LI(max)/A = [1.46D(-0.18)L(0.4)(T(max) - 300)(0.25D(-0.09)) + 750(b'/I(max))D(10(-3)I(max)-2.87b') × 10⁶ A m⁻¹ where L is the current lead's length and the current lead is operated in liquid helium. An optimum A of 132 mm(2) is obtained when I(max) = 1000 A, T(max) = 400 K, D = 0.2, b' = 0.3 l h(-1) and L = 1.0 m. The optimized helium consumption was found to be 0.7 l h(-1). When the static boil-off is small, optimized leads have a boil-off that can be roughly parameterized by: b/I(max)  ≈ (1.35 × 10(-3))D(0.41) l h(‑1) A(-1). A split-current-lead design is employed to minimize the rotation of the probes during the high current measurements in our high-field horizontal magnet. The variable-temperature system is based on the use of an inverted insulating cup that operates above 4.2 K in liquid helium and above 77.4 K in liquid nitrogen, with a stability of ±80 mK to ±150 mK. Uniaxial strains of -1.4% to 1.0% can be applied to the sample, with a total uncertainty of better than ±0.02%, using a modified bending beam apparatus which includes a copper beryllium springboard-shaped sample holder.

Critical carbon input to maintain current soil organic carbon stocks in global wheat systems

PubMed Central

Wang, Guocheng; Luo, Zhongkui; Han, Pengfei; Chen, Huansheng; Xu, Jingjing

2016-01-01

Soil organic carbon (SOC) dynamics in croplands is a crucial component of global carbon (C) cycle. Depending on local environmental conditions and management practices, typical C input is generally required to reduce or reverse C loss in agricultural soils. No studies have quantified the critical C input for maintaining SOC at global scale with high resolution. Such information will provide a baseline map for assessing soil C dynamics under potential changes in management practices and climate, and thus enable development of management strategies to reduce C footprint from farm to regional scales. We used the soil C model RothC to simulate the critical C input rates needed to maintain existing soil C level at 0.1° × 0.1° resolution in global wheat systems. On average, the critical C input was estimated to be 2.0 Mg C ha−1 yr−1, with large spatial variability depending on local soil and climatic conditions. Higher C inputs are required in wheat system of central United States and western Europe, mainly due to the higher current soil C stocks present in these regions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content. PMID:26759192

Automated Eddy Current Inspection on Space Shuttle Hardware

NASA Technical Reports Server (NTRS)

Hartmann, John; Felker, Jeremy

2007-01-01

Over the life time of the Space Shuttle program, metal parts used for the Reusable Solid Rocket Motors (RSRMs) have been nondestructively inspected for cracks and surface breaking discontinuities using magnetic particle (steel) and penetrant methods. Although these inspections adequately screened for critical sized cracks in most regions of the hardware, it became apparent after detection of several sub-critical flaws that the processes were very dependent on operator attentiveness and training. Throughout the 1990's, eddy current inspections were added to areas that had either limited visual access or were more fracture critical. In the late 1990's. a project was initiated to upgrade NDE inspections with the overall objective of improving inspection reliability and control. An automated eddy current inspection system was installed in 2001. A figure shows one of the inspection bays with the robotic axis of the system highlighted. The system was programmed to inspect the various case, nozzle, and igniter metal components that make up an RSRM. both steel and aluminum. For the past few years, the automated inspection system has been a part of the baseline inspection process for steel components. Although the majority of the RSRM metal part inventory ts free of detectable surface flaws, a few small, sub-critical manufacturing defects have been detected with the automated system. This paper will summarize the benefits that have been realized with the current automated eddy current system, as well as the flaws that have been detected.

Effect of Common Cryoprotectants on Critical Warming Rates and Ice Formation in Aqueous Solutions

PubMed Central

Hopkins, Jesse B.; Badeau, Ryan; Warkentin, Matthew; Thorne, Robert E.

2012-01-01

Ice formation on warming is of comparable or greater importance to ice formation on cooling in determining survival of cryopreserved samples. Critical warming rates required for ice-free warming of vitrified aqueous solutions of glycerol, dimethyl sulfoxide, ethylene glycol, polyethylene glycol 200 and sucrose have been measured for warming rates of order 10 to 104 K/s. Critical warming rates are typically one to three orders of magnitude larger than critical cooling rates. Warming rates vary strongly with cooling rates, perhaps due to the presence of small ice fractions in nominally vitrified samples. Critical warming and cooling rate data spanning orders of magnitude in rates provide rigorous tests of ice nucleation and growth models and their assumed input parameters. Current models with current best estimates for input parameters provide a reasonable account of critical warming rates for glycerol solutions at high concentrations/low rates, but overestimate both critical warming and cooling rates by orders of magnitude at lower concentrations and larger rates. In vitrification protocols, minimizing concentrations of potentially damaging cryoprotectants while minimizing ice formation will require ultrafast warming rates, as well as fast cooling rates to minimize the required warming rates. PMID:22728046

Role of oral pre-exposure prophylaxis (PrEP) in current and future HIV prevention strategies.

PubMed

Burns, David N; Grossman, Cynthia; Turpin, Jim; Elharrar, Vanessa; Veronese, Fulvia

2014-12-01

Treatment as prevention is expected to have a major role in reducing HIV incidence, but other prevention interventions will also be required to bring the epidemic under control, particularly among key populations. One or more forms of pre-exposure prophylaxis (PrEP) will likely play a critical role. Oral PrEP with emtricitabine-tenofovir (Truvada®) is currently available in the US and some other countries, but uptake has been slow. We review the concerns that have contributed to this slow uptake and discuss current and future research in this critical area of HIV prevention research.

A Critical Assessment of Research on Neurotransmitters in Alzheimer's Disease.

PubMed

Reddy, P Hemachandra

2017-01-01

The purpose of this mini-forum, "Neurotransmitters and Alzheimer's Disease", is to critically assess the current status of neurotransmitters in Alzheimer's disease. Neurotransmitters are essential neurochemicals that maintain synaptic and cognitive functions in mammals, including humans, by sending signals across pre- to post-synaptic neurons. Authorities in the fields of synapses and neurotransmitters of Alzheimer's disease summarize the current status of basic biology of synapses and neurotransmitters, and also update the current status of clinical trials of neurotransmitters in Alzheimer's disease. This article discusses the prevalence, economic impact, and stages of Alzheimer's dementia in humans.

Expressed Emotion-Criticism and Risk of Depression Onset in Children

ERIC Educational Resources Information Center

Burkhouse, Katie L.; Uhrlass, Dorothy J.; Stone, Lindsey B.; Knopik, Valerie S.; Gibb, Brandon E.

2012-01-01

The primary goal of the current study was to examine the impact of maternal criticism (expressed emotion-criticism; EE-Crit) on the prospective development of depressive episodes in children. In addition to examining baseline levels of EE-Crit, we also sought to determine whether distinct subgroups (latent classes) of mothers could be identified…

Critical Consciousness: Current Status and Future Directions

ERIC Educational Resources Information Center

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…

The Relationship between Critical Thinking and EFL Learners' Speaking Ability

ERIC Educational Resources Information Center

Ramezani, Raana; Larsari, Ebrahim Ezzati; Kiasi, Mohammad Aghajanzadeh

2016-01-01

The current study sought to investigate the relationship between critical thinking and speaking ability among EFL students at Payame Noor University (PNU) of Rasht. This research concerned determining the fact that whether language students who are as critical thinker, perform better in their speaking ability or not. In order to answer the…

Using Computers and Original Texts to Teach Critical Reading and Thinking.

ERIC Educational Resources Information Center

Orndorff, Joseph

While ability to read and think critically is the very basis of post-secondary education, increasing numbers of college students lack these skills. A sequence of two courses in critical reading and thinking are currently offered in the Concentrated Studies program at Duquesne University in Pennsylvania. In these courses, students who are…

A Synthesis and Survey of Critical Success Factors for Computer Technology Projects

ERIC Educational Resources Information Center

Baker, Ross A.

2012-01-01

The author investigated the existence of critical success factors for computer technology projects. Current research literature and a survey of experienced project managers indicate that there are 23 critical success factors (CSFs) that correlate with project success. The survey gathered an assessment of project success and the degree to which…

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

ERIC Educational Resources Information Center

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…

The Case against "Critical Thinking Skills": In Pursuit of a Humanizing Pedagogy

ERIC Educational Resources Information Center

Anderson, Morgan

2015-01-01

Current educational discourse is rife with the phrase "critical thinking skills." The term is wielded with such indiscretion among educators, reformers, and education policy makers that is has become commonsensical to believe that imparting critical thinking skills is an indispensable aspect of education. For example, according to the…

Towards a Critical Theory of Educational Technology

ERIC Educational Resources Information Center

Okan, Zuhal

2007-01-01

The purpose of this study is to offer a critical consideration of current initiatives, and common sense discourses, forcing educators to adopt and integrate educational technology on a large scale. This study argues that it is time, in the relative absence of a critical debate, to ask questions that should precede a wholesale adoption of…

Report of the Defense Science Board Task Force on Future Strategic Strike Skills

DTIC Science & Technology

2006-03-01

25 Figure 11: Re - entry Systems – Critical Skills...SKILLS___________________________________________________25 Figure 9: Guidance – Critical Skills Figure 10: Re - entry Systems – Critical Skills ICBMS/BASING...ability to survive intercontinental ballistic missile re - entry and then to operate effectively thereafter, is another area where current skills are

Critical Teacher Education and the Politics of Teacher Accreditation: Are We Practicing What We Preach?

ERIC Educational Resources Information Center

Aronson, Brittany; Anderson, Ashlee

2013-01-01

With this article, we challenge the successful implementation of critical perspectives in an increasingly neoliberal and neoconservative educational climate. Although many teacher education programs challenge teachers to be critical and to empower students, current top-down accountability practices and policy mandates do not allow teachers the…

In Defense of Graphic Novels

ERIC Educational Resources Information Center

Hansen, Kathryn Strong

2012-01-01

In the 18th century, critics grumbled about a new literary form that supposedly threatened the abilities of youth to distinguish between reality and artificiality. This form was the novel, one of the literary forms that critics now hold dearest. Currently, the graphic novel receives a great deal of criticism. Yet many teachers have shown how…

The Construction of Cultural Values and Beliefs in Chinese Language Textbooks: A Critical Discourse Analysis

ERIC Educational Resources Information Center

Liu, Yongbing

2005-01-01

This article examines the discourses of cultural values and beliefs constructed in Chinese language textbooks currently used for primary school students nationwide in China. By applying story grammar analysis in the framework of critical discourse analysis, the article critically investigates how the discourses are constructed and what ideological…

Milgram's Obedience Study: A Contentious Classic Reinterpreted

ERIC Educational Resources Information Center

Griggs, Richard A.

2017-01-01

Given the many older criticisms of Milgram's obedience study and the more damning recent criticisms based on analyses of materials available in the Milgram archives at Yale, this study has become a contentious classic. Yet, current social psychology textbooks present it as an uncontentious classic, with no coverage of the recent criticisms and…

Critical Thinking as Miracle Tonic: Selling Snake Oil in Education.

ERIC Educational Resources Information Center

Hyslop-Margison, Emery J.

This paper proposes that the current interest in critical thinking is based on important conceptual, epistemological, and procedural confusions. It suggests that the attempt to identify a successful critical thinking construct mirrors the search for miracle tonics often peddled by snake oil salesmen as a medicinal cure-all. It goes to suggest that…

Nonequilibrium Phase Transitions and a Nonequilibrium Critical Point from Anti-de Sitter Space and Conformal Field Theory Correspondence

NASA Astrophysics Data System (ADS)

Nakamura, Shin

2012-09-01

We find novel phase transitions and critical phenomena that occur only outside the linear-response regime of current-driven nonequilibrium states. We consider the strongly interacting (3+1)-dimensional N=4 large-Nc SU(Nc) supersymmetric Yang-Mills theory with a single flavor of fundamental N=2 hypermultiplet as a microscopic theory. We compute its nonlinear nonballistic quark-charge conductivity by using the AdS/CFT correspondence. We find that the system exhibits a novel nonequilibrium first-order phase transition where the conductivity jumps and the sign of the differential conductivity flips at finite current density. A nonequilibrium critical point is discovered at the end point of the first-order regime. We propose a nonequilibrium steady-state analogue of thermodynamic potential in terms of the gravity-dual theory in order to define the transition point. Nonequilibrium analogues of critical exponents are proposed as well. The critical behavior of the conductivity is numerically confirmed on the basis of these proposals. The present work provides a new example of nonequilibrium phase transitions and nonequilibrium critical points.

Comparison study of cable geometries and superconducting tape layouts for high-temperature superconductor cables

NASA Astrophysics Data System (ADS)

Ta, Wurui; Shao, Tianchong; Gao, Yuanwen

2018-04-01

High-temperature superconductor (HTS) rare-earth-barium-copper-oxide (REBCO) tapes are very promising for use in high-current cables. The cable geometry and the layout of the superconducting tapes are directly related to the performance of the HTS cable. In this paper, we use numerical methods to perform a comparison study of multiple-stage twisted stacked-tape cable (TSTC) conductors to find better cable structures that can both improve the critical current and minimize the alternating current (AC) losses of the cable. The sub-cable geometry is designed to have a stair-step shape. Three superconducting tape layouts are chosen and their transport performance and AC losses are evaluated. The magnetic field and current density profiles of the cables are obtained. The results show that arrangement of the superconducting tapes from the interior towards the exterior of the cable based on their critical current values in descending order can enhance the cable's transport capacity while significantly reducing the AC losses. These results imply that cable transport capacity improvements can be achieved by arranging the superconducting tapes in a manner consistent with the electromagnetic field distribution. Through comparison of the critical currents and AC losses of four types of HTS cables, we determine the best structural choice among these cables.

[Telemedicine: Improving the quality of care for critical patients from the pre-hospital phase to the intensive care unit].

PubMed

Murias, G; Sales, B; García-Esquirol, O; Blanch, L

2010-01-01

The Health System is in crisis and critical care (from transport systems to the ICU) cannot escape from that. Lack of integration between ambulances and reference Hospitals, a deep shortage of critical care specialists and assigned economical resources that increase less than critical care demand are the cornerstones of the problem. Moreover, the analysis of the situation anticipated that the problem will be worse in the future. "Closed" ICUs in which critical care specialists direct patient care outperform "open" ones in which primary admitting physicians direct patient care in consultation with critical care specialists. However, the current paradigm in which a critical care specialist is close to the patient is in the edge of the trouble so, only a new paradigm could help to increase the number of patients under intensivist care. Current information technology and networking capabilities should be fully exploited to improve both the extent and quality of intensivist coverage. Far to be a replacement of the existing model Telemedicine might be a complimentary tool. In fact, to centralize medical data into servers has many additional advantages that could even improve the way in which critical care physicians take care of their patients under the traditional system. Copyright 2009 Elsevier España, S.L. y SEMICYUC. All rights reserved.

Two ways to model voltage current curves of adiabatic MgB2 wires

NASA Astrophysics Data System (ADS)

Stenvall, A.; Korpela, A.; Lehtonen, J.; Mikkonen, R.

2007-08-01

Usually overheating of the sample destroys attempts to measure voltage-current curves of conduction cooled high critical current MgB2 wires at low temperatures. Typically, when a quench occurs a wire burns out due to massive heat generation and negligible cooling. It has also been suggested that high n values measured with MgB2 wires and coils are not an intrinsic property of the material but arise due to heating during the voltage-current measurement. In addition, quite recently low n values for MgB2 wires have been reported. In order to find out the real properties of MgB2 an efficient computational model is required to simulate the voltage-current measurement. In this paper we go back to basics and consider two models to couple electromagnetic and thermal phenomena. In the first model the magnetization losses are computed according to the critical state model and the flux creep losses are considered separately. In the second model the superconductor resistivity is described by the widely used power law. Then the coupled current diffusion and heat conduction equations are solved with the finite element method. In order to compare the models, example runs are carried out with an adiabatic slab. Both models produce a similar significant temperature rise near the critical current which leads to fictitiously high n values.

Nonequilibrium Second-Order Phase Transition in a Cooper-Pair Insulator.

PubMed

Doron, A; Tamir, I; Mitra, S; Zeltzer, G; Ovadia, M; Shahar, D

2016-02-05

In certain disordered superconductors, upon increasing the magnetic field, superconductivity terminates with a direct transition into an insulating phase. This phase is comprised of localized Cooper pairs and is termed a Cooper-pair insulator. The current-voltage characteristics measured in this insulating phase are highly nonlinear and, at low temperatures, exhibit abrupt current jumps. Increasing the temperature diminishes the jumps until the current-voltage characteristics become continuous. We show that a direct correspondence exists between our system and systems that undergo an equilibrium, second-order, phase transition. We illustrate this correspondence by comparing our results to the van der Waals equation of state for the liquid-gas mixture. We use the similarities to identify a critical point where an out of equilibrium second-order-like phase transition occurs in our system. Approaching the critical point, we find a power-law behavior with critical exponents that characterizes the transition.

An exponential scaling law for the strain dependence of the Nb3Sn critical current density

NASA Astrophysics Data System (ADS)

Bordini, B.; Alknes, P.; Bottura, L.; Rossi, L.; Valentinis, D.

2013-07-01

The critical current density of the Nb3Sn superconductor is strongly dependent on the strain applied to the material. In order to investigate this dependence, it is a common practice to measure the critical current of Nb3Sn strands for different values of applied axial strain. In the literature, several models have been proposed to describe these experimental data in the reversible strain region. All these models are capable of fitting the measurement results in the strain region where data are collected, but tend to predict unphysical trends outside the range of data, and especially for large strain values. In this paper we present a model of a new strain function, together with the results obtained by applying the new scaling law on relevant datasets. The data analyzed consisted of the critical current measurements at 4.2 K that were carried out under applied axial strain at Durham University and the University of Geneva on different strand types. With respect to the previous models proposed, the new scaling function does not present problems at large strain values, has a lower number of fitting parameters (only two instead of three or four), and is very stable, so that, starting from few experimental points, it can estimate quite accurately the strand behavior in a strain region where there are no data. A relationship is shown between the proposed strain function and the elastic strain energy, and an analogy is drawn with the exponential form of the McMillan equation for the critical temperature.

High temperature superconducting fault current limiter

DOEpatents

Hull, J.R.

1997-02-04

A fault current limiter for an electrical circuit is disclosed. The fault current limiter includes a high temperature superconductor in the electrical circuit. The high temperature superconductor is cooled below its critical temperature to maintain the superconducting electrical properties during operation as the fault current limiter. 15 figs.

The fact of ignorance: revisiting the Socratic method as a tool for teaching critical thinking.

PubMed

Oyler, Douglas R; Romanelli, Frank

2014-09-15

Critical thinking, while highly valued as an ability of health care providers, remains a skill that many educators find difficult to teach. This review provides an analysis examining why current methods of teaching critical thinking to health care students (primarily medical and pharmacy students) often fail and describes a premise and potential utility of the Socratic method as a tool to teach critical thinking in health care education.

Longitudinal Proximity Effects in Superconducting Transition-Edge Sensors

NASA Technical Reports Server (NTRS)

Sadleir, John E.; Smith, Stephen J.; Bandler, SImon R.; Chervenak, James A.; Clem, John R.

2009-01-01

We have found experimentally that the critical current of a square superconducting transition-edge sensor (TES) depends exponentially upon the side length L and the square root of the temperature T. As a consequence, the effective transition temperature T(sub c) of the TES is current-dependent and at fixed current scales as 1/L(sup 2). We also have found that the critical current can show clear Fraunhofer-like oscillations in an applied magnetic field, similar to those found in Josephson junctions. The observed behavior has a natural theoretical explanation in terms of longitudinal proximity effects if the TES is regarded as a weak link between superconducting leads. We have observed the proximity effect in these devices over extraordinarily long lengths exceeding 100 microns.

Temperature dependence of critical current and transport current losses of 4 mm YBCO coated conductors manufactured using nonmagnetic substrate

NASA Astrophysics Data System (ADS)

Kvitkovic, J.; Hatwar, R.; Pamidi, S. V.; Fleshler, S.; Thieme, C.

2015-12-01

The temperature dependence of the critical current and AC losses were measured on American Superconductor Corporation's (AMSC) second generation high temperature superconducting (2G HTS) wire produced by Rolling Assisted Biaxially Textured Substrate (RABiTS) and Metal Organic Deposition (MOD) process. Wires manufactured with two types of substrates were characterized. The magnetic substrate with composition Ni5a%W exhibits a magnetic signature and has non-negligible AC losses in AC power applications. A new nonmagnetic substrate with an alloy composition Ni9a%W has been developed by AMSC to address the AC losses in 2G HTS. The data presented show that the performance of the new conductor is identical to the conductor with magnetic substrate in terms of critical current density. The data on AC losses demonstrate the absence of ferromagnetic loss component in the new conductor and significantly reduced AC losses at low to moderate values of I/Ic. The reduced losses will translate into reduced capital costs and lower operating costs of superconducting electrical devices for AC applications.

Implications of Weak-Link Behavior on the Performance of Mo/Au Bilayer Transition-Edge Sensors

NASA Technical Reports Server (NTRS)

Smith, Stephen J.

2011-01-01

Understanding the physical properties of the superconducting-to-normal transition is fundamental for optimizing the design and performance of transition-edge sensors (TESs). Recent critical current measurements of Mol Au bilayer test structures show that they act as weak superconducting links, exhibiting oscillatory, Fraunhofer-like behavior with applied magnetic field. In this paper we investigate the implications of this behavior for TES X-ray detectors, under operational bias conditions. These devices include normal metal features used for absorber attachment and unexplained noise suppression, which result in modifications to the previously reported critical current behavior. We present measurements of the logarithmic resistance sensitivity with temperature, a, and current, b, as a function of applied magnetic field and bias point within the resistive transition. Results show that these important device parameters exhibit similar oscillatory behavior with applied magnetic field, which in turn affects the signal responsivity and noise, and hence the energy resolution. These results show the significance of the critical current in determining the performance of TESs and hold promise to improve future.

Free flux flow in two single crystals of V3Si with slightly different pinning strengths

NASA Astrophysics Data System (ADS)

Gafarov, O.; Gapud, A. A.; Moraes, S.; Thompson, J. R.; Christen, D. K.; Reyes, A. P.

2010-10-01

Results of recent measurements on two very clean, single-crystal samples of the A15 superconductor V3Si are presented. Magnetization and transport data already confirmed the ``clean'' quality of both samples, as manifested by: (i) high residual resistivity ratio, (ii) very low critical current densities, and (iii) a ``peak'' effect in the field dependence of critical current. The (H,T) phase line for this peak effect is shifted in the slightly ``dirtier'' sample, which consequently also has higher critical current density Jc(H). High-current Lorentz forces are applied on mixed-state vortices in order to induce the highly ordered free flux flow (FFF) phase, using the same methods as in previous work. A traditional model by Bardeen and Stephen (BS) predicts a simple field dependence of flux flow resistivity ρf(H), presuming a field-independent flux core size. A model by Kogan and Zelezhina (KZ) takes core size into account, and predict a clear deviation from BS. In this study, ρf(H) is confirmed to be consistent with predictions of KZ, as will be discussed.

Critical Thinking Skills among Elementary School Students: Comparing Identified Gifted and General Education Student Performance

ERIC Educational Resources Information Center

Kettler, Todd

2014-01-01

Education reform efforts, including the current adoption of Common Core State Standards, have increased attention to teaching critical thinking skills to all students. This study investigated the critical thinking skills of fourth-grade students from a school district in Texas, including 45 identified gifted students and 163 general education…

Critical Pedagogy Enacted in the Gay-Straight Alliance: New Possibilities for a Third Space in Teacher Development

ERIC Educational Resources Information Center

Mayo, J. B., Jr.

2013-01-01

Critical pedagogy, combined with partnerships with adults at school, enabled the Gay-Straight Alliance (GSA) advisor to create the foundation for reflective, activist-oriented learning at one Midwestern high school. Underreported in current literature, the use of critical pedagogy in school clubs and/or organizations has broad implications for…

Double Infusion: Toward a Process of Articulation between Critical Multicultural Education and Technology Education in a Teacher Preparation Program

ERIC Educational Resources Information Center

McShay, James

2005-01-01

This paper describes the goals of critical multicultural education in the USA and identifies current challenges working to impede its infusion within technology teacher education programs. It offers both technology and multicultural teacher educators a model for infusion of both critical multicultural perspectives and technology into their…

Teacher Educators as Cultural Workers: Problematizing Teacher Education Pedagogies

ERIC Educational Resources Information Center

de los Ríos, Cati; Souto-Manning, Mariana

2015-01-01

From a Latina/o Critical Race Theory perspective, in this article we engage in a process of testimonio co-creation to trace Freire's notion of critical pedagogy in our lives as former schoolteachers and current teacher educators. Through the critical analysis of our lived experiences, we unveil the powerful affordances we have gained by employing…

About the Reflective Thought Also Known as the Critical Thinking

ERIC Educational Resources Information Center

León, Federico R.

2014-01-01

This article deals with the concept of reflective thought or critical thinking from its initial formulation as an intellectual attitude to its current articulation as a third level of cognitive processing. Issues dealt with include critical thinking as a goal, as a cognitive process, as a part of dual cognitive processes, as a measurable…

Giant increase in critical current density of K xFe 2-ySe₂ single crystals

DOE PAGES

Lei, Hechang; Petrovic, C.

2011-12-28

The critical current density Jabc of K xFe 2-ySe₂ single crystals can be enhanced by more than one order of magnitude, up to ~2.1×10⁴ A/cm² by the post annealing and quenching technique. A scaling analysis reveals the universal behavior of the normalized pinning force as a function of the reduced field for all temperatures, indicating the presence of a single vortex pinning mechanism. The main pinning sources are three-dimensional (3D) point-like normal cores. The dominant vortex interaction with pinning centers is via spatial variations in critical temperature T c (“δT c pinning”).

Integration of simulation in postgraduate studies in Saudi Arabia: The current practice in anesthesia training program

PubMed Central

Arab, Abeer; Alatassi, Abdulaleem; Alattas, Elias; Alzoraigi, Usamah; AlZaher, Zaki; Ahmad, Abdulaziz; Albabtain, Hesham; Boker, Abdulaziz

2017-01-01

The educational programs in the Saudi Commission for Health Specialties are developing rapidly in the fields of technical development. Such development is witnessed, particularly in the scientific areas related to what is commonly known as evidence-based medicine. This review highlights the critical need and importance of integrating simulation into anesthesia training and assessment. Furthermore, it describes the current utilization of simulation in anesthesia and critical care assessment process. PMID:28442961

Studies of the Superconducting Transition in the Mo/Au-Bilayer Thin Films

NASA Technical Reports Server (NTRS)

Sadleir, John; Smith, Stephen; Iyomoto, naoko; Bandler, Simon; Chervenak, Jay; Brown, Ari; Brekowsky, Regis; Kilbourne, Caroline; Robinson, Ian

2007-01-01

At NASA Goddard, microcalorimeter arrays using superconducting transition edge sensor thermometers (TESs) are under development for high energy resolution X-ray astrophysics applications. We report on our studies of the superconducting transition in our Mo/Au-bilayer TES films including: low current measurements of the superconducting bilayer's resistance transition versus temperature on pixels with different normal metal absorber attachment designs and measured temperature scaling of the critical current and critical magnetic field.

Making High-Temperature Superconductors By Melt Sintering

NASA Technical Reports Server (NTRS)

Golben, John P.

1992-01-01

Melt-sintering technique applied to YBa2Cu3O7-x system and to Bi/Ca/Sr/Cu-oxide system to produce highly oriented bulk high-temperature-superconductor materials extending to macroscopically usable dimensions. Processing requires relatively inexpensive and simple equipment. Because critical current two orders of magnitude greater in crystal ab plane than in crystal c direction, high degree of orientation greatly enhances critical current in these bulk materials, making them more suitable for many proposed applications.

Progress Report for Grant Number W911NF-09-1-0347 (University of Illinois - Urbana)

DTIC Science & Technology

2012-11-06

critical tunneling current is proportional to mexc, we find good agreement with this explanation via the approximate square-root dependence seen in Fig...can occur near the contact, reducing interlayer conductivity significantly. As critical tunneling current is linearly dependent on the width of the...studied the possibility of finding the same type of condensation in a 3D topological insulator, and started our work on a time- dependent theory to

Current IT Issues, 2004

ERIC Educational Resources Information Center

Spicer, Donald Z.; Deblois, Peter B.

2004-01-01

This article features the EDUCAUSE Current Issues Survey. Administered by the EDUCAUSE Current Issues Committee, whose members review and recommend the set of issues to be presented each year, the survey identifies the issues that leaders in higher education information technology see as their most critical IT challenges. The Top-Ten current IT…

High temperature superconducting fault current limiter

DOEpatents

Hull, John R.

1997-01-01

A fault current limiter (10) for an electrical circuit (14). The fault current limiter (10) includes a high temperature superconductor (12) in the electrical circuit (14). The high temperature superconductor (12) is cooled below its critical temperature to maintain the superconducting electrical properties during operation as the fault current limiter (10).

Validation of Finite-Element Models of Persistent-Current Effects in Nb 3Sn Accelerator Magnets

DOE PAGES

Wang, X.; Ambrosio, G.; Chlachidze, G.; ...

2015-01-06

Persistent magnetization currents are induced in superconducting filaments during the current ramping in magnets. The resulting perturbation to the design magnetic field leads to field quality degradation, in particular at low field where the effect is stronger relative to the main field. The effects observed in NbTi accelerator magnets were reproduced well with the critical-state model. However, this approach becomes less accurate for the calculation of the persistent-current effects observed in Nb 3Sn accelerator magnets. Here a finite-element method based on the measured strand magnetization is validated against three state-of-art Nb3Sn accelerator magnets featuring different subelement diameters, critical currents, magnetmore » designs and measurement temperatures. The temperature dependence of the persistent-current effects is reproduced. Based on the validated model, the impact of conductor design on the persistent current effects is discussed. The performance, limitations and possible improvements of the approach are also discussed.« less

Shielding and flux trapping properties of high temperature superconductors in the shape of hollow cylinders

NASA Technical Reports Server (NTRS)

Israelsson, U. E.; Strayer, D. M.

1991-01-01

Allowing for a field-dependent critical current density, the authors calculate the magnetic field that can be supported by hollow cylinders of varying wall thickness. An adiabatically stable field of 1.0 T can be shielded by or trapped in a cylinder with a wall thickness of 0.4 cm if the critical current density varies linearly with magnetic field and has a value of 104 A/sq cm at a field of 1.0 T. Such a current density appears to be within reach of present state-of-the-art melt-processed YBa2Cu3O7 (123) materials.

Peculiarities of field penetration in the presence of cross-flux interaction

NASA Astrophysics Data System (ADS)

Berseth, V.; Buzdin, A. I.; Indenbom, M. V.; Benoit, W.

1996-02-01

The attractive core interaction between two orthogonal vortex lattices in alayered superconductor is calculated. When one of these lattices is moving, this interaction gives rise to a drag force acting on the other one. Considering a moving in-plane flux lattice, the effect of the drag force on the perpendicular flux is modelled through a modification of the bulk critical current for this field component. The new critical current depends on the direction of motion of both parallel and perpendicular vortices. The results are derived within the critical-state model for the infinite slab and for the thin strip. For this latter geometry, computations are made with the help of a new numerical method simulating flux penetration in the critical state. The new predicted qualitative phenomena (like the formation of a vortex-free region between two zones of opposite flux in the flat geometry) can be directly verified by the magneto-optic technique.

Magnetization Analysis of Magnesium Boride Wires

NASA Astrophysics Data System (ADS)

Cave, J. R.; Zhu, W.

2006-03-01

Cycled applied field magnetization curves contain a wealth of information on critical current density and flux pinning that is not commonly exploited. Detailed magnetization data for magnesium boride wire cores have been analyzed for critical state model consistency. The iron-sheathed silicon nitride doped magnesium boride wires were prepared from pure magnesium and boron powders with nano-scale silicon nitride additions (MgB2-x(Si3N4)x/7 with x = 0 - 0.4). A subsequent short annealing heat treatment, 800 degrees C and of 1 hour duration in Argon, was applied to create the desired phase. Magnetization critical current densities were up to ˜340 kA/cm2 at 5K and 1T. Major and minor loop analysis will be described, for field sweeps up to 3 tesla at fixed temperatures and for temperature sweeps from 5K to 45K in fixed fields, with respect to parameters describing the critical state model.

Effect of partially ionized impurities and radiation on the effective critical electric field for runaway generation

NASA Astrophysics Data System (ADS)

Hesslow, L.; Embréus, O.; Wilkie, G. J.; Papp, G.; Fülöp, T.

2018-07-01

We derive a formula for the effective critical electric field for runaway generation and decay that accounts for the presence of partially ionized impurities in combination with synchrotron and bremsstrahlung radiation losses. We show that the effective critical field is drastically larger than the classical Connor–Hastie field, and even exceeds the value obtained by replacing the free electron density by the total electron density (including both free and bound electrons). Using a kinetic equation solver with an inductive electric field, we show that the runaway current decay after an impurity injection is expected to be linear in time and proportional to the effective critical electric field in highly inductive tokamak devices. This is relevant for the efficacy of mitigation strategies for runaway electrons since it reduces the required amount of injected impurities to achieve a certain current decay rate.

Critical current measurements of high-temperature superconducting short samples at a wide range of temperatures and magnetic fields.

PubMed

Ma, Hongjun; Liu, Huajun; Liu, Fang; Zhang, Huahui; Ci, Lu; Shi, Yi; Lei, Lei

2018-01-01

High-Temperature Superconductors (HTS) are potential materials for high-field magnets, low-loss transmission cables, and Superconducting Magnetic Energy Storage (SMES) due to their high upper critical magnetic field (H c2 ) and critical temperature (T c ). The critical current (I c ) of HTS, which is one of the most important parameters for superconductor application, depends strongly on the magnetic fields and temperatures. A new I c measurement system that can carry out accurate I c measurement for HTS short samples with various temperatures (4.2-80 K), magnetic fields (0-14 T), and angles of the magnetic field (0°-90°) has been developed. The I c measurement system mainly consists of a measurement holder, temperature-control system, background magnet, test cryostat, data acquisition system, and DC power supply. The accuracy of temperature control is better than ±0.1 K over the 20-80 K range and ±0.05 K when measured below 20 K. The maximum current is over 1000 A with a measurement uncertainty of 1%. The system had been successfully used for YBa 2 Cu 3 O 7-x (YBCO) tapes I c determination with different temperatures and magnetic fields.

Critical current measurements of high-temperature superconducting short samples at a wide range of temperatures and magnetic fields

NASA Astrophysics Data System (ADS)

Ma, Hongjun; Liu, Huajun; Liu, Fang; Zhang, Huahui; Ci, Lu; Shi, Yi; Lei, Lei

2018-01-01

High-Temperature Superconductors (HTS) are potential materials for high-field magnets, low-loss transmission cables, and Superconducting Magnetic Energy Storage (SMES) due to their high upper critical magnetic field (Hc2) and critical temperature (Tc). The critical current (Ic) of HTS, which is one of the most important parameters for superconductor application, depends strongly on the magnetic fields and temperatures. A new Ic measurement system that can carry out accurate Ic measurement for HTS short samples with various temperatures (4.2-80 K), magnetic fields (0-14 T), and angles of the magnetic field (0°-90°) has been developed. The Ic measurement system mainly consists of a measurement holder, temperature-control system, background magnet, test cryostat, data acquisition system, and DC power supply. The accuracy of temperature control is better than ±0.1 K over the 20-80 K range and ±0.05 K when measured below 20 K. The maximum current is over 1000 A with a measurement uncertainty of 1%. The system had been successfully used for YBa2Cu3O7-x(YBCO) tapes Ic determination with different temperatures and magnetic fields.

The Fact of IgnoranceRevisiting the Socratic Method as a Tool for Teaching Critical Thinking

PubMed Central

Romanelli, Frank

2014-01-01

Critical thinking, while highly valued as an ability of health care providers, remains a skill that many educators find difficult to teach. This review provides an analysis examining why current methods of teaching critical thinking to health care students (primarily medical and pharmacy students) often fail and describes a premise and potential utility of the Socratic method as a tool to teach critical thinking in health care education. PMID:25258449

High-field superconductivity in the Nb-Ti-Zr ternary system

NASA Astrophysics Data System (ADS)

Ralls, K. M.; Rose, R. M.; Wulff, J.

1980-06-01

Resistive critical current densities, critical fields, and normal-state electrical resistivities were obtained at 4.2 °K for 55 alloys in the Nb-Ti-Zr ternary alloy system, excepting Ti-Zr binary compositions. The resistive critical field as a function of ternary composition has a saddle point between the Nb-Ti and Nb-Zr binaries, so that ternary alloying in this system is not expected to result in higher critical fields than the binary alloys.

Rationing critical care medicine: recent studies and current trends.

PubMed

Ward, Nicholas S

2005-12-01

This paper reviews the literature on the rationing of critical care resources. Although much has been written about the concept of rationing, there have been few scientific studies as to its prevalence. A recent meta-analysis reviewed all previously published studies on rationing access to intensive care units but little is known about practices within the intensive care unit. Much literature in the past few years has focused on the growing use of critical care resources and projections for the future. Several authors suggest there may be a crisis in financial or personnel resources if some rationing does not take place. Other papers have argued that the methods of rationing critical care previously proposed, such as limiting the care of dying patients or using cost-effectiveness analysis to determine care, may not be effective or viewed as ethical by some. Finally, several recent papers review how critical care is practiced and allocated in India and Asian countries that already practice open rationing in their health care systems. There is currently no published evidence that overt rationing is taking place in critical care medicine. There is growing evidence that in the future, the need for critical care may outstrip financial resources unless some form of rationing takes place. It is also clear from the literature that choosing how to ration critical care will be a difficult task.

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

NASA Astrophysics Data System (ADS)

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.

Using change-point models to estimate empirical critical loads for nitrogen in mountain ecosystems.

PubMed

Roth, Tobias; Kohli, Lukas; Rihm, Beat; Meier, Reto; Achermann, Beat

2017-01-01

To protect ecosystems and their services, the critical load concept has been implemented under the framework of the Convention on Long-range Transboundary Air Pollution (UNECE) to develop effects-oriented air pollution abatement strategies. Critical loads are thresholds below which damaging effects on sensitive habitats do not occur according to current knowledge. Here we use change-point models applied in a Bayesian context to overcome some of the difficulties when estimating empirical critical loads for nitrogen (N) from empirical data. We tested the method using simulated data with varying sample sizes, varying effects of confounding variables, and with varying negative effects of N deposition on species richness. The method was applied to the national-scale plant species richness data from mountain hay meadows and (sub)alpine scrubs sites in Switzerland. Seven confounding factors (elevation, inclination, precipitation, calcareous content, aspect as well as indicator values for humidity and light) were selected based on earlier studies examining numerous environmental factors to explain Swiss vascular plant diversity. The estimated critical load confirmed the existing empirical critical load of 5-15 kg N ha -1 yr -1 for (sub)alpine scrubs, while for mountain hay meadows the estimated critical load was at the lower end of the current empirical critical load range. Based on these results, we suggest to narrow down the critical load range for mountain hay meadows to 10-15 kg N ha -1 yr -1 . Copyright © 2016 Elsevier Ltd. All rights reserved.

A novel modeling to predict the critical current behavior of Nb3Sn PIT strand under transverse load based on a scaling law and Finite Element Analysis

NASA Astrophysics Data System (ADS)

Wang, Tiening; Chiesa, Luisa; Takayasu, Makoto; Bordini, Bernardo

2014-09-01

Superconducting Nb3Sn Powder-In-Tube (PIT) strands could be used for the superconducting magnets of the next generation Large Hadron Collider. The strands are cabled into the typical flat Rutherford cable configuration. During the assembly of a magnet and its operation the strands experience not only longitudinal but also transverse load due to the pre-compression applied during the assembly and the Lorentz load felt when the magnets are energized. To properly design the magnets and guarantee their safe operation, mechanical load effects on the strand superconducting properties are studied extensively; particularly, many scaling laws based on tensile load experiments have been established to predict the critical current dependence on strain. However, the dependence of the superconducting properties on transverse load has not been extensively studied so far. One of the reasons is that transverse loading experiments are difficult to conduct due to the small diameter of the strand (about 1 mm) and the data currently available do not follow a common measurement standard making the comparison between different data sets difficult. Recently at the University of Geneva, a new device has been developed to characterize the critical current of Nb3Sn strands under transverse loads. In this work we present a new 2D Finite Element Analysis (FEA) to predict the electro-mechanical response of a PIT strand that was tested at the University of Geneva when transverse load is applied. The FEA provides the strain map for the superconducting filaments when the load is applied. Those strain maps are then used to evaluate the critical current behavior of a PIT strand using a recently developed scaling law that correlates the superconducting properties of a wire with the strain invariants due to the load applied on the superconductor. The benefits and limitations of this method are discussed based on the comparison between the critical current simulation results obtained with the filament strain map and the experimental results available for PIT strands.

Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

DTIC Science & Technology

2013-06-10

subcritical; that is, no critical mass is formed and no self-sustaining nuclear chain reaction can occur; thus, there is no nuclear explosion.”211 SCEs...45 The National Academy of Sciences Study and Its Critics ...the future, but there are no plans to do so.”8 Critics expressed concern about the implications of these policies for testing and new weapons

Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

DTIC Science & Technology

2012-08-03

Academy of Sciences Study and Its Critics ....................................................... 39 Chronology... criticisms of that report. On February 13, the Administration rolled out its FY2013 budget request, which included funds for the CTBT Organization...So he has not ruled out testing in the future, but there are no plans to do so.”4 Critics expressed concern about the implications of these policies

The Effectiveness of the Master Thinker Program in Developing Critical Thinking Skills of 11th Grade Students in Bahrain

ERIC Educational Resources Information Center

Alnabhan, Mousa; Alhamdan, Najat; Darwish, Ahmed

2014-01-01

The current study aimed at investigating the effect of the Master Thinker program on developing critical thinking skills of 11th grade students in Bahrain. Specifically, this research attempts to examine the hypothesis: Teaching the Master Thinker program will be significantly effective in developing critical thinking and its skills (inference,…

Exploring Saudi Pre-Service Teachers' Knowledge of Critical Thinking Skills and Their Teaching Perceptions

ERIC Educational Resources Information Center

Gashan, Amani K.

2015-01-01

The current study aimed to investigate Saudi pre-service teachers' knowledge about the general concepts of critical thinking, as well as its skills. In addition, the study explored their perceptions about critical thinking and its teaching in classrooms with an aim to develop learning and teaching process. The study was conducted with twenty-nine…

Exploring the Literature on Music Participation and Social Connectedness for Young People with Intellectual Disability: A Critical Interpretive Synthesis

ERIC Educational Resources Information Center

Murphy, Melissa A. I.; McFerran, Katrina

2017-01-01

Background: This article explores the literature on social connectedness and music for young people with disability. It then critically examines the level of congruence between the reported literature to date and current rights-based disability studies discourse. Method: A critical interpretive synthesis was used to examine 27 articles referencing…

The Practice and Challenges of Implementing Critical Thinking Skills in Omani Post-Basic EFL Classrooms

ERIC Educational Resources Information Center

Al-Kindi, Naeema Saleh; AL-Mekhlafi, Abdo Mohammed

2017-01-01

The purpose of the current study is to investigate post-basic English teachers' practice of critical thinking skills and the challenges they face while teaching skills in EFL classrooms. Three research questions were investigated to achieve this purpose: 1--To what extent do EFL teachers use classroom behaviors that nurture critical thinking at…

A conceptual framework: redifining forests soil's critical acid loads under a changing climate

Treesearch

Steven G. McNulty; Johnny L. Boggs

2010-01-01

Federal agencies of several nations have or are currently developing guidelines for critical forest soil acid loads. These guidelines are used to establish regulations designed to maintain atmospheric acid inputs below levels shown to damage forests and streams. Traditionally, when the critical soil acid load exceeds the amount of acid that the ecosystem can absorb, it...

Linking nursing theory and practice: a critical-feminist approach.

PubMed

Georges, Jane M

2005-01-01

Situated in a critical-feminist perspective, this article describes a pedagogical approach to linking nursing theory and practice. The inclusion of the critical humanities is emphasized in creating an environment in which this linkage can be reified for learners. Implications for the future of nursing theory and its links to practice in the context of current political realities in academia are considered.

Programs to Locate Missing and Critically Wandering Elders: A Critical Review and a Call for Multiphasic Evaluation

ERIC Educational Resources Information Center

Petonito, Gina; Muschert, Glenn W.; Carr, Dawn C.; Kinney, Jennifer M.; Robbins, Emily J.; Brown, J. Scott

2013-01-01

As America ages, greater numbers of older adults will be living with Alzheimer's disease or a related dementia, leading to increased incidence of wandering. Currently there are several initiatives to assist older adults who go missing. We describe and critically examine three prominent and widespread programs: Safe Return, Project Lifesaver, and…

Teaching Critical Reading through Set Theory. Working Paper No. 20.

ERIC Educational Resources Information Center

Scott, Michael R.; And Others

This paper examines the context of critical reading and considers how it can best be taught. The paper also includes some reflections on the current "state of the art" in critical reading in an English for Special Purposes (ESP) or English as a Second Language (ESL) context. The paper details a series of attempts to develop a set of…

Progress on core outcome sets for critical care research.

PubMed

Blackwood, Bronagh; Marshall, John; Rose, Louise

2015-10-01

Appropriate selection and definition of outcome measures are essential for clinical trials to be maximally informative. Core outcome sets (an agreed, standardized collection of outcomes measured and reported in all trials for a specific clinical area) were developed due to established inconsistencies in trial outcome selection. This review discusses the rationale for, and methods of, core outcome set development, as well as current initiatives in critical care. Recent systematic reviews of reported outcomes and measurement instruments relevant to the critically ill highlight inconsistencies in outcome selection, definition, and measurement, thus establishing the need for core outcome sets. Current critical care initiatives include development of core outcome sets for trials aimed at reducing mechanical ventilation duration; rehabilitation following critical illness; long-term outcomes in acute respiratory failure; and epidemic and pandemic studies of severe acute respiratory infection. Development and utilization of core outcome sets for studies relevant to the critically ill is in its infancy compared to other specialties. Notwithstanding, core outcome set development frameworks and guidelines are available, several sets are in various stages of development, and there is strong support from international investigator-led collaborations including the International Forum for Acute Care Trialists.

Applying the cell-based coagulation model in the management of critical bleeding.

PubMed

Ho, K M; Pavey, W

2017-03-01

The cell-based coagulation model was proposed 15 years ago, yet has not been applied commonly in the management of critical bleeding. Nevertheless, this alternative model may better explain the physiological basis of current coagulation management during critical bleeding. In this article we describe the limitations of the traditional coagulation protein cascade and standard coagulation tests, and explain the potential advantages of applying the cell-based model in current coagulation management strategies. The cell-based coagulation model builds on the traditional coagulation model and explains many recent clinical observations and research findings related to critical bleeding unexplained by the traditional model, including the encouraging results of using empirical 1:1:1 fresh frozen plasma:platelets:red blood cells transfusion strategy, and the use of viscoelastic and platelet function tests in patients with critical bleeding. From a practical perspective, applying the cell-based coagulation model also explains why new direct oral anticoagulants are effective systemic anticoagulants even without affecting activated partial thromboplastin time or the International Normalized Ratio in a dose-related fashion. The cell-based coagulation model represents the most cohesive scientific framework on which we can understand and manage coagulation during critical bleeding.

Key factors of eddy current separation for recovering aluminum from crushed e-waste.

PubMed

Ruan, Jujun; Dong, Lipeng; Zheng, Jie; Zhang, Tao; Huang, Mingzhi; Xu, Zhenming

2017-02-01

Recovery of e-waste in China had caused serious pollutions. Eddy current separation is an environment-friendly technology of separating nonferrous metallic particles from crushed e-waste. However, due to complex particle characters, separation efficiency of traditional eddy current separator was low. In production, controllable operation factors of eddy current separation are feeding speed, (ωR-v), and S p . There is little special information about influencing mechanism and critical parameters of these factors in eddy current separation. This paper provided the special information of these key factors in eddy current separation of recovering aluminum particles from crushed waste refrigerator cabinets. Detachment angles increased as the increase of (ωR-v). Separation efficiency increased with the growing of detachment angles. Aluminum particles were completely separated from plastic particles in critical parameters of feeding speed 0.5m/s and detachment angles greater than 6.61deg. S p /S m of aluminum particles in crushed waste refrigerators ranged from 0.08 to 0.51. Separation efficiency increased as the increase of S p /S m . This enlightened us to develop new separator to separate smaller nonferrous metallic particles in e-waste recovery. High feeding speed destroyed separation efficiency. However, greater S p of aluminum particles brought positive impact on separation efficiency. Greater S p could increase critical feeding speed to offer greater throughput of eddy current separation. This paper will guide eddy current separation in production of recovering nonferrous metals from crushed e-waste. Copyright © 2016 Elsevier Ltd. All rights reserved.

Desensitization of chemical activation by auxiliary subunits: convergence of molecular determinants critical for augmenting KCNQ1 potassium channels.

PubMed

Gao, Zhaobing; Xiong, Qiaojie; Sun, Haiyan; Li, Min

2008-08-15

Chemical openers for KCNQ potassium channels are useful probes both for understanding channel gating and for developing therapeutics. The five KCNQ isoforms (KCNQ1 to KCNQ5, or Kv7.1 to Kv7.5) are differentially localized. Therefore, the molecular specificity of chemical openers is an important subject of investigation. Native KCNQ1 normally exists in complex with auxiliary subunits known as KCNE. In cardiac myocytes, the KCNQ1-KCNE1 (IsK or minK) channel is thought to underlie the I(Ks) current, a component critical for membrane repolarization during cardiac action potential. Hence, the molecular and pharmacological differences between KCNQ1 and KCNQ1-KCNE1 channels have been important topics. Zinc pyrithione (ZnPy) is a newly identified KCNQ channel opener, which potently activates KCNQ2, KCNQ4, and KCNQ5. However, the ZnPy effects on cardiac KCNQ1 potassium channels remain largely unknown. Here we show that ZnPy effectively augments the KCNQ1 current, exhibiting an increase in current amplitude, reduction of inactivation, and slowing of both activation and deactivation. Some of these are reminiscent of effects by KCNE1. In addition, neither the heteromultimeric KCNQ1-KCNE1 channels nor native I(Ks) current displayed any sensitivity to ZnPy, indicating that the static occupancy by a KCNE subunit desensitizes the reversible effects by a chemical opener. Site-directed mutagenesis of KCNQ1 reveals that residues critical for the potentiation effects by either ZnPy or KCNE are clustered together in the S6 region overlapping with the critical gating determinants. Thus, the convergence of potentiation effects and molecular determinants critical for both an auxiliary subunit and a chemical opener argue for a mechanistic overlap in causing potentiation.

Response to ``Comment on `Small field behavior of critical current in Y1Ba2Cu3O7 sintered samples' ''

NASA Astrophysics Data System (ADS)

Paternò, G.; Alvani, C.; Casadio, S.; Gambardella, U.; Maritato, L.

1989-05-01

In our response we would like to point out the fitting of the data has done to account for the shift of the maximum magnetic field dependence of the critical current. This shift on the order of 1 Gauss or less is gener ally observed in all our data and is attributable to the residual external field. Since we used a crude junction model, the self-field effects were not included. (AIP)

Effect of the microscopic correlated-pinning landscape on the macroscopic critical current density in YBCO films

NASA Astrophysics Data System (ADS)

Ghigo, G.; Chiodoni, A.; Gerbaldo, R.; Gozzelino, L.; Laviano, F.; Mezzetti, E.; Minetti, B.; Camerlingo, C.

This paper deals with the mechanisms controlling the critical current density vs. field behavior in YBCO films. We base our analysis on a suitable model concerning the existence of a network of intergrain Josephson junctions whose length is modulated by defects. Irradiation with 0.25 GeV Au ions provide a useful tool to check the texture of the sample, in particular to give a gauge length reference to separate “weak” links and high- J c links.

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

DOEpatents

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.

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

DOEpatents

Morris, D.E.

1995-07-04

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. 14 figs.

Critical current and linewidth reduction in spin-torque nano-oscillators by delayed self-injection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khalsa, Guru, E-mail: guru.khalsa@nist.gov; Stiles, M. D.; Grollier, J.

2015-06-15

Based on theoretical models, the dynamics of spin-torque nano-oscillators can be substantially modified by re-injecting the emitted signal to the input of the oscillator after some delay. Numerical simulations for vortex magnetic tunnel junctions show that with reasonable parameters this approach can decrease critical currents as much as 25% and linewidths by a factor of 4. Analytical calculations, which agree well with simulations, demonstrate that these results can be generalized to any kind of spin-torque oscillator.

The development of control and monitoring system on marine current renewable energy Case study: strait of Toyapakeh - Nusa Penida, Bali

NASA Astrophysics Data System (ADS)

Arief, I. S.; Suherman, I. H.; Wardani, A. Y.; Baidowi, A.

2017-05-01

Control and monitoring system is a continuous process of securing the asset in the Marine Current Renewable Energy. A control and monitoring system is existed each critical components which is embedded in Failure Mode Effect Analysis (FMEA) method. As the result, the process in this paper developed through a matrix sensor. The matrix correlated to critical components and monitoring system which supported by sensors to conduct decision-making.

Temperature and field dependence of critical currents in V/sub 3/Ga wire produced by the MJR technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Francavilla, T.L.; Gubser, D.U.; Pande, C.S.

1985-03-01

The temperature dependence of V/sub 3/Ga multifilamentary wire produced by the modified jelly roll technique is reported as a function of applied magnetic field in the range 10K - 14K and 0-13T. Parameters which relate J /SUB c/ to H at 4.2K were found to apply at these temperatures and fields. The form of the temperature dependence of the critical current density is compared with theory.

Longitudinal Proximity Effects in Superconducting Transition-Edge Sensors

NASA Technical Reports Server (NTRS)

Sadlier, John E.; Smith, Stephen J.; Bandler, Simon R.; Chervenak, James A.; Clem, John R.

2009-01-01

We have found experimentally that the critical current of a square thin-film superconducting transition-edge sensor (TES) depends exponentially upon the side length L and the square root of the temperature T, a behavior that has a natural theoretical explanation in terms of longitudinal proximity effects if the TES is regarded as a weak link between superconducting leads. As a consequence, the effective transition temperature T(sub c) of the TES is current-dependent and at fixed current scales as 1/L(sup 2). We also have found that the critical current can show clear Fraunhofer-like oscillations in an applied magnetic field, similar to those found in Josephson junctions. We have observed the longitudinal proximity effect in these devices over extraordinarily long lengths up to 290 micrometers, 1450 times the mean-free path.

Longitudinal Proximity Effects in Superconducting Transition-Edge Sensors

NASA Technical Reports Server (NTRS)

Sadleir, John E.; Smith, Stephen J.; Bandler, Simon R.; Chervenak, James A.; Clem, John R.

2010-01-01

We have found experimentally that the critical current of a square thin-film superconducting transition-edge sensor (TES) depends exponentially upon the side length L and the square root of the temperature T, a behavior that has a natural theoretical explanation in terms of longitudinal proximity effects if the TES is regarded as a weak link between superconducting leads. As a consequence, the effective transition temperature T(sub c) of the TES is current-dependent and at fixed current scales as 1/L(sup 2). We also have found that the critical current can show clear Fraunhofer-like oscillations in an applied magnetic field, similar to those found in Josephson junctions. We have observed the longitudinal proximity effect in these devices over extraordinarily long lengths up to 290 micrometers, 1450 times the mean-free path.

Stock markets and criticality in the current economic crisis

NASA Astrophysics Data System (ADS)

da Silva, Roberto; Zembrzuski, Marcelo; Correa, Fabio C.; Lamb, Luis C.

2010-12-01

We show that the current economic crisis has led the market to exhibit a non-critical behavior. We do so by analyzing the quantitative parameters of time series from the main assets of the Brazilian Stock Market BOVESPA. By monitoring global persistence we show a deviation of power law behavior during the crisis in a strong analogy with spin systems (from where this concept was originally conceived). Such behavior is corroborated by an emergent heavy tail of absolute return distribution and also by the magnitude autocorrelation exponent. Comparisons with universal exponents obtained in the international stock markets are also performed. This suggests how a thorough analysis of suitable exponents can bring a possible way of forecasting market crises characterized by non-criticality.

Critical thinking as an educational outcome: an evaluation of current tools of measurement.

PubMed

Adams, M H; Whitlow, J F; Stover, L M; Johnson, K W

1996-01-01

Critical thinking, an outcome criterion of the National League for Nursing and the Council of Baccalaureate and Higher Degree Programs, is an abstract skill difficult to measure. The authors provide a comprehensive review of four instruments designed to measure critical thinking and summarize research in which the tools were used. Analysis of this information will empower nursing faculty members to select a critical-thinking instrument that is individualized to the needs of their respective nursing programs.

Advanced electrical current measurements of microdischarges: evidence of sub-critical pulses and ion currents in barrier discharge in air

NASA Astrophysics Data System (ADS)

Synek, Petr; Zemánek, Miroslav; Kudrle, Vít; Hoder, Tomáš

2018-04-01

Electrical current measurements in corona or barrier microdischarges are a challenge as they require both high temporal resolution and a large dynamic range of the current probe used. In this article, we apply a simple self-assembled current probe and compare it to commercial ones. An analysis in the time and frequency domain is carried out. Moreover, an improved methodology is presented, enabling both temporal resolution in sub-nanosecond times and current sensitivity in the order of tens of micro-amperes. Combining this methodology with a high-tech oscilloscope and self-developed software, a unique statistical analysis of currents in volume barrier discharge driven in atmospheric-pressure air is made for over 80 consecutive periods of a 15 kHz applied voltage. We reveal the presence of repetitive sub-critical current pulses and conclude that these can be identified with the discharging of surface charge microdomains. Moreover, extremely low, long-lasting microsecond currents were detected which are caused by ion flow, and are analysed in detail. The statistical behaviour presented gives deeper insight into the discharge physics of these usually undetectable current signals.

Advantageous grain boundaries in iron pnictide superconductors

PubMed Central

Katase, Takayoshi; Ishimaru, Yoshihiro; Tsukamoto, Akira; Hiramatsu, Hidenori; Kamiya, Toshio; Tanabe, Keiichi; Hosono, Hideo

2011-01-01

High critical temperature superconductors have zero power consumption and could be used to produce ideal electric power lines. The principal obstacle in fabricating superconducting wires and tapes is grain boundaries—the misalignment of crystalline orientations at grain boundaries, which is unavoidable for polycrystals, largely deteriorates critical current density. Here we report that high critical temperature iron pnictide superconductors have advantages over cuprates with respect to these grain boundary issues. The transport properties through well-defined bicrystal grain boundary junctions with various misorientation angles (θGB) were systematically investigated for cobalt-doped BaFe2As2 (BaFe2As2:Co) epitaxial films fabricated on bicrystal substrates. The critical current density through bicrystal grain boundary (JcBGB) remained high (>1 MA cm−2) and nearly constant up to a critical angle θc of ∼9°, which is substantially larger than the θc of ∼5° for YBa2Cu3O7–δ. Even at θGB>θc, the decay of JcBGB was much slower than that of YBa2Cu3O7–δ. PMID:21811238

Pulsed Eddy Current Sensing for Critical Pipe Condition Assessment.

PubMed

Ulapane, Nalika; Alempijevic, Alen; Vidal Calleja, Teresa; Valls Miro, Jaime

2017-09-26

Pulsed Eddy Current (PEC) sensing is used for Non-Destructive Evaluation (NDE) of the structural integrity of metallic structures in the aircraft, railway, oil and gas sectors. Urban water utilities also have extensive large ferromagnetic structures in the form of critical pressure pipe systems made of grey cast iron, ductile cast iron and mild steel. The associated material properties render NDE of these pipes by means of electromagnetic sensing a necessity. In recent years PEC sensing has established itself as a state-of-the-art NDE technique in the critical water pipe sector. This paper presents advancements to PEC inspection in view of the specific information demanded from water utilities along with the challenges encountered in this sector. Operating principles of the sensor architecture suitable for application on critical pipes are presented with the associated sensor design and calibration strategy. A Gaussian process-based approach is applied to model a functional relationship between a PEC signal feature and critical pipe wall thickness. A case study demonstrates the sensor's behaviour on a grey cast iron pipe and discusses the implications of the observed results and challenges relating to this application.

Doubling of the Critical Current Density of 2G-YBCO Coated Conductors through proton irradiation

NASA Astrophysics Data System (ADS)

Welp, Ulrich; Jia, Ying; Kwok, Wai-Kwong; Rupich, Marty; Fleshler, Steven; Kayani, Asfghar

2013-03-01

We report on magnetization and transport measurements of the critical current density of commercial 2G YBCO coated conductors before and after proton irradiation. The samples were irradiated along the c-axis with 4 MeV protons to a fluence of 1.5x1016 p/cm2. We find that at temperatures below 50 K, proton irradiation increases Jc by a factor of 2 in low fields and increases up to 2.5 in fields of 7 T. At 77 K, proton irradiation is less effective in enhancing the critical current. Doubling of Jc in fields of several Tesla and at temperatures below 50 K will be highly beneficial for applications of coated conductors in rotating machinery, generators and magnet coils. - Work supported by the US DoE-BES funded Energy Frontier Research Center (YJ), and by Department of Energy, Office of Science, Office of Basic Energy Sciences (UW, WKK), under Contract No. DE-AC02-06CH11357.

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

NASA Technical Reports Server (NTRS)

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.

Numerical and Experimental Investigation of the Electromechanical Behavior of REBCO Tapes

NASA Astrophysics Data System (ADS)

Allen, N. C.; Chiesa, L.; Takayasu, M.

2015-12-01

To fully characterize the electromechanical behavior of a Twisted Stacked-Tape Cable (TSTC) it is important to understand the performance of the individual REBCO tapes under various loading conditions. Numerical modeling and experimentation have been used to investigate the electromechanical characteristics of two commercially available REBCO tapes (SuperPower and SuNAM). Tension and combined tension-torsion experiments on single tapes have been continued, from prior preliminary studies, to characterize their critical current behavior and mechanical strength. Additionally, structural finite element analysis was performed on single tapes under tension and combined tension-torsion to investigate the strain dependence of the critical current. The numerical results were compared to the experimental findings for validation. The SuNAM experimental data matched the numerical model very well while the SuperPower tape experienced degradation at lower stress and strain than predicted in the model. The Superpower tape also displayed greater variability in critical current between different samples as compared with the SuNAM tape.

Microstructure and critical current density in MgB2 bulk made of 4.5 wt% carbon-coated boron

NASA Astrophysics Data System (ADS)

Higuchi, M.; Muralidhar, M.; Jirsa, M.; Murakami, M.

2017-07-01

Superconducting performance and its uniformity was studied in the single-step sintered MgB2 bulk prepared with 4.5 wt% of carbon in the carbon-encapsulated boron. The 20 mm in diameter MgB2 pellet was cut into several pieces from bottom to top and the microstructure, superconducting transition temperature (Tc onset), and critical current density at 20 K were studied. DC magnetization measurements showed a sharp superconducting transition with onset Tc at around 35.5 K in all positions. SEM analysis indicated a dispersion of grains between 200 and 300 nm in size, as the main pinning medium in this MgB2 superconductors. The critical current density at 20 K was quite uniform, around 330 kA/cm2 and 200 kA/cm2 at self-field and 1 T, respectively, for all measured positions. The results indicate that the carbon-encapsulated boron is very promising for production of high quality bulk MgB2 material for various industrial applications.

Eating psychopathology amongst athletes: links to current attachment styles.

PubMed

Shanmugam, Vaithehy; Jowett, Sophia; Meyer, Caroline

2012-01-01

The aims of the study were two-fold; first to determine the associations between current attachment styles, and eating psychopathology amongst athletes, and second to simultaneously assess the mediating effects of self-esteem, perfectionism, and depression in this association. Four hundred and eleven British athletes completed self-report instruments pertaining to eating psychopathology, attachment styles, self-esteem, depression, and perfectionism. Athletes who scored highly on both avoidant and anxious attachment styles, reported elevated eating psychopathology scores. However, such associations were indirect and mediated via athletes' levels of self-esteem, self-critical perfectionism, and depression, with self-esteem and depression identified as more salient mediators than self-critical perfectionism. The current findings provide evidence to suggest that insecure attachment styles influence athletes' eating psychopathology via their impact on self-esteem, depression, and self-critical perfectionism. Moreover, self-esteem and depression may play more significant role in transferring the impact of insecure attachment styles on elevated eating psychopathology. Copyright © 2011 Elsevier Ltd. All rights reserved.

Advanced development and calibration of the network robustness index to identify critical road network links.

DOT National Transportation Integrated Search

2010-05-31

In this research project, transportation flexibility and reliability concepts are extended and applied : to a new method for identifying the most critical links in a road network. Current transportation : management practices typically utilize locali...

High temperature superconductor materials and applications

NASA Technical Reports Server (NTRS)

Doane, George B., III.; Banks, Curtis; Golben, John

1990-01-01

Research on processing methods leading to a significant enhancement in the critical current densities (Jc) and the critical temperature (Tc) of high temperature superconducting in thin bulk and thin film forms. The fabrication of important devices for NASA unique applications (sensors) is investigated.

White Men's Racial Others

ERIC Educational Resources Information Center

Lensmire, Timothy J.

2014-01-01

Background/Context: Increasingly, researchers and educators have argued that alternative conceptions of Whiteness and White racial identity are needed because current conceptions have undermined, rather than strengthened, our critical pedagogies with White people. Grounded in critical Whiteness studies, and drawing especially on the writings of…

Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

DTIC Science & Technology

2013-01-02

41 The National Academy of Sciences Study and Its Critics ...reliable and safe. So he has not ruled out testing in the future, but there are no plans to do so.”6 Critics expressed concern about the...nuclear weapons testing.”7 Another critic felt that increased funding for test readiness would in effect give prior approval for testing. In July 2002 a

The Cultures of Contemporary Instructional Design Scholarship, Part Two: Developments Based on Constructivist and Critical Theory Foundations

ERIC Educational Resources Information Center

Willis, Jerry

2011-01-01

This article is the second in a series (see Willis, 2011) that looks at the current status of instructional design scholarship and theory. In this concluding article, the focus is on two cultures of ID work, one based on constructivist and interpretivist theory and the other based on critical theory and critical pedagogy. There are distinct…

Critical Race Theory in Education, Marxism and Abstract Racial Domination

ERIC Educational Resources Information Center

Cole, Mike

2012-01-01

In the context of the ongoing debate between critical race theory (CRT) and Marxism, I begin in this paper by examining the origins of CRT in Critical Legal Studies (CLS) in the United States. I go on to describe CRT's entry into education, first in that country, and then in the United Kingdom. I move on to a discussion of current debates between…

Giving Voices to Mexican Immigrant Parents: A Mixed Methods Study of Perceptions on the Transition to School

ERIC Educational Resources Information Center

Beasley, Jennifer M.

2013-01-01

The transition to formal schooling is thought of as a critical educational experience for all children and their families. This transition may be especially critical for those in the largest immigrant group in the United States, Mexican families and their children. Using Critical Race Theory, the aim of the current study was to give Mexican…

The Evolution of Military Trauma and Critical Care Medicine: Applications for Civilian Medical Care Systems

DTIC Science & Technology

2008-01-01

evidence - based medicine . Like great leaders in medicine such as Ibn Sina, war and conflict have also been credited with advances in medical and surgical therapy throughout the centuries. Like in previous conflicts, many authors note that innovations in trauma and critical care evolving from the current global war on terrorism may significantly impact civilian trauma care, critical

Plantar hyperhidrosis: A review of current management.

PubMed

Singh, Sanjay; Kaur, Simranjit; Wilson, Paul

2016-11-01

To critically appraise current literature regarding the management of plantar hyperhidrosis in the form of a structured review. A literature search was conducted using various databases and search criteria. The literature reports the use of conservative, medical and surgical treatment modalities for the management of plantar hyperhidrosis. However, long-term follow-up data are rare and some treatment modalities currently available are not fully understood. There is a considerable dearth in the literature on the management of plantar hyperhidrosis. Further study in larger populations with longer follow-up times is critical to access the long-term effects of treatment. Nonetheless, iontophoresis, botulinum toxin injection and lumbar sympathectomy are promising treatment modalities for this disorder.

Macroscopic Quantum Tunneling in Superconducting Junctions of β-Ag2Se Topological Insulator Nanowire.

PubMed

Kim, Jihwan; Kim, Bum-Kyu; Kim, Hong-Seok; Hwang, Ahreum; Kim, Bongsoo; Doh, Yong-Joo

2017-11-08

We report on the fabrication and electrical transport properties of superconducting junctions made of β-Ag 2 Se topological insulator (TI) nanowires in contact with Al superconducting electrodes. The temperature dependence of the critical current indicates that the superconducting junction belongs to a short and diffusive junction regime. As a characteristic feature of the narrow junction, the critical current decreases monotonously with increasing magnetic field. The stochastic distribution of the switching current exhibits the macroscopic quantum tunneling behavior, which is robust up to T = 0.8 K. Our observations indicate that the TI nanowire-based Josephson junctions can be a promising building block for the development of nanohybrid superconducting quantum bits.

YBCO microbolometer operating below Tc - A modelization based on critical current-temperature dependence

NASA Astrophysics Data System (ADS)

Robbes, D.; Langlois, P.; Dolabdjian, C.; Bloyet, D.; Hamet, J. F.; Murray, H.

1993-03-01

Using careful measurements of the I-V curve of a YBCO thin-film microbridge under light irradiation at 780 nm and temperature close to 77 K, it is shown that the critical current versus temperature dependence is a good thermometer for estimating bolometric effects in the film. A novel dynamic voltage bias is introduced which directly gives the device current responsitivity and greatly reduces risks of thermal runaway. Detectivity is very low but it is predicted that a noise equivalent temperature of less than 10 exp -7 K/sq rt Hz would be achievable in a wide temperature range (10-80 K), which is an improvement over thermometry at the resistive transition.

One-dimensional pinning behavior in Co-doped BaFe2As2 thin films

NASA Astrophysics Data System (ADS)

Mishev, V.; Seeböck, W.; Eisterer, M.; Iida, K.; Kurth, F.; Hänisch, J.; Reich, E.; Holzapfel, B.

2013-12-01

Angle-resolved transport measurements revealed that planar defects dominate flux pinning in the investigated Co-doped BaFe2As2 thin film. For any given field and temperature, the critical current depends only on the angle between the crystallographic c-axis and the applied magnetic field but not on the angle between the current and the field. The critical current is therefore limited only by the in-plane component of the Lorentz force but independent of the out-of-plane component, which is entirely balanced by the pinning force exerted by the planar defects. This one-dimensional pinning behavior shows similarities and differences to intrinsic pinning in layered superconductors.

Back-Hopping in Spin-Transfer-Torque Devices: Possible Origin and Countermeasures

NASA Astrophysics Data System (ADS)

Abert, Claas; Sepehri-Amin, Hossein; Bruckner, Florian; Vogler, Christoph; Hayashi, Masamitsu; Suess, Dieter

2018-05-01

The effect of undesirable high-frequency free-layer switching in magnetic multilayer systems, referred to as back-hopping, is investigated by means of the spin-diffusion model. A possible origin of the back-hopping effect is found to be the destabilization of the pinned layer, which leads to the perpetual switching of both layers. While the presented mechanism is not claimed to be the only possible reason for back-hopping, we show that it is a fundamental effect that will occur in any spin-transfer-torque device when exceeding a critical current. The influence of different material parameters on the critical switching currents for the free and pinned layer is obtained by micromagnetic simulations. The spin-diffusion model enables an accurate description of the torque on both layers, depending on various material parameters. It is found that the choice of a free-layer material with low polarization β and saturation magnetization Ms and a pinned-layer material with high β and Ms leads to a low free-layer critical current and a high pinned-layer critical current and hence reduces the likelihood of back-hopping. While back-hopping has been observed in various types of devices, there are only a few experiments that exhibit this effect in perpendicularly magnetized systems. However, our simulations suggest that the described effect will also gain importance in perpendicular systems due to the loss of pinned-layer anisotropy for decreasing device sizes.

Comparison of free flux flow in two single crystals of V3Si with slightly different pinning strengths

NASA Astrophysics Data System (ADS)

Gafarov, Ozarfar; Gapud, Albert A.; Moraes, Sunhee; Thompson, James R.; Christen, David K.; Reyes, Arneil P.

2011-03-01

Results of recent measurements on two very clean, single-crystal samples of the A15 superconductor V3 Si are presented. Magnetization and transport data confirm the ``clean'' quality of both samples, as manifested by: (i) high residual resistivity ratio, (ii) low critical current densities, and (iii) a ``peak'' effect in the field dependence of critical current. The (H,T) phase line for this peak effect is shifted in the slightly ``dirtier'' sample, which also has higher critical current density Jc (H). High-current Lorentz forces are applied on mixed-state vortices in order to induce the highly ordered free flux flow (FFF) phase, using the same methods as in previous work. A traditional model by Bardeen and Stephen (BS) predicts a simple field dependence of flux flow resistivity ρf (H), presuming a field-independent flux core size. A model by Kogan and Zelezhina (KZ) takes core size into account, and predicts a deviation from BS. In this study, ρf (H) is confirmed to be consistent with predictions of KZ, as will be discussed. Funded by Research Corporation and the National Science Foundation.

Free flux flow in two single crystals of V3Si with differing pinning strengths

NASA Astrophysics Data System (ADS)

Gafarov, O.; Gapud, A. A.; Moraes, S.; Thompson, J. R.; Christen, D. K.; Reyes, A. P.

2011-10-01

Results of measurements on two very clean, single-crystal samples of the A15 superconductor V3Si are presented. Magnetization and transport data have confirmed the ``clean'' quality of both samples, as manifested by: (i) high residual electrical resistivity ratio, (ii) very low critical current densities Jc, and (iii) a ``peak'' effect in the field dependence of critical current. The (H,T) phase line for this peak effect is shifted down for the slightly ``dirtier'' sample, which consequently also has higher critical current density Jc(H). Large Lorentz forces are applied on mixed-state vortices via large currents, in order to induce the highly ordered free flux flow (FFF) phase, using experimental methods developed previously. The traditional model by Bardeen and Stephen (BS) predicts a simple field dependence of flux flow resistivity ρf(H) ˜ H/Hc2, presuming a field-independent flux core size. A model by Kogan and Zelezhina (KZ) takes into account the effects of magnetic field on core size, and predict a clear deviation from the linear BS dependence. In this study, ρf(H) is confirmed to be consistent with predictions of KZ.

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

NASA Astrophysics Data System (ADS)

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.

Wind-induced vibration of stay cables : brief

DOT National Transportation Integrated Search

2005-02-01

The objectives of this project were to: : Identify gaps in current knowledge base : Conduct analytical and experimental research in critical areas : Study performance of existing cable-stayed bridges : Study current mitigation methods...

Dominant Discourses in Curriculum

ERIC Educational Resources Information Center

Miller, Elizabeth

2012-01-01

In the following paper, the author draws upon the works of critical theorists and critical curriculum scholars to investigate the intersection of the social and political realms with contemporary educational and curricular trends. This paper specifically explores connections between current curriculum trends with neutrality, social reproduction,…

Selenium and glutamine supplements: where are we heading? A critical care perspective.

PubMed

Andrews, Peter J D

2010-03-01

There is considerable interest in glutamine and selenium in critical care as both offer the potential to enhance host defences, through different but complimentary mechanisms and may reduce subsequent infections and mortality. The SIGNET trial (randomized controlled factorial trial) is the largest, critical care study of both supplements. The data have been presented publicly, but the data are not published or available for review and will therefore not be discussed fully in this update. In the present review I will explore the recently available (past 1-2 years) published literature. The current literature demonstrates that there are currently insufficient data to enable confident recommendations on the optimal route, timing, duration and dosage of each of these nutritional supplements. The pending results of SIGNET, the largest critical care trial of parenteral nutrition supplemented by glutamine and or selenium promises to clarify some of the current ambiguities and inform future practice. To be able to confidently establish or refute the hypothesis that either glutamine or selenium alone or in combination improves outcome in critical care requires a well designed prospective randomized controlled trial. To design such a trial we require the optimal dose and duration of the nutritional supplement (balancing efficacy and toxicity, ease of administration and cost) and then conduct an adequately powered trial. Such a trial is still lacking for these two agents. There are some supportive data for selenium but the case is less strong for parenteral glutamine and weakest for enteral glutamine.

The optimal blood glucose level for critically ill adult patients.

PubMed

Lv, Shaoning; Ross, Paul; Tori, Kathleen

2017-09-01

Glycaemic control is recognized as one of the important aspects in managing critically ill patients. Both hyperglycaemia and hypoglycaemia independently increase the risk of patient mortality. Hence, the identification of optimal glycaemic control is of paramount importance in the management of critically ill patients. The aim of this literature review is to examine the current status of glycaemic control in critically ill adult patients. This literature review will focus on randomized controlled trials comparing intensive insulin therapy to conventional insulin therapy, with an objective to identify optimal blood glucose level targets for critically ill adult patients. A literature review was conducted to identify large randomized controlled trials for the optimal targeted blood glucose level for critically ill adult patients published since 2000. A total of eight studies fulfilled the selection criteria of this review. With current human and technology resources, the results of the studies support commencing glycaemic control once the blood glucose level of critically ill patients reaches 10 mmol/L and maintaining this level between 8 mmol/L and 10 mmol/L. This literature review provides a recommendation for targeting the optimal blood glucose level for critically ill patients within moderate blood glucose level target range (8-10 mmol/L). The need for uniformed glucometrics for unbiased reporting and further research for optimal blood glucose target is required, especially in light of new technological advancements in closed-loop insulin delivery and monitoring devices. This literature review has revealed a need to call for consensus in the measurement and reporting of glycaemic control using standardized glucometrics. © 2017 British Association of Critical Care Nurses.

Critical education in resource and environmental management: Learning and empowerment for a sustainable future

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diduck, A.

1999-10-01

Changing rom current patterns of resource use to a sustainable and equitable economy is a complex and intractable problem. This paper suggests that critical education may form part of the solution. Critical environmental assessment (EA) education, the model explored in this paper, offers a tool for resource and environmental managers to use in managing public involvement processes. This model challenges current patterns of resource use and addresses criticisms of public involvement processes. Critical EA education, involving both cognitive development and personal empowerment, focuses on critical intelligence, problem solving and social action. The concept is offered as a means to facilitatemore » and improve public involvement and, thereby, empower local communities to take greater control of resource use decisions affecting their lives. Positive implications of critical EA education for change, complexity, uncertainty and conflict, which are four enduring themes in resource and environmental management, are discussed in the paper. The implications include: cognitive development and personal empowerment at the level of local resource communities; simplification of the often complex discourse encountered in resource management; reduction in feelings of powerlessness often experienced by members of the public in environmental assessment scenarios; a reduction of ignorance and indeterminacy regarding resource management issues; conflict resolution at the cognitive level; and, clarification of the opposing values, interests or actions at the heart of a conflict.« less

Critical consciousness, racial and gender discrimination, and HIV disease markers in African American women with HIV.

PubMed

Kelso, Gwendolyn A; Cohen, Mardge H; Weber, Kathleen M; Dale, Sannisha K; Cruise, Ruth C; Brody, Leslie R

2014-07-01

Critical consciousness, the awareness of social oppression, is important to investigate as a buffer against HIV disease progression in HIV-infected African American women in the context of experiences with discrimination. Critical consciousness comprises several dimensions, including social group identification, discontent with distribution of social power, rejection of social system legitimacy, and a collective action orientation. The current study investigated self-reported critical consciousness as a moderator of perceived gender and racial discrimination on HIV viral load and CD4+ cell count in 67 African American HIV-infected women. Higher critical consciousness was found to be related to higher likelihood of having CD4+ counts over 350 and lower likelihood of detectable viral load when perceived racial discrimination was high, as revealed by multiple logistic regressions that controlled for highly active antiretroviral therapy (HAART) adherence. Multiple linear regressions showed that at higher levels of perceived gender and racial discrimination, women endorsing high critical consciousness had a larger positive difference between nadir CD4+ (lowest pre-HAART) and current CD4+ count than women endorsing low critical consciousness. These findings suggest that raising awareness of social oppression to promote joining with others to enact social change may be an important intervention strategy to improve HIV outcomes in African American HIV-infected women who report experiencing high levels of gender and racial discrimination.

Critical Consciousness, Racial and Gender Discrimination, and HIV Disease Markers in African American Women with HIV

PubMed Central

Kelso, Gwendolyn A.; Cohen, Mardge H.; Weber, Kathleen M.; Dale, Sannisha K.; Cruise, Ruth C.; Brody, Leslie R.

2014-01-01

Critical consciousness, the awareness of social oppression, is important to investigate as a buffer against HIV disease progression in HIV-infected African American women in the context of experiences with discrimination. Critical consciousness comprises several dimensions, including social group identification, discontent with distribution of social power, rejection of social system legitimacy, and a collective action orientation. The current study investigated self-reported critical consciousness as a moderator of perceived gender and racial discrimination on HIV viral load and CD4+ cell count in 67 African American HIV-infected women. Higher critical consciousness was found to be related to higher likelihood of having CD4+ counts over 350 and lower likelihood of detectable viral load when perceived racial discrimination was high, as revealed by multiple logistic regressions that controlled for highly active antiretroviral therapy (HAART) adherence. Multiple linear regressions showed that at higher levels of perceived gender and racial discrimination, women endorsing high critical consciousness had a larger positive difference between nadir CD4+ (lowest pre-HAART) and current CD4+ count than women endorsing low critical consciousness. These findings suggest that raising awareness of social oppression to promote joining with others to enact social change may be an important intervention strategy to improve HIV outcomes in African American HIV-infected women who report experiencing high levels of gender and racial discrimination. PMID:24077930

Multiscale modeling of localized resistive heating in nanocrystalline metals subjected to electropulsing

NASA Astrophysics Data System (ADS)

Zhao, Jingyi; Wang, G.-X.; Dong, Yalin; Ye, Chang

2017-08-01

Many electrically assisted processes have been reported to induce changes in microstructure and metal plasticity. To understand the physics-based mechanisms behind these interesting phenomena, however, requires an understanding of the interaction between the electric current and heterogeneous microstructure. In this work, multiscale modeling of the electric current flow in a nanocrystalline material is reported. The cellular automata method was used to track the nanoscale grain boundaries in the matrix. Maxwell's electromagnetic equations were solved to obtain the electrical potential distribution at the macro scale. Kirchhoff's circuit equation was solved to obtain the electric current flow at the micro/nano scale. The electric current distribution at two representative locations was investigated. A significant electric current concentration was observed near the grain boundaries, particularly near the triple junctions. This higher localized electric current leads to localized resistive heating near the grain boundaries. The electric current distribution could be used to obtain critical information such as localized resistive heating rate and extra system free energy, which are critical for explaining many interesting phenomena, including microstructure evolution and plasticity enhancement in many electrically assisted processes.

Telemedicine in Critical Care

PubMed Central

Murias, Gastón; Sales, Bernat; Garcia-Esquirol, Oscar; Blanch, Lluis

2009-01-01

Critical care medicine is the specialty that cares for patients with acute life-threatening illnesses where intensivists look after all aspects of patient care. Nevertheless, shortage of physicians and nurses, the relationship between high costs and economic restrictions, and the fact that critical care knowledge is only available at big hospitals puts the system on the edge. In this scenario, telemedicine might provide solutions to improve availability of critical care knowledge where the patient is located, improve relationship between attendants in different institutions and education material for future specialist training. Current information technologies and networking capabilities should be exploited to improve intensivist coverage, advanced alarm systems and to have large critical care databases of critical care signals. PMID:19452034

Threshold fluctuations in a superconducting current-carrying bridge

NASA Astrophysics Data System (ADS)

Marychev, P. M.; Vodolazov, D. Yu

2017-07-01

We calculate the energy of threshold fluctuation δ {F}{{thr}} which triggers the transition of a superconducting current-carrying bridge to the resistive state. We show that the dependence δ {F}{{thr}}{(I)\\propto {I}{{dep}}{\\hslash }(1-I/{I}{{dep}})}5/4/e, found by Langer and Ambegaokar for a long bridge with length L\\gg ξ , holds far below the critical temperature in both dirty and clean limits (here I dep is the depairing current of the bridge and ξ is a coherence length). We also find that even a ‘weak’ local defect (leading to a small suppression of the critical current of the bridge {I}{{c}}≲ {I}{{dep}}) provides δ {F}{{thr}}\\propto {I}{{c}}{\\hslash }{(1-I/{I}{{c}})}3/2/e, typical for a short bridge with L\\ll ξ or a Josephson junction.

Mechanisms of weak thickness dependence of the critical current density in strong-pinning ex situ metal organic-deposition-route YBa2Cu3O7-x coated conductors

NASA Astrophysics Data System (ADS)

Kim, S. I.; Gurevich, A.; Song, X.; Li, X.; Zhang, W.; Kodenkandath, T.; Rupich, M. W.; Holesinger, T. G.; Larbalestier, D. C.

2006-09-01

We report on the thickness dependence of the superconducting characteristics including critical current Ic, critical current density Jc, transition temperature Tc, irreversibility field Hirr, bulk pinning force plot Fp(H), and normal state resistivity curve ρ(T) measured after successive ion milling of ~1 µm thick high-Ic YBa2Cu3O7-x films made by an ex situ metal-organic deposition process on Ni-W rolling-assisted biaxially textured substrates (RABiTSTM). In contrast to many recent data, mostly on in situ pulsed laser deposition (PLD) films, which show strong depression of Jc with increasing film thickness t, our films exhibit only a weak dependence of Jc on t. The two better textured samples had full cross-section average Jc,avg (77 K, 0 T) ~4 MA cm-2 near the buffer layer interface and ~3 MA cm-2 at full thickness, despite significant current blocking due to ~30% porosity in the film. Taking account of the thickness dependence of the porosity, we estimate that the local, vortex-pinning current density is essentially independent of thickness, while accounting for the additional current-blocking effects of grain boundaries leads to local, vortex-pinning Jc values well above 5 MA cm-2. Such high local Jc values are produced by strong three-dimensional vortex pinning which subdivides vortex lines into weakly coupled segments much shorter than the film thickness.

"Ideal" tearing and the transition to fast reconnection in the weakly collisional MHD and EMHD regimes

NASA Astrophysics Data System (ADS)

Del Sarto, Daniele; Pucci, Fulvia; Tenerani, Anna; Velli, Marco

2016-03-01

This paper discusses the transition to fast growth of the tearing instability in thin current sheets in the collisionless limit where electron inertia drives the reconnection process. It has been previously suggested that in resistive MHD there is a natural maximum aspect ratio (ratio of sheet length and breadth to thickness) which may be reached for current sheets with a macroscopic length L, the limit being provided by the fact that the tearing mode growth time becomes of the same order as the Alfvén time calculated on the macroscopic scale. For current sheets with a smaller aspect ratio than critical the normalized growth rate tends to zero with increasing Lundquist number S, while for current sheets with an aspect ratio greater than critical the growth rate diverges with S. Here we carry out a similar analysis but with electron inertia as the term violating magnetic flux conservation: previously found scalings of critical current sheet aspect ratios with the Lundquist number are generalized to include the dependence on the ratio de2/L2, where de is the electron skin depth, and it is shown that there are limiting scalings which, as in the resistive case, result in reconnecting modes growing on ideal time scales. Finite Larmor radius effects are then included, and the rescaling argument at the basis of "ideal" reconnection is proposed to explain secondary fast reconnection regimes naturally appearing in numerical simulations of current sheet evolution.

Individual and organizational predictors of depression in general practitioners.

PubMed

Firth-Cozens, J

1998-10-01

High levels of stress and depression are seen in both general practitioners (GPs) and hospital doctors, and this has implications for patient care. It is therefore important to discover the individual and organizational causes of elevated symptoms so they can be tackled. To discover the relative importance of individual characteristics measured 10 years earlier compared with current organizational stressors in predicting depression in GPs. Longitudinal questionnaire study, using data from those of the original cohort of 318 medical students who are now GPs (n = 131), considering perceptions of current stressors and comparing through regression analyses the relative strength of early personality and mood with current organizational factors of sleep, hours worked, and practice size in predicting current depression levels. There were 22 (17%) stressors scoring above threshold for depression. Relationships with senior doctors and patients are the main reported stressors, followed by making mistakes and conflict of career with personal life. The predictors of symptom levels varied for men and women. In men, depression and self-criticism as students, and current sleep levels; and in women, sibling rivalry and current alcohol use, were the main predictors: in men, 27% of the variance was accounted for by early dispositional factors alone compared with 14% in women. A model is suggested linking sleep loss with workplace stressors, self-critical cognitions, and depression. Interventions can be made throughout training, targeting self-criticism and recognizing early depression, while later addressing the organizational stressors, particularly work relationships and sleep patterns.

Venous thromboembolism prophylaxis in the critically ill: a point prevalence survey of current practice in Australian and New Zealand intensive care units.

PubMed

Robertson, Megan S; Nichol, Alistair D; Higgins, Alisa M; Bailey, Michael J; Presneill, Jeffrey J; Cooper, D James; Webb, Steven A; McArthur, Colin; MacIsaac, Christopher M

2010-03-01

Critically ill patients are at high risk of morbidity and mortality caused by venous thromboembolism (VTE). In addition to premorbid predisposing conditions, critically ill patients may be exposed to prolonged immobility, invasive intravascular catheters and frequent operative procedures, and further may have contraindications to pharmaceutical prophylactic measures designed to attenuate VTE risk. There are limited data describing current VTE prophylaxis regimens in Australia and New Zealand. To document current Australian and New Zealand management of VTE prophylaxis in a large mixed cohort of critically ill patients. Prospective, multicentre point prevalence survey endorsed by the Australian and New Zealand Intensive Care Society Clinical Trials Group (ANZICS CTG). 30 public hospital ICUs in Australia and New Zealand surveyed on Wednesday 9 May 2007. For all patients in each ICU on the study day, demographic data, admission diagnosis and information on VTE prophylaxis were prospectively collected. 502 patients were included in the survey, and 431 of these (86%) received VTE prophylaxis. Of these, 64% (276/431) received pharmacological prophylaxis and 80% (345/431) received mechanical prophylaxis, with 44% (190/431) receiving both. Of those receiving pharmacological prophylaxis, unfractionated heparin was used in 74%, and enoxaparin (low molecular weight heparin) in 23%. Contraindications to pharmacological prophylaxis were reported in 122 patients. Overall, pharmacological prophylaxis was administered to 87% of potentially suitable patients. We observed a high prevalence of VTE prophylaxis, with many critically ill patients receiving two or more modalities of prophylaxis. These results show that the potential risk of VTE in critically ill patients is recognised in Australia and New Zealand, and strategies to mitigate this serious complication are widely implemented.

Raw material ‘criticality’—sense or nonsense?

NASA Astrophysics Data System (ADS)

Frenzel, M.; Kullik, J.; Reuter, M. A.; Gutzmer, J.

2017-03-01

The past decade has seen a resurgence of interest in the supply security of mineral raw materials. A key to the current debate is the concept of ‘criticality’. The present article reviews the criticality concept, as well as the methodologies used in its assessment, including a critical evaluation of their validity in view of classical risk theory. Furthermore, it discusses a number of risks present in global raw materials markets that are not captured by most criticality assessments. Proposed measures for the alleviation of these risks are also presented. We find that current assessments of raw material criticality are fundamentally flawed in several ways. This is mostly due to a lack of adherence to risk theory, and highly limits their applicability. Many of the raw materials generally identified as critical are probably not critical. Still, the flaws of current assessments do not mean that the general issue of supply security can simply be ignored. Rather, it implies that new assessments are required. While the basic theoretical framework for such assessments is outlined in this review, detailed method development will require a major collaborative effort between different disciplines along the raw materials value chain. In the opinion of the authors, the greatest longer-term challenge in the raw materials sector is to stop, or counteract the effects of, the escalation of unit energy costs of production. This issue is particularly pressing due to its close link with the renewable energy transition, requiring more metal and mineral raw materials per unit energy produced. The solution to this problem will require coordinated policy action, as well as the collaboration of scientists from many different fields—with physics, as well as the materials and earth sciences in the lead.

Pharmacist independent prescribing in critical care: results of a national questionnaire to establish the 2014 UK position.

PubMed

Bourne, Richard S; Whiting, Paul; Brown, Lisa S; Borthwick, Mark

2016-04-01

Clinical pharmacist practice is well established in the safe and effective use of medicines in the critically ill patient. In the UK, independent pharmacist prescribers are generally recognised as a valuable and desirable resource. However, currently, there are only anecdotal reports of pharmacist-independent prescribing in critical care. The aim of this questionnaire was to determine the current and proposed future independent prescribing practice of UK clinical pharmacists working in adult critical care. The questionnaire was distributed electronically to UK Clinical Pharmacy Association members (closed August 2014). There were 134 responses to the questionnaire (response rate at least 33%). Over a third of critical care pharmacists were practising independent prescribers in the specialty, and 70% intended to be prescribers within the next 3 years. Pharmacists with ≥5 years critical care experience (P < 0.001) or worked in a team (P = 0.005) were more likely to be practising independent prescribers. Pharmacists reported significant positives to the use of independent prescribing in critical care both in patient care and job satisfaction. Independently, prescribing was routine in: dose adjustment for multi-organ failure, change in route or formulation, correction prescribing errors, therapeutic drug monitoring and chronic medication. The majority of pharmacist prescribers reported they spent ≤5% of their clinical time prescribing and accounted for ≤5% of new prescriptions in critical care patients. Most critical care pharmacists intend to be practising as independent prescribers within the next 3 years. The extent and scope of critical care pharmacist prescribing appear to be of relatively low volume and within niche prescribing areas. © 2015 Royal Pharmaceutical Society.

Psychobiological responses to critically evaluated multitasking.

PubMed

Wetherell, Mark A; Craw, Olivia; Smith, Kenny; Smith, Michael A

2017-12-01

In order to understand psychobiological responses to stress it is necessary to observe how people react to controlled stressors. A range of stressors exist for this purpose; however, laboratory stressors that are representative of real life situations provide more ecologically valid opportunities for assessing stress responding. The current study assessed psychobiological responses to an ecologically valid laboratory stressor involving multitasking and critical evaluation. The stressor elicited significant increases in psychological and cardiovascular stress reactivity; however, no cortisol reactivity was observed. Other socially evaluative laboratory stressors that lead to cortisol reactivity typically require a participant to perform tasks that involve verbal responses, whilst standing in front of evaluative others. The current protocol contained critical evaluation of cognitive performance; however, this was delivered from behind a seated participant. The salience of social evaluation may therefore be related to the response format of the task and the method of evaluation. That is, the current protocol did not involve the additional vulnerability associated with in person, face-to-face contact, and verbal delivery. Critical evaluation of multitasking provides an ecologically valid technique for inducing laboratory stress and provides an alternative tool for assessing psychological and cardiovascular reactivity. Future studies could additionally use this paradigm to investigate those components of social evaluation necessary for eliciting a cortisol response.

Bulk critical state and fundamental length scales of superconducting nanocrystalline Nb3Al in Nb-Al matrix

NASA Astrophysics Data System (ADS)

Mondal, Puspen; Manekar, Meghmalhar; Srivastava, A. K.; Roy, S. B.

2009-07-01

We present the results of magnetization measurements on an as-cast nanocrystalline Nb3Al superconductor embedded in Nb-Al matrix. The typical grain size of Nb3Al ranges from about 2-8 nm with the maximum number of grains at around 3.5 nm, as visualized using transmission electron microscopy. The isothermal magnetization hysteresis loops in the superconducting state can be reasonably fitted within the well-known Kim-Anderson critical-state model. By using the same fitting parameters, we calculate the variation in field with respect to distance inside the sample and show the existence of a critical state over length scales much larger than the typical size of the superconducting grains. Our results indicate that a bulk critical current is possible in a system comprising of nanoparticles. The nonsuperconducting Nb-Al matrix thus appears to play a major role in the bulk current flow through the sample. The superconducting coherence length ξ is estimated to be around 3 nm, which is comparable to the typical grain size. The penetration depth λ is estimated to be about 94 nm, which is much larger than the largest of the superconducting grains. Our results could be useful for tuning the current carrying capability of conductors made out of composite materials which involve superconducting nanoparticles.

Learning and Olfaction: Understanding and Enhancing a Critical Information Channel

DTIC Science & Technology

2013-05-13

a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. a ...REPORT Learning and Olfaction: Understanding and Enhancing a Critical Information Channel 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: This research...Prescribed by ANSI Std. Z39.18 - 14-Feb-2013 Learning and Olfaction: Understanding and Enhancing a Critical Information Channel Report Title ABSTRACT This

Estrogen Metabolism and Breast Cancer

PubMed Central

Samavat, Hamed; Kurzer, Mindy S

2015-01-01

There is currently accumulating evidence that endogenous estrogens play a critical role in the development of breast cancer. Estrogens and their metabolites have been studied in both pre- and postmenopausal women with more consistent results shown in the latter population, in part because of large hormonal variations during the menstrual cycle and far fewer studies having been performed in premenopausal women. In this review we describe in detail estrogen metabolism and associated genetic variations, and provide a critical review of the current literature regarding the role of estrogens and their metabolites in breast cancer risk. PMID:24784887

Leap Frog Digital Sensors and Definition, Integration & Testing FY 2003 Annual Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meitzler, Wayne D.; Ouderkirk, Steven J.; Shoemaker, Steven V.

2003-12-31

The objective of Leap Frog is to develop a comprehensive security tool that is transparent to the user community and more effective than current methods for preventing and detecting security compromises of critical physical and digital assets. Current security tools intrude on the people that interact with these critical assets by requiring them to perform additional functions or having additional visible sensors. Leap Frog takes security to the next level by being more effective and reducing the adverse impact on the people interacting with protected assets.

Routine Work Environment Stress and PTSD Symptoms in Police Officers

PubMed Central

Maguen, Shira; Metzler, Thomas J.; McCaslin, Shannon E.; Inslicht, Sabra S.; Henn-Haase, Clare; Neylan, Thomas C.; Marmar, Charles R.

2013-01-01

This study examined the relationship between routine work environment stress and posttraumatic stress disorder (PTSD) symptoms in a sample of police officers (N = 180) who were first assessed during academy training and reassessed 1-year later. In a model that included gender, ethnicity, traumatic exposure prior to entering the academy, current negative life events, and critical incident exposure over the last year, routine work environment stress was most strongly associated with PTSD symptoms. We also found that routine work environment stress mediated the relationship between critical incident exposure and PTSD symptoms and between current negative life events and PTSD symptoms. Ensuring that the work environment is functioning optimally protects against the effects of duty-related critical incidents and negative life events outside police service. PMID:19829204

An Ethic of Democratic, Curriculum-Based Teacher Leadership

ERIC Educational Resources Information Center

Castner, Daniel J.; Schneider, Jennifer L.; Henderson, James G.

2017-01-01

This article opens with an overview of the current policy interest in "teacher leadership" with its particular challenges and opportunities. Teacher-leader interpretations based on standardized instructional management platforms grounded in neoliberalism are critically challenged. The referent for this critical questioning is a normative…

Politicizing Critical Pedagogies for the Logic of Late Capitalism

ERIC Educational Resources Information Center

Rice, J. A.

2008-01-01

In current critical pedagogy theory, the term "globalization" frequently signifies the rapid homogenization and structural equivalency of material and intellectual differences into a unified, transnational, capitalist rationality. For many composition scholars, this homogeneity signals an interpellation of not just subjects, but any and…

Trends Reshaping Colleges.

ERIC Educational Resources Information Center

Campbell, Dale F.; Peek, Roger C.

2002-01-01

Examines current educational trends in the community colleges, based on critical issues addressed at the 2002 Community College Futures Assembly (CCFA) in Orlando, Florida. Describes the CCFA as an independent policy forum, sponsored by the University of Florida, that convenes annually. Discusses the top three critical issues presented: the needs…

Critical acid load limits in a changing climate: implications and solutions

Treesearch

Steven G. McNulty

2010-01-01

The federal agencies of the United States are currently developing guidelines for critical nitrogen load limits for U.S. forest ecosystems. These guidelines will be used to develop regulations designed to maintain pollutant inputs below the level shown to damage specified ecosystems.

Preliminary Report on Mission Design and Operations for Critical Events

NASA Technical Reports Server (NTRS)

Hayden, Sandra C.; Tumer, Irem

2005-01-01

Mission-critical events are defined in the Jet Propulsion Laboratory s Flight Project Practices as those sequences of events which must succeed in order to attain mission goals. These are dependent on the particular operational concept and design reference mission, and are especially important when committing to irreversible events. Critical events include main engine cutoff (MECO) after launch; engine cutoff or parachute deployment on entry, descent, and landing (EDL); orbital insertion; separation of payload from vehicle or separation of booster segments; maintenance of pointing accuracy for power and communication; and deployment of solar arrays and communication antennas. The purpose of this paper is to report on the current practices in handling mission-critical events in design and operations at major NASA spaceflight centers. The scope of this report includes NASA Johnson Space Center (JSC), NASA Goddard Space Flight Center (GSFC), and NASA Jet Propulsion Laboratory (JPL), with staff at each center consulted on their current practices, processes, and procedures.

Office of Biological and Physical Research: Overview Transitioning to the Vision for Space Exploration

NASA Technical Reports Server (NTRS)

Crouch, Roger

2004-01-01

Viewgraphs on NASA's transition to its vision for space exploration is presented. The topics include: 1) Strategic Directives Guiding the Human Support Technology Program; 2) Progressive Capabilities; 3) A Journey to Inspire, Innovate, and Discover; 4) Risk Mitigation Status Technology Readiness Level (TRL) and Countermeasures Readiness Level (CRL); 5) Biological And Physical Research Enterprise Aligning With The Vision For U.S. Space Exploration; 6) Critical Path Roadmap Reference Missions; 7) Rating Risks; 8) Current Critical Path Roadmap (Draft) Rating Risks: Human Health; 9) Current Critical Path Roadmap (Draft) Rating Risks: System Performance/Efficiency; 10) Biological And Physical Research Enterprise Efforts to Align With Vision For U.S. Space Exploration; 11) Aligning with the Vision: Exploration Research Areas of Emphasis; 12) Code U Efforts To Align With The Vision For U.S. Space Exploration; 13) Types of Critical Path Roadmap Risks; and 14) ISS Human Support Systems Research, Development, and Demonstration. A summary discussing the vision for U.S. space exploration is also provided.

Critical Dimensions of Water-tamped Slabs and Spheres of Active Material

DOE R&D Accomplishments Database

Greuling, E.; Argo, H.: Chew, G.; Frankel, M. E.; Konopinski, E.J.; Marvin, C.; Teller, E.

1946-08-06

The magnitude and distribution of the fission rate per unit area produced by three energy groups of moderated neutrons reflected from a water tamper into one side of an infinite slab of active material is calculated approximately in section II. This rate is directly proportional to the current density of fast neutrons from the active material incident on the water tamper. The critical slab thickness is obtained in section III by solving an inhomogeneous transport integral equation for the fast-neutron current density into the tamper. Extensive use is made of the formulae derived in "The Mathematical Development of the End-Point Method" by Frankel and Goldberg. In section IV slight alterations in the theory outlined in sections II and III were made so that one could approximately compute the critical radius of a water-tamper sphere of active material. The derived formulae were applied to calculate the critical dimensions of water-tamped slabs and spheres of solid UF{sub 6} leaving various (25) isotope enrichment fractions. Decl. Dec. 16, 1955.

FEMCAM Analysis of SULTAN Test Results for ITER Nb3SN Cable-conduit Conductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuhu Zhai, Pierluigi Bruzzone, Ciro Calzolaio

2013-03-19

Performance degradation due to filament fracture of Nb3 Sn cable-in-conduit conductors (CICCs) is a critical issue in large-scale magnet designs such as ITER which is currently being constructed in the South of France. The critical current observed in most SULTAN TF CICC samples is significantly lower than expected and the voltage-current characteristic is seen to have a much broader transition from a single strand to the CICC. Moreover, most conductors exhibit the irreversible degradation due to filament fracture and strain relaxation under electromagnetic cyclic loading. With recent success in monitoring thermal strain distribution and its evolution under the electromagnetic cyclicmore » loading from in situ measurement of critical temperature, we apply FEMCAM which includes strand filament breakage and local current sharing effects to SULTAN tested CICCs to study Nb3 Sn strain sensitivity and irreversible performance degradation. FEMCAM combines the thermal bending effect during cool down and the EM bending effect due to locally accumulating Lorentz force during magnet operation. It also includes strand filament fracture and related local current sharing for the calculation of cable n value. In this paper, we model continuous performance degradation under EM cyclic loading based on strain relaxation and the transition broadening upon cyclic loading to the extreme cases seen in SULTAN test data to better quantify conductor performance degradation.« less

Automatic Identification of Critical Data Items in a Database to Mitigate the Effects of Malicious Insiders

NASA Astrophysics Data System (ADS)

White, Jonathan; Panda, Brajendra

A major concern for computer system security is the threat from malicious insiders who target and abuse critical data items in the system. In this paper, we propose a solution to enable automatic identification of critical data items in a database by way of data dependency relationships. This identification of critical data items is necessary because insider threats often target mission critical data in order to accomplish malicious tasks. Unfortunately, currently available systems fail to address this problem in a comprehensive manner. It is more difficult for non-experts to identify these critical data items because of their lack of familiarity and due to the fact that data systems are constantly changing. By identifying the critical data items automatically, security engineers will be better prepared to protect what is critical to the mission of the organization and also have the ability to focus their security efforts on these critical data items. We have developed an algorithm that scans the database logs and forms a directed graph showing which items influence a large number of other items and at what frequency this influence occurs. This graph is traversed to reveal the data items which have a large influence throughout the database system by using a novel metric based formula. These items are critical to the system because if they are maliciously altered or stolen, the malicious alterations will spread throughout the system, delaying recovery and causing a much more malignant effect. As these items have significant influence, they are deemed to be critical and worthy of extra security measures. Our proposal is not intended to replace existing intrusion detection systems, but rather is intended to complement current and future technologies. Our proposal has never been performed before, and our experimental results have shown that it is very effective in revealing critical data items automatically.

78 FR 73202 - Review and Revision of the National Critical Infrastructure Security and Resilience (NCISR...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-05

...This Request for Information (RFI) notice informs the public that the Department of Homeland Security's (DHS) Science and Technology Directorate (S&T) is currently developing a National Critical Infrastructure Security and Resilience Research and Development Plan (NCISR R&D Plan) to conform to the requirements of Presidential Policy Directive 21, Critical Infrastructure Security and Resilience. As part of a comprehensive national review process, DHS solicits public comment on issues or language in the NCISR R&D Plan that need to be included. Critical infrastructure includes both cyber and physical components, systems, and networks for the sixteen established ``critical infrastructures''.

Pb/InAs nanowire josephson junction with high critical current and magnetic flux focusing.

PubMed

Paajaste, J; Amado, M; Roddaro, S; Bergeret, F S; Ercolani, D; Sorba, L; Giazotto, F

2015-03-11

We have studied mesoscopic Josephson junctions formed by highly n-doped InAs nanowires and superconducting Ti/Pb source and drain leads. The current-voltage properties of the system are investigated by varying temperature and external out-of-plane magnetic field. Superconductivity in the Pb electrodes persists up to ∼7 K and with magnetic field values up to 0.4 T. Josephson coupling at zero backgate voltage is observed up to 4.5 K and the critical current is measured to be as high as 615 nA. The supercurrent suppression as a function of the magnetic field reveals a diffraction pattern that is explained by a strong magnetic flux focusing provided by the superconducting electrodes forming the junction.

Probe-Substrate Distance Control in Desorption Electrospray Ionization

NASA Astrophysics Data System (ADS)

Yarger, Tyler J.; Yuill, Elizabeth M.; Baker, Lane A.

2018-03-01

We introduce probe-substrate distance (Dps)-control to desorption electrospray ionization (DESI) and report a systematic investigation of key experimental parameters. Examination of voltage, flow rate, and nebulizing gas pressure suggests as Dps decreases, the distance-dependent spray current increases, until a critical point. At the critical point the relationship inverts, and the spray current decreases as the probe moves closer to the surface due to constriction of solution flow by the nebulizing gas. Dps control was used to explore the use of spray current as a signal for feedback positioning, while mass spectrometry imaging was performed simultaneously. Further development of this technique is expected to find application in study of structure-function relationships for clinical diagnostics, biological investigation, and materials characterization. [Figure not available: see fulltext.

Cybersecurity: The Nation’s Greatest Threat to Critical Infrastructure

DTIC Science & Technology

2013-03-01

protection has become a matter of national security, public safety, and economic stability . It is imperative the U.S. Government (USG) examine current...recommendations for federal responsibilities and legislation to direct nation critical infrastructure efforts to ensure national security, public safety and economic stability .

Who Needs Critical Agency?: Educational Research and the Rhetorical Economy of Globalization

ERIC Educational Resources Information Center

Rice, J. A.; Vastola, Michael

2011-01-01

Current critical pedagogical scholarship has theorized the epistemological and social intersection between globalization and educational technology according to two distinct positions. For some, this intersection offers new liberatory knowledges and opportunities that can subvert social homogenization and economic disparity. For others, this…

Questions of Matter: Critical Conversations in Online Spaces

ERIC Educational Resources Information Center

Albers, Peggy; Turnbull, Sarah; Angay-Crowder, Tuba

2015-01-01

How professional development is delivered in today's networked world has shifted greatly, and research into online spaces of learning is growing. Numerous questions, however, remain regarding how online spaces can be leveraged to foster meaningful conversations that address current critical educational issues. This qualitative study examines the…

Music, the Humanities, and "A Sense of Where You Are."

ERIC Educational Resources Information Center

Delattre, Edwin J.

1995-01-01

Criticizes current educational trends, specifically the lack of critical standards and the tendency to sacrifice content in favor of promoting self-esteem. Argues that the depth and greatness of the humanities is lost in classrooms infatuated with feel-good activities and cultural relativism. (MJP)

Bridging Fields at a Critical Time

ERIC Educational Resources Information Center

Baggaley, Jon

2014-01-01

The launch of the "Journal of Learning for Development" occurs at a critical time for the education and development field. The "massive open online course" concept currently being implemented by Western educators is considered as a potential cost-saver in developing nations also. MOOCs based on reliable pedagogical principles…

Dialogic Spaces: A Critical Policy Development Perspective of Educational Leadership Qualifications

ERIC Educational Resources Information Center

Smith, Déirdre; Kelly, Darron; Allard, Carson

2017-01-01

The critical exploration of policy development processes employed to construct leadership qualifications is the focus of this inquiry. This exploration is made through specific application of the necessary conditions of Habermasian "practical discourse" to current dialogic procedures used to develop policies for principal, supervisory…

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

PubMed

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 adolescence. An understanding of adult patients' past peer relationships may further the therapist's understanding of the client's core schemas and dysfunctional attitudes, as well as potential transference reactions during therapy. Identifying and helping youth to better cope with peer victimization may help prevent the development of a vulnerable personality style in adulthood. Fostering positive peer relationships in adolescence may buffer the effects of other more negative relationships with peers. © 2011 The British Psychological Society.

Pulsed Eddy Current Sensing for Critical Pipe Condition Assessment

PubMed Central

2017-01-01

Pulsed Eddy Current (PEC) sensing is used for Non-Destructive Evaluation (NDE) of the structural integrity of metallic structures in the aircraft, railway, oil and gas sectors. Urban water utilities also have extensive large ferromagnetic structures in the form of critical pressure pipe systems made of grey cast iron, ductile cast iron and mild steel. The associated material properties render NDE of these pipes by means of electromagnetic sensing a necessity. In recent years PEC sensing has established itself as a state-of-the-art NDE technique in the critical water pipe sector. This paper presents advancements to PEC inspection in view of the specific information demanded from water utilities along with the challenges encountered in this sector. Operating principles of the sensor architecture suitable for application on critical pipes are presented with the associated sensor design and calibration strategy. A Gaussian process-based approach is applied to model a functional relationship between a PEC signal feature and critical pipe wall thickness. A case study demonstrates the sensor’s behaviour on a grey cast iron pipe and discusses the implications of the observed results and challenges relating to this application. PMID:28954392

Universal current-velocity relation of skyrmion motion in chiral magnets

NASA Astrophysics Data System (ADS)

Iwasaki, Junichi; Mochizuki, Masahito; Nagaosa, Naoto

2013-02-01

Current-driven motion of the magnetic domain wall in ferromagnets is attracting intense attention because of potential applications such as racetrack memory. There, the critical current density to drive the motion is ~109-1012 A m-2. The skyrmions recently discovered in chiral magnets have much smaller critical current density of ~105-106 A m-2, but the microscopic mechanism is not yet explored. Here we present a numerical simulation of Landau-Lifshitz-Gilbert equation, which reveals a remarkably robust and universal current-velocity relation of the skyrmion motion driven by the spin-transfer-torque unaffected by either impurities or nonadiabatic effect in sharp contrast to the case of domain wall or spin helix. Simulation results are analysed using a theory based on Thiele’s equation, and it is concluded that this behaviour is due to the Magnus force and flexible shape-deformation of individual skyrmions and skyrmion crystal, which enable them to avoid pinning centres.

Current-induced SQUID behavior of superconducting Nb nano-rings

NASA Astrophysics Data System (ADS)

Sharon, Omri J.; Shaulov, Avner; Berger, Jorge; Sharoni, Amos; Yeshurun, Yosef

2016-06-01

The critical temperature in a superconducting ring changes periodically with the magnetic flux threading it, giving rise to the well-known Little-Parks magnetoresistance oscillations. Periodic changes of the critical current in a superconducting quantum interference device (SQUID), consisting of two Josephson junctions in a ring, lead to a different type of magnetoresistance oscillations utilized in detecting extremely small changes in magnetic fields. Here we demonstrate current-induced switching between Little-Parks and SQUID magnetoresistance oscillations in a superconducting nano-ring without Josephson junctions. Our measurements in Nb nano-rings show that as the bias current increases, the parabolic Little-Parks magnetoresistance oscillations become sinusoidal and eventually transform into oscillations typical of a SQUID. We associate this phenomenon with the flux-induced non-uniformity of the order parameter along a superconducting nano-ring, arising from the superconducting leads (‘arms’) attached to it. Current enhanced phase slip rates at the points with minimal order parameter create effective Josephson junctions in the ring, switching it into a SQUID.

Controlling Hysteresis in Superconducting Weak Links and μ-Superconducting Quantum Interference Devices

NASA Astrophysics Data System (ADS)

Kumar, Nikhil; Winkelmann, C. B.; Biswas, Sourav; Courtois, H.; Gupta, Anjan K.

We have fabricated and studied the current-voltage characteristics of a number of niobium film based weak-link devices and μ-SQUIDs showing a critical current and two re-trapping currents. We have proposed a new understanding for the re-trapping currents in terms of thermal instabilities in different portions of the device. We also find that the superconducting proximity effect and the phase-slip processes play an important role in dictating the temperature dependence of the critical current in the non-hysteretic regime. The proximity effect helps in widening the temperature range of hysteresis-free characteristics. Finally we demonstrate control on temperature-range with hysteresis-free characteristics in two ways: 1) By using a parallel shunt resistor in close vicinity of the device, and 2) by reducing the weak-link width. Thus we get non-hysteretic behavior down to 1.3 K temperature in some of the studied devices. We acknowledge the financial support from CSIR, India as well as CNRS-Institute Neel, Grenoble, France.

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

NASA Astrophysics Data System (ADS)

Glowacki, B. A.; Majoros, M.

2009-06-01

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 YBa2Cu3O7 and (Pb,Bi)2Sr2Ca2Cu3O9 conductors, and buffer layers have to be used. In contrast, in MgB2 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.

Nuclear Weapons: Comprehensive Test Ban Treaty

DTIC Science & Technology

2007-05-24

remain current. It indicated plans to reduce the time between a decision to conduct a nuclear test and the test itself, which has been done. Critics ...over the Summit,” Manila Bulletin, August 27, 2005. Critics expressed concern about the implications of these policies for testing and new weapons...force, seek the opportunity to design and build new nuclear weapons, and abandon a ten-year-old moratorium on nuclear weapons testing.”8 Another critic

Transport properties of gases and binary liquids near the critical point

NASA Technical Reports Server (NTRS)

Sengers, J. V.

1972-01-01

A status report is presented on the anomalies observed in the behavior of transport properties near the critical point of gases and binary liquids. The shear viscosity exhibits a weak singularity near the critical point. An analysis is made of the experimental data for those transport properties, thermal conductivity and thermal diffusivity near the gas-liquid critical point and binary diffusion coefficient near the critical mixing point, that determine the critical slowing down of the thermodynamic fluctuations in the order parameter. The asymptotic behavior of the thermal conductivity appears to be closely related to the asymptotic behavior of the correlation length. The experimental data for the thermal conductivity and diffusivity are shown to be in substantial agreement with current theoretical predictions.

The role of health information technology on critical care services in Thailand.

PubMed

Wacharasint, Petch

2014-01-01

Health information technology (IT) has become an important part of current medical practice, especially in critical care services. One significant advance is the use of telemedicine which was initiated in Thailand nearly two decades ago. Telemedicine is also used in the intensive care unit or what has been termed the "Tele-ICU". It has evolved as an alternate paradigm linking the intensivist and critical care specialists to critically ill patients in remote areas. In this article, the author has reviewed the evidence of health IT on critical care services in Thailand, focusing on telemedicine, as well as the concept of the 'Tele-ICU' and its challenges. These factors may assist intensivists to reach more critically ill patients in remote areas.

Dependence of transition width on current and critical current in transition-edge sensors

NASA Astrophysics Data System (ADS)

Morgan, K. M.; Pappas, C. G.; Bennett, D. A.; Gard, J. D.; Hays-Wehle, J. P.; Hilton, G. C.; Reintsema, C. D.; Schmidt, D. R.; Ullom, J. N.; Swetz, D. S.

2017-05-01

In superconducting transition-edge sensor X-ray detectors, we observe that as the thermal conductance (G) to the heat bath increases, the resistive transition broadens. Consequently, the sensitivity of films to deposited energy worsens. Using a two-fluid model for the superconducting-to-normal transition in a thin film, we show that this broadening can be attributed to the larger current (I0) necessary for biasing the film at a given point in the transition for higher-G devices, resulting in a higher Ic0/I0 ratio (Ic0 is the film's critical current at zero temperature). To recover a sharper transition, we fabricated rectangular films with varying numbers of internal normal-metal structures while keeping G constant, allowing the independent variation of both I0 and Ic0. We show that it is possible to manipulate the transition width and G independently, thus enabling fast thermal sensors with an excellent energy resolution.

Comparison of Low-Molecular-Weight Heparins Prepared From Bovine Heparins With Enoxaparin.

PubMed

Liu, Xinyue; St Ange, Kalib; Fareed, Jawed; Hoppensteadt, Debra; Jeske, Walter; Kouta, Ahmed; Chi, Lianli; Jin, Caijuan; Jin, Yongsheng; Yao, Yiming; Linhardt, Robert J

2017-09-01

Heparin and its low-molecular-weight heparin (LMWH) derivatives are widely used clinical anticoagulants. These drugs are critical for the practice of medicine in applications including kidney dialysis, cardiopulmonary bypass, and in the management of venous thromboembolism. Currently, these drugs are derived from livestock, primarily porcine intestine. The worldwide dependence on a single animal species has made the supply chain for this critical drug quite fragile, leading to the search for other sources of these drugs, including bovine tissues such as bovine intestine or lung. A number of laboratories are currently examining the similarities and differences between heparins prepared from porcine and bovine tissues. The current study is designed to compare LMWH prepared from bovine heparins through chemical β-elimination, a process currently used to prepare the LMWH, enoxaparin, from porcine heparin. Using top-down, bottom-up, compositional analysis and bioassays, LMWHs, derived from bovine lung and intestine, are shown to closely resemble enoxaparin.

The role of minimum supply and social vulnerability assessment for governing critical infrastructure failure: current gaps and future agenda

NASA Astrophysics Data System (ADS)

Garschagen, Matthias; Sandholz, Simone

2018-04-01

Increased attention has lately been given to the resilience of critical infrastructure in the context of natural hazards and disasters. The major focus therein is on the sensitivity of critical infrastructure technologies and their management contingencies. However, strikingly little attention has been given to assessing and mitigating social vulnerabilities towards the failure of critical infrastructure and to the development, design and implementation of minimum supply standards in situations of major infrastructure failure. Addressing this gap and contributing to a more integrative perspective on critical infrastructure resilience is the objective of this paper. It asks which role social vulnerability assessments and minimum supply considerations can, should and do - or do not - play for the management and governance of critical infrastructure failure. In its first part, the paper provides a structured review on achievements and remaining gaps in the management of critical infrastructure and the understanding of social vulnerabilities towards disaster-related infrastructure failures. Special attention is given to the current state of minimum supply concepts with a regional focus on policies in Germany and the EU. In its second part, the paper then responds to the identified gaps by developing a heuristic model on the linkages of critical infrastructure management, social vulnerability and minimum supply. This framework helps to inform a vision of a future research agenda, which is presented in the paper's third part. Overall, the analysis suggests that the assessment of socially differentiated vulnerabilities towards critical infrastructure failure needs to be undertaken more stringently to inform the scientifically and politically difficult debate about minimum supply standards and the shared responsibilities for securing them.

Nonequilibrium phase diagram of a one-dimensional quasiperiodic system with a single-particle mobility edge

NASA Astrophysics Data System (ADS)

Purkayastha, Archak; Dhar, Abhishek; Kulkarni, Manas

2017-11-01

We investigate and map out the nonequilibrium phase diagram of a generalization of the well known Aubry-André-Harper (AAH) model. This generalized AAH (GAAH) model is known to have a single-particle mobility edge which also has an additional self-dual property akin to that of the critical point of the AAH model. By calculating the population imbalance, we get hints of a rich phase diagram. We also find a fascinating connection between single particle wave functions near the mobility edge of the GAAH model and the wave functions of the critical AAH model. By placing this model far from equilibrium with the aid of two baths, we investigate the open system transport via system size scaling of nonequilibrium steady state (NESS) current, calculated by fully exact nonequilibrium Green's function (NEGF) formalism. The critical point of the AAH model now generalizes to a `critical' line separating regions of ballistic and localized transport. Like the critical point of the AAH model, current scales subdiffusively with system size on the `critical' line (I ˜N-2 ±0.1 ). However, remarkably, the scaling exponent on this line is distinctly different from that obtained for the critical AAH model (where I ˜N-1.4 ±0.05 ). All these results can be understood from the above-mentioned connection between states near the mobility edge of the GAAH model and those of the critical AAH model. A very interesting high temperature nonequilibrium phase diagram of the GAAH model emerges from our calculations.

Psycholinguistic Techniques and Resources in Second Language Acquisition Research

ERIC Educational Resources Information Center

Roberts, Leah

2012-01-01

In this article, a survey of current psycholinguistic techniques relevant to second language acquisition (SLA) research is presented. I summarize many of the available methods and discuss their use with particular reference to two critical questions in current SLA research: (1) What does a learner's current knowledge of the second language (L2)…

77 FR 37332 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-21

... the high frequency eddy current inspection for cracking of the critical fastener holes, and repair if... of the bulkhead, and repair if necessary; and proposed an option to the high frequency eddy current...-15152 (72 FR 44753, August 9, 2007)), do a high frequency eddy current (HFEC) inspection for cracking of...

Strongly enhanced current densities in Sr0.6K0.4Fe2As2 + Sn superconducting tapes.

PubMed

Lin, He; Yao, Chao; Zhang, Xianping; Zhang, Haitao; Wang, Dongliang; Zhang, Qianjun; Ma, Yanwei; Awaji, Satoshi; Watanabe, Kazuo

2014-03-25

Improving transport current has been the primary topic for practical application of superconducting wires and tapes. However, the porous nature of powder-in-tube (PIT) processed iron-based tapes is one of the important reasons for low critical current density (Jc) values. In this work, the superconducting core density of ex-situ Sr0.6K0.4Fe2As2 + Sn tapes, prepared from optimized precursors, was significantly improved by employing a simple hot pressing as an alternative route for final sintering. The resulting samples exhibited optimal critical temperature (Tc), sharp resistive transition, small resistivity and high Vickers hardness (Hv) value. Consequently, the transport Jc reached excellent values of 5.1 × 10(4) A/cm(2) in 10 T and 4.3 × 10(4) A/cm(2) in 14 T at 4.2 K, respectively. Our tapes also exhibited high upper critical field Hc2 and almost field-independent Jc. These results clearly demonstrate that PIT pnictide wire conductors are very promising for high-field magnet applications.

Strongly enhanced current densities in Sr0.6K0.4Fe2As2 + Sn superconducting tapes

PubMed Central

Lin, He; Yao, Chao; Zhang, Xianping; Zhang, Haitao; Wang, Dongliang; Zhang, Qianjun; Ma, Yanwei; Awaji, Satoshi; Watanabe, Kazuo

2014-01-01

Improving transport current has been the primary topic for practical application of superconducting wires and tapes. However, the porous nature of powder-in-tube (PIT) processed iron-based tapes is one of the important reasons for low critical current density (Jc) values. In this work, the superconducting core density of ex-situ Sr0.6K0.4Fe2As2 + Sn tapes, prepared from optimized precursors, was significantly improved by employing a simple hot pressing as an alternative route for final sintering. The resulting samples exhibited optimal critical temperature (Tc), sharp resistive transition, small resistivity and high Vickers hardness (Hv) value. Consequently, the transport Jc reached excellent values of 5.1 × 104 A/cm2 in 10 T and 4.3 × 104 A/cm2 in 14 T at 4.2 K, respectively. Our tapes also exhibited high upper critical field Hc2 and almost field-independent Jc. These results clearly demonstrate that PIT pnictide wire conductors are very promising for high-field magnet applications. PMID:24663054

Critical current of SF-NFS Josephson junctions

NASA Astrophysics Data System (ADS)

Soloviev, I. I.; Klenov, N. V.; Bakursky, S. V.; Kupriyanov, M. Yu.; Golubov, A. A.

2015-02-01

The properties of SF-NFS sandwiches composed of two superconducting (S) electrodes separated by a weak-link region formed by a normal-metal (N) step with the thickness d N situated on the top of a lower S electrode and a ferromagnetic (F) layer with the thickness d F deposited onto the step and the remaining free surface of the lower electrode have been studied theoretically. It has been shown in the approximation of linearized semiclassical Usadel equations that the two-dimensional problem in the weak-link region can be reduced to two one-dimensional problems in its SFS and SNFS segments. The spatial distributions of the critical current density J c in the segments as a function of the layer thickness d F have been calculated. The dependences of the critical current I c of the structure on the magnitude of the magnetization vector M of the ferromagnetic layer have been found for various directions of the magnetization within the junction plane. It has been shown that these dependences are affected considerably by both the orientation of M and the spatial distribution of J c.

Measuring the critical band for speech.

PubMed

Healy, Eric W; Bacon, Sid P

2006-02-01

The current experiments were designed to measure the frequency resolution employed by listeners during the perception of everyday sentences. Speech bands having nearly vertical filter slopes and narrow bandwidths were sharply partitioned into various numbers of equal log- or ERBN-width subbands. The temporal envelope from each partition was used to amplitude modulate a corresponding band of low-noise noise, and the modulated carriers were combined and presented to normal-hearing listeners. Intelligibility increased and reached asymptote as the number of partitions increased. In the mid- and high-frequency regions of the speech spectrum, the partition bandwidth corresponding to asymptotic performance matched current estimates of psychophysical tuning across a number of conditions. These results indicate that, in these regions, the critical band for speech matches the critical band measured using traditional psychoacoustic methods and nonspeech stimuli. However, in the low-frequency region, partition bandwidths at asymptote were somewhat narrower than would be predicted based upon psychophysical tuning. It is concluded that, overall, current estimates of psychophysical tuning represent reasonably well the ability of listeners to extract spectral detail from running speech.

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

DOE PAGES

Ozaki, Toshinori; Li, Qiang; Wu, Lijun; ...

2016-10-06

The critical temperature T c and the critical current density J c determine the limits to large-scale superconductor applications. Superconductivity emerges at T c. The practical current-carrying capability, measured by J c, is the ability of defects in superconductors to pin the magnetic vortices, and that may reduce T c. Simultaneous increase of T c and J c in superconductors is desirable but very difficult to realize. Here we demonstrate a route to raise both T c and J c together in iron-based superconductors. By using low-energy proton irradiation, we create cascade defects in FeSe 0.5Te 0.5 films. Tc ismore » enhanced due to the nanoscale compressive strain and proximity effect, whereas J c 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 J c enhancement is achieved in both parallel and perpendicular magnetic fields to the film surface.« less

Strongly enhanced current densities in Sr0.6K0.4Fe2As2 + Sn superconducting tapes

NASA Astrophysics Data System (ADS)

Lin, He; Yao, Chao; Zhang, Xianping; Zhang, Haitao; Wang, Dongliang; Zhang, Qianjun; Ma, Yanwei; Awaji, Satoshi; Watanabe, Kazuo

2014-03-01

Improving transport current has been the primary topic for practical application of superconducting wires and tapes. However, the porous nature of powder-in-tube (PIT) processed iron-based tapes is one of the important reasons for low critical current density (Jc) values. In this work, the superconducting core density of ex-situ Sr0.6K0.4Fe2As2 + Sn tapes, prepared from optimized precursors, was significantly improved by employing a simple hot pressing as an alternative route for final sintering. The resulting samples exhibited optimal critical temperature (Tc), sharp resistive transition, small resistivity and high Vickers hardness (Hv) value. Consequently, the transport Jc reached excellent values of 5.1 × 104 A/cm2 in 10 T and 4.3 × 104 A/cm2 in 14 T at 4.2 K, respectively. Our tapes also exhibited high upper critical field Hc2 and almost field-independent Jc. These results clearly demonstrate that PIT pnictide wire conductors are very promising for high-field magnet applications.

Development of practical high temperature superconducting wire for electric power application

NASA Technical Reports Server (NTRS)

Hawsey, Robert A.; Sokolowski, Robert S.; Haldar, Pradeep; Motowidlo, Leszek R.

1995-01-01

The technology of high temperature superconductivity has gone from beyond mere scientific curiousity into the manufacturing environment. Single lengths of multifilamentary wire are now produced that are over 200 meters long and that carry over 13 amperes at 77 K. Short-sample critical current densities approach 5 x 104 A/sq cm at 77 K. Conductor requirements such as high critical current density in a magnetic field, strain-tolerant sheathing materials, and other engineering properties are addressed. A new process for fabricating round BSCCO-2212 wire has produced wires with critical current densities as high as 165,000 A/sq cm at 4.2 K and 53,000 A/sq cm at 40 K. This process eliminates the costly, multiple pressing and rolling steps that are commonly used to develop texture in the wires. New multifilamentary wires with strengthened sheathing materials have shown improved yield strengths up to a factor of five better than those made with pure silver. Many electric power devices require the wire to be formed into coils for production of strong magnetic fields. Requirements for coils and magnets for electric power applications are described.

Military nutrition: maintaining health and rebuilding injured tissue.

PubMed

Hill, Neil; Fallowfield, Joanne; Price, Susan; Wilson, Duncan

2011-01-27

Food and nutrition are fundamental to military capability. Historical examples demonstrate that a failure to supply adequate nutrition to armies inevitably leads to disaster; however, innovative measures to overcome difficulties in feeding reap benefits, and save lives. In barracks, UK Armed Forces are currently fed according to the relatively new Pay As You Dine policy, which has attracted criticism from some quarters. The recently introduced Multi-Climate Ration has been developed specifically to deal with issues arising from Iraq and the current conflict in Afghanistan. Severely wounded military personnel are likely to lose a significant amount of their muscle mass, in spite of the best medical care. Nutritional support is unable to prevent this, but can ameliorate the effects of the catabolic process. Measuring and quantifying nutritional status during critical illness is difficult. A consensus is beginning to emerge from studies investigating the effects of nutritional interventions on how, what and when to feed patients with critical illness. The Ministry of Defence is currently undertaking research to address specific concerns related to nutrition as well as seeking to promote healthy eating in military personnel.

Military nutrition: maintaining health and rebuilding injured tissue

PubMed Central

Hill, Neil; Fallowfield, Joanne; Price, Susan; Wilson, Duncan

2011-01-01

Food and nutrition are fundamental to military capability. Historical examples demonstrate that a failure to supply adequate nutrition to armies inevitably leads to disaster; however, innovative measures to overcome difficulties in feeding reap benefits, and save lives. In barracks, UK Armed Forces are currently fed according to the relatively new Pay As You Dine policy, which has attracted criticism from some quarters. The recently introduced Multi-Climate Ration has been developed specifically to deal with issues arising from Iraq and the current conflict in Afghanistan. Severely wounded military personnel are likely to lose a significant amount of their muscle mass, in spite of the best medical care. Nutritional support is unable to prevent this, but can ameliorate the effects of the catabolic process. Measuring and quantifying nutritional status during critical illness is difficult. A consensus is beginning to emerge from studies investigating the effects of nutritional interventions on how, what and when to feed patients with critical illness. The Ministry of Defence is currently undertaking research to address specific concerns related to nutrition as well as seeking to promote healthy eating in military personnel. PMID:21149358

Exfoliated YBCO filaments for second-generation superconducting cable

NASA Astrophysics Data System (ADS)

Solovyov, Vyacheslav; Farrell, Paul

2017-01-01

The second-generation high temperature superconductor (2G HTS) wire is the most promising conductor for high-field magnets such as accelerator dipoles and compact fusion devices. The key element of the wire is a thin Y1Ba2Cu3O7 (YBCO) layer deposited on a flexible metal substrate. The substrate, which becomes incorporated in the 2G conductor, reduces the electrical and mechanical performance of the wire. This is a process that exfoliates the YBCO layer from the substrate while retaining the critical current density of the superconductor. Ten-centimeter long coupons of exfoliated YBCO layers were manufactured, and detailed structural, electrical, and mechanical characterization were reported. After exfoliation, the YBCO layer was supported by a 75 μm thick stainless steel foil, which makes for a compact, mechanically stronger, and inexpensive conductor. The critical current density of the filaments was measured at both 77 K and 4.2 K. The exfoliated YBCO retained 90% of the original critical current. Similarly, tests in an external magnetic field at 4.2 K confirmed that the pinning strength of the YBCO layer was also retained following exfoliation.

Project HOPE: A Career Education Program for Rural Middle School Students

ERIC Educational Resources Information Center

Hoffman, Tina D.

2013-01-01

A critical psychology perspective (Prilleltensky and Nelson, 2002) advocates for research that focuses on social change, the mutual participation of community stakeholders, and the empowerment of those served. The current study applies this critical psychology perspective to career education programming in a multiculturally diverse rural high…

Critically Engaging with Cultural Representations in Foreign Language Textbooks

ERIC Educational Resources Information Center

McConachy, Troy

2018-01-01

There is currently strong recognition within the field of intercultural language teaching of the need for language learners to develop the ability to actively interpret and critically reflect on cultural meanings and representations from a variety of perspectives. This article argues that cultural representations contained in language textbooks,…

Simulated and Virtual Science Laboratory Experiments: Improving Critical Thinking and Higher-Order Learning Skills

ERIC Educational Resources Information Center

Simon, Nicole A.

2013-01-01

Virtual laboratory experiments using interactive computer simulations are not being employed as viable alternatives to laboratory science curriculum at extensive enough rates within higher education. Rote traditional lab experiments are currently the norm and are not addressing inquiry, Critical Thinking, and cognition throughout the laboratory…

Critical Adult Education and the Art Gallery Museum

ERIC Educational Resources Information Center

Clover, Darlene E.

2018-01-01

Although burdened by legacies of elitism, exclusion and paternalism, some public museums are attempting to respond to the socio-environmental problems currently facing our planet by developing critical non-formal educational activities to foster consciousness and change. This article explores one such response; a six-week non-formal course…

Insight Problem Solving: A Critical Examination of the Possibility of Formal Theory

ERIC Educational Resources Information Center

Batchelder, William H.; Alexander, Gregory E.

2012-01-01

This paper provides a critical examination of the current state and future possibility of formal cognitive theory for insight problem solving and its associated "aha!" experience. Insight problems are contrasted with move problems, which have been formally defined and studied extensively by cognitive psychologists since the pioneering…

Nitrous oxide as a humane method for piglet euthanasia: behavior and electroencephalography

USDA-ARS?s Scientific Manuscript database

The search for humane methods to euthanize piglets is critical to address public concern that current methods are not optimal. Blunt force trauma is considered humane but aesthetically objectionable. Carbon dioxide (CO2) is used but criticized as aversive. This research sought to: 1) evaluate the av...

15 CFR 700.30 - Priorities and allocations in a national emergency.

Code of Federal Regulations, 2011 CFR

2011-01-01

... industrial response and the timely availability of critical industrial items and facilities to meet the... ensure the timely availability of these items and facilities for approved programs, and to provide for an... be used to assure the availability of any scarce and critical item for approved programs. Currently...

School Uniforms: A Critical Review of the Literature. From Inquiry to Practice.

ERIC Educational Resources Information Center

Brunsma, David L.

The debate surrounding the effectiveness of school-uniform policies, as well as discussions concerning when and how to implement them, is rooted in anecdote. This review summarizes anecdotal literature on which the current debate is based and critically reviews the empirical literature, including theoretical underpinnings, findings, and…

Postgraduate Research Supervision: A Critical Review of Current Practice

ERIC Educational Resources Information Center

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…

Technical Communication in the 21st Century: Where Are We Going?

ERIC Educational Resources Information Center

Killingsworth, M. Jimmie

1999-01-01

Explores how technical communicators arrive at their attitudes toward the future and the effects of such attitudes toward current practice. Argues for a critically informed, open-minded approach to the future, an approach that encourages an honest self-criticism within the discipline of technical communication. (SC)

A Critical Analysis of Anti-Discrimination Law and Microaggressions in Academia

ERIC Educational Resources Information Center

Lukes, Robin; Bangs, Joann

2014-01-01

This article provides a critical analysis of microaggressions and anti-discrimination law in academia. There are many challenges for faculty claiming discrimination under current civil rights laws. Examples of microaggressions that fall outside of anti-discrimination law will be provided. Traditional legal analysis of discrimination will not end…

The Construction of Pro-Science and Technology Discourse in Chinese Language Textbooks

ERIC Educational Resources Information Center

Liu, Yongbing

2005-01-01

This paper examines the pro-science and technology discourse constructed in Chinese language textbooks currently used for primary school students nationwide in China. By applying analytical techniques of critical discourse analysis (CDA), the paper critically investigates how the discourse is constructed and what ideological forces are manifested…

75 FR 37358 - Endangered and Threatened Wildlife and Plants; Revised Critical Habitat for the Arroyo Toad

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-29

... whether the DEA makes appropriate assumptions regarding current practices and any regulatory changes that... from adverse modification or destruction of critical habitat. In practice, situations with a Federal... Newhall Land and Farming Company (Newhall LFC). Newhall LFC developed the Natural River Management Plan...

Four Pillars for Improving the Quality of Safety-Critical Software-Reliant Systems

DTIC Science & Technology

2013-04-01

Studies of safety-critical software-reliant systems developed using the current practices of build-then-test show that requirements and architecture ... design defects make up approximately 70% of all defects, many system level related to operational quality attributes, and 80% of these defects are

Grammaticality as Evidence and as Prediction in a Galilean Linguistics

ERIC Educational Resources Information Center

Riemer, N.

2009-01-01

Standard criticisms of unjustified grammaticality assignments in generative syntax are easily countered by reminders that grammaticality is a different notion from acceptability. In response, the criticisms are reformulated here in a way that interprets unjustified assignments as possible evidence of the predictive failure of current generative…

The effect of transcranial direct current stimulation of the prefrontal cortex on implicit self-esteem is mediated by rumination after criticism.

PubMed

De Raedt, Rudi; Remue, Jonathan; Loeys, Tom; Hooley, Jill M; Baeken, Chris

2017-12-01

It has been proposed that a crucial link between cognitive (i.e., self-schemas) and biological vulnerability is prefrontal control. This is because decreased control leads to impaired ability to inhibit ruminative thinking after the activation of negative self-schemas. However, current evidence is mainly correlational. In the current experimental study we tested whether the effect of neurostimulation of the dorsolateral prefrontal cortex (DLPFC) on self-esteem is mediated by momentary ruminative self-referential thinking (MRST) after the induction of negative self-schemas by criticism. We used a single, sham-controlled crossover session of anodal transcranial Direct Current Stimulation (tDCS) applied to the left DLPFC (cathode over the right supraorbital region) in healthy female individuals. After receiving tDCS/sham stimulation, we measured MRST and exposed the participants to critical audio scripts, followed by another MRST measurement. Subsequently, all participants completed two Implicit Relational Assessment Procedures to implicitly measure actual and ideal self-esteem. Our behavioral data indicated a significant decrease in MRST after real but not sham tDCS. Moreover, although there was no immediate effect of tDCS on implicit self-esteem, an indirect effect was found through double mediation, with the difference in MRST from baseline to after stimulation and from baseline to after criticism as our two mediators. The larger the decrease of criticism induced MRST after real tDCS, the higher the level of actual self-esteem. Our results show that tDCS can influence cognitive processes such as rumination, and subsequently self-esteem, but only after the activation of negative self-schemas. Rumination and negative self-esteem characterize different forms of psychopathology, and these data expand our knowledge of the role of the prefrontal cortex in controlling these self-referential processes, and the mechanisms of action of tDCS. Copyright © 2017 Elsevier Ltd. All rights reserved.

Design and validation of a critical pathway for hospital management of patients with severe traumatic brain injury.

PubMed

Espinosa-Aguilar, Amilcar; Reyes-Morales, Hortensia; Huerta-Posada, Carlos E; de León, Itzcoatl Limón-Pérez; López-López, Fernando; Mejía-Hernández, Margarita; Mondragón-Martínez, María A; Calderón-Téllez, Ligia M; Amezcua-Cuevas, Rosa L; Rebollar-González, Jorge A

2008-05-01

Critical pathways for the management of patients with severe traumatic brain injury (STBI) may contribute to reducing the incidence of hospital complications, length of hospitalization stay, and cost of care. Such pathways have previously been developed for departments with significant resource availability. In Mexico, STBI is the most important cause of complications and length of stay in neurotrauma services at public hospitals. Although current treatment is designed basically in accordance with the Brain Trauma Foundation guidelines, shortfalls in the availability of local resources make it difficult to comply with these standards, and no critical pathway is available that accords with the resources of public hospitals. The purpose of the present study was to design and to validate a critical pathway for managing STBI patients that would be suitable for implementation in neurotrauma departments of middle-income level countries. The study comprised two phases: design (through literature review and design plan) and validation (content, construct, and appearance) of the critical pathway. The validated critical pathway for managing STBI patients entails four sequential subprocesses summarizing the hospital's care procedures, and includes three components: (1) nodes and criteria (in some cases, indicators are also included); (2) health team members in charge of the patient; (3) maximum estimated time for compliance with recommendations. This validated critical pathway is based on the current scientific evidence and accords with the availability of resources of middle-income countries.

Nursing care plans versus concept maps in the enhancement of critical thinking skills in nursing students enrolled in a baccalaureate nursing program.

PubMed

Sinatra-Wilhelm, Tina

2012-01-01

Appropriate and effective critical thinking and problem solving is necessary for all nurses in order to make complex decisions that improve patient outcomes, safety, and quality of nursing care. With the current emphasis on quality improvement, critical thinking ability is a noteworthy concern within the nursing profession. An in-depth review of literature related to critical thinking was performed. The use of nursing care plans and concept mapping to improve critical thinking skills was among the recommendations identified. This study compares the use of nursing care plans and concept mapping as a teaching strategy for the enhancement of critical thinking skills in baccalaureate level nursing students. The California Critical Thinking Skills Test was used as a method of comparison and evaluation. Results indicate that concept mapping enhances critical thinking skills in baccalaureate nursing students.

Flux pinning characteristics in cylindrical ingot niobium used in superconducting radio frequency cavity fabrication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dhavale Ashavai, Pashupati Dhakal, Anatolii A Polyanskii, Gianluigi Ciovati

We present the results of from DC magnetization and penetration depth measurements of cylindrical bulk large-grain (LG) and fine-grain (FG) niobium samples used for the fabrication of superconducting radio frequency (SRF) cavities. The surface treatment consisted of electropolishing and low temperature baking as they are typically applied to SRF cavities. The magnetization data were fitted using a modified critical state model. The critical current density Jc and pinning force Fp are calculated from the magnetization data and their temperature dependence and field dependence are presented. The LG samples have lower critical current density and pinning force density compared to FGmore » samples which implies a lower flux trapping efficiency. This effect may explain the lower values of residual resistance often observed in LG cavities than FG cavities.« less

Critical current density and vortex pinning in tetragonal FeS 1 ₋ x Se x ( x = 0 , 0.06 )

DOE PAGES

Wang, Aifeng; Wu, Lijun; Ivanovski, V. N.; ...

2016-09-07

Here we report critical current density (J c) in tetragonal FeS single crystals, similar to iron-based superconductors with much higher superconducting critical temperatures (T c). The J c is enhanced three times by 6% Se doping. We observe scaling of the normalized vortex pinning force as a function of reduced field at all temperatures. Vortex pinning in FeS and FeS 0.94Se 0.06 shows contribution of core-normal surfacelike pinning. Lastly, reduced temperature dependence of J c indicates that dominant interaction of vortex cores and pinning centers is via scattering of charge carriers with reduced mean free path (δl), in contrast tomore » K xFe 2₋ySe 2 where spatial variations in T c (δT c) prevails.« less

Bootstrap current in a tokamak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kessel, C.E.

1994-03-01

The bootstrap current in a tokamak is examined by implementing the Hirshman-Sigmar model and comparing the predicted current profiles with those from two popular approximations. The dependences of the bootstrap current profile on the plasma properties are illustrated. The implications for steady state tokamaks are presented through two constraints; the pressure profile must be peaked and {beta}{sub p} must be kept below a critical value.

Voltage-ampere characteristics of YBCO coated conductor under inhomogeneous oscillating magnetic field

NASA Astrophysics Data System (ADS)

Geng, J.; Shen, B.; Li, C.; Zhang, H.; Matsuda, K.; Li, J.; Zhang, X.; Coombs, T. A.

2016-06-01

Direct current carrying type II superconductors present a dynamic resistance when subjected to an oscillating magnetic field perpendicular to the current direction. If a superconductor is under a homogeneous field with high magnitude, the dynamic resistance value is nearly independent of transport current. Hoffmann and coworkers [Hoffmann et al., IEEE Trans. Appl. Supercond. 21, 1628 (2011)] discovered, however, flux pumping effect when a superconducting tape is under an inhomogeneous field orthogonal to the tape surface generated by rotating magnets. Following their work, we report the whole Voltage-Ampere (V-I) curves of an YBCO coated conductor under permanent magnets rotating with different frequencies and directions. We discovered that the two curves under opposite rotating directions differ from each other constantly when the transport current is less than the critical current, whereas the difference gradually reduces after the transport current exceeds the critical value. We also find that for different field frequencies, the difference between the two curves decreases faster with lower field frequency. The result indicates that the transport loss is dependent on the relative direction of the transport current and field travelling, which is distinct from traditional dynamic resistance model. The work may be instructive for the design of superconducting motors.

Multifilamentary niobium tin magnet conductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larbalestier, D.C.; Madsen, P.E.; Lee, J.A.

1975-03-01

Practical magnet conductors of multifilamentary Nb$sub 3$Sn have been produced. Evaluation of these bronze route conductors is described. Conductors studied range from a 1369 filament all-bronze matrix conductor to 5143 and approximately 42,000 filament conductors, containing internal high purity copper protected by diffusion barriers. Filament sizes vary from approximately 3 to 8 $mu$m diameter. The effect of heat treatment conditions on critical current and transition temperature is presented and it is shown that overall critical current densities greater than those available in niobium titanium can now be produced in multifilamentary Nb$sub 3$Sn magnet conductor.

Effects of densification of precursor pellets on microstructures and critical current properties of YBCO melt-textured bulks

NASA Astrophysics Data System (ADS)

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.

Control over dark current densities and cutoff wavelengths of GaAs/AlGaAs QWIP grown by multi-wafer MBE reactor

NASA Astrophysics Data System (ADS)

Roodenko, K.; Choi, K. K.; Clark, K. P.; Fraser, E. D.; Vargason, K. W.; Kuo, J.-M.; Kao, Y.-C.; Pinsukanjana, P. R.

2016-09-01

Performance of quantum well infrared photodetector (QWIP) device parameters such as detector cutoff wavelength and the dark current density depend strongly on the quality and the control of the epitaxy material growth. In this work, we report on a methodology to precisely control these critical material parameters for long wavelength infrared (LWIR) GaAs/AlGaAs QWIP epi wafers grown by multi-wafer production Molecular beam epitaxy (MBE). Critical growth parameters such as quantum well (QW) thickness, AlGaAs composition and QW doping level are discussed.

Effects of the Variable Lorentz Force on the Critical Current in Anisotropic Superconducting Thin Films (Postprint)

DTIC Science & Technology

2007-06-01

Phys. Lett., vol. 87, p. 162505, 2005. [2] J. L. Macmanus-Driscoll, S. R. Foltyn, Q. X. Jia, H. Wang, A. Serquis, L. Civale, B. Maiorov, M. E. Hawley ...B. Maiorov, L. Civale, Y. Lin, M. E. Hawley , M. P. Maley, and D. E. Peterson, “Systematic enhancement of in-field critical current density with rare...16, p. 162 507–1, 2005. [15] H. Safar, J. Y. Coulter, M. P. Maley, S. R. Foltyn, P. N. Arendt, X. D. Wu, and J. O. Willis , “Anisotropy and Lorentz

A descriptive inquiry of the definitions of critical thinking and enhancers and barriers reported by nurses working in long-term care facilities.

PubMed

Raterink, Ginger

2008-09-01

Critical thinking has been an outcome of nursing education since the 1980s. There remains a lack of agreement on definitions, methods of teaching, and methods of evaluation among practicing nurses. This study asked practicing nurses to define critical thinking. It also asked nurses to describe what work-related factors enhanced or posed barriers to the use of critical thinking in practice. Elements of the definitions presented were found to be consistent with current nursing definitions of critical thinking. Enhancers and barriers overlapped and were found to be consistent among the nurses at all facilities studied, with implications for continuing education and staff development.

Critical periods and amblyopia.

PubMed

Daw, N W

1998-04-01

During the past 20 years, basic science has shown that there are different critical periods for different visual functions during the development of the visual system. Visual functions processed at higher anatomical levels within the system have a later critical period than functions processed at lower levels. This general principle suggests that treatments for amblyopia should be followed in a logical sequence, with treatment for each visual function to be started before its critical period is over. However, critical periods for some visual functions, such as stereopsis, are not yet fully determined, and the optimal treatment is, therefore, unknown. This article summarizes the current extent of our knowledge and points to the gaps that need to be filled.

Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

DTIC Science & Technology

2009-11-23

there are no plans to do so.’”5 Critics expressed concern about the implications of these policies for testing and new weapons. A statement by...opportunity to design and build new nuclear weapons, and abandon a ten-year-old moratorium on nuclear weapons testing.”6 Another critic felt that increased...cannot diagnose or remedy a problem in a warhead critical the U.S. nuclear deterrent without conducting a nuclear test.10 Similarly, a Statement of

Nuclear Weapons: Comprehensive Test Ban Treaty

DTIC Science & Technology

2007-11-30

itself, which has been done. Critics raised concerns about the implications of these policies for testing and new weapons. At present, Congress...CTBT in lieu of the current treaty.1 On October 24, Senator Jon Kyl delivered a speech critical of the CTBT and of Section 3122 in H.R. 1585, the FY2008...to do so.’”6 Critics expressed concern about the implications of these policies for testing and new weapons. A statement by Physicians for Social

Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

DTIC Science & Technology

2010-01-06

the future, but there are no plans to do so.’”5 Critics expressed concern about the implications of these policies for testing and new weapons. A...seek the opportunity to design and build new nuclear weapons, and abandon a ten-year-old moratorium on nuclear weapons testing.”6 Another critic felt...warhead critical the U.S. nuclear deterrent without conducting a nuclear test.10 Similarly, a Statement of Administration Policy on S. 1547, FY2008

V&V Within Reuse-Based Software Engineering

NASA Technical Reports Server (NTRS)

Addy, Edward A.

1996-01-01

Verification and Validation (V&V) is used to increase the level of assurance of critical software, particularly that of safety-critical and mission-critical software. V&V is a systems engineering discipline that evaluates the software in a systems context, and is currently applied during the development of a specific application system. In order to bring the effectiveness of V&V to bear within reuse-based software engineering, V&V must be incorporated within the domain engineering process.

Parametric Criticality Safety Calculations for Arrays of TRU Waste Containers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gough, Sean T.

The Nuclear Criticality Safety Division (NCSD) has performed criticality safety calculations for finite and infinite arrays of transuranic (TRU) waste containers. The results of these analyses may be applied in any technical area onsite (e.g., TA-54, TA-55, etc.), as long as the assumptions herein are met. These calculations are designed to update the existing reference calculations for waste arrays documented in Reference 1, in order to meet current guidance on calculational methodology.

Uptake of critical knowledge in nursing practice: lessons learned from a knowledge translation study.

PubMed

Anderson, Joan M; Browne, Annette J; Reimer-Kirkham, Sheryl; Lynam, M Judith; Rodney, Paddy; Varcoe, Colleen; Wong, Sabrina; Tan, Elsie; Smye, Victoria; McDonald, Heather; Baumbusch, Jennifer; Khan, Koushambhi Basu; Reimer, Joanne; Peltonen, Adrienne; Brar, Anureet

2010-09-01

This article is based on a knowledge translation (KT) study of the transition of patients from hospital to home. It focuses on the lessons learned about the challenges of translating research-derived critical knowledge in practice settings. The authors situate the article in current discourses about KT; discuss their understanding of the nature of critical knowledge; and present themes from their body of research, which comprises the knowledge that was translated. The findings have the potential to guide future KT research that focuses on the uptake of critical knowledge in nursing practice.

Critical values in hematology of 862 institutions in China.

PubMed

Ye, Y Y; Zhao, H J; Fei, Y; Wang, W; He, F L; Zhong, K; Yuan, S; Wang, Z G

2017-10-01

A national survey on critical values in hematology of China laboratories was conducted to determine the current practice and assess the quality indicators so as to obtain a quality improvement. Laboratories participating were asked to submit the general information, the practice of critical value reporting, and the status of timeliness of critical value reporting. A total of 862 laboratories submitted the results. The majority of participants have included white blood cell count, blood platelet count, hemoglobin, prothrombin time, and activated partial thromboplastin time in their critical value lists. Many sources are used for establishing a critical value policy, and some of the laboratories consult with clinicians. The unreported critical value rate, late critical value reporting rate, and clinically unacknowledged rate in China are relatively low, and the median of critical value reporting time is 8-9 minutes. There exists a wide variety for critical value reporting in hematology in China. Laboratories should establish a policy of critical value reporting suited for their own situations and consult with clinicians to set critical value lists. Critical values are generally reported in a timely manner in China, but some measures should be taken to further improve the timeliness of critical value reporting. © 2017 John Wiley & Sons Ltd.

Numerical study of the existence criterion for the reversed shear Alfven eigenmode in the presence of a parallel equilibrium current

NASA Astrophysics Data System (ADS)

Shahzad, M.; Rizvi, H.; Panwar, A.; Ryu, C. M.

2017-06-01

We have re-visited the existence criterion of the reverse shear Alfven eigenmodes (RSAEs) in the presence of the parallel equilibrium current by numerically solving the eigenvalue equation using a fast eigenvalue solver code KAES. The parallel equilibrium current can bring in the kink effect and is known to be strongly unfavorable for the RSAE. We have numerically estimated the critical value of the toroidicity factor Qtor in a circular tokamak plasma, above which RSAEs can exist, and compared it to the analytical one. The difference between the numerical and analytical critical values is small for low frequency RSAEs, but it increases as the frequency of the mode increases, becoming greater for higher poloidal harmonic modes.

Toward superconducting critical current by design

DOE PAGES

Sadovskyy, Ivan A.; Jia, Ying; Leroux, Maxime; ...

2016-03-31

The interaction of vortex matter with defects in applied superconductors directly determines their current carrying capacity. Defects range from chemically grown nanostructures and crystalline imperfections to the layered structure of the material itself. The vortex-defect interactions are non-additive in general, leading to complex dynamic behavior that has proven difficult to capture in analytical models. With recent rapid progress in computational powers, a new paradigm has emerged that aims at simulation assisted design of defect structures with predictable ‘critical-current-by-design’: analogous to the materials genome concept of predicting stable materials structures of interest. We demonstrate the feasibility of this paradigm by combiningmore » large-scale time-dependent Ginzburg-Landau numerical simulations with experiments on commercial high temperature superconductor (HTS) containing well-controlled correlated defects.« less

Connecting to Collections in Florida: Current Conditions and Critical Needs in Libraries, Archives, and Museums

ERIC Educational Resources Information Center

Jorgensen, Corinne; Marty, Paul F.; Braun, Kathy

2012-01-01

This article presents results from an IMLS-funded project to evaluate the current state of collections in Florida's libraries, archives, and museums, current practices to preserve and conserve these collections, and perceived needs to maintain and improve these collections for future generations. The survey, modeled after the Heritage Health Index…

Crystallization screening: the influence of history on current practice.

PubMed

Luft, Joseph R; Newman, Janet; Snell, Edward H

2014-07-01

While crystallization historically predates crystallography, it is a critical step for the crystallographic process. The rich history of crystallization and how that history influences current practices is described. The tremendous impact of crystallization screens on the field is discussed.

Stable superconducting magnet. [high current levels below critical temperature

NASA Technical Reports Server (NTRS)

Boom, R. W. (Inventor)

1967-01-01

Operation of a superconducting magnet is considered. A method is described for; (1) obtaining a relatively high current in a superconducting magnet positioned in a bath of a gas refrigerant; (2) operating a superconducting magnet at a relatively high current level without training; and (3) operating a superconducting magnet containing a plurality of turns of a niobium zirconium wire at a relatively high current level without training.

The Rhetoric of Issue Advertising: A Rationale, a Case Study, a Critical Perspective--And More.

ERIC Educational Resources Information Center

Heath, Robert L.

1988-01-01

Supports the use of issue advertising. Argues that speech communication scholars can facilitate the responsible and effective use of issue ads. Reviews critics and proponents of issue advertising. Develops a rationale to guide the practice of issue advertising. Examines issue advertising in the current pro-nuclear campaign. (MS)

How Do Virtual World Experiences Bring about Learning? A Critical Review of Theories

ERIC Educational Resources Information Center

Loke, Swee-Kin

2015-01-01

While students do learn real-world knowledge and skills in virtual worlds, educators have yet to adequately theorise how students' virtual world experiences bring about this learning. This paper critically reviewed theories currently used to underpin empirical work in virtual worlds for education. In particular, it evaluated how applicable these…

Depression as a Mediator in the Relationship between Perceived Familial Criticism and College Adaptation

ERIC Educational Resources Information Center

Puff, Jayme; Kolomeyer, Ellen; McSwiggan, Meagan; Pearte, Catherine; Lauer, Brea-Anne; Renk, Kimberly

2016-01-01

Objective: This study examined relationships among emerging adults' perceived familial criticism, their depressive symptoms, and their college adaptation. Participants: The current study examined the responses of 412 emerging adults (300 females and 112 males) who were college students at a large southeastern university. The majority of these…

Teacher Prep 3.0: A Vision for Teacher Education to Impact Social Transformation

ERIC Educational Resources Information Center

Kretchmar, Kerry; Zeichner, Ken

2016-01-01

Teacher education in the USA is composed of both defenders and critics of the current system of teacher preparation. Some critics of college and university-based teacher education who describe themselves as "reformers" have referred to the non-university programmes as "teacher preparation 2.0" in order to emphasise the…

Critical Pedagogy and Empowering in Teacher Education in Venezuela.

ERIC Educational Resources Information Center

Chacon, Carmen T.; Alvarez, Luisa Cristina

This paper addresses the issue of the relationship between critical pedagogy and English as a foreign language (EFL) in Venezuela. Teacher-researchers have come to see the issues confronting nonnative educators in ELT as a more important issue than in previous years. They are particularly concerned about the current situation in Venezuela,…

A novel Fusarium species causes a canker disease of the critically endangered conifer, Torreya taxifolia

USDA-ARS?s Scientific Manuscript database

A canker disease of Florida torreya (Torreya taxifolia), here designated CDFT, has been implicated in the decline of this critically endangered species in its native range of northern Florida and southeastern Georgia. In our current surveys of eight Florida torreya sites, cankers were present on all...

Sexuality and Sexual Identity: Critical Possibilities for Teaching Dance Appreciation and Dance History

ERIC Educational Resources Information Center

Dils, Ann

2004-01-01

The intersections of dance and sexuality and sexual identity are part of the critical discourse important to teaching dance appreciation and dance history. This essay presents aspects of my teaching practice, informed by current writings in queer studies, dance studies, education, and sociology. Awareness of potential classroom diversity helps…

Career Education Programming in Three Diverse High Schools: A Critical Psychology--Case Study Research Approach

ERIC Educational Resources Information Center

Ali, Saba Rasheed; Yang, Ling-Yan; Button, Christopher J.; McCoy, Thomasin T. H.

2012-01-01

From a critical psychology perspective, Prilleltensky and Nelson advocate for research that has explicit focus on social change and can allow for full participation and empowerment of those under study. The current article describes the collaborative development, implementation, and evaluation of a career education program within three ethnically…

Setting the Mood for Critical Thinking in the Classroom

ERIC Educational Resources Information Center

Lewine, Rich; Sommers, Alison; Waford, Rachel; Robertson, Catherine

2015-01-01

Most current efforts to enhance critical thinking focus on skills practice and training. The empirical research from the fields of cognition and affect sciences suggest that positive mood, even when transiently induced, can have beneficial effects on cognitive flexibility and problem solving. We undertook this study to test this hypothesis in a…

Critical Pedagogy, Rituals of Distinction, and True Professionalism

ERIC Educational Resources Information Center

Nodoushan, Mohammad Ali Salmani; Pashapour, Arezou

2016-01-01

The current study sought to critically address the practice of rituals of distinction in nation-wide educational milieus to see if such practices can produce generations of underdeveloped and deprived learners. Data were collected over a course of two years from North Korea, Pakistan, Zimbabwe, Venezuela, and Somalia. A total of 419 teachers,…

An Evaluation of Critical Thinking Competencies in Business Settings

ERIC Educational Resources Information Center

Dwyer, Christopher P.; Boswell, Amy; Elliott, Mark A.

2015-01-01

Although critical thinking (CT) skills are usually considered as domain general (Gabbenesch, 2006; Halpern, 2003), CT ability may benefit from expertise knowledge and skill. The current study examined both general CT ability and CT ability related to business scenarios for individuals (a) expert in business, (b) novice in business, and (c) with no…

The Relationships between Critical Thinking Skills and Learning Styles of Gifted Students

ERIC Educational Resources Information Center

Dilekli, Yalçin

2017-01-01

The current study investigates the relationship between critical thinking skills and learning styles of mentally gifted students. The participants were 225 gifted students in Turkey attending Science and Art Centres which are after-school activity centers for mentally gifted students. Participants were 9-15 years old and were attending secondary…

The Impact of a Capstone Farm Management Course on Critical Thinking Abilities

ERIC Educational Resources Information Center

Perry, Dustin K.; Paulsen, Thomas H.; Retallick, Michael S.

2015-01-01

Current research demonstrates a need to explore the effects of specific course designs or directed activities on higher education students' critical thinking abilities. Specifically, such research on the effect of an experiential learning-based capstone course is limited. All students (N = 54) enrolled in a capstone farm management course…

Social Studies--The Next Generation: Re-Searching in the Postmodern. Counterpoints, Studies in the Postmodern Theory of Education Volume 272

ERIC Educational Resources Information Center

Segall, Avner, Ed.; Heilman, Elizabeth E., Ed.; Cherryholmes, Cleo H., Ed.

2006-01-01

This book broadens the imagination within social studies education by highlighting current, cutting-edge scholarship incorporating critical discourses. Drawing on postmodern, poststructural, postcolonial, and feminist theories often borrowed from cultural studies, curriculum theory, critical geography, women's studies, and queer studies, the…

Investigating Students' Negotiation of Religious Faiths in ELT Contexts: A Critical Spiritual Pedagogy Perspective

ERIC Educational Resources Information Center

Mambu, Joseph Ernest

2016-01-01

Based on a larger case study project at an English language teacher education program in Indonesia, this article demonstrates how Christian and non-Christian students negotiate their religious faiths in English-language-teaching (ELT) settings. In view of the critical spiritual pedagogy perspective, the current study defies dichotomizing religious…

Critical Features Predicting Sustained Implementation of School-Wide Positive Behavioral Interventions and Supports

ERIC Educational Resources Information Center

Mathews, Susanna; McIntosh, Kent; Frank, Jennifer L.; May, Seth L.

2014-01-01

The current study explored the extent to which a common measure of perceived implementation of critical features of Positive Behavioral Interventions and Supports (PBIS) predicted fidelity of implementation 3 years later. Respondents included school personnel from 261 schools across the United States implementing PBIS. School teams completed the…

Agency, Socialization, and Support: A Critical Review of Doctoral Student Attrition

ERIC Educational Resources Information Center

Rigler, Kenneth L., Jr.; Bowlin, Linda K.; Sweat, Karen; Watts, Stephen; Throne, Robin

2017-01-01

Almost universally, residential doctoral programs have reported attrition rates of up to 50% for face-to-face programs and 50-70% for online doctoral programs. The purpose of this critical review was to explore current literature for doctoral attrition and persistence to explore reasons and attributes for improved persistence to completion. We…

Critical Pedagogy and Assessment in Higher Education: The Ideal of "Authenticity" in Learning

ERIC Educational Resources Information Center

Serrano, Maria Martinez; O'Brien, Mark; Roberts, Krystal; Whyte, David

2018-01-01

Current forms of marketisation in university systems create pressures towards purely ends-focused expectations among students and have implications for learning and assessment processes. The potential harm that these trends have on "learning" should be resisted by educators and students alike. Critical Pedagogy approaches offer one way…

Critical Race Theory-Social Constructivist Bricolage: A Health-Promoting Schools Research Methodology

ERIC Educational Resources Information Center

Nyika, Lawrence; Murray-Orr, Anne

2017-01-01

While the current literature recognises the capacity of diverse methodologies to provide informative understandings of health-promoting schools (HPS), there is a paucity of examples to show how different research strategies can be used. We address this knowledge gap by examining the significance of a critical race theory-social constructivist…

International Organisations and the Evaluation of Education Systems: A Critical Comparative Analysis

ERIC Educational Resources Information Center

Neves, Claudia

2008-01-01

This article seeks to develop research involving a macro-level critical comparative analysis of reference documents produced by international organisations (UNDP, OECD, UNESCO, the World Bank and the European Union) which guide world education policy decisions. The primary objective was to consider the key guidelines currently defined for…

Inclusive Education in Sweden? A Critical Analysis

ERIC Educational Resources Information Center

Goransson, Kerstin; Nilholm, Claes; Karlsson, Kristina

2011-01-01

When it comes to pupils in need of special support and pupils with disabilities, Sweden's compulsory school system is sometimes considered a one-track system. This article analyses and critically discusses current policy and practices at various levels of Sweden's compulsory school system for these pupils. The analysis traces three themes at the…

Reflecting on Social Emotional Learning: A Critical Perspective on Trends in the United States

ERIC Educational Resources Information Center

Hoffman, Diane M.

2009-01-01

This critical cultural analysis of trends in the field of social emotional learning (SEL) in the United States considers how ideas concerning emotional skills and competencies have informed programmatic discourse. While currently stressing links between SEL and academic achievement, program literature also places emphasis on ideals of caring,…

Promoting Critical Awareness in the Initial Training of Preschool Teachers in Greece: Resistance and Perspectives

ERIC Educational Resources Information Center

Kourti, Evangelia; Androussou, Alexandra

2013-01-01

This article focuses on the development of future preschool teachers' critical awareness through the introduction of two "new" subjects--intercultural education and media education--in the curriculum of an early childhood department in Greece. The current social and political context, the structure of preschool teachers' training in…

Toward Improving Research in Social Studies Education. SSEC Monograph Series.

ERIC Educational Resources Information Center

Fraenkel, Jack R.; Wallen, Norman E.

Social studies research has been criticized for sampling bias, inappropriate methodologies, incorrect or inappropriate use of statistics, weak or ill-defined treatments, and lack of replication and/or longitudinal follow-up. In an effort to ascertain whether past criticisms were true of current research as well, a review was conducted of 118…

Listening to "Car Talk" and Learning Liberal Arts

ERIC Educational Resources Information Center

Goldstein, Warren

2004-01-01

In this article, Warren Goldstein, himself a college professor addresses a pair of radio talk show hosts, Tom and Ray, and their views on current topics such as environmental issues, cars, relationships between men and women, and specifically their criticisms of liberal arts programs. Tom and Ray have been critical of liberal arts because they…

Researching Students with Disabilities: The Importance of Critical Perspectives

ERIC Educational Resources Information Center

Vaccaro, Annemarie; Kimball, Ezekiel W.; Wells, Ryan S.; Ostiguy, Benjamin J.

2014-01-01

In this chapter, the authors critically review the current state of quantitative research on college students with disabilities and examine the exclusion of this marginalized population from much of our research. They propose ways to conduct research that more fully accounts for this diverse and important college population. The authors argue that…

Utilizing Theatre of the Oppressed within Teacher Education to Create Emancipatory Teachers

ERIC Educational Resources Information Center

Desai, Shiv R.

2017-01-01

A key focus of teacher preparation should be critical self-reflection, especially given the current context of market-driven school reform, which often leads to school closings, increases school segregation, and devastates local communities. The question, then, becomes how best to guide critical self-reflection for preservice teachers so that they…

"Media Mediators": Advocating an Alternate Paradigm for Critical Adult Education ICT Policy

ERIC Educational Resources Information Center

Remtulla, Karim A.

2010-01-01

This article explores the efficacy of current education program approaches to prepare instructors to achieve critical thinking and active learning from their students by integrating ICTs with traditional adult education practices. An argument is put forward that the increasing presence and influence of ICTs in education necessitates a paradigmatic…

76 FR 10055 - Changes to the Public Housing Assessment System (PHAS): Physical Condition Scoring Notice

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-23

... Weights and Criticality Levels, and Dictionary of Deficiency Definitions The Item Weights and Criticality Levels tables and the Dictionary of Deficiency Definitions, currently in use, were published as... Dictionary of Deficiency Definitions is found at http://www.hud.gov/offices/reac/pdf/pass_dict2.3.pdf . V...

How Critical Is Critical Infrastructure?

DTIC Science & Technology

2015-09-01

electrical power, telecommunications, transportation, petroleum liquid , or natural gas as shown in Figure 34 from the National Infrastructure Protection...Natural Gas Segment  Food and Agriculture Sector  Government facilities Sector  Healthcare and Public Health Sector  Information Technology...514 religious meeting places, 127 gas 69 “Current United States GDP,” 2015, http

Parents' Criticisms and Attributions about Their Adult Children with High Functioning Autism or Schizophrenia

ERIC Educational Resources Information Center

Wasserman, Stephanie; Weisman de Mamani, Amy; Mundy, Peter

2010-01-01

The current study examined the criticism component of expressed emotion (EE) and attributions in parents of adults diagnosed with schizophrenia/schizoaffective disorder (S/SA) or high functioning autism/Asperger's. Consistent with study hypotheses, parents of adults diagnosed with autism/Asperger's disorder exhibited lower levels of high…

The Politics of Time and Space in Japanese Adult Basic Education

ERIC Educational Resources Information Center

Jacobson, Erik

2015-01-01

This qualitative study examines critical pedagogy in Japanese adult basic education. The research focuses on what teachers and others think the current conditions are for education that deals with social justice. As part of this, the research looks at how critical pedagogy is conceptualized in this context. Participants in the study (literacy…

Critical Pedagogy: Constructing an Arch of Social Dreaming and a Doorway to Hope.

ERIC Educational Resources Information Center

McLaren, Peter

1991-01-01

Constructing an arch of social dreaming means developing a politics of difference that actively contests the devaluation of persons relegated as "others." In this connection, features of critical pedagogy, the role it plays in the struggle against current neoconservatism, and the importance of language are considered. (SLD)

Race, the Black Male, and Heterogeneous Racisms in Education

ERIC Educational Resources Information Center

Johnson-Bailey, Juanita; Ray, Nichole; Lasker-Scott, Tennille

2014-01-01

This chapter explores the effects of historical and current racism on the educational experiences of American Black males. The authors use critical race theory to illustrate how assumptions about culture and gender have subverted the egalitarian ideals of adult education. Teachers and students are urged to use critical reflection and open…

High field superconducting properties of Ba(Fe1-xCox)2As2 thin films

NASA Astrophysics Data System (ADS)

Hänisch, Jens; Iida, Kazumasa; Kurth, Fritz; Reich, Elke; Tarantini, Chiara; Jaroszynski, Jan; Förster, Tobias; Fuchs, Günther; Hühne, Ruben; Grinenko, Vadim; Schultz, Ludwig; Holzapfel, Bernhard

2015-11-01

In general, the critical current density, Jc, of type II superconductors and its anisotropy with respect to magnetic field orientation is determined by intrinsic and extrinsic properties. The Fe-based superconductors of the ‘122’ family with their moderate electronic anisotropies and high yet accessible critical fields (Hc2 and Hirr) are a good model system to study this interplay. In this paper, we explore the vortex matter of optimally Co-doped BaFe2As2 thin films with extended planar and c-axis correlated defects. The temperature and angular dependence of the upper critical field is well explained by a two-band model in the clean limit. The dirty band scenario, however, cannot be ruled out completely. Above the irreversibility field, the flux motion is thermally activated, where the activation energy U0 is going to zero at the extrapolated zero-kelvin Hirr value. The anisotropy of the critical current density Jc is both influenced by the Hc2 anisotropy (and therefore by multi-band effects) as well as the extended planar and columnar defects present in the sample.

Transcranial direct current stimulation (tDCS) to improve naming ability in post-stroke aphasia: A critical review.

PubMed

ALHarbi, Mohammed F; Armijo-Olivo, Susan; Kim, Esther S

2017-08-14

Transcranial Direct Current Stimulation (tDCS) is a non-invasive neuromodulation tool that can be used to influence cortical brain activity to induce measurable behavioral changes. Although there is growing evidence that tDCS combined with behavioural language therapy could boost language recovery in patients with post-stroke aphasia, there is great variability in patient characteristics, treatment protocols, and outcome measures in these studies that poses challenges for analyzing the evidence. The purpose of this study is to critically analyze the methodological rigor of the evidence regarding the use of tDCS for post-stroke anomia. This critical review was conducted by searching four databases (MEDLINE, EMBase, PsycINFO, and CINAHL). Nineteen studies fully met the inclusion criteria. Three critical appraisal tools and Robey and Schultz's (1998) five- phase model for conducting clinical outcome research were adopted to evaluate and analyze the current level of evidence. Methodological issues of the studies were also identified. The current level of evidence for using tDCS for anomia is at the pre-efficacy level with emerging evidence at the efficacy level. Lack of proper evaluation of carry-over effects in cross-over studies, lack of or unclear randomization, allocation concealment, and incomplete data handling were the main methodological issues that could threaten the validity of the tDCS for anomia studies. Several methodological issues have been identified in pre-efficacy studies that pose challenges in determining whether tDCS is a beneficial adjunct to behavioral aphasia therapy. Future studies need to improve the quality of the methods used to investigate the effect of tDCS for anomia. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigation of thick PLD-GdBCO and ZrO2 doped GdBCO coated conductors with high critical current on PLD-CeO2 capped IBAD-GZO substrate tapes

NASA Astrophysics Data System (ADS)

Takahashi, K.; Kobayashi, H.; Yamada, Y.; Ibi, A.; Fukushima, H.; Konishi, M.; Miyata, S.; Shiohara, Y.; Kato, T.; Hirayama, T.

2006-09-01

In order to increase the critical current, Ic, we have fabricated thick GdBa2Cu3O7-δ (GdBCO) coated conductors (CCs) by the pulsed laser deposition (PLD) method on PLD-CeO2/ion-beam assisted deposition (IBAD)-Gd2Zr2O7 (GZO)/hastelloy metal substrate tapes. The highest critical current value was 522 A cm-1 for a thickness of 3.6 µm in self-field at 77 K. It was found that a low volume fraction of a-axis orientated grains was obtained in the thick GdBCO CCs, compared to YBa2Cu3O7-δ (YBCO) CCs. Consequently, the GdBCO CCs showed higher critical current density (Jc) than YBCO CCs in all thicknesses from 0.2 to 3.6 µm. Furthermore, we have succeeded in improving Ic in a magnetic field by the introduction of artificial pinning centres using a 5 mol% ZrO2 doped GdBCO target. In the measurement of the Ic dependence on the magnetic field angle, θ, Ic was much improved, especially at 0°, i.e., with the magnetic field parallel to the c-axis. The Ic value at 3 T was 59.5 A cm-1 at 0° and it showed a minimum of 42.3 A cm-1 at 82° for 2.28 µm thick CC. The minimum value in the angular dependence of Ic at 3 T was about five times higher than that of YBCO CC and two times higher than that of pure GdBCO CC.

Development of a thick GdBCO and ZrO 2-doped GdBCO film with a high critical current on a PLD-CeO 2/IBAD-GZO metal substrate

NASA Astrophysics Data System (ADS)

Kinoshita, A.; Takahashi, K.; Kobayashi, H.; Yamada, Y.; Ibi, A.; Fukushima, H.; Konishi, M.; Miyata, S.; Shiohara, Y.; Kato, T.; Hirayama, T.

2007-10-01

In order to obtain a high critical current, Ic, we have fabricated a thick GdBa2Cu3O7-x (GdBCO) film by the pulsed laser deposition (PLD) method on a PLD-CeO2/ion-beam assisted deposition (IBAD)-Gd2Zr2O7 (GZO)/hastelloy metal substrate. The film of a 3.6 μm thickness exhibited the highest critical current of 522 A/cm at self-field and at 77 K. It was found that a low volume fraction of a-axis oriented grains was obtained in the thick GdBCO films, compared to YBa2Cu3O7-x (YBCO) films. The GdBCO films showed a higher critical current density (Jc), than YBCO films in all thicknesses from 0.2 to 3.6 μm. Furthermore, we have improved Ic in a magnetic field by the introduction of artificial pinning centers using a 5 mol% ZrO2-doped GdBCO target. In the measurement of angular dependence of Ic, which was much improved at 0°, the magnetic field was parallel to the c-axis. The Ic value at 3 T was 59.5 A/cm at 0° and showed a minimum of 42.3 A/cm at 82° for the film of a 2.3 μm thickness. The minimum value at 3 T in angular dependence of Ic was about five times higher than that of the YBCO film and two times higher than that of pure the GdBCO film.

Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

DTIC Science & Technology

2008-05-28

testing, and has no plans to test. It has reduced the time needed to conduct a nuclear test. Critics raised concerns about the implications of these...particularly as it is reduced, is reliable and safe. So he has not ruled out testing in the future, but there are no plans to do so.’”4 Critics ...Secretary of State, to Honorable Pete Domenici, United States Senate, June 25, 2007. a ten-year-old moratorium on nuclear weapons testing.”5 Another critic

Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

DTIC Science & Technology

2010-12-07

there are no plans to do so.’”4 Critics expressed concern about the implications of these policies for testing and new weapons. Physicians for...design and build new nuclear weapons, and abandon a ten-year-old moratorium on nuclear weapons testing.”5 Another critic felt that increased funding for...guarantees regarding the voluntary moratorium. We may find at some future time that we cannot diagnose or remedy a problem in a warhead critical the U.S

Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

DTIC Science & Technology

2009-01-28

safe. So he has not ruled out testing in the future, but there are no plans to do so.’”5 Critics expressed concern about the implications of these...nuclear weapons testing.”6 Another critic felt that increased funding for test readiness would in effect give prior approval for testing. In July 2002 a...moratorium. We may find at some future time that we cannot diagnose or remedy a problem in a warhead critical the U.S. nuclear deterrent without

Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

DTIC Science & Technology

2008-09-18

needed to conduct a nuclear test. Critics raised concerns about the implications of these policies for testing and new weapons. At present, Congress...as it is reduced, is reliable and safe. So he has not ruled out testing in the future, but there are no plans to do so.’”4 Critics expressed concern...ten-year-old moratorium on nuclear weapons testing.”5 Another critic felt that increased funding for test readiness would in effect give prior

Trigger Circuit.

DTIC Science & Technology

A wire of Nitinol can be stretched up to a given amount and will remain in this stretched state until heated to a critical temperature. When heated...circuit of this invention provides a current pulse for the required time period to heat the Nitinol wire to its critical temperature to thereby restore the...wire to its original length. The circuit includes a high power transistor which is gated on for a controlled time to provide the required power to heat the Nitinol wire to its critical temperature. (Author)

Critical threshold behavior for steady-state internal transport barriers in burning plasmas.

PubMed

García, J; Giruzzi, G; Artaud, J F; Basiuk, V; Decker, J; Imbeaux, F; Peysson, Y; Schneider, M

2008-06-27

Burning tokamak plasmas with internal transport barriers are investigated by means of integrated modeling simulations. The barrier sustainment in steady state, differently from the barrier formation process, is found to be characterized by a critical behavior, and the critical number of the phase transition is determined. Beyond a power threshold, alignment of self-generated and noninductively driven currents occurs and steady state becomes possible. This concept is applied to simulate a steady-state scenario within the specifications of the International Thermonuclear Experimental Reactor.

Testing critical point universality along the λ-line

NASA Astrophysics Data System (ADS)

Nissen, J. A.; Swanson, D. R.; Geng, Z. K.; Dohm, V.; Israelsson, U. E.; DiPirro, M. J.; Lipa, J. A.

1998-02-01

We are currently building a prototype for a new test of critical-point universality at the lambda transition in 4He, which is to be performed in microgravity conditions. The flight experiment will measure the second-sound velocity as a function of temperature at pressures from 1 to 30 bars in the region close to the lambda line. The critical exponents and other parameters characterizing the behavior of the superfluid density will be determined from the measurements. The microgravity measurements will be quite extensive, probably taking 30 days to complete. In addition to the superfluid density, some measurements of the specific heat will be made using the low-g simulator at the Jet Propulsion Laboratory. The results of the superfluid density and specific heat measurements will be used to compare the asymptotic exponents and other universal aspects of the superfluid density with the theoretical predictions currently established by renormalization group techniques.

Demagnetizing fields of crystallites and a method for measuring the thermodynamic fields of quasi-single-crystal and polycrystalline thin YBa{sub 2}Cu{sub 3}O{sub 7-x} disks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rostami, Kh. R.

The role of the demagnetizing fields of crystallites in HTSC samples is studied. An increase in the crystallite size is shown to suppress the intra-and intercrystalline critical currents of the sample in lower fields. The demagnetizing fields of crystallites are shown to be one of the main causes of the fact that the Bean model is invalid for HTSC samples. A method is proposed to measure the thermodynamic field of a superconductor; this method allows the first thermodynamic critical magnetic fields of the sample and its crystallites and 'subcrystallites' to be measured with a high accuracy. The first thermodynamic criticalmore » magnetic fields are used to estimate the critical current density J{sub c} of the sample, crystallites, and subcrystallites.« less

Flux pinning enhancement in thin films of Y3 Ba5 Cu8O18.5 + d

NASA Astrophysics Data System (ADS)

Aghabagheri, S.; Mohammadizadeh, M. R.; Kameli, P.; Salamati, H.

2018-06-01

YBa2Cu3O7 (Y123) and Y3Ba5Cu8O18 (Y358) thin films were deposited by pulsed laser deposition method. XRD analysis shows both films grow in c axis orientation. Resistivity versus temperature analysis shows superconducting transition temperature was about 91.2 K and 91.5 K and transition width for Y358 and Y123 films was about 0.6 K and 1.6 K, respectively. Analysis of the temperature dependence of the AC susceptibility near the transition temperature, employing Bean's critical state model, indicates that intergranular critical current density for Y358 films is more than twice of intergranular critical current density of Y123 films. Thus, flux pining is stronger in Y358 films. Weak links in the both samples is of superconductor-normal-superconductor (SNS) type irrespective of stoichiometry.

Carbon pollution increases health inequities: lessons in resilience from the most vulnerable.

PubMed

Ebi, Kristie L; Fawcett, Stephen B; Spiegel, Jerry; Tovalin, Horacio

2016-09-01

Climate change is a social justice as well as an environmental issue. The magnitude and pattern of changes in weather and climate variables are creating differential exposures, vulnerabilities, and health risks that increase stress on health systems while exacerbating existing and creating new health inequities. Examples from national and local health adaptation projects highlight that developing partnerships across sectors and levels are critical for building climate-resilient health systems and communities. Strengthening current and implementing new health interventions, such as using environmental information to develop early warning systems, can be effective in protecting the most vulnerable. However, not all projected risks of climate change can be avoided by climate policies and programs, so health system strengthening is also critical. Applying a health inequity lens can reduce current vulnerabilities while building resilience to longer-term climate change. Taking inequities into account is critical if societies are to effectively prepare for and manage the challenges ahead.

Instability of Insulators near Quantum Phase Transitions

NASA Astrophysics Data System (ADS)

Doron, A.; Tamir, I.; Levinson, T.; Ovadia, M.; Sacépé, B.; Shahar, D.

2017-12-01

Thin films of amorphous indium oxide undergo a magnetic field driven superconducting to insulator quantum phase transition. In the insulating phase, the current-voltage characteristics show large current discontinuities due to overheating of electrons. We show that the onset voltage for the discontinuities vanishes as we approach the quantum critical point. As a result, the insulating phase becomes unstable with respect to any applied voltage making it, at least experimentally, immeasurable. We emphasize that unlike previous reports of the absence of linear response near quantum phase transitions, in our system, the departure from equilibrium is discontinuous. Because the conditions for these discontinuities are satisfied in most insulators at low temperatures, and due to the decay of all characteristic energy scales near quantum phase transitions, we believe that this instability is general and should occur in various systems while approaching their quantum critical point. Accounting for this instability is crucial for determining the critical behavior of systems near the transition.

Vascular access in critical limb ischemia.

PubMed

Kang, Won Yu; Campia, Umberto; Ota, Hideaki; Didier, Romain J; Negi, Smita I; Kiramijyan, Sarkis; Koifman, Edward; Baker, Nevin C; Magalhaes, Marco A; Lipinski, Michael J; Escarcega, Ricardo O; Torguson, Rebecca; Waksman, Ron; Bernardo, Nelson L

2016-01-01

Currently, percutaneous endovascular intervention is considered a first line of therapy for treating patients with critical limb ischemia. As the result of remarkable development of techniques and technologies, percutaneous endovascular intervention has led to rates of limb salvage comparable to those achieved with bypass surgery, with fewer complications, even in the presence of lower rates of long-term patency. Currently, interventionalists have a multiplicity of access routes including smaller arteries, with both antegrade and retrograde approaches. Therefore, the choice of the optimal access site has become an integral part of the success of the percutaneous intervention. By understanding the technical aspects, as well as the advantages and limitations of each approach, the interventionalists can improve clinical outcomes in patients with severe peripheral arterial disease. This article reviews the access routes in critical limb ischemia, their advantages and disadvantages, and the clinical outcomes of each. Copyright © 2016 Elsevier Inc. All rights reserved.

Critical thinking in health professions education: summary and consensus statements of the Millennium Conference 2011.

PubMed

Huang, Grace C; Newman, Lori R; Schwartzstein, Richard M

2014-01-01

Critical thinking is central to the function of health care professionals. However, this topic is not explicitly taught or assessed within current programs, yet the need is greater than ever, in an era of information explosion, spiraling health care costs, and increased understanding about metacognition. To address the importance of teaching critical thinking in health professions education, the Shapiro Institute for Education and Research and the Josiah Macy Jr. Foundation jointly sponsored the Millennium Conference 2011 on Critical Thinking. Teams of physician and nurse educators were selected through an application process. Attendees proposed strategies for integrating principles of critical thinking more explicitly into health professions curricula. Working in interprofessional, multi-institutional groups, participants tackled questions about teaching, assessment, and faculty development. Deliberations were summarized into consensus statements. Educational leaders participated in a structured dialogue about the enhancement of critical thinking in health professions education and recommend strategies to teach critical thinking.

Engineering Surface Critical Behavior of (2 +1 )-Dimensional O(3) Quantum Critical Points

NASA Astrophysics Data System (ADS)

Ding, Chengxiang; Zhang, Long; Guo, Wenan

2018-06-01

Surface critical behavior (SCB) refers to the singularities of physical quantities on the surface at the bulk phase transition. It is closely related to and even richer than the bulk critical behavior. In this work, we show that three types of SCB universality are realized in the dimerized Heisenberg models at the (2 +1 )-dimensional O(3) quantum critical points by engineering the surface configurations. The ordinary transition happens if the surface is gapped in the bulk disordered phase, while the gapless surface state generally leads to the multicritical special transition, even though the latter is precluded in classical phase transitions because the surface is in the lower critical dimension. An extraordinary transition is induced by the ferrimagnetic order on the surface of the staggered Heisenberg model, in which the surface critical exponents violate the results of the scaling theory and thus seriously challenge our current understanding of extraordinary transitions.

Should we treat fever in critically ill patients? A summary of the current evidence from three randomized controlled trials

PubMed Central

Serpa, Ary; Pereira, Victor Galvão Moura; Colombo, Giancarlo; Scarin, Farah Christina de la Cruz; Pessoa, Camila Menezes Souza; Rocha, Leonardo Lima

2014-01-01

Fever is a nonspecific response to various types of infectious or non-infectious insult and its significance in disease remains an enigma. Our aim was to summarize the current evidence for the use of antipyretic therapy in critically ill patients. We performed systematic review and meta-analysis of publications from 1966 to 2013. The MEDLINE and CENTRAL databases were searched for studies on antipyresis in critically ill patients. The meta-analysis was limited to: randomized controlled trials; adult human critically ill patients; treatment with antipyretics in one arm versus placebo or non-treatment in another arm; and report of mortality data. The outcomes assessed were overall intensive care unit mortality, changes in temperature, intensive care unit length of stay, and hospital length of stay. Three randomized controlled trials, covering 320 participants, were included. Patients treated with antipyretic agents showed similar intensive care unit mortality (risk ratio 0.91, with 95% confidence interval 0.65-1.28) when compared with controls. The only difference observed was a greater decrease in temperature after 24 hours in patients treated with antipyretics (-1.70±0.40 versus - 0.56±0.25ºC; p=0.014). There is no difference in treating or not the fever in critically ill patients. PMID:25628209

Air, rail and road: Medical Guidelines for Employees with a History of Cerebrovascular Disease.

PubMed

Klein, Rebecca; Menon, Bijoy K; Rabi, Doreen; Stell, William; Hill, Michael D

2016-10-01

Background An acute medical condition following a previous stroke among those who operate trains, airplanes, and commercial vehicles can result in serious accidents. There are guidelines in place to assist physicians and employers in assessing the risks of returning to work after stroke but the extent and comprehensiveness across nations and among safety-critical occupations are not widely known. Methods Medical guidelines currently in place to regulate safety critical occupations including railway engineers, pilots and commercial vehicle drivers were systematically reviewed. Electronic and hand literature searches as well as review of grey literature for Canada, the USA, the UK, and Australia were conducted. Results There is no consistent set of guidelines that address the risk of a second catastrophic event after an initial cerebrovascular event in those employed in safety critical occupations in the four countries assessed. Some broad principles existed between the different countries and occupations but there was major variation in the approach to cerebrovascular disease and its impact on those working in safety-critical occupations. Conclusions A synthesis of current knowledge would assist in establishing risks of a catastrophic event in those who have already suffered from cerebrovascular illness. This will allow the creation of medical guidelines which could be applied to any safety critical occupation in any nation.

Treatment of hypophosphatemia in the intensive care unit: a review

PubMed Central

2010-01-01

Introduction Currently no evidence-based guideline exists for the approach to hypophosphatemia in critically ill patients. Methods We performed a narrative review of the medical literature to identify the incidence, symptoms, and treatment of hypophosphatemia in critically ill patients. Specifically, we searched for answers to the questions whether correction of hypophosphatemia is associated with improved outcome, and whether a certain treatment strategy is superior. Results Incidence: hypophosphatemia is frequently encountered in the intensive care unit; and critically ill patients are at increased risk for developing hypophosphatemia due to the presence of multiple causal factors. Symptoms: hypophosphatemia may lead to a multitude of symptoms, including cardiac and respiratory failure. Treatment: hypophosphatemia is generally corrected when it is symptomatic or severe. However, although multiple studies confirm the efficacy and safety of intravenous phosphate administration, it remains uncertain when and how to correct hypophosphatemia. Outcome: in some studies, hypophosphatemia was associated with higher mortality; a paucity of randomized controlled evidence exists for whether correction of hypophosphatemia improves the outcome in critically ill patients. Conclusions Additional studies addressing the current approach to hypophosphatemia in critically ill patients are required. Studies should focus on the association between hypophosphatemia and morbidity and/or mortality, as well as the effect of correction of this electrolyte disorder. PMID:20682049

[GEIPC-SEIMC (Study Group for Infections in the Critically Ill Patient of the Spanish Society for Infectious Diseases and Clinical Microbiology) and GTEI-SEMICYUC ( Working Group on Infectious Diseases of the Spanish Society of Intensive Medicine, Critical Care, and Coronary Units) recommendations for antibiotic treatment of gram-positive cocci infections in the critical patient].

PubMed

Astigarraga, P M Olaechea; Montero, J Garnacho; Cerrato, S Grau; Colomo, O Rodríguez; Martínez, M Palomar; Crespo, R Zaragoza; García-Paredes, P Muñoz; Cerdá, E Cerdá; Lerma, F Alvarez

2007-01-01

In recent years, an increment of infections caused by gram-positive cocci has been documented in nosocomial and hospital-acquired-infections. In diverse countries, a rapid development of resistance to common antibiotics against gram-positive cocci has been observed. This situation is exceptional in Spain but our country might be affected in the near future. New antimicrobials active against these multi-drug resistant pathogens are nowadays available. It is essential to improve our current knowledge about pharmacokinetic properties of traditional and new antimicrobials to maximize its effectiveness and to minimize toxicity. These issues are even more important in critically ill patients because inadequate empirical therapy is associated with therapeutic failure and a poor outcome. Experts representing two scientific societies (Grupo de estudio de Infecciones en el Paciente Crítico de la SEIMC and Grupo de trabajo de Enfermedades Infecciosas de la SEMICYUC) have elaborated a consensus document based on the current scientific evidence to summarize recommendations for the treatment of serious infections caused by gram-positive cocci in critically ill patients.

Free from Morality.

ERIC Educational Resources Information Center

Netopina, Svetlana

1996-01-01

Presents an example of current Russian cultural criticism. Articulates a diatribe against the current state of Russian culture and its influence on that country's youth. Condemns the influx of Western influences, sex and violence in the media, and the glorification of a drug culture through popular music. (MJP)

Crystallization screening: the influence of history on current practice

PubMed Central

Luft, Joseph R.; Newman, Janet; Snell, Edward H.

2014-01-01

While crystallization historically predates crystallography, it is a critical step for the crystallographic process. The rich history of crystallization and how that history influences current practices is described. The tremendous impact of crystallization screens on the field is discussed. PMID:25005076

Weak links in high critical temperature superconductors

NASA Astrophysics Data System (ADS)

Tafuri, Francesco; Kirtley, John R.

2005-11-01

The traditional distinction between tunnel and highly transmissive barriers does not currently hold for high critical temperature superconducting Josephson junctions, both because of complicated materials issues and the intrinsic properties of high temperature superconductors (HTS). An intermediate regime, typical of both artificial superconductor-barrier-superconductor structures and of grain boundaries, spans several orders of magnitude in the critical current density and specific resistivity. The physics taking place at HTS surfaces and interfaces is rich, primarily because of phenomena associated with d-wave order parameter (OP) symmetry. These phenomena include Andreev bound states, the presence of the second harmonic in the critical current versus phase relation, a doubly degenerate state, time reversal symmetry breaking and the possible presence of an imaginary component of the OP. All these effects are regulated by a series of transport mechanisms, whose rules of interplay and relative activation are unknown. Some transport mechanisms probably have common roots, which are not completely clear and possibly related to the intrinsic nature of high-TC superconductivity. The d-wave OP symmetry gives unique properties to HTS weak links, which do not have any analogy with systems based on other superconductors. Even if the HTS structures are not optimal, compared with low critical temperature superconductor Josephson junctions, the state of the art allows the realization of weak links with unexpectedly high quality quantum properties, which open interesting perspectives for the future. The observation of macroscopic quantum tunnelling and the qubit proposals represent significant achievements in this direction. In this review we attempt to encompass all the above aspects, attached to a solid experimental basis of junction concepts and basic properties, along with a flexible phenomenological background, which collects ideas on the Josephson effect in the presence of d-wave pairing for different types of barriers.

Diagnostic and prognostic biomarkers of sepsis in critical care.

PubMed

Kibe, Savitri; Adams, Kate; Barlow, Gavin

2011-04-01

Sepsis is a leading cause of mortality in critically ill patients. Delay in diagnosis and initiation of antibiotics have been shown to increase mortality in this cohort. However, differentiating sepsis from non-infectious triggers of the systemic inflammatory response syndrome (SIRS) is difficult, especially in critically ill patients who may have SIRS for other reasons. It is this conundrum that predominantly drives broad-spectrum antimicrobial use and the associated evolution of antibiotic resistance in critical care environments. It is perhaps unsurprising, therefore, that the search for a highly accurate biomarker of sepsis has become one of the holy grails of medicine. Procalcitonin (PCT) has emerged as the most studied and promising sepsis biomarker. For diagnostic and prognostic purposes in critical care, PCT is an advance on C-reactive protein and other traditional markers of sepsis, but is not accurate enough for clinicians to dispense with clinical judgement. There is stronger evidence, however, that measurement of PCT has a role in reducing the antibiotic exposure of critical care patients. For units intending to incorporate PCT assays into routine clinical practice, the cost-effectiveness of this is likely to depend on the pre-implementation length of an average antibiotic course and the subsequent impact of implementation on emerging antibiotic resistance. In most of the trials to date, the average baseline duration of the antibiotic course was longer than is currently standard practice in many UK critical care units. Many other biomarkers are currently being investigated. To be highly useful in clinical practice, it may be necessary to combine these with other novel biomarkers and/or traditional markers of sepsis.

Universal current-velocity relation of skyrmion motion in chiral magnets

NASA Astrophysics Data System (ADS)

Iwasaki, Junichi; Mochizuki, Masahito; Nagaosa, Naoto

2013-03-01

Current-driven motion of the magnetic domain wall requires large critical current density jc ~109 -1012 A/m2, at which the joule heating is a serious problem. The skyrmions recently discovered in chiral magnets, on the other hand, have much smaller critical current of jc ~105 -106 A/m2. We present a numerical simulation of the Landau-Lifshitz-Gilbert equation, which reveals a remarkably robust and universal current-velocity relation of the slyrmion motion driven by the spin transfer torque unaffected by either impurities or nonadiabatic effect in sharp contrast to the case of domain wall or spin helix (HL). Simulation results are analyzed using a theory based on Thiele's equation, and it is concluded that this surprising behavior is due to the Magnus force and flexible shape-deformation of individual skyrmions and skyrmion crystal (SkX), which enable them to avoid pinning centers and then weaken the net pinning force. Dynamical deformation of SkX leads to the fluctuation of Bragg peak with large amplitude, which can be detected by the recent neutron-scattering experiment.

Current induced magnetization switching in Co/Cu/Ni-Fe nanopillar with orange peel coupling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aravinthan, D.; Daniel, M.; Sabareesan, P.

The impact of orange peel coupling on spin current induced magnetization switching in a Co/Cu/Ni-Fe nanopillar device is investigated by solving the switching dynamics of magnetization of the free layer governed by the Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation. The value of the critical current required to initiate the magnetization switching is calculated analytically by solving the LLGS equation and verified the same through numerical analysis. Results of numerical simulation of the LLGS equation using Runge-Kutta fourth order procedure shows that the presence of orange peel coupling between the spacer and the ferromagnetic layers reduces the switching time of the nanopillar device frommore » 67 ps to 48 ps for an applied current density of 4 × 10{sup 12}Am{sup −2}. Also, the presence of orange peel coupling reduces the critical current required to initiate switching, and in this case, from 1.65 × 10{sup 12}Am{sup −2} to 1.39 × 10{sup 12}Am{sup −2}.« less

Onset of fast "ideal" tearing in thin current sheets: Dependence on the equilibrium current profile

NASA Astrophysics Data System (ADS)

Pucci, F.; Velli, M.; Tenerani, A.; Del Sarto, D.

2018-03-01

In this paper, we study the scaling relations for the triggering of the fast, or "ideal," tearing instability starting from equilibrium configurations relevant to astrophysical as well as laboratory plasmas that differ from the simple Harris current sheet configuration. We present the linear tearing instability analysis for equilibrium magnetic fields which (a) go to zero at the boundary of the domain and (b) contain a double current sheet system (the latter previously studied as a Cartesian proxy for the m = 1 kink mode in cylindrical plasmas). More generally, we discuss the critical aspect ratio scalings at which the growth rates become independent of the Lundquist number S, in terms of the dependence of the Δ' parameter on the wavenumber k of unstable modes. The scaling Δ'(k) with k at small k is found to categorize different equilibria broadly: the critical aspect ratios may be even smaller than L/a ˜ Sα with α = 1/3 originally found for the Harris current sheet, but there exists a general lower bound α ≥ 1/4.

Electromigration and morphological changes in Ag nanostructures

NASA Astrophysics Data System (ADS)

Chatterjee, A.; Bai, T.; Edler, F.; Tegenkamp, C.; Weide-Zaage, K.; Pfnür, H.

2018-02-01

Electromigration (EM) as a structuring tool was investigated in Ag nanowires (width 300 nm, thickness 25 nm) and partly in notched and bow-tie Ag structures on a Si(1 0 0) substrate in ultra-high vacuum using a four-tip scanning tunneling microscope in combination with a scanning electron microscope. From simulations of Ag nanowires we got estimates of temperature profiles, current density profiles, EM and thermal migration (TM) mass flux distributions within the nanowire induced by critical current densities of 108 A cm-2. At room temperature, the electron wind force at these current densities by far dominates over thermal diffusion, and is responsible for formation of voids at the cathode and hillocks at the anode side. For current densities that exceed the critical current densities necessary for EM, a new type of wire-like structure formation was found both at room temperature and at 100 K for notched and bow-tie structures. This suggests that the simultaneous action of EM and TM is structure forming, but with a very small influence of TM at low temperature.

Voltage current characteristics of type III superconductors

NASA Astrophysics Data System (ADS)

Dorofejev, G. L.; Imenitov, A. B.; Klimenko, E. Yu.

1980-06-01

An adequate description of voltage-current characteristics is important in order to understand the nature of high critical current for the electrodynamic construction of type-III superconductors and for commercial superconductor specification. Homogenious monofilament and multifilament Nb-Ti, Nb-Zr, Nb 3Sn wires were investigated in different ranges of magnetic field, temperature and current. The longitudinal electric field for homogenious wires may be described by E=J ρnexp- T c/T 0+ T/T 0+ B/B 0+ J/J 0, where To, Bo, Jo are the increasing parameters, which depend weakly on B and T, of the electric field. The shape of the voltage-current characteristics of multifilament wires, and the parameter's dependence on temperature and magnetic field may be explained qualitatively by the longitudinal heterogeneous nature of the filaments. A method of attaining the complete specification of the wire's electro-physical properties is proposed. It includes the traditional description of a critical surface (ie the surface corresponding to a certain conventional effective resistivity in T, B, J - space) and a description of any increasing parameter that depends on B and T.

A missing ethical competency? A review of critical reflection in health promotion.

PubMed

Tretheway, Rebecca; Taylor, Jane; O'Hara, Lily; Percival, Nikki

2015-12-01

There is increasing emphasis in the health promotion literature on the ethical imperative for the profession to move towards critical practice. A key challenge for health promotion is that critical practice appears both under-developed and under-practiced. This is evident in the omission of critical reflection from Australian and international competencies for health promotion practitioners. A narrative literature review was undertaken to explore the current use of critical reflection in health promotion. Critical reflection models relevant to health promotion were identified and critiqued. There was a dearth of literature on critical reflection within health promotion, despite recognition of its potential to support critical practice. The discipline of critical social work provided literature on the use, effect and outcome of critical reflection in practice. The interdisciplinary critical reflection model was identified as the model most applicable to health promotion. Underpinned by critical theory, this model emphasises both critical and ethical practice. Critical reflection is a core competency for health promotion practitioners to address the ethical imperative to move towards critical practice. There is a need to explore the application of a critical reflection model in health promotion to determine how it may support critical and ethical practice. So what? If health promotion is to meet its ethical responsibilities, then critical reflection needs to be articulated as a core health promotion competency and a model for its application in health promotion developed.

Exploring Education Culture by Employing Hofstede?s Cultural Dimensions to Evaluate the Effectiveness of the Current ERP Training Approach in Thailand

ERIC Educational Resources Information Center

Chayakonvikom, Monta; Fuangvut, Parin; Cannell, Stephen

2016-01-01

ERP training is a critical success factor in ERP implementation. The current ERP training was largely ineffective and caused user resistance and ERP implementation failure. The objective of this paper is to investigate whether the current ERP training approach can accommodate the cultural learning behaviors of end-users. Hofstede's cultural…

Current maternal depression moderates the relation between critical expressed emotion in mothers and depressive symptoms in their adolescent daughters.

PubMed

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.

Possibility of high temperature superconducting phases in PdH

NASA Astrophysics Data System (ADS)

Tripodi, Paolo; Di Gioacchino, Daniele; Borelli, Rodolfo; Vinko, Jenny Darja

2003-05-01

Possible new superconducting phases with a high critical transition temperature (Tc) have been found in stable palladium-hydrogen (PdHx) samples for stoichiometric ratio x=H/Pd⩾1, in addition to the well-known low critical transition temperature (0⩽Tc⩽9) when x is in the range (0.75⩽x⩽1.00). Possible new measured superconducting phases with critical temperature in the range 51⩽Tc⩽295 K occur. This Tc varies considerably with every milli part of x when x exceeds unit. A superconducting critical current density Jc⩾6.1×104 A cm-2 has been measured at 77 K with HDC=0 T.

Quantum criticality and universal scaling of strongly attractive spin-imbalanced Fermi gases in a one-dimensional harmonic trap

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin Xiangguo; Chen Shu; Guan Xiwen

2011-07-15

We investigate quantum criticality and universal scaling of strongly attractive Fermi gases confined in a one-dimensional harmonic trap. We demonstrate from the power-law scaling of the thermodynamic properties that current experiments on this system are capable of measuring universal features at quantum criticality, such as universal scaling and Tomonaga-Luttinger liquid physics. The results also provide insights on recent measurements of key features of the phase diagram of a spin-imbalanced atomic Fermi gas [Y. Liao et al., Nature (London) 467, 567 (2010)] and point to further study of quantum critical phenomena in ultracold atomic Fermi gases.

Spontaneous Polariton Currents in Periodic Lateral Chains.

PubMed

Nalitov, A V; Liew, T C H; Kavokin, A V; Altshuler, B L; Rubo, Y G

2017-08-11

We predict spontaneous generation of superfluid polariton currents in planar microcavities with lateral periodic modulation of both the potential and decay rate. A spontaneous breaking of spatial inversion symmetry of a polariton condensate emerges at a critical pumping, and the current direction is stochastically chosen. We analyze the stability of the current with respect to the fluctuations of the condensate. A peculiar spatial current domain structure emerges, where the current direction is switched at the domain walls, and the characteristic domain size and lifetime scale with the pumping power.

Advanced Critical Care Practitioners - Practical experience of implementing the Advanced Critical Care Practitioner Faculty of Intensive Care Medicine Curriculum in a London Critical Care Unit.

PubMed

Lee, Geraldine; Gilroy, Jo-Anne; Ritchie, Alistair; Grover, Vimal; Gull, Keetje; Gruber, Pascale

2018-05-01

With a chronic shortage of doctors in intensive care, alternative roles are being explored. One of these is the role of the Advanced Critical Care Practitioner. The Advanced Critical Care Practitioner Curriculum was developed by the Faculty of Intensive Care Medicine and is used to provide a structured programme of training. The Advanced Critical Care Practitioner programme consists of an academic and clinical component. This article outlines a practical approach of how the programme was developed and is currently being delivered at a single institution. This new advanced practice role offers opportunities to fill gaps in the medical workforce, improve continuity of patient care, provide mentoring and training for less experienced staff as well as offering a rewarding clinical role.

Flux Cloning in Josephson Transmission Lines

NASA Astrophysics Data System (ADS)

Gulevich, D. R.; Kusmartsev, F. V.

2006-07-01

We describe a novel effect related to the controlled birth of a single Josephson vortex. In this phenomenon, the vortex is created in a Josephson transmission line at a T-shaped junction. The “baby” vortex arises at the moment when a “mother” vortex propagating in the adjacent transmission line passes the T-shaped junction. In order to give birth to a new vortex, the mother vortex must have enough kinetic energy. Its motion can also be supported by an externally applied driving current. We determine the critical velocity and the critical driving current for the creation of the baby vortices and briefly discuss the potential applications of the found effect.

V/sub 3/Ga wire fabricated by the modified jelly roll technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gubser, D.U.; Francavilla, T.L.; Pande, C.S.

V/sub 3/Ga wire has been fabricated by the modified jelly roll technique for the first time. Critical current densities in magnetic fields to 22 T, critical magnetic fields, and superconducting transition temperatures are reported for this wire as a function of reaction temperature for forming the interfacial V/sub 3/Ga layer. Superconducting properties of the reacted wire are optimized for reaction temperatures between 550--580 /sup 0/C. With a reaction temperature of 580 /sup 0/C, the overall (noncopper) current density of the wire is over 10/sup 4/ amp/cm/sup 2/ at 19 T.

Fracture analysis of a transversely isotropic high temperature superconductor strip based on real fundamental solutions

NASA Astrophysics Data System (ADS)

Gao, Zhiwen; Zhou, Youhe

2015-04-01

Real fundamental solution for fracture problem of transversely isotropic high temperature superconductor (HTS) strip is obtained. The superconductor E-J constitutive law is characterized by the Bean model where the critical current density is independent of the flux density. Fracture analysis is performed by the methods of singular integral equations which are solved numerically by Gauss-Lobatto-Chybeshev (GSL) collocation method. To guarantee a satisfactory accuracy, the convergence behavior of the kernel function is investigated. Numerical results of fracture parameters are obtained and the effects of the geometric characteristics, applied magnetic field and critical current density on the stress intensity factors (SIF) are discussed.

Rapid doubling of the critical current of YBa 2Cu 3O 7-δ coated conductors for viable high-speed industrial processing

DOE PAGES

Leroux, M.; Kihlstrom, K. J.; Holleis, S.; ...

2015-11-09

Here, we demonstrate that 3.5-MeV oxygen irradiation can markedly enhance the in-field critical current of commercial second generation superconducting tapes with an exposure time of just 1 s per 0.8 cm 2. Furthermore we demonstrate how speed is now at the level required for an industrial reel-to-reel post-processing. The irradiation is made on production line samples through the protective silver coating and does not require any modification of the growth process. From TEM imaging, we identify small clusters as the main source of increased vortex pinning.

Method of forming an HTS article

DOEpatents

Bhattacharya, Raghu N.; Zhang, Xun; Selvamanickam, Venkat

2014-08-19

A method of forming a superconducting article includes providing a substrate tape, forming a superconducting layer overlying the substrate tape, and depositing a capping layer overlying the superconducting layer. The capping layer includes a noble metal and has a thickness not greater than about 1.0 micron. The method further includes electrodepositing a stabilizer layer overlying the capping layer using a solution that is non-reactive to the superconducting layer. The superconducting layer has an as-formed critical current I.sub.C(AF) and a post-stabilized critical current I.sub.C(PS). The I.sub.C(PS) is at least about 95% of the I.sub.C(AF).

Localized corrosion of 316L stainless steel with SiO2-CaO films obtained by means of sol-gel treatment.

PubMed

Vallet-Regí, M; Izquierdo-Barba, I; Gil, F J

2003-11-01

Sol-gel films on austenitic stainless steel (AISI 316L) polished wafer were prepared from sono-sols obtained from tetraethylorthosilane and hydrated calcium nitrate. However, pitting was observed in different places on the stainless steel surfaces. The corrosion resistance was evaluated by the polarization resistance in simulated body fluid environment at 37 degrees C. The critical current density, the passive current density, the corrosion potential, and the critical pitting potential were studied. The austenitic stainless steel 316L treated presents important electrochemical corrosion and consequently its application as endosseous implants is not possible. Copyright 2003 Wiley Periodicals, Inc.

Spontaneous fungal peritonitis: Epidemiology, current evidence and future prospective.

PubMed

Fiore, Marco; Leone, Sebastiano

2016-09-14

Spontaneous bacterial peritonitis is a complication of ascitic patients with end-stage liver disease (ESLD); spontaneous fungal peritonitis (SFP) is a complication of ESLD less known and described. ESLD is associated to immunodepression and the resulting increased susceptibility to infections. Recent perspectives of the management of the critically ill patient with ESLD do not specify the rate of isolation of fungi in critically ill patients, not even the antifungals used for the prophylaxis, neither optimal treatment. We reviewed, in order to focus the epidemiology, characteristics, and, considering the high mortality rate of SFP, the use of optimal empirical antifungal therapy the current literature.

NASA Formal Methods Workshop, 1990

NASA Technical Reports Server (NTRS)

Butler, Ricky W. (Compiler)

1990-01-01

The workshop brought together researchers involved in the NASA formal methods research effort for detailed technical interchange and provided a mechanism for interaction with representatives from the FAA and the aerospace industry. The workshop also included speakers from industry to debrief the formal methods researchers on the current state of practice in flight critical system design, verification, and certification. The goals were: define and characterize the verification problem for ultra-reliable life critical flight control systems and the current state of practice in industry today; determine the proper role of formal methods in addressing these problems, and assess the state of the art and recent progress toward applying formal methods to this area.

Critical current density and mechanism of vortex pinning in K xFe 2-ySe₂ doped with S

DOE PAGES

Lei, Hechang; Petrovic, C.

2011-08-15

We report the critical current density J c in K xFe 2-ySe 2-zS z crystals. The J c can be enhanced significantly with optimal S doping (z=0.99). For K 0.70(7)Fe 1.55(7)Se 1.01(2)S 0.99(2), the weak fishtail effect is found for H II c. The normalized vortex pinning forces follow the scaling law with a maximum position at 0.41 of the reduced magnetic field. These results demonstrate that the small size normal point defects dominate the vortex pinning mechanism.

Real-world aspects of the nuclear criticality safety program at the University of Tennessee-Knoxville

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bentley, C.L.; Dunn, M.E.; Goluoglu, S.

1996-12-31

The nuclear criticality safety (NCS) program at the University of Tennessee-Knoxville (UTK) emphasizes the {open_quotes}real world{close_quotes} in the NCS courses that are offered and also the NCS research that is conducted. Two NCS courses are offered at UTK. The first course is an introduction to the NCS field, which uses the text by Knief and includes an overview of criticality accidents that have actually happened, standards that are currently in use and being developed, and state-of-the-art computer methods and codes. The students learn the same codes, including both theory and application, that are used by most professionals in the NCSmore » field. Thus, if a student accepts a job offer in the NCS area after graduation, he or she is capable of doing productive NCS work the first day on the job. Subcritical limits, hand-calculation methods, current regulations [both U.S. Department of Energy (DOE) and U.S. Nuclear Regulatory Commission (NRC)] and current practices are also discussed in the introductory course. The second course emphasizes real world experience and is taught by five instructors with over 100 years of combined experience.« less

Comparative study of flux pinning, creep and critical currents between YBaCuO crystals with and without Y2BaCuO5 inclusions

NASA Technical Reports Server (NTRS)

Murakami, Masato; Gotoh, Satoshi; Fujimoto, Hiroyuki; Koshizuka, Naoki; Tanaka, Shoji

1991-01-01

In the Y-Ba-Cu-O system, YBa2Cu3O(x) phase is produced by the following peritectic reaction: Y2BaCuO5 + liquid yields 2YBa2Cu3O(x). Through the control of processing conditions and starting compositions, it becomes possible to fabricate large crystals containing fine Y2BaCuO5(211) inclusions. Such crystals exhibit Jc values exceeding 10000 A/sq cm at 77 K and 1T. Recently, researchers developed a novel process which can control the volume fraction of 211 inclusions. Elimination of 211 inclusions is also possible. In this study, researchers prepared YBaCuO crystals with and without 211 inclusions using the novel process, and compared flux pinning, flux creep and critical currents. Magnetic field dependence of Jc for YBaCuO crystals with and with 211 inclusions is shown. It is clear that fine 211 inclusions can contribute to flux pinning. It was also found that flux creep rate could be reduced by increasing flux pinning force. Critical current density estimates based on the conventional flux pinning theory were in good agreement with experimental results.

Intrinsic pinning and the critical current scaling of clean epitaxial Fe(Se,Te) thin films

NASA Astrophysics Data System (ADS)

Iida, Kazumasa; Hänisch, Jens; Reich, Elke; Kurth, Fritz; Hühne, Ruben; Schultz, Ludwig; Holzapfel, Bernhard; Ichinose, Ataru; Hanawa, Masafumi; Tsukada, Ichiro; Schulze, Michael; Aswartham, Saicharan; Wurmehl, Sabine; Büchner, Bernd

2013-03-01

We report on the transport properties of clean, epitaxial Fe(Se,Te) thin films prepared on Fe-buffered MgO (001) single crystalline substrates by pulsed laser deposition. Near Tc a steep slope of the upper critical field for H||ab was observed (74.1 T/K), leading to a very short out-of-plane coherence length, ξc(0), of 0.2 nm, yielding 2ξc(0)≈0.4nm. This value is shorter than the interlayer distance (0.605 nm) between the Fe-Se(Te) planes, indicative of modulation of the superconducting order parameter along the c axis. An inverse correlation between the power law exponent N of the electric field-current density(E-J) curve and the critical current density Jc has been observed at 4 K, when the orientation of H was close to the ab plane. These results prove the presence of intrinsic pinning in Fe(Se,Te). A successful scaling of the angular dependent Jc and the corresponding exponent N can be realized by the anisotropic Ginzburg Landau approach with appropriate Γ values 2˜3.5. The temperature dependence of Γ behaves almost identically to that of the penetration depth anisotropy.

Impact of shock waves on the conductive properties and structure of MgB2 tapes

NASA Astrophysics Data System (ADS)

Mikhailov, Boris P.; Mikhailova, Alexandra B.; Borovitskaya, Irina V.; Nikulin, Valerii Ya.; Peregudova, Elena N.; Polukhin, Sergei N.; Silin, Pavel V.

2017-10-01

This article presents data on shock waves effect on the structure and the critical current of superconducting MgB2 tapes. To generate shock waves, a plasma focus installation (PF) was used. The conductive characteristics of the superconducting tapes dependence on the intensity of the impact and the number of shock pulses were studied. A distinct pattern of change in critical currents in transversal and longitudinal magnetic fields in the range of 2-9 T is studied at a temperature of 4.2 K. The microstructure of the superconducting tape and chemical composition of its layer are studied in the original state and after the shock wave effect. Changes were found in a microstructure of layers of MgB2 (granulation, subdivision of grains and consolidation), which arose due to the shock-wave impact (SWI), are found. The possibility of increasing the critical current of tapes on 50-80 A in a transversal magnetic field of 2-3 T by means of SWI has been established. In a parallel magnetic field, the impact of the shock effect was essential in magnetic fields lower than 4 T.

Decontamination of Anthrax spores in critical infrastructure and critical assets.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boucher, Raymond M.; Crown, Kevin K.; Tucker, Mark David

2010-05-01

Decontamination of anthrax spores in critical infrastructure (e.g., subway systems, major airports) and critical assets (e.g., the interior of aircraft) can be challenging because effective decontaminants can damage materials. Current decontamination methods require the use of highly toxic and/or highly corrosive chemical solutions because bacterial spores are very difficult to kill. Bacterial spores such as Bacillus anthracis, the infectious agent of anthrax, are one of the most resistant forms of life and are several orders of magnitude more difficult to kill than their associated vegetative cells. Remediation of facilities and other spaces (e.g., subways, airports, and the interior of aircraft)more » contaminated with anthrax spores currently requires highly toxic and corrosive chemicals such as chlorine dioxide gas, vapor- phase hydrogen peroxide, or high-strength bleach, typically requiring complex deployment methods. We have developed a non-toxic, non-corrosive decontamination method to kill highly resistant bacterial spores in critical infrastructure and critical assets. A chemical solution that triggers the germination process in bacterial spores and causes those spores to rapidly and completely change to much less-resistant vegetative cells that can be easily killed. Vegetative cells are then exposed to mild chemicals (e.g., low concentrations of hydrogen peroxide, quaternary ammonium compounds, alcohols, aldehydes, etc.) or natural elements (e.g., heat, humidity, ultraviolet light, etc.) for complete and rapid kill. Our process employs a novel germination solution consisting of low-cost, non-toxic and non-corrosive chemicals. We are testing both direct surface application and aerosol delivery of the solutions. A key Homeland Security need is to develop the capability to rapidly recover from an attack utilizing biological warfare agents. This project will provide the capability to rapidly and safely decontaminate critical facilities and assets to return them to normal operations as quickly as possible, sparing significant economic damage by re-opening critical facilities more rapidly and safely. Facilities and assets contaminated with Bacillus anthracis (i.e., anthrax) spores can be decontaminated with mild chemicals as compared to the harsh chemicals currently needed. Both the 'germination' solution and the 'kill' solution are constructed of 'off-the-shelf,' inexpensive chemicals. The method can be utilized by directly spraying the solutions onto exposed surfaces or by application of the solutions as aerosols (i.e., small droplets), which can also reach hidden surfaces.« less

Current clinical nutrition practices in critically ill patients in Latin America: a multinational observational study.

PubMed

Vallejo, Karin Papapietro; Martínez, Carolina Méndez; Matos Adames, Alfredo A; Fuchs-Tarlovsky, Vanessa; Nogales, Guillermo Carlos Contreras; Paz, Roger Enrique Riofrio; Perman, Mario Ignacio; Correia, Maria Isabel Toulson Davisson; Waitzberg, Dan Linetzky

2017-08-25

Malnutrition in critically ill adults in the intensive care unit (ICU) is associated with a significantly elevated risk of mortality. Adequate nutrition therapy is crucial to optimise outcomes. Currently, there is a paucity of such data in Latin America. Our aims were to characterise current clinical nutrition practices in the ICU setting in Latin America and evaluate whether current practices meet caloric and protein requirements in critically ill patients receiving nutrition therapy. We conducted a cross-sectional, retrospective, observational study in eight Latin American countries (Argentina, Brazil, Chile, Colombia, Ecuador, Mexico, Panama, and Peru). Eligible patients were critically ill adults hospitalised in the ICU and receiving enteral nutrition (EN) and/or parenteral nutrition (PN) on the Screening Day and the previous day (day -1). Caloric and protein balance on day -1, nutritional status, and prescribed nutrition therapy were recorded. Multivariable logistic regression analysis was performed to identify independent predictors of reaching daily caloric and protein targets. The analysis included 1053 patients from 116 hospitals. Evaluation of nutritional status showed that 74.1% of patients had suspected/moderate or severe malnutrition according to the Subjective Global Assessment. Prescribed nutrition therapy included EN alone (79.9%), PN alone (9.4%), and EN + PN (10.7%). Caloric intake met >90% of the daily target in 59.7% of patients on day -1; a caloric deficit was present in 40.3%, with a mean (±SD) daily caloric deficit of -688.8 ± 455.2 kcal. Multivariable logistic regression analysis showed that combined administration of EN + PN was associated with a statistically significant increase in the probability of meeting >90% of daily caloric and protein targets compared with EN alone (odds ratio, 1.56; 95% confidence interval, 1.02-2.39; p = 0.038). In the ICU setting in Latin America, malnutrition was highly prevalent and caloric intake failed to meet targeted energy delivery in 40% of critically ill adults receiving nutrition therapy. Supplemental administration of PN was associated with improved energy and protein delivery; however, PN use was low. Collectively, these findings suggest an opportunity for more effective utilisation of supplemental PN in critically ill adults who fail to receive adequate nutrition from EN alone.

Effects of bending on the superconducting critical current density of monofilamentary Nb3Sn wires

NASA Astrophysics Data System (ADS)

Kaiho, K.; Luhman, T. S.; Suenaga, M.; Sampson, W. B.

1980-02-01

Variations in the superconducting current density Jc of the Nb3Sn wires upon bending were measured for a series of monofilamentary wires in which the ratio Rv of the matrix (Cu+Sn) to the core (Nb3Sn,Nb) was changed from 0 to 58. In most cases Jc was found to increase slightly until the bending strain exceeded a value of ɛirrB , beyond which it severely and irreversibly degraded. For wires with intermediate values of Rv (˜2 to 10), ɛirrB , calculated by geometrical considerations, was substantially lower than the measured value of the tensile strain ɛirrT which was required to irreversibly degrade the critical current. The influence of bending strains on Jc can qualitatively be described by considering residual prestrains in the matrix and the core.

The critical care air transport program.

PubMed

Beninati, William; Meyer, Michael T; Carter, Todd E

2008-07-01

The critical care air transport team program is a component of the U.S. Air Force Aeromedical Evacuation system. A critical care air transport team consists of a critical care physician, critical care nurse, and respiratory therapist along with the supplies and equipment to operate a portable intensive care unit within a cargo aircraft. This capability was developed to support rapidly mobile surgical teams with high capability for damage control resuscitation and limited capacity for postresuscitation care. The critical care air transport team permits rapid evacuation of stabilizing casualties to a higher level of care. The aeromedical environment presents important challenges for the delivery of critical care. All equipment must be tested for safety and effectiveness in this environment before use in flight. The team members must integrate the current standards of care with the limitation imposed by stresses of flight on their patient. The critical care air transport team capability has been used successfully in a range of settings from transport within the United States, to disaster response, to support of casualties in combat.

Decision Support for Renewal of Wastewater Collection and Water Distribution Systems

EPA Science Inventory

The objective of this study was to identify the current decision support methodologies, models and approaches being used for determining how to rehabilitate or replace underground utilities; identify the critical gaps of these current models through comparison with case history d...

36 CFR Appendix A to Part 1234 - Minimum Security Standards for Level III Federal Facilities

Code of Federal Regulations, 2013 CFR

2013-07-01

... construction projects should be reviewed if possible, to incorporate current technology and blast standards... critical systems (alarm systems, radio communications, computer facilities, etc.) Required. Occupant... all exterior windows (shatter protection) Recommended. Review current projects for blast standards...

Nonlinear AC susceptibility, surface and bulk shielding

NASA Astrophysics Data System (ADS)

van der Beek, C. J.; Indenbom, M. V.; D'Anna, G.; Benoit, W.

1996-02-01

We calculate the nonlinear AC response of a thin superconducting strip in perpendicular field, shielded by an edge current due to the geometrical barrier. A comparison with the results for infinite samples in parallel field, screened by a surface barrier, and with those for screening by a bulk current in the critical state, shows that the AC response due to a barrier has general features that are independent of geometry, and that are significantly different from those for screening by a bulk current in the critical state. By consequence, the nonlinear (global) AC susceptibility can be used to determine the origin of magnetic irreversibility. A comparison with experiments on a Bi 2Sr 2CaCu 2O 8+δ crystal shows that in this material, the low-frequency AC screening at high temperature is mainly due to the screening by an edge current, and that this is the unique source of the nonlinear magnetic response at temperatures above 40 K.

Self-organised criticality and 1/f noise in single-channel current of voltage-dependent anion channel

NASA Astrophysics Data System (ADS)

Banerjee, J.; Verma, M. K.; Manna, S.; Ghosh, S.

2006-02-01

Noise profile of Voltage Dependent Anion Channel (VDAC) is investigated in open channel state. Single-channel currents through VDAC from mitochondria of rat brain reconstituted into a planar lipid bilayer are recorded under different voltage clamped conditions across the membrane. Power spectrum analysis of current indicates power law noise of 1/f nature. Moreover, this 1/f nature of the open channel noise is seen throughout the range of applied membrane potential from -30 to +30 mV. It is being proposed that 1/f noise in open ion channel arises out of obstruction in the passage of ions across the membrane. The process is recognised as a phenomenon of self-organized criticality (SOC) like sandpile avalanche and other physical systems. Based on SOC it has been theoretically established that the system of ion channel follows power law noise as observed in our experiments. We also show that the first-time return probability of current fluctuations obeys a power law distribution.

Role of lead in electrochemical reaction of alloy 600, alloy 690, Ni, Cr, and Fe in water

NASA Astrophysics Data System (ADS)

Hwang, Seong Sik; Kim, Joung Soo; Kim, Ju Yup

2003-08-01

It has been reported that lead causes stress corrosion cracking (SCC) in the secondary side of steam generators (SG) in pressurized water reactors (PWR). The materials of SG tubings are alloy 600, alloy 690, or alloy 800, among which the main alloying elements are Ni, Cr, and Fe. The effect of lead on the electrochemical behaviors of alloy 600 and alloy 690 using an anodic polarization technique was evaluated. We also obtained polarization curves of pure Ni, Cr, and Fe in water containing lead. As the amount of lead in the solution increased, critical current densities and passive current densities of alloy 600 and alloy 690 increased, while the breakdown potential of the alloys decreased. Lead increased critical current density and the passive current of Cr in pH 4 and pH 10. The instability of passive film of steam generator tubings in water containing lead might arise from the instability of Cr passivity.

Simulation of the Vortex Dynamics in a Real Pinning Landscape of YBa 2 Cu 3 O 7 - δ Coated Conductors

DOE PAGES

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

2016-01-01

The ability of high-temperature superconductors (HTSs) to carry very large currents with almost no dissipation makes them irreplaceable for high-power applications. The development and further improvement of HTS-based cables require an in-depth understanding of the superconducting vortex dynamics in the presence of complex pinning landscapes. We present a critical current analysis of a real HTS sample in a magnetic field by combining state-of-the-art large-scale Ginzburg-Landau simulations with reconstructive three-dimensional scanning-transmission-electron-microscopy tomography of the pinning landscape in Dy-doped YBa 2Cu 3O 7-δ. This methodology provides a unique look at the vortex dynamics in the presence of a complex pinning landscape responsiblemore » for the high-current-carrying-capacity characteristic of commercial HTS wires. Finally, our method demonstrates very good functional and quantitative agreement of the critical current between simulation and experiment, providing a new predictive tool for HTS wire designs.« less

Monitoring the outcomes of interventions against Taenia solium: options and suggestions.

PubMed

Lightowlers, M W; Garcia, H H; Gauci, C G; Donadeu, M; Abela-Ridder, B

2016-03-01

There is an increasing interest in reducing the incidence of human neurocysticercosis, caused by infection with the larval stage of Taenia solium. Several intervention trials are currently assessing various options for control of T. solium transmission. A critical aspect of these trials will be the evaluation of whether the interventions have been successful. However, there is no consensus about the most appropriate or valuable methods that should be used. Here, we undertake a critical assessment of the diagnostic tests which are currently available for human T. solium taeniasis and human and porcine cysticercosis, as well as their suitability for evaluation of intervention trial outcomes. Suggestions are made about which of the measures that are available for evaluation of T. solium interventions would be most suitable, and which methodologies are the most appropriate given currently available technologies. Suggestions are also made in relation to the most urgent research needs in order to address deficiencies in current diagnostic methods. © 2015 The Authors. Parasite Immunology Published by John Wiley & Sons Ltd.

Simulation of the Vortex Dynamics in a Real Pinning Landscape of YBa 2 Cu 3 O 7 - δ Coated Conductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

The ability of high-temperature superconductors (HTSs) to carry very large currents with almost no dissipation makes them irreplaceable for high-power applications. The development and further improvement of HTS-based cables require an in-depth understanding of the superconducting vortex dynamics in the presence of complex pinning landscapes. We present a critical current analysis of a real HTS sample in a magnetic field by combining state-of-the-art large-scale Ginzburg-Landau simulations with reconstructive three-dimensional scanning-transmission-electron-microscopy tomography of the pinning landscape in Dy-doped YBa 2Cu 3O 7-δ. This methodology provides a unique look at the vortex dynamics in the presence of a complex pinning landscape responsiblemore » for the high-current-carrying-capacity characteristic of commercial HTS wires. Finally, our method demonstrates very good functional and quantitative agreement of the critical current between simulation and experiment, providing a new predictive tool for HTS wire designs.« less

Simulation of the Vortex Dynamics in a Real Pinning Landscape of YBa 2 Cu 3 O 7 - δ Coated Conductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

Tmore » he ability of high-temperature superconductors (HSs) to carry very large currents with almost no dissipation makes them irreplaceable for high-power applications. he development and further improvement of HS-based cables require an in-depth understanding of the superconducting vortex dynamics in the presence of complex pinning landscapes. Here, we present a critical current analysis of a real HS sample in a magnetic field by combining state-of-the-art large-scale Ginzburg-Landau simulations with reconstructive three-dimensional scanning-transmission-electron-microscopy tomography of the pinning landscape in Dy-doped YBa 2 Cu 3 O 7 - δ . his methodology provides a unique look at the vortex dynamics in the presence of a complex pinning landscape responsible for the high-current-carrying-capacity characteristic of commercial HS wires. Our method demonstrates very good functional and quantitative agreement of the critical current between simulation and experiment, providing a new predictive tool for HS wire designs.« less

Synthesis of zirconium oxynitride in air under DC electric fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morisaki, Nobuhiro; Tokunaga, Tomoharu; Sasaki, Katsuhiro

We synthesized zirconium oxynitride from yttria-stabilized zirconia (YSZ) in air by applying DC electric fields that produced a controlled electric current in the specimen. When YSZ was heated under an applied DC electric field, the electric current of the specimen steeply increased at a critical temperature, called a flash event, during flash sintering. By keeping the electric current of the specimen constant during the flash event and then holding the specimen at the critical temperature, YSZ was transformed into zirconium oxynitride under the optimal conditions of 50 V/cm, 500 mA, and 1000 °C. We confirmed that zirconium oxynitride formed using high-resolution transmission electronmore » microscopy, electron energy-loss spectroscopy, and energy-dispersive spectrometry. To convert oxides to nitrides, reducing conditions are necessary to form excess oxygen vacancies. Our technique produced the strong reducing conditions necessary to form nitrides from the oxides by delivering a controlled electric current to the specimen.« less

Promising critical current density characteristics of Ag-sheathed (Sr,Na)Fe2As2 tape

NASA Astrophysics Data System (ADS)

Suwa, Takahiro; Pyon, Sunseng; Tamegai, Tsuyoshi; Awaji, Satoshi

2018-06-01

We report the fabrication of (Sr,Na)Fe2As2 superconducting tapes by the powder-in-tube technique and their characteristics, including the transport critical current density J c at 4.2 K up to 140 kOe, the magnetic J c estimated from magnetic hysteresis curves, magneto-optical (MO) images, and scanning electron microscopy images. In a tape sintered at 875 °C for 1 h, the transport J c reaches 26 kA/cm2 at 4.2 K and 100 kOe for a field perpendicular to the tape surface. When the field is parallel to the tape surface, the magnetic J c exceeds the practical level of 100 kA/cm2 at 4.2 K below 25 kOe. Analysis of the MO images reveals clear current discontinuity lines in the core, indicating that the current flows homogeneously and the connections between grains are strong in the core.

What happens in Josephson junctions at high critical current densities

NASA Astrophysics Data System (ADS)

Massarotti, D.; Stornaiuolo, D.; Lucignano, P.; Caruso, R.; Galletti, L.; Montemurro, D.; Jouault, B.; Campagnano, G.; Arani, H. F.; Longobardi, L.; Parlato, L.; Pepe, G. P.; Rotoli, G.; Tagliacozzo, A.; Lombardi, F.; Tafuri, F.

2017-07-01

The impressive advances in material science and nanotechnology are more and more promoting the use of exotic barriers and/or superconductors, thus paving the way to new families of Josephson junctions. Semiconducting, ferromagnetic, topological insulator and graphene barriers are leading to unconventional and anomalous aspects of the Josephson coupling, which might be useful to respond to some issues on key problems of solid state physics. However, the complexity of the layout and of the competing physical processes occurring in the junctions is posing novel questions on the interpretation of their phenomenology. We classify some significant behaviors of hybrid and unconventional junctions in terms of their first imprinting, i.e., current-voltage curves, and propose a phenomenological approach to describe some features of junctions characterized by relatively high critical current densities Jc. Accurate arguments on the distribution of switching currents will provide quantitative criteria to understand physical processes occurring in high-Jc junctions. These notions are universal and apply to all kinds of junctions.

Comment on "Rabbit-Ears Hybrids, VSEPR Sterics, and Other Orbital Anachronisms": A Reply to a Criticism

ERIC Educational Resources Information Center

Hiberty, Philippe C.; Danovich, David; Shaik, Sason

2015-01-01

This commentary summarizes the authors' basic disagreements with the paper, "Rabbit-Ears, VSEPR Sterics, and Other Orbital Anachronisms," which criticizes the authors' usage of the hybrid orbitals for H[subscript 2]O in their book, "A Chemist's Guide to Valence Bond Theory" (Shaik and Hiberty, 2008). The current article shows…

Neoliberalism, Lifelong Learning, and the Homeplace: Problematizing the Boundaries of "Public" and "Private" to Explore Women's Learning Experiences

ERIC Educational Resources Information Center

Gouthro, Patricia A.

2009-01-01

This paper develops a critical feminist theoretical analysis of the significance of the homeplace in explaining the experiences of adult women learners. It argues that current discourses in lifelong learning are shaped by neoliberal influences that emphasize individualism, competition, and connections to the marketplace. Critical educators,…

U.S. Science Teaching and Learning of Evolution: A Critical Review of the Literature 2000-2014

ERIC Educational Resources Information Center

Glaze, Amanda L.; Goldston, M. Jenice

2015-01-01

This critical analysis examined research on evolution in the United States between the years 2000-2014, spanning early classroom implementation of the National Science Education Standards to current research findings. First, we sought to understand how the research literature published between 2000 and 2014 contributed to knowledge of evolution…

Universities and Regional Development: A Critical Assessment of Tensions and Contradictions. International Studies in Higher Education

ERIC Educational Resources Information Center

Pinheiro, Romulo, Ed.; Benneworth, Paul, Ed.; Jones, Glen A., Ed.

2012-01-01

Universities are under increasing pressure to help promote socio-economic growth in their local communities. However until now, no systematic, critical attention has been paid to the factors and mechanisms that currently make this process so daunting. In Universities and Regional Development, scholars from Europe, the Americas, Africa, and Asia…

Mastering Leadership Concepts through Utilizing Critical Thinking Strategies within Educational Administration Courses at Kuwait University

ERIC Educational Resources Information Center

Alqahtani, Abdulmuhsen Ayedh; Al-Enezi, Mutlaq M.

2012-01-01

The current study aims at exploring the students' perceptions of mastering leadership concepts and critical thinking strategies implemented by faculty members in the college of education at Kuwait University, and the impact of the later on former. The data was collected using a questionnaire on a sample consisting of 411 students representing…

Beyond Freedom of Speech and the Public Interest: The Relevance of Critical Legal Studies to Communications Policy.

ERIC Educational Resources Information Center

Streeter, Thomas

1990-01-01

Explores the implications of critical legal studies (CLS)--a new current in contemporary legal theory--for general discussions of freedom of speech and public interest. Applies CLS concepts to the conflict between broadcasters' and citizens' free speech rights as expressed in the contemporary Fairness Doctrine. Explores CLS's relevance to several…

A Critical Analysis of Western Perspectives on Families of Arab Descent

ERIC Educational Resources Information Center

Beitin, Ben K.; Allen, Katherine R.; Bekheet, Maureen

2010-01-01

Western research on families of Arab descent has increased in the current decade, compared to the previous 30 years. In this review of 256 empirical articles, through a critical postcolonial lens, domestic violence and family planning were the two most established areas of study. Generally, samples have come from a small group of countries such as…

Re-Envisioning Diversity in Higher Education: From Raising Awareness to Building Critical Consciousness among Faculty

ERIC Educational Resources Information Center

Stachowiak, Dana M.

2015-01-01

In this article, the author describes a disconnect between knowing "about" diversity and "understanding" diversity and recommends re-building the critical consciousness of faculty by turning the current discourse from a framework of diversity to a framework of social justice. As defined in the article, diversity is a call to be…

How Scientists Use Critical-Thinking Skills: Isolating Both Total RNA and Protein Using the Same Small Organ

ERIC Educational Resources Information Center

Porta, Angela R.; Dhawan, Puneet

2006-01-01

Undergraduate biology programs are currently undergoing reform to involve students in biomedical research. Engaging students in more active, hands-on experiments allows students to discover scientific principles for themselves, and to develop techniques of critical thinking and problem solving. This models the world of real scientific research,…

Integrating Cost Engineering and Project Management in a Junior Engineering Economics Course and a Senior Capstone Project Design Course

ERIC Educational Resources Information Center

Tickles, Virginia C.; Li, Yadong; Walters, Wilbur L.

2013-01-01

Much criticism exists concerning a lack of focus on real-world problem-solving in the science, technology, engineering and mathematics (STEM) infrastructures. Many of these critics say that current educational infrastructures are incapable in preparing future scientists and engineers to solve the complex and multidisciplinary problems this society…

Using Critical Incidents of Instructional Design and Multimedia Production Activities to Investigate Instructional Designers' Current Practices and Roles

ERIC Educational Resources Information Center

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.…

Assessment of Nitrogen deposition effects and empirical critical loads of Nitrogen for ecoregions of the United States

Treesearch

L.H. Pardo; M.J. Robin-Abbott; C.T., eds. Driscoll

2011-01-01

This report synthesizes current research relating atmospheric nitrogen (N) deposition to effects on terrestrial and aquatic ecosystems in the United States and to identify empirical critical loads for atmospheric N deposition. The report evaluates the following receptors: freshwater diatoms, mycorrhizal fungi and other soil microbes, lichens, herbaceous plants, shrubs...

Critical conditions for rill initiation

Treesearch

C. Yao; T. Lei; W. J. Elliot; D. K. McCool; J. Zhao; S. Chen

2008-01-01

Quantifying critical conditions of rill formation can be useful for a better understanding of soil erosion processes. Current studies lack a consensus and related rationale on how to describe these conditions. This study was based on the concepts that (1) the shear stress available for erosion at any given point is a function of the runoff rate, the slope steepness,...

77 FR 51814 - Draft Guidance for Industry on Generic Drug User Fee Amendments of 2012: Questions and Answers...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-27

... costs to industry. GDUFA enables FDA to assess user fees to support critical and measurable enhancements... critical and measurable enhancements to FDA's generic drugs program. GDUFA establishes fees for abbreviated... current thinking on generic drug user fee amendments of 2012. It does not create or confer any rights for...

78 FR 55261 - Draft Guidance for Industry on Generic Drug User Fee Amendments of 2012: Questions and Answers...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-10

... public and reduce costs to industry. GDUFA enables FDA to assess user fees to support critical and... assess user fees to support critical and measurable enhancements to FDA's generic drugs program. GDUFA...). The draft guidance, when finalized, will represent the Agency's current thinking on ``Generic Drug...

The Liberal Arts Department Chairs' Leadership Approach for Providing Faculty Professional Development

ERIC Educational Resources Information Center

White, Kevin C.

2017-01-01

Colleges and universities have a need to prepare faculty to educate students to be critical thinkers and well-rounded individuals. In accomplishing this goal, the undergraduate academic department chair takes on a critical role to assist with the process of faculty professional development. Currently, there is a call from different stakeholders…

Effectiveness of Critical Thinking Instruction in Higher Education: A Systematic Review of Intervention Studies

ERIC Educational Resources Information Center

Tiruneh, Dawit T.; Verburgh, An; Elen, Jan

2014-01-01

Promoting students' critical thinking (CT) has been an essential goal of higher education. However, despite the various attempts to make CT a primary focus of higher education, there is little agreement regarding the conditions under which instruction could result in greater CT outcomes. In this review, we systematically examined current empirical…

Fusarium torreyae sp. nov., a pathogen causing canker disease of Florida torreya (Torreya taxifolia), a critically endangered conifer restricted to northern Florida and southwestern Georgia

USDA-ARS?s Scientific Manuscript database

During a survey for pathogens of Florida torreya (Torreya taxifolia) conducted in 2009, a novel Fusarium species was isolated from cankers affecting this critically endangered conifer whose current range is restricted to northern Florida and southwestern Georgia. Published multilocus molecular phylo...

Religious Education in Russia: A Comparative and Critical Analysis

ERIC Educational Resources Information Center

Blinkova, Alexandra; Vermeer, Paul

2018-01-01

RE in Russia has been recently introduced as a compulsory regular school subject during the last year of elementary school. The present study offers a critical analysis of the current practice of Russian RE by comparing it with RE in Sweden, Denmark and Britain. This analysis shows that Russian RE is ambivalent. Although it is based on a…

Reflection in Action: Using Inquiry Groups to Explore Critical Digital Literacy with Pre-Service Teachers

ERIC Educational Resources Information Center

Lohnes Watulak, Sarah

2016-01-01

The challenge of preparing teachers and their eventual students to be successful, full participants in today's digital society is one that faces all teacher preparation programs. However, in the United States our current system of technology instruction in pre-service education focuses primarily on functional technology skills, and critical and…

What Would Liz and Larry Say? Performing Critical Approaches to Choreographic Mentorship in American Higher Education

ERIC Educational Resources Information Center

Duffy, Ali

2015-01-01

This paper argues that Liz Lerman's and Larry Lavender's approaches to mentoring student choreographers denote a shift in the philosophy of choreographic mentorship in higher education, because they reflect current concerns in critical pedagogy. My particular interest is in the relationship established between student artist and educator when a…

Using a Critical Reflection Framework and Collaborative Inquiry to Improve Teaching Practice: An Action Research Project

ERIC Educational Resources Information Center

Briscoe, Patricia

2017-01-01

This action research reports on a three-year collaborative learning process among three teachers. We used current literature and a critical reflection framework to understand why our teaching approaches were not resulting in increased student learning. This allowed us to examine our previously unrecognized and uninterrupted--and often,…

Schooling the Mean Girl: A Critical Discourse Analysis of Teacher Resource Materials

ERIC Educational Resources Information Center

Bethune, Jennifer; Gonick, Marnina

2017-01-01

This paper is a critical discourse analysis of teacher resource materials about girl bullying. The "mean girl" phenomenon has been widely taken up as one of the current key narratives about schools and school girls. This paper argues for the importance of understanding the origins of this discourse within behavioural psychology, which…

Wildland fire emissions, carbon, and climate: Plume rise, atmospheric transport, and chemistry processes

Treesearch

Warren Heilman; Yongqiang Liu; Shawn Urbanski; Vladimir Kovalev; Robert Mickler

2014-01-01

This paper provides an overview and summary of the current state of knowledge regarding critical atmospheric processes that affect the distribution and concentrations of greenhouse gases and aerosols emitted from wildland fires or produced through subsequent chemical reactions in the atmosphere. These critical atmospheric processes include the dynamics of plume rise,...

Critical Information Literacy beyond the University: Lessons from Service in a Women's Health Interest Group

ERIC Educational Resources Information Center

Fountain, Kathleen Carlisle

2013-01-01

Library instruction methods most frequently focus on teaching students searching skills to navigate the maze of library databases to locate appropriate research materials. The current theory of critical information literacy instruction calls on librarians to spend more of their time in the classroom focused on understanding the social, political,…

Practical Application of Critical Race Theory: A Social Justice Course Design

ERIC Educational Resources Information Center

Pulliam, Rose M.

2017-01-01

Social work education aims to prepare students to effectively engage with diverse people and groups. This article presents a practical application of critical race theory (CRT) toward that end. It describes a brief history of curricular approaches to teaching diversity and social justice and examines a few of the challenges with current curricular…

Critical Small Schools: Beyond Privatization in New York City Urban Educational Reform

ERIC Educational Resources Information Center

Hantzopoulos, Maria, Ed.; Tyner-Mullings, Alia R., Ed.

2012-01-01

Critical Small Schools: Beyond Privatization in New York City Urban Educational Reform features the most current empirical research about the successes and challenges of the small schools movement and the implications of such for urban public educational policy. Situated in a climate of hierarchical reform, many of the principles of the original…

IP Infrastructure Geolocation

DTIC Science & Technology

2015-03-01

unlimited 13. ABSTRACT (maximum 200 words) Physical network maps are important to critical infrastructure defense and planning. Current state-of...the-art network infrastructure geolocation relies on Domain Name System (DNS) inferences. However, not only is using the DNS relatively inaccurate for...INTENTIONALLY LEFT BLANK iv ABSTRACT Physical network maps are important to critical infrastructure defense and planning. Cur- rent state-of-the-art

Teacher Education and Critical Inquiry: The Use of Activity Theory in Exploring Alternative Understandings of Language and Literature

ERIC Educational Resources Information Center

Doecke, Brenton; Kostogriz, Alex

2005-01-01

This article explores the challenges of espousing a critical pedagogy within the managerial climate that presently shapes teacher education. Current discourses of professionalism are incommensurate with an understanding of the way that literacy practices are grounded in the social worlds in which both school and university students operate. Such…

A Critical Examination of the Process of Modifying the Curriculum of Alternative Secondary Educational Programs

ERIC Educational Resources Information Center

Ross, Michael

2014-01-01

This study, "A Critical Examination of the Process of Modifying the Curriculum of Alternative Secondary Educational Programs," was done with the use of action research to study (a) whether students currently participating in a continuation school believe their educational and career needs are presently being met; (b) the types of career…